Y2. eif TtffttL. 



Taftcandfmell Its taft« is intolerably hot, and preciWy fimilar to that of 



itrong, and that ^ r • '^ /- n 



of ihf pepper. P^PP^"^- So is Its fmell. 



corn. When heated to 100®, it foftens; it melts at 148'', evapo- 



Iilfli'able. '^^^^ ^ ^'^^'^ ®^^^^ 212° in a white fraoke, which fmells like 

 tobacco fmoke, irritating the throat and exciting coughing. 

 Evaporated to drynefs on a glafs plate, it leaves a yellow trace 

 behind it. When fuddenly heated, it boils violently, and the 

 Vapour burns with a clear white flame without any fmoke. 



Volatile by jt gives agreafy (lain of a green colour to paper. At 500° 



the greafy appearance is removed, but the green mark fiill con- 

 tinues, unlefs the heat be fufficient to char the paper. Hence 

 I think it follows, that the colouring matter of this oil is a fub- 

 flance entirely diflinfi from the oil itfelf. 



Soluble in alco- fhe oil of pepper is infoluble in water; alcohol and ether 



hoi and in ether, ,.». , . i-i ,i r i • • i- , . ■ , > , ,• 



but notinw-iter, a»"^ive it readjly; the lolution is light green: alcohol holding 



&c. it in folutipn, acquires a very fragrant odour, precifely iimila.' 



to that of oil of lavender. When water is added to this folu- 



tion, the whole becomes milky, and pafles in that (iate through 



the filter. On /landing fome weeks, light green flakes fubfide, 



but the milky opacity is permanent. 



Aaionofal- Alkalies have no fenfible a6lion on this oil while cold, 



icalis* 



When thrown into liquid potafti it fwiras on liie furface. If 



the liquid be heated, the oil becomes brown and acquires 



greater confiftence. At the fame time it evaporates partially, 



diffufing around the peculiar odour of pepper. 



•-- of nitric acid. Nitric acid difiblves it with effervefcence, the folntion is yel- 



lowifh browri, and a waxy matter (wims on Uie furface. This 



acid 2t^-< in the fame manner on other volatile oils. 



— and of ox. The oXygenij?ed mqriatic acid dertroys the green colour and 



mur. acid. ^^akes it yellowifl) white. But it ftill retains its former taHe. 



It is a vol. oil Tliefe properties are fufficient to authorize us to refier this 



with col. natter green m^^tter to the genus of volatile oils It is not however 



*^ ^^ "* a pure oil, for befiJes the colouring matter already mentioned, 



it obvioufly contains a fubftance which approaches to thegenus' 



of refins in its properties. 



Bstr-'iSii'dt ai IV. The EXTRACTIVE of pepper is j>rocured by ipacerat- 



P-PP-<^» ing ({,e pepper-corns in cold water. Like the other fpecieu of 



this difhcult genus of vegetable principles, it is fcarce poffible 



to ob'ain it in a ftate of ablolute purity. But if we macerate 



the pepper-torns whole in fucceffive portions of water, till the 



liquid Ipfes the peppery flavour, and then pour on them frefli 



i 4 water, 



