S M O K E L E S S PO W DE R

AN D

N T R T I N G U N C O S U C O .

JA MES ATK IN N L N RIDGE SO O G ,

E H M E M . F O OF E L A D U E M M S CI VI L E N G ON . O S . IN T . N RTH NG N IN TIT T O F MINING AN D M ECHANICA L ENGINEERS ; AUTHOR OF ‘ A TREA TISE ON THE A PP LICATION O F W IRE TO THE ’ U O O F O D A E ‘ E A L ALL S S CONSTR CTI N R N NC INT RN B I TIC ,

E E . TC ” TC

E F N S O N 1 2 5 S T RAN D L O N DO N . . . . P , , ,

N E W "O K : 1 2 CORTL AN DT ST EE T . R , R 1 8 9 0 .

S M O K E L E S S PO W DE R

AN D

ITS INFLUENCE ON

G UN C O N S T R T I UC O N .

S M O K E L E S S POW DE R

ITS INFLUENCE ON

N N T RU T I N G U C O S C O .

JAME ATK IN N N RID E S SO LO G G ,

L H M EM . O F O H OF E LA D E M EM S V EN G. ON . S U . IN T . CI I ; N RT NG N IN TIT T O F MINING AN D MECHA NICAL ENGINEERS ; AUTHOR O F ‘ A TREATISE ON THE APPLICATION O F W IRE TO THE ’ O S U O O O D A E ‘ E AL ALL S S C N TR CTI N F R N NC INT RN B I TIC ,

E E . TC ” TC

F N O N 1 2 5 ST RAN D L O N DO N . E . . . SP , , ,

N E W "O RK : 12 CO RT L AN DT ST E E T . , R 8 9 0 1 .

I N the last chapter of my recent treatise on Internal . ” ’ Ballistics I alluded to the n e w powders which were then l attracting the attention of arti lerists . R eferring to their probable nature , I observed that the introduction of any ingredients which would either i n crease m the volume of gas or its te perature , or both together, would not only explain the apparently anomalous action of

O f these new powders, but probably result in the discovery a still more powerful agent .

Since then this has apparently been accomplished , and the ol d charcoal powder appears to be doomed to yield to this w more po erful rival . of l But the adoption this riva , whose properties are as yet W t only imperfectly known , is not to be viewed ithou anxiety . it u w and al l t Can be sed ith advantage , above with safe y, in o u r I f W W new type forged steel guns not, hat changes ill its use involve in gun construction ? What will be its effect as regards erosion ? H ow will it be affected by storage and change of climate ?

These are important questions, to which I do not pretend to give complete answers, but I hope that the following remarks w ill be of some u se in directing attention to the problems upon the solution of which future gun construction and ballistic practice largely depend . L J. . O N I A GR DGE .

’ EVE D A ZET T E JE SE" GR , R . u u 1 9 A g st 8 0 .

C O N T E N T S

— " I IN TROD CTOR . . U

II — AT R E O F T HE PO DER— PROD CTS O F COM P S . N U W U U

TION — POT EN TIAL — FORCE — COM PARISON W ITH

O LD POW DER S

III L ISTIC E F E CT OF N EW POW DERS FRE CH . BAL F IN N

AN D GE RM A G N S— C OMPARISON O F B N AN D N U . . ’ N O B E L S POW DER

I PRE SS RE S I N T HE C HASE ITH N E W PO DE R V . U W W COM PAR I SON W ITH PRE SSURE S FROM PE BBL E

POW DE R

—E FFE CT O F T HE N E W PO DE R O N E "ISTIN G N S V. W GU .

I —IN FL E N CE O F T HE N E W PO DE R O N T HE DE SIGN V . U W O F GUN S — VI L CON CL USION

APPEN DIC E S

POSTSCRIPT

SMOK EL E SS PO DE R W .

" INTRO DUCTO R .

1 of of . In few paths science has the march progress in the latter part of the nineteenth century been more remark

in O f able than the development material for warfare .

2 hal f . ou r Less than a century ago , the heaviest guns in

68 - service were the old pounders, weighing about five tons, f 2 f o 0 . o and firing, with a charge lbs powder, a spherical 68 to 1 500 lb . projectile which it gave a velocity of about feet — per second a ballistic effect equal to an energy of 1 060 foot tons . 3 Th h Of . e eaviest service gun the present day is the

- f 1 10 n o 1800 . O f ton gun , firi g a projectile lbs , with a charge 8 f of 100 50 . o 2 lbs powder , and a velocity feet per second,

O f - equivalent to an energy foot tons . 4 of . In the absence, in this country, the definite know ledge of the action and properties of powder (acquired through f M o . of the researches Sarrau , in France) , the adaptation

‘ vice versci of the powder to the gun, and, , the gun to the of so powder, has been a problem , the solution which, far of as it has been solved, is an empirical nature, so that the progress made in gun construction and powder manufacture has been of a somewhat erratic description .

5 Of of P or . After the day pebble powder came that 2 0 of of C and 2 , then that prismatic, succeeded by that

of so- brown cocoa, and finally that the called which B 2 P 0 WDER SMOKELESS .

a few months ago was looked upon as the pl us u ltm of

gunpowder for heavy guns . 6 . The line taken by gunmakers has been tolerably con

sistent throughout . They have ai med at reducing the strength of the powder, keeping down the pressure, and making up for

this by increased charges, enlarged powder chambers, and of increased length gun . Following ou t this line they have arrived at charges of

- one of . half, or more , the weight of the projectile , and at guns 30 40 of to calibres in length, but with a maximum pressure limited to about 17 tons per square inch .

7 n . In vain the argument has been urged that , by stre gthen of ing the guns instead weakening the powder, the same ballistic results could be obtained with greater convenience an d less expense . It has been shown , both theoretically and l practical y, that wire guns can be made as safe under a pressure of 30 tons as forged steel guns under a pressure of 17 tons ; but though a few experiments in this direction have W in been made at oolwich, they have been made a half

of u hearted way, extending over long intervals time, d ring ‘ which the construction of the type of forged steel gu n has been rapidly proceeded with , and may be said practically to f include the whole o ou r new armament. l of 8 . These latter guns are designed special y for the use such powders as the brown cocoa and that is to

say , powder of which a very large charge is required .

ou r 9 . Until quite recently artillerists have been in a

m . happy frame of ind They had got, or were very rapidly getting a sufficient supply of large guns of what they thought E "E to be the best possible type, and they had the new . . . d powder . the best powder in the worl . They had but to rest and be thankful . f G an o . 1 0 . That rest has been short duration From erm y and France came rumours of a n e w powder giving wonder or ful ballistic results, and at the same time smokeless, nearly so . 1 1 . Although much secrecy has been maintained with P DER SMOKELESS 0 W . 3

e t respect to the nature of the new powders , y the results have been so far made public, that it is no longer doubtful that they will give bal listic results largely exceeding those obtained from cocoa and with considerably reduced charges m and no excessive maximu pressure .

12 . ou r This being so, the question arises, how far are w new type guns suited to the new po der, and to what extent u shall we require a new armament, in order to reap the f ll advantage of the new powder ? It is proposed to discuss these questions by the light of such knowledge as the author can bring to bear upon the subject . 1 too 3 . This knowledge is limited to enable him to produce ” on m a a treatise the use of smokeless powder, but it y perhaps be useful in expl aining in some degree the difference of a roxi action between the old and new powders , and the pp n O f mate results obtai ed by the use the latter, both as regards ballistic effect an d the development of construction f o guns suitable to its use . 1 b 4. The su ject is divided into the following parts The nature of the new powder and the results of its de composition as regards the volume of gas produced per u nit of of weight, the heat evolved, the temperature combustion of ol d and a comparison with pebble powder, as a type the “ ”

P of . powders, the otential and Force the powder An examination of the ballistic effects of the new powder in French and German guns . ’ An inquiry into the pressures in the chase of Can e t s F R N 15 . . . cm Q . gun, with powder, and a comparison with a of d full Charge pebble pow er in the same gun . ff of u An examination into the e ect sing the new , powder in the existing new type forged steel gun . A few remarks on the influence of the new powder on the

of . design guns, and finally some general conclusions 4 SMOKELESS PO WDER .

— NATURE O F THE POWDE R PRO DUCTS O F CO M BUSTI O N O T NTI AL— F C — CO M ISO N ITH O L D O S P E OR E PAR W P WDER .

15 . The very remarkable results which have been recently G obtained from smokeless powder in France and ermany,

in point to an entire revolution artillery practice, as well as to a complete revision of the system of gun construction and the r formulae of inte nal ballistics . 1 ’ l 6 . ae M . Sarrau s formul of ve ocity and pressure , which are very approximately correct for charcoal powders , such as a l i the ordinary black and brown powders , are no longer pp cable to the case of t he new powders which give much higher l velocities with sma ler charges and reduced pressures . This must consequently lead to modifications in the proportions of d t guns, if it be a mi ted that these proportions are de pendent on the pressrire s existing in different portions of the gun . 1 n e w 7 . The superior results obtained from the powders the are mainly due to fact that, with them , nearly the whole of is the powder converted into permanent gases , whereas

r 43 . with the old powde s only about per cent is so converted, r the remaining 57 p e cent . being inert matter existing in th e

in of ff gun the form a very finely di used liquid, which , when c ool e d dow n , solidifies ; and is not only mainly the cause ‘ on e of the smoke, but also in all probability cause of the excessive erosion . 18 of . Although the chemical constitutions the new powders are kept as secret as possible, they are probably all ’ closely allied to that of NObel s smokeless powder, that is to

- . ll say , the main ingredients are nitro ce ulose and nitro c o r o f gly erine , to which is added nitrate perchloride r ammonia and a little campho . 5

1 An 9 . analysis of the reactions which take place on the of m explosion this ixture is given in the Appendix A , and from this it appears that the whole of the products consist of permanent gases and watery vapour , the volume Of which am ounts to about 705 cubic centimetres for each gramme o f powder. 2 0 . Further, that the heat evolved , after allowing for the of vaporisation the water, is about French units per d gramme of pow er. 2 1 h . The mean specific heat of t e products is found to be ° ° 1 989 m 8673 about , and their theoretic te perature about C . 22 B m of . Appendix contains a si ilar examination the k results of combustion of pebble powder , which may be ta en as a type of the old powders, from which it appears that the following are the results

u m of as from 1 of o d e Vol e g gr. p w r Gramme u nits of he at Me an Spe cifi c he at Theore tic t empe rature of prod u c ts

23 . The temperatures above calculated may be called the ” Theoretic or Potential Temperature . The actual tempera

- tures are probably not more than one half, owing partly to ff t o the cooling e ect of the walls , and partly the increase of the Specific heat at the high temperature and pressure exist ing in a gun ; but they probably represent the relative effect of the two powders as regards the temperature Of the pro

of ducts combustion . 4 n of 2 . The followi g comparison the two powders may therefore be made

'

Pe l e . N e l s bb ob .

° ° Vol um e of gas at 0 C and 76 metres from 1 gramme o f po w der Gramme u n its of heat evolve d from 1 gramme M e an specific heat of produ cts Theoretic temperature of produ cts 6 SMOKELESS P 0 WDER .

’ Potential of N obel s Powder .

” 25 P e u iva . By the otential is meant the mechanical q lent O f the heat developed by the combustion of unit of of or E weight the powder, Q when Q is the quantity Of E 436 u 772 E heat evolved, in French nities , or in nglish i un ties . Now it has been shown that Q units per

1714 l . gramme, or per ki ogramme 43 6 x 17 14 P 747 3 - Therefore, otential 1 000 metre tons

- f 5 . o or 109 . per kilogramme, foot tons per lb powder 2 6 ‘ . In the treatise on Internal Ballistics (page of P o f there is a table the otentials various explosives,

0 - l 46 b . and that of pebble powder is given as foot tons per , ’ or considerably less than the half of that of Nobel s powder ; as w as P of but, there observed, the otential an explosive must not be confounded with the mechanical effect which O w b may be btained from it, nor ith the pressure developed y m its co bustion in a closed vessel . ’ “ ” 27 . 50 At page , Internal Ballistics, the symbol f was M “ f W b . o used to denote hat is called y Sarrau, the force the powder,and it was defined by the relation

T P0 V0 O 273

9 1 3 ki 0 3 3 l . where 1 0 is the atmospheric pressure og per square decimetre ; h V0 is t e volume of gases from unit of weight at tem pe ratu re zero and atmospheric pressure ; T the O is absolute temperature of combustion . of Taking the kilogramme as unit weight, the volume Of ’ 3 3

705 1000 r 5 dm . x . o 70 gas is, for Nobel s powder, cm If the actual temperature of combustion be taken as 0 - f 2 o or 43 6 C . one half the theoretic value , , the absolute temperature 4326 273

’ nternal Balli tic b . . n n L n n 18 I s s JA L o rid . e o o o 89 . , y g g Sp , d ,

8 SMOKELESS P0 WDER .

the gun (assuming for the moment that there is no loss of

heat) , we have and making

9 and 15 1 p o ,

v z u o x so of of that, if the rate burning the powder were suitable, a 1 m full charge Of gravimetric density ight be fired, and yet the maximum pressure not exceed 15 tons per square inch , which would be attained when the projectile had moved m of ti es the length the charge along the chase . 31 l . Another advantage will probab y be the absence of fouling, as the whole of the matter is converted into gases, which leave little or no residuum in the gun . 3 — 2 . E rosi on . As regards erosion, experience must decide .

on the But it may be said that the one hand, products of combustion being entirely gaseous, instead of a mixture of fl W on gas and uids , will probable erode less ; hilst the other hand that the increased temperature and volume will tend

n to augment that erosio . W ith the new powder, the temperature no doubt falls more rapidly than with the ordinary powder, because the loss of heat being a function of the difference of temperature between the gases and the gun, is greater with high tempera

on a tures ; whilst the other h nd, with ordinary powder, it is quite possible that whilst the guns are expanding, heat is

u m comm nicated to the from the highly heated liquid, arising from the non - gaseous portion of the charge diffused through of t m them . The question erosion must herefore be deter ined SO far ou r by experience. as present knowledge goes, the smokeless powder in this respect appears to possess the advantage . P DE R 9 SMOKELESS 0 W .

BALLISTIC EFFECT OF N E W POWDERS I N FRENCH AN D ’ E M N NS— CO M SON OF B A D NOB L S I N . N G R A GU PAR . E O P WDER .

Form la Pr s a —I n 33 . u f or e su re nd Vel ocity t is ot surprising that the formulae which represent the ballistic action of the

Old powders are found to be inapplicable to the new powders , and although it is probable that M . Sarrau has already so modified his formula as to make it represent the action of w of the new po der, it is scarcely likely that the results his investigations will be made public at present . ‘ 34 m . Although the experi ental data published are very W limited, it will not be ithout interest to examine them care f of fully . These data are contained in notices o results E J 1889 firing, obtained at ssen in uly and August , with ’ f of Nobel s powder fired from four dif erent guns, and the

B . results obtained from the French N . powder fired from 1 1 0 5 . or cm. and cm guns, and inches calibre

respectively . 35 f . An examination o these results leads to a rather

remarkable conclusion , which, however , must be taken with all reserve . It is as follows 1 st . The muzzle velocity of the projectile is proportional to th of of the g power the weight charge.

2nd . The maximum pressure in the gun is proport ional to of of the square the weight the charge .

' V A w 7s (I ) 2 2 P B 20 . ( )

f s but The coe ficient A and B are not constants, are composed 1 0 P DE SMOKELESS 0 W R .

of f of various actors, which are functions the form , dimension, — in and rate Of burning of the grain fact, what are called by “ f — f M . Sarrau the characteristics o the powder o the weight of the b projectile, the cali re Of the gun, and the length Of of travel the projectile . ’ A In M . Sarrau s formula, he introduces another factor , of the gravimetric density, but this is in itself a function the

‘ O f weight of charge, and the calibre of the gun . ’ for Taking , for instance, M . Sarrau s monomial formula 9 8 ‘ ’ velocity, as given at page , Internal Ballistics,

V = H where H is a factor containing the force and charac t e ristic s of the powder ; weight of charge ; A gravimetric density l len gth of travel of projectile W weight of projectile

c calibre of gun .

A of Now, if equivalent length chamber ,

we ight of c harge c apac ity of c hambe r 0

substituting which in the above we get

H l 35 i 3, 0 NW

and it is the part within the bracket that is represented by A in In like manner Sarrau ’ s f ormula for pressure is

A 115 W 2 P K a 0 0 2 3 0 P 0 DE SMOKELESS W R . II

by substituting for A becomes

2 K a W 0 720 ° 4 { 7854 C A$

and the part within the bracket represents the B in

3 rn m 6 . From this it appears that in pass g fro the old to w e the new powders , the index of is incr ased from g to 2? in the Oxpressions for velocity and from to 2 in that for

pressure, an increase which might be anticipated from the absence of inert matter in the products of combustion of the n e w powders . The coeffi cients A and B of cou rse are different with dif fe re nt ff of guns, and di erent brands powder.

3 he 1889 7 . T results of the experiments made at Essen in ‘ ’ l ’ R Arti l ri . d e e . have been published in the evue , vol xxxv These experiments were made with Nobel’s powder fired from ff of four di erent guns, the details which are given in the

O . . following Table, N I

T A LE I B .

N um er of Gun b .

III .

C a lib re in inche s L ength of gun in calibre s W e ight o f gu n

of charge

of proj e ctile

From the results obtained at Essen the following Tables I I I . . II. and have been constructed of f and of Table II . gives the value the coe ficients A B formula (1) and (2) th I I I . e Table gives velocities and pressures, calculated 1 2 SMOKELESS P0 WDER . with these coefficients employed in formulae (1) and and E compared with the results actually obtained at ssen .

T A LE II B .

C effi c ient s N umber o . of B oun d s Grain of

Fi red P w der. . o

A T BLE III .

N o . of Rou nd Gun .

— VELOCIT"Fe e t per Second . 2089 2 17 1 179 8 20 14 2 104 2 165 1 797 2 01 8 1758 1 1 09 1 860 2 043 176 1 1 109 1 89 0 20 19 1 1 88 1 2 83 1417 15 17 1 174 1 284 1429 1535 1 883 2 004 2 136 2234 1 82 1 2 044 2151 2 259

RE UREs— T ns r u ar In P SS o pe Sq e ch . 8 4 6

k- ° H 44

T J ° C 33

P ° - l 28

nch E x erim n ts Fre p e .

38 n d . The experime ts ma e with the French smokeless ’ t w o C an e t s B . N powder . were made with of quick firing 3 15 m f 0 3 9 7 c . O 1 . guns ( cm ) inch and ( ) inch calibre ,

each of 48 calibres in length . DER SMOKELESS P 0 W .

u n of This is the total length of g over all , the length travel of the projectile being about 38 calibres

The powders used were all of the descript ion called B . N . ff In the inch gun , three di erent lots were used, which

for th ff f may account e di erence of the coe ficients A and B , whilst in the inch gun the powder was of the same

brand throughout .

f a n d . 39 . . o Table IV gives the values A B , and Table V the comparison of the Observed with the calcul ated ballistic s II I result , corresponding with Tables II . and . for the Nobel

powder .

T A LE I V B .

effi cie t Co n s.

i re Cal b .

l bs . lb s. L ot l 5 ° 28 t0 8 ° 58 L ot 2 to L ot 3 to L ot 4 17 ° 64 to 33 ° 08 89 ° O

T A BLE V.

R u nd o .

VEL O "— feet er se con CIT p d . 2001 2238 2 434 2562 2 057 2 273 2431 2586 2555 2582 2559 2574 259 1 2540 2 355 2536 2 6 15 2605 2405 2539 2627 2 627 1 962 2303 2428 2603 2008 2 325 2470 2 6 1 1

E E — n er u ar PR SSUR s to s p sq e Inch . 1 4 SMOKELESS P 0 WDE R .

40 ae 1 . From these tables it appears that the formul ( ) and

above given , represent very closely the results obtained t by experiments, and it is therefore probable tha the indices 0 ° 75 and 2 0 denote the relations between the weight of the u charge and the velocity and press re respectively, at any rate it is so in these guns .

41 R N . . A comparison may be made between the French

of and the Nobel powder, first as regards the energy the

l b. of projectile per powder, and second as regards the energy per ton weight of gun .

10 . For this purpose take the ( cm ) inch Canet gun, weighing 4620 lbs and compare it with the inch K 2310 l bs rupp gun , weighing ; the Canet gun being fired ’ R N K u n 1 557 with , and the rupp g with Nobel s powder of inch size of grain . on t wo It is assumed that the strain the guns is the same , that is to say, that the charge shall be such as will give the in t wo h same maximum pressure the guns, and that t is 18 17 pressure shall be tons per square inch, as in the fourth d f 15 V. o 26 roun Of this gun in Table , giving a velocity foot seconds . in u n Therefore, the Canet g , 2 6 152 x E ne rgy 1355 foot- tons ; "2240 which gives

' E e er ton of u n 657 1 f oot - to n rgy p g ns,

° - e r 1b of o d e 13 6 7 foo t o s . p . p w r t n

n K 42 . In the i ch rupp gun , in order to give the of 18 17 ° 1557 pressure tons, the weight of charge of the inch grain Nobel powder is found by the equation P whence

w 3 8 l 67 bs . , and the vel ocity with this charge would be

' 75 V 920 w 2537 fee t pe r se c ond ;

16 SMOKELESS P 0 WDER .

Consequently , had the guns been similar and similarly loaded , the total energy would have been

a s 1 355 so that not only is the energy of the smaller gun greater than the due proportion , but this is the case under the disadvantage f o being the shorter gun . 4 O it 7 . S far then as these experiments go, appears that the Nobel powder is superior in ballistic power to the powder. P DE 1 SMOKELESS 0 W R . 7

— PRESSURE S I N T H E C HASE W ITH N E w POWDER CO MPARISO N

ITH SS S F O M BBL O W PRE URE R PE E P WDER .

48 of t e x e rim n l . In the absence fur her p e t a data it is impossible to deduce the rel ations between t he velocity and

r h pressu e and the ot er ballistic elements, such as the length

Of of o f travel projectile , weight projectile , and calibre of the

ffi n c an gun, so that the coe cients A and B give above only ” b f n e made use o for similar gu s . 49 . It is very important to ascertain as far as may be o o f h p ssible, the distribution pressures along the c ase whilst the projectile is travelling to the muzzle . 5 0. As has already been shown , there is reason to belie ve in m that a close vessel impermeable to heat, the pressure fro the n e w powder would be about double of that given by the

Old black powder. Consequently, as in practice the maximum t of pressure is not greater, it follows tha the rate combustion m r ust be slower, thus giving more time for the p ojectile to of n get out the way, and by thus increasi g the space , keep down the pressure . It is also quite possible that the combustion may go on for m a considerable time after the maxi um pressure is attained , and that thus the pressures towards the muzzle may be greater than with the ordinary powders . I s 5 1 . As this a point of great importance relative to n the designing of guns, the question requires examinatio , so far as the limited experience available enables it to be n do e .

f 5 c m 52 o 1 . . Consider the case the ( ) inch Canet C 18 P D SMOKELESS O W ER .

F . . 15 . of 48 h B N of Q cm gun calibres wit . . powder, which the following are the ballistic elements :

’ A C N ET s Q . F. 1 5 GUN

Ca b e of un li r g inc hes . L ength of travel of proj ec tile Equ ivalent length of c hamb er 5 3

Capac ity of c h amber 1 500 cubic inc h e s . of ch ase 6 174 Total capacity of gun 7674

N umber of expansions

e W ight of charge l bs . W eight of projec tile 89 e o n s W ight f gu ton .

u e 5 s . M zzl velocity 27 0 f . 2750 2 "89

- Total energy 4665 foot tons . 64 - 4 x 2 2 1 - 0 Energy per ton of gun r o d pe 1b . p w er in Maximum pressure t ons per sq . .

53 . First, it may be asked, what must have been the mean pres sure in the gu n ? The total energy expended on the

l 4665 - m dd projecti e was foot tons, to which ust be a ed that

&c . expended in overcoming friction and expelling the gases ,

h 20 . a T is may be estimated at an additional per cent , m king

5598 - the total energy foot tons . ow of of 2 7 ° 4 N the area section the projectile is inches, and

the travel feet . Therefore , if p be the mean pressure,

5598 a I nch P " 10 92 tons per squ re .

4 N 5 . ext, if it be granted that the pressure in a close 78 ° 53 ro vessel would be tons per square inch, and that the p of m a ducts combustion act as a perfect gas, it y be inquired, at what point in the travel of the projectile will the pressure be reduced to the maximu m pressure of tons ? This can only be approximatel y ascertained in the absence of P0 WDE 1 SMOKELESS R . 9

e to of to n knowledg as the loss heat due cooli g, but from the f ’ V. considerations set orth in Internal Ballistics, Chapter , ul it wo d appear that this is not very great. Leaving this 1 out of is 1 loss account, there the relation where 12 p a and C o are the original and p and r the final pressures and t volumes, and as the volumes are proportional to the leng hs ,

r Now l e t l be the elation becomes ? o the length of the bore which would be occupied by the charge at 1 l the gravimetric density , and the distance from breech at which the pressure is reduced to p then

1 l ‘ 78 52 71 3 15 13 731 O

55 For r . ordina y powder the space occupied at gravimetric

1 2 ° r 1 7 7 . o density , is cubic inches per lb decimetre cube e r u p kilogramme, and when the charge is th s spaced it is said

of . to be gravimetric density equal unity If, however, the e be 30 spac any other number, say inches to the lb the gravimetric density is said to be

2 0 9 3 . 30

56 . It is as well to observe, however, that , with the French , s é ravimé ri ff n den it g t qu e has a di erent meani g . Densité gravimétriqu e is the weight of 1 cubic deci f n o ot o wn . metre powder, pressed together except by its weight Consequently it is evident that the densité grav imétriqu e of on it s o a given powder is dependent partly abs lute density, d n of F . . an o . or i e specific gravity, partly the size the grain F of instance, the French powder l has an absolute density ° 830 ° 870 l whilst its gravimetric density is to , whi st has s d has the which nearly the ame absolute ensity, a f 1 ° 03 1 17 gravimetric density o to . The equivalent of gravimetric density in French is not ” ” é ravimét ri u e d n é densit g q , but e sit de chargement . C 2 20 SMOKELESS P 0 WE ER .

l d 57 . o As is well known , with the ordinary powders 1 of cubic inches is the space occupied by lb . powder. But W h this is not so with the new powder . ith respect to this t ere i 1 l s . b much reticence It is, however, probable that . Of this m a 31 of powder y occupy about cubic inches space , and it is on h this assumption t at the following remarks are made . Though the conclusions arrived at may not be quite

SO f correct, yet they will be relatively , and will there ore be useful in the examination Of the ballistic properties of the e new powd r. 58 1 . Assuming, then , that the space occupied by lb . of 3 1 of l powder is inches , the length bore o occupied by the charge is easily determined . of The charge being lbs . , and the area the bore 27 4 inches, we get 3 1 L en t 3 - 4 g h 7 2 inc hes .

59 n 1 ' . Let, the , A D (Fig. ) represent the bore Of the gun the u of A B eq ivalent length the chamber, that is to say, a length of bore whose capacity is the same as that of the chamber, and B D the travel Of the projectile, and let A A be the length of the bore which would be occupied by the 1 to charge at gravimetric density , that is say, in the

present case inches . Then, if the powder were fired in be 78 ° 53 a close vessel , the pressure would tons per square inch ; but as the projectile moves away the space increases, and the contest between the evolution of gas and the inc re as

ing space goes on until a maximum pressure is reached . If

it be assumed that all the powder is burnt at this time, the C F point l , on the curve C; D, corresponding to this maximum of pressure, will denote the position the projectile, and the ordinates between C and D the respective pressures on the bore as the projectile moves to the muzzle the curve m F C , D being calculated from the for ula OK ELE SS P 0 WDE R SM . 2 1

a C * The ordin tes between B and are indeterminate, and

of of as of depend upon the rate evolution the g , the weight

projectile and other elements, but it may be assumed that approximately the pressure curve is represented by the curve of C B C, D, D, and that the point maximum pressure is at , ,

and that the total work done on the projectile is represented by the area of the cur ve multiplied by the area of the bore f o the gun . 60 . Taking the unit for abscissa in feet, and for the ordinate of C D in tons per square inch , the area the curves A 1 1 D is

2 10 2 - of found to be , which is the foot tons per square inch

T he as u m tion that the cu r e rom B to C is one - ou rth of an e lli se s p v f , f p h as be en fou nd by th e au thor to give ve ry satis factory resu l ts . 22 SMOKELESS P 0 WDER . bore ; and multiplying this by the area O f the bore

- 20 r . gives 5761 foot tons . If from this be deducted pe cent for the t n of resis a ce, friction , and expulsion the gases, there

i 4 2 - rema ns 6 9 foot tons for the energy of the projectile .

- This w as found by experiment to be 4665 foot tons . It may therefore be concluded that the pressure curve 1 un (Fig. ) represents, approximately, the pressure in the g 1 f 33 o . with a h . charge the new powder 6 1 n ow . Let this be compared with the corresponding diagram of the same gun fired with a full charge of pebble powder.

Th t of a 1500 e capaci y the ch mber being cubic inches, the

5 4 l bs a is in full charge will be , which, s shown

Appendix C, gives

Muzzle velocity 2570 fe et per se c . 2 ° o s Pressure on proj ectile 2 00 t n .

Therefore the energy is

4073 foo - ons t t , which gives

t - Energy per on of gu n foot tons . f de per 1h . o p ow r

62 . The following Table shows the comparison between N R . the and pebble powders in the inch gun .

En ergy . We ight Weight of of

24 SMOKELESS P 0 WDER.

" E FFECT O F T HE N EW POWDER ON E ISTING GUNS .

6 5 . Enough has now been said to show that the new powder is a revolutionary element in ballistic practice, and that it must consequently exert a corresponding influence n o gun construction .

6 I t r 6 . is therefo e very important to examine what will be the effect of using such powder in the present ne w type steel n d gu s, which were designed for the Ol er powder"s, such as the E . . E . black and brown prismatic, and the still later . powder

67 o . These p wders are characteristically weak powders, I s l ow that to say, they burn slowly and give pressures in f n guns . The ef ect is made up by largely increasi g the charges, and in order to give time for the entire combustion of and also for utilising the expansive force the gases, the guns are made very long. I n order to contain the large charges and also to reduce n the le gth of the gun , enlarged powder chambers are

e a of adopt d , with , however , the disadvant ge increasing the of m size the breech echanism , and the strain upon it . 8 6 . Now, in the first place, it may be asked what will be the effect of u sing the new powders on these guns ? It is m n e w in dd t o he ir clai ed for the powders that, a ition t quality of smokelessness, they will give vastly higher ballistic t t resul s, while they will strain the gun less owing to heir low maximum pressure, and this statement has been used

‘ as an argument against the necessity of adopting wire of guns, instead the usual forged steel construction . a of 68 . It is not intended to enter here into the questions of the relative cost production, the greater freedom from 25 SMOKELESS P 0 WDER .

a f n or t l tent de ects the quicker productio , the relative facili ies I n of repairs, all which respects the wire system has S i undoubted advantages. But it is desired to how that, f the f u ll advantage is to be obtained f rom the high bal listic ro erties o the new ow der it can on l be obtained b the p p f p , y y u se o com ara tivel hi h ressure a n d conse uentl ver f p y g p , q y , y stron uns such a s can on l be roduced b the w ire s stem g g , y p y y o constru ct on f i . of 69 . It is argued that the advantages the new powders may be utilised in two ways. 70 E . ither by retaining the present initial velocity with

of n or on the benefit a great reductio of pressure, the other hand by retaining the present maximum pressure of about 1 6 r tons per squa e inch, and thus obtaining a very great m increase of velocity, although ad ittedly retaining the f disadvantage o a great length of gun . 1 m 7 . The for er alternative is thought to be the better be l for field guns, as they cannot engthened without increase of of weight, which is inadmissible . Morever, the weight

be of cartridges could thus reduced, consequently more them d be a coul c rried ; whilst it has also been said that, as the on pressures are reduced , the strain the gun carriage would be relieved . f 2 . ff o 7 This last assertion is, however, a mistake . The e ect the strain on the carriage is proportional to the work done on i of l it , and this var es as the square of the velocity recoi ,

h caeteris a ribus t o whic velocity , p , is in proportion the v o f t t h elocity the projec ile, and has no hing to do with t e pressure by which that velocity is cre ated .

Consequently, if the muzzle velocity be unchanged the n a t he strai on the c rriage must be same, and if, by the use

d t he be a of the new pow er, velocity incre sed , the strain on the r d l car iage must be increase corresponding y . f 73 . O d This is course slightly mo ified by the fact that, in

t he of of f calculating velocity recoil , a portion the weight o

w el l the charge must be taken into account, as as the weight o f r ff the p ojectile, but the e ect of this will be comparatively 26 P E SMOKELESS 0 W ER .

of of small, and in the case increased velocity the projectile, will be far less than the increase due to the increased of velocity the projectile, which is not a function of the on r maximum pressure, but depends the mean pressu e , which is quite another thing. 74 . As regards the length of gun required for the new n powder, it is argued that by increasi g the pressure it would be necessary also to increase the length of th e gun to a practically impossible extent . 5 7 . But this also is erroneous, for it apparently rests on the assumption that the maximum pressure can only be by t increased increasing the weigh of charge, and that unless the length of the chase be correspondingly increased, part of ou t the charge will be blown of the muzzle unburnt . 76 N ow the h . maximum pressure depends, not altoget er, nor of h indeed principally, on the weight the c arge, but is fl ff of of chie y a ected by the rate evolution the gas , which is regulated almost ad libitum by m odifying the form and size of the grain . It is therefore quite practicable to increase the maxi h if . mum pressure, even the weight of c arge be diminished f 77 . This will be the more evident after the ollowing

f a n examination o the ction Of the powder in a gu . 8 7 . . 2 In the first place, reverting to Fig which shows the pressure in the same gun when fired with charges of 4 P R N 5 . . and lbs respectively ; in order to complete the curves the pressures behind the points of the maximum must be indicated . ’ 9 f r 7 . ae o According to M . Sarrau s formul ordinary powder, P on m if 0 be the pressure the breech, P the aximum of of E pressure on the base the projectile, making use ng lish unities of pounds for weight and tons per square inch for pressure,

w and W being the respective weights of charge and projectile . ' 27 SMOKELESS P 0 WDE R .

Another formula which is said to give better results , especially with slow powders, is

P _- =P ,

of 80 . Making use this latter formula and the weights 2 i . corresponding to F g , we find

d e P B. . 19 . For N pow r 0 P 1 P

F b e or peb l P0 P P .

From which the breech pressures corresponding t o the maxima in the diagrams are and 28 6 tons re spe c i l t ve y . off 0 0 Setting these ordinates at the breech the line 2 1 represents the internal pressure in t he gun when the pro e ctil e C l j is at , , and a ine parallel to it, such as g g, , represents the pressure when the projectile is at any other part g. 8 1 W . hat is most important to note is that whilst the m N . B . maximu pressure is considerably less with the powder ,

15 . although the work done is nearly per cent more, and 40 the powder charges per cent . less, the pressures are B N thrown so much further forward, that the . . powder if fully utilised will require a very differently proportioned one gun , , namely, in which there is about the same strength of bu t m behind the point maximum pressure, very uch t of greater streng h in front it .

82 . for 2 1 1 0 Taking instance the point gl , Fig. , at inches 10 from the muzzle, the pressure to be resisted will be 5 tons

B. 5 N . per square inch with the powder, as against % tons with the pebble . 83 . It is quite true that this pressure may be reduced by of B N reducing the charge the . . powder . 84 of . If, instead firing with lbs . , the charge was d 28 ° 52 reduce to lbs . , the velocity would be the same as the54 of that given by lbs . pebble powder, and the maximum 28 P 0 WE R SMOKELESS E .

14 o pressure would be reduced to t ns per square inch . The of 30 of length charge would be inches the bore.

85 . 3 The dotted curve, Fig. , is constructed from these 5 data, and being superimposed on the diagram for 4 lbs . of pebble powder, shows the respective action of the t wo

FI G 3 . .

powders in the same gun , while producing the same ballistic ff e ects . 8 6 to . It is evident that a gun designed sustain the pressures of the pebble powder is insufli cient in strength to sustain the pressures of the ne w powder in all that part of the chase commencing at about 180 inches from the muzzle. 87 of t he . To elucidate this, let an examination be made “ L K f R l M . o Gu n 6 B . . oya Factory gun, AR IV the follow ing ballistic elements

Calibre 6 inches . L en gth of rifling 1 27 4 Cap ac ity of c hamb er 1 3 6 c ub e inc he s .

Equ ivalent length of ditto inc h e s .

T otal c apac ity of gu n 5 105 c ub e inche s. Expansions

48 l bs . "E . Charge E . . 1 0 0 We ight of proje c tile .

Muzzle v elocity 1 980 feet pe r se c ond .

r s in . Maxim u m p re ssu re tons pe q . SMOKELESS P0 WDER . 29

88 . 15 t In order to compare this gun with the cm . Cane on gun, it must first be considered the supposition that it is t o f leng hened so as to make the travel the shot the same,

viz . inches , and then determined what would be the of E " 48 of . E . muzzle velocity with the same charge lbs . .

bu t of 89 powder with a projectile lbs. 89 d ’ . From such ata as are at the author s disposal it “ E "E appears that the characteristics of the . . . powder are

’ Making use of which in Sarrau s binomial formulae for velocity gives d V 2444 feet per secon .

0 m 9 . This is the velocity which is taken as a basis Of c o B N . . parison with the Canet gun fired with . powder

ow 1 N , by formula ( ) t v 198 w , and making V 2444 gives

w l bs .

Then by formula (2)

z P ° 0172 w ,

which making w gives

14 c P tons per sq . in h

u n for the Canet g . The comparison is therefore as follows

ar e i Ch . P ec t l g roj e .

u n C anet 15 c m . g in M ark I . V F. . R G . 6 lengthene d 30 P 0 WD SMOKELESS ER .

2 Thus, with 4 tons less pressure the Canet gun only u i requires abo t { f of the charge required of 9 1 . It remains, however, to be seen how the variations of pressure throughout the chase take place in the two guns,

had and for this purpose recourse must be to pressure curves,

u obtained as above described . These, tho gh not accurately correct, represent approximately the real pressures . The E "E curve for the . . powder is obtained by making use of ‘ ’ 172 the formula given in Internal Ballistics , page , with

FI G . 4 .

f 2 o 0 . allowance per cent for resistance , and is represented by 4 u . the f ll line in Fig . h 2 for t e B. N . 9 . The curve powder is Obtained as follows

- 2 1 The charge of 8 5 lbs . at gravimetric density would

28 5 x 3 1 883 occupy cubic inches, which is equal to 30 of b inches the ore, and the initial pressure in this space f would be tons per square inch . There ore the equa tion t o the curve is

u . 4 from which the c rve represented by the dotted line, Fig , is constructed . P t w in lacing the o curves over each other . as shown the

3 2 E P WD R SMOK LESS O E .

of 1 ° 35 At the second point it consists the A tube, inch B ° 2 1 5 . thick, and the 1 tube , inch thick 9 7 . According to the principles laid down in the Ofli c ial on of O 1886 Treatise the Manufacture rdnance, , no gun is

allowed to be strained beyond three - fourths of the elastic of 15 limit the material , which is fixed at tons per square

18 or inch for the A tube, and tons for hoops the

B tube . Consequently the allowed strai n is 1 5 x g tons 18 x n the for the A tube , and 9; to s for B tube . 98 d . Making use of the above imensions, it will be found by the usual formula that the greatest permissible pressure is 64 tons per square inch at inches from muzzle, and 32 6 983 tons per square inch at inches from muzzle . E "E 99 N ow . . . . , with the powder the pressures at these " points are about 10 tons and 8 tons per square inch re spe c tivel y , so that the gun nearly answers to the required condi

tions ; but w ith the B. N . powder the pressures would be 14 10 tons and tons per square inch respectively, an excess " 1 of 4 3 . 3, tons in the first case and about tons in the second 1 f of u n 00. It is therefore mani est that the strength this g insu fli cien t 28 ° 52 in the chase is quite for a charge of lbs . of N d R . powder, and any less charge woul give a less ballistic

result .

101 I t . 4 . may be objected that the dotted curve Fig is on bservation t theoretical, and not based actual , excep as the regards maximum pressure, and t at the actual results of firing have not shown the guns to be too weak . 1 02 W a . ith regard to the l st objection , it has not much on n weight. A gun may go firi g for a greater or less time t or bu t without burs ing any visible damage, not the less surely is . it injured every time that it is strained bey ond the W elastic limit, and this seems to be fully admitted at oolwich , w Offi here, as stated in the cial Treatise, the practice is to limit the maxim um strain t o three - fourths o f the el astic t f n for limi . If, there ore , the present guns are not too stro g the present powder, and if the pressure curves be even P 0 WDER SMOKELESS . 33

approximately correct, the guns cannot safely be used with t ff t the n e w powder with increased ballis ic e ec . 103 c . The objection against the curve as theoretical arries N more weight. ot only is it theoretical , but it depends o n the assumption of the pressure in a close vessel being

° 78 52 tons per square inch . 0 n The reason for this assumption is give above, and there is nothing in it which appears either improbable or inconsistent with such other facts as are known with respect to this powder . The law of decrease of pressure by which the ordinates and the curves are calculated is a rational law, and in all pro hability approximately true for the powder gases . 104 . Moreover, the velocities deduced from the area of these curves (due allowance being made for other resist u a ces) agree very well with the observed velocities, and of consequently, whatever be the real form the pressure u of curve, its area m st be approximately the same as that the 4 dotted curve, Fig . . 1 05 I n . the next place, the final ordinate at the muzzle must be the same (if all the charge is consumed), but it is quite possible that the point of maximum pressure may be to 4 further the rear than shown in the curve, Fig. . of h m Indeed , the curve may possibly be suc a for as 5 of shown in Fig . , A B C, the area which may be the same E n u as that of A B, C . ve in this case the press res in front of w the chase must be greater than ith the other powder. of It may also be Observed that, to permit the possibility of of A B C of of a curve the form , the rate the evolution ff gas must be very di erent from anything previously known . 1 n 06 . There is another strai besides the bursting strain f r o . which must be provided , viz the longitudinal strain in the chase of the gun arising from the friction of the products of combustion rushing along the muzzle . 1 0 of n 7 . The importance this strai has never been recog nised - to b by gun makers, nor do there appear have een any

experiments made to ascertain its magnitude . In Internal D 34 SMOKELESS P 0 WDER .

Ballistics ’ reasons have been given for attributing to it a

very considerable magnitude, and indeed there can be little

doubt on the subject. 1 08 of . To what extent the magnitude this strain will be affected by the use of the new powder can only be c onje c ur d n n t e m t e . O o the e hand, the volume, pressure, and

perature of products of combustion are considerably greater .

FI G . 5 .

On of the other hand , these products consist nearly perfect

f of n gases, and the coe ficient frictio will probably be less than in the mixture of gases and finely diffused liquid m f arising fro the combustion o the Old powders.

1 9 f n of 0 . The subject o the longitudinal strai is such importance that it is i nconceivable to the author that gun makers have taken no steps to ascertain its magnitude and h relation to t e other ballistic elements . SM OK ELE P DE R SS 0 W . 3 5

INFL NC O F T HE N E W O ON T HE SI N O F NS UE E P W DER DE G GU .

1 1 0 . It has been shown that no great improvement in f ballistic ef ect can be looked for, consistent with safety, an d n e w with the present guns the powder. It is, there m t fore, proper to give so e attention to the subjec of a design of gun suitable for the development of the n e w explosive .

1 1 of - 1 . U to p to the present, the idea gun makers seems — be running in the ol d groove l o w pressure and length of gun .

. F 1 . The French 5 cm . Q Canet gun is called a gun of

48 . calibres, but that is the length over all The real length is as follows

277 “ 5 Chamb er 50 inche s c hase inc he s .

It is only slightly chambered, and the equivalent length of the chamber is inches . The total capacity of the gun 7674 of 1 5 00 is cubic inches , and the chamber cubic inches ,

un of 5 1 16 so that it is a g expansions, that is to say, a very long gun .

1 12 . n But long guns are very inconvenient and objectio able , at especially sea , and the question arises whether it would be practicable to take advantage of the n e w powder in a short gun , even though it were at the expense of decreasing f the efficiency per pound o powder .

- 1 13 . S The gun may be hortened in two ways First, by an enlarged powder chamber, which, however, has the dis D 2 E D 36 SM OK EL S S P O W ER .

advantage of increasing the strain upon the breech apparatus ; or the m , secondly, by increasing maximu working pressure . 1 14 . To what extent this may be done cannot at present be be solved in a general form , inasmuch as the relations tween the ballistic effect of the n e w powder and the ballistic of elements, such as calibre of gun , travel and weight pro e c til e of n e w j , and characteristics the powder are unknown

in this country. 1 15 R m of . ecourse must therefore be had to the ethod l m t curves, and to such i i ed information as is given in the

u n in the r f published res lts co tained fi st part o this paper . The question will therefore be confined to a gu n resembling ’ F . n . . f Ca e t s 1 5 . o M cm Q gun with a calibre inches , and travel and weight of projectil e inches and 8 9 lbs . 11 h 6 . Suppose (w at might be easily done) a wire gun to be m ade so as to give the same margin of safety under a pressure of 30 tons as the Canet gun under a pressure of

tons . P ° 0172 w P 30 By the formula , and making , we t 198 w 3253 f. s . w . V get lbs , and consequently O f 45 5 Let the capacity the chamber be cubic inches per lb . of a powder, which is the s me gravimetric density as in the I I . last round of the Canet gun . (See Table ) t 1 500 The capaci y of the chamber is cubic inches, and the 53 of equivalent length inches, and the length charge

n h 47 i c es .

W d . 6 u ith these ata the curve Fig is constr cted , the area

of 301 which is , which multiplied by the area of the pro

- j e ctil e gives 8247 foot tons . 20 o Deducting, as before, per cent for resistances, expulsi n

6595 f - of &c . gases, , there remains oot tons, which corresponds l of 3271 n to a ve ocity feet per inch , which is very early the V 1 98 w t velocity found by the formula . 1 1 of be o 7 . The weight this gun would probably ab ut

7 on r 4 tons, for the wire const uction it could be made con

s ide rabl y lighter in proportion than the Canet gun . P D R 37 SMOKELESS 0 W E .

Therefore the relative effi ciency of the two guns woul d be

E ner ie g s .

sc r n De iption of Gu .

ane C t Q . F.

- Showing the decided advantage of the high pressure gun . 1 18 of . It may now be inquired , what would be the length the proposed high - pressure gun which would have the same ballistic power as the Canet gun This m ay be approximately ascertained from the curve 6 Fig. . The difference of energy imparted to the projectile is

1933 f - t o 20 oot tons, which must be added per cent making

FI G. 6 .

- h d 2320 foot tons, w ich divi ed by the area gives

- e nd of foot tons to be deducted from the muzzle the curve , and since the mean pressure near the muzzle is about

10 tons per square inch, the length to be deducted is

r 1 03 of feet o inches, so that the travel the ° 1 0 projectile would be 122 5 inches and the total length of the

un 181 283 h g over all, about inches instead of inc es in the

Canet gun . 38 P 0 WDE SMOKELESS R.

1 19 . t wo u the The guns wo ld have same ballistic power . h f The weig ts would be about the same, and the only dif erence

l f 41 of wou d be the expenditure o s lbs . powder instead of

lbs . 1 20: With reference to the higher pressure proposed to be used it is to be observed that the maximum pressure in a gun ’ depends not so much on the charge of powder as on Sarrau s

Ot characteristic , or rather on which is in his notation

of a ffi Q, in whichf is the force the powder, a coe cient

on of r com depending the form the grain , the time of total

i r bu st on of the grain in f ee air.

12 1 r . It is, therefore, Obvious that with any given powde 2 w Cr for hich f has a fixed value, the value of may be modified by a corresponding modification of a and the first of d on of on which epends the form grain , the second its density and least dimensions . ’ o f It is, therefore , simply an object research to make a

d of t C pow er which the charac eristics , will give the required pressure . 1 22 A s . is easily seen , the higher pressure is given by the

r ff lower value of , whilst at the same time it may be e ected by giving such a form to the grain as will give a higher f O value o . The practical result Of decreasing 7 is that the evolution of gas is quickened, and the pressure rises at an earlier of ro e c period of the course the projectile, because the p j m ou t of tile has not had ti e to move the way . 12 f 3 . o It is , therefore, evident that the question the deter of mination of the characteristics these new powders, and the size and form of grain suited to the different calibres of one of fi rst - guns, is rate importance, and without which future ballistic progress must be a matter of hap - hazard and danger.

40 SMOKELESS P 0 WDER .

(2) That the erosive action on the guns will probably be less . (3) That its use in existing guns of the new forged steel type will n ot lead to any considerable increase of ballistic ff t without considerable risk of e ec , owing to the increase n of pressure developed in the fro t part the chase, although m the actual maximu pressure on the gun may be less . (4) That to utilise the high ballistic powers Of the new powders very strong guns will be required , and that such guns will have to be much stronger in f ron t of the trunnions of than those the new type forged steel guns . That to arrive at very high ballistic results it is not of necessary to have guns inordinate length, but by the of of m adoption higher initial, instead low and ore uniform of 30 00 pressures, velocities feet per second and upwards are attainable with perfect safety . 1 2 8 . In bringing these remarks to a conclusion, the author to may perhaps be allowed to give expression Opinions, which o wn n of in his mind amou t to convictions, as to the future gun construction and ballistic effects . 129 t of . The firs these is, that low maximum pressure is a ’ no raison d etre f mistake . It has except the weakness o the of gun . It involves a length gun which for naval use “is m ost objectionable . No doubt M . Canet has achieved very

15 . F brilliant results with his cm . Q . gun, but this gun is ” n u n 23 feet 4 i ches in length over all . A si milar g f 12 46 t 8 o inch calibre would be about fee inches long. ” of Similarly loaded it would fire a charge R N . powder 2 f 71 . o 2 64 . lbs , and a projectile of lbs , with a muzzle velocity f of 2750 . o feet per second, giving a muzzle energy

- or 848 3 - u foot tons, foot tons per inch Of circ mference . N ow as 15 , was shown in a cm . gun of equal power, m of 3 0 firing with a maximu pressure tons per square inch , ” d 15 of 1 woul be feet long, and a similar gun 2 inch calibre 3 0 46 would be feet long , as against feet 8 inches for the u low press re gun . There can be no doubt which gun is the most suitable for naval service . P DE 41 SMOKELESS 0 W R .

130 u of a . A second conviction is, that g ns very large calibre are a further mistake, and the author ventures to thin k that a 9 - inch or 10 - inch high pressure gun would be sufficient for any effect that is required again st the heaviest fl armour a oat . 1 31 . A third conviction is, that in order to utilise the new powders recourse must be had to the wire system of c on of su fi cie nt struction , by which alone guns strength can be

Obtained . 1 2 3 . no Lastly , he would express the Opinion that time should be lost in carrying ou t such a series of experiments a as will enable formul e analogous to those Of M . Sarrau to for n e w for be constructed these powders, and also the determination of the tensile strain on the chase caused by of of the friction the products combustion . ( 42 )

ENDI APP X A.

’ DECO MPOSITION OF NO BEL S POWDER As A T "PE OF THE

SMO K ELESS PO WDERS .

N ’ N 1 47 1 8 8 1 00 According to obel s specification, o . / , grammes Of powder contain

N itroglyc erine N itroc e llu l ose Pe rc hloride amm onia C amphor

After explosion these give rise to new products, viz .

th itr l eri From e N og y c ne .

Carbonic acid N itrog en Oxygen Water

T otal 23 10

From the itr ce lu l o e N o l s .

Carbonic ac id Carbon ic oxid e Hydrogen N itrogen Water PP 43 A EN DI "A .

r m the Cam hor F o p .

Total

From the Perchl orid e of Ammonia

Total 50 35

Certain of the products of the camphor and perchloride e unit , and the final result of the decomposition is

Carbonic ac id N itrogen Wate r Chlorine Oxygen

Total 100 00

O L M OF G S O S O CTS V U E A E U PR DU .

The volume of the products in the last paragraph at ° 0 Centigrade and 0 ° 76 metres of mercury would be

Cu b . Decimetr es. Carbonic ac id N itrogen Wate ry vapou r Chlorine Oxygen

70 51 44 APP N DI "A E .

f 1 of of There ore, from gramme powder the volume gas ° 7051 r 05 o 7 1 . cubic decimetres, cubic centimetres In the above the wat er has been considered as in the state of of a permanent vapour, though course that is impossible at ° 0 of rodu ct s of c om Centigrade, but as forming part the p b ustion it is always in the gaseous form , and may therefore

n properly be comprised amo g the gaseous products , proper allowance being of course made when the evolution of heat for in of is considered, the heat absorbed the vaporisation the water .

HEAT EVO LVED PE R GRAMME OF PO WDER .

R 100 of d everting to the grammes powder, the heat evolve is that evolved in the formation of grammes of car

n f bo ic acid and grammes o water . The first contains of of grammes carbon , and the second grammes hydrogen . Consequently the heat evolved is

F om Ca bo n Ce t ade r r n u its n igr . Hyd rogen "

T otal 1 87 4 but the heat required to vaporise 25 ° 4 grammes of wate r is

° 63 1 s Ce t ad x unit n igr e .

° 171 48 or for Deducting which there remains units, 1 of 1 ° 7148 gramme powder units Centigrade .

T M T OF O CTS E PERA URE PR DU .

This can only be given as a comparison with othe r n ot powders, and as the real temperature existing in the gun under circumstances when the loss of temperature due to cooling and the specific heat at very high pressure and tem r ar n pe rat u e e both unknow . 4 4 PI HVDJBC A 4° 5 P . .

The temperature now in question is what might be called the potential temperature or the theoretic temperature , and is calculated on the assumption that there is no loss by cooling, and that the specific heat remains constant . Under these conditions it may be compared with the potential or theoretic temperature of ordinary powders .

’ — A N oBEL s POWDE R M EAN SPE CIFIC HE T O F PRODUCTS .

Carbonic ac id x ° 1 72 N itroge n x ° 1 73 Wate ry vapou r x ° 337 Chlorine ° 086 Oxygen ° 155

19 9 Therefore the mean specific heat 0 .

T M E PERATURE .

Since the heat evolved is units per gramme, or

units per kilogramme, the temperature will be

8673 C. 1 99 A ENDI PP X B .

P In order to compare with the Nobel powder, ebble powder

is taken as a type of the Old powders, and its composition , as given by Noble and Abel in their Researches on Explosives R ’ Trans . oyal Society, is

1 ° 0000

° f of 1 And the products o combustion gramme at 0 Cent. and metres of mercury

Carbonic ac id C arbonic oxide N itrogen Su lphydri c ac id Mars h gas H ydrogen Wate ry vapou r

441 0 285 9

The remaining products consist of about ° 56 gramme of fl of salts, chie y potassium and sulphur, which whilst in the gun are in the form of a liquid diffused throughout the gases " and at the same temperature .

A E NDI C PP X .

EL OCIT"AN D PRESS RE I N 5 5 I N CH 90 .F AN E T UN ITH V U Q . C G W 4 LB P PO E R D . 5 S. . W

B a llis tic El ements .

FORM FOR E LOCIT" I B LA . e na a c U V nt r l llisti s , p .

3 ‘ 1 I ‘ w s A e c s 1 6 V M the refore

2 FORMULA FO R PRE SSURE P K a A

1 54249 Dedu e t

10 Wf “ ° 28 85 1 - s l og P 1 34237 P l og V 2 f V 570 . S . POSTSCRIPT .

W H ILST the above pages were passing throu gh the pre ss ‘ t he Unit e d I have read an interesting article , in Service of 1890 P R Magazine August , by rofessor Lewes, of the oyal “ on P t P Naval College, The resent Sta e of the owder ” P ’ Question . Agreeing generally in the rofessor s con e lusions , I must take exception to one or two of his remarks . I do not agree that a perfect powder is o ne of which the production of gas goes on until the projectile reaches t he

l of u n . muzz e the g Such a powder would be very wasteful, and would carry the region of high pressure much too far for w ard in the gun . a t he Then , gain, I think there must be some mistake in diagram which is given as representin g the pressures in the m P . P . chase with the three powders 2 , Bl ris , and Br . Cocoa of The areas the three curves A, B, and C , if correct, must z r t be proportional to the muz le ene g ies of the projec ile . The velocities are proportional to the square roots of the re s e ctive of p energies , that is to say, to the square root the areas of the curves . N o w are , these three curves represented by the relative 76 of w numbers , and the square roots hich are 2 22 8 7 8 . , and , respectively of 1 608 Consequently , assuming the velocity feet per th P t he second to be correct for e 2 powder, other velocities w P m as represented by the curves ould be , Black ris atic 1 6 83 1586 feet, and Brown Cocoa feet per second , instead o f 1708 and 1 798 feet per second as given by Profe ssor t u t Lewes . It is herefore evident that there m s be some d mistake in the curves shown in the iagram . I am very gla d to see that Professor Le w es insists strongly o n the import ance of the question of t he stability of the new powders . LON DON P ED B"W LL AM LOW ES AN D SO S LIM E D RINT I I C N , IT ,

STA N FO RD s rRE ET A N D CH AR I N G C RO SS. B y t h e s am e A u t h or .

A TREATISE ON THE APPLICATION OF WIRE

TO THE CON STRUCTION F DN N E O OR A C .

P ice 2 r 53 .

INTERNAL BALLISTIC S.

i e Pr c 1 83 .

D F S 1 25 ST RA D L O ON . E . a . N . PON , , N , N

"RK : 12 CORTL AN DT STREE T . N EW O , THI S B O O K I S DUB O N T HE L A S T DATE S TABI PE D BE L O W

AN I N I T I A L FI N E O F 2 5 C E N T S

W I L L B E A S S ES S ED FO R FA I L U R E T O R E TU R N T H IS B O O O T H D T D U T H P A L " K N E A E E . E EN T W IL L I N C R EA S E T O 5 0 C EN TS O N T H E FO U R T H D A "A N D T O O N T H E S EV EN T H DA "

O V ER D UE .

LD 2 1 —l oom