182 TRANSACTIONS OF THE [may 13, 
JEBEL NAGOUS AND A NEW MOUNTAIN OF THE BELL. 
I have just returned from a journey of four weeks in the 
Desert of Mount Sinai, made with the especial object of study- 
ing the Jebel Nagous in connection with the joint researches of 
Dr. Alexis A. Julien and myself on Musical Sand. The ‘* Moun- 
tain of the Bell ” is situated on the Gulf of Suez, about four and 
a half hours from Tor by the roundabout camel route. It was 
first described by Seetzen in 1808, since which time it has been 
visited by Ehrenberg, Gray, Wellstedt, Riippell, Ward, New- 
bold, Capt. H. 8. Palmer, and the late Professor Palmer, as well 
as by large numbers of pilgrims. My observations confirm their 
accounts of the acoustic phenomena heard, but my measure- 
ments differ widely from those of all the travellers, save perhaps 
Professor Palmer. 
The name Jebel Nagous is given by the Bedouins to a moun- 
tain nearly:three miles long and about 1,200 feet high, composed 
of white sandstone bearing quartz pebbles and veins. On the 
western and northern side are several large banks of blown sand 
inclined at high angles. The sand onone of these slopes, at the 
N.W. end of the mountain, has the property of yielding a deep 
resonance when it slides down the incline either from the force 
of the wind or by the action of man. This bank of sand I dis- 
tinguish from the others by calling it the Bell Slope. It is tri- 
angular in shape and measures 260 feet across the base, 5 to 8 feet 
across the top, and is 394 feet long (high). It has the high in- 
clination of 31° quite uniformly. It is bounded by vertical cliffs 
of sandstone and is broken towards the base by projecting rocks 
of the same material. The sand is yellowish in color, very fine, - 
and possesses at this inclination a curious mobility which causes 
it to flow, when disturbed, like treacle or pitch, the depression 
formed being filled in from above and advancing upward at the 
same time. ‘The sand has none of the characteristics of sonor- 
ous sand found on beaches. When pulled downward by the 
hands, or pushed by the feet, a strong vibration is felt and a low 
note is plainly heard, resembling the deep bass of an organ-pipe. 
The loudness and continuity of the note are related to the mass 
of sand moved, but I think that those who compare it to distant 
thunder exaggerate. The bordering rocky walls give a marked 
echo, which may have the effect of magnifying and prolonging 
the sounds, but which, as I afterwards demonstrated, is not 
essential. There are no cavities for the sand to fall into, as 
erroneously reported. The peak of Jebel Nagous rises above the 
Bell Slope to the height of 955 feet above the sea level, as deter- 
mined by a sensitive aneroid. 
After studying the locality and phenomenon for several days, 
