79 



oil. Products were obtained identical with those prepared from 

 hop oil by GRESHOFF 1 and WAGNER* and PERSONNEL 



Further researches of the author's were made concerning the 

 a-acid. This acid, although it yields a well-characterised lead salt, 

 can be obtained quite pure only with great difficulty ; consequently 

 the results may be somewhat unreliable. The analytical data were 

 confirmed by M. BAMBERGER and LANDSIEDL*, but these authors 

 propose for the a-acid the formula C 20 H 28 O 5 or C 20 H 30 O 5 , basing 

 it on a determination of the molecular weight made with purer 

 material. The action of melting potash on the a-resin indicated a 

 relationship between that resin and hop oil, as also the /3-acid. Like 

 the latter, the a-acid is an unsaturated compound. When treated 

 with potash-lye and sulphuric acid, the a-acid furnishes a body of acid 

 character the nature of this substance could not be determined owing 

 to lack of sufficient material. Although the a-acid closely resembles 

 the /3-acid in many of its chemical properties, and apparently belongs 

 to the same class of substances, it is distinguished by physical 

 differences (melting point, solubility, crystalline form) ; by its 

 elementary composition ; and by the fact that it gives a crystalline 

 decomposition product when acted upon by potash solution and 

 sulphuric acid. 



T. ScHNELL 5 has recently studied the a-acid, and his results 

 furnish additional information as to its constitution. Two decom- 

 position products are formed by the action of soda solution an 

 unsaturated oxyketonic acid (C 15 H 24 OJ and valeric acid, which 

 latter is also produced on the oxidation of the substance. The 

 oxyketonic acid is not identical with the product obtained by the 

 author in the same way, nor with that produced by ISSLEIB by the 

 action of sulphuric acid. 



From the decomposition products of the a-acid SCHNELL ascribes 

 to it the formula C 2 H 3 2 O 5 , which differs only by two hydrogen 



1 Inaugural Dissertation, Jena, 1887. 



2 Erdmann' s Journal fur Praktisclie Chemie, 58, 351. 

 8 Comptes Rendus, 1854, 309. 



4 Zeitschrift f. d. ges. Brauwesen, 1902, 461. 



5 Inaug. Diss. Tech. Hochs. Munich 1904. Zeits. f. d. ges. Brauw, 1904, 666. 



