1888-89.] Wood of certahi Resin-Producing Trees. 385 



3. Partially soluble in warm benzole. 



4. Do. in warm chloroform. 



5. Insoluble in olive oil. 



6. Soluble in acetone. 



It has the properties of ordinary medicinal guaiacum resin 

 as to acid and soda reactions. The tincture, spread on blot- 

 ting paper and held over chlorine or bromine water, or 

 nitric acid, gives at once a splendid deep blue. This colour 

 is also got by adding a drop of ferric chloride to the tincture. 

 The colours disappear rapidly in excess of reagents, so that 

 they must be applied cautiously. 



The alcohol resin has a rather darker appearance than the 

 ether one. It is evidently the same body obtained in small 

 quantity, on account of the higher boiling point of the spirit 

 enabling it to act more searchingly on the fibre of the wood. 

 The alcohol resin gives a black with sulphuric and a greenish- 

 black with nitric acid at once. 



PuEPLE Heart — Copaifera Martii. — This wood appears 

 to have been first imported into England in the decade 

 1820-30. The tree is a large one, the wood being hard 

 and strong, but containing a compartively small proportion 

 of resinous matter. It is not very easily dressed, being what 

 workmen call stringy. Its peculiar colour had plainly at 

 once attracted notice in England, for soon after its introduc- 

 tion it was employed for parquetry floors at Windsor Castle, 

 Buckingham Palace, and other important buildings. 



A remarkable property of this wood is its behaviour when 

 exposed to light after being freshly cut. It has an unattrac- 

 tive brown colour when newly split and newly planed, but 

 unless kept in the dark, it becomes, sometimes in the course 

 of a few hours, at other times after the exposure of a day or 

 two, of a fine purple colour. This is no doubt caused by 

 the oxidation of its resinous colouring matter. Experienced 

 cabinetmakers say that the purple colom- is fairly permanent. 

 It does, however, sometimes alter in the course of years. But 

 even if it becomes dingy, a slight paring of the surface will 

 serve to restore the colour. 



The " purple heart " appears to be one of the trees which 

 yields balsam of copaiba. It is a native of British Guiana 

 and North Brazil. It is there used for constructive purposes, 



