many thousands of dollars because of a minor design change in the 

 battery which was unknown to us; the catalog number or anything of 

 that sort had not been changed. What had been a previously useful 

 battery became useless with a small temperature drop. 



The introduction of unannounced changes is one of our prob- 

 lems. I referred to the problems of the electrolytic capacitor 

 earlier. One may find a type of battery that is acceptable for high 

 pressure operations. You attempt to replace it by ordering a new 

 lot. For some reason, the new batch simply will not perform. 

 Small changes have been made in manufacturing techniques which 

 ruin it for high pressure use, but which probably make it better 

 for other people. 



Storage batteries are probably one of the brightest lights 

 that we have as far as useful power supplies are concerned. The 

 ordinary, homely, lead-acid automobile battery works very well. 

 All you have to do is to protect the terminals from salt water, fill 

 the cells clear up with acid of the proper gravity, and provide a 

 small expansion chamber. They will operate very happily at any 

 depth. The low gravity, low self-discharge types may actually 

 give you the order of 80 percent of their capacity after being on the 

 bottom for times as long as one year. Silver cells which are a 

 more sophisticated storage battery have been tested up to pressures 

 of 80, 000 p. s. i. These, too, show a very satisfactory performance. 



There are air-breathing types of power supplies, sonne 

 undergoing very rapid development at present, particularly those 

 classified as the propane -fueled thermoelectric cells. These, at 

 present, are essentially low wattage devices; they apparently 

 possess high reliability. However, the reliability in the marine 

 environment has not yet been, as far as I know, thoroughly estab- 

 lished and needs to have a great deal more work done. For example, 

 it would appear that something like 200 grams of salt would have to 

 pass through a modestly small burner in the course of a year's 

 operation in a buoy at sea. What is to be the fate of this salt, what 

 reaction it will have on the burner, its materials, and so forth, I 

 do not know. Mr. Allyn C. Vine of Woods Hole Oceanographic 

 Institution is very partial to the concept of another air-breathing 

 device, namely, the diesel electric generating system. This has 

 high reliability, and, if one needs substantial amounts of power, 

 they should not be overlooked. 



Of course for certain specialized applications, for example, 

 52 



