384 



FORESTRY AND IRRIGATION 



August 



which they are saturated. The water 

 is caught in a trough underneath the 

 condensing coils, and passes out of the 

 kiln through pipes. 



When the boards enter the cool or 

 wet end of the kiln, they are subjected 

 to several hours of sweating at a tem- 

 perature of 140 degrees Fahrenheit, 

 the cold-water supply being discon- 

 nected from the first pair of condens- 

 ing coils, and the canvas curtain drop- 

 ped to form the sweating chamber. 

 When the wood has been thoroughly 

 sweated, the curtain is raised and the 

 condensing coils are put in operation. 

 Then evaporation and condensation 

 take place throughout the whole kiln. 

 The trucks are gradually moved along 

 toward the hot or dry end of the kiln, 

 where an average temperature of 180 

 degrees is maintained. 



Considerable importance attaches to 

 the piling of the heading boards upon 

 the trucks in such a manner as to 

 avoid molding, warping, and checking. 

 To obviate the first difficulty, a space 

 of not less than six or eight inches 

 must be left between the ricks. Un- 

 even laooing of boards either at ends 

 or sides is sure to cause warping; and 

 cross-sticks must be used at the ends 

 of the boards to prevent warping and 

 checking. The boards of the upper 

 layer, being subjected to greater heat, 

 and ordinarily without weight to hold 

 them in shape, should have planks or 

 some device superimposed to put the 

 upper course under conditions similar 

 to those lower in the pile ; otherwise 

 the topmost boards will warp. 



Although it is not the general practice 

 the removal of the bark on the edges 

 of the boards by means of a rosser or 

 an old jointing knife would hasten the 

 drying, and tend to lessen mold, in ad- 

 dition to economizing space and sav- 

 ing the heat energv of the kiln. 



The results of the treatment prove 

 its success. As before stated, the 

 boards were put into the kiln just as 

 they came green from the saw. They 

 were in the kiln from six to seven 

 days, and when taken out they were 



found to be dry, free from mold, and 

 practically without checks. Under 

 other methods of drying at the same 

 plant, 31 per cent of red gum heading 

 boards had been warped ; but in these 

 experiments the warpage was de- 

 creased to 14 per cent, and with one 

 truck load only 8 per cent of the 

 boards was warped. 



Mine 

 Timbers 



The following statistics 

 on the timber used in the 

 anthracite coal mines of 

 Pennsylvania are compiled from the 

 reports of the mine operators to the 

 Forest Service and the Geological Sur- 

 vey. 



Reports were reiceived from 216 

 collieries, producing approximately 83 

 per cent of the total anthracite tonnage 

 of the United States. Figures for the 

 remaining 17 per cent were computed, 

 using as a basis the reports actually 

 received, assuming that conditions and 

 requirements were uniform through- 

 out the state. 



The results of the tabulations show 

 that 121,565,000 feet board measure of 

 sawed timber (equivalent to 10,130,000 

 cubic feet) and 52,440,000 cubic feet 

 of round timber were used during 

 1905. 



The total value of the sawed timber 

 was $1,842,000, or $15 per thousand 

 feet board measure. The total value 

 of the round timber was nearly double 

 that of the sawed timber, being $3,- 

 468,000, or $6.60 per 100 solid cubic 

 feet the approximate equivalent of 

 the average standard cord of 128 cubic 

 feet. The total value of the round and 

 sawed timber combined was $5,310,- 

 000, or about 8>y? cents per long ton of 

 coal mined, using as a basis for the cal- 

 culation the production in 1905 111 

 round numbers 61,000,000 long tons. 



So far as reported, the kinds of 

 wood have been tabulated separately, 

 but in many cases the operators were 

 unable to furnish information in re- 

 gard to the quantity of each species 

 used, and it has therefore been neces- 



