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Page:Popular Science Monthly Volume 23.djvu/508

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THE POPULAR SCIENCE MONTHLY.

if the piano is touched, the color appears over the keys. The seat of color, he says, "appears to me to be principally where the sound is made above the person who is singing. The impression is the same if I do not see any one. There is no sensation in the eye, for I think of the same color with my eyes shut. It is the same when the sound comes from the street through walls and partitions. When I hear a choir of several voices, a host of colors seem to shine like little points over the choristers; I do not see them, but I am impelled to look toward them, and sometimes while looking toward them I am surprised not to see them."

These phenomena are strange; possibly the description of them may lead to the discovery of other equally singular examples, and it will become feasible to group them and look for an interpretation of them. It is now a question whether they are hallucinations, like the well-known ones of hearing voices and seeing phantoms, or whether they result from accidental confusion of the auditory and visual nervous fibers. As we now know that there are motor nerve-centers, specially adapted to particular functions, there may be also chromatic centers near the acoustic centers, and these different centers may echo to each other; and the acoustic fibers may cause synchronous vibrations at definite periods of the chromatic fibers. Without multiplying hypotheses, we have pointed out the facts, and must be satisfied to wait for the explanation of them till it is possible to make it.—Le Monde de la Science et de l'Industrie.

 

THE FORMATION OF SEA-WAVES.
By ÉMILE SOREL.

ONE of the first things to be observed in a storm is the way the wind acts. It does not blow regularly, but in gusts. At one moment it bends over the branches of the trees; in the next, it has loosened its hold, and let them fly back. We see it swelling out a ship's sails into a full puff; a minute later the sails hang flapping as if they had been struck down.

We can account for these phenomena and explain the intermittence of the wind-puffs by assuming that the molecules of air, displacing each other, excite a vibratory movement, which gives rise to little undulations following one after another at intervals of a few seconds. The resultant of a series of these undulations is a puff of wind which comes on suddenly and is followed by a short lull. A series of puffs constitutes a squall, and an aggregation of squalls forms the atmospheric wave which is called a gale of wind. We should naturally expect to observe the same phases in the formation of sea-waves; and,