A puzzle by Mel Stover:
Move the minus sign to make an expression equivalent to nine fifty.
(If you sense a trick, you’re right.)
A puzzle by Mel Stover:
Move the minus sign to make an expression equivalent to nine fifty.
(If you sense a trick, you’re right.)
Literary scholar Robert Hauptman calls this “marginal emendation run amok” — it’s a page from Henry James’ 1877 novel The American as James revised it anxiously for a new edition in 1907. He had decided the plot was unconvincing and asked for so many changes that two copies of the book had to be inlaid page by page on larger sheets to give him room to mark all the revisions.
On the last page, above, “James has partially or fully crossed out 16 of the 19 lines and rewritten the text for the definitive New York edition in the margins and at the foot of the page,” notes Hauptman. “His scrawling alterations cover virtually all of the generous white space and must be inserted in at least three different locations in the original text. Words are blotted out or struck in the new version, and as he approaches the bottom of the page, the lettering diminishes in size, because he realizes that he will run out of room.”
“The work on the earlier novels has involved much labour — to the best effect for the vile things, I’m convinced,” James had written to Grace Norton that March. Modern critics generally disagree — most editions today use the original version.
(From Robert Hauptman, Documentation, 2008, and Harvard’s Marks in Books, 1985.)
By Éric Angelini. A regular chess game reached this position after Black’s fifth move. Four pieces have moved. Which ones?
This is interesting — in order for a simple arch to stand, its shape when inverted must fit into the limits described by a hanging chain (a catenary).
Spanish Catalan architect Antoni Gaudí followed this principle in designing some of his buildings — he created inverted models and let the shapes of hanging chains or weighted strings determine the shapes of the arches.
In the early 1940s a curious question began to circulate among the members of the Princeton physics department. An ordinary lawn sprinkler like the one shown here would turn clockwise (in the direction of the long arrow) as its jets ejected water (short arrows). If you reversed this — that is, if you submerged the sprinkler in a tank of water and induced the jets to suck in the fluid — would the sprinkler turn in the opposite direction?
The problem is associated with Richard Feynman, who was a grad student at the time (and who destroyed a glass container in the university’s cyclotron laboratory trying to find the answer).
In fact Ernst Mach had first asked the question in an 1883 textbook. The answer, briefly, is no: The submerged sprinkler doesn’t turn counterclockwise because counterbalancing forces at the back of the nozzle result in no net torque. Experiments tend to bear this out, although in some cases the sprinkler turns slightly counterclockwise, perhaps due to the formation of a vortex within the sprinkler body.
During a visit to a club in 1775, Samuel Johnson was observed to put several Seville oranges into his pocket after squeezing their juice into a drink he’d made for himself. The friends who saw this “seemed to think that he had a strange unwillingness to be discovered.” Visiting Johnson the next morning and seeing the orange peels scraped and cut into pieces on a table, James Boswell asked about them:
JOHNSON. ‘I have a great love for them.’
BOSWELL. ‘And pray, Sir, what do you do with them? You scrape them it seems, very neatly, and what next?’
JOHNSON. ‘Let them dry, Sir.’
BOSWELL. ‘And what next?’
JOHNSON. ‘Nay, Sir, you shall know their fate no further.’
BOSWELL. ‘Then the world must be left in the dark. It must be said (assuming a mock solemnity) he scraped them, and let them dry, but what he did with them next he never could be prevailed upon to tell.’
JOHNSON. ‘Nay, Sir, you should say it more emphatically:–he could not be prevailed upon, even by his dearest friends, to tell.’
I don’t think this has ever been fully explained, but Boswell notes that, in a letter to Mrs. Piozzi, Johnson had once recommended “‘dried orange-peel, finely powdered,’ as a medicine.”
A thought-provoking piece of nonsense by Russian absurdist poet Daniil Kharms:
Philosopher!
Part of New York is standing still. In 1978, artist Alan Sonfist reclaimed a rubble-strewn lot on the corner of West Houston Street and La Guardia Place in Greenwich Village and re-established the vegetation, soil and rock formations that had existed there before the Western settlers arrived.
“As in war monuments that record the life and death of soldiers, the life and death of natural phenomena such as rivers, springs and natural outcroppings need to be remembered,” he wrote in a 1968 manifesto proposing the project. Interestingly, he’d hoped to do even more than this: “On Canal Street I propose to create a marshland and a stream; on Spring Street I propose to restore the natural spring; in front of City Hall I propose to restore the historical lake. There are a series of fifty proposals I have made for the City of New York.”
Only this one, called Time Landscape, has been realized. But it’s still growing after 44 years, a tiny piece of history that Sonfist says helps the city remember its heritage.
I don’t know whether this is contrived or whether a student offered it on an actual exam — Ed Barbeau presented “this little beauty of a howler” in the January 2002 College Mathematics Journal, citing Ross Honsberger of the University of Waterloo in Ontario.
In his Harmonices Mundi of 1619, Johannes Kepler wrote, “The heavenly motions are nothing but a continuous song for several voices, to be perceived by the intellect, not by the ear; a music which, through discordant tensions, through syncopations and cadenzas as it were, progresses toward certain pre-designed six-voiced cadences, and thereby sets landmarks in the immeasurable flow of time.” In 1979 Yale geologist John Rodgers and musician Willie Ruff scaled up the frequencies of the planetary orbits into the range of human hearing so that Kepler’s “harmony of the world” could become audible:
Mercury, as the innermost planet, is the fastest and the highest pitched. It has a very eccentric orbit (as planets go), which it traverses in 88 days; its song is therefore a fast whistle, going from the E above the piano (e′′′′′) down more than an octave to about C# (c#′′′′) and back, in a little over a second. Venus and Earth, in contrast, have nearly circular orbits. Venus’s range is only about a quarter tone, near the E next above the treble staff (e′′′); Earth’s is about a half tone, from G (g′′) to G# at the top of that staff. … Next out from Earth is Mars, again with an eccentric orbit … it ranges from the C above middle C (c′′) down to about F# (f#′) and back, in nearly 10 seconds. The distance from Mars to Jupiter is much greater than that between the inner planets … and Jupiter’s song is much deeper, in the baritone or bass, and much slower. It covers a minor third, from D to B (D to B1) just below the bass staff. Still farther out and still lower is Saturn, only a little more than a deep growl, in which a good ear can sometimes hear the individual vibrations. Its range is a major third, from B to G (B2 to G2), the B at the top being just an octave below the B at the bottom of Jupiter’s range. Thus the two planets together define a major triad, and it may well have been this concord … that made Kepler certain he had cracked the code and discovered the secret of the celestial harmony.
(The outer planets, discovered after Kepler’s time, are represented here with rhythmic beats.) “The Earth sings Mi, Fa, Mi,” Kepler wrote. “You may infer even from the syllables that in this our home misery and famine hold sway.”
(John Rodgers and Willie Ruff, “Kepler’s Harmony of the World: A Realization for the Ear,” American Scientist 67:3 [May-June 1979], 286-292.)