Mr. Rainey's Analysis 9/ Dr. Ritchie's Hephj. 193 



series of papers preparing for the Royal Society. That they 

 involve a principle in physiology at once extensive and novel, 

 will not, I think, be now denied. 



1 may add that in some of the Invertehrata, the necessity for 

 the nerves being intervertebral not existing, the excito-motory 

 system of nerves, with their axis, may be as distinct in their 

 anatomy as they are in their functions. This question I am 

 about to subject to the test of experiment. 



14, Manchester Square, 

 November 25, 1836. 



XLIII. An Analysis of Dr. Ritchie's Paper, in reply to Mr. 

 Rainey's last Commiinicatio7i concerning Magnetic Reaction, 

 contained in the Philosophical Magazin^ for January, By 

 G. Rainey, M.KC.S.'" 



T^HAT Dr. Ritchie is in error will be clear from the fol- 

 -■- lowing facts. The expression most frequently employed 

 to explain the action of a magnet upon its keeper is, that the 

 magnet induces on the contiguous ends of the armature op- 

 posite states of magnetism, and that in consequence of this 

 dissimilarity these oppositely magnetized extremities attract 

 one another, evidently inferring that attraction follows as a 

 consequence of induction. If a piece of soft iron be applied 

 to magnets of different magnetic intensities, the adhesion would 

 most undoubtedly be the greatest between the soft iron and 

 the strongest magnet; and if any other magnet still stronger 

 were applied to the same keeper, this increase would be mani- 

 fested by a still more forcible attraction of this keeper by the 

 magnet; and so on, without any known limit : consequently, as 

 attraction is the effect of induction, the induction may be in- 

 ferred to have no known limit, and the position to be true. 



Dr. Ritchie says, " he, Mr. Rainey, also takes for granted, 

 that a magnet having double the power will induce in the same 

 armature twice the effect." I am not conscious of ever having 

 made such an assertion. 



Dr. Ritchie, to refute my first position and the one incor- 

 rectly attributed to me, has invented the following experiment: 

 '* Roll a covered wire about the half of an electro-magnet 

 A 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. Connect the other helix with an 

 equal battery, and instead of the lifting power being doubled, 

 according to the principle assumed by Mr. Rainey, its power 



• Communicated by the Author. 

 Third Series, Vol. 10. No. GO. March 1837. 2 C 



