266 Mr. W. Sturgeon's Eleclro-mugnclical Experiments. 

 a = 3 — X 



. . , r <2<ix{i-x) 



r = «(l +«) sin 9. / . ' , =~ '■ 



x ' J V cos» i + 1^6 » — 4 1 x) x -\- '2 i x s ■ 



and in this case we have an exact value of the refraction in 

 finite terms ; the formula being integrable. Now the hori- 

 zontal refraction at p. 148 of the Journal is included in the 

 expression we have just found. Again, my general equation 



m + t 

 between the pressure y and the density z, is y = z m ; and 



when m = 2, y = z* which is the particular case in the Journal; 



and when wi = 4, y=~* which is the case I have chosen as 

 best representing the state of the atmosphere. Yet it seems 

 to be insinuated in the Journal that something is found out 

 different from my theory, and about as good. Now this is 

 nothing else than taking away from a person the result of his 

 own labour, and turning it against himself; which is no fair 

 way of dealing. 



I have now, by such arguments as hastily occurred, endea- 

 voured to vindicate my table from the burlesque comparison 

 in the Journal of Science. I am far from thinking that the 

 table is the only part of my paper by which science may, in 

 some degree, be benefited. But if it was necessary at this 

 time to discuss the particular results published for illustrating 

 the theory I had to propose, the objections ought, in the dis- 

 charge of a gratuitous office, to have been well-founded ; and 

 they ought to have been urged in a candid, open, and manly 

 manner. My purpose being merely to defend myself, I have 

 abstained as much as possible from all remarks on the table 

 in N. A. The construction of that table may hereafter be- 

 come a fair subject of discussion. But it is not impossible 

 that it may be withdrawn, and another of a less mysterious 

 construction substituted in its place ; as it appears that a 

 new method for the refractions was read before the Royal 

 Society at their meeting on the 5th February last. 

 I remain, gentlemen, &c. 

 April 9, 1824. James Ivory. 



XLIV. Electro- and Thermo-magnetical Experiments. By 

 Mr. William Sturgeon. 



To the Editors of the P/iilosopkical Magazine and Journal. 

 Gentlemen, 

 LTHOUGH the experiments I have detailed in my for- 

 mer paper have sufficiently satisfied myself with respect 



to 



A 



