During the greatest Part of the Time, I lived in the same House with my dear deceased Friend, your Mother; of course you and I saw and convers'd with each other much and often. It is to all our Honours, that in all that time we never had among us the smallest Misunderstanding. Our Friendship has been all clear Sunshine, without the least Cloud in its Hemisphere. Let me conclude by saying to you, what I have had too frequent Occasions to say to my other remaining old Friends, "The fewer we become, the more let us love one another."
On the back of the last letter, dated July 24, 1782, that he received from Mrs. Stevenson, he indorsed this memorandum: "This good woman, my dear Friend, died the first of January following. She was about my Age."
But the closest friendship that Franklin formed in England was with Mary, or Polly, Stevenson. To her, perhaps, the most delightful of all his familiar letters were written—letters so full of love and watchful interest as to suggest a father rather than a friend. It is not too much to say that they are distinguished by a purity and tenderness of feeling almost perfect, and by a combination of delicate humor and instructive wisdom to which it would be hard to find a parallel. The first of them bears date May 4, 1759, and the last bears date May 30, 1786. That the letters, some forty-six in number, are not more numerous even than they are is due to the fact that, during the period of their intercourse, the two friends were often under the same roof, or, when they were not, saw each other frequently.
In his first letter, addressed to "My Dear Child," Franklin tells Polly, who was then about twenty years of age, that he had hoped for the pleasure of seeing her the day before at the Oratorio in the Foundling Hospital, but that, though he looked with all the eyes he had, not excepting even those he carried in his pocket, he could not find her. He had, however, he said, fixed that day se'nnight for a little journey into Essex, and would take Mrs. Stevenson with him as far as the home of Mrs. Tickell, Polly's aunt, at Wanstead, where Polly then was, and would call for Mrs. Stevenson there on his return. "Will," he says in a postscript, "did not see you in the Park." Will, of course, was his son. In the succeeding year, he writes to Polly that he embraces most gladly his dear friend's proposal of a subject for their future correspondence, though he fears that his necessary business and journeys, with the natural indolence of an old man, will make him too unpunctual a correspondent.
But why will you [he asks], by the Cultivation of your Mind, make yourself still more amiable, and a more desirable Companion for a Man of Understanding, when you are determin'd, as I hear, to live single? If we enter, as you propose, into moral as well as natural Philosophy, I fancy, when I have fully establish'd my Authority as a Tutor, I shall take upon me to lecture you a little on that Chapter of Duty.
He then maps out a course of reading for her, to be conducted in such a manner as to furnish them with material for their letters. "Believe me ever, my dear good Girl," he concludes, "your affectionate Friend and Servant."
With his next letter, he sends her a gift of books, and begs her to accept it, as a small mark of his esteem and friendship, and the gift is accompanied with more specific advice as to the manner in which she was to prosecute her studies, and obtain the benefit of his knowledge and counsel. When he writes again, his letter discloses the fact that a brisk interchange of ideas had been actually established between them. "'Tis a very sensible Question you ask," he says, "how the Air can affect the Barometer, when its Opening appears covered with Wood?" And her observation on what she had lately read concerning insects is very just and solid too, he remarks. The question he has no difficulty in answering, and the observation on insects leads to some agreeable statements about the silk-worm, the bee, the cochineal and the Spanish fly, and finally to an interesting account of the way in which the great Swedish naturalist, Linnæus had been successfully called in by his King to suggest some means of checking the ravages of the worm that was doing such injury to the Swedish ships. Nor was all this mellifluous information imparted without a timely caution.
There is, however [he concluded], a prudent Moderation to be used in Studies of this kind. The Knowledge of Nature may be ornamental, and it may be useful; but if, to attain an Eminence in that, we neglect the Knowledge and Practice of essential Duties, we deserve Reprehension. For there is no Rank in Natural Knowledge of equal Dignity and Importance with that of being a good Parent, a good Child, a good Husband or Wife, a good Neighbour or Friend, a good Subject or Citizen, that is, in short, a good Christian. Nicholas Gimcrack, therefore, who neglected the Care of his Family, to Pursue Butterflies, was a just Object of Ridicule, and we must give him up as fair Game to the satyrist.
A later letter is an amusing illustration of the manner in which he occasionally reminded his pupil that she must not take herself and Philosophy too seriously. Polly was at the time at the famous Wells of Bristol about which so much of the social pageantry of the eighteenth century centred.
Your first Question, What is the Reason the Water at this place, tho' cold at the Spring, becomes warm by Pumping? it will be most prudent in me to forbear attempting to answer [he said], till, by a more circumstantial account, you assure me of the Fact. I own I should expect that Operation to warm, not so much the Water pump'd, as the Person pumping. The Rubbing of dry Solids together has been long observ'd to produce Heat; but the like Effect has never yet, that I have heard, been produc'd by the mere Agitation of Fluids, or Friction of Fluids with Solids.