Miscellaneous. 



SOS 



ed. I will, however, particularly notice the satisfactory results of the 

 experiments made last year with a boat of twenty-eight feet in length 

 and seven and a half feet in width, drawing 2| feet of water, and carry- 

 ing fourteen individuals, which was propelled upon the Neva at the 

 rate of about three English miles in the hour. The machine, which 

 occupied very little space, was set in motion by a battery of sixty-four 

 pairs of platina plates, each having thirty-six square inches of surface, 

 and charged, according, to the plan of Mr. Grove, with nitric and diluted 

 sulphuric acid. Although these results may perhaps not satisfy the 

 exaggerated expectations of some persons, it is to be remembered, that 

 in the first year, namely, in 1838, this boat being put in motion by the 

 same machine, and employing 320 pairs of plates, each of thirty-six 

 square inches, and charged with sulphate of copper, only half this velo- 

 city was obtained. This enormous battery occupied considerable space, 

 and the manipulation and the management of it was very troublesome. 

 The judicious changes made in the distribution of the rods, in the con- 

 struction of the commutator, and lastly, in the principles of the vol- 

 taic battery, have led to the successful result of the following year, ] 839. 

 We have gone thus on the Neva more than once, and during the whole 

 day, partly with and partly against the stream, with a party of twelve 

 or fourteen persons, and with a velocity not much less than that of the 

 first invented steam-boat. I believe that more cannot be expected from 

 a mechanical force, whose existence has only been known since 1834, 

 when I made the first experiment at Konigsberg, in Prussia, and only 

 succeeded in lifting a weight of about twenty ounces, by even this 

 electro-magnetic power. 



" I must, on the present occasion, confess frankly and without reserve, 

 that hitherto the construction of electro-magnetic machines has been 

 regulated in a great measure by mere trials ; that even the machines con- 

 structed according to the indisputable laws established with regard to 

 the statical effects of electro-magnets, have been found inefficient, as soon 

 as we came to deal with motion. Being always accustomed to proceed 

 in a legitimate manner, and feeling great regret at the irregular at- 

 tempts which were being made every-where, without any scientific 

 foundation, this state of things appeared to me so unsatisfactory, that I 

 could not but direct all my efforts to ascertain clearly the laws of these 

 remarkable machines. I submit the formulae relative to these laws, 

 which appear to me to recommend themselves as much by their simpli- 

 city as by the natural manner in which they develope themselves. Let 

 R. represent all the mechanical resistances acting upon the machine, 

 and v, the uniform velocity with which it moves : we have for the 



