TO KNOW THE STARRY III'LVVENS 



367 



are but few good observing nights in the 

 whole year. When a really bright night 

 appears, that is the time for serious work. 

 Place your name on our waiting list and 

 we will notify you l)y telephone when a 

 propitious time arrives. We shall then 

 be glad to have you accept the invitation 

 and we shall be happy to do all in our 

 pozver to make your visit profitable to yon, 

 but come only one or two at a time .if you 

 please. 



The Heavens Brought Within Doors. 



There are some disadvantages in 

 studying the heavens. The most im- 

 portant is the fact that in the entire 

 year there are but few^ ideal starry 

 nights. The second is that of these few 

 favorable nights the best are in the win- 



In Chicago all these difficulties have 

 been overcome so far as they can be 

 overcome by any artificial device. At 

 The Chicago Academy of Sciences has 

 been placed the Atwood Celestial 

 Sphere that gives a miniature reproduc- 

 tion of the heavens and the stars as 

 they are there located. The student or 

 the casual visitor can walk inside of 

 the heavens and see the stars under 

 comfortable conditions of situation and 

 temperature. It is to be presumed that 

 this arrangement prevents visitors 

 from stamping during the first minute 

 and saying, "Oh, my feet are freezing," 

 and shivering the next and saying, "I 

 can't stand this. It is too cold." 



But to be within this celestial sphere 

 is like following the showman around 



AN ATWOOD CELESTIAL SPHERE. 



ter when the constellations shine at 

 their brightest. There is another dis- 

 advantage. People in the cities cannot 

 study the heavens on account of the 

 electric lights, the smoke and the lack 

 of proper localities from which the 

 heavens may be seen from horizon to 

 horizon. 



the menagerie of a traveling circus. 

 The exhibitor caries a small electric 

 light at the end of a rod and with it 

 easily points out the stars. Mr. At- 

 wood. the inventor, writes as follows : 

 "When the sphere was first opened 

 to the public, the popular demand for 

 admission was so great that a profes- 



