152 



Liquid Manure. 



only varies at different seasons of the year, but a considerable pro- 

 portion of the merely mechanically suspended matters invariably 

 subsides when the specimen water is suffered to rest, so that the 

 chemical analysis is in fact merely that of those portions in chemi- 

 cal combination : to e:ive an instance of this, Thames water usually 

 contains from 1 to 2 per cent, of mechanically suspended matters ; 

 yet, when this water was analysed by Dr. Bostock, 10,000 parts 

 were found to contain only about If parts, namely. 



Organic matters 0' 07 parts 



Carbonate of lime (chalk) 1*53 „ 



Sulphate of lime (gypsum) 0*15 



Muriate of soda (common salt) .... 0 • 02 „ 



And in the same quantity of the water of the Clyde, Dr. Thomson 

 found only a little less than li part, namely. 



Common salt 0*369 parts 



Muriate of magnesia 0 ' 305 „ 



Sulphate of soda (Glauber salt) . . . 0*114 „ 



Carbonate of lime (chalk) ..... 0*394 „ 



Silica (flint- earth) 0*118 „ 



There is no stream more celebrated for its prolific water-mea- 

 dows than the Itchen, in Hampshire ; and in no part of England 

 is the system of irrigation better understood and more zealously 

 followecl. I have several times examined the water of this river, 

 taken from above the city of Winchester : it contains in 10,000 

 parts, after all its mechanically suspended matters have subsided, 

 about 2|- parts, namel}^. 



Organic matter 0.02 parts 



Carbonate of lime (chalk) 1 • 89 „ 



Sulphate of lime (gypsum) 0*72 „ 



Muriate of soda (common salt) ... 0*01 „ 



The water of lakes is usually still more surcharged with foreign 

 substances than those of rivers ; and from the use of such waters, 

 especially if an occasional or winter stream of water passes through 

 them, I have witnessed great fertilizing effects produced on mea- 

 dow-land. 



In my conclusions with regard to the theory of irrigation, I 

 have found many able practical farmers concur. Thus, Mr. 

 Simmonds, of St. Croix, near Winchester, considers that the great 

 benefit of v/inter-flooding for meadows is derived, in the first 

 place, from the deposits made by the muddy waters on the grass ; 

 and, secondly, from the water covering the grass, and preventing 

 the ill effects arising in the winter from the sudden transitions in 

 the temperature of the atmosphere. This gentleman is perfectly 



