Mr Bald on the spontaneous emissions of Gas. tt' 



portion of the mixture was quite pure. For it took exactly 

 twice its volume of oxygen gas to consume it, and it left, when 

 fired by electricity, exactly its own volume of carbonic acid 

 gas. 



It is well known that carburetted hydrogen is a compound of 



Sp. gr. 

 2 volumes hydrogen gas, 0.1388 



1 volume carbon vapour, 0.4166 



0.5555, 



condensed into one volume. Hence its specific gravity is 

 0.5555. And the specific gravity of a mixture of 87.5 vo- 

 lumes carburetted hydrogen and 12.5 common air, is 0.61 09- 

 Th is gas then, which issues in such abundance, might be 

 used to fill air balloons. It would answer the purpose almost 

 as well as coal gas. Were we assured of its continuing to issue 

 always in as great abundance as at present, it might be employed 

 hghting the streets of Glasgow. But pure carburetted hydro- 

 gen gas would not give so much light as coal gas. For I 

 find that coal gas is always mixed with more or less of the 

 vapour of naphtha, which adds considerably to the brilliancy 

 of its combustion. 



Glasgow, 27th December 1828. 



Art XI. — Observations on the spontaneous emissions of in- 

 Jtammable Gas, in particular of Carburetted Hydrogen.* 

 By Robert Bald, Esq. F. R. S. E. &c. &c. Communi- 

 cated by the Author. 

 An interesting paper having been read before this Society lai^t 

 month by Dr Thomas Thomson, Regius Professor of Chemis- 

 try in Glasgow, regarding the spontaneous emission of inflam^ 

 mable gas near Bedlay, situated about seven miles N. east from 

 Glasgow, I beg leave to offer a few observations thereon, and 

 have also to state where similar phenomena have taken place. 

 The issue of gas in the rivulet at Bedlay may not have 

 been observed till lately, and perhaps it did not issue until the 



• Read before the Royal Society of Edinburgh, March 16, 1829. 



