DOI Page / Citation link:
https://doi.org/10.11588/diglit.20140#0072
48 the daily period of temperature.
partly dry, occasionally black soil, now dense fanning grass — made them incom-
parable, arbitrary. Also the nature of the instrument, for instance the glass being
unusually strong or greenish, may essentially modify such readings.
The instrument, when imperfect, has chiefly the quality of making such readings
too low by being not delicate1 enough; slow instruments will not become sufficiently
warm at the time of the maximum; it is true, they will not become either sufficiently
cool during the opposite period; but this, though limiting their error for readings
such as the daily means, is no amelioration here, where the maximum is what we
most want to know. The personal examination of the different stations has shown
readings too low to be more frequent than those where they were overheated by too
great vicinity to dry black ground; whilst for the temperature in the shade the case
is the opposite one.
The visit, however, of the various provinces now described also allowed me
to find for every one of them data fairly comparable, and those are added, together
with the tables of absolute extremes in the shade,2 to the groups I formed; the
experimental series of observations we made during our own stay in the various
regions are to follow, together with the determinations of transparency and intensity
of light from which they may not well be separated; but the general results of the
observations of plain insolation I preferred putting together already here to
illustrate some of the principal causes of the modification of temperature. The
curves by which the results are represented are figured on Plate 4 of the Meteor-
ological Atlas; the numerical values of the fundamental tables can be considered as
the mean of the reading in the early afternoon of every day, supposing the sky to
have been so unclouded as to allow a distinct shadow to be thrown. If between
Noon and 4h p.m. no moment sufficiently clear presented itself, no observations were
1 This is quite analogous for instance to the circumstance that the temperature of the insolated ground does
not become either as hot or as cool at some depth as it will become on the very surface.
2 Also in the tables of the Parliamentary publication I have met to my great pleasure the readings of several
of the thermometers I had put up. As here the mean did not require any particular care in the combination,
if only days where no insolation was observed remained excluded, such values could be entered into my tables with
preference which were observed after my visit of the respective places, though I had not received as yet the detail
of the readings. I may be allowed to add, however, as then easily such mistakes can be avoided in official reports,
that in the papers I had received from the Medical Board the means sent in—happily together with the original
reading, day by day—had been formed so that days where no insolation could be observed had been entered too
in the divisor, viz., they were introduced as if 0° Fahr., or alias some 100 degrees below the temperature of the
air in shade had been read on such days.
partly dry, occasionally black soil, now dense fanning grass — made them incom-
parable, arbitrary. Also the nature of the instrument, for instance the glass being
unusually strong or greenish, may essentially modify such readings.
The instrument, when imperfect, has chiefly the quality of making such readings
too low by being not delicate1 enough; slow instruments will not become sufficiently
warm at the time of the maximum; it is true, they will not become either sufficiently
cool during the opposite period; but this, though limiting their error for readings
such as the daily means, is no amelioration here, where the maximum is what we
most want to know. The personal examination of the different stations has shown
readings too low to be more frequent than those where they were overheated by too
great vicinity to dry black ground; whilst for the temperature in the shade the case
is the opposite one.
The visit, however, of the various provinces now described also allowed me
to find for every one of them data fairly comparable, and those are added, together
with the tables of absolute extremes in the shade,2 to the groups I formed; the
experimental series of observations we made during our own stay in the various
regions are to follow, together with the determinations of transparency and intensity
of light from which they may not well be separated; but the general results of the
observations of plain insolation I preferred putting together already here to
illustrate some of the principal causes of the modification of temperature. The
curves by which the results are represented are figured on Plate 4 of the Meteor-
ological Atlas; the numerical values of the fundamental tables can be considered as
the mean of the reading in the early afternoon of every day, supposing the sky to
have been so unclouded as to allow a distinct shadow to be thrown. If between
Noon and 4h p.m. no moment sufficiently clear presented itself, no observations were
1 This is quite analogous for instance to the circumstance that the temperature of the insolated ground does
not become either as hot or as cool at some depth as it will become on the very surface.
2 Also in the tables of the Parliamentary publication I have met to my great pleasure the readings of several
of the thermometers I had put up. As here the mean did not require any particular care in the combination,
if only days where no insolation was observed remained excluded, such values could be entered into my tables with
preference which were observed after my visit of the respective places, though I had not received as yet the detail
of the readings. I may be allowed to add, however, as then easily such mistakes can be avoided in official reports,
that in the papers I had received from the Medical Board the means sent in—happily together with the original
reading, day by day—had been formed so that days where no insolation could be observed had been entered too
in the divisor, viz., they were introduced as if 0° Fahr., or alias some 100 degrees below the temperature of the
air in shade had been read on such days.