911 
B, fOr) 5 Bf Ore Orn | 
eee 5 NS SY tan) | in EE Re Pea 
ies | Sl r) Be 7) oak ol 4°) 
in which 5,,5,... are the Bernouillian coefficients and Oy, is a 
constant. Apparently the agreement of the observations with DrBun’s 
formula is closer than that with this series of Tuirrine. 
It deserves further to be noticed, that this series can only be 
derived from the theory of Born and v. KArman by the introduction 
of imaginary values for the elastic constants (assuming that they are 
independent of the temperature). From the series which Turrrine 
derives from the theory a aaa above : 
h B IN 
Gie: — Re ere 
| 2 yo Ba tae a Ee ' ©) 
where /,, /,...-/, represent definite functions *) of the elastic constants 
Cry) Eys Coo introduced by Vorer, the following series may be derived 
as the one which at the higher temperatures approaches nearest to 
series (4)”): 
Orn Or, Bf OT%\' 
1— Sa 1 == = == 1825: — 5 ee " 
= a “5 mal “a ae a 
B, On $ | ; 
+ 163987 (on el Pd 
Under W—Rm, in table VI are given fe deviations between the 
observations and the values calculated from (6) with 47, = 68. It 
appears that Tuirrine’s formula (5) with the special assumptions 
concerning the elastic constants for which it passes into (6), in the 
region for which the coefficients have been developed by him, 
practically coincides with Desise’s formula. Whereas, when the 
elastic constants do not agree with those assumptions, THIRRING’s 
formula deviates from Dersisr’s formula in a direction opposite to 
the observations. 
Hence we come to the conclusion that a closer consideration of 
the molecular structure in the sense in which it is done in the 
theories of Born and v. Kirmin and of Tuirrine, at least on the 
assumption of the arrangement in the simplest cubic space-lattice, 
does not account for the deviations indicated above. 
It remains either to consider an arrangement in one of the other 
space-lattices of the regular system *), or to assume that one or both of the 
_D H. Turrrine, Physik. Z.S. 14 (1913), p.870 and 15 (1914), p. 181 note 1. 
2) This would require cj = 4 C44, G12 = O- 
5) A comparison with the deduction by Born, Ann. d. Phys. (4) 44 (1914), p. 607 
of Cy for the space-lattice as deduced. by Brace for diamond (also a regular 
crystal) leads, however, to quite analogous results as are given above for the simplest 
cubic space-lattice. 
