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340 


at present without any comment upon it), that I have observed a 
jaundiced condition produced by the operation on the sympathetic 
with the injection of the acid. The urine has been deeply tinged with 
bile, and has given the characteristic play of colours upon the addi¬ 
tion of nitric acid. In the experiments with the injection of the acid 
alone, it has been a matter of constant observation that a flow of bile 
has been excited into the duodenum and towards the stomach, the 
pyloric extremity of which has been highly tinged of a yellow colour. 

Although a diabetic state of the urine may be thus artificially in¬ 
duced, apparently by the direct chemical agency of an acid upon the 
liver, yet I am not prepared to say that, beyond the addition of 
another significant fact to our knowledge upon this matter, any at 
present available assistance has been gained towards unravelling the 
nature of the diabetic disease. Possibly in some cases an insufficiently 
alkaline state of the portal blood may he the cause of a temporary 
slightly saccharine state of the urine ; but from the observations I have 
conducted upon diabetics, I certainly am not permitted to think that 
such is the cause of the well-marked diabetic disease. The immediate 
cause of the production of sugar in idiopathic diabetes, and in diabetes 
artificially produced by operations upon the nervous system (the sympa¬ 
thetic and cerebro-spinal), still remains an open point for discovery. 

Usually in my experiments with the acid injections the liver has 
been found fairly charged with amyloid substance; but in a few instances 
an absence of this principle has been observed, although only a short 
time has elapsed between the injection and the period of destruction 
of life. 

X. “ On the Chemical and Physical Conditions of the Culture of 
Cotton.” By J. W. Mallet, Ph.D., E.C.S., Professor of 
Chemistry in the Medical College of Alabama. Communi¬ 
cated by Robert Mallet, Esq., F.R.S. Received June 4, 
1861. 

(Abstract.) 

This communication embraces the first portion of an elaborate 
physical and chemical investigation, in which the author has been and 
is still engaged, upon the scientific conditions involved in the success¬ 
ful agriculture of the cotton plant. To this train of research he has 


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brought peculiar advantages, holding his professorial chair in the great 
cotton-growing State of Alabama (North America), having been the 
editor of the Government Geological Report of that State, and having 
had placed at his disposal (for experiment and comparison) by the 
Indian Government, a magnificent collection, specially made, of the 
various cotton soils and plants of India, as well as the like from other 
Powers. 

The author remarks that, although an examination of the conditions 
under which the cotton plant may be cultivated with success is one 
of much interest both in a scientific and economic point of view, yet it 
is strange that science, botanical, chemical, and climatological, should 
as yet have supplied so little information with respect to this plant, 
the most important source of the clothing of man. That, while other 
cultivated species, many of them of far less general value, have been 
the objects of careful experimental research—their botanical relation 
and improvement by hybridization settled—the character and extent 
of their demands for atmospheric and mineral food ascertained—the 
soils upon which they thrive or fail analysed—the climatal conditions 
which favour or impede their growth observed, the culture of cotton 
under favourable circumstances has, as an art , been advanced in one 
great locality almost to perfection, but without the scientific princi¬ 
ples upon which the art is based, and by the application of which 
alone success or failure in any new attempts elsewhere and under new 
conditions can be predicted. He shows that the immediate cause of 
this neglect of the science of cotton-culture has been the facility with 
which the vast and growing demand of the world for cotton has been 
met by the vast surface of fertile and virgin soil and other favour¬ 
able conditions of the southern states of North America, yielding 
wealth to the planter too readily to incite him to inquire much as 
to the conditions of his success. 

Although much virgin soil remains in the southern states un¬ 
touched by the cotton-planter, the author states that it needs but 
slight knowledge of the country to discover the vast extent of “ worn- 
out” cotton fields already existing even in the most recently settled 
states, or to predict a time when the growing demands for the 
staple must compel, there and elsewhere, the attention of the eco¬ 
nomist to the scientific aspects of the problem of cotton-cultivation. 
To fix with exactness the conditions under which the cotton plant 



342 


thrives, how far it can be brought to bear unfavourable circumstances, 
and by what means the latter may be modified to suit its require¬ 
ments,—such are the “fruit-bearing” objects of the author’s re¬ 
searches ; he remarks, however, that in the purely scientific aspect 
of his subject it is difficult to overrate the interest that attaches to 
every question touching the sure production of a material that, in its 
husbandry, manufacture, and consumption, closely concerns so im¬ 
mense a proportion of the human race. In the present paper, that 
branch of the subject which relates to the soil is taken up. 

The author in commencing gives a careful summary of all such 
experiments on American cotton soils as have been recorded prior to 
his own labours. These are not numerous. 

The second chapter describes, by the aid of a large geological and 
climatological map, the precise geographical boundaries of the regions 
of American cotton-culture, the geological or agronomic, climatal, 
and meteorological and general superficial conditions of these great 
surfaces, and the relations of each of these to the growth and culture 
of the several varieties or staples, such as “ Sea Island” or “long 
staple,” and “upland” or “short staple,” &c. The latter sort, con¬ 
stituting the vast bulk of the crop, and bearing, in 1858, the ratio of 
eleven hundred and six and a half millions to only about twelve 
million pounds of the “Sea Island,” the author deems worthy of 
prior investigation. In the first instance, limiting himself to this, he 
discusses carefully in his third and fourth chapters, the choice of 
district from which the most typical and important soils for examina¬ 
tion should be collected, and decides upon the selection of “ fair nor¬ 
mal specimens of prairie soil ” and its underlying subsoil, and to exa¬ 
mine them “ as minutely and accurately as possible,” believing that 
thus a clue would be more readily found to the causes of fertility as 
dependent on soil (for which this region is remarkable), than by a 
less careful examination of many specimens from this or that locality 
over so vast a surface. This method, without teaching all that we 
may want to know, is certain most readily to show us the right direc¬ 
tion in which to push further inquiry. Seven specimens of soil and 
subsoil were finally selected for comparison and analysis, mainly 
from that class of “prairie land” known as “canebrake land,” in 
Marengo, County Alabama, in lat. 32° 35 f N., long. 87° 36' W., the 
points being marked upon the map accompanying the paper. 



343 


The characteristics of this very peculiar soil, its prevailing weeds, 
and most important Silva and Flora, its average depth, nature of 
surface, effects upon it of rain and of drought, the form of its water¬ 
courses, and general conditions affecting the cotton plant are carefully 
described, and their bearings on the subject discussed. The exami¬ 
nation of these soils was twofold—physical or chemico-physical, 
and purely chemical or analytical. The methods employed in each 
are detailed; and in the former, those of Schiibler and of Schulze, 
with modifications by the author, were principally employed, atten¬ 
tion being also given to the methods and results of Liebig’s recent 
experiments, and those of others, on the power of withdrawal by soils 
of saline and other substances from their solutions. The external 
characters of the soils examined are then described; the real or 
true specific gravity, and the weight of a given volume in 
known conditions of moisture and dryness—the contraction in volume 
on drying from a determinate extreme of wetness—the cohesion of 
the soil, or adhesion of its particles (in known conditions as to 
moisture) to each other, are all determined, the last by a method 
believed new. The adhesion of these soils to the surfaces of iron 
implements, as ploughshares, hoes, &c., was ascertained in the state 
of" maximum moisture,” as proposed by Schiibler, of whose method, 
however, the author expresses some disapproval. 

The next physical condition determined is the absorption of heat 
from the sun’s rays, with tabulated results, both for the absolute 
maximum temperature attained ; and the rate at which the increment 
takes place. The results indicate the importance of noting the latter, 
and prove that the statements of Malaguti and Durocher, in opposi¬ 
tion to Schiibler, that mineral composition has a more important 
influence than colour upon the thermo-absorptive capacity, and that 
of sand is greater than that of clay, must be accepted with consider¬ 
able limitations. Conversely, the author has determined the relative 
retentive powers of these soils for heat, having intimate relations 
with the rate at which they lose heat after the sun has become ab¬ 
sent, and tabulated his results, which differ considerably, as he 
notices, from those of Schiibler in analogous cases,—the discrepan¬ 
cies remaining after repetition, by the author, of his own experi¬ 
ments. He points out some of the probable causes of this. 

He then proceeds to the power of absorption and retention of 



344 


water, with tabulated results. The extreme tenacity with which the 
best cotton soils retain a very large proportion of their water of satura¬ 
tion after lengthened periods of exposure to dry air is remarkable, 
and the importance of this in the hot climate of cotton-culture 
is pointed out. In immediate connexion with this point, their per¬ 
meability, or the rate at which water percolates through these various 
soils was ascertained, the relations of which to partial rain or dews, 
and to the desiccation of one mass and species of land in times of 
drought by others adjoining are important and obvious; and again, 
in the same relations, the capillarity, or rate at which water is 
drawn through and upwards in the soils from deep moisture below, 
was determined. In this part of his labours the author considers 
with some exactness the nature and measures of the true capillary 
power of soils, refers to the recent interesting researches of Jamin on 
the capillarity of porous bodies, and describes some new and peculiar 
apparatus by which he has determined this for the soils in question, 
the results being given in several tables. These indicate strikingly 
one of the remarkable properties due to the extremely fine state of 
division of these “best cotton soils, 33 on which, in part, their fertility 
depends, viz. that they draw up moisture from the subsoil with im¬ 
mense power, and therefore from great depths, but yet do so with 
great slowness; so that in a torrid climate the subsuperficial supply 
of water fluctuates but little, and is slowly supplied and long in 
being exhausted in drought; while other soils pump it up rapidly, 
and as rapidly waste it. This property becomes more important 
as the distribution of rain, both in season and in space, is more un¬ 
equal naturally. 

The hygroscopic power, or power of absorbing aqueous vapour 
from the atmosphere, is next experimented upon, and the results are 
tabulated, and also represented graphically by curves, as are several 
of the other numerical results. 

The author then proceeds to the highly important subject of the 
absorptive power of the soils for gases directly or indirectly affecting 
the growth of plants. 

Tabulating the results for oxygen, carbonic acid, and ammonia, 

* the most striking result here exhibited is the prodigious power of 
absorbing ammonia possessed by the dry canebrake soils. This 
soil condenses 52 volumes (equal to its own) of ammonia, and its 



345 


subsoil 64 volumes. It will be remembered that De Saussure found 
that the most impalpable powder of boxwood charcoal only ab¬ 
sorbed 90 volumes equal to itself. Another cause of the extreme 
fertility of these soils is thus brought into evidence. 

From this the experimenter proceeds to the determination of ab¬ 
sorption or withdrawal by the soils of inorganic substances in con¬ 
tact with them, and in solution; experimenting on ammonia, chlo¬ 
ride of ammonium, sulphate of ammonia, nitrate of potass, phosphate 
of soda and silicate of potass, and determining the proportions 
both of acid and of base withdrawn. The methods by which he 
proceeded are described with reference to each of the above salts. 
In several cases the acids and bases are not absorbed in the propor¬ 
tions in which they constitute the salts. These very curious and 
suggestive results are graphically given as well as tabulated. The 
labours of various -pther chemists in this direction are referred to 
and discussed in reference to those of the author. 

Professor Mallet then refers to what he denominates the mechanical 
analysis of the soil, pointing out the necessity, in all agronomic deter¬ 
minations, of finding, by methods admitting of comparison with 
distant soils, the texture, coarseness, or fineness, &c. of the constituent 
particles. These results are given in eight consecutive comparable 
tables. Each soil was separated into six solid portions and the 
remaining water making up its total weight—viz. into the material 
passing through sieves respectively offering 36, 100, 400, and 1600 
meshes to the square inch, and into suspended matter of two de¬ 
cantations. 

The proportion of impalpable material is very remarkable, amount¬ 
ing in the best soils to more than 70 per cent, of the whole. Not a 
pebble or particle almost, exceeding ^th of an inch in diameter, is 
to be found in those best cotton soils whose comminuted state per¬ 
mits the free pushing out of root-fibres in all directions. 

The purely chemical part of the investigation is then proceeded 
with. The methods employed for the chemical analysis of the soils 
are given under the heads of water, organic matter, inorganic mat¬ 
ter soluble in water, inorganic matter soluble in hydrochloric acid, 
inorganic matter decomposable by strong sulphuric acid, and that 
not acted on by this acid. And the results follow in eight tabular 
statements, but are of too detailed a character to be brought into 

2 c 


VOL. XI. 



346 


an abstract, and without such the discussion that succeeds would not 
be sufficiently intelligible to be useful. It may be interesting to 
state that measurements have shown that the average mass of soil 
interpenetrated by the roots of each cotton plant in Alabama is 
about 5 cubic feet; within this bulk of soil a sufficient amount of 
inorganic constituents for the plant must be found naturally, or be 
artificially transferred to it. 

Professor Mallet compares his results with the analyses of Indian 
soils made by Dr. Forbes Watson, pointing out both similarities and 
differences. 

In concluding his analyses of the soils and subsoils, the author 
gives also one of the so-called “ Rotten Limestone,” and of the 
“ Bored Rock,” both calcareous rocks of a very friable character that 
underlie the Cane Brake soils. He concludes his elaborate research 
with some general deductions from his examination of Alabama cotton 
soils, and with an appendix, in which he describes the mechanical or 
agricultural methods employed in that State in the treatment of the 
same. These are given as follows in the words of the paper. 

General Deductions from the examination of Alabama Cotton-soil, 

In order to draw any useful conclusions from experiments such as 
the above, upon a soil, the plant to be cultivated must be noticed, as 
well as some of the modes in which it is affected by climate. 

A few remarks upon the cotton plant and its climatal peculiarities 
must therefore be made here in anticipation of a future part of the 
paper. 

Annual cotton, as cultivated in America, is a plant which attains 
its principal growth in about four months, although it continues to 
develope seed and fibre for a much longer period. 

The extent to which its roots penetrate the soil has been noticed 
above, and from this some imperfect idea may be formed of the power 
which it possesses of drawing upon the earth for nourishment, although 
no measure is thereby obtained, I think, of the capacity of the earth 
to yield nourishment*, as is shown by the experiments upon capilla¬ 
rity and saline absorption. Nor, indeed, do we even obtain any cer- 

* On the assumption of Liebig—that mineral food is taken up only by direct 
contact with the roots—the surface exposed by the latter does become a measure 
of the capacity of any particular soil to yield such nourishment. 



347 


tain knowledge of the power with which the plant takes up its food 
from the soil, unless, by microscopic examination, and by experiments 
such as those of Hales, some estimate be formed of the combined 
effects of capillary and osmotic action in drawing up liquids of various 
composition. 

The special mineral food required by the cotton plant, and the 
amount of this food, remain to be examined by analyses of the ash, 
which will form another part of the investigation. Some statements 
with regard to the nature of the mineral constituents have been made, 
drawn from the results of Dr. Jackson’s analyses, and all these sub¬ 
stances needed by the plant have been seen to exist in the soil. As 
to the extent to which they are withdrawn from the soil by cultiva¬ 
tion, it may be remarked generally that cotton is by no means an 
exhausting crop under proper management. 

The great mass of the plant—root, stem, branches, leaves, and 
emptied boles—remains upon the field, and is ploughed into the soil, 
which is enriched by the rapid decay of the organic matter. Nothing 
is removed except the fibre and seed, and a large proportion, if not 
the whole of the latter, is by judicious planters * returned to the 
land; cotton seed is in fact almost the only material used as manure 
in the cotton region of America; a large amount is added to the 
soil by the ordinary mode of planting, the seed being thickly strewn 
by handfulls in a continuous row, upon which, after thinning, but a 
few plants are allowed to remain. The cotton fibre, which constitutes 
the saleable product, and is absolutely carried off from the land, must 
be looked upon as a very light crop ; a bale of 400 or 500 lbs. to 
the acre is sometimes obtained under favourable circumstances, but 
this is much above the average for upland cotton. The fibre yields 
1 or 1 \ per cent, of ash, so that at the most 7| lbs. of mineral matter 
per acre will be removed from the soil annually. 

According to Johnston (Lectures on Agricultural Chemistry, p. 216), 
a crop of wheat of 25 bushels to the acre removes from the soil, 
in the grain alone , about 17*65 lbs. of mineral matter; a crop of 
barley of 38 bushels carries off, in the grain , 46*98 lbs.; a crop of 
oats of 50 bushels, in the grain , 58*05 lbs. According to Liebig 

* The practice of selling cotton-seed from the plantation is one to be strongly 
deprecated; it is beginning to he common in some districts, owing to the increasing 
manufacture of cotton-seed oil and exportation of the cotton seed-cake to Europe. 

2 c 2 



348 


(Letters on Modern Agriculture, p. 41), an average crop of potatoes 
removes from each acre about 163 lbs. of mineral matter; and one 
of beet about 458 lbs. (leaves included). 

With respect to climate, cotton needs a high summer temperature ; 
although not properly a tropical plant, it produces fibre in diminished 
quantity, though of improved quality, when removed from a southern 
locality to one further north; it never seems to he directly injured 
hy the most intense midday heat; when other crops, including even 
Indian corn, are drooping under a blazing sun, the large succulent¬ 
looking leaves of a cotton-field will but seem to enjoy the congenial 
temperature. As is said hy the writer of a pamphlet published by 
the Cotton Supply Association—■“ cotton is decidedly a sun-plant .” 

The proper supply of moisture is a point of at least equal import¬ 
ance with temperature, and here appears undoubtedly to lie the main 
difficulty hitherto experienced in attempts to extend the culture of 
cotton into new regions. Published statements differ greatly as to 
the effect of moisture or dryness upon the plant, some writers saying 
that a wet season is ruinous to cotton and that drainage is of the first 
importance; while others, especially many of those treating of cul¬ 
tivation in India, insist that irrigation is more necessary than anything 
else. Dr. Royle* well says, “such terms as moisture and dryness 
are so entirely comparative, that in one country we hear the cotton 
plant described as one requiring moisture, and in another we find it 
stated that no plant requires so little ; the fact being, that the plant 
can hear both great heat and considerable want of water, provided it 
is growing in a not over-dry atmosphere.” 

The last sentence states an important part of the truth, but, I 
think, not the whole; it draws a distinction between two forms in 
which moisture may be supplied to the growing plant, whereas it 
would seem that four should be separately noticed. 

1°. The atmosphere may contain a greater or less amount of water 
in the state of vapour, up to the point of so-called saturation. 

2°. The atmosphere may be supersaturated, or in other words, 
precipitation of liquid water, as rain, &c., may take place from it. 

3°. The soil may contain a greater or less amount of water inti¬ 
mately united with it, whether by adhesion or chemical combination 

* Dr. J. Forbes Royle ‘ On the Culture and Commerce of Cotton in India and 
elsewhere/ p. 223. 



349 


—such water as is rapidly absorbed from the air by artificially dried 
soil, and can afterwards be expelled only by the application of a high 
temperature. This water does not render the soil moist to the touch. 
It can accumulate in a particular soil to a certain extent only, and 
this limit may be called the point of saturation of the soil. 

4°. The soil may be supersaturated, that is to say, liquid water, 
evident to the senses as such, may mix with the earth and render it, 
in the common sense of the term, moist or wet. 

Now it would seem that the larger the relative amount of water in 
the 1st and 3rd of these forms taken up by the cotton plant, and 
the smaller the quantity received in the 2nd and 4th forms (at least 
during the greater part of its period of growth), the more favourable 
will be the result. 

In water-soaked soil, i. e, holding water in the 4th condition men¬ 
tioned, cotton will not thrive. The following statements * are borne 
out by the general experience of planters. “The tap-root of the 

cotton plant will not strike down into wet soil.On wet land 

the cotton plant grows small, looks sickly, or scalds in the hot sun, 
and bears but little raw cotton, and it takes twice the labour to cul¬ 
tivate it, as the grass usually grows the faster, and is much more dif¬ 
ficult to kill out. 55 Such soil will obviously be benefited by draining. 
On the other hand, the state of things demanding artificial irrigation 
—very necessary probably in some parts of India—would seem to be 
simply the absence of water in any one of the three other conditions 
noticed. 

In the early stages of growth the plant receives a moderate supply 
of rain, i. e. water in the 2nd condition named, with advantage; 
but even then heavy rains are very injurious, and later in the season 
they are absolutely destructive; the bolls do not open, but fall off, or 
rot upon the branches—a surface growth of grass and weeds accu¬ 
mulates so rapidly as to choke the crop—the boll worm and other 
destructive insects make their appearance—and the cotton from bolls 
already open hangs out in trailing locks, draggled, dirty, and matted 
together. Dry years are emphatically those of the largest and best 
crops. 

Yet, like all other plants, cotton must be supplied with moisture; 

* From the pamphlet * On the Cultivation of Orleans Staple Cotton/ published 
by the Manchester Cotton Supply Association, p. 14. 




3bQ 


tbis even seems to be needed in considerable quantity, judging from 
tbe extensive leaf-surface from which evaporation is carried on. 
Aqueous vapour in the air, as suggested by Dr. Royle, and abundant 
hygroscopic moisture in the soil itself, as I would add, seem to be 
decidedly the sources from which this requirement is to be met. 

The great advantage derivable from a soil of high capacity for ab¬ 
sorbing and retaining moisture will be, that it will enable the plant 
to withstand vicissitudes of weather and season; in damp weather 
hygroscopic water will be condensed, to be stored up in the retentive 
soil until required in the midst of drought ; in August or September, 
when seed and fibre are to be formed, and when therefore diminished 
leaf-activity is desirable, the roots will gradually draw up a supply of 
this water, limited*, but sufficient to maintain healthy life. 

These remarks no doubt apply also to the absorption of gases, and 
of mineral matter withdrawn from solution, as has been noticed in a 
previous part of the paper. The power of steadily accumulating and 
gradually dispersing seems to be one of the well-marked and beau¬ 
tiful provisions of tbe “ economy of nature ” 

The soil of tbe prairie region of central Alabama fulfils the above 
conditions admirably, and to this fact should, I believe, be in large 
measure attributed the success with which cotton is cultivated upon it. 

To sum up the results of the examination of this fertile cotton soil, 
it is shown to be a stiff aluminous clay, containing moderate amounts 
of organic matter and of the mineral substances needed by the plant 
as food-—of great uniformity, and in an exceedingly fine state of 
division—above all, possessing a very high capacity for absorbing and 
retaining heat, moisture, gases, and soluble mineral matter. 

Appendix. 

Mechanical Treatment of Cotton-soil, as practised in Alabama . 

In order to complete the subject of Alabama cotton-soil, it seems 
desirable that to the preceding results should be added a brief state- 

* The porous chalky substance referred to as “ rotten limestone,” which under¬ 
lies the soil of the cane-brake, has itself very similar capillary and absorptive 
power; it is penetrated by sandy strata, through which water can readily flow, 
and hence it is not at all inconceivable that supplies of moisture may even through 
this be drawn up from the depth of 20 or 30 feet, at which the first sandy bed is 
often met, 



351 


merit of the way in which this soil is usually cultivated, which may 
easily be done in a few paragraphs. 

As early in the winter as the weather is favourable and the con¬ 
dition of the ground suitable, i. e. when not too wet*, the preparation 
for the crop commences by “ bedding ” the land. This is done by 
running a narrow plough called a “ bull-tongue ” at regular intervals 
across the field, the common distance being four feet between the 
rows. In very rich alluvial land the distance is sometimes five or 
even six feet, and in thin poor land not more than three feet. Upon 
the furrow thus produced the ridge or “bed” is made by ploughing 
to it on either side with a turning plough, called a “ Carey” plough, 
drawn by two mules or horses, until the space between the rows has 
been ploughed out. The whole field is in this way thrown into 
ridges, which should run horizontally round any elevated portions 
of the plantation, so that heavy rains may not wash away the soil. 

When the time for planting arrives—about the beginning of April— 
a furrow is run along the top of each ridge by a narrow plough, and 
in this furrow the cotton seed is pretty thickly strewn by handfulls 
as the labourer goes along the row. It is then covered with earth 
by a heavy wooden block, which a mule or horse draws along, so as 
not only to cover up the seed, but to press the earth firmly upon it. 

If the weather be favourable for the germination of the seed, it 
comes up in ten days or a fortnight, and soon afterwards the culti¬ 
vation commences by thinning out the cotton with hoes, so as to leave 
but a few stalks together at intervals of eight or ten inches, removing 
also any grass or weeds which may have grown with the cotton. 
The space between the rows is at the same time ploughed to make 
the earth light and mellow, and to destroy grass and weeds. Great 
skill is shown by trained negroes in the use of the plough and hoe,— 
the former is often run within two inches of the cotton, and the latter 
used to cut out a weed within an inch or even half an inch, without 
in either case injuring the cotton itself. The process of working 
the crop with plough and hoe is continued at intervals of three 
weeks, and at each time of thus going over the field the cotton is 
thinned out, until it is brought to a “ stand/’ that is, reduced to single 

* The peculiar condition of the “ cane-brake ” soil (to which the above remarks 
apply) intermediate between a dry and a thoroughly wet slate, in which alone 
ploughing can well be carried on, has been noticed in an earlier part of the paper. 



352 


stalks 12 or 18 inches apart upon the rows. Early in July the plant 
has usually acquired sufficient size to shade the ground and prevent 
the further growth of grass, and the crop is then “ laid by.” It is 
of the first importance that the land should have been kept perfectly 
clear of weeds up to this time, and in a hot climate the task is often 
a difficult one. 

Simultaneously with the cultivation of cotton, the cultivation of 
Indian corn, sweet potatoes, &c., proceeds, in order to furnish food 
for the negroes of the plantation, for the mules or other draught 
animals, and for a sufficient number of hogs to yield meat for the 
labourers. 

In middle Alabama the cotton plant usually commences flowering 
early in June, and continues to bloom until frost kills it, bolls con¬ 
tinuing therefore to form during several months. The earliest bolls 
open, in ordinary years, from the 10th to the 15th of August, 
when the “ picking ” season commences. This lasts until the cotton 
is all gathered—until January or even February, if a full crop be 
made. The bolls continue gradually to open long after frost has 
prevented the formation of any more. In picking the cotton from 
the boll, surprising manual dexterity is shown by negroes accustomed 
to the task from early youth. 

The seed cotton, as it is collected into large baskets by the pickers, 
is carried to the “ gin-house” of the plantation, and “ginned;” and 
when enough of the clean fibre has accumulated, a day or two is de¬ 
voted by a part of the hands to pressing it with the large wooden 
“ screw ” into bales ready for shipment by river to the sea-port. 

XI. “ Account of Experiments made at Holyhead (North Wales) 
upon the Transit-Velocity of Waves through the Local Rock 
Formations.” By Robert Mallet, Esq., C.E., F.R.S. 
Received June 18, 1861. 

(Abstract.) 

These experiments were made by the author at the joint request 
of the Royal Society and of the British Association for the Advance¬ 
ment of Science, aided by grants from each of those bodies. 

Their object was to ascertain the transit rate or velocity of pro¬ 
pagation of waves of elastic compression, analogous to those of na-