the Petroleum of Rangoon. 121 



paper, and immediately subjected to strong pressure between 

 folds of blotting paper. The yellow colouring matter, which all re- 

 mained in solution in the ether after it cooled, was thus, in a great 

 measure, imbibed by the paper ; and the crystalline matter was 

 procured in a state of purity by repeating this process twice. 



On first procuring this crystalline substance, I considered it 

 as the same with the naphthaline procured not long ago from coal- 

 tar by Mr Kidd, as related in his paper in the Philosophical 

 Transactions for 1821. This opinion I was led to form from the 

 appearance of the crystals, the nature of the substance which 

 yields them, and the process of distillation by which they were 

 procured. 



On a careful examination, however, I find that the crystal- 

 line principle of petroleum differs materally from that of coal-tar, 

 as well as from every other known body ; and I shall therefore 

 beg leave to denominate it Petroline, according to the analogy 

 suggested by the name of Mr Kidd's crystalline principle. 



As procured by the process described above, petroline forms 

 foliaceous masses of small crystals of snowy whiteness, and bright 

 pearly lustre. It is somewhat unctuous, and has a naphthous 

 odour, which becomes very faint on exposure for some time to 

 the air, and is removed altogether by boiling in alcohol. It 

 fuses at 135° into a transparent, limpid, colourless fluid; but 

 softens ten degrees lower. From a state of fusion it concretes 

 on cooling into a translucent brittle mass, like wax, the density 

 of which is 909 at 60° Fahr. At a temperature intermediate 

 between the boiling point of water and a low red heat, the fluid 

 boils, and distillation takes place. The greater part of the petro- 

 line condenses in the form of a fluid, which becomes on cooling 

 a translucent waxy mass, with its original properties. But owing 

 to the elevated temperature required for its distillation, a part 

 is decomposed, a little charcoal is left behind, and a small quan- 

 tity of inflammable gas passes over with the undecomposed sufr- 



vol. xiii. part j. <a 



