406 B. T. Patton : 



on blocks on a table so that there was a free supply of air on all 

 sides. The following table shows the results. Weights are expressed 

 ^s percentages of the original weight. 



Date. 



Weight of 

 Upright Beam. 



% 



Weight of 

 Horizontal Beam. 



% 



21.6.18 



100 



100 



1.7.18 



93.0 



92.0 



12.8.18 



82.2 



81.3 



9.9.18 



77.8 



77.0 



8.10.18 



75.3 



73.9 



7.11.18 



71.6 



70.8 



It will be seen that the horizontal beam has slightly the advan- 

 tage in the rate of drying. Timber loses its moisture by diffusion 

 through the sides of the timber, and therefore it does not matter 

 how the timber be stacked provided there is a free supply of air 

 all round it. The question was further tested by suspending a 

 beam of 4 in. x 3 in. from the ceiling of the laboratory and taking 

 the moisture content of the top and bottom of the beam each 

 month. The result is as follows : — 



Date. 



Moisture Upper 

 o/ 



Etid. 



Moisture Lower End. 



o/ 



27.6.18 



% 



47.2 





% 



46.4 



10.7.18 



45.3 





.. 45.9 



12.8.18 



35.6 





36.0 



27.9.18 



27.3 





28.6 



It will be seen that in this instance the lower end did have a 

 slight excess of moisture. The question has been worked on in 

 other ways, but no evidence is in favour of vertical or oblique 

 stacking. The reason why timber so stacked does dry more quickly 

 than timber in the rack is because the former is exposed freely to 

 the air, while in the rack the timber is stacked in a mass where 

 there is no circulation of air. It has already been mentioned that 

 timber in long lengths loses moisture mainly through the sides, 

 and not so much from the ends; but it was not known what part 

 •each surface took in drying. To ascertain this cubes were used 

 from 1 in. up to 4 in. They were Imade in sets of 5, each set 

 being cut from the same piece of timber. In all cases timber was 

 selected which had the rings parallel to one side. In each set, one 

 cube had all faces left clean, one had all six faces paraffined, and 



