L I G 



I. I G 



■parviflora ; Berg-. Cap. 345'.) — Leaves plain, ovato-laneeo- 

 late, alternate, reflexetl. Stigma tlu-ee-clch. Corolla 

 wiilely fpreading. — Native of the Cape of Good Hope, as 

 are the two following fpecies alfo. This was fent to Kew 

 ill 17S7, by Mr. F. MafTon. ft 13 kept in the greenhonfe, 

 and flowers from July to S''ptember. The^ro; is perennial, 

 fliriibby, of humble growtli, bufhy and ipreading, not prof- 

 trate, very much branched, often finely dawny. Leaves 

 mimerous, fmal', alternate, fefTile, rellexed, ovate or iome- 

 what lanceolate, acute, fmooth, thick-edged, entire, except 

 a fmall glandular tooth or two at each fide. Fiotvers (mM, 

 on little, terminal, naked, fimple flalks. Corolla white, with 

 a tinge of purple along the middle of each fegment. 

 Sli^ma purple. Capfule of three pointed valves forming a 

 cone. 



1. L. temlla. Curve-leaved Lightfootia. (Campanula 

 tenclla; Linn. Suppl. 141.) — I.,eaves ovato-lanceolate, chan- 

 nelled, cluftered, recurved. Stigma three-cleft. Corolla 

 ^videIy fpreading, with narrow linear fogments. Stigma 

 three-cleft. Gathered by Thunbcrg at tlie Cape. It fecras 

 a Ih-ar.ger to our gardens. L'Heritier confounded it with 

 the preceding, from which it differs in its very numerous, cluf- 

 tered, recurved, and deeply channelled kav.s, and the longer 

 and narro'.ver fegments of the corolla. We cannot but think 

 it more than a variety, though there is fcarcely any difference 

 befides what we have mentioned. 



5. la.Jubuhta. Awl-leaved Lightfootia. L'Herit. Sert. 

 Angl. 4. t. J. — Leaves awl-fhaped. Calyx ahnolt altoge- 

 ther inferior. Corolla moderately fpreading, with linear 

 fegments. Stigma five-cleft.— Sent to Kew by Mr. Maflbn 

 in 1787, from the Cape. — This is diftinguifned bv its co- 

 pious, awl-fiiaped, very narrow haves, fometimes near an 

 inch long. The lhrubby_y?';ff;, with downy branches, accords 

 nearly with tin two former. The flowers (land on ihorter 

 italks, and have longer (liarper calyx leaves, tumid at the bafe, 

 and almcil perfeftiy inferior. Segnu-nts of the corolla mo- 

 derately fpreading, recurved, narrow, white or blueifh. 

 Stigma five-cleft. Capfule we prefume of five valves. 



Nothing can agree more exaftly with this as to habit than 

 Campanula paniculata, Linn. Suppl. i:;q, and Trachel'mm 

 d'iffufum, 14;; ; but their corolla has a long tube. The cap- 

 fule of this fuppofcd Campanula has 'i\sz vnlves opening at 

 the top, exaftly as in Lightfootia, not by pores laterally, and 

 the calyx is half fuperior, fo that it certauily belongs to the 

 fame genus, the length of the tube of the corolla being of 

 much lefs importance. 



LiGiiTFOOTiA is alfo the name of an arborefcent geniis 

 of the Pahanrlria Monogynin, in Swartz's Fl. Ind. Occ. 

 V. 2. 947, referred to Prockia in Willd. Sp. PI. v. i. 12 14. 

 Thi^ is Lightfootia of Mart. Mill. Dift. v. 3. 

 LIGH TNESS. See Levity. 



LIGHTNING, in Phyfn^ogy, is a large bright flame, 

 darting fwiftly tlirough the air, and extending every way to a 

 confiderable dillance, of inomentary duration, and commonly 

 attended with thunder. Some have accounted for tliis 

 phenomenon bv fuppofing, that, from the particles of ful- 

 plnir, nitre, and other combuftible matter, which are ex- 

 iialed from the earth, and carried into the higher regions of 

 the atmofphcre, is form.ed an inflammable fubitancc, which, 

 when a fufiicient quantity of fiery particles is feparated 

 from the vapour buoyed up into the air, with thefe particles 

 adhering to them by the coUifion of two clouds or other. 

 ■wife, takes fire, and flioots out into a train of light, larger 

 or lefs, according to the ilrength and quantity of the mate- 

 rials. 0;hers have cxjiained lightning by the fermentation 

 of fulphureous iubilances with nitrous acid? : fee Thunder. 

 But in the prefent advanced .'late of the icience of tleftri- 

 Vol.. XXL 



city, this i.s univerfally allowed to be iin eledrical phenom". 

 non. Philofopiicrs had not proce-dcd far in their experi- 

 ments and inquiries on thi.s iubjeft, before they were ilruck 

 with the obvious anaiogy between lightning and eieftricitv, 

 and they produced many arguments, a priori, to afcertain 

 tiicir fimilarity. I'mt the method of verifying this hypo- 

 tliefis was firlt propofcd by Dr. Franklin, who, towards 

 the clofc of the year 1749, conceived the practicability of 

 drawing lightning from the clouds: having fo.ind, bv prc\ii;i:s 

 experim.cnts, that the electric fluid is attradtcd bv points, \\c. 

 apprehended, that lightning might hkewife pollefs the fame- 

 property ; though the.cffi cts of the latter muft, in an afto- 

 iiilhing degree, fur])ars thofe of the forrrer. The other 

 circuniftancts of refemblance between lightning and elec- 

 tricity remarked by this ingenious pliilofopher, and abun- 

 dantly confirmed by later difcovenes, are ti.e following: 

 flafhcs of lightning, lie obferved, are generally feen crooked 

 and waving in the air ; and the eleftric fpark drawn from 

 an irregular body at fome diilance, and wlien it is dr.iwn bv" 

 an irregular body, or through a fpace in which the l>eft con- 

 duftors are difpoltd iu an irregular manner, always exhibits 

 the fame appearance. 



Lightning llnkes the h'ghcll; and moft poiufcd ob;cas \\ 

 its way, preferable to others, as high hiOs, trees,' fpires, 

 mails of fliips, &c. and all pointed conduclors receive and 

 throw off the eled'tric fluid more readily than thofe which are 

 terminated by flat furfaces. Lightning is obferved to take 

 the readiell and beil condiiclor ; and this is tlie cafe with 

 electricity in the difcharge of the Leyden phial ; v hence 

 the dodor infers, that in avhurdcr llorin, it would be fafcr 

 to have one's clothes wet than dry. Lightning burns, dif- 

 folves metals, (fee Fu.siON,'! rends fome bodies, has been often 

 known to flrike people blind, dcllroys anim.Tl life, dcpi;ive$ 

 magnets of tlKi:- virtue, and reverfes their poles ; and tiiefe 

 are well-known properties of eleclricitv. 



Lightning not only gives polarity to the magnetic needle, 

 but to all bodies that have any thing of iron in them, as 

 brick, &c. ; ami by obferving v.-hicii. way the poles of thefe 

 bodies lie, it may be known, witli the utmoll certainty, in 

 what diredlion the flroke jiaded. Kignior licccaria fuppules, 

 that pcrfons are fometimes killed by l-ghtning, witiiottt beinti- 

 really touclicd by it ; a vacuum t)f air only being fuddenfy 

 made near them, and the air rnfiiing out of their lungs to 

 fupply it ; and with fo much violence that they could never 

 recover their breath. In proof of this opinion he alleges, 

 that the lungs of fuch perfons are found flaccid ; whereas, 

 when they are properly kihed by the eledrical fhock, the 

 lungs are found inflated : but this hypothelis is controverted 

 by Dr. Priellley. In order to denionilrate the identity of 

 the eleflric fluid with the matter of lightning, by r.clual' ex- 

 periment. Dr. Franklin contrived to br'hig lightnincr from 

 the heavens, by means of an eleclric kite, whtcii lie railed, 

 when a florm of thunder was perceived to be coming on ; 

 and with the eledricity thus obtained, he charged phials, 

 kindled fpirits, and performed all other electrical experir 

 ments, which are ufually exhibited by an excited globe or 

 tube. This happened in .lune, 1752, a month after the 

 eleftricians in France, of v.-hom the moil aftive were MefTrs. 

 Dalibard and Delor, followed bv Mr. Mazeas and M. Mon- 

 nier, purfuing tlie method which he had propofid, had 

 verified the fame theory ; but witiiout any knowledo-e of 

 what they had done. In April and .lune, 1755, In: dif- 

 covered that the air wss fometimes eledrificd politivelv, and 

 fometimes negatively ; and found that tlie clouds would 

 change from pofilive to negative electricity feveral times in 

 the courfe of one thuiuler-guil. He foon perceived that this 

 important difcovery was capable of being applied to practical 



C nlc. 



