( 271 ) 



either not marked or very faintly marked in some places by longi- 

 tudinal striations. 



The base of the main stem of the s[)eeimen is 6 m.m, in diameter 

 and the primary branches are 4 — 5 m.m. in diameter. 



Some further particulars concerning the anatomy of the species 

 will be described with illustrations in a future publication. For the 

 present the diagnosis of the species given al)ove is sufticient. Before 

 concluding this preliminary note I ha\'c, with very great regret, to 

 record that on Sept. 22"^ a tire broke out in my laboratory and 

 some portions of the specimeu were seriously burned and scor- 

 ched. Fortunately there is still a considerable fragment that appears 

 to be uninjured. 



Physics. — ''rroperties of the critical line (plaitiiouit line) on the side 

 of the components y By Prof. VxVN der Waals. 



By Centnerszwer and Smits' observations, l)y a remark of van 

 't Hoef and by van Laar's calculations ^) a discussion has been car- 

 ried on on the rise of the critical temperature of a substance in 

 consequence of an admixture. In this it has been perfectly over- 

 looked that already more than ten years ago the principal properties 

 of the critical Ihie, and also the properties at the beginning and at 

 the end of this line were discussed and determined by me ^). 



For normal substances, I found by a thermodynamic method, which 

 is a perfectly sure way, for the quantity mentioned the formula (9) 

 (I.e. p. 89) 



dTd? ~ UrT \J7hi 



I shall explain further on why I make some reservation for abnormal 

 substances. 



And with the aid of the equation of state 1 derived from (9) for- 

 mula (11) 



1) These Proc. p. 144. 



2) Verslag Kon. Akad. v. Wet. 25 Mei 1895, p. 20 and 29 Juni 1895, p. 82. 



