CALCAREOUS MANURES-APPENDIX. £8 1 



proaches very close to it, and the narrow strip of fertile and irrigated land 

 between must necessarily have been deeply though gradually covered by 

 the same calcareous sand ; (indeed the continued operation of the like 

 causes is raising, not only the borders, but even the bed of the Nile ;) yet 

 Denon mentions particularly the high state of cultivation seen in his next 

 day's journey up the river. ' It is well known that wherever the waters of 

 the Nile have been conveyed to irrigate these sands, an astonishing degree 

 of fertility has been the immediate consequence ; and that wherever the 

 canals for this purpose have been permitted to become dry, (often the effect 

 of political causes on this wretched population,) there is as sure a return to 

 the former state of naked and barren sand. There is reason also to be- 

 lieve (though upon slighter foundation,) that portions of the great deserts of 

 both Asia and Africa also are excessively calcareous, and owe their ste- 

 rility to that cause, combined with the general absence of water. The only 

 direct testimony as to this character of the soil, is in the following passage 

 from Madden's Travels. He was in the desert between Egypt and Judea. 

 " Next day we travelled all day long without seeing a single tree, or the 



smallest patch of verdure, or laying our eyes on any human being." 



"The soil was no longer sandy, but of a hard gravel, on which a carriage 

 might be rolled from Salehie to Suez. At night we stopped at a well with- 

 out water, and here I examined the soil, three feet below the surface ; [for] 

 two feet deep there is a superficial stratum of calcareous pebbles, and 

 below that, a solid bed of limestone, which I believe to be the basis of the 

 soil of all Egypt."-[p. 122, vol. ii.. Am. Ed.] 



" One thing is certain that wherever there is water, no matter in what 

 part of the wilderness, there vegetation is to be found. The stopping up 

 of the canals, and the want of irrigation, are the great causes of desolation 

 which favor the extension of the desert. The country from San to Salehie, 

 and probably to Suez, was formerly a cultivated country : the ruins of 

 palaces, such as those of Zoan and that of Beit Pharoon, now in the middle 

 of the desert, prove that the country around then must have been cultivated, 

 and that at a very short period before our era." — lb. p. 1 26. 



Lieut. Burnes, who has recently published the very interesting account of 

 his travels across central Asia, after describing, in various detached passages, 

 the barren and often naked sands of the great Tartarian desert, over which he 

 had been many weeks passing, and of the great scarcity of water even in the 

 few wells, and the total want of it elsewhere, thus describes the approach to 

 the river Moorghab, or Merve, and the effects of irrigation. "By the time the 

 sun had set, we found ourselves among the ruins of forts and villages, now 

 deserted, which rose in castellated groups over an extensive plain. I have 

 observed that we were gradually emerging from the sand-hills, and these 

 marks of human industry which we had now approached, were the ancient 

 remnants of civilization of the famous kingdom of Merve, or Meroo. Be- 

 fore we had approached them, we had not wanted signs of our being de- 

 livered from the ocean of sand, since several flocks of birds had passed 

 over us. As the mariner is assured by such indications that he nears land, 

 we had the satisfaction of knowing that we were approaching water, after a 

 journey of 1 50 miles [from the last habitable spot] through a sterile waste, 



where we had suffered considerable inconvenience from the want of it." 



" This river was formerly dammed above Merve, which turned the principal 

 part of its waters to that neighborhood, and raised that city to the state of 

 richness and opulence it once enjoyed. The dam was thrown down about 

 45 years ago by Shah Moorad, a king of Bokhara, and the river now only 

 irrigates the country in its immediate vicinity. The inhabitants cultivate by 

 irrigation, and every thing grows in rich luxuriance" and where the 



