RESULTS. 



17 



The two following rules may be laid down for the practical use of 

 these results : 



1 . When the particular species, the specific heat of which is desired, 

 is one of the eighteen named in Table 1, use the corrected value given 

 in the last column of the table. 



2. When the particular species is not given in Table 1, or is un- 

 known, or when the wood of more than one species is lumped together 

 in unknown proportions, use the value 0.327. 



VARIATION IN SPECIFIC HEAT WITH TEMPERATURE. 



In determining the variation in specific heat with temperature, the 

 mean specific heat between 106 C. and C. was taken as one point. 

 Runs were made from approximately 65 and 25 to determine the 

 mean specific heats between each of these temperatures and C. A 

 larger number of intervals will be necessary before the shape of a 

 curve showing the variation in specific heat with temperature is 

 known. The present results can be considered as only preliminary 

 because the peculiar precautions taken to keep the wood in an oven- 

 dry condition at these temperatures introduced errors which were 

 not entirely removed by correction. The results are given in Table 4. 



TABLE 4. Results of determinations with different initial temperatures. 



The highest values obtained for each temperature are the most 

 probable. Even these indicate an unusually large variation of 

 specific heat with temperature. 



By plotting the values for the two lower temperatures shown in 

 the table and that for 106 C. already obtained, it was found that 

 the specific heat of wood falls to the neighborhood of 0.266 at C. 

 Therefore, when represented by a straight-line formula, the value of 

 the true specific heat at temperature t is indicated by the following 

 equation : 



Specific heat = 0.266 + 0.00116* 



