Licence: Public Domain Mark
Credit: L'inconnu = The unknown / By Camille Flammarion. Source: Wellcome Collection.
Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.
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![20 degrees 1,047, ,576 ) -, , ,433 [^'^^ 25 33,554, 30 1,073,741,824 Electricity. 35 34,359,738,368^ 40 1,099,511,627,776 >■ Unknown. 45 35,184,372,088,832) 48 281,474,976,716,656) 49 562,949,953,421,312 V-Light.» 50 1,125,890,906,842,624) 55 36,028,797,018,963,268^ 56 72,057,594,037,927,936 I Unknown. 57 144,115,188,075,855,872) 58 '' 288,230,376,151,711,744 ] 59 576,460,752,303,423,488 I 60 1,152,921.504,606,846,976 r-^-^^^^- 61 5,305,843,009,213,693,952 J 62 4,611,686,018,427,389,904 ) 63 9,223,372,636,854,775,808 [ Unknown. At the fifth degree, after the beginning to 52 vibrations in a second, we enter the region where the vibration of the atmosphere is revealed to us under the name of sound. We there find the lowest musical note. If among musical notes the most solemn is chosen—for instance, the lowest octave of the organ—it will be perceived that elementary sensations, though forming a continuous whole, which is essential that the sound may remain musical, are nevertheless distinct to a certain degree. The lower the note is, says Helmholtz, the better does the ear distinguish in it the successive pul- sations of the air. In the six following degrees the vibrations in each second increase from 32 to 52,768; each doubling reproduces the same note in a higher octave. The normal diapason, which gives us the note la (or F), is a vibration of 455 a second, and has 870 vibrations when doubled. The sharpest sound has about 56,000 vibrations, and the region of sound ends there, so far as the human ear is concerned. But probably some animals, better gifted than ourselves, may hear sounds too ' Luminous rays, caloric and chemical, spectra of the infra-red to the ultra-violet.](https://iiif.wellcomecollection.org/image/b21052177_0036.jp2/full/800%2C/0/default.jpg)
