1820.] Philosophical Transactions for 1820, Part I. 383 



Mr. Brande informs us that the specific gravity of the gas 

 from whale oil is 0-769 ; but I find that the specific gravity of > 

 oil gas is just as various as that of coal gas. I have got it as * 

 high as 1-0958, and very often as high as 0-8846. Notwithstand- i 

 ing this high specific gravity, it was not olefiant gas ; for the : 

 carbonic acid which it formed very little exceeded the volume of l 

 the gas, and the oxygen consumed was but Httle more than 

 double the volume of the inflammable gas. My gas was pro- 

 cured by passing whale oil through a red-hot iron tube. Such 

 gases are mixtures, and always contain a portion of the vapour 

 of Dippel's oil, to which much of their inflammability is owing. 



The object of the second section of this paper is to compare 

 the illuminating and heating powers of olefiant gas, oil gas, and 

 coal gas. He found that olefiant gas does not issue from a 

 small orifice with the same rapidity as oil gas. Through an 

 orifice of^th inch in diameter, 640 cubic inches of olefiant gas 

 passed in an hour, and 800 cubic inches of oil gas. This is in 

 the proportion of 4 to 5. 



To produce a light equal to 10 wax candles for an hour, the 

 consumption was as follows : 



Olefiant gas 2600 cubic inches. 



Oil gas 4875 



Coal gas 13120 



The author found, as Count Rumford had done before him, 

 that the light given out by gases was much increased when a 

 number of burning jets wei'e placed near each other. 



To raise a quart of water from 50° to 212, he found it neces- 

 sary to burn of 



Olefiant gas 870 cubic inches 



Oil gas 1300 



Coal gas 2190 



The light from an Argand's lamp with olefiant gas when con- 

 centrated by a lens raised a thermometer 4-i-° in five minutes. It 

 is well known that a mixture of equal volumes of chlorine and 

 hydrogen gas explodes when exposed to the direct rays of the 

 sun. The author produced the same effect by the light from a 

 galvanic battery ; but could not accomplish the combustion or 

 union of these gases by any other artificial light whatever. 



III. On the Elasticity of the Lungs. By James Carson, M.D. 

 — The subject of this paper, or at least one intimately connected 

 with it, has occupied the attention of the author ever since he 

 began his medical studies. In the year 1799 he received along 

 with myself the degree of Doctor of Medicine from the University 

 of Edinburgh, on which occasion he defended a very ingenious 

 thesis on the circulation of the blood. The opinions contained 

 in this thesis, which were new and important, he expanded in 



