172 



Mr. Howard 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 : — 





* An automatic numbering machine, the invention of Mr. Thomas Grubb, f.rs, was 

 exhibited as an illustration to this paper. 



