THE MANUFACTURE OF CALOMEL IX JArAX. 3 



mentions, as the result of his own observation, the characters of kiiig/un 

 and its great purity but for the presence of minute, transparent, 

 acicular crystals of calcium sulphate. He refers to Porter Smith's 

 Contributions towanU the Materia Medica and Natural Histonj of China 

 for an account of the manufacture. Smith, however, takes his in- 

 formation solely from Pearson's account on ]). 59, vol. iii of Sir J. 

 Davis's work on the Chinese. I have not seen this book, but it is clear 

 from P<3rter Smith that Pearson, again, has only derived his informa- 

 tion from the Chinese Materia Medica, Pun-tsaou-kang-muh. aud not 

 from his oww observation, and it amounts to tliis : — Common salt and 

 mercury, (jf each one oz.; alum, 2 ozs.; or, salt, mercury, copperas, and 

 saltpetre, in some such prijportions ; are rubbed together and put into 

 an iron bowl which is then covered with a roomy earthen dish well 

 luted down. This is exposed to the heat of a strong charcoîd fire for 

 four or five hours, when water is thrown on the cover and the cover 

 taken otf. On its inner surface the calomel is found adhering in the 

 form of a beautiful, feathery, white sublimate. Ten parts of mercury 

 are said to yield about eight parts of calomel. Dr. Geertz's paper, 

 alreadv referred to, contains essentially the same account translated 

 from the Japanese version of the Chinese work. 



Tastly, there is a paper, in the Japanese language, on the 

 manufacture of keij'un at Isc, which is the forerunner of the present 

 one. That pajjer appeared in 1887 in the Journal of the Tükijö 

 (lu'iiiical Socielii, l:)y Mr. T. Shiniidzu, ^l.E., F.C.S., my former 

 pu})il and colleague, ai-d it was his description to me of what he had 

 seen that led to my (jwn visit to Ise in company Avith Professor Haga 

 in the following year. In one or two points I have availed myself 

 of this paper to make my own account more com[)lete. 



(Jf the sjiecinc properties of keifun. — Keifun is in very thin 

 minute scales, lustrous, transparent, and white (jr faintly cream- 



