12 Mr. Mull ins 07t MagJieto-electrical Mac/u?ies, 



adorn their museums, by proper application to its present 

 owner, W. Champ, a fisherman residing at Seaton. 



The sketches, 1 may observe, were taken with the camera 

 ucida, and are therefore, I trust, tolerably faithful. 

 With respect, I am, yours, &c. 



Sidmouth, Nov. 8, 1836. N. S. Heineken. 



II L 0?i a Mode of obtaining increased Power from Magneto^ 

 elecb'ic Machijies ; i?i Reply to the Rev. W. Ritchie, LL.D, 

 By Fred. W. Mullins, Esq., M.P., F.S.S.,M.R.L, ^c* 



I 



DID not receive the September and October Numbers of 

 the Lond. and Edinb. Philosophical Magazine, till the 

 commencement of the present month (November), and in con- 

 sequence was not previously aware that Dr. Ritchie had made 

 any observations in relation to my remarks on magneto-elec- 

 tric machines in page 120 of the August Number. I now hasten 

 to correct some misapprehensions which it appears that gen- 

 tleman has fallen into with respect to my statements in the 

 paper alluded to. 



Dr. Ritchie seems to think that I approve of bar magnets for 

 magneto-electric machines in preference to horseshoe ones : in 

 this respect he greatly mistakes me ; for I distinctly stated that it 

 was before trial I believed the former to be superior to the 

 latter; but that " ^^r trial" it appeared to me that the 

 power oiall such instruments was very imperfectly developed ; 

 which impression led to the inquiry and subsequent discovery 

 already mentioned : so far from dissenting from Dr. Ritchie's 

 opinion as to bar magnets, I fully concur with him in be- 

 lieving that of two bars of equal size tempered to the same 

 colour, and magnetized equally, one of which is divided into 

 two equal portions, and the other bent into the horseshoe 

 form, the latter will exhibit the greater power: so far we 

 agree ; but if Dr. Ritchie means to assert that the power of 

 the latter will exceed that of the former, after the addition of 

 the magnetized arcs, then he must permit me to say, that I 

 consider him to be decidedly in error, and feel myself, after 

 further experiments, fully justified in adhering to my former 

 opinion of the great superiority of bar magnets with magnetic 

 arcs for magneto-electric instruments, I quite agree with 

 Dr. Ritchie, that " facts are stubborn things to get rid of" 

 oubtedly they are much to be preferred to arguments 



ounded on the imperfectly developed principles of a science 



* Communicated by the Autlior. 



