Tour in England* 
t <£ In an equal quantity ot the waters of the 
Clyde, Dr. Thomson found 1 1-6 part of solid 
substances, namely,— 
Parts. 
Common salt, 
0.369 
Muriate of Magnesia, 
0.305 
Sulphate of Soda, 
0.114 
Carbonate of lime, 
0.394 
Silica, 
0.118 
“ The water of the Itchen 
in Hampshire 
is one of the most celebrated of all the 
southern streams, for the use of the irrigator. 
I found in 10,000 parts of its water, about 
2 1-2 parts of solid matter, viz 
:— 
Parts. 
Organic matter, 
0.02 
Carbonate of lime, 
1.89 
Sulphate of lime, 
0.72 
Muriate of soda, 
0.01 
“ From an examination of the substances 
found in these streams, (and they afford a 
pretty correct view of the contents of most 
others,) the farmer will see that they all yield 
ingredients which are the food or natural 
constituents of the grasses. TJius, sulphate 
and carbonate of lime are found in most of 
them, and there is no river-water which does 
not contain, in some proportion or other, or¬ 
ganic matter. 
“ If the river-water contains gypsum (sul¬ 
phate of lime) which it certainly does—if the 
water is hard , it must, under ordinary cir¬ 
cumstances, on this account alone be highly 
fertilising to meadows, since all grasses con¬ 
tain this salt in very sensible proportions ; 
for, calculating that one part of sulphate of 
lime is contained in every two thousand parts 
of river water, and that every square yard of 
dry meadow soil absorbs only eight gallons 
of water, and this is a very moderate allow¬ 
ance, formally soils will absorb three or four 
times that quantity, then it will be found that, 
by every flooding, more than one hundred 
weight and a half of gypsum per acre is diffus¬ 
ed through the soil in the water, a quantity 
equal to that generally adopted by those who 
spread gypsum on their clover crops, lucern, 
and sainfoin, as a manure, either in the state 
of powder, or as it exists in ashes. And if 
we apply the same calculation to the organic 
substances, ever more or less contained in 
flood waters, and allow only twenty parts of 
animal and vegetable remains to be present 
in a thousand parts of river water, then we 
shall And, taking the same data, that every 
soaking with such water will add to the 
meadow nearly two tons per acre of animal 
and vegetable matters, which, allowing in 
the case of water meadows, five floodings 
per annum, is equal to a yearly application of 
ten tons of organic matter. 
“ The quantity of foreign substance present 
in river-water, although commonly less, yet. 
very often exceeds, what I have thus calcu¬ 
lated to exist in it. I have found it impossi¬ 
ble, however, to give from analysis the 
amount which, under ordinary circumstances, 
is present in river waters, with any tolerable 
accuracy, since the proportion not only va¬ 
ries at different seasons of the year, but a 
considerable proportion of the merely me¬ 
chanically suspended matters subside, when 
the specimen water is suffered to rest. In 
my conclusions in regard to the theory of 
irrigation I have found many excellent prac¬ 
tical farmers concur. Thus Mr. Simmons of 
St. Croix, near Winchester, considered that 
the great benefit of water flooding for mead 
ows is derived, in the first place, from the 
deposites made by the muddy waters on the 
grass ; and, secondly, from the winter cover¬ 
ing with water preventing the ill effects to 
the grass of sudden transitions in the tem¬ 
perature of the atmosphere. This gentleman 
is perfectly aware of the value of the addition 
of the city drainage of Winchester to the fer¬ 
tilising qualities of the Itchen river water, 
and of its superiority for irrigation after it 
has flowed past the city, having water mead¬ 
ows both above and below the town; and he 
finds that, if the water has been once used 
for irrigation, that then its fertilising proper¬ 
ties are so materially reduced, that it is of 
little value for again passing over the 
meadows.” 
Sir Humphrey Davy thus explains the fer¬ 
tilising effects of irrigation:—“ In general, in 
nature, the operation of water is to bring 
earthy substances into an extreme state of 
division : but in the artificial watering of 
meadows, the beneficial effects depend upon 
many different causes, some chimical, some 
mechanical. Water is absolutely essential 
to vegetation; and when land has been 
covered by water in the winter, or in the be¬ 
ginning of spring, the moisture which has 
penetrated deep into the soil, and even the 
subsoil becomes a source of nourishment to 
the roots of the plants in the summer, and 
prevents those bad effects which often hap¬ 
pen in lands in their natural state, from a 
long continuance of dry weather. When the 
water used in irrigation has flowed over a 
calcarious country, it is generally found im¬ 
pregnated with carbonate of lime; and in 
this state it tends, in many instances, to ame¬ 
liorate the soil. Common river-water also 
generally contains a certain portion of or- 
