Letter 25: Aeneas asks Julian to finish improving a clever water machine.

I think I possess the garden of Alcinous because of the fine machine that you invented and the carpenter made. I will describe it in words, since the sight is delightful. There are two very large wheels joined with boards and pegs so that to those watching from outside they seem to be one. On the platform a track runs inside, making a long course around the same place, and the wheel moves along with it as far as the track wishes. The axle around which the great wheel turns in place also moves another, smaller wheel over the well. Ropes and jars are attached to this in sequence. The motion is extremely swift, but the middle of the small wheel is cramped and receives only the first part of the outflow; most of the water pours back into the well and, sinking again, is brought up only with difficulty. This, then, must be corrected. For the person who discovered the beginning, the ending is not hard. Let us not allow so fine a spectacle to need another man's wisdom, and let us not suffer the same thing as a painter who beautifully paints Helen but forgets her head.