l6o ■ Defcription nj the Urceola ElaJ^ica. 



wine, confequently remained obftinately united to the for- 

 mer, wliich prevented its being brought into that ftate of 

 firmnefs fit for h.mdling, which it acquired when Cajeput 

 oil was tlie menftruum. 



The Cajepnt folution employed as a varnifli did not dry, 

 but remained moill and clammv, whereas the turpentine 

 fokition dried pretty fali. 



Expreffed oil of olives and liufced proved imperfecl trien- 

 ftruums while cold, as the Caout-chouc, in feveral days, was 

 only rendered foft, and the oils vifcid, but with a degree o\ 

 heat equal to that which melts tin, continued for about 

 twenty-five minutes, it was pcrfeftly diffalved, but the lolu- 

 tion remained thin, and void of elafiicity. I alfo found it 

 foluble in wax and in butter in the fame degree of heat; bul 

 Hill thefe folutions were without elaiticity, or any appearance 

 of being ufeful. 



I fhall now conclude what I have to offer on the Caout- 

 choucy or Urceola elajUca, with obferving, that fome philo- 

 fophers of eminence have entertained doubts of the Ame- 

 rican Caout-chouc being a fimplc vegetable fubftance, and 

 fufpcft it to be an artificial production ; an idea which I 

 hope the above detailed experiments will help to eradicate, 

 and confequently, to rertore the hiftories of that fubftance by 

 M. De la Condamine and others, to that degree of credit 

 to which they feem juftly entitled ; in fupport of which it 

 may be further obferved, that, bcfides Urceola elajlica, there 

 are many other trees, natives of the torrid zone, that yield 

 a milky juice, poflcffing qualities nearly of the lame nature, 

 as artocarpus inhgrijolia (common- jack tvec), fields rcligjojhs 

 et Jndtca, H'lppojiiane biglandulofa, Cccropia peltata, 8cc. 

 • The Caout-chouc, or F'lcus rcligiofa, the Hindus confider 

 the moft tenacious vegetable juice they are actpiainted with ; 

 from it their beft bird-lime is prepared. I have examined 

 its qualities, as well as thofe of ficus Ind'ica and artocarpus 

 intcgrif'ollay bv experiments fimilar to thofe above related, 

 and found them triflingly eladic when compared with the 

 American and Urceola Caout-choncs, but infinitely more 

 vifcid than either; they are alfo inflammable, though in a 

 lefs degree, and lliow ncarlv the fame phenomena when 



inimcrftd 



