David Harvey <[log in to unmask]> writes: >I am interested, however, in how insititutions utilize their hygrothermograph >charts. We rely heavily on hyugrothermograph charts for recording temperature and relative humidity, especially in our storage areas. We have two storage areas, each run by a separate (and different) HVAC unit. By showing the charts over several months, we were able to convince our engineers that one of the units wasn't functioning properly. We've been able to work with the HVAC engineers to pinpoint what is malfunctioning, based on their readings of the charts. I check the charts every day to see if there are problems. Some are simple enough that our own engineers can fix. The chart paper is changed every week. We also have a few recording hygros in exhibit cases. These are awkward and time-consuming to change every week, but having that data is crucial when we're working on updating or changing our exhibits. We also use smaller T/RH monitoring devices in most of our exhibit cases. These don't record, so someone has to go around, look at each case, and manually record the T & RH. Another time-consuming task. We have individually controlled exhibit cases, so it's crucial for us to know the conditions in each one. I'd love to hear from others who are using dataloggers. Dataloggers sound simpler, but, I have to admit that I've been unable to decipher the technical jargon to make an educated investment in them yet. I had conservators warn against using them, at least as an initial recording device, because of the tendency to "forget" to download the data. That, and the fact that they only tell you what the conditions HAVE been, not what they are, so that if you see a problem on the chart, it's too late, it's already happened. It really is key to use the data you get from hygros. Even just having a record of the conditions is incredibly helpful when planning exhibits and working with conservators on the condition and treatment of artifacts. Yes, the work involved is time-consuming and boring, but worth it. Kate Desulis (312) 322-0821 phone Adler Planetarium & Astronomy Museum (312) 322-2257 fax 1300 S. Lake Shore Drive [log in to unmask] Chicago, IL 60605 URL http://astro.uchicago.edu/adler/