THE COPYING OF AMERICAN MACHINERY 263 



machines. In place of the single tool used in a common 

 lathe, six, eight, ten, and in a few instances as many as twenty 

 tools are taken in charge by a revolving turret which brings 

 them round, each to fulfill its own proper function at the 

 exact instant when it is required to come into action. Each 

 tool fulfills its own distinct duty, and the result is, that when 

 the turret has revolved once, a single article of manufacture 

 will have had the half dozen, dozen, or more separate cutting 

 operations performed on it necessary for its completion. In 

 some instances two separate pieces will be produced during 

 a single rotation of the turret. 



This device also originated in America previous to the 

 middle of the last century, and that country reaped the solid 

 advantages of its successful employment for many years 

 before British firms saw much in it. When the manufacture 

 was at last taken up in Great Britain, it remained in a crude 

 form, while American firms still went on improving until they 

 made the movement of the machine wholly automatic. Now 

 many British firms are wisely following that example with 

 beneficial results. But here also much leeway has to be 

 made up. 



Toothed or cog wheels are used in very large quantities 

 in machinery. The common British practice has been to 

 cast them roughly and inaccurately from patterns ; the Amer- 

 ican, to cut the teeth cleanly and truly from solid iron, steel, 

 or brass. In the exceptional British practice the machines 

 designed for cutting teeth have, until very recent years, 

 required the constant attendance of one man, and the majority 

 made do so now. American machines, on the contrary, 

 are so constructed that the attendant need not come near 

 them from the time of putting in the wheel which has to be 

 cut until all the teeth are finished. The machine rings a bell 

 to let him know when the work is finished, and then it stops 

 forthwith. I was in a shop where a machine of this kind was 

 left to run all night, doing work without any attendance. 



The bevel cogwheels that drive some of the chainless 

 cycles afford a remarkable illustration of the highest spe- 

 cialization in this line of American manufacture. For cutting 

 the teeth of these a special machine, which I have seen in 



