284 Scientific Intelligence. 
gas in these two cases is burnt under very different conditions, while in 
Mr. Storer’s experiments, and those which I have tried, the gas was 
burnt under precisely the same circumstances whether a shade was in- 
terposed or not, the only difference being in the substances through 
which the light was transmitted. 
conducted my experiments in the following manner :—In order to 
avoid the trouble and inaccuracy arising from the use of a candle, I em- 
ployed a gas-light as the standard of comparison throughout the trials 
of all the shades. This could easily be done, asin the blackened experi- 
ment chamber of the Liverpool United Gas Light Co., there is a dupli- 
cate set of apparatus, two governors, metres, burners, &c., being fixed at 
qual 
lear 
reading on the photometer staff was then found to be 1118 
side of the centre of the staff nearest A, or, in other words, the propor- 
: ined. 
After all the shades had been examined, the lights were again com- 
per hour. The gas was taken from the strect mains. ; 
By using a standard light of unvarying intensity, all the errors ro 
mption of a d 
] 
candle are avol 
The divisions on the photometer staff do not necessarily represeD® 
candles, but the proportion that one light under examination, bears . 
the other, when one of them is taken as uni 
I may observe that the single experiment made with a sheet of ree! 
mon window glass was tried simply to confitm the result obtained PY 
the globe of clear glass, : 
The distance at which the glass is placed from the light does not seem 
in the slightest degree to affect the amount of light transmitted through 
it. I am glad to find that my own experiments on this point are 00 
tirely confirmed by Mr. Storer’s statement. Wuiam Kiva. 
Liverpool United Gas Light Co., Dec, 28, 1860. 
Nore sy Mr. Storer. 
: 
