THE USE OF THE TERRESTRIAL GLOBE. 301 



observe what degree of the meridian stands over it ; L ECT. 



for that is the sun's declination, reckoned from the yni&IX 



,~>- 



equator. 



PROBLEM XI. 



The day of the month being given, to find all those places 

 of the earth over which the sun will pass vertically on 

 lhat day. 



Find the sun's place in the ecliptic for the given day, 

 and having brought it to the brazen meridian, observe 

 what point of the meridian is over it ; then turning the 

 globe round its axis, all those places which pass under 

 that point of the meridian, are the places required : for 

 as their latitude is equal, in degrees and parts of a 

 degree, to the sun's declination, the sun mast be di- 

 rectly over head to each of them at its respective noon. 



PROBLEM XII. 



A place being given in the torrid zone,** to Jind those ttoo 

 days of the year, on which the sun shall be vertical to 

 that place. 



Bring the given place to the brazen meridian, and 

 mark the degree of latitude that is exactly over it on 

 the meridian ; then turn the globe round its axis, and 

 observe the two degrees of the ecliptic which pass ex- 

 actly under that degree of latitude : lastly, find on the 

 wooden horizon, the two days of the year on which 



Note 82. The globe is divided into five zones ; one torrid, two temperate, 

 and two frigid. The torrid zone lies between the two tropics, and is 47 

 degrees in breadth, or 23 on each side of the equator : the temperate 

 zones lie between the tropics and polar circles, or from 23J degrees of 

 latitude, to 66|, on each side of the equator ; and are each 43 degrees in 

 breadth . lift frigid zones are the spaces included within the polar circles, 

 which being each 23^ degrees from their respective poles, the breadth of 

 each of these zones is 47 degrees. As the sun never goes without the 

 tropics, he must every moment be vertical to tome place or other in the 

 torrid zone. 



