$92 On the Invention of the Euphon, 
who, according to the then ufual cuftom, had converted the 
original Hungarian family name into that of Chladenius, 
was defirous that the author, his only fon, fhould apply him- 
felf tothe law, though it was contrary to his inclination. 
Dr. Chladni, therefore, ftudied law firft at Wittenberg, and 
then at Leipfic, and, after the ufual forms, took his degree 
of do&tor. On his father’s death he quitted this line, for 
which he had no attachment, and, devoting himfelf entirely 
to the ftudy of nature, delivered leGtures on phyfical and ma 
thematical fubjects to qualify himfelf for a profefforfhip 
which he had fome hopes of obtaining.’ In his 19th year he 
began to learn to’ play the harpfichord ; and he afterwards 
read a great many of the principal works on the theory of 
mufic, by which he found that the phyfico-mathemattcal 
- part of that fcience was far more defeétive than other branches 
of natural philofophy. Being therefore poffeffed with an 
idea that his time could not be better employed than in en- 
deavouring to make difcoveries in this department, he ac- 
cordingly tried various experiments on the vibrations of 
firings and the different kinds of vibration in cylindric pieces 
df wood, firft difcovered, through calculation, by the elder 
Euler; and found that, though a great deal had been faid on 
the 1ature of thefe elaftic bodies, yet the manner of vibra- 
tion and the proportion of tones in other elaftic bodies, which 
do not proceed, as in the former, in firaight lines, but de- 
pend on the vibration of whole furfaces, were totally un- 
known, and that the little which had been written on that 
fubjeét,’ by: fome authors, did not correfpond with nature. 
He had already long remarked, that every plate of glafs or 
metal emitted various tones according as it was held and 
{truck in different places; and he was defirous to difcover 
the caufe of this difference, which no one had ever examined, 
He fixed in a vice the axle of a brafs plate which belonged 
to a polifhing machine, and found, that by drawing the bow 
of a violin over it, he produced very different tones, which 
were {tronger and of longer duration than thofe obtained 
rniahas merely 
