122 Reply to Mr. Barnes on Magnetic Polarity. 



by the method which I employed. Besides, as the objec- 

 tions which I urged are to be found in every standard trea- 

 tise on magnetism, I did not expect any credit for their mere 

 repetition. 



Under these circumstances I was somewhat surprised that 

 Mr. Barnes, in the " Notice," published in your last num- 

 ber, should have pronounced with so much boldness in favor 

 of Mr. Eaton's proposed improvement. Above all I was 

 surprised that he should have attributed my remarks to im- 

 proper motives, when I venture to assert that no part of 

 them will warrant such an inference. 



After the positive declaration with which the ' notice 1 is 

 prefaced, I was prepared to find a detail of conclusive ar- 

 guments, or accurate experiments in its support. But 

 strange as it may appear, there is not a single fact or experi- 

 ment relating to the main question in dispute ; viz. — Wheth- 

 er tipping the ends of a compass needle with brass, does or 

 does not affect its directive force ? We have, it is true the 

 author's assertion, " that the fitful variation of the compass 

 is caused by the magnetism of the card," for which Mr. Ea- 

 ton has proposed a " simple and efficient remedy." Wheth- 

 er this assertion is a sufficient answer to my former remarks, 

 is not for me to determine. The proposed improvement 

 and the objections to it are now fully before the public, and 

 I shall cheerfully abide their decision. In the mean time, 

 however, I can hardly suppose that Mr. Patten will risk the 

 reputation which he has acquired as an artist, by sending 

 forth instruments, which to say the least, carry with them the 

 evidence of imperfection. 



I cannot omit the present opportunity, of making a few 

 observations upon the remaining part of Mr. Barnes' pa- 

 per ; and although he has so freely pronounced upon the mo- 

 tives which actuated me, I shall be content with inquiring 

 into the merits of the experiments and results which he has 

 offered. 



We are told by Mr. Barnes that " Mr. S. Dodge of the 

 western High School of Rochester, took the (iron ?*) win- 

 dow bar which lay near it," (the compass needle,) " and pla- 

 cing it perpendicularly found that the lower end was a north 

 pole. He inverted the bar, and was surprised to find the 

 same result, that is the poles were instantly changed by in- 



* This word and its annexed (?) were inserted by the editor. 



