On Music. 17% 
fervescence by the action of the acids, and contains a good 
deal of black and red oxide of iron: this friable stone is 
called kaloc, aud it is employed in building. 
<€ This is all we can say in answer to the questions upon 
the mineralogy of Cevlon. It is with much regret that we 
cannot better satisfy the curiosity of the learned on the 
subject: indeed, we have not yet been able to gratify our 
own, notwithstanding a stay of nearly seven years in the 
island. ; 
<¢ Before concluding this short notice, we shall hazard a 
conjecture, which to us has the appearance of probability at 
least ; it is, that the gems are formed in argillaceous veins of 
secondary ‘matters. If these stones were attached to the 
rocks, is it not probable that they would be sometimes 
found in the torrents attached to fragments of a stony na- 
ture? This is what we have never seen, although we have 
been often present at the rakings made by the natives in the 
beds oft torrents.’” 
XXIX. On Music. By Mr. Joun Farey. 
To Mr. Tilloch. 
SIR, cr 
I HAVE carefully perused the folio treatise on the Theory of 
Music, &¢. by Mr. William Hawkes, published in 1805 by 
Clementi and Co. of Cheapside, which you obligingly sent 
me a few days ago; which, though it may prove a useful 
work to theoretical musicians, contains little of novelfy, 
except its engraved examples, but what is to be found in 
am anonymous pamphlet, price 1s. (perhaps from the pen 
of the same author), entitled 4 Treatise on the Theory, and 
Practical System of Music, published by Cawthorne in 1798. 
The object of both of these works is, to recommend a tem- 
perament of the diatonic scale on keyed-instruments, as 
organs, harpsichords, piano-fortes, &c., in which each 
ascending FirtH is flattened by one-fifth of a comma as the 
instrument is tuned, except that the fifth above b E and the 
fifth 
