92 
BRUNxVER ON THE BAROMETER. 
solving them in alcohol, and by animal char- 
coal ; lastly, in order to have it perfectly 
pure, fit should bedisrsolved in ether and eva- 
porated spontaneously. 
The ammoniacal liquid is concentrated to 
the consistence of liquid honey, and agitated 
strongly with etlier. 'J he liquid dissolves tlie 
meconine. By distilling the ether this sub- 
stance remains ; it is purified by solution in 
water and charcoal, and when the aqueous 
solution is evaporated, white crystals of long 
prismatic needles make their appearance. 
When we wish to obtain the other sub- 
stances, all these processes are not necessary, 
it is sufficient after having precipitated the 
infusion ofopinm by muriate of lime, to con- 
centrate the liquid and treat it directly with 
ether. By this means, rather more meconine 
is olitained. When the ether has ceased to 
act, the black liquid thus taken up is decant- 
ed and exposed in a cool place where it 
assumes a crystalline form ; it is then ex* 
pressed and treated with boiling alcohol. 
'I'he product dissolved in this case is Narceine. 
But it is firoper to state, that as this substance 
is not soluble in ether, and as the black' sub- 
slances which accompany it are soluble in 
alcoliol, there are some difficulties accom- 
panying the process for obtaining it ; it is 
always procured pure by em ploying boiling 
water. No notice is here taken of meconic 
acid, which combines with the lime, and 
forms himeconate of lime, because Robiquet 
has sufficiently explained tlie method of ob- 
taining it. 
Wiili regard to the double muriate of mor- 
phine and codeine, it is dissolved several times 
in boiling water, passing it through charcoal 
in order to decolourize it, or decom[)osing it 
by ammonia, which precipitates almost all 
the moriihine, and leaves in the solution the 
codeine, with a little morphine combined with 
the muriatic acid, constituting the salt of 
Gregory. The morphine is purified by the 
usual means. 
'The solution of the triple salt is evaporated 
until it appears about to crystallize; then 
caiK^tic potash is added in excess, which pre- 
cipitates the codeine and retains tlie morphine 
in solution ; the solution is then heated 
slightly, and allowed to stand for a day. The 
codeine, which at first appeared as an oil, 
crystallizes. It may be purified by solution 
in ether or alcohol. The former is prefera- 
ble ; because, if it contains morphine, this 
will be a direct method of separating it. 
From 40 lbs. of opium Couerbe obtained by 
this process, 
1 oz. of meconine 
,, codeine 
f ,, narceine 
1 ,, thebaine 
50 ,, morphine 
He did not extract narcotine, which exists 
in the refuse of opium and is well known. 
These substances present the following ap- 
pearances when agitated with sulphuric acid 
containing a little nitric acid. Morphine gives 
a brownish colour. Codeine, a green colour. 
Thebaine a yellow rose-colour. Narcotine, a 
blood-red colour Meconine, a turmeric yellow, 
then a red colour. Narceine, a chocolate 
colour. 
THEBAINE crystallizes from an ethereal 
solution, in flat rhomboidal prisms, with a 
fine lustre, and white colour. It is strongly 
alkaline. 
When exposed to the temperature of 266® 
it fuses, and becomes solid at 230®. Narco- 
tine fuses at 338° and solidified at 266°. 
Codeine fuses at 302, and meconine at 194°. 
The strong acids convert thebaine into 
recin, and when diluted form crystallizable 
salts. The following results were obtained 
by Couerbe : — 
Carbon. Oxygen. Hydrogen. Azote. 
Narceine, . .5G'818 3T900 6-626 4-656 
Thebaine,.. 71-976 15-279 6.460 6-385 
Codeine 72-846 14 775 7-148 5-231 
The Paramorphine of Pelletier was obtain- 
ed l)y 'riiiboumei y by treating the- infusion of 
opium with slacked lime. He obtained by 
this means a clear liquid, and a precipitate 
containing much lime, which was treated 
with alcohol, and the solution gave, instead 
of mor{)hine, this new substance, which ap- 
pears the same as tlie thebaine of Couerbe. 
The proportion of morphine in opium, 
Couerbe states may be determined in the 
course of two hours, by boiling the infusion 
of opium with an excess of lime, and passing 
the solution through a filter. If an acid he 
added, taking care not to add in excess, 
morphine precipitates. 
DESCRIPTION OF A BAROMETER, 
By C. Brunner, of Bern. 
Poggendorff's Annalen der Fhysik und 
Chimie. 
Band, xxxiv. 1835. 
The author observes that the atmospheri- 
cal pressure may be measured in two differ- 
ent ways, either by observing the height of a 
liquid column contained in a tube, the up- 
per part of whicli is deprived of air, and the 
lower extremity is expo-ed to the excess of the 
atmosphere, as in the common barometer, 
01 by the volume wliich a gas occupies in a 
closed vessel, when the latter is completely 
elastic, or the act of enclosing the gas in the 
vessel is effected without perceptible resistance. 
4'he apparatus of Varignon, described in 
1705 ; tlie sympiesometer of A die the baroskope 
of Prechll, and the differential barometer of 
August, are examples of the latter. Fie then 
proceeds to describe an instrument which he 
has constructed upon similar principles, and 
which may be termed the volume barometer. 
The peculiarities of his contrivance depend 
upon having the surface of the liquid in the 
tube, and that surrounding it, on a level : 
that the liquid shall be of such a nature as 
to have no perceptible tension at common 
temperatures: that it shall not perceptibly 
adhere to the glass, lest a portion remain 
hanging in the tube, and the enclosed volume 
of air be undervalued : that all the observa- 
tions be taken at the same temperature, or that 
the influence of the temperature upon the 
enclosed air be taken into account. 
He recommends it as being very convenient 
for making the necessary reductions for gas 
mixtures. 
