pe and its Utility in the Arts, 27 
for me efcapements and compenfation balances. THe is of 
opinion, that this metal is extremely proper for the holes in 
which the pivots move, becaufe it preferves oil without the 
leaft alteration. Platina has no occafion, like gold, to be com- 
bined with any other metal, to render it fit for being ufed in 
the arts. This new metal afforded me excentrie watch dial- 
plates fuperier to thofe brought from England. Cotteau, 
an ingenious enameller, who himfelf made various expe- 
riments with platina, told me, that for his art he preferred 
it to all other metals. Platina is alfo a metal of ineftimable 
value for conftructing different inftruments of chemifiry. I 
have formed it into crucibles*. 
The experiments which I lately made at Saint Gobin with 
Deflandes, director of the plate-glafs manufactory, do not 
permit me to doubt of the utility of crucibles made of pla- 
tina in bringing flint-glafs to perfection ; and Deflandes, who 
has been able to give to the glafs of Saint Gobin a fupe- 
riority which foreigners cannot difpute, is of my opinion in 
regard to crucibles of this metal. Crucibles indeed of earth, 
whatever be its nature, become in part vitrified. The glafs 
which thence refults is imperfeét ; and it may be feen by the 
naked eye, that the-vitreous fub{ftance contained in the cru- 
gible does not form one homogeneous mafs. . It may be 
readily perceived, that crucibles of platina cannot be attended 
with the fame mconvenience. 
[To be concluded in the next Number. ] 
* Since this memoir was read, I caufed to be caft a crucible of platina 
capable of containing thirty pounds of flint-glafs; and to give it more 
t g YP Bas $ 
. firength, it is covered on the outfide with a cafe of caft iron an inch in 
thicknefs. In the latter operation I was affifted by my colleague Perrier, 
IV. Cit, 
