282 AMERICAN SPIDERS AND THEIR SPINNING WORK. 



with the air. I quote his language : " Seeing that the web while it is 

 in the Spider, is a certain cloudy liquor with which that Great bottle 

 tail of theirs is filld which immediately upon its being Exposed to the 

 Air turns to A Dry substance, and Exceedingly Rarifies and extends it 

 self " . . . . " Now if it be a liquor it is hard to Conceive how they 

 should let out a fine Even thread without Expelling a little Drop at the 

 End of it but none such Can be Discerned, but there is no need of this." 

 Young Edwards also perceived that the spider had no direction of its 

 frail aerial vessel after it had once embarked, but was compelled to go 

 at the will of the wind, and to disembark and settle wherever its balloon 

 might find an entanglement. He correctly discerned and explained the 

 theory of equilibrium by which the spider navigates the air. This is 

 his explanation : " If there be not web more than enough Just to Coun- 

 terbalance the gravity of the Spider the spider together with the web 

 will hang in equilibrio neither ascending nor Descending otherwise than 

 as the air moves but if there is so much web that its Greater Rarity Shall 

 more than Equal the Greater Density they will ascend till the Air is so 

 thin that the Spider and web together are Just of an equal weight with 

 so much air." This statement substantially expresses the opinion of all 

 students at the present day. 1 



This review of the studies in natural history of the boy Edwards will 

 suffice to justify the language used nearly sixty years ago by Prof. Ben- 

 jamin Silliman, one of the most eminent of America's men of 

 . . ( science : " The observations recorded by* him present a very curi- 

 ous and interesting proof of philosophic attention in a boy of 

 twelve years, and evince that the rudiments of his great mind 

 were even at that immature age more than beginning to be developed." 

 Even with the more perfect light of the present there will be found few 

 to question the further words of the same distinguished authority, that 

 " had he devoted himself to physical science, he might have added another 

 Newton to the extraordinary age in which he commenced his career ; for 

 his star was just rising as Newton's was going down." 2 



1 See a paper by the author on " Jonathan Edwards as a Naturalist," in Presbyterian and 

 Reformed Review, July, 1890. 



2 American Journal of Sciences and Arts, 1832, page 110. 



