Papuan Tliinhers. 



35 



ceased to be visible in twenty minutes. Tlie process was com- 

 plete in forty minutes, when the gas Avas turned off, and the 

 specimens allowed to cool. They were then removed from the 

 furnace, and again weighed, and the percentage of charcoal 

 ascertained. The following Table 6 shoAvs the total weight of 

 the cubes before being dried, the percentage of moisture eva- 

 porated during drying, the weight after being dried, the weight 

 of charcoal produced, and the percentage of charcoal calculated 

 from the dry weio-ht of the wood. All weio-hts are in grains. 



Table 6. 



\Vt. Charcoal. 



237.40 



Per c. of 

 Charcoal 



33.77 

 21.07 

 27.88 

 24.06 

 25.14 

 24.21 



Drj weight. 



702.80 - 



501.00 - 105.60 



413.80 - 115.38 



369.00 - 88.80 



341.60 - 85.88 



258.10 - 62.65 

 Tliis may be considered rapid carbonisation. The tempera- 

 ture was about 700 deg. F. 



Percentage of Ash. 



TTie same timbers, in fact, cubes adjoining those treated for 

 charcoal, were prepared in the same manner, and submitted 

 to a similar process, except that the specimens were placed in 

 porcelain crucibles, in an open furnace. The combustion was 

 complete in every ca.se, and the succeeding table gives the 

 amount and percentage of ash obtained : — 



Table 7. 



Each set of experiments is given in the schedule of details. 



From the above two tables (6 and 7) it will be seen what 

 quantity of charcoal and ash can be obtained from any 

 given weight of dry wood, and also the proportion of volatile 

 matter given off during combustion. It must be remembered, 



