PLAIN-SONGPLANETS. 



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one third spirit, I gave one-half, every eight hours 

 no intoxication came on, but a lethargic drowsiness 

 was common enough, continuing till the perspira- 

 tion broke out, or carbuncles appeared externally. 

 If, on the third day, the patient was decidedly better 

 I kept up the excitement with strong Cyprus wine, 

 in frequent but small doses of two table-spoonsful 

 every two hours ; but, if the bad symptoms were 

 unabated, I continued to give the hot brandy and 

 water in increased quantities, till some decided 

 change took place. This active treatment it was 

 seldom necessary to pursue beyond the sixth day; 

 indeed, in plague, if the patient live to the sixth 

 day, he is very likely to recover ; but the third day 

 is that which is most to be feared. The only other 

 treatment was once or twice opening the bowels 

 with enemas, for purgatives by the mouth do no 

 service, and sponging the body frequently with 

 vinegar and water ; the head was constantly kept 

 soaked with towels dipped in vinegar, and the bu- 

 boes were poulticed with very hot cataplasms, suffi- 

 ciently hot to give pain, and they were allowed to 

 burst spontaneously. With this treatment, at the 

 rate of seventy-five per cent, recovered. In Candia, 

 of nine patients, five recovered ; and some of these 

 were almost hopeless cases when I began to treat 

 them. Every thing in plague of course depends on 

 early treatment ; for, in a disease which commonly 

 runs its course in three days, there is no time to be 

 lost." 



PLAIN-SONG; the name given to the old eccle- 

 siastical cliant, when in its most simple state, and 

 without those harmonic appendages with which it 

 has long since been enriched by cultivated science. 

 PLANE, INCLINED. See Mechanics. 

 PLANETARIUM. See Orrery. 

 PLANE TREE. The Occidental plane, or but- 

 tonwood (plutanus Occidentalis), is, among deciduous 

 trees, the largest production of the American forest. 

 It abounds most and attains the largest size along 

 the interior waters of Pennsylvania and Virginia, 

 and especially along the banks of the Ohio. Here 

 stocks are sometimes found from ten to fourteen feet 

 in diameter, often beginning only to give out their 

 vast branches at the height of sixty or seventy feet, 

 and near the summits of the surrounding trees. At 

 other times, this tree divides at the base into several 

 huge trunks, equally surpassing its neighbours in 

 bulk. A moist and cool soil seems indispensable, 

 for it is never found on dry grounds. In the West- 

 ern States, this tree is usually known by the name 

 of sycamore, and in some districts is called cotton- 

 tree. The trunk and branches are covered with a 

 smooth, pale-green bark, the epidermis of which 

 detaches itself in portions ; the roots, when first 

 taken from the earth, are of a beautiful red colour, 

 which disappears on exposure to light in a dry place ; 

 the leaves are alternate, palmated, or lobed; and the 

 flowers are united in little globular, pendent balls. 

 The wood, in seasoning, takes a dull red colour, is 

 fine-grained, and susceptible of a good polish, but 

 speedily decays on exposure to the weather. When 

 thoroughly seasoned, it may be used in the interior 

 of houses, but the defect of warping is attributed to 

 it, and cabinet-makers rarely employ it except for 

 bedsteads, which, when coated with varnish, retain 

 their colour. 



The oriental plane, so celebrated by the ancients 

 for the majesty of its appearance, resembles the pre- 

 ceding in every respect, and bears the same relation 

 to the forests of Western Asia. The wood, in those 

 regions where it abounds, is frequently employed in 

 the arts, and is said to acquire great hardness by 

 being kept under water for some years. 



PLANETS (from v*.tt,vaa, to wander); moving 

 v. 



stars, which shine by reflecting the light of the sun, 

 around which they revolve. Homer and Hesiod 

 were already acquainted with Venus, but considered 

 the morning and evening stars as two different bo- 

 dies. Democritus supposed that there were several 

 planets. Pythagoras discovered the identity of the 

 morning and evening stars; and, in the fourth year 

 before Christ, Eudoxus brought the knowledge of 

 the motions of the five planets then known, from the 

 Egyptians to the Greeks. In addition to these five 

 planets, Mercury, Venus, Mars, Jupiter, and Saturn, 

 five others have been discovered in modern times : 

 Herschel (Georgium Sidus, or Uranus), Ceres, Pal- 

 las, Juno, and Vesta ; so that, including the earth 

 and moon, there are now known eleven primary and 

 eighteen secondary planets (satellites, or moons). 

 Like the earth, many of them, if not all, have the 

 motion of rotation on their axis, whence arise day 

 and night, and a common motion around the sun, 

 around which they revolve from west to east, through 

 south, in elliptical orbits, generally making a small 

 angle with the ecliptic in different times, depending 

 on their distances from the sun. 



The planet nearest the sun is Mercury, though 

 thirty-seven millions of miles distant from it. It 

 completes its revolution around the sun in eighty- 

 eight days, moving with a velocity of 315 miles a 

 second. It is the smallest of the six old planets, its 

 bulk being only one-eighteenth of that of the earth. 

 Its time of rotation on its axis is twenty-four hours, 

 five and a half minutes, and its eccentricity is much 

 greater than that of either of the other five old pla- 

 nets, or of Uranus. 



Next to Mercury is placed Venus, at a distance of 

 sixty-eight millions of miles from the sun, around 

 which it revolves in 225 days, having a mean velo- 

 city of twenty-one miles a second. It turns on its 

 axis in twenty-three hours twenty-one minutes, as is 

 known from observation of the spots on its surface. 

 Mountains have also been observed in it, the height 

 of some of which is computed to exceed eighteen 

 miles. Seen from the earth, Venus and Mercury 

 exhibit phases similar to those of the moon, some- 

 times appearing nearly full, sometimes half illumi- 

 nated, or in the form of a crescent, and sometimes 

 becoming invisible by turning to us the dark side. 

 In size, Venus is nearly equal to the earth, and in her 

 perigee approaches it within 27,600,000 miles, 

 though in her apogee, she may recede 165,600,000 

 miles from it. We have no certain knowledge of a 

 moon belonging to Venus; the supposed discovery 

 of one seems to have been founded on a mistake. 

 Mercury and Venus appear,, at times, like black 

 spots passing across the face of the sun, whenever, 

 in their motion in their orbits, like the moon in solar 

 eclipses, they enter the plane of the ecliptic within 

 a few hours of their inferior conjunction. This phe- 

 nomenon is called a transit of Mercury or Venus. 

 A transit of the latter planet is of rare occurrence, 

 two only taking place in about 120 years. Those 

 of Mercury are much more frequent. The next 

 transit of Venus will take place in 1874. These 

 two planets, which are nearer to the sun than the 

 earth, are called the inferior planets, and those more 

 distant are called the superior. 



Next in order to the earth (q. v.) and its moon 

 (q. v.) is Mars, 143 million miles distant from the 

 sun. In its orbit, which it accomplishes in one 

 year and 322 days, it moves with a velocity of 

 Sfteen miles a second. It is flattened at the poles 

 about one-sixteenth of its diameter, and turns once 

 in twenty-four hours thirty-nine minutes on its axis, 

 which is inclined to the plane of its orbit at an 

 angle of sixty-one degrees. The surface of Mars 

 "s about one-fourth that of the earth, and, his den- 

 2o 



