Q (kū), the seventeenth letter, is a consonant, duplicating k the guttural and being a superfluous character. It is always followed by u, qu having the sound of km as in conquest and queen, except in some words where u is silent, as in antique and coquette.

Quadrant (kwod'rant), an astronomical instrument, invented by Hadley in 1731 for use in measuring angles at sea and in other places where a fixed divided circle is not available. The quadrant, in a crude form, had been used for several hundred years before the time of Hadley, if we admit the astrolabe graduated through 900 as a kind of quadrant. But Hadley so improved the instrument by introducing a fixed and a movable mirror and by bringing into the same line the images of the two objects whose angular distance is to be measured, that he really made a new and highly valuable apparatus. The quadrant is merely a brass frame, provided with a radial arm carrying a mirror, whose polished surface contains the axis of the quadrant. By looking through the small telescope and a half-silvered mirror (attached to the quadrant) at any particular object, one may, by rotating this radial arm, make the image of a second object appear in the same direction as the first. The angle through which t"he arm must be turned to secure this coincidence is half the angle subtended by the two objects; and this angle is read directly from the graduated edge of the quadrant. Sometimes only 6o° of the edge is graduated, in which case the instrument is called a sextant. Hadley's invention immediately displaced the astrolabe and the cross-staff which had hitherto been used for taking latitudes at sea. A considerable part of the accuracy of the quadrant is due to the use of the vernier, invented by Pierre Vernier in 1631. About the same time the telescopic sight was invented by Gascoigne and the tangent screw by Helvelius. All combine to make the quadrant or sextant a thoroughly accurate instrument, now in daily use by all navigators.

Quad'rilat'eral, four fortresses of northern Italy —- Mantua, Verona, Peschiera and Legnano — which form a sort of outwork to the bastion of the mountains of the Tyrol, and divide the plain north of the Po into two sections by a powerful barrier. They have figured in all the later wars fought in northern Italy, especially in the wars between Austria and the different Italian states.

Russia has a similar combination in Poland, called the Polish Quadrilateral.

Quad'ruple Alli'ance, a league against Spain, formed in August, 1718, between Britain, France, Austria and Holland, to counteract the ambitious schemes of Albe-roni. It was made upon the basis of the Triple Alliance, which had been formed in January, 1717, between England, Holland and France, and by which the clauses in the treaty of Utrecht having reference to the accession of the house of Hanover in England, the renunciation by the Spanish king of his claims to the French throne and the accession of the house of Orleans to the French throne, should the young king, Louis XV, die without issue, were guaranteed. The Spanish fleet was destroyed by Byng off Cape Passaro; the French crossed the Pyrenees and defeated the Spaniards several times; and at length Philip was compelled to dismiss Alberoni and accept the terms of the Quadruple Alliance.

Quaestor (kwes'tor) anciently was the title of a class of Roman magistrates, reaching as far back, according to all accounts, as the period of the kings. The oldest quaestors were the quœstores parricidii (investigators of murder, finally public accusers), who numbered two. Their office was to conduct the trial of persons accused of murder and to execute the sentence that might be pronounced. They ceased to exist as early as 366 B. C, when their duties were transferred to the triumviri capitales. But a far more important though later office was the quœstores classici, to whom was intrusted the charge of the public treasury. They seem to have gained the name of classici from their having been elected originally by the centuries. At first there were only two, but in 421 B. C. two more were added. Shortly after the breaking out of the First Punic War the number was increased to eight; and, as province after province was added to the Roman republic, they amounted in the time of Sulla to twenty and in the time of Cęsar to forty. At first only patricians could be quęstors; but after 421 B. C. the office was open to plebeians also.

Quagga (kwag'ga), a striped wild ass, related to the zebra and, like the latter, peculiar to Africa. It formerly abounded in herds on the plains south of Vaal River, but now is rare, if not extinct. During its abundance thousands were killed annually by Boer hunters for their skins. It is easily