Giuseppe Tartini - Lettere e documenti / Pisma in dokumenti / Letters and Documents - Volume / Knjiga / Volume II

370 remember the news of the experiment that took place in June; as, if you remembered it, you would not have written, as is written above, but in no way from wind instruments. If I am ever persuaded that this point of universal natural law must be understood, as is written to me; because after saying a thousand times, in my dissertation and in my letters, that in said system the separation of the physical from the demonstrative is impossible, and having had it experienced first-hand in many propositions, in spite of this on your side you want to strongly insist on the physical alone, independently indeed of the demonstrative. This is another problem, both of fact and of reason, as you necessarily want to separate that which is not divisible with regard to the system. The first problem (which is a lack of memory) must be solved on your part. The second problem I shall solve as a favour, not as an obligation. You must consider (and have the kindness not to forget) that the experiment so far has been done not only on the oboe, but on the trumpet and hunting horn. The third sound comes out wonderfully and clearly, with this addition, that the third sound becomes more perceptible in proportion to the greater strength of the instrument. What is interesting is that it is also produced by the human voice; but requires two voices that are quite constant in the matter of the intonation of the proposed interval. Because it was noted that, if either one voice or the other deviates a little bit from the physical point, the third sound is lost. Here you are then served with regard to the universality of the phenomenon given the two converging sounds. But I shall say again, this is as a favour and not as a debt; and only for the purpose of being able to complete this blessed examination once and for all. This being physically true, you should reflect on the fact that some time ago I answered your inquiry about whether this third sound was obtained from such and such instruments; I replied that I did not know, as I had not carried out any experiment; but that nothing of this mattered to me, because this third sound could either have been obtained from those such instruments, or not. If not, it would have been nothing to me. If yes, it would have been the same as that obtained with from the violin. Here then is the answer, physically verified. It is obtained, and it is the same. Please cease, therefore, to insist on percussion instruments, harpsichords, lutes, psalteries, bells, etc. It is a badly founded insistence. In such instruments, even a deaf man can tell the difference between the primary and main sound, which originates from the percussion, and the sound which originates in consequence of the undulations or vibrations of the struck body. But for this insistence to be over once and for all, Your Reverence should get two oboe players to come to your rooms and – with them positioned in the two furthest corners – play simultaneously with good intonation and a strong and sustained voice, the following intervals: & ww ww ww# terzi suoni etc: etc. third sounds