There are some half-dozen puzzles, as old as the hills, that are perpetually cropping up, and there is hardly a month in the year that does not bring inquiries as to their solution.  Occasionally one of these, that one had thought was an extinct volcano, bursts into eruption in a surprising manner.  I have received an extraordinary number of letters respecting the ancient puzzle that I have called “Water, Gas, and Electricity.”  It is much older than electric lighting, or even gas, but the new dress brings it up to date.  The puzzle is to lay on water, gas, and electricity, from W, G, and E, to each of the three houses, A, B, and C, without any pipe crossing another.  Take your pencil and draw lines showing how this should be done.  You will soon find yourself landed in difficulties.

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252.—­A PUZZLE FOR MOTORISTS.

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Eight motorists drove to church one morning.  Their respective houses and churches, together with the only roads available (the dotted lines), are shown.  One went from his house A to his church A, another from his house B to his church B, another from C to C, and so on, but it was afterwards found that no driver ever crossed the track of another car.  Take your pencil and try to trace out their various routes.

253.—­A BANK HOLIDAY PUZZLE.

Two friends were spending their bank holiday on a cycling trip.  Stopping for a rest at a village inn, they consulted a route map, which is represented in our illustration in an exceedingly simplified form, for the puzzle is interesting enough without all the original complexities.  They started from the town in the top left-hand corner marked A. It will be seen that there are one hundred and twenty such towns, all connected by straight roads.  Now they discovered that there are exactly 1,365 different routes by which they may reach their destination, always travelling either due south or due east.  The puzzle is to discover which town is their destination.

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Of course, if you find that there are more than 1,365 different routes to a town it cannot be the right one.

254.—­THE MOTOR-CAR TOUR.

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In the above diagram the circles represent towns and the lines good roads.  In just how many different ways can a motorist, starting from London (marked with an L), make a tour of all these towns, visiting every town once, and only once, on a tour, and always coming back to London on the last ride?  The exact reverse of any route is not counted as different.

255.—­THE LEVEL PUZZLE.

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This is a simple counting puzzle.  In how many different ways can you spell out the word LEVEL by placing the point of your pencil on an L and then passing along the lines from letter to letter.  You may go in any direction, backwards or forwards.  Of course you are not allowed to miss letters—­that is to say, if you come to a letter you must use it.