12 DR. FARADAY’S EXPERIMENTAL RESEARCHES IN ELECTRICITY. (SERIES XIX.) 
action on the ray is the same, wherever the tube is placed, within the helix, in relation 
to the axis. The same result was obtained when a larger tube of water was looked 
through, whether the ray passed through the axis of the helix and tube, or near the 
side. 
2204. If bodies be introduced into the helix possessing, naturally, rotating force, 
then the rotating power given by the electric current is superinduced upon them, 
exactly as in the cases already described of magnetic action (2165. 2187-)- 
2205. A helix, twenty inches long and 0’3 of an inch in diameter, was made of un- 
covered copper wire, 0'05 of an inch in diameter, in close spirals. This was placed 
in a large tube of water, so that the fluid, both in the inside and at the outside of the 
helix, could be examined by the polarized ray. When the current was sent through 
the helix, the water within it received rotating power ; but no trace of such an action 
on the light was seen on the outside of the helix, even in the line most close to the 
uncovered wire. 
2206. The water was inclosed in brass and copper tubes, but this alteration caused 
not the slightest change in the effect. 
2207- The water in the brass tube was put into an iron tube, much longer than 
either the Woolwich helix or the brass tube, and quite one eighth of an inch thick in 
the side; yet when placed in the Woolwich helix (2192.), the water rotated the ray 
of light apparently as well as before. 
2208. An iron bar, one inch square and longer than the helix, was put into the 
helix, and the small water tube (2203.) upon it. The water exerted as much action 
on the light as before. 
2209. Three iron tubes, each twenty-seven inches long and one-eighth of an inch 
in thickness in the side, were selected of such diameters as to pass easily one into 
the other, and the whole into the Woolwich helix (2192.). The smaller one was sup- 
plied with glass ends and filled with water; and being placed in the axis of the 
Woolwich helix, had a certain amount of rotating power over the polarized ray. 
The second tube was then placed over this, so that there was now a thickness of iron 
equal to two-eighths of an inch between the water and the helix; the water had more 
power of rotation than before. On placing the third tube of iron over the two former, 
the power of the water fell, but was still very considerable. These results are com- 
plicated, being dependent on the new condition which the character of iron gives to 
its action on the forces. Up to a certain amount, by increasing the development of 
magnetic forces, the helix and core, as a whole , produce increased action on the 
water; but on the addition of more iron and the disposal of the forces through it, 
their action is removed in part from the water and the rotation is lessened. 
2210. Pieces of heavy glass (2151.), placed in iron tubes in the helices, produced 
similar effects. 
2211. The bodies which were submitted to the action of an electric current in a 
helix, in the manner already described, were as follows: — Heavy glass (2151. 21/6.), 
