150 LIGHT SCIENCE FOR LEISURE HOURS. 



observations by the pupils of Galileo. These observa- 

 tions extend from 1655 to 1670, and show that the 

 minimum temperature was reached at that time on or 

 about February 12. Mr. Kussell, Government Astro- 

 nomer at Sydney, has pointed out that the same pecu- 

 liarity is observable in Australian registers. 



It was natural that in searching for a cause of 

 these remarkable anomalies of temperature, science 

 should have been led to look outside the earth. Forty- 

 three years have now passed since Adolph Erman threw 

 out, in the Poggendorf Annalen, the idea that the 

 sun's conjunction with the August meteors on February 

 7 and with the November meteors on May 12, might 

 explain the cold spells which occur in February and 

 May. He supposed that the ring of meteors through 

 which the earth passes in August is smaller than the 

 earth's orbit, so that, as the plane of the ring cuts the 

 plane of the earth's orbit in a straight line, passing 

 through the sun, and extending on one side to the 

 earth's place on or about August 11, this line must 

 extend on the opposite side to the place occupied by 

 the earth on or about February 7, passing through the 

 meteors before reaching the earth. The meteor ring, 

 according to this view, would lie between the earth 

 and the sun on or about February 7, and the earth 

 being in their shadow would be to a certain extent 

 chilled. So with the November meteors. The earth 

 would pass into their shadow, according to this 

 ingenious theory, on or about May 11 or 12. Hence 

 the * cold days in May.' 



