Unpublished paper, 'On the lunar variations of magnetic declination at Bombay [Mumbai, India]' by Charles Chambers

Description

This paper is in continuation of that 'On the Solar Variations of Magnetic Declination at Bombay', published in volume 159 of Philosophical Transactions; but the discussion is confined to the observations of the years 1861 to 1863, which alone have as yet been reduced. The point of principal interest brought out in the discussion is that whilst the mean lunar-diurnal variation is of the ordinary character, having as its principal feature a double oscillation in the lunar day, its range is very small as compared with the several ranges of the lunar-diurnal variations when the sun and moon have several specific varieties of relative position; and moreover, although in those latter variations the double oscillation is generally preserved as a main feature, correspondence of phase in the representative curves is as generally absent; and in some cases the curves are, whilst systematic, altogether different in character from the mean lunar-diurnal variation curve. The semiannual inequality in the lunar-diurnal variation, whilst it is as definitely systematic, has twice the range of the mean lunar, diurnal variation; and it is also subject to remarkable modifications which accompany changes of phase of the moon.

Annotations in ink throughout. Marked on front as 'Archives Jan 7/75'. Includes two plates of graphs showing lunal diurnal variation of declination.

Subject: Magnetism / Astronomy

Received 4 December 1871. Read 1 February 1872.

Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 20 of the Proceedings of the Royal Society as 'On the lunar variations of magnetic declination at Bombay'.

Reference number

AP/55/3

Earliest possible date

1871

Physical description

Ink on paper

Page extent

12 pages

Format

Diagram
Manuscript