Action of Magnets on Bismuth and other Metals. 459 



certain and wavering. If the angle with the radial line were 

 less than that above, the bar would move into parallelism 

 with the radius.and go inwards: if the angle were greater, the 

 bar would move until perpendicular to the radial line and go 

 outwards. If the centre of the bar were still further out than 

 in the last case, or down by the side of the core, the bar would 

 always place itself perpendicular to the radius and go outwards. 

 All these complications of motion are easily resolved into their 

 simple elementary origin, if reference be had to the character 

 of the circular angle bounding the end of the core; to the di- 

 rection of the magnetic lines of force issuing from it and the 

 other parts of the pole; to the position of the different parts 

 of the bar in these lines; and the ruling principle that each 

 particle tends to go by the nearest course from strong to 

 weaker points of magnetic force. 



2301. The bismuth points well, and is well repelled (2296.) 

 when immersed in water, alcohol, aether, oil, mercury, &c, 

 and also when inclosed within vessels of earth, glass, copper, 

 lead, &c. (2272.), or when screens of 0*75 or I inch in thick- 

 ness of bismuth, copper or lead intervene. Even when a 

 bismuth cube (2266.) was placed in an iron vessel 2| inches 

 in diameter and 017 of an inch in thickness, it was well and 

 freely repelled by the magnetic pole. 



2302. Whether the bismuth be in one piece or in very fine 

 powder, appears to make no difference in the character or in 

 the degree of its magnetic property (2283.). 



2303. I made many experiments with masses and bars of 

 bismuth suspended, or otherwise circumstanced, to ascertain 

 whether two pieces had any mutual action on each other, either 

 of attraction or repulsion, whilst jointly under the influence of 

 the magnetic forces, but I could not find any indication of 

 such mutual action: they appeared to be perfectly indifferent 

 one to another, each tending only to go from stronger to 

 weaker points of magnetic power. 



2304. Bismuth, in very fine powder, was sprinkled upon 

 paper, laid over the horizontal circular termination of the ver- 

 tical pole (2246.). If the paper were tapped, the magnet not 

 being excited, nothing particular occurred; but if the mag- 

 netic power were on, then the powder retreated in both di- 

 rections, inwards and outwards, from a circular line just over 

 the edge of the core, leaving the circle clear, and at the same 

 time showing the tendency of the particles of bismuth in all 

 directions from that line (2299.). 



2305. When the pole was terminated by a cone (2246.) 

 and the magnet not in action, paper with bismuth powder 

 sprinkled over it being drawn over the point of the cone, gave 



2 I 2 



