58 DISCUSSIONS IN CLIMATOLOGY. 



but when the temperature of the water is near the 

 freezing-point, snow will be the result. A diminution, 

 for example, in the heat brought by the Gulf Stream 

 that would very greatly lower the surface-temperature 

 of the sea surrounding Great Britain would, he says, 

 bring about a heavy snowfall, and lead to permanent 

 snow and ice. Again, he maintains, " As there is no 

 reason to suppose that the surface-temperature of the 

 sea would be lower during winter in aphelion and high 

 eccentricity, it follows that there will not be more 

 snow than now in countries where rain is the rule, 

 even in winter, all other things equal." 



There is surely a fallacy lurking under this theory 

 of M. Woeikof. Snow instead of rain is not, as he 

 supposes, owing to the low temperature of the water 

 from which the vapour is derived, but to the low tem- 

 perature of the air where the vapour is precipitated. 

 Of course, when the surface of the sea is near the 

 freezing-point, the air over the sea and the adjoining 

 land is usually also not far from the freezing-point, 

 and consequently the precipitation is more likely to 

 be snow than rain. If the air be cold, as it generally 

 is over a snow- and ice-covered country, a high tem- 

 perature of the adjoining seas, were this possible, 

 would greatly increase the snowfall, because it would 

 greatly augment the quantity of vapour which would 

 be available for snow. 



