“ NEW FORCE ” OF M. J. THORE. 
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obtained of attraction in air and stronger repulsion in high vacua, although, 
owing probably to the blackening of the cylinder and pillar, or to the diminished 
sensitiveness of the apparatus, I could detect no repulsion at intermediate pressures. 
Igniting the spiral, so as to make the brass tube E hot, produced attraction or repulsion 
according to the degree of exhaustion, but it produced no rotation. Rotation, however, 
could easily be obtained by placing a flask of boiling water in front of the bulb, close 
Fig. 5. 
to a point equidistant from E and D ; and applying a gas-flame to this part of the 
bulb produced a still stronger effect. Experiments were carried out with this 
apparatus, gradually raising the exhaustion to a very high point, and noting the 
repulsion by the spiral, and the rotation by externally applied heat. The two 
phenomena ran absolutely in parallel lines ; when there was attraction of D to E, I 
could also produce negative rotation of D ; when the exhaustion was such that the 
attraction was nil, the rotation was ml also ; when the attraction changed to repulsion, 
