Mr. R. Phillips on the Magnetism of Steam. 507 



moving towards C when the steam was turned on. The in- 

 tensity of the swing-producing force was, 1 think, at its maxi- 

 mum at 10-15 lbs. per inch; as the pressure rose, the swing 

 was obtained with more difficulty, and at 40 lbs. on the inch 

 no certain swing could be produced. On repeating this ex- 

 periment at a subsequent period with steam at 40 lbs. on the 

 mch, a feeble swing was obtained ; but in this latter case the 

 coil, instead of being bright, had become covered with a de- 

 posit of carbonate of lime. 



18. The galvanoscope was lowered until the upper needle 

 was in the same horizontal plane as the undermost side of the 

 upper portion of the coil, and the lower needle was in a hori- 

 zontal plane which came to about ^ inch below the lower sur- 

 face of the lower half of the coil. When the steam was turned 

 on, the needle made a start towards A ; and by shutting off 

 the steam during the next vibration, and repeating these ope- 

 rations two or three times, a considerable swing was obtained ; 

 but on attempting to increase this swing by continuing these 

 intermittent operations, the swing rapidly diminished. The 

 order in which the jet of steam and its cessation took place 

 was now inverted, which soon produced a very powerful swing, 

 the needle moving towards C when the steam was turned on. 

 The steam was used at from 30 to 40 lbs. on the inch. These 

 rather irregular motions (17, 18.) are probably connected with 

 those of the Armstrong's jet (13.). 



19. The coil was moved through an angle of 180°, the 

 angular motion being performed parallel to a plane forming a 

 right angle to the path of the steam, and the galvanoscope 

 was adjusted so that the interior surface of the coil might act 

 on the lower needle; by this arrangement the direction of the 

 steam as regards the needle was reversed. Many different 

 pressures were observed from a pound or two on the inch 

 to 40 lbs. As soon as any distinct swing was produced, it 

 was occasioned by the needle moving towards A when the 

 steam was turned on; as the pressure rose, this swing in- 

 creased until the steam was, I think, about 25 lbs. on the 

 inch, after which the increased pressure only occasioned a 

 somewhat diminished swing. 



20. The apparatus (19.) was now rather differently disposed, 

 the shield and galvanoscope were moved horizontally about 

 f inch, the direction of the motion being perpendicular to the 

 path of the steam ; also a piece of ani ron gun-barrel 7 inches 

 long and open at both ends, was fixed to a support, so that 

 the gun-barrel might easily be thrust into, or removed from, 

 the coil without bearing upon it; the axis of the gun-barrel 

 when placed in the coil formed a right angle to the path of 

 the steam, and was horizontal, and its direction lay not far 



