lves is considered by
experts to be novel and very valuable.

In Fig. 3 is shown a pattern of a slide valve suited to special
purposes. Its working is essentially the same as that of the valve
already described. The ports are set side by side, parallel with the
sides of the valve. The supply port is in the middle, the other ports
lead to opposite ends of the cylinder.

[Illustration: Fig. 4.]

In Fig. 4 is shown another application of the controlling valve and
cut-off described above. Two oscillating steam cylinders are employed
in working the rudder. They are placed on opposite sides of the chest,
A, and are supplied with steam through the controlling valve, B. The
piston rods of the two cylinders are connected with cranks placed on
opposite ends of the shaft, C, at right angles to each other. Upon
this shaft, half-way between the pillow blocks which support it, there
is a worm which engages a toothed sector, D, on the rudder-post, E. To
an extension of the rudder-post is secured an arm, F, which is
connected with the arm, G, of the controlling valve. By shifting the
lever, H, the supply of steam to the two cylinders may be increased or
diminished, or its direction may be changed, so that the engines will
be reversed or stopped. This engine is remarkable for its simplicity.
The cylinders may be detached and changed if required, one size of bed
answering for three different sizes of cylinder, which may vary only
in diameter, the stroke being the same, so that the castings for
engines of different power are the same except in the matter of the
cylinders and pistons, and all the parts are interchangeable--a
feature of modern engine building that cannot be too highly valued.

Further information may be obtained from Herbert Wadsworth, 26
Merchants' Bank Building, 28 State street, Boston, Mass.

* * * * *

HOW OUR PATENT LAWS PROMOTE AND IMPROVE AMERICAN INDUSTRIES.

On another page we print in full a most suggestive paper recently
read before the Manchester (Eng.) Scientific and Mechanical Society,
by Mr. Frederick Smith, a prominent builder of that city, contrasting
the qualities, styles, and prices of American and English builders'
hardware--a paper which the _Ironmonger_ pronounces one of the most
serious indictments yet preferred against British workmanship in that
department.

The field covered by the paper--the supplying of house builders'
hardware--embraces a multitud