DRINKING WATER FROM SEA WATER — CONSOLAZIO, ET AL. 155 



breath was condensed in a wet felt-jacketed metal container. The 

 calculated efficiency peak for such a method is but 15 milliliters of 

 water per hour and even with a tight-fitting mask and a highly effi- 

 cient condenser this degree of efficiency was never reached in labora- 

 tory and field tests. Under experimental conditions a maximum of 

 5 milliliters per hour was attained and no subject was found who could 

 tolerate the device for 8 hours. Another limiting factor was that the 

 device required quantity production from an already overtaxed metal- 

 working industry. 



4. Delano solar still (2), (4). — The source of heat for this still is 

 solar radiation. The sunlight passes through a transparent plastic 

 window and is absorbed by black toweling which backs up the plastic 

 sheet. The toweling is kept wet with sea water, and the evaporating 

 moisture condenses on the plastic window and drains into a reservoir 

 at the bottom of the still. Under ideal conditions the apparatus was 

 capable of producing 300 milliliters of water a day, but it was much 

 too fragile for life-raft use. In fact the models tested in the labor- 

 atory required continual repair. Another disadvantage was that the 

 apparatus had to be oriented to the sun. On a cloudy day, there- 

 fore, the efficiency of the still fell off markedly. In view of these 

 disadvantages and its bulk, the canned water, then available, was to 

 be preferred. 



Since all the above devices were unsatisfactory, chemical methods 

 of treating sea water presented possibilities. 



5. Goetz method (1). — This method was one of the earlier chemical 

 methods and one that received considerable publicity for the reason 

 that the ratio of water produced to the volume of chemical employed 

 was of the order of 14 to 1. It required little manipulation — sea water 

 was scooped into a plastic bag into which was dispersed a small pack- 

 age of silver and barium oxides. The chlorides of sea water were 

 precipitated as silver chloride, the sulfates as barium sulfate, resulting 

 in a solution of approximately 0.3 N alkali which caused the magnesium 

 in sea water to precipitate as magnesium hydroxide. The precipitate 

 was allowed to settle and was then clamped off in the bottom of the 

 bag leaving a cloudy supernatant fluid. Into this was stirred a cake 

 of citric acid which neutralized the sodium hydroxide to sodium ci- 

 trate. Thus the end result was the conversion of the approximately 

 3 percent sodium chloride of sea water into approximately 3.3 percent 

 sodium citrate. 



The limiting factor in the use of this water was that the sodium 

 citrate was converted by the human organism into sodium bicarbonate, 

 with a resultant severe alkalosis. The kidneys, in order to rid the body 

 of this excess alkali excreted an excess of water, which led to more 

 severe dehydration than if the water had not been drunk. Though 



