the graduated scale affixed to one of their arms and a vernier in connexion with the other. A V-gauge, which, instead of a series of notches round its edge, has only one long tapering notch, by the graduations of which the diameter of any wire that will enter it can be read off, is simple and tolerably efficient. So also is the kindred arrangement (fin. 5), in which a wire or plate can be inserted between a fixed pin and the edge of a revolving cam with graduated face. But perhaps on the whole the best and handiest form is the Micrometer Gauge (fig. 2), which, by means of a micrometer screw with a divided head, measures to the one-thousandth part of an inch, and in careful hands can render visible even smaller fractions. Gauges consisting of two arms jointed together like pincers are also used in certain trades, minute differences in the width of the jaws being magnified and rendered visible on
a graduated are at the opposite ends of the arms.For special purposes gauges of many other forms are employed, some of which are of much greater delicacy, but these cannot be described here. The only others which remain to be mentioned are those of which the Plug and Collar Gauges (fig. 4) are the type, sets of which are now to be found in almost all mechanical workshops where the value of standard dimensions is recognized. Each gives only the one external or internal dimension for which it is made, but it gives that with the highest attainable accuracy, so that by carefully preserving a comparatively small num- ber of these for reference, and using them in conjunction with measuring machines,- the most minute differences can be measured and noted in terms of the standard, so that exact sizes can at any future time be again obtained with- out appreciable error.
GAUHÁTI, a town in Kámrúp district, Assam, the chief town of the province, situated on the left or south bank of the Brahmaputra, lat. 26° 11' 18" N., long. 91° 47' 26" E. Gauhati, which is the most populous town in the Brahmaputra valley, was the seat of the British administra- tion of Assam up to 1874, when the headquarters were removed to Shillong in the Khasi bills, 67 miles distant, with which it is connected by an excellent cart road. Gauhata is an important centre of river trade, and the largest seat of commerce in Assam. A regiment of native infantry is permanently cantoned there. Two much fre- quented places of Hindu pilgrimage are situated in the immediate vicinity, the temple of Kamakhya on a hill 2 miles west of the town, and the rocky island of Umananda in the mid-channel of the Brahmaputra. Population (1872), 11,492; municipal revenue, £2727.
GAUL, the name given by the Romans to the country lying between the Rhine and the Pyrenees. When the Greeks first became acquainted with the south-west of Europe they applied to the whole of it, in a somewhat vague sense, the term Celtice KeA-rmfi), calling its inhabitants Celts (Kc/\Tor’). Later we find Galatia (I‘aAa-n’a) and Gallia (I‘aAMa), with the corresponding Galati (I‘aAc’L-ror) and Galli ( I‘dAAor), used as nearly synonymous with the earlier name. The shorter of these two forms the Romans adopted; and in the opening chapter of Caesar’s well-known Commentaries, we have our first definite account of the limits of the country and its divisions, as then understood. According to this authority, alaul was in his day divided among three peoples, more or less distinct from one another, the Aquitani, the Gauls, who called themselves Celts, and the Belgae. The first of these extended from the Pyrenees to the Garumna (Garonne) ; the second from that river to the Sequana(Seine) and its chief tributary the Matrona (Marne), reaching eastward presumably as far as the Rhenus (Rhine); and the third from this bounding line to the mouth of the last-named river, thus bordering on the Germans. By implication Caesar recognizes a fourth division, the Provincia, lying to the south in the basin of the Rhodanus (Rhone), and stretching westwards as far as Tolosa (Toulouse) in the basin of the Garonne—a portion of Gaul that had been subdued and made a Roman province about fifty years before Caesar entered on his career of conquest there. By far the greater part of the country was a plain watered by numerous rivers, 'the chief of which have already been mentioned, with the exception of its great central stream, the Liger or Ligeris (Loire). Its principal mountain ranges were Gebenna or Gebenna (Cevennes) in the south, and J ura, with its continuation Vosegus or Vogesus (Vosges), in the east. The tribes inhabiting Gaul in Caesar’s time, and belonging to one or other of the three races distinguished by him, were numerous. Prominent among them, and dwelling in the division occupied by the Celts, were the Helvetii, the Sequani, and the fEdui, in the basins of the Rhodanus and its tributary the Arar (Safme), who, he says, were reckoned the three most powerful nations in all Gaul ; the Arverni in the mountains of Cebenna ; the Senones and Carnutes in the basin of the Liger; the Veneti and other American tribes between the mouths of the Liger and Sequana. The Nervii, Bellovaci, Suessiones, Remi, Morini, Menapii, and Aduatici were Belgic tribes ; the Tarbelli and others were Aquitani; while the Allobroges inhabited the north of the Provincia, having been conquered in 121 b.c.
The ethnological relations of Caesar’s three great Gallic races have given rise to much discussion. Greek writers, who, in consequence of the planting of the colony of Massilia (Marseilles) on its southern coast at so early a period as 600 b.c., had gained some knowledge of Gaul before the Romans, speak of its inhabitants as Ligurians; and it is certain that a people of this name occupied at one time the coast-line of Europe from the western slopes of the maritime Alps to the Rhone. By many these Ligurians are regarded as having once spread themselves over a much wider area, peopling extensive tracts of Europe as well as Northern Africa. Subsequently, another race, coming probably across the Pyrenees from Spain, subdued south-western Gaul and ruled as far north as the Garonne—the Basques of the two slopes of these mountains remaining to our own day their lineal represen- tatives. Later still, but at a date which history does not venture to fix, one of those great waves of population that are believed to have rolled in succession from east to west brought into northern and central Gaul, it may be at an interval of centuries, the two great branches of the Celtic race, the Gadhelic or Gaelic and the Cymric—the one represented in Britain by the Irish and Scottish Highlanders, the other by the Welsh. Reading Caesar’s brief statements by the light thus afforded, etlmologists now generally hold that his Aquitani were Iberians, largely intermingled with intrusive Gauls; that his Gauls belonged to the Gaelic division of the Celtic race, and his Belgae to the Cymric (both of them, however, being affected by the presence of races whose territory they had overrun, and the latter by the addition of a German element derived from their prox- imity to the Rhine); and that the natives of the Provincia were Ligurians, with so large an intermixture of Celts as to make the latter the dominant race. Neither the Greek colony of Massilia, nor these colonies sent out by it, can be supposed to have seriously affected the Gaulish nation from the point of view we are now discussing. It was in a different manner, as a civilizing agency, that they made their presence felt.
made a part of the Roman empire by Julius Caesar shortly before the commencement of the Christian era; and, as has often been remarked, such in the main it is still. Some
recent scientific inquirers find grounds, however, for con-