292 M. Braconnot on Sorbic Acid. [Oct. 



M. Braconnot also formed an acidulous sorbate of lime, by 

 dissolving the neutral sorbate in sorbic acid. This salt presents 

 prismatic crystals, with six faces ; it is very acid, and requires 

 for its solution no more than 50 parts of water at the temperature 

 of 53-5°. It is composed of 



Sorbic acid . . . 65-48 84-63 100-000 



Lime 11-99 15-47 19-483 



Water 22-53 



100-00 100-00 



M. Braconnot has procured three sorbates of zinc, a neutral 

 sorbate, a super-sorbate, and a sub-sorbate. The neutral sor- 

 bate is formed directly by combining the sorbic acid with the 

 oxide of zinc, or in decomposing the sorbate of lime by sulphate 

 of zinc. It is composed of 



Sorbic acid.. .. 58-05 64-5 100-000 



Oxide of zinc. .. 31-95 35-5 55-426 



Water 10-00 



100-00 100-0 



The super-sorbate is prepared by dissolving neutral sorbate of 

 zinc in sorbic acid, and washing the crystals in alcohol or in 

 water. It contains 



Sorbic acid 71-88 78-41 



Oxide of zinc 19-79 21-59 



Water 8-33 



100-00 100-00 



The sub-sorbate of zinc separates naturally from the watery 

 solution of the neutral sorbate • it is insoluble in boiling water, 

 and consists of 



Acid 51-89 



Oxide of zinc 48*11 



100-00 



M. Braconnot has examined the sorbate of lead ; he finds that 

 there is no super-sorbate, and that its solution in water does not 

 redden litmus. By examining the crystallized sorbate of lead, 

 well dried, and afterwards calcined in a platinum crucible, he 

 estimated that it was composed of 



Sorbic acid 38-85 100-0 



Oxide of lead 61-15 157-4 



100-00 



