186 VISIT TO THE PYRAMID OF CHEOPS. 



we had the good fortune to observe on its apex an 

 interesting physical phenomenon, of which I subse- 

 quently gave an account in PoggendorfF s Annalen 

 under the title, "Description of unusually strong elec- 

 trical phenomena on the Cheops Pyramid near Cairo 

 during the blowing of the Chamsin." 



During our donkey ride from Cairo to the pyramid 

 there arose an unusually cold desert wind, which was 

 accompanied by a peculiar ruddy colour of the horizon. 

 During our ascent or rather our transport by the Arabs, 

 who always encamp by the Gizeh pyramids, and do 

 not allow the office to be taken from them of carry- 

 ing or rather throwing the visitors up the steps, each 

 a yard high, the wind assumed a tempest-like force, 

 so that it was to a certain extent difficult to keep 

 oneself upright on the flattened apex of the pyramid. 

 The raised desert dust had now become so thick that 

 it appeared like a white mist, and altogether obscured 

 the view of the ground. It gradually rose higher and 

 higher, and after some time wrapped even the summit 

 on which I with my ten engineers was standing. Then 

 a remarkable hissing noise was heard, which could not 

 have been caused by the wind itself. One of the 

 Arabs called my attention to the fact that by raising 

 his outstretched finger above his head a sharp singing 

 sound arose, which ceased as soon as he lowered his 

 hand. I found this confirmed when I myself raised a 

 finger above my head; at the same time I noticed a 

 prickling sensation in my finger. That we had to do 

 with an electrical phenomenon appeared from the 



