8o LIGHT SCIENCE FOR LEISURE HOURS. 



In an opera-glass this phenomenon is yet more easily 

 recognisable. A very small telescope exhibits the 

 cause of the peculiarity, for it is at once seen, that 

 what seemed a star is in reality a mass of small stars 

 intermixed with a diffused nebulosity. 



It is a very remarkable circumstance that Galileo, 

 whose small telescope, directed to the clear skies of 

 Italy, revealed so many interesting phenomena, failed 

 to detect 



That marvellous round of milky light 

 Below Orion. 



It would not, indeed, have been very remarkable if he 

 had simply failed to notice this object. But he would 

 seem to have directed his attention for some time 

 especially to the region in the midst of which Orion's 

 nebula is found. He says : ' At first I meant to de- 

 lineate the whole of this constellation ; but on account 

 of the immense multitude of stars being also hampered 

 through want of leisure- -I left the completion of this 

 design till I should have another opportunity.' He 

 therefore directed his attention wholly to a space of 

 about ten square degrees, between the belt and sword, 

 in which space he counted no less than four hundred 

 stars. What is yet more remarkable, he mentions the 

 fact that there are many small spots on the heavens 

 shining with a light resembling that of the Milky Way 

 (complures similis coloris areolce sparsim per cethera 

 subfulgeani) ; and he even speaks of nebulae of this 

 sort in the head and belt and sword of Orion. He 

 asserts, however, that by means of his telescope, these 



