Henry Ernest Dudeney/Modern Puzzles/183 - At the Brook

by : $183$

 * At the Brook
 * In introducing liquid measuring puzzles in my book, I have said,
 * "It is the general opinion that puzzles of this class can only be solved by trial,
 * but I think formulæ can be constructed for the solution generally of certain related cases.
 * It is a practically unexplored field for investigation."
 * So far as I know, the hint has not been taken and the field is still unexplored,
 * so I recently took advantage of a little unexpected leisure to look into the matter.
 * The result, as I thought probable, was that I struck some new and very interesting things.


 * Let us take the simplest possible case of a man who goes to a brook with only two vessels with which to measure a given quantity of water.
 * When we are dealing, say, with a barrel of wine we may have complications arising from the barrel being full or empty,
 * from its capacity and contents being known or unknown,
 * from waste of wine being permitted or not permitted,
 * and from pouring back into the barrel being allowed.
 * All these points are eliminated.
 * Is it then possible that any puzzle remains? Let us see.


 * A man goes to the brook with two measures of $15$ pints and $16$ pints.
 * How is he to measure exactly $8$ pints of water, in the fewest possible transactions?
 * Filling or emptying a vessel or pouring any quantity from one vessel to another counts as a transaction.


 * The puzzle is not difficult, but I think the reader will find it very entertaining and instructive.
 * I need hardly add that no tricks, such as marking or tilting the vessels, are allowed.