644 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1914. 
Sooner or later this suggestion of Leonardo’s was practically 
adopted, and the spinning wheel, fitted with bobbin and flier, came 
into general use in Kurope. The distaff and spindle, however, have 
not, even to this day, been altogether superseded. 
A more compact and convenient contrivance for spreading the spun 
thread upon the bobbin is shown above Leonardo’s sketch. In place 
of the fork for altering the relative position of the flier and bobbin, 
a row of small hooks is placed along the arm of the flier, by means of 
which the thread ean be guided on to the bobbin at any part of its 
barrel. This is the twisting and winding arrangement with which 
the improved spinning wheels of the seventeenth century in Europe 
were fitted up. 
In order to compare it with Leonardo’s sketch I have to the right 
of it (fig. 22) made a diagram of the bobbin and flier of a machine 
spindle. 
It is old-fashioned now, as a modification of it, called the ring spin- 
ner, has taken its place. The principle on which it works, however, 
is the same, so, as it is more convenient to compare with the original 
sketch, I prefer to use it. 
Here Nos. 1 A and 1 B indicate the spindle, which is caused to re- 
volve by the pulley, No. 2. 
The machine spindle is fixed vertically, a hundred or two being 
ranged on one machine. 
The flier, No. 3, is fixed at the top of the spindle. 
No. 4 is the bobbin standing on a shelf, No. 5. The shelf is made 
to rise and fall automatically as the thread is delivered to it from the 
flier. This is, therefore, a return to Leonardo’s idea of the shifting 
spindle. . 
The spindle passes through the bobbin, but there is no hollow shaft 
for causing the bobbin to revolve. It simply stands loosely on the 
shelf, and when the thread from the flier is attached to it, the revolv- 
ing flier drags the bobbin round at a less speed than its own, the 
weight of the bobbin acting as a brake. The thread is thus wound 
cn more or less quickly, according to the weight of the bobbin. 
In the ring spinner before mentioned the bobbin, or paper cop, is 
fixed firmly on the spindle and the flier is free. The flier runs on a 
ring which encircles the cop and drags upon it. This acts in the same 
way, as to winding, but makes it possible for the spindle to revolve at 
a much higher speed. 
Although thus adopted for machine spinning, the idea of a loose 
bobbin was not, I believe, a new one. Spinning wheels had probably 
been previously fitted with loose bobbins, such as that shown in the 
diagram, above Leonardo’s drawing. In this case the fixed flier is 
revolved by a pulley, which is connected by a belt to a large wheel. 
The loose bobbin, if not heavy enough to act as its own brake, has a 
