SNOW-WAVES AND SNOW-RIPPLES 97 



to windward, and thus giving a sudden and swift 

 but momentary motion up -wind. A similar effect 

 was sometimes produced during moments of heavier 

 snowfall . 



On Arthur's Seat, near Edinburgh, on the Pent- 

 land Hills, and near Grantown-on-Spey I observed 

 the action of wind upon a snow surface when there 

 was no snowfall. The first case which I will de- 

 scribe was during the removal of the surface layers 

 of a recent snowfall where the material was light 

 and loose. The surface was beautifully covered 

 with ripples having wave-lengths of from 3 to i 5 

 inches, with their cliffs facing up -wind. The cliffs, 

 though broadly extended, were sinuous, none being 

 straight for more than a few inches. The con- 

 centration of the wind in the re-entrant angles or 

 notches threatened to cut through the ridges and 

 thus destroy by erosion the transverse, or rippled, 

 form, but the drifted particles which were con- 

 centrated here were sufficiently adhesive to mend 

 the threatened breaches. The salient angles, too, 

 tended to become more prominent, and thus destroy 

 the transverse arrangement, but they were under- 

 cut by the wind, and the overhanging cornices 

 receded by collapse, so that the transverse arrange- 

 ment was preserved. 



But the rippled, or transverse, arrangement of 



