November 12, 1908J 



NA TURE 



47 



symbolically nailed to the figure, with certain offerings 

 of propitiation, before the latter is flung into the sea, in 

 ©rder to free the islands from its presence. The theory 

 that spirits can be shut up in jars or figures is familiar 

 in the tale of the Jinnee in the "Arabian Nights," and 

 is accepted by savages and semi-savages in many parts 

 of the world. 



OwiNO to the enormous reduction in the price of 

 aluminium which has recently taken place, it seems quite 

 likely that this metal will be largely employed instead of 

 copper in many instances, for example, as a conductor, 

 and it is also probable that it will be used in place of tin. 

 At one time it was a difficult matter to roll out very fine 

 sheets of aluminium, but further experience has enabled 

 the manufacturers to roll sheets even finer than that of 

 the ordinary tin foil. Aluminium rolled out in this manner 

 will probably in the near future replace tin foil for a great 

 many purposes, for example, the covering of chocolates 

 and food-stufTs, also for wrapping up materials for keep- 

 ing out damp. Tin is, at the present, about double the 

 price of aluminium, and it has, furthermore, to be borne 

 in mind that the specific weight is about one-eighth that 

 of tin, consequently, weight for weight, it is possible to 

 roll out eight times the number of sheets from aluminium 

 to what could be obtained from tin. Tin salts are more 

 or less poisonous, whereas aluminium salts, at any rate 

 in small quantities, are practically harmless, so that 

 children eating sweetmeats from which they have not 

 taken the trouble to remove the tin foil might do them- 

 selves considerable harm, but if aluminium were substi- 

 tuted for tin the chances of doing themselves ill would be 

 far less. 



The relatively high electrical resistivities of alloys as 

 compared with the resistivities of their constituents has 

 been attributed in succession by Lorenz, Ostwald, Ray- 

 leigh, and Liebenow to the thermoelectric effects produced 

 by the passage of the current through minute layers of 

 the constituents of the alloy arranged in series with each 

 other. Herr E. L. Lederer, of the University of Prague, 

 has determined the resistances of wires of a number of 

 alloys by the bridge method and by measuring the heat 

 developed in the wires by means of a calorimeter. His 

 results are given in the February number of the Si(s»H,ij5- 

 bcrichte of the .\cademy of Science of Vienna, and the 

 resistances determined by the two methods appear to agree 

 to within less than i per cent. Herr Lederer concludes 

 that the thermoelectric theory of resistivity of alloys is 

 therefore untenable. 



In our account of the " Mathematics and Physics at the 

 British Association," Prof. Lamb is credited with saying 

 (Nature, November 5, p. 24) : — " The daily variation of 

 temperature is not harmonic, and when it is analysed 

 there is a definite component with a half-day period. The 

 objection to attributing the semi-diurnal pressure variation 

 to this is that the latter is extremely regular, while the 

 temperature variation changes considerably with the 

 locality." Prof. Lamb writes to us to explain that this 

 contains a passage which conveys a rather different mean- 

 ing from what he (at any rate) intended to say. He does 

 not think there is any valid objection to attributing the 

 semi-diurnal pressure variation to the semi-diurnal com- 

 ponent of temperature vibration on the above-stated ground. 

 " A forced oscillation whose amplitude is exaggerated 

 owing to the near coincidence of its period with a free 

 period has necessarily all the simplicity and regularity of 

 the corresponding free mode." We are glad to have the 



NO. 2037, VOL. 79] 



opportunity of correcting our report in accordance with 

 this communication. 



Although the study of the refractive indices of gases 

 may be expected to lead to theoretical conclusions of great 

 importance, no very definite conclusions have been drawn 

 until recently from the existing experimental data. This 

 is partly due to the delicacy of the physical measurements 

 involved, but chiefly owing to the difficulty of obtainiirg 

 the gases in a pure state. The first regularity in the re- 

 fractivities of a series of chemical gaseous elements was 

 pointed out by Mr. C. Cuthbertson in connection with 

 the argon group, and in the current number of Science 

 Progress he gives a clear and interesting risumi of the 

 present state of knowledge as regards gaseous refractive 

 indices. The refractivities of the five gases helium, neon, 

 argon, krypton, and xenon are found to be almost exactly 

 in the ratios of i, 2, 8, 12, and 20, and Mr. Cuthbertson 

 has detected a similar set of ratios in other chemical 

 groups, notably in the halogen and oxygen groups. There 

 can be no doubt that the discovery of the cause of this 

 simple numerical relation will throw light on the struc- 

 ture of the atoms. As is pointed out in the article, there 

 is still room for much experimental work, some of it of 

 a high order of difficulty, before the true meaning of 

 these remarkable relations can be elucidated. 



Messrs. George Routledge and Sons, Ltd., have pub- 

 lished a second edition of " The Case for the Goat, with 

 the Practical Experience of Twenty-five Experts," edited 

 by " Home Counties." This edition includes some new 

 data on goat-keeping and new illustrations, while the 

 opportunity has been taken to make various emendations. 



We have received from Messrs. E. and F. N. Spon a 

 copy of the second edition of Mr. C. J. Woodward's 

 "ABC Five-figure Logarithms for General Use." In 

 this edition an index has been given on the inside pages 

 of the cover to find the page on which a given logarithm 

 of an arc function will be found, and a table of natural 

 arc functions to each minute of arc to four places of 

 decimals has been added. The price of the volume is 35. 

 net. 



The fourth part of the first volume of Proceedings of 

 the Association of Economic Biologists, that for September, 

 igoS, is now available. It is chiefly devoted to the papers 

 read at the meeting of the association held in London on 

 April 15 of this year, and reported in our issue of April 23. 

 The number also contains a summary of a meeting held 

 on July 4, and the annual report. 



A series of excellently produced catalogues has been 

 received from Messrs. Ross, Ltd., of New Bond Street 

 and Cockspur Street, London. Catalogue No. i deals with 

 photographic lenses ; field, studio, and hand cameras ; 

 lanterns, and the numerous miscellaneous accessories re- 

 quired by the photographer. The price of this catalogue 

 is one shilling. A second booklet is entitled " Aids to 

 Vision for Naval and Military Officers, Sportsmen, 

 Naturalists, &c.," and is devoted to descriptions, with 

 prices, of such instruments as prism binoculars, field 

 glasses, telescopes, sextants, magnetic compasses, baro- 

 graphs, and barometers. The remaining pamphlet, called 

 the " Ross Bird-stalker," is a report by Mr. Charles Dixon 

 on the advantages, possibilities, and uses of the Ross 

 prism binocular, as applied to field natural history. All 

 the catalogues include, in addition to the more usuat 

 illustrations of instruments, numerous beautiful process 

 pictures of objects and scenes reproduced from photo- 

 graphs. 



