( 388 ) 
again remains the same: the constant C is diminished by a certain 
definite amount. I hope afterwards to be able to treat this question 
more fully. 
I believe to have proved by the foregoing that the law concerning 
the relation of stimulus and effect prevails also for other organs than 
the muscle, more especially for the nerve-fibre and for the eye. 
This law is therefore to all probability a general law, prevailing 
for every excitable organism, 
Geology. — ‘On the Supply of Sodium and Chlorine by the Rivers 
to the Sea.” By Prof. Kue. Dusors. (Communicated by Prof. 
H. W. Baknuis RoozeBooM). 
Fifteen years ago Sir JouN Murray has, at the end of a now 
well known paper on the total annual discharge of rivers, given a 
small table showing the amount of dissolved matter in average river 
water !). He states to have taken the analyses of 19 rivers “as 
representing on an average the composition of river water” and 
promises a subsequent paper, in which the amount of matter in 
solution would be discussed in some detail *). This, as far as I know, 
has not yet appeared; but it is possible, by comparing the figures, 
to find those 19 rivers which most probably have been chosen by 
Murray, from the analyses known till 1886, for his calculations of 
averages. Those averages then appear to have been arrived at by 
joing the quantities such as they are stated in the analyses. 
The mentioned table of 14 salts, for the first time giving averages 
of the existing data concerning the amount of solid matter conveyed 
annually in solution in the river water from the land to the sea, 
has ever since its appearance been dear to geologists, as it seemed 
to enable them in some degree to give a more concrete form to the 
notions they had of the process of denudation lying at the base of 
geological knowledge. 
BiscHor and Rorm?) had already compiled a great number of 
analyses of river water in their text books of chemical geology 
1) Joun Merray, On the total annual Rainfall on the Land of the Globe, and the 
Relation of Rainfall to the annual Discharge of Rivers. Scottish Geographical Magazine. 
Vol. III. February 1887, p. 71 en 76. 
*) Sir Joux Murray does not tell us the names of those 19 rivers, nor that many 
of them are principal rivers of the world.” The nineteen rivers in his Table VI 
are not those of which the analyses have been taken for the estimate of the average 
composition of river water. 
3) G. Brscnor, Lehrbuch der chemischen und physikalischen Geologie. Zweite Aufl., 
Bd. 1, p. 269—279. Bonn 1863. —J. Roru, Allgemeine und chemische Geologie, Bd. I, 
p- 454—462, Berlin 1879. 
