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HARDWICKE'S SCIENCE-GOSSIP. 



ASTRONOMY. 

 By John Browning, F.R.A.S. 



THE Reverend S. J. King, director of Stonyhurst 

 Observatory, recently delivered a very in- 

 teresting lecture at the Royal Institution, on the Solar 

 Surface during the last ten years. He had taken a 

 great number of drawings of sun-spots, and, allowing 

 for the effects of foreshortening, in this respect his 

 drawings are more accurate than photographs. 

 Although he had to contend with the bad climate of 

 Lancashire, he succeeded in making on an average 

 258 drawings a year. The period of minimum sun- 

 spots will be reached shortly, as the decrease has been 

 going on now for about three years. 



The area of the spots sometimes changed as much 

 as one hundred million square miles in a day. The 

 magnetic records of terrestrial magnetism follow the 

 rate of such change with great regularity. The 

 maximum of sun-spots and magnetic swing occurred 

 in the year 1882. 



In concluding, the lecturer suggested that sun-spots 

 might be caused by meteoric streams. 



The annual visitation of the Royal Observatory, 

 Greenwich, took place on June 1st. A pair of glass 

 discs twenty-eight inches in diameter have been com- 

 pleted by Chounce for the new refractor, and a special 

 telescope, which will be a photographic refractor of 

 thirteen inches' aperture, will be made to enable 

 Greenwich to take part in the great photographic 

 chart of the heavens. 



At the last meeting of the Royal Astronomical 

 Society, Rev. J. Roberts read a paper on a photograph 

 of the Nebula 51 Messier taken with an exposure of 

 four hours. Mr. Roberts pointed out that the nebula 

 -shows a spiral structure, and that lines of stars seem 

 to follow the trend of.the spiral streams, 



Mr. Frank McClean read a paper on Parallel 

 Photographs of Spectra of the Sun, of Iron, and of 

 Iridium from H to near D. Mr. McClean pre- 

 sented to the Society a photograph of the solar 

 spectrum on the scale of Angstrom's charts of the 

 normal solar spectrum. A photograph of the iron 

 spectrum is shown on one side of this, and a photo- 

 graph of the spectrum of iridium obtained by the 

 electric spark on the other. The coincidences of the 

 iron lines and iridium lines with solar lines is beauti- 

 fully shown, and the E line is double. The scale of 

 these piiotographs is bigger than any photograpiis of 

 metallic spectra which have previously been pub- 

 lished. 



The Astronomer Royal read a paper on the results 

 of measures of sun-spots, which was accompanied by 

 a diagram showing how sun-spots are distributed in 

 latitude. 



Mr. Common read a paper on the white spot on the 

 ring of Saturn, observed by Dr. Tenby, which has 

 been easily seen during the last few weeks. Mr. 

 Common considers that the white spot is an optical 



Rising, Southing, and Setting of the Principal Planets 

 in July. 



illusion, being an effect of contrast with the broad 

 shadow of the ball of the planet on the ring. 



July 1st : The earth will beat the greatest distance 

 from the sun, 9 hours aft. 



July 12 : Partial eclipse of the moon, partly visible 

 at Greenwich. The first contact will take place with 

 the shadow at 7 hrs. 43 min., aft. Middle of the 

 eclipse 8 hrs. 54 min. aft., and last contact with 

 shadow at 10 hrs. 5 min. aft. The moon rises at 

 Greenwich 40 min. before the middle of the eclipse, 

 and about half the moon's surface will be eclipsed. 



There will be no occultations of interest in July. 



Mercury will be a morning star. 



Venus will be a morning star. 



Mars will be a morning star. 



Saturn will be an evening star, and will be in Leo 

 near Regulus. 



THE DEVELOPMENT OF THE COLOURS 

 OF FLOWERS THROUGH INSECT- 

 SELECTION. 



MR. • EDWARD H. ROBERTSON'S paper 

 with the above title in the current number 

 of Science-Gossip seems to call for a few remarks. 



In the first place, I am surprised to see the old 

 argument against the insect-selection theory (used by 

 Mr. Bulman in October, 1887) again appearing : 

 namely, the argument from the existence of bright 



