/ 
STE 
by four-sided pyramids, intersecting each 
other at right angles ; the plane of intersec- 
tion passing longitudinally through the prism. 
Sometimes these prisms occur solitary. Pri- 
mitive form, an octahedron with isosceles 
triangular faces. The faces of the crystals 
striated longitudinally. Its texture is foli- 
ated. Its lustre glassy. Specific gravity 
2.3. Colour milk-white. When heated 
slowly, it loses 0.15 or 0.16 parts of its 
weight, and falls into powder. It efferves- 
ces with borax and microcosmic salt, and is 
reduced to a greenish opaque mass. With 
soda it melts into a frothy white enamel. 
When its powder is thrown on a hot coal, it 
emits a greenish yellow light. The con- 
stituent parts are 
Silica 44 
Alumina 20 
Barytes 20 
Water 16 
100 
STAY, in the sea language, a big strong 
rope fastened to the top of one mast, and 
to the foot of that next before it, towards 
the prow-, serving to keep it firm, and pre- 
vent its falling aftwards, or towards the 
poop. Alt masts, top-masts, and flag staves, 
have their stays, except the sprit-sail top- 
masts. That of the main-mast is called the 
main-stay. The main-mast, fore-mast, and 
those belonging to them, have also back- 
stays to prevent their pitching forwards, or 
over-board, as going on either side of her. 
To stay a ship, or to bring her on the stays, 
is to manage her tackle and sails so that she 
cannot make any way forwards ; which is 
done in order to her tacking about. 
STEALING, the fraudulent taking away 
of another man’s goods, with an intent to 
steal them, against, or without tlie will of 
him whose goods they are. This is punish- 
ed, according to circumstances, very differ- 
ently by the English laws. A late statute, 
1808, has altered the punishment for pri- 
vately stealing from the person, or picking 
pockets, which was a capital felony, and has 
made it a simple larceny, subject to trans- 
portation only. See Burglary, Larceny, 
Robbery. 
STEAM Engine, an engine for raising 
water, or for producing any powerful effect 
in moving machinery, &c. by the force of 
steam obtained from boiling water. It is 
often called a fire-engine, on account, 
perhaps, of the fire employed in heating 
STE 
the water, in order to throw off the steam. 
This is unquestionably one of»the most use- 
ful, curious, and important maciiines that 
has ever been invented ; and it is thought, 
that without tlie aid of this, or some other 
engine adapted to the same purpose, we 
should long ere this have been deprived of 
the benefit of coal fires ; as our forefathers, 
full a century ago, had excavated almost 
all the mines of that substance as deep as 
they could be worked, without the aid of 
some engine to draw water from greater 
depths. The principle of this machine is as 
follows: there is a forcing pump with its 
rod fixed to one end of a lever, which is 
worked by the weight or pressure of the 
atmosphere upon a piston at the other end, 
a temporary vacuum being made below it, 
by suddenly condensing the steam, that had 
been let into the cylinder in which this pis- 
ton works, by a jet of cold water thrown 
into it. A partial vacuum being thus made, 
the weight of the atmosphere presses down 
the piston, and raises the other end of the 
straight lever with water, &c. from the 
mine. Then immediately a hole is unco- 
vered in the bottom of ,the cylinder, by 
which a fresh supply of hot steam rushes in 
from the boiler, which acts as a counter- 
balance for the atmosphere above the pis- 
ton, and the weight of the pump rods at the 
other end of the lever carries that end 
down, and of course raises the piston of the 
steam cylinder. The orifice for the emission 
of the steam is immediately shut, and the 
cock opened for injecting the cold water 
into the cylinder : this condenses it to wa- 
ter, and another vacuum is made below the 
piston, which is now again forced down by 
the weight of the atmosphere, and thus the 
work is continued so long as water and fuel 
are supplied. *• 
This is the common principle of the steam 
engine, but the methods of operation are 
very various : there is seldom a year that 
passes away, that we have not new patents 
obtained for improvements, or professed 
improvements, of this machine. It is com- 
paratively of modern invention: the ear- 
liest account of any one is that in the Mar- 
quis of Worcester’s History of Inventions, 
published in the year 1663 ; the description 
here is too scanty to work upon, hut it fur- 
nished the idea, which has afforded to inge- 
nious men of all nations the opportunity of 
putting forth their skill, and their talents, 
in executing a number of important im- 
provements on the subject. Captain Sa- 
very was the first person who attempted to 
