The Sun.
London, England, 1849-06-30 00:00:00

ROTARY ENGINES.

The following account of an improved disc engine,
lately fitted up and used in driving the Times printing
machines, appears in the Builder. The engine gives
direct motion to a crank, upon which the shaft of the
disc exerts a uniform force. It is of simple construction,
and amongst other advantages is capable of being worked
at high or low pressure, and at from SO to 150 revolu•
Lions per minute:—

li6hopp's Disc Engine.—ln this engine, the advan-
tages of which have been long known, the objections
that alone kept it out of general use appear to have been
successfully overcome. It is a 16-horse power engine,
on the high-pressure and condensing principle ; it is,
however, equally suitable to be worked as a simple low-
pressure condensing engine. It stands in the machine-
room cloEe to a wall, and occupies a singularly small
space.* The shafting for driving the printing machines
is carried by brackets fixed to the wall over the engine,
and is driven by two bands; the drum on the engine-
shalt is 30 inches diameter, and the two pulleys over-
head 4 feet diameter.

" Our impressions in favour of the engine were con-
firmed by inquiry. It seems that before being erected at
the Times office it was tested, during a month, by Mr.
Penn, of Greenwich, and Mr. Farey (both good authori-
ties), in a corn-mill belonging to the former. The cora,
parison was made with a beam-engine of the best con-
struction, and, under similar circumstances, there was an
important difference in favour of the disc engine, the en-
gines driving alternately the same machinery, at equal
speed, from the same boiler. Several disc engines have
been fixed in various parts of the kingdom during the
last eight years, but the arrangements lately patented by
Mr. G. 1). Bishopp have so much improved it as to open
to it a mush larger sphere of action. This at the Tunes
office was manufactured by Messrs. Joseph Whitworth
and Co., of Manchester. The peculiarity of the disc en-
gine is, that it gives direct motion to a crank on the en-
gine shaft, and exerts a perfectly
throughout the revolution. uniform force on it
There are, therefore, no
" dead points," and when driving by gearing, without a
fly-wheel, there is no back •lash in the wheels. More-
over,
can be cut off at a very early part of
steamwithout
force. Other advantages besides the little
thet hv
ee r
driving
,stroke, the
space occupied are, that it can be fixed on the beams of
a floor, or on a slight foundation, and that, although
the speed of the piston (1. e., of the disc rings) is only
200 feet per minute, the engine makes three times as
many revolutions per minute as a common engine, and,
consequently, in most cases, much expensive gearing is
dispensed with. It appears to us admirably adapted for
driving the screw propeller direct, as the engine shaft
has only to be extended through the vessel, and have the
propeller fixed to it; it would thus enable the sailing
vessels which cannot spare much room to adopt the
screw as auxiliary power. The disc engines are now
made entirely from wooden patterns, and every wearing
surface, it is said, can be refaced, or renewed, as in en-
gines of common construction. We cannot but think
that this engine ought to come into general use."

Seven feet long and four feet wide ; and the highest part
of the engine is only three feet above the floor of the room.

DERBY ARBORETUM AN NIVERSART FRSTIVAL.—We
beg to call attention to the advertisement in another part
of our paper announcing the anniversary of the opening
of the above delightful grounds for Monday, the 2d of
July. The committee are making every exertion for the
occasion; they have made arrangements with the Electric
Telegraph
on the ground, and its wonderful powers of rapid corn-
Com' any to exhibit the electric telegraph
munication are to be explained. Mr. Jobn Farmer and
the principal vocal talent of Nottingham are engaged to
Assist in the vocal department, this being the first intro-
duction of it at this file. Several bands of music will be
placed in different parts of the Arboretum. The Railway
Company will run special trains from Birmingham, Shef-
field, Leicester, Nottingham, and Lincoln, at unusually
low rates, which no doubt will be the means of inducing
a great number to avail themselves of the opportunity of
being present at this great Midland Counties gathering.
The trees and shrubs look beautiful. By an advertiite-
inent in another part of our paper, it will be seen that
:he different shops of the town will close at two o'clock;
and, we understand, that the banks will also close at one.
—Derby Reporter.