1815.) Scientific Intelligence. A469 
moderate heat. Care must be taken that none of the muriatic acid 
passes over, and a tube filled with dry muriate of lime. should. be 
iuted to the beak of the retort, in order to absorb all the moisture, 
The receiver should be surrounded with ice. 
Prussic acid, thus prepared, is a colourless liquid, having a 
strong odour, and a taste at first cooling, then hot, and. violently 
poisonous. Its specific gravity at 45° is 0°7058; at 64° it is 0°6969. 
It boils at 80°, and congeals at about 5°. At that temperature it 
crystallizes regularly. The cold which it produces when converted 
into vapour, is sufficient, even in summer, to congeal it. The 
specific gravity of its vapour is 0°9360. This vapour was mixed 
with oxygen gas at 72°, and detonated in a Volta’s eudiometer. 
100 measures of the gas consumed 125 measures of oxygen; 100 
measures of carbonic acid were formed, and there remained 50 
measures of azotic gas. 100 of the oxygen went to the formation 
of carbonic acid, and 25 to that of water; hence the hydrogen 
present, if in the state of gas, would have amounted to 50 mea- 
sures. It is evident from this analysis, that prussic’ acid is com- 
posed of 
Carbon ...... diese veces Oi dah 2 volume 
Fiydrogaa’s 2.008. FAs. tel er OS 
Azote eevee oe eevee eer eves eeeeresn 0°5 
20 
condensed into one volume. Or by weight of 
Carbamn sid 165 abies, 44:39 xe sistas siete 2 atoms 
Azote eee e@reevee S174 ereeervee 1 
Eiydrogent i150 5 670 8°90 »srifos een 1 
100-00 
Prussic acid cannot be kept. It is decomposed spontaneously, 
and converted into prussiate of ammonia and a black matter com- 
posed of carbon and azote. Phosphorus and iodine may be sub- 
limed in it without alteration, Sulphur combines with it. Potas- 
sium put into the vapour of prussic acid absorbs it, while a quantity 
of hydrogen is disengaged equal to half the volume of the prussic 
vapour. The potassium is converted intoa yellow substance, 
soluble in water, and converted by this solution into prussiate of 
potash. From this result it is obvious, that prussic acid, like 
Miuriatic acid and hydriodic acid, is composed of a radicle com- 
bined with hydrogen. This radicle is obviously a compound of 
two atoms of carbon and one atom of azote. ‘This radicle may be 
obtained in a separate state. Like chlorine and iodine it unites 
with many bodies; hence prussic acid, like muriatic and bydriodic 
acids, is composed of equal volumes of a radicle and hydrogen gas 
united together, without any diminution of bulk, Gay-Lussac has 
given the name of cyanogen to the radicle, and of hydrocyanic 
“ettd to what was formerly called prussic acid. . 
