THE USE OF THE TERRESTRIAL GLOBE. 295 



ed from the greater, if both places are on the same side LECT. 



VIII & IX. 

 of the equator, or both latitudes added together, if they ^*^ -^, 



are on different sides of it, is the difference of latitude 

 required. And the number of degrees contained be- 

 tween these places, reckoned on the equator, when they 

 are brought separately under the brazen meridian, is 

 their difference of longitude, if it be less than 180 : but 

 if more, let it be subtracted from 360, and the remainder 

 is the difference of longitude required. Or, 



Having brought one of the places to the brazen meri- 

 dian, and set the hour index to XII, turn the globe 

 until the other place comes to the brazen meridian, and 

 the number of hours and parts of an hour, passed over 

 by the index, will give the longitude in time ; which may 

 be easily reduced to degrees, by allowing 15 degrees 

 for every hour, and one degree for every four minutes. 



N. B. When we speak of bringing any place to the 

 brazen meridian, it is the graduated side of the meri- 

 dian that is meant. 



PROBLEM IV. 



Any place being given, tojind all those places that have the 

 same longitude or latitude with it. 



Bring the given place to the brazen meridian, then 

 all those places which lie under that side of the meri- 

 dian, from pole to pole, have the same longitude with 

 the given place. Turn the globe round its axis, and all 

 those places which pass under the same degree of the 

 meridian that the given place does, have the same lati- 

 tude with that place. 



Since all latitudes are reckoned from the equator, 

 and all longitudes are reckoned from the first meridian, 

 it is evident, that the point of the equator which is cut 

 by the first meridian, has neither latitude nor longitude. 

 The greatest latitude is 90 degrees, because no place 

 is more than 90 degrees from the equator. And th? 



