232 THE BATHYSPHERE OF 1930 



into cannon-like projections in the front of the tank. The 

 joint is secured with a paper gasket and white lead, and a 

 light steel frame is bolted over each one in front. In all we 

 have had five quartz windows. The first was chipped in 

 an attempt to grind it into its seat. The second gave way 

 under an internal pressure test of one thousand two hun- 

 dred and fifty pounds to the square inch. It seems probable 

 that the frame in front was bent out, and that the result- 

 ing shearing strains broke the glass. The third was broken 

 when the frame bolts were tightened unevenly. The re- 

 maining two, however, have never leaked a drop, and have 

 withstood the pressure at twenty-four hundred feet, and 

 will, no doubt, hold much more. 



The electric cable was specially made by the Okonite 

 Company. It is one and one-tenth inches in diameter and 

 has a heavy rubber insulation. Inside are two conductors 

 for the lights and two for the telephone. The cable passes 

 through a stuflSng-box in the top of the tank and is 

 squeezed up by two glands, one on the outside of, and the 

 other within, the sphere. It, too, proved entirely water- 

 proof under all pressures we encountered. 



The two big conductors passed to a two hundred and 

 fifty watt spot-light (loaned by E. "W. Beggs of the West- 

 inghouse Company) in the right forward projection. We 

 were obliged to seal the left projection with a steel plug, 

 since only two quartz windows were left. At depths of over 

 seven hundred feet the beam of light could be seen passing 

 through the water. When more illumination was desired, 



