Toronto Astronomical Society
Meeting Minutes - 1869 March 2
Regular Meeting Mar 2nd 1869
at the residence of Mr. Potter, Optician
Present:- Mr. Winder, President, Messrs Elvins, Potter, Brunt, Turnbull & Clare, Mr. Long, the member proposed at previous meeting, and as visitors, Mr. Faircloth & Miss Winder.
The minutes of previous meeting were read and confirmed.
Mr. Long was unanimously elected a member of the society.
Mr. Brunt called attention to some celestial phenomena suitable for observation during the month - to Jupiter, Mars, Saturn & Neptune. He especially suggested the making of observations on the Zodiacal Light, to be reported at next meeting - a careful examination of this phenomenon being expected to throw some light upon the theory of comets.
The paper of the evening was read by Mr. Elvins; Subject "The Moon - its physical constitution and motions"
Mr. Elvins glanced at the position of the moon in the universe; referring to the motion of the solar system in space, the motion of the earth round the sun, and that of the moon round the earth. He took a rapid survey of the lunar surface, illustrating his description by means of Rutherford's photographs and Nasmyth's drawings shown with the magic lantern. In describing lunar motion Mr. Elvins contended that the moon has but two motions, one round the sun in common with the earth and one round the earth itself - the latter performed in a lunar month. He discarded the idea of the moon revolving on an axis of its own, the centre around which it revolves not being within itself, but at the earth's centre. He contended that the following results were the necessary consequences of the moon's motion - first, the elongating of the moon's body by centrifugal force, so as to render it, not spherical, but elliptical in shape, having its longer axis pointing toward the earth; second, that by the action of centrifugal force, fluids and liquids must be thrown to the opposite side of the moon; a gradual lowering of temperature as the atmosphere became less dense would follow, until all vapours would have been deposited as snow on the lunar surface and the seas converted into ice, the hole surface being possibly covered with ice as with a coat of varnish. He contended that the different rate of motion between the nearer and most distant part of the moon is the cause of libration in longitude, and that the sun's attraction changes the position of the major axis of the moon's elongated body, causing the point nearer the earth to be turned upward when the sun is above the plane of the moon's orbit, and downward when the sun is below that plane, causing libration in latitude.
Mr. Elvins submitted that as these results must necessarily follow on the supposition of his views being correct, the generally received notion of the equable motion of the moon on an axis combined with an unequal one i her orbit is not necessary to account for libration in longitude; nor is the inclination of the lunar axis of rotation to the plane of the moon's orbit necessary to account for the libration in latitude.
Moved by Mr. S. Clare & seconded by Mr. Long that the thanks of the meeting be tendered to Mr. Elvins for his elaborate paper. Passed.
Moved by Mr. Brunt & seconded by Mr. Long that an adjourned meeting be held at the residence of Mr. Elvins on this day fortnight Mar 16th to afford an opportunity of discussing Mr. Elvins' paper. Passed.
Next monthly meeting to be held at Mr. Brunt's, April 6th 1869.
On motion by Mr. Brunt seconded by Mr. Elvins the meeting adjourned till the 16th March inst.