THE IMANUFACTÜliE OF CALOMEL IN JAPAN. 13 



and thnt the calimiel is not heated to its volatilisinfi- point, lie the 

 explanation and. at the same time, the assnran<"e. tliat .Japanese (and 

 Chinese) calomel contains no corrosive snhlimate. 



Suniniarij. — The Japanese pre])are ealomel pure, ahove all thinus 

 free ti-om corrosive sublimate. They heat l)alls of porons earth and 

 salt, soaked in bittern, alono- with mercnrv, in iron pots lined with 

 earth. The heat forms hydrt^chloric a<tid from the masrnesinm 

 chloride in the bittern, and tlie mercury sublimes into the closely- 

 fitting but unattached clay covers of the pots. Air enters by diffusion, 

 and oxygen and hvdrochloric acid ,o-as act together in the hollow cover 

 on the vapour given off from the sublimate of mei'cnrv there formed. 

 The cover thus becomes filled, with a network of micaceous particles of 

 calomel, precipitated, at a temperatui-e below its subliming point, at 

 the moment of its formation. "' " 



Tliis investigation of an intei"esting product of Japanese industy 

 has been carried out luider the authority of the Imperial University of 

 Japan. I cannot acknowledge fidly en(nigh the indispensable assist- 

 ance I have received from my colleague, Assistant- l*rofessor Haga. 

 F.C.S. 



