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Mag.

NOVA AQUILAE, NO. 3

By R. M. MOTHERWELL

THE following magnitudes of Nova Aquilae are photographic
and were determined by the extra-focal method, using a
6-inch doublet of 30-inch focus. Seed 30, G.E. plates were used
throughout, the plate being set 5.5 mm. outside the focus. The
star BD. + 1o, 3766 was used as the comparison star in all the
measures. It is listed in "Harvard Annals" as of magnitude 5.04
and spectral type B5, a correction of -.12 of a magnitude being
applied to reduce it to the photographic magnitude (see Harvard
Annals, 80,151). When the Nova became sufficiently faint, longer
exposures were given, and a second comparison star, BD. — 1o,
3559, was used also. The agreement between the magnitudes
derived from the two comparison stars was good, but the results
given are those derived from measures using BD. + 1°, 3766, as
the other star could not be used until the latter part of August.
A comparison of these magnitudes with the visual estimates shows
a difference of nearly one magnitude about June 20, the visual

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magnitude being brighter; while in the latter part of July the photographic magnitude is brighter by about half a magnitude. Judging by negatives obtained at this observatory in June with stained plates, this difference is due to the marked intensity of the Ha line.

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MEETINGS OF THE SOCIETY

November 26, 1918, in the rooms, 198 College A. F. Miller, in the chair.

AT TORONTO

The Society held its regular meeting
Street, at 8 p.m., the President, Mr.

Mr. Reginald Langton Morris, Halifax, N.S., and Mr. F. J. Robertson, Seebe, Alberta, were elected members of the Society.

Under "observations", Mr. W. E. W. Jackson mentioned that there are a great many sunspots at present. Mr. A. F. Miller added that, notwithstanding the sunspots, there are comparatively few auroras visible in this locality. He also mentioned that Nova Aquilae is now far to the west, and is difficult to see. As it has become nebulous, it is much fainter than it was, and it will soon be invisible until next May, if visible then at all. Its color is a gieenish white, and it is still possible to see the spectrum. It is now probably between the seventh and the eighth magnitudes.

J. B. Fraser, M.D., Toronto, read the paper of the evening on "Astronomy of the Seventeenth Century", which he prefaced by describing the conditions of ordinary life at that time. For floors in the houses they used rushes; for beds, pallets of straw; for stoves, they used fireplaces. The whole of Europe was steeped in superstition. Witches were burned, and as a cure for chin cough (which is now called whooping cough), a child that had it was passed under a donkey's belly at full moon. Astrology and astronomy were combined together. The different diseases to which human flesh is heir, came under the different constellations of the sky. Traces of this belief still remain in our language, as,

for example, the term "cancer", which was believed to have its origin under that constellation.

Astronomy was utilized for their own personal purposes of physical health to the utmost degree; prognosis of recovery was always given by the constellations. The two killing planets were Mars and Saturn, and they were especially dangerous when near together. A doctrine of this sort left its impression on language, as in the word "lunacy", and in some other words. Omens drawn. from the stars and manipulated under psychic influences, aided or retarded recovery. Harvey's discovery of the circulation of the blood was strongly opposed by astrologers and medical practitioners of the time, but it has "won out", and medicine is now divorced from astronomy.

He next referred to the improvements in the telescopes of the seventeenth century, and to their quadrants and sextants; also to their views on the aurora borealis, and devoted the remainder of the paper to the lives and works of individual astronomers of that century, viz., Kirsch, a German; Cassini, an Italian; Newton, whose theory was bitterly opposed by the clergy of the day; Kepler, of Wurtemburg, who in 1599 went to Prague, where he aided Tycho and published his famous "laws"; Halley, who made the correct prediction of the famous comet named after him, and who wrote papers on the magnet and the magnetic needle; Flamstead, who made the first British catalogue of the stars; Hevelius. of Danzig; Gassendi, who wrote of the transit of Mercury, and in 1631 was the first to observe one; Huyghens, who was born at the Hague, in 1639, and who put forward the undulatory theory of light; Galileo, who was born in 1564, and discovered the four satellites of Jupiter in 1610, and who tested the laws of motion from the Tower of Pisa; Robert Hooke, who was born in the Isle of Wight, and who discovered sunspots and their changes.

The main features of seventeenth century astronomy were the disuse of astrology and the rise of astronomy in its place. attended by much opposition from the clergy.

A. F. HUNTER,

Recorder.

AT MONTREAL

December 12, 1918, The Montreal Centre of the Royal Astronomical Society of Canada met on the evening of December 12th in the Engineering Building of McGill University, Mgr. C. P. Choquette, the President, in the chair. There was a fair attendance of members and visitors.

The President gave a lecture on "The Measurement of the Distances of the Heavenly Bodies." He began by discussing the various units of length employed in measuring distances, and explained the nature of parallax by diagrams and illustrations. He took up the question of the measurement of the earth's radius, and having ascertained this, the moon's parallax and distance were calculated.

The phenomenon of the transit of Venus and how it solves the question of solar parallax was very clearly explained and an actual computation made.

A hearty vote of thanks was presented to the lecturer by Mr. James Weir, B.Sc.

Mr. George Sample proposed the formation of a question bureau to assist members in the solution of various problems that present themselves from time to time. This was supported by Capt. Dr. Fournier and by Miss Mable Ellicott and agreed to by the members present.

The following were admitted into the Society, thirteen in all :
Joseph Edgar Guimont.

Francis E. M. Robinson, B.A.

Rev. A. J. Oakley.

E. Charles Carpenter.

H. E. Markham.

H. A. Ewart.

Rev. Principal Brandt, D.D.

Wm. Thos. Walmsley.

Miss Mable Ellicott.

Prof. Conrad Maureau.

Rev. James Ereaux,

R. T. Gaunt.

Hon. N. Perodeau, K.C.

W. T. B. CROM BIE,

Secretary.

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