18 J. MILNE ON THE SINAITIC PENINSULA AND N.W. AEABIA. 



will be seen rolling along over each other ; and on putting the ear 

 near to these a slight rustling noise may often be detected. 



By taking a flat piece of wood and using it as a straight-edge, I 

 made several practical^ level patches of ground, on which I was 

 enabled to see the action of the drift in the formation of ridges. 

 Although when standing up no movement in the sand could be 

 detected, yet on stooping down I perceived that ridges were being 

 formed, not simultaneously over the whole surface, but commencing 

 to windward. The crest of each of these small undulations appeared 

 to be invariably covered with the redder particles of sand, whilst the 

 yellow ones were left in the hollows. 



In the case of larger ridges, which were about 6 inches in height, 

 their crests were composed of the larger particles, which, as far as 

 colour was concerned, could not be distinguished from those forming 

 the hollows. Small movements of this description are constantly 

 going on ; but in a gale, judging from experience, the results 

 must be considerably greater. When a moderately heavy wind 

 is blowing, it is almost impossible to face the " blast." On your 

 hands a tingling sensation is felt ; and on lowering them towards 

 the ground this rapidly and irregularly increases in power until 

 they are within a foot of the ground, when it becomes unbearable, 

 the feeling produced being not unlike that occasioned by drawing 

 off the keeper of an electro-magnetic machine. 



Another and more important action of the sand-drift is the 

 cutting of the surface of all stones which are exposed upon the desert 

 — a fact which has often before been noticed, and may be well exem- 

 plified by the Sphinx near Cairo, and two faces of Cleopatra's 

 Needle at Alexandria. Portions which are buried, or otherwise 

 protected, are not cut, the consequence being that almost every stone, 

 when picked up, presents two surfaces which differ in appearance, 

 one being uneven and rough, whilst the other is pitted and polished. 

 In the district especially referred to, near Nackhl, where the 

 stones scattered in the desert are chiefly limestone, the definite 

 character given to them by this sand is such that it could not 

 be seen without being remarked. All have a peculiar polish, 

 looking as if they had been smeared with grease, a lustre nearly 

 represented in the fractured surface of some specimens of witherite. 



In addition to this, they are all, more or less, pitted with small cup- 

 shaped hollows, which apparently indicate the softer portions of the 

 stone. Some few have cut upon their surfaces curious worm-shaped 

 furrows ; whilst others have exhibited such differences in hard- 

 ness that their softer portions have been so far cut into and carried 

 away that the remainder is as ragged in its outline as the root of a 

 tree, for which in many instances they might readily be mistaken. 



Should these stones hereafter become completely buried, as many 

 already are, future investigators will find in them marks as clearly 

 indicative of their origin as the rounded forms of waterworn 

 pebbles or the angular and scratched faces in beds of glacial drift. 

 Just as we infer from the latter the existence of former glaciers, so 

 will they infer the former presence of deserts and sand-drifts. 



