goo 



BULLETIN OF THE BUREAU OF FISHERIES. 



desirable. Accordingly a number oi samples were boiled and the constituents 

 of the gas obtained in this way determined quantitatively by absorption. The 

 following table gives the results for the water just as it is delivered from the 

 well and before it has undergone any appreciable exposure to the air : 



Table I. — Carbon Dioxide, Nitrogen, and Oxygen in Cubic Centimeters per Liter of the 

 Untreated Water from the Electric Pump. 



[In all tables the gases are reduced to o° C. and 760 mm. (of mercury) pressure, and corrected for tension of aqueous 

 vapor. These are the standard conditions for stating gas measurements.] 



No. 



April 28, 1907 



I hour later 



April 29, 1907, II a. m _ 

 April 29, 1907, 3 p. m._ 

 April 30, 1907, 10 a. m. 

 April 30, 1907, 3 p. m.. 



o. 



0.71 

 0.28 



o 45 

 o. 20 



o. 13 

 0.06 



The carbon dioxide obtained by boiling water shows the amount dissolved 

 in the water as gas and part of that dissolved as bicarbonate salts, since the 

 latter decompose on boiling, liberating carbon dioxide as gas. This is not a 

 satisfactory method of determining carbon dioxide in water, and the figures are 

 included here only because it is necessary to obtain them in order to determine 

 the oxygen and nitrogen. They are not of especial significance. Probably, 

 however, a large part of this carbon dioxide is dissolved as the gas. 



The first determination is much higher in each gas than any of the others. 

 There is no satisfactory explanation for this. No. 5 and no. 6 were made after 

 the pump had been working continuously for 24 and 29 hours, respectively, and 

 are to be compared with no. 3 and no. 4, which were made at the beginning of this 

 continuous run. It appears from this that the water does not improve par- 

 ticularly with continued pumping. 



Water at 15.5° C. can take up from the atmosphere about 13.7 c. c. of 

 nitrogen and therefore this well water has an excess of about 5 to 10 c. c. of 

 nitrogen, or the normal and proper content has been increased 39 to 79 per cent. 

 This is the largest nitrogen superaeration that has been determined in Fisheries 

 station water, although at Woods Hole an excess of 5 or 6 c. c. in the sea water 

 was experimentally induced. It is known that such an excess is fatal within a 

 day or two at most, to many fishes, and that an excess of 2 or 3 c. c. is sufficient 

 to make considerable trouble. In this well water, however, the effect of the 

 excess of nitrogen upon fishes can not be observed since the deficiency of oxygen 



