‘358 Experiments on Prussic Acid. [Misy, 
wires, ‘and the portion of ‘the tube through which the spark passed, 
was covered by'a slight’ bistre-coloured coating, showing that carbon 
hhad sbeen:precipitated, or’at least a very-carbonaceous combination. 
On. analyzing the gas, J obtained 'in fact’a little-‘less carbon than ‘the 
calculation indicated. -As'to'the azote and hydrogen, 1 ‘found theth 
mearly in the same proportion ‘as ‘in the‘preceding analyses. low- 
ever, ‘this experiment, ‘not having ‘given ‘me satisfactory results, 
after having twice repeated it, and being very tedious, I did ‘not 
think it worth while to persist ‘in it any longer. 
The analysis of prussic ‘acid whieh I‘have-given ought 'to precede 
tthe examination ‘of its action on other bodies. This examination 
will not any longer present any difficulty; but before undertaking it, 
I must ‘remark that my results are ‘quite different from those obtained 
by Mr. Porrett; for, aecording to him, prussic acid is composed ‘of 
CAEDOM. “ok ite cccnsie ncdancaniy Sieeireae Gh beeen 
PP tics dees wines i pingeien sab «>i hte Caan 
FA YGra gen o.0.0:0, o:0s-0re viecwwem sierere shew OAD 
100°0 
But, according to ‘my analysis, of 
Carbon .5..0scnusevevncwiecrexesee 44°39 
BZDES fe sued omidinns wimp dowertiocnssb siesta ee 
Hydrogen «v0.4 snap oem dpyeieied 9s oe em (IO 
——— 
1 60°00 
Not knowing his memoir but by the very concise extract of it 
given by Dr. Thomson, it is not in my power to explain the cause 
of this great difference; but it is evident that the proportion of 
hydrogen which he gives is too great.* pa? 
In examining the properties of prussic acid, I shall not restrict 
myself toa rigorous arrangement, _I shall state my experiments in 
the order in which they will throw light on each others Prussic acid 
containing three elements, ought necessarily to possess great mobi- 
* Mr, Porrett’s analysis was made by heating a mixture of prussiate of mercury 
and red oxide of mercury. He obtained one volume of carbonic acid gas and 
half a volume of azotic gas; and he inferred the quantity of hydrogen from tle 
oxygen which had disappeared over and above what was necessary for the forma- 
tion of the carbonic acid. His result was as follows :— ‘ 
ND Mea Werae ss att oe ate Seite a/Selate 6 34°83 
PAGE 0 SPOR AM 3 40°T 
Eby dPOSEN gs) vnicits cbidd otaad Stelle Add 245 
100-0 
The proportions of carbon and azote are the same as those given by Gay-Liissac, 
The hydrogen is too great, because Mr. Porrett supposed the mercury i prussiate 
of mercury was in the state of oxide, This greatly increased the supposed aan 
of oxygen consumed. Inevery thing, except this wroug inference, Mr. Porrett’s 
analysis is equally correct with that of Gay-Lussac. Mr. Porrett found five times 
the quantity of red oxide cf mercury in the prussiate necessary to decompose the. 
whole acid of the prussiate,—T. - 
