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by signs the action of machinery. 
pressed in words. The signs, if they have been properly 
chosen, and if they should be generally adopted, will form 
as it were an universal language ; and to those who become 
skilful in their use, they will supply the means of writing 
down at sight even the most complicated machine, and of 
understanding the order and succession of the movements of 
any engine of which they possess the drawings and the me- 
chanical notation. In contriving machinery, in which it is 
necessary that numerous wheels and levers, deriving their 
motion from distant parts of the engine, should concur at 
some instant of time, or in some precise order, for the proper 
performance of a particular operation, it furnishes most im- 
portant assistance ; and I have myself experienced the ad- 
vantages of its application to my own calculating engine, 
when all other methods appeared nearly hopeless. 
DESCRIPTION OF THE PLATES. 
Plates VII. and VIII. are different representations of an eight 
day clock, for the purpose of comparing it with the notation. 
Plate IX. represents the mechanical notation of the same 
clock. 
Under the names of each part follow the letters which 
distinguish them in the plates. 
The next line contains numbers which mark the number 
of teeth in each wheel, pinion, or sector. 
The following line is intended to contain numbers expres- 
sing the linear velocity of the different parts : in the eight 
day clock this line is vacant, because almost all the motions 
are circular. 
The next line indicates the angular velocity of each part ; 
mdcccxxvi, . M m 
