186 IMPROVEMENT 1n THE 
examined the caufe of the quills being fo liable to break, 
and obferved that the piece of quill is thruft through a 
fmall hole in the tongue of the jack, projecting only about 
a quarter of an inch beyond the face of the tongue: That 
this quill is too fhort to yield in all its parts, and fo ac& 
properly as a fpring; but bends only at the place where 
it ifflues from the hole in the tongue, and works up and 
down as upon a hinge, in that place; and there only is the 
quill ever known to break. 
Thus in Plate III, Figure 6, a, is the tongue, 4, the 
quill fixed firmly in it, which being too fhort to a& fairly 
as a fpring, will bend only at c, when it is forced to pais 
the ftring ; and by repeated exercife muft neceflarily break 
in that part, as any {pring would do if compelled to a& 
in the fame manner. 
But if this quill could be made longer, or applied fo 
that its fpring fhould be part of a curve, it would proba- 
bly prefetve its elafticity for any length of time, as other 
{prings do. 
To effect this I have conftructed the tongue and applied 
the quill as reprefented in figure 7, where a, is the tongue, 
the top of which is rounded off ; the quill is firmly fix- 
ed in the hole at c, as ufual, but inftead of pafling through 
a length fufficient to ftrike the ftring, it is cut off even 
with the face of the tongue at f The quill thus fixed 
with its polifhed face downwards, is bent upward round 
the top of the tongue, and then proceeds horizontally the 
proper length; being kept in the horizontal pofition by 
the little wire ftaple e, being firmly driven into holes drill- 
ed for the purpofe, but not fo far as to pinch the quill 
againft the top of the tongue ; a little fpace being left for 
the quill to play in. 
From this conftruction it is manifeft, that the fpring of 
the quill will be in its whole length, but chiefly in the 
curve c, d; and that a quill fo applied will a fairly as a 
{pring, and may be expected to retain its elafticity for 
years, 
