402 I'HILOSOPHICAL TRANSACTIONS. [aNNO 1 730 



ring of thin brass on the top of the lens, not only to keep it in steady, but to 

 prevent the pin from going in between the lens and the ferule, which spoils it* 

 point. 



The observations made by. Mr, Savery, are as follow : 



That the two opposite parts of a loadstone attract most vigorously, and are 

 called its poles. The middle between its two poles does not attract at all, and 

 may be called its equinoctial ; and from either pole to the middle, the attracting 

 force gradually abates. 



That there is no difference, that he could find, between the force of strength 

 of attraction and that of repulsion in the same pole of any loadstone or magnet, 

 unless when a small one approaches so near to a large one, as to have its polarity 

 more or less diminished by it. 



These properties convince him, that there is no such thing in nature as mag- 

 netical attraction without polarity, which is constituted of attraction and re- 

 pulsion ; and these two powers being always equally strong in the same pole of 

 every magnet, he thinks it a plain contradiction, to say this or that loadstone 

 has a strong attraction, but a weak polarity or direction. 



That no interposed body whatever, unless it be magnetical, though the most 

 solid in nature, was ever known in the least to impede or divert any of the 

 effects of a magnet ; but it is always found to attract magnetical bodies full as 

 powerfully at the same distance, as if nothing at all was between. 



That every frustum of a loadstone is an entire or perfect loadstone, having in 

 itself both poles as the whole stone had ; and that the poles in each frustum 

 have their direction, as near as the figure of it will admit, in the same parallel 

 line in which they were directed both in it and the whole stone, before it was 

 separated : for the polarity of every fragment is usually, if not always, before 

 they are separated, parallel to that of the whole stone, and consequently to that 

 of each other : and if ever it is found otherwise, Mr. S. thinks that loadstone 

 wants of perfection. So that the parts of any magnet, when cut in two trans- 

 versely, or perpendicular to its axis, become complete magnets, having each 

 their poles and axis parallel to the whole magnet ; and that, whether the two 

 parts are equal or unequal. And the sum of the weights of iron, lifted by the 

 two parts separately, is greater than the single weight lifted by the whole 

 magnet. 



That all magnetical attraction (as also repulsion) is mutual ; for iron or steel 

 attracts the loadstone, as that does iron or steel, and they also each other. 



That every loadstone communicates virtue to iron or steel, not only by con- 

 tact, but even by their approach within its attractive sphere, more or less as 

 nearer to, or farther from its body ; and likewise its poles, also according to the 



