( 342 ) 
The following table of the E.M.F.’s of Crark-cells containing 
solid ZnSO,.7H,O or Zn8O0,.6H,O is given by JArGER Ì) in 
his memoir. In the last column I have added the E. M. F.’s of our 
transition element. 
TABLE ote 
E.M.F. E.M.F. | E.M.F. 
Temperature. in millivolts. in millivolts. | Transition cell 
| ZnSO,.7H,O | ZnSO,.6 H,O | in millivolts. 
ge 1449 1434 15 
10° 1439 1427 12 
20° 1427 1418 | 9 
30° 1414 1409 | 5 
390 | 1400 | 1400 | 0 
From these figures the temperature coefficient is 
of : 0,55 millivolt 
=== SOO Oa J MUVO 
(a) 9 RE AVENE 
whiist the thermodynamic calculation gave — 0,51 millivolt ; the 
agreement is, thus, very satisfactory. 
In a subsequent paper I shall show that the E. M.E. of our 
transition cell at other temperatures may be calculated by thermo- 
dynamics. 
Amsterdam, University Chemical Laboratory. 
December 1899. 
Chemistry. — “On the nitration of dimethylaniline dissolved in 
concentrated sulphuric acid”. By Dr. P. vAN ROMBURGH. 
(Communicated by Prof. A. P. N. FRANCHIMONT.) 
Some years ago”) I had the honour of communicating to the 
Academy the results of an investigation of two new dinitro-deriva- 
tives of dimethylaniline obtained by dissolving this base (1 mol.) in 
1) WrIEDEMANN's Annalen 63 (1897), p. 356. 
2) Zittingsverslag 23 Februari 1895. 
