246 DIADELPHIA DECANDRIA. Butea. 



Sal martis changes the Mateiy solution into a good durable 

 ink. 



These are, 1 think, proofs that a very small proportion of 

 resin is present in this substance. In this it differs essentially 

 from the gum-resin called Kinoov Gummi rvbrum astrin//ens 

 Gambiense, \\ hich the Edinburgh College has taken into their 

 Materia Medica* but as this can be most perfectly dissolv- 

 ed in watery menstruum it mny prove of use, m here a spiri- 

 tuous solution of the former, being the most complete, cannot 

 be so properly administered ; consequently it may prove a 

 valuable acquisition also. I have used the recent gum in 

 making my experiments, which may make some difference. 



Infusions of the flowers, either fresh or dried, dyed cotton 

 cloth, previously impregnated with a solution of alum, or 

 alum and tartar, of a most beautiful brightyellow, which was 

 more or less deep, according to the strength of the infusion. 

 A little alkali added to the infusion, changes it to a deep red- 

 dish orange. It then dyed unprepared cotton cloth of the 

 same colour, which the least acid changes to a yellow, or le- 

 mon. These beautiful colours I have not been able to render 

 perfectly permanent. 



Amongst numberless experiments, I expressed a quantity 

 of the juice of the fresh flowers, which was diluted with alum 

 water, and rendered perfectly clear by depuration. It was 

 then evaporated by the heat of the sun, into a soft extract ; 

 this proves a brighter water colour than any gamboge 1 have 

 met with. It is now one year since I first used it, and it 

 remains bright. 



Infusions of the dried flowers yielded me an extract very 

 little, if any thing, inferior to this last mentioned. They yield 



lutioji of tin in aqua-regia ; but the reds produced thereby were 

 bad ; that where alum was employed, was the best 



* A specimen of the tree which produces this African substance 

 in the Banksian herbarium, convinces me that it is a species of 

 Elceocarpiis. 



