-ELLOGQ # (continued) density of the radioactivity in the air was, I think, ie tionable to us at first; we were reassured, however, finding that MRL had already built equipment which t counters and which cost would be in the order of £200 | instrument, exclusive, of course, ef the balloons, It turns out now, that Fete Hyckoff tells us that the Air|Force is algo in the preliminary stage of developing a s equipment; using, however, inatead of countera, the ment of conductivity. 4 few flights have been made w show that the instrusent is practical and, presumably IT wa quoting you right-—-it could be done between $100 af 4 £200 per instrument, or something in that region, if or wanted to produce a lot of these. The radiosonde network already provides a Large nusber telenetering stations. It alse provides crews for balloons. This is an attractive ides, practically, beck it means one does not have to set up the balloon-leuich& network--it's already there; one would aerely tle on ox The question of how long we can track the cloud using conductivity measurements com up yesterday, and none of us was quick enough to make the calculations in our headas however, I figured from what was said yesterday, that ently the rate of creation of ions by ecoals rays in the»| region “ser cy a tee S98