406 I'HILUSOPHICAL TRANSACTIONS. [aNNO IJSO. 



'^and after the same manner touched the first bar with the second, as he had 

 touched the second with the first. And when by trial with the compass needle 

 he found the armed bar had communicated to the other more virtue than was 

 in itself, he took off the armour, and bound it to that which was newly touched, 

 and thus retouched that which he had disarmed. In a few repetitions of chang- 

 ing the armour from bar to bar, and touching the weakest, he procured in both 

 of them, without any other assistance, a fixed polarity to such a degree, as that 

 the north pole, or unmarked end of either of them held downward, would at- 

 tract the north end of the needle, though much fainter than if the north pole 

 of the bar had been upward, and position did not now change their polarities, 

 but only weaken them: therefore he now calls their virtue perfectly permanent. 

 Four or five repetitions more increased their virtue to such a degree, that the 

 south pole of one of them would lift a ten-penny nail prepared ; and after 2 or 



3 repetitions more, a common door key of an iron box lock, weight Troy $j 

 and above gij, not by the bow, but by its lower end, which was wrought some- 

 what globular and polished. 



In the last place he got a piece of inch deal, above 3 inches broad, and 7 or 

 8 feet long ; in the middle of which, at about 5 or 6 inches from one end, he 

 made a hole through with a large gimlet, into which he drove an iron or steel 

 pin, whose length, besides what went into the wood, was a little less than the 

 thickness of one of the bars. He then placed the largest bar on the said board, 

 with its marked end close to the pin, and its length parallel to that of the board, 

 and with an awl made 4 small holes in the board, one of them on each side of 

 the bar, about an inch from the bottom, and about the thickness of a sixpence, 

 from its sides, and the other two after the same manner, about an inch from 

 the top. He drove into them pins of large wire half an inch long, besides 

 what was in the board, to keep the bars from sliding out of their places in 

 touching. Then removing that, and placing any other bar between the said 

 pins, with its marked end close against the great pin, he placed the marked end 

 of the said largest bar close against the unmarked end of the other, and made 



4 holes on its sides, and drove pins in them as before; and so continued to do 

 until the board was full. It held half a dozen bars. He took care to place the 

 marked end of every bar directed towards the great iron pin which was to keep 

 them from sliding down to the ground, when the other end of the board was 

 elevated, to stand in the magnetical line. 



The board standing with one end on the ground, and the other leaning 

 against the wall, at the south end of the room, he took the armed bar, which 

 had virtue, and placed its north pole's armour about the middle of the highest 

 bar, keeping the armour of the south pole a little upon one side of the bars. 



