Page:Proceedings of the Royal Society of London Vol 1.djvu/501

Rh amber, when moderately heated, were attracted as acids to the pos'tive side; but when these bodies were ignited so as to admit a dense smoky ﬂame, the_carbonaceonsc matter was drawn, like that of other resinous bodies and camphor, to the negative ball.

The majority of these instances, says the author, serve well to illustrate the inherent electrical states of different species of matter, and give a further proof of the identity of common and voltaic electricity, and especially the attraction of the fumes of the phosphoric and benzoic acids to one side, and of the fumes produced by the combustion of potassium and camphor to the other.

But there are some phenomena that did not turn out as might have been expected. The combustion of carburetted hydrogen, for instance, gives rise to the p'roduction of water and of carbonic acid; but its ﬂame is attracted by the negative surface. It is conceived, however, that this direction may be given to the ﬂame by its carbo- naceous contents rather than by the products of its combustion.

Mr. Brande is of opinion that these experiments may suggest a fair explanation of the phenomena presented by those bodies that are termed unipolar by Mr. Erman, because when connected with one or other extremity of the voltaic battery, they transmit the in- ﬂuence of only one species of electricity. The ﬂame, for instance, of oil or of wax must be considered as consisting chieﬂy of these bodies in a state of vapour; and as their natural electricity is positive, they will have no tendency to destroy that of a positive pole with which they are connected, and the gold leaves of an electrometer will continue to diverge; but when they are applied to a negative pole, their inherent positive electricity will neutralize that of the battery to which they are united, and the gold leaves will in con- sequence collapse.

Since the date of those attempts of the author to decompose ﬂuorine, of which an account has already been printed in our Transactions, and from which he inferred that pure liquid ﬂuoric acid consisted of hydrogen united to a base which he had not then been able to procure in a separate form, but which is detached from the hydrogen by various metals, he has made many experiments that in his opinion tend to conﬁrm this idea, though all his attempts to effect the actual decomposition have been unsuccessful.

Fluate of lead, which, according to the author’s view of its constitution, consists of lead united to the peculiar ﬂuoric principle, is not decomposed by dry ammonia; but by liquid ammonia it yields oxide of lead, in consequence of the decomposition of water which gives oxygen to the lead, and hydrogen to the acid which now enters into the composition of ﬂuate of ammonia.