684 



NATURE 



[February i8, 19 15 



December last the chairman, Prof. A. D. Cole, of 

 the Ohio State University, after reviewing the evi- 

 dence for the existence of the electronic atom with a 

 central nucleus, expressed the opinion that some such 

 form of atom would soon receive general recognition. 

 He does not, however, think that the details of any 

 of the atomic models at present under discussion can 

 be considered as more than tentative and provisional. 

 The address is reproduced in Science for January 15, 

 and gives a clear and readable account of the ad- 

 vances made during the past three years. 



The risum^ of communications made to the French 

 Physical Society at the meeting on January 15 in- 

 cludes a short account of the automatic apparatus 

 devised by M. E. L. Dupuy for the stud}' of the 

 anomalies in the expansion ' of alloys with rise of 

 temperature. The nature of these anomalies makes 

 it desirable that a continuous record of the expansion 

 should be obtained, and M. Dupuy has succeeded by 

 means of his apparatus in obtaining records for a 

 number of chrome-nickel steels which go far towards 

 clearing the way for a complete explanation of their 

 behaviour. The new apparatus requires a rod about 

 7 cm. long of the material to be tested, and a similar 

 rod of silica. The two support a mirror which rotates 

 about a horizontal axis as the lengths of the two 

 rods become different during the expansion. A beam 

 of light after reflection at this mirror falls on a 

 second, which is rotated about a vertical axis as the 

 current from a thermo-junction in contact with the 

 specimen varies. The beam of light is received finally 

 on a photographic plate, and a curve results the 

 abscissae of which are temperatures and ordinates 

 expansions. 



In a paper entitled "Alchemy and the Devil," by 

 Dr. J. B. Craven, Archdeacon of Orkney, read before 

 the Alchemical Society on February 12, attention was 

 directed to the close association which existed in the 

 eyes both of the Church and the people between 

 alchemy and magic, and the stern disapprobation with 

 which such arts were viewed, as aiming at gaining 

 the pleasures of wealth and the senses by demoniacal 

 aid. The State joined in this denunciation, and in 

 1404 the practice of alchemy was made a felony in 

 England. In 1689, however, this Act was repealed, 

 doubtless owing to the saner and more scientific atfT- 

 tude towards nature and the investigation of her 

 secrets then coming to the fore, and culminating in 

 the foundation of the Royal Society. Whilst, in fact, 

 alchemy and magical practices had little in common, 

 many seekers after the Philosopher's Stone were in- 

 spired by evil motives — by greed and avarice. But 

 others were true natural philosophers, and there was. 

 Archdeacon Craven suggested, a still higher alchemy, 

 which aimed, not at making material gold, but at the 

 transmutation of the soul's dross into spiritual gold. 



Attention may be directed to a paper in which 

 Mr. W. N. Haworth describes a " New Method of 

 Alkylating Sugars " (Trans. Chem. Soc, 1915, vol. 

 cvii., p. 8). This operation has been carried out pre- 

 viously by means of alkyl iodides and silver oxide, two 

 NO. 2364, VOL. 94] 



expensive agents which have the advantage of avoid- 

 ing complications, such as racemisation, the Waldcn 

 inversion, and the interconversion of glucosides. It 

 is now shown that similar results can be achieved in 

 aqueous solutions and at about one-fifth of the cost 

 by using alkyl sulphates and caustic soda as alkylat- 

 ing agents. In every case where comparison was pos- 

 sible, the optical rotatory power of the product was 

 equal to that obtained by the earlier methods, and it 

 is clear that the easier and cheaper preparation will 

 greatly facilitate synthetic experiments in the sugar 

 series. 



The January issue of the Chemical Society's 

 Journal contains a redetermination of the atomic 

 weight of tin by Mr. H. V. A. Briscoe, working in 

 Prof. Baker's laboratory at South Kensington. It is 

 remarkable that nearly all the previous determinations 

 gave values approximating to 118, with the exception 

 of five series of measurements by Bongartz and 

 Classen, which gave the value 1190, which has been 

 generally used ever since. Nearly all the early 

 measurements depended on the oxidation of tin to the 

 dioxide or the converse reduction, but it is doubtful 

 whether this oxide is a suitable substance for experi- 

 ments on atomic weight. On the other hand, all the 

 five methods of Bongartz and Classen depended on 

 weighing tin in the form of an electrolytic deposit on 

 platinum, and would be vitiated by the inclusion of 

 mother-liquor in the deposit. The new measurements 

 now described depend on finding the ratio, SnCI, : Ag. 

 Fifteen analyses gave numbers ranging from 118-678 

 to 118-714, and eleven of these fell between 118-690 

 and 1 18-71 1. The atomic weight finally deduced is 

 118-70, and seems to be worthy of considerable con- 

 fidence. 



The well-deserved popularity of the two-cycle hot- 

 bulb, or semi-Diesel engine, is directing the attention 

 of designers toward the perfecting of this simple type 

 of prime-mover. Earlier examples of this type were 

 rather uneconomical compared with the four-cycle 

 engine, but this objection has been gradually reduced. 

 In ease of starting, trustworthiness, etc., the hot-bulb 

 semi-Diesel engine has undoubted advantages over 

 some other forms. Engineering for Februarv 12 has 

 illustrated descriptions of an engine of this type made 

 by Martin's Cultivator Company, Ltd., of Stamford. 

 The engine illustrated gives 9 brake-horse-power at 

 475 revolutions per minute, and has a single cylinder 

 7 in. diameter by 8 in. stroke. Scavenging air is com- 

 pressed in the crank-case. The engine is started by a 

 blow-lamp, and will start in about three minutes from 

 cold on crude oil, and in five minutes on paraffin. 

 Regulating and governing are effected by varying the 

 stroke of the fuel-pump. There are many points in 

 the design of this engine which should make for 

 trustworthiness in v^orking and freedom from break- 

 down. 



The Engineer for Februarv 12 contains an illus- 

 trated description of the construction of the new 

 Mappin terraces at the Zoological Gardens in Regent's 

 Park. The area covered by the terraces and hills 

 takes the shape of a quadrant, and measures about 



