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Show [ 174 ] Higher and yet higher the expanding bubble flies, Lights with quick flafh, and burfis amid the tkies.Headlong l-Ie rufhes through the affrighted Air With lirnbs ·diftorted, and difhevel' d hair, 'Vhirls round and round, the flying croud alarn1s, 155 And DEATH receives hitn in his fable arms !- So erft with tnelting wax and loofen' d flringi Sunk haplefs IcARUS on unfaithful wings ; His fcatter'd plun1age danced upon the wave, And forrowing Mermaids deck' d his watery grave 160 0' er his pale corfe their pearly fea-flowers fhed, And {hew' d with crimfon mofs his marble bed ; Struck in their coral towers the paufing bell, And wide in ocean toll' d his echoing knell. .And wide in ocean. 1. 164. Denfer bodies propagate vibration or found better than rarer ones; if two fl:ones be Uruck together under the water, they may be heard a mile -or two by auy one whofe head is i mmerfed at that difl:ance, according to an experiment of Dr. Franklin. If the ear be applied to one end of a long beam of timber, the Uroke of a pin at the other end becomes fenllble; if a poker be fufpended in the middle of a garter, each end of which is preffeJ againfl: the ear, th~ leafl percuflions on the poker give great founds. And I am informed by laying the ear on the ground the tread of a horfc t;nay be difcerned at a great diflance in the night. The organs of hearing belonging to fi{h are for this reafon much lefs complicated than of quadrupeds, as the [ 175 ] V. "SYLPHS! you, retiring to fequefter'd bowers, Where oft your PRIESTLEY woos your airy powers, 166 fluid they are immerfed info much better conveys its vibrations. And it is probable that fome fh ell- fifl1 which have twitted {hells like the cochlea and femicircular canals of the ears of men and quadrupeds may have no appropriated organ for percetving the vibrations of the element they live in, but may by their fpiral form be in a manner all ear. Wbert oft your Priejllfy. 1. t66. The fame of Dr. Prieftley is known in every part-of the earth where fcience has penetrated. His various difcoveries refpeCting the analyti.s of the atmofpherc, and the produCl.ion of variety of new airs or gaffes, can only be clearly underftood by reading his Experiments on Airs, (3 vols. oClavo, Johnfon, London.) the following aro amongfl: hi many difcoveries. 1. The difcovcry of nitrous and dephlogifl:icated airs. ~. The exhibition of the acids and alkalies in the form of lllir. 3· Afcertaining the purity of refpirable ai.r by nitrous air. ~· The relloration of vitiated air by vegetation. 5· The influence of light to enable vegetables to yielrl pure air. 6. The converfion by means of light of animal an I vegetable fubfl:ances, that would otherwife become putrid and offenGve, into nourifhment of ve~etables. 7· The ufe of rcfpiration by the blood parting with phlogiflon, and imbibing dephlo-giUicated air. The experiments here alluded to are, 1. Concerning the produClion .of nitrous gas from di!Tolving iron and many other metals in nitrous acid, which though firfl: difcovered by Dr. Hab (Static. EIT. Vol. I. p. '1.24-) was fully invefl:igated, and applied to the important purpofe of diUinguifhing the purity of atmof?heric air by J?r. Prie!l:ley. When about two meafures of common air and one of mtroui gas are mtxed together a red effervefccnce takes place, and the two air5 occupy about one fourth lefs fpace thai) was previoufly occupied by the common air alone. . 2. Concerning the green fubfl:ance which grows at the bottom of referv01rs ~f wate:, whicFI Dr. Priefl:ley difcovered to yiclJ much pure air when the fun ili01:e on 1t • . Hts method of colletl:ing this air is by placing over the green fubfrance, :Vhtch l~e behe~es to be a vegetable of the genus conferva, an inverted bell-glafs prevwufly filled w~th water which fubfides as the air arifcs; it has fince been found that all vegetables gtve up pu~c air from their leaves, when the fun {hines upon them, but not in the night, which may be owing to the flecp of the plant. . . . 3 . The third refers to the great quantity of pure :;ur contamcd m the ~alces .of m~tals. The calces were long known to weigh much more than the metal!Jc bodtes before calcination, infomuch that 100 pounds of lead will procij,Jce 112 pounds of |