[ 32 ] 
author, Wallerius, in his Mineralogy , vol. ii. gen. 
p. 128. alfo recommends this method. 
In the Pbilojophical Tran faff ions, N°. 7. the fir ft 
method of Kircher is copied. The editor however 
therein fays, that method has not fince been tiied. 
He adds, that one Mr. Bird had for many years (he 
writes in 1666) found out a way to fink colours a 
considerable depth into polifhed marble ; pieces 
whereof were {hewn to King Charles II. Soon after 
his reftoration j and, being broken in his prefence, 
it was found, that the colours had penetrated deep 
into the marbles ; and that many works o' his coloured 
marbles were feen at Oxford and London. But Mr. 
Bird’s way of doing it is not mentioned. 
In the Philo/ophicai Pranjaffions, N°. 268 is a 
paper, intituled, “ The Way of Colouring Marble.” 
The anonymous author gives us an account of the 
colours, &c. he ufed. It is obfervable they are only 
vegetable colours. His red, he fays, he extracted 
again from the marble, without hurting the polish, 
within fix and twenty hours, with oil of tartar per 
deliquium ; and his brown was quite difcharged by 
aquafortis within one quarter of an hour, and the 
poliSh of the marble quite deftroyed. 
I Shall now proceed to give an account of the ex- 
periments I made. I could not well fuggeft any 
more, as the method of colouring the marble, the 
materials of the colours, &c. are kept fecret by the 
artift, Mr Chambers. 
A piece of marble, with the Several colours ufed, 
©n it, like a painter’s pallet, being greatly Saturated 
with aquafortis, at different times, for twenty hours, 
tho’ 
