298 Mr. J. C. DYER ON 



engaged tlie labours of many ingenious and able mecha- 

 nicians through a long course of years to bring them from 

 a rude state into their present very accurate form of 

 working. Hence it seems desirable to place on record 

 an account of the successive changes and inventions 

 that have been applied to this class of machines^ as being 

 a useful contribution to the " History of Inventions " 

 connected with cotton-spinning during this century. 



A retrospect of this period will show our advanced and 

 advancing knowledge of the " mechanical sciences reduced 

 to practice/^ to be the main source of our wealth and 

 power as a nation; wherefore it will be held useful to 

 have as full and fair notices as can be obtained of the 

 progress in the several inventions that have led to the 

 final success of the most intricate and scientific kinds of 

 machinery now in general use. 



To make these roving-frames work safely^ and with the re- 

 quisite accuracy in their several complex movements^ was no 

 easy task ; and many even of its constructors were unable to 

 comprehend the principle of action to be brought under 

 such exact control to make it work safely. To render 

 this more evident^ it will be necessary to trace the succes- 

 sive operations required to reduce the slivers from the draw- 

 ing-frames to the proper state for spinning. 



The rovingSj after being equalized by repeated doubling 

 and drawing, are brought (in tin cans) to the roving- 

 frame, by which they are again reduced by the drawing- 

 rollers, and then pass through the neck of the throttle- 

 spindle and down one arm of the flyers, through a hook, 

 from which they pass to, and are wound upon, the barrels 

 of the bobbins. A slight twist is given to the rovings by 

 the flyers, to prevent their being stretched in their passing 

 to the bobbins. Supposing, in commencing, the diameter 

 of the front rollers and that of the bobbin-barrels to be ex- 

 actly the same, it is obvious that the rotative speed of the 



