REACTIONS OF FISHES TO ATMOSPHERIC GASES 



217 



is 90 feet deep. (2) The hot water is from the same general 

 supph' but passes through a heater into which Uve steam is 

 introduced. It comes from the tap in the laboratory, where the 

 apparatus is installed, at a temperature of from 40 to 60°C. and 

 is highly supersaturated with gases; this water was used for 

 boiling. 



A large number of metals were used in the apparatus, princi- 

 pally because the materials were at hand, but it was also thought 

 that the use of such metals followed by chemical analysis would 

 show what effect they have upon the water. It may be noted 

 that the water supply of most laboratories is pumped with pumps 

 which are lined with brass and copper and is then carried for 

 long distances through iron pipe, galvanized and ungalvanized, 

 so that there is little use of making the last 60 feet of pipe of some 

 special metal except where heat is applied. 



TABLE 4 



Shoiving the effect of the apparatus upon water. Analysis: solids in parts per million 

 by Mariner and Hoskins and gases in cc. per liter 



' Increases shown are due to resolution of precipitated salts as shown by repeti- 

 tion of analysis of the water and analysis of scale from the boilers by M. M. 

 Wells. The magnesium in the boiled water probably varied from time to time 

 and the statement that it was reduced (Shelf ord and AUee '12) is probably incor- 

 rect for most of the experiments. 



THE JOURNAL OF EXPERIMENTAL ZOOLOGT, VOL. 14, NO. 2 



