Hygrothermographs

In Instance 12:7, Sean Harrison asks for experiences with various
hygrothermographs, in comparison with ACR SmartReaders.

While I am not familiar with the hygrothermographs he mentions, I
have been using SmartReaders for eight or nine years and can
recommend them without hesitation.  They have proved very reliable,
and unlike hygrothermographs they do not need new charts, new pens
and new batteries at regular intervals.  Although one SR2 costs
about as much as two hygrothermographs, each logger can be fitted
with an extension probe so that you can monitor in two places with
one logger.  In addition they are small and inconspicuous so that
they can be concealed in galleries and inside display cases. Because
they produce data in digital form it is easy, either by using ACR's
own software or by exporting the data to a spreadsheet, to calculate
means, maxima and minima and parameters such as water vapour
pressure and dewpoint.  The only drawback is that you do not have an
immediate visual indication of the temperature and RH.

    (PS. Normal British usage is "thermohygrograph", while normal
    American usage appears to be "hygrothermograph".  Is there a
    reason for this?)

Barry Knight
English Heritage
London

                                  ***
                  Conservation DistList Instance 12:10
                  Distributed: Tuesday, July 14, 1998
                       Message Id: cdl-12-10-010
                                  ***