“ NEW FORCE ” OF M. J. THORE. 
455 
No. of 
experiment. 
Material of pillar. 
Maximum 
speed of one 
revolution. 
No. of 
revolutions. 
Exciting agent. 
1 
Polished ivory. 
seconds. 
12 
4-5 
Face 
2 
Polished ebonite. 
16 
3-50 
11 
3 
Boxwood wedge, edge to cylinder . 
41 
3-25 
11 
4 
„ „ flat side to cylinder . 
32 
3-00 
11 
5 
Polished brass tube. 
39 
3-0 
11 
6 
Polished square brass rod, flat side to 
24 
3-5 
11 
7 
cylinder 
Polished square brass rod, edge to 
21 
4-0 
11 
cylinder 
Instead of using the radiation from the face as the active agent, I now employed the 
four-ounce flask, lampblacked outside, full of boiling water. This was put 2 inches 
from the cylinder and pillar, and the following experiments were tried with it:— 
No. of 
experiment. 
Material of pillar. 
Maximum 
speed of one 
revolution. 
No. of 
revolutions. 
Exciting agent. 
8 
Polished ivory. 
seconds. 
18 
4-25 
Hot water 
9 
Polished brass tube. 
1-0 
11 
In these experiments a point which struck me as being remarkable was the greater 
action which took place when I held my face 8 inches off the cylinder than when the 
exciting agent was a lampblacked flask full of boiling water. M, Thore says that 
heat is without action, and that the origin of the force appears to lie in the observer 
himself. At first sight these results appear to favour this view. It must, however, 
be remembered that the circumstances are not such as would bring out in a marked 
manner any action due wholly, or in great part, to heat. White polished ivory, such 
as M. Thore used for the rotating body, is a very bad absorber of heat rays; and it is 
quite possible that the aggregate of heat rays absorbable by polished ivory, emitted 
by a few square inches of lampblacked glass at 100°, 2 inches off, might not be inferior 
in amount to those emitted by the much larger surface of moist skin 8 inches off. It 
seemed possible to put this action to a test by blackening the ivory cylinder. If the 
action was, as M. Thore seemed to think, one inherent in the human organism, and 
not an effect of heat, the effect of blackening the cylinder should not materially alter 
the relative effects of the face and the hot-water flask; the action of the boiling water 
should still be less than that of the face. If, on the other hand, the action was one in 
which radiant heat played the principal part, the effect of blackening the ivory cylinder 
would be to upset this ratio, and to give a decided preponderance in favour of the hot- 
water flask. The ivory cylinder was accordingly blackened by holding it over the 
