34, PBftliiANENT WHttE FOB WATER COLOtTlLSi 



ApermaHcnt celfcbrattd chemist, that It is the duty of every one t o d6 

 white for water ^.j^j^^ he can towards the arfvaucernent bf t»eneral Science, 



colours. ° 



I am induced to lay before the public, through the highly 

 respectable merlium of the Philosophical Journal, a nt*^ 

 and easy method of preparing a beautiful permanent white 

 for v^ater colours, calculated to stand the test of time ; 

 which, 1 understand, is at present a great desiduraturft 

 among our artists. This being the case, I entertain a con- 

 fident hope^ that the present discovery may prove enlinently 

 useful. 

 Mentioned by Through the information df a chemist of the name of 

 Mr. Hume. tiu^e, the public is already in possessibn of the facts, that 

 a colour can be prepared from baiytes; aod that this earth 

 tvill furnish the only white for water painting, that never 

 changes; which may also be mixed with any other colour 

 without injury ; but of its mode of preparation we have 

 hitherto, 1 believe, remained entirely ignorant. This beau- 

 tiful pigment, which not only surpasses in opacity and 

 whiteness every thing of the kind L have ever met with, but 

 possesses the peculiar advantage of being permanent, is 

 prepared by the following simple process: Dissolve pure 

 barytes, or the common native carbonate, in diluted nitro- 

 muriatic acid; filter the solution, and add thereto as much 

 carbonate of ammonia, previously dissolved in distilled 

 water, as is sufficient »to precipitate the earth; which may 

 be separated by filtratiouj and, after repeated washings with 

 distilled water, must be gradually dried by the heat of the 

 sun, or a fire, and rubbed into a very fine powder, or made 

 up into cakes for use. I decomposed some nitro-mxiriate of 

 barytes with a solution of pure ammonia, but the precipitate 

 TVas very inferior in colour to the above. An artist of ac- 

 knowledged celebrity, who has used this white, speaks very 

 encbur&gingly of it. 



i remain, respectfully^ 

 Brighton, 8fh mo, Ath, GROVER KEM^**% 



1811. 



Yirh 



