t>J2 



NATURE 



[October 27. 1923 



formal ; but it would appear that he did not revise, 

 as we understand the term, but merely read the 

 manuscript, plarinp also at the service of the author 

 certain tljs< ' ' xms for possible inclusion. The 



footnote is I i;. Thk Reviewer. 



Numerical Relations between Fundamental 

 Constants. 



In connexion with the letter from Dr. Ernest 

 Dorsey in Nature of October 6, p. 505, it may be 

 pointed out that most of the numerical relations 

 which he describes are implied in the statement given 

 in a paper in the Proceedmgs of the Physical Society 

 of Loncfon (vol. 27, p. 425, 1915), that all units derived 

 from e, m, and c can be expressed (with considerable 

 accuracy^ in (he C.G.S. system in terms of simple 

 integers \i, },. i)r 4), powers of 10, q and ir. Here q 

 is a pure number, which represents the value of 

 2re*lhc. Thi.s constant is the same as that employed 

 in Sommerfeld's papers on the fine structure of 

 spectrum lines, where it is denoted by o. If the 

 relation of Lewis and Adams (Phys. Rev. vol. 3, p. 92, 

 1914) be accepted, the numerical value of 9 or a is 

 (i5M*/(4'^)"= 7-28077 X io-». 



Whether this be the correct value or not, the 

 number represents one of the most important physical 

 constants, and corresponds to a deep-seated relation 

 between the ultimate nature of electric force and that 

 of magnetic force. The quantum theory indicates the 

 existence of discrete magnetic tubes of induction 

 determined by the fundamental unit {h/e), and it has 

 been suggested to me by Mr. W. H. Watson, of the 

 University of Edinburgh, that the constant may be 

 interpreted as giving the relation between a quantum 

 magnetic tube and a unit electrostatic tube of force. 



As regards the occurrence of integral powers of 10 

 in the expressions for physical constants, it must be 

 remembered that the units of length, mass, and time 

 in the C.G.S. system are not entirely arbitrary. The 

 assumption is made that the gram is the mass of 

 I c.c. of water at the temperature at which its 

 density is a maximum, and the fact that the " mole- 

 cular number" (Trans. Chem. Soc. vol. 113, p. 389, 

 1 91 8) of water is 10 possibly accounts for the rela- 

 tions concerned. Dr. Dorsey includes the gas 

 constant in his list, and here again the physical 

 properties of water are involved through the delinition 

 of tne Centigrade scale of temperature. 



H. S. Allen. 



The University, St. Andrews. 



Insects in Korean Amber. 



On the morning of September i I saw a piece of 

 caived amber, containing Diptera of several species, 

 in the shop of G. M. T. De Silva in Yokohama. I 

 was informed that it came from Korea (Chosen), but 

 as the exact locality and geological horizon were 

 unknown, and the price was rather high, I did not 

 purchase it. At noon of the same day the earthquake 

 occurred, resulting in the destruction of the whole of 

 Yokohama, including De Silva 's shop. I should 

 be greatly interested to learn anything more about 

 this Korean amber, the insects in which should be 

 described. Some days earlier I saw in Mr. Y. 

 Nawa's museum at Gifu a very fine lot of fossil 

 insects, apparently of late Tertiary age. These have 

 never been critically studied or described, but it is 

 to be hoped that they will eventually be properly 

 recorded. I could not discuss them with Mr. Nawa, 

 as he knows no English, and no interpreter could be 

 found at the time of my visit. 



T. D. A. COCKERELL. 



University of Colorado, Boulder, Colorado. 

 NO. 2817, VOL. I 12] 



Tidal DlMlpatton of EiMrgy.- 



Iv g denote the intensity of surface gravity, ^ the 

 density of water, and h the elevation of tli<- w;it«r 

 surface above its mean position, the potei v 



of the oceanic tide Ls J/fA* per unit area. 1 

 energy must be comparable. If h has the wjuii: 

 amplitude of 35 cm., the total energy of thf 

 the area of which is 3*7 x 10" cm.*, mus' 

 2 '2 X lo** ergs. 



Now the mean rate of dissipation of energy by 

 tidal friction is about 14 x 10'* ergs sec. Thus the 

 whole energy of the tides would t)e dissipated in ' 

 l'6x 10' sec., or two days, if dissipation con- 

 at its average rate and no new en- 



It follows that tidal friction n 

 absorb so much of the energy in i... ;...,i, ».. . 

 reach these seas, that the lags of the tides in tli 

 ocean may differ by some hours from those caL„...u . 

 on the usual assumption that the coasts may be 

 treated as simple reflecting boundaries. 



Harold Jeffreys. 



St. John's College. Cambridge. 



Repellents of Clothes Moths. 



In Nature of September 8, p. 376, appears a ret)ort 

 of a lecture on " Plants in Relation to the Healtn of 

 Man," in which Dr. A. W. Hill refers to the supposed 

 property of camphor as a preservative of clothing 

 agamst moth. Henri Fabre found camphor and 

 naphthalene to have no effect upon moths, and I 

 have found these insects utterly mdifferent to such 

 odoriferous substances. In fact, I doubt if they can 

 smell at all. It would be interesting to hear of some 

 definite experimental result bearing upon tliis point. 

 Reginald G. Johnston. 



51 Belmont Hill, London, S.E.13. 



Somewhat surprisingly, no precise experiments 

 with the object of discovering effective repellents of 

 clothes moths, of which at least three distinct species 

 occur in this country, appear to have been carried 

 out by any one. Mr. R. G. Johnston is p>erfectly 

 correct in regarding as devoid of any real foundation 

 the popular belief in the efficacy of camphor as a 

 preservative of clothing against moth, although there 

 is no reason for supposing the insects in question to 

 be deficient in olfactory sense. Naphthalene again, 

 if merely scattered loosely in a drawer or wardrobe 

 containing clothes, will certainly afford no protection 

 whatever. On the other hand, naphthalene is quite 

 satisfactory as a repellent if placed inside clothing 

 which is afforded the additional protection of a wrap- 

 ping of stout paper, the edges of which freely overlap, 

 and are tightly secured by means of pins. E. E. A. 



Amanita muscaria on Hampstead Heath. 



The difficulty of obtaining a supply of this mush- 

 room for scientific investigation is well known to 

 physiologists and chemists. Its disappearance, except 

 in unfrequented woods, is probably accounted for by 

 its attractive colouring and its subsequent destruc- 

 tion as one of the most poisonous representatives of 

 its family. Therefore its occurrence near London 

 deserves to be put on record. A fine specimen, 

 weighing 140 gm. and measuring 12 cm. in diameter, 

 was brought to me for identification by Mr. H. C. 

 Simmons, who found it, after the heavy rains of last 

 week, on the West Heath in the low-lying ground 

 between the North End and Spaniard's Roads. 



O. Rosenheim. 



75 Hampstead Way, London, N.W.ii, 

 October 17. 



