Part 180

In proving geographical propositions, we are to observe, that several properties, and chiefly the celestial, are confirmed by proper demonstrations; being either grounded on experience and observation, or on the testimony of our senses: nor can they be proved by any other means. There are also several propositions proved, or rather exposed to view, by the terrestrial globe, or by geographical maps.

Other propositions cannot be so well proved, yet are received as apparent truths. Thus, though we suppose all places on the globe, and in maps, to be laid down in the same order as they are really on the earth; nevertheless, in these matters, we rather follow the descriptions that are given by geographical writers.

GEOGRAPHY is very ancient, at least the special part thereof; for the ancients scarce went beyond the description of countries. It was a constant custom among the Romans, after they had conquered or subdued any province, to have a map or printed representation thereof, carried in triumph and exposed to the view of the spectators. Historians relate that the Roman senate, about 100 years before Christ, sent geographers into divers parts to make an exact survey and mensuration of the whole globe; but they scarcely ever saw the 20th part of it.

Before them, Necho, king of Egypt, ordered the Phœnicians to make a survey of the whole coast of Africa, which they accomplished in 3 years. Darius procured the Ethiopic sea, and the mouth of the Indus, to be surveyed; and Pliny relates, that Alexander, in his expedition into Asia, took two geographers to measure and describe the roads; and that from their itineraries, the writers of the following ages took many particulars. Indeed this may be observed, that whereas most other arts and sciences are sufferers by war, geography, artillery, mining, and fortification, alone have been improved thereby. Geography, however, must have been exceedingly defective, as a great part of the globe was then unknown, particularly all America, the northern parts of Europe and Asia, with the Australasia, and Magellanica; and they were also ignorant of the earth’s being capable to be sailed round, and of the torrid zone being habitable, &c.

The honor of reducing geography to art and system, was reserved for Ptolemy; who, by adding mathematical advantages to the historical method in which it had been treated of before, has described the world in a much more intelligible manner: he has delineated it under more certain rules, and by fixing the bounds of places from longitude and latitude, has discovered other mistakes, and has left us a method of discovering his own.

GEOLIER des prisons militaires, Fr. the superintendant or head jailor of military prisons. Under the old French government, this person had a right to visit all prisoners that were not confined in dungeons. He could order provisions, wood, and coal to be conveyed to them; but he had not the power of permitting women to visit or have any intercourse with the soldiers; and when their period of imprisonment expired, he could not detain them on account of debts contracted for food, lodging, or fees, &c. Half of the prisoner’s subsistence for one day, according to his rank, was given on his release.

GEOMETRICAL elevations, just dimensions of ascent proportionate to a given scale, &c. See ORTHOGRAPHY.

GEOMETRIE, Fr. Geometry.

GEOMETRIE composée, Fr. compound geometry, which consists in the knowlege of curved lines, and of the different bodies produced by them. The immediate object or intent of compound geometry is confined to conic sections, and to lines of that species.

GEOMETRIE sublime et transcendante, Fr. these terms have been applied by the French to the new system of geometry, which was produced by Leibnitz, and Newton, when they found out the method of calculating ad infinitum.

GEOMETRY, originally signified no more than the art of measuring the earth, or any distance or dimensions in it; but at present it denotes the science of magnitude in general; comprehending the doctrine and relations of whatever is susceptible of augmentation or diminution, considered in that light. Hence, to geometry may be referred the consideration not only of lines, surfaces, and solids; but also of time, velocity, number, weight, &c.

Plato thought the word geometry an improper name for this science, and accordingly substituted in its place the more extensive one of mensuration; and after him, others gave it the name of pantometry, as demonstrating not only the quantities of all manner of magnitudes, but also their qualities, ratios, positions, transformations, relations, &c. and Proclus calls it the knowlege of magnitudes and figures, and their limitations; also of their motions and affections of every kind.

Origin and progress of GEOMETRY. This science had its rise in Asia, the invention, which at first consisted only in measuring the lands, that every person might have what belonged to him, was called geometry, or the art of measuring land; and it is probable, that the draughts and schemes which they were annually compelled to make, helped them to discover many excellent properties of these figures; which speculation has continued gradually to improve to this day.

From Asia it passed into Egypt, and thence into Greece, where it continued to receive improvement from Thales, Pythagoras, Archimedes, Euclid, &c. The elements of geometry, written by Euclid in 15 books, are a most convincing proof to what perfection this science was carried among the ancients. However, it must be acknowleged, that it fell short of modern geometry, the bounds of which, by the inventions of fluxions, and the discovery of the almost infinite order of curves are greatly enlarged.

Division of GEOMETRY. This science is usually distinguished into elementary, and higher or sublime geometry. The first, or elementary geometry, treats of the properties of right lines, and of the circle, together with the figures and solids formed by them. The doctrine of lines comes first, then that of surfaces, and lastly that of solids. The higher geometry comprehends the doctrine of conic sections, and numerous other curves.

Speculative and practical GEOMETRY. The former treats of the properties of lines and figures, as Euclid’s Elements, Apollonius’s Conic Sections, &c. and the latter shews how to apply these speculations to the use of mensuration, navigation, surveying, taking heights and distances, gauging, fortification, gunnery, &c.

Usefulness of GEOMETRY. Its usefulness extends to almost every art and science. By the help of it, astronomers turn their observations to advantage: regulate the duration of times, seasons, years, cycles, and epochs; and measure the distance, motion, and magnitudes of the heavenly bodies. By it geographers determine the figure and magnitude of the whole earth; and delineate the extent and bearings of kingdoms, provinces, harbors, &c. It is from this science also that architects derive their just measure and construction of public edifices, as well as of private houses.

It is by the assistance of geometry that engineers conduct all their works, take the situation and plans of towns, the distances of places, and the measure of such things as are only accessible to the sight. It is not only an introduction to fortification, but highly necessary to mechanics. On geometry likewise depends the theory of gunnery, mining, music, optics, perspective, drawing, mechanics, hydraulics, pneumatics, &c.

We may distinguish the progress of geometry into three ages; the first of which was in its meridian glory at the time when Euclid’s Elements appeared; the second beginning with Archimedes, reaches to the time of Descartes; who by applying algebra to the elements of geometry, gave a new turn to this science, which has been carried to its utmost perfection by our learned countryman Sir Isaac Newton, and by the German philosopher Leibnitz.

GEORGE, or knight of St. George, has been the denomination of several military orders. See GARTER.

GERBE, Fr. means literally a sheaf, but it here signifies a sort of artificial firework, which is placed in a perpendicular manner, and resembles a sheaf. See JETS de feu.

GERBE likewise means the tithe which was formerly paid to the French curates.

Faire GERBE de foarre à dieu, Fr. a figurative expression, signifying, that the farmer made up the worst sheaf he could for the parson; filling it principally with straw instead of good ears of corn.

GERMS, small coasting vessels employed by the French, to keep up an intercourse with Egypt.

GESE, Fr. a weapon used in former times.

GESES and Materes were adopted by the Allobroges (a body of ancient Gauls so called) independently of the broad cut and thrust sword, which the Swiss still wear. These instruments were only one cubit long; half the blade was nearly square, but it terminated in a round point that was exceedingly sharp. Virgil in his Æneid calls this species of blade, alpin, meaning, no doubt, to convey, that it was in general use among the neighboring inhabitants of the Alps. Not only the Romans, but the Greeks received it into their armies. The former retained the full appellation and called it gése, but the latter corrupted it into ysse. This is the only weapon with which those soldiers were armed that escorted malefactors, who were condemned to death, to the place of execution. The term gese was also applied to a sort of a javelin.

GESSATES, a people of whom Polybius speaks in his history of the ancient Gauls, and who inhabited the countries lying adjacent to the alps, and to the river Rhone. According to some writers, they were so called because they constantly wore geses. The gese is said to have been a dart which the ancient Gauls exclusively used, and which some authors since confounded with the pertuisane or partisan, a sort of halbert, called by others a javelin. This word was used in Provence, as late as the year 1300; for in the inventory which was taken of the goods, furniture, &c. appertaining to the Templars, we find gessus or gesus particularly specified in the list of weapons and iron instruments, which was understood to mean gese, and under that appellation was deposited in the king’s archives at Aix. See BOUCHER, Hist. Prov. Liv. ii. c. 4. p. 82. This same author further asserts, that the Gési, and the Gessates took their names from that weapon. He quotes Julius Cæsar’s account of the word gesi in confirmation of his own opinion. Many authors have mentioned the same term: among others, Justus, Lipsus, Hugo, Cheves, Vossius, &c.

GESSATE ou GESATE, Fr. a knight among the ancient Gauls, who took delight in war, and frequently volunteered his services beyond the boundaries of his native country. Whenever a neighboring country made a levy of men, it was usual for the gessates to accompany the troops, from a conviction that it would be dishonorable in them to remain inactive at home. These adventurers, or knights-errant, were called gessates, either on account of the gessus or large dart, which they carried, or, as Polybius imagines, on account of the subsistence which was paid them, and was called by that name.