200 Royal Society at Gottingen. 
potafh. By potafh it was precipitated of a mountain blue co- 
lour; and, when fufed under this form with falts, communi- 
cated to themagreen colour. The flag alfo acquired the fame 
when the latter was, fufed with charcoal powder,, pounded 
glafs, borax, or its acid. As it diflolved, however, fo eafily in 
fluxing falts, he found it difficult to fufe it by this method 
to a metallic button, till it was firft precipitated by zine 
from the fluid flag; and it then gave a button. of a leaden 
grey colour, which, when melted with borax, communi- 
cated to it a green colour. Thefe characters fufficiently 
diftinguifh it from molybdena, which Bindheim fuppofed it 
to be, as well as from arfenic, which Lehman fought in it; 
though it agrees with both in this, that its calx readily 
affumes the properties of an acid, and with the laft, that when 
burnt on charcoal by the blowpipe it emits a like fmell. 
The other feries of experiments were made ‘with: the fo- 
called aurum problematicum, from which, after it had been 
well mixed with finely-pounded grains of quartz, the metal 
was extracted by frequent boiling in nitro-muriatic acid, and 
then'precipitated by potafh. The depofit being boiled’ with 
_cauftic ley, what the latter diffolved was again precipitated by 
an acid. What was then obtained melted very eafily by the 
blowpipe upon charcoal, without any remarkable fmell, but 
furrounded with a beautiful blue and green flame, into an 
almoft tin-white, hard, very brittle button, the whole furface 
of which had a granulated appearance; and when longer ex- 
_pofed to the heat it diffipated in flame and fmoke. It didnot 
diffolve entirely in pure nitric acid, but in the nitro-muriati¢, 
What was precipitated from both exhibited the fame’ phe- 
nomena by the blowpipe as'the former metallic button. It 
i8 not precipitated by zinc and iron only, but alfo by copper. 
From thefe properties it appears to differ from all the metals 
hitherto known. Profeffor Klaproth has given it the name 
of Tellurium. 
FRENCH 
