PRACTICAL PAPERS—IMPROVED MACHINERY. 
885 
brought together in the important machine which is to com¬ 
plete the shoe by uniting the upper leather and the sole. 
First, there is placed upon the form or last in this machine 
the inner sole. The upper leather is then stretched over this 
by means of small nippers attached to the machine, which are 
capable of stretching it with considerable force. It is secured 
in place by a row of small nails. The outer sole is then care¬ 
fully applied over the whole. As this has been entirely finished 
and polished on the edges in the previous process of prepara¬ 
tion, it is important that it be truly adjusted, since it cannot be 
afterwards trimmed. The machine then applies to the two soles, 
with the upper leather included between them, a force of press¬ 
ure of not less than three hundred kilograms, increased, if 
desired, to one thousand kilograms, or one ton. Screws are 
then inserted all around the margin of the sole, an operation 
completed in the most rapid machines in less than three min¬ 
utes for a single shoe, or in five minutes for a pair. The salient 
extremities of the screws an; put by a chisel, and the burr left 
by the chisel is ground away on an emery wheel. The last 
on which the shoe is constructed being made of iron, prevents 
the interior extremities from passing the surface of the inner 
sole. 
The machine is provided with an indicator, by means of 
which the exact distance desired between the screws may be 
easily preserved. For different sizes and kinds of shoe this 
distance will vary, as well as the size of the screw itself. Any 
kind of shoe may be made in the machine, from the coarsest 
boots to the thinnest dancing pumps. 
An important feature in these machines is, that they not only 
apply, but make the screw. The material is brass, which is 
drawn off from a bobbin in the machine as it is required. The 
extremity passes horizontally through a guide, and, in order 
to cut the thread of the screw, the whole bobbin revolves. In 
hand machines a crank serves to give the revolution ; but the 
driving power may be taken from a motor. When the resis¬ 
tance shows that the screw has struck the iron last, a cutter is 
brought into action by the foot of the operator pressing upon 
