EXPLANATION OF THE PLATES. xli 



call in queftioii thefc dimenfions, for they are taken from 

 the lad obfervations of Captain Cooky who made the tour of 

 this cupola during their Summer. 



The ices of the North Pole are much more extenfive, 

 becaufe they are reprefented in their Winter. On both the 

 one and the other, a creft is exprefled, of about twenty 

 leagues of elevation, at the Poles. I fliall not here repeat 

 what I have already faid refpe6ling the height of thofe ices 

 which are difcovered floating at the extremities of their cu- 

 polas, the elevation of which extends to twelve, nay, to 

 fifteen hundred feet. I was exceedingly defirous of pro^ 

 curing a reprefentation, around thefe ices, of an irradia- 

 tion, or kind of Aurora Borcal'is, which might have ren- 

 dered perceptible their circular extent, and have heightened 

 the pidurefque efFe£l of the Globe, by rendering it's Poles 

 radiant ; for the South Pole, too, emits nodlurnal corufca- 

 tions, as Cook obferved ; and it appears that thefe glories 

 owe their origin to the ices. But M. Moreau the younger, 

 who made the drawings for the plates of this Work, and 

 particularly thofe under review, with all the intelligence 

 and complaifance which characterize him, made me fen- 

 fible that the Chart had not a field fufficiently ample. He 

 has, in other refpefts, rendered thefe polar ices abundantly 

 luminous, to make them diftinguifhable, without eclipfing 

 the contours of the iflands, and of the Continents which 

 they cover. 



As to the Atlantic channel, you can eafily diftinguifli in 

 it, the prominent and the retreating parts of the two ContU 

 nents, in correfpondence with each other. If to this you 

 add the fmuofity of it's fource to the North, which feems to 

 purfue a ferpentine progrefs round our Pole, and it's wide 



and 



