Page:Encyclopædia Britannica, Ninth Edition, v. 18.djvu/232

P A N P A N landscape from this position on the cylinder. In a : panorama such a cylinder, originally of about 60 feet, j but now extending to upwards of 130 feet diameter, is ; covered with an accurate representation in colours of a landscape, so that an observer standing in the centre of the cylinder sees the picture like an actual landscape in nature completely surround him in all directions. This gives an effect of great reality to the picture, which is skilfully aided in various ways. The observer stands on a platform representing, say, the flat roof of a house, and the space between this platform and the picture is covered with real objects which gradually blend into the picture itself. The picture is lighted from above, but a roof is spread over the central platform so that no light but that reflected from the picture reaches the eye. In order to make this light appear the more brilliant, the passages and staircase which lead the spectator to the platform are kept nearly dark. These panoramas were invented by Robert Barker, an Edinburgh artist, who exhibited the first in Edinburgh in 1788, representing a view of that city. A view of London and views of sea fights and battles of the Napoleonic wars followed. Panoramas gained less favour on the Continent, until after the Franco-German war a panorama of the siege of Paris was exhibited in Paris. The name panorama, or panoramic view, is also given to drawings of views from mountain peaks or other points of view, such as are found in many hotels in the Alps, or, on a smaller scale, in guide-books to Switzerland and other mountainous districts. These too are drawn as if projected on a cylinder afterwards cut open and unrolled, The geometrical laws which guide the drawing of panoramas follow easily from the general rules for PROJECTION (q.v.). PANSY (Viola sp.). This flower has been so long cultivated that its source is a matter of uncertainty. As we now see it, it is a purely artificial production, differing considerably from any wild plant known. By some it is supposed to be merely a cultivated form of Viola tricolor, a corn-field weed, while others assert it to be the result of hybridization between V. tricolor and other species such as V. altaica, V. grandiflora, &c. As florists and gardeners conducted, and still too often conduct, their operations without scientific method, it is unfortunately not possible to arrive at any definite conclusion on this point. Some experiments of M. Carriere, however, go to show that seeds of the wild V. tricolor will produce forms so like those of the cultivated pansy that it is reasonable to assume that that flower has originated from the wild plant by con tinuous selection. Mr Darwin confesses himself to have been foiled in the attempt to unravel the parentage of the pansy, " and gave up the attempt as too difficult for any one except a professed botanist." The changes that have . been effected from the wild type are, however, more strik ing to the eye than really fundamental. Increase in size, an alteration in form by virtue of which the narrow oblong petals are converted into circular ones, and variations in the intensity and distribution of the colour these are the changes that have been wrought by continued selection, while the more essential parts of the flower have been j relatively unaffected. The stamens and pistil, in fact, present the characteristics of the genus Viola. In that ; genus the construction of the stamens and pistil is such as ; to favour cross-fertilization, and that circumstance alone would account for much of the variation that is observed. : In practice it is customary to propagate by means of j cuttings the varieties it is desired to perpetuate, while, if : additional varieties are desired, reproduction by seed, and careful selection of seedlings, according to the desire or , fancy of the cultivator, are had recourse to. Self-fertilizing , (cleistogamic) flowers, such as occur in various species of violet, and in which the petals are absent or inconspicuous, not being required for the purpose of attracting insects, have not as yet been observed in pansies. PANT/ENUS, head of the catechetical school at Alexandria at the close of the 2d Christian century, is known chiefly as having been the master of Clement, who succeeded him. Eusebius and Jerome speak of him as having been, originally at least, a Stoic, and as having been sent, on account of his zeal and learning, as a missionary to "India"- Yemen perhaps being meant. He was the author of commentaries on various books of Scripture, all of which have been lost with the exception of a few insignificant fragments. His teaching work in Alexandria seems to have begun before 180 A.D., and it was brought to an end by the persecution of Septimius Severus in 202. PANTELLARIA, PANTALARIA, or officially PASTEL- LERIA (the ancient Cossyra or Cosyra), an island in the Mediterranean, which, though only 45 miles from the African coast to the south of Cape Bon, and 75 miles from the coast of Sicily, is included in the Italian province and circondario of Trapani. It is of volcanic origin, and its area is estimated at 58 square miles. Its principal sum mit reaches a height of 2-140 feet. Hot sulphur springs occur in various places, and there is a small salt-lake of somewhat high temperature ; but there is a lack of fresh water. The principal town, Oppidolo or Pantellaria, on the north-west, lies round a port protected by two redoubts and a citadel now used as a prison. Trade is carried on with Algeria, Tunis, and Malta, From 131 vessels (12,917 tons) in 1863 the movement of the port had by 1880 in creased to 923 vessels (83,524 tons). In 1881 the popula tion of the town was 3167, that of the island 7315. The Phoenician name D3~1K, Iranim, on coins has led Rcnan to identify the island with the Inarime of the Latin poets. The cap ture of Cosyra by M. jEmilius and Servius Fulvius in the First Punic War was thought worth mentioning in the triumphal fasti, though the Carthaginians recovered possession in the fol lowing year. In modern times the island has formed a princi pality in the hands of the Requesens family. The bastard Italian spoken by the inhabitants shows Arabic influence. PANTHEISM. See THEISM. PANTHER. See LEOPARD. PANTOGRAPH is an instrument for making a reduced, an enlarged, or an exact copy of a plane figure. One of the simplest forms is represented in fig. 1. Four links of wood or metal are jointed together so as to form a parallelogram ABCS. On two sides BA and BC produced points P and P are taken in a line with S, so that the triangles PSA and SP C are similar, as the sides of the T ~ B O Fig. 1. Fig- 2. one are parallel to those of the other. Hence SA AP = P C/CS. Now the parallelogram ABCS is movable, its angles changing Avhilst its sides remain unaltered. The above ratio will therefore remain constant, and therefore again the points PSP will always remain in a line. At the same time the ratio PS/SP does not change, as it equals the ratio PA/AB. If then the point S be kept