Chemistry and Physics. 235 
using vanes of mica previously rendered anhydrous by ignition 
and working with hydrogen, he has thus succeeded in constructing 
a radiometer of such sensibility that it moved under the sole influ- 
*s rays. The results of Finkener on the point of 
otherwise like condinieng nan one 1 a large bulb and this 
also has been fully realized by Mr. Crookes.+ Quite rege 
Stoney and Mossf have published some preliminary results o 
investigation, in which they propose to compare the i Foe 
and wi 
and under varying conditions "of tension, ascent te. 
Investigation was begun soon after the publication of Stoney’s 
original communication to the Phil. ee , March, 1876, and is not 
yet completed. Th ive a description of their apparatus, and 
they call the reaction exerted between the cooler and heater in 
the radiometer and all similar instruments, “ Crookes’ Force.” 
sure, 
sensible at a distance of at lea n mailion 
rfac 
pent being rag of ia rota plate, the siemapiee he of t 
surfaces must be essentially the same. Such effects Boies 
ta studied both by Crookes§ and by Zéllner. 
Rok is ites noe in favor of the view of the subject _ presented 
no psc a new eu rip or exaggerate an old = pe 
* Annales de Chimie et Physique, V, x, 396, pa jdt a Beiblatter, i, 165. 
pEehiaten i, 318, No. 6; also Proc. Roy. 'Soe., 
Beiblatter, i, 169. 1 Pogg. Ann., clx, 169. 
