162 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 194 5 



of the chemical was, therefore, recommended to the Permutit Co. It 

 was pointed out, however, that too much pressure made the briquets 

 indispersible and, therefore, useless. Fortunately, an earlier observa- 

 tion at the Naval Medical Research Institute permitted much greater 

 compression than had formerly been possible. If an inert chemical 

 which swells to 6' to 12 times its original volume when exposed to water 

 is added to the briquets, it acts as a disruptive agent. This develop- 

 ment was incorporated into the new Permutit briquets, and proved 

 very successful. The result has been that an exceptionally small briquet 

 can now be manufactured which, within a minute after being added to 

 sea water, crumbles and falls apart into very small sandlike particles. 

 Table 2 presents the water analysis of the major constituents of the 

 drinking water produced by this process. 



Table 2. 



-Salt content of tvater produced by the Permutit method as modified 

 by the Naval Medical Research Institute 



All values are maximal and are expressed as ME/liter. 



Briquets with the latest modifications are now in mass production 

 and are being packaged in a can exactly the same shape and volume as 

 the standard Navy water can. This design was chosen by the Naval 

 Bureau of Aeronautics in order to minimize changes in the parachute 

 back pad and parachute type raft. Calculation from the figures given 

 in table 1 shows that the new briquet yields the following ratios as 

 compared to packaged water: 



Weight ratio . 

 Volume ratio. 



Demineral- 



izing equip- 

 ment 



5.4 

 7.1 



Packaged 

 water 



0.7 

 0.5 



This can, filled with water, occupies a volume of approximately 

 700 milliliters and weighs approximately 512 grams, containing a 

 volume of water of 340 milliliters. The same can, containing demin- 

 eralizing equipment, has a total weight of approximately 800 grams 

 for a total volume of approximately 700 milliliters. The demineraliz- 

 ing equipment will have a potential supply of 3,000 milliliters of 

 water, a gain of approximately nine times the available water for 

 the same given space. The man-days of available water (500 milli- 



