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TRANSACTIONS OF THE SECTIONS. 55 
specific gravity of the mixed gases, the flies were unable to mount on the wing, or 
make the usual buzzing noise; but the substitution of hydrogen for nitrogen in the 
atmosphere had no marked effect upon their breathing ; thus confirming the observa- 
tions of M. Regnault by an instance drawn from the Articulata. 
On the Sulphite of Lead. 
By WitiiaM Grecory, M.D., Professor of Chemistry. 
In Dr. Scoffern’s process for purifying and extracting sugar, the albuminous matters 
are precipitated by acetate of lead, and the lead remaining in solution is thrown down 
by sulphurous acid gas as insoluble sulphite. 
In the event of lead being found in the sugar thus prepared, and it appears that a 
minute trace may thus be found, owing to imperfect filtration, it must be in the form 
of sulphite ; and I thought it most desirable to examine the properties of this salt. 
The sulphite of lead is one of the most insoluble salts known, far more insoluble than 
the sulphate; indeed it may be called absolutely insoluble, As the sulphate has 
always been considered inert, and indeed sulphuric acid is used as an antidote to 
poisoning by lead on this account, it appeared most probable that the sulphite would 
likewise prove inert. To test this up to a certain point, I prepared a quantity of pure 
sulphite of lead, and gave it, in the moist state, to rabbits and dogs with their food. 
The animals all took it readily and throve upon it, although large doses were daily 
given for periods varying from three to six weeks. The rabbits, being well-fed, be- 
came very fat, and continued quite healthy. 
It is well known that very minute doses of carbonate of lead, when long continued, 
produce poisonous effects. I had not the opportunity of testing the effect of very 
minute doses of the sulphite for very long periods; but I think it reasonable to con- 
elude, that as the large doses, continued for six weeks, had no deleterious action 
whatever, the sulphite of lead is essentially inert and innocuous, Besides its insolu- 
bility, it is remarkable for stability; and so strong is the action of sulphurous acid on 
the salts of lead, that it changes the black sulphuret into a white powder. In pre- 
sence therefore of an excess of sulphurous acid, no lead can be left in solution. 
In conclusion, sugar prepared by Dr. Scoffern’s process, and probably containing 
as much lead as was found in the samples analysed by the Commission, has been used 
for months by families without any bad results. As long then as no such results, 
haye been observed, and my experiments tend to show that they are not to be ex- 
pected, it would be wrong to reject the very great improvement of Dr. S. merely be- 
cause a-trace of lead (and that, not as carbonate, the truly poisonous compound) has 
been found in the sugar prepared by his process. It may also confidently be expected, 
that, by improved means of filtration, even the minute trace of sulphite of lead, hi- 
therto found, will be entirely got rid of. 
.----ς-.-. 
On some Amalgams. By J. P. Journ, F.R.S. 
The author had procured an amalgam of iron by precipitating it on mercury by 
the electrotype process. He had subsequently pursued the research with a view to 
form definite amalgams by a simple chemical or mechanical process. When mercury 
was made negative under a solution of sulphate of copper, an amalgam of copper was 
formed, which, when fully saturated with copper, was found to be represented by the 
formula Cu+Hg. | 
The author also exhibited a small apparatus whereby amalgams could be made to 
endure a pressure of 60 tons per square inch of surface. The superfluous mercury 
was thus expelled through the openings in the sides of the press, leaving an amalgam 
of definite chemical composition. In this way he had procured the following com- 
pounds :— 
Pt+2Hg 
Ag+2H¢g 
Cu+ Hg 
Fe+ ' Hg 
2Zn+ Hg 
2Pb+ Hg 
7Sn+ Hg. 
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