More Dream Poetry

Lewis Carroll and Alfred, Lord Tennyson, became improbable acquaintances in the 1850s, a few years before Carroll published Alice’s Adventures in Wonderland. The young author sent a letter to his cousin, May 11, 1859, after one memorable visit to the laureate:

Tennyson told us that often on going to bed after being engaged on composition he had dreamed long passages of poetry (‘You, I suppose,’ turning to me, ‘dream photographs?’) which he liked very much at the time, but forgot entirely when he woke. One was an enormously long one on fairies, where the lines from being very long at first gradually got shorter and shorter, till it ended with fifty or sixty lines of two syllables each! The only bit he ever remembered enough to write down was one he dreamed at ten years old, which you may like to possess as a genuine unpublished fragment of the Laureate, though I think you will agree with me that it gives very little indication of his future poetic powers:—

May a cock-sparrow
Write to a barrow?
I hope you’ll excuse
My infantine muse.

(Lewis Carroll, “A Visit to Tennyson,” Strand, June 1901. See Pillow Verse and Night Work.)

The Schienenzeppelin,_Berlin,_Schienenzeppelin.jpg
Image: Wikimedia Commons

The land speed record for a petrol-powered rail vehicle was set way back in 1931, when aircraft engineer Franz Kruckenberg experimented with a “rail zeppelin” on German railway lines. An aircraft engine drove a rearward-facing propeller to accelerate a lightweight aluminum body to the startling speed of 230.2 km/h (143.0 mph), a railway record that held until 1954.

The vehicle evolved over a few years but was eventually dropped in favor of other high-speed designs.


In Jane Austen’s Pride and Prejudice, the residents of Meryton consider Mr. Darcy arrogant, proud, and conceited because of his reactions to village people. Of Elizabeth Bennet he says, “She is tolerable; but not handsome enough to tempt me; and I am in no humour at present to give consequence to young ladies who are slighted by other men.” Later, when she spurns his proposal, he tells her directly, “Nor am I ashamed of the feelings I related. They were natural and just. Could you expect me to rejoice in the inferiority of your connections? To congratulate myself on the hope of relations whose condition in life is so decidedly beneath my own?”

The trouble is, he’s right — Darcy is educated, intelligent, wealthy, and handsome. He is superior to the people he’s judging, even according to their own standards. University of Minnesota philosopher Valerie Tiberius asks, what then is arrogance?

“Henry Kissinger, for instance, is by all accounts a highly arrogant person, but his intellectual talents are considerable, and all philosophical accounts of the good life for human beings assign such talents an important role. … So if Darcy and Kissinger believe that they are doing pretty well by the standards of human excellence, it is not obvious that they are wrong, and their arrogance must therefore consist in something other than a false belief.”

(Valerie Tiberius and John D. Walker, “Arrogance,” American Philosophical Quarterly 35:4 [October 1998], 379-390.)

The Little People

In medieval chess, each of the eight pawns was associated with a commoner’s occupation. From king rook pawn to queen rook pawn:

  • Laborer (farmer)
  • Smith
  • Notary
  • Merchant
  • Physician
  • Innkeeper
  • City watchman or guard
  • Ribald or town courier

The merchant stood before the king, the doctor before the queen.

Jacopo de Cessolis used the game as the basis for a series of sermons on morality — he says that a philosopher invented the game to show his cruel king “the maners and conditicions of a kynge of the nobles and of the comun people and of theyr offices and how they shold be touchid and drawen. And how he shold amende hymself & become vertuous.”

(From Christopher Kleinhenz’s Medieval Italy: An Encyclopedia, 2004.)

Dues Process

A curious puzzle by Dartmouth mathematician Peter Winkler: You’ve just joined the Coin Flippers of America, and fittingly the amount of your dues will be decided by chance. You’ll name a head-tail sequence of length 5, and then a coin will be flipped until that sequence appears in five consecutive flips. Your dues will be the total number of flips in U.S. dollars; for instance, if you choose HHHHH and it takes 36 flips to produce a run of five heads, then your annual dues will be $36. What sequence should you pick?

At first it seems that it shouldn’t matter — any fixed sequence should have the probability (1/2)5, or 1/32. But “Not so fast,” Winkler writes. “Overlapping causes problems.” It is true that in an infinite sequence of random flips, the average distance between one occurrence and the next of any fixed sequence is 1/32. But if you choose HHHHH (for example), one occurrence of this outcome gives a huge head start to the next — if the next flip is a tail, then you’re starting over cleanly, but if it’s a head then you’ve already produced the next occurrence.

“If X is the average time needed to get HHHHH starting fresh, the average of 1 + X and 1 is 32,” Winkler writes. “Solving for X yields a startlingly high 62 flips.” To get your expected dues down to $32, you need to pick a sequence where this “head start” effect doesn’t obtain. There are 10 such sequences; one is HHHTT.

(Peter Winkler, “Coin Flipping,” Communications of the ACM 56:11 [November 2013], 120.)


An observation by Oxford University mathematician Nick Trefethen:

A student leaves university in America with a transcript full of information. Even with grade inflation, there are thirty marks of A or A- or B+ or B to look at, each one attached to a different course like Advanced Calculus or 20th Century Philosophy or Introduction to Economics. Grade-point averages are constructed from these transcripts and reported to three digits of accuracy.

An Oxford graduate finishes with no transcript, just a degree result which may be a First, a II.1, a II.2, a Third, a Pass, or a Fail. Failures are more or less nonexistent, and the numbers last year [2000] for the other degrees were 691, 1925, 374, 39, and 3, respectively. The corresponding probabilities are 23%, 63%, 12%, 1%, and 0.1%.

If you add up these probabilities times their base 2 logarithms, all times minus one, you find out how much information there is in an Oxford degree. The result is: 1.37 bits of information.

(From Trefethen’s Index Cards, 2011.)

A Confusing Census

There are 12 people in a room. Some always tell the truth, and the rest always lie.

#1 says, “None of us is honest.”
#2 says, “There is not more than 1 honest person here.”
#3 says, “There are not more than 2 honest people here.”
#4 says, “There are not more than 3 honest people here.”
#5 says, “There are not more than 4 honest people here.”
#6 says, “There are not more than 5 honest people here.”
#7 says, “There are not more than 6 honest people here.”
#8 says, “There are not more than 7 honest people here.”
#9 says, “There are not more than 8 honest people here.”
#10 says, “There are not more than 9 honest people here.”
#11 says, “There are not more than 10 honest people here.”
#12 says, “There are not more than 11 honest people here.”

How many honest people are in the room?

Click for Answer

You Are There

Prague artist Robert Barta’s installation Crossing Half a Million Stars consists of 500,000 ball bearings covering the floor of a room.

The visitors themselves create a spontaneous performance as they try to make their way across it.

“Pussy and the Mouse”

A puzzle by Henry Dudeney:

‘There’s a mouse in one of these barrels,’ said the dog.

‘Which barrel?’ asked the cat.

‘Why, the five-hundredth barrel.’

‘What do you mean by the five-hundredth? There are only five barrels in all.’

‘It’s the five-hundredth if you count backwards and forwards in this way.’

And the dog explained that you count like this:

1     2     3     4     5
9     8     7     6
     10    11    12    13

So that the seventh barrel would be the one marked 3 and the twelfth barrel the one numbered 4.

‘That will take some time,’ said the cat, and she began a laborious count. Several times she made a slip, and had to begin again.

‘Rats!’ exclaimed the dog. ‘Hurry up or you will be too late!’

‘Confound you! You’ve put me out again, and I must make a fresh start.’

Meanwhile the mouse, overhearing the conversation, was working madly at enlarging a hole, and just succeeded in escaping as the cat leapt into the correct barrel.

‘I knew you would lose it,’ said the dog. ‘Your education has been sadly neglected. A certain amount of arithmetic is necessary to every cat, as it is to every dog. Bless me! Even some snakes are adders!’

Now, which was the five-hundredth barrel? Can you find a quick way of arriving at the answer without making the actual count?

Click for Answer

Oh Well

In 1913 Canadian politician Sam Hughes proposed the MacAdam Shield Shovel, a spade that could double as a protective shield in the trenches — it was provided with a hole through which a soldier could survey the enemy.

Some 20,000 had been manufactured before it was discovered that the blade was not remotely bulletproof, and it wasn’t much use as a shovel … because there was a hole in it.