Mr. R. Phillips o?i the Magnetism of Steam. 505 



steam might act principally on the lower side of the undermost 

 needle, instead ot acting equally on both as before, everything 

 else being as in the former experiment. When the steam was 

 turned on, the needle began to move towards A ; and by 

 alternately shutting oft' the steam and letting it issue at the cor- 

 responding positions of the needle, a vibration through full 

 half of the micrometer was obtained; and then by making the 

 blasts of steam synchronical with the opposite vibrations of 

 the needle, the motion was checked. 



11. The glass tube was now taken away, the galvanoscope 

 lowered as in (9.), and the shield and galvanoscope moved 

 horizontally about f inch in a perpendicular direction to the 

 path of the steam, which was used at about 35 pounds on the 

 inch. Operating as before, I could with this jet of steam 

 more easily obtain the swing, the motion being towards C 

 when the steam was turned on. Water being placed in the 

 Armstrong's condenser, produced no alteration in the magnetic 

 effects of the jet of steam. 



12. The effect of this jet (11.) was much greater than that 

 of the current of electricity of an Armstrong's jet under the 

 most favourable circumstances. The comparison was made 

 in the following manner: — 1 found that an Armstrong's jet 

 could discharge more steam in a given time than the brass 

 jet (11.), also that the electricity produced by the Armstrong's 

 jet could deflect the needle of a galvanometer of the ordinary 

 construction 3 or 4 degrees. I then found that a small voltaic 

 arrangement capable of deflecting the needles of the galvano- 

 meter 4°, and having a conducting wire lying in the path of 

 the steam, acted far less on the needles of the galvanoscope 

 than the blast of steam from the brass jet (11.). Also when 

 an Armstrong's jet was substituted for the brass jet, and water 

 placed in the condenser, I could perceive no difference in the 

 swing, whether the steam passed by the galvanoscope in a 

 highly electrified condition, or whether the electricity was, in 

 a great measure, collected by means of a number of fine points 

 almost as soon as it left the wooden channel. The points 

 were supplied by two small concentric loops of wire-gauze, 

 placed edgeways in the steam at a distance in different expe- 

 riments of from ^ to ^ inch from the end of the Armstrong's 

 jet. The galvanoscope was as before (11.), except that it was 

 placed about | inch further from the jet, but at about the 

 same distance from the path of the steam. 



13. There is a singular variation which I have sometimes 

 observed in the magnetic effect produced by the steam issuing 

 from an Armstrong's jet; namely, that the action of the steam 

 on the galvanoscope is much stronger when one of the needles 



