VOL, XXXVII.] PHILOSOPHICAL TRANSACTIONS. 541 



pi. 14, brightly polished at A, and taper at the other end. Then with one 

 hand he held the piece of steel fast down on the anvil, and with the other he 

 held the iron bar perpendicular with it, with its point a on the steel, and 

 pressing hard, he rubbed the steel with the iron bar towards himself, from 

 north to south, several strokes, always carrying the bar far enough round about 

 to begin again at the north, to prevent the drawing back of the magnetical 

 force: having thus given 10 or 12 strokes, he turned the steel upside down, 

 having it in the same position as to north and south ; and after rubbing and 

 turning it, till he rubbed it about 400 times, it received by degrees more and 

 more strength, and at last had as much- as if it had been touched by a strong 

 loadstone. The place where he began to rub, was always that which pointed to 

 the north, when the needle was hung, the end where he had ended the stroke 

 turning to the south. Sometimes it has happened, that in a few strokes he 

 gave the steel its virtue ; nay even in the very first stroke one may give a great 

 deal to a small needle. 



In this way M. Marcel communicated the magnetical virtue to needles of sea- 

 compasses, made of one piece of steel, as fig. 3, so strongly, that one of the 

 poles would take up 4^, and the other a whole ounce of iron, though these 

 needles were anointed with linseed oil, which made a hard coat, to keep them 

 from rusting ; yet they retained the virtue : but in strengthening this sort of 

 needles, he rubbed by turns first to the right, and then to the left side. 



The same way he brought the virtue into the point of a knife ; so that it 

 would sustain 1 ounce and ^. 



He brought the said virtue into 4 small pieces of steel, each 1 inch long, 

 and -rV inch broad, as thin as the spring of a watch. Rejoined these 4 pieces 

 together, as into an artificial loadstone, weighing 18 grains troy; and then it 

 drew up and sustained an iron nail, which weighed 144 grains troy. This arti- 

 ficial loadstone was for 6 years tumbled about, and lay among iron and steel, 

 and in any position ; and yet it rather acquired more, than lost any of its 

 virtue. 



The magnetical virtue being thus communicated to iron or steel, he further 

 observed, that that end where the stroke was begun, would draw to the north, 

 and where the stroke ended to the south, in whatever situation the steel had 

 been laid on the anvil to give it the virtue. He took a piece of steel, and 

 rubbed it from one end to the middle ; and then from the other end to the 

 middle, and found it had 1 north poles, one at each end, and the noddle a 

 south pole. 



Further, beginning to rub from the middle towards each end, of another 



