~~ 
194 IMPROVEMENT rn tHe HARPSICHORD. 
at the firft hearing, much refembling the diapafon ftop of 
an organ, And it is manifeft that if the touch be well 
regulated at firft, it will not afterwards be fubje& to alte- 
ration for a-long courfe of time. The touch is in part re- 
gulated by the ftrength of the ferpentine {pring and the 
number of its zig zag evolutions; and in part by the man- 
ner of rounding off the tip of the tongue; for the tip of 
the tongue muft not be cut off {quare, (in which cafe, the 
{tring would leave the tongue too abruptly and caufe a dif- 
agreeable twang,) but fhould be flanted off from under- 
neath, and its extreme point rounded and well polifhed 
by rubbing it very hard with a piece of black lead. As 
to the ftrength of the {pring, four fizes of wire, viz. from 
n° 4 ton” 8, will be fufficient for the whole inftrument ; 
but the touch is more immediately regulated by rounding 
off the tips of the tongues by the preflure and polifh of the 
black lead, more or lefs, as occafion fhall require. When 
the tongues are of wood, a ftroke or two of a fine file will 
be neceflary to take off the {quare edge left by the knife, 
previous to the polifhing it with the black lead. 
_ After all, a harpfichord juft furnifhed in this way, will 
not be fo pleafant to the touch or to the ear as it will be 
after a few weeks ufe; when the ftrings will, by repeated 
friction, have rounded off and polifhed the tips of the 
tongues, and have made for themfelves a broad bearing or 
contaét, which cannot perhaps be fo accurately produced 
by any care of the workman. 
Laftly, it is fearce neceflary to obferve that the ferpen- 
tine {pring and the root of the tongue muft be comprifed 
within the thicknefs of the jack; otherwife they will be 
apt to interfere with the firing behind, when the ftop is 
puthed back. 
F. HOPKINSON. 
Obfervations 
