IBS ATTRACTION. 



2. MAGNETISM. 



(a.) This is a power usually manifested in iron or steel, after hav- 

 ing received particular treatment, or after having been for some time in 

 a particular position. 



(b.) It belongs also to nickel, and to cobalt, which like nickel, 

 is found to be the more magnetic, the purer it is made. 



(c.) Magnetism resides also in the earth. The magnetic poles are 

 not coincident with the poles of revolution. In the Arctic region, 

 the magnetic pole is* in 69 16' of N. lat. and 98 8' W. lon.f 

 d.) Repulsion as wdl as attraction is predicable of magnetism, 

 e.) Similar magnetic poles repel, and opposite poles attract. 



f.) Magnetism is connected, in some mysterious manner, with the 

 other imponderable powers, light, heat, and electricity. 



Sg.) The solar rays, especially the violet, magnetize a needle.^ 

 h.) The calorimotor evolves heat with great energy, but its elec- 

 tricity is of a very low intensity ; still, it magnetizes needles power- 

 fully, when there is no light perceptible. 



(i.) Similar effects, in a greater or less degree, are produced by 

 all the varieties of galvanic apparatus ; all the known imponderable 

 fluids being occasionally present together. 



0/0 ^ e cannot say, therefore, whether magnetism is a distinct 

 power, or a property or appendage of one or more, or of all the other 

 imponderable powers. The magnetic power, both in its attractions 

 and repulsions, is pleasingly exhibited by magnetic needles, fish, boats, 

 and balls, by the horse shoe magnet, bar magnet, &c. Many articles 

 of iron and steel become magnets spontaneously, especially such as 

 have stood long vertically or nearly so, and more especially, if in the 

 magnetic meridian. Magnetism is excited also by rapid rotary mo- 

 tion. 



3. GALVANISM 



1. Requires, and will receive a distinct statement near the end 

 of this work, but as this remarkable power actually arranges in a 

 natural method, all the elements and compound principles of matter, 

 it is mentioned here among the general powers. 



(a.) Mode of excitement. Nearly as various as matter, almost all 

 substances of different natures, or sometimes the same substance in 

 different conditions, arranged in a particular connexion, will serve to 



* Or was at the lime of Captain Parry's late voyages ; I Icnow cot whether any 

 observations have since been made, to ascertain its constancy in latitude ; the varia- 

 tions of the needle E. and W., eecm to prove that the magnetic pole varies in longi- 

 tude, t Am. Jour. Vol. XVI, p. 149. 



t Morrichini's and Mrs. Somerville^s experiments on magnetizing needles, arc 

 said to have failed in skilful hands ; it is suggested that the needles might have been 

 magnetized before. The editor of the Pbi]os. Magazine, new series, Vol. IV, p 

 221, thinks that, at least, the magnetism was increased. 



