i8o PHYSICAL SCIENCE BK. iv 



rather than lasting. Winter rain is thin and per- 

 sistent. The fall often occurs in the form of small, 

 fine rain, with an admixture of snow. We call it 

 a snowy day when the cold is intense and the sky 

 leaden. Besides, when the north wind doth blow, 

 producing its characteristic sky, there may be fine 

 rain. With south wind the rain is more persistent, 

 and the drops heavier. 



1 ONE position held by the philosophers of my sect 

 I neither venture to adopt on account of its seeming 

 weakness, nor yet can I pass it by without mention. 

 Where can be the harm of suggesting even an 

 improbable explanation when one has such an 

 indulgent judge ? If we are to apply a test like the 

 pyx to every argument, we shall soon cease to 

 advance any hypothesis at all and be reduced to 

 dumbness. There are very few statements that 

 pass unchallenged. All the rest have to assert 

 their rights before they can win their case. Well, 

 the assertion of the Stoics is, that all the ice-bound 

 region about Scythia and Pontus and the northern 

 quarter is released from its chain in spring ; then the 

 frozen rivers resume their course, then the mountains 

 melt the snows in which they have been buried. 

 It is quite conceivable, therefore, that cool airs arise 

 from this and mingle with the atmosphere of spring. 



2 They add a proof which I have never tested nor 

 have any intention of testing. You, too, I fancy, 

 however anxious you may be to ascertain the truth, 

 will be cautious about making such a trial of snow. 

 The feet are said to suffer less pain when one treads 

 on hard, solid snow than if the snow were slushy 



