September 23, 1922] 



NA TURE 



4i5 



widened. It frequently happens that the portion at 

 middle heights is not visible, on account of the 

 relative dryness of the air. 



F. J. W. Whipple (Meteorological Magazine, Febru- 

 ary 1922), writing on cloud pendants, shows that 

 within a whirl of 20 metres diameter, rotating once 

 in a second, with a lowering of pressure of 30 mb. 

 at the centre, the maximum wind speed would be 

 70 metres per second, or 160 miles per hour, in agree- 

 ment with winds estimated in tornadoes. A de- 

 ficiency of 30 mb. pressure represents a suction suffi- 

 cient to support 1 foot of water only. The solid 

 appearance of a waterspout is therefore not to be 

 ascribed to the lifting up into the air of a solid column 

 of water, but is due partly to the condensation of 

 water vapour within the whirl itself, and partly to 

 water drops which are carried upward in spiral paths. 

 This upward motion of water drops is a well-marked 

 feature of most waterspouts. 



The existence of an outer sheath, separated from 

 the central core by a clear space, would appear to 

 require a discontinuity of water content of the air, 

 symmetrical about the axis of the whirl. It does not 

 appear possible to explain it even as the effect of 

 discontinuities of velocity within the whirl. No 

 physical explanation of this clear space can be sug- 



It is usually suggested in text-books (for example, 

 Humphreys's " Physics of the Air," p. 213) that 

 waterspouts are formed at the boundaries of wind 

 currents of different directions. But as such bound- 

 aries are of considerable extent, it is difficult to 

 understand why single waterspouts ever come into 

 existence. One would rather expect to find large 

 families of waterspouts distributed over a consider- 

 able area. It is true that usually several are seen at the 

 same time, but isolated cases are not infrequent. 



The fact that Dr. Hale Carpenter, while standing 

 within about one hundred yards of the waterspout 

 he describes, apparently felt no wind from the whirl, 

 testifies to the very limited diameter of the whirl in 

 question. D. Brunt. 



Meteorological Office, Air Ministry, 

 Sept. 1. 



Periodic Structure of Atoms and Elements. 



A. C. Crehore, in his recent papers on " The 

 Hydrogen Molecule " in the Philosophical Magazine 

 (October 1921, May 1922, and June 1922), makes use 

 of the specially constituted atoms of hydrogen and 

 helium discussed by him, and of a hypothetical atom, 

 the atomic weight of which is 2^, to build up some of 

 the other atoms. He uses H particles, hydrogen with 

 charge +e; a-particles, helium with charge +2e; and 

 particles of his hypothetical element, with positive 

 charge +e. I think it is clear that he recognises the 

 need for a helium particle with positive charge +e 

 in addition, if neutral atoms are to be built up in the 

 way he indicates. In one of his models one of the 

 particles marked 4 is also marked with a dot, and this 

 evidently means that it has a charge + e only. Calling 

 these particles 7, glucinum or beryllium becomes a, 

 7, H and its structure appears to be 7 a H. where 

 the hyphens indicate electrons. Its isotope, of atomic 

 weight 12, is -7-H-7-H..., forming a simple ring 

 of unit-charged particles. Nitrogen is 2a, 7, 2H, and 

 may have the structure 



/ H \ 



a a 



7 - 7 

 NO. 2760, VOL. I io] 



Fluorine, instead of having the constitution assigned 

 to it by Crehore, may be 2a, 27, 3H, and may have either 

 of the two following structures : 



-7-H-H- 

 ~°- 7-H 

 the o's joining up to form a ring, or 



_ 7 _H_r H n... 



-7-H- a 



the two 7's joining up to the a on the right to form 

 a ring. 



Starting from the element of lowest atomic weight 

 in each of the groups of the periodic table, I have 

 found it possible to build up all the other elements 

 of these groups, with atoms of distinctly similar 

 structure for each group, and marked differentiation 

 between the different groups. This has already been 

 carried out up to uranium for nearly all the groups, 

 so that hypothetical models, of the correct atomic 

 weight and atomic number, could now be constructed 

 for the majority, and probably for all, of the known 

 elements and their actual and probable isotopes. 

 Uranium (U.I.) has been assigned the structure 



-77- -77-H- 



= 150 15a a = 



-77- -77-H- 



forming a ring-shaped chain of thirty-one a-particles 

 joined up by two equal chains of 77 particles and 

 two other equal chains of 77 and one H particle. 

 This type of structure may be assigned to elements of 

 Group VI. H. Newman Allen. 



3 Lexham Gardens, Kensington, W.8, 

 Aug. 26. 



Transmission of Sound of Explosions. 



Readers of Nature may be interested to know 

 that a Commission appointed a year ago for investigat- 

 ing the transmission of sound of explosions is arranging 

 for an experiment on this subject to take place on a 

 day to be notified as soon after September 23 as the 

 weather will permit. 



On this occasion it is the War-Minister of the 

 Netherlands who has been able to assist the Com- 

 mission by notifying it of the intention to explode, 

 on the day to be appointed, some 10,000 kilogrammes 

 of perchlorate of ammonium at 19-30 (western 

 European time) ; the main explosion will be preceded 

 by a small explosion of a mass of 500 kilogrammes 

 at 19-25. 



I learn these particulars from Prof. Van Everdingen, 

 director of the Meteorological Service of the Nether- 

 lands, who tells me that the countries surrounding 

 the locus of explosion — Oldebroek, Lat. 52° 29' 56" N., 

 Long. 5 59' 40" E. — within 500 kilometres, are being in- 

 vited to instruct their observers to watch for evidence 

 of the explosion. 



Napier Shaw. 



Sept. 18. 



Research and Razors. 



The incident referred to by Principal Irvine 

 (Nature, Sept. 16, p. 385) mavhave been in connexion 

 with Faraday r 's w-ork on special steels. These were 

 not, I think, a success so far as their use for razors is 

 concerned, so that the present was appropriate. In 

 any case Faraday had little to complain of, since the 

 modern manufacturer does not send even razors. 

 J . R. Partington. 



45 Kensington Gardens Square, W.2. 

 Sept. 16. 



