‘ 
-and the length of its stroke. 
160 
linders upon their. pistons) without in- 
terposing a beam, crank, or other con- 
‘trivance, between the rectilinear and the 
retative, as in the engines now 1n usé; 
and which engine, thus combined, per- 
forms, the filling and discharging itself of 
steam In a superior manner, without the 
aid of valves, .or cocks, of course the 
gear called hand-gear,-is also rendered 
unnecessary. _ As, however, there are 
other rotative engines which move with- 
out beam, crank, &c. Mr. Witty thinks 
jt necessary to state in what his inven- 
tion differs from these. ‘* In the latter” 
{referring to the engines of others) he 
says, “a piston or pistons, have been 
made: to revolve round a-centre, or 
round a drum, with a variety of ingenious 
contrivances to keep the vacuum aad 
the steam apart, by variously construct- 
ed valves, some sliding, others turning 
upon.hinges; and in two or three cases 
alternately, revolving pistons have been 
used. I have mentioned these merely to 
shew that my invention differs as widely 
froma them as from the eazine which 
works with a beam and lever; for in.my 
invention, I do not make use of a piston 
which turns round upon the centre or 
axis of its steam vessel, or cylinder, or 
in it, or concentric with it; but my pis- 
tons move in straight lines, like the pis- 
tons of the beam or lever engine, and are 
at the same time carried with their cylin- 
ders round upon, or in a vertical wheel, 
which they partly constitute, and which 
operates as a regulating or fly-wheel ; the 
pistons theréby acquire a compound mo- 
tion, participating of the rectilineal and 
the rotative, which describe a curve, 
yarying with the speed of the engine, 
The appli- 
cation of the expansive force of steam, 
and the power obtained by its condensa- 
tion, are not new; nor do [ attempt to 
innovate permanent principles, but hinge 
my claim solely upon the peculiar man- 
ner of making, arranging, and combining 
the parts, so as to form and make, and 
which have formed and made, a com- 
plete, simple, and effective engine or 
engines, by which the power obtained 
from steam, both by expansion and con- 
densation, is communicated to machinery 
at a-comparatively small expense, and 
with some advantage in the saving of 
fuel? 2.4 
In Mr. Witty’s observations on his 
own invention, compared with those of ° 
others, he says, ‘* J have found, and 
doubt not others have also proved, 
that pistens-move with greater facility. 
Patents tately Enrolled. 
_pistons on the rotative principle. 
[Sept. 1, 
and much tighter, on a straight line in a 
cylinder than in any other direction 
whatever; consequenily, lighter packing 
makes them steam-tight. The operation 
of re-packing, or screwing it down, 1s 
certainly more easy to perform ; and they 
are less liable to get out of order than 
These 
qualities of the cylinder have operated 
to render it the only fit apparatus for 
pneumefic experiments. Whether for 
exhaustion or condensation, nothing but: 
a cylinder with a piston moving in @ 
direct line, has been found to answer for 
so nice a purpose. To the double recis 
procating beam or lever engine my 10- 
venticn 1s, some way analogous; Inas- 
much as it possesses similarity in cylin-_ 
ders, and pistons acted upon by steam 
pressing them upon a vacuum. But the 
manner of disposing, filling, and exhaust- 
ing those cylinders, and of applying the 
power in a circular direction, are the pe= 
culiar properties of my improvement. 
From this combimation, all of what may; 
be called the moving effective apparatus, 
turns round upon one common centres 
and constitutes a fly-wheel. Hence a 
great diminution of friction is the natural 
inference; and, I can safely assert, 1£ 
agrees with my practice. By this me- 
thod of hanging the cylinder upon the fiy- 
wheel, my engine has at once the advan- 
tages of the rectilineal and the rotative, © 
and approaches towards a minimum of 
the disadvantages of both. The exten- 
siveness of the application of steam as an. 
agent of power, renders it impossible to 
prescribe the best manner in which all 
the variety of machinery should be con- 
nected with it. Where pumps are want~ _ 
ed to be worked, I find it convenient ta 
hang their rods upon the reciprocating 
rods of the engine. Frum the same pin 
T also, where required, give motion to a 
wheel twice the speed of the engine. 
But as speed and power can be regulated 
and adapted by various methods, the 
application may almost be deemed arbi- 
trary, and therefore unnecessarily obtru- 
ded, or at least not indispensably the subs 
ject of much observation,” 
MR. WILLIAM DOCKSEY’S (BRISTOL), fo# 
Improvements in the Process of Manu- 
facturing Ivory Bluck, and for redus ; 
cing other Articles to an wmpalpable - 
Powder, aye . 
This invention consists in manufactu- 
ring ivory-black, and all articles capable 
of an easy separation of their parts, by 
calcination, &c. such as potter’s clays, 
\ » flints 
