From Benjamin Franklin to William Franklin, 19 August 1772: extract
To William Franklin
Extract:2 Library of Congress
London Augt. 19: 1772
In yours of May 14th, you acquaint me with your indisposition, which gave me great concern. The resolution you have taken to use more exercise is extremely proper, and I hope you will steadily perform it. It is of the greatest importance to prevent diseases; since the cure of them by physic is so very precarious. In considering the different kinds of exercise, I have thought that the quantum of each is to be judged of, not by time or by distance, but by the degree of warmth it produces in the body: Thus when I observe if I am cold when I get into a carriage in a morning, I may ride all day without being warmed by it, that if on horse back my feet are cold, I may ride some hours before they become warm; but if I am ever so cold on foot, I cannot walk an hour briskly, without glowing from head to foot by the quickened circulation;3 I have been ready to say, (using round numbers without regard to exactness, but merely to mark a great difference) that there is more exercise in one mile’s riding on horseback, than in five in a coach; and more in one mile’s walking on foot, than in five on horseback; to which I may add, that there is more in walking one mile up and down stairs, than in five on a level floor. The two latter exercises may be had within doors, when the weather discourages going abroad; and the last may be had when one is pinched for time, as containing a great quantity of exercise in a handful of minutes. The dumb bell is another exercise of the latter compendious kind; by the use of it I have in forty swings quickened my pulse from 60 to 100 beats in a minute, counted by a second watch: And I suppose the warmth generally increases with quickness of pulse.
To Governor Franklin. New Jersey
2. In WTF’s hand. We are convinced that this and the following document are both extracts from one and the same letter. Our reason is partly that BF almost never wrote twice to the same correspondent on the same day, and primarily that in WF’s reply below, Oct. 29, he acknowledged the receipt of a long letter of Aug. 19. If we are right, WTF separated the two when dividing BF’s letters into categories by subject matter in the Memoirs, II, 10–11, 171–3; later editors, although they printed the extracts next to each other, treated them as distinct. We are compelled to do the same because we do not know which belongs first. WF’s quoting in his reply a phrase of his father’s and referring to an addition of Aug. 24, both of which are now missing, prove that we have only parts of what BF wrote.
3. Eight years later BF amplified this passage in his famous dialogue with the gout; see Smyth, Writings, VIII, 157–8.