( 432 ) 



The differences with the earlier values remain, notwithstanding 

 wo liave used entirely different data, far within the limits of the 

 iiccuracv uicuiioned in § 3 (loc. cit.). The coefficients of the formula 

 given there become: 



^< = — 0.007117 



h = ^ 0.005962 



c = — 0.000185 



J= + 0.001330 



With this formula the temperatures of the second column have 



been deterniined. The differences between the data of the last column 



but one and the formula are given in the last column. 



For — 273° the new formula gives the same value as the one 

 before of Comm. N". f>7^ i.e. Z.^=-f-0M4, for 0^ 0. and +100°C. 

 it gives Lt = 0°. For the temperatures between 0" C. and UHV C. 

 the formula yields much larger negative values than those whicii 

 Berthelot iias derived with his e(|uation of state (loc. cit. IX). For 

 20°, 50° and 80° arc found: according to Hekthelot : 



A< = — 0°.0004G — 0°. 00053 and — 0°.00033 



according to our formula : 



At = — (f.()()\2 — 0°.0020 and - 0". 0014 



According to the general equation of state of hydrogen derived 

 previously (comp. § 1 Comm. N". 97'') these values would be 

 respectively : 



— 0°.0026 . — 0^0047 , - 0°.0036. 



Geology. — "On the terms Schalie, Lei and Schist.'' By Mr. .1. 

 Schmutzer. (Communicated by Prof. C. E. A. Wichmann). 



East-Indiau mining engineers, by whom almost exclusively the existing 

 descriptions of rocks in Dutch have been written, under the influence 

 of the German literature relating to this subject, have used the terms 

 schiefer and lei side by side, on the whole with hardly any difference. 

 The cause of this is the want of a fixed geological terminology in 

 our language; a want which of late has also been felt by the "Ned, 

 Mijnbouwkundige Vereeniging", as appears from its attempt to create 

 such a terminology under the supervision of Prof. G. A. F. Molex- 

 GRAAFi'. The purport of this communication is to aid in solving the 

 problem, lahat terms are best titted to denote in Dutch those rocks 

 which in German bear the name of Schiefer in the amplest sense 

 of the word. 



