1826.] Royal Institution^ t li^3 



great difficulty from not having any regular method, by which 

 he could find, at an instant's notice, the precise time at which 

 any given piece began to move, and also the state of motion or 

 rest, at the same instant, of all the other parts. He therefore 

 devised a method of expressing all the motions of any machine, 

 however complicated, by signs. This it is almost impossible to 

 describe without figures; butthe following statementof the infor- 

 mation which may be derived, almost at a glance of the eye, from 

 the paper on which the " mechanical notation " of any machine is 

 expressed, will serve to show the important purposes to which 

 the method may be applied, 



1. The name of each part is written at length, and there are 

 references from the name to all the di"awings. 



2. The number of teeth on each wheel, pinion, rack, or sector, 

 is seen. 



3. Any given part, a wheel for example, being named, it will 

 be seen what immediately moves it, what drives the mover, and 

 so on up to the origin of motion : and not only will the whole 

 succession of movements be visible, but the manner in which 

 they act ; as, for instance, whether by being permanently con- 

 nected, or in the manner of a pinion driving a wheel, or by stiff 

 friction, or at intervals only. 



4. The angular velocity of each part will be seen. 



5. The comparative angular velocity, or the mean velocity. 



6. All those parts which require adjustment will appear ; and 

 the order in which those adjustments should be made is pointed 

 out. 



7. At any part of the cycle of the engine's motion, it will be 

 seen at a glance what parts are moving, what are at rest ; and 

 it will appear in what direction the motions of the moving parts 

 take place, and whether their velocity is uniform or variable. It 

 will also be seen whether any given bolt or click is locked or 

 not. 



8. Any part being named, the entire succession of its motions 

 and intervals of rest is at once presented to the eye ; and if the 

 contemporary movements at any particular time be required, 

 they will be visible adjacent to it. 



Mr. Babbage gives, as specimens of his method, the mecha- 

 nical notation of the common eight-day clock, and of the 

 hydraulic ram. 



In consequence of the approaching fast and festival, the 

 Society then adjourned over two Thursdays, to meet again on 

 April 6. 



PUOCEEDINGS OF Till: ROYAL INSTITUTiON OF GKEAT 

 BRITAIN, AT THE FRIDAY-EVENING MEETINGS. 



Feb. 3. — The results of a chemical examination of caoutchouc 

 and the properties of the pure substance, were stated from thej 



