[5] RETTING WATER INJURIOUS TO FISH. odd 
usual offensive decaying process took place, developing substances 
whose composition is well known. My attention was, therefore, directed. 
to the gaseous matter developed during the process of decomposition, 
and as these gases withdraw the oxygen from the water they are highly 
injurious to the life of fish. 
IIl.—TO DETERMINE THE GASES. 
Frequent experiments as to the gases contained in spring and running 
water (see this Journal, vol. 202, p. 258) showed the proportion found by 
Regnault, Bunsen, and others, viz, oxygen and nitrogen as 1:2, whilst 
the proportion of oxygen to nitrogen in the air is 1:4; 7. ¢., the solution 
of these two gases in water corresponds to these fully established pro- 
portions. 
In 1,000 cubic centimeters of water taken from the river Saale during 
spring (see this Journal, vol. 206, p. 206) I found 30 to 31 cubic centi- 
meters gas; these contained, at a temperature of 3° C., 6.2 per cent. ear- 
bonic acid; this percentage rose, when the temperature of the room 
grew warmer, to 16.5, without any noticeable change in the total quan- 
tity of the gas. One experiment showed that the water of the river 
Saale, at a temperature of 3° C., contained one part oxygen to 4.78 parts 
nitrogen, whilst a second experiment showed the proportion of these 
two gases to be 1:1.91. After the water had become somewhat warmer 
in the room the proportion was 1 part oxygen to 2.2 parts nitrogen; 
therefore the same as the one given above. 
Water in which hemp had been retted, and which had attained a con- 
siderable degree of putridity, was found to contain in 554.3 cubie centi- 
meters of water, 35.5 cubic centimeters gases, which might be expelled 
by boiling ; this would make about 64 cubic centimeters gases in 1,000 
cubic centimeters water. Calculating the percentage I obtained the 
following result: 
LSE SUECETT Ve SIS a nee mee rN De rer ego y Sn n> ROR eat 
Lele De Og aan ae eae ee reer rer er ot 29,9 7.0 
“DTP DDT YE" CCT Pe een Oy rnin Sire yee © 65.9 
100. 0 
While river water mixed correspondingly shows a proportion of 1: 2, 
this mixture shows a proportion of 1 : 7. 
Carbureted-hydrogen gas, hydrogen or carbonic-acid gas could not 
be discovered, which may possibly be owing to the degree of putridity 
and to the difficulty of solving these gases in water. But these pro- 
portions must also be considered in connection with carbonic acid, which 
is just as hurtful to fish as nitrogen. 
The percentage of gases in two different specimens of water trom the 
river Saale (the temperature of the room being 20° C.), was that given 
