192 Froceedings of the Royal Society 
tion filtered. The filtrate was rendered faintly acid with acetic 
acid, and then excess of barium nitrate added. The precipitate, 
after being washed with the minimum of cold distilled water, was 
dried in the water-bath, and found to weigh 10 "31 grs. This was 
treated with nitric acid to remove the meconate, and then ignited, 
leaving 4*36 grs. BaS04. iiieconate of barium con- 
sidered as C^H207Ba.H20 is =3 ‘37 grs. 0711407 = 8 ‘0 grs. morphia. 
(2) From a quantity of good opium the morphia and meconic acid 
were prepared with as little loss as possible. There were obtained 
627 grs. morphia hydrate and 186 grs. crystallised meconic acid. 
The proportion demanded to form the normal meconate is 262 grs. 
Experiments with other opiums were conducted as in (1), with similar 
results, the proportion of meconic acid to morphia being even less 
than that there described. 
It is evident that if the morphia salts could be made to crystallise 
from a simple extract of opium, much light would be thrown on the 
matter under discussion. AVith this end in view, 500 grs. of opium 
were exhausted with alcohol, the alcohol driven off, and the extract 
treated with water. The aqueous extract was digested with purified 
animal charcoal, and then concentrated. After some days, a small 
quantity of crystals had appeared. These consisted of morphia 
sulphate. (It should be noted here that while the neutral meconate 
readily crystallises, the acid meconate has never been obtained in 
the crystalline state.) This cannot be regarded as an altogether 
satisfactory experiment, on account of the small yield of sulphate, 
but considering that the extract is charged with substances which 
hinder crystallisation, the result is not surprising ; the use of any 
purifying agents which would cause decomposition being, of course, 
quite inadmissible. 
To thoroughly elucidate the question would require an enormous 
number of experiments ; but judging from the facts ascertained, I 
am of opinion that morphia exists in opium, partly as neutral 
sulphate and partly as acid meconate. 
3. Direct Observations of the Effect of Pressure on the Maxi- 
mum Density-Point of Water. By Professor Tait. 
