Januaby 23, 1903.] 



SCIENCE. 



147 



of the proceedings of the meeting, to include 

 also the constitution and by-laws. The offi- 

 cers for the ensuing year were selected as 

 follows: President, C. M. Edwards, Trinity 

 College, Durham; Vice-President, C. E. 

 Brewer» Wake Forest College; Secretary - 

 Treasurer, Franklin Sherman, Kaleigh; Ex- 

 ecutive Committee, Messrs. C. M. Edwards, 

 Franklin Sherman, F. L. Stevens, W. G. 

 Sackett, H. H. Brimley, C. E. Williams, W. 

 L. Poteat, Chas. Baskerville, Collier Cobb. 



F. S. 



AMERICAN CHEMICAL SOCIETY. NORTHEASTERN 

 SECTION. 



The fortieth regular meeting of the section 

 was held at the 'Tech Union,' Garrison St., 

 Boston, Friday, December 19, at 8:00 p.m.. 

 President A. H. Gill in the chair. About 

 150 members were present. Dr. Carl Otto 

 Weber, of Manchester, England, gave a very 

 interesting talk on ' India Rubber, its Chem- 

 ical and Technical Problems,' in which he 

 first described the preparation of the gum 

 from the milk as it exudes from the trees 

 when they are tapped, and showed that the 

 coagulation of the milk is influenced by the 

 albuminous matters which are always present. 

 If these substances are allowed to coagulate 

 with the rubber, it is impossible to remove 

 them afterwards, and they become the source 

 of the injurious fermentation which often 

 occurs in crude rubber. Pure rubber free 

 from albuminous matter, even if shipped wet, 

 will not ferment at the extreme heat to which 

 it is often subjected in the holds of vessels, 

 and arrives at its destination in perfect con- 

 dition. It is thus of the greatest importance 

 to use a process of curing in which the al- 

 bumen is removed before coagulation. 



Dr. Weber then took up the question of 

 the chemical composition of rubber, showing 

 that rubber, freed from albuminous and resin- 

 ous substances, no matter from what source 

 the rubber is derived, consists of two sub- 

 stances; one, amounting to four per cent, 

 or less of the total, insoluble in all solvents, 

 contains oxygen, and has the empirical for- 

 mula, CjoHjgO^; the remainder is a hydrocar- 

 bon (CioHj,)„. As to the constitution of this 



hydrocarbon, it is undoubtedly a polymer with 

 a very high molecular weight. On dry dis- 

 tillation it gives C;H„ isoprene, CjoHj,, in- 

 active limonene, and CjjH,„ the so-called 

 heveene. The last two compounds are cyclo- 

 terpenes, but isoprene is an open chain com- 

 pound, with two double bonds, and has the 

 formula, 



H,C = C — C = CH2, 



H CH3 



or 2-methyl-l, 3-butadiene. Isoprene, on 

 Standing, polymerizes into rubber, or poly- 

 prene as it has been called on this account. 

 There is evidence to show that isoprene is 

 the main primary product of the dry distilla- 

 tion of rubber, and that limonene and heve- 

 ene are secondary products derived from the 

 isoprene. Rubber forms addition products 

 with chlorine, bromine, etc.; also extremely 

 interesting compounds have lately been dis- 

 covered, which are formed by the action of 

 oxides of nitrogen on rubber. These com- 

 pounds, (C,,H„K03), and (CJT,„E",0.)„ are 

 produced quantitatively from all varieties of 

 rubber, and are soluble in many solvents. 

 They, therefore, furnish valuable aid in the 

 analysis of rubber, and open up a very prom- 

 ising road for the further investigation of 

 its constitution. The fact that rubber is a 

 highly polymerized unsaturated hydrocarbon 

 with an open chain, and probably three 

 double bonds for C,„H,„, shows why all at- 

 tempts to make rubber by polymerizing those 

 terpenes, C,„IIjj, which are known to be cyclo- 

 compounds with only two double bonds have 

 not led to success. Attention was also called 

 to the recent work of Kondakoff, who has 

 obtained a compound, 



H,C = C — C = CHj, 

 CH3 CH3 

 or 2, 3-dimethyl-l, 3-butadiene, which is seen 

 to be a methylisoprene. This substance, on 

 standing, was converted quantitatively into a 

 white spongy mass, tasteless, odorless and in- 

 soluble in all solvents, which is probably a 

 methyl derivative of rubber, or methylpoly- 

 prene. Thus a very important step has been 

 taken in the synthesis of rubber. 



