58 



Dr. Ritchie's Bephj to Mr. llaiiiey's 



firm basis, tliat I again trouble you with the following re- 

 marks. 



Ist. Mr. IJainey's first false position is, that " there is no 

 known limit at which soft iron ceases to allow of further in- 

 duction by an increase of the inducing power," and he also 

 takes for granted, that a magnet having doiible the power will 

 induce on the same armature twice the effect. The following 

 experiments must convince every person that the lifter or ar- 

 mature has a limit to its capability of receiving magnetism, and 

 that its capability of receiving new increments diminishes ra- 

 pidly as the inducing power increases. 



Roll a covered wire about 

 the half of an electro-magnet 

 from A to B. Do the same 

 with an equal wire from C to 

 D. Connect the first helix 

 with an elementary battery, 

 and ascertain the lifting 

 power of the magnet. Con- 

 nect the other helix with an 

 equal battery, and instead of 

 the lifting power being dou- 

 bled, acccording to the principle assumed by Mr. Rainey, its 

 power may not be increased a third or fourth, or even a tenth, 

 if the battery be a powerful one. 



2nd. The second false principle which Mr. Rainey assumes 

 is, that the lifter, by its reaction, can induce a higher state of 

 magnetism in the inducing magnet than what it naturally pos- 

 sesses. The experiment from which he deduces this novel 

 principle by no means warrants the conclusion. The experi- 

 ment every person who knows anything of the subject, knows 

 to be correct; the reasoning by which the conclusion is de- 

 duced must be as easily seen to be fallacious. The experiment 

 is, that a soft steel electro- magnet receives more powerful j>^r- 

 manent magnetism when a piece of soft iron is across its poles 

 than it does when the poles are not united. Mr. R. concludes 

 that " as the induction from the galvanic current was the same 

 in each stage of this experiment, the increase of permanent 

 magnetism would appear to depend upon the reaction of the 

 keeper, which, by the converse of Dr. Ritchie's reasoning, must 

 then possess a higher state of magnetism than the magnet to 

 which it is applied." Here again Mr. Rainey takes for granted 

 that the induction from the galvanic current is the same in the 

 steel magnet, whether it form a closed circuit, as it does when 

 its poles are connected by soft iron, or an interrupted circuit, 

 when the poles are not connected. Now every person who 



