I received your Favour of the 12th. past, and congratulate you on the Recovery of Mrs. Winthrop and your Children from the Small Pox.

Mr. Stiles return’d Aepinus to me sometime since. I must confess I am pleas’d with his Theory of Magnetism. Perhaps I receive it the more readily on Account of the Relation he has given it to mine of Electricity. But there is one Difficulty I cannot solve by it quite to my Satisfaction, which is that if a Steel Ring be made magnetical by passing Magnets properly round it, and afterwards broken into two Semicircles, each of them will have strong N. and S. Poles, in whatever Part the Ring is broken. I have not try’d this, but have been assur’d tis so: and I know that a magnetic Bar broken has after Breaking 4 Poles, i.e. it becomes two compleat Bars. I think with him that Impermeability to the El. Fluid, is the Property of all El[ectric]s per se; or that, if they permit it to pass at all, it is with Difficulty, greater or less in different El[ectric]s per se. Glass hot permits it to pass freely; and in the different degrees between hot and cold may permit it to pass more or less freely.

I shall think of the Affair of your unfortunate College, and try if I can be of any Service in procuring some Assistance towards restoring your Library. Please to present my respectful Compliments to Dr. Chauncy, Mr. Elliot and Mr. Cooper; and believe me with sincere Esteem, Sir Your most obedient humble Servant