Page:Proceedings of the Royal Society of London Vol 1.djvu/144

Rh cal purposes, the author owns that other methods of forming it, be- sides those here suggested, might be contrived : but the general pro; blem, he says, is to combine, in the most intimate manner possible, the greatest quantity of mercury with a given quantity of platina. And he adds, that the principal difﬁculty in resolving the problem vn'll be to unite such a portion of mercury that the speciﬁc gravity of the compound may not exceed 12; and that it may be soluble in nitric acid. ‘

In the course of this inquiry, many instances have occurred which show how much we have yet to learn concerning the nature of mer- cury and platina. Of the former, we know that it is perpetually varying; and that certain solutions of it will frequently change their state in a few hours: and as to the latter, we are still more in the dark concerning its principal properties. A considerable part of the present paper is taken up in describing some experiments respecting these metals, from which we learn that platina will combine with oxygen, and form a true oxide; that the afﬁnities of platina diﬁer much from what has generally been stated in the tables ; and that, in general, the whole doctrine of chemical afﬁnities still offers a ﬁeld for much investigation. The affinities of metals, which are here ex- perimentally demonstrated in several instances, will, no doubt, serve to put us upon our guard concerning the admission of new simple metals, which, on close examination, will often, as in the present case of the palladium, turn out to be combinations of so close a nature as not to be easily decomposed. A great obstacle to the discovery of this de- ception is, no doubt, the little dependence that is to be placed on speciﬁc gravities; since, as we have seen above, a contrary anomaly to that which operates upon platina and mercury may take place in other alloys, which in some cases become as much heavier than the mean as the palladium becomes lighter. In a word, the principal task of modern chemists seems to be to simplify and reduce the im- mense number of supposed elements; and, by a close observation of nature, to learn from what a small store of primitive materials all that we behold and wonder at has been originally created.

On the 9th of July 1801, this frigate sailed from Sheerness harhour with a strong favourable wind. In about thirty minutes she went downbythehead, and in less than four minutes more she sunk entirely, twenty-two of the crew having perished by the fatal accident, which is ascribed to the hawse—holes being extremelylarge, low, and carelessly left open; so that by the crowd of sail the ship bore, they were pressed under water, by which means she ﬁlled imperceptibly, and sunk before any preventive means could be applied.