xt7msb3wtd7m https://exploreuk.uky.edu/dips/xt7msb3wtd7m/data/mets.xml Peter, Robert, 1805-1894. 18841877  books b97-22-37599428 English Yeoman Press, : [Frankfort : Contact the Special Collections Research Center for information regarding rights and use of this collection. Hemp Kentucky. Buckwheat Kentucky. Chemical examination of the ashes of the hemp and buckwheat plants  : with remarks on its bearing on hemp culture in Kentucky / by Robert Peter. text Chemical examination of the ashes of the hemp and buckwheat plants  : with remarks on its bearing on hemp culture in Kentucky / by Robert Peter. 1884 2002 true xt7msb3wtd7m section xt7msb3wtd7m 











GEOLOGICAL SURVEY OF KENTUCKY.



N. S. SHALER,



DIRECTOR.



CHEMICAL



EXAMINATION



             OF THE ASHES OF THE


HEMP AND BUCKWHEAT PLANTS,

          WITH REMARKS ON ITS BEARING ON



HEMP



CULTURE



IN KENTUCKY.



BY ROBERT PETER, M. D., ETC., ETC.,
      CHEMIST TO THE SURVEY.



439

 This page in the original text is blank.

 

CHEMICAL       EXAMINATION        OF THE      ASHES OF
   THE HEMP AND BUCKWHEAT PLANTS, &c.


   The hemp crop is of considerable importance in Kentucky
agriculture, more especially in the richer portion, called the
Blue Grass region, where the soil has been formed by the dis-
integration of the fissile layers of the lower Silurian lime-
stone-rich in the mineral elements of plant nourishment.
  According to the State Auditor's report, the gross amount
of hemp fibre produced in our State was 18,981,819 pounds
in i872, and 21.375,306 poUiiids in the more productive, moist
season of 1873.
  Of this latter quantity seventeen counties, situated wholly
or in part in the Blue Grass region, produced 21,194,445
pounds, and the five counties of Bourbon. fIayette, Jessanmline,
Scott, and \W'oodford produced 1 7,95 1 ,350 pounds. Masons
County, tile next in this indcLstry, leaving also raised S28, oo
pounds. It is, therefore, evidently a crop which is believed to
be profitable only on1 our richest lands. The soil which best
suits it is the rich, pervious, and well-drained loanm w'ell
charged with humuzis or the dark mould resulting from veg-
etable decomposition, such as results from the completely
decomposed sod of recently cleared woodland pastures, or
blue grass or clover ground, well plowed and made thorough-
ly fine alldl uniform in texture. Such land, in a favorable
season. has been known to produce as much as 1,200 pounds
of hemp to the acre, and it will yield an average of about 8oo
pounds for ten to fifteen years in succession, if properly man-
aged, in ordinary seasons. As the price of hemp rarely falls
below one hundred dollars per ton of 2,240 pounds, and this
crop usually brings in cash, the great value of this industry is
evident.



VOL. I.-CHEM. 29.



441

 
CHEMICAL EXAMINATION OF THE ASHES OF



  The hemp plant, under favorable conditions, is of most rank
and luxuriant growth, attaining on our rich lands a height of
ten to fourteen feet in favorable seasons, even when sown so
thick, as is the practice, that it is closely crowded, and so com-
pletely covers the ground that not a weed can grow amongst
it. It therefore requires a soil which can readily and quickly
furnish to it the mineral elements necessary to its rank and
rapid development, and at the same time furnish the large
supply of moisture it requires without losing that highly
porous condition and absorbing power which invites the pen-
etration of the gases and vapors of the atmosphere, on which
this plant is so greatly dependent for nourishment and growth.
  The well-drained loam of this Blue Grass region, which is
charged with black vegetable mould or humus, offers these con-
ditions; the humus not only having great power of absorption,
but containing in a soluble and available state the mineral
elements of plant nourishment, and, moreover, acting as a sol-
vent for those which are contained in the earthy constituents
of the soil itself. We can therefore readily understand why
the hemp plant thrives upOtI such land; but why so luxuriant
a growth can be maintained on the same surface for ten to
fifteen years in succession, without any material exhaustion of
the soil, is another question.
  The observing hemp farmer has long since arrived at a cor-
rect conclusion in this respect. He saw that while this most
luxuriant plant produced an immense green crop, alicl required
the richest soil to supply its rapid demand for nourishment
during its short season of growth (of four months only), yet
all its leaves and other green tissues, together wvithi all that is
removed from it in the process of dew-rotting, in the ordinary
mode of hemp culture, are restored to the soil which produced
it. and nothing is sold and carried off from the land but the
cleaned hemp fibre, which, if well cleaned, contains very little
but atmospheric elements, the removal of which can therefore
cause but very little deterioration of the soil.
  Moreover, during a great part of the year the ground is
more or less shaded and protected, first by the growing plant,
442



4

 
THE HEMP ANDI) B1UCKWH-EAT PLANTS, &C.



then by the roots left in the ground after cutting, which some-
what diminish the washing action of rains and improve it in
their gradual decay, as do also the leaves which fall and the
hemp when spread on the ground to dry, after being cut, and
lastly, when it is spread out upon it in the winter process of
dew-rotting. as it is called, during which all the readily decom-
posable parts of the plant are washed out and decomposed by
the rains and dews and the action of the air; enriching the
surface soil beneath.
  Managed in this way, and commencing with suitable rich
land, the scientific observer understands, that although the
growing plants may temporarily draw heavily on the soil for
the mineral (earthy) ingredients necessary to their growth,
amongst the most important of which are potash and the
earthy phosphates, yet in the subsequent processes, the most
of these are returned to the ground again in the decay of the
leaves and other green parts, and in the soluble and decom-
posable matters which are leached out of the stems in the pro-
cess of rotting; and that any small loss of these from the
arable surface which may occur from the sale of the hemp
fibre may be more than compensated by the action of the
tap-roots in bringing them tip from the lower strata of the
ground.  He understands further, that all the mineral ele-
ments thus restored, being left in organic combination in what
is termed the humus or vegetable mould which results from
this decay, are in a very soluble condition, and most available
for the quick nourishment of the subsequent crop.
  If the hemp plant, instead of being dew-rotted on the
roTUnd on which it had been growvn, is entirely removed from
it and submitted to the process of wvater-rotting, the culture
becomes eminently exhausting to the landl; mainly because
so much of the elements of fertility is necessarily carried off
in the water used. This was proved many years ago in rela-
tion to the flax crop of Ireland, in the chemical analyses of
the water in which the flax had been steeped, and of the plant
and the lint, by Dr. Kane; and experience to a certain extent
in this region, in the water-rotting of hemp, has given the
                                                          443



5

 
CHEMICAL EXAMINATION OF THE ASHES OF



same result. It is, perhaps, fortunate for our farmers, there-
fore, that this process, although several times proposed to
them, has never been received with much favor.
  The foregoing facts being of common experience, the writer
desired, by the chemical examination of the mineral or earthy
constituents of the hemp plant, as given in the as/h in different
periods and conditions of its growth, in different parts of the
plant, and the various stages of its preparation, to study more
fully the relations of this crop to the soil, and to understand,
if possible, the true reasons why it is not an exhausting pro-
duct when properly managed, as well as to learn the best con-
ditions for its successful culture.
  The first step in this investigation is to ascertain the aver-
age composition of the mineral ingredients of the entire hemp
plant as given by the chemical analysis of its ashes; and as
the works accessible to the writer give but very limited inform-
ation on the subject, he procured from his owvn farm, and sub-
mitted to this analysis, five different samples, produced in two
different seasons, grown under different conditions, and col-
lected in different stages of their growth.  The ashes of
these, obtained by careful incineration at a moderate heat,
were analyzed by the approved processes several compara-
tive analyses of the same ash having been mnadle to secure
greater accuracy-and the results are tabulated below in com-
parison with the average of two hemp-ash analyses published
in 1865 by Professor Emil Wolff, of the Royal Academy of
Agriculture, at Hohenheim, Wirtemberg, which are repub-
lished in the Appendix, page 378, of "How Crops Grow," by
S. W. Johnson.
  The samples examined may be described as follows:
  Samzple 4. Entire hemp plants, including roots, leaves, &c.;
collected on September 4th, 1874, when fully mature and
ready for cutting; grown on somewhat elevated, very rich
ground, the second year only from the broken up blue grass
sod of woodland pasture, which had not been previously
cleared or cultivated within the memory of the present race,
444



6

 
THE HEMP AND BUCKWHEAT PLANTS, &C.



but which had been the site of a large circular earth-work  
by the ancient mound-builders, and which seemed to have
been enriched by a long residence upon it of these prehistoric
people. The sample, notwithstanding the great fertility of
the land, was very small, in consequence of a continued droughit
which prevailed during the season of its growth, it not being
more than six to seven feet in height.
  SamAple B. Mature hemp plants, taken as it is usually cut, the
roots and a small portion of the stems being left in the ground,
and having only the top leaves, the others having fallen; col-
lected September, 1873; grown on the field described above
in a very, moist and favorable season, so that it was very tall
and large stemmed.   The samples were about twelve feet
high. Some hemp plants this year attained a height of four-
teen feet.
  Sample C. Six hemp plants entire, leaves, roots, and all;
collected, before full maturity, on July 27th, 1874, from the
-same rich field, in the verys dry scason. The plants were about
six feet high, and were in full leaf and in flower.
  SammpAe D. Entire hemp plants, including roots, leaves, and
immature seeds; grown on the experimental field selected by
my son. Benj. D. Peter,t for practical experiments in hemp
culture. This ground had been long in cultivation-at least
fifty years. This sample was grown on lot 3, to which about
200 pounds of plaster had been applied early in the growing
season. The sample was collected on September 8th, 1874.
The plants were quite small, not more than from five to six
feet high, in consequence of the continued drought of this
season and the condition of the land.
  Sample E. Similar to sample D; grown on the neighboring
lot 4, of this experimental field, under similar conditions, ex-
cept that no plastcr or any other fertilizer was applied to this lot.
A part of this lot 4, however, where a fence row formerly
stood, happened to be somewhat richer than any part of this
Fully described in Collins' History of Kentucky.
tSee Prof. N. S. Shaler's Report.
                                                         445



7

 

CHEMICAL EXAMINATION OF THE ASHES OF



or the plastered lot, as shown by the greater luxuriance of the-
growth of the hemp in that part.
  F. The average of the analyses of the ashes of two entire
hemp plants as given by Prof. Emil Wolff, as above stated.
  In this table, as well as in the following ones, the carbonic
acid of the ash is excluded in the calculations, for more com-
plete comparison of the proportions of the essential mineral
ingredients of the ash.

TABLE I. A. OF THE CHEMICAL COMPOSITION     OF THE ASH OF THE
ENTIRE HEMP PLANT, CALCULATED IN loo PARTS OF THE ASH, WITH
EXCLUSION OF CARBONIC ACID.

                           A.    B.     C.     D.    E.     F.

Lime.                    38.482 31.299 48.689 50.6 3 45.263  43.4
Magnesia... . ..          8.558  6.017 6.445  8.576 11.225    9.6.
Potash.. .. .. . .. .. . 37.475 43.739 29.11823.519 23.933   18.3
Soda..    .. .. .        .378    1.438  1.280  .472   . 9     3.2
Phosphoric acid..... .. .  8.667 14.164 10.38411.721 13.233   i l.6
Sulphuric acid.... .. .. .  2.272  I.622  .940  1.472  1.445    2.8
Chlorine... .              .984   .522  .640   .301   .273    2.5
Silica..... .. . .. .. .  3.181  1.199 2-749  3.316  3.342    7.6

Per cent. of earthy phosphates . . 18. i86  29.773  21.692  28.460  27.427 .

Per cent. of ash to the air-dried
plants, carbonic acid excluded.  4.223  2.563  5-055  4.126  4.203    4.6.

Per centage of ash, carbonic acid
included...... . .. ..  5.569  3.357  6.754  5.288 5 346 .

  This table shows some notable differences in the ash pro-
portions and composition. For example, sample B, grown in
the moist season, as compared with the others grown during
the drought, gave a smaller ash per centage to the dried
plants; its ash contains smaller proportions of lime. magnesia,
and silica, and larger proportions of potash, soda, and phos-
phoric acid.
  The  immature   sample   C, gathered   in July, as compared
with the other samples (A, D, and E) of the same dry season,
which were gathered in September, shows a larger per cent-
age of ash to the dried plants.
446



8

 

THE HEMP AND BUCKWHEAT PLANTS, &C.



   The samples D and E, grown on the old land, while they
give about the samne average of ash to the dried plants, show
a smaller proportion of potash.
   Not much importance is attached to the proportion of silica,
which is evidently stated much too high in the analyses quoted
by Wolff.   The hemp plant, being somewhat viscid on its ex-
terior, always has more or less fine silicious dust adhering to,
it, derived from the soil, which cannot be removed by wash-
ing the plants.  Thi' the writer attempted to exclude, in his
analyses, by dissolving the ash in diluted acid (nitric or chloro-
hydric), and excluding all that remained undissolved as most
probably fine earth accidentally adhering to the plant. This.
may, in some cases, be a slight cause of error, but probably
not so great as the retention and analysis of the adhering
fine dirt with the plant ash, which seems to have been done
in the analyses quoted by Wolff. For the same reason the
alumina and iron oxide were also excluded.
  The real significance of these differences of proportion and
composition of these ashes can better be seen where the com-
parison is made with the proportions of the dried plants them-
selves to the several ingredients of the ash, as given in the
following table:

TABLE 1. B. OF THE QUANTITIES OF THE ASH INGREDIENTS IN 100 PARTS
    OF THE AIR-DRIED HEMP PLANTS, CARBONIC ACID EXCLUDED.

                           A.    B.     C.     D.     E.    F.

I.ime... .. . .. .1.. ..  i.624  0.802  2.461 2.10   1.968    1.74.
Magnesia... . .. ..        .361   .154   .312   .356  .475     -30
Potash...... .. . .  .... 1.582  1.121  1.472   .977 1.012    .74
Soda.  .   .   .   ...... . ..    oi6   .037   . o65  .019 a trace.  . E
Phosphoric acid....    ..   .366   . ;63  .525  .488   .560     .47
Sulphuric acid  ..           9o6  .042   .047   .o6i  .06z     . ao
Chlorine.         ..... . .. ..    041   .013   .022  .012   .011     .10
Silica..... . .. .. . ..    134   .031   .139   .135  .141     .30

Per cent. of earthy phosphates . .  .768  .763  1.103  1 . 182  1.150 .

Percent.of ashtodriedplants. . 4.223  2 563  5.055' 4.126  4.203  4.-a

0 See Wolff's tables, " How Crops Grow," page 383. Calmulated to the dried plants.



9

 
CHEMICAL EXAMINATION OF THE ASHES OF



  This table shows, that while the smallest proportion of min-
eral or ash ingredients, to the dried plants, was given in the
season when the hemp had a luxuriant growth because of the
regular supply of moisture, the difference was occasioned
mainly by the greater quantities of lime, magnesia, and silica
in the plants of the dry season, and not by any material
variations in the proportions of the alkalies or phosphoric
acid.
  It is well known that the external tissues of all growing
plants become more or less charged with earthy salts, espe-
cially carbonates of lime and magnesia with some phosphates,
which have been carried from the soil to their surfaces in solu-
tion in water containing carbonic acid (which is in all the water
of the soil) and left there in a form insoluble in water upon
the escape of that acid and the evaporation of the water which
brought them up.  As all the moisture of the fertile earth
contains this solution, which is drawn up and evaporated from
the general surfaces of the plants exposed to the air, it can
readily be seen, that because of the greater evaporation and
the more concentrated nature of the soil solution, in the dry
season, there must necessarily be a larger accumulation of this
surface deposit in the dry than in the moist or wet season, when
evaporation is measurably checked. For the same reason the
ash per centage of the leaves and bark of plants is greater than
that of the interior parts, and that of the leaves of deciduous
plants greater than that of the leaves of evergreens, which
give off less water by evaporation.
  The effect of this evaporation has very justly been com-
pared to the deposit of the limestone crust in the steam-
boiler and the formation of stalactites in caves; and this
irregular increase of the ash per centage causes many appa-
rent discrepancies in the mineral ingredients of plants, and
increases the difficulties in the chemical study of plant nourish-
ment; for while it is generally admitted as fully demonstrated.
that certain mineral ingredients, to be found in the ashes of all
vegetables, are essentially necessary to their growth, it must
be acknowledged that some or some portion of these ingredi-
448



gO

 
THE HEMP AND BUCKWIIEAT PLANTS, &C.



ents are of no more significance than the incrustation in the
steam-boiler; being mere accidental deposits on the surface,
the result of the escape and evaporation of the agents, water
and carbonic acid, which held them in solution in the sap of
the plants and in the wvater of the soil.
  In the same manner may wve explain the influence of a dry
season in increasing the fertility of the surface of the soil;
the soil solution, on the evaporation of the water, leaving its
dissolved salts and other ingredients upon the surface; so
that seasons of long drought are usually followed by others
of great productiveness when there is sufficient moisture.
  The larger ash per centage of sample C is mainly due to
this cause; the leaves not having fallen, which yield a very
large proportion of ash.
  The ashes of samples D and E, grown on the old land in
the very dry season, while not differing much in their general
weight-proportion to the dried plants, show more lime and
less alkalies than that of the hemp grown on the richer land.
For some reason not immediately apparent. perhaps because
of a previous buckwheat crop, they gave rather more than the
average quantity of earthy phosphates.
  In the usual mode of management of the hemp crop the
leaves mostly fall on the ground on which it is grown. A
large proportion of them drop before the hemp is cut, more
fall when it is spread on the ground to Ir), after cutting, and
when it is taken up to be stacked. It would be well, doubt-
less, to beat off, in this process, all the leaves that can thus
be separated. so that they may be more regularly distributed
over the soil than if thrashed off when stacking it. It is also
the general practice now to cut the hemp as nearly as possible
to the surface of the ground, and leave the roots, with a few
inches of the stem attached, to rot in the soil.
  In order to ascertain the relative fertilizing influence of the
leaves and roots, three hemp plants were collected, July 25th,
i864, in (lze dry) season, from the rich field above described.
These, one male and' two female plants, were about six to
                                                           449



I I

 

CHEMICAL EXAMINATION OF THE ASHES OF



seven feet high. The leaves, stems, and roots, carefully sep--
arated and thoroughly air-dried, weighed as follows:
Thie keaves weighed 23.916 grammes, equal to about 30. per cent. of the whole plant.
The roots''    7.433                    9.3
The sterns'   48.430 o'                60.7
  These were separately incinerated and their ashes analyzed,
with the following results:

TABLE II. OF THE RELATIVE ASH INGREDIENTS OF THE LEAVES, ROOTS,.
       AND STEMS OF THE HEMP, CARBONIC ACID EXCLUDED.

                            THE LEAVES.   THE STEMS.    THE ROOTS.
                         In0 p'ls In 1oo pts In 100 pL, In 1to p'Ls Inn ao LS In C- p'ts
                         of ash.  of drie:d  of ash,  of dried   of dried
                                 leaves      slems.        room.

Lime.............       . 48.819 4.992  23.371 0.949  O0.368  0.71.
Magnesia.. .. ..        ,  5.726  . 585  S. 80, .194  8.297    .291
Potash..                  27.955 2.858 )49 599 i.659  52.233  X.8-9
Soda......4.. . .. ..659.2.236 .024
Phosphoric acid.... .. . .  9.264  .947  13. 374  .447 15.164   .531
Sulphuric acid... .. .. . .  2.209  .226   1.215   .040  1.344   .047
Chlorine.         ..... .. .. . ..   171  .017    .576  .019   .405    .014
Silica.... ...    .. .. . .  5.6:o  .575   1.o62  .035  2.189    .077


Percent. of phosphate-,   19.160 1.959  28.158 0.942 26.885   0.949

Per cent. of ash....... ..  .. . . 110.225   - -3.346 - - -  3.502-


  By examination of the above table it is to be seen, that the
leaves of the flowering hemp contain more of the essential.
mineral ingredients of the soil than all the other parts of
the plant; constituting, as they do, about 30 per cent. of the
whole plant in the air-dried state, and yielding 10.225 per cent.
of their weight of ash, the carbonic acid being excluded; while-
the stems and roots, which together form the remaining 70 per
cent. of the weight of the plant, give an average of less than
3.5 per cent. of ash.
  Nor is this great excess of the ash proportion in the leaves
due entirely to the influence of the greater evaporation which
takes place on their surfaces, causing a deposit or incrustation
of lime and magnesia salts and silica of the nature of stalag-
mites; for we see that whilst the amount of silica in the leaves
is nearly fourteen times greater than that in the stems, and
450



I 2

 
THE HEMP AND BUCKWHEAT PLANTS, &C.



more than seven times greater than in the roots; the lime
more than five times as great as that in the stems, and seven
times more than in the roots; the mniaixesia three times more
than that in the stems, and twice as much as that in the roots;
the pho.op/worc acid and phosphiates and the a/kahi's are in nearly
double proportion in the leaves also, and the sulphuric acid
five times greater in them than in the stems, and about four
times greater than in the roots. So that whilst the leaves,
when in their fully matured state or when they naturally fall,
may possibly contain scarcely any but the less soluble salts
which may be left in their tissues on the evaporation of the
carbonated water which held them in solution in the sap, they
contain, when in the growing, active condition, like all other
green herbage, a very large proportion of salts of potash.
and of all the mineral elements of plant nourishment, and
hence may greatly enrich the soil on which they decay. It is
obviously to the interest of the hemp farmer, therefore, so to
manage as to spread them as regularly as possible over his
hemp ground.
  The dried hemp plants are allowed to remain in the stack
until the cool season of early winter, when they are generally
spread out evenly upon the same ground on which they had
been grown, to undergo the process of dew-rotting. The
hemp is permitted to remain on the ground until, by the action-.
of the atmospheric waters and other agencies. it has become
so far decomposed that all its soluble parts and soft tissues
are removed and washed into the soil beneath or dissipated in
the air, and the tough hemp fibre can be easily separated from
the more woody portion of the stems. It is then taken up,
"braked" out, and the clean merchantable hemp fibre sep-
arated from the "hemp-herds," or "henmp shiives "-the broken
fragments of the woody parts of the stems-which are usually
burnt up by the hemp-brakers on the spots where they fall
near their hemp-brakes.
  In order to study the changes which occur in the mineral
constituents of the hemp during this process of dew-rotting,
samples of dew-rotted hemp plants, ready for the brake, were
                                                         45'



1 3

 

CHEMICAL EXAMINATION OF THE ASHES OF



gathered, in December, from the two lots of the experimental
field above mentioned, of the crop of the dry season of i874.
These were thoroughly air-dried, incinerated, and their ash
submitted to analysis, with the following results:

TABLE Ill. OF THE ASH ANALYSES OF DEW-ROTrED HEMP PLANTS,
                  CARBONIC ACID, &c., EXCLUDED.

                                  (D) SAMPLE FROM LOT 3. (e) SAMPLE PROM LOT 4.
                                  PLASTEMED. (SEE D.)  NOT PLASTERED. 'SER M.)

                                  In loo parts of In  part oft In tO parts of In loo pars of
                                    ash.   dred hemp ash.   dried hemp
                                           plants.          plants.

Lime .. . .. . .. . .. . .. . .    68.846    1.235   63.651    0.942
Magncsia. .. . .. . .. . ..   ..    8-335      149   8-343     .124
Potash... ..   .. . ..        ,     5.V716    102     5.682     .084
S&da.. . . .. . .. . ... .            429     .Co 8    . 760    .012
Phosphoric acid.13.979                         .251   15 713     .233
Sulphuric acid..965                            .017    1-552     .023
Chlorine.... . .. . .. . .. . ..     .050     .O       .042     .001
Silica... .. . . .. .. . . .. . .   1.680     .030    4.257     .o63


Pcr centage of earthy phosphates.27.144             .487   29.920     .443


Per cent. of ash to the dried rotted hemp..     .. ...  1-793 .....       1.480


  On comparing these results with those given in tables I. A.
and I. B., in the columns D and E, where the results of the
analyses of the ashes of this same growth of hemp are given
in the unrolled state, it will be seen that a great diminution
has taken place in the amount and proportions of the ash and
its several ingredients.
  To exhibit this diminution of the ash ingredients, which
takes place in the ordinary process of dew-rotting, we place
the averages from table I. B. and the above table side by side
in
452



.14

 

THE HEMP AND BUCKWHEAT PLANTS, &C.



TABLE TV. COMPARATIVE VIEW OF THE ASH OF THE UNROTTED AND
THE DEW-ROT' ED HEMP PLANTS, CARBONIC ACID BEING EXCLUDED.
                               Aved aeof D Averageof U)
                               and E. Un- .nd E. IDew- Iroportions rcrnovcd Ly dew.
                               rotted hemp  rotted hemp  rotting.
                               plants.  plants.

Lime.......    ...... . . .  .    2.o0,6   1.o89 About one half.
Magnesia... .. .. . .. . .. ..     .415     .136 Nearly two thirds.
Potash. ....   ........ ..  .       995     .C93 More than nine tenths.
Soda      .        ....019                  .010 About one half.
Phosphoric acid . . .... . . . . . . 524  .242 Nlore than one half.
Sulphuric acid. .   ....................o6i  .020 About two thirds.
Chlorine. . .. . .. ...  .....     .01       l. oo l Ten elevenths.
Silica.                 ...... .. . .. . .. ..                   Nearlytaco thirds.

Per cent. of earthy phosphates.  x. i66   .465 More than onc half.

Per cent. of ash to the dried plants . . .  4. i65  1.66 'More than one half.

  When we also take into consideration the fact that the dried
hemp plants lose at least one third of their weight in the dew-
rotting, we can judge how large a proportion of the essential
mineral ingredients are restored to the soil in this process.
  The above table also shows us that the imore soluble ingre-
dients, such as the alkalies, &c., are removed from the plants
in the larger proportions.
  These analyses and comparisons enable us clearly to un-
derstand why the culture of hemp, when judiciously managed,
especially when it is spread out and dew-rotted on the same
surface on which it was grown. is so little exhausting to the
soiI, as compared with the method in which the water-rotting
process is used.
  In order to ascertain how much of the essential elements of
the soil are carried off in the merchantable product-the hemp
fibre as ordinarily sold-analyses were made of some of this,
both in the usual condition as it is to be found in our hemp
factories, and after it had been well washed with water to
remove from it as much of its adhering dirt and soluble matter
as possible.
  Two samples of the "hemp-herds," or refuse woody por-
tions of the stems, separated in the operation of braking,
were also incinerated, in the air-dried state, and the ashes
                                                               453



I;5

 


16         CHEMICAL EXAM1INATION OF THE ASHES OF


submitted to chemical analysis. The results are given in the
following table:

TABLE V. COMPARISON OF THE ASH INGREDIENTS OF DEWV-ROTED
     HEMP FIBRE AND HEMP HERDS, CARBONIC ACID EXCLUDED.

                4E14P  FiSIIE, UN-  HEMP FIBRE,  HEMP-HERDS, 1873.  HEMP "H EtS, 1874.
                I  W- A ,HEu .  I   WASHED.  MOIST AS O LAS IVV SEASO, SEM.



Limle
M6gniia.        .
Poah...      .
Sools.a  
Phosphoric acid....
Sulphuric acid
Chlorine .
Silica            .

Per cent. of earthy phos-
phame.....  .



In loo pt's In loo' p It
of ash.    of dried
       hemp .

 59 960 0.984
 8S. Il - l 41
 7-3;'  . I 21
   .712  .012
   13.852 .200
   I.710  .-29
   cv9'  . 00
   5.621  .X92  

             1:
 31.567  .;   i
             I.



In top'ts In moop'ts In   p'  In soop'ts ID loop'ts In zoop'1ts
of ash.of hemp.of a,of driedof ash,of dried
                    herds.       herds.

 68.694 0.722 51.998 o.446 6z.992   0.676
 622.2   o65  8.426   .072 8.966    .097
 3.789  .040 19.615  .168  8.670    .093
 .Sol  .-08   .915   .-08  .754    .o..
 15,.335 .x6i 14.401  .124 12.215   .131
 .487  .05   2.16    .017  2.138   .023
 .048  .0.. a trace.a trace. a    trac.
 .624  .049  2 629   .022  4.465   .048


 29.486  .310 29 275  .251 24.807   .267



Per cent. Of ash to Lhe air-  I
dried material.       1.64 2        1.051         -.8           .076

  The hemp fibre, which was analyzed in the ordinary un-
washed condition, wvas obtained from a factory in Lexington.
It was of the crop of 1874, dark colored, and containing, per-
haps. more than the average quantity of dirt or fine soil adher-
ing to it. Washing with cold water removed some but not
all of this adhering dirt, as well as much of the soluble matters
contained in it, reducing the per centage of the ashy residue
more than one third. Had it been thoroughly cleaned and
bleached the ash per centage would have been still more con-
siderably reduced. All the nitrogenous matters, holding phos-
phates in a comparativel) soluble condition, all the alkaline
salts, wvould thus be dissolved out, and very little else than
silica, with a small proportion of the earthy carbonates, would
be left in the clean henip fibre; so that exhaustion of the soil
from its production would be quite insignificant.
  Calculating on the data of the above tables, we find that
an average crop of hemp of 8oo pounds to the acre removes
from the soil only a little more than thirteen pounds of ash
ingredients, or, when in the washed condition, less than eight
pounds and a half, while it is well known that a crop of wheat
of twenty bushels takes nearly twenty pounds in the grain
454



I-

 

THE HEMP AND BUCKWVHEAT PLANTS, &C.



alone; a crop of fifty bushels of corn removes more than thirty
pounds in the grain alone, and a crop of tobacco of one thou-
sand pounds, more than one hundred and seventy-six pounds.
   When we compare the relative proportions of the ingre-
dients of these sev