immovable over its center during the whole operation. The candle was
allowed to get itself into a normal state of burning, and then the wick
was aligned, as shown in the photographs Nos. 1 and 2, after which it was
left to itself.

[Illustration: VARIATION IN PHOTOMETRICAL STANDARDS.]

With these photographs (represented in the cuts) I beg to hand you
full-sized drawings of the scales of a 100 inch Evans and a 60 inch
Letheby photometer, in order to give your readers an opportunity of
estimating for themselves the effect which such variations from the true
distance between the standard light and that to be measured, as shown in
this series of photographs, must exercise on photometrical observations
made by the aid of either of the instruments named.

W. SUGG.

* * * * *




BLEACHING OR DYEING-YARNS AND GOODS IN VACUO.


[Illustration]

Many attempts have been made to facilitate the penetration of textile
fabrics by the dyeing and bleaching solutions, with which they require to
be treated, by carrying out the treatment in vacuo, _i.e._, in such