[ i8 3 
S I L V-E R. 
YELLOW is' the only colour which fihe?', 
the metal next to lead in denfity, can by any prepa-* 
ration be made to impart to glafs. 
1. Without infilling upon what fome chymifts 
affirm, that Jilver, on being calcined and ex- 
pofed to a violent fire for a long time, was partly 
reduced to z. yellow glafs [«], 
2. I have often given that colour^ by moiftening the 
furface of the glafs with a folution of Silvery and 
^ afterwards making it red hot. 
3. If Silver be calcined with fulphur, it readily 
- communicates 2. yellow colour to glafs [^?]. 
a very Hyacinthy and not much differing from the true one, put 
lead into earthen pots that are very hard, in a glafs furnace, and 
there let it ftand fome days, and thus your lead is turned into 
gleifsy and 'imitates the colour of the Hyacinth. 
. Nichols’s Hiftory of precious ftones, part i. chap. 7. of the 
Hyacinth. 
The Hyacinth is a ftone (as faith Boetius and Rulandus) 
which is red with a certain yellownefsy or rufefcit in auro ; that is, 
it is red\n yellow. Impoftors adulterate it w'ith a kind glafs 
Tnade of Lead. 
Boetii gemmarum et lapidum hiftoria, 1 . ii. c. 31. Adultc- 
lium Hyacinthi vix mcretur ; in illius locum aliquando fubftitui- 
tur ex plumbo vitruiUy quod a vera gemma pondere et duritic 
facile diftinguitur ; mollius enim et gravius vera gemma. 
[«] Merret’s Notes on Neri, chap. 82. Claveus faw Silver 
calcined two months in a glafs furnace ; the twelfth part of 
which became a citron glafs. 
[c] Shaw’s Abiidg. of Boyle, vol. i. p. 458. To flicw more 
particularly that glafs is porous, wc took fiver calcined by 
burning on it in the open air, and laid it upon a piece of 
gtafy and placed it with the pigment uppermoft, upon a few 
4. Having 
