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But if we are in a state to perceive only a part, an un~ 
Known fraction of that light, which luminous bodies shed, 
how can it be conceived that we can in any case measure it 
completely, and compare it with heat or any other thing ? 
All that we can do is, to compare the intensity of one 
light visible to us, with the intensity of another equally vi¬ 
sible, in order to determine their relative power, to illumi¬ 
nate the objects around us; and what interests us particu¬ 
larly in this research, is doubtless to discover the means of 
arranging matters in such a manner, that the substances 
which afford light in their combustion shall furnish that 
which is useful to us in the greatest possible abundance. 
It is in the application of our discoveries to perfect the 
art of illumination, that their importance will appear with 
the greatest eclat. 
We have sought a long time the means of increasing the 
light of lamps in order to render them serviceable in light¬ 
houses, on coasts, harbors, and for other purposes, but 
without success. We have used lamps with a double cur¬ 
rent of air, of large dimensions, but we find that they gave 
less light than the same kind of lamps of the ordinary di¬ 
mensions. 
I believe I was the first who united together a number of 
lamp sockets with a double current of air in the centre of 
large balloons of gauze (de grands balons de gaze) for the 
purpose of illuminating large apartments. This invention 
has been found useful; but if I am not mistaken it will 
soon give place to one much more simple, economical, and 
which ought to produce a more beautiful effect. 
Since I have better understood the nature of light, I have 
discovered the means of increasing its intensity in a focus 
almost at pleasure. I have just finished a lamp of a con¬ 
struction extremely simple, which, with four flat wicks, pla¬ 
ced one by the side of the other at the distance of about two 
lines, separated in the wick-holes, to give passage to the 
air, affords nix times more light than an ordinary lamp with 
