Colonel Beaufoy Wooden Pendulum. 355 
has two resultant axes lying in the plane of the laminae ; — by 
the want of regular cleavages, — -and by its solubility in acids. 
^RT. ^'^l.—Eocperiments on the Going of a Clock with a 
Wooden Pendulum. By Colonel Beaufov, F. R. S. &c. he. 
In a communication to Dr Brewster. 
In order to determine what reliance could be placed on the 
going of a clock with a wooden pendulum, I fitted one of my 
monthly regulators, beating dead seconds, and whose motion 
continued whilst winding up, with a straight-grained cylindrical 
deal-rod ; but being dissatisfied with the irregularity of the rate, 
I was on the point of abandoning this, when, from the circum- 
stance of the clock becoming much out of beat, I concluded that 
the great source of error might probably proceed from the warp- 
ing of the wood. I therefore caused the intermediate portion of 
the deal, about an inch below that part where the watch-spring 
which suspends the pendulum is fastened to the upper part of 
the bob, to be reduced from a cylindrical to an elliptical shape, 
the transverse or longest diameter .being parallel to the back 
of the clock. This alteration so much improved the going, that 
I am induced to trouble you with a Table containing the rate 
for months, and to remark, that the rod was perforated in 
the centre for the crutch to pass through, and a brass eye in- 
serted to prevent the wearing away of the wood. To render 
the pendulum steady, it was hung independent of the frame 
that supports the clock ; and the bob, in lieu of being screwed 
to the rod, was permitted to rest upon a divided nut, turning 
on a fine screw, attached to the lower extremity of the rod, and 
which answered the twofold purpose of supporting this weight, 
and regulating the pendulum. The advantage of permitting 
the bob to remain unconfined to the rod, is, that the expansion 
of the bob upwards has a tendency to counteract the expansion 
of that spring by which the pendulum is hung downwards, and 
of therefore preserving the same length. By examining the 
Tables, it will be found, that the accuracy of the simple pen- 
dulum described, is little inferior to the compound one known 
by the name of the Gridiron Pendulum ; and when it is consi- 
dered that the latter costs IS guineas, and the rod not as many 
z 2 
