Reviews, and Notices respecting New Booh. 363 



results and laws of this branch of science, up to the time of its publication, 

 in a well arranged form. At p. 173, the author, when describing this ex- 

 periment, says, " The mobile circle turns to take a position of equilibrium 

 as a conductor would do in which the current moved in the same direction 

 as in the spiral ; and in the same paragraph he adds, " It is therefore 

 proved that a current of electricity tends to put the electricity of conductors, 

 near which it passes, in motion in the same direction" These are the words 

 I quoted in my paper (78.). 



Le Lycee of 1st of January 1832, No. 36, in an article written after the 

 receipt of my first unfortunate letter to M. Hachette, and before my papers 

 were printed, reasons upon the direction of the induced currents, and says, 

 that there ought to be " an elementary current produced in the same di- 

 rection as the corresponding portion of the producing current." A little 

 further on it says, " therefore we ought to obtain currents, moving in the 

 same direction, produced upon a metallic wire, either by a magnet or a 

 current. M. Ampere was so thoroughly persuaded that such ought to be the 

 direction of the currents by influence, that he neglected to assure himself of 

 it in his experiment at Geneva.'* 



It was the precise statements in Demonferrand's Manuel, agreeing as they 

 did with the expression in M. de la Rive's paper, (which, however, I now 

 understand as only meaning that when the inducing current was changed, 

 the motion of the mobile circle changed also,) and not in discordance with 

 anything expressed by M. Ampere himself where he speaks of the experi- 

 ment, which made me conclude, when I wrote the paper, that what I wrote 

 was really his avowed opinion: and when the Number of the Lycee re- 

 ferred to appeared, which was before my paper was printed, it could ex- 

 cite no suspicion that I was in error. 



Hence the mistake into which I unwittingly fell. I am proud to correct 

 it, and do full justice to the acuteness and accuracy which, as far as I can 

 understand the subjects, M. Ampere carries into all the branches of philo- 

 sophy which he investigates. 



Finally, my note to (79.) says that the Lyc'e, No. 36, " mistakes the 

 erroneous results of MM. Fresnel and Ampere for true ones,'' &c. &c. In 

 calling M. Ampere's results erroneous, I spoke of the results described in, 

 and referred to by the Lycee itself; but now that the expression of the di- 

 rection of the induced current is to be separated, the term erroneous 

 ought no longer to be attached to them. 



April 29, 1833. M. F. 



LX. Reviews, and Notices respecting New Booh. 



Elements of Plane and Spherical Trigonometry, with its Applications 

 to the Principles of Navigation and Nautical Astronomy ; by J. 

 R. Young * : to which are added some original Researches in Sphe- 

 rical Geometry, byT.S.DAviEs, Esq.F.R.S.L.&E., F.R.A.S.,&c. 

 OUR old-fashioned elementary works on mathematical science, 

 though less erudite in appearance than their modern substi- 

 tutes, were characterized by some excellences which we rarely find 

 in recent treatises on the same class of subjects. One of these ex- 

 cellences was, the close connexion that was constantly kept in view 



* We were gratified to learn, since this review was written, that this 

 distinguished mathematician has been elected Professor of Mathematics in 

 the Royal Belfast Institution. 



3 A2 



