332 SUMMARY AND CONCLUSIONS 



liquids, it is found that the spectrum of the dayUght at 

 800 feet in the sea has a maximum brightness at about 

 500 mfi; this agrees well enough with the observation." 



In the course of Dive 20 (2200 feet, Sept. 22, 1932) 

 although my eyes were perfectly dark-adapted, I could de- 

 tect not the faintest glimmer of light, with my naked eye, 

 at 1700 feet. On Dive 30 (2510 feet, Aug. 11, 1934) and 

 Dive 32 (3028 feet, Aug. 15, 1934) the last light on the 

 white packing of the quartz windows was observed at 1900 

 feet, both going down and coming up. The additional 200 

 feet of visible daylight penetration was undoubtedly the 

 result of the unusual clarity of the sunny day, plus the 

 very calm surface. From 2000 feet down, as far as the 

 unaided human eye was concerned, conditions of absolute 

 darkness existed. 



(b) Temperature 



Temperature records are as follows: 



800 feet lowest inside 75° Fahr. outside 65° Fahr. 

 2200 feet lowest inside 70° Fahr. outside 53° Fahr. 

 2510 feet lowest inside 70° Fahr. outside 51° Fahr. 

 3028 feet lowest inside 68° Fahr. outside 45° Fahr. 



(c) Pressure 



Inside the bathysphere we had, of course, no means of 

 recording the increasing pressure. At the end of the several 

 two to three hour dives, when the wing-bolt was removed 



