The Manufacture of Calomel in Japan. 



By 



Edward Divers, M. D., F. R. S., Prof. 



Imperial University. 



(With Plates T-JÎT) 



Introductory. — Calomel, in the fonu common in England and all 

 countries under Western civilisation, is now extensively used and is 

 even manufactured in Japan, under the name of Imnhö. But mer- 

 curous chloride is also iarü-ely used here, under tlie name of ' light 

 powder,' Irifun (Chinese, h'ni(jfuii), in another and very much older 

 form, which is of signal qmrity, and made hy a simple process as yet 

 quite unknown in Europe. I witnessed this interesting process from 

 beginning to end some years ago, and now make this publication of 

 it with full permission of the proprietor of the works I visited, Mr. H. 

 Kokubu, who has aided me in every way he could, and notably with 

 drawings, some of which illustrate this paper. 



Historieal. — According to Terajima Hökyö and Ono Ranzan, 

 writers who lived in the last century, the Hrst-named perhaps a little 

 earlier, calomel was known in Japan as far back, at least, as the 

 beginning of the eighth centiu-y, having then been presented to the 

 Empress Gen-miyô ; but their authority is the Zohi Niliongi, reference 

 to which, Professor Haga, F.C.S., informs me, makes it clear that 

 mercnry itself, not its chloride, was the thing presented. In the time 

 of the writers above named, mercurous chloride was well-known and 



