Edward O’Brien patented this “body-attached rearview mirror” in 1905 “to facilitate the dressing of the hair and the inspection of the back of the head and head dress.” Essentially it’s a harness that bears three mirrors and an illuminating bulb, replacing a bothersome hand mirror.

“By this means, both hands of the wearer are free to properly arrange the head dress, brush the hair and the like, without disturbing the adjustment of the mirror and illuminating means.”

Just remember to take it off afterward …


The lion tamers wrestle with the lions in a cage,
With but a fragile whip they dare their charges’ feral rage.
They put their heads in tigers’ mouths and do not flinch a grain,
But … they never tried to take a cat five hundred miles to Maine.

You hunters who bring back alive from Afric’s roaring shore
The nilghai and the elephant, the rhino and the boar;
Who load them on a steamer and evince no sign of strain –
Let’s see you drive a cat five hundred miles to Maine.

Go cope with your rhinoceros bare-handed and alone,
Or kick a famished grizzly if for harmless fun you hone,
Or aggravate a timber wolf with pokings of a cane,
But do NOT try to drive a cat five hundred mile to Maine.

There is no word, there is no tongue, there is no ink to tell
One tenth of what one cat can raise of concentrated hell,
When after two hours’ driving to mistaken qualms you yield
And take poor puss to stretch her limbs in some adjacent field.

And if you’ve done the things set forth in stanzas two and three,
You stand a chance, when Krazy from the leash has wriggled free
(Provided you are clad in steel with hat and gloves to match),
To get her back into the car without a bite or scratch.

Ye lion tamers, naturalists, and big-game hunters eke,
When I’m around be chary of your tendency to speak.
To hear you boast your petty deeds gives me a shooting pain
For I have driven Krazy — phew! — five hundred miles to Maine!

– Baron Ireland

Two Lists

Write out the positive powers of 10 in both base 2 and base 5:

powers of 10

Now for any integer n > 1, we’ll find exactly one number of length n somewhere on the two lists. They contain one 3-digit number, one 4-digit number, and so on forever — if n = 100 we find a 100-digit number in the 30th position on the base 2 list.

(This result first appeared in the 1994 Asian Pacific Mathematics Olympiad. I found it in Ravi Vakil’s A Mathematical Mosaic.)

Two further curious lists: If we write out the triangular numbers, those in positions 3, 33, etc. show a pattern:

T(3) = 6
T(33) = 561
T(333) = 55611
T(3,333) = 5556111
T(33,333) = 555561111
T(333,333) = 55555611111


T(6) = 21
T(66) = 2211
T(666) = 222111
T(6,666) = 22221111
T(66,666) = 2222211111
T(666,666) = 222222111111

(Thanks, Larry.)


The tombstone of Constanze Mozart’s second husband calls him “the husband of Mozart’s widow.”

Things to Come,_Feb_9,_1864.jpg

In May 1861, barely three weeks after the start of the Civil War, Mary Todd Lincoln received a letter from Helen Rauschnabel of Rochester, N.Y., relating “a remarkable dream I had last night about Mr. Lincoln which I think has a significant meaning.”

I dreamed it stormed & thunderd & lightned terribly, it seemed as tho the Heavens & Earth were coming together, but it soon ceased, still there seemed to be very dark clouds sailing thro the horison, I thought I stood pensively viewing the scene, when a man resembling Mr Lincoln appeard standing erect in the firmament with a book in his hand, he stood as near as I could calculate over the City of Washington, his head seemed reard above the lightnings flash and thunder bolt, the sun seemed to be just rising in the East, and its rays shed a soft mellow light around about him, beneath his feet rolled dark & heavy clouds which the sun light was fast dispeling, I saw him walk thro all the Southern part of the horison with a book in one hand, & a pen in the other.

“When he got to the western part of the firmament he made a halt & stood erect,” she remembered. “He was crowned with honors & coverd with Laurels, and looked very smiling.” She found herself singing a verse, which she remembered when she awoke and committed to paper: “A voice from the North has proclaimed the glad Morn / And Slavery is ended & Freedom is born / The fair Sunny South is restor’d one more / Secession is ended & Slavery is ore.”

Some “Odd” Theorems

Draw any triangle and divide each leg into three equal segments. Connect each vertex to one of the trisection points on the opposite leg, as shown, and the triangle formed in the center will have 1/7 the area of the original triangle.

2/5 semicircle theorem

A square inscribed in a semicircle has 2/5 the area of a square inscribed in a circle of the same radius.

1/5 square theorem

Draw a square and connect each vertex to the midpoint of an opposite side, as shown. The square formed in the center will have 1/5 the area of the original square.

A “proof without words”:

1/5 square theorem - proof


“People who count their chickens before they are hatched act very wisely because chickens run about so absurdly that it’s impossible to count them accurately.” — Oscar Wilde

Ice Water

A boat floats in a swimming pool. In the boat is a block of ice. If the block is dumped into the water and melts, does the water level rise or fall?

Click for Answer

Haunting Attire

Why do ghosts wear clothes? If a ghost is the spirit of a living creature, how can it carry its inanimate garments into the afterlife?

“How do you account for the ghosts’ clothes — are they ghosts, too?” asked the Saturday Review in 1856. “What an idea, indeed! All the socks that never came home from the wash, all the boots and shoes which we left behind us worn out at watering-places, all the old hats which we gave to crossing-sweepers … What a notion of heaven — an illimitable old clothes-shop, peopled by bores, and not a little infested with knaves!”

In 1906 psychic researcher Andrew Lang argued that, far from confusing the notion of an afterlife, ghosts’ clothing might even help to corroborate its existence. “A pretty instance occurs, I think, in a biography of Warren Hastings. The anecdote, as I remember it, avers that at a meeting of the Council of the East India Company in Calcutta one of the members (I think several shared the experience) saw his own father, wearing a hat of a peculiar shape, hitherto strange to the observers. In due time came a ship from London bearing news of the father’s death, and a large and well-selected assortment of the new hat fashionable in England. It was the hat worn by the paternal appearance! If the circumstances are recorded in the minutes of the proceedings of the Council, which I have not consulted, then the hat of that spook becomes important as evidence.”

Even if we grant that a dead person can convey his most personal belongings into the afterlife, how are we to account for phantom ships, coaches, and railway trains? In his 1879 book The Spirit World, American spiritualist Eugene Crowell decided that, rather than being the spirits of “dead” earthly conveyances, these are constructed in the afterlife by the ghosts of mariners and railwaymen who want to ply their trades again. Spectral ships “glide over the waves without sinking,” Crowell explained, “and earthly winds propel them at rates of speed which our ships cannot attain.” If that’s true, then perhaps some ghostly tailor is simply manufacturing clothes for the naked spirits of the newly dead. Decent of him.

The Broken Deck

When eight certain cards are removed from a standard poker deck, it becomes impossible to deal a straight flush. What are the cards? (Assume the deck contains no jokers.)

Click for Answer
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