298 JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. l September 28, iss*. 
attack of these caterpillars as lambs in a foldyard from the fox outside the 
enclosure. 
“ The amount of attack of this moth depends very much on the weather. If 
the ground is frozen hard in November it is manifest it cannot come up through 
it; also much rain when the caterpillars are moulting is bad for them, and also 
such wet weather as will thoroughly soak the ground in which the chrysalids 
lie will destroy them. 
" Yours truly, Eleanor A. Ormerod, 
“ Consulting Entomologist of the Royal Agricultural Society.” 
Let us hope, then, that the large amount of rain we had before 
the caterpillars came to maturity will have destroyed a great 
many of these troublesome creatures. It is marvellous to see the 
way in which the trees, which up to near the middle of July were 
“ as bare as in midwinter,” have recovered as to foliage ; but the 
growth is still very soft, and I am afraid the frosts which we are 
already experiencing will prevent it ripening fully.—W. Taylor. 
THE CHEMISTRY OF MANURES. 
I willingly reply to the questions put to me by “Inquirer” 
—though he will permit me to observe that the first of them, 
“ Is it the intention of ‘ J. B. K.’ to affirm that a good garden 
soil eau be enriched in nitrogen or potash, or phosphoric acid, 
or any other constituent of plant life, by admixture with a 
manure which is more deficient in these elements than itself ? ”— 
hardly expresses any practical question arising out of the dis¬ 
cussion. What actually occurred was, that Mr. Taylor spread on 
the surface of a border which had been exhausted by the pro¬ 
duction of probably 8 or 10 lbs of fruit, wood, and leaves per 
square yard, a dressing of about 1 inch thick, or some 50 or 60 lbs. 
per square yard, of soil which has been enriched with a quantity 
of solid excreta and a portion of liquid excreta equal to that 
which one individual would supply during a week ; for this is 
about the quantity indicated by Mr. Taylor’s statement, that he 
obtains the earth which has been used by fourteen persons during 
six months, and that this (as I understand) is sufficient for only 
half his border, or for an extent of 360 square yards. Now, what 
is the nature of the addition thus made ? Assuming excreta of 
average quantity and composition, and that one-sixth of the daily 
urine voided is included, these 360 yards will receive annually (in 
addition to whatever value there may be in the earth itself, or the 
burnt clay employed in the closets), the following ingredients 
in pounds:— 
Supplied to border. Rate per acre. 
Nitrogen. 
18 
, , 
260 
Potash. 
42 
# . 
60 
Pho-phoric Acid 
87 
. , 
120 
Lime . 
3 
43 
Magnesia . 
. .. 2 6 
, , 
37 
Oxide of Iron. 
10 
Sulphuric Acid. 
06 
• . 
9 
Chlorine. 
• • 
95 
This would be very nearly equivalent to a dressing at the rate 
of 30 cwt. of good guano per acre, or two-thirds of a pound per 
square yard, and such an application is obviously a very rich 
diess rg. But while in the concentrated form of guano it can bear 
the cost of transport from Peru, if it were diluted with one hundred 
times its weight of common earth, which is its form when obtained 
from eait'a closets, it would not pay for its transport from the 
next parish. This is in fact the whole difference between guano 
and earth-closet manure. When circumstances permit the latter 
to be obtained without any charge for carriage it is as good as 
guano, provided enough of it be used ; and Mr. Taylor is able to 
use, and does use, enough. 
The second question—“ Does ‘ J. B. K.’ consider that earth- 
closet manure is really superior to that prepared by Messrs. 
Arnold & Co., for instance, for manuring Vines ? ” is virtually 
answered by what I have already said. The one is diluted and 
weak, the other is concentrated and strong; but if a pound of 
the earth is obtained at less cost on the spot than one-eighth of an 
ounce of the artificial manure, then it is the cheaper of the two. 
Whether it is the better depends entirely on how it is used. For 
a single application, to last through the season, earth-closet 
manure in adequate quantity is undoubtedly the better ; but 
artificial manures have one advantage in the fact that they can 
be varied so as to supply the special demands of the plant at 
different seasons. Aware of this, Messrs. Arnold supply different 
preparations for use in spring, summer, and winter ; the first 
containing, I believe, more nitrogen to support the earliest growth 
of leaves and wood, the second more potash to swell and firm 
the berries and ripen the wood, the third more phosphoric acid 
to encourage the growth of roots. In like manner the best 
farmers use both farmyard dung for the mainstay of their crops, 
and add during their growth special dressings of soluble forms 
of nitrogen, potash, phosphoric acid, or magnesia as may be 
required by the special crop ; and when a gardener can do the 
same he will probably find some benefit in it. In my own case, 
having no earth-closet manure, but having the advantage of a 
farm in which much cake is consumed by cattle under cover, I 
profit by the fact by giviug the Vines in early summer a mulching 
of straw manure, both to keep the soil moist and to enrich the 
waterings ; but I precede this with some waterings in which the 
urine of the cattle is administered, and these again are preceded 
by waterings in which artificial manures are dissolved, so as to 
supply the roots when they first start into growth with all that 
they require at the time of greatest pressure. No doubt if I had 
only one of these resources I could so arrange as to make it suffice. 
So Mr. Taylor, having an excellent manure of what may be called 
a universal character, makes it answer with the help of lime to 
quicken its decomposition and make it most soluble in early 
spiring, while with copious waterings he washes out any super¬ 
fluity. It was to gardeners who have not any of these resources 
that I recommended the artificial manures compounded for them 
at reasonable rates by a competent and respectable firm. I do 
not call them better than natural manures, but administered with 
due care they will act as well, and often they will be found a most 
serviceable addition. 
The accidental delay of a week enables me now to advert to the 
letter of Mr. Boyle in the last number of the Journal. Iu the first 
place, the fact of his being a vegetarian does not of itself make 
the earth-closet manure less rich. The human body must have a 
certain supply of nitrogen and minerals whether derived from 
animal or vegetable food. Many vegetables contain as much (or, 
as Sir John Lawes has shown, often more) nitiogen than there is 
in meat with its usual proportion of fat; and a vegetarian, there¬ 
fore, probably consumes and excretes as much as a flesh-eater, 
possibly even more in a solid form, fur the solid excreta contain 
the undigested portion of the food, and a smaller proportion is 
digested of vegetable than of animal food. But, secondly, in all 
cases of the use of earth-closet manure there is a doubt, which only 
analysis can solve, how much virtue is in the earth itself before its 
use. Thus, for instance, Dr. Voelcker found that the earth em¬ 
ployed in the Wakefield Prison had itself the composition of a 
“rich garden mould,” and if we put the commercial value on the 
ingredients he found in it we shall find it would be valued as 
manure at 7 s. 7d. per ton. Add to this 3 s. or 4#. additional value after 
its use (supposing it employed in a private family instead of a 
prison) and we have say 11.?. per ton as its true commercial value, 
which is double the ordinary price of farmyard manure. But even 
supposing the original earth used by Mr. Boyle, Mr. Taylor, or 
others is not so rich as this, we may observe that Mr. Boyle says 
it is “ bulk for bulk worth double the amount of dung.” But earth 
is greatly heavier than farmyard dung as it is loaded into a cart 
or barrow, probably quite twice as heavy, and therefore “ bulk for 
bulk ” would give twice the real quantity by weight of earth as of 
dung on an equal space of ground. But finally, and this is perhaps 
most important of all, the earth-closet manure contains all its in¬ 
gredients in a state of complete disintegration, and thus ready for 
immediate decomposition and use by the plants, while farmy r ard 
dung is lumpy, wet, and consequently very slow in its action. 
The virtues of the former will be given out to one crop (as Mr. 
Taylor illustrates, for he gives his heavy dressing annually), while 
of slung the effect does not half appear in the first crop ; it partly 
accumulates in the soil, and partly is lost in winter washings. 
This fact is probably a main reason why earth-closet manure shows 
on all crops to such immediate advantage, and if dressings are 
given of twice the weight of the dung with which it is compared 
there is no wonder it seems greatly superior, as in fact for one crop 
it is.—J. B. K. _ 
Cows and horses are all strict vegetarians, and it is not sug¬ 
gested lhat farmyard dung is not so good as if the stock were fed 
on animal food. How, then, does Mr. Boyle make out that his 
vegetarian diet detracts from the fertilising qualities of his earth- 
closet manure? No doubt Dr. Yoelcker’s opinion is entitled to 
much respect; but everybody who has used earth-closet manure 
can testify to its value as a powerful fertiliser. The great pity is 
that so much valuable manure is allowed to pollute our rivers and 
poison our streams through the length and breadth of the land.— 
Peter Ferguson, Monk Wearmouth. 
In a general sense, the manure most suitable for any given soil 
to increase its fertility is that which contains those constituents 
in which the soil is most deficient. The illustrious Liebig has 
enunciated what he calls a law of minimum, which he expresses 
as follows :—“ Every field contains a maximum of one or several, 
and a minimum of one or several nutritive substances. It is by 
the minimum that the crops are governed, be it lime, potash, 
nitrogen, phosphoric acid, magnesia, or any other constituent.” 
