The solution is filtered from the insoluble residue and saturated with hydrosulphuric acid; sulphur and a trace of copper are deposited. The solution is oxidized, and the iron precipitated as sulphide, which is, however, partly soluble in presence of phosphoric acid.

The phosphoric acid is estimated by fusing the mineral with carbonate of soda, and precipitating it by magnesia.

Nickel, cobalt, and manganese are precipitated by sulphide of ammonium, the iron in this case being separated by carbonate of baryta. The nickel and cobalt may be separated by Liebig's method, or by precipitating the cobalt, by means of carbonate of baryta, from a solution which has been previously treated with chlorine or bromine. The residue is levigated, by which is obtained a black flocculent matter and a black shining substance. The former dissolves in hydrochloric acid, evolving hydrosulphuric acid. The black shining mass dissolves completely in warm nitro-hydrochloric acid; the solution is mixed with soda and carbonate of potassa, and evaporated to dryness, and fused, to remove phosphoric acid. Iron and nickel are determined as above. This is the method which was used by Muller in the analysis of some specimens of meteoric iron from Zacatecas, in Mexico.

GLOSSARY.

Air-condenser.-Is a condenser where air is the cooling medium, steam being contained within the vessel, which may be of tubes or flat plates, around which a current of air circulates.

Air-jackets. Are air spaces left around steam-cylinders and boilers to prevent the dispersion of heat.

Air-pumps.-Are pumps used to remove the air, vapor, and water from the condensers of steam-engines.

Air-vessels. Are fixed upon the discharge-pipes of force-pumps to equalize the pressure of water, and to prevent the occurrence of shocks. Argillaceous.-Clayey.

Ball-valve.-A valve formed by a sphere fitting a spherical seat.

Balance levers.-Are weighted levers used to open the valves of Cornish and other pumping-engines.

Belly. The central part of a blast-furnace.

Bevel-wheels.-Tooth-wheels, having their teeth at an angle to the axis.

Bell-crank.-A lever, having its arms at right angles.

Bilge-pumps.-Are used for removing the bilge-water in ships.

Blast-furnace.-An upright furnace used for smelting iron.

Blooms.-Masses of wrought-iron, as furnished from the puddling-forges.
Blow-holes.-Air spaces which sometimes occur in castings.

Blowthrough Cocks.-Are applied to steam-engines to allow steam to be blown through cylinder and condenser before starting.

Body. The upper part of the blast-furnace.

Boring-bars.-Carry the tools by which cylinders are bored.

Boring-heads. Short cylinders, which carry cutting-tools, and are placed upon boring-bars.

Boshes.-Lower part of the blast-furnace.

Boss.-Circular elevations to receive the pressure of nuts, bolt-heads, &c.; also central projections, to which the arms of the wheels, &c., are attached. Botryoidal.-A term applied to minerals, of which the fracture is conchoidal. Brine-pumps.-Are used to discharge salt-water from marine boilers, at intervals, to prevent super-saturation and deposition of salt.

Broaches.-Tools for smoothing cylindrical or conical holes.

Buckets. Pistons fitted with valves to allow of the passage of fluid through them in one direction.

Bucket-pumps.-Pumps furnished with buckets.
Buddles.-Apparatus for washing minerals.

Cams.-Discs upon which bosses or protusions are formed, either upon the periphery or the face.

Carbonates.-Compounds of earth or oxides with carbonic acid.

Carrier. A piece of apparatus used to secure the revolution of work in a

lathe.

Cataract. A species of brake, which is used to govern the velocity of Cornish pumping-engines.

Centre-punch.-A pointed punch used to mark out work.

Chucks.-Apparatus connected with turning lathes, to which the work to be operated upon is secured.

Clack-valve.-A valve opening on a hinge placed at one edge.
Clinkers.-Slags or scoria which form in furnaces

Clothing. Covering applied to steam-boilers, cylinders, &c., to prevent loss of heat.

Collar-bolt.-A bolt forged with a shoulder cr collar.

Cotter-joint, Gib, and.—A joint made with a key and wedge.

Counter. An instrument for recording the number of strokes or revolutions made by machinery.

Cores.-Pieces of baked earth, used to produce cavities in castings.

Core-prints.-Projections on patterns left to form recesses in moulds, in which to rest cores.

Cross-heads.-Cross-beams carried at the upper ends of piston and other rods.
Cross-tails. Similar to cross-heads, but fixed at the lower extremities of rods.
Cupola.-A small blast furnace, used to melt iron for castings.
Cyanogen. A gas consisting of carbon and hydrogen.

Cylinder ports.-The steam-passages through which steam is admitted to the working cylinder of an engine.

Deoxidation.-Removal of oxygen from bodies with which it is combined.
Detent.-A catch to arrest the teeth of wheels or racks. ́

Dividing-engine.-A. machine to effect the graduation of scales.
Disengaging-gear.-Gear for stopping and starting engines.
Donkey-engines.-Small engines used to feed steam-boilers.
Double-beat valves.-Valves formed with two seatings.
Drifts.-Tools used to clear square and polygonal holes.
Dynamics.-The science which treats of the motion of bodies.

Eccentric.-A wheel fixed eccentrically upon a shaft to produce rectilineal

from rotative motion.

Eccentric strap.-A band surrounding the eccentric, and within which the eccentric revolves.

Equilibrium-valve.—A valve so formed that it is unaffected by fluid pressure in either direction.

Exhaust port.-The opening by which waste steam leaves the working cylinder. Expansion-valve.-A valve used to cut off the supply of steam at any pcsition of the engine.

False seams.-Ridges produced on castings where the mould is joined.
Feed-pump.-A pump used to supply steam-boilers.

Ferruginous.-Containing iron.

Flasks.-Boxes in which moulds for castings are made.

Fluxes.-Materials used to dissolve scoriæ and protect surfaces from oxida

tion.

Fly-wheel.-A heavy wheel employed to equalize the motion of machinery. Floats. A kind of file, but having redges instead of teeth.

Gab-lever.-An eccentric rod having a gap to embrace the valve-gear

Galena.-A combination of sulphur and lead.

Gates or Gits.-Air and feed-holes left in moulds for castings.

Gauge-cocks.-Cocks fixed at various levels in a steam-boiler to show the height of the water level.

Gauge-glass.-A glass tube connected at top and bottom with the boiler to show the water level at sight.

Gib and Cotter-joint.-See Cotter.

Gits.-See Gates.

Gland. The cover of a stuffing-box.

Governor.-An instrument to regulate the motion of a prime mover. Grease-cock.-A cock to allow of the entrance of grease to steam-cylinders, &c., without loss of steam.

Gudgeons.-Short shafts, pins, or studs acting as axes of rotation or oscillation.

Heads. The standards which carry the centres of a lathe.

Heads-boring.-See Boring-heads.

Heads-cross.-See Cross-heads.

Hearts.-The vessels making the communications between the various tubes of Craddock's boiler.

Heat, latent.-Heat which has disappeared during liquefaction or gasification. Heats, specific. The relative quantities of heat contained by various bodies of equal weight.

Hob.—A kind of screw used to make dies and screw-cutting tools-
Hub.-See Boss.

Hom genity.-Uniformity of texture and constitution.

Horn-plates -The plates which guide and retain the axle-boxes of railway

and other vehicles.

Horse-power.-One horse-power is equal to 33,000 foot-pounds of work per minute.

Hot well.-A cistern into which the water, &c., from the condenser of a steamengine is raised by the air-pump.

Indicator.-An instrument for determining the pressure in the cylinder of a

steam-engine.

Injector, Gifford's.-An instrument for feeding boilers by means of a jet of

steam.

Injection-cock.—The cock which regulates the admission of water to the condenser.

Jigging.-Washing minerals in a sieve.

Journal. That part of a shaft which is in contact with the bearings.

Joule's equivalent. The amount of work found by Dr. Joule to be equivalent to one unit of heat, the work being expended in the production of friction, 772 foot-pounds.

Junk rings.-The rings by which piston packings are retained in position and tightened-up when necessary.

Leading screw.-That screw by which the slide-rest of a screw-cutting lathe is caused to progress along the lathe bed.

Latent heat.-See Heat, latent.

Mandril.-The shafts in the head-stock of a lathe which carries the centre.

Manhole.-An opening in a steam-boiler to admit a man to clean it.

Matrix. The soil surrounding a mineral which adheres to it when it is ex

cavated.

Mitre wheels.-Bevel wheels, having their teeth at an angle of 45° to the axis. Moment of force.-The intensity of a rotating force, multiplied by its distance from the centre of rotation.

Mud-hole.-An aperture in the lower part of the boiler to allow the sediment to be washed out.

Nozzles. The extremities of the steam and exhaust passages of the cylinder of a steam-engine.

Oxidation. The combination of oxygen with any substance.
Oxides.-Compounds of oxygen with various bodies.

Packing.-Metal, india-rubber, or hemp, employed to prevent the escape of steam past the moving parts of an engine.

Pull.-See Detent.

Plug-rod.-Rod by which the valve-gear of a pumping-engine is wrought.
Plummer-blocks.—Carry the bearings of shafts.

Poppet-head.-The back head of a lathe.

Ports.-See Cylinder ports.

Power-Work divided by time.

Prints. See Core prints.

Pump buckets.-See Buckets.

Reniform.—Of a kidney shape.

Rhymers.-See Broaches.

Riggers.-Pulleys by which motion is transmitted through bands.
Ring-valves.-Double-beat valves, having the two beats in the same plane.

Roasting. An operation to remove sulphur, arsenic, and other volatile ingredients from minerals to be smelted.

Scabs.-Defects on castings produced by the peeling of the mould.
Shank.-A large ladle used by moulders.

Silicates.-Combinations of silicic acid with various bases.

Slag or Scoria.-The refuse from smelting operations.
Snap.-A swage used for forging the heads of rivets.

Snugs.-Projections to afford means of attachment or to fix the position of plummer blocks, &c.

Spur wheels.-Tooth wheels.

Spring beams.-Stout beams that receive the blow at the termination of the stroke of a Cornish engine.