149 
low numbers, but it could not.be made applicable to rovings for 
fine spinning ; but the pressing of the rovings hard upon the 
bobbins in the tube frame rendered the application of the 
presser to the fly frame of great importance. After many 
experiments this object was effected, and the application of 
the presser to the bobbin and fly frame was carried into effect 
by means of springs, or the centrifugal action of revolving 
weights attached to the arms of the fliers, and both of these 
methods were set forth in the patent for those improvements. 
Nevertheless several competing parties afterwards obtained 
patents for very trivial changes, called “ inventions,” for 
applying the said spring and centrifugal actions to press the 
rovings upon bobbins. 
The differential motion of the bobbin and fly frame con- 
tinued very imperfect until Mr. Henry Houlds worth’s import- 
ant invention of a self-adjusting apparatus for giving the 
differential motions required. This discovery of a very 
simple train of movements for securing the required rotations 
of the delivering rollers of the bobbins and of the fliers 
will at once be recognised as an invention of a high order 
in mechanical science. From the limits of this abstract 
the main features only of these delicate movements can be 
given, and for the details the paper must be consulted 
in extenso. I may here add that about sixty years ago 
Mr. John Kennedy employed rotating tin cans for giving- 
twist to rovings ; but as they could not be driven with suffi- 
cient speed, the old throstle spindle, enlarged to suit rovings, 
was adopted for the frames called the “ slubber” and the 
“ bobbin and fly,” and these frames, with many improve- 
ments by the same gentleman and others, were in extensive 
use until partially superseded in the year 1828 by the tube 
frame as before mentioned; and the suggestive nature of 
new inventions and discoveries as leading to the production 
of others is strikingly shown in the successive applicationof 
those in the tube frame to the bobbin and fly, as before said. 
