368 Mr Barlow’s Electro-Magnetic Experiments . 
We trust, however, that the rapid view of the Journal contained 
in the preceding pages, will convey to our readers an adequate 
idea of its nature ; and as we have made Capt. Scoresby describe 
the natural phenomena he witnessed, and state the speculations 
they gave rise to, and the difficulties and dangers he expe- 
rienced, in his own words , we feel confident, that we do him per- 
fect justice, and afford much more satisfactory and useful infor- 
mation to the public, than if we adopted the practice of throw- 
ing the author into the shade, by intruding our views and fan- 
cies in place of his facts and reasonings. 
Art. XVI. — Account of a Series of Electro-Magnetic Experi- 
ments , with Observations on the Mathematical Laws of Elec- 
tro-Magnetism. By Peter Barlow, Esq., Royal Military 
Academy, W ool wich . 
In several of the preceding numbers of this Journal*, we 
have endeavoured to make our readers acquainted with the very 
interesting electro-magnetic investigations and experiments of 
Oersted, Ampere, Sir Humphry Davy, Professors Moll and 
Van Rees, Mr Faraday, and Mr Barlow. 
The appearance of a second edition of Mr Barlow’s very in- 
teresting Essay on Magnetic attractions, and on the Laws of 
Terrestrial and Electro-Magnetism, enables us to resume this 
important and curious subject, and to lay before our readers a 
series of the most popular and instructive experiments in this 
new science. 
We were enabled, in a former number, Vol. VII. p. 281. to 
communicate an early account of Mr Barlow’s general law, and 
of the Formula f which contained it ; but as we gave only a 
brief notice of the apparatus which he added to Dr Hare’s colo- 
rimotor, we shall now supply this defect. 
* See this Journal , Vol. IV., p. 167, 406, 435; Vol. V. p. 301, 352, 301, 
392 ; Vol. VI. p. 83, 179, 220 ; Vol. VII. p. 281. 
+ This Formula was misprinted, it should have been Tan = — -■ ;° S , ^ . — 
1 1 cot A 4- sin f 
