£1 Mr, Adams on [Jan. 



had by this means no colour imparted to it ; but, when tested 

 with hydrochlorate of baryta, a precipitate was instantly occa- 

 sioned. Oxalate of ammonia produced a precipitate ; but nitrate 

 of silver had not the least effect. Some of the first mentioned 

 residuum, after having been well washed, was heated to redness 

 in a silver spoon ; there remained a greyish coloured earth, but it 

 was not in sufficient quantity to enable me to ascertain its pro- 

 perties. It is not improbable, I imagine, that the white fumes 

 were occasioned by muriate of ammonia ; and this conjecture is 

 countenanced by the circumstance, that if water be added to the 

 residuum, no precipitate is produced by nitrate of silver. 



An accurate analysis of the spider's-web might lead to some 

 results interesting alike to the chemist, and to the student of 

 natural history. 



I remain, thine very truly, O. S. 



P. S. I might also add, that subsequently to writing the pre- 

 ceding statement, I made a quantity of the web into a paste with 

 warm water; I then mixed it with a paste formed of warm water 

 and hydrate of lime, when I found an immediate evolution of 

 ammoniacal gas, confirming my conjecture as to the presence of 

 muriate of ammonia. 



Article IV. 



Rules and Examples for the perpetual Renewal of Leases. 

 By Mr. James Adams. 



(To the Editor of the Annals of Vhilosophii ,) 



SIR, StotieJiouse, near Plymouth, Oct. 1 1 , 1821 . 



Having often had occasion to calculate the value of lease- 

 hold property held on perpetual renewals, I deduced the follow- 

 ing particular rules from the more general ones given by the 

 writers on Life Annuities, and having found them useful to 

 myself, I judge that they may be useful to others who have 

 similar calculations to make. Your inserting them with the 

 following examples, Sec. in the Annals of Philosophijj will oblige 



Your humble servant, 



Jame^Adams. 



A lord of a manor grants to a tenant a piece of land on condi- 

 tion that he builds on a certain part of it a substantial dwelling 

 house and appendages, for which the tenant is to have a lease 

 on three of the best lives he can find, and that he and his suc- 

 cessors shall be allowed to fill up the lease continually whenever 



