THE CULTIVATOR. 
299 
with their safety. They are then immediately hand 
hoed, and in the course of ten days they are again horse 
and hand hoed, and slightly molded with the double 
mold plow. The growth is now very rapid, and just 
before the stems from the contiguous drills begin to meet, 
the grubber is again passed between the rows, this time 
narrowly set, and drawn by two horses, so as to loosen 
the soil to as great a depth as possible. They are now 
finally earthed up, and if the crop is good the stems soon 
begin to interlace, and in a week or two present an un¬ 
broken surface of leaves and bloom. 
Early in October, the crop is raised either with the 
fork or plow, and stored partly in houses, and partly in 
long conical heaps on the surface of the ground, which 
are slightly covered with straw and then with earth to 
the depth of six or eight inches. The earth for this 
purpose, is obtained by digging a trench along the sides 
of the heap, thus forming a drain which prevents any 
water from lodging in the interior. These heaps or 
<£ pits 1 ’ as they are termed, are generally from five to 
five and a half feet in width, and four feet in height, 
and are occasionally of great length, containing some¬ 
times 6000 bushels. 
The yield of this crop varies from eight to fourteen 
tons, but there have been instances of eighteen and 
twenty tons per Scots acre, of marketable potatoes being 
raised. 
In the district around Edinburgh, the potatoe crop is 
of the first importance. This will be readily under¬ 
stood, when I mention that here four contiguous farms 
have always 200 or 220 acres under it, and as the ma¬ 
nure when brought to the field does not cost less than 
7s. per ton, it will be seen, that if to this we add rent, 
seed, and labor, a sum little short of £1200 is involved in 
the growth of fifty acres, exclusive altogether of any 
profit. The price which has been obtained for these 
two years past, was 45s. per ton, but some years it has 
reached 60s. and 80s. The moderate price of late years, 
has been in a great measure owing to the low price of 
oatmeal, and a considerable importation from Ireland. 
The use of portable manures is gaining ground great¬ 
ly as an auxiliary to the ordinary manure. Guano on 
any soil at the rate of three or four cwts. per acre, and 
rape dust on strong soils, at the rate of six or eight 
cwts.. sown on the drills above the dung, are found to 
yield a very remunerating profit. Mixtures, contain¬ 
ing the elements of the stem and tubers, have also 
been applied with great success, and as chemistry ad¬ 
vances, they will no doubt be much more commonly 
used. As our scientific knowledge becomes more per¬ 
fect, and more diffused, those unsuccessful attempts at the 
application of principles to practice will be more rare, 
and when they do occur, instead of throwing discredit on 
science, and producing doubt and hesitation, they will be 
referred to the true cause—the errors or want of know¬ 
ledge of the operator. 
I am, &e. Jno. Girdwood. 
LETTERS FROM MR. HORSFORD—No. VII. 
Giessen, June 20th, 1845. 
Mr. Tucker —I am reminded by an American friend, 
that an account of a day’s life in Geissen, would be inte¬ 
resting to your readers; and willing to minister to their 
gratification, at least in an effort so inconsiderable, I 
will give you my yesterday’s history. 
At half past five, I was awakened by the servant to 
whom I am indebted for all my home comforts. She 
brought me the biscuit and cup of milk which consti¬ 
tute my regular breakfast, and soon after my coat and 
boots. At ten minutes past six, I was with about fifteen 
other young chemists, in Dr. Fresenius’ little Laboratory, 
listening to a Lecture upon the science of Sugar Manu¬ 
facturing—the detection of impurities—the distinction 
between grape, cane, and milk sugar, See., &c. You 
may be a little surprised to learn that this already 
famed man, is but twenty-six years old—one of the 
most indefatigable and industrious of men. This lec¬ 
ture was one of a course upon Economical Chemistry, 
which is given two days in the week. On two other 
days, at the same hour, I hear him upon qualitative 
and quantitative organic analysis; and on Monday of 
each week the same hour and the one following, are ap¬ 
propriated to blow-pipe investigation with Prof. Will, 
who in Giessen is second only to Liebig, and is indeed 
accredited one of the first organic chemists of the day. 
From seven to eight, I was seated with five or six 
others, in Liebig’s auditorium, listening to Prof. Ropp, 
on crystallography, and determining crystalline forms. 
The lectures of this gentleman are given three mornings 
of each week, and to them is added an exercise in crys¬ 
tallographic drawing, in the afternoon of Saturday, from 
two to five o’clock. 
At a quarter past eight I was at work in the labora¬ 
tory. [Note. —It is almost impossible to escape an 
almost unparalleled use of the first personal pronoun, in 
this personal history, and I beg that as this is by far the 
simplest mode of making a relation, I may be indulged 
in it, and moreover, that the apology which is by me 
deemed due, shall be sought in an honest wish to satisfy 
the not censurable curiosity of my friends in relation to 
the Giessen chemical school, and student life in Ger¬ 
many.] Just now, my first duty in the laboratory, is 
the microscopic examination of some fluids in ferment. 
The essential cause in fermentation is not yet settled 
and is full of interest. This occupies me but a few 
moments. I then go to labors with ash and mineral 
analysis, which it would be impossible to detail, and to 
organic combustions, which alternate with the former, 
as processes are waited for, to preparations of re-agents, 
&o. At five minutes past eleven, I was listening with 
about ninety others to Liebig’s lecture. It is every day 
of the week. His lecture, always brilliant, and yet pos¬ 
sessing this attribute quite independent of experiments, 
continued till about half-past twelve,—sometimes it con¬ 
tinues till nearly one. 
I received, two or three days since, the Cultivator, 
containing my first impressions of our great teacher; 
and warm as was my admiration when those impressions 
were committed to paper, it has only increased with 
each day’s acquaintance. It is as impossible to give an 
adequate idea of these lectures, as it would be to revive 
Raphael’s studio and its master through the letter of a 
correspondent of this century. Pens, paper, and lan¬ 
guage have an humbler office. In the lectures upon hy¬ 
drogen, we have, I presume, from forty to fifty experi¬ 
ments daily, and in others, scarcely a single experiment, 
and yet all quite alike interesting. Indeed, in the re¬ 
view, I find it much more difficult to recall experiments, 
than the statements he made—so rich in thought are 
these every-day communications. This is their distin¬ 
guishing attribute. It is the practice in all the lectures 
to take notes in ink of every proposition, experiment, 
explanation, and application—otherwise it would be be¬ 
yond human power to recall any proportion of the mass 
of fact and theory which is given. I use this word 
theory not in the sense of censure, which is the more 
frequently mistaken conception of its meaning. A the¬ 
ory is an explanation of phenomena. 
The lecture was upon arsenic, with all the modes for 
its detection in organic matter, and then an especial 
course for its unvarying detection, without compounding 
with antimony. As it is exceedingly simple and may 
be of service, I will give it you. 
Put the food, stomach, intestines, or other matter sup¬ 
posed to contain arsenic, either as the lower or higher 
acid, in a vessel containing water—boil with the addi¬ 
tion of hydrochloric acid, and successive additions ol 
powdered chlorate of potash. After boiling till the or¬ 
ganic matters rise to the surface, or coagulate—filter, 
and all the arsenic will be in the liquid as arsenic acid. 
Now boil with sulphurous acid to reduce the arsenic to 
arsenous acid; and continue boiling till all sulphurous 
acid is expelled. Then add sulphuretted hydrogen, ei¬ 
ther from water saturated with it, or by the gas—and all 
the arsenic will be thrown down as a sulphurous com¬ 
pound. Filter, and there will remain upon the paper, 
beside the sulphuret of arsenic, perhaps some organic 
matters. Re-dissolve with ammonia, and the organic 
matters remain in the filter, while the sulphuret goes 
through. Hydrochloric acid throws down the sulphuret 
