You make me very happy by the near prospect of seeing you and Sir John Pringle at Leeds. I shall be intirely at liberty to receive you, and I hope you will contrive to stay as long as possible in this town and neighbourhood. I thank you for the Native of New England. I had casually seen the same paper, and was particularly struck with it, without having any suspicion of Poor Richard being the author of it. I am obliged to you for your advice with respect to the dedication, and shall comply with it, but some other alterations, besides what you noted, must be made in it, if it be addressed to Lord Sandwich only.

I am intent upon the prosecution of my experiments on air; and since I wrote to you have observed several remarkable appearances. That very extraordinary kind of air, which Dr. Hales got from Walton Pyrites, and which I had despaired of procuring; I get from all the metals I have yet tried and by means of spirit of nitre. It is quite transparent, but a mixture of it and common air is red for a considerable time, in which the whole quantity is greatly reduced in bulk. A mixture of this and fixed air is not turbid. This air alone is reduced above one half by a mixture of iron filings, and brimstone standing in it, whereas common air is diminished only about one fifth by the same process. When I have the pleasure of seeing you I shall acquaint you with some other remarkable properties of this new kind of air. In the mean time, you will do me a very important service by procuring me, and bringing along with you a little of highly concentrated marine acid. There is none to be got here; and using a weaker sort in the solution of gold (in order to observe what kind of air came from it) I was obliged to apply a considerable degree of heat, the consequence of which was that the acid menstruum suddenly boiling, my hands, face, clothes, and the walls of the room have been great sufferers by it, as, I am afraid, I shall be able to show you. A penny-weight of gold, which I had bought for the purpose, was also lost. As a reward for this damage, I preserved about three ounce measures of air extracted from gold, which, I believe, was never seen before, and have the prodigious satisfaction of finding that it has the very same properties with that which is produced from copper. If I had studied poor Richard in time, I should not have indulged myself in these expences, but bad habits are not easily corrected. If, however, the passion be not kept up by considerable success, frugality, and an attention to a growing family will, at length, get the better of experimenting, and then I shall write nothing but Politicks, or Divinity, to furnish the bishop of Landaff with more quotations for his future invectives against the Dissenters.

The French translation of my History of Electricity I borrowed of M. Walsh; but as it will be of some use to me in a future edition of my work, I think to purchase it. In the mean time, M. Walsh will have no objection to your having it for what time you please, and I can give it you when you are here.

I am suprised that the French electricians should not have been able to provide themselves with better machines. I am confident that plates will never answer so well as globes or cylinders. I am, with my respectful compliments to Sir John Pringle, Dear Sir, yours sincerely