HOR 
is lowest when the rate is most quick. 
Thus if one of the two adjusting screws in 
fig. 7, were downwards, in the position of 
quickest rate, that screw would require to 
be screwed a very- little quantity inwards, 
and the opposite screw to be screwed a 
like quantity outwards, in order to remedy 
this imperfection without much change in 
the other adjustments. And if a like im- 
perfection were found in the vibrations of 
the balance, when tried in a vertical posi- 
tion, having the lowest point at rest, in a 
line at right angles to the line passing 
through the radii, a similar alteration must 
be made in the expansion weights, either 
by a. careful flexure of the circular arcs, 
or by altering the quantities of those 
weights ; or else by means of small screws 
tapped into the weights themselves, and 
directed towards the centre, like the 
weights at the extremities of the radii. 
By these, and other correspondent means, 
the balance may be made to keep time, in 
all those positions wherein its plane shall be 
perpendicular to that of the horizon ; but 
even in these trials, very great pains and la- 
bour may be required to produce a high 
degree of accuracy ; and in this course of 
operation, the skilful workman may be un- 
der the necessity of preparing a great num- 
ber of expansion weights, and regulating 
screws, to be applied in trial, whenever the 
course of adjustment in one part shall carry 
him beyond the general conditions of the 
whole machine. And after all, as the quan- 
tity of action, in the spring, must alter the 
quantity of pendulous effect, in this curious 
and delicate time-ineasurer, it may be 
doubted, whether the adjustments for posi- 
tion in the vertical balance can be effectual 
any longer than while the arcs of vibration 
continue permanent, ibis consideration 
leads us to the necessity of an adjustment 
in the maintaining power, in order that the 
vibrations shall not fall off; at the same 
time that it affords one of the strongest ar- 
guments in favour of a remontoire, notwith- 
standing the experiment of Arnold, which 
showed that a sea-chronometer (face up) 
kept the same rate, when those arcs were 
greatly varied. 
When the balance has been adjusted for 
position in the vertical situation, it does not 
follow, as a matter of course, that it will 
keep the same time with its plane horizon- 
tal, or face up and face down. In the for- 
mer cases, the effect of gravity still appears 
to be combined with that of elasticity, 
though tinder circumstances of adjustment ; 
HOR 
in the latter, gravity seems to be out of the 
question. If the rate should demand ad- 
justment with the axis vertical, in order to 
make it agree with that which obtains when 
the balance is vertical, it appears necessary, 
that either the inertia or the elastic force 
should be altered. The former seems to 
demand such changes of the screws or 
weights, as may alter the effective radius of 
the balance; the latter requires a change 
of the spring itself. The artists with whom 
the writer of this article has conferred, did 
not seem to have clear notions of any direct 
method for effecting the purpose here 
pointed out. It' appeared, that they have 
recourse to several expedients ; but that, 
in general, the rate, face up, of a time-piece, 
which has been well adjusted in other re- 
spects, does not require much additional ad- 
justment. 
Front all these considerations, with others 
into which brevity forbids ns to enter, to- 
gether with those which relate to the choice 
and preparation of materials, and the deli- 
cacy and truth of workmanship, the reader 
will be able to form some judgment of the 
intelligence and skill with which, chiefly 
under the sanction of the British govern- 
ment, this important manufacture has been 
pursued, and likewise of the ample field for 
improvement, which remains for the exer- 
tions of future artists. See Pendulum, 
Clock, Train, and Watch-work. 
HOROPTER, in optics, a right line 
drawn through the point where the two 
optic axis meet parallel to that which joins 
the centres of the two eyes or the two 
pupils. 
HOROSCOPE, in astrology, is the de- 
gree of the ascendant, or the star that rises 
above the horizon at a certain moment, 
which is observed in order to predict some 
future event, as the success of a design, 
the fortune of a person who was at that in- 
stant born, &c. The same name is also 
given to a scheme or figure containing the 
twelve houses, in which are marked the 
situation of the heavens and stars, in order 
to form predictions. See House. 
Horoscope lunar, the point from whence 
the moon proceeds when the sun is in the 
ascending point of the east. 
HORS de son fee, an exception to avoid 
an action brought for rent issuing out of 
certain lands, by him that pretends to be 
the lord, or for some customs and services ; 
for if the defendant can prove the land to 
be without the compass of his fee, the ac- 
tion fails. 
