measuring the comparative Intensities of Light. 103 
experiment, that the tallow, instead of being nearly as produc- 
tive of light in its combustion as bees wax, as it appeared to 
be when the candle was kept constantly well snuffed, was now, 
when the candle was suffered to burn with a dim light, by far 
less so than oil. 
But this is not all ; what is still more extraordinary is, that 
the very same candle, burning with a long wick, and a dim 
light, actually consumed more tallow than when, being pro- 
perly snuffed, it burnt with a clear, bright flame, and gave 
near three times as much light ! 
To be enabled to judge of the relative quantities of light 
actually produced by the candle in the two experiments, it 
will suffice to know, that in order to counterbalance this light 
at the field of the photometer, it required, in the former experi- 
ment, the consumption of 141 parts, but in the latter only the 
consumption of 64 parts of olive oil. But in the former expe- 
riment no parts, and in the latter 114 parts of tallow were 
actually found to be consumed. These parts were 8iq2ths of 
a Bavarian pound. 
From the results of all the foregoing experiments it appears, 
that the relative expence of the undermentioned inflammable 
substances, in 
the production of light, is as follows. 
Equal parts 
Bees wax. 
A good wax candle, kept well snuffed, 
and burning with a clear, bright 
in weight. 
flame, - 
100 
Tallow. 
A good tallow candle, kept well snuffed, 
and burning with a bright flame, 
The same tallow candle, burning very 
101 
dim for want of snuffing, 
229 
