130 
MR. W. CROOKES OK REPULSION RESULTING FROM RADIATION. 
Fie. 
476. An experiment tried three years ago with the bar photometer (described in 
Part III. of this research, par. 135'"') hears so closely on these results that I condense 
the following description from my note book. 
The bulb was filled with dry ah’ at atmospheric pressure, and the movement of the 
bar being observed by an index ray of light on a graduated scale, a candle was 
uncovered at different distances. 
With the candie six inches from the bulb, the index first showed repulsion 4 divisions, 
and then strong attraction, going cphte off the scale, more than 500 divisions. 
* Phil. Trans,, 1876, Yol. 166, part II., p. 333, 
