Lifting Power of the Electro-Magnet. 



513 



then = 1098-16, it is easy to compute from Tables xii. and xvm. the values of 

 L corresponding to 3/. But we can also compute the a^s, which under similar 

 circumstances would give a force = M, and one = M' ; the sum of these must 

 produce an L", which must also be the resultant of those components, and 

 therefore should be identical with L. The result is given in — 



Table XXIV. 



Considering the complicated nature of the process, L — L" is so small that 

 we may safely infer that magnetic excitement does not interfere with the trans- 

 mission of induction. The three last columns are given to show the relation 

 between a resultant and its components. The first of them, headed L — 231, 

 shows the actual increase of force produced by the lesser component, which, 

 especially for the higher powers, is less than would be anticipated. The second 

 is the ratio of the sum of components to their resultant; and the third the ratio 

 of the larger component to it ; both showing that it decreases relatively as they 

 increase. Of course, either higher or lower on the scale, the actual value of 

 the ratio would recede considerably from these. 



4. Lastly, the investigation of these laws is impeded by the interruption of 

 inductive transmission, which arises from the discontinuity at A and B, when 

 the keeper rests on the magnet, as stated in (c). This eSect is shown by com- 

 paring the last two pairs in Table xxu. Supposing the helix placed at A, 

 No. Ill represents the force excited there; No. 113, that at C; No. 114, that 

 at D, which is the minimum ; and No. 112, that at B. Now the force at C may 

 be expected to be less than that at B, for it is the resultant of (9') and(23'-2j; 

 the other of (7') and (25'-2); for, as is shown by the column Z — 2iJ/, resultants 

 are nearer the larger of their components than the less. It is, however, found 



