161 



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 himself jus- 

 tified 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. 



On two Metals, found in the black Powder remaining after the Solution 

 of Platina. By Smithson Tennant, Esq. F.R.S. Read June 21, 

 1804. [Phil. Trans. 1804, p. 411.] 



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 plumbago, but that it contains also 

 some other unknown metallic ingredient. Since those experiments, 

 two French chemists, Messrs. 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- 

 ferent 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 



