NATURAL HISTORY of N RTFAT. 75 



fcope, and plainly faw it to be a living worm, or annular maggot, 

 confining of eleven wings, like mofl of the larvae, with as many 

 mamillae on the fides inftead of feet, and both at the head and 

 rump, four trunks or feelers (antennae or tentacula.) In the pro- 

 fecution of his refearches, he found that all thefe lucid appearances 

 in the water, arofe from thefe minute and almoft invifible mag- 

 gots ; their whole bodies were lucid, and not fome particular 

 part only, which is the cafe of fome kinds of reptiles ; tho', when 

 at reft, their effulgence was considerably fainter. In fpring thefe 

 luminous animalcula confine themfelves to the fea-grafs, but in 

 fummer they are difperfed all over the fea, and moftly on the fur- 

 face. When thefe nocturnal fcintillations are unufually ftrong and 

 frequent, the flfhermen account it a fure prognoftic of a ftorm, 

 or foul weather ; and this proceeds from the greater agitation of 

 the worms, already fenfible of the approaching changes. This ex- 

 periment puts it beyond all queftion, that the glittering of the fea, 

 in a iliip's courfe, is occasioned by thefe worms; and it is no lefs 

 certain, that they are the caufe of the light in the Penna-marina, 

 (a large mufcle) of which Dr. Shaw writes, that they are fre- 

 quently caught by the Algerine flfhermen ; and in the night their 

 radiations are fo ftrong, that the fifh neareft to them in the 

 net are difcernible without any other light. It were to be wifhed, 

 that the author had been more precife in his defcription of thefe 

 animalcula ; if his eyes may be relied on, one cannot but judge, 

 that they are only a fpecies of the Genus Aphrodite." Thus far 

 this author ; to which all my prefent addition fhall be this ; the 

 Ignes lambentes, or lambent flames, fo well known, which by 

 their hovering about the mips rigging, and often fettling on the 

 mafts, tho' without doing any damage, ftrike a terror into the 

 feamen; and likewife thofe Ignes fatui, or jack-a-lanthorns, which 

 deceive the traveller by land, muft, according to this principle, be 

 no more than worms, bred in the above-mentioned fulphureous 

 oil, with which both land and fea is filled, but which is too fub- 

 tile to be difcerned by day, when even the light of the ftars is 

 feemingly invifible. 



Part L X SECT, 



