Te Mr. HowarpD GRUBB, 
each part, showing the machine in every possible position, but 
this would require enormous labour, and numerous sets of draw- 
ings for each individual position of the machine, and such, even 
if accomplished, would not fulfil the required conditions, for it 
would be almost impossible for any person to properly follow the 
various motions through these elaborate drawings, and carry in 
his mind the true nature of the movements. 
Mr. Babbage’s system, however, enables a person who has a 
slight mechanical knowledge, and a very little practice, to per- 
fectly understand the complicated movements of a piece of 
machinery like this automatic numbering machine,* from a few 
minutes study of a single chart, on which all its motions are 
laid down according to his system. 
Secondly. The principle of this system of notation may 
be thus described :—The various movements of the machine are 
classified, and named, and placed, one under the other in the first 
column of the sheet. Opposite them is a portion ruled into small 
vertical columns, which in its total horizontal dimensions is sup- 
posed to represent a certain space of time, in fact the time 
occupied by the machine in completing one period or cycle of its 
duty. This may be divided into any convenient number of parts. 
In the present case as the machine completes a cycle in about 
six seconds, I have divided the space into six parts, and each of 
these again into ten, representing tenths of seconds. 
The vertical distances represent, on various empirical scales, 
“spaces” travelled over by that particular part of the machine 
specified in the first column. 
As the horizontal distances represent “time,” and the vertical 
space, any portion of a machine at rest for any particular number 
of seconds, or tenths of seconds, is represented by a horizontal 
line, thus :— 
LT UL 

| : 
cn 
* An automatic numbering machine, the invention of Mr. Thomas Grubb, r.rs, was 
exhibited as an illustration to this paper. 
