THE USE OF THE TERRESTRIAL GLOBE. 297 



The globe remaining in the same position, set the LECT. 

 hour index to the upper XII on the horary circle, and 

 turn the globe until the index comes to the lower XII ; 

 then, the place which lies under the meridian, in the 

 same latitude with the given place, is the periacci requir- 

 ed. Those who live at the poles have no periccci. 



As the globe now stands (with the index at the lower 

 XII) the antipodes of the given place will be under the 

 same point of the brazen meridian where itsantasci stood 

 before. Every place upon the globe has its antipodes. 



PROBLEM VI 



To find the distance between any two places on the globe. 



Lay the graduated edge of the quadrant of altitude 

 over both the places, and count the number of degrees 

 intercepted between them on the quadrant ; then mul- 

 tiply these degrees by CO, and the product will give the 

 distance in geographical miles : but to find the distance 

 in English miles, multiply the degrees by 69i and the 

 product will be the number of miles required. Or 

 take the distance betwixt any two places with a pair of 

 compasses, and apply that extent to the equator ; the 

 number of degrees, intercepted between the points of 

 the compasses, is the distance in degrees of a great cir- 

 cle ;" which may be reduced either to geographical 

 miles, or to English miles, as above. 



Nute 81. Any circle that divides the globe into two equal parts, is 

 called a great circle, as the equator or meridian. Any circle that di- 

 vides the globe into two unequal parts (which every parallel cf lati- 

 tude does) is called a lesser circle. Now as every circle, whether great 

 or small, contains 360 degrees, and a degree upon the equator or me- 

 ridian contains 60 geographical miles, it is evident that a degree of 

 longitude upon the equator is longer than a degree of longitude upon 

 any parallel of latitude, and must therefore contain a greater number 

 of miles. So that, although all the degrees of latitude are equally 

 long upon an artificial globe (though not precisely so upon the earth 

 it-self) yet the degrees of longitude decrease in length, as the latitude 

 increases, but not in the same proportion. The following table shews 



