Atomic Weight of Mercury. 321 



relating to it be thoroughly investigated, and established with all 

 possible certainty. Surely, it cannot be a very diflicult matter 

 to determine whether protoxide of mercury (for example) con- 

 sists of 200 parts (by weight) of mercury, and 8 of oxygen, or 100 

 mercury, and 8 oxygen ; — or whether protochloride of mercury 

 is composed of 200 M. + 36 Chlo., or 100 M. + 36 Chi. ;— and it 

 appears to me that it requires nothing more than the determina- 

 tion of these or similar questions, to decide whether the chemical 

 equivalent of mercury is 200 or 100. I think it much to be de- 

 plored that a matter of this sort should be suffered to remain in 

 a state of uncertainty, and I do, therefore, earnestly hope that 

 some of your correspondents will take up the subject and give 

 the result in an early number of your valuable Journal. With 

 great respect, I am yours, &c. A. B. H. 



P. S. — If you think the following worthy of a place, I would 

 thank you to insert it. 



In the fourth edition of Ure's Chemical Dictionary, published 

 in London the present year, is an article which shows a most 

 lamentable ignorance of the progress of chemical science and 

 discovery in this country. The article is one concerning sangui- 

 narine ; or, as Dr. Ure, in defiance of all analogy, spells it, sangiii- 

 nari. He sets out with a doubt whether it is in fact a vegetable al- 

 kali, and then goes on to say, it was first " obtained by M. Dana," 

 whom (from the title he gives him) he probably considers a French- 

 man. The whole matter is dispatched in six lines, while Delphi- 

 nine, an article not a whit more important, occupies seventy. The 

 fact that sanguinarine is a vegetable alkali, was fully established 

 five or six years ago. The properties of the substance, and those of 

 many of its salts, have since been investigated to a considerable ex- 

 tent. Details of the processes for obtaining the alkali and its salts, 

 have often been published in the medical journals of the country, 

 and in some treatises on chemistry ; and if I mistake not, in some 

 places the article is used in medicine with considerable success. 



I would recommend to Dr. Ure, that before he publishes a fifth 



edition of his Dictionary, he should take a look at the New York 



Medical and Physical Journal, Vol. 6, p. 218. American Medical 



Recorder, Vol. 13, (Phil. 1827,) and Silliman's Chemistry, Vol. 2. 



Neio York, Dec. 5, 1831. A. B. H. 



We have published with pleasure the communication of 

 Vol. I.— 41 



