POPL T LAR ASTRONOMY 



61 



m this y^ar of our Lord 1910, with the 

 daily newspaper ready to disseminate 

 the splendid results of modern science, 

 gives some inkling of the dread that 

 these monsters of the sky must have 

 caused in years gone by. 



This is being written (May 14, before 

 we pass through the tail of the comet on 

 May 18), with the confident expectation 

 that we shall be alive to tell the tale 

 after that day. 



carbon, together with the cyanogen band, 

 the strongest in the whole spectrum. In 

 addition the sodium lines appeared, but 

 not so prominently as in Comet A, 1910. 

 The strange behavior of the spectrum 

 was that though the cyanogen band was 

 strong in the head of the comet, it was 

 lacking in the tail. Moreover, the spec- 

 troscopic test is an excessively delicate 

 one, capable of detecting minute quanti- 

 ties of material. For instance, if a grain 



Evening SkyMap for JUNE 



JUNE Moon Phases 

 newmoon.june. 7. 

 First Qtr., June 14. 

 FullMoon.JUNE22 

 LA5TQtr.,JUNE29. 



Columbia 

 Univ^ijy. 



FACE SOUTH AND "* 

 HOLD THE MAP OVER "** 

 YOUR HEAD-THE TOP 

 NORTH. AND YOU WILL SEE 

 THE STARS AND PLANETS 

 JUST AS THEY APPEAR 

 IN THE HEAVENS 



SOUTH 



DATES AND 

 POSITION OF 

 HALLEYS COMET 



ARE GIVEN ON THE 

 MAP FOR JUNE IN 



WESTERN EVENING SKY. 



If the truth were wholly known, there 

 was no danger whatever from the cyano- 

 gen in the tail. The composition of the 

 comet and its tail is made known by the 

 spectroscope. Early in May the spectra 

 were of remarkable interest. Plates 

 taken at Yerkes, Lick and Flagstaff ob- 

 servatories agree in showing a strong 

 continuous spectrum with faint traces of 

 Fraunhofer lines due to reflected sun- 

 light, with strong bands due to hydro- 



of ordinary salt were divided into a mil- 

 lion parts, and one of these placed in a 

 gas flame, the spectrum would display 

 the certain badge showing the presence 

 of sodium, two strong lines in the yellow 

 part of the spectrum. 



To harm life on the earth, the cyano- 

 gen would have to be mixed with the 

 air in comparatively large quantities. 

 The small amount of this poisonous gas 

 in the tail as revealed by the spectro- 



