CORRESPONDENCE OF RAY. 77 



will cause a violet to strike a green, which is the same 

 effect that an urinous spirit, or an alkali, w^orks. 



I will subjoin the experiment I promised you of the 

 gilding of a chrysalis. To a strong and clear decoction 

 of nettles put a small piece of a black gall, in time there 

 will emerge a thin scum ; if you then pass the liquor 

 through a cap-paper, the scum left behind will exquisitely 

 gild it. The hke I have effected by other methods, and 

 with other plants : if the experiment be well done, it will 

 in all points look like the gilding of the stiff-haired, or 

 prickly-nettle-feeding caterpillar's chrysalis. 



I have not yet seen Redi's book, neither can I get it, 

 though I much desu'c it. It is true that spiders, espe- 

 cially the young ones, are not very shy to shoot their 

 threads, even in one's hand ; and different kinds have 

 many different particularities in this surprising action. 

 As to the height they are able to mount, it is much be- 

 yond that of trees, or even the highest steeples in England. 

 This last October the sky here upon a day was very calm 

 and serene, and I took notice that the air was very full 

 of webs ; I forthwith mounted to the top of the highest 

 steeple in the Minster, and could thence discern them 

 yet exceeding high above me : some that fell, and were 

 entangled upon the pinnacles, I took and found them to 

 be litpi, which kind seldom or never enter houses, and 

 cannot be supposed to have taken their flight from the 

 steeples. 



To tell you the truth, I begun to be at a great loss 

 when I found that my experiments concerning the bleed- 

 ing of the sycamore did not succeed this year as they did 

 the last ; for I assure you, that to this day the two trees I 

 wounded the 1st of November have not shown the least 

 signs of the stirring of any juice, whereas the Notting- 

 hamshire trees had several times bled ere thus late. 



You will be pleased to remember me with a Book of 

 Proverbs, for T long to peruse it. 



York, Jan. 20, 1670. 



