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Probably ammonia com

of, and if the smallest proportion be taken the loss will be nearly

These results and calculations agree with those that I have before given, and with those of Dr. Henry.

The lately discovered facts in chemistry, concerning the important modifications which bodies may undergo by very slight additions or subtractions of new matter, ought to render us cautious in deciding upon the nature of the process of the electrical decomposition of ammonia.

It is possible, that the minute quantity of oxigen, which posed of hidro- appears to be separated, is not accidental, but a result of gen & nitrogen the decomposition; and if hidrogen and nitrogen be both only. oxides of the same basis, the possibility of the production of different proportions of water, in different operations, might account for the variations observed in some cases in their relative proportions; but on the whole, the idea that ammonia is decomposed into hidrogen and nitrogen alone, by elec tricity, and that the loss of weight is no more than is to be expected in processes of so delicate a kind, is, in my opinion, the most defensible view of the subject.

What is the metallic basis*

alkali?

But if ammonia be capable of decomposition into nitroof the volatile gen and hidrogen, what, it will be asked, is the nature of the matter existing in the amalgam of ammonia? what is the metallic basis of the volatile alkali? These are questions, intimately connected with the whole of the arrangements of chemistry; and they are questions, which, as our instruments of experiment now exist, it will not, I fear, be easy to solve.

Water always adheres to it.

I have stated in my former communication on the amalgam from ammonia, that, under all the common circumstances of its production, it seems to preserve a quantity of water adhering to it, which may be conceived to be sufficient to oxidate the metal, and to reproduce the ammonia.

I have tried various devices, with the hopes of being able

100 of ammonia, at the rate of 135, will give 1369 of hidrogen, weighing 3.1 grains, and 48′1 of nitrogen weighing 14:33 grains; but 184-174-1: and at the rate of 180, 133 of hidrogen weighing 301, and 47 of nitrogen, weighing 14; and 18:4— 17 — 1·4.

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to form it from ammonia in a dry state, but without suc-
cess. Neither of the amalgams of potassium, sodium, or
barium, produces it in ammoniacal gus; and when they are
heated with muriate of ammonia, unless the salt is moist,
there is no metallization of the alkali.

I have acted upon ammonia by different metallic amal-
gams negatively electrified, such as the amalgams of gold
and silver, the amalgam of zinc, and the liquid amalgam of
bismuth and lead; but in all these cases the effect was less
distinct, than when pure mercury was used.

By exposing the mercury to a cold of -20° Fahrenheit, in a close tube, I have succeeded in obtaining an amalgam in a much more solid state; yet this decomposed nearly as rapidly as the common amalgam, but it gave off much more gaseous matter; and in one instance I obtained a quantity which was nearly equal to six times its volume.

The amalgam which I have reason to believe can be made Driest amalmost free from adhering moisture, is that of potassium, gam obtained, mercury, and ammonium in a solid state. This, as I have mentioned in my former communication, decomposes very Decomposes slowly, even in contact with water, and when it has been very slowly. carefully wiped with bibulous paper, bears a considerable heat without alteration. I have lately made several new at- Attempts to tempts to distil the ammonium from it, but without When it is strongly heated in a green glass tube filled with hidrogen gas, there is always a partial regeneration of ammonia; but with this ammonia there is from to of hidrogen produced.

success.

distil ammonium from it.

As it does not seem possible to obtain an amalgam in a Ammonia, if uniform state as to adhering moisture, it is not easy to say tains 48 per an oxide, conwhat would be the exact ratio between the hidrogen and am- cent oxigen. monia produced, if no more water was present, than would

be decomposed in oxidating the basis.

But in the most re-
able to make, this

fined experiments which I have been
ratio is that of one to two; and in no instance, in which
proper precautions are taken, is it less; but under common
circumstances often more. If this result is taken as accurate,
then it would follow, that ammonia (supposing it to be an
oxide,) must contain about 48 per cent of oxigen, which,
as will be hereafter seen, will agree with the relations of the
attractions

If hidrogen be a simple substance, nitro

attractions of this alkali for acids, to those of other salifiable bases*.

If hidrogen be supposed to be a simple body, and nitrogen an oxide, then, on the hypothesis above stated, nitrogen contains gen would consist of nearly 48 of oxigen, and 34 of basis; 48 oxigen, 34 but if the opinion be adopted, that hidrogen and nitrogen are both oxides of the same metal, then the quantity of oxigen in nitrogen must be supposed less.

basis.

Phlogistic hy pothesis.

Proportions of the amalgam.

These views are the most obvious that can be formed, on the antiphlogistic hypothesis of the nature of metallic substances; but, if the facts concerning ammonia were to be reasoned upon, independently of the other general phenomena of chemical science, they perhaps might be more easily explained on the notion of nitrogen being a basis, which became alkaline by combining with one portion of hidrogen, and metallic by combining with a greater proportion.

The solution of the question concerning the quantity of matter added to the mercury in the formation of the amalgam depends upon this discussion; for, if the phlogistic view of the subject be adopted, the amalgam must be supposed to contain nearly twice as much matter, as it is conceived to contain on the hypothesis of deoxigenation. In the last Bakerian lecture I have rated the proportion at To, but this is the least quantity that can be assumed, the mercury being supposed to give off only once and a half its volume of ammonia. If the proportion stated in page 53

* Even in common air, the amalgam evolves hidrogen and ammonia, nearly in these proportions; and in one experiment, which I lately tried, there seemed to be no absorption of oxigen from the atmosphere. This circumstance appears to me in favour of the antiphlogistic view of the metallization of the volatile alkali; for if the hidrogen be supposed to be given off from the mercury, and not to arise from the decomposition of water adhering to the amalgam, it might be conceived, that, being in the nascent state, it would rapidly absorb oxigen. In my first experiments upon the amalgam, finding that common air, to which it had been exposed, gave less diminution with nitrous gas than before, I concluded naturally, that oxigen had been absorbed, but this difference might have arisen, partly at least, from the mixture of hidrogen. Whether in any case the amalgam absorbs oxigen gas, is a question for farther investigation.

be

be taken as the basis of calculation, which is the maximum that I have obtained, the amalgam would contain about To of new matter, on the antiphlogistic view, and about

on the phlogistic view.

manufactur.

I shall have occasion to recur to, and to discuss more New modes of fully these ideas, and I shall conclude this section by ing nitrous stating, that, though the researches on the décomposition acid and vola❤ tile alkali sug and composition of nitrogen, which have occupied so large gested a space in the foregoing pages, have been negative, as to the primary object, yet they may not possibly be devoid of useful applications. It does not seem improbable, that the passage of steam over hot manganese may be applied to the manufacture of nitrous acid. And there is reason to believe, that the ignition of charcoal and potash, and their exposure to water, may be advantageously applied to the production of volatile alkali, in countries where fuel is cheap.

(To be concluded in our next.)

VI.

Times of Migration of some of the Swallow Tribe, &c., near
London. In a Letter from THOMAS FORSTER, Esq.

SIR,

To Mr. NICHOLSON.

SHOULD you consider the following table, showing the periods of the earliest and latest appearance of several of the swallow tribe, &c., at Clapton, during some years, worth insertion in your Journal, it is much at your service. It may amuse some of your numerous readers, and will oblige your constant reader,

THOMAS FORSTER.

EARLIEST

Time of cer tain birds appearing and disappearing.

EARLIEST APPEARANCE.

LATEST.

1806 1807 1808 1809 1810|| 1808 1809

Hirundo rustica, Apr. May Apr. Apr. Apr. Oct. Oct.
Common swallow. 2 1 18 28 21

17 3

Hirundo urbica, Apr. May May May Apr. Oct. Oct.

Martin.

26 1 1 5

21 18 16

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Mechanical

motion in a living body subject to the laws of dead

matter:

VII.

The Croonian Lecture. On the Functions of the Heart and
Arteries. By THOMAS YOUNG, M. D. For. Sec. R. S*.

THE mechanical motions, which take place in an animal body, are regulated by the same general laws as the motions of inanimate bodies. Thus the force of gravitation acts precisely in the same manner, and in the same degree, on living as on dead matter; the laws of optics are most accurately observed by all the refractive substances belonging to the eye; and there is no case in which it can be proved, that animated bodies are exempted from any of the affections to but the vital which inanimate bodies are liable, except when the powers powers can iu of life are capable of instituting a process, calculated to stitute processes to coun- overcome those affections by others, which are comшensutract different rate to them, and which are of a contrary tendency. For

affections.

Philos. Trans. for 1809, p. 1.

example,

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