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



145. A glass tube 28 inches long was formed into a coil of 

 five convolutions. This glass tube happened to be rather 

 conical ; its internal diameter at one end being ¥ 7 q inch, and 

 at the other end about ¥ 6 ^ inch, and the tube was ¥ 9 ^ inch ex- 

 ternal diameter. The end of the tube having the larger dia- 

 meter was united to the condenser, and the iron was placed 

 in the coil ; the steam circulated in a direction contrary to 

 that of the hands of the watch. In these experiments, 10 lbs. 

 on the inch was found to be an advantageous pressure for the 

 steam. On opening the cock of the boiler the needle moved 

 towards C; the steam being then shut off, the needle made a 

 sudden start towards A ; and I think the force which sent the 

 needle towards A was greater than that which moved it to C. 

 Three puffs of steam sent the needle nearly across the field 

 of view. 



146. The iron was now removed, the swing remained much 

 as before ; if there was any difference, I think it was rather . 

 greater without the iron. After many experiments I thought 

 I could perceive that the needle, when the iron was in, did 

 not so promptly obey the steam as when the iron was out, but 

 seemed to move rather sluggishly, as if the iron resisted the 

 production of the magnetic force of the coil. 



147. The end of the tube having the smaller diameter was 

 now united to the condenser by the same piece of brass which 

 was used in the preceding experiment, and the steam circulated 

 in the same direction. The swing, when the steam was turned 

 on, was to C, but much more feeble than before, and the coil 

 worked better at a higher pressure. I could not perceive that 

 the iron varied the magnetic energy of the coil. 



148. It immediately follows from the foregoing experiments 

 (132, 135, &c), that the direction of the magnetism imparted 

 to a coil is not directly, if indeed it is at all, connected with 

 the direction of the motion of the steam. In these experi- 

 ments two magnetic forces are observable, always opposite in 

 direction and about equal in power : one of these 1 have be- 

 fore shown to be intimately connected with condensation, the 

 other is produced under circumstances where condensation 

 cannot take place, but where evaporation does. The experi- 

 ments (136, 137.) show very conclusively that the friction of 

 steam along a pipe, apart from condensation or evaporation, 

 produces no magnetic effect. A more complete consideration 

 of all these experiments must be deferred until I have finished 

 a further set. 



7 Prospect Place, Ball's Pond Road, 

 July 27, 1850. 



