Page:EB1911 - Volume 13.djvu/910

Rh lengths of the vertical axes are in the ratio 5:7:9, and this is also the ratio of the number of magnesium atoms present in each of the three minerals. These minerals are strikingly similar in appearance, and can only be distinguished by the goniometric measurement of the complex crystals. They are honey-yellow to brown or red in colour, and have a vitreous to resinous lustre; the hardness is 6-6, and the specific gravity 3.1–3.2. Further, they often occur associated together, and it is only comparatively recently that the three species have been properly discriminated. The name humite, after Sir Abraham Hume, Bart. (1749–1839), whose collection of diamond crystals is preserved at Cambridge in the University museum, was given by the comte de Bournon in 1813 to the small and brilliant honey-yellow crystals found in the blocks of crystalline limestone ejected from Monte Somma, Vesuvius; all three species have since been recognized at this locality. Chondrodite (from, “a grain”) was a name early (1817) in use for granular forms of these minerals found embedded in crystalline limestones in Sweden, Finland and at several place in New York and New Jersey. Large hyacinth-red crystals of all three species are associated with magnetite in the Tilly Foster iron-mine at Brewster, New York; and at Kafveltorp in Örebro, Sweden, similar crystals (of chondrodite) occur embedded in galena and chalcopyrite.

The relation mentioned above between the crystallographic constants and the chemical composition is unique amongst minerals, and is known as a morphotropic relation. S. L. Penfield and W. T. H. Howe, who in 1894 noticed this relation, predicted the existence of another member of the series, the crystals of which would have a still shorter vertical axis and contain less magnesium, the formula being Mg[Mg(F, OH)]2SiO4; this has since been discovered and named prolectite (from, “to foretell”).

 HUMMEL, JOHANN NEPOMUK (1778–1837), German composer and pianist, was born on the 14th of November 1778, at Pressburg, in Hungary, and received his first artistic training from his father, himself a musician. In 1785 the latter received an appointment as conductor of the orchestra at the theatre of Schikaneder, the friend of Mozart and the librettist of the Magic Flute. It was in this way that Hummel became acquainted with the composer, who took a great fancy to him, and even invited him to his house for a considerable period. During two years, from the age of seven to nine, Hummel received the invaluable instruction of Mozart, after which he set out with his father on an artistic tour through Germany, England and other countries, his clever playing winning the admiration of amateurs. He began to compose in his eleventh year. After his return to Vienna he completed his studies under Albrechtsberger and Haydn, and for a number of years devoted himself exclusively to composition. At a later period he learned song-writing from Salieri. For some years he held the appointment of orchestral conductor to Prince Eszterhazy, probably entering upon this office in 1807. From 1811 to 1815 he lived in Vienna. On the 18th of May 1813 he married Elisabeth Röckl, a singer, and the sister of one of Beethoven’s friends. It was not till 1816 that he again appeared in public as a pianist, his success being quite extraordinary. His gift of improvisation at the piano was especially admired, but his larger compositions also were highly appreciated, and for a time Hummel was considered one of the leading musicians of an age in which Beethoven was in the zenith of his power. In Prussia, which he visited in 1822, the ovations offered to him were unprecedented, and other countries—France in 1825 and 1829, Belgium in 1826 and England in 1830 and 1833—added further laurels to his crown. He died in 1837 at Weimar, where for a long time he had been the musical conductor of the court theatre. His compositions are very numerous, and comprise almost every branch of music. He wrote, amongst other things, several operas, both tragic and comic, and two grand masses (Op. 80 and 111). Infinitely more important are his compositions for the pianoforte (his two concerti in A minor and B minor, and the sonata in F sharp minor), and his chamber music (the celebrated septet, and several trios, &c.). His experience as a player and teacher of the pianoforte was embodied in his Great Pianoforte School (Vienna), and the excellence of his method is further proved by such pupils as Henselt and Ferdinand Hiller. Both as a composer and as a pianist Hummel continued the traditions of the earlier Viennese school of Mozart and Haydn; his style in both capacities was marked by purity and correctness rather than by passion and imagination.

HUMMING-BIRD, a name in use, possibly ever since English explorers first knew of them, for the beautiful little creatures to which, from the sound occasionally made by the rapid vibrations of their wings, it is applied. Among books that are ordinarily in naturalists’ hands, the name seems to be first found in the Musaeum Tradescantianum, published in 1656, but it therein occurs (p. 3) so as to suggest its having already been accepted and commonly understood; and its earliest use, as yet traced, is by Thomas Morton (d. 1646), a disreputable lawyer who had a curiously adventurous career in New England, in the New English Canaan, printed in 1637—a rare work giving an interesting description of the natural scenery and social life in New England in the 17th century, and reproduced by Peter Force in his Historical Tracts (vol. ii., Washington, 1838). André Thevet, in his Singularitez de la France antarctique (Antwerp, 1558, fol. 92), has been more than once cited as the earliest author to mention humming-birds, which he did under the name of Gouambuch; but it is quite certain that Oviedo, whose Hystoria general de las Indias was published at Toledo in 1525, preceded him by more than thirty years, with an account of the “paxaro mosquito” of Hispaniola, of which island “the first chronicler of the Indies” was governor. This name, though now apparently disused in Spanish, must have been current about that time, for we find Gesner in 1555 (De avium natura, iii. 629) translating it literally into Latin as Passer muscatus, owing, as he says, his knowledge of the bird to Cardan, the celebrated mathematician, astrologer and physician, from whom we learn (Comment. in Ptolem. de astr. judiciis, Basel, 1554, p. 472) that, on his return to Milan from professionally attending Archbishop Hamilton at Edinburgh, he visited Gesner at Zürich, about the end of the year 1552. The name still survives in the French oiseau-mouche; but the ordinary Spanish appellation is, and long has been, Tominejo, from tomin, signifying a weight equal to the third part of an adarme or drachm, and used metaphorically for anything very small. Humming-birds, however, are called by a variety of other names, many of them derived from American languages, such as Guainumbi, Ourissia and Colibri, to say nothing of others bestowed upon them (chiefly from some peculiarity of habit) by Europeans, like Picaflores, Chuparosa and Froufrou. Barrère, in 1745, conceiving that humming-birds were allied to the wren, the Trochilus, in part, of