AMERICAN INSTITUTE. 499 



the next note, called a diatonic semitone, is an interval exceeding one-half 

 of even the major tone. 



This unequal division of the scale compels us to vary the intervals from 

 their true position whenever keyed instruments are used, having twelve 

 semitones in the octave. To this class belong the piano, organ, flute, etc. 

 On the violin and other stringed instruments, except the guitar, the player 

 can slide the finger so as'to produce the true note. So, on the trombone, 

 the pipes, by sliding into each other, can be made to give the true sound. 

 On these instruments C sharp and D flat are two distinct notes; but on 

 the organ, piano, flute, and other keyed instruments, these two notes must 

 be represented by the same sound. This is accomplished by what is called 

 tempering ; in which process the fifths are slightly diminished in pitch and 

 the fourths slightly increased; by this means a system is introduced which 

 nearly approximates to the true intervals in the keys of one, two, and 

 three sharps, or the same number of flats ; but is less correct as the number 

 of flats or sharps is increased. Another system of temperament is the isotonic f 

 in \vhich the semi-tone intervals are equi-distant. Of course, in this ar- 

 rangement one key is no better than another, and all are too far from the 

 true diatonic scale to be agreeable. The ear leads the voice to sing cor- 

 rectly in every key ; and to make the best harmony, nothing but stringed 

 instruments and sliding trumpets should be used. 



It is the height of the vocal art to sing correctly, and yet to temper the 

 voice to tempered instruments whenever occasion requires. The voice 

 should first be trained to true intonation because the ear, accustomed to 

 true measurements, can easily guide the voice through the mazes of tem- 

 pered harmony. It is of the highest importance to have a clear view of 

 the science of acoustics before attempting the art of musical vocalization or 

 instrumentation. For the guide of vocalists and instrumental performers, 

 the speaker has invented an instrument which he calls the Tonometer 5 

 its object being to measure to the, eye all possible intervals, in the major 

 and minor modes, and is adapted both to the tempered and true systems, 

 so that more than fifty different tonics may be assumed in a single octave. 

 By this instrument, thorough bass, an almost incomprehensible study to 

 ordinary musicians, becomes easy of aequitition. He would take an early 

 opportunity of presenting it to the Association for their inspection. 



The Association adjourned, having selected two subjects, viz: "Life 

 Boats," a paper by Mr. Garbanati ; "Aerial Navigation," by Mr. Stewart. 



Polytechnic Association of the American Institute, ) 



November 30, 1859. \ 



Mr. Fisher, Chairman, pro tem. Mr. Garvey, Secretary, pro tcm. 



The regular subjects of the evening. 



"lite boats" and "aerial navigation." 



Mr. Garbanati introduced his paper by remarking that he had read 

 through the proceedings of the Institute for three or four years, and never 

 once found anything discussed in connection with the sea or navigation. 



