326 MORRIS M. WELLS. 



same, for after the water had passed through the coolers in the 

 apparatus, its temperature was the same as that of the cold 

 water running through the coolers. In these experiments the 

 temperature differed slightly on different days but was constant 

 between 3 and 5 degrees centigrade. 



By analyses, which are given in Shelford and Alice's paper, 

 it has been shown that there is little chemical difference between 

 the hot and cold tap water of the laboratory. At the time the 

 analyses were made, however, it was found that the tap water 

 after it had passed through the gas control apparatus, showed a 

 slight increase in magnesium content. By later analyses, I have 

 found that this increase was due to the accumulation of mag- 

 nesium containing scale, in the boilers. To obviate this differ- 

 ence, I have kept the boilers free from any considerable accumu- 

 lation of scale, and although no further analyses have been made 

 since the beginning of the experiments, I do not think it likely 

 that the effect of the apparatus upon the water has been any 

 greater than the normal daily fluctuations of the water itself, 

 excepting, of course, the differences that have been intentionally 

 produced. 



After passing through the gas-control apparatus, the water 

 was led into a 2-liter wide-mouthed bottle (see Fig. i). The 

 introducing tube led the water to the bottom of this bottle, while 

 the exit tube reached half way to the bottom. Thus all gas 

 bubbles were retained in this first bottle and not allowed to pass 

 into the experimental bottles. From bottle A, the water passed 

 into a larger (8-liter) bottle, B. This was the first experimental 

 bottle. From bottle B, the water was led into still another 

 bottle, C, which was the second experimental bottle. 



An experiment was conducted as follows. The gas-control 

 apparatus was started and allowed to run from two to four 

 hours, so that the gas concentrations might be regulated and 

 made constant. The time required for this varied with what was 

 to be done to the water. When consecutive tests, five to ten 

 minutes apart, showed the concentrations to be those wanted, 

 and constant, the hose connected with the outlet of the apparatus 

 was slipped over the inlet tube of bottle A , the outlet tube of A 

 connected with the inlet tube of B, etc. After the stream of 



