From Mary Stevenson
Draft: American Philosophical Society
Bromley June 11. 1762
Whether the Invitation you give me to write to you proceeds from the Pleasure you receive or desire to bestow I shall not enquire;1 the first would gratify my Vanity most, but I am not less pleas’d with thinking you love to indulge me.
When I say I have not Leisure for my favourite Amusements I am as much surpriz’d as you can be, and I wonder how my Time passes away without any Employment that appears of Consequence. Day after Day I have intended to furnish my Mind with something that would serve for the Subject of a Letter to you; but Day succeeded to Day without the Acquisition, and I now sit down to write with very little in my Head tho much in my Heart.
I have taken the Liberty you gave me of transcribing your Letter on Fire,2 which gives a clearer Explication of it’s Effects than I ever met with, yet some Questions remain for me to ask. Whence is it that Fire is increased by the Impulsion of the Air, yet if that Impulsion is too strong it is extinguish’d? I have seen you blow out the Flame of the Bougie,3 and, by drawing it swiftly thro’ the Air, immediately rekindle it. Another Thing appears to me very unaccountable. To prevent the firing of Wheels we make use very effectually of those Materials which soonest catch fire as Pitch, Grease &c. Though I have acknowledg’d this to be unaccountable I have attempted to discover the Cause, but I cannot satisfy myself. I remember you told me no Degree of Heat was ever produc’d in Fluids by Friction. The Grease then being between the Nave and the Axle-tree of the Wheel prevents their rubbing against each other. You will give me Pleasure whenever you will satisfy me more fully, which you may not have Leisure to do by Writing, but as I hope for the Pleasure of seeing you once more it may serve for our Conversation, in the mean time I shall be glad of any Word you will condescend to send me.4
May you my Dear Saint enjoy all the Felicity you Promise yourself in the New World! and May it be long ere you are remov’d to that other World where only your Votary can hope to meet you!
Present my dutiful Affection to my Dear Mother, and Thanks for her kind Letter which I will soon repay. Our amiable Host5 left us last Tuesday. He intended waiting on you, and if he did would tell you I receiv’d your elegant affectionate Letter. Those were his Words when he return’d it to me, for my Vanity made me shew it. Every Testimony of your Regard is too high a Honour not be felt and made the Boast of Dear Sir your most grateful and affectionate humble Servant
1. For BF’s “Invitation” to Polly to write him a “philosophical Epistle” and for some of the other matters mentioned in this letter, see above, p. 102.
3. A wax candle which took its name from the North African town whence it was first imported into Europe.
4. See below, pp. 105–8.
5. Dr. John Hawkesworth.