68 MR. C. BAILEY ON THE STRUCTURE ETC. 



of rice in Egypt^ and shows that the water used for the 

 young plants is drawn from the Nile by fixed machines 

 during the principal part of the year; but in times of 

 inundation^ during the rising of the river^ the water is 

 naturally distributed^ its particular course being regulated 

 by the embankments which protect the fields. He states 

 that the Naias graminea grows in the canals of the rice- 

 fields at Kosetta and in the Delta, but he considered it 

 only a variety of Naias fragilis, which grows in the same 

 waters. 



The irrigation of modern Egyptian cotton-plantations 

 will be effected by much the same means, the Nile, with 

 its artificial ramifications, being the chief water-supply of 

 the country. Fruits of the Naias may reach Egypt from 

 Abyssinia, or from the great lakes of Equatorial Africa; 

 the Nile water supplied to the growing cotton-plant will 

 be accompanied by these fraits, some of which would be 

 left dry upon the surface after the water had percolated 

 through the upper soil, but they would not germinate there. 

 Either by the agency of the wind, or through accidental 

 contact with the soil, they become mixed with the cotton 

 exported to England. When the bales of cotton reach the 

 Lancashire mills, the fruits of the Naias would be removed 

 in the blowing-room, or by the carding-engines. The 

 refuse is turned out of the mill into the yard, whence the 

 wind and other agencies transport the fruits into the tepid 

 water of the canal ; here they meet with a suitable nidus 

 for germination and growth, and the result is the appear- 

 ance of an alien in our flora. 



If these surmises have any substratum of truth, the 

 Naias may occur in any mill-pond connected with works 

 where Egyptian cotton is used, and where the water is 

 raised to a permanently high temperature by the conden- 

 sation of steam from the boiler. As Egyptian cotton is 



