Gas-Burners, and on the Illuminating Power of the Gases. 3 
by Mr Brande, tending rather to encourage farther investigation 
than to arrive at the object in view. One or two observations 
of the same tendency were published last October by Dr Fyfe, 
after most of the experiments we are about to detail had been con- 
cluded. But this is all, so far as we know, that has yet been made 
public. As to the rules followed by the several gas-light compa- 
nies, it was quite evident they could not have been founded on any 
fixed or known principle. For the coal and oil gas burners of va- 
rious towns, such as London, Dublin, Edinburgh and Glasgow, 
were found, on the slightest inspection, to differ materially in prin- 
ciple from one another, not only in different places, but even also 
in the establishment of the same company ; and, when subjected to 
trial, the light given out in some of them, by equal expenditures 
of gas, proved to differ in the extravagant ratio of 10 to 14 or 
even 15. This fact alone would be enough to account for dis- 
crepancies regarding the illuminating power, even greater than 
those which have actually occurred ; and consequently showed 
the necessity of settling the proper mode of constructing burners 
for each gas, before any attempt could be made to estimate their 
relative light. 
In commencing that investigation, we were for some time em- 
barrassed by the multiplicity of points to be attended to in the 
construction of the burners, and by their reciprocal influence on 
each other. But at length a principle occurred to us, which ap- 
peared to regulate the influence of each point individually, and 
of all conjunctly. The principle now alluded to is at variance 
with that professedly acted on by the few who have turned their 
thoughts to the subject of the construction of lamps, and whose 
steps have seemingly been followed by the makers of gas-burners. 
We were therefore led to examine it thoroughly in all its rela- 
tions. 
Having made these preliminary remarks, we shall proceed at 
once to relate our experiments in the following order. 
In the first place, we shall notice the instruments employed in 
them ; then the circumstances which affect the degree of light 
emitted by the gases during combustion ; and, lastly, the results 
eventually obtained regarding their relative illuminating power. 
a 2 
