166 Wisconsin Academy of Sciences, Arts, and Letters. 



agencies wMch otherwise would cause it to fade. The reac- 

 tions whicli take place in the formation of the sulphide in 

 question are probably represented by the following equation : 



Na^ S^ O' + Hg CP + NH^ CI = 

 Hg S^ + 2(Na CI) + NH* Clo\ 



The Vermillion itself does not rival the commercial product 

 in beauty of color, but I think will do very well for the first 

 result of a new process. I expect to learn to produce a finer 

 article. 



Until very recently, I had expected to be present at your 

 next meeting and present this matter in person to the Acad- 

 emy, together with illustrative specimens, but circumstances 

 will prevent. 



Very truly yours, 



W. H. SHERMAN. 



