Dent's new Compensation Balance for Chronometers. 93 
Fig. 6, is a perspective view of a balance 
of the same kind as Fig. 5, but in this case, 
the continuous secondary compensation- 
pieces, each made in the form of one staple 
only, stand across the primary compensa- 
tion-bar at right angles; which is an essen- 
tial condition of this construction, because 
a single staple compensation will not raise 
the weight perpendicularly from the end of 
the bar; therefore the bow of the staple 
should be placed in a position which will 
raise the weight, without producing more 
variation in the time than is unavoidable. 
In order to adjust the secondary compen- 
sation of the balances shown in figures 4 and 
5, if in excess, the staples must be shortened 
or thickened; and the reverse must be done, if in defect: the primary compensa- 
tion is adjusted, by varying the height of the weight v, on the screw wu, according 
to the usual practice. 
My patent further consists in the introduction of a remontoire- 
escapement into a chronometer or other portable timekeeper. ‘The 
remontoire-spring being wound up at regular intervals by the 
main-spring through the train of wheels, gives an invariable im- 
pulse to the balance by means of an impulse-escape-wheel. 
The principle of this escapement, now introduced into a chro- 
nometer, may be considered the same as that lately invented by 
G. B. Airy, Esq., Astronomer Royal, who furnished me with 
the drawings from which I recently constructed the first astro- 
nomical clock containing his escapement. 
Mr. Airy having generously given his invention to the public, 
I have adopted those parts of it which were applicable to a chro- 
nometer ; and have succeeded in preserving the ordinary detach- 
ed escapement, (which has so long and so deservedly maintained 
its undisputed preéminence, ) and uniting in conjunction with it 
such adaptations as to convert it into a remontoire-escapement for 
a chronometer. 
The result of this combination is, that a constant impulse is 
given to the balance by the impulse-escape-wheel, without its re- 
ceiving any lateral pressure from the usual train of wheels; for 
that of the remontoire-spring can hardly, with justice, be so 
called. 
London, Nov. 1, 1842. 
