M'Keevor's Voyage to Hudson'* Bay, 17 



bly on the surface of a pond, thus making what they call a 

 duck and drake. Agreeing, then, as these two fluids do in 

 so many particulars, what is there, I would ask, in the consti- 

 tution of water that should prevent the transmission of radiant 

 caloric ? Besides, if not transmitted through this fluid, what 

 then becomes of it ? is it converted into slow communicating 

 caloric ? This would be to assert their identity, which, I be- 

 lieve, all philosophers deny. Finally, I may remark, that the 

 entire of this subject, notwithstanding the ingenious and labo- 

 rious experiments of Mr. Lesslie, appears to me involved in a 

 good deal of obscurity. The nature of radiant heat ; whether 

 identical with light or not ; as also the causes, why one por- 

 tion of caloric should escape by radiation, and another by 

 slow communication ; these are points on which, I think, we 

 still stand much in need of further information. Until, there- 

 fore, these matters are more fully investigated, I conceive we 

 have just grounds to conclude, that water and air bear the 

 same relations to radiant caloric. 



Having now enumerated the various causes which I con- 

 ceive to favour the formation of ice on sea-water, I have 

 further to remark, that this opinion is supported by the actual 

 observations of several very intelligent navigators* Mr. 

 M'Nairne, in 1776, shewed that, when Fahrenheit's thermo- 

 ter is at 27| degrees, the fresh particles of sea-water will 

 freeze, and leave nothing but strong brine behind. 



Barentz saw the sea, at Nova Zembla, suddenly frozen over 

 to the depth of several inches. 



Mr. Scoresby, the intelligent navigator already mentioned, 

 tells us, that he has seen ice grow on the surface of the sea to 

 a consistence capable of stopping the progress of a ship with a 

 brisk wind, even when exposed to the waves of the north sea 

 and western ocean. The first layer, or slush ice, as it is 

 termed, being once formed, there is, I conceive, but littte 

 difficulty in accounting for their subsequent enlargement. 

 When the winter season sets in, and that crystallized* snow 

 begins to fall, it becomes consolidated by the excessive cold 

 of the climate, and will, of course, press down the primary 

 strata, to use a geological phrase. The other aqueous me- 

 teors of hail, rain, &c. suffering a similar condensation, we 

 can readily conceive, that, by a gradual accumulation in this 



* That snow is deposited on the ice in high northern latitudes must be al- 

 lowed, because no field has yet been met with which did not support a con- 

 siderable burthen of it. S!e Scoresby on Polar lee. Wernerian Transac- 

 tions. 



VOYAGES and TRAVELS. No. 2. Vol. H. D 



