t 2 3+ ] 
Since I left th~- Caufeway, I have been inform'd, 
that commonly, if the top of the hone in a pillar is 
found either concave or convex, the top like wife of 
every hone of that pillar is either concave or convex 
in the fame manner j which may be a fubjeCt for fu- 
ture obfervation. 
It feems probable, therefore, that all the ends 
were originally fpherical : fome of the hones, it may 
be, exaCt fpheres ; others, oblate fpheroids ; and fome 
longer hones in a cylindrical form, and of a fpherical 
figure, at each end. To which conjecture I have 
been led, by obferving the hiape of fome I have, and 
of two models of two hones reprefented in cork by 
Mr. Drury, who presented the profpeCts of the Caufe- 
way engraved to the Royal Society, from the draw- 
ings of his fiber Mrs. Sufanna Drury. One of thefe 
is convex at both ends j and I have fome in the fame 
hiape. This fpherical figure has been altered by the 
prehure, in the manner I have obferved : for, in 
the other model, part of the fpherical figure is feen 
round the fides towards the concave end ; and I have 
one exactly of the fame kind. In thofe alfo, which 
I have, that are at the fame time partly convex and 
partly concave, the convex part feems to have been 
the natural figure of the hone, as before deferibed j 
for, where both ends are concave, that, which was 
probably prefs d by a harder hone form'd before it, 
is perfectly concave ; whereas that concavity, which 
is made by a hone probably form’d after it, is not to 
perfectly concave as the other • but it commonly re- 
mains convex in fome part, as obferved before 5 dwell- 
ing out like a cufhion prefs’d by any weight. 
By 
