. Machinery and processes of the industrial arts, and apparatus of the exact sciences. ; whereas, if the fifth were seven-twelfths of the octave, as in equaltemperament it would be, twelve-fifths should be precisely equal toseven octaves. If the exact difference between the major and minortones, viz., f i, be taken as the value of the comma, the value of twelve-fifths will be , and that of seven octaves ; the differencebeing , or about a comma and a tenth. Of all this subject, which is so little understood by most persons whomake use of musical instruments, Prof. Tillmans Tonom
. Machinery and processes of the industrial arts, and apparatus of the exact sciences. ; whereas, if the fifth were seven-twelfths of the octave, as in equaltemperament it would be, twelve-fifths should be precisely equal toseven octaves. If the exact difference between the major and minortones, viz., f i, be taken as the value of the comma, the value of twelve-fifths will be , and that of seven octaves ; the differencebeing , or about a comma and a tenth. Of all this subject, which is so little understood by most persons whomake use of musical instruments, Prof. Tillmans Tonometer furnishesa simple elucidation, which, by directly addressing itself to the eye, con-veys the truths to be illustrated more directly and more clearly than 476 PARIS UNIVERSAL EXPOSITION. pages of numerical statements can do. A circle represents the octave,(the septate Prof. Tillman calls it, taking the name from the number ofintervals rather than from the number of notes required to produce them.)This is divided into twelve equal semitones, or grades, as he names them, Fig. Tillmans Tonometer Dial. each containing five artificial commas, making sixty in all. Seven whiteescutcheons mark the places of the notes of the natural diatonic scale;and five black escutcheons indicate the interpolated semitones. Twocircular musical staves connecting these escutcheons show the places ofthe several notes as written in the tenor and in the bass. The C, as thetonic note of the natural scale, takes its place at the top of the other letters follow in their order. But while the system of equaltemperament is shown by the twelve visible grades, the proper places ofthe notes of the chromatic scales are shown on the circular division withproper marks. This is the fixed part of the apparatus. Within the circle just described is a movable circle revolving on thecommon center, and carrying seven conspicuous arms, each terminated
Size: 1565px × 1596px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubjectmachinery, booksubjectscientificappa
