a 
90 Dent's new Compensation Balance for Chronometers. 
Fig. 3, represents the plan of a compensation-balance, in which the two com- 
pensation-weights are each carried by a primary and a continuous secondary com- 
pensation-piece, which pieces are shown straight, in order to facilitate the clear 
understanding of the principles of my invention: although, in practice, I frequent- 
ly use a curved figure for the pieces, or make the primary and continuous second- 
ary compensations in one curved piece. 
a, is a simple balance-bar, made of Fig, 3. 
brass or other non-magnetic metal or 
metallic compound. 
b, two primary compensation-pieces 
of brass and steel, or other suitable met- 
als, which pieces are firmly fixed on 
the balance-bar a, nearly at the extrem- 
ities, and run parallel with it towards 
the centre. 
¢, two continuous secondary compen- 
sation-pieces attached to the free ends 
of the primary pieces b, and proceeding in a direction from the centre; the brass 
of these pieces is, in both cases, at the inside of the angle, and the steel at the 
outside. 
d, the compensation-weights. 
e, the timing-weights. 
The pieces 6 I term the primary compensation, because their 
action is to vary the inertia by bringing the compensation-weights 
d nearer to the centre of motion for an increase of temperature, 
and the reverse for a decrease; and it is to be distinctly under- 
stood, that this may be fairly considered as the only adjustment 
which the ordinary chronometer possesses, to correct the errors 
of the balance-spring. I have before remarked, that the com- 
pensation-weights, in the usual construction, do not go suffi- 
ciently in towards the centre of motion, on an increase of tem- 
perature ; while they come out too far ona decrease. I will now 
explain how the correction of this fault is to be accomplished by 
my invention. 
The secondary compensation-pieces c move the compensation- 
weights d on a change of temperature, in a direction nearly con- 
centric with the centre of motion, and thus produce but little va- 
riation as regards the times of vibration. 'These pieces I denom- 
inate the “ secondary compensation-pieces,”’ and their position is 
such, that the variation in the central distance of the compensa- 
tion-weights, due to a given change of temperature, is a max- 
imum ; that is, the variation which causes the secondary com- 
pensation only. 
For example ; on an increase of temperature, the weight d is 
moved further from the junction of the primary compensation- 
