254 REPORTS ON THE STATE OF SCIENCE. 



more to our knowledge of the constitution of the caoutchouc molecule 

 than any other previous investigation. 



Harries/ as a result of his studies on autoxidation, was led to 

 examine the effect of ozone upon unsaturated compounds. He found that 

 on passing ozone through compounds or solutions of compounds of the 

 type of mesityl oxide, highly explosive bodies were formed, which he 

 considered to be of the nature of peroxides, the oxygen adding on at the 

 double bond. 



> C = C < — > > C = C < 



I I 

 0-0. 



The effect of water on these compounds was to produce a splitting up 

 at the point where the double linkage had been, giving aldehydes and 

 ketones. Afterwards,^ from analysis of some of the explosive com- 

 pounds, he proved that the bodies were not peroxides, but that three 

 atoms of oxygen (one molecule ozone) were added on at the double bond, 

 and he gave the name ' ozonides ' to this class of substances. 



The action of ozone on unsaturated compounds can be formulated as 

 follows : — 



(1) >C = C<+03=>C C< or >C-C< 



II II 



0^0-0 0-0 



%^ 



o 



and the action of water in decomposing these bodies is represented : — 



(2) C- C + H,0= >C0 0C< +H,0., 



I I ■ 



o o 



\/ 



o 



hydrogen peroxide being detected in large quantities in the resulting 

 liquids. 



In 1904^ pure Para rubber dissolved in chloroform was submitted 

 to the action of ozone. On distilling off the chloroform a colourless 

 .syrup remained, which on drying in a vacuum solidified to a glass 

 and possessed all the properties of the ozonides. After purification it 

 was dried in a vacuum, and analysis showed it to have the empirical 

 formula C,nH|r,Og, indicating the addition of two molecules of ozone 

 to the C|oH,g group. On decomposition of the ozonide with water 

 hydrogen peroxide was formed, and the liquid obtained gave the charac- 

 teristic reactions of a ketone or aldehyde. 



By heating the ozonide for a long time with water, however, com- 

 plete solution of the products took place and the hydrogen peroxide reac- 

 tion disappeared. From the residual liquid levulinic acid was obtained and 

 an acid melting at 19.5°, probably a succinic acid. The acid thus pro- 

 duced was obviously the oxidation product of levulinic aldehyde, and 

 enabled Harries to locate the double linkages in the CioHm molecule. 



' £er., 36 (1903), 1923. ^ Ber., 37 (1904), 839. > Ber., 37, 2708, 



