A man pulling a [dead] weight balanced against himself cannot pull more than his own weight.
 Leonardo da Vinci, The Notebooks of Leonardo Da Vinci (1478 – 1519). copy citation

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Author Leonardo da Vinci
Source The Notebooks of Leonardo Da Vinci
Topic balance weight
Date 1478 – 1519
Language English
Reference
Note Translated by Jean Paul Richter in 1888
Weblink http://www.gutenberg.org/cache/epub/5000/pg5000-images.html

Context

“If you have to draw a man who is in motion, or lifting or pulling, or carrying a weight equal to his own, in what way must you set on his legs below his body? [Footnote: In the MS. this question remains unanswered.] 383. OF THE STRENGTH OF MAN. A man pulling a [dead] weight balanced against himself cannot pull more than his own weight. And if he has to raise it he will [be able to] raise as much more than his weight as his strength may be more than that of other men. [Footnote 7: The stroke at the end of this line finishes in the original in a sort of loop or flourish, and a similar flourish occurs at the end of the previous passage written on the same page.” source