REVIEWS 711 



substantiated by the note on page 30, at the close of Table 8, to the 

 effect that the theoretical number of available heat units in a cord of 

 air-dry longleaf pine is 22,000,000 B. T. U. In case this air-dry long- 

 leaf pine contains 20 per cent resin, it will have a value of approxi- 

 mately 26,400,000 B. T. U, 



After studying these figures one comes to the conclusion that if 

 further attention is to be given to the use of wood for fuel, more defi- 

 nite figures on the actual heating values of different kinds of wood 

 must be secured. The only practical method of determining the true 

 heat value of any fuel is to burn it in a bomb calorimeter or some 

 similar device for directly measuring its heat value. As yet, very few, 

 if any, such figures seem to be available. It is quite apparent that the 

 compiler did not have access to any. 



Some interesting data for the purpose of assisting to prepare cost 

 figures on the preparation and transportation of cordwood are given. 

 On page 20 a plea is made for the selling of fuelwood by weight instead 

 of by volume. This suggestion deserves careful consideration, for the 

 advantages to both the producer and consumer are many. Practically 

 all the available information on the use of wood fuel is here presented, 

 as well as a summary of the various methods employed for promoting 

 the use of wood for fuel. On the whole, the Forest Service is to be 

 commended for preparing a bulletin wherein may be preserved the 

 bulk of information regarding wood fuel, which appeared as a result 

 of our participation in the world war and the accompanying fuel 

 shortage. 



Recent figures compiled by the Federal Bureau of Crop Estimates 

 make one wonder to what extent wood really did help out in conserv- 

 ing coal. In spite of the special State bulletins and the wood-cutting 

 bees, descriptions of which filled the papers ; in spite of the experience 

 of many patriotic individuals who tried to save coal by burning wood, 

 there is recorded no remarkable increase in either the production or 

 consumption of wood during 1918. The figures recently given pub- 

 licity show that a total of 102,903,000 cords of fuelwood were pro- 

 duced in 1918, of which 77,092,000 cords were used on the farms. 

 The writer has been unable to get definite figures showing the produc- 

 tion of cordwood for 1917, but the amount consumed on farms is 

 given as 82,777,000. It was estimated before the war that our annual 

 production of cordwood was about 100,000,000 cords. This is in line 

 with the figures given for 1918, which in turn show a considerable re- 

 duction in the use of cordwood on farms for 1918. The average cord 

 value at the farm or near-by town increased from $3.42 in 191 7 to 



