What he will need is some scales, and a circular piece of something. If he has very acurate scales, this could be a piece of paper. Weigh the whole piece and let that weight represent 100gallons. (Say this weighs 300 carat (you introduced the use of irrational measurements))

Then cut off a "cap" of the circle by cutting a straight cut which is a 1/2 radius from the edge. Then weigh this piece, and that will tell you the remaining amount. (Say this weighs 15 carat, you'll then know this is 1/20 of the tank or 5 gallons)

<a href=http://empeg.comms.net/files/165974-gallons.gif> Picture </a>

The only thiung I learned in chemistry class is that chemistry people don't like mathematics. So, when we wanted to find the integral of a function, we drew the graph on a piece of paper, and cut out and weighed the graph to find its area.



Marius (Escort Cab + Mark II)