C 31 1 
The artid, whom I alfo introduced at the fame 
time to the Society, is Mr. Robert Chambers, of 
Minching-Hampton in Gloucederfhire ; and at my 
delire he was prefent at the experiments I made on 
his faid painted marbles. 
But before I relate the experiments, it may not 
be improper to give fome little hidorical account of 
the art itfelf : it will at lead; be amufing to the 
Society. 
Kircher, in his Mundus Subterraneu r, lib. viii. fed. 
I. c. 9. p. 45 & 46. is the firft author I know, who 
mentions it. There was, fays he, an artid at Rome, 
w r ho painted feveral pieces of marble, in an elegant 
manner, for Pope Urban VIII. He would not dif- 
cover his art ; therefore Kircher drove by many ex- 
periments to difcover it : and he made colours, viz. 
tindures of metals and minerals, which coloured 
the marble as finely as any the artid had done, and 
quite penetrated the done ; infomuch that a flab cut 
horizontally made as many pictures as pieces or fee- 
tions. Kircher gives' at large the procc-fs he ufed for 
making the colours ; and obferves, they fhould ahvay9 
be of a mineral origin : which I incline alfo to believe 
would anfwer much the bed. 
The faid author (Ibid.) alfo gives another method 
to colour marble, by vitriol, bitumen, &c. forming a 
defign of what you like upon paper, and laying the 
faid defign between two pieces of polidaed marble ; 
then doling all the interdices with wax, you bury 
them for a month or two in a damp place. On 
taking them up, you will find, that the defign you 
painted on the paper has penetrated the marbles, and 
formed exadly the fame defign on them. A modern 
author, 
