WAT 
balance wheel, m, if there was no obstruc- 
tion, would turn with great velocity until 
all the chain was wound otF the fusee ; but 
one of the pallets of the verge is always en- 
gaged with one of the teeth of the wheel, 
suppose one of the teeth on the lower side ; 
now, by the balance turning round to make 
a vibration, the pallet allows the tooth to 
slip off, and the wheel begins to run down 
by the action of the main-epring, marking 
the vibrations by moving the hands G H ; it 
is, however, stopped immediately, by the 
next tooth at the top of the wheel meeting 
the upper pallet of the verge: the balance 
and pallet was at that time just beginning 
to return, and the top of the wheel moving 
in contrary direction to the bottom, the 
tooth presses against the pallet, and assists 
the balance to maintain the same arc in its 
vibration : when the balance is about to re- 
turn, the upper tooth of the wheel slips off" 
the pallet, and the lower one catches on the 
lower pallet, and assists the balance as be- 
fore ; one of the pivots of the balance wheel 
w oiks in a small frame, y, called the pot- 
tance ; the lower pivot of the verge works 
in the bottom of it also, and the upper pivot 
turns in a cock, F, screwed to the plate E, 
and covering the balance to defend it from 
injury. ’ 
The hands, G H, are moved by the cen- 
tral arbor which projects through the lower 
plate, E, (fig. 6) and receives a pinion of 
twelve teeth fixed on the end of a tube 
which fits tight upon the arbor, but will slip 
round easily to set the hands when the 
watch is wrong : the other end of the tube 
is square, and receives the minute hand, H, 
which points out the minutes on a circle of 
sixty upon the dial plate M M ; the pinion 
on the tube turns a wheel, L, of forty-eight 
(seen in plans in fig. 3) on whose arbor is 
a wheel of sixteen, turning another wheel, 
K, of forty-eight, the arbor ot vvhit h is a 
tube fitting on the other tube, and has the 
hour hand, G, fixed upou'it: by tins arrange- 
ment the minute hand, H, turns round 
twelve times for one revolution of the hour 
hand, G. 
As the time the-balance takes to perform 
a vibration depends upon the arc it passes 
through, the least increase of force in the 
main-spring would alter the rate of the 
watch; therefore the fusee is cut into a 
spiral, diminishing from top to bottom, as 
the spring draws tlie chain with greater 
force when wound up than when it is more 
released. The chain acts upon a shorter 
leyer when the spring is wound up, and 
WAT 
npon a longer when it is down, so as to re- 
gulate the unequal action of the spring to a 
perfectly regular force upon the wheel 
work. 
As it will most probably happen that a 
w'atch will not always keep the same time, 
it is necessary to have an adjustment that 
mai^ cause it to move faster or slower : this 
can be done by two ways, either by increas- 
ing or diminishing the force of the main- 
spring, a, which increases or diminishes the 
arc the balance describes ; or it may be 
done by strengthening or weakening the 
pendulum spring, o o, which will cause the 
balance to move quicker or slower. The 
first is done by turning the rachet wheel, b, 
(fig. 5 and 3) on the end of the arbor of the 
main-spring, thereby winding up or letting 
down the spring without turning the fusee ; 
but as this is a very coarse adjustment, it is 
never used but by the maker, and recourse 
is had to the pendulum spring, o, (fig. 2) 
which is fixed to a stud, r, upon the plate 
E, by one end, and the verge of the balance 
by the other: p is a small piece of metal, 
called the curb, having a notch in it to re- 
ceive the spring : the acting part of the 
spring is from p to the centre ; and as the 
curb, p, is moveable, the acting loiigth can 
be altered : the curb is cut into teeth, and 
turned by a pinion, q, (fig. 4) which repre- 
sents the piece, sssss, detached from the 
plate, E, and turned up : the pinion, g, has a 
small dial, divided into thirty, fixed to its 
arbor on the upper side of the plate, s s, by 
which it can be set so as to regulate the 
watch to the utmost nicety : tttt (fig. l) 
are four pillars by which the two plates, 
E E, of the watch are held together ; and 
tttt (fig. 2) represent the heads ot the 
same pillars coming through tlie upper 
plate, and small pins put through to keep 
the plate down. 
WATER, a transparent fluid, without 
colour, smell, or daste, in a very small degree 
compressible ; when pure, not liable to 
spontaneous change ; liquid in the common 
temp'erature of our atmosphere, assuming 
tlie solid form at 32'* Fahrenheit, and the 
gaseous at 212“, but returning unaltered to 
its liquid state on resuming any degree of 
heat between these points, capable 6f dis- 
solving a greater number of natural bodies 
than any other fluid whatever, especially of 
those known by the name of the saline ; 
performing the most important functions in 
the vegetable and animal kingdoms, and 
entering largely into their compo-sition as 
a constituent part. Water is formed of 
