232 Proceedings of Philosophical Societies. [March, 



1. By Mr. Scoresby's first process (which he denominates the 

 simple process, to distinguish it from the second, or compound 

 process), he obtained a maximum magnetical effect on a steel 

 wire of about six inches long, capable of lifting a nail of 186 grs. 

 which effect the compound process raised up to 326 grs. In 

 other cases, an equal and sometimes a superior effect was pro- 

 duced. 



2. In respect of temper or degree of hardness of the wires, it 

 was found that the softest wires obtained generally the highest 

 power, and were most easily magnetized, but the effect °soon 

 went off". 



3. By using a larger bar of iron (about eight feet in length), a 

 great increase of magnetical power was obtained, a wire of only 

 six inches long being made to lift, by hammering by the com- 

 pound process on this bar, a weight of 669 grains, or four times 

 the weight of the wire. 



4. The limit to the magnetism given to the wires, Mr. Scoresby 

 considers to be determined by the magnetism of the iron bars 

 employed. The bars being simply placed vertically, become 

 slightly magnetic by position from the earth. This polarity is 

 increased by hammering them while they remain in a perpendi- 

 cular position. An increase of magnetism continues to obtain 

 by repeated hammering the bars up to the extent that Mr. 

 Scoresby developed. But the maximum required the bars and 

 wires to be very often hammered, and the process to be conti- 

 nued at intervals for a few minutes at a time, during several 

 days. For a wire, however, to be made to lift its own weight 

 required only a few minutes hammering, and when the bars had 

 become magnetic by use, a single blow with a hammer was 

 sometimes found sufficient to enable the wire to lift its own 

 weight. To produce the best effect, it is important to have the y 

 steel wires polished at the end, and always to use the same end 

 downward, which obtains north polarity; for by this means, Mr. 

 S. found that an increase of capacity for magnetism in the wires 

 took place after almost any operation. 



Mr. S. conceives that the high effect obtained by percussion 

 depends on the disposition that percussion gives to the ferrugi- 

 nous particles, for assuming that condition to which we apply 

 the name magnetic. The particles of ferruginous substances, 

 especially steel, resist this condition to a certain extent, which 

 resistance percussion tends to overcome. The general law Mr. 

 S. resolves into this ; that percussion on magnetizable substances 

 in mutual contact inclines them to an equality of condition. And 

 this effect he illustrates, by the tendency of bodies unequally 

 heated, to assume, when placed together, the same temperature. 

 And from the tendency of the cooler bodies to acquire tempera- 

 ture, and the hotter to lose temperature, he explains the appa- 

 rently opposite proposition, that magnetism is both developed 

 and destroyed by percussion. The power of strong magnets J6 



