lishments provided for the reception of goods or passengers or crew, and where such purifying processes as the sanitary science of the time prescribes are applied. Until a ship is discharged from quarantine, she-displays a yellow flag at her masthead if she has a clean bill of health, a yellow flag with a bl. ck spot if not clean ; at night a white light is shown at the same place. The permit to hold intercourse after performing quarantine is called pratique. Quarantine is not of necessity limited to a sea-frontier; it is enforced at the frontiers between adjacent states, and by cities and towns on houses in which are cr.ses of infectious diseases.

Quar'rying is excavating stone, which may be done either by hand or by dynamite, blasting powder or other explosiv. s. The art demands intimate knowledge of the structure of the rock to be excavated. This rock is commonly of one of two kinds, either stratified or igneous. The most important stratified rocks for quarrying are limestone and sandstone. The quarryman takes advantage of the bedding and natural cleavage of these rocks, so as to direct his efforts along the line of least resistance. Even some of the hardest of the igneous rocks, gr nite for example, have natural lines of cleavage, which may be utilized. The stratified rocks are split by means of a plug fi. ed in a hole in the rock between two wedges, known as "feathers." When the plug is hammered, the wedges operate on the stone with a great splitting force. This method, however, is only applicable to blocks of a limited size. Explosives, as dynamite and gunpowder, will loosen blocks of the largest description. Dynamite shatters the rock to such a degree that it is more serviceable in quarrying road-stone than building-stone. Sometimes a large block is cut off by a channeling machine, which cuts by means of a sharpened bar impelled by steam-power. When quarried, the stone is cut and dressed for use in building, statuary etc.

Qua'-'termas'ter, an officer whose duty is to provide quarter, provisions, storage, clothing, fuel, stationery and transportation for the army and to superintend the supplies. In the navy the quartermaster is a petty officer who attends to the helm, binnacle, signals and the like under the direction of the master.

Quartet', a piece of music arranged for four solo voices or instruments, in which all the parts are obligato — that is, no one can be omitted without injuring the proper effect of the composition. A mere interchange of melody, by which the parts become in turn principal and subordinate, without the interweaving of them, does not constitute a quartet. Quartets for stringed instruments are generally arranged for two violins, a viola and a violoncello,

and are sonata in form — that is, have a progression of thought and movement. They originated with Haydn, and were further developed by Mozart and, notably, by Beethoven, who perfected the art of part-writing in music. Subsequent writers are Schubert, Spohr, Mendelssohn, Schumann and Brahms. Vocal quartets were a frequent feature in oratorios and operas up to the time of Wagner.

Quartz (kw'drts), the name of the commonest mineral substance of nature. Chemically, quartz is silicon oxide (Si02). Quartz occurs in nature in the crystalline and the noncrystalline forms. When crystalline, it occurs in six-sided prisms terminated by pyramids. Well-developed crystals are most commonly found in veins or open spaces in rocks. By far the larger part of quartz even that which is really crystalline, does not occur in the form of prisms, but in the form of sand grains, pebbles etc., which themselves were derived from crystals. Quartz is one of the constituent minerals of most light-colored igneous and metamorphic rocks; is the chief constituent of most sandstone; and is an important constituent of most other sorts of sedimentary rock, except limestone. It is the hardest of the common minerals. Pure quartz is transparent, but it often contains impurities which give it distinctive and sometimes beautiful colors. Several varieties of quartz constitute gems, some of them of great value. Here belong amethyst, a transparent, purple variety of quartz; agate, the banded variety of quartz from which cameos are cut; chalcedony, a translucent variety; smoky quartz; cat's eye quartz; jasper, a red, opaque variety", various so-called topazes (not the true topaz) ; rose quartz, a ph kish or rose-tinted variety; and rock crystal, or crystals of pure quartz. Flint and chert are impure varieties of quartz.

Quassia {kwŏsh'-), from the name of a, negro, Quassy or Quash, who prescribed this article as a specific for fevers — a bitter wood obtained from the various trees of the quassia family, all of which are natives of tropical America or the West Indies. The wood and bark are used as medicine. Cabinet-wood made from it is safe from all attacks of insects.

Quebec', Can. This, the oldest province of the Canadian Dominion, entered the federation in 1867. It has Ungava on the north; the Gulf of St. Lawrence on the east; New Brunswick, the United States and Ontario on the south; and Ontario on the west.* Quebec has an area of 347,000 square miles. This equals that of France and Prussia combined, and is nearly three times as large as that of the British Isles.

*Newfoundland governs the coast of Labrador, which cuts off Quebec from the Atlantic.