ving the nail. The nail is split for one half its
length, and the two arms thus formed are slightly separated at the
point, so that when they meet the ridge at the bottom of the hole they
will be still further separated and will clinch in the body of the wood.

[Illustration: TOOL FOR DRIVING AND CLINCHING NAILS.]

This invention was recently patented by Mr. Charles P. Ball, of
Danville, Ky.

* * * * *

AUTOMATIC BALANCE ATTACHMENT FOR VALVES.

It is well known that in all air compressors and water pumps the
pressure in cylinder of air compressors or in working barrel or cylinder
of pumps is much greater at the point of opening the delivery valves
than the actual pressure in the air receivers of compressors or in water
column of pumps because of the difference in area between the top and
bottom of delivery valves. In some air compressors a hundred and
twenty-five pounds pressure to the square inch is required in the
cylinder to eighty pounds in the receiver, and in some instances a
hundred pounds pressure is required in the cylinder to eighty pounds
pressure in the receiver or column.

The engraving shows an invention designed to remedy this defect in air
compressors and pumps, to provide a device which will enable the
compressors and pumps to operate with equal pressure on both sides of
the delivery valve.

The invention consists of an auxiliary valve arranged outside of the
cylinder, where it is not subjected to back pressure, and connected with
the delivery valve by a hollow valve stem.

In the engraving, which is a sectional view, the cylinder of an air
compressor is represented, on the end of which there is a ring
containing delivery ports, through which the air from the cylinder is
forced into a receiver or conducting pipe. This ring is provided with an
inner flange or valve seat on which rests the delivery valve. These
parts are similar to those seen in some of the air compressors in common
use, and with this construction and arrangement one hundred pounds
pressure to the square inch in the cylinder is required to open the
valve against eighty pounds pressure in the receiver or in the
conducting pipes.

[Illustration: AUTOMATIC BALANCE ATTACHMENT FOR DELIVERY VALVES OF AIR
COMPRESSORS AND WATER PUMPS.]

A drum having an open end is connected with the cylinder head by
inclined standards, and contains a piston connected with the valve by
means of a rod that extend