88 



NATURE 



[March 17, 192 1 



the machine was shut down. Examination showed 

 that one of the insulated bolts through the core had 

 broken down near the end plate. These bolts pass 

 through the core in an axial direction and serve to 

 hold the end plates tightly against the laminations. 

 Inspection of the bolts showed that vibration of a 

 more or less serious nature had occurred on several 

 of them. A series of tests revealed the fact that for 

 the particular length and diameter of bolt used a 

 relatively sHght tension was sufficient to bring the 

 frequency of the bolts to such a value as to synchronise 

 with the frequency of the whole set, corresponding 

 to the speed of 1500 r.p.m. Re-inspection of the first 

 machine indicated that breakdown was due to the 

 same trouble. A third machine with bolts of a 

 modified design has been running- since the end of 

 December and has carried peak loads of 21,000 kw. 

 The new type of bolt has a natural frequency very 

 far below the running frequency of the machine. 



In the notice of a volume on "The Control of 

 Parenthood " which appeared in Nature for March 3 

 (pp. 5-6), the reviewer remarked that " Dr. Mary 

 Scharlieb, the doctor of medicine, differs in emphatic 

 terms from Dr. Marie Stopes, the doctor of science 

 and philosophy." Dr. Stopes has written to express 

 the opinion that these words will give readers the 



impression that Dr. Mary Scharlieb's "antagonism to 

 birth-control methods is based on medically deter- 

 mined detrimental effects of specified methods," 

 whereas she holds that " under cover of the title of 

 doctor of medicine Dr. Mary Scharlieb voices a 

 religious conviction." We would prefer not to devote 

 space to the difference between these points of view, 

 but among the passages upon which our reviewer 

 founded his statement is one on pp. 105-6 of the 

 book noticed, and we refer Dr. Stopes to this in 

 justification of his remark. But surely she is hasty 

 in thinking that readers of Nature will read into the 

 meaning of the sentence solely the medical aspects of 

 the subject (which she claims were not decided by the 

 evidence before the Commission). Is it not much 

 more likely that some readers will, as is their wont, 

 see less and some more than the words justify, whilst 

 others will see simply the literal meaning? 



Students of India and the Far East should be 

 interested in the latest catalogue (No. 411) of Mr. F. 

 Edwards, 83 High Street, Marylebone, W.i, which 

 gives particulars of some 1133 books, engravings, and 

 drawings relating to India, Afghanistan, Ceylon, 

 Burma, Tibet, Central Asia, Persia, etc. The cata- 

 logue will be sent free by the publisher vipon 

 request. 



Our Astronomical Column. 



The Fireball of March 2. — Mr. W. F. Denning 

 writes that further observations of this meteor have 

 been received from Mr. Thomas Dick, of Purley, 

 Surrey, Mr. G. Merton, of Woldingham, Surrey, and 

 an observer in Hertfordshire. Mr. Merton did not 

 observe the fireball in flight, but noticed the illumina- 

 tion it caused. He was about to oljserve a star in 

 his telescope when the whole inside of the observatory 

 was lit up for a few seconds, and he rightly concluded 

 that a large meteor had fallen. From a comparison 

 of all the observations it appears that the radiant 

 point was at about i76°+24°, and that the height 

 of the meteor declined from 77 to 34 miles along a 

 path of 61 miles, traversed at a velocity of 20 miles 

 per second. Further observations of an exact 

 character of the apparent course of the meteor 

 amongst the stars would be valuable. It is to be 

 hoped that in future years special attention will be 

 given by meteoric observers to the first few nights of 

 March, for past experiences amply testify to a special 

 abundance of fireballs at this period. 



The Rotation of Venus. — The problem of the rota- 

 tion period of our nearest planetary neighbour has 

 proved to be one of the most baffling of astronomical 

 enigmas. Before Schiaparelli's announcement that 

 it always turned one face to the sun, its period was 

 supposed to differ little from that of the earth. Since 

 then astronomers have been fairly equally divided 

 between supporters of the short and of the long 

 period. 



In the last few weeks Prof. W. H. Pickering, 

 who has been observing the planet in the clear and 

 steady air of Mandeville, Jamaica, has put forward 

 a new solution. He claims to have fixed the period 

 as sixty-eight hours, the axis of rotation lying very 

 nearly in the plane of the orbit, with which it makes 

 an angle of only 4° or 5°. Such a bizarre arrangement 

 does not strike one as probable a priori, in view of 

 NO. 2681, VOL. 107] 



the considerable tides which the sun raises on the 

 planet. It prevails in the Uranian system, but the 

 solar tides there are much feebler, since, ceteris pari- 

 bus, they vary as the inverse cube of the distance 

 from the tide-raising body. However, when Prof. 

 Pickering's full evidence for his new period arrives it 

 will be carefully studied, and will doubtless stimulate 

 other observers to use their best endeavours to 

 verify it. 



A Simplified Calendar Reform. — In view of thr 

 difficulty of obtaining agreement on the vexed subject 

 of calendar reform, the Rev. Emilio Fanfani, of Pavia, 

 has published a pamphlet in which he reduces the 

 proposed change to a minimum. His suggestion is to 

 leave the lengths of the months the same as at pre- 

 sent, but to put January i, and in leap year February 

 29 also, outside the weekly reckoning, calling them 

 simply New Year's Day and Leap Day. Thus the 

 week-davs would recur annually on the same calendar 

 dates. The author further recommends that the 

 present year 192 1 should be taken as the standard, 

 since Christmas occurs on a Sunday. Thus January 

 I, 1922, would be New Year's Day and January 2 

 Sunday, as in 192 1. He further recommends the 

 fixing of Easter on April 10, though this is not an 

 essential part of his scheme. 



This plan has the recommendation that the cal- 

 culated dates of future astronomical events are un- 

 affected, and no alteration of astronomical tables is 

 involved. While it does not do all that calendar 

 reformers desire, it is at least better than nothing, and 

 would be a boon in fixing school terms, commercial 

 transactions, the meeting of societies, etc. 



Prof. Pio Emanuelli, of the Vatican Observatory, 

 contributes a preface, in which he commends the 

 project to the Commission on Calendar Reform 

 constituted bv the International Astronomical 

 Union. 



