How it is more difficult to understand the works of nature than a book by a poet.

n m f c h, 3 d 3

Here we speak of the balance n h, saying how the weight d, being sustained by the cords n c, gives so much more weight to n than to c as it is nearer to n than to c. And that this is true, see the weight d, which is 3 pounds, of which 2 load onto n and one onto c, making in this case no mention of the force, because that force does not weigh, and we shall reckon it separately from this. Now, to return, we shall say plainly that of the 3 pounds of d, 2 are at n and one at c. And the pole of the balance n h is twice as near to c as to n, whence the 2 of n will be balanced by 4 at c, that is, with three hooks and with the one that at that site is unloaded of the weight d. Now, in sum, remember to divide the simple weight of d from the simple force of the cords that suspend it according to the height of that site.

a b c d e, 6, 2, h, 4, 4 2, 6 o 8, 8, r, S, 8, K, 8 8

The weight r, although, being 8, it gives 4 and 4 of itself to its 2 supports, this is understood to be of the simple weight of 8 attached to them; but no mention is made of the accidental weight that the 2 cords acquire, since they are not perpendicular above.

Proof and final conclusion of this motion, proved by the experiment of the balance above. Now look through many experiments, whether they are all confirmed by the same reasoning, namely that the weights give to the extremities of the 2 cords that suspend them the same proportion as the bases of the 2 triangles that are formed between those two cords and the central line of the weight they sustain bear to one another. And make sure that the cords which pull are always in the line of the final motion of the weight that is being raised, that is, at a. For if they were farther outside that line, or farther inside, those bases of the triangles could not then be proportioned together, and the rule of the balance above would not serve. The angles made by the 2 cords begin at half a right angle and end at a whole right angle. It is half a right angle when at K. It is a whole right angle when at a. The cords that pull at a are made only to prove it true that the weight makes such a real change upon its supports as a peg or pin placed under the weight along the line of its motion would likewise make.