910 
are not strictly valid, c. in a change with the temperature of the 
quantity @ which occurs in that theory, in other words of the elastic 
properties of the material *). 
Concerning } it may be remarked that for a substance which should 
crystallize in the simplest cubical space-lattice Trurring has derived 
an expression for the specific heat from the theory of Born and 
v. K&rmsn which in consequence of the more rigorous consideration 
of the molecular structure followed in this theory might give a nearer 
approximation to the actual conditions. It is true that for a thorough 
discussion in connection witb Txrrrine’s deductions the data about 
the elastic constants in the temperature region considered are as yet 
wanting. Without these we can, however, establish the following facts. 
In table VI are given besides the deviations (W-Rp) between the 
TABLE VI. 
: Cy gs 6 à 615) Ee me | 
ee ME Ë iz os —_ ek 
facto | 1.56 4 0.085 | 
15.315 1.815 + gs 
16.275 1.99 Bie ge | 
17.24 2.17 EPD + 0.26 7 
18.255 2.41 dort + 28 | 
19.27 2.53 0 TG | 
20.305 2.66 ER aen 
22.31 2.97 EN, Ed 
27.51 | 3.59 eae: Lied 
28.50 3.65 ae nee 6 — 0.20 
36.495 4.45 aD: See one 
se ihe whee 0 0 4 aid 
58.00 5.32 Ee ee oi ENG 
observed values of C, and those calculated according to DrBuu 
with @ = 88, also the deviations W-Rz7,,, between the observations 
and the values calculated from a series given by THrRRING : 
1) In determining this influence it should be borne in mind that, as is specially 
pointed out by Everen, Verh. d. D. physik. Ges. 15 (1913), p. 571, the elastic 
properties must have been measured on homogeneous crystalline material. 
= 
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