Gas-Burners } and on the Illuminating Power of the Gases . SI 
proportion, indeed, to the variations in that of coal-gas. This is evident from 
the following table. 
Gas made with great care by Dr Henry, - - - , - 464 
Ditto, - 590 
Ditto, - - 758 
Ditto, used by Mr Brande in his experiments, - - - - 769 
Gas made at Mr Mylne’s Brass-Foundry, Edinburgh, and used by Mr 
Leslie in his experiments, - - 674 
Ditto, - - - 810 
Ditto, - - - - 943 
Ditto made from cod-oil, at Taylor and Martineau’s, - 906 
Ditto used by Mr Dewey in his experiments, - 939 
Ditto Messrs Phillips and Faraday, - 966 
The worst oil-gas we have examined, - 660 
Gas made at Mr Mylne’s from whale-oil, and used in some of our expe- 
riments, ------- 820 
Ditto, - 944 
Gas made from whale-oil, at Mr Ranken’s Glass Manufactory, Edin- 
burgh, and used in our experiments, - - - 778 
Ditto, - - - - 968 
Ditto, - - - 1110 
The same gas, after standing a day over its own volume of fresh-water, 1050 
The last of these has a higher specific gravity than any oil-gas hitherto 
noticed publicly. We may mention, that there is no reason for doubting the 
accuracy of the observation, as it was quite conformable with the results ob- 
tained respecting the expenditure of the gas, its illuminating power, and the 
diminution it sustained from the action of chlorine *. 
While the method of manufacturing coal-gas is so well understood, and the 
process for making oil-gas so unsettled, while the quality of the former is so 
uniform, and that of the latter so variable, we apprehend it is scarcely time to 
say what is their relative illuminating power. Whatever we may now state, 
therefore, on this subject, must be understood as applying only to gases of 
certain specific gravities, not to oil and coal gas abstractly. 
The following is a table of the chief results that have been hitherto ob» 
tained on this subject ; 
Mr Brande, 
1 
to 
2i 
Mr Dewey, 
1 to 3| 
Mr Nielson, 
1 to 2, or 
n 
Dr Fyfe, 
1 to 14 
Messrs Herapath and 
Rootsey, 
1 
to 
2 
Mr Leslie, 
Mr Dalton, 
1 to 14 
1 to 2| 
Messrs Phillips and 
'Faraday, 
1 
to 
31 
Mr Ricardo, 
1 to 4 
All of these proportions were procured by pkotometrical measurement, 
with the exception of Ricardo’s, which was derived from a comparison of the 
quantity of each gas manufactured by the London Companies, with the num- 
ber of lights supplied by them. 
* It contained 46 per cent of gas condensible by chlorine. 
