492 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 nerv- 

 ous fibers. As we now know that there are motor nerve-centers, spe- 

 cially 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 vibra- 

 tions 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 V Industrie. 







THE FOKMATION OF SEA-WAYES. 



By EMILE 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 sAvelling 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 intermit- 

 tence of the wind-puffs by assuming that the molecules of air, displac- 

 ing 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 atmos- 

 pheric wave which is called a gale of wind. We should naturally 

 expect to observe the same phases in the formation of sea-waves ; and, 



