336 Method of Making Permanent Artificial Magnets. 



Positive Pole. Negative Pole. 



spective coils. The coils were varnished in order that they might 

 be immersed in water, without any interruption taking place in 

 the current of the galvanic fluid. The two extremities of the 

 wire were attached to a battery, consisting of a single pair of 

 plates, each plate of about twelve square inches. A horse-shoe of 

 soft iron was then introduced into the coils to test their magnetic 

 power ; the iron was found capable of sustaining about one and 

 a half pounds. After withdrawing the iron, a piece of steel, of 

 the same shape, made red hot, was introduced and both steel and 

 wire were plunged into cold water, and contrary to my expecta- 

 tion the steel was found to be but feebly magnetic. I then re- 

 peated the experiment, with this difference, that before cooling 

 the steel, I united its two extremities (projecting below the ends 

 of the coils) by a piece of soft iron, which by keeping up the 

 circulation of the magnetic fluid, enabled me to procure a magnet 

 of some power, that is to say, the steel used weighing one ounce, 

 after undergoing this process, was able to sustain six ounces. It 

 must be recollected that the instruments used were of a rude 

 character, and that they could not create a temporary magnet, of 

 more than one and a half pounds power. By this experiment it 

 will be seen that one fourth the maximum power developed was 

 secured permanently, but it is not to be supposed that in all in- 

 stances the ratio of the power secured, to the power developed 

 will be as great as in this, but I believe if proper proportions be 

 observed in the steel used, there will be an approximation to this 

 ratio, even when the magnetic force is of great intensity. 



This method of making magnets may be of some practical 

 utility, for the apparatus required is of the simplest kind, consist- 

 ing merely of a few square inches of copper and zink, and a few 



