102 
Count Romford's Account of a Method of 
and the light of the lamp was, during the whole time, kept 
in the most exact equilibrium with the light of the candle ; 
which was easily done by occasionally drawing out, a little 
more or less, one or more of its five equal wicks,- These wicks, 
which were placed in a right line perpendicular to a line drawn 
from the middle wick to the middle of the field of the photo- 
meter, were about of an inch in diameter each, and i of an 
inch from each other, and when they were lighted, their flames 
united into one broad, thin, and very clear, white flame, with- 
out the least appearance of smoke. 
In order to ascertain the relative consumption of olive oil 
and rape oil, in the production of light, two lamps, like that 
just described, were made use of; and the experiment being 
made with all possible care, the consumption of olive oil ap- 
peared to be to that of rape oil, in the production of the same 
quantity of light, as 129 is to 125. 
The experiment being afterwards repeated with olive oil 
and very pure linseed oil, the consumption of olive oil appeared 
to be to that of the linseed oil as 129 to 120. 
The experiment being twice made with olive oil, and with a 
tallow candle ; once when the candle, by being often snuffed, 
was made to burn constantly with the greatest possible bril- 
liancy, and once when it was suffered to burn the whole time 
with J very dim light, owing to the want of snuffing, the re- 
sults of these experiments were very remarkable. 
When the candle burnt with a clear, bright flame, the con- 
sumption of the olive oil was to the consumption of the tallow 
as 129 is to 101 ; but when the candle burnt with a dim light, 
the consumption of the olive oil was to the consumption of the 
tallow as 129 is to 229. So that it appeared from this last 
