360 Dr. M'Intyre oti the Attempt to demonstrate 



for May, this announcement of the fact that I have succeeded 

 in obtaining an electric spark from a natural magnet. 



I only know of the reported success of Signor Nobili, the 

 active philosopher of Reggio, in the same experiment, from the 

 vague notice which has appeared, without any statement of its 

 source, in the public prints; nor has even there any clew been 

 given to the mode of his procedure. It is of course, however, 

 upon the recent discoveries of our distinguished countryman 

 Mr. Faraday, that any experiments on this important point 

 must rest. 



I beg you to consider this as a simple notification. In a very 

 short period a full account of the experiment will appear in 

 the Transactions of the Royal Society of Edinburgh, before 

 whom it was read on the 16th instant, and which I shall have 

 much pleasure in forwarding to you. 



The first spark I obtained was upon the 30th of March. 

 I had not the experiment, however, completely under my com- 

 mand until Friday the 13th instant. Since that period I have 

 shown it repeatedly to Sir John Leslie, Professor Hope, and 

 a number of other gentlemen, who have all expressed them- 

 selves completely satisfied with the experiment. 



I remain, Gentlemen, your obedient Servant, 



Greenhill, Edinburgh, April 18th, 1832. James D. ForbES. 



LII. Remarks on an Article in the Philosophical Magazine 

 and Annals for March *, in "which it is attempted to demon- 

 strate the Truth of M.r. Drummond's Rule for calcidatingthe 

 relative Importance of certain Boroughs. By Dr. M'In- 

 tyre, F.L.S. f 

 T^HE subject of the boroughs must be too generally known 

 -*- to need any introductory explanation here ; especially as 

 the article on which I offer these remarks commences with a 

 correct statement of the problem, and of Mr. Drummond's 

 rule for its solution. 



Against that rule, various objections have been strongly 

 urged, and different solutions confidently offered ; yet G. V.'s 

 " Analyticcd Investigation of a Formida^ 8)C." is the only at- 

 tempt that I have seen to prove its correctness. 



Having laid down certain principles, and enunciated the 

 problem mathematically (p. 220), the writer proceeds, with 

 the aid of the calcidus of variations, to search for a formula 

 that may enable us to solve this problem conformably with 

 his " third principle." 



• N.S. Vol. xi. No. 63. March 1832. 

 t Communicated by the Author. 



«H 



