GARDEN ENGINES. The engines em ployed for watering plants in gardens are very similar in principle to fire-engines. The water is either poured into them from buckets, or drawn in by a suction-pump ; while it is ex pelled in a continuous stream by a forcing pump, easily worked by one or two handles.
At the various agricultural and cattle shows, garden-engines are usually exhibited among other apparatus. One such, exhibited at the Smithfield cattle show in 1850, is placed on a light platform drawn on four low wheels ; it is worked by six men, and will discharge CO gallons per minute; it is therefore fitted to act as a fire-engine, and as a garden-engine on a large scale. Read's patent garden-engine has two wheels and two handles ; it will con tain 28 gallons, and a jet can be forced by one man to a distance of 50 feet; it is adapted for watering both wall trees and standard plants. A slight modification in an instrument of this kind renders it workable by two men, with a power to force a large stream of water on any distant object. Mr. Warner has lately regis tered an ingenious spreader, by which the jet from a garden-engine can be readily spread out into a fan-like form. The same inventor has introduced a ' fire-engine, force pump, drainer, and irrigator,' for farming purposes. It consists of an engine supported by a kind of barrow with two wheels and two handles; it can be worked by one or two men ; it draws in its own water from a tank or reservoir, and it forces out a stream of considerable power. GARNET. There are many varieties of this well-known precious stone. Some of them are probably distinct species ; but, agree ing in form and some other properties, they are classed together. This mineral occurs crystallised, massive, and granular. The primary form is a cnbe, but it occurs in the form of a rhombic dodecahedron. The erys. talline varieties, according generally to their colour, have received various names. Praious garnet, Alnzandine ; black, Melanite ; Pyre mite; greenish yellow, Grossularia ; yellow, crystallised, Topazolite; granular, Succinite; brownish yellow, granular, Colophonite ; green ish, compact, Allochroite ; red, Pyrope, Car buncle; reddish brown, Essonite, Cinnamon stone, Romanzovite; magnesian, Rothoffite.
• GARONNE. The mineral treasures of this French department are iron,, copper, lead, an timony, bismuth, zinc, coal, rock-crystal, slates, gypsum, marble, jet, and granite. Gold is found in the sands of the Garonne and the Salat. There is a salt-spring at Sa lies. Mineral waters are found at various places ; those of Bagneres-de-Luchon are the most celebrated.
The quantity of wine grown in the depart ment annuallyis 14 to 15 million gallons, one third of which is used for home consumption ; the quality is generally inferior. The com merce of the department is composed of its agricultural products and of its manufactures, the chief of which are scythes, files, copper utensils, mathematical instruments, porcelain, pottery, tiles, coarse woollens, canvas, blankets,1 calico, tape, brandy, tin-ware, and leather various kinds. There are about 80 iron fur naces, and about 350 factories of different kinds, including glass works, copper foundries, cannon foundries, gunpowder mills, tobacco factories, distilleries, marble sawing works, &e. ; together with more than 1000 wind and water mills. The department has considerable commercial intercourse with Spain, whither many handicraftsmen annually emigrate to exercise their callings.
The commerce and industry of the chief town, TOULOUSE, are briefly noticed else where.
GAS. The main difference between vapours and gases is, that vapours are reduced to solids or liquids when the heat is withdrawn ; while gases preserve their aeriform state at common temperatures. This difference is one of de gree only, but it is usefully retained. The number of gaseous bodies is great, and they possess in many respects such different pro. perties that it would be impossible to give a general description of them.