1822.] Chemical Examination of Spiders' Web. 11 



G, and that the action of the wind moved the hands four turns 



and 76 divisions. 



4 turns = 11-6012 



2-1578 X 76 = 1-6399 



Momentum in lbs 13-2411 



Example 2. — Suppose one ounce suspended to the cord, and 

 that the wind moved the hand 60 divisions. 100 — 60 = 40 ; 

 •0341 X 40 = -0136. 



1 turn = 0-1972 



Subtract 0-0136 



Momentum 0-1836 lbs. 



Article III. 



Chemical Examination of Spiders' Web. 

 (To the Editor of the Annals of Philosophy .) 



RESPECTED FRIEND, Manchester, Eleventh Month, 20, iS2\. 



Happening a short time ago to apply the flame of a candle 

 to a collection of spider's web, my attention was excited by the 

 formation of a large quantity of dense white vapours which 

 ascended during the combustion. It struck me that the pheno- 

 menon was probably occasioned by a volatile salt. 



The following particulars are all which I have yet ascertained : 

 I purpose to resume the inquiry ; and if any facts of interest 

 should present themselves, I shall again trouble thee with a 

 communication on the subject. I find that all webs have not 

 precisely the same properties. Those specimens which I pro- 

 cured from a moist dark vault, differ from others obtained from 

 lighter and more airy situations. The former, by the addition of 

 cold water, afford a deep-brown coloured solution ; while the 

 latter gave only a tint of yellow. By an application of the 

 necessary tests, 1 find that the webs v/hich 1 have examined 

 contain lime, together with muri{;i(tic and sulphuric acids. A part 

 of the first of the cold water solutions, just mentioned, was 

 boiled in a flask ; when the water had evaporated, the residuum 

 emitted a very offensive smell, resembling that of animal matter 

 when cast upon hot iron. When the heat was continued, there 

 arose copious white fumes. The matter remaining, after the last 

 operation, was of a brown colour. To this matter, when the 

 vessel had cooled, a quantity of fresh water was added; the 

 SQlution was then allowed to boil for a few minutes. The water 



