DEPARTMENT OF THE ARTS. 



VERMILLION BY A NEW PROCESS— ITS PHOTO- 

 GRAPHIC PROPERTIES. 



Milwaukee, February 13, 1873. 



Dr. J. W. HoYT, President Wisconsin Academy of Sciences^ Arts and Letters: 



My Dear Sir : Enclosed I send you a sample of Vermillion 

 obtained by wbat I suppose to be a new process, without sub- 

 limation or heat, and without the use of an alkali, but directly 

 from solution by deposition. I find no account of its being 

 produced by such method in any work which I have been able 

 to consult. As produced by my process it has photographic 

 properties^ which fact, I believe, has never been noticed. If 

 deposited in a weak light, or in the dark, it turns much darker 

 on exposure to strong light while yet remaining in the solution 

 from which it was deposited. This property gives the sub- 

 stance great value in its application to photography, for prints 

 after being toned by the mercuric sulphide become more deeply 

 impressed after completion ; whereas by the usual method the 

 last thing done in the production of the print is to subject it 

 to the action of h3^po-sulphite of soda, which gTcatly weakens 

 the force with which it adheres to tlie organic surface. This 

 sulphide is a stable substance, does not dissolve in nitric, muri- 

 atic or sulphuric acid except by aid of heat, and is not affected 

 by ordinary conditions of the atmosphere ; and by enveloping 

 the silver and gold depositions composing the photographic 

 print, with it the print is thus enabled to resist the destructive 

 L. 



