NATURAL HISTORY of NORWAY. 



account for it, and nothing of this kind is found even in the Ada 

 Societatis Hafnienfis, T. I. No. IX. and T. III. N°. VI. where it 

 might mofl naturally be expected, as thefe pieces contain hiftori- 

 cal and phyfical accounts of this very light, with feveral plates, 

 reprefenting the obfervations made in many parts of Europe, on 

 the various figures of the northern lights. In the year 1741, the 

 fon of Capt. Heitman, another great naturalift of Norway, pub- 

 limed a pofthumous piece of his father's, on the heat of the fun, 

 &c. and likewife on the north-light. His fyftem of the means 

 and manner by which the fun influences our earth, and the other 

 planets, at fuch an immenfe diftance, through the ethereal ex- 

 panfe, is certainly very ingenious, but I am cautious of fubfcrib- 

 ing to it, as it oppofes the doctrines of Newton, Wolfius, Rein- 

 beck, and other eminent mathematicians; yet his thoughts on 

 the north-light, as he was both a perfon of great erudition and 

 experience in philofophy, deferve to be here inferted along with 

 other conje&ures, eipecially as he there treats of another pheno- 

 menon analogous to it, namely, a fea-light, or a luminous ap- 

 pearance in the water, called by the Norwegians, Moor-Ild. His 

 fentiments on both thefe fubjects are as follows: " Thus it is ob- 

 ferved in the frigid zone, that the force which gives motion to 

 the high winds, is there at its utmoft height; infomuch, that 

 fometimes the lower region of the air, which is filled with nitrous 

 vapours, is whirled round, and then is formed that light in the 

 air called the Aurora borealis, or north-light : yet this is a light 

 void of heat, and of the fame nature with that light which the 

 people of Norway call Moor-Ild, and takes its rife nearly from 

 the fame caufe as the Moor-Ild, the latter proceeding from an 

 apitation of the falt-water in a dark night, which hath been 

 every year obferved by the herring-fifhermen, when towing their 

 nets along in a calm; for the fea appears in a kind of flame, as 

 far as the nets reach, whereas before the motion of the nets, not 

 the leaft glimpfe of light was difcernible. In frefh-water lakes, 

 there is no fuch flame apparent; it being formed by the faline 

 particles, which upon a motion of the fea begin to fparkle, and 

 caufe an effulgence *. The fame has been likewife obferved in 



* This fparkling fire in the fea, fliall be treated of more at large in chap. 3. fed. 8. 

 when we come to treat of the fea, to which it properly relates. 



C navi- 



