434 Mr. Tomlinsons Experiments and [June 



spared myself the trouble, and what to me was of most con- 

 sequence, the time of testing each glass separately. This 

 method also is superior to that depending on a musical ear, 

 however good it may be. Thus, I completed two octaves, 

 together with four of the most useful semi-tones, and 

 arranged them in a deal case according to Dr. Arnott's 

 method, which is a very convenient one. My instrument 

 allows me to play upwards of fifty popular tunes and 

 national airs in the key of B flat major; and, in point of 

 tone it surpasses those sold by the makers, who charge from 

 twelve to fifteen guineas for two octaves, while mine has 

 cost me but twenty-five shillings. 



48. Dr. Franklin, I believe, contrived the first instrument 

 and suggested the method of tuning the glasses by means 

 of water. But this mode is objectionable for several reasons. 

 The effect of water is to lessen the number of vibrations, 

 and thus to lower the fundamental note of the glass. By 

 this means, not only is the natural richness of the note 

 impaired, but the relative accuracy of the notes can.rarely 

 be obtained. In warm weather I have known an instru- 

 ment get out of tune in a few hours simply by the evapora- 

 tion of the water. A patent was, I think, taken out some 

 years ago to remedy this defect. The patentee dispensed 

 altogether with water, and coated the belly of the glass 

 with a cement which dried and hardened, and thus brought 

 the note down to the desired pitch. This mode, it will be 

 seen, is objectionable, as the tone is much deteriorated, and 

 should any of the cement chip off, which it is not unlikely 

 to do in using or cleaning, the note becomes immediately 

 wrong. Another method is to grind the glasses to the proper 

 pitch, this, however, is both tedious and expensive, and, 

 therefore, objectionable. 



49. By the plan that I propose, (47.) all these objections 

 are obviated, and a beautiful instrument is obtained, pos- 

 sessing the great advantage, so well appreciated by the 

 musical amateur, of being always in tune. It will, how- 

 ever sometimes happen that a glass may be met with yield- 

 ing a full sympathetic note, yet when vibrated by the finger 

 the interference of sound (12.) arising from irregularities 

 unappreciable to the eye, will be sufficient to exclude it 

 from the set, but this objection is easily obviated, by having 

 recourse to another glass. 



