1819.] Royal Society. '465 



are formed in the mesenteric glands, with the exceptipn of the 

 colouring matter, which, he thinks, they acquire on exposure to 

 air in passing through the lungs. 



At this meeting the Bakerian lecture by Mr. Brancle was 

 begun : " On the Composition and Analysis of the Inflammable 

 Gaseous Compounds resulting from the destructive Distillation 

 of Coal and Oil, with some Remarks on their relative heating 

 and illuminating lowers." 



Nov. 18.— The Bakerian lecture was concluded. In the first 

 part of this lecture, the author attempted to show that no other 

 compound of carbon and hydrogen can be demonstrated to exist 

 than what is usually denominated olefiant gas, consisting of one 

 proportion of carbon and one of hydrogen ; and that what has 

 been usually termed carburetted hydrogen is in reality nothing 

 but a mixture of hydrogen and olefiant gases. In proof of this 

 opinion a series of experiments was detailed, made upon gaseous 

 products obtained from coal, oil, and other substances, and in 

 various ways, the results of all which tended to establish the 

 truth of the above opinion. 



The author advanced the supposition that many of the products 

 usually obtained by the destructive distillation of coals, . &c. 

 are of secondary formation ; that is to say, that they result from 

 the mutual action of the first formed gases at high temperatures. 

 Thus a peculiar compound of hydrogen and carbon was stated to 

 be formed by passing pure olefiant gas through a tube containing 

 red-hot charcoal. This substance was similar to tar in appear- 

 ance, but possessed the properties of a resin. So also by the 

 mutual action of sulphuretted and carburetted hydrogen, sui- 

 phuret of carbon was stated to be formed. In this part of the 

 lecture some new modes of analyzing gaseous mixtures were 

 pointed out. 



In the second section, comparative experiments were detailed 

 on the illuminating and heating powers of gases from coal and 

 oil. The general results were, that the illuminating powers of 

 olefiant, oil, and coal gases, are to one another nearly as 3, 2, and. 

 1, and that the ratio of their heating powers is nearly similar; 

 that is to say, that more heat is produced by the gas from coal 

 than by that from oil, and by the gas from oil than by olefiant 

 gas. In this part of the lecture was also strikingly illustrated by 

 experiments the great advantage obtained in point of illuminating 

 power, by forming the burners of many jets, in preference to a 

 single one, especially when the jets are made so near to one 

 another that the different flames can unite. 



The lecture was concluded by some comparative experiments 

 on the properties of terrestrial and solar light. The light pro- 

 duced by gases, even when concentrated so as to produce a 

 sensible degree of heat, was found to occasion no change in the 

 colour of muriate of silver, nor upon a mixture of chlorine and 

 hydrogen gases ; while, on the other hand, the concentrated 



Voi. XIV. N° VI. 2 



