On Cog or Toothed Wheels. 139 
they take in the quantity and value of its pro- 
ductions; and it is obvious that any invention 
tending to divest these instruments of their 
imperfections, whether it be by lessening 
their expense, prolonging their duration, or 
diminishing their friction, must have a bene- 
ficial influence on the general prosperity. Now 
I apprehend that all these ends will be ob- 
tained in a greater or less degree, by having 
wheels formed upon the new system. 
I shall not content myself by proving the 
above theoretically, but shall present the so- 
ciety with wheels, the nature of which is to 
turn each other in perfect silence, while the 
friction and wear of their teeth, if any exist, 
are so small as to elude computation, and 
which communicate the greatest known velo- 
city without shaking, and by a steady and uni- 
form pressure. 
Before I proceed to the particular descrip- 
tion of my own wheels, I shall point out one 
striking defect of the system now in use, 
without reverting to the period when mecha- 
nical tools and operations were greatly infe- 
rior to those of modern times. Practical me-— 
chanics of late, especially in Britain, have 
accidentally hit upon better forms and’ pro- 
portions for wheels than were formerly used ; 
whilst the theoretic mechanic, from the time 
