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AN
INTRODUCTORY MANUAL
FOR SUGAR GROWERS
BY
PRANGCIS. WAITS, .F.€:S. 09 L€:
ASSOC. MASON COLL., BIRMINGHAM, AND GOVERNMENT CHEMIST, ANTIGUA, W. I,
LONDON LONGMANS, GREEN, AND CO.
AND NEW YORK: 15 EAST 16th STREET 1893
All rights reserved
COPYRIGHT, 1892, BY
LONGMANS, GREEN, AND CO.
TROW DIRECTORY PRINTING AND BOOKBINDING COMPANY NEW YORK
-_ -
“ 6F
PREFACE,
_ AN experience of some years in the West Indies has led me to see the necessity for some simple hand-book for the use of those engaged in the sugar industry—a hand-book containing an outline of the principles of agriculture based on modern scientific discoveries, and also an outline of the principles underlying the manufacture of sugar.
An attempt is made in the following pages to col- lect together in as simple a manner as possible a series of observations on these points, in the hope that they will serve as a starting-point for young overseers about to begin their training in the sugar- fields and boiling-houses, and also, perhaps, as a means of rendering more easy and accessible to older men the information to be obtained from larger works and from scattered papers and pam- phlets.
One difficulty which sugar growers experience is that writers on agriculture have rarely written upon their special subject, but have treated of the methods and productions of temperate climates ; hence there has often been a doubt as to the extent to which the writers’ remarks could be with
vi PREFACE.
safety applied to a tropical plant and under tropical conditions.
A sugar literature is now springing up, and it is hoped that this little book may be one of a series of hand-books, each dealing in a more exhaustive manner than in the present case with some one branch of the sugar industry. If a number of com- petent writers could be induced to contribute to this end, such a course would do much to give accuracy and precision in the place of the old “rule of thumb.”
FRANCIS WATTS.
GOVERNMENT LABORATORY, ANTIGUA, W. L, November, 1892.
PABLE: ‘OF CONTENTS:
PAGE LUSTER Ue > Say a aS Oe Ses ei ye Cy 5, PSP OW CONTENTS -. --< sc « 3s. # wlio oo 3 oo AH Pie CuLLUSTRATIONS. ele. 20 oo 3. SC Oa 2 Ee
CHAPTER I.
Introduction.—Chemical Elements and Symbols.—Cells, Tis- sues, and Fibro-vascular Bundles.—Structure and Func- tion of Roots, Stems, and- Leaves .-. ./:...°. . 1-14
CHAPTER II.
Origin of Soil, Clay, Chalk or Marl, Sand.—Fertile Soil.— Conditions Influencing Fertility.—‘‘ Condition or Heart.” —Function of Vegetable Matter in the Soil.—Moisture.— Mineral Plant-food. — Analysis of Soils. — Nitrogenous Plant - food. — Nitrification. — Leguminous Crops and Nitrogen.—Root-nodules.—Retention of Plant-foods by Soils.—Drainage - . 15-39
CHAPTER III.
Sugar-cane. — Preparation of Land, Planting, Manuring, Weeding.—Cutting Cane.—Methods of Dealing with the rash: —Moglding.. 5 6 <0 ie ek ew 40-50
CHAPTER IV.
Manures.—Farm-yard or Pen Manures, their Function and Use.—Management of Pen Manure.—Open and Covered Pens.—Green Dressing.—Chemical Manures.—Potash, Phosphates, Mineral Phosphates, Superphosphates, Basic Slag or Thomas Phosphate. — Nitrogenous Manures.— Pail aceler. Prone” a: “s)he. Ses coe oe ee, ee
vill CONTENTS.
CHAPTER V. siee Cane-mills. — Three-roller Mill. — Fletcher-Le Blanc Four- | roller Mill—Mirlees’ Four-roller Mill.—Skegels’ Mill.— De Mornay Mill.—Hydraulic Attachment, etc.—Double Crushing.—Maceration.—Diffusion . .. . . . 7-84
CHAPTER VI.
Cane-juice. — Composition. — Tempering. — Use of Lime. — Phenol-phthalein Test for Lime.—Clarifying. —Forma- tion of Scum.—Treatment of Scum.—Filter Presses. — Composition of Filter-press Cake.—Uses of the Cake.— Watavie: Cakes 2s oti lw Ge 2 aes oe a oe
CHAPTER VIL.
Manufacture of Sugar. — Inversion. — Open-fire Process, — Steam Pans. — Muscovado Sugar. — Vacuum Pan. — Method of Operating. — Triple Effect. — Centrifugals. —Production of High-class Sugars.—Use of Sulphur.— Carbonation.—Phosphoric-acid Process.—Animal Char- COAL MMe Fale ihe bode: | «2st b iar ie ae: ae as ae eee
CHAPTER VIII. Hydrometers or Saccharometers, and their Use . . . 117-121
CHAPTER IX. ‘Molasses.—Production, Composition, and Uses.—Recovery of ugar from Molasses. -.... 2 ...v: =< | = . -elee—iee CHAPTER X.
Fermentation.—Nature of Ferments.—Conversion of Cane Sugar into Alecohol.—Setting up Wash.—Yield of Alco- hol.— Distillation.—Forms of Stills . ... . . 127-136
TABLE OF TEMPERATURE OF STEAM UNDER VARIOUS PRESSURES .s. -02: ae Ve ee 2 Se eee
LisT OF ELEMENTS, WITH THEIR SYMBOLS AND Com- BINTNG: WEIGHED (5 2) 0 ak, fae et or 7 ee
TABLE OF DENSITIES, ETC., OF SACCHARINE SOLUTIONS, 139, 140 ERDEX 4 - gos 604, 20 2 a)” oS) be eee eee oe
FIia.
Lisl! OF ILLUSTRATIONS:
PAGE
. Fibro-vascular Bundles in Sugar-cane, Longitudinal and
EREARSVCTSE SECHIONS 0 Acts oe aid Coe ae eee ee ak ern
. Fibro-vascular Bundles in pee showing Fibres
Bnd VESSEIS 2, is. Us: @s SOS ARAM <2. ool SERRE:
. Rootlet, with Root-hairs and ee Pe es ed 3) . Transverse Section of Sugar-cane Leaf ...... ii . Epidermis of Sugar-cane Leaf, with Stomata . . . . 11 mmechonor Hogt-nodule. 3 (e4 .. 2 2. Ba) = 29
. Diagram of Pipes and Jointsin Tile Drain . . . . . 87 . Diagram of Three-roller Mill. . . . Be okra dO) . Diagram of Fletcher-Le Blanc Four-roller Mill. . . . 6 . Diagram of Mirlees' Four-roller Mill . . . .... 77
= wiasram of De Mornay Mill .*.° .- 2.2 «7. 3 . 98 menmemplo Of Hydraulic Press). ee es eG. ar ee 09 . Diagram of Hydraulic Attachment toCane-mill . . . 79 poliarram, of Diftusion: Battery ..:. +... %s 0. : «... 2. 88
. Diagram of Curves, Illustrating the Increase of Glucose
with Increasing Concentration in Various Processes of pucar Manntactare 3 1 ot pn a ee ee! = 108
moideram of Vacuum Pan 0. -.° i. 4) s,s ee 2 AOD - Diagram of Triple-effect Apparatus. . .°. . » «.-. 109
. Beaumé’s Hydrometer or Saccharometer . . . . . . 118 MEAS PAANE 6) 50 58 ak aes Sow an a Bele. eriseram.of Continuous Still... 2 » .« % Ge «'. «feb
MANUAL FOR SUGAR GROWERS.
CHAPTER I.
Introduction.—Chemical Elements and Symbols.—Cells, Tissues, and Fibro-vascular Bundles.—Structure and Function of Roots, Stems, and Leaves.
N the study of agriculture an acquaintance with a number of sciences is necessary. Promi- nent among these are chemistry and botany, some knowledge of chemistry being necessary in order that the changes taking place in soils under tillage and cropping may be understood and the require- ments of the crops economically supplied. The sugar grower, being also as a rule a sugar manu- facturer, requires to know some chemical facts in order that he may understand the changes to which sugar is liable, and how to promote advantageous ones while preventing those which are harmful. A knowledge of the fundamental principles of plant life and nutrition is quite invaluable to all engaged in agriculture. One of the most important facts which chemistry has taught us is the indestructibility of matter: nothing is created, nothing is destroyed in the con-
2 MANUAL FOR SUGAR GROWERS.
tinuous changes which are observed daily, these changes being simply the result of the re-arrange- ment of the same matter over and over again in the ever-varying forms existing on the earth.
Another important fact is the knowledge that all the things in the world result from the combination of two or more of some sixty-five simple substances, or, as chemists call them, elements. These elements are each composed of one kind of matter only, “and out of each no two or more essentially differing substances can be obtained.”
A list of the elements, with their combining weights, is given in the table on page 138.
Some of these elements are extremely rare sub- stances, while others exist in enormous quantities. The following are those which enter into combina- tion to form all the various parts of plants and plant products :
Hydrogen. Potassium. Sodium. Oxygen. Calcium. - Manganese. Carbon. Magnesium. Silicon. Nitrogen. Tron. Chlorine. Sulphur. Phosphorus.
From this it follows that if some particular ele- ment be wanted—say, for instance, potassium—to supply plant-food in a soil deficient in that element, then something containing potassium must be used to supply the defect, for out of no combination of substances can potassium be created. It must ex- ist in the substance employed, for matter cannot
MANUAL FOR SUGAR GROWERS. 3
be created or destroyed, nor can the elements be changed one into the other; potassium is always potassium, nitrogen always nitrogen, and so on, though the substances which can be obtained by combining these elements in various ways are end- less in number.
For the sake of convenience it is customary to represent each element by means of a symbol, usu- ally the first letter of its name, and this symbol also indicates a definite quantity of the element, the equivalent or combining weight. Thus the symbol C indicates carbon, but it also stands for twelve parts by weight of carbon. (See equivalent weights in table.) Again, the symbols H and O stand for one part by weight of hydrogen and sixteen of oxygen respectively. Compounds are formed by the union of two or more elements and are represented sym- bolically by writing the symbols of the constituent elements together, the quantity of any particular element present In a compound being indicated by a small figure placed a little below and to the right of the element in question: thus, water is found by experiment to be composed of the elements oxygen and hydrogen, and also to contain two parts by weight of hydrogen to sixteen parts by weight of
oxygen. ‘These facts are represented by the sym- Hot FF O.*
* For a full explanation of this subject any good elementary text-book should be consulted, this outline being merely given in order that the chemical formule, etc., necessarily employed may be to some extent understood by those having no chemical knowledge.
+ MANUAL FOR SUGAR GROWERS.
All vegetable structures are built up of minute cells of very various shape. The simplest cell is a chamber whose walls are thin and usually has fluid contents : these cells joined together form a tissue, and aggregates of different tissues form the root, stem, and leaves, the three portions of which plants consist. In order to study these cells the microscope must be em- ployed. A thin slice of the soft part of the sugar-cane, cut length- wise, presents the appearance shown in Fig. 1, where it will be seen that the greater portion of the stem is composed of cells
Fie. 1. — Fibro-vascular : bundles in sugar-cane; Which are of about the same
, longitudinal; oe eee length as breadth, with thin walls,
transverse section. : and having, as seen in section, a
honeycomb -like appearance ; these are usually spoken of as cells—ordinary cells, without any qualifying term. Travers- ing this cellular tissue will be seen a number of thread-like cells running parallel with each other ; a closer inspection, on magnifying these threads to @ 4... o yibro-vasenlar bum ereater degree, as seen dn, Fis?) tesmeeaseae 2, shows that the thread-like
cells are not all alike. Some are tubes with thin walls, having rings arranged on the inside of the
MANUAL FOR SUGAR GROWERS. 5.
tube, in others a fine thread is wound in a spiral throughout the length of the tube, while others pre- sent the appearance of being perforated with minute holes. These thin-walled long cells are known as vessels, and are named, according to the markings on their walls, annular or ringed vessels, spiral ves- sels, dotted vessels, etc. Lying round these vessels just described will be seen a number of long thread- like cells, the walls of which are thicker and display no particular marking; these cells are generally of smaller diameter than the vessels, and the walls are considerably thickened ; they are commonly spoken of as fibres or fibrous cells: hence the collection of fibres and vessels which has been described is gen- erally known as a fibro-vascular bundle, and these bundles will be found traversing the cellular tissue in all parts of the plant.
When vegetable tissues are burned one portion disappears in the form of gas or vapour, while a small portion remains behind as ash; the portion which disappears is composed of the elements carbon, hy- drogen, oxygen, nitrogen, with some of the sulphur ; the ash contains the remaining elements mentioned in the list on page 2; these are combined with oxy- gen, and are generally spoken of as mineral constit- uents, or sometimes as ash constituents. These facts are familiar to planters from burning megass.
The walls of the cells already described are com- posed of carbon, hydrogen, and oxygen arranged in the following proportions, C,H,,O,,* forming a
* Inspection will show that this substance is composed of six equivalents of carbon with five equivalents of water. These com-
6 MANUAL FOR SUGAR GROWERS.
substance known as cellulose. In the interior of each living cell is a little mass of jelly-like sub- stance known as protoplasm ; this is a substance of the greatest importance, for it is the source of all the vital functions of the plant, which plant may be compared to a large barracks, each cell being a little room, the inhabitant of each room being the living protoplasm. All growth, all production of useful substances, depend on the life and changes taking place in the protoplasm. To support life and to maintain growth, food of course is necessary, so the protoplasmic contents of the cells must be fed. The food consists of mineral matter with nitrogen compounds brought up from the root, together with compounds containing much carbon obtained from the leaves. The functions of the roots and leaves will be shortly explained.
The usual method of propagating the sugar-cane is by planting short lengths of the stem or cane, the upper portion or top being usually selected for this purpose. When placed in moist soil a number of roots make their appearance from the double row of marks arranged just above each joint, and a new stem or cane grows from each bud, or eye.
The Root.—The sugar-cane has no main root, but like all grasses possesses a great number of fine rootlets; these spread to a great distance and to
pounds—in which hydrogen and oxygen exist in the same propor- tion as in water, namely, two equivalents of hydrogen to one of oxy- gen—are called carbo-hydrates. Cane-sugar, C:2H2.0;;, glucose, C.H.20¢, starch, C;Hi,0O;, and a vast number of other substances, are carbo hydrates.
_MANUAL FOR SUGAR GROWERS. 7
a considerable depth in suitable soil. The results would be of considerable interest and value if planters would make a series of observations on the range of the roots of the sugar-cane. The observa- tions of Mr. Henry Ling Roth are among the best known, and as the result of these it may be stated that in good soil the majority of the rootlets reach a depth of about two feet, a smaller number extend- ing even to four and five feet ; the lateral spread is from three to four feet. The author’s observations lead to the conclusion that in moderately well-tilled soil the roots grow downward until they reach the layer of soil but little disturbed by cultivation, and then spread laterally; so that the depth to which the roots descend in stiff soil depends on the depth of the tillage. If the extremities of the rootlets be examined they will be found to be very fine and tender and also to adhere closely to the particles of soil with which they come in contact. A closer in- -spection will show why this is. If examined with a magnifying-glass it will be seen that the fine rootlet, instead of being perfectly smooth, is, on the con- trary, clothed with a quantity of exceedingly deli- cate hair, but only for a short distance near the tip ; a short way back the hairs die off and the rootlet becomes smooth. These root-hairs are of interest, for it is by means of these that the plant absorbs moisture from the soil, and with the moisture the mineral plant-food which the soil supplies. If the extremity of the rootlet be examined it will be found to be clothed with a little cap or sheath, the use of which a moment’s consideration will render
8 MANUAL FOR SUGAR GROWERS.
evident: roots increase in length only at their ends, so that the end always consists of young and deli-
Fie. 3.—Rootlet, with root-hairs and root-cap.
cate cells which must be protected from injury while being thrust through the soil; the root-cap therefore affords protection to the delicate cells lying beneath it. The root at intervals throws out branches which from their earliest appearance are clothed with a root-cap, and root-hairs soon de- velop near the end. It will easily be seen why it is impossible for roots to lengthen except at their ex- tremities, for the root-branches imbedded in the soil would be torn off if the main root grew in length in the parts between their respective bases. *
*In taking up a rootlet for examination for root-hairs and root-cap, care must be taken in removing the soil, as these organs
are very delicate. The examination of rootlets growing under a flat stone is often highly satisfactory.
MANUAL FOR SUGAR GROWERS. )
Internally, the structure of the root may be briefly described as a mass of cellular tissue through the centre of which passes a heart or core composed of fibro-vascular bundles; the outside is covered with a layer of somewhat hardened cells forming a kind of bark.
The function of the root is twofold: it serves to fix the plant in the ground and also to absorb certain food-materials from the soil ; it is in doing this that the root-hairs play an important part. Only plant- food in a state of solution can enter the root, and that almost entirely through the root-hairs ; the older parts of the roots are almost destitute of absorbing power, and thus the extremities of the roots and rootlets are the only parts by which water with plant-food in solution can enter the plant,—a point to be borne in mind in the application of manures. The actual manner in which the root absorbs food is by the process known as osmose; this may be thus explained : When two fluids are separated from each other by a thin membrane, various substances dissolved in one of the fluids have the power of pass- ing through the membrane and thus appearing in the fluid on the other side, and this transfer of material will go on until the two fluids become of the same strength ; this may be experimentally illustrated by placing some strong solution of salt in a bladder, and, after tying it up securely, placing it for a few hours in a basin of water. On examining the water it will be found to be quite salt, the salt having passed through the bladder by the process of osmose. Only those substances which are capable of crystallising can
10 MANUAL FOR SUGAR GROWERS.
thus pass through the membrane ; they are distin- ouished as crystalloids. Now crystalline substances like gelatine, albumen, etc., cannot pass through, and are known as colloids. In the root the cells are the bladders, but with the solution of plant-food outside them; this is continually passing into the cells; the solution inside the cells is prevented from becoming of the same strength as that on the out- side, owing to the transfer of the plant-food by fur- ther osmose into other cells, till it is finally used in the process of growth.
The Leaf.—The leaf of the sugar-cane is about four feet long and two inches wide, tapering to a point; the leaf-stalk is developed into a sheath which closely embraces the stem. In internal structure the leaf is somewhat complicated ; the upper and under surfaces are covered with a skin or tissue called the epider- mis, which is composed of thin-walled flat cells hay- ing colourless contents ; between the upper and under epidermis is a mass of tissue the cells of which are filled with green contents ; running from end to end of the leaf are veins which are continuations of the fibro-vascular bundles of the stem. It will be seen in the drawing (Fig. 4) that these cells having green- coloured contents are not packed closely together, but that there are air-spaces between them, these air-spaces being very large in some places ; it will be noticed, too, that these air-spaces are in connection with the outer air by means of openings through the epidermis. If a little of the epidermis be stripped off and examined with the microscope, these open- ings may be readily distinguished ; the epidermis is
MANUAL FOR SUGAR GROWERS. OE
seen to consist of cells of somewhat irregular out- line, while the contents are colourless; at intervals
\
Seco aN
Fia. 4.—Transverse section of sugar-cane leaf (magnified); a, fibro-vascular bundles surrounded by (0) layer of cells containing chlorophyll; ¢, cells with colourless contents and air-cells ; d, epidermis ; e, stomata.
there will be seen pairs of cells having green con- tents ; these are crescent-shaped and lie with their points touching, so that there is a space between their opposing faces ; this space is the opening communi- cating with the interior air-spaces of the leaf ; these - erescent-shaped cells are known as guard-cells and the whole (guard-cells and aperture) is termed a stoma or mouth; by means of these stomata the in- terior cells of the leaf are in intimate contact with the at- mosphere. The atmosphere, which for the most part is composed of two gases, nitro- gen and oxygen, contains also a very small quantity of a gas known as carbonic acid or carbon dioxide, a substance composed of carbon and oxygen and having the composition represented by
Fie. 5.— Epidermis of leaf with stomata (magnified).
12 MANUAL FOR SUGAR GROWERS.
the formula CO,; this gas is produced whenever any organic substance is burned, thus every fire is a source of it ; it is present in the breath of all animals, a human being giving off about seven hundred pints every day, containing nearly eight ounces of carbon. This gas is fatal to animal life, and unless some means for its removal existed the whole atmosphere would become poisonous and animal life would cease. This gas is one of the most important plant-foods, for the cells possessing the green colouring matter above referred to have the power of decomposing it, retaining the carbon and returning the oxygen to the atmosphere. Animal and vegetable life are thus de- pendent on each other. ‘Two things are necessary for this process of plant-respiration: the green col- ouring matter (or chlorophyll, as it is called) and sunlight,—the process ceasing in the absence of light. This affords an explanation of the fact that plants become sickly if grown in rooms or dark places where they are not exposed to sufficient light.
It is from this source that all the carbon found in vegetable structures and products is obtained ; and what an important part of plant life, and how entirely the production of such substances as sugar depends on it, will be readily recognised if it be remembered that sugar contains nearly half its own weight of carbon.
The first substance produced by the plant from the carbon obtained by respiration is starch ; this is composed of carbon, oxygen, and hydrogen, hay- ing the formula C,H,,O,; the starch thus formed is quickly converted into other and soluble substances,
MANUAL FOR SUGAR GROWERS. 13
and conveyed down the leaf-stalk into the stem, to be used as food in the development of new tissues ; or stored up as a reserve food-supply in the form of sugar (in some plants as starch) to support growth when the daily supply of carbon is insufficient to meet some rapid development. An experiment shows the formation of starch in the leaf, the in- fluence of light on its production, and the fact of its removal. The leaf of a plant—such, for instance, as a rose—is placed in spirit for a short time until all the green colouring matter is removed and the leaf left white; the leaf is now washed with water and finally placed in water containing iodine in solution ; the effect of the iodine on the starch is to turn it blue, so that the leaf becomes of a blue-black colour from the presence of starch. A small plant is taken and excluded from sunlight for from twelve to twenty-four hours, by being covered with a_ box, or by other suitable means: if the leaves of this plant be treated in the manner described above, they will not be coloured blue by iodine, showing the absence of starch,—the starch formed during the period of exposure to sunlight being removed from the leaf by vital processes, and used as a food- material in the ordinary course of nutrition and erowth.
Another important function of the leaf is transpi- ration, or the evaporation of the superfluous water of the crude sap in the form of vapour. The quantity of water given off from the leaves of various crops has been made the subject of experiment; the amount transpired is found to be very great,—as much as two
-
14 MANUAL FOR SUGAR GROWERS.
or three thousand gallons per acre per day in some cases. The effect of this transpiration is to concen- trate the crude sap, thus promoting the absorption of water by the roots, and also causing free circula- tion of the sap in the plant. In this way the leaf acts both as a feeding and circulating organ.
The Stem.—Most plants, during their period of erowth, assimilate a greater quantity of material than is immediately employed in building up tissues, and this excess of food-material is stored away in some part of the plant adapted for its accumula- tion. The form in which the reserve is accumulated varies ; thus there is the starch in the root of cas- sava and arrowroot, oil in the seeds of various plants, and in the sugar-cane sugar is stored up in the stem. These reserves are generally drawn upon to meet the demands of rapid growth at the times of flowering and fruiting, and doubtless it is with this object that the sugar-cane still accumulates sugar, though by cultivation the production of seed has been dis- couraged, while the tendency to secrete sugar has probably been fostered and increased.
Thus we have: 1. The root, supplying mineral and nitrogenous food and water. 2. The leaf, sup- plying carbonaceous food under the influence of sunlight, and throwing off the surplus water. 3. The stem, acting as a storehouse of reserve food- material, sugar.
The reader is advised to consult a botanical text- book for a more complete account of the structures and functions briefly given in outline here.
CHAPTER II.
Origin of Soil, Clay, Chalk or Marl, Sand.—Fertile Soil.—Condi- tions Influencing Fertility.—‘‘ Condition or Heart.” —Func- tion of Vegetable Matter in the Soil.—Moisture.—Mineral Plant-food.—Analysis of Soils.—Nitrogenous Plant food.— Nitrification.—Leguminous Crops and Nitrogen.—Root-nod- ules.—Retention of Plant-foods by Soils.—Drainage.
N practical agriculture the first thing to be con-
sidered is the soil, for on the nature of the soil
will depend the kind of crops which can be grown,
and whether the undertaking will prove remunera- tive.
Soils have their origin in the decomposition of rocks, and will differ in composition and character according to the nature of the rocks from which they are derived. A cursory glance in almost any country will show soils in process of formation ; the rocks exposed and supporting a scanty vegetation, the roots of which, penetrating the small fissures, tend to enlarge them, while the whole plant causes soil to accumulate by preventing the rain and wind from removing the finer particles, to which the action of the weather, amongst other things, gives rise. On the death of the plant its decaying remains increase the amount of soil and render the spot capable of supporting a much more vigorous growth of plants ; and this combined action of weather and vegetation goes on till often a very considerable
16 MANUAL FOR SUGAR GROWERS.
depth of soil is formed. The action of the weather alone might give rise to a clay, the presence of vege- table matter being necessary to render this a true soil. Rocks are divided into two classes, according to whether they owe their origin to volcanic agency or have been deposited in water; and these facts have an important bearing on the nature of the soil and on the agricultural operations to which it should be subjected. Apart from their geologic origin, soils may be divided into clays, marls, and sands, and this division is of immense service in agriculture. Clay has its origin in the decomposition of rocks containing felspar, and when pure consists of sili- cate of alumina; it very rarely occurs in a pure state, being usually mixed with varying amounts of sand, marl, etc. Itis characterized by its coherence, plasticity, want of porosity, and slow permeability by water; many of these properties are disadvan- tageous from an agricultural point of view, and re- quire to be modified by judicious operations of tillage, ete. Pure clay also contains no plant-food, but the clays usually existing as soils contain considerable admixture of substances of value. Clays may have their origin in both volcanic and sedimentary rocks. Chalk,—or, as it is frequently termed, marl, — when pure, is carbonate of lime, but, as existing as soil, it owes its origin to the decomposition of coral, shells, and the like, and thus contains a variety of substances valuable as plant-food, particularly phos- phate oflime. Mazrls, not containing much sand or stony matter, tend to set into a stiff, clay-like soil, which may be termed coral clay or marly clay; and
MANUAL FOR SUGAR GROWERS. L¢
this, though often rich in plant-food, requires skilled management to keep it in good condition and ena- ble it to produce large crops.
Sand is the term applied to those soils possessing but little coherence and very permeable by water ; the mineral of which it is composed is frequently silica or various silicious minerals. When the fragments or individual particles are large, the term gravel is employed. Pure sand, like pure clay and pure chalk, is incapable of supporting vegetable life, so that nei- ther of these substances in a pure state will consti- tute what is generally understood by the term soil.
A fertile soil consists of an admixture in varying proportions of the three substances above named, together with a suitable amount of vegetable matter in a state of partial decay, and known as humus, aiding the supply of nitrogen, and also such min- eral matters as will supply the requisite potash, phosphoric acid, lime, magnesia, iron, sulphuric acid, and those mineral substances already referred to; for a soil to be fertile these must be in appro- priate quantity, and in such condition that the grow- ing plant constituting the crop can readily absorb them, and the varying fertility of soils depends, amongst other things, on the amount of available plant-food present. These mineral matters are usually present in the rocks from which the soils are derived: thus volcanic rocks contain, felspar, whethorwhele or decomposed into clay; and the soil thus formed is generally rich in potash. Marls, or chalky soils, frequently contain much phosphoric
acid, owing to the presence of that substance in the 2
18 MANUAL FOR SUGAR GROWERS.
living animals whose remains give rise to this kind of soil.
The knowledge of the conditions influencing fer- tility constitutes a large portion of the science of agriculture; among the chief of these conditions are: 1. Weather, with its supply of rain, sunlight, and warmth. 2. Plant-food required by the partic- ular crop under consideration,—in this case, the su- gar-cane. 3. The condition of the land as regards what agriculturists usually know as heart.
In order to constitute what is known as good condition or heart, several things are necessary. It is essential that the soil be sufficiently loose and friable, that the roots may penetrate it with ease ; the soil must also possess the power of retaining sufficient moisture to sustain the life of the plant, and at the same time must not retain too much, or it will become waterlogged, when most plants will re- fuse to grow init. It is essential, too, that the soil contain air, for plants will only grow in the pres- ence of air and will refuse to penetrate a soil whose pores are devoid of it, as in the case of wet or under- drained soils, where the growth is always checked. The influence of air upon root-growth is often well shown when roots obtain access to drains, the growth often being so abundant as to choke the drains.
These three conditions are favourably developed by the operations of ploughing, digging, or forking, the soil being loosened, the particles separated from each other, the capacity for retaining air and moist- ure much increased, at the same time that the re- moval of excessive moisture is facilitated.
MANUAL FOR SUGAR GROWERS. 19
The presence of humus or decayed vegetable mat- ter is essential ; this humus plays many important parts : in stiff clay soils it keeps the minute parti- cles of the soil apart from each other, thus causing the soil to remain both friable and porous ; in sandy soils it holds the particles together, thus giving the requisite coherence. Its presence assists the reten- tion both of water and air, factors which have been shown to be essential to fertility. The correct ap- preciation of the part played by vegetable matter in the soil is of vast importance to the sugar grower.
The porosity of a soil which, as has been seen, de- pends largely on two things, tillage and humus, has a great influence on the retention of moisture dur- ing a dry season and its escape during a wet one. A compact, non-porous soil becomes much hotter under the influence of the sun’s rays than does a porous one; consequently during a drought moisture is much more rapidly lost from a compact than from a porous soil. Further, in a compact soil moisture is drawn up from a considerable depth by capillary attraction ;* in a porous soil, the air-spaces being larger, capillary attraction is lessened: hence a porous soil remains moist for a considerable time, while a compact one becomes dry and cracked. The importance of this fact can hardly be too strongly insisted on, particularly in tropical agriculture. A simple experiment clearly demonstrates the truth of what has been said. Into two tins of similar size and shape equal quantities of dry soil are placed,
* Capillary attraction is the force which causes fluids to ascend tubes or cavities of very small bore.
20 MANUAL FOR SUGAR GROWERS.
and an equal quantity of water added to each; the two tins and their contents are now precisely alike in weight and other conditions ; one is left thus, but the contents of the other are closely pressed together, so as to imitate the condition of a badly tilled soil. The two tins are now exposed to the sun for several hours, care being taken that the conditions of ex- posure are equal; after a time they are carefully weighed to ascertain the quantity of water lost by evaporation. It will be found that the porous soil loses moisture much less rapidly than the other. The following results were obtained by the author in an experiment conducted as described :
Two TINS, EACH CONTAINING 694 GRAMMES OF AIR-DRIED Sort AND 100 GRAMMES WATER.
Compact soil. Loose soil. Loss Ist day ......s.% 5 Roce 24 grammes | 19 grammes Boss 20 days 223.026 aS Senor 15 es 10 s EOg8, 0007.5 5. + samen seer ties < 8 te 7 ag qUOSS 10, SAYA... 23's eae ee eee oe 47 36 a
The loose soil at the end of three days has twelve and a half per cent. more moisture than the com- pact one.
It must also be remembered that in tropical and sub-tropical climates, during a period of drought, heavy dews are not uncommon ; if the soil is porous a certain amount of moisture in the form of dew will be deposited in the soil itself, thus assisting plant- life at a critical time.
That a porous soil parts with its surplus water
MANUAL FOR SUGAR GROWERS. 21
more freely than a compact one, is self-evident and calls for no further comment here.
Porosity of soils, then, must be maintained by til- lage and the introduction of vegetable matter as a means both of retaining the requisite quantity of moisture and of enabling the excess to drain away.
Plant-food in soils.—All plants appear to require essentially the same kinds of plant-food, but in va- rying proportions; the adjustment of the kind and quantity by artificial means constitutes the art and Science of manuring.
Plant-food derived from soil may be classed as mineral and nitrogenous. The mineral matters found in plants are potash, lime, magnesia, oxide of iron, silica, phosphoric acid, sulphuric acid, chlorine (as chlorides), with others of apparently less importance, such as soda, alumina, manganese, ete.
Now, from what has been already said it is evident that, to be of value, these must exist in the soil in a form capable of being absorbed by the plant-roots ; that is, they must be capable of being dissolved. It might therefore be assumed that the quantity of mineral matter available as plant-food in a soil might be easily estimated by finding how much was capable of being extracted by water. If the experiment be made, it will be found that little or no potash or phosphate, for instance, can be removed by treatment with water, even from soils bearing luxuriant crops ; it follows, therefore, that the root must possess some solvent power not possessed by water, by which means it is enabled to dissolve and assimilate that portion of the plant-food insoluble in water. From
22 MANUAL FOR SUGAR GROWERS.
the root some acid exudation takes place, and this attacks the plant-food, dissolving it and fitting it for entrance into the root by the process of diffusion. This power is well shown by an experiment devised by Professor Sachs (“‘ Text-book of Botany,” first English edition, p. 625). Tf polished plates of mar- ble or phosphate of lime are covered with sand to a depth of a few inches, and seeds are then sown in the sand, the roots which strike downwards soon meet the polished surface of the mineral and grow upon and in close contact with it. After a few days an impression of the root-system is found corroded in rough lines on the smooth surface; every root has at the points of contact dissolved a small portion of the mineral by means of the acid water which per- meates its outer cell-walls.
The author, therefore, in the process of soil-analy- sis makes use of very dilute cold hydrochloric acid to extract the available mineral plant-food, believing that by this means he obtains a fair approximation to the process of nature.
The quantity of plant-food removed by a crop varies, as has been said; Warington gives the fol- lowing quantities in pounds per acre.
————— —
nam ae
R =| = Ss 5 o
2 Ad iD i > ‘a a | =| i=} fm o a meslelal| 2 ia¢ls|h/asl5| 4 Sons | 6 1S) 8 is leat |S E | a| eG jalal|ae |oja Wheat-erain .............. 1,800| 33 | 2.7; 9.3 | 0.61.0 3.614.2 0.1| 0.6 Wheat, total crop ......... | 4,958 | 48 | 7.8 28.8 | 2.6 9.2 7.121.1) 2.5/96.9 Barley, total crop ...... .. 4,527 | 48 | 6.1) 35.7 | 5.0; 9.2, 6.9.20.7| 4.1|68.6 Osis: total crop. 5... | | 4,725 | 55 | 8.0) 46.1.| 5.411.6 8.7|19.4) 6.6|85.3 Meadow hay, total crop ...| 3.360 49 | 5.7 50.9 | 9.2 32.114.412.3 14.6/56.9 Turnips, total crop.... ... 49,504 112 |20.9 148.8 24.5,74.0) 9.5)33.1/22.1) 7.7 Potatoes, total crop ....... \17,714| 67 | 5.2, 79.7 | 4.2,26.8,19.1/24.3) 5.9) 4.7
MANUAL FOR SUGAR GROWERS. 23
The weight of an acre of soil to a depth of nine inches is about 3,000,000, or 3,500,000, pounds ; it will thus be seen that even a small proportion of plant-food will amount to a very large weight when calculated to pounds per acre; and this is important in considering chemical analyses, where the propor- tion of various constituents is often stated in parts per one hundred ; thus one per cent. would represent 30,000 or 35,000 pounds, or about sixteen tons per acre to a depth of nine inches. The quantity of solu- ble matter shown by chemical analysis may often seem to be extremely small, and very accurate methods must be followed if trustworthy results are to be obtained. The following table gives some idea of the amounts of plant-food soluble in dilute acid, in the manner already alluded to, in the case of cer- tain soils under cultivation in sugar-cane.
MINERAL PLANT-FOOD PER MILLION POUNDS OF SOIL, OR PER ACRE THREE INCHES DEEP, SOLUBLE IN DILUTE ACID.
Mineral substance. We MS [enn Vial Wie Wales | WAGE || \A00G) IDG |) ore STILTCE (SH OF) een eae 970 |1050)1010 6995 1323/1874! 1776 | 1121 1028; ? ime (CaO) . 225602 3. 1932 |2597|2538 4266 4420/4083 3810 | 5415 100000 400000 Magnesia (MgO) ..... 300 | 400) 320 1203 500\19384 760 980 |100000 400000 Oxide of Iron (Fe,03) 750| 850 800) 45, 210) 144; 120 ? 3650) 3500 otrashi(KO) ..)..052 52% 37| 94) 38) 256, 80] 61) 33 27 169 267 Phosphoric acid | |
(P,0;)| 47] 28) 28) 65) 86] 37 70 18 185 8T Sulphuric acid (SO) . trace | |
I., I1., and III., volcanic soils, Montserrat, W.I. IV., V., and VI., volcanic soils, Antigua, W.I. VII. and VIII., sedimentary, non-calcareous soils, An- tigua, W.I. IX. and X., calcareous soils, Antigua, W. I.
Now, the undecomposed portion of the soil usu- ally contains a very appreciable amount of plant-
24 MANUAL FOR SUGAR GROWERS.
food not readily dissolved by plant-roots, but which by the action of the atmosphere is slowly brought into such a condition as to be capable of being dis- solved ; we can thus divide the plant-food into that which is available and that which is slowly avail- able. In a chemical analysis it is usual to regard those constituents which are insoluble in cold dilute acid, but which are soluble in warm strong hydro- chloric acid, as slowly available. This slowly avail- able plant-food is by no means to be overlooked in forming an estimate of the value of a soil, as it con- stitutes a kind of capital and indicates that soils possessing an abundant store will yield abundant crops with the minimum of manure, or of that special constituent which happens to be present. Below is given a comparison of the amount of cer- tain substances soluble in dilute and strong acids, respectively, in certain soils.
1B | 10 F
2)
trong. | Dilute. gee Dilute,
LR eee ee Oper cae 6460 | 541
5 | 7770 | 6227 | 12820] 5248 Magnesia: i... -%.. - 5514 | 283 | 8280 | 13880 | 13193 57 (ch ne 159 20 Ate 20 | 1340 | -8e74 Phosphoric acid..... | 146 | 45 209 129
Where no crops are removed from the soil, as in the case of forests and prairies, the fertility of the soil will actually increase from year to year, owing _ to the gradual conversion of the slowly available into the available mineral plant-food; at the same
MANUAL FOR SUGAR GROWERS. 25
time the decaying vegetable matter increases the humus and returns to the soil those mineral mat- ters which entered into its own structure, thus increasing the soil’s fertility. These soils are gen- erally spoken of as virgin soils, and will often bear luxuriant crops for years without manures; but sooner or later they become more or less ex- hausted, and the art of the farmer is required, that by proper manuring they may be kept in a condition to produce remunerative crops.
The constituents of mineral plant-food which are usually first exhausted are phosphoric acid and pot- ash. Hence the importance attached to the pres- ence of these substances in manures. To these in certain cases may be added lime and iron.
Thus far attention has been directed to the min- eral plant-food, there yet remains a great deal to be said on the subject of manures supplying nitrogen.
Nitrogen is an essential constituent of the food of both plants and animals, just as carbon and the various mineral constituents are. It has been seen how the mineral matters are obtained from the soil, and how the carbon is obtained from the atmosphere ; now, four-fifths of the atmosphere consists of nitro- gen, which would thus appear to provide an abun- dant supply of this important plant-food; yet it is found that plants cannot derive their nitrogenous food from the air, but that it all comes from the soil. (As to the nitrogen in the case of leguminous plants, see page 28.) All organic matter contains more or less nitrogen, and thus organic matters,. such as animal excreta, pen manures, green dress-
26 MANUAL FOR SUGAR GROWERS.
ings, dried blood, etc., are nitrogenous manures, several of these being humus-supplying manures as well. The need for humus and its action on the soil has been already dwelt upon.
The various nitrogenous compounds in the or- ganic substances, and in the ammonia salts above mentioned, are not in a fit condition to serve as plant-food without undergoing change; careful ex- periments have demonstrated that plants usually absorb their nitrogen in the form of a salt of nitric acid, or a nitrate, as it is termed.* Now, when organic matters or ammonia salts are mixed with soil, chemical changes take place, and the greater part of the nitrogen is converted into nitrate by a process very similar to fermentation. The re- searches of recent years—prominent among them being those of Warington, Schlosing, and Muntz— have proved that this conversion into nitrate is the work of a minute microbe or germ which is present in all fertile soil. This microbe is found in greatest number and in greatest vigour near the surface of the soil, and penetrates to various depths according to the character of the soil. For its active growth, and in order that it may carry on its useful function of converting organic matter into plant-food, sev- eral conditions are necessary: 1. A substance con- taining nitrogen and capable of being acted on by the microbe; such things as organic matter or
* Nitric acid is a compound of hydrogen, nitrogen, and oxygen, having the formula HNO;; the hydrogen may be replaced by metals, as in the case of potassium nitrate or saltpetre, KNOs, or sodium nitrate, NaNQs.
MANUAL FOR SUGAR GROWERS. 27
ammonia salts fulfil this condition. 2. Air; and this is one of the reasons why tillage and working the soil increases the fertility, as it leads to more rapid nitrification. 3. Moisture. 4. A tempera- ture of from 40° F. to 110° F., nitrification being most active at a temperature of about ordinary summer heat. From this it will be seen that the natural condition of affairs in the tropics — high temperature with abundant moisture—is conducive to rapid nitrification. 5. It is necessary that some base be present in the soil, 7.e., some substance capa- ble of neutralising acids; in almost every case this condition is fulfilled by the presence of carbonate of lime or chalk, and this is one of the reasons why this substance is so important as a constituent of soils. It is very evident, then, that many of the points which were regarded as of importance in connection with condition or heart are those which are favourable to nitrification ; and thus the theory of nitrification supplies us with a reason for per- forming many agricultural operations which previ- ously rested only on a basis of tradition of success- ful practice.
The author has seen certain West Indian soils exceptionally rich in nitrogen, yet containing barely a trace of nitrate, owing to the non-fulfilment of some of the conditions given above, and this chiefly due to defective tillage and to the trampling of cat- tle on wet lands. In one instance a sample of soil which, when taken from the field, contained nitrate equal to only six pounds per million, after being kept in the laboratory for twenty-eight days, contained
28 MANUAL FOR SUGAR GROWERS.
nitrate equal to one hundred and thirty-three pounds of nitrate of soda per million, thus proving that con- dition and not manure was what this particular field lacked.
From what has been said, it follows that nitrate of soda is practically the only nitrogenous manure — absorbed by the plant without having to undergo change under the influence of the nitrifying mi- crobe.
Recent researches have led to the conclusion that plants belonging to the natural order Leguminose, which includes all plants of the pea and bean tribe, take up their nitrogenous food in a different manner from other plants ; they can apparently freely assim- ilate nitrogen compounds other than nitrates, and it has been found that the weight of nitrogen in a leguminous crop may exceed the weight of nitrogen in the soil and manure used before the crop was srown. The inference is, then, that leguminous plants, unlike others, can make use of the nitrogen of the atmosphere. It is also found’ that leguminous plants have curious little swellings or nodules upon their roots, varying in size and shape on different plants; on the pigeon-pea (Cajanus indicus) these swellings assume large dimensions, sometimes being an inch or more in diameter. The internal struc- ture of these nodules, as far as they have been ex- amined by the author, appears to be as follows: There is an external layer resembling the bark of the root; immediately within this comes a cellular layer traversed by fibro-vascular bundles; in the centre of the nodule is a mass of cellular tissue (a, Fig. 6),
MANUAL FOR SUGAR GROWERS. 29
many of the cells of which contain starch ; distrib- uted throughout the central mass of tissue are a number of what the author distinguishes as “ special cells” (b); these are usually rather large in size and do not contain starch, but are filled with countless bacteria or microbes. Not very much is known re- specting these root-nodules, the active agents in which appear to be the bacteria or microbes ; for the nodules do not form on the roots of plants grown in sterilised soil, that is, in soil subjected to such treatment, before the seeds are planted, as will de- stroy vegetable life, and that they will form if a little unsterilised soil be af- terwards added to the sterilised. It has been as- sumed (for very little has been proved so far) that these bacteria, which appear to exist in all fer- tile soils, have the power of forming colonies on the roots of certain plants, and that so situated they have the power of assimilating atmospheric nitrogen ; and that after its assimilation by the bac- teria the nitrogen becomes available for the food- supply of the host on which the nodules are found. It has even been suggested that these bacteria are capable of assimilating atmospheric nitrogen without being associated with another plant. The increase of nitrogen in a leguminous crop renders these plants very valuable for the purpose of green dress- ing, as this will result in a gain of nitrogen to the
iN J dis ue PSY /
Fia. 6.—Section of root-nodule
(magnified).
30 MANUAL FOR SUGAR GROWERS.
soil as well as a gain of vegetable matter or humus ; whereas green dressings of other classes of plants merely restore the nitrogen taken from the soil.
It is found that some of the plant-food constitu- ents of the soil are soluble in water, as for instance, nitrates and chlorides, and therefore these substances are found in the drainage-water ; on the other hand, some of the constituents are insoluble, as potash, phosphates, and ammonia; these things are seldom found in drainage-water (see page 21). Pure sand possesses little or no retaining power for the various food constituents; and thus, if soluble phosphates, or potash salts, or ammoniacal chemical manures are mixed with sand, it is found by experiment that they are readily washed out by water. If, however, these substances be mixed with a good soil containing clay and humus, it will be found that they are not washed or removed by water. Potash, ammonia, and phosphoric acid are retained by soil by virtue of chemical action ; precisely how this takes place is not clear, but the hydrated oxides of iron and alumina, the hydrated forms of silica and humus, doubtless play an important part in the process. (See Warington, “ Chemistry of the Farm,” p. 28.) The retention of the phosphoric acid is largely due to the oxides of iron and alumina and to lime; the potash is probably chiefly retained by humus and the hydrated silicates of alumina; the ammonia is chiefly retained by humus. In the case of potash and ammonia salts, it appears necessary that they should present themselves in the form of carbonates ; if the sulphates, etc., of the substances be used,
MANUAL FOR SUGAR GROWERS. dl
they undergo decomposition with the carbonate of lime in the soil, forming carbonate of potash or am- monia and sulphate of lime, and the potash and am- monia in this form is retained by the soil. From this it will be seen how necessary it is to have a suf- ficient quantity of lime in the soil, and why marling tends to improve certain soils.
Now, for certain substances the soil possesses but little retaining power, such as nitrates and chlorides, and these substances are always found in drainage- waters ; it will at once be seen that this fact has an important bearing on the application of nitrogenous manures. It will be remembered that all compounds of nitrogen are converted into nitrate by the action of the nitrifying organism of the soil, and now it is seen that soils have but little retaining power for nitrates ; hence it follows that if heavy dressings of nitrogenous manures, particularly nitrates, are placed on the soil, there is a risk of loss by washing out in the form of nitrates, unless the substance nitrifies slowly and at about the same rate as the plant ab- sorbs its nitrate. Nitrate of soda or sulphate of am- monia should therefore be appled in small quanti- ties, at tolerably frequent intervals, while organic matter containing nitrogen, which nitrifies more slowly, may be applied in larger quantities and at greater intervals. In the tropics, the high tempera- ture increases the rate of nitrification, and this, with the usually heavy rainfall, renders the risk of loss of nitrogen greater than in cold climates; hence the proper comprehension of the relationship of.soils to nitrogen, and particularly to nitrified nitrogen, is a
2 MANUAL FOR SUGAR GROWERS.
subject worthy of attention and study on the part of all practical sugar growers.
Even if plant-food is present in sufficient quantity for the requirements of a crop, there are various cir- cumstances, as we have seen, greatly influencing fertility ; it is well known, for instance, that varia- ations of the weather will cause greater differences in crops than can be obtained by manuring.
A soil must be capable of retaining plant-food and moisture, and thus, as shown above, must contain a due proportion of clay and humus. A clay soil, on the other hand, may become so close as to be un- fertile, owing to the absence of sufficient air, so essential for root-growth and for nitrification, and also be so dense as to offer great resistance to the entrance of the fine, delicate root-tips and root-hairs. This question has been already discussed when treating of condition or heart (page 18).
It is important to remember that the points by which good condition is determined are such as do not admit of expression by figures in a statement of a chemical analysis; so that two soils may show a very similar chemical composition, yet differ materi- ally in fertility, owing to difference in condition. In this the practical field observations of the planter are of great value, and chemical analysis can only supplement, and not supplant, this. The application of purely chemical manures to land in bad heart is a mistake frequently made, and tends to discredit the value of chemical aid in manuring. ‘The planter should carefully avoid this error, the remedy for which lies in the correct exercise of his own judg-
MANUAL FOR SUGAR GROWERS. 33
ment. Chemical manures will only exert a full and beneficial action on soils already in good condition, but which are deficient in some one or more sub- stances constituting plant-food ; and of these, phos- phoric acid, potash, and nitrogen are those usually deficient, and which it is the function of the ordi- nary chemical manure or fertilizer to supply. The necessity for supplying other ingredients, such as lime, magnesia, iron, etc., is sometimes pointed to by special investigations, when the defect must be remedied.
Drainage-—When a heavy shower of rain falls, a certain quantity of water sinks into the ground, and when the soil becomes saturated—if the fall is more rapid than the absorption—a certain quantity flows over the surface and is carried away by the ditches and streams. If the rainfall continue for some time, the soil becomes entirely saturated, the water occupying the space previously occupied by air. Now, it has already been shown that this condition is highly unfavorable to the growth of such a crop as the sugar-cane, which, as with most other crops, requires a soil containing both air and moisture. It is necessary, then, that the excess of moisture be re- moved. Some porous soils are so situated that when the rain ceases they naturally part with their excess of moisture with sufficient rapidity to permit the entrance of the necessary air; such soils are said to possess natural drainage, and merely require attention to be directed to the channels for the es- cape of the surface water; such soils, however,
are not common. Other soils retain water for too 3
34 MANUAL FOR SUGAR GROWERS.
long a period, and are said to be cold or wet ; this may arise from want of porosity, as in the case of stiff clays, or from a flat and low-lying situation, or more frequently from a combination of the condi- tions. The remedy for this lies in draining.
Draining may be accomplished by two principal methods—surface or open-trench draining, and sub- soil draining. So far, in our West Indian colonies, the former method is the only one regularly prac- tised, and the author’s experience is that one of the real objects of the operation is frequently lost sight of or ignored. It is commonly supposed that sur- face drainage, as here accomplished, has for its ob- ject merely the removal of the superfluous surface water, and, that being accomplished, that it is well to leave the land wet. How erroneous this is has al- regdy been shown. It is necessary to remove all superfluous water to a considerable depth, so as to admit air, and thus—particularly on flat lands—it is desirable to dig the trenches to as great a depth as possible. The depth and distance apart of the trenches of course entirely depends on the nature of the land. A loose porous soil resting on a por- ous subsoil will only require such open trenches as will carry off the surface water during heavy rains. A stiff clay resting on an impervious subsoil will require close and deep trenching. The most con- venient distance for trenches is thirty or forty feet apart, and in stiff soil they should be at least eigh- teen inches deep.
Open trenches, however, possess many and great disadvantages ; and in countries where agricultural
MANUAL FOR SUGAR GROWERS. 35
practice has made any substantial advance, some form of subsoil draining is resorted to. If we dig down a sufficient depth into the soil we shall reach a level where the soil is always moist, except in periods of prolonged drought,—a level at which the amount of moisture is but slightly affected by the changes from wetness to dryness, etc., experienced by the soil nearer the surface ; the pores of the soil at this level are practically permanently filled with water, and we may designate this the permanent water-level. The depth at which the permanent water-level will be met with entirely depends on the character and position of the soil; should it be at such a depth that there is ample room above it for the de- velopment in the overlying soil of the full root- system of the crop, then such a soil will not be bene- fited by subsoil drainage ; it is drained naturally. But such soils are rarely met with, the permanent water-level is usually at no great distance from the surface, and it has been repeatedly explained that roots will only grow in soil whose pores are filled with air. The roots never grow down below the per- manent water-level ; if this is near the surface, it fre- quently happens that the depth of soil available for healthy root-development is far too limited to allow the growth of a full and luxuriant crop; consequently, if the season be a favorable one, the root-develop- ment being limited, the crop can only be moderately large ; while, if the season be wet, the small depth of soil becomes waterlogged, and active root-growth is impeded ; on the other hand, if the season be dry, the roots, having only a shallow range, soon lack mois-
36 MANUAL FOR SUGAR GROWERS.
ture and suffer from the effects of the heat of the sun. If, however, the permanent water-level be lowered by subsoil drainage, the roots have room for luxuriant growth, thus ranging over a greater space to absorb moisture and plant-food,—a state of things which soon shows an abundant result in the increased growth of the portion above ground, with its consequent increase of the crop. Again, a deep- rooted plant is much better protected against changes of season than a shallow-rooted one: in a wet season the porous upper soil absorbs a large amount of moisture which the subsoil drain quickly removes, - leaving the soil in good condition for plant-growth ; in a dry season the small amount of moisture from passing showers, dew, etc., is much more effectively retained, and the roots of the crop, having a deeper range, find a greater amount of moisture and are farther removed from the hurtful effects of the heat of the sun. The deep porous soil also retains a use- ful amount of moisture for a longer period than a shallow one. It follows, then, that subsoil drainage is beneficial, both in wet and in dry seasons. Various methods of subsoil draining have been devised, all of which are carried out by opening a trench to the required depth of the drain, and plac- ing in the trench something to leave a channel or waterway along the bottom when the earth is thrown back again into the trench. Many kinds of material have been used for this purpose, such as brushwood, loose stones, stones or brick or tiles roughly built to form a small culvert; and finally coarse unglazed earthenware pipes. This last ma-
MANUAL FOR SUGAR GROWERS. 37
terial has been found to answer most successfully ; the other forms of drain are found, sooner or later, to become filled with earth and are thus rendered useless, whereas the earthenware .drain-pipe prop- erly laid will remain in good order for a long term of years, probably twenty or thirty.
The actual operation of laying tile drains in a piece of land is one which requires careful consid- eration beforehand, and if possible the work should be conducted by workmen having practical knowl- edge and experience of tile-laying. The points to be considered are, the size of pipe required, the depth of the drains, and their distance apart. For most work pipes having an internal diameter of one and a half inch will serve for the drains, and if these are connected with a main drain, as they fre- quently require to be, this main drain must be of sufficient capacity to remove freely all the water collected by the small secondary drains, and its size will be determined by their number. In laying tiles, levels are carefully taken, and trenches are opened, with specially shaped tools, to the required depth ; care is taken that the earth at the bottom of the trench is disturbed as little as possible, all treading or walking in the trench being avoided ; the tiles are laid end to end, and the joint is covered with a short length of pipe Ce of larger size, as shown in the figure ; the earth F-. 7.—Diagram of pipes and joints is returned to the trench ta eae and is firmly pressed down. It is desirable to leave the earth at the surface somewhat raised over the
38 MANUAL FOR SUGAR GROWERS.
trench, to prevent the surface water converting the trench into an open channel, whereby the drain is injured. Proper precautions must be taken to prevent the access of rats and other small animals to the drains. The danger of the drain silting up is avoided by a careful adjustment of levels, so that the water runs with equal velocity throughout the length of the drain, or perhaps, with advantage, with slightly increased velocity near the outlet. Silting up depends to a great extent on the relation of the size of pipe to the water flowing through it ; a small pipe running nearly full not silting so much as a large one carrying only a small quantity of water. For details respecting tile draining the reader is referred to special works on the subject. For sugar-cane the author would suggest that the drains be laid about thirty to forty feet apart and four feet deep. This system of draining is some- what costly, requiring a large outlay at first, and up to the present time it has been but little practised in the West Indies ; in the sugar-growing districts of the United States it is being adopted with suc- cess, an example which should be followed by West Indian sugar growers; it is doubtless the way of preventing losses from short crops during droughts. It is difficult, in the absence of actual trials, to state the cost of such a system of draining in the West Indies, but there is little reason to doubt that it would prove remunerative, as it would increase the crop and at the same time decrease the cost of work- ing the land; for the surface trenches would only require to be deep enough to deal with the surface
MANUAL FOR SUGAR GROWERS. 39
water, and would not be required to act as drains in the true sense of the word; this would reduce the cost of opening and cleaning out trenches, and ereatly facilitate the cartage of the cane crop off the land; the work of ploughing would also be rendered easier, the deep trenches, frequently deepened and widened by the action of the water, offer serious ob- stacles to these operations, entailing considerable outlay, and rendering the work of the cattle and mules hazardous and cruel. With a system of tile draining it will doubtless be possible to cultivate the sugar-cane on land kept flat or nearly so, instead of being “holed” as at present, in which case the use of horse-hoes and weeding-machines will be possible, thus reducing the expenses incidental to the early stages of sugar-growing.
CHAPTER III.
Sugar-cane.—Preparation of Land, Planting, Manuring, Weed- ing.—Cutting Cane.—Methods of Dealing with the Trash.— Moulding.
AVING briefly sketched the general principles
on which a scientific system of agriculture
should be based, it is now necessary to confine at-
tention more particularly to the methods of cultiva- tion employed in the case of the sugar-cane.
For several months the planter has been carefully ploughing and preparmg the land to be planted, and in November or December the actual planting of the cane usually commences and is carried on for seve- ral months, so that there may be a succession of fields, one ripening after the other, in such a manner as to render the proper reaping and manufacture practicable.
On land of a fairly stiff character and lying some- what flat, so as not to be subject to loss of surface mould by the rush of water during the heavy rain- storms of the tropics, it is usual to prepare the land in furrows and banks, an operation known as “ hole- ing ;” the furrows are generally four and a half feet or five feet from centre to centre, a distance of six feet being sometimes adopted; the banks vary in height, ranging from one to one and a half feet above
MANUAL FOR SUGAR GROWERS. 4]
the bottom of the furrows. If farm-yard or pen manure is used,—and either this or green dressing is generally very necessary,—it should be well ploughed in during the preparation of the land for planting, preferably before the holeing or banking process. It is not an uncommon practice to defer the appli- cation of manure of this kind until the preparation of the land is completed, and often until after the cane has been planted. This is a mistake, as the function of pen manure is a double one: first, to sup- ply vegetable matter to form humus, the importance of which has been fully dwelt upon and its action in loosening the soil explained ; and it is as a mechani- cal manure, as a means of improving condition or heart, that pen manure is most useful; its second property, that of a fertilizer, is not to be overlooked, but is secondary to the one already alluded to; and it is to secure the full benefit of the first of these prop- erties that complete covering and mixing with the soil is desirable.
Another method of preparing the land for plant- ing, which has some good features, consists in cross- holeing ; this differs from the plain holeing or bank- ing in having a cross-bar raised at right angles to the furrow, thus forming a number of square holes, and in the bottom of each a cane-plant is placed. The use of cross-holeing appears to be twofold : in the first place it restrains the flow of surface water and prevents loss of mould by washing in heavy rain ; if the land be sufficiently porous the water retained in the holes will soak through the soil and drain away without injury to the plant ; on stiff land or in a wet
42 MANUAL FOR SUGAR GROWERS.
season there is some danger of waterlogging. The second beneficial effect of this operation is due to the extra tillage caused by the raising of the cross- bar, some increase of nitrification resulting from this. Some of these beneficial effects—probably all, and to a greater degree—could be obtained by tile draining with flat cultivation and machine weeding and tillage.
In whatever way the ground has been prepared, the next operation to be performed is the actual planting. For this purpose it is customary in the West Indies to use the upper part of the sugar-cane ; this, as it contains but little sugar and a large pyro- portion of glucose or molasses sugar, is useless for erinding, hence there is no loss of cane for seed or planting purposes. In some countries it has been the custom to employ the whole of the cane for planting, either laymg whole canes in single or double rows in the furrows and covering them with earth, or planting short lengths of one, two, or three joints. As these methods of planting offer no advantages over the use of the top or end of the cane, there appears to be no reason why they should be retained. Some exercise of judgment is required on the part of the planter so to arrange matters that he may have canes to reap to supply himself with plant-tops at the required time, and in December and January it is not usual for the regular crop to be ready for reaping ; it is therefore a common prac- tice to leave a late field of canes as “ stand-overs,” or to allow a ratoon crop to grow for the special pur- pose of providing tops for planting. These ratoons are cut while probably the canes are but short, the
MANUAL FOR SUGAR GROWERS. 43
land is quickly broken up and planted, thus provid- ing plants for itself and for other fields besides.
The plant-top consists of the three or four upper joints of the cane which are yet immature ; the leaves are cut off, leaving a piece of the cane about ten inches long, having two or three healthy buds or eyes. The plant-tops should be carefully picked over in order to reject any suffering from the attacks of borer or from any other disease, and as a precau- tionary measure they should invariably be soaked for a short time (an hour or two) in slaked lime and water, two pounds of lime to a gallon of water being a convenient strength; this treatment destroys a ereat many animal and vegetable parasites, though unfortunately there are some, particularly the eggs of certain insects, which are not destroyed by it. In cases where diseases persistently attack the young plants the following method of treatment suggested by Dr. Bancroft is useful : Carefully clean the joints from all trash; then immerse the plants in a mixture of carbolic acid and water heated to such a tempera- ture as the hand can bear, using one pound of acid to fifty gallons of water ; allow the plants to remain in this mixture for twenty-four hours; then immerse in a mixture of lime and water of the strength given above for a few minutes. Careful selection of plant- tops, followed by soaking in lime-water, greatly as- sists In securing an even, well-established growth of young canes.
In selecting tops for planting there are several points to remember. The upper portion of the top should be cut off sufficiently low down to cut out the
+4 MANUAL FOR SUGAR GROWERS.
terminal bud, or when the top is planted the terminal bud will grow in preference to the lateral buds or eyes, giving rise to the appearance known as ‘ capon tail,” from the fact that the first leaves springing from the terminal bud have been partly cut off; the young leaves having thus lost their tips present a truncated appearance suggestive of a capon’s tail. Plants grown in this manner do not bunch well, and the early developed cane arising from the terminal bud ripens before the other canes, and thus tends to arrow. ‘Tops for planting should be taken from sound, ripe canes, those taken from sound but soft green canes rarely grow well. Mr. J. Sutherland was kind enough to make the following experiment at the author’s suggestion: Three tops were planted in three tubs, care being taken to make the condi- tions equal in all three; two of the tops were from mature cane, and one was from young green cane. The two tops from mature cane sprouted in eleven days, while the immature one did not throw out a shoot until the twenty-second day.
Mr. E. R. Hall made the following experiment on the author’s behalf: Three adjacent plots were planted, one with tops from ratoon canes, the indi- vidual tops being carefully picked in order to obtain those of a large size; the second plot was planted with selected small ratoon tops, and the third with sood average tops from plant-canes ; all these canes are now growing, and, so far as the eye can judge, there is no difference between them. |
From these experimeuts, as well as from general experience, it follows that any good, sound, mature
MANUAL FOR SUGAR GROWERS. 45
cane will provide a top suitable for planting. On the other hand, it does not seem probable that the selection of tops is likely to lead to any improve- ment in the variety of sugar-cane ; what is gained is a better growth and more certain establishment of the crop. This view is, perhaps, contrary to the ideas of some planters, but is proved by the follow- ing considerations: Under existing circumstances the tops used for planting are, on the whole, not from the best canes grown on the estates, being fre- quently taken from ratoons not considered worth keeping ; hence it may be held, taking one field with another, that the tops used for planting are from canes in quality something below the best, and if the matter be looked at carefully, they will be found to be from canes below the average quality grown. Now, if selection of good qualities can produce im- provement, selection of inferior kinds—and this is what the present method amounts to—should pro- duce deterioration ; yet it is not suggested that there is any falling off in the quality of the sugar-cane. The above is no argument for careless work, which will produce deterioration only too surely. The top planted reproduces the parent variety with all its characteristics ; new varieties must be sought in canes from seed, or from occasional sports or bud varieties.
The plant-tops are planted in the following man- ner: The ground is marked out by means of a line and marks placed to indicate the spot where each plant is to go, the distances apart varying from four and a half to six feet according to custom (about
46 MANUAL FOR SUGAR GROWERS.
41x 5 feet or 5x5 feet being convenient and profit- able distances). Some discussion has taken place recently as to the advisability of so planting that the plants, instead of occupying the corners of a square, shall stand at the angles of an equilateral triangle :
* * * * * * * % * * * * * * *
The diagrams will make this statement clear. By the latter method it is evident that for a given mini- mum distance between the plants the maximum number of plants per acre can be grown. ‘To carry this into practice, the planting will require to be ar- ranged as follows: if the distance between the plants, measured from-right to left in the above diagram, be taken as 1, then the distance between the rows measured from top to bottom in the diagram must be 0.866; or if a uniform distance of five feet is re- quired between each plant, then the plants must be five feet apart in the rows, and the rows four feet four inches apart, with the plants arranged in an al- ternate manner with those in the preceding row. When planting trees and the like, where the dis- tances apart are considerable, this method is worth carrying out, but for cane cultivation it does not ap- pear to the author to possess much merit. Regu- larity in planting greatly assists many of the sub- sequent operations of cane culture, such as weeding, manuring, etc., and is a great aid in detecting miss- ing or weakly growing plants and admitting of healthy ones being substituted. The ground being marked out, a laborer, armed with an iron bar or
MANUAL FOR SUGAR GROWERS. 47
drill, makes a hole by thrusting the bar into the eround, then places a plant-top in the hole in such a manner that the head of the piece planted is just below the level of the ground, and then covers the whole by an adroit movement of the foot. In about seven to fourteen days the eyes or buds burst into leaf, and growth above ground fairly sets in; but be- fore this the rootlets have commenced to grow from the double row of dot-like markings to be seen above each joint, thus the young plant obtains a supply of moisture and plant-food quite as soon as active transpiration and growth take place.
Various experimenters have recorded observa- tions on the results of planting various parts of the cane, and also of selecting large or in other respects fine tops for planting. The results obtained do not appear to be definite; so far as the author’s experi- ence goes it would seem that any sound, healthy “top,” which has not arrowed or flowered, is suita- ble for planting, and that it will reproduce the vari- ety of cane from which it arose, with all its pecu- harities, including the saccharine richness, ete.
When the young plants have just begun to spring is the most favourable time to apply manures con- taining potash and phosphates. It seems best, to the author, to apply at this time a mixture of sulphate of potash and superphosphate of lime, with lime, marl, or ashes, if the soil is at all deficient in lime. The quantities to be employed will vary with the soil, but generally two hundredweight of super- phosphate and one-half to one hundredweight of sulphate of potash per acre will be found useful
48 MANUAL FOR SUGAR GROWERS.
amounts in the absence of any special information. This mixture should be evenly distributed in proper quantity on the surface of the soil, around and at a short distance from each plant; this is best done im- mediately before weeding, the operation of weeding tending to distribute the manure and to mix it with the soil. It will be observed that no nitrogen is recommended at this stage. If the land is in good condition, and has been treated in the manner de- scribed at the beginning of this chapter, there will be a sufficient quantity of nitrogen, and much of that nitrogen in the readily available form of ni- trate, already in the soil. In about May or June, or earlier, if the growth of the plant shows lack of vig- our, a light top-dressing of sulphate of ammonia in quantity of about one hundredweight per acre should be applied in the same manner as the super- phosphate and potash, and a second dressing of the same quantity should be given six or eight weeks after the first ; a third dressing is seldom necessary or remunerative.
It has been stated that ammoniacal manures should not be applied to soils containing more than 10 per cent. of carbonate of lime, as there is as- sumed to be a loss of ammonia owing to the con- version of the sulphate or other salt into the vola- tile carbonate of ammonia. The author recently made a series of experiments on two soils, one containing 1.3 per cent. and the other 40 per cent. of carbonate of lime. The soil was placed in a shallow glass dish, to a depth of about an inch and a half, a known quantity of sulphate of ammo-
MANUAL FOR SUGAR GROWERS. 49
nia was added in solution, and a definite quantity of water added. A very shallow dish, the bottom of which was moistened with sulphuric acid, was placed above the soil. Any ammonia escaping from the soil would be speedily absorbed by the acid.
Proceeding in this manner, and using one part of sulphate of ammonia to five hundred of soil, the non- calcareous soil gave off in two days ammonia equal in quantity to .017 per cent. of the sulphate of ammonia employed. The results in the case of the calcare- ous soil are given in tabular form below.
500 grms. |500 grms. soil and .5| soil and .2 grms. s.|/ Srms. 8. ammonia. | ammonia.
Per cent. of added ammonia lostin first2 days) 1.10 0.90 " = ue of. ext 3-6 1.02 0.60
42 ee 5 os ae ae 0.72 0.41
Per cent. of added ammonia lost in Sdays| 2.84 1.91
Now, as in all probability the loss is greater un- der the conditions of the experiment than it would be in the field, it does not seem necessary to aban- don the use of sulphate of ammonia on calcareous soils, provided that they are in fairly good condi- tion; in the case of poor calcareous soils contain- ing but little vegetable matter, the loss would no doubt be much greater than in the above experi- ments.
The amount of various substances removed from the soil by a cane crop has been most carefully esti-
mated by Professor Harrison. (See report of Dodds’ 4
50 MANUAL FOR SUGAR GROWERS.
Experimental Station, Barbados, 1889, etc.) He found the amount of phosphoric anhydride to range from 23.5 pounds with a crop of 22.3 tons of cane, to 45.3 pounds with a crop of 32.5 tons, per acre. The potash varied from 55.5 pounds with a crop of 28.5 tons of cane per acre, to 116 pounds with a crop of 38.8 tons per acre. These figures deal with the potash and phosphoric acid in the canes only, irrespective of the amount in the tops. The tops will contain about nineteen or twenty pounds of phosphoric anhydride, and seventy to seventy-five pounds of potash, but on a well-conducted estate these will ultimately find their way back to the soil after having been used for food for the working stock. <A certain amount of the potash and phos- phate, too, will be returned to the soil in the ashes from the furnaces and in the scums removed from the juice, so that, making allowance for these, the quantity of plant-food removed from an acre of land by an average crop of say twenty-five tons of cane per acre will be about fifty pounds potash, twenty- five pounds phosphoric anhydride, and seventy pounds of nitrogen per acre; these amounts of plant-food will be contributed to the soil by the methods of manuring here recommended, and this, with good and careful tillage, should, under reason- ably favourable circumstances, produce satisfactory crops.
Weeding is an operation which will occupy much of the planter’s time and care. This operation has a beneficial action for several reasons: not only are weeds killed and the ground left unencumbered for
MANUAL FOR SUGAR GROWERS. Sill
the full growth of the cane, but the constant stirring of the surface-soil keeps it loose and friable, and the stirring of the soil distributes the manures, thus ensuring an even distribution. Weeding is gen- erally done with the hoe. It would seem, however, as if a time were not far distant when this operation will be done by machines; this will result in more effectual stirring of the surface-soil, with its bene- ficial action, and will make the operation less costly. After the canes reach a certain height the operation of weeding becomes unnecessary, as the dense foli- age of the cane effectually prevents the growth of weeds.
In some places it is the custom to remove the dead leaves or trash from the canes when they are nearly mature, in order to allow air and moisture to circulate more freely and thus hasten the ripening. In damp situations this operation is doubtless bene- ficial ; how far it can be advantageously followed in dry places does not seem to be clear. The author is not aware of any systematic experiments undertaken to throw light on this subject; such experiments could be easily made and would be of interest.
When the canes are ripe, a fact which is ascer- tained by the cessation of growth, and in most vari- eties of canes by a tendency to deepen in colour, the reaping will begin. The canes are cut close to the ground, and the tops are cut off, the immature joints, containing but little sugar, are thus removed and are used for planting, the canes are tied in bun- dles and carried to the factory to be crushed.
If the roots from which the canes have been cut
52 MANUAL FOR SUGAR GROWERS.
are allowed to remain in the ground, a new growth of canes arises, and these are known as first ratoons, or second ratoons, etc., according to the number of erowths thus raised without replanting. Except in soils of extreme fertility the yield of canes steadily diminishes by ratooning, so that on ordinary soils it is not profitable, as a rule, to grow more than sec- ond ratoons. In some districts the growing of ra- toons is regarded with disfavour, and fresh planting is resorted to for every crop. The method of ra- tooning possesses some advantages, and, if the land is well tilled and cared for, would appear to be eco- nomical. One point requiring attention in ratoon- ing is the effectual opening up of the soil to ensure the loose pulverulent condition essential to fertility. It is a good plan, as soon as the canes have been re- moved, to arrange the trash or leaf residues of the old crop on alternate banks, leaving alternate banks clear, then with a double-mould-board plough a good deep furrow is made in each bank free from trash ; half of the trash is now placed in this furrow and the soil is drawn over it by means of the hoe; the remaining trash is buried under the other bank by a repetition of the process. The trash should be covered with soil as completely as possible, in order to promote decay; this decay taking place under the soil will keep it light and porous, thus rendering the operation of breaking up the soil of much more lasting effect than if no vegetable matter had been buried. All those parts of the field which have been much trampled in the removal of the previous crop should receive extra attention in the matter
MANUAL FOR SUGAR GROWERS. 53
of ploughing or forking to assist in undoing the harm done by compressing the soil and thus de- stroying its good condition.
The practice of burning the trash has been advo- cated and followed by some planters, under the im- pression that this renders the mineral constituents of the trash available as plant-food, and more partic- ularly the potash. A moment’s thought willshow the fallacy of such a proceeding. The mineral constitu- ents are present in the trash whether it is burned or no—the act of burning cannot surely be credited with creating the potash, even by anyone ignorant even of the simplest of scientific laws. If the trash decay in the ground, as it will speedily do, the min- eral matters are then as available as plant-food as if the trash had been burned; nay, more so, for owing to the large proportion of silica present in cane-trash much of the potash is rendered insoluble by fusion with the silica to form a kind of glass; the phos- phates, too, are rendered less soluble and so less active by burning. But the loss of the vegetable matter by burning is of the greatest consequence. The importance of vegetable matter in the soil has been so frequently insisted on in the foregoing pages as to require no repetition here. Sometimes, however, if the fields are badly infested with animal or vegetable parasites or diseases, it may be desir- able to burn the trash in order to kill the harmful plant or animal (as various kinds of fungus, termites, mole-crickets, etc.), but this is evidently quite an- other question. Under certain circumstances it may be worth while to suffer some loss by burning
54 MANUAL FOR SUGAR GROWERS.
the trash for some gain in destroying certain pests, and the practical planter will readily discriminate between wise and unwise burning.
It is a common practice for planters to remove the fine mould accumulated in hollows and water- courses and return it to the land. There are several things to be considered in estimating the value of this practice. In the first place it 1s very necessary that ponds and watercourses should be kept from silting up, so that the accumulated mould must be removed at intervals ; in the second place it is de- sirable that the soil washed from the fields should, if possible, be restored to them ; again, it frequently happens that the soil in certain places is shallow, so that increased crops will result if by covering with mould an increased depth can be obtained. Mould obtained from watercourses and ponds often contains a fair amount of plant-food, but not to the extent which planters often think, and thus they frequently overéstimate its value. The following analysis of mould from a watercourse, which was forwarded to the author as an illustration of a good mould, will prove instructive if compared with the analyses of soil given on page 23, when it will be seen that it is deficient in both potash and phosphoric acid.
ANALYSIS OF ‘‘ MOULD,” POUNDS PER MILLION.
21) Ett am eens, Bee ie / = 1,480 | Oxide of manganese ..... 900 Binet Sissies seen. see S.Sou,| Potash <. 7 22 whee ec 41 Macnesis 4.525: coats 1,350 | Phosphoric acid. .....%.° 47 Oxide. OF ION ...3.25 420806) Ag LOU |) REO ROR fie cece sane 1,687
The cost of removing mould and spreading it on the land is often very great, from £6 to £10 per acre
MANUAL FOR SUGAR GROWERS. 55
being prices commonly paid. It appears to the author that money is frequently wasted in this way ; and it would seem best to use mould only when it becomes necessary to remove it for some other purpose than as a dressing for the soil, and to improve the soil by green dressings and better cultivation and manuring ; this course will prove less costly and will be followed by better results, except where it is necessary to in- crease the depth of soil, as in the case where the soil is very thin.
CHAPTER IV.
Manures.—Farm-yard or Pen Manures, their Function and Use. *—Management of Pen Manure.—Open and Covered Pens. — Green Dressing.—Chemical Manures.—Potash, Phosphates, Mineral Phosphates, Superphosphate, Basic Slag or Thomas Phosphate.—Nitrogenous Manures.—Sulphate of Iron.
BRIEF summary of the manures commonly employed by sugar growers in the West In- dies may prove of interest.
The excreta of the various animals kept on a plantation, together with their bedding, constitute one of the most important manures the planter can employ ; this is known by a variety of names, as pen manure, farm-yard manure, etc. There are sev- eral reasons why this is of extreme importance to the planter. It must first be clearly understood that the function of pen manure is a twofold one: on ac- count of the vegetable matter—derived from litter and uneaten and undigested food—which it contains, it is a manure by which condition is maintained, and this is probably its most important function; on the other hand it acts as a fertilizer on account of the nitrogen, phosphoric acid, and potash in it; this fertilizing property is of less importance than the former or mechanical manurial power, for nitrogen,
MANUAL FOR SUGAR GROWERS. 57
potash, and phosphates can be readily and cheaply supplied from other sources.
A curious fallacy exists respecting the action of the animal on the food, and the manurial value of the excreta as compared with the food eaten. It seems to be fully believed by many planters that the excreta have greater manurial value than the food. Nothing could be further from the truth. If all the excreta of an animal which had ceased grow- ing were collected, the manurial value of these would be just equal to that of the food ; there might be a little difference in the rapidity of the action, but the ultimate effect would be the same. How impossible it is to collect all the excreta will be immediately recognised. In the case of a growing animal the ex- creta will contain less potash, phosphates, nitrogen, etc., owing to the retention of these by the animal in order to build up new tissues in the form of bone, muscle, fat, etc. The following tables are taken from Mr. Warington’s “Chemistry of the Farm,” and are based on the experiments conducted at Rotham- sted.
NITROGEN IN ANIMAL PRODUCE AND VOIDED AS URINE, FOR 100 CONSUMED AS Foop.
Obtained as | Voided as | Voided as
carcase or| solid ex-| liquid ex- In total ex-
milk. crement. crement, ees Fattening oxen ...... 3.9 22.6 73.5 96.1 Fattening sheep...... 4.3 16.7 79.0 95.7 Fattening pigs ....... 14.7 22.0 63.3 85.3 MATING COWS J. 2.0.26. 24.5 18.1 57.4 75.5
58 MANUAL FOR SUGAR GROWERS.
AsH CONSTITUENTS IN ANIMAL PRODUCE AND VOIDED, FOR 100 CONSUMED AS FOoopD.
Voided in excre-
Obtained as live ments and per-
weight or milk.
spiration. Patiening oxen x's. .2.5 202 ante 2.3 97.4 Fatienine sheep: 7. % <.-sese ce eee 3.8 96.2 Patienine pigs. 2. ieis.c's0'se ene e ee 4.() 96.0 NEP COWS ee oe om eat eee OS 10.3 89.7
In these experiments very great care was taken to avoid loss of any kind,—such precautions as are im- possible in agricultural practice. The following ac- count of another series of experiments is taken from Dr. Griffiths’ treatise on manures, p. 39:
“ The Muntz-Girard Experiments.—Drs. A. Muntz and C. Girard (‘ Annales Agronomiques,’ tome Xi, 429-436) have performed a series of well-conducted experiments to establish the proportions of the ni- trogen of foods stored up in the increase of live weight, that recovered in the manure, and also the proportion of nitrogen lost. The food given was weighed and analysed, the increase of live weight or the quantity of milk yielded during the experiments were noted, and the manure carefully collected and analysed. The following results were obtained :
Kilograms. Per cent. Nitrogen feonsumed +): 5-05-5554 £ 22%. < 21.817 Nitrogen converted into flesh ....... 4.3000 21.7 Nitrogen recovered in manure ...... 5.588 19.72
Wiirogen lost... Svuas tossed, Seemee 12.129 55.58
MANUAL FOR SUGAR GROWERS. 59
The experiments were conducted with thirty-two sheep kept in a fold with asphalt floor, so as to pre- vent loss of manure. Some of the loss of nitrogen is due to the escape into the atmosphere of ammo- nium carbonate.
“ Muntz and Girard fed two Normandy cows each with 53.5 kilograms of lucerne and 49 kilograms of water daily. Hach cow furnished 33 kilograms of solid excreta and 18 kilograms of urine. The weight of the animals increased by 15 kilograms during the experiments, and they yielded 361 litres of milk. With these cows the quantity of :
Kilograms. Per cent. Murofen consumed. .. 22... 5.060% 14.146 Nitrogen assimilated as flesh ....... 0.544 Nitrogen assimilated as milk........ 2.560 21.95 MrOLeW 1 MANUTC. ...,. . sos. sees: 7.461 52.75 BREGECH AOSt. 5. 0210 oSem «nso oie ss 3.081 25.30
The loss of nitrogen is much less than in the case of sheep, due to the fact that the fermentation of cow’s dung is less active, therefore less ammonium carbonate is formed.
“From these experiments it will be seen that farm- yard manure does not return to the soil all the nitro- gen which was originally extracted from it by grow- ing crops. A portion goes to form flesh and milk, and another portion is lost in the form of ammonia.”
From these experiments it will also be seen that pen manure is of somewhat less manurial value than the combined food and bedding from which it is de-
60 MANUAL FOR SUGAR GROWERS.
rived, even when preserved with the greatest care. It seemed necessary to the author to emphasise this statement, as he has so frequently heard planters talk of “ keeping cattle to make manure,” and heard objections to the use of tramways on sugar estates on the ground that the lack of pen manure under such a system would be fatal to successful manage- ment; and he has seen almost daily vegetable matter carted long distances to put into the cattle-pens when it should have been ploughed into the land on or near which it grew.
One important point of difference between farm- ing in the tropics and in temperate climates may here be insisted on. In temperate climates it is desirable to have the farm-yard manure in a well- rotted state, in order that it shall act quickly when placed on the land. In the tropics decay takes place so rapidly that the rotting of the manure be- fore application to the land is almost, if not quite, unnecessary ; if this is recognised a considerable saving will result.
Of course, a certain quantity of pen manure must necessarily be produced from the ordinary working of a sugar estate. This is extremely valuable and should be preserved with all possible care. But to endeavour by forced means to ‘make manure” is a wasteful fallacy. The author’s advice is to make the health and comfort of the animals the first con- sideration, giving them the most suitable food ob- tainable and adding enough litter for bedding to keep the pens dry and sweet; to apply this manure as quickly as possible, in good quantities at a time,
MANUAL FOR SUGAR GROWERS. 61
to the land in preparation for planting ; and to thor- oughly manure with green dressings all land not manured with pen manure.
The value of pen manure depends very largely on the manner in- which it has been kept. Fresh ma- nure has the highest manurial value, as, in rotting, a certain amount of nitrogen is lost, even under the most favourable conditions. If, in addition to rot- ting, the fluids from the manure-heap are allowed to drain away, then the loss becomes very great, as the nitrogen and potash are found largely in the fluid portion. If the heap be exposed to rain, so that every shower washes out the soluble portion, the loss may become so great as to render the remain- der of little value as a fertilizer. -Where possible, it is desirable to use pen manure as quickly as it is produced, and it has been shown that this can be done more readily in the tropics than in temperate climates. However, it frequently happens that the manure cannot be applied to the land directly, but must be kept for some time; and the value of the resulting manure largely depends on the way in which it is kept. In the West Indies it is the prac- tice to herd the cattle at night in uncovered pens, into which large quantities of vegetable matter——in the form of cane-tops for food, and trash for litter— are thrown, so that a layer of manure of consider- able thickness is soon formed. In many instances the drainage—and with the heavy rainfall of the tropics this is usually abundant—runs away with- out any attempt being made to preserve it; hence a large proportion of the nitrogen and potash is lost,
62 MANUAL FOR SUGAR GROWERS.
the remaining manure acting chiefly as a mechanical agent and possessing but little fertilizing power. When these pens are made in the fields, as frequent- ly happens, it is advisable to lead the drainage from the pens in such a manner that it may flow over the land, and not find its way directly to the drains. A little care in this direction will prevent a great deal of waste which otherwise occurs. In the case of un- covered pens, not in the fields, it is well to have a catch-pit into which the drainage from the pen may run. The contents of this may be distributed upon the land at intervals. It is true that it is difficult to prevent the catch-pit running over in wet weather, so that this method only effects a partial saving at best ; but still it is easily and cheaply carried out.
Covered pens are to be recommended, as by this means the manure is kept dry and free from drain- age. It is no uncommon sight to see a cattle-pen half covered, and yet no provision exist to prevent the water running from the roof into the pen, when a small outlay for spouting would prevent the loss of much of the fertilizing portion of the manure- heap.
During the process of fermenting or rotting, the vegetable matter becomes converted into humus, and the nitrogenous portions into ammonia and ultimately into nitrates. If the fermenting heap become too hot—above 150° F.—there is consid- erable loss of nitrogen, and the heap should be watered with the fluid collected in the catch-pits. If the amount of vegetable matter or litter in the heap is too small—not a common danger in the
MANUAL FOR SUGAR GROWERS. 63
West Indies—there is some risk of loss of am- monia, and this condition is recognized by a strong smell coming from the heap. This may be cor- rected by adding more litter and covering with soil. The addition of soil to the pen from time to time is to be recommended, as soil is a useful agent in fix- ing ammonia.
The food upon which the animals are fed has a ereat influence on the value of the manure ; indeed, in purchasing food-stuffs the farmer also largely takes into consideration the value of the resulting manures, and may be said to purchase his artificial manures in the form of food-stuff. This method of working is economical where cattle are raised for the sake of their milk or for the market, and the manure is carefully preserved, but becomes less eco- nomical in the case of sugar estates where cattle are used for draught purposes, with some necessary loss of manure, and where the system of keeping the ma- nure is faulty. The sugar plantation too, if well worked, will provide all, or nearly all, the food re- quired for its stock, and thus the importation of concentrated chemical manures becomes the most economical method of working. The following table, composed by Sir J. B. Lawes and Dr. Gilbert in 1885, gives the theoretical value of manure pro- duced from the consumption of one ton of certain foods :
64 MANUAL FOR SUGAR GROWERS.
Oats .o2duee s ainale ie eee Ee I Re oN oe £1910 W h@ate oo 4.e ts cesee eer hae tee ibs este Lo ety oe es ste nee SA ae ee 1. 0 oe Hay (clover). ..2. se -- op 8 ae tie Ae 2 i Hay: (qHeadow) .\.. cy se o> winless oe Sw ewe wes 1 C= ae Mangels tuto Ache ee ee 5 eee teas eee 8, 70 Turnip Waite) oo tec eee cine sr eas)» Se 4 0
In the following table analyses of farm-yard ma- nure by various chemists are given:
COMPOSITION OF FARM-YARD OR PEN MANURE PER 100
PARTS. HARRISON. VOELCEER. - | WARINGTON. ANDER- A Covered Average com- field pen. | Fresh. | Rotten. position. pen. f ai MoIstnre 255. >2-ee- | 49.89 45 .64 66.17 | 15 .42 72.48 | 65.0 to 80.00 Organic matter*.... | 12.17 23.67 28.24 16.53 13 94 | 15.00 to 30.00 Phosphoric acid ...| 0.14 0.29 0.32 0.45 0.31 0.2 to 0.4 IMC AL Behe oss 0.95 0.72 1.19 1.78 0.59 Magnesia .......... sata rae 0.15 0.14 0.02 Oxide of iron and ALTEIMVTA rs. ose e 15.30 12.61 0.42 0.67 0 45 ROtashy? seen ee 0.11 0.38 0.58 0.58 0.32 0.4 to 0.7 * Contains a 0.22 0.35 0.64 ? 0.38 0.40 to 0.65
In applying pen manure to the land it is neces- sary to cover it thoroughly; this is best done by ploughing it in or by covering it during the process of raising the banks or “holeing:” unless it is buried its condition-giving or mechanical action, the importance of which must be recognized, is not fully exercised. The quantity to be applied should be about twenty tons per acre.
Where the quantity of pen manure produced on an estate is insufficient to cover the whole area to be planted, that portion receiving no pen manure
MANUAL FOR SUGAR GROWERS. 65
should be green-dressed, 7.e., a crop should be grown upon the land and turned in. This has been pre- viously discussed in Chapter II., and it has been shown that plants of the pea and bean tribe (le- guininosce) are preferable for this purpose. When leguminous crops are grown and turned in, there is, as has been said, a-gain of nitrogen; there 1s no ac- tual gain in potash, phosphates, and other mineral matters, though this treatment will bring up mineral matters from below and deposit them near the sur- face in an available condition ; hence green-dressing should be followed by a lberal manuring with the necessary mineral manures, potash, phosphates, and the like.
Amongst the plants suitable for green-dressing may be mentioned the pigeon-pea (Cajanus indicus), woolly pyrol (Phaseolus mungo), Bengal bean. These plants take from three to six months to grow to suf- ficient size to be ploughed in; when they are suffi- ciently developed they are cut down and arranged in rows to enable the plough to open furrows ; the green dressing is laid in the furrows and covered with soil, the banks being raised over the green dressing.
In some cases where the soil is in very bad con- dition it is often expedient to raise a green dress- ing on the banks between the canes, even after the canes are planted and while they are growing. This may be done by planting pigeon-peas, woolly pyrol, or the like, upon the banks as soon after their preparation as possible ; the green crop then grows up with the cane, and, if it be carefully watched, will
9)
66 MANUAL FOR SUGAR GROWERS.
in no way interfere with the growth of the latter. When the green crop has grown as long as is con- sidered prudent, it is cut down or pulled up and buried in the banks by the weeding gangs, who find very little difficulty in accomplishing this. By work- ing in this manner even very stiff clay soils may be got into good condition in a comparatively short space of time. This method of working can only be followed advantageously in a moist season; in a dry season the double crop appears to remove too much moisture, and the cane crop suffers.
In some places seaweed can be readily obtained. This forms a valuable manure when ploughed in ; by this means nitrogen and potash are supplied together with vegetable matter. About twenty or thirty tons per acre form an excellent dressing.
Now as pen manure and green dressings merely return to the soil for the most part potash and phos- phates, ete., derived from the land itself, it follows that as the exported crops carry away certain quantities of various substances forming plant-food the land must be rendered less fertile from year to year, so far as mineral matters are concerned ; hence it is imper- ative that manures supplying potash, phosphates, etc., be imported if fertility is to be maintained. Farm-yard manure alone is insufficient to maintain fertility.
The following brief sketch of some artificial or chemical manures may prove of interest.
Potash Manures.—Formerly potash salts were ob- tained entirely from the ashes of plants: in coun- tries where forests prevail, as in North America,
MANUAL FOR SUGAR GROWERS. 67
Russia, Sweden, etc., large quantities of wood are burned for the sake of the ash; the potash is ex- tracted from the crude ash by solution in water, and recovered by evaporation to dryness, the potash being thus obtained as carbonate. Of late years ex- tensive mineral beds of salts containing large quan- tities of potash have been discovered in Germany, and it is from this source that the potash used for manurial purposes is chiefly obtained. One of the most important of these minerals is kainit, a sub- stance containing sulphates of potash and magnesia together with common salt and other substances. A good sample of kainit should contain twenty to thirty per cent. of sulphate of potash; from this substance sulphate of potash in a comparatively pure state can be extracted, and where, as in the case of the West Indies, the manures have to be trans- ported long distances, it is found more economical to purchase the purified and concentrated form of sul- phate, although the first cost is higher. Thus, with freight at £2 per ton, if kainit containing twenty- four per cent. of sulphate of potash were purchased, the cost of the sulphate of potash would be increased by £8 per ton, while with purified sulphate of ninety- six per cent. the increase in cost is only a little over £2 per ton. This forms a very good illustration of what has been said before, namely, that in the West Indies it is economical to purchase manures in as con- centrated a form as possible, and thus the use is de- nied to the planters of many forms of manure which in some countries are economical and useful. Another mineral containing potash, and which is
68 MANUAL FOR SUGAR GROWERS.
often employed as a manure, is carnallite. This contains chloride or muriate of potash and chloride of magnesia. It is found, however, that it is pref- erable to employ potash salts in the form of sul- phate rather than chloride, hence carnallite is not a manure likely to attract the attention of sugar- cane growers. Amongst the manures obtainable locally, wood ashes, leaves, etc., and urine are rich in potash, and should on no account be wasted.
Practically, then, the best form of potash manure to import is the sulphate ; this can now be obtained of a very high degree of purity. A guarantee as to the amount of potash it contains should always be required.
Phosphatic Manwres.—The first phosphatic ma- nure employed was bones, and bones are used at the present time when itis necessary to employ a phos- phatic manure whose action shall extend over a long period. Raw bones contain about forty to fifty per cent. of phosphate of lime, and if they have been steamed or boiled to remove the gelatine, the quantity of phosphate of lime is raised to about sixty per cent., while the nitrogen, of which there is about four per cent. in raw bones, is reduced to about one- fifth per cent. Bones being very insoluble and thus requiring a very long time for their disintegration, a method was devised by Liebig by which they could be rendered soluble and so caused to act more quickly. He suggested the treatment of the bones with sulphuric acid. By this means an acid phos- phate of lime is formed, together with sulphate of lime, or gypsum, and this in a little time forms
MANUAL FOR SUGAR GROWERS. 69
a dry mass which can be ground, and is then ina very suitable form for use as manure. Phosphate of lime submitted to this process is known as super- phosphate. |
Phosphate of lime suitable for conversion into superphosphate is found very widely distributed in nature, in the fossilized remains of animals and their excreta; of this character are the coprolites of the eastern counties of England, the phosphate beds of Sombrero, Aruba, Florida, Canada, ete. These mineral phosphates are found in various de- erees of purity—from those containing seventy or eighty per cent. of phosphate of lime down to those containing a mere trace.
Good superphosphate should contain fifteen to twenty-four per cent. of the soluble or mono- or acid- phosphate of lime, as it is variously termed, equal to about twenty to thirty-two per cent. of in- soluble or tri-calcium phosphate rendered soluble.
Finely ground mineral phosphates are sometimes used without being treated with acid; it is neces- sary that the substance be used in a state of very fine powder. In this condition good results have been obtained in the case of the sugar-cane. If lime be added to superphosphate, the mono-calcium phosphate is reconverted to tri-calcium phosphate. This is sold under the name of precipitated phos- phate. Ground mineral and precipitated phos- phates, from the fact that they are not acid, are well suited for soils containing but traces of lime.
Intermediate in character between natural ma- nures and mineral phosphates are the manures known
70 MANUAL FOR SUGAR GROWERS.
as guanos; these for the most part consist of the excrement of various birds. Guanos vary in com- position according to the length of time they have been deposited, fresh guano closely resembling farm-yard manure in its general character, except that it is extremely concentrated from the absence of litter; hence, guano of this type is a general manure, supplying nitrogen, phosphate, and a small quantity of potash. In the older guanos the am- monia has largely disappeared, so that these gua- nos are essentially phosphatic in their nature. Ni- trogenous or ammoniacal guanos are becoming less and less abundant, so that much of the manure sold under the name of guano is a manure artificially compounded, usually being of excellent quality and preferable to raw guano.
There is one form of phosphatic manure which, so far, has received but little attention from West Indian planters,—basic slag, basic phosphate, or Thomas phosphate, as it is variously termed. In the manufacture of steel from cast iron some diffi- culty was experienced, owing to the presence of phosphorus in the iron. It is found possible to re- move this by the use of lime, from which results the basic slag, a substance containing the phosphorus in combination with the lime as basic phosphate of lime. This substance contains from fifteen to twenty per cent. of phosphoric acid, equal to about thirty-four to forty-five per cent. of tri-calcium phos- phate ; hence, it is more concentrated than super- phosphate. Jt is not an acid manure, as super- phosphate is, and on soils deficient in lime, as so
MANUAL FOR SUGAR GROWERS. 7
many sugar soils are, there appears to be some ad- vantage in this. It is very essential that basic phosphate be used in the state of the finest powder ; when rubbed between the fingers, it should feel al- most as smooth as flour. A guarantee of the quan- tity of phosphoric acid which it contains, and of its degree of fineness, should always be obtained from the vendor. This manure is cheaper than super- phosphate. It can be stored without loss or deteri- oration for any length of time, and, as it is not acid, does not destroy packages as superphosphate does, whereby some loss of superphosphate is frequently incurred. It appears, therefore, well worthy of careful trials in the cultivation of the sugar-cane. The author has trial- plots manured with basic phosphate under observation, and the results ap- pear highly satisfactory.
Nitrogenous Manures.—The chief nitrogenous manure used in sugar-growing in the West Indies is pen manure, and this is frequently increased in richness and value by feeding the stock on oil-cake. In a very few instances oil-cake has been applied direct to the land and serves as excellent manure. In districts—as in portions of the United States— where cotton-seed cake is easily and cheaply ob- tained, the plan of using oil-cake direct as manure may perhaps be followed with advantage, but in the West Indies such a course is hardly likely to prove economical, and cake is best used as food.
Practically the only nitrogenous manures it pays to import are nitrate of soda and sulphate of am- monia. These, from their concentration, are very
72 MANUAL FOR SUGAR GROWERS.
economical, the former, when pure, containing 16.4 and the latter 21.3 per cent. of nitrogen; hence the expenses in handling are reduced to a small amount, the point to be considered in colonial agriculture.
Nitrate of soda is found as a deposit in certain parts of South America where the rainfall is ex- tremely limited ; it is found mixed with clay, gypsum, and other impurities, and is purified by dissolving out the nitrate with water and recovering the nitrate by evaporation. Good commercial nitrate of soda as employed for manures usually contains from ninety-five to ninety-eight per cent. of real nitrate of soda. This manure is, as will be seen from what has already been said upon the subject of nitrifica- tion, a quick-acting one. It must be remembered that the soil has no retentive power for nitrates, hence in wet seasons or on wet lands there is great liability to loss from drainage.
Sulphate of ammonia is obtained from the am- moniacal liquor produced in the manufacture of coal- gas; it usually occurs In commerce in a very pure state, containing from ninety to ninety-eight per cent. of real sulphate of ammonia. It 1s sold on the basis of the ammonia it contains; thus twenty-four per cent. of ammonia is equal to ninety-three per cent. of sulphate of ammonia, while twenty-five per cent. of ammonia is equal to about ninety-seven per cent. of sulphate of ammonia. Like all chemical manures it should be purchased on the basis of analysis. Sulphate of ammonia is the most satis- factory nitrogenous manure the sugar grower can import; it should be employed as a top-dressing in
MANUAL FOR SUGAR GROWERS. 13
small quantities at a time, to obtain the best results ; about one hundredweight per acre being a conve- nient quantity.
Ferrous sulphate, or sulphate of iron, is attracting some attention as a manure: the author has several trial plots laid down this 1891-92 season. In one experiment last season there was a most marked dif- ference in the appearance of the canes manured with this substance; throughout the whole period of erowth they were greener and taller than the ad- joining canes—part of the same field—not manured with sulphate of iron, but otherwise similarly treated. Unfortunately, accurate quantitative results were not obtainable, but, as far as could be ascertained by weighing the canes from one-fifth of an acre from each plot, there was an increase of six per cent. in the weight of the canes in favor of the sulphate of iron, and this on second ratoons in a very dry season. The individual canes, too, from the sulphate of iron plot were finer looking. 'The juice from the canes manured with sulphate of iron and those not so treated was carefully analysed to discover if the iron exerted any influence on the juice ; no difference could be detected. The figures obtained are given below.
Cane-sugar.| Glucose. Giucee Pounds per Gallon: Pounds. Juice from canes with sulphate iron.... 2.04 0.0378 1.85 Juice from canes without sulphate iron. 2.04 0.0373 1.83
*
These results agree within the limits of analytical error.
14. MANUAL FOR SUGAR GROWERS.
Sulphate of iron should be purchased in fine crystals or powder, and should be applied as a top- dressing in quantities not exceeding one hundred- weight per acre. Many sugar soils are deficient in soluble iron; under this circumstance the use of sulphate of iron is likely to prove beneficial.
No attempt is made here to discuss those manures not likely to be met with in the West Indies. In districts where manufacturing operations and the like are carried on, various waste products are obtained which are often of value as manure, but too bulky to admit of shipment to a distance ; hence they are not referred to here. Nor is any attempt made to com- pare or contrast the merits of the many manures specially compounded for sugar soils; most of these are composed of mixtures of the various substances herein referred to, and as a rule are skilfully pre- pared and of good money value.
It is important to remember that artificial manures can only exert their full action on soils in good con- dition. To apply artificial or chemical manures to land in bad condition is a most wasteful proceeding, and one likely to lead to results discouraging to the experimenter and to the discredit of scientific manur- ing generally. Again, it must be remembered that artificial manures must be used in such a manner as will pay ; it is quite possible—nay, easy—to employ these manures in excess, and thus to spend more money on the manure than the increase of the crop will pay for. Artificial manures are in most cases ab- solutely necessary. They are costly, hence their use calls for the exercise of a considerable amount of skill.
CHAPTER V.
Cane-mills.—Three-roller Mill.—Fletcher-Le-Blane Four-roller Mill.—Mirlees’ Four-roller Mill.—Skegels’ Mill.—De Mornay Mill.—Hydraulic Attachment, ete. —Double Crushing. —Ma- ceration.—Diffusion.
HE usual method of extracting the juice from the cane is to crush the canes between the rollers of various forms of cane-mill. The mills most commonly employed have three rollers, one roller being on the top and pressing on the two be-
neath, as in Fig. 8. The canes enter between A
Fie. 8.—Diagram of three-roller mill.
and B, the feed rollers, and emerge between B and C, the megass roller. The distance between A and B is so arranged that the canes shall enter with sufficient freedom to ensure good feeding, and at the same time be subjected to a certain degree of pressure, while B and C are set as closely to- gether as possible, leaving only sufficient space for the escape of the fibrous portion of the cane—the megass, or begass, as it is called. Skill is required in adjusting the rollers so as to secure as perfect
76 MANUAL FOR SUGAR GROWERS.
crushing as possible, and yet not endanger the safety of the mill by straining or breaking it from over- pressure. In the space between the rollers A and C is fixed a bar or plate-—the trash-turner, or dumb returner, which serves to direct the crushed cane between the rollers B and C. The mass of crushed canes sometimes becomes jammed between the dumb returner and the rollers, leading to stop- page, and sometimes even to breakage, of the mill. Hence efforts are being made to construct mills in which the use of a dumb returner is dispensed with. Other mills are constructed with four or more rollers. Many kinds of mill have been designed, for each of which some special advantage has been claimed. Many of these are simply of the ordinary three- roller type, with various modifications in their con- struction to afford greater strength or security.
Fie. 9.—Diagram of Fletcher-Le Blanc four-roller mill.
Among those calling for special comment may be mentioned Fletcher & Le Blanc’s four-roller mill, in which the cane is submitted to three crush- ings, as will be seen from the diagram, Fig. 9.
MANUAL FOR SUGAR GROWERS. 1
This mill is fitted with two dumb returners, which are hollow, to admit steam or water being forced into the megass, so as to combine the advantages of maceration with effective crushing.
In Mirlees’ four-roller mill the cane is only submit- ted to two crushings, but from the construction of
Fig. 10.—Diagram of Mirlees’ four-roller mill.
the mill these can be made very effective, Fig. 10. This mill has no dumb returner. There is a dis- position in some quarters to prefer mills of this type in which the rollers work in pairs, each pair only crushing once, instead of three rollers giving three crushings, as in the ordinary three-roller mill. Messrs. Thompson & Black’s auxiliary rollers, which can be fitted to any ordinary mill, are worth the attention of those whose mills are in fair order, but not powerful enough to give high expression. The mill invented by Mr. Skegels, of Demerara, is attracting some attention, and reports of its work- ing power are looked forward to with interest. It is a modification of the three-roller mill, and is without a dumb returner,* having besides some new features in its construction. In the De Mornay mill (Fawcett,
* A revolving bar or small roll is now added to take the place of a dumb returner.
78 MANUAL FOR SUGAR GROWERS.
Preston & Co., Liverpool) the trash turner is dis- pensed with. The mill has four rollers, two of which are large and two are small. The construction of
the mill will be easily under- stood from the diagram, Fig. oe “
It would appear that dis- Fie. 11.—Diagram of De Mor- pensing with the dumb re- nay mill. Saree
turner, and obtaining three
distinct crushings of increasing power, the final one
from the heavy rollers is an important advance in
mill construction. Mills of the De Mornay type will doubtless find increasing favour in the near future.
Another important improvement in the construc- tion of cane-mills consists in holding the rollers in place by flexible, instead of rigid, supports. In the older mills the rollers were held in place by means of screws passing into the framework of the mill, so that the rollers were kept almost inflexibly in one position—the result being that if anything, either cane or some foreign body, were forced into the mill in such quantity that it could not pass between the rollers, the mill must either stop—choke as it is termed—or something must break. It thus be- comes a question of relative strength of mill and engine.
In improved mills the rollers are kept in place by what is known as the hydraulic attachment. This consists of a simple modification of the ordinary hydraulic press. It is well known that if pressure be applied to a fluid, the pressure is transmitted
MANUAL FOR SUGAR GROWERS. 79
equally in all directions, and thus if in any one place a pressure of say one ton per square inch be applied, then a pressure of one ton per square inch will be exerted at ev-
ery part of its surface. IH, a
then, weights be applied to the fluid in the vessel |
A until the pressure is one ton per square inch, and F the vessel A is connected
with a second vessel, B, by Fie. 12.—Principle of hydraulic means of a pipe, then ev- ae
ery part of the sides of the vessel A, of the pipe, and of the sides of the vessel B, will also be subjected to a pressure of one ton per square inch. Now, if in B there be a piston moving freely, the piston, too, will share the pressure. Suppose the area of the piston to be twelve square inches, then the piston will have a pressure of twelve tons exerted upon it. H, now, the piston be made to press upon the rollers, the
Fig. 13.—Diagram of hydraulic attachment to cane-mill.
rollers will be thrust forward with a pressure of twelve tons. How this is applied to the cane-mill will be seen from the diagram, Fig. 13; from which
80 MANUAL FOR SUGAR GROWERS.
it will be seen that with a piston at each end of the roller, and with the pressures mentioned, the roller so fitted will be held in its place with a pressure of twenty-four tons, no more and no less, so that no ex- tra strain can be put upon the mill by over-feeding or by a foreign body, such as a stone. Hence the dan- ger of breaking is reduced toa minimum. And what is quite as important, the same pressure of twenty- four tons is exerted upon whatever is between the rollers, whether much or little, so that the same pressure is exerted whether the mill is only partially filled with canes or when fed full. Those who have carefully watched how the crushing varies with the feed in a mill not provided with the hydraulic at- tachment will at once see the value of this flexibility with unvarying pressure.
Various devices have been arranged to apply springs in the place of the hydraulic press; some of these are very useful and easily attached to exist- ing mills, and from their simplicity they have much to recommend them.
It is usual to speak of mills as expressing so much per cent. of the weight of the cane in the form of juice ; it is well at the outset to see that this is an unsatisfactory method of statement, as canes will vary very much in the amount of juice which they contain, so that the same mill might express, say 65 per cent. from one lot of canes, and only 60 per cent. from another. A better method would be to ascertain the quantity of moisture left in the me- sass. This should vary less than the quantity of juice expressed.
MANUAL FOR SUGAR GROWERS. 81
How important good crushing is to the planter will be seen in a moment from the following figures : If one mill expresses 55 per cent. and another 70 per cent. from the same canes, then the gain 1s fif- teen on every fifty-five, or 26.1 per cent. The aver- age expression of what are regarded as fairly good mills in the Leeward Islands is probably not over 60 per cent.; the possible expression is certainly not under 75 per cent. ; in other words, over 25 per cent. of the sugar now grown, and which with good machinery could be extracted, is at present thrown away. It is evident that this condition cannot last in these days of keen competition.
In large factories it is the practice to resort to double or even triple crushing ; two or three mills are arranged one behind the other, the canes being thus submitted to two or three grindings. It is usual to blow steam into the megass in its passage from one mill to the other; by this means the ex- traction of sugar 1s increased. This would appear to be due to two causes: one, the dilution of the cane-juice, and the remaining moisture therefore containing less sugar; the second, that the cooking resulting from the use of steam or hot water coagu- lates the albuminous matter of the cane, and thus facilitates the expression of the juice.
It may be worth while briefly to sketch out here the principles on which the diffusion process of extracting sugar from the cane is based. Those who are interested in the practical application of the process will find abundant information in the cur- rent literature of the sugar industry, as in the
82 MANUAL FOR SUGAR GROWERS.
“Sugar-cane,” “The Louisiana Planter,” “Sugar,” ete.
It has already been shown that by means of the process known as osmose (see page 9) certain sub- stances—namely, those capable of existing in a crys- talline form—can pass through vegetable membranes when those membranes are in contact with water on both sides.
Now, if thin slices of sugar-cane are placed in water, we have the vegetable membrane of the cell- wall separating water from the solution of sugar and other matters in each cell; consequently the sugar of the cell, being crystallisable, finds its way through the cell-walls into the water, and the greater part of the impurities, being non-crystalline, is left behind. By repeated treatment of the chips with fresh water, the whole of the sugar is removed.
In practice this is carried out by slicing the canes by means of revolving knives, and placing the result- ing chips into large vessels into which hot water can be forced; the vessels vary in number from six to twenty, and are arranged either in a circle or in parallel rows. When the water has been in contact with the chips for a given time, it is drawn off. In order to effect complete extraction of the sugar, the water—or, as it may now be termed, diffusion- juice —is drawn down upon a fresh lot of chips, and another charge of water or weak diffusion-juice is run upon the partially exhausted chips. The juice in this way passes through all the diffusion- vessels in turn, water entering at one end of the series, and strong diffusion-juice being drawn off
MANUAL FOR SUGAR GROWERS. 83
at the other. The following diagram will help to make this clear :
EXHAUSTED CANE CHIPS
Fig. 14.—Diagram of diffusion-battery.
A, B, C, D, E are five diffusion -vessels. E has just been filled with fresh chips, while the chips in A are nearly exhausted. Hot water is forced into A, thence it passes into B, then into C and D, and finally comes in contact with the fresh chips in E, after which it is drawn off to the evaporators. The | chips in A, being now exhausted by the fresh water, are discharged, and the vessel, refilled with fresh chips, now becomes the last of the series, the fresh water entering at B, and the diffusion-juice drawn off at A, and so on, each vessel becoming alternately first and last of the series.
The question whether diffusion is to supersede crushing is one which is being most vigorously dis-
84 MANUAL FOR SUGAR GROWERS.
cussed ; the chief points for and against the process may be briefly summed up as in the table.
ADVANTAGES. | DISADVANTAGES. Complete removal of sugar. | Difficulty in slicing canes. Greater purity of juice. Process and machinery com-
plicated.
Juice being diluted, cost of evaporation increased.
Chips, being saturated with water, are unfit for burning without drying, hence ill adapt- ; ed for fuel.
So far as the smaller sugar-growing colonies are concerned, diffusion at present appears to be quite out of the question. Even where it has been tried on a large scale in the West Indies its success has been in several cases problematical. Double or triple crushing is for the present the safest line on which to advance when all the circumstances influencing sugar growing in the West Indies are taken into account. This is no place for a lengthy discussion of the merits of diffusion as compared to crushing, and this brief outline must suffice.
CHAPTER VI.
Cane-juice.—Composition.—Tempering.—Use of Lime.—Phenol- Phthalein Test for Lime. — Clarifying. —Formation of Scum.— Treatment of Scum.— Filter-presses.— Composition of Filter-press Cake.—Uses of the Cake.—Value of Cake.
HE eane-juice as it runs from the mill may be regarded as a solution of sugar in water, with — various impurities. It varies considerably in com- position according to the variety and ripeness of the cane, the soil, the season, whether wet or dry, and numberless other circumstances. A fair sam- ple of cane-juice will contain about
Per cent. MG UMN MET AD 5 a yov'ais ais 2 onal sidie. 3: SaaS aoe Pe aD RGIGECOSEP Er ishel Vora fare tess! oc, os leialoe ET ee ee m9) Miameral Maiter ey. stsyaas S< wis chs ote Sha asta hoes 3 Organic Matter other than Sugar............. a DVabeie Stoic se Sos See clon ocean sete 81.0 EUGENE ecto. arch lteter n oe eae eae aoe o state ce Sere 100.0
The organic matter other than sugar consists of albumen, fat, wax, colouring matter, and a variety of - substances the properties of which are but little understood.
The juice is received into vessels termed clari- fiers. These in the case of windmill estates are placed over the flues leading from the battery, and are thus heated by direct firing. On estates possess- ing steam plant the exhaust steam from the engine
86 MANUAL FOR SUGAR GROWERS.
is led into a steam-jacket surrounding these vessels, so that the juice is made hot as quickly as possible. Cane-juice is always slightly acid, so, as soon as the clarifier is about one-third or half full, a quantity of slaked lime, made into a thin cream by mixing with water, is thrown in, and the lime kept in slight excess until the clarifier is nearly full. When the clarifier is full the contents are vigorously stirred, and the quantity of lime carefully adjusted. This operation is known as tempering; its effect is to neutralise the acidity of the juice and to cause the precipitation of the greater part of the impurities.
Until recently this final adjustment of the quan- tity of lime was left to the unaided judgment of the workman in charge of the clarifiers. Consequently there was great irregularity in the manner in which the lime was used, sometimes an excessive, some- times a deficient quantity being employed. Asarule an insufficient amount was used. The sugar thus produced of course varied considerably in quality. - After a number of experiments, the author, in an article contributed to “Sugar,” April, 1890, sug- gested a method of working which is now very gen- erally followed on-estates making muscovado sugar, with satisfactory results. The article is here repro- duced :
“When using lime for the purpose of neutralising the juice of the sugar-cane and thus causing the pre- cipitation of the albumen, some means of ascertain- ing with precision when sufficient lime has been added is highly desirable.
“To meet this requirement Dr. John Shier, many
MANUAL FOR SUGAR GROWERS. 87
years ago, devised a method of testing based on the use of litmus-paper as an indicator of the point of neutrality. It is found, however,—and Dr. Shier’s directions for using his test contain a tacit admis- sion of this fact,—that litmus-paper does not afford acorrect indication of the point of neutrality in cane- juice ; hence the test had to be supplemented by observations of the manner in which the flocculent precipitate of the juice separated. This complicates the working of the test and greatly impairs its use- fulness. That litmus is not an accurate indicator in the case of organic acids is perfectly well known, and certain other bodies are now largely used in the laboratory in place of it.
“These considerations led the writer to make a series of experiments with other indicators, when it was found that phenol-phthalein could be em- ployed with ease and certainty, and that it could be placed in the hands of the workmen in charge of the clarifiers, who quickly acquire the small degree of skill necessary for its successful use.
“The following are required for making the test: test-tubes, a pipette, and a drop-bottle containing a solution of phenol-phthalein in spirit; and the method of testing is as follows :
“ The clarifier is filled with juice, and lime added in the usual manner. When the greater portion of the lime required has been added, a little of the juice is taken from the clarifier by sucking it into the pipette with the mouth ; two of the test-tubes are about half filled with juice from the pipette, and one or two drops of the phenol-phthalein solution are added to
*
88 MANUAL FOR SUGAR GROWERS.
one of them. If sufficient lime has been used the addition of the phenol-phthalein solution will cause a slight change of colour to pink ; if the quantity of lime is insufficient there will be no change of colour ; in this case a little more lime must be put into the clarifier, care being taken that it is well mixed, and afresh portion of the juice put into the tubes and tested as before; and this must be repeated until a very faint pink coloration is obtained. If too much lime has been used the addition of the phenol-phtha- lein solution will cause a strong pink to red colour- ation, and in this case the excess of lime must be corrected by adding a sufficiency of fresh juice until, on applying the test, only a faint change of colour is observed.
“This method of working has been employed successfully on several sugar estates, resulting in much more uniform work than has hitherto been obtained ; it is also found that juice thus tempered eives very little scum in the subsequent process of evaporation, Inversion is checked, and consequently the yield of molasses is lessened.
“To prepare the test solution, about ten grains of phenol-phthalein are dissolved in about half a pint of alcohol, white rum, or high-wines. The alcohol being frequently slightly acid, the acidity is neutral- ized by adding lime-water drop by drop to the solu- tion until a faint pink colour makes its appearance and remains permanent. This faint colour is next destroyed by adding a small quantity of spirit until the colour just disappears ; with good spirit the use of lime-water to correct acidity is unnecessary.”
MANUAL FOR SUGAR GROWERS. 89
It may be added, as the result of longer experi- ence, that it is a common fault, when using phenol- phthalein for the first time, to add too much lime, thus obtaining a decided red instead of a faint pink colour when testing in the manner described. It is very important to avoid this. Every clarifier should be tested ; it is not sufficient to test one or two in the course of the day’s work.
Muscovado sugar tempered with the aid of phenol- phthalein, taking care that only the smallest excess of lime is used, is firm and hard, delivers its mo- lasses freely, and is usually somewhat dark with a ereenish-grey colour easily recognized ; this colour is easily removed in refining,—far more easily, in fact, than the colour of under-tempered sugars, which frequently have a red tinge.
The quantity of molasses produced is greatly re- duced when this method of working is adopted, pointing to the fact that under-tempering leads to inversion.
This process has been found of great service to sugar-makers, as they are thus able to work with a degree of precision otherwise unobtainable, and are also able to keep a check on the workman, the pro- cess being rendered independent of the opinion or skill of the man in charge of the clarifiers. The author has received many gratifying accounts of the success with which the use of the process has been attended.
These directions apply to the manufacture of mus- covado sugar: if a light-coloured sugar is required, it is advisable to under-temper somewhat, still using
90 MANUAL FOR SUGAR GROWERS.
phenol-phthalein as a guide ; or, better, to temper as for refinery muscovado, and, after clarifying, to boil to a density of about 20° B., and then subside,—that is, allow the syrup to stand for twelve hours, in or- der that any sediment may fall to the bottom of the tank, the clear syrup being removed by carefully drawing down, leaving the sediment undisturbed. After subsiding, the syrup is made slightly acid by means of sulphurous acid produced by burning sul- phur and passing the fumes into the syrup. (See Chapter VIL.)
Light-coloured sugar may also be made by tem- pering and clarifying in the usual manner, then ren- dering the juice slightly acid with phosphoric acid, various forms of which are now sold for this purpose.
In the analysis of cane-juice on page 85 there appears ‘organic matter other than sugar.” This consists largely of albumen, a substance not unlike white of egg in character. On adding lime in proper quantity and heating this, albumen is thrown out of solution, and, as the liquid becomes hot, rises to the surface in the form of a scum.
It is well to remember why a scum forms. It is due to the fact that the heat drives out of the liquid a certain quantity of the air which the cane-juice contains in solution. The presence of dissolved air in the juice is readily understood if the foaming con- dition in which it leaves the mill is observed: this air as it is liberated attaches itself in little globules to the floating solid particles in the juice, the albu- men, etc., and buoys them up to the surface, where a thick scum is formed. It will at once be seen that
MANUAL FOR SUGAR GROWERS. 91
to obtain a perfect scum it is necessary to leave the liquid undisturbed so that the minute bubbles of air do not become detached from the solid par- ticles.
When the temperature is about five degrees below boiling-point it will be found that the liquid is almost clear, all the floating matter having been carried to the surface as scum. This is the point known as the “cracking point” by the work-people, as at this point the dark upper scum tends to crack and dis- play a white frothy scum beneath. The juice is now ready to be drawn off: if this is done with care, the ereater part of the juice can be drawn off clear, leav- ing a thick scum behind in the clarifiers ; this scum is drawn off into another vessel, to be treated as de- scribed below.
On estates where rum is made, the scum is con- veyed to the distillery and is used in setting up the wash for fermentation: many estates, however, from various reasons, have ceased to make rum, and on these it is desirable to extract as much sugar as possible from the scum; this is done by two methods. The first consists in accumulating all the scum obtained in a day’s working in a steam-heated vessel termed a defecator or scum-heater, and the clear juice is run off from time to time. By keeping the scum until the following morning a considerable quantity of juice can be recovered, the residue af- ter this treatment usually in practice amounting to four per cent. of the volume of the juice obtained from the mill.
In the second method the scum is submitted to
92 MANUAL FOR SUGAR GROWERS.
pressure in bags: at first men bags were filled with the scum and pressed in various modifications of the presses used for cheese or cider making in England ; these, although troublesome, yielded a fair quantity of cane-juice, and if carefully worked and kept clean did good service.
These presses are now entirely superseded by the various kinds of filter-press so largely used in al- most every industry where filtration 1s necessary. The filter-press consists of a series of chambers, usually of iron. Each chamber is lined with a cloth. The substance to be filtered is forced into the chambers until they are all completely filled with compact and nearly dry solid matter, the fluid portion having meanwhile escaped through the cloth into suitable channels provided for it. The cham- bers are thus filled either by means of a pump, or preferably by means of the apparatus known as a monte-jus. This consists of a strong closed iron vessel provided with a pipe passing nearly to the bottom, and leading to the chambers of the press. A second smaller pipe just reaching through the top connects the vessel with a steam boiler. A third opening provided with a stop-cock serves to admit the scum. The scum is run in until the monte-jus is nearly but not quite full; steam is turned on, and the pressure of the steam forces the scum up the outlet pipe into the chambers, the pressure obtained being the pressure of the steam in the boiler. A pressure of from twenty to fifty pounds per square inch is found suitable for the working of filter-presses for cane-juice scums.
MANUAL FOR SUGAR GROWERS. 93
A great many filter-presses are on the market, all based on the principles here stated, but varying - ‘greatly in the details of their construction.
When sugar-cane scums are treated in a good filter-press with a pressure of about forty-five pounds per square inch, a very large quantity of Juice is recovered, and there remains in the press a solid, nearly dry cake, which in practice is about one per cent. of the volume of the juice obtained from the mill. It is thus seen that a good filter- press effects a saving over the first method—where- by four per cent. of residual scum is obtained—of three per cent.
The following analyses of the scum-cake, after drying, will serve to show its general character :
COMPOSITION OF FILTER-PRESS CAKE, PER 100 PARTS.
Harrison. Watts. PSUS IEC a: Lon tan tors aac Nene ciate Aeon 14.76 10.04 Wreamic MACR™ . F. .6ce fe 2 ne Bu 66.93 68.45 mildea, Sad). Cts sso. see lose 3.20 5.40 hesphate of lime... o<..'.<sssas 12.95 13.86 sider Ol TOWNS .: 6661s oc ateejee ee. soe .02 PMU UATE ts 5 <e/8 wiinnaru deareinte Hotes 43 .08 REPORT ik dash Sivas cia Pinte ve a 222 Parte eA oe ajacdaln oemee eke Ag -15 SLUTID OSA ee gee Sa ee as 10 Matter not estimated........... 1.12 1.68
100.00 100.00
SIOoOntalns, MitrOPEM).\.. .)- «ocsesis cece cies 2.07 il oul
The amount of phosphate of lime in the cake de- pends upon the manner in which the operation of tempering has been conducted. If the juice be un-
94 MANUAL FOR SUGAR GROWERS.
der-tempered only a portion of the phosphoric acid is precipitated, and the resulting scum will contain only a small proportion of phosphate of lime; if, on the other hand, the lime be added in sufficient quantity, practically all the phosphoric acid is pre- cipitated, and the resulting scum is rich in phos- phate of lime, as shown in the above analyses.
The quantity of sugar in the fresh cake 1s from two to four per cent., and, as the cake amounts to about one per cent. of the volume of the juice, the loss of sugar in the cake will be about one- fourth per cent. of the total sugar in the juice ; or, say, from three hundred to five hundred pounds-on a crop of one hundred hogsheads; whereas, if the scum thrown away were four per cent., as in the case of the defecator, the loss would be about three and one-fourth hogsheads. These figures will suffice to show the value of a filter-press.
The cake from the filter-press forms excellent food for cattle. The nitrogen present in the dried cake is equal to about twelve per cent. of albumi- noids, being equal in quantity to that contained in such foods as oats and maize, and somewhat less than half that contained in linseed cake, peas, and beans.
When fresh, cattle will eat both the fluid scum from the defecators or the solid cake from the press with avidity. But owing to the rapidity with which it becomes sour, there is danger of produc- ing colic in the animals unless the greatest care is taken. In the case of the defecator scum it is Im- possible to preserve it. Hence, only what can be eaten by the stock at once is of any use as food.
MANUAL FOR SUGAR GROWERS. 95
The remainder is generally run into the lees pond, where it undergoes fermentation, giving rise to most offensive smells and losing a considerable part of its manurial value.
The filter-press cake, on the other hand, can be dried, without difficulty, without fermenting, and, once thoxoughly dried, it can be ground and will then keep for any length of time. It thus forms an excellent food for stock. When the practice of using scum-cake meal, as this may be termed, is in- troduced for the first time, it is well to mix it with other food, gradually increasing the quantity of the scum-cake from day to day. It may be given mixed with chaff and molasses, or mixed with mo- lasses and given in the same manner as oil-meal. Cattle fed upon this, together with their ordinary diet of cane-tops or grass, fatten and keep in ex- cellent condition and work well. No ill effects will follow from its use if care be taken to reject in the drying process any that is not perfectly sweet and good. By following this plan the quantity of oil- meal purchased on a sugar estate may be reduced, and in this way the filter-press effects another im- portant saving.
In order to dry the cake, the author advises that, every time the press is opened, the softer portions of the cake, which will be found in the pipes, etc., of the press, be fed to the stock as soon as possible, thus getting rid of this, which it would be difficult to dry, and providing a considerable portion of the daily food. The firm cake should then be exposed to the sun, if the weather be dry, and the cakes
96 MANUAL FOR SUGAR GROWERS.
turned from time to time. At night, or in damp weather, the cake is broken into small pieces, say one- to two-inch cubes, and placed on shelves made of galvanised iron-wire netting of one-inch mesh. These shelves should be placed one above the other, about eighteen inches apart, and may extend from near the floor to the roof of the room they occupy. A free current of air should be maintained through the room, and rain be carefully excluded. When thoroughly dry the cake should be ground in a mill to a fine meal, and then may be stored in casks. It is advisable to spread the meal in a thin layer on a dry floor, and turn it occasionally, to dry it thoroughly, before packing it in casks. Thorough drying is of the utmost importance. It is well to have two hand-mills, one to break the cake into small cubes, and the other to grind the dry cake to meal.
The cake from the press is valuable as manure, and, after it has been eaten by the stock, a large proportion of the constituents of manurial value will be recovered, if the cattle-pens and stables are well arranged.
From the analyses it will be seen that as dried scum-cake contains about twelve to fourteen per cent. of phosphate of lime, and superphosphate contains thirty to thirty-three per cent., five hundredweight of scum-cake will be required to take the place of two hundredweight of superphosphate, and this will contribute about eleven pounds of nitrogen, equal to thirteen and one-half pounds of ammonia, or about half a hundredweight of sulphate of am-
MANUAL FOR SUGAR GROWERS. 97
monia; and thus five hundredweight will be worth about twenty shillings, or fully four pounds per ton, if used direct as manure.
What scum-cake is produced in excess of what the stock can eat should be ploughed into the soil at the rate of about five hundredweight per acre, or sold if a profitable market can be found.
The quantity produced will be roughly half a hundredweight per hogshead of sugar made. It will thus be seen that no estate can afford to be without a filter-press, and it is somewhat surprising to notice how slowly proprietors have placed them in their boiling-houses.
Of the nature of the colouring matter of cane- juice very little is known; it becomes darker when the solution is alkaline, and also when submitted to the oxidising action of the air; hence, when it is desired to obtain sugar of fine colour, it is neces- sary to render the juice slightly acid ; and for this reason only those chemical agents which bleach by reduction are of any value in bleaching sugar solu- tions.
7
CHAPTER VIL.
Manufacture of Sugar.—Inversion.—Open-fire Process. —Steam Pans.—Muscovado Sugar.—Vacuum Pan.— Method of Operat- ing.—Triple Effect. —Centrifugals.—Production of High-class Sugars.—Use of Sulphur.— Carbonation.— Phosphoric-acid Process. —Animal Charcoal.
HATEVER kind of sugar is to be made, the process of manufacture is practically that de- scribed in the preceding chapter, up to this point. From this point the processes differ according to the apparatus employed in evaporating the juice, and the kind of sugar produced. In general terms the process consists in evaporating the juice to a thick syrup and allowing the sugar to crystallise out.
A word upon the chemistry of sugar is necessary here. Cane sugar has the composition represented by the formula C,,H,,O,,, and if this be heated for a long time with water, H,O, it is decomposed and forms another kind of sugar,—glucose or invert sugar, this change being represented by the equa- tion :
OcHOm: Ei. HiOs p= 0; Cee
Cane Sugar and Water yield Glucose.
If any acid be present, this change takes place with very great rapidity, and this is one of the rea- sons for neutralising the acid of the cane-juice in
MANUAL FOR SUGAR GROWERS. 99
the operation of tempering. Various acids act with different degrees of rapidity. The mineral acids, as a rule, effect the change in a very brief space of time. The organic acids act much more slowly. This change of cane sugar to glucose is known as inversion, from the fact that cane sugar, when ex- amined by polarized light, rotates the plane of po- larization to the right, while invert sugar rotates it to the left. The art of the sugar-manufacturer consists in extracting the sugar from the juice with as little inversion as possible, for to inversion is due the production of molasses, with its consequent loss of sugar and loss of money, molasses being of small value. The chief agents causing inversion are acids, heat, and certain ferments to be referred to later.
The simplest method of manufacture consists in boiling down the clarified juice to a thick syrup in iron pans over a fire, and pouring out the syrup into shallow trays to crystallise. These iron pans are nearly hemispherical and are arranged in a series— usually of four or five—diminishing in size from the large one, into which the juice from the clarifier flows, to the small one in which the final concentra- tion is completed. These pans are placed over a continuous flue, the fire being under the small pan, the object of this arrangement being to diminish as much as possible the time of final concentration ; for as the syrup becomes dense it boils at a very high temperature, and therefore inversion proceeds with ereat rapidity.
This in effect is the common method of manufac-
100 MANUAL FOR SUGAR GROWERS.
turing muscovado sugar on estates not provided with steam machinery. Its chief defect lies in the fact that as the evaporation of the syrup is finished over the open fire there is considerable inversion: at the same time the process is difficult to control, hence the resulting syrup contains much glucose and is subject to great variation in density.
On estates possessing steam plant this process is modified by evaporating the syrup to a moderate de- gree over open fires, and finishing the evaporation in steam-heated pans. By employing this method the inversion is very much less than in the one just de- scribed, though even here the inversion is very rapid and has led to the abandonment of this method of working in those places where sufficient juice is dealt with to justify a large outlay for machinery.
To complete the description of the muscovado process: the syrup is boiled until the workman in charge of the pan judges by the manner in which the liquid boils that it is sufficiently concentrated, it is then run out in thin layers in coolers to crys- tallise. It is better to use a thermometer to ascer- tain the correct point at which to “strike” or dis- charge the contents of the pan. It is found that good results follow from striking when the temper- ature of the boiling mass reaches 238° to 240° F. ; in this way much more regularity in the character of successive strikes is secured.
The coolers into which the concentrated syrup is run are usually about 10 x6 feet and 2 feet deep; a number of these are employed, and the syrup is run into them in thin layers ata time. After being run
MANUAL FOR SUGAR GROWERS. 101
into the coolers the syrup is gently stirred at inter- vals to promote crystallisation. When the coolers are full, the crystallised mass is dug out and packed in hogsheads, boxes, bags, etc., in order that the fluid uncrystallised portion—the molasses—may drain out. This is aided by boring holes in the wooden packages to permit of the escape of the molasses. The polariscopic test of the sugar depends entirely on the extent to which the draining extends. The object of the sugar-maker, of course, should be to obtain a sugar testing as high as possible, and at the same time yielding the minimum quantity of mo- lasses. Sugar in the manufacture of which much inversion may have taken place may yet test high by efficient draining, but at the same time an ex- cessive quantity of molasses will be produced.
Muscovado sugar, by thorough draining, may be obtained testing as high as 94° by the polariscope. Good ordinary muscovado should test from 88° to 91°. Careful attention to the tempering and the correct “ striking-point”’ are important factors in se- curing a high test. Care should also be taken that a sufficient number of free outlets are provided in the packages in which the sugar is cured: it is a good practice to burn the holes in the hogsheads, to pre- vent the fibres of the wood swelling up and closing the hole.
From a large number of analyses the author finds, on estates fairly conducted, that to make a hogshead of sugar of 2,000 pounds net and its accompanying molasses, —say about 30 gallons,—requires 2,600 pounds of cane-sugar in the juice. This on estates
102 MANUAL FOR SUGAR GROWERS.
having steam pans but not filter-presses ; where filter- presses are used the quantity will be about 2,525. The packages in which the sugar is placed to drain are arranged in a curing-house, the floor of which is furnished with beams or stanchions on which the packages stand, the molasses draining down onto a floor beneath, where gutters conduct it to molasses tanks, whence it is filled into puncheons for sale. The packages in which the sugar is cured are usually closed up and shipped without any further treat- ment; sometimes it is the custom to remove the sugar from the hogsheads or boxes and repack it in bags. This is the outline of the process followed in mak- ing muscovado sugar for refiners’ use. It will be seen that the process is simple, requiring neither elaborate machinery nor highly skilled labour ; at the same time it is very wasteful. The rate of inversion may be judged from the following analyses: The samples in Series A were obtaimed from an estate provided with a windmill, the concentration of the juice being finished over the fire. The samples in Series B were from an estate having steam plant, the syrup being concentrated to a certain density over the fire, and the evaporation finished in a steam pan.
Glucose per Total sugar.|Cane sugar.| Glucose. 100 cane sugar. A. Syrup, 1st copper.........- 21.48 21.09 0.396 1.87 Syrup, 3d copper .......... 39.88 38.94 0.942 2.44 Syrup, as struck.........-- 83.57 71.12 12.45 17.54 B. Sugar as supplied to pan.. 66 94 62.10 4.85 7.24
Sugar as struck from pan.. 83.81 75.12 8.69 10.36
MANUAL FOR SUGAR GROWERS. 103
The last column gives the quantity of glucose in the syrup for every one hundred parts of cane sugar, or what is known as the glucose ratio.
In the case of the vacuum pan, about to be de- scribed, the inversion is but very slight. These re- sults are expressed graphically in the diagram, curves representing the work of the vacuum pan and the concretor being added for comparison.
Glucose in
0 1 20° «80e 40 BO 60-70 60 - 90" 100 Total sugar in syrup.
Fig. 15.—Curves illustrating the increase of glucose with increasing concen- tration in various processes of sugar-manufacture.
It is necessary here to say a few words on the theory of boiling. It is well known that the tem- perature at which a liquid boils depends entirely on the pressure to which it is subjected. The pressure to which liquids in open vessels are sub- jected is the pressure of the atmosphere, and this under ordinary conditions is a pressure of nearly
104 MANUAL FOR SUGAR GROWERS.
fifteen pounds per square inch. This is measured . by means of the barometer, in which the mercury usually stands at a height of about thirty inches. From this it follows that a liquid boils at a higher temperature when the barometer rises, and at a lower temperature when it falls.
If, by means of an air-pump, the vapour be re- moved from above a liquid boiling in a closed ves- sel, the temperature of the boiling-point will be reduced, according to a well-known law. In the case of water, the following table gives the boiling- point under various pressures :
Temp., F iineies |e Fb epee A eo ke acacioiee 0 ISO oc Kelas KR Sate 254 a || Line es ape Sheer ales eh 64 DS tt .2 aes nee oe 26 PQ rene Mee Soe ae 10 OAD econ clan oe ore aera 264 (bs!) Sgt ne ere el aa Sey 15 ec eae hoe eee 27 PGW fois atest eee 20 x | ay ie Ii Dye a 274 Te oes ede eee 224 SU ( Ses | Seeing MOB arte! 2 5 6 Se Pe ae oe hy EO 24
Now, from the figures given in connection with the manufacture of muscovado sugar, it will be seen that it is the increased heat, as the syrup becomes concentrated, which leads to such rapid inversion and consequent loss. Hence, by boiling the syrup under reduced pressure we have the means of pre- venting this loss. This, in practice, is carried out by means of the vacuum pan (Fig. 16), which consists of a closed vessel, A, in which the syrup is boiled, the heat being supplied by a series of steam coils, B, at different heights. The steam, as fast as it is formed, is drawn off through the pipe, C, by means of the
MANUAL FOR SUGAR GROWERS. 105
air-pump, D, worked by a steam-engine. The steam is condensed as quickly as possible by being
STEAM PIPE
Fie. 16.—Diagram of vacuum pan.
brought into contact with cold water in C and HE, the condenser. From the table of pressures and boiling-points on page 137, it will be seen that the more effectually the air-pump and condenser pro- duce a vacuum in A, the lower will be the boiling- point of the syrup.
In practice, the pressure in the interior of the pan A is about one to two pounds less per square inch, instead of fifteen pounds as in open vessels, and the syrup boils at a temperature of 110° to 120° F. An additional advantage of this low temperature is that it allows the syrup to crystallise, or “ grain,” even during the process of boiling, so that the syrup, as discharged. from the pan at the end of the opera- tion of concentrating-——masse cuite, as it is called— is a mass of crystals. On allowing this to stand for a few hours, further crystallisation takes place, and the mass is then ready to be cured.
106 MANUAL FOR SUGAR GROWERS.
A certain amount of skill is required to adjust the conditions during the concentration, that the crystals may be properly formed, and in this the art of the pan-boiler consists.
The following is an outline of the method of work- ing: The air-pump is first started so as to create a vacuum in the pan; the cock connected with the syrup or feed-pipe is next opened, and syrup drawn into the pan in sufficient quantity to cover the lower steam coils ; steam is turned on, and the syrup rapidly boils down. Fresh syrup is drawn in, in small quantities, from time to time, until the boiling mass begins to show signs of crystallising or grain- ing. When this takes place the successive charges of syrup are admitted with care, so as to build up the grain slowly. Larger quantities of syrup being admitted at a time, as the pan becomes filled, and steam being turned on in the successive coils as the syrup covers them, the progress of the operation can be watched through sight-glasses let into the upper part of the pan. Small quantities of syrup can be withdrawn for inspection by means of an ap- paratus known as a proof-stick, an ingenious piece of apparatus fitted to every vacuum pan.
Attached to the pan are thermometers, by means of which the temperature of the contents of the pan can be ascertained. Vacuum gauges are also at- tached, which show the extent to which the pan is exhausted of air and vapour. The vacuum gauge indicates “inches of vacuum,” or the height in inches to which a column of mercury would rise in a tube one end of which was connected with the
MANUAL FOR SUGAR GROWERS. 107
pan while the other dipped into mercury. If the vacuum were perfect, the mercury would rise to the same height as in the barometer, — about thirty inches. During the ordinary working of the pan the vacuum is about twenty-six to twenty-eight inches.
If the formation of grain be allowed to take place when only a small quantity of syrup is in the pan, this is known as “ graining low down.” It is often the custom not to allow grain to form until a con- siderable quantity of concentrated syrup is in the pan, and this method of working is known as “ grain- ing high up.” By graining high there is some sav- ing in time; but as a rule, particularly with small pans, the grain is not so large or so regular as when the syrup is grained low down. To obtain large and uniform crystals it is necessary to allow the grain to form slowly, admitting thin syrup in small quanti- ties, and allow the boiling to take place slowly and steadily.
It sometimes happens from bad manipulation that the whole of the mass becomes cloudy from the formation of minute crystals. This condition of things, known as false grain, is to be guarded against most carefully, as it leads to considerable loss; the masse cuite under these conditions will not part with its molasses, and a sticky unsaleable pro- duct results. If the appearaiice of false grain be detected at once, the difficulty may be overcome and the false grain destroyed by admitting a consid- erable quantity of thin syrup into the pan and rais- ing the temperature of the boiling syrup by wholly or partially destroying the vacuum for a short period.
108 MANUAL FOR SUGAR GROWERS.
This causes the minute crystals constituting the false grain to dissolve.
It is customary to discharge only a portion of the masse cuite from the pan and to take fresh syrup upon the remainder ; this is known as doubling. By working in this manner the size of the grain is in- creased and some time is saved. Care is required in conducting the operation of doubling. Some syrup will get sticky after the operation is performed once, while in the case of other syrups it may be performed three or four times in succession. In doubling it is necessary to take in the fresh syrup to open up the masse cuite in the pan with the greatest care ; if the syrup be admitted too rapidly false grain will result.
If a glance be given to the diagram of the vacuum pan it will be seen that the pipe C, conveying away the steam from the pan, must be heated to a certain extent, and the idea occurred to engineers that this heat might be utilised; the result was the invention of multiple-effect evaporation, a system in which a liquid is concentrated in a series of closed vessels, the steam from one vessel serving to heat the liquid in the next. It is evident that the pressure in the successive vessels must be gradually diminished, in order that the steam—having the temperature of the boiling liquid—from one vessel may be of a higher temperature than the’ boiling-point of the liquid in the next. The following diagram of a triple effect will enable the reader to follow the description of the method of working.
Juice or thin syrup is run into Vessel 1, and this is heated by means of a steam-drum supplied with
MANUAL FOR SUGAR GROWERS. 109
steam from some suitable source; the vapour or steam generated from the boiling juice passes by
STEAM FROM JUICE IN VESSEL2
Fie. 17.—Diagram of triple-effect apparatus.
means of the conducting-pipe into the steam-drum of Vessel 2, and the steam from Vessel 2 passes into the steam-drum of Vessel 3. Now, in Vessel 1 the vacuum is but very slight, so that the boiling-point of the liquid, and consequently the steam produced, have a temperature of about 180° F., corresponding to a vacuum of about five inches; in Vessel 2 a vacuum of about fifteen inches is maintained, and in consequence the boiling-point in this vessel is about 150° F., so that there is a difference of 30° between the temperature of the steam and the boil- ing-point of the liquid, a sufficient difference to cause the liquid in Vessel 2 to boil, and thus supply steam at 150° F. to the steam-drum of Vessel 3, in which the vacuum is maintained at about twenty- seven inches and the liquid boils at 120° F. Thus the liquid in Vessel 3 is boiled by the steam from Vessel 2, which has a temperature 30° above the boiling-point of the liquid in Vessel 3. Suitable
110 MANUAL FOR SUGAR GROWERS.
air-pumps are attached to the apparatus, and pumps to remove the condensed water from the steam- drums, which, being under a pressure below that of the atmosphere, require to be pumped out, except 1 in the case of the steam-drum in Vessel 1.
The syrup flows in a slow, continuous stream through the whole apparatus, and on the correct adjustment of the rate of flow depends the success- ful working of a multiple - effect apparatus. The syrup is concentrated in the triple effect to a suffi- cient density to be taken into the vacuum-pan, in which it is boiled to grain as above described.
The principle is the same whether the series con- sists of two, three, four, or more vessels. Various improvements in the details of the parts of the apparatus have been devised from time to time, in order to increase the efficiency or to render the working simpler.
In some of the most improved evaporators of this type the economy of working is very great, nearly forty pounds of water being evaporated for each pound of coal burned. It will be remembered that one pound of coal will convert only fourteen pounds of boiling-hot water into steam when the evaporation is accomplished in ordinary open vessels ; indeed, this is the theoretical quantity, and in practice the quantity evaporated is very much less than this, usually not more than eight or nine pounds.
The latest evaporators aim at allowing the fluid to be evaporated to enter Vessel 1, and, after flowing over the steam-heated surface, to pass into Vessel 2, and over the heating surface of this into Vessel 3 ;
MANUAL FOR SUGAR GROWERS. Lh
the evaporators thus contain but a small quantity of liquid at one time, but this passes through with con- siderable rapidity, a point of great importance in sugar-manutacture. The above statements briefly indicate the importance of the multiple system of evaporation ; and this system must in time replace the processes In use in the West Indies, if these isl- ands are to compete successfully with other sugar- erowing countries.
Curing Sugar.—tn the case of muscovado sugar it has already been said that the only treatment to which the sugar is subjected to fit it for the market is to permit the uncrystallised syrup—molasses—to drain away through holes in the packages, a process which is very tedious and seldom complete. Where the crystals of sugar are of fair size, as in the case of vacuum-pan sugars or large-grained muscovado, the molasses is usually removed by the aid of a cen- trifugal drier.
It is well known that if any body be made to re- volve rapidly there is a tendency for all the parts to fly outward from the centre; this may easily be shown by twirling the handle of an umbrella be- tween the hands, when the ribs will fly out. The same thing is seen in the governor of the steam en- gine, where the two heavy balls fly out from the centre as soon as they begin to revolve, and fly farther out the greater the speed at which they are driven.
The apparatus in which this principle is applied to the draining of molasses from sugar crystals con- sists of a shallow, circular drum or basket, closed at
112 MANUAL FOR SUGAR GROWERS.
the bottom and open at the top, the sides being perforated and constructed of various materials, either perforated copper or wire gauze, or some sim- ilar substance. This basket is capable of being re- volved horizontally at a very rapid rate. The sugar, or masse cuite,is thrown into the basket, which is then made to revolve. The sugar soon flies from the centre and spreads itself upon the sides of the basket. Here its progress is arrested, but the mo- lasses escapes through the perforations in the walls. The basket revolves in an iron casing which serves to collect the molasses, and from this the molasses is run into suitable tanks. After a few minutes’ treatment in the centrifugal machine the sugar is freed from its molasses. If a fine-coloured sugar is required, it is the practice to wash the crystals dur- ing their revolution with a small quantity of water or bright syrup. In order to obtain a large yield of sugar it is advisable to allow the masse cuite to be- come cold before centrifugalling, as a considerable quantity of sugar crystallises out from the syrup during the process of cooling. Brighter coloured sugars can be obtained, though in somewhat smaller quantity, by centrifugalling the masse cuite warm. The syrup or molasses thus drained from the crystals is usually boiled again in order to recover another lot of crystals. That this may be done suc- cessfully it is advisable that the syrup be used as quickly as possible, as any fermentation is very detrimental to the yield of sugar ; if it can be worked up as it leaves the centrifugals, so much the better. The syrup is mixed with sufficient hot water to re-
MANUAL FOR SUGAR GROWERS. 1138
duce the density to about 20° B., and lime added, phenol-phthalein being used as an indicator; the mixture is heated in a steam-heated vessel or ‘‘ blow- up,” carefully skimmed, to remove impurities, and boiled to grain in the vacuum pan, yielding second crystals. It is often the practice to submit the syrup obtained by this operation to similar treat- ment, thus obtaining a small quantity of third sugar.
It is possible to obtain upwards of ninety-two to ninety-three per cent. of the total cane sugar in the juice in the form of crystallised sugar, and upwards of seventy-four per cent. should be in the form of first crystals. With good working the quantity of molasses should not exceed fifteen to twenty gallons per ton of sugar made.
Various processes are employed to produce sugar of fine colour direct from cane-juice. The one most commonly employed consists in decolourising the syrup by means of sulphurous acid. When sulphur is burned, pungent fumes of sulphur dioxide are given off, which dissolve in water, forming sulphur- ous acid. This substance has powerful bleaching action on most vegetable colouring matters and in the act of bleaching is itself converted into sul- phuric acid. To apply this in the sugar industry sulphur is burned in a small furnace, and the fumes, urged forward by means of a steam jet, are brought into contact with the cane-juice, by which they are dissolved and which they decolourise. There is some difference of opinion as to the best time in the treatment of the juice at which to apply the sul-
phurous acid. Some apply it as the juice runs 8
114 MANUAL FOR SUGAR GROWERS.
from the mill, before tempering, while others apply it after tempering ; the author believes that it is used to best advantage as late in the process of concen- tration as possible, say after subsiding or just be- fore the syrup is taken into the vacuum-pan. Ii used early in the process there is danger of inver- sion from the presence of the sulphuric acid gen- erated, while if used before tempering a good deal of the bleaching action is lost, as the solution must be slightly acid to obtain a fine colour, and efficient clarification cannot be obtained with acid juice.
In making high-class sugars it is usual to “sub- side,” z.e., to allow the syrup, boiled to a density of about 20° B., to stand for twelve hours, in order that the impurities may settle to the bottom. Bright juice, free from floating impurities, is thus obtained. No fermentation or inversion takes place if the pro- cess is properly conducted.
Decolourisation of the juice is often effected by forming a precipitate of some solid substance in the juice. The carbonation and phosphoric-acid pro- cesses may be taken as types of processes of this class; their success depends on the fact that precip- itates tend to remove many kinds of vegetable col- ouring matter from solution.
In the carbonation process a quantity of lime far in excess of that required to neutralise the juice is added. This dissolves in the form of mono-sac- charate of lime. Carbonic-acid gas is afterwards forced into the solution, which decomposes the sac- charate, with the formation of cane sugar and car- bonate of lime ; the latter, being an insoluble sub-
MANUAL FOR SUGAR GROWERS. 115
stance, falls to the bottom of the vessel, carrying with it a considerable amount of impurities and col- ouring matter. The carbonic acid required for this process is usually obtained from the kiln in which the lime for the use of the factory is burned.
In the phosphoric - acid process, lime is added to the juice in somewhat larger quantities than is re- quired to effect clarification in the ordinary way. Af- ter the removal of the scum, phosphoric acid is added to the juice, when an insoluble phosphate of lime is produced, which is best removed by sub- siding ; this precipitate carries down with it colour- ing matter and other impurities. Various forms of phosphoric acid are on the market, so prepared as to render them easy of carriage. The process is one requiring no special appliances, and is easily carried out.
The use of animal charcoal is but rarely resorted to in the colonies. For the removal of the colouring matter from the juice no other agent so completely decolourises sugar solutions. The difficulties attend- ing its use are such as can only be successfully coped with when the manufacture is conducted on a very large scale. Its use is almost entirely confined to the process of refinmg. The charcoal is placed in iron cylinders 5 or 6 feet wide and 20 or more feet high. The juice after clarification is allowed to flow in at the top of the column, and after percolating slowly through the charcoal it flows out at the bottom in a colourless state. After having been in use for some time the charcoal loses its decolourising properties ;
116 MANUAL FOR SUGAR GROWERS.
it is then reburned and after washing is again fit for use.
It is worth while remembering that only those bleaching agents that bleach by reduction are of - value in the sugar industries. Oxidizing agents, which are frequently used as bleaching agents in other industries, do not bleach, but darken cane- juice and its products.
CHAPTER VIII.
Hydrometers or Saccharometers, and their Use.
HE sugar in cane-juice being subject to very ereat variation, it is convenient to have some means of ascertaining approximately the richness of the juice. This is usually done by means of the hy- drometer, the use of which depends on the following points: When a solid substance, such as sugar, is dissolved in water, the density or specific gravity * of the solution is found to be greater than that of water, and increases in proportion to the quantity of solid substance dissolved ; hence, if the fluid con- tain only one substance in solution, it is easy to ascertain precisely the amount dissolved by merely finding the specific gravity ; but when the fluid con- tains two or more substances, this becomes quite impossible, as both have a similar effect in increas- ing the specific gravity, and it is impossible to say how much of the increase is due to one substance
and how much to a second. When any body floats in a fluid it sinks until the part submerged displaces exactly the same weight * Density or specific gravity is the weight of any substance
compared with the weight of an equal volume of water taken as unity.
118 MANUAL FOR SUGAR GROWERS.
of fluid as the body itself weighs ; thus any floating body will be more or less submerged as the fluid in which it floats is less or more dense. ‘This princi- ple is applied to the construction of hydrometers, which serve to measure the density of fluids by the depth to which they are submerged when they are floated in the fluid. Hydrometers are usually made of the form shown in the figure, and may be of glass or metal; a scale marked on the stem measures the amount submerged, and thus the density of the fluid. Hydrometers are made with scales of various values, according to the uses for which they are to be em- ployed.
The hydrometer commonly used on sugar estates is graduated with the scale known as Beaume’s. In the table on pages 139 and 140 is given Fia. 18.—Beaumé’s the quantity of sugar in solution cor-
uiccceet eda responding to the various degrees
Beaume.
For use in the West Indies it is most convenient to have the hydrometer graduated to indicate from 6° to 12° B., this range covering the. variations of ordinary cane-juice, and on an instrument thus eraduated the marks are sufticiently wide apart to admit of their being read with considerable accu- racy. The use of instruments having a scale rang- ing from 0° to 50° or 60° B. cannot fail to be mis-
MANUAL FOR SUGAR GROWERS. LS
leading. The instrument should be graduated at a temperature of 84° F’.; sometimes instruments are found graduated at 60° F., the temperature em- - ployed when they are to be used in a cold climate ; the readings of such instruments may be corrected by noting the temperature of the liquid tested and adding .0265 for every degree F’. above the temper- ature at which the instrument is graduated, or one- tenth for every four degrees difference of tempera- ture.
Another hydrometer, known as Balling’s or Brix’s, is commonly employed in the sugar industry. The readings of this scale indicate the percentage of sugar present in solution; thus 14° Balling indicates a solution containing fourteen per cent. of sugar.
From what has been said it follows that, when ap- plied to cane-juice, the quantity of sugar can only be estimated approximately by the hydrometer, which is unable to distinguish between cane sugar, elucose, or other dissolved substances.
In ascertaining the density of cane-juice, it is the common practice to take the juice as it comes from the mill, and to put the hydrometer into this; this method involves several sources of error. Owing to the presence of air, the fluid appears to be lighter than it really is, and by taking a series of observa- tions on the same sample in rapid succession, a number of increasing densities will be obtained ; at this stage, too, the juice contains in solution a quan- tity of organic matter other than sugar, which is shortly to be removed in the process of clarification.
120 MANUAL FOR SUGAR GROWERS.
When the instrument is used as a saccharometer it is preferable, then, to take the density after clari- fication, when the air and a considerable quantity of impurities have been removed. To do this, a sample should be taken from the clarifier and rapidly cooled by pouring into a shallow metal dish floating in water ; when cooled, the juice is poured into a deep narrow vessel, and the density taken; the tempera- ture of the liquid being noted, and a correction made if the temperature differ from that at which the hydrometer is graduated. Much more trust- worthy results are obtained by this method, as the density is taken in juice containing much less im- purities and free from air.
The following method of using the hydrometer may be found useful in muscovado boiling-houses, where chemical control is rarely obtainable ; in larger factories more accurate methods are usually em- ployed. By taking the density in the manner di- rected, and calculating the amount of sugar present in the juice from the table, the planter can ascertain approximately how the work of the boiling-house is being carried on ; for, by dividing the total pounds of sugar by 1.3, he will obtain the number of pounds of cured muscovado sugar which should be made. This, of course, will only be approximately true, but, being so easily carried out, serves as a useful control. It is advisable to make a deduction of seven or ten per cent. from the total sugar in the case of young canes, or of three per cent. in the case of sound ripe canes, on account of the glucose, etc., present.
MANUAL FOR SUGAR GROWERS. 121
The following example will explain the method :
Pounds per
gallon. 5,000 galls. juice at 10° B., corrected, = 1.9896 = 9,698 4,000 galls. juice at 11° B., corrected, = 2.1513 = 8,605
Pounds.
Dos eee ocean ees S 18,303 Hiessae Per CONLY.c ai< rer ia be see's se o epee 549 Pounds sugarestimated « . ces sscce omc 17,754 Mivided! Dyed. 256 s.aiias eo ape dee crete ees 13,657
The 9,000 gallons of juice should therefore pro- duce 13,675 pounds of muscovado sugar, or 6.8 hogsheads of 2,000 pounds net ; or 1 hogshead from 1,176 gallons of juice.
It will be found instructive to test each week’s working on the above lines. Careless working or waste will be thus detected.
CHAPTER IX.
Molasses.—Production, Composition, and Uses.—Recovery of Sugar from Molasses,
OLASSES will vary very greatly in character ° according to the manner in which the sugar from which it drains has been produced. That pro- duced in the manufacture of muscovado sugar with- out steam pans will frequently be dark in colour from slight charring. When steam pans are used the colour is usually improved, the composition re- maining about the same. When the vacuum pan is employed, the cane sugar is usually more perfectly extracted, so that vacuum-pan molasses contains much more glucose and impurities than molasses obtained in the muscovado process. The following analyses may be taken as represent- ing the various qualities of molasses:
Muscovado Vacuum-pan
molasses. molasses. Cand Saar y Ju eee tune sec nae aeiek 40 to 50 30 to 40 HHCOSE 2s. cada pee aint eee ae 15 to 25 20 to 35 Mineral nratter’ 37. os.s 3202 \s cen acces 2to 6 5to 8 Organic matter other than sugar....... 3 to 10 10 to 20 Water. 2:2. atedencme eee eens 20 to 30 20 to 30
The quantity of molasses made per hogshead or per ton of sugar also varies greatly, and depends
@
MANUAL FOR SUGAR GROWERS. 123
both on the quality of the juice and on the skill of the sugar-manufacturer.
The production of molasses or uncrystallizable syrup is due to the fact that glucose, mineral mat- ters, and organic impurities other than sugar, prevent the crystallisation of cane sugar. Hence the quan- tity of molasses will be greater in proportion to the quantity of these substances present in the juice. But by far the most important agent is the glucose formed by inversion during the process of boiling ; so that it is at once seen that, not only does the for- mation of glucose mean the loss of so much cane sugar by inversion, but also the further loss of another portion by preventing its crystallismg. In careful working with vacuum pans it is found that one part of glucose prevents the crystallisation of an equal weight of cane sugar. In the molasses of the muscovado process the proportion of cane sugar to glucose is much greater than this.
The quantity of molasses produced in the musco- vado process is largely dependent on the manner in which the process is conducted. It varies from 30 to 50 gallons, or more, per hogshead of 2,000 pounds. There are two points by attention to which the quantity of molasses can be kept low,— care in tempering, and brisk boiling in the steam- pan ; long-continued boiling of concentrated syrup is one of the greatest producers of molasses.
In the vacuum-pan process the yield of molasses depends chiefly on the amount of impurities in the juice, inversion during manufacture in this case
being but slight. Where only first and second
124 | MANUAL FOR SUGAR GROWERS.
sugars are made, the quantity of molasses will vary from 10 to 20 gallons per 1,000 pounds sugar pro- duced. But where third sugar is made from the molasses, the quantity may be reduced to from 5 or 10 gallons per 1,000 pounds of sugar produced.
After the molasses has been made, considerable loss is often experienced from fermentation. The packages overflow, and often arrive at their desti- nation nearly half empty. It is believed that this could be remedied by heating the molasses to about 200° to 212° F., in order to destroy the germs to which fermentation is due; a clarifier or steam pan would afford a means of doing this.
The question arises, What is to be done with the molasses? In the case of muscovado molasses of good colour and flavour, there is a ready outlet as a food material, and this doubtless has enabled the wasteful muscovado process to hold its own in the West Indian islands for so long, the value of the molasses with a steady demand, together with the small cost of the machinery and appliances, ren- dering it suitable to the small-estate system so gen- eral in these islands.
With molasses of inferior quality, and vacuum- pan molasses, from which so large a proportion of sugar had been extracted, leaving a high percentage of impurities, the case is different. Molasses of this kind may serve as food for cattle, pigs, ete. But its value is so small as to scarcely counterbalance the cost of packages, freight, and other expenses. No doubt the right use to which to apply it is to con- vert it into alcohol, though the excise regulations of
MANUAL FOR SUGAR GROWERS. 125
some colonies impose difficulties which render the use of small stills on small estates unremunerative. One or more large distilleries in each colony would probably be able to overcome these difficulties.
Many processes have been suggested, from time to time, for dealing with molasses. These, however, apply almost exclusively to the molasses of beet sugar, and it will be seen that it will not pay to ap- ply any of these processes to the molasses obtained from the sugar-cane. These processes have for their object the recovery of sugar, or the recovery of potash, or both. Several processes for the recov- ery of cane sugar depend on the fact that this sub- stance will combine with lime, strontia, etc., to form a compound insoluble in water, while glucose will not. The glucose is separated by washing the pre- cipitate or sediment with water, and the cane sugar recovered by treating the insoluble compound with carbonic-acid gas, which converts it into carbonate of lime or strontia, insoluble in water, and sugar which dissolves. Now, beet molasses contains far more cane sugar than molasses from the sugar-cane, and but little glucose. An average sample of beet- molasses will contain :
eR. SAAT sos oo tral since soln eines miners, ele rein es 50 MICO E. okt sek sw cce besos Sas eis an ee wees o's 1.5 ENCE AE MAAGLOR c.g Saas 2 spice Sos ales 12 Organic matter other than sugar f......... 16.5 DN alec a 2) wa ce na 2 ai mys Sins wom -w, os ohne 20 GANG ie oa ian ois ac aint wee ee oa ees 100
* Contains potash = 5 per cent. + Contains nitrogen = 1.5 per cent.
126 MANUAL FOR SUGAR GROWERS.
The value of the sugar recovered will be insufti- cient to make processes of this character remunera- tive in the case of sugar-cane products.
Beet molasses contains a very large quantity of potash,—on an average four or five per cent. On mixing molasses of this character with sulphate of alumina, a considerable quantity of alum, which is a double sulphate of potash and alumina, crystal- lises out. Processes of this kind have been worked successfully, but are quite inapplicable to cane mo- lasses, as the quantity of potash present is usually only about one-half per cent.
The problem of finding a remunerative outlet for vacuum-pan molasses is undoubtedly one of the most difficult ones which owners of large factories have to solve, and for them the distillery appears to offer the easiest solution.
CHAPTER X.
Fermentation.—Nature of Ferments.—Conversion of Cane Sugar into Alcohol.—Setting up Wash.—Yield of Alcohol, —Dis- tillation.—Forms of Stills.
HEN cane-juice is allowed to stand for some hours various changes take place. The sugar disappears and a certain quantity of alcohol is found in its place. This change is known as fer- mentation. This term, however, is not limited to the conversion of sugar into alcohol, but is ex- tended to other changes of the most various kinds, e.g., the conversion of alcohol into acetic acid, etc.
It is now a matter of common knowledge that all these changes—which we term fermentation, putre- faction, and decay—are due to the life and growth, in the changed substance, of various minute organ- isms, and that if steps be taken to kill those present in a given substance, and to prevent the access of others, even the most easily putrescible substances, such as meat, fish, soup, milk, fruit, and the like, may be kept without change indefinitely. We have commercial examples on an enormous scale of the truth of this, in the various canned foods of all de- scriptions now so abundantly used. These are, for
the most part, prepared by closing the food-sub-
128 MANUAL FOR SUGAR GROWERS.
stance in the tin, leaving a small hole in the lid for the escape of air. The tin and its contents are now heated to the temperature of boiling water in order to kill the putrefactive germs which are present,— not merely to remove the air, as is sometimes supposed,—and while hot the small hole is closed by means of a drop of solder. Cane-juice treated in the same manner would remain unchanged for any length of time. Air free from germs will not cause any fermentative or putrefactive change.
If a drop of liquid in which sugar is undergoing change from sugar to alcohol be examined under a microscope, a great number of little bladder-like bodies will be seen floating about in it, the appearance when high- ly magnified being as in the figure. These are the germs of alcoholic fermentation, or the yeast-plants, as they are ED more ome called. Each little plant con-
Se sists of a single cell, and mul- tiplies by budding. A pro- jection forms on one side of the parent cell, and this gradually grows until it becomes a perfect cell like the parent. This is known as reproduction by gem- mation or budding. The yeast-plant also multiplies by forming spores in its interior. The contents col- lect into masses which, on the rupture of the sur- rounding cell-wall, are set free and develop into new yeast-cells. This method of multiplying is less common than the former.
MANUAL FOR SUGAR GROWERS. 129
These cells are very minute, measuring on an average about zo/5q Of an inch in diameter, so that the enormous number of 64,000,000,000 could go into the space of one cubic inch.
The change of sugar into alcohol is due to the life and growth of this particular organism. The sugar may be regarded as its food, and the alcohol as its waste product. Now, there are a great variety of these ferments, each of which produces certain definite changes. Thus we have the alcoholic fer- ment; the acetic ferment, which converts alcohol into acetic acid; the viscous ferment, which converts cane-juice into a thick, ropy fluid; the lactic fer- ment, which produces lactic acid; and many others. If any one of these be placed in a suitable medium it produces its own particular change. Hence, the alcoholic ferment always produces alcohol; the vis- cous ferment, the gummy matter which thickens the fluid and renders it ropy. The effect is just as certain and definite with the minute organisms as with larger ones, the resulting growths having the character of the organism sown: just as we get a maize crop if we sow maize, pigeon-peas if we plant pigeon-peas, and cane if we plant cane.
From this it follows that to get the best results it is necessary to exercise some care in the selection of the ferment when it is desired to convert sugar into alcohol for commercial purposes ; for, if other ferments be sown into the fermenting liquid, other changes will go on at the expense of the sugar, less alcohol thus resulting.
Certain ferments require oxygen (air) for their 9
130 MANUAL FOR SUGAR GROWERS.
growth, hence their growth can be stopped by ex- cluding air, or hastened by admitting it. The acetic ferment belongs to this latter class, and thus in the manufacture of vinegar it is necessary to have free access of air to the fermenting liquid. The alcoholic ferment belongs to the former class, and thus can live and grow in vessels from which air is excluded.
In the case of alcoholic fermentation of cane sugar the changes take place in two stages: I. The sugar is rapidly converted into glucose or in- verted. This change is effected by a soluble fer- ment, “invertase,” secreted by the yeast-plant, the change only taking place if the solution is slightly acid, and is at once arrested if the solution is alka- line. This point is one well worth remembering by sugar-makers, as by tempering their juice as quickly as possible, and by keeping any juice which cannot be boiled at once slightly alkaline to the phenol-phthalein test, this inversion can be largely prevented. It is this inversion, of course, which prevents “sour” cane-juice yielding sugar when boiled, although it may have a high density when tested by the hydrometer before boiling. 2. The elucose thus produced is acted on by the yeast- plant, and converted into alcohol and carbonic-acid gas according to the following equation : Under the action of invertase,
CigH20,: so 2 OL = Robe cane-sugar and water become glucose. Under the action of the yeast-plant, C;H120¢ = 2CO2 + 2C,H,0, elucose becomes carbonic-acid gas and alcohol.
MANUAL FOR SUGAR GROWERS. 131
The presence of a large amount of alcohol arrests the development of the yeast-plant. Hence in the presence of a considerable amount of sugar the fer- mentation comes to an end before all the sugar is converted into alcohol; it is therefore wasteful to employ solutions which are too concentrated, as this results in loss of sugar.
When filter-presses are used in the manufacture of sugar there is no waste product to be converted into rum (the name given to the spirit produced from sugar-cane products) save molasses. This is mixed with water in such proportion that the resulting “wash ” has a density of about 8° B. The wash is set up to ferment in vats of various sizes, depending on the size of the distillery, 1,000 gallons being a convenient size. Fermentation, as a rule, soon sets in without the addition of any ferment. Bubbles of carbonic-acid gas rise briskly to the surface, the liquid becomes slightly heated, and the density rapidly diminishes, falling to about 1° to 2° B. when the process is completed. This process usually oc- cupies three or four days. This time could doubtless be shortened by adding to the fresh wash a small quantity of yeast or ferment taken from vats in which fermentation was active. It has been already stated that it is necessary that the solution be slightly acid in order that the cane sugar may be converted into glucose. It is usual, therefore, to add a small quan- tity of sulphuric acid to the wash to obtain this necessary condition. It is only necessary to add so much acid as will render the wash very slightly acid to litmus-paper, indicated by turning blue litmus-
132 MANUAL FOR SUGAR GROWERS.
paper slightly red. All waste products containing sugar, such as washings of various appliances, skim- mings, etc., should be sent to the distillery to be utilised in setting up wash.
A great deal has been said, though but little defi- nite seems to be known, about the production of a fine aroma and flavour inrum. This is no doubt due to the formation of various ethers and compound ethers during the process of fermentation. Good results in this direction appear to follow from set- ting up the wash at a higher density than 8° B., say from 10° to 13° B., allowing the fermentation to pro- ceed slowly until all fermentation ceases, after which the washis kept for twenty-four hours before distil- lation. Probably working in this way secondary fer- mentations set in, as the action of the alcoholic fer- ment becomes feeble. The subject is one which has been but little studied, and would repay further in- vestigation. There are, of course, two courses open to the distiller: one, to produce rum when flavour and aroma must be obtained even at some expense of sugar, time, and trouble ; the other, to make recti- fied spirit when quantity and freedom from aroma and flavour will be the objects aimed at.
When a solution of cane sugar is fermented under the most favourable conditions, 100 pounds of cane sugar yield 51.11 pounds of pure alcohol, or, in other words, slightly over 100 pounds of proof spirit, or 10.9 gallons; this is the theoretical yield, which is never reached in actual practice. With good apph- ances and careful working it ought to be possible to obtain from eighty to eighty-five per cent. of the
MANUAL FOR SUGAR GROWERS. 133
theoretical yield, or every 100 pounds of sugar in the wash ought to yield from eight and three-quayr- ters to nine and a quarter gallons of proof-spirit.
When the fermentation of the wash has ceased, the alcohol is recovered by distillation, an operation depending on the fact that alcohol boils at a lower temperature than water, so that, when a mixture of water and alcohol is boiled, the vapour which first escapes consists very largely of alcohol, the vapour containing more and more water as the boiling con- tinues, until at last it consists of little else than water. The simplest form of still in which the operation of distilling is conducted consists merely of a vessel in which the wash is boiled, provided with a long tube, usually coiled into a spiral form for convenience, into which the vapour passes and in which it is cooled as rapidly as possible ; this cooling is effected by placing the coiled tube in water.
The only improvement commonly employed in this class of still consists in introducing one or two vessels or retorts between the body of the still and the condenser or worm. The use of these is to in- tercept the heavier vapours, thus rendering the recti- fication more perfect at one operation than it would be if the whole of the vapour passed direct to the condenser worm and so into the receiver.
Alcohol having a density of .864, or 40 over-proof,*
* The term proof-spirit is derived from the curious method of testing in use many years ago. A little of the spirit to be tested was poured upon a small heap of gunpowder, and the spirit ignited. If, when all the spirit had burned away, the gunpow- der also took fire, the spirit was said to be ‘‘ above proof ;” if, on
134 MANUAL FOR SUGAR GROWERS.
is the usual strength of commercial rum. Spirit of a density from .864 to .900, or from 40 to 50 over- proof, is termed high wines, while weak spirit, from .900 to .967, or from 15 over-proof to 50 under-proof, is termed low wines, and from both of these spirit of full strength is recovered by redistillation. This redistillation is often economically effected by plac- ing a quantity of low wines in the first retort and high wines in the second, the heat of the vapour from the wash in the still driving the alcohol, in a high state of concentration, into the condensing- worm.
In large distilleries what are known as continuous stills are employed. There are a great many modi- fications of this kind of apparatus; the principles underlying their construction and method of work- ing will be understood from Fig. 20 and the follow- ing brief description.
The chief parts of the apparatus are: A, the wash-tank’; B, condenser; C, the rectifying -col- umn; D, the condensing-worm.
The wash flows, in the direction indicated by the arrows, from the wash-tank into the condenser, where it serves to cool the vapour which passes from the rectifying-column into the worm of the condenser ; from the condenser the wash, now par- tially heated, flows by means of a pipe into the rectifying-column. This contains a number of hori- zontal plates or discs, perforated, yet so arranged
the other hand, the quantity of water in the spirit was so great as to render the gunpowder too wet to burn, the spirit was said to be ‘*under-proof.’”’
. MANUAL FOR SUGAR GROWERS. 135
as to retain a thin film of moisture on the surface of each disc; the wash in its downward course over
STEAM FROM BOILER
[J OUTLET FOR EXHAUSTED WASH
Fic. 20.—Diagram of continuous still.
the perforated discs meets the ascending hot va- pours generated by means of steam admitted from a steam-boiler not shown in the figure. The more volatile portion of the wash—the alcohol—escapes through the pipe into the worm of the condenser, where it is condensed as already described. The less volatile portion passes downward into the cham- ber at the bottom of the rectifying-column, whence it is run off as it accumulates.
The exhausted residue from which the spirit has been distilled is known as dunder. It contains vari- ous mineral matters, as potash, phosphoric acid, ete., together with any sugar which has escaped fermen- tation. A certain quantity of it is usually employed, instead of water, in setting up fresh wash for fer- mentation, the unfermented sugar being thus saved,
136 MANUAL FOR SUGAR GROWERS.
while the mineral matter serves to supply plant- food, which is quite as necessary to the yeast-plant as to any other vegetable organism.
The value of rum depends largely on its flavour and aroma, and as the substances conferring the distinctive character are very volatile they are found in greatest quantity in the first runnings from the still; hence stills of the old or discontinuous type are often preferred, as by this means the first half of the returns, or any desired portion, can be kept separate in order to produce a spirit of first quality. From the continuous stills the spirit flows in a stream of almost unvarying quality, and in this case it is impossible to separate the product into portions differing in flavour and aroma.
Rum is usually coloured by means of burnt sugar. The colouring matter is prepared by heat- ing muscovado sugar in an iron pan until it is con- verted into caramel, having a fine black colour. When sufficiently heated the fire is withdrawn, and strong proof rum is added, the whole being briskly stirred meanwhile. This solution is added to rum in such quantity as to produce the desired colour.
MANUAL FOR SUGAR GROWERS.
137
TABLE SHOWING TEMPERATURE OF STEAM AT PRESSURES
Temperature, Fahrenheit.
Degrees, 212 215 220 225 230 235 240 245 250 260
FROM 0 TO 120 PoUNDS PER SQUARE INCH.
ure, pounds per square
inch.
Steam press-
Water boils 90
2.50 4.23 6.11 8.13 10.32 12.62 15.20 20.83
Temperature, Centigrade.
l oanlll aon of Exes) ae}
i.
104.
107.2 110.0 112.8 115.5 119 4 121.1 126.6
Temperature, Fahrenheit.
Degrees.
ure, pounds per square
Steam press- inch.
Temperature, Centigrade
A Ad
poh pane Co OO 0 -~2 09
145.3 148.8 154.4 159.9 165.5 Dele 176.6
138
MANUAL FOR SUGAR GROWERS.
List OF ELEMENTS WITH THEIR SYMBOLS AND COMBINING
ATA . << << Al. ANTINONGY 52.6 sds «oie Sb. APSE MEG a socal a. os As. Barn o625.2%4. Ba. Bimuthascels 1.2% Bi. IOEOH. Fo ole iccie. cae B. Bromine, | ono Set Br. Cagmirai 2 i452. Cd. PASM 4 22> eke Ne Cs. Calemem .2 2 o2enoe2 Ca. Cambor. . sh 540ioee C. Ceri. . 253% jnic Ce. CHiorment= 32%). 2 Ck Chremrgm< «6.45 = Cr. Coates ee wae kine ow Co. Coppers tis. s isk... Cu. Didymiigm: - +s. 5. 2 D. Er bramicy. 2 ode s.065 5 E. Plgorine =... sates F. Glucmunt<.. 4... dee Gl. Gold. 2 tee Au. Hydrogen gs os suie Fe Indinm. 3.4 2. ae Seas b AGAIMC S38" sates ce ‘a Bidinm ¢ jean ee.t ir: PEAR: 62 so ce eee Fe. Lanthanum ....... La. Ley a re ee ED: ap goes oe ss Li. Magnesium........ Mg. Manganese ........ Mn. Mereary 5.32. 5.5.0 <0 Hg.
WEIGHTS. 27.3 | Molybdenum ..... . Mo. NS Or eet IN ACACEN eile asic p xc % Ni. Cy SEIN O DTI: 2 ph, cc0e fs 2 ok Nb. Lae 4 Nitrogen 22 1). !: 62: N. D120 | Memigm 4.5... Os. PE) WOON 28 ote esse O. $0:0'| Palladium: -. =.2. 33 Pd. 112.0} Phosphorus ....... Fr 135.0: Piatinuni +, oi. fos... PE AQ0)|-Rotassium:... .¢o36 K. 12.0,| Rhodium... 2°. 226. Rh. 02.3 | Hubidium ... 224. Rb. 0,0: | RiUtheninm <2... Ru. Ho ak.| Selena x22 2 a ec Se. oe Ae LIGOW 27: «7. es ate oe Si. Gant Silvers ae es cto. 2 Ag. Of OL. SOG ui. ott. ec: Na. Ato -G | Stroutiqm .'2 2.6 2s <:. Sr. 19) | Salphur.y.3. sets... S. Ors | Lantalwim. \.. x12. «ct < Ta. 196575) Tellurium .2<.:.. 2 a: 4) Palais hoe ss Tl. Pte) | (Chori... 6c3 te ote Th. 1269 Pine OL ete ee Sn. 296;9 | TWataniums 32 04-00 Ta: 56.04) Tungsten... <..¢25-.% W. 92.6) Uraniwim 22:55. 52 o0¢ Uz. 206.9 | Vanadium, ..2..... V. Ou) SN GETAIR, Cs oe Betas V2 rot: EA Oe a aeietlee ene Zn. 54:0) | Zirconium? 3.35 23-6 Zr 200.0
MANUAL FOR SUGAR GROWERS.
TABLE OF DENSITIES, ETC., OF SACCHARINE
Specific gravity.
1.0000 1.0035 1.0070 1.0105 1.0141 1.0177
1.0213 |
1.0249
1.0286 |
1.0323 1.0360 1.0397 1.0435 1.0473 1.0511 1.0549 1.0588 1.0627 1.0667 1.0706 1.0746 1.0787 1.0829 1.0868 1.0909 1.0951
In one gallon.
(et
Pounds Pounds
| sugar. water. 0.0000 | 10.0000 0.0903 | 9.9447
0.1812 | 9.8888
0.2718 | 9.8332
0.3640 | 9.7770
0.4569 | 9.7201 0.5504 | 9.6626 0.6446 | 9.6044 0.7395 | 9.5465 0.8351 | 9.4879 0.9324 | 9.4276 1.0293 | 9.3677 1.1269 | 9.3081 1.2253 | 9.2477 1.3254 | 9.1856 | 1.4251 | 9.1239 1.5267 | 9.0613 | 1.6280 | 8.9990 1.7312 | 8.9358 1.8350 ; 8.8710 1.9396 | 8.8064 2.0452 | 8.7418 | 2.1513 | 8.6757 | 2.2583 | 8.6097 2.3661 | 8.5429 | 2.4749 | 8.4761
139
SOLUTIONS.
ge | ge | ai || Dione gallon bos Ee 25 Pounds Pounds AmMm|-a| We | sugar. water. 13.0 23.52} 1.0992 | 2.5853 | 8.4067 13.5 24.43 | 1.1034 | 2.6956 | 8.3384 14.0 25.35} 1.1077 | 2.8080 | 8.2690 “145 26.27 | 1.1120 | 2.9212 | 8.1988 | 15.0 | 27.19 | 1.1163 | 3.0342 | 8.1288 | 15.5 | 28.10 | 1.1206 | 3.1488 | 8.0572 “16.0 29.03 | 1.1250 | 3.2658 | 7.9842 “16.5 29.95 | 1.1994 | 3.3885 | 7.9105 17.0 30.87 | 1.1339 | 3.5003 | 7.8387 | 17.5 | 31.79 | 1.1883 | 3.6186 | 7.7644 (18.0 32.72 1.1429 | 3.7395 | 7.6895 (18.5 33.65 | 1.1474 | 3.8610 | 7.6130 19.0 34.58 | 1.1520 | 3.9836 | 7.5364 (19.5 35.50 | 1.1566 | 4.1059 | 7.4601 20.0 36.44) 1.1613 | 4.2317 | 7.3813 20.5 37.87} 1.1660 | 4.3573 | 7.3027 21.0 38.30) 1.1707 | 4.4837 | 7.2238 (21,5 39.24 1.1755 | 4.6126 | 7.1424 (22.0 40.17, 1.1803 | 4.7412 | 7.0618 99.5 | 41.11| 1.1852 | 4.8723 | 6.9797 | 23.0 42.05 1.1901 | 5.0043 | 6.8967 93.5 42.99 1.1950 | 5.1373 6.8127 “94.0 | 43,94 1.2000 | 5.2728 | 6.7272 24.5 44.88 1.2050 | 5.4080 | 6.6420 25.0 | 45.83 | 1.2101 | 5.5458 | 6.5552
1.2152 | 5.6847 | 6.4673
| 25.5. 46.78
140 MANUAL FOR SUGAR GROWERS.
TABLE OF DENSITIES, ETC.— Continued.
| =e
| In one gallon. | | ¥
*
male al) 3S S| =] Ls | Inone gallon.
o wo ees o a eis .
eal ge koe | ol ea gs | ay ae
we 5, | $= Pounds Pounds) | $s | on == |Pounds Pounds
S3\|22 | we sugar. water.|/Ag|@2| wh | su t
As = gar. : fea) a gar. water. | |
26.C | 47.73 | 1.2203 | 5.8244 | 6.3786 | | 39.0 | 73.23] 1.3714 | 10.0427 | 3.6713
26.5 48.68 1.2255 5.9657 | 6.2893 | 39.5 | 74.25) 1.3780 10.2216 | 3.5584 1.2308 6.1084 | 6.1996 | 40.0 | 75.27| 1.3846 | 10.4218 | 3.4249 1.2361 6.2534 | 6.1076 | | 40.5 | 76.29| 1.3913 | 10.6142 | 3.2988
28.0 51.55 1.2414 6.3994 | 6.0146 | | 41.0 | 77.82] 1.3981 | 10.8101 | 3.1709 93.5 | 52.51 1.2468 6.5469 | 5.9211 | | 41.5 | 78.35 | 1.4049 | 11.0073 | 3.0417
|
29.0 | 53.47 1.2522 | ,6.6955 | 5.8265
29.5 | 54.44 1.2576 | 6.8463
| | | 30.0 | 55.47 1.26382 7.0069 5.6251 | | 43.0 81.47 | 1.4267 | 11.6233 | 2.6437 | | } |
30.5 56.37 1.2687 | 7.1516 | 5.5354 | 43.5 | 82.51) 1.4328 | 11.8220 | 2.5060 31.0 57.34 1.2743 | 7.3068 | 5.4362 | | 44.0 | 83.56 | 1.4400 | 12.0826 | 2,3674 31.5 58.32 1.2800 7.4649 5.3351 | 44.5 | 84.62 1.4472 | 19.2462 | 2.9958
ne ro [—}
79.39 | 1.4118 | 11.2082 | 2.9098 5.7297 | | 42.5 | 80.43 | 1.4187 | 11.4106 | 2.7764
32.0 59.29 1.2857 7.6229 5.2341 | 45.0 | 85.68 | 1.4545 12.4621 | 2.0829 32.5 60.27 | 1.2915 | 7.7838 | 5.1312 | 45.5 | 86.74) 1.4619 12.6805 | 1.9885 33.0 61.25 1.2973 | 7.9459 5.0271 | | 46.0| 87.81 | 1.4694 12.9028 | 1.7912 33.5 62.23 1.3032 8.1098 ; 4.9222 | 46.5 | 88.88| 1.4769 | 13.1266 | 1.6424 34.0 63.22 | 1.3091 | 8.2761 | 4.8149 | 47.0) 89.96 | 1.4845 13.3395 | 1.5195 (84.5 64.21 | 1.3151 | 8.4442 | 4.7068 | 47.5 | 91.03 1.4929 | 13.5834 | 1.3886
35.0 65.20 1.3211 8.6135 4.5975 | 48.0 | 92.12 1.5000 (13.8180 | 1.1820
35.5 66.19 | 1.3272 | 8.7847 | 4.4873 | | 48.5 | 98.21 1.5079 | 14.0551 | 1.0239 36.0 67.19 | 1.3333 | 8.9584 | 4.3746 | 49.0 94.30 | 1.5158 14.2939 | 0.8641 36.5 68.19 | 1.3395 | 9.1340 | 4.2610 | 49.5 95.40 | 1.5238 | 14.5370 | 0.7010 37.0 | 69.19 | 1.3458 | 9.3115 | 4.1465 | 50.0 | 96.51. 1.5319 | 14.7843 | 0.5347
| | 37.5 70.20 | 1.3521 | 9.4917 | 4.0293 | 50.5 97.62 1.5401 15.0344 0.3666
38.0 | 71.20 | 1.3585 | 9.6725 | 3.9125 51.0 | 98.73 | 1.5484 15.2873 | 0.1967 38.5 | 72.22 | 1.3649 | 9.8573 | 3.7917 | | 51.5 | 99.85 | 1.5568 | 15.5446 | 0.0234
LN DE x
ACETIC acid, formation of, 129
Acetic ferment, 129, 130
Acid phosphate of lime, 68, 69
Acids, those in soil must be neu- tralised, 27; cause of inversion, 99; use in tempering, 99
Agriculture, science in, v, vi, 1, 18
Air, influence on root-growth, 18, 19, 27, 52, 33; putrefactive pro- cesses in the, 128
Albumen, amount in cane-juice,
85; precipitation in clarifying, |
86, 90
Alcohol, formation of, 124-127, | 129, 180 ; conversion into acetic |
acid, 127; yield from cane sugar, 152, 183; condensation of, 155 Alcoholic ferment, 129, 130 Alum, extracted from beet mo- lasses, 126
-Alumina, presence in plants, 21;_
amount in pen manure, 64; amount in filter-press cake, 93 Ammonia, insoluble in water, 30; retention by soil, 30, 63 ; loss of, from pen manure, 59; forma- tion from nitrogenous matter, 62; ratio of sulphate of ammonia to, 72
Ammoniacal manures, restrictions on use of, 48
Analysis, purchase of chemical manures on, 68, 71, 72
Anderson’s analysis of pen ma- nure, 64
Animal charcoal, use in decolour- isation, 115, 116
Animal excreta, a nitrogenous manure, 25, 26. See also PEN MANURE.
Animal life, dependence on vegeta- ble life, 12
Animal manure., See PEN Ma- NURE.
Animals, care of, 60
_‘** Annales Agronomiques,” quoted,
58, 59
Antigua, analysis of volcanic soil at, 23
Arrowing, 44
Arrowroot, 14
Aruba, phosphate beds of, 69
Ash constituents obtained from and voided by cattle, 58
Ashes, 47
Atmosphere, composition of, 11, 25; action on plant-food, 24; the source of carbon for plants, 25; absorption of nitrogen from, by Leguminose, 28
BAcTERIA, assimilation of atmo- spheric nitrogen by, 29
142
Bacteria-cells of Leguminose, 29 Balling’s hydrometer, 119 Barley, consumption of plant-food
INDEX.
head of sugar, 101, 102; ascer- taining richness of, 117-121; fer- mentation of, 127
by, 22; value of manure pro- Cane-mills, their forms, principles,
duced from consumption of, by cattle, 64
Barometer, use of, 104
Basic phosphate of lime, 70, 71
Basic slag, 70, 71
Bean plant, its mode of feeding, 28
Beans, value of manure produced from their consumption by cat- tle, 63; value as green dressing, 65
Beet molasses, analysis of, 125, 126
Beet sugar, different processes ap- plicable to, from those for cane sugar, 125
Begass. See MEGAss.
Bengal bean, value as green dress- ing, 65
Bleaching agents, 97, 113, 116
Blood, a nitrogenous manure, 26
Blow-up, 115
Boiling, 99; theory of, 103, 104; how produces molasses, 123
Bone, constituents of, 57
Bones, use as manure, 68
Borers, 45
Botany, connection with agricul- ture, 1
Brix’s hydrometer, 119
Budding of yeast-plants, 128
Burnt sugar, use of, 156
CAJANUS INDICUS, peculiarity of, 28; value as green dressing, 65 Calcareous soil, analysis of, 25;
experiments on, 49 Calcium, 2 Canada, phosphate beds of, 69 Cane-juice, analysis of, 85; amount required to make a hogs-
and use, 75-81
Cane sugar, amount in cane-juice, 55; formula of, 98; amount in molasses, 122; effect of glucose on, 123 ; combinations with, 125 ; alcoholic fermentation of, 150; yield of alcohol from, 132, 133
Canned foods, how preserved, 127,
128 Capillary attraction, 19 Capon-tail, 44 Caramel, 136
_Carbo-hydrates, 6
Carbolic acid, use of, 48
Carbon, its presence in plants, 2, 5, 6, 13; its symbol, 3; source of, 11,12; proportion in sugar, 12; essential to plant-food, 25
Carbonate of ammonia, 30, 31, 48, 59
Carbonate of lime, composition of, 16; presence in soil, 27, 31, 48; in decolorisation process, 114, 115
Carbonate of potash, presence in soil, 30, 31 ; how obtained, 67
Carbonation, decolorisation by, 114, 115 Carbon-dioxide. See CARBONIC- ACID GAS.
Carbonic-acid gas, its presence and use, 11,12; use in decolorisation, 114, 115; use in recovery of sugar from molasses, 125; pro- duction from glucose, 130
Carnallite, use as manure, 65
Cassava, 14
Catch-pit for liquid manure, 62
Cattle, injurious effect of, on wet lands, 27; West Indian practice
INDEX.
in herding, 61; choice of food for, in relation to manure, 63 ; filter-press cake as feed for, 94; molasses as food for, 124
Cattle-pens, recommendations as to, 62
Cells, 4
Cellulose, 6
Centrifugal process, 111, 112
Chalk. See CARBONATE OF LIME.
Charcoal. See ANIMAL CHAR- COAL.
Chemical manures, proper and im- proper uses of, 32, 53
Chemical symbols, 3; table of, 138
Chemistry, connection with agri- culture, 1
‘‘Chemistry of the Farm,” quoted, 30, 57
Chloride of magnesia, presence in carnallite, 68
Chloride of potash, presence in carnallite, 68
Chlorides, soluble in water, 30; found in drainage-waters, 31
Chlorine, 2, 21, 22
Chlorophyll, 12
Clarification, 85, 90, 119, 120
Clay, its origin, composition, and properties, 16, 17; excessive density of some, 52; mixed with nitrate of soda, 72
Clover hay, value of manure pro- duced from its consumption by cattle, 64
Coal, consumption of, in evapora- tion of water, 110
Coal-gas, manure products from, 12
Colic, induced in cattle, 94
Colloids, 10
Colouring-matter, amount in cane- juice, 85; in sugar, 97
Colour of sugar, 112, 116
143
Combining weights of elements, 138
Concentration, 99, 100, 104-108, 110, 114
Condenser, 134, 135
Condensing-worm, 134, 135
Condition, maintained by pen ma- nure, 56
Continuous stills, 184-136
Coolers, 100
Coprolites, 69
Cotton-seed cake, value of manure produced from its consumption by cattle, 63 ; use as food and as manure, 71
Cows, nitrogen and ash constitu- ents obtained from and voided by, 57, 58
Cracking-point of scum, 91
Cross-holeing, 41
Crystallisation, 99-101, 112, 118, 128
Crystalloids, 10
Curing-house, the, 102
Curing sugar, 111-113
105-108,
DECAY, causes of, 127
Defecator, use of, 91, 94
De Mornay mill, 77, 78
Densities of saccharine solutions, 139, 140
Density, 117
Dew, 20
Diffusion process, 81-84
Digging, 18
Disease, prevention of, 45; eradi- cating by burning trash, 53
Distilleries, 125, 126
Distilling, 91, 151-136
Dodds’ Experimental Station, 49, 50
Double-crushing, 81, 84
Doubling, 108
Drainage, principles, methods,
144
INDEX.
etc., of, 33-39; loss of nitrates | Forking, 18
by, 72 Drainage-water, plant-food in, 30 Drying filter-press cake, 95, 96 Dumb returner, 76-78 Dunder, 185
Economy, importance in colonial agriculture, 72
Elements, the, 2 et seg. ; table of, 138
England, coprolites in, 69
Ethers, formation of, in distilla- tion, 152
Evaporation, 98-100
Excise regulations, obstacle in way of using molasses, 124, 125
Excreta of animals. See PEN Ma- NURE.
FALSE grain, 107, 108
Farm-yard manure. NURE.
Fat, constituents of, 57; amount in cane-juice, 85
Fawcett, Preston, & Co.’s mill, 77, 78
Felspar, 16, 17
Fermentation, effect on molasses, 124; causes of, 127; secondary, 132
Ferments, cause of inversion, 99
Ferrous sulphate, use as manure, 73, 74
Fertility of soil, necessary condi- tions for, 27
Filter-press, its use and product, 92-97
Filter process, economy of, 131
Fish, how preserved, 127, 128
Fletcher & Le Blanc’s four-roller mill, 76
Florida, phosphate beds of, 69
Forest soil, 24
See Pen Ma-
Fossil manures, 69
Fruit, how preserved, 127, 128
Fungus, destruction of, by burning trash, 53
GEMMATION, reproduction of yeast-plants by, 128
Gilbert, Dr., table of value of ma- nure, 63, 64
Glucose, amount in cane-juice, 85 ; formation of, and formula, 98; production of, 100; amount in molasses, 122; effect on cane su- gar, 123 ; non-combining proper- ties of, 125; action of yeast- plant on, 130; conversion of cane sugar into, during alcoholic fer- mentation, 150
Glucose ratio, the, 102, 103
Graining, 105-108
Gravel, 17
Green dressings, nitrogenous char- acter of, 25, 26; use of, 41, 65, 66
Griffiths, Dr., quoted, 58, 59
Guano, its composition and use, 70
Gypsum, mixed with nitrate of soda, 72
Hatt, E. R., experiment by, 44
Harrison, Prof., estimate of matter removed from soil by cane crop, 49, 50; analysis of pen manure, 64
Hay, value of manure produced from consumption of, 64
Heart, 18, 52
Heat, influence on soil, 18; cause of inversion, 99
High wines, 154
Holeing, 40, 41, 64
Horse-hoes, use of, 39
INDEX.
Humus, 17 et seg.; produced by certain manures, 26, 41, 62; value of Leguminose in formation of, 30
Hydraulic attachment to cane-mill, 78-80
Hydraulics, principles of, 78-80
Hydrochloric acid, use of, in anal- ysis of soil, 22, 24
Hydrogen, 2, 3, 5, 6, 12, 26
Hydrometer, its construction, prin- ciples, and use, 117-121
INVERSION, a result of under-tem- pering, 89; cause of production of molasses, 99, 101 ; rapidity of, 100; rate of, in making musco- vado sugar, 102; amount in vacuum-pan process, 103; cause of rapid, 104; danger of, in bleaching, 114; formation of glu- cose by, 123 ; how prevented, 130
Invertase, 130
Invert sugar, formation of, 98
Iron, 2, 17, 21, 23, 25; deficiency of, 53; removal of phosphorus from, 70
KAINIT, its source and value, 67 Keeping cattle to make manure, 60
Lactic acid, formation of, 129
Lawes, Sir J. B., table of value of manure, 63, 64
Leaf of sugar-cane, 10-14
Leaves, value as manure, 68
Lees pond, the, 95
Leeward Islands, average expres- sion of cane-mills in, 81
145
Liebig, Baron von, treatment of bones, 68, 69
Light, influence on plauts, 13; in- fluence on soil, 18
Light-colored sugar, manufacture of, 89, 90
Lime, essential to fertility of soil, 17, 21, 25; quantity removed from soil by a crop, 22; amount in soil, 23, 24; retainer of phos- phoric acid, 30; deficiency of, 33; as manure, 47; amount in mould from watercourse, 54; amount in pen manure, 64; employed to remove phosphorus from iron, 70; use in clarifying cane-juice, 86; use in decolorisation, 114, 115; combination of cane sugar with, 125
Lime-water, use of, 45
Line and marks, use of, 45
Linseed cake, value of manure pro- duced from its consumption by cattle, 65
Litmus-paper, testing with, 87
‘* Louisiana Planter, The,” quoted, 82 ;
Low wines, 134
MACHINE weeding, beneficial ef- fects of, 42
Magnesia, essential to fertility of soil, 17, 21; quantity removed from soil by a crop, 22; amount in soil, 23, 24; deficiency of, 33 ; amount of, in mould from water- course, 54; amount in pen man- ure, 64; presence in kainit, 67; amount in filter-press cake, 93
Magnesium, 2
Leguminose, peculiarities of for- | Manganese, 2, 21
mation, 28; value for green dressings, 29, 65; consumption of nitrogen by, 25, 28, 29
10
Mangel wurzel, value of manure produced from its consumption by cattle, 64
146
Manure, experiments on nitrogen in, 28, 59; rotting, 60; influence of food of animals on, 63 ; use of concentrated chemical, 63; table of values, 63, 64; filter-press cake as, 96, 97
Manures, summary of those used in West Indies by sugar- growers, 56-74 ; chemical, 66-74
Manuring, 21, 24, 25, 41, 47, 50
Marble, power of plant roots over,
22; origin, composition, and prop- |
erties, 16, 17; as manure, 47
Marling, an improvement to some soils, 51
Masse cuite, 105, 107, 108, 112
Matter, indestructibility of, 1 et seq.
Meadow hay, of plant-food by, value of ma- nure produced from its con- sumption by cattle, 64
Meat, how preserved, 127, 128
Megass, 75, 77, 80, 81
Microbes, action of, 26, 29
Microscope, use of the, 4
Milk, nitrogen consumed in form- ing, 57-59; how preserved, 127, 128
Mineral acids, use in tempering, 99
Mineral matter, amount in cane- juice, 85; amount in molasses, 122
Mineral phosphates, 69
Mirlees’ four-roller mill, 77
Moisture, necessary to fertility of
consumption 99.
wy
soil, 27, 33, 35, 36; necessary in| soil for sugar-cane, 33 ; amount |
in pen manure, 64; amount in filter-press cake, 95
Molasses, reduced production of, under phenol-phthalein process,
89; production due to inversion, | 99; drainage of, 101, 102 ; centri-
INDEX.
fugal process for removing, 111, 112; reboiling, 112, 118; its pro- duction, proportions, and use, ~ 122, 126; production of rum from, 1381 Mole-crickets, destruction of, by burning trash, 53 Mono-phosphate of lime, 69 Mono-saccharate of lime, 114 | Monte-jus, its use, 92 Montserrat, analysis of volcanic soil at, 25 | Mould from watercourses, 54, 55 Multiple-effect evaporation, 108, 111 _Muntz’s chemical researches, 26 _Muntz-Girard experiments on ni- trogen, 58, 59 Muriate of potash, presence in carnallite, 68 Muscle, constituents of, 57 Muscovado process, 86, 90, 99, 102; method of estimating amount of sugar from cane-juice, 120, 121; influence of glucose in, 123 Muscovado sugar, character of mo- lasses from, 122
}
NATURAL drainage, 33, 35 Nitrate, conversion of nitrogen
| into, 26; amount in soil, 27, 28,
48
| Nitrate of soda, 28; its composi-
tion, origin, and use as manure,
31, 71, 72
Nitrates, soluble in water, 30; found in drainage-waters, 31; formation of, from nitrogenous matter, 62
Nitric acid, 26
Nitrogen, 2, 3, 5, 27, 31, 48; con- stituent of the atmosphere, 11, 25, 29; essential to fertility of soil, 17; amount removed from
INDEX.
soil by a crop, 22; how absorbed by plants, 26, 28, 29; chemical changes in, to render availabl- as manure, 26; deficiency of, 33 ; quantity removed from soil by cane crop, 50; amount in mould from watercourse, 54; presence in pen manure, 56; material in animal growth, 57; quantity ob- tained from and voided by cattle, 57; Muntz-Girard experiments on, 58, 59; loss in rotting ma- nure, 61; loss from overheating manure, 62; amount in pen ma- nure, 64; supplied by leguminous crops, 65; supplied by seaweed, 66; constituent of bones, 68; constituent of guano, 70; pro- portions in nitrate of soda and sulphate of ammonia, 72; amount in filter-press cake, 93, 96
Nitrogenous manures, their compo- sition and use, 31, 71, 72
Oats, consumption of plant-food by, 22; value of manure pro- duced from their consumption by cattle, 64
Oil-cake, use as food and as ma- nure, 71
Open-fire evaporation, 100
Open-trench draining, 34
Organic acids, use in tempering, 99
Osmose, 9, 10, 82
Oxen, nitrogen and ash constitu- ents obtained from and voided by, 57, 58
Oxide of alumina, 30
Oxide of iron, 21, 23, 30; amount in mould from watercourse, 54; amount in pen manure, 64; amount in filter-press cake, 95
Oxide of manganese, amount in mould from watercourse, 54
147
Oxygen, 2, 3, 5, 6, 11, 12, 26; nec- essity of, for some fermenta- tions, 129, 130
PARASITES, destruction by burning trash, 53
Pea-plant, its mode of feeding, 28
Peas, value of manure produced from their consumption by cat- tle, 63; value as green dressing, 65
Pen manure, its use, constituents, etc., 25, 26, 41, 56-64, 66
Permanent water-level, 35
Perspiration, quantity of ash con- stituents voided by cattle in, 58
Phaseolus mungo, value as green dressing, 65
Phenol-phthalein, use of, 87-90, 113, 180
Phosphate of lime, 16; effect of plant-roots on, .22; constituent of bones, 68; where found, 69; amount in filter-press cake, 93, 94, 96; in decolourisation pro- cess, 115
Phosphates, 21, 70; insoluble in water, 30; when to apply, 47; injured in burning of trash, 53; material in animal growth, 57; dressing with, to follow green crops, 65; importance of keeping up supply of, 66
Phosphatic manures, their compo- sition, and use, 68-71
_Phosphorie acid, 17, 21-25; reten-
tion by soil, 50; deficiency of, 30; amount of, in mould from watercourse, 54; in pen manure, 56, 64; constituent of basic phos- phate of lime, 70, 71; precipita- tion in under-tempering, 94; de- colourisation by, 114, 115; con- stituent of dunder, 135
148
Phosphoric anhydride, quantity removed from soil by cane crop, 50
Phosphorus, 2; removal of, from iron, 70
Pigeon-pea, peculiarities of forma- tion, 28; value as green dressing, 65
Pigs, nitrogen and ash constituents obtained from and voided by, 57, 58
Pipe drains, 36-38
Plant-food, 6 et seq. ; proportions in soil, 21 ef seg. ; consumption by various crops, 22; amount soluble in dilute acid, 25; avail- able and slowly available, 24; exhaustion of, 25 ; how produced by microbes, 26; constituents soluble in water, 30; produced from trash, 53; in mould from watercourses, 54
Planting, 40, 42-47, 51, 52
Plants, respiration of, 12; transpi- ration of, 13; influence of light on, 13; death of, 15
Plant-tops, 43-45
Ploughing, 18, 39, 40, 52, 53
Polariscope, use of the, 99
Polariscopic test, dependence on proper draining, 101
Potash, 17, 21-25, 48; insolu- ble in water, 30; retention by soil, 30; deficiency of, 33; when to apply, 47; quantity removed from soil by cane crop, 50; fused with silica in burning trash, 53; not created by burning trash, 53 ; in mould from watercours:, 54 ; in pen manure, 56, 64; material in animal growth, 57; loss of, in rotting manure, 61; dressing with, to follow green crops, 65; importance of keeping up supply
INDEX.
of, 66; its sources and use, 66, 67; sulphate preferable to chlor- ide, 68; constituent of guano, 70; amount in filter-press cake, 93; constituent of dunder, 135; re- covery of, from beet-sugar, 125; amount in beet molasses, 126; amount in cane molasses, 126
Potassium, 2, 3
Potassium nitrate, 26
Potatoes, consumption of plant- food by, 22
Prairie soil, 24
Precipitated phosphate, 69
Proof spirit, origin of the term, 183, 134
Proof-stick, the, 106
Protoplasm, 6
Putrefaction, causes of, 127
RAIn, influence on soil, 18
Ratoons, 42, 44, 45, 51, 52
Reaping, 51
Rectified spirit, when to make, 132
Rectifying-column, 184, 135
Redistillation, 154
Rocks, classes of, 16
Root, of sugar-cane, 6-10 ; powers of assimilation of minerals, 21, 22
Root-cap, the, 7, 8
Root-growth, 35, 56
Root-hairs, 7-10, 32
Rootlets, growth of, 47
Root-nodules, 28, 29
Roots, growth of, 8
Root-tips, in clay soils, 32
Roth, Henry Ling, observations of, 7
Rothamsted, experiments ducted at, 57, 58
Rule of thumb, displaced by mod- ern agriculture, vi
Rum, manufacture, 91; flavor and aroma, 132; strength of com-
con-
INDEX.
mercial, 184; value, 186; how coloured, 136
SACCHARINE solutions, table of densities of, 18, 159, 140 Saccharometer, its construction, principles, and use, 117-121 Sachs, Prof., experiment by, 22 Salt, presence in kainit, 67 Saltpetre, 26
Sand, origin, composition, and properties, 17; power of retain- ing food constituents, 30;
amount in filter-press cake, 95 Sap, concentration of, 14 Schlosing’s chemical researches,
26 Science, connection with agricul-
ture, v, vi, 1 Scum, formation of, 90, 91 Scum-cake, its manufacture and
use, 92-97 Seaweed, use as manure, 66 Sedimentary soil, analysis of, 23 Selection of plant-tops, 43-45, 47 Setting up the wash, 91 Sheep, nitrogen and ash constitu-
ents obtained from and voided
by, 57, 58 Shier, Dr. John, test for clarifying,
86, 87 Silica, 17, 21-23, 30; fused with
potash in burning trash, 53;
amount in mould from water-
course, 54; amount in filter-
press cake, 93 Silicate of alumina, 16, 30 Silicon, 2 Silting of drains, 38 Skegel’s mill, 77 Soda, 21, 22;
press cake, 93 Sodium, 2 Sodium nitrate, 26
amount in filter-
149
Soil, origin, composition, and prop- erties, 15 e¢ seg. ; necessary con- ditions for fertility, 17, 18, 27; porosity of, 19-21; plant-food in, 21 et seg. ; analysis of, 22 ef seg. ; weight of, 23; presence of mi- crobes in, 26; defects in, 27; importance of air to, 27; sterili- zation of, 29; power of retaining food constituents, 30; nitrifying organism of, 51; condition of, 32; proper conditions of, 32; drainage of, 33-59; cold or wet, 34; waterlogging, 35, 42 ; experi- ments on, 48; matter extracted from, by cane crop, 49, 50; re- turn of matter to the, 50; a use- ful agent in fixing ammonia, 63 ; improvement of stiff clay, 66; non-retentive of nitrates, 72
Sombrero, phosphate beds of, 69
Soup, how preserved, 127, 128
Specific gravity, 117
Sports, 45
Stand-overs, 42
Starch, 6, 12-14; production of, by plants, 12
Starch-cells of leguminose, 28, 29
Steam, temperature of, under vari- ous pressures, 157
Steam pans, 100; character of mo- lasses from, 122
Stem, functions of, 14
Stills, 183-136
Stomata, 11
Striking the pan, 100, 102
Strontia, combination sugar with, 125
Subsiding, 114, 115
Subsoil draining, 54-39
Sugar, proportion of carbon in, 12; amount in filter-press cake, 94; chemistry of, 98 ; conversion into alcohol, 129
of cane-
150
‘* Sugar,” quoted, 84, 86-88 Sugar-cane, its structure, 4 et seq. ;
method of propagating, 6; root |
of, 6-10; necessities of, 33 ; cul- tivation, harvesting, etc., of, 40- 55
‘*Sugar-Cane, The,” quoted, 82
Sugar industry, necessity for lit- erature of, v, vi
Sulphate of alumina, use with beet molasses, 12, 126
Sulphate of ammonia, its composi- tion, origin, and use as manure, 31, 48, 49, 71, 72
Sulphate of iron, use as manure, 73, 74
Sulphate of lime, 31
Sulphate of potash, 47; presence in kainit, 67
Sulphur, 2, 5, 22
Sulphuric acid, 17, 21, 23, 49; treat- ment of bones with, 68; forma- tion of, 115; use in distillation, 181
Sulphurous acid, use in syrup, 90, 113, 114
Sunlight, influence on soil, 18
Superphosphate, compared with filter-press cake, 96
Superphosphate of lime, 47, 48, 69 ; an acid manure, 70
Surface draining, 34
Sutherland, J., experiment by, 44
TEMPERATURE, effect ou fertility of soil, 27
Tempering, 86-90, 99; care neces- sary to keep down molasses, 123
Termites, destruction of, by burn- ing trash, 53
‘*Text-Book of Botany,’’ 22
Thermometer, guide for ‘‘ strik- ing” the pan, 100; part of vacu- um-pan apparatus, 106
INDEX.
Thomas phosphate, 70
Thompson & Black’s rollers, 77
Tile draining, beneficial effects of, 42
Tile drains, 37-39
Tillage, importance of, 16, 19, 21, 27; results of careful, 50
Tramways, objections to use of, on sugar estates, 60
Transpiration of plants, 13, 14
Trash, removal and use of, 51-54
Trash-turner, 76
Tri-calcium phosphate, 69, 70
Triple-crushing, 81, 84
Triple-effect evaporation, 108-110
Tropical climate, conducive to fer- tility, 27 ; increases nitrification, 31; use of manure in, 61
Turnips, consumption of plant- food by, 22; value of manure produced from their consumption by cattle, 64
auxiliary
UNDER-TEMPERING, results of, 89, 94 Urine, value as manure, 68
VACUUM gauges, 106
Vacuum pan, use of the, 103-109; character of molasses from, 122; influence of glucose on process, 128
Vegetable life, 6 et seg. ; depend- ence on animal life, 12
Vegetable tissue, composition of, 4 et seg. ; the decomposition of, 5
Vinegar, free accessof air neces- sary to manufacture of, 130
Virgin soil, 25
Viscous ferment, 129
Voelcker’s analysis of pen manure, 64
Volcanic soil, analysis of, 23
INDEX.
WARINGTON’S chemical researches, 26; ‘‘Chemistry of the Farm” quoted, 30; chemical analyses of, 57, 58
Warmth, influence on soil, 18
Wash, 151-135
Wash-tank, 134, 135
Waste products, utilized in distil- lation, 132
Water, composition of, 3; influ- ence on root-growth, 18, 19; constituents soluble in water, 30; amount in cane-juice, 85; boiling-point under various press- ures, 104; coal consumed in evaporation of, 110; amount in molasses, 122
Watercourses, mould from, 54, 55
Wax, amount in cane-juice, $5
Weather, influence on soil, 15 ef seg., 18, 52
151
Weeding, beneficial effects of, 45, 50, 51
Weeding-machines, 39, 51
West Indies, economy of purchas- ing manures for, 67; conditions necessary to success of sugar in- dustry in, 111
Wheat, consumption of plant-food by, 22; value of manure pro- duced from its consumption by cattle, 64
Wood ashes, 68
Woolly pyrol, value as green dress-
* ing, 65
value aS manure,
YEAST-PLANT, growth of, 128, 129; development arrested by alcohol, 131; necessity of plant-—food for, 136
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TELEPHONE LINES AND THEIR PROPERTIES.
By Prof. W. J. Hopxins, of the Drexel Institute, Philadelphia. With numerous Illustrations. 1I2mo. [March, 1893.
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ELEMENTARY PHYSICS.
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LESSONS IN ELEMENTARY SCIENCE.
LONGMANS’ OBJECT LESSONS. Hints on Pre- paring and Giving Them. With full Notes of Com- plete Courses of Lessons on Elementary Science.
By Davip SALMON, Principal of the Training College, Swansea ; Revised and Adapted to American Schools by JOHN F. WOODHULL, Professor of Methods of Teaching Natural Science in the New York College for the Training of Teachers. I2mo. 246 pages. 152 Illustrations. Mailing Price, $1.10.
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