Mr. R. Phillips on the Magnetism of Pewter Coils. 233 



a steam-way 2% inch diameter ; these stop-cocks are denoted re- 

 spectively by N and 0. There was also a thick wad of loosely 

 spun cotton, which could either be wrapped about the coil or 

 stuffed into it. In these experiments it was found necessary to 

 interpose a sheet of lead-foil between the zinc screen and the 

 coil ; otherwise the steam produced from the wad, striking on 

 the shield, considerably interfered with the purity of the result. 



159. The wad was placed on the outside of the coil and 

 thoroughly drenched with water. N was now united by a brass 

 connecting piece to the cock of the boiler ; was partly and 

 sometimes fully opened and N shut. On opening N the swing 

 was to C ; five pufi*s gave a swing about three-quarters the length 

 of the scale. In these experiments the cock of the boiler is 

 always to be understood as open. 



160. N was partly opened; on alternately opening and shut- 

 ting 0, the swing was to A when was opened, and to C when 

 O was shut. When N was fully opened, the swing was much 

 less. 



161. The wad was now removed from the outside and thrust 

 inside the coil and saturated with water. O being partly open, 

 on fully opening N the swing was to A, and rather less than the 

 swing to C when the wad was outside. 



162. The stop-cocks N and O were used as described in (160.). 

 When was shut the needle moved to A, and to C when was 

 opened. In experiments where either N or O was partly opened, 

 the area of the steam-way was probably about equal to a circle 

 y2 inch diameter. 



163. Many other experiments were made with this coil, which 

 it is not considered necessary to mention, as they only showed, 

 in addition to what I have just narrated, that which is abun- 

 dantly proved by former experiments ; namely, that the two ends 

 of the axis of the coil are in opposite magnetic states, and that 

 the direction of the magnetism is independent of the direction of 

 the motion of the steam. 



164. One end of the pipe of the coil (29.) was united to the 

 cock of the boiler, and there was a distance of ten inches of 

 pewter pipe between the coil and the connecting pieces; the 

 other end of the pipe of the coil held the brass jet (9.). The 

 axis of the coil was placed perpendicular to the horizon. The 

 needle of the galvanoscope lay in a horizontal plane about '4 

 inch lower than a horizontal plane resting upon the upper end 

 of the axis of the coil. When the steam passed, the swing was 

 to A, and one puff sent the needle nearly the length of the scale. 

 The apparatus was now adjusted so that the needle stood '6 inch 

 lower with regard to the coil ; the swing was still to A, and 

 nearly as strong as before. The needle was now placed about 

 equidistant from either end of the coil ; the swing was still to A, 



