THE TIMBERS OF COMMERCE 



then very definite and clear with the lens, but they display no 

 harmony with the arrangement of the pores. 



Sojt-tissue. Abundant in concentric lines, about 120 per 

 inch : size equal to 4 (ray scale) : contour weak : otherwise well- 

 rounded : cells coarse, equal to size 6 (pore scale) : brown : very 

 distinct and characteristic in the transparent section, though 

 sometimes reduced to vanishing point. 



Radial Section. Pores prominent though rare, usually dull 

 often with shining drops : rays minute, dull flakes or lines : 

 difficult to see : light coloured. Soft-tissue visible' as fine, 

 whitish lines very close together. 



Tangential Section. As the Radial, but the pores are much 

 finer as they are cut through the narrow way. Rays minute, 

 whitish lines upon the limit of vision about o'l mm. high. Soft- 

 tissue not so coarse or close together. 



Type specimen authenticated by the Forest Officer to the 

 Government of British Guiana. 



The structure of this wood agrees closely with that of Parina- 

 rium Nonda, but as the specimen was not accompanied by its 

 systematic name I cannot vouch for more than the genus. 



No. 87. Pygeum africanum. Hook. 



Plate VII. Fig. 58. 



Natural Order. Rosaceae. 



Source of Supply. South Africa. 



Physical Characters, etc. Recorded dry-weight 57} lbs. per 

 cu. ft. Hardness Grade 5, compare English Elm. " Smell or 

 taste none. Burns well and quietly : an orange-coloured juice 

 is expelled by heat : embers glow in still air : no aroma. Solu- 

 tion colourless : a copious red ppt. with potash. Neither water 

 nor alcohol will completely bleach the wood. In order to do this 

 it needs to be boiled in potash. 



Bark. ? There is a thin, scaly, chocolate-brown skin about 

 ? V inch thick upon the outside of my specimen which may be 

 the bark or only an inner layer. 



A wood of fine texture which planes and saws exceptionally 

 smoothly and well. 



Colour. Uniform red passing gradually over into the light 

 brown sap-wood, which is about 4 inches wide. 



Anatomical Characters. Transverse section : — 



Pores. Visible, size 4-5, little variation : uniformly scattered, 

 single or in small radial sub-divided groups of 2-4 between the 

 rays : 10-25 per sq. mm. 



Rays. Need lens or just visible, size 5-6, uniform though 

 apparently of two sizes : stout, tapering rapidly to fine threads 



102 



