TO THE MOVEMENT OF MACHINES. 7 



confess that isolated experiments will not lead to the object 

 in view. For this purpose, well followed up experiments, di- 

 rected by the knowledge, zeal, and the means at the control of 

 a scientific body, are necessary. I do not believe that Europe 

 can offer elsewhere a union of circumstances so favourable for 

 grand scientific enterprises as is presented by the illustrious 

 Imperial Academy. I submit my desire to advance experiments 

 in magneto-electricity to this distinguished body, whose en- 

 deavours are directed to the enlargements of the hmits of 

 each branch of science in which it engages, and to extend its 

 boundaries. 



We have no right to suppose that the limits of the magnetic 

 power which soft iron is capable of acquiring, are narrowly re- 

 stricted, or that they have ever been attained by experimentaUsts. 

 I have made on this subject an experiment which is not without 

 interest. The ends of the helix surrounding the horse-shoe I have 

 described (Art. 9), were placed in contact with a battery of 16 

 pairs of 72 square inches, recently constructed, and charged with 

 nitro-sulphuric acid (27). The armature, which weighed 3 lb., 

 was placed horizontally, and at a distance of 5 inches below the 

 extremities of the horse-shoe. As soon as the circuit was com- 

 pleted, this armature raised itself and sprung with such violence 

 towards the ends of the magnet, that we might, without exagge- 

 ration, estimate the force as equal to that acquired by fsiUing 15 

 to 20 feet. The result of a second experiment was somewhat less, 

 and after repeated experiments it was necessary to diminish the 

 distance to within two to thi'ee inches, to cause the armature to 

 spring towards the magnet with so powerful an energy. This 

 beautiful experiment deserves being repeated, but for its success a 

 fresh and powerful battery is necessary. For the present, we must 

 be content to measure in one way or another the mechanical force 



of the magnetism, or the useful work I / M ds = — — \ at our 



disposal, in the case of the attraction of the armature. The 

 mode of operation of this force renders it very difiicult to find an 

 exact measux-e to express the effects, due for the most part to 

 the active power produced by an accelerating force, the law' of 

 which is not exactly known. 



With respect to the state of magnetic saturation, we shall 

 never attain it, unless by augmenting at the same time the in- 

 tensity and number of the currents, to the influence of which the 



