The second movement of Bruckner’s seventh symphony climaxes in a famous cymbal crash; legend has it that Bruckner added the symbolic note on hearing of Wagner’s death.

This is the only cymbal note in the whole symphony, so the player has plenty of time to worry about it.

“This note becomes the occasion of indescribable anguish to almost every cymbal player responsible for its delivery,” noted Jens Rossel of Denmark’s Århus Symphony. “It must come at precisely the right instant, or it simply ruins everything. A few minutes before, you always see the fellow begin to turn in his chair, start to rub his hands and wipe his palms on his trousers. When he stands up he plants his feet, just so, like a baseball catcher bracing himself for a fast pitch. The moment comes and the cymbals crash. It’s a matter of just a few milliseconds, but what it represents to the music is either life or death.”

But maybe that’s the essence of the job. Someone once asked Sir Malcolm Sargent, “What do you have to know to play the cymbals?” He said, “Nothing — just when.”

(Frank R. Wilson, “Music and the Neurology of Time,” Music Educators Journal 77:5, January 1991.)

Some of your old books may contain hidden artworks: Beginning in the 17th century, a book’s binder would sometimes paint a watercolor scene on the edge of the book’s page stack. If the pages were then gilded, the image might remain hidden for years until the pages were fanned.

Sometimes two different images are hidden in the same book, revealed successively when the pages are fanned “up” and “down.” In rare cases paintings are hidden not just on the book’s fore edge but on the top and bottom as well, offering a panoramic view of the painting’s subject.

John Cage’s 4’33” is commonly described as “four and a half minutes of silence,” but in fact it’s the opposite — Cage hoped to lead the audience to hear the ambient sounds of the concert hall as music, to accept as art sounds that they wouldn’t normally consider in that way.

“What they thought was silence, because they didn’t know how to listen, was full of accidental sounds,” he said of the piece’s 1952 premiere. “You could hear the wind stirring outside during the first movement. During the second, raindrops began pattering on the roof, and during the third the people themselves made all kinds of interesting sounds as they talked or walked out.”

In a broad sense 4’33” was Cage’s most significant work, but the notion of a dedicated piece of art with no substance does introduce some perplexing puzzles. The work debuted as a piano piece with a specified length, but Cage later said that “the work may be performed by any instrumentalist or combination of instrumentalists and last any length of time,” and indeed he produced varying scores in different notations. Can all of these be said to be the same piece?

The “In Futurum” movement for solo piano from Czech composer Erwin Schulhoff’s 1919 Fünf Pittoresken consists entirely of rests, but directs the performer to play “the entire song with as much expression and feeling as you like, always, right to the end!” (French pianist Philippe Bianconi wondered, “Should I just sit there?”) And Alphonse Allais’s 1897 Funeral March for the Obsequies of a Deaf Man, below, consists of 24 blank measures. Could an unwitting audience member distinguish either of these from Cage’s work?

A puzzle by philosopher Patricia Werhane of Loyola University of Chicago: Suppose that a pianist were engaged to perform 4’33” but had to withdraw at the last moment, and in desperation the stage manager sat in his place. Would this be a performance of Cage’s work? Would it be a musical performance?

Now more than 60 years old, Cage’s idea may still be too novel for a wide public. When BBC Radio 3 broadcast the first U.K. orchestral performance of 4’33” in 2004, the network had to turn off an emergency backup system that would have interpreted the silence as dead air — and begun playing music.

Swiss artist Markus Raetz created this innovative portrait of Piero della Francesca. Two mobiles are fitted with aluminum plates that are juxtaposed successively as the mobiles rotate. Piero appears between them.

Raetz’s kinetic sculpture of Kiki de Montparnasse, below, uses a similar idea:

No other painter’s works have been forged as frequently as Corot’s. One day a gentleman shows up in the master’s studio, who, having bought a painting signed ‘Corot’ in a small art shop, wants to know whether it has really been painted by Corot. After one brief look at the canvas Corot shakes his head. Transported by rage, the buyer declares that he will report the art dealer to the police. ‘Report to the police?,’ the painter vents his annoyance. ‘Nonsense, that man has a wife and a child. Do you want to ruin the life of that fellow?’ ‘What do I care about wife and child? A fraud is a fraud and the law ….’ ‘The law? Bah, it won’t take much to turn this little painting into an original Corot.’ With that, the master puts the canvas on the easel and adds a few brush strokes, thus turning the fake Corot into a genuine one. ‘There,’ he murmurs in a satisfied voice, returning the painting to the buyer, ‘now you won’t be able to say anymore that this is forgery and fraud. You could see it with your own eyes how I painted it.’

— Alfred Georg Hartmann, Das Künstlerwäldchen. Maler-, Bildhauer- und Architekten-Anekdoten, 1917, quoted in Sándor Radnóti, The Fake: Forgery and Its Place in Art, 1999

Suppose the Grand Canyon were man-made. It could have been formed (though it wasn’t) by agricultural or industrial erosion; the results of poor farming methods can look very similar — artificial badlands — if on a smaller scale. Would this hideous scar on the fair face of the earth still be a national park? Would anyone visit it other than groups of awed schoolchildren studying Environmental Destruction, absorbing the dreadful lesson of what can happen to a desert raped by human exploiters? Strip mining can produce spectacular and dramatic landscapes. W.H. Auden loved the lead-mining landscapes of Cornwall above all others; the evocative and aromatic hillsides of the Mediterranean, with their olives, sages, thyme, and dwarf conifers, are a result of centuries of deforestation, goat herding, and the building of roads and cities.

— Frederick Turner, “Cultivating the American Garden: Toward a Secular View of Nature,” Harper’s, August 1985