VOL. XVI.] PHILOSOPHICAL TRANSACTIONS. 383 



had concerning the position of the stone at the time when its pole had formerly 

 been determined; I concluded that this former pole was distant from the point 

 I call the true pole 13* towards the east, in the place where it had been marked, 

 and which is unknown to me, since that at this time, in this country, the 

 needle varies about 3° westward. 



On this hypothesis I have invented a new sort of needle for the compass, 

 which may have the same alterations as a spherical loadstone, and at the same 

 time the same conveniences as the ordinary needle. I caused a ring of 3 

 inches diameter to be made of steel wire, from which issued three radii of very 

 fine brass wire, meeting at the centre in a cap perfectly like that of an ordinary 

 compass, that so this circle might rest on a pin in its centre, and be at full 

 liberty to turn round, its centre being fixed. This done, I gave the magnetical 

 touch to this steel ring, by applying indifferently to a point of it one of the 

 poles of a strong loadstone, and the other pole of the stone to the opposite 

 point, to give the greater virtue to the ring. The ring then became strongly 

 magnetical, and the point called the south pole readily turned itself towards the 

 north, and after several vibrations stopped there; and it had also the same 

 inclination towards the pole which is found in needles after they have been 

 touched. Lastly, I fixed upon the ring a small fieur-de-lis of brass, in the 

 point which exactly respected the north, the ring being first well settled. 



If the poles of the magnetic virtue in the loadstone change after the same 

 manner as they do on the earth, it seems likely that the same thing would 

 happen to this ring, and that one point thereof should always exactly respect the 

 north. But to inform myself if a steel ring had the same effects as a terrella, 

 I made the following experiment : having touched a steel ring and laid it on a 

 paper, I strewed the filings of steel upon it; and then gently shaking the paper, 

 I saw that the direction of the magnetical matter passed directly cross the ring 

 from one pole to the other, and that there were two vortices on the sides, as it 

 is observed in the spherical magnet, which seems very surprising ; for according 

 to the common hypothesis of the magnet, the magnetical virtue passing more 

 easily in the steel than in the air, should run on both sides of the pole round 

 the ring, and only form a pole opposite to the first. But I was further con- 

 firmed in this opinion by applying a fiat and pointed piece of iron, like the 

 blade of a knife, to a loadstone, so as the point of the iron reached beyond the 

 stone ; and having afterwards presented this point to the magnetical ring, I ob- 

 served that different points of this ring applied to the point of the iron, accord- 

 ing as the several parts of it had been applied to the stone ; which happens not 

 in the magnetical needle, for that always presents one of its ends to the point 

 of the iron, being not disposed, by reason of its length, to receive the mag. 



