712 



River Welland with the Soar and (through the Soar) with the Trent. 

 When, therefore, it was found in the Lene, near Nottingham, it should 

 be remembered that it was in apart of the same water-system. After- 

 wards it was found in the locks at Welford and Watford, near North- 

 ampton ; but these points are within a very short distance of each 

 other, and both are on the same line of canal as the Foxton Reservoir. 

 In 1849 it was found in the canal near Burton-on-Trent, and in the 

 Trent River ; but these points, although in two new counties, were all 

 in water communication with the previous stations ; and, again, when 

 it was found in Warwickshire, near Rugby, and in the Oxford Canal, 

 these are within ten or twelve miles of the Watford Station, and on 

 the same line of canal. These several midland localities may therefore 

 be regarded virtually as but one, because the Anacharis, when once 

 introduced, would in a few years inoculate any connected water-sys- 

 tem, from one end to the other. 



Indeed, if any one will take the trouble to look at a good map of 

 England, it will appear clear that there was hardly^ a spot so well- 

 calculated as a centre from which to inoculate our English rivers, as 

 Rugby or the Watford Locks, near the Crick Railway Station. From 

 such a point, situate at an altitude above the sea of about 350 feet, 

 and very nearly at the line of water-shed which divides England into 

 the river-basins of the Severn on the west, the Trent on the north, 

 the Ouse on the east, and the Thames on the south, a few detached 

 sprigs, travelling different ways, would enter the Severn through the 

 Avon vid Rugby and Warwick ; the Thames through the Cherwell at 

 Banbury, and thence by Oxford ; the Nene above Northampton ; the 

 Ouse at Buckingham; the Welland at Market Harborough ; the Trent 

 above Burton, by the Anker and Tame ; and, again, lower down, at 

 Nottingham, by the Soar ; and from Nottingham the Witham could 

 be reached by the Grantham Canal ; and thence by Lincoln the drains 

 of North Lincolnshire would be impregnated. And then, when the 

 pest had travelled as far down (on the Trent, for example) as the top 

 of the Humber, the numerous vessels ascending the great valley, of 

 4000 square miles, drained by the Yorkshire Ouse, would carry it up 

 with them, and so inoculate that ample river and its numerous tribu- 

 taries. 



That the plant is only now descending these rivers is evident. It 

 has appeared in the upper part of the Ouse, and for four years has 

 been observed in the Nene ; two years ago it appeared at Lincoln, but 

 had not then reached the northern parts of that county ; and in our 

 own river, while it occupies the line of descent from Cambridge to 



