CANAL LOCKS. 351 



ley at either end, will put the carriage in motion, arid improvement 

 thereby raise or depress the water in the lock, and that to to save water 

 do so, the two-pound weight will descend sixteen inches. *" "°^ ^^^^ 

 Hence, two-pounds descending sixteen inches, may be 

 deuoted the cause or power to produce the effect. Far* 

 ther, it follows, that this two-pound weight descending 

 sixteen inches produces the same operation as fifty-six 

 pounds laid in the caisson would perform, and this sink- 

 ing of the caisson D may be denoted the direct effect pro- 

 rinccd by the two-pound weight. The indirect and requi- 

 site effect being that of depressing or elevating the water 

 in the lock C, and the comparison thereon will stand 

 thus : the surface of a body of water, of an area of 

 twenty-four inches by ten, is raised about four inches 

 and a half by the power of two pounds descending six- 

 teen inches ; and, vice versdy by reversing the poWer. 

 the water is again depressed. 



The shuttle z, between the lock and the caisson cham- 

 ber, will regulate the time of the ascent or descent of the 

 caisson. 



R, SAi^MON. 



JVobtirn, ^SdJjml, 1S05. 

 Charles Taylor, Esq. 



Sir, 



In reading over the copy of the paper which I hastily 

 drew up, and sent with i^y model, I observe that I 

 omitted making any remarks on its applicability, im- 

 provements to be made in the carriage to facilitate ^the 

 moving of the load, and on the different other ways, be- 

 sides the one shewn in the model, by which it may be put 

 in action. 



It will readily occur to every engineer, that this sort of 

 lock is not confined to the particular shape of the model, 

 or to any particular form. The caisson chamber may be 

 placed endwise to the lock ; may be of any shape, and 

 placed at a nearer or further distance, as may be re- 

 quired. 



On comparing the length and movements of the frames 

 BBb2 in 



