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Show [ 12 J With airy lens the fcatter' d rays afrault, And bend the twilight round the dufky vault; Ride, with broad eye and fcintillating hair, The rapid Fire-baH through the midnight air ~ Dart from the North· on pale elearic flreams, Fringing Night's fable robe with tranfient beams. 130 -OR rein the Planets in their f wift careers, Gilding with borrow' d light their twinkling fpheres ; Alarm with comet-blaze the fapphire plain, The wan fl:ars glimmering through its filver train ; meteorology. And Mr. Lavoi!ier has announced' his delign to write on this fi 0· a Traiti! de Chimie, Tom. I. I am happy to find thefe opinions fupported ~y ~~ch refpectable authority. . And bend the twilight. 1. I 26. The crepufcular atmofphere, or the region where the· hght of the fun ceafes to be refraaed to us, is e!l:imated by philofophers to b b t . 4 d ·1 h' h . e e ween o an so mi h · f he s ·I g . , at which time the fun is about 18 degrees below the h on· zon,. and · t e ranty 0 t e a1r IS fuppofed to be from 4,ooo to Io,ooo times greater than at the fur-face of the e~rth: Cotes's ~ ydro!l:. p. 123._ The duration of twilight differs in different fefa f0o ns and m d1fferent latitudes·' in England the ih or t e1n1 t WI· 1·1 g· h t 1· s a b out the beg·m m· ng· 0:h 8: 8 ober and of March ; in more northern latitudes, where the fun never finks more t . an I .d egrees '. below the h on·z on, t h e twi·l i· ght contm· ues the whole ni ht. The tf.i mhe of IAts duration may alfo be .o ccafionally affeaed by th e vary.m g 11 e1. g h tog f t h eatmo-p ere. number ~f obferv~tions; on the duration of twilight in different latitudes mi ht affordf i cho nfiderable m. formatw.n concerning th e a·e· n·a 1 1n1r ata m• the hi• gher regi• ons of gth e :~~ P ere, anhd dmight affi!l: ~n determining whether an exterior atmofphere of inflama e gas, or y rogene, exJ!l:s over the aerial one. , Alarm with Comet-h/au. 1. 133· See additional notes, No. IV. [ J 3 ] Gem the bright Zodiac, fl:ud the glowing pole, Or give the Sun's phlogiftic orb to roll. 135 III. "NYMPHS t· YOUR fine forms with fieps impaffive mock Earth's vaulted roofs of adamantine rock ; Round her £till centre tread the burning foil, And watch the billowy Lavas, as they boil ; Where, in bafaltic caves imprifon' d deep, ReluCtant fires in dread fufpenfion :lleep;. Or fphere on fphere in widening waves expand, And glad with genial warmth the incumbent land. So when the Mother-bird feleas their food With curious bill, and feeds her callow brood ;_ The Sun's phlogiflic orb. I. 136. See additional notes, No. V. 145 Round her flill centre, 1. 139· Many philofophers have believed that the central parts of the earth confi!l: of a fiuid mafs of burning lava, which they have called a fubterraneous fun ; and have fuppofed, that it contributes to the production of metals, and to the growth of vegetables. See additional notes, No. VI. Or JPht.re onJPhere.. 1. 143· See additional notes, No. VII •. |
