Page:EB1911 - Volume 21.djvu/493

Rh left-hand side of each drawings, by Boeke's method, of two periods of the marks of the vowel. The marks are shown for the Dutch, German, English and French languages. The sounds of the vowels “ go “, oe, like oo in “ too ”; u, l1ke the German u a, like a in “ hard "; e, like a in “ take ”; fzj, not in are 0, like o in

in H Fuhrer ”;

English words, but somewhat like é in “bell ”; and z, like ee in “ beer." The

either sung or

second section

first section contains only Dutch vowel sounds, spoken by Boeke or members of his family. The contains curves from the voice of Professor Hermann, the third from the voice of the author from a cylinder sent by him to Dr Boeke, and the fourth from the voice of Mons H. Marichelle, professeur de llnstitut des Sourds-Muets, also forwarded by him to Dr Boeke Thus curves and marks of the same vowel are shown from the o1ces of men of four nationalities. On the construction of the gramophone, see L. N. Reddie, Journ. ''Soc. Arts'' (1908).

PHONOLITE (Gr. φωνή, sound, λίθος, stone), in petrology, a group of volcanic lavas containing much nepheline and sanidine felspar. The term “ clinkstone " was formerly given by geologists to many fine grained compact lavas, which split into thin tough plates, and gave out a ringing sound when struck with the hammer. Some of these clinkstones were phonolites in the modern sense, but as the name clinkstone was used for a large variety of rocks, many of which have no close affinities with one another, it has been discarded and “ phonolite ” is substituted for it. The group includes rocks which are rich in alkalis with only a moderate percentage of silica; hence they contain no free quartz but much alkali felspar (sanidine and anorthoclase) and nepheline. Large plates of sanidine are often visible in the rocks; the nepheline is usually not obvious to the unaided eye. Most phonolites show fluxion structure, both in the orientation of their phenocrysts and in the smaller crystals which make up the ground mass, and this determines to a large extent the platy jointing. Although vitreous and pumiceous forms are known they are rare, and in the great majority of cases these rocks are finely crystalline with a dull or shimmering lustre in the ground-mass. Marked characteristics are the readiness with which they decompose, and the frequency of veins and cavities occupied by natrolite, analcite, scolecite and other zeolites. Small black grains of augite or hornblende and sometimes blue specks of hauyne may be seen in the rocks when they are fresh.

The dominant minerals are sanidine, nepheline, pyroxene, amphibole, various felspathoids and iron oxides. The sanidine is usually in two generations, the first consisting of large crystals of flattened and tabular shape, while the second generation is represented by small rectangular prisms arranged in parallel streams in the ground-mass; these felspars are nearly always simply twinned on the Carlsbad plan. They contain often as much soda as potash. The nepheline takes the form of hexagonal prisms with flat ends, and may be completely replaced by fibrous zeolites, so that it can only be recognized by the outlines of its pseudomorphs. In some phonolites it is exceedingly abundant in the ground-mass, and these rocks form transitions to the nephelinites (nephelinitoid phonolites) (see, Plate III. fig. 1), in others it is scarce and the rocks resemble trachytes containing a little nepheline (trachytoid phonolites). The felspathoid minerals, sodalite, hauyne and nosean, which crystallize in isometric dodecahedra, are very frequent components of the phonolites; their crystals are often corroded or partly dissolved and their outlines may then be very irregular. Small rounded enclosures of glass are often numerous in them. The pyroxenes may be pale green diopside, dark green aegirine-augite, or blackish green aegirine (soda iron pyroxene), and in many cases are complex, the outer portions being aegirine while the centre is diopside. Fine needles of aegirine are often found in the ground-mass. The commonest hornblende is dark brown barkevicite. Biotite and olivine are not really frequent in these rocks, and usually have been affected by resorption. The ordinary accessory minerals of igneous rocks, apatite, magnetite and zircon occur in the phonolites, and sphene is often rather common. Another mineral which is more frequent in phonolites than in many other rocks is brown melanite garnet.

The majority of the rocks of this group are of Tertiary or Recent age, but in Scotland Carboniferous phonolites occur in several localities, e.g. Traprain in Haddingtonshire, also in the Eildon Hills and in Renfrewshire. In Brazil phonolites belonging to the same epoch are also known. There are several districts in Europe where Tertiary or Recent phonolites occur in considerable numbers, as in Auvergne (Mont Dore), the Eifel, and Bohemia. The Wolf Rock which lies off the south coast of Cornwall, and is the site of a well-known lighthouse, is the only mass of phonolite in England; it is supposed to be the remains of a Tertiary lava or intrusion. The Canary Islands, Cape Verde Islands, Sardinia, Aden, British East Africa and New Zealand contain many types of phonolites; they are known also in New South Wales, while in the United States phonolites occur in Colorado (at Cripple Creek) and in the Black Hills of South Dakota.

Leucite occurs in place of nepheline in a small group of phonolites (the leucite-phonolites), known principally from Rocca Monfina and other places near Naples. Blue hauyne is rather a conspicuous mineral in some of these rocks, and they also contain a good deal of sphene. When sanidine, nepheline and leucite all occur together in a volcanic rock it is classed among the leucitophyres (see, Plate III. fig. 2). The chemical analyses of phonolites given below show that these rocks are very rich in alkalis and alumina with only a moderate amount of silica, while lime, magnesia and iron oxides are present only in small quantity. They have a close resemblance in these rcspects to the nepheline-syenites of which they provide the effusive types.

 PHORCYS, in Greek mythology, son of Pontus (Sea) and Gaea (Earth), father of the Graeae, the Gorgons, Scylla, and Ladon (the dragon that guarded the golden apples of the Hesperides). In Homer (Odyssey, xiii. 96) he is an aged sea-deity, after whom a harbour in Ithaca was named. According to Varro (quoted by Servius in Aeneid, v. 824) Phorcys was a king of Corsica and Sardinia, who, having been defeated by King Atlas in a naval engagement in the course of which he was drowned, was subsequently worshipped as a marine divinity.

PHORMIUM, or (also called “ New Zealand hemp ”), a fibre obtained from the leaves of Phormium tenax (nat. ord. Liliaceae), a native of New Zealand, the Chatham Islands and Norfolk Island. This useful plant is one of the many which were discovered by Sir Joseph Banks and Dr Solander who accompanied Captain Cook on his first voyage of discovery. The seeds brought home by Banks in 1771 did not succeed, but the plant was introduced by him to the Royal Gardens at Kew in 1789, and was thence liberally distributed in Great Britain and the continent of Europe. It grows luxuriantly in the south of Ireland, where it was introduced in 1798, and also flourishes on the west coast of Scotland, and is generally cultivated as an ornamental garden plant in Europe. It has been introduced for economic purposes into the Azores and California. The name Phormium is from Gr. φορμός, a basket, in allusion to one of the uses made of its leaves by the New Zealanders.

In its native country the plant is generally found near the coast. It has a fleshy rootstock, creeping beneath the surface of the soil and sending up luxuriant tufts of narrow, sword-shaped leaves, from 4 to 8 ft. long and from 2 to 4 in. in diameter. The leaves are vertical, and arranged in two rows as in the garden flag; they are very thick, stiff and leathery, dark green above, paler below, with the margin and nerve reddish orange. From the centre of the tuft ultimately arises a tall flower-bearing stem, 5 to 15 ft. high, bearing on its numerous