For the compass, take wax and oil.

A petition that I ask of my readers.

I wish it to be granted me that the line which goes from the object to the eye, through the same quality of air, is straight.

If I propose lines of a plane, for various qualities of obliquity, I understand them to be straight. If I speak of round bodies moving upon these planes, [I ask] that they be understood as perfect.

Among the other superfluous and impossible credulities of men I have found the search for continuous motion, which by some is called the perpetual wheel. This has held for very many centuries, with long searching and experiment and great expense, occupying almost all those men who delight in contrivances of water and of war and other subtle devices. And always in the end it befell them as it did the alchemists: that for a small part the whole was lost. Now I intend to give this alms to this sect of investigators, that is, to give them so much rest in such a search as this little work of mine shall last. And besides this, whatever they promise of themselves to others shall have its desired end, and they will not always have to be in flight because of the impossible things promised to princes and rulers of peoples. I remember having seen many, from various countries, who through their puerile credulity had betaken themselves to the city of Venice with great hopes of profit, to make mills in dead water; and who, being unable after much expense to move such a machine, were forced to move themselves out of such air with great fury.

That is, to raise the still water with instruments — as from a marsh, a well, or the sea — and this raised water, in its descending, to be put to use to do as the other water does at the mills. O simpletons, or truly men without natural [reason]... what is it you want?

Whoever denies the reason of things publishes his own ignorance.

If it were possible to make a bombard whose ball were the world, and since a bombard throws a ball of one braccio 3 miles — so that one may measure such a course of 9000 braccia, that is, 9 thousand balls — we can therefore say that such a bombard would throw our world nine thousand times the size of the diameter of that world distant from itself. [They] would be at seven thousand miles per world; they would be 63 thousand miles.

If you do not wish to make [it] of bronze, so that they be not carried off, know that all the good things of Rome were spoils of cities and lands conquered by those Romans. And it was of no avail to be of marvellous weight, as was the obelisk and the two horses. And if you have it made so clumsy that it cannot be carried away, they will make walls and mortar of it. Do as you please, for everything has its death. And should you tell me that you do not wish to make a thing that gives more honour to the craftsman than to the one who spends, know that most things give more honour to their maker than to the payer.