26 Memoir on the Aden Eeservoirs. [no. S, new series, 
ed into canals for the irrigation of the fields and gardens of Mareb, 
and by means of which, that city became what Pliny styled it, " the 
mistress of cities, and the diadem on the brow of the universe." 
The dyke having somewhat sufifered from the lapse of time, was 
repaired and consolidated by the Himyarite Queen Balkis, about 
the commencement of the Christian Era, and in her time it was 
deemed too strong' ever to be destroyed. 
That catastrophe did however at length take place, the dam which 
had stood for 1700 years, yielded to the pressure of water from 
within, and gave way, deluging the country far ana wide, and car- 
rying away the whole city with the neighbouring towns and people ; 
and thus the prosperity of Mareb was destroyed. 
This event took place about A. D. 120, and is famous in Arabi- 
an History as the " Sail-el-ArinC^ or " rush of water from there' 
servoir'^ by which name it is mentioned in the Koran. 
M. Arnaud, a French traveller, reached Mareb in 1843 after a 
difficult and arduous journey, and succeeded in obtaining measure- 
ments for a plan of this famous dyke, which I believe he has since 
published ; according to his account, it was situated between two 
hills named Balak, which, when joined, by the wall, formed the re- 
servoir ; the enclosed space is of such extent, that a shout from'one 
end, could not be heard from the other, and the massive masonry, 
though rent here and there, still attests the original solidity of the 
work. 
This doubtless suggested similar reservoirs in other parts of 
Arabia and the neighbouring coasts of Africa, which have usually 
been subject to it, and with the spread of the Kaliphate West- 
wards, the idea was introduced into Spain and other Mahomedan 
conquests. 
The Reverend Mr. Stern, who succeeded in reaching Sanaa in 
September ^of this year, (1856) informed me that, duringjthe whole 
of the route between that city and Menakhir, near Jebel Harraz, 
large and beautifully constructed cisterns occur, these during his 
visit were perfectly water-tight and contained a considerable supply 
of water, though partly filled up and choked with long rank grass. 
