SALE OF POISONS. 
719 
' force which enables a piece of box-wood charcoal, for example, to absorb 95 
times its volume of ammoniacal gas, causes the charcoal, in the midst of a hot 
solution of vapour to absorb vapour, and under the continued action of heat to 
give it out again in a constant, never-ceasing flow. 
Indeed, what is remarkable is the permanent action of these porous bodies. 
I have tried the same piece of charcoal or of coke, in boiling liquids, over and 
over again for weeks together, and never found the vapour-giving action to 
flag. I have boiled these porous bodies in strong acids, and washed them in 
alkalies, and made them in all respects chemically clean, without at all inter- 
' fering with their vapour-separating action in boiling liquids. They do not act as 
nuclei in separating salt from solution, if boiled up with it and allowed to cool 
in it; their peculiar function is to separate vapour from liquids at or near the 
boiling-point, and this they do by their capillarity. I have in this flask a 
bundle of glass capillary tubes, united like a faggot by means of a thread in the 
middle. This acts vigorously in separating vapour from the liquid at the boil¬ 
ing-point, and even after the lamp has been removed from under the flask the 
tubes continue for some time to discharge vapour from their ends. 
Among the charcoals, the most efficient as a vapour nucleus is charcoal from 
cocoa-nut shell. This is very dense, and sinks below the surface of liquids 
denser than water, which is a great advantage. 
It will, I think, be worth your while to come up after the lecture and watch 
closely this large flask of water containing some pieces of cocoa-nut-shell char¬ 
coal. The vapour passes off from each piece in perfect torrents, and there are 
these two remarkable advantages connected with the action, namely, bumping 
is entirely prevented, and the amount of the distillate is largely increased, in 
some cases as much as from 30 to 50 per cent, with the same amount of heat, 
in the same time as compared with the process without the use of the char¬ 
coal. 
For example: methylated spirits of wine, boiling at 171° F., was distilled in 
a glass retort. The distillate collected in five minutes weighed 244 grains. 
Three or four fragments of charcoal, partly box-wood and partly cocoa-nut 
shell, weighing only 20 grains, were added to the retort. The distillate, in five 
minutes, was now 325 grains. The ratio of the results is 100 : 133*2 ; with 
20 grains of pumice-stone the results were as 100 : 121*7 ; with 20 grains of 
meerschaum, as 100 : 112; and with 20 grains of coke, as 100 : 107 46. 
But these results are understated; for the retort contained some porous 
specks of iron or charcoal, which get attached to most glass vessels during the 
process of manufacture, and which act as powerful nuclei in separating vapour 
from boiling liquids; indeed, were it not for these accidental impurities, many 
a chemical operation must fail from excessive bumping. 
But as I promised to make this a short lecture, I must conclude. You see 
that there is a harmony of action in the behaviour of nuclei, with regard to 
gaseous, saline, and vaporous solutions, and from this action we get a clear 
view of the functions of nuclei ; and also get rid of much speculation as to 
u molecular action ” and the “ mysterious action of the air,” which some ob¬ 
servers indulge in when treating of supersaturated solutions. 
SALE OF POISONS. 
TO THE EDITORS OF THE PHARMACEUTICAL JOURNAL. 
Gentlemen,—The practice adopted by chemists throughout the country, in 
registering and labelling poisons, is so widely different that I venture to offer a 
few suggestions on the subject. With regard to many preparations containing 
