84 Mr. Bennet's Experiments on a new 
EXPERIMENT IV. 
A bristle was suspended horizontally by a spider's thread 
somewhat stronger than the last, and after turning the wheel 
till it produced 4800 revolutions, it shortened the thread from 
three inches to one inch ; yet either end of the bristle would 
move towards any warm substance which was presented to it, 
either with or against the direction of the twist. 
EXPERIMENT V. 
Several other light substances were suspended by fine spi- 
der's threads, and placed in a cylindrical glass about two inches 
in diameter, as the thinnest part of the wing of a dragon-fly, 
thistle down, and the down of dandelion ; of these, the last 
appeared most sensible to the influence of heat, for when this 
down was fastened to one end of a fine gold wire suspended 
horizontally, or to one end of two bits of straw joined together 
in the form of the letter T inverted, it would turn towards any 
person who approached it at the distance of three feet, and 
would move so rapidly towards wires only heated by my hand, 
as very much to resemble magnetic attraction. See Tab. II. 
fig. 1. 
EXPERIMENT VI. 
A bottle filled with cold water was brought near the glass 
cylinder, standing in a warm room, and soon after the down of 
dandelion appeared to be repelled by the bottle, by turning 
away from it. The bottle was removed to the other side, and 
the dandelion again moved towards the opposite side. 
These attractions and repulsions, since they acted through 
