234" EXPERIMENTS ON GUM KINO. 



in hot water, and gives it a fine red colour. It is precipitabfe 



by alcohol; but neither by glue, nor by any metallic folution. 



On burning, it difrufes a fmell refembling that of gum. 



This favours the I fufpeft the prefence of this fubftance favours the folution 



folurion of the j,^ water of the principle foluble in alcohol; for the latter is 



jn water. lefs foluble in water when feparated from the former; and, if 



the quantity of water necelTary for diflblving the aftringent part 



be not employed in the firll inflance, what is left requires a 



I greater proportion of water. 



Water diflblves Four litres of water, ufed at different times, left near 



|, twenty grammes out of a hundred of kino undiflblved. The 



alcohol moft of refiduum grew foftlike a refin in boiling water, and all of it, 



except feven decigrammes, was foluble by 'alcohol, to which 



it imparted all the properties before obferved in the aftringent 



matter. 



Sulphuric acid Sulphuric acid diminidies the adion of water on kino, in- 



renders it Icfs flead of increafinff it, as it does with refpeft to the refinous 

 foluble. . r ■ , 



part or cmchona. 



It tans leather. It is capable of being ufed for tanning leather. 

 Neither a gum, From what has been faid it appears, that the greater part 

 noragum -vefin, ^f j^jj^q confifls of tannin, and is neither a gum, nor a gum- 

 but chiefly a . T^ , . „■ , i-r,' 1 . , , 



fpecies of tan- refin. But there is a flight diiierence between it and the tan- 

 "'"• nin of galls and oak bark, which precipitate iron of a blue 



black, while kino precipitates it green, in which it refembles 

 cinchona and rhubarb. If therefore it were to become plen- 

 tiful and cheap, it might be employed for all the purpofes fof 

 which aflringent vegetables are commonly ufed. 



Addition. 



Dr. Duncan ^''* Vauquelin is not the firft who difcovered the common 



firft aflerted it error refpecling kino. In the new Edinburgh Difpenfatory, 



to be an extraft. jy^ Duncan has entered pretty fully into the fubjeft, and afierts 



it to be in reality an extraQ. He adds, that what we have 



now in the fliops is not brought from Africa, but chiefly from 



Obtained from Jamaica. In a private letter he informs me, that this is an 



crape^^ * ^ cxtradl of the coccoloba urifera, or fea-fide grape ; while the 



fineftkino of the fliops, and what from fome circumftances he 



fuppofes was the fort analyzed by Vauquelin, is the product of 



and gum-tree of different fpecies of eucalyptus, particularly the refinifern, or 



Botany Bay. jj^own gum tree of Botany Bay, from which country a parcel 



was imported fome years ago. 



W. N. 

 IV. Extrad 



