182 
THE CULTIVATOR. 
course for the purpose to a regular scientific chemist, the object may 
be attained by application to any intelligent apothecary, by furnish¬ 
ing him with the following account of the modes of procedure :— 
The ingredient of marls, on which their fitness for agricultural 
purposes depends, is the carbonate of lime. It is owing to the pre¬ 
sence of this earth that marls effervesce on the addition of acids, 
which is one of their distinguishingcharacters : to ascertain which— 
‘ Let the marl be put into a glass partly filled with water, which 
will expel a portion of air contained mechanically in the marl, and 
thus obviate one source of fallacy. When the marl is thoroughly 
penetrated by the water, add a little muriatic acid, or spirit of salt. 
If a discharge of air should ensue, the marly nature of the earth will 
be sufficiently established.’ 
Then, to find their composition— 
‘Pour a few ounces of diluted muriatic acid into a Florence flask, 
place them in a scale, and let them be balanced. Then reduce a few 
ounces of dried marl into powder, and let this powder be carefully 
and gradually thrown into the flask, until, after repeated additions, 
no further effervescence is perceived. Let the remainder of the 
powdered mar) be weighed, by which the quantity projected will be 
known. Let the balance be then restored. The difference of 
weight between the quantity projected, and that requisite to restore 
the balance, will show the weight of the air lost during the efferves¬ 
cence, and will stand thus,— 
‘If the loss amount to thirteen per cent of the quantity of marl pro¬ 
jected, or from thirteen to thirty-two per cent, the marl assayed is 
calcareous marl, or rich calcareous earth. 
‘ Clayey marls, or those in which the argillaceous ingredient pre¬ 
vails, lose only eight to ten per cent of their weight by this treatment; 
and sandy marls about the same proportion. The presence of much 
argillaceous earth may be judged by drying the marl, after being 
washed with spirit of salt, when it will harden, and form a brick.’ 
ON POTATOES.—( Concluded from page 168.) 
PLANTING. 
We must further remark, that, whether planted whole or in sets, 
the roots should not be taken up, when intended for that purpose, 
before th? haulm is withered ; so as to allow the roots to reach a 
state of perfect maturity. 
“ The potato lying in the ground during the winter becomes per¬ 
fectly matured, retains its juices, is preserved from fermentation, and 
germinates at the natural season; and we have found that the plant 
proceeding from it is luxuriant and healthy. Under our treatment 
the tuber is taken up immature ; it has, therefore, a greater tenden¬ 
cy to fermentation, from its juices being more crude. It is heaped 
up in large quantities, in close houses or pits, and these large heaps 
increase the tendency to fermentation. The time of planting is pro¬ 
tracted beyond the natural period of germination, and the tubers be¬ 
come exhausted by germinating in the pits; and when at last com¬ 
mitted to the ground, they are frequently planted in mould which has 
become dried up, and notunfrequently placed in manure which is al¬ 
so dry and withered, from improper separation or neglect; and are 
sometimes put into the ground so rough and ill prepared, that the air 
is freely admitted to the seed, to dry up any moisture that may re¬ 
main. If seed be perfectly sound and uninjured, it may be able to 
surmount the obstacles which improper management at the time of 
planting opposes to its germination ; but when injured and its pow¬ 
ers of germination weakened, it may fail to overcome them,” which 
views are strictly m accordance with the observations of the majori¬ 
ty of the numerous communications which have been recently made 
on the subject to the Highland Society, in consequence of a medal 
offered by them for the best treatise on the subject. 
In order also to ascertain the effect of planting the tubers and sets 
at different distances, a great number of experiments were made by 
the London Horticultural Society, with several varieties, upon pieces 
of ground of various measurement: thus— 
1. A plot of ground was divided into squares of four feet, in the 
centre of each of which was planted a whole tuber, a single eve, a 
set containing three eyes, and the whole surface of a tuber pared off 
so as to leave the eyes safe, but to remove the centre—a practice 
wh'ch is not uncommon in Scotland and Ireland. The result of 
which proved to be, in thirteen cases out of sixteen, in favor of the 
single eyes as compared with tubers; in nine cases out of sixteen, 
in favor of single eyes as compared with sets containing three eyes ; 
and, in ten cases out of sixteen, in favor of single eyes as compared 
with parings. 
2. Eight different whole tubers were planted in a row eight feet 
long and two feet distance from each other, and the result showed, 
“that in those varieties which were of very strong growth, producing 
large plants, the first plan, at wide distances, was the best; but, 
when the varieties were weak dr of a dwarfish kind, the lesser dis¬ 
tances were the most productive. Thus it may be assumed that in 
every case the difference will be in proportion to the vigor or debili¬ 
ty of the variety.” 
It being, however, thought desirable to repeat the comparison of 
whole tubers and sets, for the purpose of further illustrating the ad¬ 
vantages and disadvantages of close and distant cropping,°by trials 
with the varieties commonly in cultivation among those who supply 
the London markets, a quantity of early Champion potatoes was pur¬ 
chased by the society in the beginning of 1834, and a piece of ground, 
on which no potatoes had been previously grown, was selected for 
the purpose. No manure was employed, nor was the soil by any 
means in a fertile state for garden ground. The following account 
of the experiment was drawn up by Dr. Lindley, who, as one of the 
secretaries to the institution, attended to its management. 
“ The ground was divided into four equal parts. In one of these 
the rows of potatoes were as much as two and a half feet apart; in 
another, two feet; in a third, one foot and a half; and in a fourth, 
only six inches. Half of each division was planted with whole tu¬ 
bers, and half with sets cut to a single eye. The whole were com¬ 
mitted to the ground on the 27th of February; both the tubers and 
sets being in every case six inches apart in the rows, and nine inch¬ 
es deep.” 
“ On the 24th of April the points of the potatoes had reached the 
surface of the soil, and the next day about three inches of soil were 
drawn over them, for the purpose of protecting them from ground 
frosts, which in low and flat places, like the society’s garden, are still 
prevalent at that time of the year. By the 2d of May the whole sur¬ 
face of the ground, in the division where the rows were only six inch¬ 
es apart, was a mass of entangled stems. By the 20th of the month, 
the stems in the division where the rows were one foot and a half 
apart had nearly covered the ground; and in a week after, those in 
the two feet division were in the same state ; but the ground was 
not covered during the whole season, where the rows were two feet 
and a half apart. 
« The shoots from the whole tubers were, in all cases, much strong¬ 
er than those from the single eyes, but they began to be prostrated 
in the six-inch division, on the 29th of May, and the whole of them, 
in all the divisions, were in the same state by the 27th of June ; 
while the stems from the single eyes continued erect till they began 
to turn yellow and wither, in the end of August. This will probably 
account for the superiority of sets over whole tubers : could the crop 
be protected from winds, and the stems of the tubers prevented from 
breaking, I have no doubt that tubers would yield the largest crop; 
but their very vigor makes them brittle, and once broken, they are 
no longer able to perform their functions perfectly. 
“The greatest length to which the stems attained was two feet: 
the principal part of them attained that length, but many did not ex¬ 
ceed one foot and a half; and those in the division where the rows 
were at that distance were the most uniform in their appearance. 
The important inferences to be drawn from this were afterwards 
shown by the result.” 
“ On the 26th of September the whole crop was taken up, freed 
from mould, and weighed. Where the rows were only six inches 
apart, a number of new potatoes were partially decayed, and a very 
large proportion was too small to be fit for use. The most uniform 
size was obtained from the division where the rows were two feet 
apart. The result of the experiment was as follows : 
Distances 
between rows. 
ft. in. 
Sets. 
Weight of seed 
required per 
acre, 
lbs. 
Estimated produce per 
acre, deducting the 
weight planted, 
tons. cwts. lbs. 
r J 
i Whole tubers. 
6,497 
18 
8 
4 
z 
i Single eyes. 
1,470 
15 
19 
82 
o < 
j Whole tubers. 
7,426 
16 
8 
46 
z 
1 Single eyes. 
1,794 
24 
0 
87 
1 
6 \ 
; Whole tubers. 
11,764 
21 
4 
72 
1 Single eyes. 
2,055 
22 
16 
102 
0 
a < 
j Whole tubers. 
32,065 
16 
17 
91 
o 
( 
) Single eyes. 
5,008 
16 
17 110* 
* The quantity of seed, and the estimated produce per acre, were calculated 
upon the quantities sown and gathered, which are stated in the original table. 
