712 P E T P E T and thought to be either very nearly allied to the Gulls, Laridx, or intermediate between that Family and the Steganopodes ; but this opinion has gradually given way, and it is now hard to resist the conclusion that they have to be regarded as an "Order," to which the name Tubinares has been applied from the tubular form of their nostrils, a feature possessed in greater or less degree by all of them, and by which each may at a glance be recognized. They have usually been subdivided into three groups or Sub families, (1) Pelecanoidinx (or Halodrominse), containing some three or four species known as Diving-Petrels, with habits very different from others of the Family, and almost peculiar to high southern latitudes from Cape Horn to New Zealand; (2) Procellariinse, or Petrels proper; and (3) Diomedeinx, or Albatrosses (cf. MALLEMUCK, vol. xv. p. 334). Recently, however, the anatomy of the group has been subjected to very close examination by Garrod and W. A. Forbes, the latter of whom has summed up the results obtained by himself and his predecessor in an ela borate essay, forming part ix. of the Zoology of the voyage of the " Challenger," which shew determinations that differ greatly from any that had been reached by prior system- atists. According to these investigators, the Tubinares are composed of two Families, Procellariidse, and Oceanitidx, whose distinctness had never before been suspected 2 the latter consisting of four genera not very much differing in appearance from many others, while the former includes as Subfamilies the Albatrosses, Diomedeinse, with three genera, Diomedea, Thalassiarche, and Phcebetria, and the true Petrels, Procellariinse, in which last are combined forms so different externally and in habit as the Diving-Petrels, above noticed, the Storm-Petrels, Procellaria, the Flat-billed Petrels, Prion, the FULMAE (vol. ix. p. 817), the SHEAR WATERS (q.v. and others. Want of space forbids us here dwelling on the characters assigned to these different groups, or the means which have led to this classification of it, set forth at great length in the essay cited, where also will be found copious references to previous studies of the Petrels, among which may here be especially men tioned those of MM. Hombron and Jacquinot (Comptes Rendus, 1844, pp. 353-358, and Zool. Voy. au Pol Sud, vol. iii.), Prof. Coues (Proc. Acad. Philadelphia, 1864, pp. 72-91, 116-144, and 1866, pp. 25-33, 134-197), and Mr Salvin (Orn. Miscellany, ii. pp. 223-238, 249-257; and Zoology, Voy. "Challenger" pt. viii. pp. 140-149). Petrels are dispersed throughout all the seas and oceans of the world, and some species apparently never resort to land except for the purpose of nidification, though nearly all are liable at times to be driven ashore, and often very far inland, by gales of wind. 3 It would also seem that during the breeding-season many of them are wholly noc turnal in their habits, passing the day in holes of the ground, or in clefts of the rocks, in which they generally nestle, the hen of each pair laying a single white egg, sparsely speckled in a few species with fine reddish dots. Of those species that frequent the North Atlantic, the common Storm-Petrel, Procellaria pelagica, a little bird which has to the ordinary eye rather the look of a Swift or Swallow, is- the " Mother Carey s chicken " of sailors, and is widely believed to be the harbinger of bad weather ; but seamen hardly discriminate between this and others nearly resembling it in appearance, such as Leach s or the 1 Most commonly but erroneously spelt Procdlaridas. - It is due to Prof. Coues to state that in 1864 he had declared the genus Oceanites, of which he only knew the external characters, to be " the most distinct and remarkable " of the " Procellariese, " though he never thought of making it the type of a separate Family. 3 Thus (Estrelata hassitata, the Capped Petrel, a species whose proper home seems to be Guadeloupe and some of the neighbouring West-Indian Islands, has occurred in the State of New York, near Boulogne, in Norfolk, and in Hungary (Ibis, 1884, p. 202) ! Fork-tailed Petrel, Cymochorea leucorrhoa, a rather larger but less common bird, and Wilson s Petrel, Oceanites oceanicus, the type of the Family Oceanitidx mentioned above, which is more common on the American side. But it is in the Southern Ocean that Petrels most abound, both as species and as individuals. The Cape-Pigeon or Pintado Petrel, Daption capensis, is one that has long been well known to mariners and other wayfarers on the great waters, while those who voyage to or from Australia, whatever be the route they take, are certain to meet with many more species, some, as Ossifraga gigantea, as large as Alba trosses, and several of them called by sailors by a variety of choice names, generally having reference to the strong smell of musk emitted by the birds, among which that of " Stink-pot " is not the most opprobrious. None of the Petrels are endowed with any brilliant colouring sooty- black, grey of various tints (one of which is often called " blue " ), and white being the only hues their plumage exhibits ; but their graceful flight, and their companion ship when no other life is visible around a lonely vessel on the widest of oceans, give them an interest to beholders, though this is too often marred by the wanton destruction dealt out by brutal or thoughtless persons who thus seek to break the tediousness of a long voyage. The distri bution of the several species of Petrels in the Southern Ocean has been ably treated by Prof. A. Milne-Edwards in the Annales des Sciences Naturelles for 1882 (ser. 6, Zoo- logie, vol. xiii. art. 4, pp. 1-22), of which essay a transla tion will be found in the Mittheilungen des Ornithologischen Vereins in Wien for 1884. (A. N.) PETRIE, GEORGE (1790-1866), Irish antiquary, was the son of James Petrie, a native of Aberdeen, who had settled in Dublin as a portrait and miniature painter. He was born in Dublin in January 1790, and was educated to become a painter. Besides attaining considerable reputa tion as a landscape painter of Irish scenes, he devoted much of his artistic skill to the illustration of the anti quities of the country. Even in boyhood his love of archaeology vied with his love of art and of nature. In 1828 he was appointed to conduct the antiquarian and historical section of the Ordnance Survey of Ireland, but this department of the work was not persevered in by the Government. In 1832 he became editor of the Dublin Penny Journal, a periodical designed to disseminate in formation among the masses, to which he contributed numerous articles on the history of the fine arts in Ireland. Petrie may be regarded as the first scientific investigator of Irish archaeology, his contributions to which are also in themselves of prime importance. His Essay on Round Towers, for which in 1830 he received the prize of the Irish Academy, must still rank, whether or not his opinion be accepted that the round towers served the joint purpose of belfries and fortalices, as the standard work on the subject. A second edition was published in 1845. Among his other more important contributions to Irish archaeology are his Essay on the Military Architecture of Ireland and his History and Antiquities of Tar a Hill. In 1847 he received the degree of LL.D. from the university of Dublin, and in 1849 he was placed on the civil list for an annual pension of 300. He died 17th January 1866. See the Life aiid Labours in Art and Archaeology of George Petrie, by William Stokes, 1868. PETROLEUM. The word "petroleum" (rock-oil; Germ., erdol, steinoT) is used to designate the forms of bitumen that are of an oily consistence. It passes by insensible gradations into the volatile and ethereal naph thas on the one hand and the semi-fluid malthas or mineral- tars on the other. History. Petroleum has been known by civilized man
