148 Mr. Atwood's Investigations for determining 
the axis T R in the direction of the arc Ob; p is a curved 
pallet fixed to the axis T R, which receives the tooth of the 
balance wheel near the axis ; the tooth proceeding along the 
curved surface by the force of the main spring, turns the axis 
and the annexed arm G O in the direction of the arc O h, and 
at the same time winds up the auxiliary spring u. A small 
projection at the extremity of the curved surface of the pallet 
p prevents further progress of the tooth, when the arm O G has 
been turned through an arc Ob* of about 2 7 0 ; consequently 
the spring u has then been wound through the same arc or angle 
OG/j = 27°. 
F S is another axis in the same right line with CADH, 
exactly similar to that which has been described. This 
axis F S carries with it the arm I O ; the auxiliary spring v is 
annexed to this axis, and is wound up when the axis is turned 
in the direction of the arc Ok. q is a pallet similar to the 
former pallet p, and is placed so as to receive the tooth of the 
balance wheel, which by its action on the pallet winds up the 
spring v, and carries the arm O I through an angle OH’, = 
27 0 , further motion being prevented by a small projection at the 
extremity of the pallet q, similar to that which has been already 
mentioned. I m represents the balance wheel, the upper tooth of 
which acts on the pallet p, and the lower tooth on the pallet q, 
alternately winding up the auxiliary springs u and v, in the 
manner described in the subsequent page : the axis of the 
balance wheel n 0 is parallel to the line C O or G O. 
The several arcs expressed on the circumference of the ba- 
lance, i. e. O Q, O b, ON, O k, are equal to the respective arcs 
denoted by the same letters in the circumference of the circles 
described by the extremities of the arms G O and I O. 
♦ Vide infra the note in page 150. 
