RESULTS. 15 



TABLE 1. Specific heat of oven-dry wood averages by species. 



1 For the rejection of 16 determinations see appendix. 



2 The determination of the correction is discussed in the appendix. 



The average of the calculated values for the specific heat of wood 

 obtained by giving equal weight to each of the 20 species studied 

 is 0.3244; that obtained by giving equal weight to each of the 100 

 runs shown in Table 1 is 0.3249. The close agreement between these 

 averages, in spite of the fact that one-half of the runs was made 

 upon Douglas fir and maple, shows strikingly how little influence 

 species has upon the specific heat of wood. The average referred 

 to hereafter, unless otherwise specified, will be that giving equal 

 height to each of the 100 runs 0.325 calculated, or 0.327 corrected. 



The table shows the specific heat of longleaf pine to be about 3 

 per cent greater than the average, and that of chestnut to be the 

 same amount less. But the values for these species are the mean 

 of only a few results, and are therefore much less reliable than the 

 average with which they are compared. A consideration of the 

 probable error of the observations indicates that this difference 

 must be at least 4 per cent to acquire significance. The differences 

 shown in the table may be real, but are too small to be significant, 

 and furnish no basis for drawing a distinction between the specific 

 heat of different species or of conifers and broadleaf trees. There- 

 fore, the mean specific heat of oven-dry wood may' be considered 

 0.327, and this figure remains nearly constant for all wood. 



EFFECT OF LOCALITY. 



The variation in specific heat within a species due to the locality 

 in which it is grown was so small and inconsistent as to furnish no 

 basis for concluding that locality influences the specific heat of 



