502 SCIENTIFIC RECREATIONS. 



rising and setting, as it were, in various places (we must remember we have 

 concentrated the suns rays, not a lamp, upon the globe). The places on 

 the right, if the observer be placed facing the sun, will come out of the 

 shade, and those on the left will enter it. The former are then really 

 enjoying the sunrise, and the others are actually witnessing his setting. 



The globe represented, making the double revolution of our planet 

 in the year, will reproduce all the actual phenomena of day and night as 

 taking place on the earth itself if we stand at a little distance so as to 

 observe it all at once. 



Fig. 634. A simple terrestrial globe. 



Of course, the employment of this simple apparatus should not exclude 

 more complicated ones,, for the former can only be used on a fine bright 

 day. But the advantage claimed for it is that in it we can imitate nature 

 exactly. Illuminated, as it is, by the real sun, the portions of light and 

 shade are indicated by the rays and not by a metallic circle. 



In order that the line of demarcation may be exactly defined, it will 

 be necessary that the sun's rays be concentrated upon the globe, and that 

 no lateral or vertical light be admitted. The curtains should therefore be 

 so arranged, and the blinds pulled down to a certain point, and if the stand 

 or support be painted black it will be found an advantage. If the globe be 



