Page:Proceedings of the Royal Society of London Vol 1.djvu/181

Rh that of the bitumen called Asphaltum; the resin being in the largest proportion, 100 grains affording 55 of resin, and 44 of asphaltum. Thus we have an instance of a substance found under circumstances which constitute a. fossil, although the character of it partly apper- tain to the vegetable and partly to the mineral kingdom

In the concluding section the author enters into an inquiry on the action of alcohol on resins and bitumens. Its power of dissolving the former is well known; but, contrary to the adopted opinion, he found that it also acted on bitumen, though indeed in a slight degree. His chief object was to ascertain whether a small portion of resin is con- tained in any of the bitumens, or, if not, to determine the nature of the substance which can be separated, although very sparingly, from, those substances by digestion in alcohol. The results prove that the small portion which can be extracted from bitumen by digestion with alcohol is petroleum.

From a general view of the subject, the author thinks himselfjus- titled in asserting, that in bitumens the process of transformation ap- pears to have been completed; whereas in the Bovey coal, and espe- cially in the substance which accompanies it. Nature seems to have performed only half of her work, and, from some unknown cause, to have stopped in the middle of her operations. By this circumstance, however, much light is thrown on the history of bituminous sub- stances; and the opinion that they owe their origin to the organized kingdoms of nature, and especially to the vegetable, which hitherto had been supported only by presumptive proofs, seems now to re- ceive-a full conﬁrmation, although the causes which operate these changes on vegetable bodies are as yet undiscovered.

From a few experiments the .author made in the course of last summer on this powder, he concluded, that it does not, as was gene- rally believed, consist chieﬂy of plumhago, but that it contains also some other unknown metallic ingredient. Since those experiments, two French chemists, Nlessrs. Descotils and Vauquelin, having like: wise examined that substance, found the same new metal; but nei- ther of them observed that it contains moreover another metal dif‘ férent from any hitherto known.

The black powder used in the process, which is the subject of this paper, was obtained from platina carefully separated from all extra— neous particles; so that the above ingredients, if found, must have been contained in that metal.

The ﬁrst set of experiments relates to the effects produced by this powder when alloyed with other metals. It combines readily with lead; but the compound, even when the lead greatly predominates, is not very fusible. With bismuth, zinc, and tin, the effects are nearly similar; but with copper, a strong heat produces a much more