466 PHILOSOPHICAL TRANSACTIONS. [aNNO IJOQ. 



and no more ; this magnet, (supposing it to be in every part of equal virtue) 

 when separated and broken into a number of very small parts, and these 

 dressed and armed according to art, will then be capable of suspending 50 or 

 100 times more the weight of iron among them, now separate, than they could 

 when all in one mass; whence it appears, that the attractive quality of the 

 stone seems to be increased in proportion, as its superficies is to its bulk of 

 matter: so, by the third experiment, I found that the greater quantity of matter 

 in one vessel, more than in the other, contributed nothing to the ascent of 

 the water, which seemed wholly to depend on the largeness or the smallness 

 of their cavities, as to the height it would rise in them ; and as their cavities 

 are lessened, so the disproportions of their inward surfaces to their cavities are 

 increased. 



And as the magnet, when broken into the said number of small parts, will 

 attract more, than when united in one mass, and is no more than separating, 

 or working the thick body of glass into a number of small tubes, that is mul- 

 tiplying the surfaces ; the water then would rise in each of them singly, as it 

 would when all in one body, its cavity being the same with the others; by 

 which means, the quantity of water ascending in them is augmented from the 

 same quantity of matter. 



To conclude : There seems to be such an agreement in the qualities or dis- 

 positions of one with the other, that I see no reason why the facts proceed not 

 from one and the same cause ; for as the inner surfaces of the tubes are made 

 smaller and smaller, so the power of their attraction (as is visible by the higher 

 ascent of the water in them) is greater and greater, and is most demonstrable 

 by the experiments of the planes ; for their inner area being always the same, 

 so that as they are placed nearer and nearer to each other, the cavity or space 

 between them becomes less and less, and consequently the disproportions are 

 increased, by which the power of their attraction is augmented. 



ExPER. IV. I took a glass tube, about 32 inches long, the diameter of its 

 cavity near three quarters of ah inch : this I filled at one end with ashes, finely 

 sifted, having first tied a piece of linen cloth over the other, to prevent their 

 falling out. At every small portion I put in, I rammed them strongly down 

 with a rammer, whose basis was very little less than the bore of t"he tube; by 

 which means 1 crouded the ashes as close together as possible. When the tube 

 was full, I tied over that end of it by the neck a small and limber bladder, 

 having first expressed all the air out of its body, in order to receive that air, 

 which I expected would be forced through the ashes on the ascent of the water. 

 In this manner I plunged the end of the tube, to which I had tied the linen, 

 iinder the surface of water in a glass, and found the water presently begin to 



