GROIN. (1) An obsolete word for the grunting of swine, from Lat. grunnire, and so applied to the snout of a pig; it is probably the origin of the word, more commonly spelled “groyne,” for a small timber framework or wall of masonry used on sea coasts as a breakwater to prevent the encroachment of sand and shingle. (2) (Of uncertain origin; from an older form grynde or grinde; the derivation from “grain,” an obsolete word meaning “fork,” cannot, according to the New English Dictionary, be accepted), in anatomy the folds or grooves formed between the lower part of the abdomen and the thighs, covering the inguinal glands, and so applied in architecture to the angle or “arris” formed by the intersection of two vaults crossing one another, occasionally called by workmen “groin point.” If the vaults are both of the same radius and height, their intersections lie in a vertical plane, in other cases they form winding curves for which it is difficult to provide centering. In early medieval vaulting this was sometimes arranged by a slight alteration in the geometrical curve of the vault, but the problem was not satisfactorily solved until the introduction of the rib which henceforth ruled the vaulting surface of the web or cell (see [Vault]). The name “Welsh groin” or “underpitch” is generally given to the vaulting surface or web where the main longitudinal vault is higher than the cross or transverse vaults; as the transverse rib (of much greater radius than that of the wall rib), projected diagonally in front of the latter, the filling-in or web has to be carried back from the transverse to the wall rib. The term “groin centering” is used where, in groining without ribs, the whole surface is supported by centering during the erection of the vaulting. In ribbed work the stone ribs only are supported by timber ribs during the progress of the work, any light stuff being used while filling in the spandrils. (See [Vault].)
GROLMANN, KARL WILHELM GEORG VON (1777-1843), Prussian soldier, was born in Berlin on the 30th of July 1777. He entered an infantry regiment when scarcely thirteen, became an ensign in 1795, second lieutenant 1797, first lieutenant 1804 and staff-captain in 1805. As a subaltern he had become one of Scharnhorst’s intimates, and he was distinguished for his energetic and fearless character before the war of 1806, in which he served throughout, from Jena to the peace of Tilsit, as a staff officer, and won the rank of major for distinguished service in action. After the peace, and the downfall of Prussia, he was one of the most active of Scharnhorst’s assistants in the work of reorganization (1809), joined the Tugendbund and endeavoured to take part in Schill’s abortive expedition, after which he entered the Austrian service as a major on the general staff. Thereafter he journeyed to Cadiz to assist the Spaniards against Napoleon, and he led a corps of volunteers in the defence of that port against Marshal Victor in 1810. He was present at the battle of Albuera, at Saguntum, and at Valencia, becoming a prisoner of war at the surrender of the last-named place. Soon, however, he escaped to Switzerland, whence early in 1813 he returned to Prussia as a major on the general staff. He served successively under Colonel von Dolffs and General von Kleist, and as commissioner at the headquarters of the Russian general Barclay de Tolly. He took part with Kleist in the victory of Kulm, and recovered from a severe wound received at that action in time to be present at the battle of Leipzig. He played a conspicuous part in the campaign of 1814 in France, after which he was made a major-general. In this rank he was appointed quartermaster-general to Field Marshal Prince Blücher, and, after his chief and Gneisenau, Grolmann had the greatest share in directing the Prussian operations of 1815. In the decision, on the 18th of June 1815, to press forward to Wellington’s assistance (see [Waterloo Campaign]), Grolmann actively concurred, and as the troops approached the battle-field, he is said to have overcome the momentary hesitation of the commander-in-chief and the chief of staff by himself giving the order to advance. After the peace of 1815, Grolmann occupied important positions in the ministry of war and the general staff. His last public services were rendered in Poland as commander-in-chief, and practically as civil administrator of the province of Posen. He was promoted general of infantry in 1837 and died on the 1st of June 1843, at Posen. His two sons became generals in the Prussian army. The Prussian 18th infantry regiment bears his name.
General von Grolmann supervised and provided much of the material for von Damitz’s Gesch. des Feldzugs 1815 (Berlin, 1837-1838), and Gesch. des Feldzugs 1814 in Frankreich (Berlin, 1842-1843).
See v. Conrady, Leben und Wirken des Generals Karl von Grolmann (Berlin, 1894-1896).
GROMATICI (from groma or gruma, a surveyor’s pole), or Agrimensores, the name for land-surveyors amongst the Romans. The art of surveying was probably at first in the hands of the augurs, by whom it was exercised in all cases where the demarcation of a templum (any consecrated space) was necessary. Thus, the boundaries of Rome itself, of colonies and camps, were all marked out in accordance with the rules of augural procedure. The first professional surveyor mentioned is L. Decidius Saxa, who was employed by Antony in the measurement of camps (Cicero, Philippics, xi. 12, xiv. 10). During the empire their number and reputation increased. The distribution of land amongst the veterans, the increase in the number of military colonies, the settlement of Italian peasants in the provinces, the general survey of the empire under Augustus, the separation of private and state domains, led to the establishment of a recognized professional corporation of surveyors. During later times they were in receipt of large salaries, and in some cases were even honoured with the title clarissimus. Their duties were not merely geometrical or mathematical, but required legal knowledge for consultations or the settlement of disputes. This led to the institution of special schools for the training of surveyors and a special literature, which lasted from the 1st to the 6th century A.D. The earliest of the gromatic writers was Frontinus (q.v.), whose De agrorum qualitate, dealing with the legal aspect of the art, was the subject of a commentary by Aggenus Urbicus, a Christian schoolmaster. Under Trajan a certain Balbus, who had accompanied the emperor on his Dacian campaign, wrote a still extant manual of geometry for land surveyors (Expositio et ratio omnium formarum or mensurarum, probably after a Greek original by Hero), dedicated to a certain Celsus who had invented an improvement in a gromatic instrument (perhaps the dioptra, resembling the modern theodolite); for the treatises of Hyginus see that name. Somewhat later than Trajan was Siculus Flaccus (De condicionibus agrorum, extant), while the most curious treatise on the subject, written in barbarous Latin and entitled Casae litterarum (long a school text-book) is the work of a certain Innocentius (4th-5th century). It is doubtful whether Boëtius is the author of the treatises attributed to him. The Gromatici veteres also contains extracts from official registers (probably belonging to the 5th century) of colonial and other land surveys, lists and descriptions of boundary stones, and extracts from the Theodosian Codex. According to Mommsen, the collection had its origin during the 5th century in the office of a vicarius (diocesan governor) of Rome, who had a number of surveyors under him. The surveyors were known by various names: decempedator (with reference to the instrument used); finitor, metator or mensor castrorum in republican times; togati Augustorum as imperial civil officials; professor, auctor as professional instructors.
The best edition of the Gromatici is by C. Lachmann and others (1848) with supplementary volume, Die Schriften der römischen Feldmesser (1852); see also B. G. Niebuhr, Roman History, ii., appendix (Eng. trans.), who first revived interest in the subject; M. Cantor, Die römischen Agrimensoren (Leipzig, 1875); P. de Tissot, La Condition des Agrimensores dans l’ancienne Rome (1879); G. Rossi, Groma e squadro (Turin, 1877); articles by F. Hultsch in Ersch and Gruber’s Allgem. Encyklopädie, and by G. Humbert in Daremberg and Saglio’s Dictionnaire des antiquités; Teuffel-Schwabe, Hist. of Roman Literature, 58.