ifi€ Danais of Commerson. 39 



the few experiments which I made, to point out the route 

 to some one more successful who may b\; able to deter- 

 mine the means of employing it. 



Having pullevl up the roots of this plant, I was much 

 surprised to see them of an orange colour, inclining rather 

 to yellow than to red: the rind was pulpy and succulent. 

 Having cleaned them, I put some pieces of it into spirit or 

 rack extracted from the sugar of the country, which in a 

 Jittle time became charged with a tincture of a very pure 

 yellow. When it appeared to me that it had extracted all it 

 could, I poured it into a saucer; the pieces of the root were 

 then of a beautiful red colour : having poured more rack 

 over them, some more particles of yellow were extracted, 

 but it became still redder, and this colour continued un- 

 alterable, tliough I suffered the liquor to Jemain over them 

 several days. What I poured into the saucer having eva- 

 porated, the residuum was of a very beautiful yellow colour. 

 For want of other means, I contented myself with rubbin"- 

 it over paper. Being desirous to try whether a pigment 

 proper for water colours could be extracted from it, I 

 jnixcd it with gum arabic : it spread very well on the paper; 

 I tasted also the extract, it had the bitterness of cinchona 

 in such a degree as gave me reason to hope that it may be 

 rendered of utilitv in this point of view. 



Having tried this root with spirit of wine, I put some of 

 it fresh into pure water. By ebullition the water became 

 charged in like manner with the yellow colouring principle, 

 which it extracted entirely : the root also assumed a red 

 colour, whicli could no longer be attacked by water. One 

 of my friends had given me a small quantity of a solution 

 of tin iii the nitric acid ; I poured a fcvv drops of it into 

 the li(^uor I had obtained, and th.ev precipitated all the 

 colouring parts suspended in it. Having decanted the 

 water, the residuiun was of a beautiful yellow colour: I 

 hoped I should obtain from it a kind of Dutch pink ; I 

 therefore poured more water over it to wash it, but the water, 

 though cold, took up all the colour: nothing then re- 

 mained at the bottom of the vessel but oxide of tin exceed- 

 ingly white. 



I learned at Macbgascar that the process employed by 

 the natives, and probably from time immcraorial, to obtain 

 a red colour, is to boil the root with ashes : I thence pre- 

 fiumcd tliat alkalis were its ^()lvent, but at that time I was 

 unable to procure an\' ; 1 contented myself, therefore, v.ith 

 boiling it in alum ; the two colours were then perce[)tible ; 

 tJie yellow apj>cared first, and then the red : at lirst vtry 

 < 1 hitle 



