June, 1911. 



KNOWLEDGE. 



225 



nebulous star, but it bears magnification well, and its annular 

 character can easily be made out with a moderately high 

 power. 



M SO (Scorpio). A compact globular cluster half way 

 between a and li Scorpii ; looks Ukc a nebula iu small 

 telescopes. 



QUERIES AND ANSWERS. 



Rcailcrs arc invited to send in Questions and to answer the Queries which arc printed here. 



UU ESTIONS. 



41. THE EFFECT OF RIGID RAILS ON THE 

 SPEED OF A TRAIN. — A pendulum shows that, as one 

 walks towards it, one makes a dimple in the ground. 



1 ha\e often observed the dimple which is made by a 

 running locomotive. 



As the engine is continually climbing out of consecutive 

 dimples, a question arises — is the speed of a train lessened 

 thereby, and would the train travel faster if the rails were 

 absolutely rigid ? Francis Ram. 



42. THE CARRI()N CROW.— Can any of your readers 

 inform me whether a clutch of nine crow's eggs has been 

 recorded ? I found a nest in the Hrent Valley this Spring 

 containing eight greenish-brown eggs and one greenish-grey. 

 The eight were at the bottom of the nest, and the other on 

 top of the others. Geoffrey Ker Webb. 



43. .\STRONOMY. — Of what value is " Urania's Mirror, 

 or a View of the Heavens" (published by Sleighl, consisting 

 of 32 coloured plates, engraved by Sid. Hall, sculptor '- 



A. M. F. 

 REPLIES. 



31. It has never come to my ears nor eyes that wireless 

 telegraphy did or would have anything to do with changes in 

 the weather, but to me it seems feasible and likely. 



The entire universe is built upon \ibrations, and electrical 

 forces and storms are no exception. If it is true that wireless 

 telegraphy may, in a measure, influence weather conditions, it 

 is because of the vibrations of the electric and air waves it 

 sends forth from the central station. Of course, the greater 

 the electricitv generated the greater the change in the weather. 

 I can go no further and state why these vibrations should 

 cause any change in the weather, hut will give a few examples 

 we have all seen or heard, 



A heavy peal of thunder during an electrical storm — one 

 that jars the house and shakes the windows — is. in almost all 

 cases, followed by a heavy downpour of rain. The terrible 

 convulsions of the atmosphere during tornadoes, frequent in 

 the southern states of the United States and the hurricanes of 

 the West Indies, are invariably followed by torrential rains. 

 Whirlwinds coming out of a clear sky are immediately followed 

 by clouds and storminess. The fair weather preceding an 

 earthquake is quickly changed, after the vibrations and tremors 

 of the earth, into cold, cloudy and rainy conditions. After all 

 great battles, where heavy cannonading has been going on for 

 any length of time, rain is sure to fall with the gathering of 

 clouds soon after. Even during the .American Independence 

 celebration, rain generally falls at night in the places where 

 the most fireworks have been set off, no matter how clear the 

 weather had been during the day. Allow me to go one step 

 farther and say that all the planets, as electric dynamos, are 

 sending forth vibrations throughout space which causes the 

 ocean tides and the varying storm and weather conditions 

 upon ours and other whirling globes, ^ j^^ Pritchard, 



39. ANTICYCLONE.— It is ijuite true that an anticyclone 

 is not always the opposite of a cyclone as regards the actual 

 strength of the wind, but there are certain properties of these 

 systems which make them diametrically opposed. (1) The 

 wind circulation is anti-clockwise in a cyclone, but clockwise 

 in an anticyclone, (21 Pressure is highest at the centre of an 

 anticyclone, but lowest at the centre of a cyclone; and, there- 

 fore (31 the wind circulates spirally outwards iu an anticyclone, 

 but spirally inwards in the case of a cyclone. (4) Comparatively 



speaking the calmest area of an anticyclone is at its centre, 

 whereas the windiest area of a cyclone is at its centre. Thus the 

 term "' anticyclone " does not always infer quiet weather. 

 There is sometimes a difficulty in that there is no hard and fast 

 boundary between the edge of an anticyclone and that of a 

 cyclone ; one canrtot always say how much of the wind's strength 

 is due to one system or the other. Thus the term " anti " is 

 justified in four respects, not to mention the fact that an 

 anticyclone usually drifts or remains stationary, whereas a 

 cyclone generally has a much faster motion in a certain 



'^'^^'^''°"- ' C, H. E. R[(M.ATH. 



40. WATER- FIN DING. —No scientific explanation is 

 yet attainable. The supposition of those who have most 

 thoroughly studied the phenomena is that some people can 

 sub-consciously perceive underground water, and so on. by a 

 kind of sixth sense, and that the sub-consciousness signals its 

 discovery by twitching the muscles and thus moving the rod. 

 The only scientific treatment of the subject at any length is 

 in Professor W. F. Barrett's reports in the " Proceedings " of 

 the Society for Psychical Research, Vols. 13 and 15. A 

 condensation is given in his pamphlet " On the Hi'story and 

 Mystery of the so-called Dowsing or Divining Rod," obtainable 

 for Is., from the Secretary. Society for Psychical Research. 

 20. Hanover Square, London, W, 



J, Arthi'r H[li., 



5S. H.ALLEY'S COMET. — "Interested" asks a question 

 with reference to the determination of the distance of Halley's 

 Comet from the Sun, and also its velocity, at any time, say 

 two >ears after passing Perihelion, .April 19th, 1912. 



The following easy method can be used, when the pertur- 

 bations of the planets are not taken into consideration. 



Let the figure represent the path of the Comet in its orbit, 

 where A.-^' is the axis major of the ellipse described, S the Sun 

 in one of the foci of the ellipse, C the centre, and M the 

 Comet two years after passing perihelion. Of course A will 

 represent perihelion point. 



We assume the following data in connection with Halley 

 Comet : — 



... 76 



Periodic time 

 Perihelion distance 

 Eccentricity ... 

 Aphelion distance 



35 



37 years. 



5889 Astronomical Units. 



967 



411 .Astronomical Units 



the radius \ector is called the 



The angle ASM described b\- 

 " True Anomaly," and is generally denoted by v ; the angle 

 described by the radius vector on the assumption that it 

 moves uniformly, is called the " Mean .Anomaly " : it is usual 

 to denote it by M. Now, if we suppose a circle circumscribed 



