EXPLANATION OF THE PLATES. XXxl 



The fimple afpcil of the Atlantic Hemifpherc, in the 

 months of January and February, will be fufficient to ren- 

 der intelligible what we have faid refpedling the polar ices, 

 and their periodical efFufions. We fhall treat, in their 

 order, of the fources of the Atlantic, of it's ices, of it's 

 channel, of it's currents, of it's tides, and even of it's dif- 

 charge. 



The Sources of the Atlantic Ocean, are, in Summer, at- 

 the North Pole. They are fituated in the Baltic Sea, the 

 bays of Baffin and Hudfon, at Waigats Strait, &c. It 

 may be remarked on a Globe in relief, that thefe fources, 

 which conflitute the origin of the Atlantic Canal, turn 

 round the Pole in a winding courfe, nearly fimilar to the 

 circuitous current of a river round the mountain from 

 which it defcends ; fo that they colleft, in this part, all the 

 difcharges of the rivers which empty themfelves to the 

 North, and carry their waters along into the Atlantic 

 Ocean. From this arifes a prefumption, that there is, in 

 proportion, much Icfs polar effufion in the part of the 

 •South Seas which is oppofite to it. We ihall farther fee, 

 that Nature has fubjedled to the Atlantic channel the ex- 

 tremities of the two general currents of the Poles, which 

 there terminate, after having made the circuit of the 

 Globe ; and it is by way of oppofition to the fources from 

 which thefe currents ifTue, that I give to the extremities 

 of their courfes the name of mouth. But let us at prefent 

 confine ourfelves to the fubjed: of their fources. 



We conceive that the waters of thefe fources muft flow 

 toward the Line, whither they are carried to replace thofe 

 which the Sun is there every day evaporating ; but they 



have. 



