June 17, 1909I 



NA TURE 



47r 



of cryolite, which occurs in quantity only in south-west 

 Greenland. After a rough hand-picking, the mineral is 

 shipped to Copenhagen, where it is purified. It is at 

 present employed as a constituent of a leadless glaze and 

 for the electrolytic production of aluminium. Dr. C. H. 

 Desch read a paper on eutectic alloys, and discussed the 

 suggested method for predicting the position of the 

 eutectic point. I-"lavitzUy"s rule was shown to rest upon 

 an insufficient theoretical basis. 



In the section for organic chemistry the great majority 

 of the papers read were of importance in their technical 

 bearing, but a certain number dealt with subjects of 

 theoretical interest. On Friday, May 28, all the papers 

 read related to hydrocarbons and their simple derivatives. 

 Dr. M. Z. Jovitrhitch communicated the results of his 

 e.\periments on ihe action of the silent electric discharge 

 on ethylene and acetylene. The remarkable statement was 



the chemistry of cellulose. Prof. Wichelhaus described the- 

 formation of pure phenol during the destructive distilla- 

 tion of cellulose, no other phenols being detected. In 

 reference to the mercerisation of cotton. Dr. Vieweg dealt 

 with the action of cuprammonium solutions on cotton 

 cloth. The mercerising effect was found to decrease with 

 rise of temperature. Dr. Hiibner stated that caustic soda 

 lye of specific gravity 45° Twaddell caused the maximuni 

 degree of mercerisation. Prof. Knecht gave an account 

 of the action of certain dicarboxylic acids on cellulose. 

 When cellulose is treated with oxalic acid, formyl cellulose 

 is produced by loss of carbonic acid. Similarly, malonic 

 acid and its derivatives yield acetyl cellulose and the corre- 

 sponding acyl derivatives of cellulose. With succinic ancf 

 glutaric acids this effect is not produced. 



On Monday morning. May 31, the subjects under dis- 

 cussion in the section of organic chemistrv were colloids,. 



Section I., Analytical Chemistry, of the International Congress of Applied Chemistry. 



made that in all cases the analyses of the total resultant 

 products showed a deficiency in carbon, always above 

 10 per cent, and often so great as 20 per cent. More- 

 over, when these products were allowed to stand in open 

 vessels the carbon content was observed to rise, sometimes 

 to the extent of 5 per cent. These substances were found 

 to fog photographic plates through the dark-slide, and 

 were therefore considered to be radio-active. 



Dr. Gustav Roller gave an account of the chloro- 

 hydrocarbons produced by the action of chlorine on 

 acetylene under the influence of ultra-violet light. The 

 utility of these substances as non-inflammable and non- 

 explosive solvents for fat extraction and other purposes 

 was emphasised. 



On Saturday, May 29, the communications in the section 

 for organic chemistry dealt with the chemistry of naturally 

 occurring hydrocarbons, such as the terpenes, with cellu- 

 lose, and with the synthesis of alcohols. With regard to 



KG. 2068, VOL. 80] 



fatty acids, &c., paints and varnishes. Mr. H. R. Procter 

 discussed the structure of organic jellies, advocating the 

 view that jellies consist of a solid solution of the solvent 

 in a network of colloid molecules. Doubt is cast upon 

 the justice of a distinction between colloidal and " true " 

 solutions, the difference depending merely upon the size of 

 the molecules or molecular aggregates. Prof. Haller, of 

 the Sorbonne, read a paper on the alcoholysis of certain 

 esters. The esters, on being heated with a i per cent, 

 solution of hydrochloric acid in methyl alcohol, were 

 quantitatively converted into the corresponding methy 

 esters. This method was found to be especially applicable 

 to the case of fats, glycerine and the methyl es.ter of the 

 fattv acid being produced. In another paper the same 

 author gave an account of the action of ozone upon the 

 methyl ester of ricinoleic acid. Results somewhat different 

 from those obtained by Harries and Thieme were observed. 

 M. Jean B. Senderens described a new method of pre- 



