THE AERONAUTIC OR BALLOONING HABIT. 



281 



i 



which record the letter of the English correspondent was probably con- 

 structed. 



Young Edwards appears to have made a rude division of various tribes 

 of spiders, which, as far as it goes, is accurate, at least sufficiently so for 

 all popular purposes. In a general way this lad as early as A. D. 1716 

 had hit upon the foundation principle of classification of the distinguished 

 naturalist Latreille, who, just a century later, divided si)idors into seven 

 groups, based upon those very habits which young Edwards notes, al- 

 though, of course, with more careful characterization.^ 



Edwards had found that on a dewy morning towards the end of Au- 

 gust or beginning of September one has the best opportunity to study 

 field spider webs. He had further discovered that spider webs which are 

 ordinarily unobserved may readily be brought into view by putting one's 

 self into such position that the rays of the sun shall fall 

 upon them against some opaque body. 



Once more, the boy naturalist had discovered that the aero- 

 nautic habit of spiders is closely associated with those Ijridge 

 lines which are continually observed in summer stretched from 

 tree to tree across roads, l)etween fences, and in like j)osition. 



Again, he appears to have discovered that the spider, while 



engaged in casting out these bridge lines, often swings itself 



in a little basket of lines held between the bunched 



Swingmg £gg^_ j ]^g^^yQ particularly alluded to this in Volume 



■R ij. f I-, P'lge 69, when speaking of the use of what I have 



called the swinging foot basket, a .. 



habit of which I had supposed that I was the / *?' * 

 original discoverer. The drawing in Volume L, 

 Fig. 65, was taken from what I supposed to Ije 

 an accurate fac simile in " Silliman's Journal ; " 

 but, in point of fact, Edwards' drawings, as 

 given by Professor Smytli, are far more accu- 

 rate than those, particularly in the outline of 

 the spider's body and legs, and I therefore re- 

 produce them here, after the drawings in the 

 "Andover Review." 



Again, Edwards defined correctly the manner in which the spider's 

 thread is formed. He could make no studies of the interior structure 

 of the animal. It was reserved for the age of the microscope 

 ,. .. ' to do this, but this boy of thirteen years old reasoned that the 

 spinning stuff must be contained in liquid forna within certain 

 appropriate organs in the abdomen, from which it is expressed, escaping 

 from the spinnerets as a liquid, and immediately hardening by contact 



Fig. 281. Edwards' Ballooning Spiders. 1, 

 dropping from twig; 2, swinging from 

 line ; .3, sending out threads, b e ; 4, a, 

 abandoned thread ; c b, spider in flight. 



' See Cuvier's " Le Regne Animal," edition 1817, Paris. 



