300 Timehri. 



hardens the sap wood, which naturally hurries the drying-up process. As 

 wood shrinks when it dries it is natural for the ends to contract trans- 

 versely, and as the centre portion is still moist it cannot follow the pres- 

 sure, so the consequent tension causes the trouble. 



It is advisable and safe when sawing gTeenheart for export to 

 increase dimensions by |" for the subsequent contraction. 



Greenheart turns and machine dresses well. 



Purplehe art ( Copaifera). 



Purpleheart is graded as a fairly hard wood and is useful for all 

 ] imposes where shock has to be resisted. Purpleheart has been used 

 with success as a bed for the mortar box of a stamp mill of a now defunct 

 gold mine in the colony. 



Newly sawn boards rapidly become purple on exposure to sunlight 

 and appear cured owing to the beautiful rich purple colour on the 

 exposed surface only. Cured purpleheart boards after developing high 

 colour in diffused light commence to fade after some months. Likewise 

 do cured boards lose their colour if dressed, only to again recover it with 

 the same process of fading as before described 



Suradaxi (Hieronyma Laxiflora) and Mora (Dimorpliandra Mora). 

 In appearance these woods are somewhat alike. As they are tough 

 and cross-grained woods they sometimes give trouble during conversion 

 if not handled in the right way. 



Like bulletwood, they exude a peculiar gummy substance which 

 crusts on the saw teeth ; this causes sticking and with the friction set 

 up the set is easily taken out of the saw. 



The modulus of rupture of mora is 14,644 lbs. per square inch as 

 against 11,800 lbs. for pine, so it is quite unnecessary to have a sleeper 

 ot the same dimensions as that of pine or of such as obtains in practice 

 of railway construction. Being a stronger, heavier and more durable 

 timber than pine it cannot compete on favourable terms if sleepers of 

 similar size have to be supplied for the reason that it is far more difficult 

 to saw. 



As mora is eminently suited for railway sleepers I have particularly 

 referred to it at this point. 



Sawn mora sleepers have been fcund, in actual practice, to be more 

 durable than those of hewn timber. The dimensions of a sleeper are 

 such that ii' required hewn suppliers in the interior would furnish mere 

 saplings. It is true that only mature timber for sleepers should be 

 demanded from suppliers and this will necessitate the felling of huge 

 trees which would eventually have to be hewn down to size, so it would 

 be more economical to have sleepers sawn. 



Wallaba (Epcrua Falcate). 

 This wood splits very easily and cleanly but soon becomes dis- 

 agreeably sticky on account of the resinous substance it exudes. Sawn 



