54 



NA TURE 



\_Nov. 19, 1885 



somewhat less in using a photographic Ihcoilolite than in using 

 our instruments. But on the other hand our method enables us 

 to ciliserve the clouds even in twilight and moonlight, in rain 

 and storm. Also, it is, no doubt, much cheaper tlian the photo- 

 graphic one. N. Ekhoi.m 

 Up ala, November 6 



The Helm Wind 



Some years ago I passed a summer at Melmerby, which is 

 -about the best place for seeing the " helm,'' which is incorrectly 

 described as affecting the Penrith valley (for, in fact, it never 

 c\lcnds to Penrith) by your correspondent, M. WoeikofF. 



Melmerby is at the foot of the Cross Fell range, and gets the 

 " helm " with great violence. When an easterly wind co.iies 

 on, the summit of Cross Fell becomes clouded ; it puts 011 its 

 I dm : then from this a violent cold wind pours down the hill- 

 side (which is steep) and rises up again at no great distance. 

 At Melmerby, and places similarly situated, there is clear sky, 

 for the moisture in the sky is invisible, but further from the 

 range it is precipitated where the current rises, and there is 

 cloudy sky, without the strong wind. The phenomenon is, in 

 fact, precisely that at Table Mountain, where the cloud on the 

 crest IS called the " table-cloth." 



Judging from M. Woeikoff's description there seems to be a 

 difference in the phenomena. Probably owing to the ^eullt: 

 ilopes of the Varada chain the air does not seem to rise again, 

 and there is no cloud-lwnk parallel to the chain. It would 

 seem, too, that the wind extends to the i;v.iY, unless there is a 

 misprint. J. F. Tennant 



37, Hamihon Road, Ealing, W., November 13 



THE MODE OF ADMISSION hVTO THE 

 ROYAL SOCIETY 



OUR conlenipornry Science, in the last number whic 

 has reached this country, makes some remark, 

 concerning the admission of candidates into the Royal 

 Society, against which, in the interests of truth and 

 accuracy, it is our duty to protest, the more especially as 

 it is also implied that the French system of canvassing 

 those who are already Fellows of the Society is also 

 adopted. 



The statements actually made are (i) that there is an 

 "actual competitive examination, on the result of which 

 a certain number of successful candidates are annually 

 chosen," and (2) " that the English method has the addi- 

 tional disadvantage that it does not secure the men 

 whom it is most desirable to honour." We read also, 

 " During the schoolboy period the distinction between 

 different individuals is a distinction of learning, and an 

 examination is not unfitted to discover the boy who 

 deserves reward. But learning is not the quality which 

 a State needs to make it great. Casaubons are not the 

 kind of men who have built up English science. The 

 qualities which ought to be encouraged, and which it 

 should be a nation's delight to honour are qualities too 

 subtle to be detected by a competitive examination." 



For the benefit of our transatlantic brethren we may 

 as well state the facts as we know them. For reasons 

 into which we need not enter here, as they do not aiTcct 

 the question at issue, nearly forty years ago the Royal 

 Society determined to limit the yearly admissions to 

 fifteen ; and to throw upon the Council the responsibility 

 of selecting the fifteen who are to be nominated for elec- 

 tion, a general meeting of the Society reserving to itself 

 the right of confirming or rejecting such nomination. It 

 may be instructive to remark that for thirty years that 

 right has not been exercised. 



The way in which the matter is worked is as follows : — 

 The friends of a man, who are already in the Society, 

 and who think he is entitled to the coveted distinction, 

 prepare a statement of his services to science, in 

 many cases without consulting him in any way. This 

 paper thus prepared is sent round to other Fellows of the 

 Society, who are acquainted with the work of the candi- 



date, and who sign it as a testimony that they think he 

 is worthy of election. In this way when the proper time 

 arrives some fifty or sixty papers are sent in to the 

 Council for their consideration. In the Council itself we 

 may assume that the selection of the fifteen is made as 

 carefully as possible in view not merely of individual claims 

 but of the due representation of the different branches 

 of science. It is not for us to state the safeguards or 

 mode of procedure adopted, but we think we may say 

 that the slightest action or appeal to any member by the 

 candidate himself would be absolutely fatal to his election. 

 Finally, we may say that, years back, when a heavy 

 entrance fee had to be paid, there were cases in which the 

 question had to be put to one whose friends were anxious 

 to see him elected, whether he would accept election. 

 The small yearly subscription of 3/., now the only sum 

 payable, makes even this question unnecessary at the 

 present time. 



ON MEASURLYG THE VIBRATORY PERIODS 



OF TUNING-FORKS 

 nPHE tuning-fork when its nutnber of double vibrations, 

 ■'■ to and fro, in a second, or briefly its frequency, has 

 been ascertained, is a most convenient instrument for 

 measuring minute divisions of time. As such it is now 

 extensively used for phj'sical, physiological, and military 

 purposes (velocity of bullets and cannon balls). The 

 antecedent difficulty of ascertaining the frequency, is 

 however very great. The old processes, sufficient for 

 roughly ascertaining musical pitch, and dependmg upon 

 wires of known weight, length, and tension, or the action 

 of the siren, are totally insufficient for modern purposes. 

 It was the contradictory nature of the results furnished 

 by the monochord in the division of the Octave into 

 twelve equal parts that led Scheibler to his system of a 

 series of tuning-forks diflering from one another by known 

 numbers of vibrations, leading to countable beats, and 

 extending over an Octave. Nothing can be more con- 

 venient to use than such a series of forks for all musical 

 purposes. They enable the frequency not only of any 

 small as well as large tuning-fork, but also of any sus- 

 tained tone to be ascertained w-ithin one-tenth of a vibra- 

 tion, that is, one vibration in ten seconds. The writer 

 has for some years been in the constant habit of using 

 such a set of forks with the most satisfactory results. His 

 own forks were measured by Scheibler's (exhibited in the 

 Historic Loan Collection of Musical Instruments at the 

 Albert Hall this year), but extend over a greater range, 

 from about 224 to about 5SS vib., that is, rather more 

 than an Cctave and a major Third. The great advantage 

 of such a tonometer is extreme portability, immediate 

 application to any sustained tone (even that of a pianoforte 

 string), and the independence of the result from any 

 (almost always imperfect) estimation of unison by a 

 musical ear. There are of course antecedent difficulties 

 in ascertaining the pitch of each particular fork, but these 

 are overcome by patient observation, the extension of the 

 series beyond an Octave furnishing in itself the required 

 check. 



Scheibler died in 1S37. In 1879 Prof. Herbert MacLeod 

 and Lieut. R. G. Clarke, R.E. {Ptoc. R. Soc, vol. xxviii. 

 p. 291, and Philosoph. Trans., vol. clxxi. p. l) invented 

 an optical arrangement, which under proper management 

 (but the manipulation w-as very difficult) gave excellent 

 results for large tuning-forks, like those of Koenig. And 

 in 18S0 Koenig {Wiedemann's Annalen, 1880, pp. 394- 

 417) invented a clock method for ascertaining with 

 extreme accuracy the frequency of one large standard fork 

 of 64 vib. at 20" C. Before both Prof. .MacLeod and Dr. 

 Koenig, Prof. Alfred Mayer, of Hobokcn, New Jersey, 

 U.S., had invented a most careful and ingenious electro- 

 graphic method, of which a full account has just appeared 

 in vol. iii. ofthe Transactions ol the National Academy 



