On the Constitution of the Electric Fluid. 33 



it is possible for any verbal statement to describe. It does not 

 appear that Mr. Swale ever actualhj ivrote out for the press those 

 portions of his geometrical sketches intended for Parts II. andlll., 

 of his " Geometrical Amusements," although the MSS. contain 

 much available matter, wliich, to him, would have required little 

 more than transcription and arrangement. The titles of the 

 manuscripts previously enumei'ated have no reference to their in- 

 tended destination, but are adopted as somewhat indicative of the 

 geometrical character of their contents ; he did not hesitate to 

 term those amusements which to others less gifted would be found 

 a severe mental exercise. Even were this not so, all farther 

 speculations in the way of pubhcation would have been effectually 

 stopped by the losses attendant upon the unsaleable character of 

 ''^Part I."; the reactionary taste for the Geometry of Coordinates 

 had already been created, and the Ancient Analysis, unable to cope 

 with this more powerful instrument of research, rapidly sunk into 

 disuse : the " Geometrical Amusements" were of too antiquated 

 a cast to secure many purchasers, nor did the " Apollonius" secure 

 a better fate : — the first number " did not pay," whilst the second 

 proved almost "a dead failure," partly from the above causes, 

 but principally, as Mr. Marrat informs me, from Mr. Swale^s 

 admitting into its pages a long and intemperate attack upon the 

 Newtonian System of Astronomy, by his friend Bartholomew 

 Prescot. 



Burnley, Lancashire. 

 Feb. 28th, 1852. 



V. On the supposed Identity of the Agent concerned in the 

 Phienomena of ordinary Electricity, Voltaic Electricity, Electro- 

 magnetism, Magneto-electricity, and Thermo-electricity. By 

 M. Donovan, Esq., M.R.I.A. 



[Continued from vol. iii. p. 457.] 

 Section VI. 



I NOW proceed to the consideration of another alleged proof of 

 this identity, found in the magnetic properties known to be 

 exercised by common and voltaic electricity. Notwithstanding 

 the difficulty of collecting the precise opinions of philosophers 

 concerning the mutual dependence on each other of magnetism 

 and electricity, loosely ex])ressed as they sometimes arc, it will 

 probably Ijc a safe enunciation to say, that by some, the two 

 powers arc supposed to be identical ; by others, that being each 

 mi generis they reproduce each other ; by others, that although 

 different they are always concurrent ; while others speak obscurely 

 aVjout "the current" and its power of producing magnetism, the 

 Phil. Mag. S. 4. Vol. 4. No. 22. July 1852. J) 



