252 



DISCOVERY 



SCIENCE AND MEDICINE 



Textile Chemistry : An Introduction to the Chemistry of 

 the Cotton Industry. By F. J. Cooper. (Methuen 

 & Co.. Ltd., los. 6d.} 



Atomic Structure and Spectral Lines. By Arnold Som- 

 MERFIELD. Translated by Henry L. Brose. 

 (Methuen & Co., Ltd., 325.) 



Studies in Fossil Botany. Part II. Third edition. 

 By DuKiNFiELD Henry Scott, M.A., IX.D., D.Sc, 

 F.R.S., F.L.S., F.G.S., F.R.M.S. (Adam & Charles 

 Black, 215.) 



Practical Plant Ecology. A Guide for Beginners in Field 

 Study of Plant Communities. By A. G. Tansley, 

 M.A., F.R.S. (George Allen & Unwin, Ltd., 7s. 6rf.) 



Elementary Zoology. By Oswald H. Latter. (Methuen 

 & Co., Ltd., I2S.) 



Plant and Flower Forms. By Esther J. G. Kirkwood. 

 (Sidgwick & Jackson). 



Relativity and Modern Physics. By George David 

 BiRKHOFF, Ph.D. (Harvard University Press; Hum- 

 phrey Milford, Oxford University Press.) 



Vector Analysis. By C. Runge. Translated by H. 

 Levy. (Methuen & Co., Ltd., gs.) 



Foundations of Biology. By Professor Lorande Loss 

 Woodruff. (Macmillan, 165.) 



Chance and Error. By Marsh Hopkins, B.A.Sc, 

 M.E.I.C, D.L.S. (Kegan Paul, 7s. bd.) 



The Antiquity of Disease. By Roy L. Moodie. (Univer- 

 sity of Chicago Press, Si. 50.) 



Elementary Hygiene. By Bihara Lal Bih.\tra and 

 Prem Nath Suri. (Longmans, Green &. Co., zs. 6d.) 



Correspondence 



the crater " Flammarion," 235,000 miles from the earth's 

 surface. The moon is 2,000 miles in diameter, so that the 



J h 



Sir, 



AXIAL ROTATION 

 To the Editor of Discovery 



Please be good enough to allow me space to reply 

 to Mr. Sillem's letter in your July issue in which be is 

 attempting to help me in my perplexity concerning the 

 moon's movements. I regret to inform him that I am 

 not yet " out of the wood." I was staggered when he 

 told me that the disk on the second's hand of my watch, 

 the ball on the string, the orange near the circumference 

 of the turntable, were each turning upon their own axes. 



He has not, however, said anything about the spinning- 

 top or the bicycle pedal. 



In his diagram (which perhaps you will be good enough 

 to reproduce here) he represents the moon in the position 

 it would' occupy if not rotating. 



It will be noticed, however, that this is an exact 

 representation of the pedal action, viz. forward revolution 

 and backward rotation, both movements synclxronising. 

 This, I think, is where the theory of rotation breaks down. 

 because lines in the pedal (picture it as a ball) do not 

 change their direction. But if the pedal makes the 

 merest fraction more, or the merest fraction less, than one 

 rotation each revolution then lines would change their 

 direction. So you see the rotation does not count, but 

 loooi does. In the diagram at lA we will suppose is 



crater at 3A is 237,000 miles from the earth's surface. 

 It has travelled in a semicircle from 1,000 miles inside 

 the moon's orbit (a thin line 236,000 miles from the earth) 

 to a 1,000 miles outside around what ? Surely the 

 moon's axis. London does this trick daily, and we 

 call it axial rotation. If it ceased to do it, what then ? 



I am, sir, yours, etc., 

 2, Heath Villa, J. Marshall. 



Birchwood Drive, 

 Leigh-on-Sea. 

 July 7, 1923. 



[This correspondence must cease. — Ed.] 



SUSPENDED ANIMATION 

 To the Editor of Discovery 

 Dear Sir, 



In connection with the alleged finding of frogs 

 embedded in the ground, which is the subject of a letter 

 in the August number of Discovery, the following extract 

 may be of interest : 



" At his advice, we sank the well, and at a depth of 14 

 feet came on water in marly rock. . . . One of the curious 

 things in sinking the well was, at a depth of 12 feet we 

 came across several green frogs in the marl, and as soon 

 as they were exposed to the air they turned black and 

 died." 



The letter, from which the above is taken, was addressed 

 by Mr. Codrington Crawshay, J. P., of Abergavenny, to 

 Professor (now Sir William) Barrett, on May 25, 1897. 

 It may be found in the Proceedings of the Society for 

 Psychical Research (Part ^2, vol. xiii, July 1897, p. 151). 



Yours, etc., 



Brian J. McCafferv. 

 College of Science, 



Dublin, 

 August I, 1923. 



