MacGREGOR, JOHN [”Rob Roy”] (1825-1892), Scottish canoeist, traveller and philanthropist, son of General Sir Duncan MacGregor, K.C.B., was born at Gravesend on the 24th of January 1825. He combined a roving disposition with a natural taste for mechanics and for literature. In 1839 he went to Trinity College, Dublin, and in 1844 to Trinity, Cambridge, where he was a wrangler. He was called to the bar in 1851, but did not pursue his profession. He travelled a great deal in Europe, Egypt, Palestine, Russia, Algeria and America, and between 1853 and 1863 was largely occupied with researches into the history and methods of marine propulsion. He was the pioneer of British canoeing. In 1865 he started on a long canoeing cruise in his “Rob Roy” canoe, and in this way made a prolonged water tour through Europe, a record of which he published in 1866 as A Thousand Miles in the Rob Roy Canoe. This book made MacGregor and his canoe famous. He made similar voyages in later years in Norway, Sweden and Denmark, the North Sea and Palestine. Another voyage, in the English Channel and on French waters, was made in a yawl. He published accounts of all these journeys. He did not, however, confine his energies to travelling. He was active in charity and philanthropic work, being one of the founders of the Shoe-black Brigade. In 1870 and again in 1873 he was elected on the London school board. He died at Boscombe on the 16th of July 1892.
MACH, ERNST (1838- ), Austrian physicist and psychologist, was born on the 18th of February 1838 at Turas in Moravia, and studied at Vienna. He was professor of mathematics at Gratz (1864-1867), of physics at Prague (1867-1895), and of physics at Vienna (1895-1901). In 1879 and 1880 as Rector Magnificus he fought against the introduction of Czech instead of German in the Prague University. In 1901 he was made a member of the Austrian house of peers. In philosophy he began with a strong predilection for the physical side of psychology, and at an early age he came to the conclusion that all existence is sensation, and, after a lapse into noümenalism under the influence of Fechner’s Psychophysics, finally adopted a universal physical phenomenalism. The Ego he considers not an entity sharply distinguished from the Non-ego, but merely, as it were, a medium of continuity of sensory impressions. His whole theory appears to be vitiated by the confusion of physics and psychology.
Works.—Kompendium der Physik für Mediziner (Vienna, 1863); Einleitung in die Heimholtz’sehe Musiktheorie (Gratz, 1866); Die Gesch. u. d. Wurzel d. Satzes von d. Erhaltung d. Arbeit (Prague, 1872); Grundlinien d. Lehre v. d. Bewegungsempfindungen (Leipzig, 1875); Die Mechanik in ihrer Entwickelung (Leipzig, 1883; rev. ed., 1908; Eng. trans., T. J. McCormack, 1902); Beiträge zur Analyse d. Empfindungen (Jena, 1886), 5th ed., 1906, entitled Die Analyse d. Empfindungen; Leitfaden d. Physik für Studierende (Prague, 1881, in collaboration); Populärwissenschaftliche Vorlesungen (3rd ed., Leipzig, 1903); Die Prinzipien d. Wärmelehre (2nd ed., 1900); Erkenntnis und Irrtum (Leipzig, 1905).
MACHAERODUS, or Machairodus, the typical genus of a group of long-tusked extinct cats, commonly known as sabre-tooths. Although best regarded as a sub-family (Machaerodontinae) of the Felidae, they are sometimes referred to a separate family under the name Nimravidae (see [Carnivora]). The later forms, as well as some of the earlier ones, are more specialized as regards dentition than the modern Felidae, although in several other respects they exhibit more primitive features. The general type of dentition is feline, but in some instances more premolars are retained, as well as a small tubercular molar behind the lower carnassial. The characteristic feature is, however, the great development of the upper canines, which in the more specialized types reach far below the margin of the lower jaw, despite the development of a flange-like expansion of the extremity of the latter for their protection. In these extreme forms it is quite evident that the jaws could not be used in the ordinary manner; and it seems probable that in attacking prey the lower jaw was dropped to a vertical position, and the huge upper tusks used as stabbing instruments. The group is believed to be derived from a creodont allied to the Eocene Palaeonictis (see [Creodonta]).
Nimravus, of the American Oligocene, with two premolars and two molars in the lower jaw, and comparatively short upper canines, seems to be the least specialized type; next to which comes Hoplophoneus, another North American Oligocene genus, in which the tubercular lower molar is lost, and the upper canine is longer. It is noteworthy, however, that this genus retains the third trochanter to the femur, which is lost in Nimravus. Machaerodus, in the wider sense, includes the larger and more typical forms. In the Pliocene of France and Italy it is represented by M. megantereon, a species not larger than a leopard, and allied forms occur in the Pliocene of Greece, Hungary, Samos, Persia, India and China, as well as in the Middle Miocene of France and Germany. Far larger is the Pleistocene M. cultridens of the caverns of Europe, with serrated upper tusks several inches in length. From Europe and Asia the sabre-toothed tigers may be traced into North and thence into South America, the home of M. (Smilodon) neogaeus, the largest of the whole tribe, whose remains occur in the Brazilian caves and the silt of the Argentine pampas. This animal was as large as a tiger, with tusks projecting seven inches from the jaw and very complex carnassials; the feet were very short, with only four toes to the hind-pair, and the humerus has lost the foramen at the lower end. Very noteworthy is the occurrence of an imperfectly known specialized type—Eusmilus—in the Lower Oligocene of Europe and perhaps also North America. Unlike all other cats, it had only two pairs of lower incisors, and the large cheek-teeth were reduced to the carnassial and one premolar in advance of the same.
(R. L.*)