2 62 Mr. Babbage on a method of expressing 
and in order to render the velocity of the striking parts 
comparable with those of the time part, I have supposed one 
revolution of the striking fusee to be made in one minute : I 
have also taken one revolution of the scapement wheel, or 
one minute of time as the unit of angular velocity. 
The space entitled comparative angular velocity, expresses 
the number of revolutions one wheel makes during one re- 
volution of some other ; it differs from the real angular 
velocity, because one wheel may be at rest during part of 
the time. Thus the clock strikes 78 strokes during twelve 
hours, or one revolution of the hour hand : if this be called 
unity, the pin wheel moves through 78 pins or 9J revolutions 
in the same time ; its comparative angular velocity is there- 
fore 9J. 
The space in which the origin of motion is given, will not 
require any explanation after reading the description of the 
signs employed in this paper. 
The adjustments are numbered in the order in which they 
are to be made. No. 1, is attached to the crutch: the first 
adjustment is to set the clock in beat. No. 2, is to adjust the 
length of the pendulum to beat seconds. No. 3, occurs in 
three different places, at the hour and minute hands, and at 
the snail on the hour wheel. It is necessary that when the 
hour hand is at a given figure, three o'clock for instance, 
that the minute hand should be set to twelve o’clock ; it is 
also necessary that the snail should be in such a position that 
the clock may strike three. These adjustments must be 
made at the same time. No. 4, is for the adjustment of the 
seconds hand to 60 seconds. No. 5, is double, and is for the 
adjustment of the minute and hour hand to the next whole 
