150 
Quarterly Meeting, October 18th, 1859. 
Wm. Fairbairn, Esq., F.R.S., &c., President, in the Chair. 
The President announced the formation of a Mathemati- 
cal and Physical Section in connexion with the Society. 
Dr. F. Grace Calvert presented in the name of Mr. 
Arnaudon (from Turin), a Paper, and Samples of Green 
Colours used in Painting and Printing, and especially referred 
to two new chrome greens, one of which is a new compound, 
corresponding to the monohydrate of sesquioxyde of chrome 
Cr2 Q3 HO. 
The Author commences in his work to point out the 
qualities which a good green ought to possess, in order to 
be suitable for painting. Then he reviews in a few words 
the different greens which are found at present in the market, 
together with the nature and properties of the same. Begin- 
ning w’ith the history of the works already published on this 
subject, he next gives the description of his process for 
preparing his monohydrate of sesquioxyde of chrome, and 
which consists in exposing the bichromate of potash mixed 
with phosphoric acid and any desoxydizing agent (for ex- 
ample, ammonia) for some time to the action of heat. The 
soluble salts are then removed by washing. 
The green so prepared has not only a beautiful shade, hut 
like that of Mr. Guignet (made by decomposing the borate 
of oxyde of chrome by water) possesses the curious property 
of remaining green under the influence of artificial light. 
Dr. Calvert also presented some Muslins printed by M. 
Camille Ksechlin, of Mulhouse, with Fuchsine, a product 
obtained from the Aniline of Coal Tar. This colour was 
very remarkable from the exquisite bloom of the pink shade 
obtained when fixed with Albumen. 
Proceedings— Lit. & Phil. Society — No. 2.— Session, 18o9-60. 
