DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.20140#0051
III. THERMOMETERS AND GRAPHICAL REPRESENTATIONS.
Standards ; English and German Forms. Correction of the freezing point, alteration by time, by heat, by height.
Gen. Sabine's freezing point of the Mercury. My Thermometers without bulb for the Correction of the
Stem.
Considerations eor Meteorological Stations. Selection of the Hace; Thermometer in peripheric motion.
Registering Instruments. Scales employed. Range of the Thermometers. Table of Reduction.
Graphical Representations. Stampfer's Planimeter for taking means; my Revolving Scale for comparing variability
(and linear measurement in general).
STANDARDS; ENGLISH AND GERMAN FORMS.
Our instruments1 we had occasion to compare in full detail before our departure
with those of the Kew observatory; of the thermometers our two standards were made
by Newman ; I left them at the observatories of Calcutta and Madras before returning
to Europe.
In the Newman thermometers, the division was engraved upon the glass stem
itself; they reached from below the freezing point to above-the boiling point of
water; and also the variations within the scale were measured by calibration.2 They
were the basis for the determination of the corrections of the other instruments. The
form of the glass stem being used for the application of the division of the scale has
the advantage of perfectly excluding any alteration in mutual position of tube
1 The instruments used for the meteorological and physical observations are figured on a separate plate, to which
description notes are added; here I limit myself to some remarks in direct connection with the Thermometers.
2 The calculation of the corrections from the readings of the calibration has been developed with particular
accuracy by Bessel, Pogg. Ann., Vol. 6, p. 287; the more recent methods described by Egen, Pogg. 11, 529; 13,
46; and by Rudbers, Pogg. 40, 562, must be quoted on account of the facility of their application. — My
Newmans had the centigrade scale, with the boiling point, as generally for most of the standards, coinciding with
760 Millimeters of pressure. In many Fahrenheit thermometers the pressure adopted is 30 Eng. inches = 762 Mill.;
in the Reaumur thermometers the pressure frequently is 2S par. lines = 758 Millim. — In using thermometers for
measuring heights such differences become quite appreciable.
4*
Standards ; English and German Forms. Correction of the freezing point, alteration by time, by heat, by height.
Gen. Sabine's freezing point of the Mercury. My Thermometers without bulb for the Correction of the
Stem.
Considerations eor Meteorological Stations. Selection of the Hace; Thermometer in peripheric motion.
Registering Instruments. Scales employed. Range of the Thermometers. Table of Reduction.
Graphical Representations. Stampfer's Planimeter for taking means; my Revolving Scale for comparing variability
(and linear measurement in general).
STANDARDS; ENGLISH AND GERMAN FORMS.
Our instruments1 we had occasion to compare in full detail before our departure
with those of the Kew observatory; of the thermometers our two standards were made
by Newman ; I left them at the observatories of Calcutta and Madras before returning
to Europe.
In the Newman thermometers, the division was engraved upon the glass stem
itself; they reached from below the freezing point to above-the boiling point of
water; and also the variations within the scale were measured by calibration.2 They
were the basis for the determination of the corrections of the other instruments. The
form of the glass stem being used for the application of the division of the scale has
the advantage of perfectly excluding any alteration in mutual position of tube
1 The instruments used for the meteorological and physical observations are figured on a separate plate, to which
description notes are added; here I limit myself to some remarks in direct connection with the Thermometers.
2 The calculation of the corrections from the readings of the calibration has been developed with particular
accuracy by Bessel, Pogg. Ann., Vol. 6, p. 287; the more recent methods described by Egen, Pogg. 11, 529; 13,
46; and by Rudbers, Pogg. 40, 562, must be quoted on account of the facility of their application. — My
Newmans had the centigrade scale, with the boiling point, as generally for most of the standards, coinciding with
760 Millimeters of pressure. In many Fahrenheit thermometers the pressure adopted is 30 Eng. inches = 762 Mill.;
in the Reaumur thermometers the pressure frequently is 2S par. lines = 758 Millim. — In using thermometers for
measuring heights such differences become quite appreciable.
4*