30 Improvements in Physical Science [Jan, 
Composition of alloy. |Lead necessary to] Ratio between 
[cupeHlate 1 of the |the lead and the 
Silver, Copper, alloy. copper. 
1000 O po 0) to ] 
950 50 3 60° Sto 
900 100 7 70> 4Qe 
800 200 10 50 to 1 
700 300 12 40 toi 
600 400 14 35 tol 
500 500 1G to 17 32 tol 
400 600 16 to 17 26°66 tol 
300 700 16 to 17 22°857 to | 
200 800 16 to 17 20 to l 
100 900 16 to 17 i777 tot 
1 999 16. t0' 17, 16°016 to 1 
O 1000 16 to 17 16 to 1 
The proportions used at our mint are, I have been told, much 
more economical than these. 
4. Mercury.—A curious paper on the combination of mercury 
with oxygen and sulphur has been recently published by M.Guibourt. 
It is well known to chemists that two oxides of mercury exist; but 
M. Guibourt has shown that the protoxide cannot be obtained in a 
separate state. When the proto-chloride of mereury (calomel) is 
treated with an alkali, a black powder is obtained, which has been 
considered as protoxide of mercury. But when examined by a 
magnifying glass, globules of mercury may be detected in it. They 
become visible to the naked eye when the precipitate is pressed be- 
tween two bodies, According to M, Guibourt, the protoxide of 
mercury is composed of 
MIEROMEY | fgi4 «665° late mel AGl et - 359 saramse ex, LOO 
OBO Gs adel oats oh » Disilole bis eleibieJeraye Gigiehi Uae 
and the peroxide of 
Mercury, 2... < store gra rmparinte: ota. ai'e Neste) art raise Cn 
RUIN Unita a's ‘efaite. =o eig G 1ehe acre eye enrtatainy= 8 
When sulphureted hydrogen gas is made to act upon proto-chlo- 
ride of mercury, a black powder is obtained, which has been 
hitherto considered as a compound of mercury and sulphur. But 
M. Guibourt finds that globules of mercury become visible in it 
when it is compressed. On that account he does not consider it 
as a sulphuret. But as he finds it to be composed of 100 
mercury + 8 sulphur, which corresponds exactly to an atom of each 
of these bodies, 1 do not see how we can refuse to consider it as a 
chemical compound. Cinnabar is formed when an excess of 
sulphureted hydrogen is mixed with deuto-chloride of mercury, It 
l 
