[ 70 ] * 



In the cylindrical projedlion the countries on each fide of 

 the equator are conceived to be delineated on the furface of a 

 cylinder, cutting the fphere in two parallels, nearly midway 

 between the equator and the top and bottom of the map : The 

 meridians and parallels are right-lines, cutting each other at 

 right-angles, and the former obferve their due di fiance only on 

 the interfections of the cylinder and fphere : This projedlion is 

 evidently the befl for the tropical regions ; but, as it is not of 

 general application, and partakes of the perfedlions and imper- 

 fedlions of the conical, it is fufEcient to have mentioned it. 



Although it is thus evident that the area, refulting from 

 the fimple menfuration of every fpecies of map, however pro- 

 jedled, muft, (except the country reprefented be of fmall extent) 

 differ confiderably from the true area, yet there is reafon, I think, 

 to fufpedl that the generality of flatiflical writers have only- 

 performed the operation in the ufual way, and perhaps on 

 maps injudicioufly feledled, without taking any precaution to 

 corredl the errors which mufl inevitably arife from fuch a pro- 

 cefs ; at leaft the flrange inconfiflency obfervable in their tables, 

 with their want of candour, in not communicating to the public 

 their method and materials, fubje(5l them to this fufpicion. A 

 few, indeed, have given us fome numbers fufiiciently corredl, 

 but by what means they difcovered truth, as they are filent on 

 the fubje6l, we are ignorant. I fliall, therefore, make no apology 

 for offering the following method of nearly determining the true 

 areas of maps : It is, I believe, new, and will be found, 1 hope, 



fufficiently 



