290 Researches in the Theory and Calculus of Operations. 



of the atoms in the straight line of the movement; but as 

 such revolving transmission of force exists, during the in- 

 terval of time occupied by the scraper in passing from one 

 circle of atoms to the next, the revolutive force in the circle 

 reached has advanced one atomic step in its round, and 

 thus is the spiral direction given. 



It may well be that spherical and cylindrical emanating 

 forces, originally imprinted on all the elementary substances 

 and arranged as above sketched, shall seldom give rise to 

 sensible magnetic effects, and that these may be improved 

 or altered by introducing strong pressure, etc., to change 

 the direction of the greatest density of the atoms of the 

 substance descending from perfect paramagnetism in row, 

 or through the centre of indifference, down to perfect dia- 

 magnetism in bismuth (Tyndall). 



In the contrast between soft iron and steel respecting 

 magnetic behaviour, the former acts aa a free conductor of 

 magnetic force, its anode being formed by the constantly 

 emanating magnetic force of the earth, and the cathode by 

 the point of connexion with the instrument in presence, the 

 entire piece composing one complete wave of tension with 

 venter at the center, which retires as soon as the connexion 

 is severed. It is the analogue of the conducting wire of the 

 galvanic electricity, with this agreement and difference : 

 The perfect electric conductor, whatever be its length, con- 

 stitutes one single whole wave of tensional force, not con- 

 ceived as divided into molecular or atomical wavelets, and 

 its dynamical movement is linear; while in the soft iron, 

 the magnetical movement is circulo-spiral or helicoidal. 

 Different in constitution from this is the case of steel and 

 other substances possessing magnetic power or capacity. 

 Such substances are either compound or compressed. A 

 compound atom is a case of equilibrium between a positive 

 and a negative hemisphere of force. By the process of con- 

 verting iron into steel, the carbon unites with the iron and 



