260 
Mr. Babbage on a method of expressing 
10. If a bolt may rest in three positions : ist, bolted on 
the right side ; 2nd, unbolted ; 3rd, bolted on 
the left side. When it is unbolted, and in the 
middle station, use two lines whilst in the act of 
unbolting, and two lines of dots, one on each side 
of, and close to the indicating line, whilst it rests 
in this position. When it is bolted on the right 
side, a line or a line of dots at a greater distance 
on the right hand from the indicating line will 
represent it. And if it is bolted on the left, a 
similar mode of denoting it must be used on that 
side. Any explanation may, if required, be put 
in words at the end of the notation, as will be 
observed in that of the hydraulic ram, Plate IV. 
I have now explained means of denoting by signs almost 
all those circumstances which usually occur in the motion of 
machinery : if other modifications of movement should pre- 
sent themselves, it will not be difficult for any one who has 
rendered himself familiar with the symbols employed in this 
Paper, to contrive others adapted to the new combinations 
which may present themselves. 
The two machines which I have selected as illustrations of 
the application of this method, are, the common eight day 
clock, and the hydraulic ram. The former was made choice 
of from its construction being very generally known, and 
I was induced to choose the latter from the apparent difficulty 
of applying this method to its operations. 
The advantages which appear to result from the employ- 
ment of this mechanical notation , are to render the description 
of machinery considerably shorter than it can be when ex- 
