Spring Showers
This is clever — in 1893 Texas inventor Martin Everhart patented a clock-winding mechanism that’s driven by rainwater. The water fills a tank in the attic and then drops through a pipe into a pail in the clock. The pail is balanced with a counterweight, so it falls and rises continuously, accepting a new measure of water at the top and discharging it at the bottom. This motion winds the clock.
I guess the whole thing would stop eventually in a drought, but the clock can be wound by hand if necessary.
Podcast Episode 101: Jerome
In 1863 the residents of Sandy Cove, Nova Scotia, discovered a legless man on the shore of St. Mary’s Bay. He spoke no English and could not tell them who he was or where he had come from. In this week’s episode of the Futility Closet podcast we’ll tell the story of “Jerome” and what is known or guessed of his past.
We’ll also learn about explosive rats in World War II and puzzle over a computer that works better when its users sit.
Poem Codes
During World War II the British Special Operations Executive used poetry to communicate with its agents in enemy territory. The sender and receiver would agree in advance on a poem, and by numbering its letters they produced a simple cipher that could be used to transmit messages. Because both sides could memorize the poem, there was no codebook to lose, but the Nazis could break the code fairly easily, particularly if the poem was well known.
Realizing this, SOE codes officer Leo Marks began to introduce original poems of his own creation. He gave this one to French agent Violette Szabo in March 1944:
The life that I have is all that I have,
And the life that I have is yours.
The love that I have of the life that I have
Is yours and yours and yours.
A sleep I shall have, a rest I shall have,
Yet death will be but a pause.
For the peace of my years in the long green grass
Will be yours and yours and yours.
Marks had written it three months earlier in memory of his girlfriend Ruth, who had died in a plane crash in Canada. The poem became famous when it was read in the 1958 film Carve Her Name With Pride, about Szabo’s exploits in the war. Unfortunately, Szabo herself was captured, tortured, and killed before she could transmit any messages.
Moving Constants
If you mark two points on a circle, A and B, and a third point T, then angle ATB remains constant as T moves along the segment between A and B. (If you mark a point S in the circle’s other segment then you get another constant angle, ASB, and ASB = 180 – ATB.)
If two circles intersect at A and B and we move T as before along the segment opposite the second circle, and we extend TA and TB to P and Q on the second circle, then the length of chord PQ remains constant as T moves.
(From David Wells, The Penguin Dictionary of Curious and Interesting Geometry, 1992.)
Last Orders
About noon, when Major Pendleton came into the room, he asked, ‘Who is preaching at headquarters today?’ He was told that Mr. Lacy was, and that the whole army was praying for him. ‘Thank God,’ he said; ‘they are very kind to me.’ Already his strength was fast ebbing, and although his face brightened when his baby was brought to him, his mind had begun to wander. Now he was on the battle-field, giving orders to his men; now at home in Lexington; now at prayers in the camp. Occasionally his senses came back to him, and about half-past one he was told that he had but two hours to live. Again he answered, feebly but firmly, ‘Very good; it is all right.’ These were almost his last coherent words. For some time he lay unconscious, and then suddenly he cried out: ‘Order A.P. Hill to prepare for action! Pass the infantry to the front! Tell Major Hawks –‘ then stopped, leaving the sentence unfinished. Once more he was silent; but a little while after he said very quietly and clearly, ‘Let us cross over the river, and rest under the shade of the trees,’ and the soul of the great captain passed into the peace of God.
— George Francis Robert Henderson, Stonewall Jackson and the American Civil War, 1903
In a Word
videnda
n. things worth seeing
Condolence
A letter from Abraham Lincoln to Fanny McCullough of Bloomington, Ill., whose father had died leading a charge in Mississippi, Dec. 23, 1862:
Dear Fanny: It is with deep regret that I learn of the death of your brave and kind father, and especially that it is affecting your young heart beyond what is common in such cases. In this sad world of ours sorrow comes to all, and to the young it comes with bitterer agony because it takes them unawares. The older have learned ever to expect it. I am anxious to afford some alleviation of your present distress. Perfect relief is not possible, except with time. You cannot now realize that you will ever feel better. Is not this so? And yet it is a mistake. You are sure to be happy again. To know this, which is certainly true, will make you some less miserable now. I have had experience enough to know what I say, and you need only to believe it to feel better at once. The memory of your dear father, instead of an agony, will yet be a sad, sweet feeling in your heart of a purer and holier sort than you have known before.
Please present my kind regards to your afflicted mother.
Your sincere friend,
A. Lincoln
The Barbershop Paradox
In 1894 Lewis Carroll published a conundrum that, he wrote, presents “a very real difficulty in the Theory of Hypotheticals.” Suppose that Allen, Brown, and Carr run a shop. At least one of them must always be present to mind the shop, and whenever Allen leaves he always takes Brown with him. Now, suppose that Carr is out. In that case then if Allen is out then Brown must be in, in order to tend the shop. But we know that this isn’t true — we’ve been told that whenever Allen is out then Brown is out.
Since the supposition that Carr is out leads to a falsehood, then it must itself be false. Confusingly, the laws of logic seem to require that Carr never leave the shop.
“I greatly hope that some of the readers of Mind who take an interest in logic will assist in clearing up these curious difficulties,” Carroll wrote. Modern logicians would say that this is a simple error in reasoning, rather than a logical disaster. But what is the error?
Unquote
“What I cannot create, I do not understand.” — On Richard Feynman’s Caltech blackboard at the time of his death in 1988