696 PHILOSOPHICAL TRANSACTIONS. [anNO 17 12. 



of the living fossil muscles attested, and signed, by the four persons present 

 at the finding them ; so that nothing but its being a singular instance makes me 

 scruple the relation : but the labourers have such a character for veracity, that 

 I rather incline to believe it. 



Experiments showing the Proportion of the Power of the Loadstone at different 

 Distances. By Mr. Fr. Haukshee, F.R.S. N° 335, p. 506. 



I took a quadrant of 4 feet radius ; and having fixed it to the floor, in the 

 position of the needle, whose south point directed itself to no degrees, I then 

 fixed a board likewise on the floor, in a direct angle from the same ; the gra- 

 duations on the board being 3 inches distant from each other. The needle was 

 suspended on a point arising from the centre of the quadrant, from whence the 

 several stations of the magnet were measured. The magnet was laid on a thin 

 piece of board; under which to one side was nailed a narrow slip of wood 

 to slide it along the side of the graduated board, by which the stone might be 

 always kept in the same direction to the needle. The stone used was about 6 

 pounds weight ; it was rough, and of an irregular figure; yet I could discover 

 no inconveniency thence arising in the experiment, it being, and acting at all 

 distances in the same position, as first placed on the board : and I have several 

 times observed, that the proportions of its power will be regular, and agreeable 

 to the several distances: for when the stone has been diff^erently posited on the 

 forementioned thin board, different angles of the needle would ensue at the 

 same stations ; yet their proportions to each other would be nearly the same. 

 My meaning is this: suppose the stone was so placed, as at 3 inches from the 

 needle it would give the needle an angle of go degrees, the stone being con- 

 tinued in the same direction at the several stations, the proportions of its 

 power to each other would be much the same, as if the angle of the needle at 

 the first beginning made only 87, or even but 80 degrees, on the quadrant ; 

 for on a small alteration of the poles of the stone, such diversity of angles 

 will arise. 



In these experiments I made use of two needles ; one of a radius of 6 inches 

 the other but of one inch : which last, after abundance of trials, I found to be 

 most accurate; besides the advantage it gave in beginning the experiment 6 

 inches nearer the stone, than the other: and from 2 feet distance from the 

 same, it became nearly agreeable to the angles made by the long needle, to all 

 the farther distances; as you will find by the following tables, which were made 

 with the several needles in the same direction of the stone. I measured the 

 angles by a silk thread strained directly over the needle to that part of the 

 quadrant to which it was directed; which was the best way I could contrive to 

 come nearest the truth. 



