80 



Reuben T, Patton 



values of the calculated losses and those actually obtained by weigh- 

 ing are given in the following table: — 







Table IV 



• 





Time in 



Calculated Loss 



Actual 



Difference. 



Oays. 



i=6.75t. 





Loss, 





5 



16.46 



gms. 



16.35 gms. 



+ .11 gms. 



8 



21.35 





21.45 



—.10 



16 



31.35 





31.40 



—.05 



23 



38.34 





38.65 



—.31 



37 



49.87 





50.10 



—.23 



48 



57.62 





57.80 



18 



69 



70.52 





69.20 



+ 1.32 



From an examination of Fig. 7 it will be seen that drying com- 

 mences and continues for a while as if the supply of moisture was in- 

 exhaustible. However, in a given thickness the amount of moisture 

 is limited, and therefore the curve of loss leaves the initial curve, and 

 finally becomes a straight line. Where the one curve leaves the other 

 it is difficult to say. In the small thicknesses the change is some- 

 what abrupt, but as thicknesses increase the change becomes less and 

 less abrupt. This is because the secondary curve does not leave the 

 main curve at the same moisture content in each case. In the small 























CHESN^ 



JT 

























JS' 







(to 

















^ 





^ 



" 









t 















/ 



^ 







60 





















^ 



^ 













I'f. 



















ili 









40 

























^ 















. i' 

























i 









eo 

















i' 













f 



















Fig 7 







« 



J 4- 



J 



a 



K 



)0 



O M 



O »« 



to It 



30 «c 



o U 



M> 



Time in days. 



Series of Curvks Illustrating Loss ok Moisture for Various Thicknessks 



OF Timber. 



sizes the moisture has only a small distance to diffuse, in order to 

 reach the surface, and hence the curve of loss for thin sections coin- 

 cides with the envelope for a relatively longer period than do the 

 curves of loss for thicker sizes. The rate of loss is greater on the 

 main curve than on the secondary, and hence these sizes dry rapidly. 

 This was observed by Tiemann(2), for he says: " For one half inch or 



