“A Whisky Puzzle”


In 1895 a London shopkeeper attracted customers with a glass cask of whiskey — they were puzzled to find that no matter how much liquid they drew off, the level in the cask never dropped. The container could be viewed from any angle, and it stood well away from the wall. How was this possible?

A hidden pipe connected the bottom of the cask to a tank in another room. When a customer drew a glass of whisky, a confederate there would open a tap to replenish tank B, and the liquid, seeking its own level, would maintain the same height in the cask.

(James Scott, “Shopkeepers’ Advertising Novelties,” Strand, November 1895. See Desert Downpour.)

Black and White

crypton chess puzzle

An old puzzle by Paul Hoffman from Science Digest. Dr. Crypton is playing chess with his boss. Crypton has the white pieces. What move can he play that will not checkmate Black? There’s no funny business; the problem is just what it seems, except that Crypton has promised never to put a knight on any square adjacent to the black king, so 1. Ne6 doesn’t count as a solution.

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Empty Vessel

A puzzle by Soviet science writer Yakov Perelman: A bottle full of gasoline has a mass of 1,000 grams. The same bottle filled with acid has a mass of 1,600 grams. The acid is twice as dense as the gasoline. What’s the mass of the bottle?

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Win Count

Imagine a game of tic-tac-toe (noughts and crosses) played in three dimensions in an 8×8×8 cube. A player wins by marking some straight line of eight cells through the large cube. How many such winning lines are there?

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“Three Threes Are Ten”

This little trick often puzzles many:–

Place three matches, coins, or other articles on the table, and by picking each one up and placing it back three times, counting each time to finish with number 10, instead of 9. Pick up the first match and return it to the table saying 1; the same with the second and third, saying 2 and 3; repeat this counting 4; but the fifth match must be held in the hand, saying at the time it is picked up, 5; the other two are also picked up and held in hand, making 6 and 7; the three matches are then returned to the table as 8, 9, and 10. If done quickly few are able to see through it.

— John Scott, The Puzzle King, 1899

04/20/2024 Reader Vladamir Tsepis adds, “This reminds me of the way to convince children you have 11 fingers. Start by showing your left hand splayed, curl down the thumb and index finger counting ‘one, two…’, then of the remaining say ‘let’s skip these three’. Move to your right hand, bend each finger in turn as you count ‘four, five, six, seven, eight…’. Return to the left hand counting off the three we skipped ‘nine, ten, eleven.'”


From The Book of 500 Curious Puzzles, 1859:

Following is the epitaph of Ellinor Bachellor, an old pie woman. How should we read it?

Bene A. Thin Thed Ustt HEMO. Uld yo
L.D.C. RUSTO! Fnel L.B.
Ach El Lor. Lat. ELY,
Wa. S. shove N. W. How — Ass! kill’d I. N. T. H.
Ear T. Sofp, I, Escu Star.
D. San D T Art. San D K. N E. W. E
Ver — Yus E. — Oft He ove N, W. Hens He
‘Dli V’DL. on geno
Ug H S hem A.D.E. he R. la Stp. Uf — fap
Uf. F. B Y he. R hu
S. Ban D. M.
Uch pra is ‘D. No. Wheres Hedot
HL. i. e. Tom. A kead I.R.T.P. Yein hop Esthathe
L L B. Era is ‘–D!

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Counting Up

A problem from Daniel J. Velleman and Stan Wagon’s excellent 2020 book Bicycle or Unicycle?: A Collection of Intriguing Mathematical Puzzles:

A square grid measures 999×999. Each square is either black or white. Each black square that’s not on the border of the grid has exactly five white squares among its eight immediate neighbors (those that adjoin it horizontally, vertically, or diagonally). Each white square that’s not on the border has exactly four black squares among its immediate neighbors. Of the 999 × 999 = 998001 squares in the grid, how many are black and how many white?

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A puzzle by Soviet science writer Yakov Perelman: Six carpenters and a cabinetmaker were hired to do a job. Each carpenter was paid 20 rubles, and the cabinetmaker was paid 3 rubles more than the average wage of the whole group. How much did the cabinetmaker make?

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Mass Transit

A problem from the October 1964 issue of Eureka, the journal of the Cambridge University Mathematical Society:

The planet Kophikkup is in the shape of a torus or ring-doughnut. There is a direct mono-rail line from each of the four space-ports to each of the major cities. No lines join or cross. What is the greatest possible number of major cities? Draw a diagram for this case.

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