1869 Apr 6

Toronto Astronomical Society
Meeting Minutes - 1869 April 6

Regular Meeting April 6th 1869
at Mr. Brunt's residence, York George Street.

Present:- Mr. Winder, President, Messrs Turnbull, Brunt, Ridgway, Elvins and Clare.
Visitor Mr. Wm. Thompson

Mr. Brunt read a paper by R. A. Procter B.A., F.R.A.S. on "The great Nebula in Argo." The article has reference to two remarkable communications lately addressed from southern observers to astronomers in the north. One, by Mr. Abbott, of Hobart Town, the other by Lieut. Herschel, son of Sir John.

In regard to the nebula in Argo, "the glory of the southern skies" -- Sir John Herschel while at the Cape directed a large share of attention to it, and described it as a diffuse mass of cloudy light extending over a space of about 6 times as large as the apparent surface of the moon. He remarks that the nebula could not be distinguished by the naked eye even on the darkest night, and also that he saw no reason to suspect that any changes of position wee taking place among the fixed stars which are strewn over the nebulous background. Mr. Abbott finds that a great increase has taken place in the brightness of the nebula - so much so that it can now be clearly distinguished in twilight so strong as to obliterate all stars below the third magnitude. The changes which have taken place in the figure of the nebula are still more startling. There is not resemblance between two pictures representing the appearance of the nebula as seen in 1863 and in 1868 (Feb 13) by Mr. Abbott, nor between either of these and Sir John Herchel's drawing. Taking the [unreadable note between lines here] well-known variability of the star Eta Argus in connection with the variability of the nebula in Argo, the probability is suggested that the two objects are connected.

The same month which brought Mr. Abbott's communication brought also that of Lieut. Herschel's announcing that the spectrum of the great nebula in Argo having been found to consisting of a few bright lines, the nebula must be luminous gas or vapour. It will become then an interesting problem for astronomy to solve, by what strange sympathy these stars are associated with the nebula, that as it varies in figure they vary in their distribution [unreadable note between lines here]. How shall the waxing and waning light of the nebula be accounted for and the accordance which these changes exhibit with the waning and waxing light of the star Eta Argus? Lastly, what are the forces under whose influence the enormous mass of vapour which constitutes the nebula are wafted to and fro like clouds before a shifting wind?

In reference to Lunar changes
Mr. Elvins called attention to the appearance of the spot Messier in the Sea of Fecundity as observed by him on the 18th and 20th of March. On the 18th (the moon being about 4 or 5 days old) the craters were plainly seen, were quite round, and the one nearest the western edge of the moon was much smaller than the other from which the bright rays streamed. The comparative diameters were about 1 to 3 showing a difference when compared with early observations. On the 20th March, the shadows in both craters had entirely disappeared. Both craters were now seen as white spots, precisely similar in brightness, shape & size. He had subsequently observed them twice with similar results. Mr. Elvins concluded that if the early observers spoke of the crater proper, a change had certainly taken place, but if they, speaking more loosely, referred to the spot when under high illumination then there had been no change.

Mr. Turnbull suggested the propriety of having a synopsis of the matters of interest contained in the Astronomical Register read at the monthly meetings.

Mr. Turnbull reported favorably of his progress with his Reflector.

Mr. Winder referred to the interest manifested by many in Toronto in spectroscopic research. He was now able to throw the spectra of various metals on a canvas so as to exhibit them to a large audience. He also stated that chemical plates had been prepared by which the spectroscope could now be photographed.

Mr. Elvins read an extract referring to the comet shortly to appear.

Mr. Elvins Turnbull thought he should be able to give his paper on the eclipse by the June meeting.

Mr. Ridgway promised a paper on the figure of the earth for an early meeting, Mr. Brunt promised a paper on the Tides.

The thanks of the Club, on motion of Mr. Turnbull, seconded by Mr. Ridgway, were given to Mr. Brunt for the reading of Mr. Proctor's paper.

Next meeting to be at Mr. Elvins on the 4th Ap May.

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