Jack, that was a pretty good post, and I largely agree with you. I would, however, point out that although hygrothermographs satisfy the decision rule of Occam's Razor ("Exchew complexity," aka "K.I.S.S."), they are not absolutely "bulletproof." We have found that their Achilles' Heel is the clock-work drive mechanism . . .which has recently crashed, at one time or another, half of our instruments. Yes, of course, they are available battery-powered, and I have no experience with those. Subject to the reliability limitations of low-voltage fractional-voltage motors (and batteries and those who monitor them) this might answer the problem. Henry Grunder Conservation/Preservation Coordinator The Library of Virginia