( 468 ) 



derably so as to run as far as the concentration 3% before meeting 

 the melting line of the (i-substance. This is connected with the 

 flat course of the meltingline near tlie melting point of the raceraic 

 compound, which points to a great measure of dissociation in the 

 two active components in the liquid state. 



In fig. II it is the melting line of the racemic compound that, 

 owing to the lower melting point, has the smallest extension (final 

 point near 867o) but this too has a very flat form near the melting 

 point. 



Physics. — "0» the deduction of the characteristic equation." By 

 Prof. J. D. VAN DER Waals — discussion with Prof. 



BOLTZMANN. 



In the proceedings of the former meeting Prof. Boltzmann has 

 inserted a communication, accompanied by a letter. In this letter 

 Prof. BoLTZMANN has expressed the wish that bis communication 

 would give rise to a discussion. As the result for Prof. Boltzmann's 



values of the coefficients of — , — etc., which appear in the cha- 



racteristic equation, differs from that which I have obtained, I con- 

 sider the invitation to discussion as also addressed to me. And 

 though as a rule I prefer to leave the discussion between different 

 results, obtained in two different ways, to the gradual development 

 and extension of our views, which is brought about in course of 

 time, I will not abstain from complying with his request, in the 

 hope that this discussion may be „useful to science." 



I am perfectly aware of the difiiculties attending this discussion. 

 Prof, Boltzmann's „Vorlesungeu" form a logical coherent whole, 

 and the different results agree so well, that we may be sure that 

 they contain a perfectly correct solution of the problem, as Prof. 

 BOLTZMAKN conceives it. On the other hand I am convinced, chat 

 also my solution, leaving same unsolved questions and some minor 

 points out of account, gives a true explanation of the problem, as 

 I see it. So I pass by the question whether in equation (11) p. 403 



\1 h ^ b^ 



the factor of 2 Gb is to be put as 1 — \- ft — or whether ft 



32 V v^ 



2357 



must possiblv be diminished by , as this is of minor interest. 



^ ^ ■' 13440 ' 



As our results differ so much, we cannot but have considered 



two different problems, and to get some certainty on this point, I 



