OcToBER 28, 1897] NATURE

LETTERS TO THE EDITOR. Hence we haYe two broad results : ( r) the excessive preponder· ance of fillies over colts; and (2) that the colts more frequently The Editor does not hold himself responsible for opinions ex· resemble the colour of 1 he dam than do the fillies. For every pressed by his correspondmls Neither call he undertake hundred fillies there would be 102 colts resembling the dam. to ,-eturn, or to correspond with the writers of, rejected Truly this is not a large difference, but, based as it is upon over manuscripts intmded for this or any other part NATURE. of 1500 cases accurately described and exactly tabulated, 1t seems ,\To notice is taken o.f anonymous commtmications.] worth calling attention to, as it carries Mr. Galton's analysis a On the Meaning of Symbols in Applied Algebra. step further, and points to the possibility of a further develop• ment in an exceedingly interesting branch of heredity. REFERRI:-LEONIDS. Strange Instinct of Fear in the Orang. D URING the next few years a large amotint of attention THE following circumstance which occurred at the Zoo on will be given to meteoric astronomy in general and Sunday last, and was \\itnessed by Mr. W. E. de Winton and to the great shower of Leonids in particular. The pre• myself, is perhap3 worth putting on record. sent may, therefore, be an appropriate time to refer to a We were watching and making friends with the baby orang, few points connected with this interesting branch. It and my wife was standing by, holding on her hand a muff has often occurred to the writer that it would greatly factured out of the skin of the Indian flying-squirrel, with the unstuffed skin of the head to the front, and the bushy tail facilitate the comparison of different materials if observers hanging loosely over it. Suddenly, but quite gently, she adopted one uniform method of recording meteor-flights. stretched out the muff towards the orang, but at the sight of Some. merely give estimated compass bearings, and a the advancing fur a light of unmistakable terror sprang into the rough guess at the altitude and inclination of path, others creature's eyes. Upon repeating the experiment, the ape give the place and direction according to conspicuous promptly rolled over backwards as the quickest way of removing stars near, others simply mark the courses on a map himse lf from the immediate vicinity of the terrifying object ; without reading off the individual positions, while others then gathering himself together, climbed up the branches of his give the R.A. and Dec!. of both beginning and ending of tree, and retreated to the back of the cage, keeping all the every object observed. It would be a great advantage while a wary and frightened eye upon the mull, as if in fear of if every one tabulated results according to the latter an attack from behind. It is interesting that the whole per• method. It can easily be done if the tracks, as observed, formance was carried through without the utterance of a sound on the part of the orang ; but that he was acting under the in• are pencilled upon a celestial globe or star chart, and the fluence of fear, there is, I am persuaded, no doubt. His positions read off; and this is a much more exact method behaviour, in fact, reminded me irresistibly of the behaviour of than describing the flights by stars near which they a friend's little child of ten months old, who evinced similar happen to pass. signs of fright upon being shown a toy fur monkey for the Another point is that the accurate observation of first time. R. I. PococK. meteors demands a considerable amount of practice. It Natural History Museum, October 25. would, therefore, be a most useful prepara tion for in• tending observers of the Leonids if they carefully Hereditary Colour in Horses. watched the Perseids of August, Orionids of October, MR. FRANCIS GALTON'S very characteristic article in the and some other prominent displays, and gained a little current number of NATURE, page 598, upon hereditary colour practical experience of the work. They would find it of in horses, appealed to me with more than usual interest, as for material assistance to them, and would enable the some months I have been planning a somewhat extensive inves• Leonids to be observed more expeditiously and-correctly tigation into the hereditary transmission of various characteristics than must otherwise be the case. Accounts a re some• amongst the higher members of the animal kingdom, including times published of meteoric showers by persons who are that of colour in horses. reporting· a perfectly novel experience, and it is not too It may Le of interest to your readers if I summarise a recent much to say that such descriptions are useless as regards quite preliminary investigation upon the same matter, which I many essential details. A perfect novice may of course shall hope at some future time to work out more t!wroughly. I may add that, contrary to what Mr. Galton experienced with stand and count the number of meteors visible, and may the data he used, all the grey foals in my data did not come from be capable of describing a star-shower in a general grey dams. way, but he is heavily handicapped when it comes to An examination of the offspring, numbering in all 1566, of recording the more difficult features with precision. one special· class of mares shows that there were 686 offspring What photography may achieve in meteoric work we can which resembled the general colour of the dam, and 88o which not definitely foresee, but it is quite certain that the proper differed ; or a preponderance. of 28 per cent. dissimilar. Of observation of meteors, as at present conducted, demands these:- the work of a lifetime. A man must watch for meteors 313 colts were the same in general colour a> the dam. all night, and suitably record them, and by day he must 394 " " not , " analyse the observations and determine the radiant 37 3 fillies , t ht same points. The observer need not, perhaps, absolutely 486 , , flO! ,, isolate himself from

© 1897 Nature Publishing Group JVATURE LOcTOBER 28, 1897 branch is such an extremely difficult one, em!::Jracing, as return of the Leon ids is to photograph the meteor group it does, some thousands of streams which exhibit many of November 1866 in space, and an excellent ephemeris different peculiarities, that in order to grapple with the of its nearly stationary position in Libra and south• subject successfully he must make it his constant care eastern limits of Virgo, during the first four months and the object of his earnest efforts and thoughts during of 1897, was given in Monthly N otices, !vii. p. 70-2. many years. Some people will regard the idea as little more feasible Fortunately the Leonids are to be classed amongst that than opening a correspondence with the inhabitants of description of meteors comparatively easy to observe and Mars, and certainly there appears very slender prospect record. They leave streaks for a second or two, and I of its successful realisation. The experiment ought, from these the directions are to be determined with great however, to be tried. Let us support e1·ery project which facility and precision. It is also a fortunate circumstance has a possible side to it, for it is quite clear that many that the radiant point is surrounded by the well-known things deemed beyond our reach are capable of attain• stars in t,1e Sickle of Leo. The lines of flight may ment by persevering efforts and proper means. Novel therefore be readily carried back in the correct direc• attempts of this kind, if seemingly chimerical, should not tions by projecting a straight wand upon the streaks, and be hastily condemned or necessarily considered as vain noting their points of convergence relatively to the stars labour. Mr. Roberts's photographic search for a trans• named. Neptunian planet was a novelty, and it proved vain The writer has usually found the radiant very definitely labour ; but who will say that it ought not to have been and sharply defined, and it can be readily fixed to within undertaken ? The same may be said of Mr. Barnard's 2 ° of probable error. But naked-eye observation is similar search for a satellite to the moon. To look for a capable of much more accurate results than this, if, fifth satellite of Jupiter was decidedly a novelty in these during a pretty active return of the shower, the observer modern times, and yet it proved productive. Let, then, will independently fix the radiant during, say, successive new researches like these have our encouragement; for if half-hours of the night; he will in this way get eight, ten, they do not always succeed, they stimulate our interest or twelve posi'tions, from which he may derive the mean and enthusiasm, and make the science more attractive by place of the radiant to within about ;ic of error. imparting to it a welcome freshness and, perhaps, a touch The Leonid radiant is sometimes described as very of romance. diffuse ; but this is a false effect brought about by two As to the practical aspect of the question, it is fair to circumstances which, if properly allowed for, would leave conclude that the Leonid group of 1866 is too faint an a very definite and satisfactoty position. One cause of object to be ever impressed on a photographic plate, its apparent diffusion is that meteors are attributed to it especially when its distance is so great as during the which really belong to the minor showers in Leo and the past spring, for on March I this was equivalent to surrounding region, of which quite a large number exist. 8oo,ooo,ooo miles, and not far short of the mean distance They display similar visible characteristics to the Leonids, of Saturn! In the great meteor storm of November 27, and can only be dissociated from them by the exercise 1885, when the meteors were more thickly congregated of extreme care in noting their directions of flight. In than in the Leonid shower of November 13, r866, Prof. Popular Astronomy, val. i. p. 298, I gave a list of sixty• Newton computed that "the space in the meteroid eight meteoric radiants situated in various parts of the group corresponding to each single visible meteor was in heavens, and active during the period November IO-I 5 ; the densest portion of the group, a cube whose edge is 32·8 and in The Observatory, vol. xx. p. 3o6, a table of kilometres or 20'4 miles." This means one small pebble seventy-two circum-Leonid showers was published. in twenty miles of space ! The degree of illuminating Those which chiefly affect the determination of the power exhibited by a group of these bodies, separated by Leonid radiant are placed near lJ and • Cancri, J< and such distances, must be infinitesimally small. If any one Ursre Majoris, X Hydr;e and 1r, X, or and {3 Leonis. were to attempt to photograph Tempel's comet (1866 I. ), The meteors are swift, and usually leave streaks. An• on its return journey, the chances of success would be other contributing feature to dispersed radiation is found far greater, for though the comet has still to run eighteen in the unavoidable errors of observation. Great care and months before reaching perihelion, it is nearer to us habttual practice can, however, reduce these to small than the meteor group of r866, and must be infinitely limits, and it will be found that the radiants derived from brighter, as it doubtless represents the richest part of accurate materials will be pretty sharply defined. the stream. We must remember that Tempel's comet The probable error in the case of different observers passed its perihelion on January II . 1866, while the must, however, vary to a considerable degree, for prac• meteor-group reached it ten months afterwards ; and it tice cannot equally eliminate inaccuracy from amongst is quite fair to suppose that the meteoric train of the them all. In catching and retaining correct impressions comet, at a distance of some hundreds of millions of of meteor flights, natural aptitude exercises an important miles from the nucleus, must be relatively tenuous as influence. It is like a game of skill depending upon the compared with that part in the immediate wake of the eye, judgment and quickness in execution. Really few comet. The meteors may not, however, show a regular will excel, while many will only attain mediocrity, and decrease in numbers according to distance from their some must altogether fail to acquire the desirable derivative comet, but may probably consist of a series of proficiency, even after years of experience. groups. There is every reason to believe that disruptions The horary rate of appearance of Leonids cannot be of a violent character affect the physical character of exactly determined unless the contemporary showers are comets, and this was well exemplified in Brooks's comet considered, and their meteors separated from the true (I889 V.), visible, in I896, at its second observed return, Leon ids. Many observers count every meteor proceeding which was seen separated into five portions on August from the general direction of Leo as necessarily a Leonid, I, 1889. There is, however, every probability that the and thus the horary number is exaggerated. If an in• meteor cluster of I866 is some hundreds of times fainter experienced observer gives 20 as the number of Leonids than Tempel's comet; yet even the latter was not visible seen in an hour, the fair inference is that not more than to the naked eye in December 1865, or January I866, I 4 or I 5 of them were true members of that system. and indeed the object was only followed for a month in During very strong returns of the shower this point may, telescopes. It might be a good plan to endeavour to however, be disregarded, for the minor streams can then photograph the comet first, and then fish for its associated exercise very little relative influence on the results, and are meteor-stream ; for the easier objects are sometimes virtually obliterated by the superabundance of Leonids. capable of leading us up to the discovery of the more One new feature to be attempted during the ensuing difficult ones. W. F. DENNING. NO. 1461, VOL. 56]

© 1897 Nature Publishing Group