58 CORRESPONDENCE OP RAY. 



seem to fly. Mostly they project their threads single, 

 without any dividing or forking at all to be seen in them. 

 Sometimes they will shoot their threads upward, and will 

 mount up with them in a line almost perpendicular; and 

 at other times they project them in a line parallel to the 

 plane of the horizon, as you may often see by their 

 threads that run from one tree to another, and likewise 

 in chambers from one wall to another. I confess this 

 observation at first made me think they could fly, because 

 I could not conceive how a thread should be drawn pa- 

 rallel between walls, as above-said, unless the spider flew 

 through the air in a straight line. The way of forking 

 / their threads may be expressed by 

 / the following figure. What reason 

 should be given of this dividing I 

 know not, except that their threads, 

 being thus winged, become able to sustain them in the 

 air. They will often fasten their threads in several places 

 to the things they creep up : the manner is by beating 

 their bums, or tails, against them as they creep along. 

 This line will express the way : 



\ 



By this frequent beating in of their thread among the 

 asperities of the place where they creep, they either secure 

 it against the wind, that it is not so easily blown away, 

 or else whilst they hang by it, if one stitch break, another 

 holds fast ; so that they do not fall to the ground. There 

 is another thing 1 have to deliver about these webs, but 

 as yet I am in some doubts about it ; and therefore at 

 present I shall remain. 

 June 28, 70. 



NOTE .Notwithstanding this letter of Dr. Hulse was 

 published by Mr. Oldenburgh from Mr. Wray, in Phil. 

 Trans., No. 65, yet I think fit to reprint it, that the 

 reader may have all the original letters relating to the 



