The New Thoughts of Galileo

This would not have happened to a small column, even if it were similar, both in thickness and in length, for which he gives the reason in his second day.

What seems marvelous is that one experiences that the strength of bodies usually grows more than their thickness, since a nail or a stick double the thickness of another is eight times stronger than the stick, and the nail is twice as strong. The author here notes the discrepancy between the strength of large versus small bodies, which he seeks to resolve through geometry. And yet we see that small animals are often stronger in proportion than the largest ones are. These are the difficulties from which he takes the occasion to discourse on the strength and the resistance of cylinders or columns, and to make of them a new science of Mechanics, as one will see in the following Articles.