370 
THE COTTAGE GARDENER. 
August 15. 
Next to the use of pure runniug water in irrigating I 
the sides of hills and elevated table lauds, we have 
treated of the flooding of lower levels with rain-water 
not perfectly pure, but holding a certain amount of 
animal, vegetable, and earthy remains in solution. 
This is, no doubt, advantageous to the growth of plants; 
but tbe effects of the process are not always equally 
favourable to animal life and health, owing to the risk 
of mismanagement. The rich alluvial soils of the great 
historical regions of the world have not always produced 
races of men equally vigorous with their rich vegetation. 
The means used to promote cultivation on their banks 
has not always been accompanied with equal care 
against the slow, unseen, gradual, lowering influences 
of the climate on man himself. And it has been 
accordingly observed, that while the mountain ranges 
of Asia and of Europe have ever preserved a hardy, 
vigorous national race, as old as the hills, no race of 
men has ever preserved itself long in the vallies and on 
the sea coasts; but has had to be constantly renewed 
I by the fresh blood, whether of peaceful settlers or of 
j conquerors. If what has been observed in our own 
time agrees with the concurrent testimony of history— 
if even the natural richness of great rivers cannot be 
turned to agricultural account without some danger— 
I the danger to health must surely be very much in- 
; creased where a fluid highly charged with manuring 
matters is employed. Chemical research goes far to 
account for the supposed unhealthiness of low situations 
by proving, first, that Carburetted Hydrogen exists in 
the air of marshes; and, secondly (according to Pro¬ 
fessor Way), that the clay of alluvial soils is rich in 
ammonia, the result of the decay of a pristine order of 
things. 
But, supposing everybody to be now convinced of the 
danger of using sewerage on the grand scale for pur¬ 
poses of irrigation, is there not yet another chance : 
cannot these products be again brought into a solid, 
portable state, by precipitation from water? Professor 
Way still cautions the agricultural world against buying 
precipitated manures, on account of their very uncertain 
strength and value, and the danger of fraud; and he 
says, that he cannot satisfy himself that any process 
hitherto devised for the purpose can pay. As the actual 
value, in an agricultural point of view, of “that-which- 
has-to-be-carried-out ” is really of importance, we must 
beg, once for all, to offer a few remarks on this part of 
| the subject. 
The principle we have adopted has been used in 
estimating the value of some kinds of fish-manures, and 
is abundantly simple, and tolerably accurate. It consists 
in abstracting entirely from the calculation the water 
held in combination. Well, then, “ that-which-is - 
carried-out” consists daily of about three pounds of 
water, holding in solution three-and a-half per cent of 
valuable salts, and about a quarter-of-a-pound of more 
solid matter, whereof only some twenty-five per cent is 
manure, the remainder being water. Though analysis 
does not prove these ultimate resultants to be quite 
j equal to Guano in fertilising qualities, yet they are 
nearly so. You thus get about what would be equal to 
half-a hundred weight of Guano to each full-grown, 
well-fed person, annually, supposing that there were no 
great loss in collection. But loss in collection there 
must be; and only half of our population are grown 
up, and still less are they all well fed. The calculation, 
therefore, must be at once reduced by at least the half. 
Then the cost of removing a comparatively bulky 
manure must always make farmers prefer Guano ; and, 
again, we have seen that the precipitation from solution 
in a large excess of water is not found to be very 
remunerative. 
We have, in a former paper, alluded to the admirable 
sanitary regulations of the city of Mexico before the 
conquest; to the great waterworks; and to the em¬ 
ployment of 1,000 scavengers daily, in getting out all 
the filth of the city. This would give about a day's 
work in the year for each inhabitant, tbe population of 
the ancient city being more than 300,000; and this 
estimate of a day's wages for each person would be about 
the annual value of the manure; and such a system of 
daily scavenging should support itself nearly. 
On a cottage-farm, or where an allotment adjoins the 
house, of course a very complete system of collection 
may be adopted, and the charge of removal becomes 
nothing. In such a case, nearly the full value of the 
manure may be realised. Therefore is an ample allot¬ 
ment of land not only the best ventilator, by insuring 
sufficient space and isolation, but tbe soil of the garden, 
and the very charred weeds and rubbish—nay, the 
barren subsoil itself, give us at once the best deodo¬ 
risers and disinfectants with which to mix up and 
absorb, to render harmless and turn to profit, all the 
offensive refuse of the house. 
To recur to the calculation with which we set out. 
The vegetable food of each adult person is fairly 
represented by a quarter of Wheat annually, or the 
quarter of the produce of an acre of good land. Half- 
an-hundred weight of Guano for each quarter of Wheat, 
or two hundred weight of Guano to the acre, might be 
a sufficient dressing for the Wheat crop, provided that 
all the straw were consumed along with roots by .cattle, 
and thus a heavy dressing of farm-yard manure pro¬ 
vided to insure a good root-crop in due rotation. 
Powerful liquid and soluble manures—Guano, and 
the like—have the property of bringing into action a 
considerable surplus remaining over in the soil from 
former dressings, the droppings of cattle, &c., not 
brought to account at the time of application, but 
standing to the credit of the farmer in that best of all 
possible saving-bank—the earth— justissima tellus. 
Supposing a meadow to have been duly coated with 
its ten or twelve tons of dung to the acre, chemical 
analysis and practical experience together tell us that a 
much more sparing dose of manuring matter, applied in 
a liquid form, or of Guano, would have given an equally 
abundant crop of Hay ; but, really, the waste is accom¬ 
panied by some saving, and the apparent saving is not 
so great as is at first supposed. On the one hand, our 
land is permanently benefited to some extent by these 
