Measures of

Measures of Measures of Diminution inflammable Gas Oxygen con- carbonic Acid

of

This coincidence is so exact, that I do not hesitate to conclude that the inflammable gas, which was the subject of experiment, was in reality a mixture of 70 parts of carbonic oxyd, and 30 of carbureted hydrogen. The specific gravity, indeed, which was 0.908, does not exactly agree with the specific gravity of such a mixture; for 2 measures of carbonic oxyd, and one measure of carbureted hydrogen, ought to form a mixture of the specific gravity 0.849, provided the specific gravity of carbonic oxyd be 0.956, and that of carbureted hydrogen 0.600; but this objection cannot be admitted to be of much weight, till the specific gravity of pure carbureted hydrogen be ascertained with more accuracy than has hitherto been done.

The results contained in the preceding table enable us to determine the composition of this inflammable air with considerable precision; for 100 cubic inches of it require 91 inches of oxygen, and form 93 cubic inches of carbonic acid. But it is known that carbonic acid gas requires for its formation a quantity of oxygen gas equal to its own bulk: therefore, to form 93 inches of it, 93 inches of oxygen gas must have been employed; but only 91 were mixed with the gas: therefore the gas itself must have furnished a quantity of oxygen, equivalent

equivalent to the bulk of two cubic inches, besides all the carbon contained in 93 inches of carbonic acid.

This carbon amounts in weight to......12.09 grains. Two cubic inches of oxygen weigh

Total ............

68

.12.77

But as 100 cubic inches of the gas weigh 28.15 grains, it is obvious that besides the 12.77 grains which it furnished to the carbonic acid, it must have contained 15.38 grains of additional matter; but as the only two products were carbonic acid and water, it is plain that the whole of this additional matter must, by the explosion, have been converted into water. Its constituents of course must have been

13.19 oxygen.

2.19 hydrogen.

15.38

Adding this to the 12.77 grains formerly obtained, we get the composition of the gas as follows:

which reduced to 100 parts, becomes

Oxygen.................... 49.27

5. The residue which remained in the retort, after the distillation was over, was a grey powder, not unlike pounded clay slate. To ascertain its constituents, it was dissolved in diluted nitric acid with the necessary precautions; the loss of weight indicated the quantity of carbonic acid. The charcoal remaining undissolved, was allowed to subside, carefully washed by repeated affusions of water, and then dried in a glass or porcelain capsule. It must not be separated by the filter, for it adheres so obstinately that it cannot be taken off the paper, nor weighed. The nitric acid solution was precipitated by carbonate of soda, and the carbonate of lime obtained was violently heated in a platinum crucible. What remained was pure lime.

4

On the Cultivation of the Poppy for extracting the Oil.

By Dr, COGAN.

From the LETTERS and PAPERS of the BATH and WEST
of ENGLAND SOCIETY.

ALTHOUGH

LTHOUGH the experiment related in the following letter was made previous to the insertion of the article, concerning the cultivation of the poppy; in our tenth volume, it is very satisfactory to find, that an English gentleman of respectability has paid some attention to the subject, and proposes to make farther experiments; the result of which must be beneficial, as it will increase our stock of facts, and thus become applicable to some valuable purpose.

Extract of a Letter addressed to Dr. COGAN, by
EBENEZER HOLLICH, Esq.

"When I passed through Flanders in the summer of
1802, I saw several fields of poppies, and learnt that
they were grown for the purpose of expressing oil from
their seed for food; and that they fed cattle with the
refuse or cake. I also learnt that they considered the
oils much inferior to that made from olives. I well re-
member, at the table d'hote at Lisle, hearing a gentle-
man say, throwing the cruet from him, Ah! it is
poppy.' I however, wishing to try it in England,
brought a small quantity of the seed over; and on the

See page 106 of the present volume of this work.

first of April, 1803, (I think rather too late in the year,) sowed it. I grew enough to enable me to ascertain nearly how much oil a bushel of it will produce. I tried 3 bushels, weighing 1 cwt. 2 qrs. and it produced 6 gallons 2 lbs. of oil, (7 lbs. to a gallon,) and 3 qrs. 25 lbs. of cake; of course 12 lbs. were wasted in the working. It was worked three times over; the first run cold 17 lbs.; the second run cold 19 lbs.; the third run 11 lbs. was heated. This being so small a quantity, it cannot be quite accurate; nor were we able to have the mill so clean from rape, which it had been just working, as to give it a fair trial. But I am inclined to think, both from this specimen, and from a sample of that oil which my very ingenious friend Mr. Pugh, of Rouen, gave me, when I was there, that it by no means is equal to fine olive oil for eating; but I question if it.might not supply the place of Gallipoli oil, which would be a great acquisition to our manufactories, especially in time of war. And I mean next year to sow a field lately broke up from sainfoin, of about three acres, with it; by which I hope to get seed enough to ascertain its use, and how far it may be worth while to grow it in this country. You will see that my account of the oil produced from a given quantity of the seed differs much from that of Mr. Van Eys. If the sacks mentioned in your paper upon the cultivation of the poppy be four bushels each, I drew much more oil per bushel than he got. As to the cakes, Mr. Eys has given no intimation of their quantity, that is, their weight.

"I found a great difficulty in harvesting the seed. I think we plucked it up, set it upright like beans in the field, and let it stand for some days; and then brought