Formerly, but on the Other Hand the Weather-Observing Airplane Is
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formerly, but on the other hand the for safety in high-altitude cities like weather-observing airplane is rapidly Denver. At the meeting of the Amer- becoming one of the routine adjuncts ican Chemical Society here today, J. of meteorology. H. Eisemann, Dr. F. A. Smith and There is only one place in the world C. J. Merritt of the U. S. Bureau where similar records are obtained by of Standards reported on their ex- means of instruments attached to the periments on the changes needed in car of a mountain railroad.1 The gas appliances for safe operation at mountain in question is the Zugspitze, high altitudes. the highest peak in Germany, and the In general, they found that the car, suspended from an overhead maximum safe rate for the supply cable, travels a vertical distance of of gas at sea level, measured in heat nearly a mile in 16 minutes; several units consumed per hour, is reduced trips being made between the summit by approximately three to four per and the base of the mountain every cent for each thousand feet of alti- day. A set of instruments that make tude; but the number of cubic feet continuous records of barometric per hour of gas of given composition pressure, air temperature and humid- which can be burned completely is ity is fastened above the roof of the practically independent of altitude. car.—C. F. Talman in Why the The area of flue opening which will Weather? (SS). permit the flow of enough air to in- Gas stoves in mountain cities have sure complete combustion increases special air requirements. Gas stoves somewhat more rapidly than in pro- and other gas-burning appliances that portion to the altitude at each gas are safe and suitable for use in low rate, and this effect is the greater altitudes need to have their "settings" the higher the gas rate.—Science for gas and air flow set differently Service. FOG NOTES Fog, mist and haze.—Can you dis- seem clammy or humid, because the tinguish between fog, mist and haze? minute water drops are much too Even professional weathermen dis- small and scattered. Mist also often agree about the precise meanings of has a grayish color, and is thus dis- these terms. The International Me- tinguished from real fog. teorological Organization is now con- Haze. Dust particles from arid sidering the adoption of the following regions, or salt particles, which are definitions, proposed by the Norwe- dry and so extremely small that they gian meteorologist, T. Bergeron: can not be felt nor be discovered by Fog. Microscopically small water the eye, but which lend a character- drops, which apparently are sus- istic smoky (hazy and opalescent) pended in the atmosphere. Thus the aspect to the air. Haze lays a uni- air feels clammy and humid. On a form veil over the landscape and sub- closer examination one may even see dues its colors. This veil has a bluish the water drops floating past the eye. tinge when viewed against a dark As a whole the fog looks whitish, background (such as mountains), but except in the vicinity of industrial a dirty yellow or orange tinge against regions, where it gets a dirty yellow a bright one (such as clouds at the or gray color. In real fog, which is horizon, snowv summits or the sun)v not on the point of dissolving, the It is thus distinguished from the horizontal range of visibility is less grayish mist, the thickness of which than one kilometer, at least in one it may sometimes attain.—C. F. Tal- direction. man in Why the Weather? (SS). Mist. Thin fog or foggy air, in which the range of visibility is greater Details of Marconi's radio fog than one kilometer. The air does not beacon explained.—The working prin- 1However, Mr. H. H. Clayton obtained such ciples of the fog navigation radio records by carrying a meteorograph up and beacon device invented by Marchese down the Mt. Washington (N. H., 6284 feet) Guglielmo Marconi are now known. Cog Railroad several times during the sum- mer of 1907 and Mr. S. P. Fergusson did the Recent press reports of the invention same in September, 1934.—Ed. were so fragmentary that scientists Unauthenticated | Downloaded 09/29/21 04:17 PM UTC in England and America could not the compass. Whenever signals are determine the mode of operation and received bright green arrows appear weigh the system's value. behind the dial. The direction of each To picture the application of the arrow gives the bearing of the cor- radio transmission one may think in responding ship and its thickness in- analogy of twin searchlights on a dicates her distance. The approximate single mounting with a dark zone courses of the ships are deduced as between the two beams in the center, soon as subsequent signals are re- reports Commander E. C. Shankland ceived. If the arrow has become to the British scientific journal, Na- thicker the ship is approaching the ture. Each of the two radio beams, course of the ship receiving the sig- right and left, have distinctive char- nals, and if it steadily continues to acteristics. Using a sixty centimeter become thicker the receiving ship (two feet) long wave as the carrier must alter her course to avoid a col- signal, the right-hand beam sends out lision. A more exact determination signals varying 500 cycles a second. of the course can be obtained by the On earphones this frequencv sounds usual triangulation principle of navi- like a low-pitched note. The left-hand gators. If the system is internation- beam transmits a 1,500 cycle note, of ally adopted all fogbound ships will much higher pitch than its companion. send out every twenty seconds a signal By having the two notes in exactly consisting of a Morse "dot," the signal opposite phase a zone of silence, itself lasting only a thousandth of a where the two notes cancel out, is second, so as to reduce interference achieved in a central zone between to the minimum. The signals are them. This silent zone at a distance received on two fixed loop-aerials, of ten miles extends over 355 yards. mutually perpendicular, which are "To have such a signal fixed in posi- connected to electrically similar am- tion," Commander Shankland de- plifiers. The outputs from these clares, "would be unsatisfactory, as a amplifiers, at the original radio fre- navigator might assume he was in quency, are applied to the two pairs the silent zone when a breakdown of deflecting plates in a cathode-ray had occurred and the transmitter was oscillograph. The screen of the not functioning. To guide the ship oscillograph forms the indicating dial safely, therefore, the system is con- of the instrument.—Science Service. tinuously swung from left to right of London's dense fogs.—The world- the center line in a manner similar wide renown of London's fogs is to a searchlight when looking for an probably due, in a considerable meas- object on the water. When swinging ure, to the descriptions of them found to the left the beacon sounds a high in Dickens' novels, written between note, when swinging towards the right 1837 and 1870. It appears, however, it sounds a low note. The change that the same descriptions have of note takes place when the zone of created a somewhat exaggerated idea silence coincides with the line of the as to the frequency of dense fogs in entrance of the harbor."—Science the world's metropolis. Foggy weather Service. is very prevalent there in the cold season, but the fogs that turn day Cathode-ray direction finder would into night numbered only two or three prevent ships colliding in fog.—A a year, on an average, up to about new type of direction-finder, incor- 1830, so far as can be judged from porating a cathode-ray oscillograph, available records. From that time has been devisd by L. H. Bainbridge on the frequency of dense fogs gradu- Bell, of the Government Radio Re- ally increased. By the end of the search Station at Slough, Bucking- century the average was nine a year. hamshire. It shows the bearing, In recent times, owing to the partial course and approximate distance of substitution of gas and electricity for all large shipping within a distance raw coal in heating and cooking, the of ten miles, provided that the ships fogginess of London has shown a ten- are sending out the signals required dency to decrease. London's dense by the new system. The instrument fogs are commonest in November. has a dial marked with the points of During a period of 106 years there Unauthenticated | Downloaded 09/29/21 04:17 PM UTC were 125 of them in that month.—C. some remarkable clouds of steam sur- F. Talman in Why the Weather? rounding animals in intensely cold (SS). weather in northern Canada. In one case he saw "what resembled the Animal fogs.—In his book, "The smoke of a small brush fire from a North Pole," explorer Peary writes: band of half a dozen caribou a mile "When we started the thermometer away beyond a hill." Dr. Stefansson was minus 53 degrees, the minimum advanced the novel idea that enough during the night having been minus steam might be produced by animals 55; and when the twilight of evening in some cases to simulate an ordinary came on it was down to minus 59 ground fog about a village or town; . the dogs as they traveled were but this hardly seems plausible.