MR. W. CROOKES ON REPULSION RESULTING FROM RADIATION. 
297 
under the influence of heat and during cooling, came rapidly to a maximum, and then 
soon stopped. 
322. Series 
Experiment a. 
No screen interposed. 
18 revolutions a minute. 
..-—Aluminium Cups, bright 
Fig. 24. 
Experiment b. 
Concave screened off. 
8 revolutions a minute. 
both sides. 
Experiment c. 
Convex screened off. 
8'6 revolutions a minute ; 
apparent attraction. 
323. Series II. — Aluminium Cups, blacked on the concave side. 
Experiment a. 
No screen interposed. 
11 revolutions a minute. 
Fig. 25. 
Experiment b. 
Concave screened off. 
No rotation ; slight repulsion 
only. 
Experiment c. 
Convex screened off. 
8'6 revolutions a minute ; 
apparent attraction. 
324. Series III.— Aluminium Cups, blacked on the convex side. 
Experiment a. 
No screen interposed. 
46 revolutions a minute. 
Fig. 26. 
Experiment b. 
Concave screened off. 
23 revolutions a minute. 
2 Q 
Experiment c. 
Convex screened off. 
No rotation; very slight 
repulsion. 
mdccclxxviii. 
