Mr. R. Phillips on the Magnetism of Steam. 509 



water, by bringing a copper pan filled with water under it, so 

 that the water might cover the lower portion of the coil ; the 

 upper portion of the coil was kept moist by having had some 

 loosely spun cotton twisted about it, the ends of which dipped 

 into the water. The gun-barrel was placed in the coil much 

 as before (:20.), and was supported without touching the coil ; 

 consequently any little alteration, produced by the heat of the 

 steam, in the position of the coil, could not move the iron; the 

 gun-barrel lay entirely under water. The steam was used at 

 35 to 40 lbs. on the inch, as at that pressure a difference of a 

 few pounds did not much affect the galvanoscope. A few puffs 

 of steam made the water about the coil to boil ; after which, 

 when the circumstances of the experiment appeared to be very 

 steady, I observed that one puff of steam could move the edge 

 of the needle across the field of view. The gun-barrel was 

 removed, and now two or three puffs of steam, acting through 

 each alternate vibration, could only produce a swing half 

 across the micrometer. A solid brass rod, •? inch diameter 

 and about 6 inches long, being now laid in the place of the 

 gun-barrel, produced no alteration in the swing of the mag- 

 netic needles ; the brass rod being removed, and the gun- 

 barrel replaced, the motion of the magnets at once became as 

 strong as before. It now follows that the action of the iron 

 on the galvanoscope is independent of any little change of tem- 

 perature it may produce. The swing was towards C when 

 the steam was turned on. 



27. In these experiments I did not perceive any difference 

 between the first and following puffs of steam ; and the swing 

 was, I think, at least as great at 40 lbs. as at any lower pres- 

 sure. 



28. The brass jet (9.) was screwed into the end of the coil 

 from which the steam escaped (26.), which apparatus in other 

 respects remained as before; this alteration caused an in- 

 creased pressure in the coil, and the condensation was con- 

 sequently very rapid ; so much so, that what escaped from the 

 brass jet looked more like water than steam. The swing, 

 when the gun-barrel was either in or out of the coil, remained 

 just as before (26.), the pressure in the boiler being about 

 40 lbs. on the inch. 



29. A pewter tube, 9 feet long and \ inch internal diameter, 

 was made into a dense cylindrical coil 4 inches long, the dia- 

 meter of the external surface of which was 2*5 inches, and the 

 diameter of the interior 1'25 inch. This coil was attached to 

 the boiler by means of a short brass connecting piece, the 

 steam-way of which was cylindrical, and /^ inch diameter ; 

 the coil was supported horizontally, and pointed about east 



