GIFT OF
Mrs. A. M. Duperu

f***, AMD up era

LU Wl

FIG. 47.

x FIG. 48.

FIG. 45.

FIG. 53.

&L ax MAR 1 0

CANE SUGAB:

A TEXT-BOOK ON THE AGRICULTURE OF THE SUGAR CANE,

THE MANUFACTURE OF CANE SUGAR, AND THE

ANALYSIS OF SUGAR HOUSE PRODUCTS;

TOGETHER WITH

A CHAPTER ON THE FERMENTATION OF MOLASSES.

SUGAR TECHNOLOGIST AT THE EXPERIMENT STATION OF THE
HAWAIIAN SUGAR PLANTERS' ASSOCIATION ;

Author of " Sugar and the Sugar Cane"

NORMAN RODGER,

ALTRINCHAM

(MANCHESTER) .

1911.

ALL EIGHTS EESERYED.

(Entered at Stationers' Hall.)

F 1 1HE absence of any recent English literature dealing with the sugar caneT

which prompted me to compile " Sugar and the Sugar Cane" can no longer be

offered as a reason for the production of an extended textbook on cane sugar.

During the last decade the treatises of Geerligs, and of Jones and Scardr
which specialize on cane sugar manufacture, have appeared ; the detailed work of
Ware on beet sugar manufacture contains much that is equally applicable to the
sister industry ; new editions also have been produced of Spencer's Handbooks,
and of Newlands' Text-book. With so detailed a library available reasonable
doubt may be felt as to the advisability of offering to the sugar public yet another
compilation.

My experience of the cane sugar industry has been divided between the
positions of chemist, of factory manager, of supervising chemist, and of sugar
technologist in a large Experiment Station; and as in addition it has been spent
in three sugar producing districts of widely variant character, it may possibly
have fitted me to take a broad view of the salient points of the industry, and so to
select for detailed treatment its more important aspects. Access, also, to a well-
stocked library has enabled me to compile and present information not accessible
to others less favourably situated.

The advisability of a chemist devoting considerable space to the botany, agri-
culture and pathology of the cane may be questioned. I, however, found it
impossible to live on plantations without taking a keen interest in, and attempting
to obtain something more than a smattering of, all phases of the production of
cane sugar. I feel, then, that some account of these matters may serve to fill a
lacuna in English technical literature.

It was only after mature consideration that I decided to let the chapter on
' Pests and Diseases' appear in its present form; the entomologist and the plant
pathologist will be unlikely to refer to it for information. The account there
given may serve, however, to stimulate interest in these destructive agencies, and
in the means for their control, particularly in that known as the ' natural
method,' which has been developed with such striking success in the Hawaiian
islands by Koebele, Craw, Perkins, and their associates.

In selecting from the material at hand for use in this compilation, I have
used much that is academic, as opposed to that of practical interest ; although
this selection may cause the compilation to appear too 'theoretical,' yet this
reasoning has not made me depart from my ideal of inserting what I thought
ought to appear, rather than what other people might think ' practical.'

iii.

CANE SUGAR.

In writing of matters which I can only hope to touch on as an amateur, there
is danger of serious error. I have been fortunate, then, in the opportunity of
having the earlier portion of my manuscript read by friends and colleagues, Mr.
C. F. Eckart, Dr. E. C. L. Perkins, Mr. L. Lewton-Brain, and Dr. H. L. Lyon ;
but of course the whole responsibility for the matter therein contained rests with
me. Those parts dealing with analysis were read over by Mr. S. S. Peck and
Dr. E. S. Norris, to both of whom I am indebted for several suggestions.

To Mr. W. E. E. Potter and Mr. J. H. Wale I am indebted for the originals
of many illustrations, including those of the coloured plates of the Salangore and
the Purple Bamboo Canes, and of the coloured illustrations of insect pests, all of
which are the work of Mr. Potter.

To the Experiment Station Committee of the Hawaiian Sugar Planters'
Association my thanks are due for the loan of the blocks whence are printed Figs.
2-8, 63, 69, 70, 72-76, 82, 83, 105, 126, 188-190; those drawings illustrative
of the anatomy of the cane were prepared under the direction of Dr. N. A. Cobb,
and admittedly form a series remarkable as an exhibit both of technical skill and
artistic merit.

Messrs. Baird & Tatlock have supplied the blocks used in Figs. 237 and 246 ;
Messrs. Peters that of Fig. 238; Messrs. J. & J. Erie that used in Fig. 239; Messrs.
Watson, Laidlaw & Co. those used in Figs. 207 and 208 : Messrs. Pott, Cassels &
Williamson those used in Figs. 204, 206, and 209 ; Messrs. Bullivant & Co. that in
Fig. 93; Messrs. Zeiss that in Fig. 262; Mr.T. L. Patterson that of Fig. 212; Messrs.
Holden & Brooke that of Fig. 270 ; and the Eichardsoii Scale Co. that of Fig. 269.
Mr. J. B. Syme has supplied me with the originals whence Figs. 42, 88 and 98
were prepared.

It will be seen that I have quoted largely from the published works of
Geerligs, of Went, of Kobus, of Harrison, of Eckart, and of Stubbs, to mention
only a few of my sources of information. No work on any subject could pretend
to completeness which failed to avail itself liberally of the results of the leading
investigators.

I have departed from ordinary text-book conventionalism in inserting some
notes in the Appendix, amplifying certain points in the text. Owing to my
distance from my printers I received only a ' paged-out proof,' and it would
have been possible only at some considerable inconvenience to have then made
lengthy alterations in the body of the text.

My thanks are due to Mr. Norman Eodger for the trouble he has taken in
seeing my manuscript through the press.

NOEL DEEEE.
Honolulu,

November, 1910.

IV.

THE LITERATURE OE THE CANE.

The development of the scientific study of the cane only dates back a
generation ; this must be attributed to its decentralized position, and to the
confinement of its growth to districts remote from the older centres of
civilization ; nevertheless, a voluminous and polyglot literature has now
accumulated.

The earliest modernized treatise is that due to Wray, and published under
the title of the Practical Sugar Planter, in 1848; this deals with practice in
the West Indies and the Straits Settlements. Eeynoso's Enmyo sobre el cultivo
de la cana de azucar was published in 1865, and criticises Cuban practice. In
the same year Icery's Recherches t>ur le Jus de la Canne d Sucre, the result of his
Mauritian experiences, appeared. Twenty years later three other notable
French treatises were issued: Delteil's Le Canne d Sucre (1884) gives a
succinct account of the practices in Mauritius and Reunion ; Basset's Guide du
Planteur des Cannes (1889) is of the nature of a general treatise on agriculture
specialized with regard to cane planting; and Boname's Culture de la Canne d Sucre
d Guadeloupe (1888) contains the result of several years' experimental work,
and is remarkable for a very complete detailed balance-sheet of the plant food
material taken up by successive crops of cane.

Ten years later a German text book by Kriiger, Das Zuckerrohr und seine
Kuliur, collated the earlier results of the Java * Proef Stations,' and described
in great detail Javanese practice. The conditions in Louisiana have been
described by Stubbs in Sugar Cane (1897). The Egyptian industry has
been discussed by Tiemann in The Sugar Cane in Egypt (1903); and finally
Sedgwick in Relating to the Sugar Industry in Peru (1904) has given an.
account of the processes there followed.

Of the increasing amount of recorded experimental results appearing within
the past twenty years in the English periodical journals, and especially in the
International Sugar Journal, attention may be directed to the papers of
Harrison, dealing especially with seedling canes, with manures, and with soils,
and to the work which has been done by Watts and Bovell on kindred matter,
and by Howard and Lewton-Brain on the pathology of the cane. In the
English Orient a not unnoteworthy feature is the publication of papers on the
sugar cane by several natives of India.

The United States are represented by records of work done at the Louisiana
Experiment Station, and at that of the Hawaiian Sugar Planters' Association;
and in this connection mention should be made of the work of C. A. Browne,
dealing with manufacture and analysis, and of that in Hawaii concerned with
agriculture and irrigation, initiated by Maxwell, and continued by Blouin and
Eckart. A more recent phase of the Hawaiian work, and one referred to at

v.

CANE SUGAR.

some length in the text, is the development of the 'natural' method of control
of insect pests, under the direction of Koebele, Craw and Perkins.

In the French language the Bulletin de V Association des Chimistes de
Sucrerie, fyc., contains much valuable matter dealing with the sugar cane, to
which H. Pellet has given many important contributions.

It is in Java, however, that the scientific study of the cane has reached
its highest level. During the past twenty years there has come thence a series
of papers, unsurpassed for academic interest and technical value by any similar
series in any industry, either in Europe or America. The work of Geerligs on
•cane sugar manufacture, the pathological and physiological work of Went,
Wakker, Kriiger, van Breda de Haan and Kamerling, the cane breeding
work of Kobus, Bouricius and Moquette, the engineering studies of Delfos,
Bolk, and van Moll, the entomological researches of Zehntner and van Deventer,
and the agricultural enquiries of Kramers and van Lookeren Campagne, make
some knowledge of Dutch essential to the proper appreciation of the cane sugar
industry.

In the pages immediately below is collected an imperfect list of books
and journals dealing directly or indirectly with the cane sugar industry, with
names of publishers where known.

AGRICULTURE.

Porter. Nature and Properties of the Sugar Cane. Smith Elder & Co.,

London, 1843.

Evans. Sugar Planter's Manual. London, 1847.

Wray. The Practical Sugar Planter. Smith, Elder & Co., London, 1848.
Kerr. Treatise on the Cultivation of the Sugar Cane. London, 1851.
Beynoso. Ensayo Sobre el Cultivo de la Cana de Azucar. Bivadenegra,

Madrid, 1865. (Deals with Cuba.)
Delteil. La Canne a Sucre. Chalamel & Co., Paris, 1884. (Deals with Mauritius

and Bourbon.)
Boname. Culture de la Canne a Sucre. Chalamel & Co., Paris, 1888. (Deals

with experimental work at Guadeloupe.)
Semler. Tropische Agrikultur. Wismar, 1888.
Basset. Guide du Planteur des Cannes. Chalamel & Co., Paris, 1889. (Very

detailed general treatise.)

Potter. De cultuur van het suikerriet op Java. Arnheim, 1889.
Kriiger. Das Zuckerrohr und seine Kultur. Schallehn & Wollbriick, Magdeburg,

1899. (Embodies the earlier results of the Java ' Proef Stations.')
Watts. Introductory Manual for Sugar Growers. Longmans, Green & Co.,

London, 1893. (Addressed to small planters of the West Indies.)
Stubbs. Sugar Cane. U.S. Dept. Agric., 1897. (Deals with Louisiana.)
Tiemann. The Sugar Cane in Egypt. Norman Rodger, Altrincham, 1903. (Many

manurial results.)
Sedgwick. The Sugar Industry in Peru. Trujillo, 1904.

vi.

PREFACE.

MANUFACTURE.

Soames. Treatise on the Manufacture of Sugar from the Sugar Cane.

London, 1872.

Walkhoff. Die praktische Eiibenzuckerfabricant. Brunswick, 1872.
Maumene. Traite de la Fabrication du Sucre. Paris, 1878.
Stammer. Der Dampf in der Zuckerfabrik. Eathke, Magdeburg, 1891.
Cambier. Combustion en Sucrerie Paris, 1892.

Beaudet, Pellet et Saillard. Traite de la Fabrication du Sucre. Paris, 1894.
Von Passauer. Die Zuckerfabrikation. Hartleben, Vienna, 1894.
Evangelista. Fabrication del Azucar de Cana. Madrid, 1895.
Horsin-Deon. Traite theorique et pratique de la Fabrication du Sucre. Paris,

1901.

Mclntosh. The Technology of Sugar. Scott, Greenwood & Co., London, 1901.
Foster. Evaporation on the Multiple System. Reed & Sons, Sunderland, 1901.
Hausbrand. Evaporating, Condensing and Cooling Apparatus. Scott, Green-
wood & Co., London, 1903.
Abraham. Die Dampfwirtschaft in der Zuckerfabrik. Schallehn & Wollbriick,

Magdeburg, 1904.
Claassen. Beet Sugar Manufacture. Wiley & Sons, New York, 1907. (London,

Chapman & Hall.)
Ware. Beet Sugar Manufacture and Refining. Wiley & Sons, New York, 1907.

(London, Chapman & Hall.)

WaUis-Tayler. Sugar Machinery. Rider & Sons, London, 1908.
Gredinger. Die Raffination des Zuckers. Hartleben, Leipzig, 1908.
Geerligs. Cane Sugar and its Manufacture. Norman Rodger, Altrincham. 1909.
Jones and Scard. The Manufacture of Cane Sugar. Edward Stanford, London,

1909.
Newlands Bros. Sugar. Spon & Co., London, 1909.

CHEMISTRY AND ANALYSIS.

Sidersky. Traite d' Analyse des Matieres sucrees. Balliere, Paris, 1892.
Wiechmann. Sugar Analysis. Wiley & Sons, New York, 1893. (London,

Chapman & Hall.)

Von Lippmann. Die Chemie der Zuckerarten. Vieweg & Sons, Brunswick, 1895.
Maquenne. Les Sucres et leurs principaux Derives. Gauttier-Villars, Paris, 1900.
Tucker. Manual of Sugar Analysis. Van Nostrand. New York, 1900.
Landholt. The Optical Rotation of Organic Substances. Chemical Publishing

Co., Easton, Pa., 1902.
Friihling and Schulz. Anleitung zur Untersuchung fiir die Zuckerindustrie.

Vieweg & Sons, Brunswick, 1903.
Herrmann. Verlustbestimmung und Betriebeskontrolle der Zuckerfabrication.

Schallehn & Wollbruck, Magdeburg, 1903.

Stolle. Handbuch fur Zuckerfabrikschemiker. Parey, Berlin, 1904.
Eolfe. The Polariscope in the Chemical Laboratory. Macmillan Co., London

and New York, 1904.

vii.

CANE SUGAR.

Morse. Calculations used in Cane Sugar Factories. Wiley & Sons, New York,

1904. (London, Chapman & Hall.)
Tervooren, Methoden van Onderzoek der bij de Java Eietsuikerindustrie

voorkomende Producten. Amsterdam, 1904.
Geerligs. Methods of Chemical Control in Cane Sugar Factories in Java.

Norman Eodger, Altrincham, 1904.

Heriot. Science in Sugar Production. Norman Eodger, Altrincham, 1907.
Spencer. Handbook for Sugar Manufacturers and their Chemists. Wiley &

Sons, New York, 1907. (London, Chapman & Hall.)
Fribourg. Analyse chimique en Sucrerie. Dunod & Pinat, Paris, 1907.
L. Pellet and Metillon. Vade Mecum de Sucrerie. Paris, 1907.
Nikaido. Beet Sugar Making and its Chemical Control. Chemical Publishing

Co., Philadelphia, 1909.
Mittelstadt. Technical Calculations for Sugar Works. Wiley & Sons, New

York, 1910. (London, Chapman & Hall.)

DISEASES AND ENEMIES.

Wakker and Went. De Ziekten van het Suikerriet op Java. Leyden, 1898.
Yan Deventer. De dierlijke Yijanden van het Suikerriet. De Bussy,
Amsterdam, 1907.

FERMENTATION.

Hansen. Practical Studies in Fermentation. E. & F. N. Spon, London, 1896.
Lafar. Technical Mycology. Griffin & Sons, London, 1898, 1902, and 1910.
Eeynolds Green. The Soluble Ferments and Fermentation. University Press,

Cambridge, 1899.

Matthews. Manual of Alcoholic Fermentation. Edward Arnold, London, 1901.
Perrault. Le Ehum. C. Naud, Paris, 1903.

Klocker. Fermentation Organisms. Longmans & Co., London, 1903.
Jorgensen. The Micro-organisms of Fermentation. Macmillan, London and

New York, 1903.

Brandt. Eectification and Distillation of Alcohol. Baird, Philadelphia, 1904.
Herrick. Denatured or Industrial Alcohol. Wiley & Sons, New York, 1907.

(London, Chapman & Hall.)

Mclntosh. Industrial Alcohol. Scott, Greenwood & Co., London, 1907.
Kohl. Die Hefepilze. Quelle & Myers, Leipzig, 1908.

GENERAL AGRICULTURE.

Hall. The Soil. John Murray, London, 1908.
Hall. Fertilizers. John Murray, London, 1909.
Hilgard. Soils. The Macmillan Co., New York and London, 1907.
The Eural Science Series; various dates and authors. The Macmillan Co., New
York and London.

viii.

PREFACE.

STEAM, &c.

Poole. Calorific Value of Fuels. Wiley & Sons, New York, 1904. (London,
Chapman & Hall.)

Pullen. Experimental Engineering. Scientific Publifehing Co., Manchester, 1904.
Perry. The Steam Engine. Macmillaii & Co., London and New York, 1907.

Thurstou. A Manual of the Steam Engine. Wiley & Sons, New York, 1907.
(London, Chapman & Hall.)

Carpenter. Experimental Engineering. Wiley & Sons, New York, 1909.
(London, Chapman & Hall.)

Juptner. Heat, Energy and Euel. Macraw Publishing Co., New York, 1909.

I feel that I am open to criticism in pretending to recommend books on
subjects so indirectly connected with sugar as those included under the last
three captions, especially since in these branches of technology there are so
many to choose from. I merely mention those which I have used myself to
obtain a better understanding of certain phases of the sugar industry.

I know of no more suitable agricultural library for the sugar planter
generally than the books included in the " Rural Science Series," published by
Macmillan. Each volume is a monograph on some part of agriculture, written
by well-known United States experts, which, while not sacrificing accuracy to
popularity, treats its subject in a way which will appeal to the non-technically
trained planter.

JOURNALS DEVOTED TO THE SUGAR INDUSTRY.

The Sugar Cane. Manchester, 1869-1898.

The International Sugar Journal. Altrincham, Manchester, 1899-

The Louisiana Planter. New Orleans, 1887-

The Hawaiian Planters' Monthly. 1882-1909.

The Sugar Journal. Mackay. 1882-1906.

Journal des Fabricants de Sucre. Paris, 1866-

Bulletin de 1'Association des Chimistes de Sucrerie. Paris, 1882-

Sucrerie Indigene et Coloniale. Paris, 1886-

Archief voor de Java Suikerindustrie. Soerabaia, 1893-

Centralblatt fur die Zuckerindustrie. Magdeburg, 1892-

JDie Deutsche Zuckerindustrie. Berlin, 1876-

La Sucrerie Beige. Brussels, 1872-

Osterreichisch-Ungarische Zeitschrift fiir Zuckerindustrie. Vienna, 1873-

Zeitschrift liir Zuckerindustrie in Bohmen. Prague, 1872-

Zeitschrift des Vereins der Deutschen Zuckerindustrie. Berlin.

The Australian Sugar Journal. Brisbane, 1909-

The American Sugar Industry and Beet Sugar Gazette. Chicago, 1899-

The Sugar Beet, Philadelphia.

ix.

CANE SUGAR.

EXPERIMENT STATIONS DEVOTED WHOLLY OR IN PART TO THE
CANE SUGAR INDUSTRY.

British Guiana. — Botanical Gardens. Experiments on Sugar Cane (and other
tropical plants) conducted chiefly by J. B. Harrison ; results published mainly
as reports to the Governor, and often quoted in extenso in the Sugar Cane
and International Sugar Journal.

British West Indies. — Experimental work conducted under the direction of the
Imperial Department of Agriculture in Barbados, Antigua, St. Kitts. The
experimental work in Trinidad, and at the Sugar Experiment Station in
Jamaica under the direction of H. H. Cousins, seems less closely associated
with the Department. The present Commissioner is Francis Watts, the first
having been Sir Daniel Morris ; connected with the Department is a large
staff of scientists ; results are published in The West Indian Bulletin as
separates.

Cuba. — Estacion Centrale Agronomique. Director, E. G. Oses ; previous directors
have been F. S. Earle and J. T. Crawley. Eesults published as Bulletins.

Porto Rico. — Agricultural Experiment Station under the U.S. Dept. Agric.

D. W. May, special agent in charge. Eesults published as Bulletins.

Louisiana. — Experiment Station at Audubon Park, in connection with State
University, which also maintains a ' Sugar School.' Director : H. P. Agee ;
previous directors have been W. Stubbs and W. E. Dodson. Eesults published
as Bulletins.

Hawaii. — Experiment Station of the Hawaiian Sugar Planters' Association.
Director: C. F. Eckart; previous directors have been W. Maxwell and

E. E. Blouin. Eesults published as Bulletins.

Argentina. — Sugar Experiment Station in Tucuman. Director E. E. Blouin.

Peru. — Sugar Experiment Station. Director : Caesar Broggi ; previous directors
have been T. Sedgwick and F. Zerban. Eesults published as Bulletins.

Mauritius. — Station Agronomique. Director : P. Boname. Eesults published as
Bulletins.

Queensland. — Experiment Station at Mackay. Director: H. Easterby; previous
director was W. Maxwell.

India. — Experimental Sugar Farm at Samalkota, Madras. C. A. Barber, Govern-
ment botanist.

West Java. — Proef Station. Director : J. J. Hazewinkel ; previous directors have
been H. C. Prinsen Geerligs and F. Went.

East Java. — Proef Station. Director, J. E. van der Stok ; previous directors
have been G. Kramers, J. K. Wakker, and J. D. Kobus.

Mid. Java. — Proef Station. Director : W. van Deventer ; previous directors have
been F. Soltwedel and F. Benecke. Eesults published as separate prints,
and also often to be found in the Archief voor die Java Suiker Industrie.

NOEL DEERR.

x.

TABLE OF CONTENTS.

CHAPTER I. PAGE

The Cane 1

CHAPTER II.
The Composition of the Cane 13

CHAPTER III.
Eange and Climate 18

CHAPTER IV.
Varieties of the Cane 23

CHAPTER V.
Sugar Cane Soils 46

CHAPTER VI.
The Manuring of the Cane .... 55

CHAPTER VII.
The Irrigation of the Cane 91

CHAPTER VIII.
The 'Husbandry of the Cane 102

CHAPTER IX.
The Pests and Diseases of the Cane 127

CHAPTER X.
The Harvesting of the Cane 159

CHAPTER XI.
The Extraction of Juice "by Mills 170

CHAPTER XII.
The Diffusion Process 226

CHAPTER XIII.
The Clarification and Defecation of the Juice 241

CHAPTER XIV.
The Carbonation Process 262

CHAPTER XV.
The Filtration of the Juice 273

xi.

TABLE OF CONTENTS.

CHAPTER XVI. . PAGE
The Evaporation of the Juice to Syrup 282

CHAPTER XVII.
The Concentration of the Syrup to Massecuite 339

CHAPTER XVIII.
The Separation of the Crystals 371

CHAPTER XIX.
Molasses •• 388

CHAPTER XX.
Megass as Fuel 404

CHAPTER XXI.
The Polariscope as applied to Sugar Analysis •• •• 42?

CHAPTER XXII.
The Optical Assay of Sugars 44?

CHAPTER XXIII.
The Determination of Reducing Sugars 459

CHAPTER XXIV.
The Assay of Sugar House Products 471

CHAPTER XXV.
The Control of the Factory 492

CHAPTER XXVI.
Fermentation with Special Reference to the Sugar House 615

APPENDIX.

Tables.
Table of Properties of Saturated Steam. (After Peabody) .......... 547

Table of Correspondence between Brix and Specific Gravity OQ ........ 555

o/\O/"1

Table of Correspondence between Brix and Specific Gravity — 7op~ ...... ^58

Table of Temperature Corrections for Brix Hydrometer graduated at 17'5°C .... 561

Table of Temperature Corrections for Brix Hydrometer graduated at 27'5°C . . . . 562

Table of Dry Substance from Refractive Index at 28°C. (After H. C. Prinsen

Geerligs) .; ........................... . 563

Table of Corrections for the Temperature .................... 568

Table of the Density of Water ........................ 568

xii.

TABLE OF CONTENTS.

PAGE

Table of the Elevation of the Boiling Point of Sugar Solutions (Claassen) .... 569

Table showing the Expansion of Sugar Solutions (Grerlach) 570

Table giving the Percentages by Weight, per cent., on Original Juice evaporated

between different Degrees Brix or Beaume 571

Table of Equivalents of Copper and Dextrose for Allihn's Method 572

Table of Sodium Carbonate at 82-50°F (Schiff) 576

Table of Caustic Soda at 82-5°F (Geerligs) 577

Table showing the Solubility of Sugar in Water (Herzfeld) 578

Table showing the Solubility of Lime in Sugar Solutions 578

Table showing the Solubility of Salts in Sugar Solutions (Jacobsthal) 578

Additional Notes relating to Certain Portions of the Text 579

INDEX.

Subject Matter 581

Names .. 588

xm.

ERRATA.

Page 72, Line 6 from bottom. — For Eriodendnon read Eriodendron.

Page 84, last line. — For deeringannm read deeringianum.

Page 88, Line 14. — For land read hand.

Page 91, Line 17. — Between in and many insert so.

Page 93, Line 11 from bottom. — Delete and evaporation.

Page 95, Line 1. — For Eegnoso read Reynoso.

Page 122, Line 13 from bottom. — For creditable read credible.

Page 136, Line 12. — For Cakididae read Chakidoidta.

Page 163, Line 21 from bottom.— For fTallis Taylor read Wallis-Taykr.

Page 266, Line 16.— For 7\ T0 read 7\ - T0.

Page 291, last two lines. — The sentence and the vertical baffles d give an up and
down circulation to the juice should be deleted, as the lines marked d in the
illustration are not baffles but represent the webs of one of the feet which
carry the evaporator.

XIV.

LIST OF PLATES.

Referred to To Face

in Text as Page

Frontispiece (Figs. 45-56 $ 58-59 J

I. Bourbon Cane (Fig. 9) .... 16

II. Eose Bamboo Cane (Fig. 10) .. . . 32

III. Purp^ Bamboo Cane. . .. (Fig. 11) .. .. 48

IV. Striped Bamboo Cane (Fig. 12) .. .. 64

V. White Tanna Cane (Fig. 13) . . . . 80

VI. Striped Tanna Cane (Fig. 14J .... 96

VII. Steam Plough (Fig. 31) .. .. 104

VIII. Black Tanna Cane (Fig. 15 J .. .. 128

IX. Salangore Cane (Fig. 16 J .. .. 144

X. Cane Sleds (Fig. 86) .. . . 160

Wheeler-Wilson Loader (Fig. 87) .. . . 160

XL Fixed Derrick for transferring Cane (Fig. 89) .. . . 161

XII. Ox Team and Load (Fig. 90) .. . . 168

Eoad Engine for transporting Cane (Fig. 91) . . . . 168

A Typical Cane Train (Fig. 92) .. .. 168

XIII. Cane Wagons (Fig. 96) .. .. 169

XIV. Cane Hoppers (Fig. 97) .. .. 176

XV. Cane Unloader (Fig. 99) . . . . 177

Cane Unloader (Fig. 101) .. .. 177

XVI. Port Mackay Cane (Fig. 17) .. .. 256

XVII. Iscambine Cane (Fig. 18) . . . . 337

XVIII. Electric-Driven Spindle of Centrifugal (Fig. 201) .. .. 376

XIX. Water-Driven Centrifugal (Fig. 209) .. .. 377

XX. Huillard Drier (Fig. 225) .. .. 416

XXI. Yeasts , . (Fig. 216) .. .. 520

XXII. Yeasts (Fig. 217) .. . . 521

xv.

CANE STJG-AB.

CHAPTER I.

THE CANE.

The sugar cane is a grass belonging (following Engler's classification) to
the cohort Glumiflorce, natural order Graminea, tribe Andropigonece, genus
Saccharum.

The genus Saccharum is divided by Hackel1 into four sub- genera, (a)
Eusaccharum, (i) Sclerostycha, (c~) Eriochrysis, (d") Leptosaccharum. A detailed
account of these sub-genera will be found in Kriiger's Das Zudcerrohr? The
cultivated species Saccharum officinarum, belongs to the first sub-genus, and is
itself divided by Hackel into three groups.

(a) genuinum. Stein pale green to yellow, darker yellow near the
ground. Leaf, grass- green, underside sea-green.

(b) violaceum. Stem, leaf sheath, lower side of leaves, panicle, violet.

(c) litteratum. Stem dirty green or yellow, marked with dark red stripes
at equal intervals.

In the group genuinum is to be included the S. sinense, or Chinese cane ;
the group litteratum would include all ribbon canes, but as these sport fre-
quently from self-coloured canes and vice versa, the distinction must not be
pushed too far. Cordemoy3 divided the canes known in the island of Bourbon
into S. officinarum, S. violaceum, and S. sinense (the Chinese cane) ; elsewhere
in the literature of the cane the purple transparent or Black Cheribon cane is
sometimes found incorrectly called S. violaceum. The true S. violaceum occurs
indigenously in the Hawaiian Islands, and is known under the native name
of Manulele.

The complete cane may be divided into the roots, the root-stock, the
stem, the leaf, including leaf-sheath and blade, and the inflorescence.

1

CANE SUGAK.

Stalk.— The stalk of the cane is roughly cylindrical, and varies widely
in size, not only with the variety, but also with the conditions of growth ; the
diameter varies from a minimum of £ inch to a maximum of 3 inches. The
smallest diameter is found in varieties seldom cultivated, as, for example,
the Branchu, and among the reed-like canes grown by the ryots of British
India, and in some parts called Nanal canes.4 The greatest is found in the
Elephant canes, while the Striped and Black Tanna canes are also of
comparatively large girth. The Cheribon canes (cp. Chapter IF.) are types
of the more slender cultivated canes, while the Bourbon may be considered of
average diameter. The length of the stalk in the best cultivated varieties
reaches to as much as 20 feet ; in others, such as the Bois-rouge and Branchu,
the maximum height is very much less. In its early stages of growth the
cane is erect, and in some varieties, e.g., Yellow Caledonia or White Tanna,
and D. 74, it remains so ; in others, such as the Otaheite, it becomes markedly
recumbent.

FIG. 1.

The stalk is made up of a series of joints, or intern odes, /, Fig. 1,
separated from each other by the nodes, e ; generally the internodes grow
in a continuous line, but occasionally they are ' staggered,' each internode
growing at an angle with the next one. The diameter at the node is generally
a little larger than at the internode, but in some varieties the internode is
notably swollen. The length of the internode may reach to as much as
10 inches, but in well grown Otaheite cane this is generally 4 to 6 inches;
the Tanna canes are distinctly short-jointed in proportion to girth, while the
B. 147 cane may be taken as an example of a long- jointed variety. The
length of joint is influenced largely by conditions of growth ; thus it becomes
very much reduced when affected by drought or by the cold weather, or when
the leaf of the cane has been attacked by disease. The number of internodes
may be as many as eighty, or as few as twenty. At each node, and alternately,
at opposite sides, is an embryo cane, known as the eye, b, Fig. 1 • it is the
size of a pea or larger, and may be triangular, oval, or almost hemispherical ;
in some varieties, as the Branchu, the eye is swollen and prominent. The eye
is covered with a resinous substance and with several layers of bud-scales.

THE CANE.

Immediately above each joint appears a ring of semi-opaque whitish spots;
this is the zone of adventitious roots; each spot is an embryonic root. In some
varieties the roots on the portion above ground under normal conditions develop
freely, and form a kind of aerial root ; under other conditions this sprouting of
the roots is one of the symptoms of the disease known as 'Sereh'; with canes
of a recumbent habit sprouting is frequent, and leads to a general weakening
of the plant.

The outer surface of the stem is known as the rind ; it may be green,
yellow, red, purple, white or striped, or blotched in a combination of these
colours.

The Root. — The 'root' or root-stock of the cane is merely a prolonga-
tion of the stalk beneath the surface of the ground attached to the mother cane
in plant cane, or to the mother stalk in ratoon cane. The true roots of the
cane spring from the nodes of the stem ; they are fibrous, lateral, and very
delicate; they ramify in all directions, generally extending from 18 inches
to 3 feet from the stem. Stubbs5 says that the roots do not penetrate veiy
deeply, but Ling Roth6 mentions roots extending as far downwards as 4£ feet,
and Liversedge6 states that he has seen roots as far down as 8 or 10 feet. The
depth to which roots penetrate, however, depends largely on the nature of the
soil ; they extend furthest in light porous soils. In seasons of drought the
roots extend downwards following the water level; on the other hand,
in fields with a sour ill-drained sub-soil, the roots, after penetrating down wards,
turn back on themselves to the upper surface soil. The cane has no tap root,
and its roots have comparatively little hold on the soil.

The Leaf. — The leaves of the cane are alternate and opposite, one at
each joint ; actually, the leaf consists of two parts, the leaf sheath and the
leaf blade. The leaf sheath springs from the node. It completely embraces,
at its base, the stalk, and gradually recedes from it ; the sheath is colourless
or pale green, and about 12 inches long at maturity. The blade is from
3 to 4 feet long, and 2 to 3 inches wide ; in colour the leaves are varying
shades of green ; in some varieties, as in the Cavengerie, variegated or entirely
white leaves are often developed. Some Pacific Island canes fS. violaceum)
have purple leaves. The leaves taper towards the top, and are delicately
serrated along the margin ; in many varieties setae or hairs abound at the base
of the leaf, capable of forming painful punctures iu the skin; the leaf is
traversed longitudinally by a number of veins. The midrib is generally white,
but sometimes reddish or purple, and is formed with a channel-like depression
in its upper surface. The leaves at maturity fall away from the stalk, and in
some varieties separate themselves entirely.

CANE SUGAR.

The Flower. — The inflorescence of the cane is a panicle of soft silky
spikelets, borne on the end of an elongated peduncle, called the arrow, arising
from the terminal vegetative
point of the cane.

I | | ; j | ; ; i ; . ; . / :

In Fig. 2 is given a drawing, M I M M I /

enlarged 30 diameters, of a single
flower of Lahaina cane. At 1 is
the ovary, the growth of which
produces the seed ; it is ovoid and
sessile; from the ovary proceed
two styles of a reddish colour,
bearing the plumose stigmas, 2.
At 3 are the three anthers which
produce the pollen, that serves to
fertilize the stigmas ; at 4 are the
two lodicules, the function of
which is, by swelling at the
proper time, to open the cane
blossom; at 5 is the innermost
palet of the cane flower, and at 7,
6, and 8 the remaining palet and
the glumes ; at 9 are the bristles
that surround the base of the
flower. It is only exceptionally
that the cane forms fertile seed.
Some varieties never flower, and
others do so only in the tropics.
The age at which the cane
flowers varies from eight to
fifteen months, and is dependent
on variety and climate and also on
time of planting. Flowering
takes place at certain definite
times of the year, varying in the
different cane-growing regions,
and if the cane is not sufficiently
mature at the flowering time in
its first year, no formation of
flowers occurs until the second
year. In this way a delay of a
few weeks in planting will retard
flowering for twelve months. FIG. 2.

THE CANE.

Fin. 3.

Structure of the Stalk. —

On cutting across a cane it will be seen
2 that it consists roughly of three parts,
a hard outer rind, and a mass of softer
tissue in the interior, interspersed with
fibres, the latter being more frequent
about the periphery of the stalk. The
rind is made up of a thick epidermis
with a strong outer cuticle, impervious
to water, and a layer of thick-walled
cells ; the function of the cuticle is to
prevent evaporation of water from the
stem of the cane, and to protect the
softer interior parts from mechanical
injuries ; the layer of thick-walled cells
gives rigidity and strength to the stem.
These thick-walled cells gradually pass
into the thin-walled cells of the ground
tissue, or parenchyma, which serve to
store up the sweet juice of the cane.
The fibres are known as the fibro-
vascular bundles ; they consist of the
wood vessels, sieve tubes and com-
panion cells, surrounded by thick-
walled fibres.

A cross section of the cane, as
seen under the low power of a
microscope, is shown in Fig. 3.

1. The epidermis, with thick
cuticularized walls.

2. Thick- walled ground tissue of
the rind.

3. A small vascular bundle ; these
are : found mainly in the outer portion of
the stem, and their function is chiefly
mechanical.

4. An intermediate bundle with*
two vessels and a few thin-walled1,
phloem elements.

5. Thick-walled fibres ; these are-
the mechanical elements of the bundles,
and are more numerous in the bundles,
towards the outside.

CANE SUGAR.

6. Thin-walled cells of the ground tissue or parenchyma.

7. A large vascular bundle found toward the centre of the stem.

In Fig. 4 is shown more highly magnified a bundle corresponding to 7
in Fig. 8.

1 . A vessel with unbordered pits.

2. An annular vessel.

3. A sieve tube with the companion cells, making up the phloem.

4. An intercellular air space.

5 and 7. Thick- walled mechanical elements, the fibres, or sclerenchyma
forming a sheath around the bundle.

6. Ground tissue or parenchyma.

When seen in longitudinal section the cells of the parenchyma are found
to be rather longer than wide.

6

THE CANE.

^

*$

7

CANE SUGAR.

The sieve tubes seen in longitudinal section are observed to be very
elongated cells, with perforated partition walls at intervals in their length J
the vessels are continuous throughout their length.

In the internodes the fibro- vascular bundles run parallel, but at the nodes
they freely branch and communicate with each other, and pass on into the leaf
and into the next internode, passing down right into the roots of the cane.

The physiological function of the nbro-vascular bundles, apart from their
mechanical action, is to transmit water, charged with food material, from the
root to the leaf of the cane ; this water passes upwards by way of the vessels
to the leaf, where it is elaborated, and then passes downwards through the sieve
tubes to be either stored in the parenchymatous cells or to be used up in the
economy of the growing plant ; the function of the companion cells is not
thoroughly understood.

Structure of the Leaf. — In Fig. 5 is shown a cross section of a
leaf of the cane, to which we add Dr. Cobb's explanation of the plate.

" Cross-section of a portion of healthy cane leaf taken half way between the
midrib and the margin near the middle of a full-grown but not yet fully lignified
leaf. The upper side of the figure, 1 to 18, represents the top surface of the leaf.
The fructifications of the leaf- splitting disease occur in positions corresponding to
3, 4, 5. The green chlorophyll bodies are here shown black. It is owing to the
destruction of these green bodies in portions of the leaf such as here represented,
namely, between the largest vascular bundles, that the leaf takes on a striped
appearance. The part of the leaf to be examined was fixed with the vapour of osmic
acid while still attached to the cane plant. The fixed portion was differentiated into
glycerine and cut in that condition. The drawing was projected from a photograph
and sketched. The details were drawn in from the examination of sections either
unstained or stained with aniline safranin. The section shows five fibro- vascular
bundles, the largest of which is indicated at 6 to 11, the smallest at 23 and 32.
Portions of the other two, which are intermediate in size, are shown at 19 and 36.
None of these bundles are of the largest size. Bundles fully twice the size of the
larger here shown occur in the cane leaf, and such large bundles are characterized
by the possession of annular vessels, none of which occur in these smaller bundles.
Throughout the illustration structures of the same class are indicated by a similarity
in the draughtsmanship, thus the woody cells indicated at 9 are repeated in various
parts of the figure, more particularly next to the epidermis of the lower surface.

" 1, a set of so-called motor cells, in this instance composed of two cells, whose
nuclei are pointed out at 2 and 3 ; 4, an internal cell of somewhat similar character
to that pointed out at 1,2, and 3 ; 5, another cell of the same class cut in such a
way that the nucleus has been removed ; 6, sclerenchyinatous cells imparting
strength to the fibro-vascular bundle ; 7, one of the layer of parenchymatous cells
rich in chloroplasts and immediately surrounding each fibro-vascular bundle ; 8, one
of the stomata, found more rarely on the upper than on the lower surface of the
leaf; 9, woody cells imparting strength to the cane leaf, and occurring on the dorsal
and ventral side of each fibro-vascular bundle ; 10, one of the cells constituting the
sheath of the vascular bundle,— these cells contain chloroplasts arranged along the
outsides of their walls; 11, tracheal vessel; 12, one of the cells of the upper
epidermis; 13, nucleus of a similar cell; 14, upper cuticle at its usual thickness;
15, a two-celled hair on the surface of the leaf ; 16, thinner cuticle of the upper
surface of the leaf as it occurs over the so-called motor cells; 17-18, group of
so-called motor cells, consisting in this case of four cells ; 19, fibro-vascular bundle

> THE CANE.

of intermediate size ; 20, chloroplast in one of the cells of the lower epidermis ;
21, one of the stomatic openings that are abundant on the lower surface of the leaf;
this one is closed, — an open one may be seen at 25-26 ; 22, accessory (?) cell of the
stomatic opening; 23, one of the smallest fibre-vascular bundles ; 24, one of a group
of cells very rich in protoplasm which extends between the vascular bundles, — the
nearer these cells are to the lower epidermis the denser their protoplasmic contents ;
25-26, protoplasts in the guard cells of the stomatic opening ; 27, one of the sieve
tubes,— among these sieve tubes may be seen the smaller companion cells and their
protoplasts ; 28, extra chlorophyll-bearing cells outside the single layer surrounding
the vascular bundle; 29, lip of one of the stomatic guard cells; 30, cell rich in
protoplasm, of the same class as 24 ; 31, nucleus of one of the companion (?) guard
cells ; 32, fibro-vascular bundle of small size ; 33, apparently a locule in the
thickened portion of the wall of the stomatic guard cell ; 34, entrance between the
guard cells of the stomatic opening ; 35, cuticle of the lower surface of the leaf ;
36, fibro-vascular bundle of intermediate size ; 37, 37, 37, air chambers immediately
above the stomatic openings. Throughout the illustration the nuclei are shown
grey, and the nucleoli black. The tissue represented at 24 and 30 is probably
primary leaf-tissue, from which during the growth of the leaf the various tissues
represented have been differentiated."

Function Of the I^eaf.— In a sense the leaf may be termed the
manufactory of the plant ; under the influence of the chlorophyll and in direct
sunlight starch is formed from water and carbon dioxide ; other transforma-
tions occur, and the material passes down to be stored in the stem as sugar.
The stomata serve for the respiration of the carbon dioxide, and for the
secretion of the waste products of the plant; the fibre, or sclerenchyma, as
in the stem, gives rigidity to the leaf. The leaf in its early stages is rolled
up, and is opened by the expansion of the motor cells ; in dry weather these
cells contract and cause the leaf to roll up, thus exposing a less surface for
evaporation.

Structure of the Root. — In Fig. 6 is shown to a scale of 1^
the end of one of the roots growing from the zone of adventitious roots

in that part of the stem of the cane below
ground. Towards the end of the root are seen
^™ •' ^N numerous very fine hairs, and at the extreme

end is seen the root cap. In Figs. 7 and 8

Ji ^^^^V "iii^H^ are Sivea longitudinal and cross-sectional views
of the root, the longitudinal view being taken
through the apical point ; re is the root cap, m is
FIG. 6- the layer of meristematic tissue, rh a root hair

formed from the piliferous layer on the extreme outer layer of the root ; cor
is the cortex, st the central cylinder, v a developing wood vessel, and x a
larger wood vessel.

The root cap on the exterior consists of dead cells, and is continually
being renewed from the interior by the layer of meristematic tissue from
which also arise by a continual process of cell sub-division all the other
tissues of the root.

CANE SUGAR.

Function of the Root.— The functions of the root are two-fold ;
the root hairs closely envelop particles of soil, thereby maintaining the hold of
the plant on the soil, and, secondly, the root hairs absorb water and plant food
from the soil and transmit it to the other parts of the growing plant.

Physiology of the Cane.— The physiology of the cane has been
studied chiefly by Went7 who concluded

cor

cor

re

FIG. 7.

1. That cane sugar is the chief product of assimilation in the cane leaves,
dextrose and levulose only being formed by inversion; maltose was not
identified ; the proportion of sucrose, dextrose, and levulose in the juice of
the leaves is as 4 : 2 : 1.

2. The sugar of the leaves is carried during the night in the form of
invert sugar to the stem and deposited round the cellular vessels as starch.

3. The parenchyma of the leaves, and above all of the central rib, is very
rich in sugar and tannin, while the cellular vessels contain less sugar and
tannin and more albumenoids.

10

THE CANE.

4. Generally those parts of the plant undergoing cellular division contain
much starch and albumen and little sugar ; where cellular division is restricted
the reverse obtains.

In the life history of the stalk the following phases are distinguished : —

1. In very young parts of the stalk only starch or albumen are present,
which are consumed little by little in the formation of cellulose.

2. In young, rapidly-growing parts of the stalk, the cane sugar brought
down by the leaf is inverted, and whereas in the leaf the proportions of
sucrose, dextrose, and levulose were as 4 : 2 : 1, in the young joints the proportions

X75

FIG. 8.

are *8 : 1 : 1. A. part of the invert sugar is used up in the formation of fibre,
a part unites with the amides to form albumen, and a part is deposited as
starch. In consequence of the inversion, the osmotic pressure is raised and
this tends to favour the absorption of plant food.

3. In older joints the sucrose formed in the leaf remains unchanged
when it reaches the joint and the reducing sugars are used up, partly in
respiration, or, perhaps, are partly by a reverted enzyme action converted into
sucrose ; of the reducing sugars that remain, the dextrose is generally in
excess.

11

CANE SUGAR.

4. When the stalks are developed, the accumulated invert sugar is con-
verted to sucrose ; of the invert sugar remaining the dextrose is generally in
excess.

5. When the stalks are ripe the leaves die and the accumulation of sugar
gradually ceases; the remainder of the invert sugar is changed to sucrose,
eventually only traces of invert sugar remaining.

6. When the stalks are over-ripe the sucrose is converted into invert
sugar, but this change does not prevent the younger parts of the cane
accumulating sugar.

The roots of the cane only contain sugar when very young ; as the age of
the cane increases the sugar is converted into starch and cellulose.

Starch has been recognised in cane leaves cut in the day time.

REFERENCES IN CHAPTER I.

1. The True Grasses, p. 15.

2. Das Zuckerrohr, pp. 5-24.

3. Quoted by Delteil in Le Canne a Sucre, p. 14.

4. /. S. J., 45.

5. Stubbs' Sugar Cane, p. 13.

6. Quoted by Lock and Newlands in Sugar.

7. Arch. IV., 525.

The blocks whence Figs. 2-6 were printed have been lent by the Experiment
Station of the Hawaiian Sugar Planters' Association. They have previously
appeared in the Bulletins issued by the H.S.P.A. Experiment Station; the original
drawings were made by Mr. E. M. Grosse, Mr. W. E. Chambers, and Miss Frieda
Cobb, under the direction of Dr. N. A. Cobb.

12

CHAPTER II.

THE COMPOSITION OF THE CANE.

The cane is not by any means of even approximately uniform composition,
but differs with variety and conditions of growth. The limits of composition
of single canes may be estimated as : — Water, 69 per cent, to 75 per cent. ;
Saccharose, 7 per cent, to 20 per cent. ; reducing sugars, 0 to 2 per cent. ;
fibre, 8 per cent, to 16 per cent. ; ash, -3 per cent, to *8 per cent. ; organic non-
sugar, -5 per cent, to 1 per cent.*

The percentage of sugar in the cane, though to some extent dependent on
variety, is by no means entirely so ; conditions of soil and climate have a great
influence. In Demerara, where up to 1900 practically the whole crop was
Bourbon cane, canes grown on virgin soil gave heavy crops, with generally less
than 11 per cent, of sugar, the sugar percentage of canes grown on older land
often rising to 14 per cent, or more. As an instance of variety affecting
composition the difference between Lahaina and Yellow Caledonia cane grown
under the same conditions in Hawaii may be cited, the former almost invariably
affording a sweeter purer juice, and also containing less fibre ; amongst other
canes that by comparison with the Lahaina ( Bourbon, Otaheite, &c.) afford a
poor juice may be cited the Elephant cane, the Cavengerie (Po-a-ole, Altamattie,
Giant Claret, &c.) and the Salangore.

When seedling canes were first grown, evidence was obtained on the
small scale that high sugar content was an inherent property of certain
varieties, of which D. 74 may be quoted ; on the estate scale, however, the
results were very disappointing. Latterly, however, much evidence has
accumulated that the cane B. 208 is one of high saccharine content and
similar results have been obtained in Java ; in addition it has been shown by
Kobus that it is possible to obtain a strain of canes of high sugar content by a
process of chemical selection.

* Mr. Prinsen Geerligs on p. 94 of Cane Sugar and its Manufacture gives the following
limits : Sucrose, 11 per cent, to 16 per cent. ; reducing sugar, -4 per cent, to 1*5 per cent. ; Fibre,
10 per cent, to 15 per cent. ; Ash, '5 per cent, to 1 per cent, and elsewhere protests against
exaggerated statements of the sucrose content of the cane. The crop averages for canes raised
in the arid areas of the Hawaiian Islands under irrigation often reach 16 per. cent, and for
single weeks may be as much as 18 per cent., single canes even containing 20 per cent. On the
other hand the writer has met with large areas of year old plant cane in Demerara containing
only 7 per cent, and with reducing sugars over 2 per cent.

13

CANE SUGAR.

Distribution of Sugar in the Cane.— The cane is not of
uniform composition throughout its length, and it is this property that makes it
a matter of such difficulty to obtain representative analyses of large quantities
of cane. The annexed table of analyses by Boname2 illustrates this point.

A. Plant cane, imperfectly ripe and still in full vegetation.

B. Second ratoons, 11 months old.

C. Fourth ratoons in vegetation.

D. First ratoons, 11 months old.

E. Creole cane, the stalk 1 metre long and 10 cm. in circumference.

F. Plant cane, very ripe, 14 months old.

Degree Sugar Glucose

BeaumS. Per cent. Per cent.

A. Lower part ........... 9-05 .. 13'74 .. 1-78

Middle „ ............ 95 .. 14-11 .. 2-44

Upper „ .......... 8-2 .. 8'85 .. 4-11

White top ............ 7-5 . . 4-01 . . 6'57

B. Lower third ........... — ... 16'20 . . -94

Middle „ ............ — .- 15'40 .. 1-59

Upper „ .......... — -. 13'60 .. 1-75

C. White top ............ — .. 9-07 .. 1'95

Upper part .......... — . . 16'52 . . -78

Lower „ ............ — .. 19-44 .. '37

D. Lowest fourth .......... ll'l .. 20'73 .. -37

Lower middle fourth ........ 1M .. 20-41 .. -37

Upper „ „ ...... 10-7 .. 19-44 . -65

Upper fourth .......... 10-4 . . 17'82 . . '52

White top ............ 9-2 .. 14-90 .. -71

E. Lower third ........... — . . 8*74 . . 3-56

Middle , ........... — .. 1'24 .. 4-38

Upper ,, ............ — .. 4-62 .. 4'56

F. Lowest fourth ...... • .. .. 12'3 .. 22-68 .. -51

Lower middle fourth ........ 12'3 .. 22-68 .. -52

Upper ,, „ ..... 12-3 .. 22-68 .. -52

Upper fourth .......... 12-0 .. 22-03 .. '53

White top .......... 10-0 . . 16-84 . '70

The variation in composition of the juice in the nodes and internodes is
given by Boname.

( Sugar ............ 13-34 .. 12-74 .. 16-73

3 I Glucose .......... -29 .. -28 .. -31

Sugar . 16-51 . 16'80 . 19-72

Internodes .. __ .60 . . .84 . . -48

Stubbs2 gives the following as the result of analyses of twenty stalks of
purple cane : —

Degree Solids

Brix. Sugar. Glucose, not sugar. Fibre.

Nodes ...... 15-94 .. 12-6 .. -13 .. 3-21 .. 16'5

Internodes ____ 17'40 .. 15!5 .. '94 .. -96 .. 8-00

The great variation in composition of juice at nodes and internodes is well
shown in the tables quoted above and an explanation given of the decreased sugar
content of second mill juice compared with first mill juice, the more woody nodes
only yielding their juice on a more powerful crushing.

14

THE COMPOSITION OF THE CANE.

The Reducing Sugars of the Cane. — The reducing sugars of
the cane consist almost wholly of dextrose and levulose. Wiley, working on
sub-tropical cane, found both these sugars, but Winter, in Java, with tropical
cane, found only dextrose. Geerligs,4 however, showed that in Java dextrose
and levulose are both formed, but that the latter is used up more rapidly in
the plant's economy, and tends to disappear, and this observation has also been
made by C. A. Browne,6 in Louisiana. Finally, as has been shown by Wiley,4
the reducing sugars may be entirely absent in perfectly ripe cane. In over-ripe
cane they again appear, due to the inversion of the saccharose.

The Non- Sugars of the Cane. — The following bodies have been
identified in the cane ; a doubtful identification is shown by italics : —

Inorganic bases : potash, soda, lime, magnesia, iron, alumina, manganese
oxide, titanium oxide.

Inorganic acids : sulphuric, phosphoric, silica.

Organic Acids : malic, succinic, oxalic, glycolic, acetic (in damaged cane),
citric, tartaric, aconitic.

Nitrogenous bodies : albumen, nucleins, albumoses, peptones, amines,
amido acids, xanthine bases, lecithins.

Non-nitrogenous bodies : Fat, wax, chlorophyll, anthocyan, pectin, xylan,
araban, gum, cellulose, lignin.

Composition of different Parts of the Cane.— According to
C. A. Browne6 the average composition of Louisiana cane is as shown in the
following table: —

]
Water ,.

Leaves.
Per cent.
74-38

Stalks.
Per cent.
. . 74-96 . .

Roots.
Per cent.
68-79 . .

Seeds.
Per cent.
11-03

Ash

2-23

6-64 . .

1-87 ..

5-22

Fat and Wax .. ..

0-69

0-38 ..

0-54 . .

2-01

Crude Cellulose

9-18

4-86 . .

9-58

25-51

Pentosans
Lisrnin .

5-49
4-13

3-04 ..
2-14 ..

7'04
4-25

26-26
21-50

Sugars

2-20

13-40. ..'

6-34

Nitrogenous bodies . .

1-70

.. 0-58

1-59 . .

8-47

The Nitrogenous Bodies of the Cane.— These have been

found by C. A. Browne6 to be thus divided in Louisiana cane : —

Per cent, on cane.
Albumen (coagulable and soluble in pepsin) -059

Nucleins (coagulable and insoluble in pepsin) -040

Albumose and peptones (not coagulable) -033

Amido acids (aspartic acid) "145

Amido acid amids (asparagine) '232

Ammonia (NH8) -008

Nitric acid , -071

Total nitrogenous bodies .... '588

15

CANE SUGAR.

Shorey has made very detailed studies of the nitrogenous bodies in the
cane. He finds that the principal amide is glycocoll7, and he failed to identify
asparagin; glycocoll being undecomposed on boiling in alkaline solution passes
on to the molasses. By precipitation with phosphotungstic acid after removal
of the albuminoids by copper oxide, he isolated a mixture of lecithins8 the
alkaloidal basis of which he identified as betaine and choline ; the lecithins
being decomposed on boiling accounts in his opinion for the presence of
fats in the second and third bodies of the evaporators. The only xanthine
base found by Shorey was guanine9, which accumulates like the glycocoll in
the molasses.

Fibre.— By fibre is meant that portion of the cane insoluble in water;
C. A. Browne6 found the crude fibre to consist of: —

Crude Fibre in

Pith. Bundles. Rind.

Per cent. Per cent. Per cent.

Ash 1-68 .. 3-58 .. 1-64

Fat and Wax '41 . . '72 . » '98

Protein 1'94 .. 2'00 .. 2'19

Cellulose (Cross & Bevan) 49'00 .. 50-00 .. 51-09

Pento'sau's (Furfuroids) . . . . 32-04 . . 28-67 . . 26*93

Lignin 14-93 .. 15-03 .. 17'17

and when calculated to 100 parts pure cane fibre, protein, ash and fat free,

Per cent.

Cellulose (including oxy cellulose) 55

Pentosans (xylan and araban) 20

Lignin 15

Acetic acid 6

Similar results were obtained by Geerligs10 in Java.

Cane "Wax. — This body occurs on the rind of the cane and in some
varieties is almost absent ; it has been exhaustively studied by Wijnberg.11
Generally dry press cake contains up to 10 per cent, to 12 per cent, of wax ;
about 70 per cent, of the crude body consists of the glycerides of oleic,
linolic, palmitic, and stearic acids, with hydroxyacids, resinacids, lecithin,
phylosterol, aromatic and colouring matters ; the remaining 30 per cent,
contains about 45 per cent, of myricyl alcohol and 35 per cent, of a non-
primary crystalline alcohol, with at least one other body. These data refer to
the benzene soluble bodies in press cake. At the moment of writing attention
is being paid to the commercial recovery of this body.

Pectin. — This body, also referred to as gums and alcoholic precipitate,
is of uncertain and indefinite composition ; it occurs in the cane up to as much

16

FIG. 9.
BOURBON

4

SIZE

PLATE I

THE COMPOSITION OF THE CANE.

as *2 per cent., and is present in largest quantity in unripe cane. It is soluble
in water and insoluble in acidified alcohol ; the lime compound of pectin is
moderately soluble in water, and more so in sugar solution ; some of the
pectinous bodies are precipitated by lime in the process of manufacture, and
some are found in the molasses.

REFERENCES IN CHAPTER II.

1. I.S.J., 90 and 91.

2. Cultur de la Canne a Sucre, p. 154.

3. Stubbs' Sugar Cane, p. 89.

4. Stubbs' Sugar Cane, 333.

5. I.S.J., 33.

6. Louisiana Bulletin, 91.

7. J.A.C.S., 19, page 881.

8. J.A.C.S., 20, p. 113.

9. J.A.C.S., 21, p. 809.

10. I.S.J., 96, p. 619.

11. Abs. in Jour. Soc. Chem. Ind., 28, 991.

17

CHAPTER III.

KANGE AND CLIMATE.

The sugar cane is essentially a tropical plant, but under certain favourable
conditions is successfully cultivated in sub-tropical districts.

The extreme limits of its cultivation are the South of Spain (36°-37° N.),
Japan (SO^SS0]^.), and Georgia, U.S.A. (32° N.), on the one side, and Cape
Colony (29°-30° S.), and New Zealand (35°-37° S.) on the other. The other
countries where the cane forms a staple product are Madeira (33° N.), Java
(6°-8°N.), the Hawaiian Islands (18°-22°K), British India (10°-30°N.), the
West Indies (8°-22° N.), including Cuba, Porto Eico, Jamaica, Martinique,
Guadeloupe, St. Kitts, St. Thomas, Antigua, St. Croix, Barbados, Trinidad ;
British and Dutch Guiana (6°-8° N.), Brazil (0°-20° S.), Louisiana (30° N.),
Egypt (22°-30° N.), Central America (8°-20°N.), the Philippines (5°-18° ff.)>
Queensland and New South Wales (10°-35°S.), Mauritius and Bourbon
(20°-22°S.), Natal (30° S.), Fiji (22° S.), Formosa (22° K), Southern China
(10°-30°N.), the Straits Settlements (0°-10°N.), Peru (5°-22°S.), Argentina
(22°-25°S.).

Humidity. — Starting with Wray (1848) a warm and moist climate
has been stated to be specific to the successful growth of the cane, and prox-
imity to the sea often has been given as a favourable factor. Thus Wray1
writes: "The climate most congenial to the cane is of a warm and moist
character, with moderate intervals of hot, dry weather, attempered by the
refreshing sea breezes. It has always been found to grow most luxuriantly
on islands, and along the sea coasts of the mainland; which leads us to conclude
that the saline particles borne on the sea breeze exercise a powerful effect on
the growth of the plant."

Delteil2 expresses himself in terms similar to Wray. " The sugar cane,
originating from India and Eastern Asia, demands a warm, moderately moist
climate, with intervals of dry heat; it loves sea breezes because of the
particles of salt which are carried to the fields and increase their fertility."

According to Boname,3 " a warm and moist climate is the most favourable
to the growth of the cane, and it is in islands and on the sea coast that the
most luxuriant plantations are seen, for it is there that are found together
the conditions of heat and moisture demanded for its greatest development."

18

RANGE AND CLIMATE.

Stubbs4 in commenting on these statements is most certainly right in
. attributing the maritime position of many sugar districts to economic reasons ;
an inland sugar estate in a tropical country would be deprived of means of
access to the world's markets. Where a local market exists the cane is grown
successfully in districts remote from the sea, as in Queensland, Brazil,
Argentina, and India; and some insular districts, such as certain of the
Hawaiian Islands, have a climate the reverse of moist.

Temperature. — The effect of temperature on the cane is very com-
plex ; the rate of growth, the time to maturity and the composition of the
cane are all affected. The rate of growth is probably directly connected with
the temperature, increasing as the temperature rises ; exact measurements
are difficult to make ; in the more equatorial cane growing districts the tem-
perature variation is so small that differences in the growth at different
periods of the year cannot be noticed. Definite measurements have been
made in Hawaii by C. F, Eckart5 in connection with varieties; the length
and diameter of internodes formed during the hot and cool seasons were
measured; generally the length of the internodes formed during the cold
season was more than 30 per cent, and less than 50 per cent, less than those
formed during the hot season ; the diameter of the internodes formed during
the cold season was also less than that of those formed during the hot season.
The time to maturity as indicated by the appearance of the arrow is directly
influenced by the temperature ; in equatorial districts, such as Demerarar
Bourbon canes planted in December arrow in September, the time from
planting to arrowing being approximately 270 days. In districts just within
the tropics, such as the Hawaiian Islands or Mauritius, the arrow in the
Lahaina plant cane will not appear for approximately 500 days ; the colder
climate takes a longer period to bring the plant to maturity, but the total
amount of heat received in the two instances is very similar.

In the extra tropical cane growing districts, such as Louisiana, the low
temperature of the winter months prevents the cane being turned over from
one season to the next, and the crop has to be grown in a short period of
growth ; an immature cane, combined with low sugar content and high
content of reducing sugars, results ; the reducing sugars in this case represent-
ing material which would be converted into cane sugar if a longer period of
growth were possible.

On the other hand, in districts where a high temperature continually
prevails, such as in Demerara, a cane low in sugar and high in impurities and
reducing sugars frequently occurs; in such districts there is a continuous
growth of the cane, and the crop as it reaches the mill will in general consist
of cane of all periods of growth, over-matured, ripe, and in full vegetative
vigour.

19

CANE SUGAR.

A very sweet and pure cane is found in those districts where the average
temperature is such that a longer period is taken to maturity, and where
a season cold enough to check the growth of the cane occurs ; when this
arrest of growth happens, the energy of the cane is presumably directed
towards the elaboration of the material already formed, rather than to the
formation of new substance; it is in the districts lying on the confines of
the tropics that this phenomenon happens.

Rainfall. — The amount of water essential to the best growth of the
cane is discussed in the chapter on irrigation. Under natural conditions an
excessive rainfall results in a cane of low sugar content, a deficiency in
rainfall resulting in a cane with much fibre. The optimum rainfall is,
of course, directly correlated to the prevailing temperature, the soil evapora-
tion increasing with rise in temperature ; thus Stubbs,6 referring to Louisiana
conditions, gives an annual rainfall of about 60 inches as most advantageous,
of which about 45 inches should fall in the wet or growing season, and about
.15 inches during the dry. Such an annual rainfall would be classed as a
severe drought in Demerara, where a precipitation of about 100 inches
results in the maximum crop ; the rainy season there should commence in mid
December, and continue without prolonged intervals of drought to the end of
July, the earlier months of the year being dry enough to allow of the
cultivation of the heavy clay soils. A heavy rain immediately before harvest
is reflected in a diluted juice, the vessels which carry plant food being then
full of water at the moment of cutting.

Wind. — The chief effect of winds in regard to agriculture, whether of
the cane or otherwise, is concerned with the removal of soil moisture ; the
more frequently the stratum of air over a soil is removed, the greater is
the soil evaporation. The point of the compass from which the wind blows
is of influence in this connection ; a wind blowing from the sea to the land
conveys air heavily charged with moisture, increasing the humidity of the
atmosphere, and lessening the tendency to soil evaporation ; it is probably for
this reason that in Demerara surface evaporation from exposed shallow vessels
is small compared with what would be expected from temperature conditions
alone. The surface evaporation there is 35*12 inches, per annum, compared
with 31-04 inches at Oxford, and 82-28 inches at Bombay.7 In Demerara the
prevailing winds are the North-east Trades, blowing directly from the Atlantic,
with no intervening mountains to cause a deposit of water as rain. Maxwell8
in Hawaii found that 120 square inches of exposed area evaporated in 270 days
33,480 grams, of water, the relative humidity being 79'5, and the average
temperature 79-5 ; this is equivalent to an evaporation of 28-4 inches per
annum. Under equal conditions, but with the water protected from the wind,

20

RANGE AND CLIMATE.

the evaporation was equal to 12' I inches per annum. This experiment was
made to estimate the effect of wind on soil moisture ; in this determination
the wind-exposed water was sheltered from the direct rays of the sun.

When the wind reaches a high velocity mechanical damage to the leaves
is very evident, and when the wind becomes cyclonic the whole growing crop
may be destroyed, as happened in Mauritius in 1892.

To a certain extent the effects of wind may be mitigated by the judicious
planting of wind breaks. Such a wind break of Casuarina equisetifolia is to be
found on a very large scale at Lihue Plantation in the Hawaiian Islands. The
sea front of this estate is girdled by a wind break extending for several miles,
and covering altogether 600 acres. When in Demerara, the writer always felt
that no inconsiderable benefit would accrue if on those flat, wind-swept estates
all the cross dams and other available areas were planted with trees.

Variety and Climate.— It may be said that all varieties of cane-
attain their maximum growth in the more essentially tropical districts ; some
varieties, on the other hand, fail entirely when removed to these latter
districts.

It seems probable that adaptability to a colder climate is a characteristic
of the red and purple canes. In a subsequent chapter it will be shown that
the light and dark Cheribon (Transparent, Bamboo, &c.,) canes in all probability
originated from striped canes. Stubbs9 states that in the relatively cold
climate of Louisiana a plantation of striped canes if not renewed tends to pass-
into one of all purple canes, and classes this phenomenon as a case of the
" survival of the fittest," attributing to the purple colour a greater capacity to
absorb heat.

The cane known as Cavengerie, Port Mackay (in Mauritius), Louzier (in
the Argentine), Po-a-ole (in the West Indies), is also another instance of a
dark coloured cane being adapted to a cold climate. In the less tropical
portions of South America this variety is one of the canes most widely
grown.

In the Hawaiian Islands the Lahaina cane forms the bulk of the crop on
the irrigated plantations in the arid districts, chiefly at a low altitude ; it is
replaced by the Yellow Caledonia on the rainfall plantations situated mainly
at a higher level, and hence with a colder climate. A peculiar case of suit-
ability to climate is to be found in the D. 74 cane which has conferred so great
a benefit on the Louisiana industry ; suitability to the climate of Louisiana is
in this case due to the early maturity habit of the variety. The adaptability
of a variety to a cold climate does not in any way imply that it will fail in

21

CANE SUGAR.

a hotter one, as the purple cane of Louisiana formed for many years, under
the name of Cheribon, the standard cane of tropical Java.

A further instance of the connection between variety and climate is to be
found in the success of the Uba cane in extra tropical Natal and Madeira,
localities unsuitable for the growth of the canes of the Otaheite type ; in fact
it may be said that every locality is suited for the growth of one or another
variety to its best advantage.

REFERENCES IN CHAPTER III.

1. The Practical Sugar Planter, p. 48.

2. Le Canne a Sucre, p. 37.

3. Culture de la Canne a Sucre, p. 13.

4. Stubbs' Sugar Cane, p. 13.

5. BuH. 17, Agric. H.S.P.A.

6. Stubbs' Sugar Cane, p. 31.

7. Hilgard's Soils, p. 256.

8. Butt. 90, U.S.D.A., p. 9.

9. Stubbs' Sugar Cane, p. 77.

22

CHAPTER IY.

VARIETIES OF THE CANE.

Owing to lack of communication between sugar-growing districts, and
to absence of systematized work in all but the more recent phases of the cane
sugar industry, great confusion has arisen in the nomenclature ; a cane intro-
duced from one district to a second receives a name usually connecting it with
the introducer or with the district whence brought ; the same cane travels
from the second district to a third, and there receives a name connecting it
with the second district, and not with its original home. On the other hand,
two different canes may be introduced from one district into two widely
separated countries, and in this case they may receive, in both cases, the same
name. In these ways, names for the principal varieties have multiplied until
a variety may have as many as twenty titles, and to add to the confusion some
of these titles may be applied to other quite distinct varieties.

Much of the confusion has been cleared away by means of the detailed
descriptive lists of canes growing in the botanical gardens and experiment
stations in Jamaica, Louisiana, Demerara, and Java, published by Fawcett1,
Stubbs2, Harrison & Jenman3, and by Soltwedel4. Comparison of these lists
lays bare many irregularities due to the causes mentioned above. Eckart and
Deerr5 made an effort to reconcile many of these statements, and to collate
the literature of the subject. Eelow are described, in detail, the more
important varieties of the sugar cane.

The Otah.ei.te Cane. — Wray6, in 1848, described two canes under
this topographical heading, — the yellow and the purple striped; in this section
only the former is considered. From the island of Otaheite a yellow cane or
canes has been introduced into many cane-growing districts; instances are that
by Captain Bligh into Jamaica in the 18th century, and into Hawaii by Captain
Pardon Edwards in 1854 ; also in the 18th century a yellow cane was intro-
duced into the French West Indies from the island of Bourbon. Wray gives
the presumptive origin of this last as the Malabar coast of India.

The principal names that have been applied or identified as belonging to
this cane are Bourbon (British West Indies), Lahaina (Hawaii), Otaheite (Cuba
and Java), Louzier, Keni-keni, Portii, Cuban. China, Bamboo II., and
Cayenne are also names connected with this cane.

There is considerable reason for supposing that this cane includes two
very similar but distinct varieties, for Stubbs2 identifies the canes growing at
Audubon Park under the names of Yellow, Otaheite and Louzier ; and those

23

CANE SUGAR.

under the name of Portii, Lahaina and Keni-keni. Harrison and Jenman*
identify Bourbon, Cuban, Lahaina, and Otaheite, but separate Keni-keni.
This difference of opinion can be reconciled by assuming that there are two
similar canes, and that the names proper to one variety have been applied to
the other ; great probability is lent to this view in the following account of the
origin of the Lahaina cane: —

Mr. D. D. Baldwin, in a letter appearing in the Hawaiian Planters'
Monthly, for May, 1882, states that in 1854 Captain Edwards, in the ship
'George Washington,' brought two varieties of cane from Otaheite (not from the
Marquesas) ; these two varieties are now (1882) known as Cuban and Lahaina,
the Cuban also obtaining the name 'Oudinot.' To the Cuban was also applied
the term Keni-keni, from the native term Mnikini, * numerous,' in reference
to the prolific nature of the cane.

Mr. Baldwin thus distinguishes between these two canes.

Lahaina. — Long straight leaves of light colour, heavily aculeated, or
covered with prickles at the base, with small round prominent buds.

Cuban. — Leaves of darker green, bending down in graceful curves, with
no prickles, and large triangular buds, located in little cavities on the side of
the cane stalk.

Mr. Baldwin further states that in 1861-62, Cuban was the favourite
cane, and that it afterwards gave way to Lahaina, the latter possessing these
advantages : rapid growth, deep rooting, hard rind when mature, superior
richness of juice, firm compact fibre, making the trash easy to handle, and
enhancing its value as fuel.

The Louzier cane is one that has been and still is extensively grown in
Mauritius, and its origin is entirely different. In a letter received by the
writer in 1908, from M. Auguste Yillele, of Mauritius, its origin is stated as
follows : — In 1868 or 1869, M. Lavignac introduced into Mauritius several
varieties of cane from New Caledonia, amongst which was the Mignonne, a
red and green striped cane. This cane when cultivated was noticed by
M. Louzier to throw sports, and from a yellow sport was developed the cane-
which for many years formed the standard cane of Mauritius. It is certain
that the Louzier cane, which has travelled from Mauritius to other districts, is
not to be distinguished from the Yellow Otaheite cane (or canes) ; and the
writer, who has seen the Bourbon, the Lahaina, and the Louzier on the large
scale in Demerara, in Hawaii, and in Mauritius, has no hesitation in saying
that grown on the large scale they are indistinguishable. It is then reasonable
to suppose that the Lahaina and Bourbon canes, although introduced as self-
coloured canes, were originally in Otaheite sports from the cane introduced
into Mauritius in 1868 or 1869 under the name Mignonne, and that in Otaheite
the latter was cultivated by the natives as a separate cane.

24

VARIETIES OF THE CANE.

The following irregularities may be noted in connection with the names
applied to this cane (or canes) : —

1. In Keunion a purple cane (the Black Cheribon, &c,, see Mow) is
called Otaheite.

2. The Bourbon, described by Stubbs as so called in the collection at
Audubon Park, is the White Cheribon, &c., as described below.

3. In Jamaica the Otaheite cane is, according to Cousins,9 the White
Transparent, i.e., White Cheribon.

4. The name Portii was originally applied to a chalky grey-coloured cane
in Mauritius.

5. Owing to confusion in transport of the original cuttings, the name
Louzier in Brazil is applied to the cane described below as Cavengerie.

6. The Loethers (Louzier) cane of Java, as figured and described by Soltwedel
and by Eriiger,7 is a brown cane distinct from the Otaheite.* Prinsen Geerligs
states that a cane called Bourbon was introduced into Java from the Straits in
1890, and describes it as being very similar to the Cheribon.

This cane is shown in Fig. 9\; the illustration was prepared from a ripe
Louzier cane in Mauritius. For generations this cane has been responsible for
a very large proportion of the world's supply of cane sugar, and it combines
the characteristics of heavy tonnage, sweet and pure juice, and lowfibre, which is
of such mechanical structure that it affords a megass of good fuel value. In
the Hawaiian Islands under irrigation it has many times given over ten
tons of sugar to the acre and purity in the mixed mill juices of over 90. Its
great failing is its susceptibility to fungus diseases, which accounts for its
partial disappearance from the British West Indies and Mauritius. It is a
shallow rooter, and hence not a drought-resisting cane, and does not succeed
without the tropics, or in tropical countries at higher elevations.

Harrison and Jenman's description3 of the Bourbon cane is appended :

Bourbon. — Canes few or several, of average length, girth and length
of internodes, sub-erect or trailing, nodes constricted, colour yellowish or
green, suffused crimson where sun exposed. Arrows, some well and others
badly projected. Panicle arrested or well developed, large and copiously
branched and flowered.

Below are collected the names that have been applied to this cane (or
canes) ; this list should be read in connection with what has been written
above.

Otaheite, Bourbon, Louzier, Portii, Tibboo Leeut, Keni keni, Cuban,
Bamboo II., China II., Colony, Lahaina, Singapore.

* See Note in Appendix. t See Coloured Plates.

25

CANE SUGAR.

The Cheribon Canes.— Wray6 in 1848 describes four canes as
Batavian canes ; the yellow violet, the purple violet, the transparent or ribbon
cane, and the Tibboo Batavee of the Straits ; the first three only are considered
in this section.

As will be pointed out later, the yellow violet and the purple violet canes
have originated, and repeatedly originate, as bud sports from the ribbon cane.

These canes have been introduced into nearly all cane-growing districts ;
the purple variety has been especially grown in Java, where it is known as
the Cheribon or Black Cheribon, in distinction to the White and Striped
Cheribon canes. In the British West Indies the light- coloured variety has
been grown extensively under the name of White Transparent, and the purple
variety as the Purple Transparent ; in Cuba the light-coloured variety has
been and is extensively grown under the name of Crystallina ; also in Hawaii,
where it is known as Rose Bamboo. In Mauritius a generation ago the purple
variety there called Belouguet was under extensive cultivation. In Louisiana
both the purple and striped varieties form standard canes under the names of
Home Purple and Home Ribbon, and in Australia the light and dark-coloured
varieties are also grown under the names of Eappoh and Queensland Creole.

In the Java literature the term Cheribon applies almost exclusively to
the dark-coloured variety ; this cane was established by Gonsalves as the
standard cane of Java in the middle of the nineteenth century in the face of
great opposition, and many references are to be found describing the great
benefits thus due to Gonsalves. Though this cane was the one which
eventually succumbed to ' sereh ' and is now largely replaced by seedlings,
it has been the female parent of many of the best of the later varieties.

The light- coloured variety shown in Fig. 10* is of rather less diameter
than the Otaheite cane, and is peculiar in having no distinctive colour, but
being very susceptible to environment ; Wray's term of yellow violet well
expresses its colour, and at various stages of growth, yellow, violet, pink and
grey shades of colour appear ; the leaves are of a darker shade of green.

The dark-coloured variety, Fig. 11* is of a purple colour and of slender
habit ; the internodes are long in proportion to girth, and the foliage of a
lighter shade of green.

The striped variety, Fig. 1$* which it is possible to confuse with the
Striped Tanna, is of similar proportions to the light and dark varieties ; it is
striped yellow and blood red, the yellow portions having a polished appear-
ance, whence the term 'Transparent.' All three of these canes are
characterized by a longitudinal channel running upwards from the eye.

The identity of the Cheribon aud Transparent canes of the West Indies is
made certain beyond reasonable doubt by the following statement due to
Kriiger.8 " In Barbados, a little Bourbon is still grown, but the Purple

* See Coloured Plates.

26

VARIETIES OF THE CANE.

Transparent (probably identical with the Black Cheribon) is chiefly planted,
then the Ribbon Transparent and the White Transparent" (which are
presumably the Striped Cheribon and the White Cheribon).

In the Java literature relating to cane tests, the cane 'Striped Preanger'
is frequently mentioned ; in a discussion at the Sugar Congress, at Soerabaya,
in 1900, it was stated that the Black Cheribon or Gonsalves cane was at an
early date introduced from the Cheribon district to the Preanger district.
Under the conditions there the stock grew into the striped form, which was
then selected by the planters ; hence this cane is probably none other than the
original Transparent of Wray, Red Ribbon, &c.

As sugar producers, these canes are of equal importance with the Otaheite.
Compared with this cane they are not such heavy croppers under tropical
conditions, but are especially suited for colder districts, owing to their habit of
early maturity. This is especially true of the striped and dark-coloured
varieties, and in Louisiana Stubbs has observed a tendency for the striped
cane to pass eventually into the self-coloured dark variety, the dark variety
being more adapted to the comparatively cool climate. All of the varieties are
of a ' hardy ' nature and afford renumerative crops on soils where the more
delicate Otaheite will fail, and also under less careful cultivation ; though not
immune to disease they are less susceptible than the Otaheite, and when grown
in Demerara the light-coloured variety afforded a megass of such mechanical
structure that it was difficultly combustible.

To these varieties a large number of names have been applied, which are
collected below: —

Light Coloured Variety. — La Pice, Le Sassier, Panachee, Rose Bamboo,
Mexican Bamboo, White Transparent, Naga B, Blue, Hope, Light Java, Mont
Blanc, Rappoh, Crystallina, Tibboo Mird, Green, Mamuri, Yellow Singapore,
White Cheribon, Burke.

Dark Coloured Variety. — Louisiana Purple, Black Java, Purple Trans-
parent, Black Cheribon, Tibboo Etam, Purple Violet, Belouguet, Tabor Numa,
Queensland Creole, Purple Mauritius, Purple Bamboo, Moore's Purple, Dark
Coloured Bamboo, Meera, Gonzalves, Diard.

Striped Variety. — Transparent, Striped Mexican, Striped Louisiana, San
Salvador, Seete, Striped Bamboo, Red Ribbon, Striped Cheribon, Home Ribbon,
Mauritius Ribbon, Diard rayee, Striped Preanger.

The following irregularities in nomenclature may be noted in connection
with these canes : —

1. The purple variety is termed Otaheite cane in Bourbon.

2. The term Bourbon is applied to the light-coloured variety in the
collection at Audubon Park.

3. In Jamaica the light-coloured variety is, according to Cousins9, the
Otaheite cane.

27

CANE SUGAR.

4. Stubbs states that the striped variety came originally from Tahiti, and
is generally known as the Otaheite Bibbon cane (see Tanna cane).

5. In Demerara a cane introduced under the name Meera is identical
with the Purple variety ; the term Meera in Malay means red, and is applied
to any red cane ; the Tibboo Meera of Soltwedel is entirely distinct from this
cane.

6. The term Rappoh is apparently an East Indian word applied to a
number of canes; the Tibboo Rappoh of Soltwedel is a cane of a greenish-
brown colour with a well marked bluish-white layer of wax at the node ;
canes of the name Rappoh Kiang, Rappoh Maeda, Rappoh Koenig, and White
Rappoh also are known.

7. In Queensland the term Cheribon is applied to the Cavengerie cane10
(see below).

8. The name Seete is given by Pawcett and by Dahl & Arendrup11 to a
greenish-yellow or white cane.

9. The term Crystalline has also been given to the Salangore cane.

10. The Teboe Soerat Mauritius of Soltwedel is an entirely distinct cane.
Harrison & Jenman's3 description of these canes under the names White

Transparent, Purple Transparent, and Red Ribbon, is appended : —

White Transparent. — Canes several, erect and partly trailing, of full
average length, barely of full average girth, nodes superficial, internodes of
full or over average length, colour at first pink, finally a grey horn tinge in
the lower part, and yellow tinged with pink in the upper half, rarely blotched
with carmine where sun exposed. Arrows projected well aloft. Panicles
full size, copiously branched and flowered.

Purple Transparent. — Canes several or many, full average length, barely
average girth, full or over average length of internodes, nodes superficial, cane
and internodes very straight, colour at first purplish, finally claret and stone
grey. Arrows high projected. Panicles large, copiously branched and flowered.

Red Riblon. — Canes several, erect, or with some trailing, of full average
length, barely of full average girth, long internodes and superficial nodes,
colour in part pink and greyish, in part striped pink and claret and yellow.
Arrows projected well aloft. Panicles full sized, copiously branched and
flowered.

Tanna Canes. — In Mauritius at the beginning of the twentieth
century, three canes, known as the Striped Tanna, White Tanna, and Black
Tanna, were in extensive cultivation. The two latter were known to
frequently originate from the striped variety precisely as the white and black
Cheribon canes originate from the striped variety. The following identities
may be given from the writer's personal experience and from his correspondence
with others familiar with the sugar cane.

28

VARIETIES OF THE CANE.

Striped Tanna = Big Ribbon = Guingham = Maillard.

White Tanna = Yellow Caledonia = Malabar.

Of the Black Tanna no synonyms, as far as the writer is aware, exist.

The Striped Tanna is beyond any reasonable doubt the cane described by
Wray as the Otaheite Ribbon, and which he particularly distinguishes from
the ' Ribbon Cane of Batavia ' (Striped Cheribon). The latter he states
is smaller than the Otaheite Ribbon, and is striped blood-red on a transparent
straw-coloured ground, compared with the broad purple stripes on a greenish-
yellow ground. In addition Delteil12 states that the Otaheite Ribbon of Wray
is synonymous with the Guingham and Maillard. A cane mentioned by
Wray6 as peculiar to the island of Tanna, and identified by him with the
Tibboo teelor, or egg cane, is described in terms applicable to the White Tanna.
He remarks on its extreme cleanness, or absence of cane-itch, habit of shedding
its dry leaves, brittle nature and large eyes ; he however mentions that this
cane has a habit of bulging between the nodes, a characteristic which is not
usually found in the White Tanna.

Of these three canes the light self-coloured variety is by far the most
important ; at the time of writing, under the name of Yellow Calendonia,
it forms the bulk of the cultivation on the unirrigated estates in the Hawaiian
Islands; as Malabar, it is the favourite cane of Fiji, and as White Tanna
covers extensive areas in Mauritius. All three of the Tanna canes are also
cultivated in Australia on the large scale, on the Clarence River the striped
variety being incorrectly known as Daniel Dupont.

The striped variety is distinctly short- jointed in proportion to girth, a
character which is less pronounced in the white and black varieties ; all contain
more fibre than does the Otaheite cane ; in Hawaii, when grown under the
same conditions, the Yellow Caledonia cane will contain 13 per cent, fibre
when the Lahaina contains 12 per cent., and the percentage of sugar is in a
reverse ratio. They all possess a hard rind, and are thus protected to some
extent against the attacks of insects, and are so to be considered comparatively
immune to fungus diseases. The megass afforded by them is of such a
mechanical structure that it offers a serviceable fuel, but their hard nature
offers considerable resistance to milling, and makes a crusher or other
preparatory appliance a necessity ; generally speaking they are deep rooters,
and suffer only to a limited extent from the effects of drought. These three
canes are shown in Figs. 13, 1^ 15* The White Tanna is represented as of a
reddish tint; this coloration is very pronounced at certain stages of its growth,
while at others the colour is yellow.

In parts of Australia the name Daniel Dupont is applied to the Striped
Tanna ; an imported cane of this name at the H.S.P.A. Experiment Station is

* See Coloured Plates.

29

CANE SUGAR.

green with red streaks rather than stripes and remarkable for the intense
whiteness of its ground tissue.

In my earlier work, " Sugar and the Sugar Cane," I stated that the Black
Tanna was the same as the Tibho Etam or Black Java, and that the Striped
Tanna was the Cherihon cane. This very serious mis-statement I now know to
be an error ; it was made on the verbal information of a Java resident of several
years' standing. On the same authority I said that Tanna was the Javanese
term for ' rich earth} whence was derived the name of these canes ; the term
Tanna in this case actually refers to the island of that name in the South
Pacific; 'tanah' is, however, a Javanese word roughly equivalent to 'clay.'
The SalangfOre Cane. — Wray6 describes this cane as, in his opinion,
the finest in the world. He mentions that it is remarkable for an excessive
quantity of cane itch ; that the leaves when dry are peculiarly adherent, and
comments on the large amount of cane wax on the stem, whence have arisen
the Malay terms Tibboo biltong berabou and Tibboo cappor.

Wray's opinion has not been supported by other planters, and the
following remark due to Harrison13 aptly describes this cane : —

" Some of us will doubtless recollect the time when Mr. A. would plant a few
acres of Salangore cane in the hopes of getting better field returns, and richer cane
juice ; how these Salangores in some years flourished and raised hopes of heavy
returns of sugar, how in others they unaccountably languished; but how, whether
they flourished or languished, one thing invariably characterized them — miserably
poor juice and consequent loss of money."

In the literature of sugar cane expressions of opinion leading to similar
conclusions can be found, the cane being sometimes condemned, and at other
times referred to in extravagant terms ; it is so well characterized however that
there seems to be no possibility of doubt as to its identity, and the conclusion
is reached that it is a variety particularly susceptible to obscure local con-
ditions. This cane at the time of writing does not seem to be under extensive
cultivation ; it is apparently grown to some extent in Porto Rico and Brazil,
and is again being cultivated in Demerara under the name of Green Trans-
parent. In Spanish writings dealing with the sugar cane a variety is referred
to as Canne Rocha, or Waxy cane, which in certain references would appear
to be this cane. Harrison and Jenman3 thus describe this cane as it appears in
the Georgetown Botanical Gardens : —

Salangore. — Canes numerous, erect, rather under average height, of
nearly average girth, much under average length of internodes, nodes slightly
contracted, colour whitish or greyish, suffused often with a grey hue, and
touched with carmine where sun-exposed. (Rarely arrows.) Panicles large,
copiously bunched and flowered, and well projected.

In addition to the native Malay terms of Tibboo biltong berabou and
Tibboo capper given by Wray, Delteil gives Pinang and Chinese (in Bourbon)
as synonyms, and Harrison and Jenman give the name White Mauritius (in
Demerara), and the term chalk cane is also met with.

30

VARIETIES OF THE CANE.

In the literature of the cane the name Crystallina can occasionally be
found applied to the Salangore, and the use of this term has led to identifica-
tion with White Cheribon.

Purdie14 in Trinidad termed two unnamed varieties, Green Salangore and
Yiolet Salangore ; his description of the former is broadly applicable to the
White Tanna.

The Cavangerie Cane. — This cane, which must be included
amongst the world's standard ^varieties, is also known under the names of
Altamattie, Po-a-ole, and Port Mackay, under which name it has been
extensively cultivated in Mauritius.

It is a claret-coloured cane with an inconspicuous yet clearly defined
bronze-green, almost black, stripe, and possesses the peculiarity of not infre-
quently growing variegated or albino leaves.

It is a cane that affords a juice less pure and sweet than that given by
the above discussed varieties, but, being of a ' hardy ' nature, and adapted to
colder temperatures, is successfully cultivated in the less tropical cane-growing
districts, and at higher elevations in the more tropical ones. It has been
most extensively grown in Mauritius, in Brazil, and in Australia.

In Australia this cane is called Cheribon.

In Brazil the name Louzier has been applied to this cane.

The name Port Mackay in Java is given to a totally distinct cane, and
described by Kriiger 7 as a yellow-green cane with very handsome prominent
brown blotches where sun-exposed.

Harrison and Jenman3 thus describe this cane : —

Po-a-ole. — Canes several or numerous, of full average height, girth and
length of internodes, nodes superficial, colour light reddish claret. Arrows high
projected. Panicles large and copiously branched, very plentifully flowered.

This cane under the name of Port Mackay is shown in Fig. 17.*

Bamboo Canes. — The term Bamboo has been applied to a large
number of totally distinct varieties. The Striped Bamboo is a synonym of
the striped Cheribon cane, and hence have probably arisen the names of Rose
Bamboo and Purple Bamboo applied to the light and dark coloured sports from
the striped variety.

Bamboo II. is given by Harrison and Jenman 3 as a synonym of the
Otaheite, and Bamboo I. and III. as identical with another yellow cane known
as Meligeli or Demerara.

In the Hawaiian Islands a cane successful at high elevations passes under
the name of Yellow Bamboo. This cane is alleged to be a * graft.' It is a
rather small yellow cane with a narrow rich green leaf, the sheath of which is
thickly covered with prickles ; the internodes are slightly convex, and the eye

* See Coloured Plates.

31

CANE SUGAR.

is small and round. According to priority in the literature of the cane, the
term Bamboo should be applied to the Kulloa, Kullore, or Culleroah cane of
India. Porter15 describes it as a light-coloured cane growing to a great
height, and to be found on swampy land. Delteil12 describes it as of a
yellow, pale green, and pink colour, Stubbs in addition calling attention to its
enlarged nodes and prominent eyes.

Bois E,OUge. — This cane is under a limited cultivation in Mauritius:
it is an olive green cane heavily blotched with red ; it is of slender and erect
habit, with long slightly concave Intel-nodes.

Settlers. — This cane has been introduced to Australia from Mauritius :
it is a dull green thin erect cane with medium internodes ; the rind has a
tendency to crack : the eyes are prominent and pointed.

Tip Canes.* — Two canes successful at higher elevations in the Hawaiian
Islands are known as the Striped Tip and the Yellow Tip canes, the latter
being a sport from the former.

The striped variety is a small thickly stooling cane, striped dark red and
pinkish green, changing at maturity to yellowish-red and yellow. The
sheaths of the young leaves have light purplish margins, and are covered with
long prickles which rub off easily, and disappear as the leaf dries. The eye is
large, long and pointed ; nodes prominent, internodes concave ; the internode
is channeled from the eye upwards.

The self-coloured variety is a light green cane, turning yellow at maturity ;
it resembles the striped variety, except that the prickles on the sheath are
fewer, and the purplish margin on the leaf sheath is absent. This cane is
referred to in some of the publications of the Hawaiian Sugar Planters' Station
as 'Unknown/

— This cane is at the time of writing cultivated with success in
Madeira and Natal ; that is to say, in extra tropical countries. It is stated
by John Dymond16 to be identical with the Zwinga or Japanese cane described
by Stubbs2, who states that it is extremely hardy, enormously productive
under good cultivation, extremely woody, and of moderate sugar content.

The Elephant Cane.— The true Elephant cane originates from
Cochin China; it is relatively an enormous cane, and is allowed to grow
undisturbed for a period of years as an ornamental plant ; it may in five or six
years reach a height of 30 feet. It is of absolutely no importance as a sugar
producer. The Elephant cane is figured by Soltwedel4 under the name Teboe
Oadjah ; as shown by him it is of a very dark greenish-grey, almost black
colour irregularly blotched with greenish-yellow patches.

* See Note in Appendix.
32

FIG. 10.
ROSE
BAMBOO.

4

SIZE

PLATE II

VARIETIES OF THE CANE.

The Creole Cane. — This term occurs frequently in the literature
and its history is apparently as follows. The Crusaders brought to Southern
Europe a cane from the Orient ; this cane was cultivated in Sicily, Southern
Spain, the Canaries, Madeira and eventually reached the New World ahout
1500; later when the South Pacific types were introduced, it was necessary
to name this cane, when by reason of its already long association with the
colonies it was called ' Creole.'1 It is a small yellow cane probably of Indian
origin, and may perhaps be included amongst the Indian canes described in a
separate section.

Red Canes. — Wray6 describes a certain cane under the name of Red
Cane of Assam, and states that the native name is Tiboo Meerah. Kriiger7
mentions two canes to which this term is applied ; Tiboo Meerah, and Tibboo
Meerah Borneo. The Tibboo Meerah figured by Soltwedel4 is a dirty claret-
coloured cane, merging into purple on the older internodes, and this is, the
writer understands, the cane referred to under that name in the literature of
the sugar cane as it refers to Australia. Harrison and Jenman3 give Meerah
as a synonym of the Purple Transparent, but the Tibboo Meerah of Soltwedel
is quite distinct from the Purple Transparent or Black Cheribon.

Home. — This cane is of great interest, as it is one of the earliest, if
not the earliest, recorded instances of a striped cane originating from self-
coloured cane. This observation is due to Mr. John Home, at one time
Director of Forests and Gardens in Mauritius ; the cane from which it origi-
nated was a Louzier cane, and in Mauritius, where it is cultivated on the
estate scale, it is indifferently known as Louzier rayee ; the writer has also
observed occasionally a cane exactly similar to the Home appearing in
Bourbon fields in Demerara. The cane is very irregularly striped in red,
green, and yellow colours.

The Green Rose Ribbon. — This cane, which has been cultivated
with success in Australia, is a sport from the Otaheite, which it resembles in
habit ; it is striped green and a yellowish pink colour. It is also known as
Green Ribbon, Brisbane, Malay, White Striped Bourbon, and in Mauritius
as Louzier rayee.

The Iscambine Canes. — Among canes introduced into Mauritius
from New Caledonia was a striped cane originally known as Tsimbec ; this
€ane is striped yellow and red, and from it has sported a cane known as
Iscambine rouge, represented in Fig. 18.* Both these canes are found on the
estate scale in Mauritius ; they are soft canes with a brownish-yellow ground
tissue ; they are subject to variation and a number of Iscambines are
known.

Indian Canes.— S. M. Hadi17 divides the canes of the United
Provinces into Ukh, Ganna, and Paunda canes. The Ukh canes are small

* See Coloured Plates.
33

CANE SUGAR.

thin and reed-like with small and narrow leaves; the internodes are short,
the eyes small and depressed, and many varieties have a well-defined central
fistula in the stalk. The Paunda canes are the acclimatized canes admittedly
of introduced origin and under native names include many of the varieties
already described. The Ganna canes seem to be intermediate between the
TJkh and Paunda types. Mollison and Leather18 have proposed a classification
of Indian canes under five heads; their A class seems to correspond with
Hadi's Ganna and Paunda canes, their B, D, and E classes apparently,
including the TJkh canes.

The classification of the canes of India seems to be a hopeless task,
especially when the numerous dialects and races of the Peninsular are remem-
bered ; in the forties many varieties were introduced from Mauritius and
these have received local native names, adding still more to the difficulty of
classification. In addition to those mentioned above, the following may be
referred to : —

Restati. — In Madras, a striped cane, perhaps the striped Cheribon.
Nanal. — In Madras, refers generally to a reed-like cane.

Chunnee. — An Indian cane which Kobus has used as the male parent of
his hybrids, the female being the Cheribon.

Samsara. — A white cane introduced (but unsuccessfully) into the West
Indies.

Rullore. — A white cane and one to which the term bamboo seems to have
been earliest applied.

Javanese Canes. — Soltwedel4 figures and describes a large number of
canes occurring in Java ; attention has already been directed to the Cheribon,
Loethers, Meera, and Bappoe canes. Two canes illustrated by Soltwedel as
Tibboo Soerat Mauritius and Branchu blanche the writer recognises as very
similar to the Branchu rayee of Mauritius and the Cavangerie respectively; the
Branchu blanche is a self-coloured sport from the Branchu rayee, both of which
were once largely grown in Mauritius. It may be here mentioned that in the
Malayan Orient the term Soerat applies to any striped cane and not to one
particular cane.

Other canes mentioned in the Java literature are the Muntok, introduced
from Banca, immune to sereh but subject to red rot of the stem, and of inferior
sugar content and purity to the Cheribon ; the Fiji or Canne Morte, immune
to sereh, and a parent of several valuable seedling varieties ; the Bourbon, a
purple cane, and hence quite distinct from the West Indian Bourbon ; the
White, Red, and Black Manila canes, all characterized by swollen nodes, the
last of which is apparently under somewhat extended cultivation.

34

VARIETIES OF THE CANE.

New Guinea Canes. — Of late years canes have been introduced
from New Guinea to Queensland. The following descriptions are due to
Maxwell19:—

JV. G. 8a, or Gogari.— Dvill, deep green cane, of moderately stout habity
turning red on exposure ; internodes 4-6 inches ; occasionally grooved, flesh
yellow.

N. G. 15, or Badilla. — A dark purple to black cane, stout, with white
waxy rings at the nodes, internodes 2-3 inches, often longer in ratoons, of
erect habit, foliage somewhat erect, very green and in young cane often of a
reddish tinge, flesh white, of high sugar content, often weighs up to 1 Ib. per
foot.

N. G. 24 or Goru or Goru possi possana. — A moderately stout greenish
brown to copper coloured cane, joints zigzag, internodes 3-4 inches, slight waxy
bloom, basal end develops roots, upper eyes sometimes shoot, foliage broad
and plentiful, flesh yellow.

N. G. %4a °r Goru scela scelana. — Like N". G. 24 but striped with red,
moderately stout, internodes 3-4 inches, foliage broad and plentiful, flesh yellow,

N. G. %$ or Goru burnt lunana. — Like N". G. 24 in shape but of a yellow
to yellowish green colour, sometimes marked on exposure with reddish granular
spots, internodes 3-4 inches, eyes full and prominent, foliage broad and plentiful,
flesh yellow.

N. G. 64. — A brownish to olive cane striped with claret, with small
linear skin cracks, moderately stout, internodes 3-5 inches, contracted at nodes
and bulging towards centre, foliage red to purple when young, flesh white.

Pacific Islands Canes. — The following canes have been described by
Cuzent20 under native names ; the botanical names given afford the impression
that they are distinct species, while actually they are only varieties of the
species Saccharum officinarum.

To uti. S. atrorulens. — Stalk and pith violet, imported from Java by
Bougainville in 1782.

Rurutu. S. rulicundum. — Stalk and leaves violet, pith white.

Irimotu. S, fragile.— Stalk green and brittle, pith white, numerous hairs.

To our a. — Yiolet and yellow striped cane.

Piaverae. S. obscurum. — Stated to be the Creole cane.

To avae. S. fragile var. — Green and yellow striped cane.

Vaihi or Uouo. S. gldber. — A white cane introduced from the Hawaiian
Islands. Melmoth Hall thinks it possible that the Yaihi is the Otaheite of the
West Indies ; this is improbable in the light of what has already been written
on the origin of the Otaheite cane ; the Yaihi may be one of the white indigenous
canes of Hawaii such as Ko Kea. The same writer also thinks that the
To oura is the purple striped Otaheite cane of Wray, or the Guingham of
Mauritius, i.e , Striped Tanna.

35

CANE SUGAR.

Hawaiian Canes. — The native canes of these islands have been
described by C. N. Spencer21 as under : —

Ko Kea. — A greenish-white cane, not unlike the Otaheite, and the one
most commonly grown before the introduction of the latter.

Aindkea. — A green and red striped cane, which Stubbs, quoting from
a letter, says was brought from Mauritius; wbere it is known, he says,
as the light striped Bourbon ; this latter cane, though similar, is within the
writer's knowledge distinct.

Oliana. — A yellow very woody cane.

Papaa. — A purple cane.

Palania. — A purple cane.

Hillebrand, in the Flora Hawaiiensis, gives the Puaole (= Cavengerii) as
indigenous to Hawaii, but it was probably introduced from the South
Pacific.

Brazilian Canes. — The canes common in Brazil are described by
Sawyer.22

The Cay anna Antiga is evidently the Otaheite cane (or canes).

The Black cane is believed by Sawyer to be the Cheribon cane, but its
description more approaches (in the writer's opinion) to the Black Tanna.

The Imperial is a green and yellow striped cane.

The Manteiga, Envernizada, Calvacante, Flor de Cuba, San Pello, are
names applied to a butter-coloured cane.

The Aleijada, a seedling cane destitute of hairs, with one or more abortive
internodes on every stalk.

The Crystallina, the description of which fits the White Transparent, &c.

The Roxa Louzier, introduced from Mauritius.

The Salangore, the description of which fits that of this cane already given.

The Cinzenta or Grossona, similar to the Salangore when young, and at
maturity approaching the Cay anna Antiga, and referred to as being of merit.

The Ferrea or Cavengerie, a bright purple cane, and hence distinct from
the Cavengerie already described.

The Bois rouge or Termehla, introduced from Mauritius, and of a ruby-
red colour, regarded as an inferior variety.

The Bronzeada or Roxinha, resembling the Crystallina when young, and
the Antiga at maturity.

The Cayanninha, much resembling the Antiga.

Sports.— By the term ' Sport ' is meant a plant which in some way is
notably different from its parent, and whence it originates ' per saltum' ; with
the cane, sports originate by bud variation, and in view of the evidence
collected below it is established beyond reasonable doubt that certain of the
more valuable cultivated varieties have so originated. The earliest recorded

36

VARIETIES OF THE CANE.

instance of bud variation is due to J. F. Home23 who, in describing canes
imported into Mauritius, writes : — " On examining the plants of this cane at
Mon Piaisir, a plant was noticed giving green, instead of striped, canes. On
further examination two other plants were found, one of which, while
producing striped canes from one eye, produced green canes from another eye,
both of which eyes belonged to the same piece of cane, while the second plant
produced both striped and green canes from one and the same eye."

A very similar observation was made by Melmoth Hall24 a little later,
who writes : — "I have in one instance seen no less than three distinct canes
springing from one stool of the ribbon variety, one entirely yellow, one
entirely green, the other being the usual ribbon cane ; while from other stools
in the same field I found canes either of a uniform green, purple or purplish
brown ; all the rest spring from the same ribbon cane root, being striped in
the usual way."

A manuscript communication to the writer from M. Auguste Villele, of
Mauritius, ascribes the origin of the Louzier cane of that island to a sport
from a striped cane known as Mignonne, imported from New Caledonia ; this
sport was observed by a M. Louzier. In the early nineties the Striped Tanna
canes were brought to Mauritius, and these were observed frequently to throw
sports, whence have come the White and Black Tanna canes. Other instances
are recorded in the West Indies where the Red Ribbon (cp. supra under
Cheribon canes) is known to give self-coloured canes identical with the Burke,
and J. F. Clark,25 of Queensland, has recorded that the Striped Singapore
cane there throws sports which are apparently identical with the Rappoe.
The Red Ribbon and Striped Singapore canes are synonomous, as are also the
Burke and Rappoe varieties.

It has been shown above that the White and Black Cheribon canes have
been and are extensively cultivated, and there seems no reason to doubt that
they originated as sports from a ribbon cane ; in no other way is it possible to
account for the terms White, Black, and Striped Cheribon; Transparent,
White and Purple Transparent ; Striped Bamboo, Rose Bamboo, and Purple
Bamboo ; and it must have been with full knowledge of their origin that these
names were given.

Assuming the identity of the Louzier with the Otaheite and Lahaiu£
canes, and remembering the origin of the former, it is also probable that the
latter originated in the same way, but having been introduced at early dates
as self-coloured canes no suspicion of their origin arose. This cane also is
known to throw a striped sport indistinguishable from the Mignonne from
which the Louzier arose, and this cane when planted separately throws self-
coloured sports, so that here a complete cycle through striped cane, self-coloured
cane, striped cane exists, though it is impossible to state which was the
original type ; perhaps the explanation of the phenomenon is to be found in
a cross-fertilization of the original cane.

37

CANE SUGAR.

It is important to note that when a striped cane throws sports two
varieties arise, one light -coloured and one dark-coloured, and that almost
always each light-coloured and each dark-coloured cane is identical ; thus, almost
every light-coloured sport from a striped Tanna cane is a white Tanna, and
almost every dark-coloured cane is a black Tanna.

Sporting from self-coloured canes is a less frequent phenomenon than from
striped canes, but evidence exists that some self-coloured canes throw two
distinct striped sports. When in Mauritius the writer understood that it was
a matter of common knowledge that the Louzier threw two distinct sports, one
a cane identical with the Mignonne, and another (described already) called the
Home cane after its first observer : both these canes are in Mauritius
indifferently known as Louzier rayee. The writer has also observed these
sports springing from the Otaheite cane under the name of Bourbon or Lahaina
in Demerara and in Hawaii.

Another instance of a striped cane springing from a self-coloured cane was
observed in the Hawaiian Islands by Mr. E. W. Broadbent, who found a green
rand yellow ribbon cane springing from the Yellow Caledonia (White Tanna).
In this case the sport was quite distinct from the Striped Tanna, the parent of
-the White Tanna.

In Mauritius the Port Mackay (Cavangerie) is known to give a black
•cane, the Port Mackay Noir, and the Striped Iscambine imported thither
from New Caledonia has given rise to several Iscambine canes, one of which is
-of merit.

Finally, in Hawaii, a cane — the Striped Tip — of uncertain origin, has
-afforded the Yellow Tip, also a cane of merit.

Seedling Canes. — Previous to 1885 it was generally believed that
the cane was infertile. This belief may perhaps be traced to the statement
made by Hughes in 1750, in The Natural History of Barbados ; the contrary
•statements of the eighteenth century travellers, Rumphius and Bruce, being
too vague to be of value. Notwithstanding the fruit of the cane had been
-accurately described by Dutrone in 1790, and figured in Porter's treatise
(1843). In 1859, Parris, in a letter in the Barbados Advocate, stated that he
had observed cane seedlings, a statement again confirmed, by Drumm in the
Barbados Agricultural Reporter in 1869, the letter announcing the observation
being copied in the Produce Markets' Review. In addition, about this time,
seedlings were tried on the large scale in Barbados, but, unfavourable characters
being developed, their cultivation was abandoned. At this same time the
Baron de Villa Franca in Brazil wrote as if the fertility of the cane was
without question, and was a fact of common knowledge. The rediscovery of
this very important fact was made independently, and nearly simultaneously,
by Soltwedel in Java, in 1888, and by Harrison and Bovell in Barbados, in
1889. Since then many valuable varieties have been raised. The pioneer and
chief workers in this field have been Went, Wakker, Kobus, Bouricius and

38

VARIETIES OF THE CANE.

Moquette in Java, Harrison, Bovell, Jenman, Hart and Lewton-Brain in the
British West Indies, the brothers Littee in Martinique, Boname and Perromat
in Mauritius, and Eckart in Hawaii; in addition, private enterprise is
exemplified by the raising of seedlings at the Diamond Plantation in Demerara,
and at the Hambledon Mill in Australia ; it has also been undertaken by many
planters in Barbados, in Mauritius, and in Brazil.

At first, in Java, this discovery was regarded as of academic interest only,
since it was believed that the Cheribon cane had reached commercial perfection,
and it was not till the appearance of the sereh disease that the propagation of
seedlings was undertaken with vigour ; a similar lack of incentive was never
present in the British West Indies, and the discovery was followed up by
Harrison and his colleagues from the first.

The factors governing the properties of seedling canes have been studied
in great detail by Harrison and Jenman26 and by Went and Prinsen
Geerligs27. Briefly it appears from their work that the cane is enor-
mously subject to variation and that there is but little tendency towards
the inheritance of the properties of either parent; in all cases where
successful seedlings have been obtained it has been by growing a very large
number of seedlings and eliminating almost all. Harrison has pursued this
method up to the extent of raising over 1,000,000 seedlings, the very
greater proportion of which were destroyed off hand ; of the remainder only a
few survived the first preliminary selection, and eventually these were cut
down to very small numbers. In Java, also, very large numbers have been
raised and have been rapidly weeded out at an early stage of growth.

It was observed at an early stage that the Cheribon cane in Java had no
fertile pollen whilst the ovaries of the flower were normal ; hence the plan of
growing in alternate rows a pollen-bearing variety and the Cheribon cane
arose ; most of the Javanese seedlings have been thus obtained. The most
prolific workers in Java have been Bouricius who used the Canne Morte, and
Kobus who used the Chunnee (an Indian variety), as the male parents. Else-
where the seedlings raised have generally been adventitious, the male parent
being uncertain.

In 1904 Lewton-Brain28 in Barbados and Mitchell29 in Queensland
emasculated cane flowers and fertilized them with pollen from another variety,
thus obtaining hybrids of certain parentage ; this method is now being
followed up, but the skill required and the small number of hybrids obtained,
and there being at present no reason for supposing that these hybrids will
develop superior qualities over adventitious seedlings, makes it doubtful if this
method is advisable. At the very least it can be said that very valuable canes
have resulted from the scheme of selection from a very large number of
seedlings, a method which is simplified by the observation that it is only the
outstanding canes of merit grown under experiment station conditions that
have any chance of success on the estate scale.

39

CANE SUGAR.

Of the seedling canes that have become prominent there may be
mentioned —

Demerara Canes. — Referred to under the initial D.

D. 74.— Stalk: Pale green, erect, stout, medium length of joint. Leaf:
Broad, light green. Arrows profusely and matures early.

D. 95. — Stalk : Dark purple, erect, average girth and length of joint.
Eye* : Prominent and inclined to sprout. Leaf; Light green, narrow, erect.
Arrows profusely and matures early.

. The above two canes are historical, as they were the two first sent out by
Harrison. In Demerara they have proved of no merit, but their habit of early
maturity has made them canes of value in Louisiana.

D. 78. — Stalk: Greenish red, erect. Leaf: Dark green. Arrows sparsely.

D. 109. — Stalk: Dark purple, erect. Leaf: Dark green, narrow. This
cane possesses in a marked degree the property of ' going back '—that is to
say, it is very atavistic — and in second and third ratoons degenerates into a
reed-like growth.

D. 145. — Stalk: Greenish purple, erect, stout, very brittle. Eyes:
prominent. Arrows sparsely.

D. 625. — Stalk: Erect, yellow, stout. Leaf: Light green. Eyes :
Small. One of the most successful of the Demerara canes.

D. 1135.— Stalk: Erect, red, of small girth. Leaf: Light green. Eyes:
Prominent. Yery large number of canes in a stool. This cane is not largely
grown in Demerara, but on introduction to Hawaii has shown signs of being
of great merit.

Barbados Canes. — Referred to by the initial B.

B. 109. — Stalk : Erect, yellowish green, stout, joints of average length.
Leaf: Dark green, separating easily from the stalk when dry. Arrows
sparsely.

B. 147. — Stalk: Yellow, recumbent, average girth and very long jointed,
with a well marked channel. Leaf: Broad, dark green, adherent. Arrows
sparsely.

This cane when first established received much ill-advised advertisement,
and though of great merit has consequently suffered by comparison.

B. 208. — Stalk: Erect, green, with peculiar swellings at many nodes.
Leaf: Yertical, dark green. Eye: Prominent, inclining to sprout. This cane
is extraordinarily subject to environment, in some places being of great merit
and in others valueless ; it is unsuited for heavy clays, is of great saccharine
strength and is reputed to be drought-resisting ; it is also subject to variation.

B. 306. — Stalk : Erect, yellow, long jointed. Leaf: Broad, dark green,
separating readily. Eye : Small. Arrows sparsely.

40

VARIETIES OF THE CANE.

Mauritius Canes.— Referred to by the initial M. The following
notes were collected during the writer's residence in this island where
systematized work has been absent.

M. 33. A green recumbent cane, with some peculiar abortive joints ;
medium girth, long internodes.

M. 53. A dark purple, medium-sized cane.
M. 80. A reddish-purple stout cane.

M. 131. A small upright purple cane, extremely prolific in number of
canes to a stool.

Java Canes. — Of the very many canes raised in Java, the most
prominent are described below; of these P.OJ. 100. is a cross between a
black Borneo cane and an unknown father; Bouricius 247 is a cross between
the Canne Morte or Red Fiji (male) and the Cheribon (female) ; these were
obtained by Wakker and Bouricius. The others were obtained by Kobus from
crossing Cheribon canes with Chunnee, and to him I am indebted for the
descriptions below.

S3 P.O.J*— (I.) Dark violet, brown red when older; (2.) Thick all
over the internodes ; (3.) Constricted ; (4.) Straight line ; (5.) Spherical, small,
not prominent; (6.) Invisible ; (7.) 2-3 ; (8.) White ; (9.) Green, pink where
sun-exposed; (10.) None; (11.) Green; (12.) Narrow, upright, not bending;
(13.) Strongly lobed at one side, slightly lobed at the other side ; (11.) An
upright, long, strong cane, does not arrow, immune to sereh.

86 P.OJ.— (1) Green; (2.) Fairly thick all over the internodes; (3.)
Somewhat constricted ; (4.) A straight line ; (5.) Cordiform ; (6.) Invisible ;
(7.) 2-3; (8.) White ; (9.) Green, pale pink where sun-exposed; (10.) None;
(11.) Green; (12.) Narrow, long, bending near top; (13.) Slightly lobed on
one side; (14.) A long hard and strong cane, arrows sparsely 2 and $
sterile ; immune to sereh.

100 P. O.J. — (1.) Golden to light brown with fiery red sunburnt patches ;
(2.) In a ring under the nodes ; (3.) Cylindrical; (4.) Faintly zigzag ; (5.) Oval
when young, somewhat swollen or prominent later ; (6.) Distinct on two-
thirds of the internodes; (7.) 3-4; (8.) White; (9.) Green, pink where
sun-exposed; (10.) Dense thick hairs on back and sides ; (11.) Yellowish-green;
(12.) Broad, not very long, bending near top ; (13.) Slightly lobed at one side ;
(14.) An upright, rather short cane, very sweet, ripens early, arrows
profusely, $ fertile, £ sterile, nearly immune to sereh.

*(1.) Colour ; (2.) Wax ; (3.) Shape of interuode ; (4.) Arrangement of internodes ; (5.) Shape
of eye ; (6.) Channel above eye ; (7.) Rows of roots ; (8.) Colour of pith ; (9.) Colour of leaf
sheath ; (10.) Pilosity of sheath ; (11.) Colour of leaf blade ; (12.) Shape of leaf blade ; (13.) At
junction of sheath aud blade, the former is ; (14.) General characters.

41

CANE SUGAR.

139 P.O.J. — (1.) Pink when young, dirty greenish pink when older;
(2.) Fairly thick all over the internodes; (3.) Cylindrical; (4.) Faintly zig-
zag; (5.) Small, spherical ; (6.) Distinct on two-thirds of the internodes ; (7.)
2-3; (8.) White; (9.) Green, pink where sun-exposed; (10.) None; (11.)
Green; (12.) Narrow, long, bending at top ; (13.) Lobed on one side ; (14.)
A short, upright cane, very sweet, ripens early, does not arrow, immune to
sereh.

161 P.O.J. — (1.) Pink when young, later yellowish green, mixed with
dirty pink; (2.) Thick all over the internodes ; (3.) Cylindrical; (4.) Faintly
zig-zag; (5.) Cordiform; (6.) Faintly visible over half the internodes; (7)
3-4; (8.) White; (9.) Green; (10.) None; (11.) Green; (12.) Long,
narrow, bending near top; (13) Lobed on one side; (14) A long, sweet,
upright cane, arrows sparsely, ? and <£ fertile, immune to sereh.

181 P.O.J.— (1) Yellowish red with sunburnt patches of dark red; (2.)
Fairly thick all over the internodes ; (3.) Somewhat constricted ; (4.) Faintly
zig-zag; (5.) Cordiform, somewhat pointed and prominent; (6.) Faintly
visible on half the internodes ; (7.) 3; (8.) White; (9.) Green; (10.) None;
(11.) Green; (12.) Very narrow, upright; (13.) Not lobed; (14) A long,
upright thin cane, arrows profusely, $ and $ fertile, immune to sereh.

218 P.O.J. — (1.) Bright violet red; (2.) In a ring under the nodes;
(3.) Cylindrical; (4.) A straight line; (5.) Oval, small; (6.) Distinct on
two-thirds of the internodes; (7.) 3; (8.) White; (9.) Green, dark pink
where sun-exposed; (10.) None; (11.) Green; (12.) Bending at top ; (13.)
Not lobed ; (14.) A long upright thinnish cane, tillering profusely, very sweet,
arrows profusely, ? fertile, $ sterile, immune to sereh.

P.O.J. — (i.) Violet red when young, later a dirty brown; (2.)
Fairly thick all over the internodes; (3.) Constricted ; (4.) A straight line ;
(5.) Cordiform broad ; (6.) Faintly visible on half the internodes ; (7.) 3-4;
(8.) White; (9.) Green, pale pink where sun-exposed ; (10.) None; (11.)
Green; (12.) Narrow, long, bending at top; (13.) Strongly lobed at one
side; (14.) Tillers profusely, very sweet, arrows moderately. ? fertile,
<$ sterile, immune to sereh.

247 Souricim.—(l.'} Dark violet red; (2.) Fairly thick all over the
internodes; (3.) Cylindrical; (4.) Distinctly zig-zag; (5.) Cordiform; (6.)
Invisible; (7.) 3-4; (8) White; (9.) Green, dark violet where sun-exposed ;
(10.) Some stiff hairs on back; (11.) Dark green with a violet tint; (12.)
Broad and long bending at top ; (13.) Not lobed ; (14.) An upright, long and
thick cane, sweet juice, ripens late, arrows occasionally. $ and <$ fertile,
liable to sereh.

42

VARIETIES OF THE CANE.

Home of the Sugar Cane.— The place whence the cane was
introduced has been the subject of speculation and controversy, India and the
South Pacific being the places most in dispute. In 1891 Kobus18 remarked on
the differences between the Ukh canes of India and those cultivated in Java ;
this difference is apparent from Hadi's description of the former, and is so
pronounced that it seems fair to suggest that the cultivated varieties of
cane (elsewhere than in India) and the Ukh canes are not merely varieties
but distinct species.

Of the varieties cultivated elsewhere than in India it is certain that the
Otaheite cane (or canes), the Tanna canes, the Cavengerie cane, and the
Escambine canes are indigenous to the South Pacific; the Cheribon canes
have certainly been known in Java for generations, but the writer has never
found any authoritative statement that they are the indigenous. The literature
of the cane shows, too, that these Cheribon canes have also been known in the
South Pacific from early times, and even the name ' Otaheite ' is in some
places (cp. supra) attached to these canes. In addition, the writer has been
authoritatively informed that canes of the Cheribon type were known in India
as Otaheite canes at the end of the eighteenth century. There seems, then,
much reason to suppose that the Cheribon canes are not indigenous to Java, but
originated from the South Pacific ; if, as seems reasonable, this speculation
connecting these canes with the South Pacific is correct, then all the standard
cultivated varieties of cane originated in the South Pacific, that is to say east
of Wallace's line, and they form, at the very least, a type of cane very far
removed from those found to the West.

The statement that the 'Bourbon' cane came to that island from the
Malabar coast is often found ; the original statement the writer has never been
able to trace, and at the most the statement only implies that the vessel that
brought the stock to Bourbon cleared from that locality.

The evidence that the sugar cane is indigenous to the New World seems
quite unsatisfactory.

REFERENCES IN CHAPTER IV.

1. 8. (7., 220.

2. Stubbs' Sugar Cane, p. 66.

3. 8. C., 273.

4. Formen und Farben Saccharum officinarum.

5. Bull. 26, Agric. H.S.P.A.

6. The Practical Sugar Planter, pp. 1-18.

7. Das ZucJcerrohr, p. 124.

43

CANE SUGAR.

8. Bull. Assoc. Abs., October, 1907.

9. W. I. B., YIIL, 1.

10. The Sugar Journal, August, 1895.

11. Sugar, XII., 1.

12. Le Canne d Sucre, pp. 14-18.

13. 8. C., 337.

14. 8. 0., 124.

15. Nature and Properties of the Sugar Cane, p. 218.

16. 8. C., 206.

17. The Sugar Industry of the United Provinces of Agra and Oude, pp. 3-36.

18. Dictionary of the Economic Products of India, pp. 938-942.

19. Report Bur. Exp. Stat., Queensland, 1907.

20. Quoted in Simmond's Tropical Agriculturist.

21. Thrumm's Hawaiian Annual, 1882.

22. Eelatorio apresentado a Sociedad Paulista de Agricultura. S. Paulo, 1905.

23. 8. C., 17.

24. S. C., 64.

25. W. L. B., II., 4.

26. 8. C., 336, 337.

27. 8. C., 310, 311, 321, 322, 323.

28. W. L B., IV., 6.

29. Report of Queensland Acclimatization Society, 1905.

44

CHAPTER V.

SUGAR CANE SOILS.

The cane is a plant which in its economy demands large quantities of
water, and hence when grown under natural conditions it requires a soil of
considerable water-retaining power. Such a soil is represented by a typical
clay, and such soils under profitable cane cultivation are to be found in British
Guiana, Louisiana, and in other countries.

Following on clays, loams and alluvial deposits, containing large quantities
of humus which also belong to the water-retaining type, are suited for cane
cultivation. Not less important than a high retentive power for water is the
necessity for the removal of an excess of water ; a clay soil standing on a
porous substratum is for this reason much more suitable than one where the
under-drainage is less complete. Where ample water is available for irrigation
lighter soils of no great water holding capacity give, with intensive fertilization,
enormous yields ; the estates in Hawaii which have become notorious for their
high returns are of this class, and yields but little inferior are obtained in Peru
from very light sandy soils.

These last soils under natural conditions are quite unsuited for cane
cultivation ; in such soils, unless under artificial irrigation, a small cane with a
high fibre content is obtained. In soils where the moisture content is too high,
whether due to excessive rainfall or to insufficient drainage, the maturity of
the cane is delayed, and a product with but a low percentage of sugar is obtained.

Delteil1 makes the following statement with regard to cane soils : —

" In mellow open soils, watered by rain or irrigation, the cane becomes fine
and large and gives much sugar. In light sandy soils, or in volcanic soils of recent
origin, the juice is very sweet, but the canes are somewhat small.

" In calcareous soils, the canes develop superlatively well, the juice is rich and
easy to work. In alluvial soils, too moist or too rich in alkalis, the canes have
a fine appearance, but the juices are poor in sugar, work with difficulty and produce
much molasses."

Boname2 makes the following pertinent observations on cane soils and

climate : —

" The cane grows more or less well in all soils if it receives the care and
manures that its economy demands ; but, to develop vigorously, and to supply a
juice rich in sugar, it demands a free and deep soil. The physical properties of the
soil are at least as important as its chemical composition, and if irrigation is
impossible during the dry season its coolness will naturally be one of the principal
factors in the production.

"The most favourable nature of soil varies with the climate.

45

CANE SUGAR.

" Where rain is abundant the soil should be light and porous ; if rains are
scanty a too light soil will dry rapidly, and vegetation will be checked ; the cane
will not completely die, but in place of giving large stalks, rich in sugar, it will
produce small, dry, hard and woody stalks. With a relatively dry climate a heavy
soil will give good returns if the rains are evenly distributed.

" With a rainfall of 5 to 6 metres (197 to 236 inches) a sandy soil, draining
easily, will give an abundant return with a high consumption of manure. A clay
soil, especially if it is situated on a plain, will be constantly saturated with stagnant
water, which will prevent the aeration of the soil ; canes will develop feebly, and
their roots will rot little by little, leading to the death of the stalk.

" Some alluvial earths produce a luxuriant vegetation in wet years. The
canes are very fine, but very watery.

" Other things being equal, a calcareous clay soil not excessively light will
give sweeter canes than a clay containing vegetable debris, but the yield will
generally be less abundant. If the rains are sufficient and conveniently divided,
returns both for the cultivator and for the manufacturer will be excellent. If the
season is wet the advantage will remain with the lighter soils, whilst if it is dry
the canes will suffer much and will afford stunted and woody stalks.

" High and almost constant results will be obtained with irrigation and porous
soils ; for the growth can be regulated at will, and conducted in a fashion so as to
obtain the maximum cultural and industrial return, promoting the size of the cane
and its leaf development in the first stages of its growth and without intermission,
until the time arrives when it is necessary to develop the juices formed at an
early stage."

Reynoso3 says : —

<c Experience has shown that lime is a necessary element in the constitution of
soils most appropriate to the cane ; in calcareous soils not only are the most robust
canes grown, but these also afford juices richest in sugar from which is easily
extracted the desired product. These soils are both of 'great return and very
sacchariferous,' but it must not be forgotten that lime is but one element which,
associated with others, forms good soils."

The nature of the soil has a profound and imperfectly understood effect
on the sugar cane, considered in its varietal aspect ; a variety which succeeds
on, say, a heavy clay may be a failure on a sandy soil. This point has been
very prominent in connection with the new seedling varieties, so much so that
the success of a seedling on one type of soil is no evidence that it will be
successful on another, even when climatic conditions are little changed ; the
seedling B. 208 is a case in point.

Special Points in regard to Cane Soils.— The cane has
been accused of being a haliophile plant, and in certain districts, such as
British Guiana, and the Straits Settlements, it is grown in soils containing a
notable proportion of salt ; this point is reflected in some analyses of the cane
ash collected in a subsequent Chapter, some of which show large percentages
of sodium chloride. This point has been very thoroughly discussed by
Geerligs,4 whose results show that while the cane can grow normally on such
soils, it is in no way benefited, and cannot be considered as haliophilous.

Du Beaufret5 states that in French Guiana cane soils are renovated by
periodic floodings with sea water.

46

SUGAR CANE SOILS.

Hawaiian Soils.— The soils of the Hawaiian Archipelago have been
examined in great detail by Maxwell6 and by Eckart and to a less extent by
Crawley, by Shorey, and by Hilgard;7 in view of the exceptionally high
returns obtained in this district the study of these soils is of especial interest.

The soils of the Hawaiian Islands have been formed by the decomposition
of black basaltic lavas containing very large quantities of iron and lime, but
much smaller quantities of potash ; these basalts also contain considerable
quantities of phosphates in the form of apatite.

Maxwell classifies the Hawaiian soils as follows : —

A.— GEOLOGICAL FORMATION.

1 . Dark Red Soils.— Soils formed by the simple weathering of normal lavas,
in climatic conditions of great heat and dryness.

2. Yellow and Light Red Soils.— Soils derived from lavas that underwent
great alteration, under the action of steam and sulphurous vapours, at the time of,
or after, emission from the craters.

3. Sedimentary Soils. — Soils derived from the decomposition of lavas at
higher altitude?, and removal and deposition by rainfall at lower levels.

B.— CLIMATIC CLASSIFICATION.

1. Upland Soils. — Soils formed under lower temperatures and greater rainfall,
and distinguished by a large content of organic matter and nitrogen, and by a low
content of the elements of plant food in an available state ; these elements having
been removed by rainfall.

2. Lowland Soils. — Soils formed under a high temperature and less rainfall,
and characterized by a lower content of organic matter and nitrogen, and by a
higher content of the elements of plant food in a state of immediate availability ;
which is due in part to the receipt of some soluble constituents from the upper
lands, and to a smaller rainfall over the lower levels.

It is on the dark red soils and on the sedimentary soils that the high
yields of cane in this district are produced. These sedimentary soils are often
of great depth, reaching to as much as 30 feet, and form the soil of the most
productive areas in the group of islands.

The colour of the yellow soils is due to ferrous salts, and it is to the
presence of these bodies that Maxwell attributes the smaller productiveness of
these soils. (The yellow colour of the clay known in Dernerara as * Yellow
Mary,' the obnoxious nature of which is well known, is also due to ferrous
salts.)

The soils of Hawaii are all ' basic ' in character, and are consequently
marked by a low proportion of silica, in contradistinction to soils as clays of
an ' acidic ' nature which consist very largely of silica. The quantity of iron
in Hawaiian soils is very remarkable, the percentage of ferric oxide reaching
to as much as 30 per cent.

As a general rule the soils are * light ' and easily worked, and in
every way fitted for the production of enormous crops. The following figures

47

CANE SUGAR.

give the mean composition of the soils of the Hawaiian Islands based on 397
analyses, by the American (United States) official method* : —

Phosphoric

Lime. Potash. Acid. Nitrogen.

Island. Per cent. Per cent. Per cent. Per cent.

Oahu '411 .. '348 .. '269 .. '119

Kauai '504 . . '358 . . '237 . . '246

Maui .. -691 .. "401 .. '200 .. '222

Hawaii '833 .. '353 .. '321 .. '388

Whole Group . . . . '693 . . '366 . . -268 . . -290

Maxwell also determined the solubility in 1 per cent, of citric acid, of
lime, potash and phosphoric acid in a number of typical soils. The averages of

his results (calculated by the present writer) are as below : —

Phosphoric

Lime. Potash. Acid.

Per cent. Per cent. Per cent.

Highest -281 .. -084 .. -0125

Lowest '030 .. '009 .. '0012

Average '113 .. '033 .. -0043

The low amount of available phosphoric acid in proportion to the great
amount actually present is due to the accompanying ferric oxide, which is
present in very great amount. Hilgard, in examining Hawaiian soils, calls
attention, too, to the high content of phosphoric acid — " exceeding all others
on record," and, at the same time, emphasizes the action of ferric oxide in
rendering the phosphoric acid unavailable.

Other Hawaiian soils examined by him, while containing large amounts
of nitrogen, were yet ' nitrogen hungry.' The percentage of nitrogen in the
humus of these soils was low, and Hilgard is inclined to attribute more
importance to the nitrogen in the humus than to the total nitrogen. Mr. C.
F. Eckart, however, has pointed out to me that a very large proportion of the
soils of the Hawaiian Islands is acid ; and hence they are not in a condition
suited for nitrate formation without some previous treatment.

British. Guiana Soils. — The soils of this Colony have been critically
examined by Harrison8. He distinguishes eight types of soil, of which only
three occur within the part where the cane is cultivated. These three are : —

1 . The clay soils of the alluvial coast lands.

2. The sand reef soils of the alluvial coast lands.

3. The peaty or ' pegass' soils of the alluvial coast lands.

Of these soils he writes : —

"Experience has indicated to us that in Class I. we find soils of marked
fertility : soils which, with careful cultivation and tillage, should not alone retain
their fertility for long periods, but give gradually increasing leturns. These are
the sugar cane and rice lands of the colony.

* These averages have been given me through the courtesy of Mr. C. F. Eckart.

48

I

FIG. 11.

PURPLE

BAMBOO.

PLATE III

SUGAR CANE SOILS.

" In Class II. we have the soils which are not infrequently met with in "belts
known as sand reefs crossing sugar estates. They are to a great extent practically
useless for economic cultivation.

" Class III. consists of soils frequently characteristic of parts of the sugar
estatas, and of which much of the swamps and wet Savannahs of the back parts of
the illuvial coast lands consists. They also are found very commonly at short
distances back from the banks of the lower parts of our rivers and creeks. As
indicated earlier in this report, they are essentially peat soils, and as such are
unsatisfactory and difficult to work. But given tillage, drainage, and amelioration
of their texture by admixture with the underlying clays, they offer mines of wealth
of plant food for future agriculturists in this colony."

Harrison states that —

"The alluvial soils of British Guiana are largely derived from seaborne mud
from the Amazon river, and are not delta soils of the Guianan rivers."

The mean composition of the coast soils included in Class I. he gives as —

Per cent.
Nitrogen -209

Lime -212

Potash -425

Phosphoric Acid . . -072

Soluble in 20 per cent, hydrochloric
acid at the temperature of boiling
water over five working days.

A tract of virgin savannah land, situated six miles west of the Berbice
river and four miles from the coast, was found by the writer to be of the

following average composition : —

Soluble in

Total quantities 1 per cent,

per cent.* on citric acid

air dry soil. with 5 hours'

continual shaking.

Lime -153 .... '0312

Magnesia -539 . . . -2635

Potash 1-467 .... '0162

Phosphoric Acid -093 '0034

Humus 6-013

Nitrogen -479

The soil was a tenacious grey clay underlying a layer of ' pegass ' from
three to six inches deep, and was sampled to a depth of one foot.

Egyptian Soils. — The Egyptian soils upon which the cane is culti-
vated are in Upper Egypt, and lie in a narrow strip on both banks of the Nile ;
the soil is all an alluvial deposit of great depth, overlying a basis of sand, and
has been formed, and is continually renewed, by the overflow of the Nile.
Numerous analyses have been made of these soils, many of which have been
collected by Pellet and Roche.9 They remark : —

"The soil of this district is very uniform in its general composition; the
percentage of calcium carbonate is from 5 to 7, of sand from 20 to 60, of clay from
20 to 60, of humus -8 to 1-3.

" The very compact nature of the greater part of the soils attracts attention,
and certainly influences to a greater or less extent the availability of the fertilizing
elements.

" Very remarkable is the presence, rare in arable soils, of a large quantity of
magnesia, from 1 per cent, to 3 per cent.

* Determined by decomposition with sulphuric acid and ammonium fluoride.

49

CANE SUGAR.

" The fertilizing elements, properly so called, were found per kilogram : —

Phosphoric acid 1-44 to 2-30, mean, 1*75 grms.

Potash 1-56 to 3-68, ,, 2-28 „

Organic nitrogen -37 to 1-40, ,, -72 ,,

Nitric nitrogen, trace to .. — '040, ,, *004 ,,
" Finally, the quantities of chlorine and sulphuric acid which have so great an

influence on the formation of efflorescent salts injurious to vegetation were found in

healthy soils.

Chlorine .. -10 to -06 per 1000.

Sulphuric acid -25 to 1-60 per 1000."

The average composition of 28 samples of sugar cane soils is thus given
by these authors : —

True density

2-23

Potash

•228

Apparent density . .

1-15

Lime

2-49

Moisture

6-30

Magnesia

2-87

Chalk

6-40

Iron and Alumina

10-52

Sand

45-80

Manganese

•084

Clay

36-40

Organic nitrogen

•072

Humus

1-17*

Nitric nitrogen

•0004

Phosphoric acid

•175

Chlorine

•005

Sulphuric acid .

•073

* Scliloesing's method.

The quantities given are the percentages soluble in nitric acid, according
to the official French method.

The mean of seven analyses of Egyptian soils made by Mackenzie and
Burns10 with hydrochloric acid as solvent gave the following results : —

Phosphoric acid
Potash . .
Lime

Iron and Alumina..

•246
•615
•418
•270
22-15

Manganese
Chlorine

Organic nitrogen
Nitric nitrogen .

•26
•064
•082
•0018

Louisiana Soils. — Stubbs11 thus summarizes the sugar soils of
Louisiana : —

Our soils, then, of the sugar belt lying along the Mississippi River and its
numerous bayous, may be considered as varying from silty loams to very stiff clays.

There are also the red and brown lands, varying from sandy loams to loamy
clays of the Red River and its outlying bayous, the Teche, the Boeuf, the
Cocodrie and Robert, which have been formed by a similar process by the Red
River, though drawn from a much more restricted area of country.

The prairie lands west of Franklin, varying in character from black stiff clays
to silty loams, are our bluff lands second hand, which have been removed from the
western bank of the Mississippi River and spread out over the marshes of south-
western Louisiana. These bluff lands occur in situ on the eastern bank, running
continuously from Baton Rouge to Yicksburg, giving us several parishes in which
sugar cane is grown. These are usually silty loams, and are also of alluvial origin,
though antedating the present Mississippi River. The bluff and prairie lands, and
the alluvial deposits of the Red and Mississippi Rivers and their bayous, give the
soils upon which the sugar cane of Louisiana is grown.

As the result of many samples Stubbs gives the following average.
Contents of the soils in the sugar belt : Lime, '5 per cent. ; potash, '4 per
cent.; phosphoric acid, •! per cent. ; nitrogen, *1 per cent.

50

SUGAR CANE SOILS.

Peruvian Soils. — The following account of Peruvian soils is
abridged from Sedgwick.12

The cane area of Peru lies on the western slope of the Andes, between that
range of mountains and the sea, the latitude of the largest district being 7° S.
The cultivated areas lie in valleys of a very gentle slope seawards, the
drainage notwithstanding being excellent. The depth of the soil is from two-
to twenty feet, and it varies in character from a fine sandy loam to silt.

The soils are of the alkali type, and especially towards the sea contain1
considerable quantities of water-soluble chlorides, sulphates and carbonates.

The soils are well supplied with plant food, the lime, much of which is
present as carbonate, being very high compared with that found in the cane
soils of other districts ; the total phosphoric acid and potash are also good ; the
nitrogen is very variable, dependent upon the time the soil has been in
cultivation, the water supply, the class of weeds, and the amount of flood
waters required to cover the fields.

The humus and organic matter are both higher than would be expected in
the soils of an arid district.

Sedgwick gives thirty analyses of soils from the Cartavio estates, from
which the present writer has calculated the averages. The analyses are
presumably made by the official American method.

Maximum. Minimum.

Mean.

Insoluble matter

Alumina

Lime

Magnesia

Potash

Phospho

Sulphur:

Humus .

. 79-50 . 49-22 .. 63-71

xide
i

8-10 ..
7-50

4-00 . .
1-59

5-38

4-78

6-75 . .

•65 ..

2-98

a
ric acid . . . ....

2-57 ..

•60 ..
•43 . .

•23 ..
•16 ..
•16 ..

•92
•33
•24

ic acid . . ....

•88 ..

•05 ..

•18

1-84 ..

•42 . .

1-26

sol. in 1 per cent, citric acid . .
id sol. in 1 per cent, citric acid. .

•0258. .
•0630..

•0050..
•0081 . .

•0121
•0337

It is interesting to compare these soils with the equally productive ones of
the Hawaiian Islands. These soils are 'acidic,' and contain much more
silicates insoluble in hydrochloric acid than do the 'basic' soils of Hawaii,
the latter containing much more ferric oxide, and it is as a consequence of
this that the availability of the phosphoric acid in the Hawaiian soils is so-
much less than in the Peruvian. The high content of the Peruvian soils in
lime is, too, a factor which should contribute to their continued fertility.

51

CANE SUGAR.

Cuban Soils.— The soils of Cuba upon which the cane is grown are
divided by F. S. Earle13 into three classes, and are thus described by him : —

The Red Lands. — These are found mainly in Havana and Matanzas Provinces,
but they occur also in eastern Pinar del Rio and in certain areas near the coast in
the three eastern provinces. This red soil has many peculiar qualities. It is very
sticky when wet and is heavy and difficult to cultivate, and yet it allows water to
pass through it as readily as through the lightest sand. Within a few hours after
a heavy shower, if the sun shines, the surface will "begin to dry, and it will be
possible to run ploughs and cultivators. There is no subsoil, as the red surface soil
extends down practically unchanged to the bed rock, which is always a cavernous
limestone pierced with numerous subterranean passages which provide a perfect
natural under-drainage. There are very few streams or rivers in the red lands, as
the rain water sinks so readily into the soil and is carried off by these underground
passages, finally finding a vent in great springs, many of which come out in the
bottom of the sea, forming the spots of fresh water which are known to occur along
certain parts of the Cuban coast. This remarkable natural drainage makes these
soils easy to cultivate during the rainy season, but for the same reason they become
too dry for most crops during the winter, except where artificially watered.
Irrigation on a large scale will always be difficult on these lands, on account of lack
of available streams, and because so much water will soak away in the canals and
ditches that a large head will be required in order to cover a comparatively small
area,.

Taking everything into consideration, these lands are probably the most satis-
factory on the island for sugar production. With good management and with
favourable seasons the best black lands will yield somewhat heavier crops ; and it is
claimed by some that the cane from black lands is somewhat richer in sucrose ; but
the crop on the red lands is always certain ; never being injured by excessive rains,
and it is always possible to give sufficiently frequent tillage to keep down the weeds.
The cultivation is cheaper also, as no expensive drainage ditches are needed, and no
ridging up of the rows is required, level culture being best for these lands. The
red soil is well supplied with the mineral elements of fertility, and, on account of
its depth, it stands successive cropping for many years. No soils respond better to
the use of fertilizers, and none can be built up more quickly by the growth of
leguminous crops for green manuring.

Black Soils with a White Calcareous Subsoil. — These occupy large areas in the hill
regions in the northern and central parts of Havana and Matanzas Provinces.
Similar soils occur also in the eastern provinces, usually where the country is more
or less rolling. "When first cleared such lands are very fertile, but their hilly
character subjects them to constant loss from washing during heavy rains. Their
durability depends upon the original thickness of the top soil, and on the steepness
of the hills and the consequent degree of loss from washing. These soils are fairly
permeable to water, but not nearly so much so as the red soils. On account of their
more retentive character they cannot be cultivated so quickly after rains, nor, on
the other hand, do they suffer so quickly from drought during the dry season.
Ditching is seldom necessary except sometimes on the lower portions; the uneven
surface usually affords drainage, and it can be aided by slightly ridging up the rows
during cultivation. On the steeper and more broken of these lands, much of the
loss from washing could be avoided by terracing or running the rows in irregular
circles following the contour lines, as is done so universally in cotton fields on the
broken hill lands of the Southern United States. These irregular, crooked rows
seem unsightly and awkward to those who are not accustomed to them, but when
properly laid out they are very effective in preventing loss from washing.

Black Lands with impervious Clay Subsoil.— The black lands that are underlaid
with a stiff impervious clay present some of the most difficult problems to the sugar
planter. They are naturally very fertile, and, when conditions are favourable, they
yield maximum crops. But most of these lands are quite level, and the subsoil

52

SUGAR CANE SOILS.

holds the rainfall, so that the cane often suffers from a lack of drainage. In wet
seasons, too, it is difficult, or often impossible, to give sufficiently frequent cultiva-
tions to keep down the weeds. These troubles are not so obvious when the land is
new, as the immense number of decaying roots leave the soil more or less open and
porous, so that the surface water passes away more readily. With age the soil
settles together and becomes more compact and impermeable. All old lands of this
class will be greatly improved by establishing a carefully planned system of
drainage ditches and keeping them always well cleaned. Ridging up in cultivation,
so as to leave deep water furrows between the rows, will also be very advantageous.

Queensland Soils.— The sugar cane soils of Queensland have been
subjected to survey by Maxwell14. He divides the soils of Queensland into
three districts, the Southern or Bundaberg, the Central or Mackay, and the
Northern or Cairns.

Dr. Maxwell subdivides the soils of the southern district into four classes ;
the red soils, derived from true basaltic lavas ; the mixed dark and light red
and yellow red soils, derived partly from basaltic lavas and partly from
eruptive action upon other rock formations; soils more ratber than less of
sedimentary origin, and soils derived exclusively from older rock formations.

The Mackay soils are of an acidic type formed from the decay of mixed
siliceous rocks, and are in sharp distinction to those of the Bundaberg district.

The average analysis of the soils from the Mackay and Cairns district is
thus found by Maxwell : —

Phosphoric Phosphoric

Lime. Potash. Acid. Nitrogen. Lime. Potash. Acid.

Per Per Per Per Per Per Per

cent. cent. cent. cent. cent. cent. cent.

Total. Total. Total. Total. Available.*Available.*Available.*

Cairns .. '292 .. -310 .. -141 .. -122 .. -0654 .. -0132 .. -0010

Mackay.. -829 .. -223 .. -165 .. -122 .. -1119 .. -0222 .. -0020

Java Soils. — De Meijier15 states that the soils of Java are formed
from the decomposition of the volcanic rock (andesite) forming the mountain
ranges of Java : the resulting soils are clays, those of West Java being
generally very heavy and compact and requiring considerable moistening before
ploughing. In East Java there is evidence of the products of vulcanism — the
soils are lighter and sometimes more fertile. The native term Tanah ladoe is
applied to a mixed clay and sand soil, and Tanah lindjad to a heavy clay.

The soils of Java have, of course, been subjected to rigid examination j
the analyses published by Kramers16 are the most complete. The mean of
thirty analyses of East Java soils by him gives: — lime T9 per cent.;
magnesia *2 per cent.; potash *07 per cent.; phosphoric acid *06 per cent.;
nitrogen *07 per cent. A number of soils from West Java16 give as an average
lime *7 per cent.; magnesia *06 per cent.; potash '06 per cent.; phosphoric
acid '06 per cent.

Mechanical analyses of the soil show from 10 per cent, to 30 per cent, of
fine sand less than *5 mm., and from 50 per cent, to 90 per cent, of clay.

* Aspartic Acid Method.
53

CANE SUGAR.

REFERENCES IN CHAPTER V.

1. Le Canne a Sucre, p. 38.

2. Cultur de la Canne d Sucre, p. 33.

3. Ensayo sobre el cultivo de la canne de azucar.

4. I. S. J., 84.

5. Bull. Assoc., 1899, p. 1186.

6. Bull. 1A Agric. H.S.P.A.

7. Soils, pp. 297, 356.

8. Report, Brit. Guiana Gov. Lai., 1903.

9. Bull. Assoc., xxiv., p. 1691.

10. Khed. Agric. Soc. Jour.

11. Sugar Cane, p. 49.

12. On the Sugar Industry of Peru. Trujillo, 1905.

13. Bull. 2, Est. Cent. Agron. Cuba.

14. Reports, Bur. Sug. Exp. Sta., 1902-05.

15. Proc. Am. Soc. Civ. Eng., 54, 34.

16. Quoted in Kriiger's Das Zuckerrohr.

CHAPTER VI.
THE MANURING OF THE CANE/-*

The cane, in common with other economic plants, has received extensive
manurial trials ; from the many published statements available certain of the
results are abstracted below, arranged under the districts in which they were
made.

British Guiana. — Scard1, as the result of an extended series of experi-
ments on the Colonial Company's Estates in British Guiana, concluded : —

1. That lime used by itself gave a small pecuniary gain.

2. That lime associated with manures gives an increase sufficient to pay
for itself only when used with larger (2 cwt.) quantities of soluble nitrogen,
such as sulphate of ammonia.

3. That of nitrogenous manures, sulphate of ammonia at the rate of
2 cwt. per acre gives the best results.

4. That ground mineral phosphate appears to give an increased yield
compared with superphosphate.

5. That guanos, especially in conjunction with lime, fall far short of
ammonia in beneficial effect.

6. That an increase of phosphoric acid over the minimum employed
(168 Ibs. per acre) fails to give satisfactory pecuniary results.

7. That neither lime nor manures produce any perceptible difference in
the purity of the juice but only affect the weight of cane.

Harrison2 concluded as a resume of work on cane manuring : —

1 . That the weight of cane is governed by the amount of readily available
nitrogen either naturally present or added as manure.

2. When applied in quantities containing not more than 40 to 50 Ibs
nitrogen per acre, sulphate of ammonia and nitrate of soda are equally
effective manures on the majority of soils, but that when the unit of nitrogen
is of equal money value it is more economical to supply the former. Dried
blood and similar organic manures in which the nitrogen only slowly becomes
available are distinctly inferior sources.

3. Under ordinary conditions of soil and climate and the usual range of
prices for sugar, it is not advisable to supply more than 2 cwt. of sulphate of
ammonia or 2| cwt. of nitrate of soda per acre.

4. If circumstances arise in which it is desirable to obtain the maximum
yield per acre by the application of more than 50 Ibs. nitrogen per acre,
sulphate of ammonia should always be used.

* I write Manuring in preference to Fertilization, the term used in the United States, for by the
latter is properly understood the process of impregnating the female organs of the cane flower.

55

CANE SUGAR.

5. Practically on all soils manurings with nitrogen require to be
supplemented by phosphoric acid. The most effective form appears to be
superphosphate of lime and slag phosphate meal. Mineral phosphates are of
distinctly lower Talue and are not effective unless applied in quantities far
exceeding in value those required for either superphosphate or slag phosphate
meal ; as a rule phosphates should only be applied to plant cane, their action
on ratoons being limited.

6. On some soils the application of potash salts in quantities from. 60 to
160 Ibs. sulphate of potash per acre results in greatly increasing the effectiveness
of nitrogenous manuring. Soils containing less than '01 per cent, potash soluble
in 1 per cent, citric acid will as a rule respond favourably to this treatment,
while those containing between *01 per cent, and '02 per cent, may or may not
be favourably affected.

Harrison3 has also given a resume of the results obtained from twenty-
four years' experimental work in British Guiana. A short abstract of these
results is given below :

Lime. — Alternate beds of heavy clay land were treated with five tons of
slaked Barbados lime per acre. The canes were grown up to third ratoons and
then fallowed for a year. In the plots which were manured in addition to
liming, the total increase due to liming was 37'0 tons of cane per acre, and in
the unmanured plots at the rate of 33-7 tons per acre. Both the above
increases refer to the sum total of ten crops harvested in 13 years.

Phosphates. — Applications of phosphates have not always resulted in
financial benefit. It appears that the most satisfactory mode of using phos-
phates is to apply 3 cwt. of superphosphate or 5—6 cwt. of slag phosphate to
plant canes, the dressings of slag phosphate being more remunerative than
those of superphosphate of equal cost. Phosphates do not benefit ratoons and
Prof. Harrison thinks it doubtful if it is necessary to apply phosphates to
Demerara soils as often as once in five years.

Potash. — Results obtained with both sulphate and nitrate of potash
indicate that potash is not required on the heavy clay soils of British Guiana
under the conditions of ordinary agricultural practice.

Nitrogen. — As the mean result of ten crops of cane in 13 years it was
found that 10 Ibs. of nitrogen as sulphate of ammonia, when added in pro-
portions up to 300 Ibs. per acre, gave an extra return of 1-3 tons of cane per
acre, or 2£ cwt. commercial sugar. With nitrate of soda up to 250 Ibs. per
acre, 10 Ibs. of nitrogen would probably give 1*4 tons of cane, equal to 2£ cwt.
of commercial sugar, but experiments indicate that it is not wise to apply
more than 250 Ibs. nitrate of soda at one dressing. With dried blood the
indications over eight crops were that the relative value of nitrogen in this
material was 73 per cent, of that in sulphate of ammonia.

56

THE MANURING OF THE CANE.

"With regard to the effect of manures on the soil, Prof. Harrison comes to
the following conclusions, basing his results on the analytical figures obtained
by the extraction of the soil in 1 per cent, aqueous citric acid with five hours'
continuous shaking: —

1. That the growth of the sugar cane without nitrogenous manuring
is accompanied by a considerable loss of the nitrogen in the soil, amounting in
ten years to 18'6 per cent, on not limed land, and to 26*7 per cent, on limed
land. These are equivalent to losses from the soil to a depth of eight inches
of 880 Ibs. and 1250 Ibs., respectively, per acre.

2. Repeated heavy dressings with farmyard manure have resulted in
an increase in the total nitrogen of the soil. In ten years the increase was
20-3 per cent., equal to 960 Ibs. of nitrogen per acre added to the soil to a
depth of eight inches.

3. The growth of the sugar cane on plots receiving only nitrogenous
manures has resulted in losses of soil nitrogen : where sulphate of ammonia
was applied, the loss amounted to 147 percent., or to 670 Ibs. of nitrogen,
and where nitrate of soda was used, to 16'3 per cent., or to 775 Ibs. of
nitrogen per acre, in the soil to a depth of eight inches.

4. On soils manured with phosphates, potash, and nitrogen in the form
of sulphate of ammonia, the loss of soil nitrogen in the top eight inches
amounted to 14*7 per cent., or to 700 Ibs. per acre, while where nitrate of
soda was the source of nitrogen the loss was far higher, amounting to 26-5 per
cent., or to 1250 Ibs. per acre.

5. The soil in 1891, at the commencement of the experiments, yielded
•0142 per cent, of phosphoric anhydride to a 1 per cent, aqueous solution of
citric acid. After ten years' cropping without manure it yielded '0086, which
shows a loss of nearly 40 per cent, of the probably available phosphoric
anhydride, or of, in round figures, 170 Ibs. per acre.

6. Where the soil received manures not containing phosphates, the
proportion of probably available phosphoric anhydride was reduced to -0096
per cent., equal to a loss of 32*4 per cent., or to one of, in round figures,
140 Ibs. per acre.

7. Where superphosphates were used in addition to nitrogenous manures,
the proportion of probably available phosphoric anhydride was reduced to
0-132 per cent., indicating a loss of 7 per cent., or of 30 Ibs. per acre.

8. Where slag-phosphates had been applied, the probably available
phosphoric anhydride has been reduced to '0102 per cent., equal to a loss of
28*1 per cent., or to one of 120 Ibs. per acre. It is worthy of note that in
our more recent experiments, while manuring with slag-phosphates produced
on the plots which had received superphosphates during the earlier years of
the experiments mean increases of only 2-3 per cent., they produced on those
which had been manured with slag-phosphates a mean increase of 5-8 per
cent.

57

CANE SUGAR.

9. The determinations of potash soluble in 1 per cent, citric acid and in
200th normal hydrochloric aoid showed that cultural operations have made
probahly available more potash each year than is required for the growth of the
sugar cane, the original samples yielding potash at the rate of 262 Ibs. and
278 Ibs. per acre to a depth of eight inches, those not manured with potash
salts during ten years at the rates of 376 Ibs. and 500 Ibs., and those which
received potash salts in addition to nitrogenous manures at the rates of 357 Ibs.
and 530 Ibs.

10. Judging from the solubility of the lime in the soil in 200th
normal hydrochloric acid, cultural operations set free in a soluble form more
lime than the crops utilized, the original soil yielding lime to the solvent at
the rate of, in round figures, 3400 Ibs. per acre to a depth of eight inches,
while the samples taken after ten years' cultivation yielded at the rate of
3800 Ibs. The soils which received in July, 1891, slacked lime, supplying in
round figures 6700 Ibs. lime per acre, yielded to the acid in 1902 a mean of
5000 Ibs. per acre, thus indicating after ten years' cultural operations a
retention in the uppermost layer of the soil of only 1200 Ibs. of added lime
in a readily soluble form.

11. The action of the lime on the solubility of the potash in the upper-
most layer of the soil appeared well marked, the samples from the not-limed
land yielding to 200th normal hydrochloric acid at a mean rate of 460 Ibs.
potash per acre to a depth of eight inches, while those from the limed land
yielded at the mean rate of 640 Ibs.

Finally, as a result of these analyses and experiments, Prof. Harrison lays
down certain precise and formal propositions of the greatest value to the
agricultural chemist responsible for the economic manuring of large areas of
sugar cane. These may be summarized as under : —

1. Soils which yield -007 per cent, phosphoric anhydride to 1 per cent,
aqueous citric acid with five hours' continuous shaking will not as a rule
respond to manurings with phosphates.

2. Under similar conditions soils yielding '005 per cent, to '007 per
cent, will benefit as a rule by phosphatic manurings.

3. It is advisable to apply heavy dressings of slag-phosphates or lighter
ones of super or basic phosphates to soils yielding less than -005 phosphoric
anhydride.

4. Soils yielding *008 per cent, potash can be regarded as containing
under the usual system of cultivation sufficient available potash for the needs
of the sugar cane.

5. If the potash lies between '005 per cent, and -008 per cent, it is
doubtful if the application of potash salts will result in remunerative returns.

6. Where the potash falls below *005 per cent, it is advisable to add
potash salts in the manures.

58

THE MANURING OF THE CANE.

7. The demand of the sugar cane for lime as a plant food is low, and if
a soil gives up more than '006 per cent, to the 1 per cent, citric acid solution,
it probably will yield sufficient for plant food for ordinary crops of sugar cane.

Barbados. — Harrison and Bovell4 in a series of experiments, carried out
between 1885 and 1889 at Dodd's Reformatory in Barbados, came to the
general conclusions detailed below : —

1. The addition of readily available nitrogen to mineral manures produces
a large increase in the weights of cane grown, but excessive dressing (over 3
cwts. sulphate of ammonia per acre) may cause a marked decrease in the rich-
ness and purity of the juice.

2. Under certain climatic conditions, manuring with nitrogen in form of
slowly decomposing organic matter may, if applied before or soon after the
planting of the canes, produce excellent results. Applications of such slow
acting manures in June or July at the period of the sugar cane's most active
growth are unadvisable, and may result in considerable loss.

3. Upon the soil, and under the climatic conditions existing at Dodds'
during the years 1885 to 1889, both inclusive, nitrate of soda was markedly
inferior to sulphate of ammonia as a source of nitrogen for sugar cane.

4. The profitable employment of purely nitrogenous manures depends
largely upon the state of the soil. If the soil is in good heart, such applications
may realize heavy returns, if poor such manurings will result in heavy loss.

5. For the maximum return of sugar cane by manuring, phosphates must
be present in the manures used.

6. If such phosphates are applied in the form of superphosphate of lime,
great care must be exercised in their use and application, as whilst light dress-
ings of superphosphate capable of supplying 75lbs. or SOlbs. per acre of "soluble
phosphate" (equivalent to from 16 to 18 per cent, of ''soluble phosphates" in
commerical sugar cane manures when applied at the rate of one ton to five acres),
may produce large increases in the weights of canes, &c. , heavier dressings do
not produce corresponding increases, and excessive ones may even reduce the
produce below that obtained when manuring with nitrogen and potash only.

7. The use of insoluble phosphates such as precipitated and mineral
phosphates is not advisable during the period of the cane's active growth, but
may produce excellent results when applied to the soil at an early period, in a
very fine state of sub-division in large quantities, and uniformly mixed with it.
To obtain, however, equally profitable results with these phosphates, as with
moderate applications of superphosphates, it is absolutely necessary that they be
purchasable at far lower prices than they can be at present obtained in
Barbados.

8. The addition of potash to manurings of phosphates and nitrogen pro-
duces in all soils at all deficient in available potash large increases in the yield
of cane and of available sugar in the juice per acre.

59

CANE SUGAR.

9. The most advantageous time for the application of potash-containing
manures appears to be at the earliest stages of the plants' growth, and pecu-
niarily the use at this period of so-called early cane or potassic manures is far
preferable to that of even the highest quality of manures which were formerly
used.

10. The presence of an excess of potash in the manures does not injuriously
affect the purity of the juice, either by increasing the glucose or appreciably
the amount of potash salts contained in it.

1 1 . No definite information has been obtained with regard to the influence
of the mineral constituents of the sugar cane manures upon the saccharine rich-
ness of the canes; although, in the great majority of cases, canes receiving
potassic manures have been somewhat richer in sugar than those otherwise
manured. It appears, therefore, probable that increased saccharine richness
must be sought in the cultivation of varieties, the careful selection of tops for
planting from healthy and vigorous canes (by this selection, whilst the sac-
charine strength of best canes of a variety would not be increased, the average
might be greatly raised), and possibly by the seminal reproduction of carefully
selected canes and varieties.

Mauritius.5 — A series of experiments made by Boname at the Station
Agronomique in Mauritius gave the results detailed below : —

Return in Tons of Cane per acre.

Plant

First

Second

Mean per

Manure.

Cane.

Ratoons.

Ratoons.

Year.

a, m, q, u

51-400

.. 35-710

. . 26-690

. . 39-600

b m a u

61-100

31-460

27-040

41*500

c, m, q, u . . . . . .

60-890

. . 37-800

. . 26-480

,, 41-729

d, e, f, m, q, u

61-300

. . 36-000

. . 25-770

. 41-020

g, h, i, n, r, u. .

54-210

. . 34-790

.. 25-820

. . 39-030

j, k, 1, o, s, w

48-360

. 30-530

. . 23-030

. . 33-940

Nothing . .

42-680

. 20-090

. . 14-330

. . 25-630

d, e, f , m, q

31-720

. . 18-000

.. 10-910

.. 20-210

d, e, f, TI . . . .

29-510

. . 15-430

.. 11-130

. . 18-690

m, q, u

35-660

. . 21-820

.. 13-610

. . 23-530

d, e, f, p, u . . . .

64-610

. . 37-040

. . 29-900

. . 43-850

d, e, f, t, u . . ....

64-680

. . 39-760

.. 31-790

.. 45-410

d, e, f , r, u . .

62-610

. . 39-980

. . 30-920

. . 44-500

d, e, f, m, q, u ....

58-100

. . 39-350

. . 30-410

. . 42-950

d, e, f, m, q, v. .

57-400

. . 38-080

.. 31-530

. . 42-330

d, e, f , p, q, v

52-700

. . 36-560

. 29-080

. . 37-440

d, e, x, m, q, u

46-100

. . 34-620

. . 24-360

. . 35-020

m, q, u

39-450

. . 28-370

. . 20-729

.. 29-510

d, e, f , u . . . . . .

27-670

. . 20-400

. . 13-290

. . 20-450

d, e, f , m, q

21-200

. . 14-310

.. 6-880

.. 14-130

60

THE MANURING OF THE CANE.

a, 30 kilos nitrogen as dried blood, b as sulphate of ammonia, c as nitrate of soda,
d, 10 ,, ,, ,, ,, e ,, ,, f ,, ,,

g, 13*3 ,, ,, ,, ,, h ,, ,, i ,, ,,

j> 6*6 ,, ,, ,, >, k ,, ,, ,, ,,

m 20, n 6, o 13-3, p 40 kilos soluble phosphates ; q 20, r 26'6, s 13*3 kilos in
soluble phosphate ; t 40 kilos citrate soluble phosphates ; u 30, v 40, w 20 kilos
potash ; x 20 kilos nitrogen as nitrate of soda.

Hawaii. — The result of a series of experiments led C. F. Eckart6 to
the following conclusions : —

1. Lands, capable of producing eleven tons of sugar to the acre without
fertilization, may be fertilized with profit, climatic conditions and water supply
being favourable.

2. While soils of high fertility may respond to mixed fertilizers, the
percentage of gain is greater as the soils suffer a gradual exhaustion.

3. The Rose Bamboo and Lahaina varieties of cane did not show the same
response to various combinations of fertilizer ingredients.

4. It is indicated that Rose Bamboo requires a larger store of phosphoric
acid to draw from than Lahaina for the best results.

5. Lahaina cane responded more to an increased supply of potash in the
soil than Rose Bamboo.

6. Both Rose Bamboo and Lahaina cane showed a considerable gain in
yields from fertilization with nitrogen. The percentage of this element in the
soil on which the tests were carried out was below the average for the islands.

7. On a soil containing phosphoric acid (soluble in a 1 per cent, solution of
aspartic acid) in quantities which were in large excess of those contained in
the average soil, phosphoric acid applied with nitrogen gave yields of Rose
Bamboo cane exceeding those obtained when nitrogen was applied alone.
Under the same conditions, Lahaina cane gave about the same yields following
fertilization with nitrogen as when nitrogen was applied with phosphoric acid.

8. On a soil containing potash (soluble in a 1 per cent, solution of aspartic
acid) in quantities comparing closely with those of the average island soil, Rose
Bamboo and Lahaina cane gave increased yields when this element was applied
with nitrogen.

9. The separate application of phosphoric acid in soluble forms to lands
standing high in phosphoric acid may result in a loss of sugar rather than in a
gain. It is indicated that the chances of loss are greater with Lahaina cane
than with the Rose Bamboo variety in localities where the two varieties make
an equally thrifty growth under normal conditions.

10. Separate applications of potash in the form of sulphate of potash may
decrease the yields of cane. The danger of loss is apparently greater with
Lahaina cane than with Rose Bamboo. This refers to applications of potassium
sulphate to lands under cane.

61

CANE SUGAR.

11. The fact that the application of one particular element gives negative
results with respect to fertilization does not warrant the assumption that the
element in question may, with profit, be omitted as a component part of mixed
fertilizers. Applied with another element, the gains may be considerably
greater than could be obtained with the latter element alone.

12. With both varieties the purest and richest juice was obtained from
the cane on the unfertilized area. In general, the plats receiving incomplete
fertilizers yielded juices of greater purity than those plats to which the three
elements were applied together.

Later experiments have resulted in the same authority stating7 : —

1. The profit resulting from the application of fertilizers or manures will
depend largely upon other factors than the chemical composition of the soil.
Providing certain plant food deficiencies represent the chief depressive influence
on crop yields, the response to appropriate fertilization will be commensurate
with the difference between the limitations exerted upon crop production
through lack of available plant nutrients and the limitations exercised by the
next restraining factor in order of importance after the material has been
applied. This latter factor may be physical, biological or climatic in character.

2. The relative effects of different combinations of fertilizer materials on
the growth of sugar cane when these materials are added to a given soil will be
determined chiefly by

(a) the extent to which their several ingredients directly or indirectly
lessen the deficencies of available plant nutrients ;

(i) the extent to which they cause the bacterial flora to approach an
optimum balance for the regular production of sufficient
nitrates or assimilable nitrogen compounds, and

(0) the degree and manner in which they produce physical changes in
the soil.

3. Owing to the fact that a definite relationship exists between the
efficiency of a fertilizer mixture and the quantities and proportions in which
its ingredients are associated, due to biological, chemical and physical effects
which its component parts have in a given soil, variations in the composition
of the mixture beyond certain limits may materially influence crop yields.

4. A more definite knowledge concerning the amounts and proportions of
fertilizer salts to use in a mixture for best results would on some soils yield
pronounced profits, while a lack of such knowledge may in some cases result
in a loss, especially when soluble salts are employed.

5. The greatest loss from the use of improper mixtures of fertilizers is
apt to occur on acid soils, and in such cases considerable risk is involved from
the continued application of mixtures containing ammonium sulphate, sulphate
of potash, and acid phosphate, when lime dressings are not previously made.

62

THE MANURING OF THE CANE.

6. While the chemical and physical analysis of a soil will usually prove
of value in indicating the best cultural methods to follow in maintaining or
improving its fertility, and may also indicate in a general way certain of the
plant food deficiencies in given cases, it cannot afford definite information as to
the amounts or proportions of ingredients in fertilizer mixtures which will give
maximum returns.

7. It is possible that the data from more extended field experiments with
a large variety of soils, when reviewed in connection with the comparative
analysis of the soils, using both, weak and strong acids as solvents, may indicate
a somewhat definite relationship between the analytical figures and the order
of importance which phosphoric acid and potash, should assume in cane fer-
tilizers in given cases.

8. It would appear that analysis of soils, with more special reference to
their physical qualities, reaction and content of organic matter, nitrogen, and
more readily soluble lime, may, with due consideration of the water supply
and climatic conditions, be relied upon to indicate such manurial treatment as
will result in a profit, although they will not afford definite information as to
the weights and proportions of ingredients in fertilizer mixtures which will
result in maximum efficiency.

9. Nitrogen is the most important element to be considered in the
fertilization of the sugar cane in the Hawaiian Islands, and when applied in
mixed fertilizers some risk of reduced efficiency is entailed if either the potash
or phosphoric acid (in the form of soluble salts) is made to exceed the weight
of this element.

10. Unless through past local experience or carefully conducted field
tests, it has been definitely determined that a modified formula may be
expected to give greater yields, it is safer, when applying nitrogen, potash and
phosphoric acid in the form of soluble salts, to have the mixed fertilizer con-
tain even quantities of these elements, which are not to exceed 60 Ibs. per
acre in the case of each element.

11. Field tests with fertilizers whose ingredients are mixed in varying
proportions will, if such experiments are accurately and scientifically conducted
through a sufficient period, give the most reliable information as to the best
manurial practice. Such experiments should be laid out in very long, narrow,
parallel and contiguous plats or strips, with the untreated check areas lying
immediately adjacent to the fertilized cane.

12. The great importance of 'resting' fields in rotation on Hawaiian
plantations, and growing upon them leguminous crops is very clearly indicated.
This applies more particularly to the irrigated plantations, where the supplies
of organic matter are in the majority of cases becoming greatly reduced
through successive tillage operations in a comparatively arid climate, and by the
favourable conditions created for bacterial activity through regular irrigations
under uniformly high temperatures.

CANE SUGAR.

Java. — Repeated experiments in Java8 have shown that under
conditions there prevailing, manuring with readily available nitrogen alone
leads to the best financial results. The flooding of the fields during the
period that they are under rice brings down in suspension finely divided soil,
which affords a supply of potash and phosphates. In addition, the system of
land tenure there prevailing does not justify the cane planter in adopting
measures towards the permanent amelioration of the soil.

Effect of Manuring on the Composition of the Cane.—

There is a wide-spread belief that heavy manuring adversely affects the quality
of the juice of the cane and under certain conditions this may be correct ;
thus in a district such as Demerara, where a short period of growth obtains, a
late manuring results in an impure juice. Possibly in such a case not only is
the maturity of the crop delayed, but a second growth of young cane is
stimulated and the comparison may become one of mature and of immature cane.
Again with heavy manuring, there is a consequent increase in the size of the
crop with less access of direct sunshine, and a delayed ripening is the result.

That judicious heavy manuring has no harmful effect is shown from the
results regularly obtained in Hawaii ; nowhere is a sweeter and purer juice
obtained, and nowhere is the manuring more intense. Here, however, owing
to climatic conditions peculiarly favourable, a great part of the harvest
consists of fully matured cane cut at the period of maximum sweetness.

Actual experiments on this point lead to somewhat contradictory results.
Thus Eckart9 found in Hawaii with unmanured cane a sucrose content in the
juice of 18-26 and purity of 90*69, manured canes affording a juice containing
from 16'40 per cent, to 17'85 per cent, sucrose, and of purity 89-16 to 90-60.
Conversely, however, the same authority has supplied me with data of an
experiment where, in three instances, an application of 1200 Ibs. of high grade
mixed fertilizer and 300 Ibs. of nitrate per acre not only enormously increased
the yield but gave a sweeter and purer juice.

Of the specific effect of manures, many ideas, supported or not by experi-
ment, may be met with. Lime is credited with producing a sweet and pure
juice in the "West Indian adage, " The more lime in the field the less in the
factory," and this idea is reflected in the quotations at the beginning of
Chapter V.

Phosphates are also believed to affect beneficially the sugar content of the
cane, and potash is reputed to have the reverse effect ; Harrison's experiments
already quoted fail however to countenance this idea.

There is a certain amount of evidence that canes heavily manured with
readily available nitrogen are more susceptible to fungus attacks than are
others ; this may be due to the production of a soft rinded cane due to rapid

64

FIG. 12.

STRIPED

BAMBOO.

SIZE

PLATE IV

THE MANURING OF. THE CANE.

growth, and possibly in the presence of infected soil or material the nitro-
genous manure may also benefit the development of the fungus. In Egypt,
it may be mentioned, on lands controlled by the Daria Sanieh manuring of
cane was not allowed.

On the whole the writer thinks that the bulk of the evidence points to
weight of cane only as being affected ; differences which may from time to
time be observed are probably due to different degrees of maturity or to other
uncontrollable factors vitiating the comparison.

Time of Application of Manure.— The experimental study of
the manuring of cane has in general pointed to the benefit accruing from
early application of readily available nitrogen, and as a matter of practical
experience it has been found that canes so treated make a vigorous, rapid
growth and better withstand a subsequent drought. In general plant
physiological experience it is found that a supply of readily available nitrogen
leads to a large leaf development, and the development of the stalk of the cane
is intimately connected with that of the leaf.

It is often asked if one or two applications of the same amount of nitrogen
are the more beneficial. Watts' experiments in the Leeward Islands10 point
to the one application system being the better, and he reasons on the following
lines : —

" These results lead us to make the suggestion that manures applied to sugar
canes will probably be found to be more efficient, both physiologically and pecuniarily,
if given in quick acting forms at a very early stage of the cane's growth, and we are
led to speculate if this may not be accounted for, on botanical grounds, by the
structure and manner of growth of the cane. We have perhaps been too prone,
when thinking of manuring crops, to have in our mind dicotyledenous-branching
trees, with many growing points, instead of the sugar cane, with its one growing
point, or ' top ' to each stem. The cane having lost its habit of seeding may be
regarded as a growing top and a stem. When the former has arrived at its full
development it may be taken roughly to be a fixed quantity ; old leaves fall away
and are replaced by new ones, so that the top remains fairly constant. The stem
constantly receives additions, and gradually ripens to form a dormant sugar house
chiefly filled with sugar, doubtless originally destined to provide for the growth
of flowers and the production of the seed, but now developed to a greater extent
than the feebly fertile flowers demand.

"The elements of plant food, including nitrogen, potash and phosphate, are
found in greater abundance in the ' top ' and leaves than in the stem ; hence it
is reasonable to suppose that in the early development of the cane plant, with its
system of top and stem, greater demand is made upon the plant food supply of the
soil in order to build up this top rich in plant food, than occurs later on when
the top, a comparatively fixed quantity, has been developed, and additions are being
made to the stem, which additions demand relatively large amounts of carbo-
hydrates, with comparatively small amounts of nitrogen, potash and phosphates.
Transference of plant material from point to point takes place freely, and it is
reasonable to suppose that the cells of the stem, as they pass into the dormant
condition, may pass on some of their nitrogen, potash and phosphate to be used in
:-;.... building up newer structures. We are aware of this transference of plant food in
the case of the leaves, where the faded and falling cane leaves contain much less
plant food than the actively growing ones.

65

CANE SUGAE.

" In order to have fresh information on this point analyses have been made
of fresh cane leaves, and of dry cane leaves, just as they were about to fall from the
plant but not actually fallen.

" The results are as follows, and show in a striking manner the nature of the
transference of plant food material from the leaf back to the stem as it ripens
and as its lower portion becomes dormant : —

ANALYSIS OF ASH.

Silica

Carbon

Iron oxide

Alumina

Lime

Magnesia

Potash

Soda

Phosphoric anhydride
Sulphuric anhydride
Carbon dioxide

Chlorine

Water .,

Deduct oxygen equal to Chlorine .. ..
Nitrogen

Green

Leaves.

46-26

3-52

•49

4-68
5-08
17-23
6 60
1-39
5-45
2-39
9-09
1-25

103-43
2-02

Trash

Leaves.

63-31

3-47

•38

•03

6-67

5-10

6-49

3-58

•93

5-18

1-97

1-83

2-59

101-53
•40

101-41 .. 101-13

•777 on dried '36 on dried
leaves. trash.

GEAMS OF MINERAL MATTEK IN ONE LEAF.

One fresh cane leaf contains -9688 grams of ash.
One fresh trash leaf contains -5304 grams of ash.

. <

Jreen Leaf

Trash Leaf.

Grams.

Grams.

Silica

•4419

•3321

Carbon

•0336

•0182

Iron oxide

•0047

•0020

Alumina

•0002

Lime

•0448

•0350

Potash

•1C45

•0340

Soda

•0630

•0188

Phosphoric anhydride ....

•0134

•0048

Sulphuric anhydride

•0520

•0272

Carbon dioxide

•0228

•0103

Chlorine

•0868

•0096

Water

•0118

•0136

Deduct oxygen equal to chlorine

•0193

•0021

Nitrogen

•9586
•094

•5304
•033

" If this manner of regarding the cane as a growing organism is correct, it may lead
us to modify some of our ideas concerning the manuring of sugar canes, and may account
for the better result obtained by applying considerable quantities of nitrogen in one dose
at an early stage, and for the smaller results obtained from the use of such a slow acting
manure as dried blood."

THE MANURING OF THE CANE.

The experiments made by Watts, described above, had already been
conceived as long ago as 1877 by Rouf in Martinique; his experiments and
conclusions, than which I have come across none others so complete, are quoted
in full from Delteil's Canne d Sucre. Rouf harvested, weighed and analysed
month by month a crop of cane planted in March of 1877. His results, which
I have translated into Ibs. per acre, are given in the annexed table ; they give
the weight of the crop and of the various bodies contained therein : on these
results he thus expresses himself : —

1. The absorption of minerals commences as soon as the development of
the plant allows, but evidently it is much more active if the plant finds the
necessary fertilizing principles at its disposal, and above all if the climatic
conditions are favourable.

2. The progress is moderated from the sixth to the ninth month ; then the
march of the elements rises to the tenth and eleventh month, the time of the
maximum absorption. At this period the total weight of stalks and leaves is a
maximum ; the cane has absorbed all the minerals and nitrogen, and the weight
of dry matter also is the maximum. By the tenth month the cane has absorbed
a maximum of the following elements : phosphoric and sulphuric acids, potash,
soda and silica. At the eleventh month the elements which lagged behind are
absorbed up to the maximum ; these are lime, magnesia and nitrogen, and the
elements which first reached a maximum have begun to be eliminated. In the
twelfth month, the elimination of the last three elements begins and continues
for all until the cane is ripe.

3. The cane should be manured early so as to place at its disposal
necessary food, and to accelerate the elaboration of sugar.

4. The elimination of the excess of potash, chlorides and soda from the
stalk and their transport to the top and leaves are ended when the cane is ripe.
In the top of the cane are accumulated alkaline chlorides, glucose, albumenoid
and pectic bodies.

The return of plant food to the soil by the plant as it ripens indicates the
agricultural economy of harvesting the crop at its period of maximum ripeness
as less plant food is then removed ; Rouf's analyses bring out this point very
clearly.

Method of Application of Manures. — On general principles
the proper form of application of the various artificial manures varies.

Nitrate of soda and also nitrate of lime, being readily soluble and not
being fixed by the soil (i.e., rendered insoluble), are applied as top dressings.

Ammonia salts are also readily diifusible, and are applied as top dressings.

Organic forms of nitrogen requiring the action of soil organisms must be-
buried in the top two or three inches of the soil.

67

CANE SUGAR.

MONTHLY COMPOSITION OF THE CANE (WHOLE PLANT).

After BOUF.

Lbs. per Acre.

Age of Cane.

Green
Weight.

Dry
Weight.

Ash.

Nitrogen.

Phosphoric
Acid.

Six months . . . .

21,054

4,072

275

20-2

10-3

Seven months . ....

44,608

7,366

360

35-5

15-2

Eight months S"v •'... . 73,302

10,597

444

38-0

27-3

Nine months . ,: , . " ... i 76,082

12,100

504

44-9

27-7

Ten months

82,008

16,290

628

55-2

39-2

Eleven months

76.558

18,363

576

60-4

37-3

Twelve months 65,377

16,505

467

55-2

36-7

Thirteen months 79,150

17,756

468

39-8

29-0

Age of Cane.

Sulphuric
Acid.

Potash.

Soda.

Lime.

Magnesia.

Silica.

Six months

14-1

36-0

2-2

7-1

13-1

139-1

Seven months

14-8

44-4

8'6

23-8

15-5

168-1

Eight months

18-7

79-0

7-9

26-1

24-6

200-5

Nine months

20-0

79-7

9-7

28-4

25-7

245-3

Ten months

21-9

97-3

21-4

46-7

26-2

322-0

Eleven months

19-4

71-5

13-6

58-4

36-7

293-3

Twelve months

14-3

62-0

8-8

33-0

25-9

232-4

Thirteen months

17-3

62-6

7-0

38-0

27-5

210-5

Cyanamide, to be assimilated by plants, must first be acted on by soil
organisms, and hence is generally applied before planting, especially as this
material has some harmful effect on the germination of seeds.

Superphosphates are also often applied as a top dressing, or are worked
in at a very slight depth. Stubbs recommends that they should be spread over
the whole area to be manured. Slag and mineral phosphates require to be
thoroughly incorporated in the soil.

Potash also, being readily and completely fixed by the silicates of the
soil, requires thorough incorporation.

There is no reason (and indeed in many ways it is advantageous) why
phosphate and potassic manures should not be applied to the soil during the
preliminary cultural operations before planting. The retention of these
materials by the soil is so absolute that no loss by leaching is to be
apprehended.

Valuation Of Manures. — The question of the valuation of manures
is a special subject of its own, and outside the scope of a work of this nature.

68

THE MANURING OF THE CANE.

In more than one cane growing district all manures intended for use on
plantations are analysed and controlled at the Experiment Stations now
generally considered a necessary adjunct to large cane growing districts; this
work but seldom falls to the estate chemist.

Taking the value of nitrogen in sulphate of ammonia as 100, the
following are the average values adopted for other constituents ; it should be
mentioned, however, that no uniformity obtains as between different districts.

Nitrogen in ammonia sulphate 100

Nitrogen in nitrate 90

Organic nitrogen . . 100

Water soluble phosphoric acid 25

Citrate soluble phosphoric acid 25

Insoluble phosphoric acid 10

Potash in sulphate 30

Potash in chloride 25

The valuation of materials such as seed cakes, tankage and packing house
refuse depends very largely on the degree of fineness of the material. This
also applies to basis slags, which are usually sold under a guarantee of fineness.
A slag 80 per cent, fine means that 80 per cent, of the material will pass
through a sieve with a mesh of 250 wires to the lineal inch.

Lime in Connection with Cane Growing. — A. study of the
analyses of the ash of the cane cannot lead to the conclusion that the cane is a
calciophile plant, and Harrison3 in his resume of twenty-five years' experimental
study of the manurial requirements of the cane has come to the same conclusion.

The benefits that follow the application of lime in many districts where the
cane forms the staple crop must not then be considered as due to specific action
of this material on the cane, but as due to its general effect in amelioration
of the soil.

The action of lime may be briefly summarized : —

1 . Correction of acidity in the soil, whether due to an excess of organic
matter, or due to long continued application of ammonia salts.

2. Amelioration of the physical condition of heavy clays.

3. Rendering potash available.

It is now generally considered better practice to apply moderate applications
of lime, say lOOOlbs. per acre, every five or six years, than to put on heavier
applications less frequently. This is the general rule in the Hawaiian Islands,
larger applications being only made on a few plantations possessing a distinctly
sour soil with much organic matter. However, some heavy clay adobe soils
have been treated there with success with as much as fifty tons of coral sand to
the acre ; this procedure recalls the system of marling once so prevalent in
English agricultural practice.

69

CANE SUGAE.

A point of very great interest in connection with cane growing and one
which has not, so far as the writer is aware, been thoroughly investigated, is
the lime : magnesia ratio best suited for the cane. Eor cereal crops generally,
for rice, and for such as have a large leaf development, evidence has been
brought forward by Loew11 and his pupils that the lime should be in excess of
the magnesia in proportion from 1*5 to 2 times as great. In the absence of
any evidence to the contrary it may perhaps be taken that a similar ratio holds
for the cane. That an excess of magnesia has a deleterious effect on the cane
has been shown by Eckart,12 who irrigated cane in tubs with both lime and
magnesia chlorides, and found a much better growth when the lime was in
excess of the magnesia than when the quantity of these two bodies was
mearly the same.

Quite recently Loew13 in Porto Rico has gone further into the subject in
special reference to the cane ; in that island he has found the soils containing
an excess of magnesia over lime. He quotes an instance of a cane soil suffering
from acidity, stiffness and an excess of magnesia over lime where an applica-
tion of 3000 Ibs. lime per acre increased the yield of cane 57 per cent. He
also writes : " The most favourable ratio of lime to magnesia in the soil for
cane will very probably be as 2-1, if both are present in an equal state of
availability. This can be inferred from experiments with maize by
Bernadini."

The hypothesis of Loew, though carefully elaborated, is not accepted by
many agronomists; it has been followed up chiefly in Japan by Aso and
others. The lime-magnesia ratio must apply to the soil water or to readily
soluble forms in the soil ; a hydrochloric acid soil extract showing an excess
of magnesia over lime would not be sufficient to condemn a soil on Loew's
hypothesis. It is of interest to note that in some Demerara soil water,
Harrison14 has found that with sulphate of ammonia manuring the molecular
ratio of calcium-magnesium was 1 : -77 ; with nitrate of soda manuring it was
1 : T52, and with no manuring 1 : 2*40, and with no cultivation 1 : 2- 57.

Yields of cane had become very deficient in the second and third cases but
Harrison does not commit himself to attach any special significance to these
ratios.

Distinction between Forms of Nitrogen.— Nitrogen is con-
tained in manures as nitrate, ammonium salts, or as organic nitrogen ; these
differ in their effect as regards ' availability.' It was formerly held that the
plant absorbed nitrogen as nitrate ; latterly it has been clearly shown that
ammonia salts may be directly assimilated. The organic forms of nitrogen
have first to be acted on by soil organisms before they are of use to the plant,
and hence they are not so rapidly available as nitrate or ammonia salts;
cyanamide, too, is not at once available, and has to be acted on by soil
organisms, but field experiments have shown that this substance has a high

70

THE MANURING OF THE CANE.

order of availability. Of the organic forms of nitrogen Stubbs ranks castor
pomace first, followed by dried blood and fish scraps.

Choice of Nitrogenous Manures. — As a general principle it
has become accepted that sulphate of ammonia is the better material to use on
soils containing a high percentage of calcium carbonate, since in such soils
conditions are generally favourable for nitrification. On the other hand it is
believed that in the absence of this body or on soils which are of an acid
reaction that nitrate of soda is the preferable source. The idea, however, that
nitrification is essential to the assimilation of nitrogen by plants must now,
however, be definitely abandoned, as a whole series of experiments, initiated in
1887 by Pitsch and terminating with those of Miller and Hutchinson in 1909,
have shown conclusively that plants can assimilate ammonia compounds
directly.

The long continued application of ammonia salts to certain soils may
result in an acid reaction therein with consequent sterility ; such a result has
been observed in light sandy soils at the Woburn Experimental Station. On
the other hand, the long application of sodium nitrate may result in the
deflocculation or puddling of the clay of soils, rendering them mechanically
quite unfit for cultivation.

So far as tropical cane experiments and experience go the mass of
evidence seems to be divided ; but Harrison14 is, however, of opinion that the
heavy clay soils of British Guiana have benefitted rather than not by the long
continued application of ammonium sulphate; this he is inclined to attribute in
part to the alkaline nature of the sub-soil water. In Java too, sulphate of
ammonia forms the source of available nitrogen. In the Hawaiian Islands
nitrate is extensively used as a stimulant, though ammonia salts form a part of
the high grade fertilizers also used ; in Egypt and in Mauritius, nitrates
are also extensively employed.

The organic forms of nitrogen are used with a different object to the more
readily available, and their use as the sole source of nitrogen seems confined to
Louisiana, where the simultaneous production of cotton seed meal may account
for this preference.

At the moment of writing nitrate of lime is being extensively advertised,
and this material may well become the most eflicient source of nitrogen for the
cane, but experiments with it are as yet imperfect.

Specific Action of readily available Nitrogen.— The

action of ammonia as an early cane manure is thus explained by Geerligs : —
Its application causes the sap to rise in the cane ; the leaves are unable to
elaborate this sap, and consequently the development of the undermost buds
is forced (tillering or suckering) ; the number of canes in a stool is thus
increased ; it is essential that favourable weather follow this forcing, else the
young shoots will wilt and die.

71

CANE SUGAR.

Choice of Phosphatic Manures. — All phosphates when applied
to soils are fixed, and rendered insoluble ; the rationale of the use of a soluble
superphosphate, as opposed to the use of an insoluble phosphate, is that the
solution of phosphoric acid is precipitated within the soil in a much finer state
of division than can be obtained by grinding an insoluble phosphate, and
mechanically ploughing it into the soil. Dependent on the type of the soil, the
phosphoric acid will be precipitated within the soil as phosphate of lime, or
iron or alumina. The former of these bodies is available to the plant, the
latter is not ; hence it is an axiom in manuring that superphosphates are suitable
for calcareous soils or such as contain a considerate proportion of lime carbonate.
On heavy clays such as constitute the cane lands of British Guiana super-
phosphates are contraindicated. On such, soils basic slag is the form of
phosphatic manure from which benefit is to be expected. It has been shown
by many experiments that on clayey and peaty soils, where an alkaline base is
required to neutralize the nitric acid formed by soil organisms, this form of
phosphoric acid gives the best results.

Artificial Manures. — The properties of the manures occurring in
commerce are briefly mentioned below : —

Sulphate of Ammonia. — The pure body contains 2T21 per cent, nitrogen,
and as found on the market contains about 20 per cent, nitrogen.

Nitrate of Soda. — This material is extremely hygroscopic. The pure
body contains 16'5 per cent, nitrogen, the commercial body containing about
4 per cent, of impurities ; these impurities are in English commerce grouped
together under the peculiar term of refraction.

Nitrate of Potash.— The pure body contains 13'8 per cent, nitrogen, and
46*5 per cent, of potash; it is but seldom used as a manure, the supply being
devoted to other purposes; in an impure form it however finds its way to
Mauritius from India, and being of local occurrence is used to a certain extent
in Egypt.

Seed Cake Manures. — The refuse of seeds, &c., that have been crushed for
oil, comes into the market in large quantities as manure. The plants that
most largely contribute are cotton, flax, castor oil, cocoanut ; their composition
of course varies with the origin. In general these manures can be used only
in the country of their origin, drawbacks of freight prohibiting their more
extended use. Some analyses of these materials, collected from various sources,

are given below : —

Nitrogen per cent.

Ground nut (Aracliis hypoyaea] 4'06 - 7 '94

Kapok meal (Eriodendnon anfraduosum) .'. ... 4'40

Castor cake (Ricinus communis) .. .... .... 4'20

Coconut meal (Oocos nucifera) . . ..-....:. ' 3 -62

Cotton seed meal (Gossypium sp.} . . ..-:.' ;. 7*00

Chinese bean meal . . ..-..-.. . . "-. . ' . . .-. 6'96

Soja cake (Soja hispida) »"; «.„....- ,.'": 6-12

72

THE MANURING OF THE CANE.

Cotton seed cake is largely used in Louisiana, and the other forms of
organic nitrogen are used to a certain extent in Java, where they form products
of the country ; some quantity of these materials also finds its way from India
to Mauritius. The refuse of indigo factories is also used in Java, and in
Mauritius the refuse from aloe fibre factories.

Dried blood, as it comes on the market, contains from 10 per cent, to 16
per cent, of nitrogen.

Fish scrap is of very variable composition, containing from 5 per cent, to
8 per cent, nitrogen, and from 5 per cent, to 7 per cent, phosphoric acid.

Tankage is the residue from packing houses, and is of variable composition ;
as it contains considerable quantities of bone it is also a phosphatic manure.
It is similar in action and composition to fish scrap.

Guano. — The original Peruvian guano has long been exhausted, and the
guanos now on the market are of recent origin. They differ much in composition
from those of long accumulation. Some bat guanos contain an extraordinarily
high amount of nitrogen, reaching up to 30 per cent.

Cyanamide is a synthetic compound of the formula CaCN2 ; it is sold
under the name lime nitrogen, German nitrate, or even as lime nitrate, from
which it must be carefully distinguished ; as it appears in commerce it contains
about 20 per cent, of nitrogen.

Nitrate of lime is manufactured and put on the market as a basic nitrate
of composition Ca (OH) N03. It contains about 12 per cent, of nitrogen,

Gypsum. — This material is sulphate of lime, and, in a sense, can not be
regarded as a manure ; it acts indirectly as a source of potash, which it sets free
in soils ; it is also used as a corrective of soil alkalinity.

Bwie manures contain from 4 per cent, to 6 per cent, of nitrogen, and from
40 per cent, to 50 per cent, of phosphate of lime; this form of manure is sold
as half-inch, quarter-inch, or as bone meal or dust, and is frequently steamed
to remove the fats. The nitrogen is of little availability, and the phosphates,
unless the bones are finely ground, are but slowly assimilated.

Mineral phosphates contain from 25 per cent, to 35 percent, of phosphoric
acid, and are occasionally used without previous treatment intended to render
the phosphoric acid soluble.

Superphosphates usually contain about 20 per cent, soluble phosphoric
acid, and in the form known to the trade as ' double superphosphate ' up to
40 per cent, to 50 per cent. They are prepared from mineral phosphates by
the action of sulphuric acid.

£asio slag is the material obtained as a waste product in the ' basic ' pro-
cess of steel manufacture ; it usually contains from 15 per cent, to 20 per cent,
phosphoric acid, and from 40 per cent, to 50 per cent, of lime, a portion of
which exists as free lime.

73

CANE SUGAR.

Reverted phosphate is the name given to a form of lime phosphate insoluble
in water, but soluble in ammonium citrate solution, and which is valued at as
high a figure as water soluble phosphoric acid. Superphosphates have a
tendency on storage to pass into 'reverted phosphate,' and this material is
manufactured and sold under the name of 'precipitated phosphate,' containing
from 35 per cent, to 40 per cent, of phosphoric acid soluble in ammonium
citrate.

Potash manures. — Potash is applied in cane-producing countries as pure
sulphate containing about 48 per cent, of potash ; the chloride is also occa-
sionally used. Kainit and other crude salts find a limited use in mixed
manures.

Practice of Cane Manuring in different Countries.—

In Java and also in Demerara readily available nitrogen, chiefly in the form of
ammonium sulphate, is to a large extent the only artificial manure applied.
In Java it is claimed that the rotation there followed puts on the soil a
sufficiency of other elements of plant food for the cane crop ; this is largely
due to the water used in growing the rice holding in suspension a large
quantity of silt, which is deposited on the land.

In Demerara it is also frequently the custom to apply up to 10 cwt. of
basis slag phosphate to the plant canes, especially if analysis by Dyer's citric
acid method shows a deficiency in this element. On the heavy clay soils it is
exceptional to find a deficiency of potash, notwithstanding the heavy drain
made on this element by the continuous crop of cane.

In Hawaii, where the largest yield of cane is obtained, relatively
enormous quantities of manure are employed; nitrate of soda is employed
largely on the irrigated plantations in the districts of little rainfall, and this
material, as well as sulphate of ammonia much less frequently, is used in the
spring of the second growing season ; the application reaches up to 400 Ibs.
per acre.

In the Hawaiian Islands the climatic conditions are such that it is
possible to obtain a period of growth from planting to harvest up to 24
months ; hence there are two growing seasons and the application of manures
before each has been found to be very beneficial. The practice is generally to
use mixed fertilizer in the first growing season and nitrate in the second.

In that district also a cold spell is annually encountered, when a check to
and yellowing off of the cane occurs ; this is probably due to a cessation of
the activities of the nitrifying organisms in the soil. It has been found by
experience that the application of nitrates at this time has a very beneficial
effect on the growth of the cane.

In addition a complete fertilizer containing on an average 7 per cent, to
10 per cent, each of nitrogen, phosphoric acid and potash is applied; the

74

THE MANURING OF THE CANE.

proportions of these ingredients are altered to correspond with, the analysis of
the soil. Up to 1000 Ibs. per acre of such a fertilizer may be applied, although
600 Ibs. is a more usual dressing. Basic slags are but little, if at all, used.

In Mauritius and Bourbon large quantities of pen manure were (previous
to the extended use of mechanical traction) employed, and the plant canes
seldom received any other fertilizer. To ratoon crops a complete mixture,
similar to that quoted above as used in Hawaii, is employed but in a much
smaller quantity.

In Louisiana, chiefly owing to its local production, cotton seed meal forms
the chief source of nitrogen, and superphosphate forms the source of
phosphoric acid. Owing to the abundance of potash in the soil this element
is seldom necessary, and its action in retarding maturity is a reason against its
use in such a climate.

In Egypt nitrate of soda is the chief source of readily available nitrogen,
applications being made to the young cane after an irrigation. The Nile water
used in irrigation brings into the soil a certain quantity of plant food, and the
rotations followed also reduce the necessity for such heavy dressings of manure
as are used elsewhere. A peculiar manure and of small value, collected from
the refuse of old villages and known as 'ruins manure,' is also used by the
fellaheen planters, as well as dove dung, to which a quite fictitious value is
attached.

In Barbados and other islands of the British West Indies pen manure
forms an important source of plant food.

Th.6 Ash. of the Cane. — In common with other economic plants, the
ash of the cane has been subjected to numerous analyses chiefly earned out
with the object of determining the demands made on the soil, and of con-
structing an agricultural balance sheet. The earliest of these analyses are those
due to Stenhouse of canes from British Guiana and the West Indies ; later
analyses are those due to Boname15 in Guadeloupe, to Maxwell16 in Hawaii,
to van Lookeren Campagne, and to Kramers in Java.

While there is no lack of material, the discussion of these results is beset
with enormous difficulty. In the first place a definition is required of the ash
of the cane ; that is to say, does the term include the ash of the entire plant,
or of the stalk only ? Secondly, the amount and composition of the ash varies
with the age of the cane, as is very clearly shown in the analyses due to Rouf
and already quoted. Thirdly, there is the effect of climatic variation.
Fourthly and finally, there is the question of the reliability of the analyses ;
that is to say, under equal conditions can consistent results be obtained?
This last point has been gone into very fully by Eckart9, who in duplicate
experiments in successive seasons failed to find any valuable correspondence

75

CANE SUGAR.

between the results. The experiments in question were planned by Maxwell to
determine the relative demands made on a soil by different varieties ; the weight
of cane, including its stalks and waste products and the weight of ash therein
was determined ; this observation combined with the anaylsis of the ash gave
data for the construction of a detailed balance sheet. The results of a second
season's determination gave, however, results quite at variance with those
obtained in the first. I do not then think that any very useful purpose will be
served by quoting in full these and similar analyses.

Reviewing however the analyses due to Maxwell, Eckart, Boname and
others, the following statements can be made : —

(a.) By far the greater part of the ash of the entire plant is contained in
the leaves, tops and waste matter; such is especially the case in Hawaiian, as
compared with Guadeloupe, canes. This relation will be profoundly affected by
the personal equation of the investigator as well as by conditions of growth and
period of harvest.

(l.J In the leaves and waste matter the predominant element is silica,
with potash second in amount ; in the stalks the position is reversed.

(c.) The lime and magnesia are present in approximately equal amounts,
sometimes one and sometimes the other being in excess ; the same statement
is true of phosphoric acid and sulphuric acid.

(d.) The quantity of nitrogen and ash contained in the entire Hawaiian
grown plant, per ton of stalks, is much greater than in the Guadaloupe canes ;
the yield per unit area is much greater in the former than in the latter, the
growth in Hawaii having taken place under heavy manuring, aided by copious
irrigation. This does not imply a greater drain on the soil, since the leaves
and waste matter are returned to the soil and most of that carried away to the
mill in the stalks is still available.

(*.) The ash of the entire plant lies within the following limits: —
Silica 45 per cent, to 50 per cent. ; potash 15 per cent, to 20 percent. ; lime
4 per cent, to 6 per cent. ; magnesia 4 per cent, to 6 per cent. ; phosphoric
acid 2 per cent, to 5 per cent. ; sulphuric acid 2 per cent, to 5 per cent. ;
in some instances comparatively large amounts of chlorides have been found,

The Amount of Ash contained in a Crop of Cane. —

In view of what has been written above, it at once follows that any attempt
to obtain a general balance sheet of plant food demands is fallacious ; dependent
on which series of analyses is taken, results varying several hundred per
cent, may follow. Thus in one extreme case in Hawaii 94 Ibs. of ash were
obtained per short ton of stalks, a figure falling to 15 Ibs. in one of Boname's
trials in Guadeloupe.

The Ash of a Plant in Relation to Manuring.— It has been
thought that the analysis; of the ash of a plant and the agricultural balance

76

THE MANURING OF THE CANE.

sheet would give information as to the proper combination of manures to
apply ; this idea demands that for any plant there is one particular ash
analysis which is most suited for it. The variation, however, is so great that
no ' best ash ' for the cane can be obtained, and this captivating hypothesis
breaks down on subjection to scrutiny, or rather is not supported, as regards
the cane, by sufficient evidence. It is conceivable, however, that an ash
analysis showing a low proportion of, say, lime might point to a deficiency of
available lime in the soil ; on the other hand a deficiency of lime in the soil
might be reflected in small crops rather than in a low percentage of lime in the
ash.

Connected with this subject is the " Analysis of the Soil by Means of the
Ash "; this point has been recently studied by Hall18, who thus summarizes
his results, obtained of course in a temperate climate (England) but none the
less generally applicable : —

1 . The proportion of phosphoric acid and of potash in the ash of any given
plant varies with the amount of these substances available in the soil, as measured
by the response of the crops to phosphatic or potassic manures respectively.

2. The extent of the variation due to this cause is limited, and is often no
greater than the variations due to season, or than the other variations induced by
differences in the supply of non-essential ash constituents— soda, lime, &c.

3. The fluctuations in the composition of the ash are reduced to a minimum in
the case of organs of plants, which, like the grain of cereals or the tubers of
potatoes, are manufactured by the plant from material previously assimilated.

4. The composition of the ash of the cereals is less affected by changes in the
composition of the soil than is that of root crops like swedes and mangels.

5. The composition of the ash of mangels grown without manure on a particu-
lar soil gives a valuable indication of the requirements of the soil for potash manuring.
Similarly the phosphoric acid requirements are well indicated by the composition of
the ash of unmanured swedes, though in this case determination of the citric acid
soluble phosphoric acid in the soil gives even more decisive information.

6. Pending the determination of phosphoric acid and potash 'constants' for
some test plant occurring naturally on unmanured land, the interpretation of soil
conditions from analyses of plant ashes is not a practicable method by which
chemical analysis of the soil can be displaced.

The Utilization of Waste Products as Manure.— In order
to estimate the quantity and distribution of the ash and nitrogen brought into a
factory, the writer made the analyses detailed in the Tables below, for a
factory working up to 50,000 tons of canes. The process used in the factory
was dry double crushing and simple lime defecation ; no sulphur or phosphoric
acid was used. In Table I. are given analyses of the ash of various products ;
in Table II. the total amounts entering the factory per 1000 tons of cane; and
in Table III. the distribution of the nitrogen and the constituents of the ash
over all the factory products, the amount in the canes being put equal to 100.
Inspection of these tables will show that on this particular estate the amount
of potash in the canes was abnormally high, and that of the lime equally low,
the phosphoric acid being present in moderate quantity.

77

CANE SUGAR.
TABLE I.

Juice.

Megass.

Canes.

Filter
Cake.

Sugar

Sugar
II.

Lees.

Yeast
Deposit.

Ash per cent

•67

1-00

•77

11-55

1-15

3-54

1-79

..

Lime

1-22

2-41

1-33

17-96

4-73

4-64

6-53

.

Magnesia

00

•<

4-72

2-92

3-96

5-11

2-70

2-95

3-98

Potash

^8

40-84

16-82

31-23

1-07

39-54

37-26

41-82

Soda

4*

5

2-18

1-53

1-92

Trace

1-90

1-63

2-32

Phosphoric acid . .

o

o

4-97

3-25

4-15

16-17

2-74

3-67

1-61

Sulphuric acid . . . . ;

PH

15-49

6-22

11-72

1-71

22-60

23-42

20-88

Nitrogen* . . , . .

•052

•028

•045

1-50

••

•101

1-96

*Per cent, on actual material.
TABLE II.

Total
Ash

Lime.

Mag-
nesia.

Potash.

Soda.

Phos-
phoric
Acid.

Sul-
phuric
Acid.

Nitro-
gen.

Canes
Used in manufacture
Juice
Megass

0

§

Lbs.
17300

10270
7030

Lbs.
295
850
125
170

Lbs.
690

480
210

Lbs.
5380

4190
1180

Lbs.
330

220
110

Lbs.
740

510
230

Lbs.
2040
590
1590
440

Lbs.
1010
80
810
200

Filter Cake
Sugar I
Sugar II
Lees
Yeast deposit

Per 1000 tons of c

1830
1620
690
7600

350
80
30
460

95
43
20
300

20
640
250
3180

20
10

180

310
45
25
120

30
370
160
1560

230

440
195

TABLE III.

Ash.

Lime.

Mag-
nesia.

Potash

Soda.

Phos-
phoric
Acid.

Sul-
phuric
Acid.

Nitro-
gen.

Canes

100

100

100

100

100

100

100

100

Used in manufacture .

288-0

28-9

7-9

Juice

59-4

42-4

69-6

78-0

66-6

68-9

77-9

80-2

Megass

40-6

57-6

30-4

22-0

33-3

31-1

21-5

19-8

Filter cake

10-6

118-6

13-8

0-4

. .

41-8

1-5

22-8

Sugar I

9-3

26-0

6-2

11-9

6-1

6-1

18-1

Sugar II

3-9

10-2

2-9

4-6

3-0

3-4

7-8

Lees

43-9

155-8

44-1

59-1

54-1

16-2

76-5

43-5

Yeast deposit . . . .

19-3

78

THE MANURING OF THE CANE.

The amount of plant food lost in the factory operations is that earned
away in the sugars together with the nitrogen lost in the combustion of the
megass ; roughly speaking the sugars carry away 10 per cent, of the ash
constituents contained in the canes, and 20 per cent, of the nitrogen is lost with
the megass.. In accordance with what has already been written, this would
represent a loss only half as great when referring to the whole crop — cane and
trash.

Although nearly the whole mineral and nitrogenous matters of the crop
are retained in the factory by-products, their economical return is a matter of
no inconsiderable difficulty. The filter press cake, rich in nitrogen and phos-
phates, is in a form easily handled, and its application presents no difficulty.
No loss of nitrogen need be feared if it be necessary to store the press cake over
lengthy periods, as the annexed analyses show. These analyses of press cake
from the same factory were made by the writer to test this point : —

Nitrogen per cent,
on dry matter.

Fresh press cake 1'173

Press cake 12 weeks old, exposed to weather T184

Press cake, 100 weeks old, stored under cover 1'189

Press cake, 100 weeks old, exposed to weather 1*172

The megass ashes, rich in phosphates and potash, are also readily applied ;
in this material the potash is in great part soluble in water, and if exposed to
rain the most valuable constituent is leached out and lost.

In the analyses given above, a material is referred to under the name
1 yeast deposit ' ; by this is meant the sedimentary deposit of dead yeast cells
occurring in the fermentation vats. For the particular distillery on which
this estimate is based, 2'5 gallons of a thick sludge of yeast cells were produced
per 100 gallons of wash; one gallon of this sludge contained l-43lb. solid
matter and *1961b. nitrogen, or 13'70 per cent, on the solids. There is here a
source of a concentrated nitrogenous manure which is often run to waste. The
deposit might be collected and applied in its natural condition or passed
through filter presses and obtained as a cake carrying 50 per cent, to 60 per
cent, water and 6 per cent, to 7 per cent, nitrogen. Per 1000 gallons of wash
about 50 Ibs. of such cakes would be obtained, and per 1000 acres about
20 tons would result.

The material which offers the greatest difficulty with regard to its
economical return is the lees or distillery refuse; the following methods
suggest themselves.

1 . Concentration to small bulk.

2. Destructive distillation and incineration of residue, collecting the dis-
tillates and recovering the phosphates, and especially potash, in the residue.

3. Irrigation of cane fields with lees.

79

CANE SUGAR.

4. Precipitation with lime and collection of the resulting precipitated
phosphates and nitrogenous matter.

5. Collection of the lees in ponds and subsequent excavation of the * lees
mud/ and application as manure.

The concentration of the lees to a density of 1 '25 would mean an evapora-
tion of 90 per cent, of their weight, and even if performed in an efficient
multiple evaporator would entail great fuel consumption in value over and
above the value of the product obtained. The same obstacle stands in the way
of the incineration of the residue, although certain beet sugar factories which
work up their molasses for beet spirit treat the 'Schlempe,' or 'vinasse ' (as
the lees are termed) for collection of potash residues.

Lees irrigation has been tried, and there is much to be said in favour of
this method of conservation of valuable plant food. Experiments in Scotland
have shown that the refuse from whisky distilleries is not, at any rate in the
quantities in which it would be applied, injurious to vegetation. Such a
scheme was once actually in operation in Demerara, but, the distillery being
burnt down and not re-erected, it was not continued.

Lees when treated with lime give a copious precipitate ; it was found by
direct experiment that to completely precipitate 1000 gallons, 1501bs. of
commercial lime were necessary. After treatment with lime, lees that con-
tained originally *01040lb. nitrogen per gallon now contained -00406 lb., so
that over 60 per cent, of the nitrogenous matter was recovered in the precipi-
tate. On nitration a sludge was obtained, in volume about 1 5 per cent, of the
lees treated; when dry this material contained 3-82 per cent, nitrogen. To
treat lees in this way would require no expensive outlay, but the method would
still let the potash run to waste ; per 1000 tons of cane, 4 tons more or less of
a filtered sludge carrying 50 per cent, water would be obtained, the material
containing about 1*9 per cent, of nitrogen.

The present method of utilizing lees is to run them into a pond or blind
trench, which is periodically excavated and the material obtained, a soft black
mud, carried to the fields ; this method, while allowing a considerable loss in
drainage, is expensive owing to the bulkiness of the material. "Where the
estate has a large quantity of cattle, and where the pen manure is systematically
collected, the lees can very well be absorbed by the soiled litter.

In many districts a distillery is not an adjunct of the sugar house, and
instead of having lees to dispose of, molasses form the refuse of the factory. In
Hawaii the molasses are sometimes returned to the soil in irrigation water, and
in Mauritius they often find their way to the manure heaps. Another way of
utilizing the molasses is to feed them to the plantation stock, and recover their
manurial value in the excreta.

80

FIG. 13.
WHITE

TANNA.

PLATE V

THE MANURING OF THE CANE.

In a Sugar Plantation there is little Drain on the Soil. —

A sugar estate ships only carbon, hydrogen and oxygen, none of which are
obtained from the soil ; the whole of the nitrogen and ash is contained in the
by-products — leaves, tops, press cake, molasses, &c., — and if these are returned,
the fertility of the soil should remain permanently unimpaired. This generaliza-
tion requires some modification. Few estates make white sugar, and the raw
sugars contain some part of the ash and nitrogen; in other cases molasses are
sold off the estate, and in the combustion of the megass the nitrogen and some of
the potash are lost ; loss of the first-named material also occurs in burning off
trash. To these causes of soil impoverishment must be added that due to
drainage waters ; notwithstanding, the agricultural cycle of a sugar estate is
very different from that of a farm where grain, roots, milk and live stock are
removed.

Bacteria in Relation to the Soil. — This subject, which is one
of the most important problems of the day, can only be touched on in bare out-
line. In the first place, organic matter buried in the soil is acted on by both
bacteria, and by fungi; a product (humus), richer in carbon and poorer in
oxygen than the original material, eventually results. In the presence of air
this action proceeds faster, and is more complete, than in its absence ; hence
the availability of organic matter, cane trash for example, and of manures
such as cotton seed cake, is more rapid in well tilled than in unworked soils ;
similarly, in stagnant soils, there is an accumulation of organic matter, as in
bogs and peaty soils. The products formed by the action of the soil organisms
are of an acid nature, and unless some base, such as calcium carbonate, is
present in the soil to neutralize the acids formed, bacterial action eventually
ceases, and what decay then occurs is due to fungi; in this case, too, the
decomposition is not so complete, and there is a tendency to the accumulation
of organic matter, in the soil. The form in which this organic matter occurs
may not be of benefit to plant life ; soils formed under these conditions may
contain large quantities of nitrogen, and yet be unproductive, until by tillage
and aeration, such a bacterial flora is obtained that the supply of nitrogen is
offered in an assimilable form.

A number of years ago a preparation of certain micro-organisms was put
en the market under the name of alinit ; it was stated to consist of a pure
culture of an organism known as Bacillus ellenlaclienns, and to it was attributed
the property of fixing nitrogen from the air ; it was observed to benefit soils
containing much humus, and to be beneficial in conjunction with slow acting
nitrogenous manures ; its action was probably due to its initiating bacterial
action on soils where the organisms, associated with the decay of organic matter,
were absent. The use of this preparation has now merely an historical interest.

The possibility of the utilization of the nitrogen of the atmosphere by the
higher plants forms one of the world's classical polemics.* It is at the present

* The fixation of nitrogen by the leguminosse is discussed under a separate caption.

81

6

CANE SUGAR.

moment accepted that, through the agency of certain bacteria, the nitrogen of
the air becomes fixed in the soil, and thus indirectly becomes available to the
higher plants ; the organisms that have been most studied in this connection are
the Clostridium pastorianum and the A%otdbacter chroococcum ; the latter is of
cosmopolitan distribution, ' varieties ' from different parts of the world show-
ing only minor differences ; a supply of calcium carbonate is probably essential
to its development, and the amount of nitrogen fixed is correlated with the
quantity of carbohydrate present. In this connection, and in special reference
to the cane sugar industry, Ebbels17 has indicated the use of molasses as a
source of carbohydrate. Although it is now certain that nitrogen in the
form of ammonia can be assimilated by some higher plants, yet it is as nitrate
that the greater proportion is taken up ; the working out of the cycle, whereby
the plant takes up its nitrogen, is due to Schloesingand Muntz, to Warrington,
to Frankland, and especially to Winogradsky. As a result of their investiga-
tions it has been established that the formation of nitrates takes place in two
stages ; two types of organisms are employed in the first stage, one, classified
as nitrosomonas peculiar to the old, and the second as nitrosococcus occurring in
the new world. These organisms convert ammonia salts into nitrites ; the con-
version of the nitrite into nitrate is effected under the influence of an organism
called nitrobacter, which is cosmopolitan. The factors influencing the activity
of these organisms are briefly as under : —

1. The limits of activity are 5°C. and 55°C., with an optimum
temperature of 37°C.

2. Their activity is diminished by the presence of much organic matter,
and by the presence of alkaline chlorides and carbonates.

3. A base is necessary to neutralize and combine with the acid formed ;
the most efficient base is calcium carbonate, but magnesia carbonate, and the
zeolites present in clay may also serve.

4. A supply of oxygen, and of carbon is necessary ; the latter may be
derived from carbonates, or from the carbon dioxide of the air.

5. A supply of water is essential, but not an excess, which is actually
harmful.

6. Absence of direct sunlight.

From the above it is seen that nitrification, and hence plant growth will
proceed best in a well tilled, well aerated, well drained soil, at a temperature
of about 37°C. and in the presence of a supply of calcium carbonate.

Conversely to the formation of nitrates, a degradation of these bodies
eventually to gaseous nitrogen occurs. This process known as denitrification
takes place under the influence of a variety of organisms, and the favour-

82

THE MANURING OF THE CANE.

able conditions are the reverse of those aiding nitrification, that is to say, it
proceeds in the absence of air, and in the presence of an excess of water and of
organic matter ; hence it occurs in badly tilled, unaerated waterlogged soils,
Dentrification has also been noted to occur when fresh stable manure, new
dung or even finely chopped straw is added to the soil, so much so as to depress
the yield below that obtained when no manure is added to the soil. In
addition, the combined use of stable manure and of the readily available forms
of nitrogen has been contraindicated ; this action is perhaps due to the intro-
duction of large numbers of denitrifying organisms, and to the inhibiting effect
of large amounts of organic matter on the nitrifying organisms. Howeverr
the experiments of Wagner and others, from which these conclusions were
drawn, were not made under conditions consonant with ordinary agricultural
practice, and contain nothing to warrant any fear of harm resulting from the
well-advised return to the soil of well -rotted stable, &c., manure as usually
practised as a standard agricultural process.*

Green Manuring. — Green soiling or green manuring is a practice
which has been carried on for generations past. In Europe the method
employed is to sow a catch crop of some quickly growing plant between the
harvest of the one and the seed time of the succeeding crop ; the catch crop
is ploughed into the soil and acts as a green manure to the following crop.
The principles of this practice are as follows. It had been known for a large
number of years that leguminous crops (beans, peas, clover, &c.), although
they contained large amounts of nitrogen, did not respond to nitrogenous-
manurings, and even frequently gave a smaller crop when manured with
nitrogen than when unmanured. It was eventually established by Atwater in
America, Marshall Ward in England, and Hellriegel and Wilf arth in Germany,,
about 1886, that leguminous plants are able to absorb nitrogen from the air.
The absorption is not made directly by the plant, but by the agency of bacteria.
If the roots of a leguminous plant be examined, there will be found attached
to its rootlets a number of wart-like excrescences the size of a pin's head and
upwards. These bodies, which are termed nodules, on being crushed and
examined under the microscope, are found to consist of countless numbers of
bacteria ; these bacteria, living in symbiosis or commensalism with the host
plant, supply it with, at any rate, a part of its nitrogen.

If then leguminous plants be sown and allowed to reach maturity, and
then be ploughed into the soil, there is placed in the soil a large amount of
nitrogen obtained from the air.

Green manuring as an integral part of cane cultivation is practised most
intensively in Louisiana and Mauritius, and to a limited extent in Hawaii.

*For more detailed discussions reference may be made to Hall's The Soil, and Hilgard's
Soils, which the writer considers the best books, in English, that deal with general agriculture^

83

CANE SUGAK.

In Louisiana, after plant cane and first ratoons have been grown, the land
is sown with cow peas ( Vigna unguiculata] , using from one to three bushels per
acre ; in August or September the peas are ploughed in and cane planted in
October. According to Stubbs, the crop of cow peas above ground is often
removed as fodder for cattle, planters who do this holding that the roots supply
sufficient nitrogen for the crop, but Stubbs states that when the green crop is
ploughed in an average increase over plant and first ratoon cane of 7*42 tons
per acre is obtained over that obtained when the green crop is removed for
fodder ; the amount of nitrogen afforded by a crop of cow peas is, according to
Stubbs, about lOOlbs. per acre.

In Mauritius there are four crops used as green manures : —

1. The Pois d' Achery (Phaseolm lunatus}.

2. The Pois Muscat.*

3. Pigeon Pea (Cajanm indicus}.

4. Indigo sauvage (Tephrosia Candida}.

The first two are pea vines growing in dense thick matted masses. The
pigeon pea is a shrub growing to a height of four or six feet ; the indigo
sauvage is also a shrub, but of rather less robust habit. The system generally
followed is to grow cane up to third ratoons ; the land is then planted with one
or other of the above crops, the time during which it is rested under the
leguminous crop being from one to three years, dependent on the land
available. Where land sufficient for one year's rest only is available, the pois
muscat is generally grown ; the pois d' Achery is generally allowed to grow for
two years, and the pigeon pea and indigo for three or four. All four crops are
planted from seed, which is sown about 15 to 18 inches apart. Where no land
can be spared to rest, one or other of the above crops is occasionally sown
between the rows of cane, and after a few months' growth cut down and
buried.

Although the benefits of green manuring are undoubted, it must be
remembered that the expenses connected with it are not small, and very
possibly where virgin soil can be had in abundance it may for a time be more
economical continually to take in new land than to renew the fertility of old.
The benefits of green manuring are most pronounced on estates which have
continually to plant on the same soil ; such estates are found in Mauritius,
Barbados, and other small islands.

Besides placing in the soil a supply of readily available nitrogen, green
manuring has other advantages.

* In Sugar and the Sugar Cane I, in error, stated that the Pois Muscat was Mucuna
atropurpurea ; the Pois Muscat is, I now find, economically identical with the Velvet Bean of
Florida classed as Mucuna puriens var utilis ; the only difference is that the Pois Muscat has
a black and the Velvet Bean a mottled seed ; this statement is based on the studies of
Bort, in Bull. 141, U.S.D.A. Bureau of Plant Industry, where the Velvet Bean is redescribed as
Stizolobium deeringanum.—(N .D.)

84

THE MANURING OF THE CANE.

1. The advantages of a rotation are obtained.

2. The deep tap-roots of leguminous plants bring available plant food
from the subsoil to the surface soil.

3. The ill effects of a naked fallow are avoided.

4. The interposition of a crop other than cane will act as a prophylactic
towards fungus diseases and attacks of insects, for if the habitat of these
parasites be removed for any length of time it must result in their diminution
or disappearance from lack of food.

In certain quarters, notably in Mauritius, after land has been under
Ieguminosa3 for a time, it is prepared for cane cultivation again by burning off
the greeD above-ground crop. This process would seem to destroy the very
benefits to obtain which the green manure was planted. Planters who follow
this system claim as good a result as when the green crop is buried, and point
to the saving in expense. To obtain definite information as to this process the
writer grew on small plots equal to 5^0- of an acre crops of the Phaseolu»
lunatus* and Mucuna utilis. The results calculated out to an acre were as below.
The crop in both cases was six months between planting and harvesting, which
was done when the seeds were ripe.

Phaseolus
lunatus.
Kilos.

Mucuna
utilis.
Kilos.

Weight, dry matter,

in green

crop

.. .. 1621

.. 2522

,, ,,

beans

132

.. 466

,, ,,

roots

.. .. 123

.. 80

Nitrogen

in green

crop

30-3

. . 54-0

» ,,

roots

.. .. 1'2

•7

,, ,,

beans

5-6

.. 16'7

Potash

in green

crop

. . . . 42-0

. . 46-5

,, ,,

roots

4-4

2-1

Phosphoric acid

beans
in green

crop

.. .. 1-2
11-4

9-5
14-4

roots

.r

.. .. 1-1

•4

» »>

beans

•7

4-2

It will be seen that about 80 per cent, of the manurial value of the crop
was contained in the green crop ; if this is burnt off the nitrogen is lost, but
the potash and phosphoric acid remain in a form readily available for the
coming crop of cane. The economy of burning off the green crop and losing
the nitrogen is comparable with the practice of burning off trash ; in any case
there is obtained a large amount of mineral plant food brought up from the
subsoil. The high nitrogen content of the bean straw, and the possibility of
using this material as bedding for plantation stock, and thus both conserving
it and obtaining a pen manure rich in nitrogen, is worthy of notice.

*Pois d' Archery in Mauritius; the 'Java' and 'Rangoon' beans of commerce.

85

CANE SUGAR.

Among other plants grown in tropical countries as green manure are,
fieslania aegyptica, Crotallaria pincea and C. lalurmfolia , Phaseolus semierectus,
Arachis hypogaea (the earth nut), Soja hispida (the soy bean), Dolichos Idblab
(the bonavist bean), Phaseolus mungo (woolly pyrol), Indigo tinctoria (the indigo
x)f commerce), and, in Hawaii, a variety of lupine.

The percentage of nitrogen in some of these plants is given below :18 —

Per cent. Per cent.

Water. Nitrogen.

Sesbania aegyptica 82*30 . . '68

Crotallaria laburnifolia 79 -80 . . '70

Phaseolus semierecttis 81*00 „. - '52

Arachis hypogaea Plant 80*00 . . -58

Arachis hypogaea Fruit . . 2*76

Rotations. — Different crops have a predilection for different forms of
mineral matter, and thus remove from the soil very different amounts of the
different constituents of plant food, so much so that the ash of a crop may con-
sist in general of one predominant constituent ; by growing continually one
and the same crop on the same piece of land there is then a tendency to
•exhaust one particular constituent. If, however, different crops be grown in
rotation, an element of plant food which was removed in large quantities in
one year is not absorbed to such an extent by the succeeding crop, and by the
time the crop first in rotation is planted a second time a sufficiency of the
particular material exhausted by this crop will have become available, due to
the natural process of disintegration which soils are continually undergoing.
As an example of such a rotation, the Norfolk system may be quoted ; this is
wheat, roots, barley, clover; the roots are consumers of potash, the wheat
takes up phosphates, the barley absorbs silica, and the clover feeds largely on
lime and magnesia.

It is especially to be noted in this rotation that the wheat follows the
leguminous crop of clover ; wheat is a crop that responds to a supply of nitrogen
in this case in part provided by the root residues of the clover ; the cane, too,
demands, as is shown in the manurial trials quoted above, for its successful
growth a supply of readily available nitrogen, and in certain districts a
leguminous crop precedes the cane crop.

Cane growing districts may be divided into those where the cane forms
the sole output of the soil, and those where it is alternated with other crops.
Into the first category fall the districts of Cuba, the Hawaiian Islands, British
Guiana, Trinidad, Fiji. In Java, Egypt and British India, a complete
rotation is practised, and in Louisiana and Mauritius the cane fields are
rotated with leguminous crops which are ploughed in.

In Egypt, on the lands controlled by the Daria Sanieh, cane was grown
for two years, preceded by a year's fallow ; following on the cane crop corn arid
clover weie grown; the cane itself was not manured, with the object of

86

THE MANURING OF THE CANE.

obtaining a sweet cane. Private owners follow a rotation of clover, wheat,
cane (no ratoonage), and manure the cane heavily.

In Louisiana the general rotation is plant cane, ratoons, and cow peas
( Vigna, unguiculata} ploughed in as a green manure.

In Mauritius it is general to grow cane up to third ratoons, after which
a green leguminous crop occupies the land for from one to four years.

In Java the following rotations are practised —

1. Cane, 'ground provisions,' rice, ' ground provisions,' rice, cane.

2. Cane, ' ground provisions,' rice, cane.

3. Cane, rice, ' ground provisions,' rice, cane.

In 'ground provisions' are included ground nuts, beans, maize, cassava, and
yams.

Where the sugar cane forms the main crop in India, the following typical
rotations, amongst others, are given by Mukerji19 : —

Bengal. — High and light soils. Rice (May to September) ; pulse or oil
seed (October to March) ; jute (April to September) ; pulse or oil seed
(October to March); rice (May to September); potatoes (October to
February) ; sugar cane (February to February) ; rice (May to September) ;
pulse (October to March), &c.

Punjab. — Dhainea (Sesbania aculeata] or sun hemp, (Crotalaria juncea), or
cow peas ( Vigna unguiculata) cut in bloom in August ; potatoes (October to
February); sugarcane (February to February), pigeon pea (Cajanus indicus)
or rice ; potatoes ; sugar ; sugar cane.

Whenever practised the absence of a rotation is a weak point in sugar
cane culture ; the rich fertile soils which are often met with in the tropics can
for a number of years support a continuous unvaried crop, but eventually they
must become barren. In certain countries, as Demerara, where abundance of
virgin soil awaits cultivation, proprietors can continually empolder new land
and allow that which has become barren to lie fallow, and after a space of time,
during which by the continued disintegration of the soil plant food has
become available, again plant the old abandoned land.*

The effect of continuously growing cane on the same soil has not been, so
far as the writer is aware, distinctly studied, but the following quotation from.
A. D. Hall20 with reference to the Eothamsted wheat experiments seems
broadly applicable also to cane culture : —

" Plot 10 has received an annual dressing of nitrogen only, in the shape of
ammonium salts since the earliest dates of the experiments. It will be evident from
the curve showing the crop production that, despite this long continued use of a
manure supplying but. one element of plant nutrition, the crop has been wonderfully
maintained. Whereas the average production over the whole period is increased by
the supply of minerals to the extent of 1'8 bushels, the nitrogen alone has produced
an average increase of 7*6 bushels, the unmanured plot being taken as the standard

*See Note in Appendix.

87

CANE SUGAR.

in each case. The curve, however, shows that the production on this Plot 10 is
declining, notwithstanding the great reserves of mineral plant food with which the
soil started. At the present time also the crop on this plot presents a very unhealthy
appearance, is very slow to mature, and is extremely liable to rust.

" We thus see that it is possible to grow a cereal crop like wheat, year after
year, on the same land for at least sixty years without any decline in the produc-
tiveness of the soil, provided an appropriate manure be supplied to replace the
nitrogen, phosphoric acid and potash removed by the crops. There is no evidence,
in fact, that the wheat gives a smaller yield when following a long succession of
previous wheat crops than when grown in rotation, although the vigour of the plant
does not appear to be so great. The real difficulty in continuous corn growing is to
keep the land clean ; certain weeds are favoured by the wheat and tend to accumulate,
so that the land can only be maintained clean by an excessive expenditure in
repeated land hoeing. Notwithstanding all the labour that is put on the plots, the
'Black Bent' grass, Alopecurus agrestis, has from time to time become so trouble-
some that special measures have had to be taken to eradicate it and to restore the
plots to a reasonable degree of cleanliness."

It does not seem altogether unreasonable to attribute in part the damage
done by fungus and insect pests to the continual growth of cane on the same
soil, as in this way the pests have a continuous habitat.

In discussing rotations it may not be out of place to refer to the toxic
excretion theory ; it was originally suggested by De Candolle that plants
excreted a toxic substance which prevented the continual growth on the same
soil, and in this way explained the benefits of rotations. After definite
abandonment this idea has been revived, mainly by Whitney and Cameron, but
its discussion lies altogether without the limits of the present text book.

Pen Manure. — In those countries which employ animal traction very
large numbers of cattle and mules are kept for transport purposes, and large
quantities of pen manure are produced annually, and it is remunerative to stall
the cattle at night with sufficient litter, such as dry cane trash, to absorb their
urine. In Mauritius great attention is paid to this source of manure. The
method adopted is as follows.

The live stock of the estate, which may number from two to three hundred,
are in great part kept in 'pares,' which may be from fifty to a hundred yards
square ; a portion of the pare is often covered in to provide shelter in inclement
weather. The whole area is covered with cane trash transported from the
fields and used as bedding. During the whole year if the supply of labour is
sufficient, the soiled litter is in a continual process of renewal and removal, the
bedding being replaced throughout on an average once a week ; on removal it
is placed on stone platforms or in basins ten feet deep, both platforms and
basins generally being about fifty feet square. The whole mass when com-
pleted is continually watered with fermented molasses and water or distillery
refuse, and sometimes with dilute sulphuric acid; the drainings collect in

88

THE MANURING OF THE CANE.

stone pits and are continually repumped over the heap of manure ; the object
of this is to rot the manure and at the same time to fix any volatile ammonia
given off. In from six to twelve months the manure is considered sufficiently
rotten to place on the fields, where it is applied at the rate of from ten to
twenty tons per acre to plant canes only, generally at an age of three months ;
or occasionally the cane holes are filled with the manure and the tops planted
on it.

The amount of manure made per animal per year is from fifteen to twenty
tons where bedding is used, and where the dry dung only is collected, from
two to three tons.

It is very often the case that manure making is forced, that is to say,
more straw than necessary to absorb the urine and contribute to the comfort of
the animal is brought in as bedding; the false economy of this proceeding is
apparent, but its practice is not uncommon.

The composition of the manure varies within considerable limits ; where
a reasonable amount of bedding has been used, the percentage of nitrogen
generally, in the writer's experience, lies between *6 per cent, and *8 per cent.,
falling to '3 per cent, to *5 per cent, where an excess of trash has been brought
to the stables or pens ; the potash and phosphoric acid do not seem to show any
variation dependent on the amount of bedding used, both lying between the
values *2 per cent, to *7 per cent. ; these figures refer to manure with from
70 per cent, to 80 per cent, of moisture.

The expense of making pen manure is very considerable ; the cost in
Mauritius varies from two to five shillings per ton, a portion of which expense
would be incurred in any case; the carting and application costs about one
shilling per ton, making the total outlay from three to six shillings per ton.
This expense is very considerable, and in general it may be said that where
stock is kept on the estate it will pay to carefully conserve their excreta, but
it will not pay to keep animals to make manure, or to force the production
beyond its natural limits.

With the general increase in the size of estates and the consequent neces-
sity for mechanical traction, pen manure is losing its importance, and its place
is being taken by artificial fertilizers. The fertility of soils in districts, such as
Barbados and Mauritius, over many generations is, the writer believes, to be
largely attributed to the extensive and well ordered use of the pen manure
manufactured on the estates. The modern tendency is to grow crops with the
aid of irrigation and of the more concentrated artificial manures, and it largely
becomes a question of the cost of the labour required to make and to apply the
pen manure compared with that required for the purchase and application of
the artificial manure. It is not yet known what will be the final effect on the
soil in several generations of the modern practice.

89

CANE SUGAR.

REFERENCES IN CHAPTER VI.

1. S. 0., 257.

2. S. C., '338.

3. W. L B., II., 6.

4. S. C., 52.

5. 5«W. 9, Sta. Agron., Mauritius.

6. Bull. 16, Agric. H. S. P. A.

7. Bull. 29, Agric. H. S. P. A.
S. L S. J., 66.

9. Bull. 12, Agric. H. S. P. A.

10. Pamphlet 30, Imp. Dept. Agric., West Indies.

11. Bull. I., U. 8. D. A.

12. Bull. 8, Agric. H.S.P.A.

13. Circular 12, Porto Rico Experiment Station.

14. W. I. B., IX., 35.

15. Cultur de la Canne a Sucre, p. 24.

16. Jour. Agric. Science, I., 87.

17. Agricultural News, July, 1908.

18. Das Znckerrohr, p. 227.

19. Encyclopedia of American Agriculture, III., 108.

20. An Account of the Rothamsted Experiments, p. 40.

90

CHAPTER YIL

THE IRRIGATION OF THE CANE.

A very large proportion of the cane crop is produced partially or entirely
tinder irrigation ; thus irrigation forms an important factor in the Hawaiian
Islands, in Java, in Egypt, in British India, and in Peru ; a few estates in
Mauritius are also irrigated. The West Indies, Louisiana, Piji, Australia,
and the island of Hawaii are districts which produce mainly under natural
conditions. It is only in the Hawaiian Islands (the writer believes) that
plantations have constructed and own independently their water supply ; in
the other irrigation districts the irrigation works are state-owned and
controlled.

Unit of Measurement. — Irrigation water is measured as a volume
flow per unit of time or as a depth per unit of area. In the first system the
cubic foot second or ' cusec ' is the generally adopted English unit ; this flow
is usually referred to the acre ; in the metric system the unit is a litre-second
referred to a hectare. The acre-inch is the usual unit of depth measurement
and this unit is equal to 101'5 tons, to 3652 cubic feet, to 22,736 imperial
gallons, to 27,294 U.S. gallons, and to 103,130 litres. In the Hawaiian
Islands, the plantation reckoning is in many million (U.S.) gallons per day, of
which 1,000,000 are estimated as necessary for each 100 acres in cultivation.

Hawaii. — On the islands of Oahu, Maui, and Kauai the crop is almost
entirely grown under irrigation. Irrigation was begun in Hawaii in 1907 and
is now developing. The system followed is one of short furrow irrigation,
the length of furrow being adopted to the nature of the soil. During the first
crop the water runs along the cane row ; in ratoon crops which are hilled up
the water runs between the row.

The following data are based on a report of Maxwell1 : —

During a period of growth of about 1 7 months the total water supplied to
the crop averages about 100 inches. Reference to the table below will show
that the young cane received less water than when more mature, but not so
much less as might be thought proportionate considering the different states of
young and of mature cane. The causes at work are twofold ; when the cane
is young the whole ground is exposed to the direct rays of the sun and to the
action of winds; when the cane is older the foliage shades the ground and
lessens loss due to evaporation, and to a large extent conserves water in the

91

CANE SUGAR.

soil. At twelve months of age the crop actually consumes in its economy ten
times as much water as a crop one month old, but owing to the causes
mentioned above the apparent consumption is much less disproportionate.

It was found by experiment in Hawaii that the best results were obtained
when the young cane received 0'5 inch per week ; less favourable results were
obtained when the water supplied was one inch per week, and when the
furrows were filled with water the cane came up yellow and sickly. As the
cane comes away it requires about one inch weekly up to three or four months,
alter which 1 -5 inches are necessary until the crop is in full vigour when three
inches and never more are required. These figures refer to natural and
artificial supplies combined. The reports quoted above give as a general figure
that 1000 pounds of water are required per pound of sugar produced, and
mention that certain plantations in Hawaii use much more water than the
quantities cited with less favourable results.

TABLE GIVING WATER USED IN PRODUCTION OF A CANE CROP.

Monthly Irrigation Water

Period of Application. Rainfall. Monthly.

Inches. Inches.

July ;., 0-94 .. 4-0

August 1-58 .. 4-0

September 0'88 . . 4'0

October 1-75 .. 3'0

November 1-32 .. 3'0

December 1-86 . . 2-0

January I'OO .. 4'0

February 3'75 .. 1-5

March 3'98 . . 3-0

April 0-85 . . 4'0

May 2-01 . . 4-0

June 0-88 . . 7'0

July 0-17 .. 7-0

August 1-90 .. 9-0

September . . 0'75 . . 8-0

October 2'92 . . 6'0

November . 0'47 . . 3'0

27-01 76-5

The following figures taken from the same source contain much informa-
tion regarding irrigation in Hawaii.

Gallons of water used by the crop per acre : —

Volume of the Volume of the Total water

Crop. rainfall per acre. irrigation per acre. received per acre.

Gallons. Gallons. Gallons.

1897-98 .. .. 1,260,150 .. 1,273,700 .. 2,533,850
1898-99 .... 728,990 .. 2,059,600 .. 2,788,590

Total consumption of water per pound of sugar produced : —

Weight of water Weight of Sugar Water used

Crop. used per acre. produced per acre. per Ib. of Sugar.

Lbs. Lbs. Lbs.

1897-98 -.-. , .. 25,338,500 ... 24,775 .. 1023

1898-99 27,885,900 , *>_ 29,059 . . 959

92

FIG. 19.

THE IRRIGATION OF THE CANE.

The privately owned irrigation works in the Hawaiian Islands are
unparalleled in other sugar countries, and are indeed comparable with
irrigation works developed in connection with any agricultural undertaking
elsewhere. Three methods of obtaining water are to be distinguished : —

1 . Pumping from subterranean sources.

2. Interruption of upland sources and conveyance to the plantations by
systems of canals, tunnels, syphons and flumes.

3. Collection of upland streams in reservoirs.

The pumps are mostly located at or near sea level as it has been found
less expensive to elevate the water through long pipe lines, than to sink shafts

at a high level and install regular mining

— . ,-J — 1 pattern pumps. At the moment of writing

(1909) the total water pumped daily to an
average height of 200 feet in the Hawaiian
islands is estimated at 595,000,000 gallons ;
the horse power required to effect this
service is estimated as 20,000. Of this
quantity of water 360,000,000 gallons are pumped in the Pearl Harbour
district of the island of Oahu ; 150,000,000 in Central Maui and the balance
on the island of Kauai.

The second method of obtaining water is developed chiefly on the islands
of Maui and Kauai, and latterly has been extended to some districts in Hawaii ;
altogether the ditches deliver upwards of 600,000,000 gallons daily.

The total capacity of the reservoirs in the Hawaiian islands is over
8,000,000,000 gallons; the largest is that at Wahiawa, on Oahu, holding
2,750,000,000 gallons, and hence of the same
capacity as that at Craig Goch, one of the
reservoirs supplying Birmingham, England.

O'Shaughnessy2 estimates that 1,000,000
gallons per day per 100 acres is the duty of
water in this district ; this is equivalent to 1 34
acre-inches in a year, not counting natural rain-
fall and evaporation, which may amount to 50
inches. In a crop period of 18 months, then, -^IG- 20<

22,800 tons of water per acre will produce 50 to 80 tons of cane. He
further estimates that owing to leaky ditches, reservoirs and unequal and
improper distribution, not more than one-third reaches the area of the cane
roots.

Peru. — In Peru cane is entirely dependent upon irrigation, the melted
snow of the Andes being the source of water The arrangement of the ditches
generally followed is shown in Fig. 19. The regadora, or main canal, leads
across the higher part of the field ; from this, by means of a temporary opening,
water is brought to the cavesera and is allowed to flow out and run over the

93

CANE SUGAR.

cintas or beds of five rows. The fields are all on the slope, and water is seldom
pumped back, but is allowed to flow on the fields at a lower level. Where
water is scarce the fields are arranged as in Fig W ; oa are dividing ridges
made with a hoe, and cause the water to run in a zigzag fashion over the field.
At planting, fields are irrigated every five to eight days, and after establish-
ment monthly, water being cut off three months before harvest. The water
supplied is not abundant, seldom more than equivalent to a rainfall of 20 inches
per annum ; but copious dews and heavy mists are frequent, and the perfect
control of water permits crops being grown with less water than if the canes
were supplied with a natural rainfall falling intermittently in varying
quantities.

Mauritius.— In Mauritius, in parts where the rainfall is extremely
scanty, a few estates are entirely dependent upon irrigation. A sketch of the
system usually adopted to water fields is given in Fig. 21 ; aa is the main
canal, sometimes built of stone, and sometimes formed in the ground ; bb are
channels formed in the fields down which the supply from aa is turned ; ec are
the cane rows along which the water is deflected by temporarily damming the
channel II. After one strip of the field has been irrigated, say, the one on the
right (Fig. %1\ the water from aa is turned into the second channel J#, and a
second strip watered, and so on.

FIG. 21.

The length of the strips in Mauritius is usually about 60 feet, and the
water flows only one way. From observations made by the writer an irrigation
of young cane took 3-86 inches of water per acre calculated over the whole
acreage. This large amount was in great part due to the system of planting in
holes ; these holes are about six inches deep by four inches wide and nine
inches long, and each one has to be filled with water and to overflow before
the current can pass on to the next hole along the row. The cost of irrigation
is for labour alone about one rupee per acre ; the water used is always, obtained
by gravitation from higher levels.

"West Indies. — The West Indian crops are mainly dependent on rain-
fall ; latterly, however, in Cuba, Porto Rico, and Jamaica irrigation schemes of
no inconsiderable magnitude have been incepted or are in actual operation.

94

THE IRRIGATION OF THE CANE.

Eegnoso estimates that in Cuba the majority of the plantations require every
ten days an irrigation equal to 1000 cubic metres per hectare, or 40 tons per
acre per day.

Egypt. — In Egypt, according to Ronna3, the cane is watered as soon as
it is placed in the furrow in the month of February ; other irrigations follow
every ten days until the end of August. From this time up to the end of
October every fifteen or twenty days, after which irrigation is stopped. The
water required at each irrigation is, according to Tiemann4, 1000 cubic metres
per hectare.

Demerara. — The method by which fields are irrigated will be easily
understood on referring to Figs. 38 and 39 ; a drain indicated by the line g is
dug parallel to the cross canal c, and connected to it. Down the centre of the
beds irrigation drains 15 inches wide and 9 inches deep are dug, along which
the water runs into the main drain /and thence to the drainage trench c.

In the * English ' fields, the main drainage trench is dammed at the
proper points and the navigation water is cut into the field so that the field
or fields can be swamped.

Although the water available in the rivers is beyond realization, irrigation
is but little practised and its results are often harmful ; the best ever
accomplished is the prevention of the entire loss of the crop. To the student
of sugar literature, soil and topographical conditions have a great resemblance
to those of Java where irrigation succeeds; the only occasions when the
writer has seen irrigation tried was in "English" fields when a system of
lateral seepage obtains. Harrison5 has demonstrated the alkaline nature of the
subsoil waters of this district and their toxic action ; such a system would
bring these waters to the surface, and here may lie the cause of the failure.
With a system of subsoil drainage the possibilities of irrigation are very great.

Java. — The irrigation works in Java are of great magnitude, and are
entirely under state control. Conditions here are entirely different from those
in Hawaii, due to the enormous native population (over 30,000,000) whose
interests in the water available (used by them mainly in the rice crop) are
zealously guarded by the Dutch Government, which apportions the amount of
water to be used by the European cane planters and by the native peasants.

Geerligs6 has given the following details of cane irrigation in Java : —
" In consequence of the intensive cultivation of the cane in Java the soil
is quite dried to a considerable depth and absorbs an enormous quantity of
water. This can be estimated at two or three hectolitres per bouw* per second
(equal to 3£ to 5| cusecs per acre) at planting ; if at the age of two or three
months the soil is gradually saturated, in the absence of rain, only sufficient

*A bouw does not seem to be a very definite area ; in one authority I find it put equal to a
hectare or 10,000 square metres ; in another to 500 Rhynland roods or to T67 acre. In a paper by
Kanmerling dealing with the water transpired by the cane a bouw is taken as 8000 square
metres, i.e. 1-97 acre. According to Geerligs, 1 bouw equals 500 square Rhynland roods or T75
acres. I have translated the quantities in this section into cusecs per acre, taking the bouw as
two acres, and the hectolitre as 3'525 cubic feet.— (N. D.)

95

CANE SUGAR.

water is applied to make up the losses from evaporation. This loss is, from
experiments upon the transpiration of the sugar cane, about '006 to '009 cusecs
per acre. Generally a flow of '0176 cusecs per acre is sufficient for the cane,
but the majority of irrigation works do not afford more than half this quantity.

" The nature of the soils determines the necessity for irrigations after the
rainy season has stopped : some soils contain so much water that irrigation is
quite unnecessary, the roots of cane aged 10 to 12 months being quite satisfied
with the natural humidity of the soil. In the case of sandy soils where
drainage is easy, or in very stiff clays where the deep growth of the roots is
prevented, so that the root system is contained in the upper layers, it is some-
times necessary to introduce a little water into the ditches to prevent the
drying up of the roots."

A point of great interest in regard to irrigation water in Java is the great
mammal value of the silt carried in the water. According to de Meijier7 the
Solo river carries on an average 1 kilo of silt per cubic foot ; the silt of the
Brantas canal water contains from -43 to -60 per cent, potash, from '35 to -65 per
cent, phosphoric acid and -25 to '27 per cent, nitrogen. It is this large quantity
of mineral matter in a finely divided state that saves sugar cane planters in
Java from the purchase of mineral manures.

Formosa. — At the time of writing, very extensive irrigation schemes,
under the control of the Japanese Government, are being pushed forward.

Economic Distribution of Water. ^So far as the somewhat
scanty information available on cane irrigation in Java allows an opinion to
be formed, it seems that the irrigation serves as a means of saving the cane
during the dry season and not, as is often the case in Hawaii, of obtaining the
maximum possible crop. It has been established that cane 15 months or so
old consumes and requires for its maximum growth the largest amount of
water, and in Hawaii such cane often receives as much water as it can utilize.
In Java, however, there does not seem to be a sufficiency for both young and old
cane ; in this case it is the former that receives the water as the older cane can
still remain in fair vegetative vigour on the supplies of soil water, where the
younger cane would fail to become established.

In Hawaii it not infrequently occurs that the supply of water is insufficient
to afford the optimum quantity to all the cultivation ; here there is a balance of
opinion in favour of stinting the young cane and giving the full amount to the
old cane. Mauritius experience favours the irrigation of young cane to the
detriment of the older.

Hence we have here a question of very great importance concerning which
no experiments seem to be on record, and which would be very hard to plan
satisfactorily.

Water transpired by Cane.— Maxwell1 found as the result of
experiment that when cane was grown in tubs, in seven months 79,310 grms.,
or 174-5 Ibs. of water were transpired by the plant, there being formed 568'9

96

FIG. 14.

STRIPED

TANNA.

2

3

SIZE

PLATE VI

THE IRRIGATION OF THE CANE.

grms. of water-free material, consisting of 31-8 grams roots, 53'9 grms. stems,
and 483*2 grms. leaves, or 147*8 Ibs. water per pound of water- free plant
material. The amount of water transpired in each month of growth was
found to be as in the annexed table.

Age of

: Age of

Time of

Cane.

Tran spiration .

Time of Cane.

, Transpiration.

Observation.

Months.

Grms.

Observation. Months.

Grms.

May..

.. 1

860

August . . 4

.. 19,800

June .

.. 2

6500

September. . 5

. . 20,050

July..

.. 3

. . 11,000

October ,Y 6

.. 21,100

Experiments due to Kammerling8 in Java showed that on an average one
stick of cane by its leaves transpired over its whole period of growth 250 c.c.
per day; this he estimates as equal to 3,500,000 litres per bouw over the
whole vegetative period, or equal to about 1800 tons per acre.

During the first month of drought in Java, Kammerling estimates the
transpiration per stick as 500 c.c. per day, and using this as a basis he reckons
that the replacing of the soil water thus transpired in a month requires 720,000
litres per bouw, or about 370 tons per acre.

Kammerling also observed that the transpiration of the Manila, Cheribon
and Muntok canes was as 5 : 4 : 3 ; i.e., the latter will remain in vegetative
vigour on the soil water longer than the former, and will be drought resisting.

Methods of Irrigation, — Hilgard9 distinguishes the following
methods: —

1. Surface sprinkling.

2. Flooding.

(a.) By lateral overflow from furrows and ditches.
(J.) By the check system.

3. Furrow irrigation.

4. Lateral seepage from ditches.

5. Basin irrigation.

6. Irrigation from underground pipes.

The first method can be seen in practice in Demerara, where in seasons of
drought the ' creole gang ' (the colony-born children of the imported Asiatic
labourer) are employed laboriously carrying water in buckets to the ' stumps '
or stools of canes transported from an abandoned field to fill blanks in one still
under cultivation ; this method can only be used where labour is of the
cheapest.

The second method is extravagant in the use of water, and is illustrated
in the methods described below as in use in Peru.

The fourth method is exemplified in the so called flooding of the 'English'
fields in Demerara mentioned above.

The fifth and sixth methods do not find application in cane planting.

97

CANE SUGAR.

The third method is the most rational method, and the one which is most
largely applied. The system advocated by Maxwell1 is shown in Fig. 22.
Water from the main water ditch A A is diverted into the laterals bb, andfrom
these laterals allowed to flow in two directions along the furrow in which the
cane has been planted ; this twin flow of water may be compared with the
diagram in Fig. 21, illustrative of the practice in Mauritius. In Fig. 22 the
laterals are only thirty feet apart, so that the water only flows fifteen feet ; a
longer flow results in those portions of the cane row near the lateral receiving
an excess of water, and those more remote not receiving enough. In case the
flow of water is scanty or the soil is very porous, such a system is necessary
so as to allow water to reach all parts of the field ; but it would often be

FIG. 22.

hard to lay out. As illustrative of a wasteful and harmful method of irrigation,
Maxwell gives the following diagram (Fig. 23\ where the water from the main
ditch A A flows along the cane rows for the whole length of the field
exaggerating the waste and damage due to long furrows.

The length of the furrow is very largely controlled by the porosity of the
soil ; with light, sandy, porous soils, a short furrow is necessary to prevent
undue waste of water; and where the soil is clayey, so that the water
penetrates more slowly, a longer furrow is allowable.

Quality of Irrigation Water.— Maxwell1 arbitrarily fixed the
* danger point ' of irrigation water at 100 grains of salt per imperial gallon;
Hilgard10 states that 40 grains is the usual limit. Eckart11 found cane in
lysimeters grew unchecked when the soil water contained 195 grains chlorine,
as sodium chloride, per U.S. gallon and obtained in lysimeters a normal growth

98

THE IRRIGATION OF THE CANE.

when irrigation water containing 200 grains of salt per gallon was used ini
excess, thus permitting good drainage from the porous soil employed in the
tests. He also found that gypsum and coral sand mitigated the harmful effect
of saline irrigation waters.12

The nature of the salt in the water has a profound effect ; sulphates or
carbonates of lime and magnesia are not harmful ; it is in the chlorides of the
alkalies that danger lies. The danger of such water lies in their abuse rather
than in their use ; if the soils to which they are applied are ill-drained so that
the salt can accumulate, the quantity soon becomes toxic ; the natural rainfall,
applications of a purer supply or heavy applications of the saline water, com-
bined with good drainage, so as to wash out the accumulated salt, permits
their safe use.

FIG. 23.

Conservation of Soil Water. — After the water has arrived in the
soil a great part is always lost by evaporation, and this is capable of control
within certain limits. A protective layer of soil in fine tilth prevents the upward
movement of the water by capillary attraction to the surface, and is highly
efficient in retaining water in the soil. Not less important is the nature of soil ;
soils containing much humus are especially water retentive, and this is capable
of control in the burying of the trash of the cane and in the plowing in of
green manure ; to a certain extent the benefits of these practices may be
attributed to the increased water holding capacity of soils treated in this way.

The velocity and flow of the wind are also of importance in determining
the evaporation from the soil, and loss in this way may be controlled by
planting wind breaks or belts of trees.

Another factor of very great importance is the humidity ; Eckart11 has
shown that this entirely masks the effect of temperature, so much so that a

99

CANE SUGAR.

rise in humidity of 12-5 per cent, decreased the evaporation 50 per cent.,
although the temperature rose 1'5° Fahrenheit.

Cessation Of Irrigation. — In Hawaii it is customary to stop the
supply of water when the cane has flowered. Such cane is usually harvested
from three to six months after flowering, and during this time little or
no growth takes place, the cane actually evaporating its own water ; and at
the same time it probably elaborates reducing sugars into cane sugar. Such
cane may receive during the time of ripening a small amount of water to
maintain its vitality.

Optimum Quantity of "Water. — Experiments by Eekart13
showed that under the conditions prevailing at the Experiment Station of the
Hawaiian Sugar Planters' Association, the maximum return of cane was
obtained with a three-inch weekly irrigation. Commenting on these results,
he writes: — " These experiments have a practical bearing on irrigation on
plantations, as they show that while the larger volumes of water gave an
increased production of sugar, such increase of sugar would, under some
conditions be obtained at a loss. For instance, if we were to take the average
cost of lifting 1,000,000 gallons of water one foot to be $0*09, where three
inches per week irrigation were applied it would cost $42-77 per acre at the
100 feet level. One inch of water at the same elevation would cost $14-90.
The additional cost of irrigation in increasing the yield of sugar 2081 Ibs.
would be 2-6 cents or 1*3 cents per pound. At 200 feet elevation, the cost per
pound of sugar gained by increased irrigation would be 2-6 cents, and at 300
feet elevation, 3-9 cents. Naturally, these calculations are for a soil similar to
that at the Experiment Station and receiving about the same rainfall."

Optimum Percentage of Water in Soil.— Eckart13 found that
when three inches of water was applied per week, the soil at the Experiment
Station in Honolulu contained on an average 31-38 per cent, of water; this
soil can according to him absorb 40'74 per cent, of water in situ; hence he
finds that the best results are obtained when the soil is saturated to 77 per
cent, of the maximum. This is a larger figure than is found with most other
crops.

Cost Of Irrigation.— The total capital expended in the Hawaiian
Islands on sugar cane irrigation is probably not less than £3,000,000 ; but
statistics are incomplete and this is certainly a very conservative estimate.
Amongst figures that have been published, may be quoted those referring to
Ewa, where the total cost of erection of pumps delivering 22,000,000 gallons
daily was £370,000' ($1,775,000). The Olokele ditch 13 miles long, through
a mountainous country and delivering 60,000,000 gallons daily, cost £75,000;
the cost of the Kekaha canal on Kauai, of the same length and capacity, was a
similar figure. The Koolau ditch built through very difficult country and ten
miles long cost £91,000; it delivers 80,000,000 gallons daily. The Kohala
ditch on Hawaii which is 14 miles long, 12 feet wide at top, 7£ feet wide at

100

THE IRRFGATION OF THE CANE.

bottom, and 4£ feet deep cost £83,000 ; this ditch is a private undertaking
and sells water to a number of plantations, the price charged being $2500 per
year per 1,000,000 gallons per day.

Stubbs14 quotes the cost of irrigation at Ewa as being $73*75 per acre per
year; of which $36'62 were for pumping and $37'13 were for labour. Another
estimate gives the cost of pumping with coal at $8*10 per ton, and expressed
per 1,000,000 gallons lifted one foot as —

$
Operating expenses .. .. .. .. -081

Interest 6 per cent *014

Depreciation . . *007

•102

"With oil fuel the total expenses are reduced to $'074 for the same quantity.
This cost of irrigation may appear prohibitive until it is remembered that
in the Hawaiian Islands the average return per acre on unirrigated plantations
is, year in year out, about three tons of sugar per acre, and on the irrigated
plantations about six tons, so that three tons of sugar, less cost of cutting,
hauling and manufacture, are to be credited against $7 3 '75 as the cost of
irrigation.

Some recent information regarding cost of irrigation in Porto Rico15 gives
not dissimilar figures ; it is stated that here $25 per acre is the lowest figure
for pumping expenses, and that it often reaches $50. An estimate of the
Patillas and Carite schemes in this island, designed to irrigate 13,000 acres,
gives the total cost as $1,215,000, or nearly $100 per acre.

REFERENCES IN CHAPTER VII.

1. U. S. D. A. Office of Exp. Stations, Bull. 90.

2. Trans. Am. Soc. Civ. Eng. 54, 129.

3. Les irrigations.

4. /. S. J., 50.

5. W. I. B., 9, 1-36.

6. Bull. Assoc., 19, 1412.

7. Trans. Am. Soc. Civ. Eng., 54, 40.

8. Proceedings I^tli Congress of the United Syndicate of Java Sugar Manufac-

turers (1900).

9. Soils, p. 234.

10. Soils, p. 248.

11. H. S. P. A. Agric. Bull 8.

12. H. S. P. A. Agric. Bull. 11.

13. H. S. P. A. Agric. Bull. 9.

14. U. S. D. A. Office of Exp. Stations, Bull. 95.

15. Wiilet & Gray's Weekly Report, 11, 11, 09.

101

CHAPTER VIII.

THE HUSBANDRY OF THE CANE.

The cane is grown under so many diverse conditions that no general
•sketch of its husbandry is possible. An attempt is made in this chapter to
give some short notice of the implements employed and the routine of
operation in the more important districts. Broadly speaking, the districts
where the cane forms a staple fall into two classes ; those where the culti-
vation is chiefly manual and those where animal or power operated implements
.are used. The former methods are chiefly employed in the presence of a
cheap supply of labour of Asiatic or African origin, but the physical con-
ditions of the district have also a large influence.

i

FIG. 24.

FIG. 25.

Manual Implements. — The manual implements used in the
cultivation of the cane are the hoe, the fork, the shovel and the cutlass. The
cutlass, two forms of which are shown in Fig. 24t is used in the British West
Indies as a weeding tool. In other districts this work is done with the hoe,
two forms of which are shown in Fig. 25 ; the short handled hoe is used in
Mauritius, and the long handled form in Dernerara ; besides being used to cut
down weeds, it is employed to hoe earth over the rows of cane and to make the
cane furrow ; in Mauritius this tool is also employed in making the holes in
which the cane is planted. The fork, Fig. 26, is employed in Demerara in the

102

THE HUSBANDRY OF THE CANE.

cultivation of the cane when forking bmJcs, i.e., turning over with thejfork the
soil between the rows of cane. The shovel, Fij. 27, is used in Demerara in
preparing the seed bed, and in digging drains.

Animal and Power Implements. — With few exceptions the
same implements that are employed in the husbandry of other plants find use
with the cane ; these include steam, gang ploughs, turn or mould-
board, shovel and disc ploughs, harrows, tongue and disc cultivators.
In this connection it is of interest to note that so long ago as 1848
Wray in the Practical Sugar Planter advocated the use of steam
ploughs and of cultivators ; he illustrated a turn plough operated by
one engine on the cable and anchor system; the horse hoes and
cultivators that he showed (and the use of which he strongly
advocated) differ but in detail from those in use at the present
time. His remarks on the use of these instruments are as true
to-day as they were two generations back, and are therefore quoted
below : —

"The hoe plough is the next instrument particularly deserving
of attention ; it is one of the most useful that the planter can employ.
This plough is used for the purpose of hoeing up weeds and loosening
the earth between the growing plants. It is provided with two
wheels, one in front of, and one behind the hoes, by means of which
the depth of the hoeing is regulated. It may be used with three
triangular hoes, each cutting 1 3£ inches wide, extending over 3 feet 6 inches
of ground, or contracted to a smaller width ; or the two hind hoes may be
replaced by two curved knives for cutting the weeds up on the sides of
the ridges. It is an implement of very simple construction and
in great use in England ; it is also one that will be found of
very great advantage on sugar estates, in cleaning between the
cane rows, and in loosening the soil about the plants. The
expanding horse hoe is an implement designed and manufactured
expressly for the colonies, and is already beginning to establish
for itself a very sure reputation amongst sugar planters. By
means of a very simple contrivance, it can be extended and con-
tracted at pleasure ; so that the planter can have it made to
expand even to 5£ or 6 feet, if he requires it, as he will in all
cases where he plants his canes at six feet apart ; whilst at the
same time, by having spare tines or shares of peculiar form, he
can vary the nature of the work to be performed by it. For
FIG. 26. instance, the instrument is suited for rooting up weeds and loosening
the soil between the rows of canes ; by taking off the tines and hoes and
replacing them with light moulding shares, the instrument is at once converted
into a moulding machine, whereby the young canes may receive two or
three successive mouldings as lightly and neatly as by hand labour.

103

CANE SUGAR.

" I consider this machine to be so valuable to the planter, that no sugar
estate should be unprovided with it ; it enables him to perform at a very
inconsiderable cost an amount of work which, when executed by hand labour,
is well known to be very tiresome and expensive."

FIG. 28.

Turn or Mould-Board Ploughs. — Turn or mould board ploughs
are so called because they cut from the soil a clean slice and turn it over top
side down, through the action of the mould board ; the single mould board
plough is shown in Fig. 28 ; a is the share, b the landslide, c the coulter,
and d the mould board. The coulter shown is of the knife type ; it may be
replaced by a rolling coulter, consisting of a revolving steel disc, and instead of
being hung from the beam, it may be bolted on to the share or may be entirely
absent. This type of plough is the instrument that is almost always used in

FIG. 29.

the preparation of land for planting crops of all kinds ; the plough may be a
single unit, or there may be a number of units forming a gang plough. The
double mould board plough is shown in Fig. 29, the lettering being as for the

104

PLATE VI

THE HUSBANDRY OF THE CANE.

single mould board plough. This plough throws a slice of earth on either side
of the share, and finds an extended use in the sugar industry in forming the
furrows in which the cane is planted, in opening irrigation channels, in 'bursting
out' the middle of the cane rows, and in turning over weeds between the rows
in young canes.

Disc Ploughs. — The essential part of the disc plough (Fig. 30} is the
revolving discs ; these are of concave shape and revolve about their centre ;
the slice of soil is turned over by the action of the concavity of the disc.

The disc principle was originally devised to lessen the draft on the plough
and these ploughs find use in tenacious soils, where the mould board plough
will not scour properly, and in very hard lands where it is not possible to use
the latter plough. In open loose soils the disc ploughs are inferior to the other
type.

FIG. 30.

By the use of two discs inclined towards each other, they may be used for
furrowing, and they also find one of their most extended uses in turning over
and burying the pea vines grown as a green manure.

Steam Ploughs. — This term applies only to the power by which the
plough is operated, the latter remaining essentially the same in principle as
already described ; instead, however, of there being only one plough, a number
are combined into one implement, the whole forming a gang ; as many as seven
may be united in one gang, the ploughs being either mould board or discs.
T wo methods of applying power may be distinguished ; in one the plough is
hitched directly to the engine which draws the plough across the field. In
the other two engines are required ; these are located on opposite sides of the
field ; each engine is furnished with a winding drum, and through the agency

105

CANE SUGAR.

of a wire cable draws the plough to and fro across the field, each engine
working alternately ; the plough is equipped with a double set of plough shares
on opposite sides, so that one set is tilted in the air when the other is buried
in the ground. This type, which is shown in Fig. 31 (PLATE YIL), is used
extensively in the Hawaiian Islands.

The Cultivator. — A form of cultivator which has developed from the
shovel plough or horse hoe is shown in Fig. 32; this instrument, in cane
growing, is drawn by animal power between the rows of cane, breaking up the
soil and at the same time destroying the weeds.

Disc Cultivator. — The disc principle has also been applied to culti-
vators, a form of which is shown in Fig. 33 ; this instrument is arranged to
straddle the row, the discs being set so as to throw dirt on to the row. Such
an implement finds its most extended use in Louisiana.

FIG. 32.

Cultivators can only be used in young cane, and when the crop is so far
grown as to prevent their use it is said to be laid by.

Harrows. — The harrow was devised as a means of lightly covering
seed laid down after ploughing with turn ploughs; in cane cultivation it
is used after ploughing to reduce the soil to a fine tilth, to break up clods and
to level inequalities. Its use may be supplemented by the employment of
rollers. The disc principle has also been extended to harrows.

Special Cane Implements. — In Figs. 34, 35, and 36 are shown
the J3enicia-Horner No. 1. Ratoon and Cane Disc Plough, which has found an
extended use in the Hawaiian Islands ; it contains in detachable parts a double
mould-board plough, a revolving knife, right and left hand discs, and a subsoil
plough; it may be used as a furrower either for planting or for irrigation, for
bursting out middles, as a cultivator for throwing soil on to the cane row or
with the object of hilling up the latter, for trimming and subsoiling the sides
of the cane row, and slicing and cutting the ratoon row.

106

THE HUSBANDRY OF THE CANE.

When used as a furrower for planting or irrigation the implement is
equipped with both right and left hand discs, with the double mould plough
and with the subsoiler ; when used to slice up ratoon cane the plough is
replaced by a revolving knife; when used for hilling up rows of cane the
revolving knives and discs alone are used, the subsoiler being detached.

In Fig. 37 is shown the Homer combined weeder, cultivator and harrow,
intended to be used where the growth of grass is very rank ; it was originally
designed to be used with the Hona hona grass of the Hawaiian Islands ; the
semi-circular teeth tear up the weeds and at the same time cultivate the soil.
The load of weeds gathered in the cradle can be discharged by lifting up the
handles of the implement.

FIG. 33.

Other special cane implements are the Stubble shaver and Stubble digger
in use in Louisiana. The former is a horizontal rotatory knife revolving
when the carriage, of which it forms a part, is drawn along ; it is used to cut
down stumps flush with the ground. The essential part of the Stubble digger
is a shaft on which are fitted blades arranged along a helix. When the
carriage is drawn along the rows of ratoon cane the knives revolve and break
up and pulverize the soil.

Preparation of the Land.— Although the greater part of the
cane sugar yearly produced is manufactured from cane grown on land that has
now been in cultivation for a number of years, and in many sugar producing
countries all available land is under cultivation, in some other countries virgin

107

CANE SUGAR.

land is still taken in, or old abandoned land that has fallowed for a number of
years and returned to its primitive condition is again put under cultivation.
In general the operations to be undertaken in putting in new land may be
briefly described as under : — The land is cleared of all trees and bush, the
heavy wood is put on one side to be used as fuel, or, if valuable, for export,
the small branches, leaves, and bushes being burnt in situ. Yery generally all
this work is done by hand and the cost, especially if heavy stones (as is often the
case in volcanic countries) have to be moved, is very great. The more modern
and economical method is to employ steam power; engines capable of
use either as traction or stationary engines are employed in many countries

Fm. 34.

for the purpose of hauling the heavy timber and large stones off the land ;
when new districts are opened up or when new land is continually taken in
such a process is almost essential.

The combustion of the vegetation on new land is from one point of view
entirely wrong, for the practice robs the soil of most of the nitrogen that^has
been accumulating for ages past ; but the expense of burying the vegetable
matter, the slowness of its decomposition, and the harbouring places it affords
for noxious insects are the reasons for maintaining this universal practice ; in
addition, the burning of the vegetable matter places in the soil a large
amount of readily available mineral plant food.

108

THE HUSBANDRY OF THE CANE.

After the land has been cleared in those countries which employ land
carriage, roads wide enough for carts to. pass are made through ,the new
sections, and the area divided up into . convenient fields ; the land is prepared
for cultivation by ploughing, either by manual, animal, or steam power.

Fm. 35.

When hand labour is employed, the soil is merely turned over by forks or
shovels ; in other cases the whole area is ploughed, cross-ploughed and horse-
hoed, and the soil properly broken up and aerated.

British Guiana. — In British Guiana and the Straits Settlements, which
are flat alluvial countries, a somewhat more complicated procedure is

FIG. 36.

necessary ; the area of the new plantation being decided, three dams formed
by the excavation of three trenches are thrown up. These dams are known
as the navigation or middle walk, sideline or drainage, and back dams, and they

109

CANE SUGAR.

enclose the piece of land which is to be put into cultivation ; more frequently,
however, a double section is formed with two sideline dams and a back dam as
empoldering dams, a navigation dam running in the centre of the two half
sections, and serving equally for both. In Figs. 38 and 39 are given plans of
the arrangements of field customary in British Guiana ; a is the navigation
dam formed by the excavation of the navigation trench b ; the navigation
trench continues up to the factory, and is used for the transport of cane and
produce, and also to supply water for irrigation and other purposes. This
canal is connected with a river, creek or lake ; or where this is impossible, a
large canal capable of supplying a batch of estates carries water from a river.
Many estates have pumping stations situated on a river, so that they^are nearly
independent of drought; on other estates a 'drought may cause the level of

FIG. 37.

water in the river or creek to fall so much that it is necessary to take sea
water into the trenches. At e are shown cross canals communicating with
the navigation trench, and terminating about 20 to 25 feet from the sideline or
drainage canal c ; the cross canals are used for the purpose of bringing the
punts or barges used for transport within access of the canes ; the main
drainage canal runs out to the sea or river. Drainage is either forced or
natural ; in the former case centrifugal or sluice wheel pumps are employed,
the first named being by far the most economical ; in the latter case the side-
line discharges at low tide into the sea or river. Between the cross canals
lie the fields, usually of area 10 to 20 acres, the distance from cross canal to
cross canal being about 500 feet. In Demerara two kinds of fields are

110

THE HUSBANDRY OF THE CANE.

ill

CANE SUGAR.

distinguished : Dutch fields, Fig. 38, and English fields, Fig. 39. In the
Dutch form the fields are divided into beds 35 feet wide, running parallel to
the navigation trench ; running down the centre of each field is the drain /
known as a tracker or four-foot, which communicates with the main drainage
trench ; between each bed are small drains i which discharge into the four-
foot. In the English fields the beds d run at right angles to the navigation
trench. There is usually one bed g called the dam bed, running parallel.
In front of the dam bed is a cross tracker h, and between the beds are the
small drains i. Through the centre of the field runs, as before, the four-
foot /. The drains i discharge both into the cross tracker, and thence
by / into the main drainage trench, and also directly into the main drainage
trench ; very often a centre cross tracker is also provided. The dam, called
the back dam, is not shown in the sketches. It is the last dam on the estate,
and serves to keep out Savannah water.

Approximate dimensions customary in Demerara are : Navigation trench :
16 feet- 20 feet top; 12 feet-16 feet bottom; 4 feet- 5 feet deep. Cross
canals : 12 feet top ; 9 feet bottom ; 4 feet- 5 feet deep. Small drains : 2 feet-
3 feet top ; 1 J feet-2 feet bottom ; 3 feet deep. Larger drains (trackers) :
5 feet top ; 3 feet bottom ; 4 feet deep.

No furrow is formed in the soil, but a seed bed three to four feet wide is
made with the shovel into which the seed cane is pushed in a sloping direction.
Between the cane rows is a space about four feet wide called the "bank ; often
on very stiff clayey soils a shallow drain known as a drill, running parallel
with the cane row, is made in this bank.

Louisiana. — In Louisiana, where the sugar lands are flat and alluvial,
little, if any, new land is now taken in for sugar-raising purposes ; the prepara-
tion of the old land is as follows. The soil generally bears a plant and ratoon
crop of cane followed by corn ; at the last cultivation of the corn the land is
sown with cow peas at the rate of from one to three bushels per acre ; an immense
mass of vegetation is produced which is ploughed in with disc ploughs as a
green manure. When the vines have rotted sufficiently the ridges on which
the cane is to be planted are formed with the turn plough ; drains are made at
right angles to the ridges ; these quarter drains lead into larger ditches, and
these latter into the main drainage canals.

Cuba.— In Cuba, before the era of United States influence, forest land very
imperfectly cleared was used for cane planting ; in such land stones and the
roots of trees were left in situ and no ploughing was attempted ; the land was
of such fertility that up to twenty successive crops of cane could be obtained
from one planting. When the land became unproductive it was allowed to lie
fallow for long periods, and afterwards was again brought into bearing ; by
this time the stumps and roots of trees would have rotted, permitting the use of

112

THE HUSBANDRY OF THE CANE.

113

CANE SUGAR.

the plough; such land was ploughed with the turn plough drawn by oxen,
and furrows made by the double mould-board plough. Of late years more
rational methods have been adopted, and the steam plough is now in use.

Hawaii. — Deep and thorough ploughing and good preparation of the soil
is a characteristic of this district. A typical routine is as follows : —After the
land has carried its last ratoon crop, a plough is run down the middle of the
row bursting out and shattering the ratoon rootstocks ; the land is then
harrowed, ploughed and, perhaps, cross-ploughed. "Where the contour of the
land permits steam ploughs, generally Fowler cable-operated balanced ploughs,
as shown in Fig. 31, are used; after ploughing a second harrowing is done,
following on which the furrows, and water courses on irrigated plantations, are
made with a double mould-board plough. Fertilizer may then be scattered on
the bottom of the furrow and mixed with a subsoil tyne cultivator ; usually
the application of fertilizer is delayed until after planting.

Mauritius. — For very many years past no new land has been available for
cane growing ; an essential feature of the system of cane growing there followed
is the well-advised green manuring given the land after the last (generally
third) ratoon crop has been taken off. After the land has been for a variable
period under the green crop, this is cut down and buried or burnt off ; after
lining off the field the holes in which the cane is planted are made with the
hoe. The entire preparation of the land is done with very cheap manual labour
of East Indian origin.

Java. — The imperative needs of the large native population of Java
demand a carefully regulated system of land tenure, and the self-contained
plantations found elsewhere are absent from Java. Cane is only planted one
year in every three, the land at other times being in the hands of native
cultivators ; cane generally follows rice, and a number of small separated areas
of rice is united into one cane field, the area of which is from one bouw
(1*97 acre) to 100 bouws with an average of from ten to twenty bouws.

The first operation is to level the small embankments that have been made
in the rice fields, and to separate the terraces and fields belonging to different
owners ; the rest of the operations are thus described by Prinsen Geerligs1 : —

"As soon as the rice is reaped, and sometimes during that operation, a deep
ditch is dug round the field in order to drain off superfluous water. Owing to the
wet rice cultivation the soil has been saturated with water during the last two or
three months, all kinds of reduction processes have taken place and oxygen fails
entirely. In order then to render the land fit for cultivation the soil must be
exposed to the action of sun and wind. To this end the field is divided by trans-
verse ditches into plots of one-quarter or one-fifth of an acre, and between these
ditches the rows in which the cane is to he planted afterwards are dug. Ordinarily
these rows are 30 feet long, 1 foot wide, a little over 1 foot deep, and 4 or 5 feet apart.
The excavated soil is heaped up between the rows. In some places where the
nature of the soil so allows, the land is ploughed first and afterwards the rows are
dug with the native spade. When the field is thus prepared it has the aspect of a
large number of trenches which remain exposed to the sun's rays for about six
weeks. It is still unknown what chemical action takes place during the drying of

114

THE HUSBANDRY OF THE CANE.

the soil but experience has taught us that this period of lying fallow is indispensable
in obtaining a good crop. The wet lumps of soil dry up during this operation ,
crumble to pieces and assume a lighter colour causing the mass of moist cold hard
lumps to change into a loose greyish powdery soil. During the weathering all
grass is carefully weeded out, and this is continued after planting until the cane
has grown so high that it keeps down the weeds by its own shadow. At the end
of the drying time the soil in the rows is loosened a little and the cane tops are
then planted in them."

A ground plan of a Java cane field will then appear as in Fig. 40 ; at d
is a ditch surrounding the field into which drain the cross ditches, which are
in turn fed by the small drains c separating the cane beds e ; the cane rows
are at I running across the beds.

1000

a

FIG. 40.

GENERAL AGRICULTURAL PROCESSES.— The agri-
cultural processes followed in connection with cane growing are discussed
below ; in general similar practices prevail in most districts ; differences are
determined by the use or absence of irrigation, and of mechanical cultivation,
by labour supply, and by purely local conditions.

Planting. — The seed cane is planted in rows or in squares, in furrows
or in holes. In furrow planting, which is most generally used, the furrow
may be made by the double mould-board plough or, less economically, by the
use of the hoe. The furrow is generally about two feet deep and two feet
wide ; the cane is in porous soils laid along the bottom of the furrow ; in clayey

115

CANE SUGAR.

soils the cane is often planted on the top of the furrow ; a section of the field
in the two cases will then appear as in Fig. 1^1. Where irrigation is used the
furrow is made to follow the contour of the field.

In some places, notably Barbados, Reunion, and Mauritius, the cane is
planted in holes ; these holes are from fifteen to eighteen inches long and eight
to twelve inches deep and wide ; the cane top or often two tops are placed in
this hole and covered with a layer of soil ; not infrequently the hole is filled
with stable manure upon which the top is planted ; in Mauritius it is customary
to count 3000 of such holes to the acre. This method of planting is one that
entails considerable manual labour, but in Mauritius it is not unjustly claimed
that canes planted in this way have a secure hold on the soil and are less liable
to be damaged in a strong wind than are the canes planted in furrows.

In Cuba and Barbados a system is common in which the canes are planted
in holes made in the soil by driving in a crowbar.

FIG. 41.

Amount of Seed Cane required per Acre.— This is, of

course, dependent on the number of rows per acre, and whether the seed cane
is planted in single or in double lines in the row. In an acre with rows five,
six or seven feet from centre to centre the length of the rows is approximately
8740, 7280, and 6270 feet ; taking the cane as weighing eight ounces to the
running foot, there will be required 4370, 3640, and 31351bs. of cane respectively
if the latter is laid in single rows.

Reynoso System. — The Reynoso system of planting cane frequently
referred to in the literature of the cane consists, so far as the writer under-
stands it, in planting the cane in parallel furrows spaced equal distances apart.
In his classical treatise Reynoso lays stress on the necessity of a proper aeration
and tillage of the soil, but his system, properly so called, consists of furrow
planting as opposed to planting in squares, as was and still to a certain extent
remains the custom in Cuba.

Zayas System. — This system, lately devised by Dr. Zayas in Cuba,
•consists in planting in rows up to twelve feet apart, and in the continuous
cultivation of the soil. Dr. Zayas does not advise the use of artificial manures
but of pen manure only ; he also proposes a selective reaping of the crop, the
immature stalks being held over. By the use of this system a much longer
period of profitable ratoonage is said to be assured to the cane.

116

THE HUSBANDRY OF THE CANE.

Width of Row.— In general it is the fertility of the soil that deter-
mines the most economical width of row ; in very fertile soil, the rows are placed
comparatively far apart to allow freedom of growth to the luxuriant crop, and
conversely as the soil becomes less productive a narrow row gives more economical
results. In practice the cane rows are from three to seven feet wide ; in Cuba,
according to Eeynoso, the standard width is 1-70 metre (=5 ft. 6 in.\ the
rows being the same distance apart. Eoname gives the average width of the
cane row in Guadeloupe as 1'30 to 1'50 metre (=4 ft. 2 in. to 4 ft. 9 in.).
The most economical width of row was the subject of inquiry at Audubon
Park, where it was found that the narrower the row the greater was the purity
of the juice and the yield of cane, but that in very narrow rows the increased
yield of cane was barely sufficient to pay for the extra amount of cane required
to plant up a field with narrow rows. Stubbs2 suggests that that width of row
which best admits of proper cultivation should be selected, and following on
this argument, five-foot rows have been adopted at Audubon Park.

Source of Seed Cane. — In most districts it is the young immature
top of the cane that forms the source of seed ; the use of this is defensible
on the grounds that this part contains little sugar, but much nitrogenous bodies
and salts destined as food material in the early stages of growth ; also the
accumulated experience of planters generally points to this part of the cane
furnishing the better seed. In Cuba, however, it is usual to employ the whole
cane. In the Hawaiian Islands, many planters consider Mas make the best
seed. Cane in those islands often stands long periods after flowering ; the eyes
at the upper joints sprout and grow to a considerable size forming a very
short jointed woody piece of cane, locally called a lala.

Where the harvest of one crop and the planting of the next proceeds
simultaneously, no difficulty in obtaining seed is experienced ; when, however,
planting and harvest fall in different seasons it is often necessary to draw
down canes of age six months and upwards dependent on climatic influences so
as to obtain seed.

In Louisiana, where it is necessary to carry over seed from the harvest
towards the end of the year to the time of spring planting, seed cane is
preserved buried in the ground (windrowing) ; or protected from the weather in
matelas. In Java, the system of cane nurseries (bibit gardens) distinct from the
plantations is in extended use ; some planters there grow cane solely for the
purpose of selling seed ; these nurseries are often situated in the mountains as-
it has been found that such seed afforded some protection against sereh. A
peculiar method in use in Ganjam is thus described by Subra Rao3. In July
seed cane is planted in a seed bed, so close as to leave no space between the
cuttings which are of three joints each. In the middle of August the cuttings
which have now sprouted are transplanted to a nursery about five times the size
of the seed bed ; the nursery is laid out in furrows about eighteen inches apart.

117

CANE SUGAR.

In the following May the crop is cut down and used to plant adjacent fields
or sold for seed to other cultivators, a portion being reserved to go again
through the above cycle.

The writer has been informed that a similar system obtains in Java ; in
this case he believes that the seed cane is planted in small baskets packed close
under shelters of the crudest description ; these cuttings are carried to the
fields and planted as soon as the seasonal rains have begun to fall.

Cultivation. — By cultivation is here meant the working of the soil
and the keeping down of grass and weeds during the period between the
planting of the cane (or spring of the ratoons) and the harvest of the crop. In
districts dependent on manual labour the operations include weeding and mould-
ing and forking.

British Guiana. — In British Guiana and in other places dependent on
manual labour a typical routine is as follows : — Shortly after a crop of cane
has been taken off, the soil in between the rows of cane is turned over with
agricultural forks; this process is known as 'forking banks;' in about a
month the weeds and grass that have sprung up are cut down with the cutlass,
the machete or the hoe, a process which will have to be repeated every one or
two months until the canes are of such a height as to keep down the growth of
weeds. Simultaneously with the weeding earth is hoed over the cane row, the
process being known as moulding ; in some parts, especially in Eastern Asia,
this moulding is carried to an extreme pitch, the cane rows being earthed up
to a great extent. In some places, as in Cuba under the old regime, the
keeping down of the weeds formed the only cultivation that the cane received.

Louisiana.* — Stubbs4 thus describes the routine followed at Audubon Park
in Louisiana : — " The land is broken flush with a large plough, pulverized with
a harrow, and bedded with two-horse ploughs. The rows are opened with a
double mould-board plough, cane planted and covered, and middles broken out
with the double mould-board plough. The quarter drains are opened six
inches between the middle of the rows and the ditches are cleaned. At the
proper time the cane is off-barred with the two-horse ploughs, scraped with
hoes, and when large enough is fertilized by scattering the mixture across the
open furrows and narrow ridge of cane. The dirt is returned as soon as
fertilizer is applied, the middles broken out deep and clean, and the turn
ploughs sent to the barn to remain until the next season. The disc cultivator,
with the three small discs on either side, is used for throwing dirt to the cane
at the first working, and the middle or diamond cultivator for breaking out the

* To those familiar with hand husbandry only, this description requires some amplifica-
tion. In the Hawaiian Islands off-barring is termed slicing the. ratoon row, and this term conveys
a better impression of the process ; the instrument used is a disc plough of the type shown in
Fig. SO ; it is drawn alongside the ratoon row cutting through the old roots, throwing the dirt
away from the row and leaving an open furrow alongside the cane ; after the furrow has been
exposed for two or three days the dirt is thrown back to the row by the aid of disc implements.

It should be noticed that animal power cultivation does not altogether dispense with
manual labour ; in all cases the weeds and grass in the row itself have to be cut down by hand
tools.

118

THE HUSBANDRY OF THE CANE.

middles. In the second and third cultivations two middle discs replace the
three used in the first, and are set to such an angle os to throw the desired
amount of dirt to the cane, and are followed each time by the middle cultivator,
thus completing the work with the two implements. At 'lay-by,' the large or
* lay-by ' discs are used, followed by the middle cultivator with its two front
shovels removed. By proper adjustment of the two instruments, ridges of any
desired height can be made and the cane properly laid by."

Hawaii. — On the irrigated plantations mechanical cultivation is not
possible and weeds have to be kept down by hand ; on a rainfall plantation the
grass is mainly kept down by the use of disc cultivators run astraddle the row
and turning the soil away from the cane ; this leaves only a small area to be
hand hoed. After the first hoeing, fertilizer is scattered between the rows and
incorporated with a tine cultivator or other implement, the soil being stirred as
much as possible. On ratoon fields, the first operation after taking off the crop
is usually slicing the row ; manuring follows at once after which the soil is
thrown back to the row by a disc cultivator run astraddle the row. A stubble
digger (an appliance consisting essentially of a series of small tynes revolving
on an axle as the carriage is drawn along), is then passed over the row so as to
mix the manure and soil and loosen up the latter ; weeds between the row are
kept down as described above.

Cuba. — F. S. Earle5 gives the following account of a method of cultiva-
tion advocated by the Cuban Experiment Station as the most practical under
the conditions there : —

"The system recently advocated by the Cuban experiment station, while it
has not yet stood the test of long continued use, promises to solve satisfactorily
the question of continued production of profitable stubble crops. It is as
follows :— Plough the land intended for fall cane in the winter or spring. Plant to
velvet beans in April or May. Plough these under with a disk plough in August and
September. Harrow two or three times with the disk harrow. In October open
deep planting furrows with the sulky double mould board plough, spacing them about
seven feet apart. Scatter tankage and potash or some similar complete fertilizer
carrying about equal parts of nitrogen , phosphoric acid, and potash in the bottom
of the furrow, at the rate of 500 Ibs. per acre. This is best done with a two-horse
fertilizer drill. A small cultivator shovel attached at the rear of the drill will serve
to mix the fertilizer at the bottom of the furrow. Now drop a continuous row of
seed cane in the bottom of the furrow. It is best to select plant cane or vigorously
growing stubble for see'd. Using that from old worn-out stubble fields is inadvis-
able, as it will make a weaker, less satisfactory growth. Cover with the disk
cultivator, setting the gang to throw more or less dirt, according to the condition
of moisture. If the ground is moist, germination will be prompter if the cane is
not covered more than two or three inches. If it is dry, it is necessary to cover
six or eight inches deep to prevent tho drying of the seed canes. In from one or
two weeks, or just as the canes are peeping through the ground, harrow the field
thoroughly with the smoothing harrow running lengthwise of the rows. This will
kill any small weeds that may be starting, and will freshen the surface of the soil
and greatly aid germination. When the young plants are well up so that they
show from one end of the row to the other, begin cultivating with the ordinary
riding two-horse corn cultivator, of course straddling the row so as to cultivate
two rows at once. The seven foot rows are so wide that there will be a strip in the
middle not reached by the cultivator. This can be finished by the ordinary walking

119

CANE SUGAR.

cultivator of the planet Jupiter type, or the narrow cultivator blades may be
removed from the regular cultivator, and eight -inch cutaway sweeps be bolted on
instead. These will have a wide enough cut to meet in the centre, and as thus
rigged the same implement makes a good middle cultivator. Cultivation should be
repeated throughout the winter as often ns is needed to keep down all weeds and
maintain a dust mulch. Before spring the growth of the cane will be so great that
the row can no longer be straddled, and the middles only can be cultivated. In
April or the first part of May sow cow peas broadcast in the middles, cover them
with the cultivator and the work is finished. Up to this point the plan does not
differ materially from the ordinary system except that the use of the riding corn
cultivator, which works so close to the row, makes it possible to almost dispense
with the expensive hoe. It is only the few weeds and bunches of grass that come
up directly in the row that have to be cut with the hoe, or better still be pulled by
hand. The line of cultivation thus outlined will leave the land practically level.
This is right for the red lands, since they have natural under-drainage, but in the
wetter black it should be modified by using disk cultivators which ridge up the
row as in Louisiana.

"As soon as the cane is cut, take an ordinary horse rake and drive so as to
cross the cane rows, raking the trash from one middle and dumping it in the next
one. This quickly and cheaply clears half the ground so that it can be ploughed
and cultivated, and it provides a double mulch of trash for the other half which
makes it so thick and heavy that practically no grass or weeds can come through,
and these middles will require no further attention for the season. Now plough the
cleared middles with a two-horse turning plough, throwing the dirt away from the
cane. Run the last furrow up as close to the cane stubble as possible. You will
not hurt the roots. They all died when the cane was cut, and the new ones will
form as the new shoots of cane begin to grow. If fertilizer is needed, it can now
be applied in this open furrow next the cane. On most lands, however, it will only
be necessary to use fertilizer every third or fourth year. Do not leave the furrow
next the cane open any longer than is necessary, but work the dirt back with the
cultivator, using some implement that will throw a little dirt back over the stubble.
Keep these alternate middles well cultivated until the beginning of the rainy season
and then sow them down to cow peas. This will be found much cheaper than the
ordinary plan of going over all the surface of the ground two or three times with
hoes, and it leaves the stubble cane in even better cultural condition than the plant
cane, for one side of each row is thoroughly cultivated, while the other side is
protected by a heavy mulch of trash, which serves perfectly to retain moisture.
The next year, of course, the middles are reversed so that all the soil is thoroughly
aerated, and pulverized every two years. And yet only half of it is exposed to the
depleting influence of tillage while all the trash is retained on the land and is
ultimately incorporated with it to add to its supply of humus, a substance so
necessary for successful tropical agriculture."

Fig. 42 shows a typical Cuban plough preparing land for planting ; this
photograph was taken in 1909, but the steam gang plough is fast superseding
the ox.

Strait Settlements. — The process of ' banking up ' which seems peculiar
to Eastern Asia is thus described by F. Campcn6: —

"Whenever the field gets grassy it is weeded and heavily moulded at the
same time, and then given time to grow, until the general stand of canes is from
about three to four feet high, when the time has arrived to give it the first banking,
which is done as follows : — The men go to the field and each of them takes a row,
which he weeds and very particularly takes off all trash, especially all the small
leaves at the bottom of the cane stools. After this, with a dry cane blade, he ties
the bunches together in such a way that each cane stool is separate by itself, and
after having done this he takes the hoe and makes a drill between the cane rows,

120

THE HUSBANDRY OF THE CANE.

doing this in such a way that, when lifting the earth he places it round the cane
row, taking care that everything is even, and the work when finished has the look,
as if the shovelman in Demerara had been digging a drill, a foot deep by a foot
broad, with the difference however that instead of having thrown the earth on the
so-called trash bank, he has spread it all over and about the canes, covering every-
thing lightly from cane-row to drill. When so finished this will give you a cane
row or bank, as it is called here, with a kind of rough drill, of a foot by a foot, on
each side of it. As to the drills no particular neatness or paving is required as
long as they are well in the middle and have the required depth and breadth.

" Nothing more is now done to the fields until the canes, after a couple of
months, have grown a little more, and so to say have from four to six joints, when
the same performance is gone over again, only with the difference that the labourers)
when taking- out another foot of earth from the same old drill, pack it on and
between the cane stools, and press it down and against them with their feet, so
that in time the canes have something to support them, and are able to grow
upright.

"The appearance of this last work or bank, when properly finished must be
something similar to an umbrella or the hut of a Zulu, and the more earth that has
been put around and between the ttools the better it is ; also the distance from the
top of the earth packed around the cane stool to the bottom of the drill must be
not less than three and three-quarter feet."

Trashing. — By this term is meant the removal of the dry and dead
leaves at intervals during the growth of the cane. The benefits or otherwise
of this practice are a matter of much dispute. The rationale of the process is : —

1. The removal of the dead leaves exposes the cane to light and air and
hastens its maturity.

2. The dead leaves afford harbouring places for injurious insects.

3. Water lodging in the space between the leaf sheaf and the cane pro-
motes the development of the eyes and the aerial roots to the detriment of the
cane.

4. The dry lea res being placed on the ground act as a mulch and help to
retain soil moisture.

On the other hand it is claimed that the ripening effect is small, that the
labourers in passing between the canes do much damage, that many leaves that
can still carry on their functions are pulled off along with those actually dead,
and that when these are pulled off some damage is done to the cane, preparing
the way for fungus attacks. The matter has been put to experimental test ;
Boname7, who writes strongly in favour of the process of removing the dead
leaves, found the following results: —

1 . Only completely dry leaves removed.

2. Canes trashed a llanc, i.e., a certain number of green leaves removed.
(This would be called bleeding the cane in the West Indies.)

3. No trashing.

i 2

Degree Beaume .. .. 8'10 .. 7'dO 7'70

Sugar per cent 13'40 .. 11-60 .. 12-20

Glucose 1-30 .. 1'56 .. 1'29

121

CANE SUGAR.

No record of the weight of the crop is given.

Eckart8 found very different results in Hawaii. In a very complete series
of tests carried on at the Experiment Station there, the plots that were not
trashed gave uniformly a higher yield of cane and a sweeter and purer juice.

The Disposal of Trash. — As an average of the data due to Max-
well, and already quoted, each ton of cane stalks produces, in the leaves and
waste matter, 1*95 Ibs. of nitrogen; let this nitrogen he valued at 7'5 pence
per pound, so that its value is then per ton of cane stalks 14' 6 pence. A crop
of 40 tons of cane will then contain in its waste matter nitrogen to the value
of £2 8s. 8d. When the trash is, as is often the case, burned off, this
relatively enormous quantity of nitrogen is lost. To agriculturists accustomed

FIG. 42.

only to European farming practice this custom is barely creditable. It is
defended on the following grounds : —

1. The cost of cane cutting is decreased if the fields are fired immediately
before harvest. In Demerara, where labour is very cheap, the saving is from
five to six shillings per acre.

2. The expense of burying the trash and of removing it from the cane
rows is saved.

3. The combustion of the trash also destroys fungus spores and noxious
insects. According to Dr. Perkins, however, in Hawaii the burning destroys
the parasites of the leaf hopper, the latter escaping by flight.

4. Fields in which the trash has been burnt off allow the ratoons to
' spring' to better advantage ; this effect is probably due to the setting free of
the ash constituents of the trash.

122

THE HUSBANDRY OF THE CANE.

These reasons are apparently considered to outweigh the loss of nitrogen ;
it must not however be forgotten that the burying of the trash puts into the
soil large quantities of humus, the importance of which in increasing the
water holding capacity of the soil and enabling the canes to pass through a
period of drought is very great.

"Wrapping9. — This process, the reverse of trashing, seems to be confined
to portions of Southern India, where in parts, the dead leaves are wrapped
round the stalk ; this process is partly intended as a protection against jackals
and partly to diminish rooting and sprouting habits.

Selective Harvesting. — In healthy cane there is a point at which
the cane contains a minimum of, or even no, reducing sugars and when it is
at its maximum purity ; after this point there is a breaking down of the cane
sugar into reducing sugars and the cane is over ripe. In some varieties this
reversion is very rapid and it is also influenced by climatic conditions ; it is
then a matter of great importance to harvest a field of cane at the time of its
maximum purity ; the system under which this selective reaping is pursued is
thus described by Prinsen Geerligs10 : —

" The cane fields are divided into plots which have been planted and
manured at the same time and in the same way. After ten months of growth
take from each plot 40 normally grown cane stalks, and mark and number them.
Every fortnight one cane stalk is cut from each one of the stools and the
bundle carried to the laboratory, where the green top end is removed and the
canes are measured, weighed, and crushed in a small test mill, after which the
juice is analysed. The analytical data from each analysis of the test plot are
entered down, so that an increase of sucrose content or purity, or a falling in
them, can be detected at once. As soon as the sucrose content or purity cease
to augment, the cane of the plot under review has attained its point of
maturity, and should be cut in order to prevent deterioration by too long
standing in the field."

In some instances this process is followed in conjunction with a portable
travelling field laboratory.

Ratoonage. — The period to which canes are allowed to ratoon varies
in different countries ; in Java the great majority of the crop is plant cane only;
in Louisiana plant and first ratoons are grown ; in Mauritius it is customary to
grow up to third ratoons ; in Cuba, the West Indies and in British Guiana
fifth ratoons are not uncommon, and fields can be found that have not been
replanted for a generation; in Hawaii canes are seldom allowed to grow
beyond second ratoons. The economic limit to which canes can be ratooned
can only be determined by those on the spot and familiar with local conditions.
Long continued ratoonage has been connected with the prevalence of various
forms of root and root stock diseases, as in this case the cane fungus has a con-
tinuous habitat.

123

CANE SUGAR.

Cutting Back, — The flowering season in the Hawaiian Islands is
during the months of November and December. Cane that has been cut
early in the year will flower that same year and will have to be harvested after
a twelve months' growth; such cane is termed short ratoons. By allowing
such cane to grow till June and then cutting it back, it can be carried over the
flowering season of that year and will flower in the November of the following
year, thus giving a 1 7 to 1 8 months' period of growth from the time it was cut
back till it flowers, and a total period of growth of not less than two years by
the time it is harvested. Such cane is called long ratoons.

Period Of Harvest. — The time of harvest in the more important
cane growing areas is as shown below : —

British Guiana. — September to December.
Cuba. — December to June.
Java. — May to November.
Mauritius. — August to December.
Louisiana. — October to January.
Hawaiian Islands. — December to September.
Peru. — October to February.
Brazil. — October to February.
Argentina. — June to October.
Egypt. — December to March.
Queensland. — June to November.
Mexico. — December to May.
Philippines. — September to March.
West Indies. — January to July.

Influence of Arrowing on the Cane. — Arrowing marks the
end of the vegetative period of the growing cane. It has been thought that
arrowing had an influence on the sugar content of the cane ; definite experi-
ments by Harrison11 and by Prinsen Geerligs12 have shown that this belief is
unfounded. After the cane has arrowed no further formation of sugar takes
place, but an elaboration of that already formed obtains with an increase in
the cane sugar content and in the purity ; eventually however the cane dies
down and then a breaking down of the cane sugar occurs. The time to which
cane can be left standing after arrowing is very variable and is dependent on
variety and climate. In the Hawaiian Islands cane may remain as long as six
months after arrowing, before deterioration sets in.

Yield of Sugar per Acre. — The yield of sugar per acre is deter-
mined by the fertility of the soil, by the action of fertilizers, by climate, by
variety, by the efficiency of the cultivation, and by the efficiency of the manu-
facturing processes. Without doubt the highest returns have been obtained on
the heavily fertilized, systematically irrigated, porous, volcanic, basaltic soils
of the Hawaiian Islands; as much as 30,000 Ibs. of sugar have been there

124

THE HUSBANDRY OF THE CANE.

obtained per acre of land over large areas and returns of 20,000 Ibs. are not
unusual ; on an average, however, the irrigated plantations there yield about
12, 000 Ibs. per acre from a crop of plant cane and long and short ratoons. In
Java, the average return has reached 11, 000 Ibs. per acre and returns of this
magnitude are also known in Peru. A Consular report gives the production in
Cuba for the year 1909 as 14,214,946 long tons of cane from 849,000 acres,
or 16-7 tons per acre ; with a recovery of 10 per cent, on weight of raw material
this would indicate a return of 3700 Ibs. per acre. Elsewhere a return of
4000 Ibs. per acre would seem to be also above the average.

Chemical Selection Of the Cane. — By continually selecting for
seed beets of high sugar content, the richness of that plant in sugar has been
greatly increased ; a similar process is not possible with the cane owing to its
asexual process of propagation. The records of more than one experiment
station contain accounts of attempts to improve the cane by the selection of
cuttings from sweet canes, but the earlier results were inconclusive and con-
tradictory. Definite results have been obtained by Kobus13 in Java, who thus
summarizes the results of his experiments : —

"Different stalks of the same sugar cane plant vary widely in sugar
percentage even when they are of the same age. Consequently we founded
the chemical selection on the analysis of the juice of the whole plant and not
on that of single cane stalks.

" The variability of sugar percentage of various sugar cane varieties is
very different. Those grown from cane seeds do not vary so much as the old
varieties.

"The juice of the heavier plants is richer in sugar than that of the
lighter ones, and those plants that have the richest juice are the heaviest.
Plants grown from cuttings derived from canes rich in sugar are heavier and
contain more sugar than those grown from average plants or from plants poor
in sugar.

"When we select the richest canes from the descendants of canes that
were already rich in sugar, and also the poorest canes from the descendants of
poor canes, and go on in this way for some years, we very soon arrive at a con-
siderable improvement in the rich canes (40 per cent, in five years) and a heavy
depression in the descendants of the poor ones (60 per cent, in five years).
The descendants of cuttings grown from once selected canes remain richer in
sugar for at least four generations, and show as an average of forty experiments
only a very small decrease.

" The correlation of a high sugar percentage in the juice and a heavy
weight of cane plant simplifies the method of selection in a remarkable way.
It is sufficient to select those 20 per cent, that are the heaviest, i.e., the
strongest tillered plants of the cane field and plant the cuttings of one-half of
these, viz., of those richest in sugar.

125

CANE SUGAR.

"We proved that differences in the juice of the descendants of rich
and of poor canes are already visible at an age of thirty weeks, and that it is
possible to perform the selection at that age in the fields we use in Java for
the propagation of cane cuttings. Highly selected canes of twenty weeks did
not show any difference in^the juice of the rich and the poor plots."

Field Ledger. — A sugar plantation being often a self-contained unit
affords a unique opportunity for the systematic accumulation of valuable data
which in a few years form a valuable guide ; such data may conveniently be
entered in a ' Field Ledger,' using one double page to each field and one line
to each year or crop ; such a ledger should contain columns for entering up the
following data, the exact mode of bookkeeping followed being governed by
local considerations : — Year ; rotation (plant or ratoons, green crop, &c.) ;
variety ; tons of cane and sugar per acre ; % sucrose in cane and purity ;
nature of soil ; cultural operations ; prevalence of pests and diseases ; manure
applied ; lime applied ; agricultural and fertility (citric acid) analyses of soil ;
inches of rain and irrigation water ; mean temperature ; date of planting,
harvesting and period of growth ; date of arrowing.

EEFERENCES IN CHAPTER VIII.

1. I. S. J., 66 and 67.

2. Stubbs' Sugar Cane, p. 113.

3. Dept. of Land Records and Agric. Madras II. , p. 202.

4. Stubbs' Sugar Cane, p. 145.

5. Southern Agriculture, pp. 128-135.

6. S. C., 314.

7. Cultur de la Canne a Sucre, p. 129.

8. Bull. 25, Agric. H.S.P.A.

9. Loc. cit., 3, supra, 10.

10. 7. S. J., 68.

11. S. C., 294.

12. 8. C., 346.

13. I. S.J., 90 and 91.

126

CHAPTER IX.

THE PESTS AND DISEASES OF THE CANE.*

The cultivation of the cane is in many places one continuous struggle
against its pests and diseases ; this is so much so that the time of many experi-
ment stations is occupied in studying and devising remedies against the cane's
enemies. Within the limits of a manual such as the present only the fringe of
the subject can be touched on ; more complete details will be found in Van
Deventer's l Die dierlijke Vijanden van Tiet Suikerriet op Java,1 in Went and
Wakker's 'Die Ziekten van net Suikerriet op Java,' in the 'Memoirs of the
Department of Agriculture in India,' in the West Indian Bulletin, in the
Sugar Cane and International Sugar Journal, in the Java Archief and in the
Bulletins of the Hawaiian Sugar Planters' Association.

Abnormalities in Canes.— Peculiar canes with aborted joints, with
a superabundance of eyes, with absence of eyes, with excessive development
of the woody tissue, and with albino leaves, are sometimes noticed; the
phenomena have little interest other than academic. Some varieties show
these features more frequently than others, and the writer's clinical observa-
tions lead him to think that temperature variation may be a predisposing cause
for these abnormalities.

Weeds particularly connected with the Cane.— Certain
weeds have been noticed as associated with the cane, though their presence is not
in any way directly connected with the cane. Amongst these may be men-
tioned a succulent herbaceous annual Alectra Irasiliensis, whose roots penetrate
the cuticle of the cane and destroy it. This weed has been named the ' cane
killer' in Trinidad. In India a weed, Strigea lutea, and similar to the
'broom rape,' is known as a frequent inhabitant of cane lands ; the 'lantana,'
a woody shrub belonging to the Verlenacece, is known throughout the tropics
as a pestilent plant, rapidly taking over land temporarily abandoned ; it is
particularly obnoxious in Mauritius and the Hawaiian islands. In the latter
district it has been controlled by Koebele in an elegant way, namely by the
importation of sundry insects -with a specialized habit of feeding on the leaves
or of ovipositing in the flowers and seeds.

Mammalian Pests. — Excluding purely isolated cases of occasional
damage by the larger animals, it is only rats, hares and jackals, that can be
regarded as cane enemies. Rats are cosmopolitan in their distribution, and
not only destroy cane, but also cause considerable damage to parapets and
drains. Hares are known as a cane pest in India and in Mauritius, in the
latter place their depredations being considerable. Jacknls are confined to

*Kirkaldy (Bull. 8, Ent. H.S.P.A.) has given recently a complete bibliography of cane
pests, enumerating in all 400 species noted as attacking cane.

127

CANE SUGAR.

India where the Chinese cane (Saccharum sinense) is said to be so hard as to
resist their teeth.

Liepidopterous PestS. — The Lepidoptera (moths and butterflies)
that may be classed as cane pests fall into two main divisions, those that cause
damage by the caterpillar eating the stalk, and those where the leaf is selected
as a food material ; in addition certain Hicrolepidoptera attack the cane,
principally at the eye. In the Hawaiian Islands these last are known as
'bud worms.'

The stalk-eating caterpillars are known as 'borers';* they are of wide
distribution, and annually cause immense damage. Following on their mode
of attack they are classed as 'top,' 'stem,' and 'root' borers; in Figs. Ij.3
and ^4 are given after Kruger diagrams illustrative of the mode of attack
of a stem and of a top borer.

FIG. 43.

FIG. 44.

Below is given a list of the known cane borers, included in the Lepidoptera.

TOP BOBERS.

Scirpophaga auriflua. The white borer of India.

Sc. mono stigma. The black spotted borer of India.

Sc. intacta. The white borer of Java.

Sc. chrysorrhoea. India.

Chilo infuscatellus. The yellow borer of Java.

Grapholitha schistaceana. The grey borer of Java.

* The term borer is also applied to several coleopterous (beetle) insects attacking the
cane, and mentioned subsequently.

128

FIG. 15.
BLACK

TANNA.

2
3

SIZE

PLATE VIII

THE PESTS AND DISEASES OF THE CANE.

STEM BORERS.

Diatraa saccharalis. The West Indian borer.

D. striatalis. The grey stem borer of the East Indies and Australia.

Chilo auricilia. The gold fringed borer of India.

C. simplex. India.

Nonagria uniformis. The pink borer of India.

Anerastia ablutetta. The green borer. India.

Castnia licus. The large moth borer of South America.

Sesamia nonagrioides. The purple borer. Java, East Indies, Spain,

Portugal, North Africa, Madeira, Mauritius, Madagascar.
BOOT BORER.

Polyoclia saccharella. India.

All these borers have a very similar mode of attack ; the female moth lays
its egg on the leaf of the cane ; the caterpillar, on emergence, attacks either
the stem, generally at the eye, or else the terminal point, and eats its way
into the cane. When in the cane it often tunnels the whole length of the
stalk ; eventually the perfect insect emerges from the cane.

When young cane shoots are attacked, especially by the top borer, the
death of the stalk, results ; in older cane, especially when attacked in the stem,
the damage may not be so complete.

The Borers have been studied in great detail in many cane growing
districts; full accounts of those that occur in Java are given by Kruger1 and
Yan Deventer.2 Maxwell Lefroy3 has described the West Indian Borer,
and the Borers as they occur in British India4 ; Oliff5 has described the Borer
of New South Wales, and Bojer6 the Borer in Mauritius.

A short account of the West Indian Borer, as described by Maxwell
Lefroy,3 is appended, as typical of these pests : —

" . . the eggs are flattened oval, and slightly convex, about -^ of an inch
in length ; they are laid in clusters on the leaf of the cane, the number being very
variable, lying between 4 and 57, and being generally from 10 to 30. The eggs
when fresh are light yellow ; in 36 hours a tinge of orange appears, and eventually
they turn orange brown ; in the final stage the centre of the egg becomes black.
If the eggs are laid on young cane the part attacked is the axil of the leaf or the
leaf itself ; in the case of older cane the part attacked is the joint, the caterpillar
eating its way into the cane, and making tunnels up and down the cane, from which
it eventually emerges in from 30 to 35 days. The period of pupation, which takes
place within the cane, is six days, after which the perfect insect emerges. The
moth is inactive by day, and living only four days lays in that time from 100
to 300 eggs."

In Figs. 1±5 and £6* are shown the larva and moth of the Borer Diatraea
xtriatalis, and in Figs. 47 and 4$* the larva and moth of Sesamia nonagroides.
The eggs of the first-mentioned are shown in Fig. 49* ; at a are fresh eggs,
at b eggs just before emergence of the caterpillar, at c and d are eggs parasitized
by Ceraphron leneficiens and Chactosticha nana. Fig. 50* shows the quite different

* See Frontispiece.

129

CANE SUGAR.

egg mass of Scirpopliaga intacta ; all these are after Van Deventer. The
leaf-eating lepidopterous pests, are neither in the extent of their destructive-
ness nor in the permanency of their attack to be compared with the Borers ;
their attack seems to be sporadic and to rise and fall with many factors. Thus
the * army worm ' (Leucania unipuncta) is known to attack cane and corn after
floods which have forced it to leave its usual habitats. The damage is chiefly
to young cane, the leaves and not the stem being attacked ; except in severe
cases the cane recovers, and suffers only a temporary check in growth.

Coleopterous Pests. — The Coleoptera (beetles) are equally destruc-
tive with the Lepidoptera, and, as with the latter, it is chiefly the larvae that do
the harm, although in some cases it is the perfect insect that attacks the cane.
The term ' Borer ' is also applied to some of the beetles, and in fact, in the
Hawaiian Islands, this term is confined exclusively to the ' Weevil Borer '
(Sphenophorus obscurus) ; an allied insect, S. sericeus, is also known as a Borer
in the "West Indies.

Amongst the major coleopterous pests of the cane attention may be called
to the Walwalan Beetle (Apogonia destructor] of Java, the West Indian Root
Borer (Diaprepes abbrematus), the Cane Grub (Lepidoderma alboliirta} of
Australia, the Louisiana Beetle Borer (Ligyrus rvgiceps], and the Weevil
Borer (Spenophorus obscurus) of the Hawaiian Islands, Fiji, Australia, and
New Guinea. The damage done by the first four above-mentioned pests is due
to the larva, which passes its life underground, eating the roots ; the fifth is
a stern borer. Figs. 51, 52, and 53* after Yan Deventer, show a piece of soil
containing the grubs and the larva and perfect insect of Apogonia destructor.

The life history of the West Indian Root Borer has been worked out by
the Rev. N. B. Watson,7 whose description of this pest is appended : —

" In August and September the perfect insect lays its eggs on the upper surface
of the leaves, and after ten days the grub emerges and falls on the ground,
immediately burrowing into the ground in search of food. The grub remains in
the soil for 312 days, eating the roots of cane, sweet potato, &c., and then pupates,
the perfect insect emerging in fifteen days to repeat the same cycle. The grub at
first is only ^ inch long, reaching at maturity a length of one inch.

In Fig. 5Jj* is shown the Weevil Borer, and in Fig. 55* a typical piece of
damaged cane. The life history of this insect as it occurs in the Hawaiian
Islands is thus given by Koebele8 : —

" The female beetle is easily separated from the male by its longer, smoother,
and more slender beak, and its pointed terminal segment. She lays her eggs con-
secutively, probably four to eight each day, but less than this toward the end of
the period of six or eight months during which she continues to lay. When the
egg is laid in the cane from the outside, this is done from under the sheath, which
the beetle can brace against; with the prominent saw-like movable teeth laterally
she first begins to eat out the hole until softer ground is struck, so to speak, when
she will force the work, moving the head up and down as well as sideways until the
whole length of the beak is buried. Upon soft parts on split cane this operation

* See Frontispiece.

130

THE PESTS AND DISEASES OF THE CANE.

takes from 1£ to 2 minutes; no doubt much longer in boring through the hard
epidermis, probably hours. After the hole is completed the beetle walks up and
inserts the ovipositor, remaining in this position from 4 to 6 minutes. The bone
coloured egg is found embedded parallel to the fibres. It is about 2 mm. long "by
| mm. in thickness and slightly bent. The hole close to this is filled in with
mucous matter intermixed with particles of fibre. Repeated observations show
these eggs hatch in six days. The newly-hatched larva is at first transparent as
the eggs of the latter production, the first being of a more opaque colour as also the
young larvae, with the head of a darker yellow colour. We found that the young
larva went out in the same direction as fibres about one-eighth of an inch deeper,
having made a hole one inch long in from four to five hours. As the larva
increases in size its power of boring becomes more rapid. A half grown specimen
traversed a piece of cane eix inches in length, from one end to the other, in three
days."

Other coleopterous pests of less importance are the ' Bibit Kever,' i.e.,
cane top beetle (Holanaria picescens), the mature insect of which attacks the
eyes of the cane when used as seed, and several ' Leaf Miners ' such as
Hispella wakkeri, the larvae of which feed on the cane leaves.

The well-known and widely distributed ' Shot Borer ' beetle (Xyleborm
perforans] perhaps confines its attention to dead and damaged cane and is not
to be regarded as a serious pest.

RhyncotOUS Pests. — The Rhyncota are a great order of insects
characterized by the development of the mouth parts into an organ known
as the beak or rostrum, adapted for the sucking of vegetable and animal
juices ; the phases of insect life known as lice, blights, blast, scale and bugs
(in its English sense) include many insects of this order. A large number
(upwards of twenty in Java alone) have been noted as cane pests. Several
historical epidemics of the cane have been due to the Rhyncota, and of these
may be instanced that of the Cane Fly (Delphax saccharirora) in the "West
Indies in the beginning, that due to the pou-cL-poche-llanche* in Mauritius,
about the middle of the nineteenth century, and that in the Hawaiian Islands
due to the Leaf Hopper (Perkinsiellia saccharicida) at the beginning of the
twentieth century. To these may be added the more recent epidemic of
the Frog Hopper (Tomaspis posticata) at present (1909) prevalent in Trinidad.

Although individually these insects are very small, yet the numbers in
which they occur, and the rapidity with which they multiply is the occasion
of great damage ; for these same reasons they are indifferent to any but the
specialized means of control described below.

In Fig. 56] is shown a leaf of the cane infected by an aphid (Aphis sacchari)
and is illustrative of the great numbers of these, and of allied pests, that may
be present in a small space.

* The true pou-d-poche-blanche is a cpccid (fcerya scychellarum) ; a second coccid ( Pulvinaria
iceryi) was also present in the original Mauritius epidemic. The term pou is also applied
to a mealy bug (Dactylopius calceolaria) ; this pest has also been confounded with the white
louse of Java (Oregma lanigeri) which is however an aphid and entirely distinct.

t See Frontispiece.

131

CANE SUGAR.

Orthopterous Pests. — The Orthoptera do not include any of the
major pests of the cane ; the one of this order that causes most damage is
probably the Mole Cricket9 (Scapteriscus didactylus) in Porto Rico where,
besides attacking cane, it is a general plant enemy. The fully developed
insect is about 1£ inches long. The damage done to cane is by the attacks of
the perfect insect in search of food. The greater part of the life of the insect
is passed underground feeding on the roots of cane and other plants ; it
emerges at night, and then feeds on the crop above ground. Its attacks
continue the whole year round. It has been observed to attack plants con-
tinuously, and beyond the demands of its appetite. This insect committed
great damage in S. Vincent about 1830, and in Porto Rico became a dangerous
pest in 1876, after the destruction by a hurricane of its most effective enemy,
the blackbird, this forming an interesting illustration of the effect of distur
bance of the ' natural balance.' Its damage is greatest in moist sandy soils ;
in dry soils it does not thrive, and saturation and extreme dryness are condi-
tions inimical to its development.

Another Mole Cricket (Gryllotalpa africand] in the Hawaiian Islands not
only injures the cane directly, but also does considerable damage to the
irrigation ditches by means of its tunnels.

Amongst other pests of this order 'may be mentioned the white ants
(Termes taprobanes] of India, which, according to Hadi, attack the cuttings of
seed cane and less frequently the young shoots shortly after germination. The
insects known as * thrips ' or ' bladder feet,' which are sometimes included
in the Orthoptera, are also known as a pest of the cane in Java.

Acarid Pests. — Mites are a form of life frequently found on canes ;
the damage done to the cane is, however, in general small. A serious amount
of damage was done in Queensland in 1876 by a mite, Tarsonymus bankroftn10 ;
the disease was then known as ' Cane Rust ' ; this mite is also present in Java,
where it does a certain amount of damage, and has also been noted in Barbados.
Mites may also be considered as beneficial, since Ormerod11 has observed the
parasitization of the eggs of the West Indian Borer by this form of life.

"Worms. — Certain nematode worms have been connected with cane
damage, particularly the varieties Heterodera javanica and Tylencus sacchari in
Java. They have also been much studied by Cobb,12 but that they are to be
•classed as a cane pest is doubtful.

Control of Cane Pests. — The control of cane pests is mainly
-divided into two parts — their systematic destruction by methods referred to
below, and the prevention of their introduction from foreign countries by a
strict system of quarantine. The methods q£ systematic destruction employed
vary with the pest, and below are some accounts of the principal systems
in use.

132

THE PESTS AND DISEASES OF THE CANE.

1. Poisons. — The use of poisons is practically limited to the destruction
of rats. The poisons chiefly employed for this purpose are preparations of
strychnine, arsenic, phosphorus, and barium ; bread, grains, bananas, and
molasses are used as food media upon which the poisons are distributed.

Leaf-eating caterpillars are in some instances destroyed by dusting the
leaves of the plants upon which they feed with sundry arsenical preparations,
of which those known as ' Paris Green' and « London Purple ' are mostly
used. Leaf-eating caterpillars are not amongst the most serious pests of the
cane, and in practice it would be impossible thus to control them on a large
estate.

2. Collection by Hand. — In districts where labour is plentiful and cheap,
a diminution of the insect pests is obtained by hand collection. This collection
takes the form of cutting out the ' dead hearts,' i.e., the young cane attacked
by borers, and the collection of the eggs of the moth laid on the leaves of the
cane. The children of the black or Asiatic labourers forming the bulk of the
labour supply of most sugar producing districts can readily be trained to perform
this work. In the collection of eggs it is of importance that the parasitized

FIG. 57.

eggs be not destroyed. Following the advice originally given by Zehntner the
eggs should be placed on a dish surrounded by a layer of molasses ; the parasite
from parasitized eggs emerges as a perfect insect and is able to escape, the
molasses preventing the escape of the caterpillar from the unattacked eggs.

The night-flying coleopterous and lepidopterous insects can be captured
by exposing lamps in infected areas ; these lamps are exposed over trays of
molasses which prevent the escape of the insect. For the capture of the
Wawalan .Beetle (Apogonia destructor} of Java, Zehntner2 has devised the
trap shown in Fig. 57, which is exposed under a lamp at night during the
time that the beetles make their nuptial flights.

The employment of bait as a means of attracting insects is also in vogue
in the Hawaiian Islands, and in Fiji it has been observed that the Weevil
Borer is attracted by sour cane; Koebele3 records that in Fiji, with the
help of seven little Indian girls, he has thus collected 16,000 beetles in four

133

CANE SUGAR.

hours, and that there systematic collection over three years resulted in the
almost complete disappearance of the pest. Similarly, S. M. Hadi13 states that
the white ant is in India attracted by dung which is purposely placed on the
cane fields as a means towards the collection and subsequent destruction of the
insects.

3. Rotation of Crops. — This has been recommended by Watson7 as likely
to diminish the prevalence of the West Indian Root Borer (Diaprepes
abbreviatus), and amongst crops not attacked he mentions ochra, cassava, yams,
eddoes, woolley pyrrol, pigeon pea, bonavist and rouncival beans.

4. Use of Substances objectionable to Insects. — Wray states that cane tops
soaked for a few minutes in water tainted with petroleum are not attacked by
ants, and S. M. Hadi13 mentions the use of mustard cake and assafcetida by the
ryots of India for a similar purpose. Naphthalene9 has been used similarly to
impregnate the ground to repel the mole cricket in Porto Rico.

5. Use of Insecticide Washes. — Spraying as a means of the destruction of
insects is only effective with small crops grown on a restricted area, and has
but a limited use with the sugar cane. It has been employed chiefly in
•connection with hemipterous pests, such as the Aphis and Mealy Bugs. leery,
in Mauritius, employed a wash formed by boiling lime and sulphur as a means of
destroying the pou-a-poche-blanche ; the most generally employed insect wash
is a petroleum emulsion made according to the following formula : —

1 part soap, 10 parts water, 20 parts petroleum ; the soap is dissolved in
hot water and the petroleum slowly added to the hot solution with constant
stirring. A creamy mass results, which for use is mixed with 15 parts of cold
water. On the small scale this solution is distributed from a knapsack spray
with a hand pump ; power sprayers conveyed in carts are also in use, but the
writer believes their employment is confined to the fruit industry carried on
over comparatively limited areas.

Extract of pyre thrum is a widely used insecticide, and is thus prepared 14: —
Genuine Persian or Dalmatian insect powder, 100 grms. ; raw spirit,
200-250 grms.; 80-100 grms. ammonia; allow to stand for two days.
Dilute with two litres of water and allow to stand exposed to the sun for a
few more days ; filter through a cloth, squeezing out the residuum well. The
dark brown liquor is extract of pyrethrum. Use 25 grms. of this and
25 grms. of soft soap per litre in aqueous solution.

6. Flooding. — The flooding of fields has been proposed as a means of
destroying the larvae of those insects that are subterraneous in their habits.

7. Destruction of breeding Places. — Many of the parasites of the cane
utilize trash, dead cane, &c., as breeding -places, and following this the
destruction of all refuse likely to harbour insects has been advised ; agri-
culturally this process leads to a loss of nitrogen, and Perkins has observed
that the burning of trash, &c., may at times be ill-advised, as the leaf hopper
is able to escape by flight, a faculty not possessed by all its parasites.

134

THE PESTS AND DISEASES OF THE CANE.

8. Quarantine of imported Plant Material. — It is certain that many of the
serious epidemics of insects are due to their accidental importation unaccom-
panied by the natural enemies that keep them in check in their original
habitat. Instances of these introductions are numerous. The 'Borer' was thus
introduced into Mauritius in 1848 15 in a consignment of cane received from
Ceylon. Orders were given to destroy the cargo, but it is supposed that
some ill-advised person secretly removed and planted a few tops. The intro-
duction of canes from abroad also accounts for the Weevil Borer and Leaf
Hopper in the Hawaiian Islands. It is of great interest to note that evidence
exists that the borer of these islands was introduced from Otaheite along with
the original Lahaina cane (cf. Chapter TV.)] it was on the "Pioneer" estate
at Lahaina that it was first noted a year or two after the introduction of the
cane there. Another boring pest of the cane, Sesamia nonagrioides, originally a
North African species, has now become widely distributed over the tropics.

When the immense damage done by insects is recollected (in the Hawaiian
Islands alone the leaf hopper in one year destroyed cane equal to not less than
60,000 tons of sugar), any expenditure on a proper system of quarantine can
only be regarded as a rational policy of insurance. Such a system is now
established in the Hawaiian Islands.

9. Infection with Disease. — A number of years ago it was proposed to
destroy rats by means of bait infected with cultures of the organism Septicaemia
muris ; the first essays in this direction were not attended with success, but
more lately favourable reports have been received of the efficacy of ' Dansyz
virus ' as a muricide ; the use of this has, of course, been chiefly developed in
connection with the prophylaxis of plague.

A number of micro-organisms are parasitic upon insects ; thus the death
of the weevil borer has been observed as due to the mould Penicillium glaucum ;
a fungus, Isaria barber i, is also known as parasitic upon the caterpillar of the
West Indian moth borer, and a species of Botrytis upon the caterpillars of the
moth Psalis securus in Java. The help afforded by these fungi does not appear
to be very great. The destruction, however, of the scale louse Aleyrodes
longicornis by a fungus Ascherontia aleyrodis in Florida has been noted by
Webber16 apparently acting with good effect.

10. Encouragement of natural Enemies. — The increase of many pests is
often traceable to a decrease in the number of their enemies ; an example of
this is the great increase of the mole cricket in Porto Rico in 18769 after the
destruction of the avian population of that island in a hurricane. Amongst the
insectivorous animals which may be classed as friends of the cane are birds,
lizards, newts, toads, ladybirds and spiders. In this connection Dr. Perkins
informs the writer that the destruction of the ' grass army worm ' in the
Hawaiian Islands is due largely to the mynah bird, an introduced species.

11. Parasitization. — If the checks on insect multiplication were removed
agriculture would be impossible. To the great majority of insects are attached

135

CANE SUGAR.

one or more parasites, and it is due to the absence of the parasite that the
sudden outbreaks of insect damage are due. The control of insect damage is to
be obtained by the introduction, breeding and distribution of approved parasites.
A striking example of this method is afforded by the work of Koebele, Perkins,
and their associates in the control of the leaf hopper pest in the Hawaiian
Islands. This insect was introduced unaccompanied by the parasites which in
other places kept its development in check ; expeditions were sent to Fiji,
Queensland and elsewhere, parasites were obtained, bred and distributed, and
the leaf hopper was in a few years placed under control ; this achievement may
well be considered as a classic in economic entomology. The parasites found
to be the most effective were extremely minute hymenoptera, belonging to the
Calcididae, of which Paranagrus optabilis, P. perforator and Anagrus frequens
were the most valuable. These parasites lay their eggs on the eggs of the leaf
hopper, and this form of parasitization is considered the most effective.

Very often cane pests are kept in check by naturally occurring parasites ;
thus a species of Chrysopa, belonging to the neuroptera, controls the ' spittle
fly,' Delphax saccharivora, in the West Indies. In Java, the detailed studies of
Zehntner, Yan Deventer and others have brought to light many parasites ; the

* moth borers ' are thus controlled there chiefly through the agency of two
minute chalcid hymenoptera, Ceraphron leneficiens and Chaetosticha nana ;
other of the pests in Java (and doubtless elsewhere) are controlled by other
minute hymenopterous insects which may be well considered as amongst the
most beneficial of their kind. In Figs. 58 and 59* are given, after Yan
Deventer, a drawing of Ceraphron beneficiens, and the eggs of the 'Borer,'
Diatrcea striatalis, parasitized by this insect.

Amongst other beneficial insects may be mentioned various * ladybirds '
( Coccinellida) to which the control of aphis and other 'plant lice' is largely due.

It may also be mentioned that the planting of certain plants, e.g. Pigeon
Pea (Cajanus mdicus), Bonavist Bean (Dolichos lablab\ near to cane fields has
been stated to attract the hymenopterous insects parasitic on many cane
enemies.

The question of pest control by parasites and predators is, however, a
most complicated one, and includes many factors grouped together in the term

* struggle for existence? Thus there may be a major pest of the cane, A, and
a minor pest, B, which is also predatory on A. Amongst these may be intro-
duced a third form of life, C, parasitic on A, which in its turn is parasitized
by D, which also includes B among its hosts. It is only by the careful study of
the life history of the pests and of their parasites, and by taking into account all
conditions, that it can be determined if the introduction of such and such a
form of life is advisable ; the ill considered disturbance of the natural balance,
as instanced by the results of the introduction of the mongoose into
Jamaica, is unreservedly to be condemned.

* See Frontispiece.

136

THE PESTS AD DISEASES OF THE CANE.

For a detailed study of the control of insect pest by insect parasite
reference may be made to the detailed account of the leaf hopper in the
entomological bulletins of the Hawaiian Sugar Planters' Association.

Froggat17 however, has very severely criticised the pest control work of
Koebele and Perkins, and is inclined to attribute the diminution of the leaf
hopper to the burning of trash, (a custom which had been in vogue for a
generation previous to the appearance of the hopper), and which Perkins
indeed does not advise since the hopper can escape by flight, whilst the
parasites are unable to do so. A change in the variety of cane planted is also
given by Froggat as tending to have controlled the hopper, but although on
some plantations hard rinded varieties were hurriedly planted during the
first period of the epidemic, this alone had little effect, and plantations which
made no change obtained an effective control by means of parasitization.

On the other hand, Silvestri,18 who also studied the conditions locally,
writes in the highest terms of the work of Koebele and Perkins, and considers
that there is no doubt of the economic success of insect pest control through
the agency of their parasites.

Insect Epidemics. — In the preceding pages reference has been made
to several historic insect epidemics ; in many of these there is strong evidence
that the epidemic was due to external introductions and these may then be
classed as instances of the disturbance of the natural balance. In one instance,
at least, an epidemic was probably due to wilful neglect of warning and to
disobedience of State orders. The losses suffered by Mauritian planters, about
1850, from the borer should be sufficient to warrant the introduction of new
varieties of cane only under a well advised system of inspection and quarantine

Insect epidemics may however arise from uncontrollable causes, as
instanced by the present (1910) serious aspect of the spread of the Giant
Borer (Castnia licus] in British Guiana19. This insect was first noticed as
casually attacking cane about 1901 on the East Coast of Demerara ; in 1904,
it was reported as doing great damage to cane at ' Enmore ' in that district ;
previously its food habits were only connected with the roots of an orchid
growing near the Upper Orinoco. As this insect is known from Central
America to the Amazon, it probably was not a recent introduction, but
suddenly for obscure reasons developed the faculty of feeding on the cane.

Although the presence of an active State entomologist would not have
influenced the development of the habits of this insect, yet the reporting to
such an official of the first observed damage in 1901 would have allowed him
time to study its life history, to have warned planters of the imminent
danger, and to have devised means for its control.

In any community dependent on agriculture for its prosperity, a depart-
ment of economic entomology is necessary ; the losses due to preventable
epidemics would pay the expenses many times over ; whether the officials of
such a body should be the servants of the State or employes of a private

137

CANE SUGAR.

association is debatable ; means for the enforcement of its recommendations
are necessary however, lest the carelessness of a few individuals destroy the
whole object of its existence.

Fungus Diseases.* — The diseases due to fungi are numerous and
collectively cause annual losses of enormous sums ; they have been studied
amongst others by Kriiger, "Went and Wakker in Java, by Howard and
Lewton-Brain in the West Indies, by Cobb in Queensland, by Cobb and
Lewton-Brain in Hawaii, by Barber and Butler in India, and at Kew by Massee.

The most prominent diseases are the Sereh of Java, the Rood Snod of
Java, which is cosmopolitan and is best expressed in English as Red Rot of the
Stem, the Rind Fungus of West Indies, the etiology of which is still imperfect,
the Black Smut and Top Rot, the cosmopolitan ' pine-apple disease,' Cobb's
Gumming disease, and various so-called root diseases, most of which appear to
be due to basidiomycetous fungi. In what follows an attempt is made to
collate some of the more important points.

Leaf Diseases. — The leaf diseases of the cane are numerous and
wide-spread, but none are very dangerous ; they have been chiefly studied in
Java and more lately by Butler in India ; comparatively little attention has
been paid to them elsewhere.

1 . Djamoer oepas. — Large brown patches occur on the leaf and sheath,
caused by a silvery mycelium found on the surface, the haustoria of which
penetrate into the leaf, especially on the underside, and on the interior of the
sheath. Later, small bodies (sclerotia), first white, then yellow, and finally
brown, are observed on the dead portions of the leaf ; these spots are the size
of a grain of mustard; the leaves attacked soon wither and die, but the
damage is unimportant.

2. Yellow Spot Disease.™ Cercospora kopkei. Krtiger. — This disease
occurs as dirty yellow spots, often meeting to form one irregular blotch,

the centre of which becomes red. A
brown mycelium is found on the leaf,
the branches of which, sometimes isolated,
sometimes united in bundles, carry colour-
less spores ; the appearance of the under-
side of the leaf is as if covered with

* 270

YIG. 60. a white dust. The damage is not great.

The technical description of this fungus is : — Cercospora kopkei. Maculis
amphigenus, sinuosis confluentibus purpureo brunneis infra palidoribus, margine
concolori ; hyphis plerumque hypophyllis fasicudatis, septatis apice noduhsis,
denticulatisque fumoso bruneis 40 — 50 X 7 conidiis fusoideis suberectis 20 — 50
x5 — 8wiedie 40x6 utrinque obtusiaculis 3 - 4 septatis non constrictis passum
guttulates subhyalinis. Various forms of the spores of this disease are shown

in Fig. 60.

* See note in Appendix.

138

THE PESTS AND DISEASES OF THE CANE.

250

FIG. 61.

3. Leaf Spot Disease. Pestalozzia fusescens var. sacchari. Wakker. —
This fungus forms irregular spots on the leaves with a withered centre and
brown border ; it is a rare and unimportant disease.

4. Cane Rust.'2'1 Uredo kuhnii. Wakker and Went. — Narrow orange
coloured stripes appear on the leaf, especially on the underside, and from these

stripes an orange coloured rust can be
scraped ; this serves to distinguish
the fungus from other leaf fungi of the
cane. The rust is composed of the
spores of the fungus. Kriiger des-
cribes this fungus as Uromyces kuhnii.
In Java the disease is everywhere
present in damp districts, but the
damage done is small. The technical
description is: — Uredo Icuhnii. Soris
uredo aporiferis hypophyllis linearibus;
uredo-sporis e globoso ellipsoidiis v
pyriformilu*, contentu aurantiaco exosporio copiose aculeate hyalino 18— 34-' 5 X
28- '5— 57' 5 ; pedicellio hyalino clavato suffultis. Various forms (after Kriiger)
of the spores of this fungus are shown in Fig. 61.

5. Eye Spot Disease.™ Cercospora sacchari. Yan Breda de Haan. —
The presence of the disease is indicated by small red dots, which grow into
long elliptical dark red spots, with

a light yellow margin; at a later

stage the centre becomes a dull dead

yellow, surrounded by a dark red

area, and this is circumscribed by a

bright yellow border ; the elongated

elliptical shape of the spots, which

may grow up to 1^ to 2 inches in

length, is retained ; the appearance

of the spots is not dissimilar to the

eye on a peacock's wing. With a

pocket lens hairs (conidiospores) may

be seen growing from the leaf. The disease has been observed in Java and

in Hawaii ; in Java it does not appear on Cheribon cane or in mountain

plantations, and in Hawaii it only makes much progress in wet weather ;

varieties differ much in susceptibility. The technical description of this

fungus is: — Cercospora sacchari. Hob. in foliis, qua maculantur, sacchari

oficinarum. Hypha pluriseptatce, brunece, 120— 60 ; conidia 60 — 80x9 — 12 ;

vermicularia 5 — 8 septata Irunea. Forms of the spores of this fungus (after

Cobb) are shown in Fig 62.

139

CANE SUGAR.

1200

6. Ring Spot Disease.™ Leptospharia tacchari. Van Breda de Haan. —
The appearance of a leaf of the cane attacked by this disease is so similar to
that caused by eye spot disease that confusion is easily possible. The
differences are that in Ring Spot the spots are seldom more than half an inch

long, and are nearly as broad as long. The
bright yellow margin observed in eye spot is
absent, and the centre of the spot is a dull
greyish white. The conidia are formed chiefly
on the under surface of the leaf ; they are three-
celled, the central cell being larger than the
outer ones, the whole spore forming an obtuse-
angled body ; at a later stage perithecia appear
on the leaf as small black spots. Each ascus
contains eight four-celled bobbin-like spores.
The spores of this fungus are shown (after
Cobb) in Fig. 63.

7. Red Spot Diseased Eriosphceria (Went.)
Coleroa (Van Breda de Haan.) Venturia (Sac-
chardo) sacchari. — This organism forms dark red
spots on the leaf, generally roughly circular,
and about 1 cm. in diameter. The connection
between the disease and the fungus has not been

proved by infection experiments. In Hawaii, it is said, spots exactly similar
to those described have been noted without any indication of the Erispharia
being present. The technical description of this fungus is : — Venturia sacchari.
Hal. in foliis sacc. offic. Perittecia 70 — 80 diam., asci 25 long; octospori,
sporidia 11x16.

8. Slack Spot of the Leaf Base.™—
A blackening of the leaf base has been
observed in Java to be due to an organ-
ism, Cercospora acerosum. The spores
are bobbin-shaped, from 2 — 3*5 microns
wide and from 10—50 microns long;
they contain from one to as many as
seven cells. These spores (after Dickoff
and Hein) are shown in Fig. 64'

9. Leaf Splitting Disease.26— This
disease, which is perhaps confined to
one district in Hawaii, is characterized

by a number of yellow stripes appearing in the leaf, which afterwards splits
and withers. Cobb considered this disease due to an organism, Mycosphcerella
striatiformam, but did not prove the connection by inoculation experiments.
Similar, and perhaps, identical diseases are known in Fiji and the Argentine.

FIG. 64.

140

THE PESTS AND DISEASES OF THE CANE.

A disease similarly characterized was described in 1849 by Bojer27 in
Mauritius, who attributed it to electrical influences in the atmosphere.

10. Yellow Stripe Disease.™ (Gele Strepen Ziekte.) — This is a leaf disease
often referred to in the Java literature, and as yet imperfectly diagnosed. Some
references show points of similarity with the ' leaf splitting' disease of Hawaii.

11. Broivn Leaf Spot.™ Cercospora longipes. — The disease due to this
organism is described by Butler as prevalent in North and South Behar;
narrow oval spots about £ inch long and of a reddish colour are the first signs of
the disease ; as the spots increase in size a brown centre becomes evident, and
at one stage of the disease three concentric rings, brown, red and yellow, are
seen ; eventually the spot become a broad oval deep brown ring, with a straw
coloured centre. The rings are usually from a quarter to a third of an inch
long by an eighth of an inch or more in breadth. The technical description of
this fungus is: — Cercospora longipes. Maculis elongatis, amphygenis, saepe con-
fluentilus, primo sangwneis, orescendo stramineis, Irunneo-cinctis ; hyphis in
caespitulos gregarios collectis, plerumque hypophyllis flexuosis, Irunneis, sursum
geniculatis vel denticulatis, 100—200 X 4 conidiis obclavatis sursum attenuatis,
rectis vel curvatis, !± — 6 septatis, 1^0—80x5 hyalinis. In Fig. 65 are shown
(after Butler) spores of this fungus.

x 130

FIG. 65. FIG. 66.

Diseases of the Leaf Sheath.

1. Eye Spot of the Leaf Sheath.™ Cercospora vagina. Kriiger. — This
disease is characterized by a brick red spot appearing on the leaf sheath;
this red colouration does not spread over the leaf sheath ; the centre of this
spot becomes eventually black. The disease is due to the organism Cercospora
vagina ; Kriiger gives the length of the spores as from 19-6—40 microns,
with an average length of 25*2 microns, and the breadth as seven microns.
In Fig. 66 are shown (after Kriiger) spores of this fungus.

2. Ited Rot of the Leaf Sheath.31 — The organism causing this disease
is imperfectly known ; the disease is characterized by the leaf sheath becoming
red, the red colouration spreading all over the sheath, and shading off into
an orange colouration. The disease passes from the leaf sheath to the stem,
attacking the soft parts near the nodes ; at a late period of development the

141

CANE SUGAR.

infected parts are covered with an abundant mucus mycelium, and eventually a
large number of sclerotia the size of a pin's head are produced ; these are first
white, and finally become yellow and brown. The diseased parts have a smell
of mushrooms. It is young cane that is most often attacked, and in the case
of tops the germination of the eyes may be prevented.

3. Add Rot of the Leaf SJieafh™ — A disease much resembling the Eed
Rot, and also incompletely diagnosed. It is distinguished by the lighter red
colour of the infected parts, by the larger sized orange
sclerotia, and by the odour of apples. The disease
does not readily pass to the stem, and then only
attacks the young internodes.

Diseases of the Stem.

1. Black Smut.™ Ustilago saccJiari. Rabenhorst. —
The organism which causes this disease is found in
all affected parts. The part of the cane most liable to
attack is the top of the young cane, which is turned
into a black, whip-like substance, covered with a
slimy foul-smelling material ; the whole stool of cane
is destroyed. The organism is found on grasses and
on wild cane, the latter in Java having been noted
as a source of infection. The disease occurs in Java,
Natal, Queensland, and India, where Butler has
observed the possibility of the disease appearing
from the use of infected tops; he does not consider
it a dangerous disease, but the writer has seen
great damage caused in Mauritius. In one case a
seven-acre field was absolutely destroyed. Butler also
observes that the fungus has a predilection for those
varieties of cane approaching wild cane. The
technical description of this fungus is: — Sorts atris :
Sports globosis sulawgulatis, 8-18 olivaceo-bruneis, vel
rufescentibus, episporio crasso levi imtructis. In Fig. 67 is shown the whip-like
appearance of the cane attacked by this disease, and in Fig. 68 spores of the
fungus.

2. Donkelan-ziehte.u Mar-
asmius sacchari. Wakker. — This
is a disease attacking the foot of
the cane, and, so far as regards
Java, appearing chiefly in nur- FIG. 68.

series. The disease is characterized by the withering of the leaves of the
young shoots, and by the non-development of the buds. The cane plants
contain in the interior a mycelium which also occurs as large white flakes
on the surface of the cane. The fungus has been studied in the West

FIG. 67.

142

THE PESTS AND DISEASES OF THE CANE.

Nat Size

FIG. 69.

Indies by Howard and Lewton-Brain. Here adult cane is usually affected,
particularly ratoons ; the roots are attacked, and the cane dies from
want of water. After rains the toadstool is often found growing at the
base of the cane. Wakker's technical description of this fungus is Gregoria

vel bati fasii-culata, diver sa, carnoso-membranacea
persistentes ; pileus albus late-campanulatus dein
sordide albus, planus vel cupuliformis, 15 mm. diam.;
lamellae albae simplices vel bifurcatae. Stipe*
centrahs albus, long. 15 mm. apice tubiforme base
villosa. HypJiae albae. Sporidia hyalina, continua^
irregulariter-oblonga utrinque atienuaia 16 — W x
4 — 5. Habitat in caulibus vivis. This organism
or one closely related also occurs in Hawaii, and
has been provisionally named M. sacchari, var.
Hawaiiensis. A marasmius is also, according to
Fulton,35 parasitic on cane in Louisiana, and is-
identified as M. plicatus, which has been observed
as a saprophyte in Java. In Fig. 69 is shown the
toadstool of this fungus as appearing in Hawaii^
and in Fig. 70 the spores, both after Cobb.

3. Top Rot or PokJca Song. — The etiology of this disease is considered
uncertain by Went and Wakker. It has been connected with Cobb's Gumming
Disease, but later researches, especially those of Erwin Smith,36 indicate that
these diseases, whilst somewhat similar in outward appearance, are totally
distinct.

Three stages may be recognized in the disease. In the first the young
leaves become yellow, wither and die, while the internodes, being unable to
obtain food, remain short and stunted ; in the second stage the young leaves
that have opened roll up and die ; in the third stage the vegetative point is
changed to a slimy pulp, the remainder of
the top being filled with a slimy substance
possessing a foul smell similar to but distinct
from that associated with the Ustilago sacchari.
Later the eyes underneath the top shoot
and may form almost a new top. Young
plants a few months old are more often
affected than mature cane, and continued
rain is a predisposing cause. On an estate
with which the author was connected in Demerara, a rot, outwardly the
same as the one in question, was very prevalent, and he made the following
observations : — Older canes frequently suffered, but there was always previous
insect damage of the top. In young canes of age from a few days (i.e., when
the eye was sprouting) to two or three months the apical leaf was frequently

FIG. 70.

143

CANE SUGAR.

seen to wilt ; on applying a steady tension this could be pulled out entire, or
in the case of a sprouting eye, the bud could be unravelled ; at the base of the
leaf a discoloured area was seen associated with a foul smell ; by examining
sprouting eyes which were just beginning to wilt, or even which were
apparently healthy, all stages of the rot could be seen ; in many cases there
was evidence of previous damage by an undetermined insect, the larva of
which (a footless grub, about T% inch long) was present ; but frequently there
was no sign of insect damage. This disease was certainly causing no
inconsiderable harm.

4. The Gumming Disease. Pseudomonas vascularum. Cobb. This disease,
which has been incorrectly associated with Top Rot, was originally
described by Cobb in Queensland. It is characterized by the exudation
of drops of gum from a cut or punctured surface, as shown in Fig. 71.

FIG. 71.

The top of the cane also becomes charged with a putrid offensive slime. Cobb
connected the disease with the presence of a micro-organism which he called
Bacillus vascularum, but did not make the complete bacteriological proof of the
connection of this organism with the disease. This has been done later by
Erwin Smith,36 who has definitely proved the connection between gumming
and Cobb's organism. An important point in Erwin Smith's research is that
he shows that the 'common purple cane' and D 74 are much less susceptible
than the 'common green cane,' and connects this with the less acidity of
the 'common green cane.' Greig Smith38 also proved that the bacillus
grown in pure culture produced the characteristic gum found in the vessels
of diseased cane. He also noted the resistance of variety to the disease.

Erwin Smith thus describes the appearance of the organism: —

The organism appears as an actively motile, short rod, and when stained
and imbedded in balsam has an average measurement of 0*4 : 1 micromilli-
metres. Carbol violet followed by dilute alcohol produces the best films ;
fuchsin stains the gum, which usually adheres more or less to the cells ; the
"blues stain but feebly. By using the night-blue method with the scanty
growth obtained on ordinary agar the flagella can be easily stained. They are
single and terminal. The bacteria are not coloured by the Gram method of
staining. Spores were not obtained and are probably never formed.

144

FIG. 16.
SALANGORE.

PLATE IX

THE PESTS AND DISEASES OF THE CANE.

Sereh.. — This disease was first recognised as such in 1882 in Java
where it has done very great harm. In the typical form of ' sereh '
the stool of cane consists of a number of short stalks with very short
joints ; the buds, especially those below, sprout, whereby results a bundle of
short stems hidden in a mass of leaves. The whole stool bears a resemblance
to lemon grass (Andropogon schoenanthus] the Javanese term for which is
' sereh? In a second type one or two stalks may grow to a fair size with very
short joints in the upper part; above all is a fan-shaped leaf crown; many of
the eyes, especially those below, sprout and form small branches. Benecke 39
has given the following symptoms of this disease : —

1. A low, shrubby growth, often only from 3-4 decimetres.

2. A fan-shaped arrangement of the leaves arising from a shortening

of the internodes.

3. The internodes are only from ^ to f inch long.

4. The nodes are tinted red.

5. Numerous aerial roots are formed.

6. The fibro vascular bundles are tinted red.

7. Subterraneous outbranchings form.

8. The sheath and root buds turn vermilion.

9. In some cases there is no formation of wax on the stem.

10. The growing part of the stalk is frequently dyed red.

11. The leaf-sheath and the stalk stick together.

12. There is an accumulation of secondary organisms.

The presence of gum in * sereh ' cane is a point about which much has
been written ; the major portion of opinion seems to be that the presence of
gum is a consequence of, and not directly connected with, the disease ; if the
gum is of bacterial origin the growth of the bacteria might only take place in
canes already weakened by disease.

A red colouration of the fibrovascular bundles is a characteristic of
1 sereh ' ; this colouration is most pronounced in the node, but often appears in
the internode in the form of a red stripe ; this appearance is quite distinct
from the red patch with white centre characteristic of the lred rot of the
stem.1

A red string of the sugar cane associated with the presence of gum has
also been described by Grieg Smith40 ; this he ascribes to the association of an
unidentified ascomycete with a slime producing bacillus, which he names
JB. pseudarabinus.

The immense amount of work that has been done on Sereh has quite
failed to elucidate the cause of the disease ; opinion is divided in ascribing the
cause to physiological and to pathological influences ; amongst the first, bad
drainage, injudicious manuring, late planting, excessive ratoonage, an
insufficiency of silica in the soil, and degenerescence have been suggested.

145

10

CANE SUGAR.

As regard parasites, Treub41 ascribed the disease to the attacks of a
nematode worm to which he gave the name Heterodera javanica. Coinciding
with the attacks of this worm he observed the presence of a fungus of the
genus Pythium. This worm penetrated the bark of the root at places of
accidental injury or at the growing point. After having arrived within the
root the worm worked its way parallel to the central axis until it arrived at
the point of growth of a lateral root. Soltwedel42 also attributed the damage
to attacks of a worm to which he gave the name Tylenchus sacchari,
stating that the parasite passed its existence in the root which it destroyed.
The length of the Tylenchus is given by Soltwedel as about '7 mm. and its
breadth as about '03 mm.

The connection between nematode worms and Sereh is not now generally
accepted.

Janse43 ascribed the cause of Sereh to two organisms,
Bacillus sacchari, and Bacillus glanga, and stated that these
organisms attack other plants besides the cane. He considered
the seat of the disease lay in the reddened nbro-vascular bundles.
The dependency of Sereh on these organisms is not now
generally accepted.

Lastly, Went attributed Sereh to a combined leaf-sheath
and root disease, caused by an organism Hypocrcea sacchari, the
description of which is as follows : —

Pulvinata dein depressa, carnosa, pallide fusca, stromatibus
2 — £ mm. lat. 1 mm. cras&is, scepe laviter collascentibus, intus
pallentibus vel albidis, pertheciis fuscis, ostiolis, vix prominulis
200 - 250 = 150 - 200, ascis linearibus breve pedicellatis
100 X 5, sp'>tidiis monostichis 8, e cellulis duabus incequalibus
mox decedentibus compositis, cellula superiori globosa 4- diam.,
cellula inferiori cuboidea oblonga 6 x -4, fumose-olivaceis, conidiis.
Verticillium sacchari.

In Fig. 72 is shown (after Went) an ascus of the Hypocraaa,
°* ' containing eight spores. Latterly the idea seems to be taking

hold that Sereh was the manifestation of peculiar soil and cultural conditions,
the various micro-organisms associated with it only becoming prominent
after the health of the cane had become affected.

A point of great interest with this disease is the difference of opinion a&
to its infective nature ; the disease certainly spread from district to district in
Java, but conversely healthy sticks planted in an affected field remained
healthy. Whether infectious or not, the disease was found to be hereditary :
that is to say, canes planted from sound healthy seed gave healthy canes, but
tops derived from sereh struck canes became equally infected.

146

THE PESTS AND DISEASES OF THE CANE.

The localization of the disease to Java, or its presence elsewhere, is of
great importance ; in the literature references may be found to its appearance
in Australia, Mauritius, and Reunion ; the only authoritative statement I have
come across is due to Went, who saw Black Java canes in Surinam with the
symptoms of the disease. The writer himself has not infrequently in Mauritius
and Demerara seen canes presenting the symptoms of sereh, including the red
stripe ; it is admitted that such symptoms may be present in sereh-free canes,
and these symptoms appearing in other than sereh canes may account for the
great diversity of opinion as to the cause of the disease.

6. Red Rot of the Stem." Colletotrichum falcatum. "Went.-— The Red
Smut has been carefully investigated by Went. He says that diseased
plants do not show any outward sign of disease so long as they are not
seriously affected. At a later stage the plant dies away, the leaves becoming
prematurely withered and yellow. On cutting the cane longitudinally the
joints are found to be affected, but two consecutive joints are seldom diseased.
The disease shows itself in the shape of a red colouration in the interior of the
joint, which is unequally distributed and darker in one place than another ;
peculiar white spots are also to be seen. This appearance serves to distinguish
the disease from Sereh, which is marked by a red stripe. The rind is un-
aftected, and since the fibrovascular bundles are chiefly congregated near the
rind, the leaves are still able to obtain their food.

In the white blotches a mould is always present, a few threads of mycelium
being found in the red patches. In the vascular bundles brownish-black
patches also occur, connected with which is a mycelium flourishing in the cells
and walls of the bundles.

If a piece of diseased stem be allowed to dry, black streaks appear, due to
stromata, from each of which spring a number of brownish-black straight
hairs measuring from 100 /A to 200 u in length and 4 JLL wide. Among these
hairs arise a number of sickle-shaped conidia, measuring 25 p, by 5 /*. If the
diseased cane be kept in a damp place a white mycelium turning to grey
appears, forming, in a few days, chlamydospores or resting spores. Went never
obtained any form of spores other than conidia or chlamydospores. To the
organism described above he gives the name Colletotrichum falca'um, and states
that it is a wound parasite, only attacking canes already injured by insects.
The organism has also a selective power for different varieties of cane. The
complete description by Wrent of this is : Colletotrichum falcatum. Setis num
seriatis, nunc in pseudo-conceptaculum congregatis cuspidatis, 100—200x4.,
fulgineis, sursum pattidioribus, conidiis falcatis 25=4, hyalinis, ad hasim setul-
orum, lasidiis ovoideis 20 x 8, hyalinis vel fuscts, suffultis. Habitat in culmis
vivis. This organism is cosmopolitan. More recently the fungus has been
studied by Lewton-Brain,46 who has shown the existence of an enzyme
secreted by the fungus, to which the loss of sugar is due.

147

CANE SUGAR.

In Fig. 73 is shown from a photograph (after Lewton-Brain) canes
attacked by this fungus, revealing the characteristic white spot in the centre of
the red coloration, and in Fig. 74- the spores of this fungus.

FIG. 73.

7. Pine-apple Disease.*5 Thielaviopsis ethaceticus* Went. — The Ananas
or Pine-apple disease is, like the last-mentioned, a wound parasite, and its
favourite place of attack is the exposed ends of cuttings for seed cane ; fully
grown cane is rarely affected. When a cutting is attacked, the interior
at first becomes crimson red and then black, at the same time giving off a

* See note in Appendix.
148

THE PESTS AND DISEASES OF THE CANE.

pleasant odour reminiscent of pine-apples. A fungus, Thielaviopsis ethaceticus,
was found by Went to be the cause of the disease. Cultures made from diseased

X600

Fio. 74.

canes remain white for from twelve to twenty-four hours and then turn olive-
green ; this colour is due to macroconidia situated in the special cells at the ends
of short branches of the mycelium. Microconidia are also formed in chains of

149

FIG. 77.

CANE SUGAR.

three or more. They are forme I within the top of a hypha and are rect-
angular and colourless. The complete description of this fungus is thus given
by Went : — Thielaviopsis. Hypliae steriles hyalinae vel pallide fuscae, septatae.
HypTiae fertiles septatae non ramosae. Macroconidia ovata,
fusca, catenulata, mox secedentia. Microconidia cylindracea
vel bacillaria, hyalina, in interiore hypharum catemulatim
generata et mox ex apice exsilientia. T. ethaceticus.
X 325 Macroconidia 16 — 19 X 10 — 12, microconidia 10 — 25

FIG. 76. =3,5 — 5, in interiore hypharum 100 - 200 ^ long.

Habitat in culmis, fructibus, foliis in imula Java. This organism is
cosmopolitan.

In Fig. 75 are shown photographs of sound canes and of canes attacked
l3y this fungus ; in Figs. 76 and 77 are shown the macro-and micro-spores.

8. Cytospora sacchari.29 This organism has been
observed by Butler, probably as a parasite of sugar
•cane in India; canes attacked resemble those attacked
by rind fungus, and it is stated by Butler to be pro-
bably of only minor importance.

The technical description of this fungus is: — Cytos-
pora sacchari. Butler. Stromatibus verruciformibus seriatim ordinates,
subcataneo-erumpentibus, plurilo-cularibus, nigris, osteolo elongato,
£ |?^ 8wgulo reiriis, duobus praeditis ; sporulis minutissimis, cylindraceis,
curvulis, utrinque obtusis ; 3~5 X 1'5 microns; basidiis ramosis
septatis, 12 — 18 microns. Hob. in culmis vaginisque sacchari
officinarum India.

In Fig. 78 are shown (after Butler) the spores of
this fungus, and in Fig. 79 a part of the diseased stalk.

9. Diplodiacacaoicola.^ P. Henn. — This organism,
which is known chiefly as a disease of the cacao tree
and pods, was observed by Howard in the West Indies
to be also parasitic on the cane. The appearance
of canes attacked by this organism is similar to that
occurring in attacks of rind fungus. Affected canes
have a shrunken appearance, and on the rind appear
little pustules, from which hairs eventually exude ; in
dry weather the hairs do not appear, the spores showing
as a blackish crust on the outer surface of the cane.
Howard succeeded in infecting canes with pure cul-
tures of this organism, which has also been observed

by Butler29 on cane in India. The technical description of this organism
is : — Pustulis prominalis nigris sporulis oblongis breniculeatis ; cirri's nigris
12 X 5.

x 580.

FIG. 78.

Natural Size

FIG. 79.

150

THE PESTS ANTD DISEASES OF THE CANE.

In Fig. 80 is shown (after Butler) a cane stem attacked by this fungus,
and in Fig. 81 the spores, also after Butler.

10. Black Rotc*g . Sph&roncema adiposum. Butler. — An organism described
under this name has been found by Butler in India, associated with Thielaviopsis
ethaceticus, and Butler has succeeded in infecting healthy canes with this
organism. His description of it is: — Sphceroncema
adiposum. Mycelio dense lanoso, atro ex hyphis brunneis,
ramosis composite ; hyphis fertilis simplicibus, septatis,
endoconidiis gerentibus ; endoconidiis polymorphis,
cylindraceis, pyriformis vel globosis, aliis hyalinis vel
brunneis, Zevibus, aliis fuscis verrucosis, 9—25x fa 5 - 18 ;
peritheciis globosis, pilosis, atris in cottum erectum,
rigidum, 2—6 m.m. X 50 microns, productis, ore sub-
fimbriatis; sporidiis hyalinis, continuis, crasse lunulatis,
utrinque acutis 6'5 X 3'5, muco adiposo obvolutis. Sab.
in culmis sacchari officinarum, India. Fig. 82 shows
a cutting infected with this fungus.

11. The Maladie de la Gomme, or Gumming
Disease of Mauritius, has been described, as far as
external appearance is concerned, by Boname. At
first there is nothing abnormal in the appearance of
the cane, but when the disease ia fully established
growth is stationary and the leaves turn yellow. If the stem is cut trans-
versely, small masses of a yellow viscid matter appear on the cut surface,
which dry and harden in the air. This gum is only found in the central fibro-
vascular bundles, and not in the sacchariferous cells. A
gum, however, which is not yellow is also found round
the knots and on the upper portion of the stem. In the
final stage of the disease the extremity of the stem
decays, the internal portion being filled with a grey
viscid substance.

x 250

FIG. 81.

Diseased specimens of canes were forwarded to
Prilleux and Delacroix,49 who found on these canes an
organism which they identified with Coniothryrium
melasporum. This organism is the same as Darluca melas-
porum, found by Berkeley on Porto Rican canes, and is
indentified by Howard with the Dipljdia cacaoicola. The
description of Boname agrees very closely with the
appearance due to gumming as described by Cobb, and
it is, of course, possible that the organism found by

Prilleux and Delacroix was in a sense accidental, and not the cause of the

disease.

/Yafural -S/2t

FIG. 82.

151

CANE SUGAR.

12. The Rind Fungus of the West Indies. — By Bind Fungus in the
"West Indies is meant the black pustules and hyphae that appear on the rind
of dead and damaged cane ; it is thus described in the Kew Bulletin.50 : —

11 Canes infected with rind fungus are first noticed by dark red or brown
patches in one or two joints toward the middle or base of the cane. This
red patch having made its appearance rapidly spreads upwards and downwards,
the infected area darkens in appearance, and is evidently rotten. Little black
specks make their appearance between the joints, breaking from the inside to
the surface."

Specimens of affected canes were examined by Massee, who considered the
disease to be due to a sphaeriaceous fungus which he named Trichosphaeria
sacchari, and he found macro-conidia in the interior, and micro-conidia on the
wounded surface of the cane. Both these forms he obtained in flask cultures
inoculated with stylo-spores.

Went thought that Massee' s macro-and micro-conidia belonged to the
fungus T. ethaceticm, and suggests the identity of a saprophyte of cane,
known in Java as Melancomum sacchari, with the fungus producing the black
pustules and Massee's sphaeriaceous fungus.

Howard,5 in Barbados, investigated the connection between the
Tricosphaeria, the Melanconium and the red smut (rot). His experiments and
results may be briefly summarized : —

1 . On canes attacked by rind fungus two organisms are always found —
a Melanconium and the Colletotrichum falcatum of Went.

2. The Melanconium inoculated into living cane does not produce rind
fungus, the damage being confined to the dead cells around the wound.

3. Canes infected with Colletotrichum falcatum reproduce all the
features of rind fungus.

4. When canes are infected with Colletotrichum falcatum and after-
wards with Melanconium spores, the latter grow.

5. The Melanconium always follows attacks of Colletotrichum falcatum,
but does not itself attack living cane.

It is to be noted that Howard treats the popular term ' rind fungus ' as
synonymous with the Java * rood snod.' This is unfortunate, as the ' red
smut ' is essentially a disease of the interior of the cane.

The Melanconium fungus is one that has been much studied, and other
investigators do not treat it altogether as a harmless species. Cobb37 describes
it as 'cane spume,' identifying it with Strumella sacchari. He says, "I
believe it is true that in most cases, if not all, this fungus requires the cane
to be first in some way injured. Perhaps the frost so injures the arrow of the
cane as to cause it to decay and die ; perhaps a borer makes its way into the
cane, and thus breaks the rind ; or, again, perhaps the wind twists the stalk
and cracks it, or the cane gets injured in any of the numerous possible ways;

152

THE PESTS AND DISEASES OF THE CANE.

then this fungus stands ever ready to take advantage of the accident, and in a
few weeks' time makes such an inroad as to send the whole cane well on its
way to decay. . . . The amount of damage done by spume is difficult to
estimate. There is no doubt that through its agency much cane, which
though injured would be saleable, is soon rendered worthless."

As a result of further study in Hawaii, Cobb treats this fungus as strictly
parasitic, and mentions that it is a frequent cause of the non- germination of
cuttings used for seed.

Lewton-Brain52 also treats the fungus as parasitic ; his studies have
indicated that the Melanconium is unable to penetrate the hard outer rind of
the cane, but that when introduced through a wound, in a susceptible cane, it
can enter the thin- walled cells, and bring about the death of the cane. He
does not, however, regard it as markedly parasitic on varieties at present
widely cultivated.

The literature of ' rind fungus ' is very confused, but may be thus briefly
summarized.

Howard treats rind disease as synonymous with the red smut of Java,
caused by Colletotrichum falcatum.

Cobb and Lewton-Brain treat rind fungus as a disease caused by Melan-
conium sacchari, and Howard does not regard this organism as parasitic.

The planter, when speaking of rind fungus, refers to the appearance of
black hairs growing out from a diseased cane ; this appearance may be caused
by the Melanconium sacchari, by Diplodia cacaoicola, or by Cytospora sacchari,
and most often follows on attacks of other diseases.

Lewton-Brain calls the disease caused by Colletotrichum falcatum ' red rot
of the stem,' thus distinguishing the disease from the red rot (rood rod) applied
by Went and Wakker to a disease of the leaf sheath.

The organisms associated with the well-known appearance of rind fungus
have been described under different names, and we have Trichosphceria sacchari —
Melanconium sacchari — Strumella sacchari and Darluca melasporum — Conio-
thryrium melasporum — Diplodia cacaoicola.

In the writer's opinion, the etiology of ' rind diseases ' still remains
obscure ; those who have been unfortunate enough to have seen ' rind disease '
at its worst in Demerara, the West Indies, or Mauritius will require much
convincing that this appearance is not connected with an aggressive parasite ;
experiments with the Melanconium seem to prove that this form is not parasitic.
On the other hand Howard has shown the parasitic nature of Diplodia cacaoi-
cola on cane in the West Indies ; an outbreak of ' rind disease ' was observed
by Harrison53 in the experimental plots at Georgetown, British Guiana ; on
the affected canes Howard found the Diplodia ; on Mauritius canes examined
by Prilleux and Delacroix the same organism was found. All this seems to
point to the Diplodia as being the aggressive parasite, and the cause of rind
fungus, to the exclusion of the Melanconium.

153

CANE SUGAR.

Fig. 83 shows a cane attacked by the Melanconium, and Fig. 8!j. shows the
spores.

FIG. 83.

The Root Diseases of the West Indies.— This disease was
shown by Howard to be due to the fungus Ifarasmms saccJiari ; in Java this
is considered as a disease of the stem, the basal part of which is attacked ; the
roots of the cane also suffer so that the term * root fungus ' is justified ;

FIG. 84.

whereas in Java the disease is chiefly prevalent in nurseries, in the West
Indies it is general and is particularly severe on ratoons. The disease is
marked by the stunted appearance of the canes, by the dry leaf strap sticking
to the basal end of the cane, by the presence of the mycelium which can be
seen with the naked eye, and after rainfall by the appearance on the stalk of
small fan-shaped toadstools.*

* In Demerara the writer has seen canes die with all the outward signs of ' root
disease ' ; the toadstools which appeared under favourable conditions of rainfall were not
in any way like those of AJarat'mius; they were umbrella-shaped, with stipe 3-4 ins. long
and with cap £-1 inch wide.

154

THE PESTS AND DISEASES OF THE CANE.

Root Fungi. — Under this term (Wortel Schimmel) there have been
described in Java three fungi characterized by a growth of mycelium under-
ground associated with the cane roots ; the first of these was described by
Treub as a Pythium, and considered by him as a cause of Sereh ; later work
by Wakker did not confirm this identification or connection. Wakker54 further
described two root fungi — Cladosporium javanicum and Attantospora radicola —
as frequently occurring in cane fields but does not 'regard them as parasitic.
Of similar habit is the Ithyphallm coralloides stated by Cobb to be the cause of
a root disease in Hawaii ; later work has not confirmed Cobb's views on the
parasitic nature of this fungus, though some evidence exists that the under-
ground mycelial strands interfere to some extent with the development of the
cane roots. In the Hawaiian islands it is a matter of common knowledge that
the Ithyphallus is often abundant on the most productive fields.

The Control of Fungus Diseases.

1. Use of healthy, selected, disease-free seed for planting. — This can
be effected by careful selection, or by growing seed cane in nurseries
remote from infected areas, or by using for seed cane from that part
of a plantation which is observed to be the least disease affected, and rigidly
rejecting for seed purposes any cane from parts of the plantation that are
known to be infected with disease. The presence of red fibre is, according to
Cobb, a sure sign that the cane is not disease free.

2. Use of fungicide wastes on the seed. — The exposed ends of cane
cuttings form a most convenient point of entry for fungus spores, particularly
the Thielaviopsis ethaceticus, and it is this organism that is largely responsible
for the non-germination of cuttings and the consequent expenses of
' supplying.' It has been shown by the experiments of Howard in Barbados,
of Cobb in Hawaii, and of others, that soaking the cuttings in Bordeaux
mixture preparatory to planting is a very efficient prophylaxis.

Bordeaux mixture is prepared as under : —

Dissolve 6lbs. crystallized copper sulphate in 25 gallons of water.
Slake 4 Ibs. of quick lime in 25 gallons of water.

Gradually add the lime water to the copper solution, with constant
stirring ; when completely added, test the mixture by immersing in it for a few
seconds a bright steel blade ; this should not become coated with a red layer
of metallic copper ; but if the blade becomes coated more lime must be added.

The time during which the cuttings should be left to soak is half an hour.

In addition to soaking in Bordeaux mixture, the protection of the cut ends
with tar has been proposed.

3. Isolation of diseased areas and patches, and destruction of fungus in
these areas by heavy dressings of quicklime. This was recommended by
Howard, Lewton-Brain, and Cobb, in connection with the various root fungi.

4. The adoption of all means likely to result in a diminution of flies is
also recommended by Cobb, as he has shown how these insects are responsible

155

CANE SUGAR.

for the distribution of the spores of the Ithyphallus coralloides. The dissemina-
tion of typhoid, cholera, and dysentery by means of flies is now well recognized ;
in these cases the flies visit human excreta, and carry the causal organisms to
unscreened food and drink.

5. Destruction of dead cane, and of trash, as such material forms a habitat
for certain organisms parasitic on living cane.

6. Rotation of crops. — The peculiar proneness of the cane to disease lies
perhaps in the wide-spread practice of growing it continuously on the same
areas; similar observations with regard to wheat grown continuously at
Rothamsted have been quoted in Chapter VI. It is, perhaps, the various
forms of ' root disease ' which are most helped by this system. If other crops
not susceptible to the fungi attacking cane were grown in rotation, the fungus
would be starved, and would tend to disappear ; as it is, the fungi have often a
continuous habitat, and the soil becomes infested. Similarly lack of hygiene
may lead to houses and districts becoming infected with pathogenic organisms.

7. Selection of immune varieties.— The work of Experiment Stations has
been largely directed to this end ; and already seed varieties are grown on the
large scale where, owing to the prevalence of disease, older varieties such as
the Bourbon and White Transparent quite failed. An interesting point in con-
nection with immunity is Erwin Smith's failure to infect the cane D 74. with
the Pseudomonas vasculaium (Cobb) to which 'gumming' is due. The Yellow
Caledonia, or "White Tanna, in Hawaii is also to be noted as a disease -resistant
variety. In Java, the Sereh disease was, and is, controlled almost entirely by
the selection of immune varieties.

In certain cases immunity may be connected with hardness of rind.

8. Avoid all processes, such as high trashing, that tend to injure or to
expose the softer parts of the cane.

9. Inspect and disinfect all canes received from foreign countries. This
process of quarantine can also be extended to a self-contained cane-growing
district in some areas of which disease is known to be more prevalent than mothers.

The Ccnnection between Pests and Diseases.— When 'rind
fungus ' was prominent in the "West Indies in the nineties, great attention was
paid to the possible sequence of disease on insect damage. This view has now
become generally accepted ; to many diseases the hard outer rind of the cane
acts as a partial barrier.

Disease Epidemics. — The history of the cane abounds with
instances of sudden and destructive disease epidemics. In Reunion, during
the years 1845-1851 a yellow cane — qui n'etait autre que la veritable
Otaheite™ — was so attacked that it was necessary to entirely replace it with
other canes ; this epidemic spread to or appeared simultaneously in Mauritius,
and is the one to which Darwin refers in his Variation of Animals and Plants
under Domestication, mentioning the substitution of a red cane (probably the
Belouguet or Black Cheribon) for a white cane (probably Otaheite). This

156

THE PESTS AND DISEASES OF THE CANE.

disease, which at this time it is hopeless to attempt to identify, was
characterized by a ' cork-screwing' (tire-bouchonnage] of the top, a 'yellowing off '
and drying up ; the authority quoted above states that it is on record that the
canes showed signs of degenerescence for fifteen years previous to the epidemic.*
About 1865, the Louzier cane (cf. Chapter IV.) originated per saltum in
Mauritius and there is evidence that this cane is the Otaheite, or staple cane of
these islands, previous to the epidemic of the forties ; for a generation this
cane remained the standard cane of Mauritius, and again in the nineties it
suffered from a maladie. This disease has been discussed above. Here then
exists a case of a cane twice forming the standard in a space of fifty years,
and twice being almost exterminated by disease ; in the second epidemic relief
was obtained by the planting of the Tanna canes.

Other disease epidemics are known ; in Madeira and Natal the Uba cane
has replaced one which had become diseased ; in Australia the ' gumming '
disease has assumed epidemic form ; the Rind fungus (the etiology of which
is still not altogether satisfactory) of the nineties in the West Indies, and the
Sereh disease of Java, so ably controlled by the plant-breeding work of Kobus
and others, are well known instances. Though these epidemics are due to
micro-organisms, yet the action of these is accentuated by, and perhaps may be
initially caused by, negligence of plant hygiene. Quite recently Harrison56 has
struck a warning note when he writes: — "I have personally never
favoured the readiness so apparent of late years to refer almost every
instance of decreased yield in cultivated plants to the noxious action
of microbes or fungi. It appears to me that for a long time back
we have in the tropics rather neglected what I may call the physical and
chemical hygiene of our cultivated soils, and have not paid sufficient attention
to the soil-conditions which may have materially reduced the naturally

resistant powers of plants to the attacks of bacteria and fungi And

further, I think that the susceptibility of certain kinds of plants, for instance,
the Bourbon cane, to injury by drought and fungus attacks is due in part at
least to the defective conditions of soil hygiene under which, in places, they are
now cultivated."

REFERENCES IN CHAPTER IX.

1. Das Zuclcerrohr.

2. De dierlijke vijanden van het suikerriet.

3. W. I. B., I., 327.

4. Agric. Jour, of India, April, 1908.

5. Agric. Gaz., N.S.W., 1893, 373.

6. S. <?., 44-51.

7. W. L £., IY., 37.

8. H. P. M., Nov., 1900.

9. Porto Rico Agric. Exp. St., Bull. 2.

*May not this degenerescence have been due to the gradual infection of both seed and
soil due to the use of infected tops ?

157

CANE SUGAR.

10. 8. C., 255.

11. 8. a, 146.

12. Butt. 6, Path. H.S.P.A.

13. The Sugar Industry of the United Provinces of Agra and Ou.de.

14. 8. O.t 303.

15. S. C., 44.

16. U.S.D.A., Bull. 13, Div. of Plant. Path.

17. Official report on Fruit-Fly and other Pests in various Countries, N.S.W.

18. Haiuaiian Forester and Agriculturist, VI., 287.

19. U.S.D.A. Bull. 54, Div. of Entomology.

20. Medeelingen v.h. Proef Station, West Java, 1890, 113.

21. Loc. cit., 20, XIII.

22. Loc. cit., 20, XVI.

23. Loc. cit., 20, 1893, 25.

24. Loc. cit., 20, 1893, 22.

25. Arch., IX., 1015.

26. Bull. 5, Path. H.S.P.A.

27. Trans. Roy. Soc. Arts and Sc., Mauritius, 1849.

28. Arch., I., 216.

29. Mem. Dept. Agric., India Bot. Ser., I., 3.

30. Loc. cit., 20, 1890, 64.

31. Arch., II., 954.

32. Arch., IV., 853.

33. Loc. cit., 20, 1890.

34. Arch., III., 597.

35. Bull. 100, Louis. Univ. Agric. Sep. Station.

36. CentrnlUatt fiir Balderiologie, 13, 729.

37. Plant Diseases and their Remedies, N.S.W., 1893.

38. Proc. Lin. Soc., N.S.W., 27, 31.

39. 8. C., 252.

40. Loc. cit., 38, 29, 449.

41. Medeelingen uits Lands Pantentium, 1885, II.

42. Tijdschrift voor Land en Tuinbouw en Boschculture, 1887 and 1888.

43. Mededeelingen uits Lands Plantentium, 1891, VIII. and IV.

44. Die Zielden van het Suikerriet, p. 36.

45. Loc. cit., 44, p. 44.

46. Bull. 8, Path. H.S.P.A.

47. Arch., IV., 209.

48. I. 8. J., 41.

49. Bull. Soc. My col., XL, 80.

50. Keiu Bulletin, 1895, 81.

51. I. S. J., 53.

52. Bull. 4, Path. U.S.P.A.

53. Rep. Bot. Gdns., B. Guiana, 1901.

54. Arch., IV., 368, 889.

55. Anonymous Articles in Revue Ayricole de la Reunion, 1901.

56. W. I. B., IX., 36.

158

CHAPTER X.

THE HARVESTING OF THE CANE.

Cane Cutting". — At the time of writing the author is unaware of any
admittedly successful means of cutting the cane crop except by manual labour ;
the tools used are the machete or cutlass, views of which are shown in Fig. 25.
Some of the attempts at improved methods may be briefly mentioned here1 : —

Paul devised an oscillating knife about 30 inches long, driven by com-
pressed air ; Lewis employed a small circular saw ; in these devices a portable
engine works an air compressor connected by tubing with the tool which is
light enough to be carried by one man; the engine follows the operators
through the field. The Hilton Bravo device is shown in Fig. 85; electric
power is employed in this case, power being transmitted to the saw by means
similar to that employed in the grinding tools of dental surgeons.

Of the larger power devices, that of Chivers and
Hopkins utilized a circular saw, and those of Luce,
Gaussiran, and Sloane circular knives; all of these are
based on the principle of wheat harvesters and none
of them attempted to top the cane. Cockerell's device
was an endless chain connected to two traction engines
on opposite sides of the field; the chain was dragged
across the field by the engines and was at the same time
moved in a horizontal plane.

Cane Cars. — A number of years ago the majority
of cane cars were constructed with fixed ends and sides
made of angle iron ; the successful adoption of mechanical
train unloading necessitated a change in design. In the
Hawaiian islands the cars used are either as shown in
Fig. 87 (PLATE X.) with drop sides, which on being let
down form a platform bridging the space from the track
to the sunken cane carrier, or else are plain flat cars with
sides formed of removable standards ; the track is in this
case close enough to the carrier to dispense with the
necessity of bridging with the drop side. In Mauritius and in Cuba much
cane is transported in thirty-ton steel cars on main line standard gauge
track; such cars are seen in Fig. 96 (PLATE XIII.).

FIG. 85.

159

CANE SUOAK.

Cane Loading. — In most districts the crop of cane after being felled
is altogether carried to the carts or other containers by hand ; the nature of
the cane fields is often such that it is impossible to bring conveyances on to
the field, and economy is only obtained by well-considered schemes in the
laying out of the plantation roads and portable track. In the Hawaiian
islands, the sleds shown in Fig. 86 (PLATE X.) are frequently used to convey
the canes to the cars.

Cane loaders or transfers consist essentially of a crane or derrick which
may be portable or stationary. The Wheeler- Wilson loader is shown in
Fig. 87; it is operated by means of a gasoline (petrol) motor; the cane is
loaded into slings which are elevated by the crane and dumped into the cars.

There are loaders of several designs essentially similar to the above ; some
are arranged to be moved on a portable track, and others are drawn about the
fields by horse or mule power ; it is in Louisiana that they have been mostly
developed.

Instead of using slings, loaders of similar
action to the one described above are made,
provided with grabs similar to those originally
devised for the loading of hay. A sketch of
the grab is shown in Fig. 88. It consists of
a curved pair of forks cc ; the system is sus-
pended at a by a wire rope ; a second rope is
attached at I ; a pull on the rope at I causes
the forks to open ; the grab is then lowered
on to a pile of cane, and the rope at I being
slackened a pull on the rope at a lifts the
grab with its load of cane ; to manipulate
cane two or more forks are arranged on a
beam suspended from the end of the crane. •

A totally different device, which the
writer does not believe has ever been ex-
tensively adopted, consists of a portable
endless belt conveyor arranged at an angle
of about 60 degrees from the vertical ; the
canes are loaded on to the lowest part of the conveyor, and, being carried
upward, fall from the highest point of the belt into trucks placed so as to
receive them.

In all the designs mentioned above it is necessary to bring the cane to
the loader, even to a certain extent in the case of the portable derrick ;
devices have been designed to rake the cane within a certain radius right up
to the lifting device, but such schemes have not been attended with very great
success.

160

PLATE X.

FIG. 86.

FIG. 87.

PLATE XI

FIG. 89.

THE HARVESTING OF THE CANE.

In Fig. 89 (PLATE XI.) is shown a method of transferring a cart-load of
cane to a railroad truck by means of a fixed derrick ; this view which shows
a load being lifted is taken on a Cuba plantation, and a similar method is in
use in the Elawaiian Islands.

The mechanical handling of the cane then resolves itself into schemes
for the economical transfer of the cane from the field to the receptacles intended
for its transport ; such complete mechanical harvesting as has been achieved
with grain crops does not obtain with the cane.

TRANSPORT OF CANE.— The methods adopted for the trans-
port of cane from the field to the factory may be thus summarized: —

1 . Animal power on roads.

2. Animal power on tramways.

3. Animal power on canals.

4. Mechanical traction on roads.

5. Mechanical traction on light railways.

6. Mechanical traction on public railways.

7. Aerial ropeways.
$. Pluming.

Animal Road Traction. — This method is now only used on small
properties or in larger ones as a means of bringing the cane to a central loading
station. The capacity of a mule on the roads usually to be found on planta-
tions is about one-half ton of cane at a speed of two miles per hour ; oxen are
frequently used, and a typical team and load is shown in Fig. 90 (PLATE XII.).

Animal Tramway Traction. — Below are given data comparing
the cost of mule transport on roads and on tramways.2

A tramway was constructed two miles long of two-foot gauge with rails
weighing 14 Ibs. per yard; the average load in each car was 1900 Ibs., the
train load averaging 11-25 tons ; this was drawn by two mules at a little over
three miles per hour ; the capacity of a mule on a tramway may then be taken
at from fifteen to twenty times its capacity on a road.

The initial cost of the tramways, cars, and stock was $1 5, 900, and of the
•carts and stock necessary for road transport $15,000. The saving due to the
decreased number of animals and carters was $22'75 per day, the cane trans-
ported in the same time being 240 tons.

Animal Canal Transport.— This method of transporting cane is
used to the exclusion of other methods in Demerara and the Straits Settle-
ments, where the estates are intersected with canals dug for this purpose.
The punts used in Demerara are flat-bottomed receptacles, constructed out of
-wrought-iron plates with heavy wooden bottoms ; they are about 25 feet long
by 8 feet wide and 3 feet deep, and hold from 2'5 to 3 tons of cane ; a mule

161

11

CANE SUGAR.

will haul four of these punts at a rate of from two to three miles per hour.
Water carriage is also employed in parts of Louisiana and of Australia.

Mechanical Road Transport.— Where good roads exist traction
engines form a cheap and efficient means of transporting cane. In Fig. 91
(PLATE XII.) is shown a view of such a scheme. An engine weighing
6 tons and of 20 H.P. will haul 20 tons of cane at a rate of three miles
per hour.

Mechanical Tramway Traction.— Undoubtedly the most im-
portant and efficient means of transport is a system of light railways. The
gauge adopted generally lies between 2 and 3 feet ; a gauge of 2 feet 6 inches
is one very commonly employed, but for large properties it is more
advantageous to have a gauge of not less than 3 feet, as otherwise the number
of wagons required becomes excessive. With such a gauge wagons having a
platform area of 50 square feet can be used ; such wagons will hold from 2£
to 3 tons of cane, a perfectly safe rule being to allow half a ton of cane to
every 10 square feet of platform area. A locomotive weighing approximately
15 tons will haul, at a rate of ten to twelve miles per hour, twelve to fifteen
wagons, each holding about 3 tons of cane.

The cost of laying down a system of railways to feed a factory is very
considerable. The lowest cost per mile for a gauge of 2 feet 6 inches is not
less than £300, with rails weighing 18 to 20 Ibs. per yard. For a 3-foot
gauge, with rails 25 Ibs. to the yard, an initial cost of £450 is the lowest
which can be expected. These figures do not, of course, include the cost of
locomotives and rolling stock. The cost of laying down the rails is entirely
dependent on local conditions ; where these are favourable, and no expensive
cuttings or bridges have to be made, a minimum cost of £100 per mile may be
sufficient, an estimate to be greatly increased with unfavourable local con-
ditions.

The following figures, taken from actual practice, will give much
information regarding light railway transport : —

Acreage served . . . . 2050.

Miles of permanent track 48.

Gauge 3 ft. l£in.

Number of locomotives 6.

Weight of locomotives 15 tons.

Number of wagons 175.

Size of wagons 10 ft. by 5 ft.

Load of wagon . . . . 2*75 tons.

Number of wagons per train 10.

Cane transported per 24 hours 900 tons.

Average distance of transport 4 miles.

Cane transported during crop 48,000 tons.

162

THE HARVESTING OF THE CANE.

Coal burned per ton mile 4' 70 Ibs.

Maintenance of line and rolling stock per ton mile . . '772 pence,

Fuel per ton mile 1-536 „

Stores per ton mile '160 ,,

Labour per ton mile *740 ,,

Total cost of transport per ton mile 3*208 „

On all the larger plantations in the Hawaiian islands 30-ton locomotives
are used, capable of drawing a load of 300 tons of cane ; a typical cane train
is shown in Fig. 92 (PLATE XII.).

Transport on Public Railroads.— In districts where the cane
forms an essential staple of commerce the tracks of the public railroads are
frequently utilized to transport large quantities of cane, and this method is
very efficient ; it is used very successfully in cane-farming districts, the farmers
bringing their produce in carts to a siding where the cane is weighed and then
transferred to the wagons running on the main line tracks.

This system is used extensively in Mauritius ; the wagons used are
similar to those seen in Fig. 96, and hold from 15 to 30 tons of cane.

The rates charged there for transport are 10 cents of a rupee per ton per
mile for the first, 8 cents for the second, and 6 for the third and following miles,

Aerial Ropeways. — As a means of transport in hilly or broken
districts, notably in Mauritius, ropeways find some use. The following des-
cription of the ropeways often used in Mauritius is after Wallis Taylor : —

"The arrangement consists of a driving gear at one end or terminal of
the line fitted with a driving drum suitably geared to receive rotary motion
which, in this instance, is provided by the power of the cane mill, and a
similar wheel at the other end fitted with tightening gear, an endless band of
wire rope being mounted on these wheels. At intervals of about 200 ft,
intermediately between these terminals the rope is supported on pulleys-
mounted on posts at a suitable height to enable the carriers to clear all inter-
vening obstacles, and to a certain extent also to regulate the general level of
the line. The carriers hang from the rope and are enabled to pass the
supporting pulleys by means of curved hangers. These curved hangers axe
pivoted on V-shaped saddles resting on the rope, the saddles having malleable
cast-iron frames fitted with friction blocks to enable the requisite friction on
the rope to be obtained, and allow the carriers to pass with the rope up steep
inclines and over the pulleys, wings at each end of the saddle frames embracing
and passing over the pulley rims. The saddle frames are besides each fitted
with two small wheels mounted on pins which admit of the carrier being
removed from the rope at the terminals, and at curves, on to shunt rails held
in such a position that when the carrier approaches the terminal the small
wheels will engage on it, and running up a slight incline lift the friction clip
saddle from the rope and enable it to pass to the loading or unloading station

163

CANE SUGAR.

164

THE HARVESTING OF THE CANE.

or round the curve wheels, the impetus derived from the speed of the rope
being sufficient for the purpose of enabling the carriers to free themselves
automatically from the rope."

Views of this scheme are shown in Fig. 93, and a view of the cradle in
Fig. 94.

FIG. 94.

The cost of this system to transpurt 10 tons of cane per hour is roughly
£150 1 per mile, f.o.b., European ports.

FIG. 95.

In some cases the configuration of the land will allow of a gravity
system ; in the simplest arrangement the loaded cradles run down a fixed
rope and are afterwards packed back to the fields; in another system the
descending load works an endless rope which also carries back the empty
cradles.

165

CANE SUGAR.

. — Fluming is a method of transport used to a very consider-
able extent in the Hawaiian Islands. A flume consists of a wooden gutter of
V section. The material used is pine lumber, 1 in. X 14 in., and for ease of
transport is made in 12ft. lengths ; vertical boards 6 in. high are fixed above
the gutter. It is supported on light wooden frame work, and ends directly
over the end of the conveyor carrying the cane to the crushers. The canes
are carried down the flume by means of a stream of water. In Fig. 95 is
shown a view of such a flume. Approximately 1,000,000 gallons in 24 hours
will flume 1 0 tons of cane per hour.

Cane Unloading1. — The problem of unloading the cane is a far easier
one than that of loading and has been successfully solved in many designs ;
the appliances used may be divided into those where the load of cane is
Jioisted bodily from the car, and those where the load is raked from the car.

In the hoisting class, steel chains are placed across the floor of the car,
the canes being loaded lengthways across the chains ; when the car is in a

FIG. 98.

position to be unloaded the ends of the chain are pulled out by a hooked rod,
battens being placed along the sides of the car to facilitate this ; the ends of
the sling are then joined and attached to the wire rope of a hoist ; the load is
lifted and transferred by a travelling crane over a platform or hopper ; a pull
at a rope opens the attachment of the sling, when the load of cane is dis-
charged. This form of unloader has been used by the Link Belt Engineering
Co. of New York. In Figs. 96 and 97* are shown photographs of the
installations at Carracas and Francisco plantations, Cuba. In Fig. 96 the
canes in slings are shown ready to be dumped into the hopper ; the hoisting

* See Plates XIII. and XIV.

166

THE HARVESTING OF THE CANE.

yoke is now parallel with the centre line of the shed ; on being transferred by
the travelling crane over the cars it is capable of being turned through an
angle of 90°. In other factories the position of the cars, with reference to
the centre line of the shed, is at right angles to the position shown in Fig. 97 ;
the hopper into which the canes are dumped is shown in the same illustration.
A third modification also used by this Company dispenses with the hoist
altogether. Slings are placed in the car, as before. The cars are furnished
with drop sides, so that a continuous platform to the hopper is provided. The
end of the sling, remote from the hopper, is attached to a wire rope passing
over a pulley block fixed to the roof of the shed. The car is anchored to the
ground, and a pull on the hoisting rope rolls the load of cane into the hopper.

FIG. 100.

In Fig 98 is a diagrammatic view of this arrangement ; a is the hoisting rope
receiving power from the sprocket wheel g ; b is the free end of the cane
sling ; c is the counter-weight rope, and d the counter-weight box ; / is the
operating platform; h the hopper; and i the anchor rope.

In another method the cane conveyances are tilted, electric or hydraulic
power being used, the canes falling into a pit similar to that in Fig. 97 ; this
system is illustrated in Fig. 99 (PLATE XV.). A view of a rake system of
unloading cane is seen in Fig. 100. The unloading appliance consists of an
endless chain passing over a frame which is hinged at its base, and is capable
of being raised and lowered. On the endless chain is arranged a series of angle
pieces, the whole system of chain and angle pieces forming a continuous rake.

167

CANE SUGAE.

When a car is to be unloaded the frame is made to descend on to the load of
cane, and the revolution of the endless chain causes the rakes to drag forward
the cane on to the carrier. The cars are sometimes built with a drop side,
which being let down forms a platform continuous with the carrier, but this
is unnecessary as if the tramway is laid close enough to the carrier the canes
fall directly on to the latter, which is of course arranged below the level
of the ground.

Another system shown in Fig. 101 (PLATE XV.) uses in place of the rakes
a single row of curved prongs ; to the pivoted beam on which these prongs are
fixed a simple to and fro motion is given ; the beam is also capable of
being raised and lowered ; this arrangement is independent of the dimensions
of the car so long as the latter is not so large as to be without the radius of
the beam's action, whereas with the system of the endless chain the dimensions
of the car and of the chain have to be correlated.

These cane unloaders are amongst the most efficient labour-saving devices
that have ever been introduced into the sugar industry ; the capacity of an
Asiatic in throwing canes is rather under one ton per hour and these machines
with but one attendant will discharge up to 50 tons in the same time.

Loss in Weight of and Deterioration in Cut Cane.— In

the modern system of central factories which receives canes from several out-
lying stations, the question of the loss in weight of canes between cutting and
milling is very serious, and very different results will be obtained in the
factory dependent on what is considered the weight of cane — the weight at
the outlying balance or the weight in the factory yard. As an example, let
there be 100 tons of cane as weighed at an outlying station, containing 12 per
cent, fibre, and let these canes lose by evaporation 2 per cent, before milling ;
the percentage of fibre will now be, calculated on a weight of 98 tons,
12-24 per cent., and these canes will give if crushed to a fibre content of
42 per cent., 70*91 per cent of juice, or 68-49 tons from the 98 tons received at
the factory ; the 'crushing ' is then either 70-91 or 68-49 according to which
weight is used; the canes if crushed fresh would have given 71*43 tons of
juice.

The average loss per day in fresh cut canes, exposed in heaps of about
50 Ibs., is from experiments made by the writer : —

Percentage loss in weight

Mean

168

4 hrs.

48 hrs.

72 lirs.

96 hrs.

120 hrs.

2-73 .

. 5-00 .

. 6-37 .

. 8-81 .

. 9-11

2-53 .

. 4-49 .

. 5-45 .

. 8-01 .

. 9-01

3-03 .

. 3'5() .

. 5-19 .

. 7-88 .

. 8-80

1-59 .

. 3-62 .

. 4-63 .

. 6-26 .

. 7-64

1-87 .

. 4-48 .

. 5-49 .

. 6-64 .

. 8-02

2-26 .

. 4-05 .

6-11 .

. 7-90 .

. 8-50

1-41 .

. 3-05 .

. 5-20 .

. 6-09 .

. 8-52

2-19

4'03

5-49

7-37

8-57

PLATE XII

FIG. 90.

FIG. 91

FIG. 92.

PLATE XIII.

THE HARVESTING OF THE CANE.

"Weinberg3 gives the following data showing the loss of available sugar in
cut cane : —

Days cut

0.

1.

2-

3.

4.

100 .

. 97-3

. . 92-0 .

. 78-6

. 67-9

o-o .

. 2-7

8-0 .

. 21-4

. . 32-1

o-o

2-7

5-3

13-4

10-7

Total loss of A. S

Daily loss of A.S. . . *J.

It has been shown in Java that cut cane when moist deteriorates much
less slowly than when dry ; deterioration is due to the death of the cells
which remain alive for long periods when wet. The writer has been informed
that in Java, (when, owing to breakdowns in the mill, it is necessary to let
large quantities of cut cane stand over) it is usual to cover the cane with
trash and to keep it wet by continually deluging the trash with water.

Browne4 has shown that the sugar in cut cane inverts more rapidly when
the immature top is left on ; the inversion takes place under the influence of
an enzyme which is present in greatest proportion in the top, and after the
cane is cut this enzyme diffuses into the juice of the stem.

KEFEKENCES IN CHAPTEE X.

1. Jour. d'Agric. Trop., 1906-35.

2. 8. C.t 205.

3. I. 8. «/., 59.

4. Louisiana Bulletin, 91.

169

CHAPTER XI.

THE EXTRACTION OF JUICE BY MILLS.

Mills, as row constructed for the extraction of the juice of the cane,
consist of heavy iron or steel horizontal rollers, driven by a steam engine
through powerful spur and pinion gearing. The rollers are set with their
centres at the angles of an isosceles triangle, the verticle angle of which is
generally about 83° ; but, sometimes, mills are met with having a vertical angle
considerably greater, even reaching up to 90°. The rollers draw the cane within
their grip, subjecting it in its passage to great pressures and causing the
rupture of the cells and the expression of the juice ; the latter falls on to the
bed-plate of the mill, whence it flows into a well and is pumped up to the
clarifiers for further treatment.

In almost all recently erected factories, the milling plant consists of not
less than nine rollers combined in three mills, the whole combination being
driven by one engine. In several instances, notably in the Hawaiian Islands,
twelve-roller combinations have been installed; in one case each in the
Hawaiian Islands and in Porto Rico, 15-roller combinations are employed, or,
including the crusher, 1 7 rollers. This last scheme, which is at work at the
well known Ewa and Guanica plantations, is a 15-roller mill in operation but
not in construction. At first the Ewa plant consisted of two nine-roller mills
placed side by side ; as afterwards arranged the canes pass through one of the
original sets, and are then transferred by a cross carrier to the second mill of
the other set ; in case of stress the oiiginal method can be used. This scheme is
the result of empiricism in regard to the capacity of mills. A number of years
ago it was thought that a mill 34 in. X 78 in. was run at its maximum capacity
when about 35 tons of cane were ground per hour ; but provided the mills had
enough engine power, it was found that much larger quantities could be worked
without detriment to the efficiency, and hence came the idea of utilizing the
existing train of mills to the best advantage, since the extraction, as is shown
later, increases with the number of crushings, the quantity of water added
remaining the same.

In twelve-roller combinations that have been formed by the addition of a
three-roller to existing plant the last mill is usually provided with its own
engine ; in others that have been laid down to one design a separate engine is
provided for each six-roller unit, the earlier one driving also the crusher or
shredder. In older plants, especially in those which have been built up

170

THE EXTRACTION OF JUICE BY MILLS.

piecemeal, each mill is driven by its own engine ; the advantage of the single
motor type lies in the synchronized working of each unit and in economy in
steam and supplies and labour.

The Three-Roller Mill.— The first mill with three rollers with
the centres arranged at the angles of an isosceles triangle was made in 1794
by Collinge ; in its modern form the headstock or housings on which the
rollers are supported may be considered as derived from a rectangle of rather
less height than breadth, gaps or openings for the insertion of the gudgeons
of the rollers being arranged symmetrically on the top and sides of the
rectangle. In Fig. 102 is shown in outline in half elevation the evolution of
the conventional form of headstock ; a represents a solid or rigid headstock of
massive construction and characterized by an exceedingly flat vertical angle.
The difficulty of removing a roller led to the insertion of a distance piece in
the shoulder of the headstock, the horizontal strain being taken up by a bolt

passing therethrough, as shown at b ; the modern form of headstock is seen
at c, where the set screws controlling the horizontal outward movement of
the bottom rollers are replaced by caps bearing directly on the brasses on
which rest the roller gudgeons ; the caps are held in place by heavy T headed
bolts recessed into the headstock.

In all these patterns tensile strains occur in the headstock which is
constructed of material unsuited therefor. The radical improvement is due
to Rousselot, a French engineer, of Martinique, who, while retaining the
form shown at c, passed the side cap bolts through the headstock whereby
the horizontal strains are taken up by the bolts which are constructed of
material adapted for that purpose.

In the original Rousselot mill four side cap bolts were employed ; these
passed without the vertical bolts ; indifferently four vertical bolts may be used
between which pass the horizontal or Rousselot bolts; another modification

171

CANE SUGAR.

consists of slotting either the vertical or horizontal bolts so that the whole
system lies in one plane. In the Delbert design, Fig. 105, but one horizontal
bolt is used, and it is entirely absent in the Krajewski-Pesant design shown
in Fig. 107.

In Figs. 103 and 104 are given side and end elevations of a modern
Rousselot mill; the principal parts are the headstocks or mill cheeks, the
rollers, the caps or keeps, the sole plate or bed plate, and the trash or dumb
turner. The headstocks b are heavy solid castings ; in them are three
openings — one at the top and one at each side, which serve for the intro-

103.

duction of the rollers a. The rollers consist of a shell of iron or steel,
which is forced by hydraulic pressure on to the shaft or gudgeon ; formerly
the shell was hung on the shaft by six or eight keys, and occasionally in old
mills square shafts are to be met with. The shaft, which is also called the
gudgeon, is constructed either of hammered scrap-iron, wrought-iron, or in
the most recent designs, of fluid compressed steel. The shafts are nearly
always made solid, as no benefit is obtained by a light, hollow shaft, and
it is desirable to keep their diameter as small as possible, consonant with
sufficient strength. The shafts rest on brasses h of gun metal of large

172

THE EXTRACTION OF JUICE BY MILLS.

bearing surface ; to one end of the shafts are keyed pinions gearing into each
other, by means of which motion is transmitted from the top shaft to the
two lower rollers. Generally mills are geared on one side only, but
occasionally gearing is found on both sides. The rollers are kept in position
by the caps d ; through these caps pass throughway bolts, which keep the
caps pressing on the bushes. The position of the rollers is adjusted by means
of these bolts. The headstocks rest on the sole plate g, to which they are
securely bolted ; all the vertical bolts pass through the foundation, and act
as holding down bolts ; the partially crushed cane coming from the top and

jfi

H

FIG. 104.

front rollers is directed to the top and back rollers by the trash turner, which
consists of two parts, the trash bar / and the trash plate, the curve of
which is also shown.

Solid Headstock Type. — The older type of three-roller mill is
seen in Fig. 105, and is referred to as closed headstock or rigid pattern ; the
side rollers are kept in place by set screws, passing horizontally through the
headstock. Mills of this type are still occasionally built, and so far as
' crushing ' is concerned, perform as well as the more elastic open headstock

173

CANE SUGAR.

pattern. They are, however, inconvenient to handle in the event of removing
a roller, and from their rigidity are more liable to fracture in case of any
unforeseen strain.

Stillmaii Mill. — In this pattern the vertical bolts are replaced by
a U bolt recessed into the mill cheek ; in other respects the conventional or
standard pattern is followed.

Allan Mill. — In this pattern the trash turner is absent entirely ; this
mill may be described as an ordinary three-roller mill turned through an
angle and with the original top roller reduced in size ; the two side rollers

FIG. 105.

then come nearly in the same vertical line with the centre of the original top
roller and approximately in the same horizontal line as the line of contact
of the other two rollers ; the small roller is then able to act as a feeding
roller to both the large rollers.

Inclined Bolt Type. — In some mills recently built by the Fulton
Iron Works the holding down bolts are bent and converge from a line below
the top roller journal to a point on a level with the seat of the lower roller
journal after which they again become vertical and pass through the bed

174

THE EXTRACTION OF JUICE BY MILLS.

plate. The original inclined throughway bolt mill was, the writer believes,
built by Fawcett, Preston & Co., under one of Chapman's patents.

External Bolt Type.— Mills are exceptionally found with the
vertical bolts passing without the shafts of the lower rollers, the top cap being
extended so as to receive them.

Delbert Mill.— This mill, shown in Fig. 106, has a triangular head-
stock, the usual vertical holding down bolts being replaced by bolts inclined
to each other at 60°, which do not pass through the bed-plate; these bolts lie
parallel with the lines joining the centres of the top roller and a lower
roller and hence in the direction of the principal strains; the hydraulic is
applied on the top cap and a very narrow trash bar is obtained.

© Cj) ----jfiSS******^

FIG. 106.

Krajewski-Pesant Mill. — A radical departure from conventionalism
is shown in the headstock adopted by the Krajewski-Pesant Co. in the H-type
of mill illustrated in Fig. 107. The headstock is of triangular form ; the
hydraulic pressure is applied to the back roller and in a line at right angles to
the layer of megass ; in this way the whole amount of the pressure is
exerted upon the megass ; the back roller may be said to float upon the ram
of the hydraulic, the movements of which it will follow with a minimum lag due
to reduced friction between the brass and the surface upon which it rests ; in tho
conventional mill the brass rests on a horizontal surface. Both front and back

175

CANE SUGAR.

rollers rest on surfaces at right angles to the direction of pressure, so that the
resolved force tending to push the rollers outwards is zero, and the necessity
for horizontal bolts disappears. The vertical throughway bolts are inclined
towards each other from above downwards giving a very narrow trash turner.

Hall's Inclined Headstock Mill.— A mill of the design
shown in Fig. 107a, was put in operation at the Pimnene factory of the
Hawaiian Commercial and Sugar Company in 1 909 ; the principle involved in

FIG. 107.

this design is the placing of the king bolts and of the hydraulic pressure in the
same line as the resultant of the stresses caused by the pressure between the
top roll and the front and back rolls. If the stresses between the top roll
and front roll, and top roll and back roll, were equal, tbe top roll would
tend to lift vertically ; owing however to the greater stress between the top
roll and back roll, there is a tendency to push the top roll upwards in a

176

PLATE XIV.

FIG. 97.

PLATE XV.

FIG. 99.

FIG. 101

THE EXTRACTION OF JUICE BY MILLS.

direction inclined towards the front roller ; in this design the hydraulic
pressure acts in a line nearly continuous with that joining the centres of
the top and back roller, and hence exerts a greater effective pressure on the
layer of megass than when it is applied vertically.

Fogarty Mill2.— This mill, shown in Fig. 108, completely departs
from conventionalism, the standard type of headstock being replaced by an
all steel circular housing

FIG. 107A.

The TWO -Roller Mill.— Two-roller mills, Fig. 109, have had
many advocates, who held that the strains would be more evenly distributed,
and that the power lost through the trash turner would be saved. In addition,
the rollers being in the same vertical line, it was argued, perfectly correctly,
that the whole of the pressure keeping down the top roll would be exerted in
crushing the cane; experience has shown, however, that they are not

177

12

CANE SUGAR.

successful, one very potent objection being that the rollers cannot be set close,
else the mill refuses its feed ; whilst in a three-roller mill, the front roller acts
as feeding roller to the back one. Two-roller mills were advocated by
Eousselot in Martinique, and by Alexander Young in the Hawaiian Islands,
as ' macerating ' mills to be used after a three-roller mill.

Four-Roller Mills. — Of four-roller mills, which have never come
into general use, the best known are the De Mornay and Le Blanc. The

m

FIG. 108.

former, which has been erected to some extent chiefly in Peru, Argentina,
and Brazil, is shown in Fig. 110. It consists of two main rollers a and 5,
and two supplementary rollers c and d. The cane is crushed three times,
between a and c, a and d, and a and b ; no trash turner is required. This mill
has given good results with long jointed canes, but with short jointed hard
brittle canes it has not been successful.

178

THE EXTRACTION OF JUICE BY MILLS.

The Le Blanc mill is shown in Fig. 111. It consists of a main central
roller 0, round the periphery of which are placed three other rollers 5, c, d ;
the cane passes between each of these and the main central roller, so that it is
crushed three times. Two trash turners e are required.

Five-Roller Mills.— The five-roller mill, which is frequently
mentioned in the ephemeral literature of the cane, is merely a typical three-
roller mill in which the headstocks are extended so as to receive a pair of
rollers which are placed above and in front of the three-roller mill ; the shaft

FIG. 109.

of the top roller of the mill proper is extended on one side so as to receive a
large spur wheel, which gears with one of equal diameter on the gudgeon of
the top of the two preliminary rollers. On the other side of these rollers are
pinions gearing with each other, by means of which motion is transmitted to-
the lower of the two rollers.

Nine, Twelve, and Fifteen -Roller Mills.— These terms merely
refer to the number of rollers in a train and not to the number of rollers in a
unit. The addition of a unit to an existing train has a two-fold effect, namely,
in increasing both the extraction and the tonnage worked. The writer's-
experience of these combinations may be thus summed up.

179

CANE SUGAR.

A nine-roller mill and crusher of size 30 in. X 60 in. will treat 20 tons of
cane per hour, and with mixed juice equal in weight to cane will give an
extraction of 93'5, the canes containing 12 per cent, of fibre ; a mill 34 in. x
78 in. will give the same results with 35 tons of cane per hour.

A twelve-roller train 30 in. X 60 in. under equal conditions will give an
extraction of 95*0.

A fifteen-roller train 30 in. X 60 in. under equal conditions will give an
extraction of 96-0.

A twelve-roller train and crusher 34 in. X 78 in. will treat up to 50 tons
of cane per hour and give an extraction of 94 -5 under the same conditions as
before.

FIG. 110.

A fifteen- roller train and crusher 34 in. x 78 in. will treat up to 60 tons
of cane per hour and give an extraction of 95-5 under the same conditions as
before.

The Motive Power of Mills. — With the exception of a few
instances in unprogressive districts, steam is the agent used to drive sugar
mills; wind power is still employed to some extent in Barbados, and where
water power is available no objection can be made to its use. Electrically-
driven mills still belong to the future, but the design of one prime motor, to
drive electrically all the machinery in a factory, offers no great difficulty; and,
where water power is available, the design of a system of turbines, dynamos,
and motors to drive all the engines and pumps in a factory without burning any
fuel for motive power, is quite feasible, and milling plants have been erected
where the motive power is derived from a fall of water through a Pelton wheel.

180

THE EXTRACTION OF JUICE BY MILLS.

The engines used to drive sugar mills are either beam engines or horizontal
engines; generally, owing to the type of labour available, the design of the
engines is as simple as possible. Whether beam or horizontal, they are nearly
always simple non-condensing engines, the exhaust steam being used in evapora-
tion. Beam engines make a handsome ornament to a factory, but they are more
expensive in first cost ; their cylinders, however, do not require re-boring. The
horizontal engines used are nearly always single cylinder engines ; occasionally,
when the engine is at a dead centre, the cane mill chokes, and it may be necessary
to lever the fly-wheel round to allow the engine to re-start. A two- cylinder
engine, with cranks set at right angles, would overcome this difficulty, and the
writer has seen such an installation at work in a modern mill ; but in all the
recently erected mills in the Hawaiian Islands single cylinder non-condensing
engines of the Corliss type have been erected.

FIG. ill.

The Gearing of Mills. — The intermediate gearing which transmits
power from the engine to the mill consists of heavy toothed wheels ; occasionally
helical teeth are employed. Except in small mills the spur wheels are built up
in segments ; usually there are from six to eight arms, to which are bolted the
segments of the gearing ; the pinions are cast in one piece, and are usually half
shrouded. In Figs. 112 and 113 are shown two methods of connecting up the
gearing of a single motor nine-roller mill; a is the fly-wheel, JL the first motion
pinion, cl the first motion spur wheel, b2 and c2 the second motion pinion and
spur wheel. In Figs. 112 and 113, bt transmits motion to both spur wheels,

181

CANE SUGAR.

whiclf in turn convey power to the spur wheel c2 by the pinion 12. The ratio
of gearing is 20 : 1, and with an engine revolution of 40 per minute gives a
peripheral speed to the rollers 30 inches in diameter of 15-7 feet per minute.
In the plan as arranged in Fig. 112, a much more compact train of gearing
results, and this is the form usually adopted in modern plants. As a modifica-
tion, the first motion gearing can equally well he connected to the pinion
between the first and second mills, and in the scheme in Fig. 113 the greater
distance between the two mills may be between second and third or first and
second, dependent on whether the mill at extreme right or left is considered to
be the first mill; in either case the distance between the two mills closer
together can be increased by increasing the size of the spur wheel without
altering the speed of the mill.

FIG. 112.

The purpose of the arrangement in Fig. 113 is to obtain a means of
•complete maceration in baths between the mills, an object which cannot be
attained by the more compact system illustrated in Fig. 112. This question
is discussed at greater length further on.

It is now the rule, in single motor driven plants, to so arrange the gearing
that there is an increase in speed from mill to mill ; in the Hawaiian Islands
it is customary to find peripheral speeds in the mill rollers of about 20, 23,
and 26 ft. per minute in the first, second, and third mills respectively ;
formerly much lower peripheral speeds were customary.

The Trash Turner. — The object of this appliance is to direct
and guide the partially crushed cane between the top and back rollers ; it
was invented by a Barbados planter called Bell, the operation having
previously been performed by negroes. The trash turner consists of two
parts, the trash bar and the trash plate ; the trash bar consists of a massive
iron or steel casting ; it may be of rectangular, pear or of I section ; in older
mills it is often found supported on openings in the headstoeks, as in Fig. 102.
In more recent patterns it is carried on chairs cast on the inner side of the

182

THE EXTRACTION OF JUICE BY MILLS.

headstocks ; these chairs may be a plane surface in which case the adjustment
of the trash turner is effected by the insertion or removal of wedges. In yet
more recent designs the trash bar is mounted on a trunnion bearing as seen at I
in Fig. 108 ; its adjustment being made by means of the lever as a bearing
on the mill cheek.

FIG. 113.

The size and setting of the trash turner is a point of very considerable
importance. In the first place its object is to direct the partially crushed
cane between the top and back rollers, and it is usually set sloping slightly
downwards in the direction in which the cane travels. If it is set too close
to the rollers, there is insufficient room for the blanket of megass to pass
without causing enormous friction, and if set with too great a clearance it
ceases to perform its proper functions. As friction depends on the area of

183

CANE SUGAR.

contact, its width should be as small as possible. The width of the trash
turner is determined by what may be called the vertical angle of the mill, i.e.,
the apex of the triangle formed by joining the centre of the rollers; the
larger this angle, the wider the trash turner. In actual practice, vertical
angles lying between 75° and 90° are met with, a very general angle being
about 82°- 84°. In addition to a small vertical angle diminishing the width
of the trash turner, the component of the downward pressure exerted
vertically on the top roller, on the line joining the centres of two rollers, is
greater. There is a limit, however, to decrease in the vertical angle since, as
this narrows, the space available for the shaft of the lower rollers becomes
less. By the employment of the best material, mills with small shafts of
sufficient strength and narrow trash turners can be made.

A very large number of curves has been suggested for the trash turner,
in all of which the personal equation of their originators appears very largely.
On certain mathematical grounds it can be shown that the correct curve is a
logarithmic spiral, the construction to obtain which is given below. The
method which appeals most to the writer is one of trial and error : — indicating
the engine with different settings, and adopting that setting which is
found to absorb least power. Another essentially practical method is to adopt
that curve into which an old trash plate has been worn. It must be borne in
mind, however, that the proper curve and setting is dependent amongst other
things on the nature of the canes ground, particularly on the amount of fibre
and on its mechanical structure and resistance to compression, so that a
setting satisfactory with one lot of canes may be the reverse with another ;
continual watchfulness on the part of the engineer is called for here.

The efforts of engineers have been directed largely in late years towards
diminishing the width of the trash turner, and towards obtaining at the same
time a small apex to the mill ; all the departures from conventionality
instanced above have had this point in view.

Bergmans' Theory of the Trash Turner3.— The following
mathematical treatment of the trash turner was published in 1889, by
R. F. Bergmans and is here reproduced : —

The duty of the trash turner in sugar mills is to direct the crushed cane
from the first cylinder pair (one and two) to the second (two and three).
The crushed cane must be so guided that cylinder 3 can take the feed
without stopping the working of the plant.

Let T! represent the speed with which the crushed cane leaves the
first cylinder pair and T2 that of the bagasse leaving the second cylinder pair
(see Ftg. 114) > then must always 7\ = T2 and it hence follows that the
passage of the bagasse over the trash turner must be uniform.

184

THE EXTRACTION OF JUICE BY MILLS.

Consider the movement of a pointy (Fij. 115} • using a system of polar
co-ordinates the point p will reach A in time t with a velocity V\ this
velocity can be divided into two components c and w, of which c is in the
direction of the radius vector and w is perpendicular to it. The crushed cane
must move over the trash turner in such a way that these components are
constant, a result to be obtained by the following conditions : —

FIG. 114.

If r and u are the polar co-ordinates of the point p, then

dr
C = -j7 or dr = c dt,

now, since C i3 constant, one obtains by integration

r — ct + <?!.

The value of Cl is obtained by considering that when t — o, r must be equal
to R. Using these equalities it follows that

Further

Cl = R
r = ct + R

r .du

w =

(1)

dt
or w.dt = r.du.

The value of r can be obtained by substitution from (I) whence it follows that

w.dt — (ct + R) du
or w . dt

ct + R

= du.

On integration

w

u = - log (R + ct) -f C2.

The constant C2 can be obtained by putting t — o and u = o, whence

C, = - log R.
185

CANE SUGAR.

Substituting this value of C2 it follows that

u = — log (R -\- ct) log R

or u = ~ log R + et (2)

Whence from (1) and (2) it follows that

10 r .

r c
or log R = w u

If, for simplicity, m be written for — , and if R be put equal to (1), this

equation reduces to log r = m.u

or r = e"'» (3)

The equation (3) is none other than that of the logarithmic spiral where
e is the base of the natural system.

This curve has the property that the radius vector always makes with
the tangent a constant angle; thus the angle a is constant. Now (see Fig. 116),

c

m = — =. tan a
w y

and g = 90° - a

then m = cot a =. constant.

Draw ON perpendicular to OA, and .4 A7" perpendicular to T.
Then ON = r cot a = rm.

T

In addition NA — r r~i — i ?-— — • • Equation (3) gives the path

\/ 1 -|~ m2 sin a \ / o

which the point p describes as a logarithmic spiral ; for sugar mills this curve
is of definite length.

186

THE EXTRACTION OF JUICE BY MILLS.

The path, then, which the point p and also the crushed cane describes is
a part of a logarithmic spiral ; in order to obtain this path for sugar mills the
velocities w and c must be known. The velocity w, which is perpendicular to
the radius vector, is always equal to T, the velocity with which the bagasse
leaves the first cylinder pair. The velocity c is to be determined experi-
mentally, and depends on the elasticity of the crushed cane, and that the
cylinder 3 must easily carry forward the bagasse. Before determining
empirically the values of c and of the angle a, we will look first at the
following considerations : —

In Fig. Ill, 8 is the opening between the cylinders 1 and 2, and d is the
thickness of the crushed cane, and when the cane is not elastic d is equal to 8 :
in this case the velocity C can be put equal to 0 for there exists absolutely no

FIG. 117.

reason why the crushed cane should proceed with a velocity C lying in the
direction of the radius vector in order that it should easily and without
excessive friction pass over the trash turner. When c = 0, m also = 0, and
a — 90. It then follows

r = c = 1 = R or r = R = constant.

In this case the trash turner is a circle of radius r = R •=.— + «, where D is
the diameter of the roller cylinder.

In practice such a condition never occurs, due to the pressure between the
top cylinder and the trash turner following on the elasticity of the crushed
cane.

This is why C must always be greater than 1 . If C becomes too great,
then the cylinder 3 cannot take the feed and will cause a stoppage. The
velocity C must be such that the angle A is somewhat less than 90°.

The trash turner curve following this argument of Bergmans can be found
graphically with close approximation as follows : —

187

CANE SUGAR.

Draw the positions of the rollers to scale, Fig. 118 ; join OB and OC\
draw XT parallel to OC; draw JO7" perpendicular to XT, cutting 00 at N-,
with JVas centre and NK as radius draw an arc JOf ; then -Of is very close
to the original logarithmic spiral.

J. N. S. Williams4 gives the following data regarding a nine-roller mill
at Puunene, in the Hawaiian Islands : —

Pressure on top roller, tons

Distance of trash plate from top roller . .

Opening of top and front rollers . .

Opening of top and back rollers . .

Distance between trash plate and 1:

Speed of rollers, feet per minute . .

Engine : — 60 in. X 30 in. Working pressure at boilers 83 Ib. per square
inch. Average horse-power developed, 317*86. Revolutions per minute, 48.
Tons of cane per hour, 50 '28 short tons.

First Mill.

Second Mill.

Third Mill.

230

320

400

D roller . .

2 in.

. . 1-5 in. .

. 1-25 in.

:s

1-125 in.

. . -625 in. . ,

. -3125 in.

•s

•4375 in.

. . '25 in. .

. -0625 in.

nd back roll .,

, 1-25 in.

1 in. .

•75 in.

te..

20

23

26

FIG. 118.

In Java, a distance between trash turner and top roller, measured along
the vertical line through the centre of the latter of about 55 mm. (2-45
inches) for mills 30 in. X 60 in. (crushing about 600 tons in 24 hours) has
been found very satisfactory; for every 1000 piculs (60 tons) increase in cane
milled per 24 hours, the distance between trash turner and top roller is
increased 3mm. (•$• inch) or so.

Proportions of Mill Rollers. — A very general proportion for the
size of rollers is that the length be twice the diameter. Increasing the
diameter of the roller calls for greater power to drive, and at the same time
increases the tendency to fracture, due to torsional strains ; at the same time
the gudgeons can be made larger, and whereas the torsional strain only
increases directly with the diameter, the strength of the gudgeon increases
proportionately to the square of the diameter. Another objection to rollers of
large diameter is that the trash turner also becomes larger, and the friction

188

THE EXTRACTION OF JUICE BY MILLS.

FIG. 119.

189

CANE SUGAR.

is here materially increased ; on the other hand the curve of large rollers being
flatter, cane is a longer time in contact and under pressure, and the rollers
being further apart there is less risk of re-absorption, but at the same time,
owing to the flatter curve, juice flows from the rollers less easily. A very
favourite size in recently erected plants is a roller 78 in. X 36 in., experience
having apparently shown that increase in diameter above this size is not
attended by better results. When not increasing the diameter in proportion
to length, the diameter of the gudgeons, and consequently their strength,
does not increase in proportion to horse-power transmitted. A roller of such
dimensions must essentially have its shaft made of the very best material ;
such a proportion with inferior material would only result in inferior work or
in breakages.

Preparation of Cane for Milling.— In the great majority of
modern mills the canes are subjected to a preparatory treatment before they
enter the mill proper ; the increased use of these appliances has been the
outcome of various causes. In the first place it has been found that, by a
preparatory treatment, the capacity of a milling plant is greatly increased,
without any detriment to the quality of the work. Secondly, the use of
unloading machines gives a mass of material much more uneven than that
obtained by hand loading, so that the mill will often refuse the feed. The
devices used in the preparatory treatment of the cane do not so much extract
juice as that they level the mass of cane, and prepare it for the milling process
proper. Thirdly, the replacement of the older varieties of cane by others,
notably by certain seedlings, has resulted in the handling of a brittle
material, which in many cases almost refuses to pass between the rollers of
an ordinary mill without previous partial treatment.

The appliances used may be classed under three heads, crushers,
shredders, and revolving knives. Of the first, the Krajewski crusher,
Figs. 119 and 120, has been largely erected ; it consists of two superimposed
rollers ; each roller is grooved at equal distance over its surface in such a
way that the grooves form a succession of V shaped teeth, the teeth in one
roller being opposite the recesses in the other. The rollers in this appliance
can be placed at varying distances, so as either to crush the cane or even cut it
into pieces of about four inches in length. The crusher is made to be worked
off its own motor, or it may be driven ofi° the main mill gearing. With
mill rollers of 34 in. in diameter, it is customary to have the crusher
rollers of about 26 in. in diameter, and to run them at a higher speed than the
mill rollers, a peripheral speed in the crusher rollers of 28 to 30 ft. per minute
being usual.

190

THE EXTRACTION OF JUICE BY MILLS.

FIG. 120.

191

CANE SUGAR.

Cane shredders consist of two cylinders, on the surfaces of which are
shrunk V shaped rings, as shown in Fig. 121 ; these cylinders are run at a
high speed, the upper one making usually 250 revolutions per minute ; the
lower cylinder is geared to make twice as many revolutions as the upper one.

FIG. 121.

On passing between these cylinders the cane is subjected to torsion, and is so
to speak 'shredded,' but no juice is extracted, the treatment being entirely
preparatory.

FIG. 122.

The general form of cane cutter is seen in Fig. 122 ; it consists of a
cylinder on the periphery of which is arranged along a helix of slight slope
a number of curved knives ; these knives are spaced about 4 in. apart and are
.about 12 in. long; the cutter, which is run at about 300 revolutions per

192

THE EXTRACTION OF JUICE BY MILLS.

minute, may be driven by its own motor, or very conveniently by belt gearing
off the mill engine. The useful effect of this contrivance is very pronounced,
and provided the knives are kept sharp but little power is used.

In some recent patterns the preparer is incorporated in the mill itself,
and takes the form of a heavily indented top roller; three designs on the
market are known as the Diamond, Excelsior, and Pelaez rollers ; in the first-
mentioned the surface of the roller consists of a number of prisms arranged
at right angles to each other, so that the surface comprises a large number of
L shaped units.

Of the earlier cane preparers, reference may be made to that of Faure,
similar in principle to the shredder but with the bottom roll replaced by a
fixed counter plate ; to that of Bonnefin, consisting of a system of reciprocating
saws, and to that of Mignon and Rouart in which the cane was fed into a
cylinder wherein revolved a system of knives. This last device was based on
the machines designed to pulp straw for paper making.

FIG. 123.

Forced Feed. — A diagram illustrative of the ' pusher ' or forced feed
is shown in Fig. 123; it is an apparatus designed automatically to force
megass into a second or third mill and at the same time to ensure an even and
regular feed. It consists essentially of a strong iron bar extending the length
of the roller to which a to-and-fro motion is given by means of a spur and
pinion and lever gear worked off the gearing of the cane engine ; the rocking
bar moves below the feeding table and above the front lower roller, and forces
the megass into the mill by impact. In Fig. 123 a represents a spur wheel
6 ft. in diameter worked off the shaft of the second motion pinion of the cane
engine ; this wheel gears with a pinion b 1 0 in. in diameter ; the pinion carries
on one side a flange c, 20 in. in diameter ; attached to the flange by means of
a pin is a strong bar d which works the piece e to which is communicated a
backwards and forwards movement in an arc of a circle ; to e is attached a bar
/ running parallel to the rollers ; / carries, placed at either end of the roller,
pieces similar to e and to these is attached the pusher which forces the megass
to the rollers. The pinion makes about 70 revolutions per minute, and this is
consequently the number of strokes given by the pusher.

193

13

CANE SUGAR.

Pressure Regulators. — Mills of the pattern exemplified in Fig*
101 may be referred to as rigid mills, that is to say, the distance the rollers
can be separated is limited by the setting and depends on the elasticity or
' give ' of the mill ; with such a pattern the pressure exerted on the layer of
megass is dependent on the quantity passing and any sudden strain, due either

to malice or accident, may result in the fracture of the mill. To overcome
this trouble all recent mills are provided with pressure regulating devices
which both maintain a constant pressure down to a certain minimum thinness
of feed and also allow a roller to lift in the case of the passage of any in-
compressible material such as of a piece of iron.

194

THE EXTRACTION OF JUICE BY MILLS.

Patents for the hydraulic regulation of mills were granted to Stewart in
England in 1871, and to MacDonald in the United States in 1872.

In Fig. 12 If is given a view of an hydraulic applied to the back roll of a
mill and conforming to the arrangement generally followed by English
engineering firms. The hydraulic pressure is applied by means of the ram
g ; if in any way the pressure becomes greater than that exercised by the ram,
the latter gives way, allows the rollers to move and relieves the pressure.

FIG. 125.

The plant consists of a small hand pump a, by means of which a fluid,
generally oil, is pumped through the pipe e e into the upright hollow rod d,
Through d runs a channel about one quarter of an inch in diameter,
communicating by a small aperture with the cylinder b ; c c are weights which
rest on the flange k\ as the pressure in the oil increases it raises these weights,
and the pressure throughout the system is that due to the weights ; the pipe e
is continued through the cap /, the oil filling the hollow space enclosed
between the cap / and the ram g. By a well-known principle of hydraulics if
the area of the cross section of the ram is a and that of the fluid in the

195

CANE SUGAK.

accumulator is b the pressure required to move the ram is -y- where x is the
sum total of the weights c c. When this system was first brought out the
pressure applied was generally three tons per linear inch of roller, so that a
roller sixty inches long had a pressure on the journals of 180 tons; to obtain
this pressure the weights co would be about two tons, but now pressures of
four, five, and even six tons per linear inch are not unusual.

In MacDonald's design (and this is the form usually adopted by United
States engineering firms) the hydraulic is arranged beneath the mill, as shown
diagrammatically in Fig. 125. The pot of the hydraulic is seen at a bearing
directly on the sole plate of the mill ; the oil chamber is seen at c and the ram
at b ; the holding down bolts are united by a yoke seen at d. The action of
the two types is practically identical, a direct push in one case being replaced
by a pull.

FIG. 126.

In the MacDonald type of hydraulic the tension is transmitted through the
holding down bolts which may be as much as eight ft. long; any inaccuracy
there is then magnified in the adjustment of the top cap, and in addition the
unequal strains in the mill have a tendency to force the top cap out of the
plumb, so that it may jamb against the side of the mill and prevent the hydraulic
regulator acting ; on the other hand, the design is readily accessible, and burst
leathers can be replaced in a few minutes.

A source of trouble in all types of hydraulic is the unequal pressure on
either side of the mill due to the thrust of the pinions ; this may in part be
compensated by making the area of the rams of different size, but in this case
the allowance once made is fixed. A more elegant scheme entails the use of
twin accumulators which may be loaded independently, and an equal travel on
both sides of the mill obtained by trial and error.

The location of the hydraulic varies in practice ; it is found applied to the
top and to the back roll; in the former case it acts as a safety appliance
equally to the front roller, and this is the more rational method to follow, as is
also indicated by the following argument.

196

THE EXTRACTION OF JUICE BY MILLS.

In Fig 126 let a, 3, and c represent the centres of the rollers of a three-
roller mill ; let the angle lac be, as is very usual, 84° ; then the angles abc
and acb are each 48° ; let w represent a vertical pressure applied to the top
roll ; the line along which w acts will if produced bisect the vertical angle of
the mill, so that the angle cad is 42° ; the component of w along ac, that is
along the line joining the centres of the top and back roller, is W cos £2°, so
that if w is 300 tons, the pressure on the megass is 300 X 743 or 222-9 tons.
If now a horizontal pressure w1 be applied to the back roller, the component

FIG. 127.

along ac is w1 cos Ij.80 and if w1 be 300 tons, this quantity is 300x*669 or
200-7 tons; hence with mills of the usual pattern a greater effective pressure
is obtained when the hydraulic acts on the top roller.

The above argument shows too how with a small apex to the mill a greater
effective pressure along the line joining the centres of the top and a lower
roller is obtained ; neglecting the difference in opening between top and front
and top and back roller, this is given by w cos a2 where w is the vertical
pressure on the top roller and a is the apex or verticle angle of the mill.

197

CANE SUGAR.

The toggle gear, Fig. 127, introduced and patented by the Mirrlees Watson
Company, consists essentially of a combination of springs and knuckle or toggle
levers, the tops of which press against the nuts of the cover bolts and the
bottoms against the caps of the roller journals; under normal conditions the
rollers rest on their bearings, but under heavy pressures they lift the caps
which are controlled by the toggle gear until the upward pressure is balanced
It is claimed for this contrivance that it is less expensive than a hydraulic
regulator and that it performs the same duties ; as in the hydraulic, the pressure
can be regulated, in this case by adjusting the nuts that compress the springs.

Cane Carrier. — The apparatus used to transport cane from the cars
to the mill is usually an endless belt slat conveyer, on the inside of which is
arranged a link belt ; gearing with this link belt are sprocket wheels driven by
a chain drive from the mill ; the driving sprocket can be thrown in or out of
gear by a clutch ; latterly cane carriers have been made independently driven
by small engines.

Megass Carriers. — The intermediate carriers of the megass are
usually slat carriers which leave much to be desired; belt conveyers have
recently been used with much success in the Hawaiian Islands ; in place of
slat conveyers scraper carriers are sometimes seen, especially when the megass
has to be elevated at a steep angle to the furnace room.

Strainers. — The removal of fine particles of fibre from the juice is
best effected by arranging a long narrow tank parallel to the line of the mill
into which the juice discharges through a perforated copper strainer ; on this
strainer runs an endless rubber-faced scraper which sweeps off the 'cush cush'
and, after elevating it, discharges it into a screw conveyer running across the
first mill ; as this * cush cush ' contains much grit which injures the surface
of the rollers the idea of passing it through a very small mill has been put
into practice. Revolving strainers operated by the head of juice itself are
also in use.

Calculation of necessary Opening between Rollers.*—

In order that the fibre, and the juice that accompanies it, may be passed out
from between the rollers, it is necessary that there be a certain opening ; the
product of the opening into the area described by the revolution of the roller
by a horizontal line on the circumference of the roller, that is to say, by the
crushing surface, is a volume, which cannot be less than the combined volume
of the emergent juice and fibre. As an example of the point made above let
there be a mill with rollers 30 in. X 60 in. ; then in each revolution of the
roller the crushing surface is TT x 30 X 60 sq. in. If the opening between
the top and megass roller is ^V in-> then the volume described between the two
rollers in one revolution, and which cannot be less than the combined volume

* The sections immediately following apply primarily to rigid mills and are only applicable
to hydraulic mills in a limited sense.

198

THE EXTRACTION OF JUICE BY MILLS.

of the emergent juice and fibre, is7rx60x30x^ cubic inches. For
lack of a better term this volume will be referred to in the sections immediately
following as the escribed volume.

In the megass mills it is customary to set the top and back rollers
practically metal to metal, and hence to allow the megass to pass, the rollers
must become separated by a certain distance, which can be obtained by the
calculation given below.

Let there be a mill of dimensions 60 in. X 30 in. running at the rate of
two revolutions per minute; let 25 tons of cane carrying 12 per cent, of fibre
be crushed per hour; let the megass as it leaves the mill contain 45 per cent.
of fibre and 55 per cent, of juice; let the density of the juice be 1*07 and of
the fibre be 1-35. Then in one hour there pass 3 tons of fibre and 3'66 tons
of juice. The volume of the fibre passing per hour is

3 X 2240
62-25 x 1*35 = ^9'96 c* ft-» an(^ ^at °^ *ke Ju*ce *s

- 123-19 c. ft.; and together 203-15 c. ft.

To allow this quantity to pass, the escribed volume must not be less;
the crushing surface per revolution is — ~TTT — — sq. ft. = 39-28 sq. ft. ;

so that at a speed of two revolutions per minute the minimum opening

20S* 1 5
between the rollers is 39.28 x 120 ~ '°43 ft> = **in'

If the rollers ran at 2'5 revolutions per minute, the minimum opening
works out at ff in., so that with high speeds a smaller opening is necessary.

In actual practice the megass and top rollers are set metal to metal, and
not to such relatively large distances as the above calculation implies; the
volume necessary for the megass to pass is made up of the spaces formed by
the grooving of the rollers, by roughness in their surface, and also by actual
distortion and forcing apart of the rollers.

In the above conception it is necessary to distinguish between the actual
and the apparent volume of the megass ; the latter is the space occupied by
the megass and includes the intercellular and interstitial spaces, and depends
upon the structure and packing of the fibre ; the former is the least volume
into which the megass could be packed on the supposition that the space
is filled wholly with megass.

Capacity of Mills.— It is easy to see that, provided all other con-
ditions remain constant, the capacity of a mill is fixed by the escribed
volume, and hence if two mills of different size be run at the same peripheral
speed, that the capacity is fixed by the crushing surface. There are, however,
many factors that do not remain constant, and which can be varied at will, so
that so simple a relation does not hold. As a matter of empirical observation

199

CANE SUGAR.

the writer has noticed that the capacity of mills otherwise similar is
proportional to the cubic contents of one roller, and that, in the case of a
nine-roller mill and crusher, the following simple relation holds. The capacity
in short tons of cane per hour is equal to the cubic contents in feet of one roller.

Three sizes of rollers often found are 30 in. X 60 in., 32 in. x 66 in.,
34 in. X 78 in. ; the cubic contents of these rollers are 24*5 c. ft., 30*7 c. ft.,
and 41*4 c. ft., and these figures represent very closely the amount of cane
treated by mills of this size in combination with a cane preparer.

The addition of a fourth mill is found in practice to add at least 25 per
cent, to the capacity without detriment to the quality of the work, and the
absence of a cane preparer to take away about 10 per cent.

FIG. 128.

The capacity of an existing plant can be varied within certain limits
without detriment to the quality of the work by regulation of the escribed
volume; this can be controlled by increasing the peripheral speed of the rollers
or by increasing the opening between them ; if the capacity of a mill is to be
increased on these lines, it is of course necessary that there be sufficient
engine power available to treat the increased quantity of cane. The capacity
of a mill is also affected by otber causes that cannot well be treated on paper ;
some of these are : —

1 . The nature of the material treated, including such points as the hard-
ness, brittleness, and fibre content of the canes.

2. The ' slip ' of the mill.

3. The roughness of the rollers ; it is a matter of experience that the
capacity of a mill is increased with rough surfaces, and rollers are now made
with a special coarse-grained surface ; grooving the rollers has a similar
effect. Forms of grooves as found in practice are shown in Fig. 128.

5. The setting of the trash bar.

6. The regularity and evenness of the feed.

Surface Speed of Rollers as affecting Expression of
Juice. — A number of years ago 15 to 16 feet per minute was a usual surface

200

THE EXTRACTION OF JUICE BY MILLS.

speed for mill rollers. The more recent tendency is to design the gearing so
that the mills run at a speed up to 25 feet per minute. It has also been the
custom to so arrange the gearing that there is an increase in the surface speed
from mill to mill ; a thinner blanket of megass is thus obtained, which it is
claimed parts with its juice more readily than the thicker blanket obtained if
all the mills run at the same speed.

By a reversal of the calculation given in the preceding section, it follows
that, if the volume escribed by the revolution of the rollers is 203-15 cubic
feet, the megass consists of 79-96 cubic feet of fibre and 123*19 cubic feet of
juice ; let this volume of megass which is derived from 25 tons of cane be
passed with the rollers making 2-5 revolutions per minute ; let the speed be now
reduced to 2 revolutions per minute ; then the volume now escribed by the
rollers in one minute becomes, if the setting remains unaltered, 182-52 cubic
feet : since the volume occupied by the fibre is the same in both cases
(79-96 c. ft.), there is with the slower speed a volume of (182-52-79-96)
or 102-56 c. ft. remaining for the juice; taking this as of density 1*07 as
before, the composition of the megass now works out at 50*4 per cent, juice
and 49-6 per cent, fibre, as compared with 55 per cent, juice and 45 per cent,
fibre when the speed was 2 '5 revolutions per minute. In the opinion of the
writer, this argument points to the obtaining of better results with small
speeds ; the reasoning is not free from objection since, for example, with the
thicker blanket there will be a greater tendency to force the rollers apart and
thus to increase the escribed volume.

Quantity of Fibre in Cane as affecting Composition of
Megass. — The conception of the escribed volume can be used to show how
the percentage of water and of fibre in a megass will vary with the initial
composition of the cane. In the example already taken it was shown that,
with an escribed volume of 203-15 c. ft., canes containing 12 per cent, of fibre
afford a megass of composition fibre 45 per cent, and juice 55 per cent. ; let
canes containing 1 0 per cent, of fibre be now milled, the setting and speed of
the mills and the weight of cane remaining unchanged ; the amount of fibre
now passing in one hour is 2'5 tons and this quantity will occupy 66*63 c. ft.,
so that there remains 203-15— 66-63=136-52 c. ft. to be occupied by the juice ;
this volume of juice, if of density 1*07, will weigh 4*06 tons, and the total
weight of megass will be 6-56 tons, so that the percentages of fibre and juice
are 38-1 and 61 -9 respectively.

It follows then, that with a fall in the fibre content of the cane the escribed
volume must be decreased to obtain the same results as with the larger quantity
of fibre ; this effect can be obtained by running at a slower speed or by
decreasing the distance between the rollers ; conversely, megass of the same
composition will result by increasing the quantity of cane milled.

201

CANE SUGAR.

Saturation — By this expression is meant any process where water
is added to the dry crushed canes, which are then recrushed; a diluted juice
containing a proportion of the juice left after the dry crushing is then
obtained ; two methods of applying the water may be distinguished ; in one
the water is allowed to impinge directly on the megass, and in the other the
diluted juice is returned to a bath, through which the megass is drawn. In
Mauritius the writer observed that the term * imbilition ' was applied to the
former, and '•maceration'' to the latter process; in what follows these terms
are adopted.

The earliest mention of a saturation process is due to Wray ; he describes
a plant at work in Province Wellesley in 1848 ; it consisted of a three-roller
mill as the dry crusher, followed by a two-roller mill as the recrusher ; the
megass was carried from the first mill to the second by a travelling band, on
which fell a rain of hot water from an overhead tank ; the surplus water that
drained off was sent to the distillery.

In order to obtain a premium of 100,000 francs, Duchaissing introduced
a saturation process into the island of Guadeloupe ; the apparatus was very
similar to the one described by Wray ; the two mills were placed eighteen
feet apart, and between them ran a travelling band, the underside of which
dipped into a tank of hot water while another tank placed above
distributed a rain of hot water over the megass. Over the travelling band
was arranged a series of beaters. The juice from the two mills could be
collected separately, and if the second mill juice was greatly diluted it was
returned to the megass from the first mill.

Kussel and Eisien's scheme introduced into Demerara about the same
time was somewhat different ; the mills were placed about thirty feet apart
and connected as before by a travelling band. This band ran in a closed
chamber of the form of a shoot ; a system of perforated piping ran along the
bottom and top of the shoot by means of which water or steam was forced
upon the megass ; means were also here provided for treating the first and
second mill juice separately.

Eousselot, who also reduced the cane mill to its present form, patented
and introduced into Martinique a system of saturation; his process was
essentially one of imbibition. In the Hawaiian Islands saturation was intro-
duced by Alexander Young who sold mills on a system of payment by results.

All these schemes were incepted in the seventies.

Maceration. — In Fig. 129, is shown a train of two mills separated
by a macerating bath. Several ways of operating this process are to be met
with. With a train of three mills, imbibition may be practised between the
second and third mills and the third mill juice may be pumped into the bath
between the first and second mills ; in any case the returned juice enters the
bath at the end next a later mill and flows in a direction opposite to that in

202

THE EXTRACTION OF JUICE BY MILLS.

"T

203

CANE SUGAR.

which the megass travels, finally overflowing at the end next the earlier mill
whence it passes to the boiling house.

Macerating baths may also be arranged between the last two mills of a
train, say, of three mills ; in this arrangement the expressed juice from the
last mill is returned to the bath in front of the last mill ; the added water
enters the bath immediately behind the returned juice. The flow of the juice
is as described above, and on leaving the bath it is pumped to the bath
between the first and second mills, and on overflowing from this bath passes to
the boiling house, together with the juices expressed from the first and second
mills.

In another scheme, the juice expressed from the second mill is also
returned to the bath between the first and second mills along with the third
mill juice, and finally added water may be used in this bath as described
above, the juices from the second and third mills passing separately to the
boiling house.

The juice in the baths is removed before the mills stop, by ceasing to
return the juices for about 30 minutes before closing down ; the megass, in its
passage through the bath, then mops up the juice present at the time that the
return of juices is stopped.

Comparison of Imbibition and Maceration.— In all the

recently erected mills in the Hawaiian Islands an imbibition process is used;
the mills are placed close together, being driven through the train of gearing
shown in Fig. 112 by one engine. With this arrangement there is no
room for a macerating bath. The majority of plants recently erected in
other districts also conform to this pattern ; macerating baths are to be found
in Mauritius, in Fiji and in Australia, but the process is not by any means as
common as imbibition. The writer has always been an upholder of the
maceration process, and formed this opinion from the results obtained when
once in a position to make comparative tests. In view, however, of the balance
of opinion in favour of imbibition, he is unwilling to dogmatize on the subject.

The benefit of maceration is most pronounced with the imperfectly crushed
megass coming from an earlier mill : generally the rupture of the cane is at this
stage so imperfect that the water added as imbibition is but little absorbed.

To a certain extent the preference of engineers for a compact train of
gearing, and considerations of first cost, account for the more extended use of
imbibition ; where the mills have each their own engine, as is the case in plants
erected piecemeal, this objection to maceration does not hold.

General Principles in Saturation. — In conducting saturation
processes the following points are of importance : —

1. The water must be evenly distributed over the megass.

2. The water must penetrate into the megass ; to this end it must be under
a considerable head, so as to reach the lower layers ; a pipe led under the blanket

204

THE EXTRACTION OF JUICE BY MILLS.

of megass may be used in addition to the one throwing water on to the upper
surface.*

3. To enable the megass to absorb water readily, it must be finely
crushed ; generally first crushing megass is not fine enough to readily absorb
water.

4. A greater recovery is obtained when the diluent is used in two portions ;
this is sometimes referred to as double maceration.

5. As the mixture of juice and water is not instantaneous, as much time
as possible should elapse between two successive crushings.

6. It is not economical to allow badly crushed megass to pass the first mill
on the supposition that the subsequent wet crushing makes up for the loss ; it
does not.

7. The whole duty of maceration depends on the completeness of the
admixture.

Source of Water for Saturation. — The water which is used in
maceration is conveniently derived from the condensed water in juice heaters,
eliminators, or effects. In the first two, the water being under pressure no
pump is required. If the multiple effect water be used, it is convenient to pump
it to elevated tanks, and thence to allow it to gravitate to the mills. By this
arrangement the water can be measured, a point of considerable importance in
technical control. Very often the maceration water is derived from the hot
water supply for the boilers, a pipe being led from the boiler feed pump to the
mills.

Algebraical Treatment of the Extraction of Juice from
Canes. — Let/ and m denote the fibre per unit weight of cane and of megass ;

then the weight of megass per unit weight of cane is 2- and the weight of

m

juice expressed is ; the weight of juice per unit weight of cane is 1 — /

so that the juice extracted per unit weight of juice in the cane is — m ~" '

ftl-m) ••(*-/)•

The weight of juice remaining in the megass is — and the juice lost in

the megass per unit weight of juice in cane is - — — . As the fibre in

the cane increases, that in the megass remaining constant, the weight of juice
extracted by the mills decreases ; in the annexed table are given values of the

expression for values of / 8 to 1 6 and of m 35 to 45 ; that is to say,

the weight of juice obtained per 100 cane, when the latter contains from 8 per
cent, to 16 per cent, of fibre, and when the megass contains from 35 per cent,
to 45 per cent.

* The distribution of the water by means of injectors as described by L. Pellet at the 1909
Congress of Applied Chemistry would appear to fulfil these requirements ; their use would in
any case be superior to a perforated pipe or to a distributing trough.

205

CANE SUGAR.

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206

THE EXTRACTION OF JUICE BY MILLS.

By dividing the weight of juice obtained by the weight of juice in the
cane, i.e., by 1 — -/, the sugar extracted per unit of sugar in the cane would be
obtained, provided the juice were of uniform composition.

As was originally pointed out by the late Mr. Francis, formerly Govern-
ment analyst in British Guiana, the residual juice in megass is of considerably
less sugar value than that first expressed by the mills. The following figures
obtained by the writer using a small hand mill will give some idea of the
relationship existing between expressed and residual juice : —

Sugar per One part

Percentage cent, in Sugar per residual equal

of juice expressed cent, in to parts of

expressed. juice. residual juice. expressed juice.

74-77 . . 17-34 .. 15-36 . . -885

73-69 .. 17-47 15-20 .. -870

70-46 .. 17-31' .. 14-35 .. -829

65-75 .. 16-43 .. 12-50 .. -762

68-14 .. 16-49 .. 14-63 .. -887

70-63 .. 16-11 .. 12-74 .. -791

66-04 . . 16-69 . . 13-73 . . -824

70-41 .. 16-07 .. 13-17 .. -819

7593 .. 14-86 .. 12-38 .. -833

73-82 .. 13-99 .. 10-73 .. -767

72-08 .. 13-44 .. 11-46 .. -853

69-54 .. 12-88 .. 10-97 .. -852

69-38 .. 17-75 .. 14-02 -789

Mean -830

Let the sugar value of the expressed juice be represented by unity, and
the sugar value of the residual juice by a ; then the sugar value of all the
juice in the cane is given by the expression

m-faf(l-m] _ m + gf — f — gfm

mm m

and the extraction will be given by the formula

m — / m -\- af— f — afm _ m — f

m m m -f- af — f — afm

If to a be given the value -85, it will be found that the extraction corres-
ponding to the weight of juice expressed is about 3 per cent, higher than

that given by the formula — ,-, _ ^^ — extraction.

In 1he table below is calculated the extraction obtained when canes
containing from 10 per cent, to 14*5 per cent, of fibre are crushed to a
megass containing 45 per cent, of fibre, using as a formula the expression,

1-03 (m-f]
extraction = — ^ - >— : —

m (

1 — /

Fibre in cane.

Extraction.

Fibre in cane.

Extraction.

10-0

89-0

12-5

85-0

10-5

88-2

13-0

84-2

11-0

87-4

13-5

83-3

11-5

86-6

14-0

82-5

12-0

85-8

14-5

81-7

207

CANE SUGAR.

Saturation Processes. — Let canes containing / fibre be crushed
till the megass contains m fibre, and to the resulting — megass let w water be

added, the water mixing completely with the residual juice in the megass.

/ / + w m->

The weight of the megass and added water now is— + w =: - — —

and the residual juice in the megass being - - — - , the weight of the

diluted juice i8/(/rc*° + w =f+»™-fm; If this saturated megass be

crushed until it again contains m fibre per unit weight of megass, the weight

f -\-wm- fm wm T_ . ,

of diluted juice obtained is w -i- - — ^— - = » , wm_fm If 1Qstead

of crushing the saturated megass to m fibre, it be crushed to m1 then the pro-

. m1 (/+ wm) — fm
portion of juice obtained of that originally present is — t , „ wm\ _ fm

The use of this method of calculation permits the different schemes for
applying water in saturation processes to be critically examined.

Single Saturation. — By this term is meant a process where the canes,
after dry crushing, are saturated once with water and again crushed. In
the annexed table is calculated, on the lines developed above, the extraction
due to saturation, and the total extraction on the understanding that the megass
contains 45 per cent, fibre in the dry crushing, and 50 per cent, in the saturated
crushing.

The added water is assumed to mix completely with the residual juice and
the latter is taken as having a sugar value equal to *85 of the juice obtained
in the dry crushing.

It follows as a result of the equation, and as can be seen from inspection
of the table on page 209, that as the quantity of added water increases, the
proportionate quantity of sugar obtained due to saturation rapidly decreases ;
further, as the proportion of fibre in the cane increases, the part extracted due
to saturation increases also, so that with high fibre in cane, it is of greater
importance to carefully oversee the admixture of the added water, and to
control as far as possible the fibre in the raw material entering the mill.

Double Saturation. — By this term is meant a process in which the
water is added in two portions, in the case of a nine-roller mill partly after
the first, and partly after the second mill ; in general such a scheme is not
attended with very material benefit with the nine-roller mill, since the megass
coming from the first mill is not in general sufficiently well crushed to absorb
the added water. In a twelve-roller mill, however, material benefit follows
by adding the water in part behind the second, and in part behind the third
mill. In the case of a cane containing 10 per cent, of fibre dry crushed to
45 per cent, of fibre, and then after the addition of 10 per cent, of water with
complete admixture, and crushing to 50 per cent, of fibre, an extraction of

208

THE EXTRACTION OF JUICE BY MILLS.

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209

CANE SUGAR.

95-0 per cent, (see previous Table) is obtained, leaving 5 per cent, in' the
megass ; if, to this megass 10 per cent, water on weight of cane is added with
complete admixture, and the megass be again crushed to 50 per cent, of fibre,

of the sugar remaining ,, . ^m _ » partis obtained; substituting for/ -10, for

m '50 and for w -10 this expression reduces to -5 ; hence of the five parts of
sugar remaining in the megass 2-5 are extracted, and the total extraction
becomes 95-0 + 2-5 •=. 97-5, compared with the 96-6 obtained when the whole
twenty parts of water were added in one portion. This possibility of adding
the water in two equally effective portions is a strong argument in favour of
the twelve-roller mill. In the annexed table is calculated the maximum
extraction to be obtained in a twelve-roller mill, with double saturation and
complete admixture of the added water, which is added in two equal portions
behind the second and third mills. The dry crushed megass is taken as having
45 per cent., and the saturated crushed megass 50 per cent, of fibre. The
result of the calculation shows an advantage in favour of double maceration
of the order of 1 per cent.

Table showing the maximum extraction to be obtained with double maceration
with complete admixture of added water ; dry crushed bagasse containing $.5 per
cent, fibre and saturated crushed bagasse containing 50 per cent, fibre.

Extraction due to saturation in upper, and total extraction in lower, line.

Water added per 100 cane.

100 cane.

20

30

40

50

10-

8-51

9-37

9-85

10-15

97-52 98-38

98-86

99-16

10-5

9-00 9-94

10-47

10-80

97-23 98-17

98-70

99-03

11-

9-49 10-52

11-11

11-48

96-91 97-94

98-53

98-90

11-5

9-94

11-06

11-71

12-12

96-58

97-70

98-35

98-76

12-

10-42

11-63

12-34

12-79

96-24

97-45

98-16

98-61

12-5

10-88 12-19

12-95

13-45

95-88

97-19

97-95

98-45

13-

11-33

12-74

13-57

14-11

95-50

96-91

97-74

98-28

13-5

11-78 13-28

14-18

14-66

95-12 96-62

97-52

98-00

14-

12-23 13-82

14-78

15-41

94-73

96-32

97-28

97-91

210

THE EXTRACTION OF JUICE BY MILLS.

Compound Saturation. — The highest possible efficiency of the-
added water is obtained, when the diluted juice from a later mill is used as a
saturating agent on the megass coming from a previous one ; an algebraical
expression showing the effect of this procedure is not easy to obtain, and
when obtained is not elegant ; the effect of this way of working is best
shown by a worked out example : —

Let canes containing 12 per cent, of fibre be dry crushed to 45 per cent^
of fibre in the first nine rollers of a twelve -roller mill ; let water 30 per cent,
on weight of cane be now added to the megass with complete admixture, and
let the saturated megass be crushed to 50 per cent, of fibre ; then applying
the equations established above, in the dry crushing an extraction of 85-8 per
cent, is obtained, leaving 14-2 per cent, in the megass ; of this 14'2 per cent,
the saturated crushing will in the fourth mill extract 10'4 per cent., so that the
total extraction is 85 8 -f 104 = 96-2 per cent. Let this 10-4 per cent,
contained in the diluted juice be returned to the dry crushed megass ; the
immediate effect of this is to reduce the extraction due to dry crushing from
85-8 to 85-8 — 10-4 = 75'4 leaving 24-6 in the megass ; let this megass be
crushed to 50 per cent, of fibre ; then of the sugar contained in this megass
73-1 per cent, is obtained; -731 x 24*6 = 17'9, so that the extraction at this
stage is 75-4 + 17'9 = 93*3 and 6*7 is left in the megass, which is now to be
saturated with water 30 per cent, on cane, and crushed to 50 per cent, of fibre ,
of the whole amount of sugar now left in the megass 55'5 per cent, is now
extracted; -555 x 6-7 = 3-7, so that the total extraction is 9 3 '3 -f 3*7 = 97*0,
Now let the 3*7 per cent, of sugar contained in the fourth mill juice be
returned to the dry crushed megass ; the extraction due to dry crushing is
now reduced to 85-8 — 3-7 = 82-1, leaving 17'9 in the megass ; as before
73-1 per cent, of this is extracted in the third mill; -731 x 17-9 = 13-1, and
the extraction at this stage is 82-1 + 13*1 = 95% leaving 4*8 in the megass ;.
again let water 30 per cent, on canes be added and 55-5 per cent, of this is-
obtained in the fourth mill ; -555 X 4-8 = 2-7, so that the total extraction is
95-2 + 2-7 = 97-9.

Proceeding in this way and calculating the extraction by a series of steps,,
it is found that each successive addition to the extraction becomes smaller and
smaller, until no appreciable difference is found. In the present case, the
limiting value is found to be practically 98-6. If the water had been added
in two portions, and the diluted juice had not been returned, the extraction
found on similar lines would have been 97-4 per cent.

For purposes of comparison comparative data of the results to be obtained
by different methods of adding the water are given below : —

If canes with 12 per cent, fibre with added water 20 per
cent, on canes give in a nine-roller mill with single
saturation an extraction of 96-2

211

CANE SUGAK.

The same canes with double saturation in a twelve-roller
mill will give an extraction of

And with compound saturation in a twelve -roller mill will
give an extraction of

97-4
98-0

The Effect of an inferior Dry Crushing.— Instead of taking
45 per cent, of fibre in the dry crushed megass, let the percentage of fibre be
40 per cent. Then if the canes contain 12 per cent, of fibre, the extraction due
to dry crushing is 81-93 per cent, leaving 18-07 per cent, in the megass ; let
this megass after the addition of water be crushed to 50 per cent, of fibre .
below is calculated what will be the extraction with single maceration after
the addition of water 10 per cent., 20 per cent., &c., on cane, and for the pur-
pose of comparison the figures already obtained when the dry crushed
megass contains 45 per cent, of fibre are added.

Water added per 100 cane.

10

20

30

40

50

40 per cent, of fibre in dry crushed

megass

92-26

94-29

95-48

96-26

96-80

45 per cent, of fibre in dry crushed

megass . . . .

93-10

95-09

96-19

96-89

97-37

The advantage in favour of the more eifective dry crushing is in reality
greater than is shown in the above calculation ; complete admixture is in both
cases assumed; in practice we do not obtain complete admixture, but the
admixture will be the less imperfect the more the megass is disintegrated;
that is to say, when the fibre content is higher.

The Economic Limit of Saturation.— It is well known that
with each increment of extraction the purity and the amount of available sugar
per 100 sugar extracted also falls; if with an extraction a the proportion of
available sugar is #, and with an extraction of a 4- d the proportion of available
sugar is x — e, it is easy to conceive a state where a x is greater than (a + d)
(x — e) and where (£ a x — expenses) is greater than [_£ (a -\- d) (x — e) —
expenses.] In order to put this conception to the test the writer crushed canes
with the addition of water in a hand mill till over 98 per cent, of the sugar
was obtained ; in all, eight fractions of juice were obtained, each one being
measuied and analysed separately; there was thus obtained the extraction at
eight points together with the available sugar; the available sugar was

calculated from the . ^ _ ^ formula developed in Chapter XXF., giving to*
and m the values 97*5 and 45'0.

212

THE EXTRACTION OF JUICE BY MILLS.

The results of the experiments are as below : —

Fraction.

Weight
per cent.
Cane.

Total
Solids
per cent.

Sucrose
per cent.

Purity.

Value of
*(j—m)

XI AA

j(s-m)

1

34-7

19-10

17-71

92-7

95-5

2

160

19-20

17'23

89-7

92-6

3

13-0

19-04

16-70

87-7

904

4

9-8

13-22

11-64

88-0

90-7

5

11-3

7-22

6-01

83-2

85-3

6

10-0

5-50

4-44

80-8

82-3

7

12-0

4-00

3-16

79-0

79-9

8

11-6

2-86

2-17

75-9

75-7

Megass

28-0

2-05

1-33

65-0

57-3

Kef erring to the above table which represents the mean result of a series
of experiments, the decreasing purity of each successive fraction of juice is
well shown, except at the fourth fraction where an increase over the third is
noticed. This increase, obtained in all the experiments, is not due to accident
or error. The third fraction was obtained under very heavy pressure, and
probably contained much rind tissue juice. The fourth fraction was the first
obtained by adding water to the megass, and probably consisted largely of pith
tissue juice (which had remained unexpressed), to the exclusion of rind tissue
juice as the rind had not yet been sufficiently broken up to take up its
proportion of water.

The following table gives the sucrose obtained in each fraction per 100
sucrose in cane, and in the last column is contained the amount of available
sugar per 100 sucrose in cane.

Fraction.

Sucrose obtained
per 100
Sucrose in cane.

Purity.

Value of
* (j - m)
X 100

Product of
Cols.
2 and 4-^-100

j (s — m)

1

43-2

92-7

95-5

41-3

2

19-1

89-7

92-5

17-8

3

15-1

87-7

90-4

13-8

4

8-0

88-0

90-7

7-3

5

4-7

83-2

85-3

4-0

6

3-0

80-8 82-3

2-5

7

2-6

79-0

79-9

2-2

8

1-7

75-9

75-7

1-3

Megass

2-6

69-0

57-3

1-5

The third table gives the extraction at any point, the purity and
proportion of available sugar, and the available extraction, i.e., the available
sugar per 100 available sugar in the cane.

213

CANE SUGAE.

Extraction.

Purity.

Value of

s (j - m)

XI C\C\

Available
Extraction .

j (s — m)

43-2

92'7

95-5

45-0

62-3

91-9

94-7

64-4

77-4

9M

94-0

79-5

85-4

90-8

93-7

87-4

90-1

90-4

93-2

91-8

53-1

90-1

92-9

94-4

4)5-7

89-8

92-6

96-9

37-4

89-5

92-3

98-4

100-0

88-9

91-7

100-0

Assuming that with lower initial purities the decrease in purity is pro-
portional to that already found, in the four tables below are calculated the
same data as in the two preceding tables for initial purities of 80 and 85.

Fraction.

Sucrose obtained
per 100
Sucrose in cane.

Purity

Value of

JM**

Product of Cols.
2 and 4 -r 100.

1

43-2

85-0

87-4

37'9

2

19-1

82-2

84-0

16-1

3

15-1

80-4

81-7

12-3

4

8-0

80-7

82-0

6-6

5

4-7

76-3

76-2

3-6

6

3-0

74-1

72-9

2-5

7

2-6

72-4

70-3

1-9

8

1-7

69-6

65-6

1-2

Megass

2-6

59-6

45-5

1;2

Extraction.

Purity.

Value of

Available
Extraction.

j(s-m)X

43-2

85-0

87'4

45-7

62-3

84-1

86-3

65-1

77-4

83-4

85-5

79-9

85-4

83-1

85-1

87-8

90'1

82-8

84-8

92-2

93-1

82-5

84-4

94-9

95-7

82-2

84-0

97'5

97-4

82-0

83-8

98-7

100-0

81-4

83-0

100-0

214

THE EXTRACTION OF JUICE BY MILLS.

Fraction.

Sucrose obtained
per 100
Sucrose in cane.

Purity.

Value of

7^5 -»

Product of Cols.
2 and 4 -f 100.

1

43-1

80-0

81-2

35-2

2

19'1

77-4

77-7

14-8

3

15-1

75-7

75-3

11-5

4

8-0

75-9

75-6

6-0

5

4-7

71-8

69-3

3-3

6

3-0

69-7

65-7

2-0

7

2-6

68-2

63-2

1-7

8

1-7

65-5

58-1

1-0

Megass

2-6

56-1

36-7

1-0

Extraction.

Purity.

Value of
s (j — m)

Available
Extraction.

j(s-m) X100'

43-2

80-0

81'2

46-0

62-3

79-2

80-1

65-4

77-4

78-5

79-2

80-4

85-4

78-3

78-9

88-2

90-1

77-9

78-4

92-6

93-1

77-7

78-1

95-1

95-7

77'4

77-6

97'4

97-4

77-2

77-3

98-7

100-0

76-6

76-5

100-0

The results so obtained lend themselves to graphic representation. In
Fig. 130 is plotted on the horizontal line the total extraction at each point,
and on the vertical line the purities and amount of available sugar in the
whole quantity of juice extracted. The product of the height of the available
sugar curve at any point into the extraction at that point represents the
available extraction at that point.

In no case is there reason to suppose that increasing the extraction will
decrease the amount of available sugar due to a lower purity.

As regards the second conception stated above, local conditions are the
dominant determining factor ; the writer's attempt to solve the question was
made for conditions as they were in certain factories in Mauritius, circa 1902,
and is reproduced below from ' Sugar and the Sugar Cane.' It cannot le too
strongly insisted on that those interested should make the calculations themselves,
using their oivn choice of data.

215

CANE SUGAR.

g | !5

<^

I

Purif-y, or °/o /Jvai/able Sugar.

O) -J CD

o o o

Oi

216

THE EXTRACTION OF JUICE BY MILLS.

The chief factors in determiniDg the economic limit are7 : —

1 . The type of crushing plant, whether two or three mills.

2. The degree of admixture of the added water.

3. The proportion of sugar extracted for market on the total brought
into the juice as the result of maceration.

4. The thermal efficiency of the factory as a whole, including the boiler
plant, the method of evaporation, triple or quadruple effect, and the general
internal economy.

5. The money value of the marketed sugar.

6. The cost of coal or other fuel.

7. The fuel value of the extra sugar extracted.

8. The expenses of making, handling, transporting, &c., the extra sugar
made.

9. The sugar content of the cane.

10. The cost of the increased evaporating and other plant to deal with
the larger quantities of juice.

An attempt follows to unite all these factors into one expression.

Following on what has already been written, it is simply a matter of
calculation to find what amount of extra sugar is extracted as the result of
added water ; for this purpose the following data have been adopted : — ]

Canes (a).— 13'69 per cent, sugar, 12*00 per cent, fibre, crushed in the
first mill to 30 per cent, fibre give 60 per cent, of juice, containing 16-15 per
cent, sugar ; crushed further in a second mill to 45 per cent, fibre give
13-33 per cent, of juice, containing 15-34 per cent, sugar. The residual
megass 26*67 per cent, on the canes contains 14*67 juice per cent, on cane,
the juice containing 13*40 per cent, sugar.

Canes (i).— 10-26 per cent, sugar, 12-00 per cent, fibre crushed as in the
above case, give first mill juice 12-07 per cent, sugar, second mill juice
11*46 per cent, sugar, residual juice in megass 10-20 per cent, sugar.

To the megass from canes of the above composition let water be added
after the second crushing, and let the megass be again crushed to the same
fibre content. The amount of diluted juice obtained is evidently the same as
the water added, and the amount of sugar brought into the juice can be easily
calculated when the coefficient of admixture is known. In calculating the
tables below a coefficient] of -85 has been adopted, and of the sugar thus
brought into the juice -85 is estimated as capable of extraction as marketable
sugar. The value of this sugar is taken as £9 per ton or 1-90 cents per pound.
The expenses of obtaining this sugar are ascertained on the following basis :
The composition of the expressed diluted juice is calculated allowing a purity
of 80 ; the tons of water necessary to be evaporated to concentrate this to 50°
Brix, and then to masse cuite at 95° Brix, are calculated. Coal is taken
as worth £2 at the furnace mouth, and to give for use in the factory per lb.
burnt 8 Ibs. steam, each 1 lb. capable of evaporating 3 Ibs. in the triple and

217

CANE SUGAR.

of Ca

218

THE EXTRACTION OF JUICE BY MILLS.

1 Ib. in the pans ; for heating the extra juice each ton is regarded as requiring
•016 ton coal. The expenses of evaporation are thus obtained. On reference
to the tables below it will be seen that these expenses are practically
constant for the different types of cane and crushing when the added water
is the same, and that one ton of coal will, with the data adopted, account
for twenty tons added water. If w tons water be added, the expenses are then
'w£ per 100 tons canes for heating and evaporation of extra juice.

The total amount of sugar washed out of the megass as the result of the
maceration is calculated before the amount of marketed sugar is obtained ; the
sugar is valued as fuel at £1 per ton, with coal at £2 per ton, and to the values
so obtained 10 per cent, is added to express the fuel value of other organic
combustible removed. With the data adopted the value of the sugar, &c., as
fuel is '144 of the sugar markets. The other expenses, packages, handling,
transport to port, &c., are estimated at 10s. per ton or *055 of the value of the
sugar marketed ; the sum total of these last two sources of expenditure is then
almost exactly '2 of the value of the sugar marketed. The general expression
then to give the value of maceration with the data adopted is : Net profit =-
£7'2$ — -w£ per 100 tons of cane, S being the tons of sugar marketed, and w
the tons of water added.

When only two mills are used, very different results are obtained; the
method of calculation employed is then somewhat different. After the canes
have been crushed to 30 per cent, of fibre, water is supposed to be added, and the
megass crushed to 45 per cent, of fibre ; the sugar obtained is calculated on the
supposition of complete admixture ; the excess over that obtained by simple
dry crushing to the same fibre content has already been given, and 85 per cent,
of this excess is taken as the extra sugar brought into the juice as the result
of maceration. The other calculations are made as detailed above.

The results of these calculations just indicated are given in the appended
tables, and are also expressed as curves in Figs. 131 and 182. The curve
marked 'gross' represents the value of the extra product obtained at £9 per ton,
and the curve marked ' expenses ' gives the expenditure, and that marked
* economic ' the profits.

Three points bearing on the subject have not been included in the above
calculations. Firstly, no allowance has been made for decreased purity of
the juice ; in the writer's experience this is not serious. Secondly, no
allowance has been made for increased consumption of steam to drive
the third mill. With a modern engine, and where the exhaust is used in
evaporation, this is a small item. And, thirdly, there is the question of in-
creased initial cost for enlarged boilers and evaporating plant. Referring to the
4 economic ' curves it will be seen that as the curves approach the maximum,
the increase in the profits is very slow. In designing a new plant, this might
well indicate the financial economy of arranging for a dilution of from 5 per cent,
to 10 per cent, less than the indicated maximum.

219

CANE SUGAR.

ds h.e.-

«/Ca.-»e

fc

fOO ZO

ft)

220

THE EXTRACTION OF JUICE BY MILLS.

On examining the tables and curves it is at once apparent that the main
factor in determining the economy is the relative value of sugar and coal; any
variation from the ratio adopted here entirely alters the conditions, and an
unfavourable alteration might easily, in the case of a poor cane and two mills,
convert the estimated profits into a loss. The second point to be noticed is that
whatever the admixture, the expenses of evaporation remain the same ; a lower
coefficient than that adopted here would also in many cases, indicate a loss.
Thirdly, the great financial profit due to a third mill is clearly shown.

CANES 13-69 PER CENT. SUGAR. THREE MILLS.

Cost or Value of in £ Sterling.

Tons added Water per 100 tons of Cane.

5

10

15

20

25

30

35

Heating and evaporation

•53

1-05

1-57

2-06

2-57

3-08

3-56

Handling, packages, transport, &c.

•18

•29

•36

•41

•44

•47

•50

Sugar, &c., as fuel

•47

•74

•93

1-06

1-16

1-23

129

Total expenses

1-18

2-08

2-86

3-53

4-17

4-78

5-35

Marketed sugar

3-24

5-18

6-45

7-37

8-05

8-56

9-01

Profits .-. ...

2 06

3-10

3-59

3-84

3-88

3-78

3-66

CANES 13-69 PER CENT. SUGAR. Two MILLS.

Tons added Water per 100 tons of Cane.

Cost or Value of in £ Sterling.

5

10

15

20

25

30

35

Heating and evaporation

•51

1-04

1-55

2-06

2'55

3-07

3-54

Handling, packages, transport, &c.

•06

•14

•20

•25

•29

•32

•35

Sugar, &c., as fuel

•20

•47

•69

•84

•98

1-04

1-16

Total expenses

•77

1-65

2-44

3-15

3-82

4-43

5-05

Marketed sugar

1-14

2-66

3-86

4-80

5-49

6-11

6-57

Profits

•37

1-01

1-42

1-65

1-67

1-63

1-52

CANES 10-26 PER CENT. SUGAR. THREE MILLS.

Tons added Water pen- 100 tons of Cane.

Cost or Value of in £ Sterling.

5

10

15

20

25

30

35

Heating and evaporation

•53

1-03

1-56

2-06

2-56

3-07

3-56

Handling, packages, transport, &c.

•13

•22

•27

•31

•34

•36

•38

Sugar, &c., as fuel

•35

•66

•83

•95

1-04

1-10

1-16

Total expenses

1-01

1-91

2-66

3-32

3-94

4-53

5-10

Marketed sugar

2-36

3-93

4-89

5-61

6-03

6-54

6-93

Profits

1-25

2-02

2-23

2-29

2-09

2-01

1-83

221

CANE SUGAR.

CANES 10-26 PER CENT. SUGAR. Two MILLS.

Cost or Value of in £ Sterling.

Tons added Water per 100 tons of Cane.

5

10

15

20

2o

30

35

Heating and evaporation

•49
•05
•17
•71
•97
•26

•99
•11
•42
1-52
2-07
•55

1-46
•16
•54
2-16
3-06
•90

2-03
•19
•67
2-89
3-69
•80

2-55
•22
•76
3-53
4-25
•72

3-04
•24

•85
4-13
4-70
•57

3-53
•27
•92
4-72
5-13
•41

Handling, packages, transport, &c.
Sugar, &c., as fuel
Total expenses
Marketed sugar
Profits

The Structure of the Cane as affecting Milling.— The

very brief account of the cane given in Chapter I. will have shown that it is
of a very complicated structure ; the three principal structures are the rind,
the pith, and the fibre-vascular bundles. From the milling point of view the
cane may be regarded as composed of rind, pith, and nodes, the last being
intermediate in composition between the two first. The writer made a number
of analyses of canes, dividing them into rind, pith, and nodes. The results
are as shown in the following table : —

Rose
Bamboo.

Y. Cale-
donia.

Lahaina.

Lahaina

Y. Cale-
donia.

Oaliu.

Oahu.

Oahu.

Maui.

Kauai.

Whole Cane.

Weight per cent, cane

100-00

100-00

100-00

100-00

100-00

Juice per cent

87-12

84-91

86-25

88-40

84-45

Fibre per cent.

12-88

15-09

13-75

11-60

15-55

Solids per cent

14-70

15-83

16-03

20-10

17-92

Sugar per cent

13-25

13-04

13-28

18-14

15-36

Water per cent

72-12

69-08

70-22

68-30

66-53

Pith.

Weight per cent, cane .

74-28

66-90

72-45

61-77

67-15

Juice per cent

91-90

90-43

90-11

94-78

91-20

Fibre per cent

8-10

9-87

9-89

5-22

8-80

Solids per cent

15-93

17-34

17-45

22-21

19-62

Sugar per cent

14-80

15-06

15-11

21-11

17-52

Water per cent

75-97

73-09

72-66

72-57

71-60

Bind.

Weight per cent, cane .

9-57

15-27

12-28

14-34

15-80

Juice per cent

62-11

65-92

72-73

69-98

64-92

Fibre per cent

37-89

34-71

27-27

30-02

35-08

Solids per cent

9-38

11-52

11-54

15-40

13-87

Sugar per cent

6-46

7-44

7-50

11-10

10-00

Water per cent.

52-73

53-77

51-19

57-58

51-05

Node.

Weight per cent, cane .

16-15

17-83

15-27

23-89

17-05

Juice per cent

79-98

80-40

78-78

82-80

75-97

Fibre per cent

2002

19-60

21-22

17-20

24-03

Solids per cent.

12-22

13-86

12-88

17-43

15-07

Sugar per cent

10-14

10-27

9-22

14-62

11-83

Water per cent

67-76

66-54

65-90

65-37

60-90

222

THE EXTRACTION OF JUICE BY MILLS.

Rose
Bamboo.

Y. Cale-
donia.

Lahaina.

Lahaina.

Y. Cale-
donia.

Oahu.

Oahu.

Oahu.

Maui.

Kauai.

Absolute Juice.

Weight per cent, cane .
Solids per cent
Sugar per cent

87-12
16-87
15-22

84-91
18-52
15-35

86-25
18-59
15-39

88-40
22-72
20-52

84-45
21-22
18-19

Purity . .

90-22

82-94

82-79

90-32

85-71

Pith Juice.

Weight per cent, cane .
Solids per cent
Sugar per cent.

68-26
17-33
16-10

60-49
19-17
16 65

65-49
19-37
16-76

58-62
23-43
22-27

61-24
21-49
19-20

Purity

92-90

86-85

86-53

95-05

89-29

Rind Juice.

Weight per cent. cane.
Solids per cent
Sugar per cent
Purity

6-04
15-08
10-40
69-10

10-06
17-41
11-29
64-85

8-91

15-87
10-30
64-91

10-00
22-00
15-86
72-09

10-26
21-37
15-40
72-10

Node Juice.

Weight per cent. cane.
Solids per cent
Sugar per cent

12-82
15-28
12-68

14-36
17-24
12-77

11-85
16-29
11-70

19-78
21-05
17-66

12-95
19-83
15*57

Puritv .

82-98

74-07

71-81

83-90

78-50

Canes very similar to those used in the above described experiments were
then crushed in a hand mill ; the megass was divided into two parts, one
representative of the pith and one of the rind ; these were weighed and
analysed separately with the results shown below : —

Lahaina.

Rose Bamboo.

Y. Caledonia.

Y. Caledonia.

Maui.

Oahu.

Kauai.

Oahu.

Expressed Juice.

Weight per 100 cane ....

70-99

66-75

65-60

64-64

Solids per cent

24-22

17-70

21-68

18-73

Sugar per cent

21-94

16-42

18-42

16-85

Purity

90-58

92-77

84-97

89-96

Pith Megass.

Weight per 100 cane
Solids per cent

13-35
15-29

15-74
11-57

14-40
12-20

14-69
12-20

Sugar per cent

13-46

10-32

9-00

10-00

Water per cent.

52-32

56-16

49-21

54-52

Fibre per cent

31-39

31-27

38-59

33-28

Rind Megass.

Weight per 100 cane ....

15-66

17-51

20-00

20-67

Solids per cent.

13-26

9-40

11-09

9-92

Sugar per cent

10-37

7-22

7-45

5-68

Water per cent

53-90

54-00

46-68

49-97

Fibre per cent. .

32-84

36 60

42-23

40-11

223

CANE SUGAR.

This experiment shows that with a ' crushing ' up to 70 per cent, very
little ' rind juice ' is extracted.

Megass collected from factories was also divided into two parts representa-
tive of the pith and rind ; each part was analysed separately with the
following results : —

Mill 1.

Mill 2.

Mill 3.

Mill 4.

Pith Megass.

Weight per 100 megass. .

53-33

48-62

50-0

51-25

Sugar per cent

11-33

7-19

3-78

2-87

Fibre per cent

33-59

41-58

45-63

46-91

Rind Megass.

Weight per 100 megass

46-67

51-38

50-0

48-75

Sugar per cent. .

9-12

7-13

4-34

4-06

Fibre per cent -.

35-15

41-54

44-90

46-67

Whole Megass.

Weight per 100 megass. .

100-0

100-0

100-0

100-0

Sugar per cent

10-34

7-16

4-06

3-51

Fibre per cent. . . ;.'• ..

34-32

41-56

45-26

46-87

These analyses bring out the fact that the pith megass, originally
the sweetest, is much more extracted than the rind megass, from which the
process of milling has taken comparatively little sugar.

These results are approximately summarized in the following table which
•conceives the cane as composed of pith and rind, from the former of which a
high extraction is obtained, a very efficient one resulting from the hard
impervious rind : —

Mill 1.

Mill 2.

Mill 3.

Mill 4.

Extraction per

100 sugar in pith. .

91-6

95-7

97-9

98-5

,,

,, cane .

78-5

82-0

83-9

84-5

»»

,, rind .

22-2

48-3

71-0

73-9

5 1

,, cane. .

3-2

6-9

10-1

10-5

Total

» » • •

81-7

88-9

94-0

95-0

REFERENCES IN CHAPTER XI.

1. La. Planter, xli., 299.

2. La. Planter, xxxvii., 261.

3. Arch., 1896, p. 222.

4. Proc. Inst. Mech. Eng., Nov., 1902.

5. After Bull. 22. Agric. H.S.P.A.

6. After Ball. 30. Agric. H. S. P. A.
1. I.S.J., 68.

224

CHAPTER XII.

THE DIFFUSION PKOCESS.

In the process described in the previous chapter the juice is extracted
from the cane by rupture of the cells which contain the juice. In the
diffusion process an entirely different system of extraction is carried out, the
principle of which is as under : — If a solution of a soluble body such as sugar
contained in a cell, the walls of which consist of some porous material, for
example, unglazed earthenware, parchment, or the woody cells of which
plants are built up, be immersed in a vessel of water, it is found that the
sugar solution passes out through the porous wall into the water and that
water enters the cell ; this process continues until the solution on both sides
of the cell is the same. It is not all bodies that possess this property. Those
which do not, for example, gummy bodies, are termed colloids, and in general
it is found that it is crystalline bodies that possess the property of passing
through a porous membrane ; to this phenomenon the name of osmosis or
diffusion is given.

The sugar cane consists of a vast number of cells, in the interior of which
the juice is contained ; and the diffusion process applied to the extraction of
juice consists of systematically allowing the juice in these cells to diffuse into
water or diluted juice. In the diffusion process the cane is cat into fine slices
about one-twentieth of an inch thick. These slices, technically called chips,
are placed in vessels known as cells or diffusers, and are systematically washed
until a very high degree of exhaustion is obtained. The system of working
is roughly this : Suppose that there are twelve cells in use, these are all
connected so that juice from one cell can be passed on to the next succeeding
one ; into a cell fresh chips are introduced ; water that has passed over eleven
sets of chips is forced into this cell, and after diffusion has taken place a charge
of juice is withdrawn, and water which has passed over ten sets of chips takes
its place. This process continues until water alone enters the cell. The
highly diluted juice passes on in the above-described routine, and the chips are
discharged to be, in general, crushed in a mill to remove water before use as
fuel.

The essential parts of a diffusion plant are described below.

Cane Cutter. — A type of cane cutter that has been largely used is
shown in vertical section in Fig. 183; on a vertical spindle b, belt-driven from
the pulley d, by means of the bevel wheels c, is carried a disc e. The whole

225

15

CANE SUGAR.

is enclosed in a sheet iron casing h and closed by a strong cover g ; fastened on
to the disc e are a number of boxes varying from six to twelve, each of which
carries a strong sharp knife. The knives are fixed on the disc exactly similar
to the cutting edge of a carpenter's plane, and the knife boxes are arranged so

FIG. 133.

that they may readily be removed from the disc and spare knives substituted
when one set has become blunted. A plan of the disc with an arrangement
of twelve knives is shown in Fig. ISIj.. Securely fixed to the cover are one,
two or more hoppers a into which are fed the canes, which descend on to the
disc by their own weight. A high speed is given to the disc, from 100 to 15Q

226

THE DIFFUSION PROCESS.

revolutions per minute, and the knives cut the cane into chips one-twentieth
of an inch or more in thickness, dependent on the setting of the knives. The-
hoppers are made either vertical or at an angle — the former giving round and
the latter oval chips. The chips fall into the receptacle formed by the sides-
of the apparatus below the disc, and thence pass on to the shoot. The cutter
is variably placed above or below the diffusion battery. Cane cutters of this
type differ in details. They are sometimes directly driven without the inter-
position of belt gearing, and are also sometimes over instead of under-driven,,
as shown in Fig. 133. The shoot t is also sometimes dispensed with and its
place taken by a scraper actuated by the shaft b. In this case the bottom of
the receptacle h is flat, or nearly so, and the chips are swept out through an
opening in the bottom.

FIG. 134.

To work up 300 tons of cane in twenty-four hours, a plant of this nature
will be about 5 ft. in diameter. The capacity depends on the number of
hoppers, and on the setting of the knives, whether to give thick or thin chips.
More cane can be cut when thick chips are allowed, but the efficiency of the
after process of diffusion is diminished.

Diffusion Cell. — A section through a cell of a diffusion battery, along
with its accompanying juice heater, is shown in Fig. 135. It consists of a
cylindrical vertical shell, the bottom being made with a slight slope, and the
top fitted with a head box ; the cell is closed by a door on the top, which is
clamped tight by the screw and lever shown at b ; by slackening the screw
the door can be slung on one side, to allow of a charge of chips being intro-
duced. Round the bottom part of the cell is fixed a perforated false bottom dr

227

CANE SUGAR.

the object of which is to prevent pieces of cane being carried along the pipe c.
In some designs the lower door itself carries the false bottom. The joint in
the lower door is a hydraulic one, consisting of a hollow rubber tube provided
with a pipe by means of which water is conducted to the tube, which is placed

FIG. 135.

in a circular groove contrived either in the door itself or in the bottom of the
cell. The water which fills this tube is taken from a tank at a high level, so
that in all cases the pressure in the tube is greater than the pressure in the
cell. In other cases the rubber tube is connected by a pipe with the main

228

THE DIFFUSION PROCESS.

steam ; the direct steam becomes condensed in the coil, and pressure is made
in the rubber tube by the steam acting on the condensed water.

Attached to each cell or dipper is the juice heater b ; this is of the verti-
cal tube type, exhaust steam being admitted at o, and the condensed water
drawn off at p. Communication between diffuser and juice heater maybe
made either at top or bottom by the pipes k or c. The main juice circulating
pipe is shown at m, the controlling valves or cocks appearing at i. The floor
level on which the operator stands is at the line I, all valves and cocks being
within easy reach ; g is a small pipe let into the cover of the diffuser to act as
an air vent to allow the air to escape when the diffuser is being filled.

Elevators. — The other adjuncts of the diffusion battery which remain
to be described are the elevator and charging apparatus ; these are very varied
in design and arrangement. In case the canes are sliced on the basement,
they are elevated to a floor above the level of the battery by means of an end-
less scraper carrier similar to those employed to convey megass to the boilers ;
in other cases, the cane cutting machine is placed above the level of the
diffusion battery, and the canes are elevated as such, and the sliced cane dis-
tributed directly from the cutting machines,

Charging. — The method by means of which the cells are filled with
chips varies with the arrangement of the battery ; the latter may be arranged
either as a circular or as a line battery. In the former case the cutter is placed
about twenty feet above the level of the top of the cells and directly over the
centre of the battery, or in case the canes are cut on the basement the chips
are elevated to a hopper similarly placed. The hopper or cane cutter is mounted
on rollers, so that it can be revolved through a complete circle. The hopper
terminates in a shoot, the discharge of which can thus be brought over any cell
at will. When the cells are placed in line, the chips cut on the basement are
delivered into a truck running on an over-head line, from which pass shoots
directing the chips to the diffusers. Line batteries are generally placed in two
parallel rows, between which is the platform on which the attendants stand.

Circulation. — The water requisite for the diffusion process is contained
in an overhead tank, placed considerably above the level of the diffusers. The
circulation of juice throughout the battery is secured by means of the hydrostatic
pressure obtained from the head of water in this tank. When it is desired to
empty a cell of its liquid contents, this hydrostatic pressure cannot of course be
used, and an air compressor, in nearly all cases, forms a part of the plant. The
latter is used also in starting the first round of the battery, and afterwards in
the regular routine when a cell contains exhausted chips.

Working of the Battery.— In Fig. 136 is given a plan of a
twelve- cell line battery, arranged in two rows, showing the pipe connections
between cells and heaters, and in Fig. 137 a diagrammatic sketch of a battery
intended to illustrate the method of working. Let the battery consist of twelve

229

CANE SUGAR.

elements which may be arranged as a line or circular battery. The pipe line
W represents the water main connected to the overhead tank, and that marked
J the juice main. Let it be cell No. 1 that is the first to be filled with chips ;
the three or four last cells of the battery are first filled with water. To do
this the cock W9 is opened, and water flows into cell No. 9. When No. 9 is
three-parts full the top door is closed, and as soon as water escapes through the
air vent the valve W 9 is closed. No. 10 is now filled, but in a different
way ; the valves J9 and J 10, are opened and also W 9. Water then flows from
cell No. 9 up juice heater No. 9, through the valves in the juice main J9 and
J10, down juice heater No. 10 and up into diffuser No. 10. It will be seen
that water passes through two juice heaters and enters the cell from the bottom ;
in this way the air is free to escape. This method of filling a cell is termed in
French meichage. Cells Nos. 11 and 12 are then filled in a precisely similar
manner. During the passage of the water through the juice heater it is heated
and enters the cells at a temperature of about 200° F.

By this time cell No. 1 will have been filled with chips, and is now ready
to receive hot water from cell No. 12. The water is passed into cell No. 1 in
the manner described as meichage, as soon as juice passes out through the air
vent. The direction of the flow of water is reversed by closing the valve J 12
.and opening the circulation valve C12, so that the flow is now from top to
bottom.

In the meantime, cell No. 2 has been filled with chips, and the operations
•described in connection with cell No. 1 are carried out in a precisely similar
manner. "When five or six cells have been filled with chips in this way, those
that were at first filled with water are emptied. To do this, the hydrostatic
pressure is replaced by air pressure from the air compressor, the water connect-
ions being shut off. When cell No. 6 has been filled with chips and water, the
first charge of juice is drawn. To do this the direction of the flow is changed
in this cell from top to bottom, the circulation valve is opened and the juice
valve shut; at the same time the valve connecting the juice main to the
measuring tank is opened. The juice from cell No. 6 will flow along the juice
main under either the influence of hydrostatic pressure from the overhead tank
or air pressure from the air compressor. When the proper amount of juice has
been drawn, the valve leading from the juice main to the measuring tank is
closed, and cell No. 7 is filled by meichage. The chips in cell No. 1 are now
exhausted, the door at the bottom is opened and the chips are discharged on to
a carrier, which conveys them to a mill where they are crushed and passed on
to the boiler wall for fuel.

After the first charge has been drawn from cell No. 6, a charge is drawn
from cell No. 7, and so on from each cell of fresh chips until that cell is
reached which was the first to be filled with chips. The first round of the
battery is now complete, and the regular routine recommences. Two cells are
always out of circuit, one filling and one being prepared for fresh chips.

230

THE DIFFUSION PROCESS.

Each time a cell is filled with fresh chips a charge of juice is drawn and a cell
of exhausted chips emptied.

The following notes on the quantity of juice to draw are taken from
Spencer1 : —

" With a constant percentage of sucrose in the normal juice, a uniform
draw and a perfectly regular extraction, the dilution and consequently the per
cent, sucrose in the diffusion juice will vary considerably. This variation is
due to the variable juice content of the cane. In ordinary seasons in

231

CANE SUGAR.

Louisiana the per cent, juice in plant cane will average about 91, and in
stubble (ratoons) about 89, consequently if we draw the same amount of juice
when diffusing cane as we do with stubble, the dilution will be lower, and the
analyses of the two juices will vary, even though the normal juices contain
the same per cents, of sucrose. It is safe to commence working with a dilu-
tion of about 23 per cent., estimating on a average about 90 per cent, of juice
in the cane. If the extraction is satisfactory, but the density of the diffusion
juice too low, the cane contains less than 90 per cent, of juice, and the draw
should be reduced until a satisfactory density is obtained. With thin chips
and regular work the draw may be reduced to 18 per cent., but it is not safe
to go beyond this limit, except when there is a careful chemical control to
promptly detect and remedy a poor extraction. With the best multiple effect
evaporation it is economical to burn more coal to evaporate additional water
rather than leave two to three-tenths per cent, sugar in the chips, which
might have been obtained by a little higher dilution."

The following table, designed for preliminary work, gives the dilution for
different quantities of juice drawn : —

Table showing the apparent dilution of the normal juice corresponding to different
quantities of juice drawn.

(This table is based on assumed juice content in the cane of 90 per cent,
and of an average density of 16° Brix.)

Apparent
Dilution.
Per cent.

Diffusion Juice Drawn per
100 Ibs. Cane.

WIJ§*t Gallons. Litres.

Apparent
Dilution
Per cent.

Diffusion Juice Drawn per
100 Ibs. Cane.

WH§?t Gallons. Litres.

10 ..

99-0

.. 11-2 ..

42-3

21 . .

108-9

.. 12-4 ..

46-9

11 ..

99-9

.. 11-3 ..

42-7

22 ..

109-8

.. 12-5 ..

47-2

12 ..

100-8

.. 11-4 ..

43-1

23 ..

110-7

.. 12-6 ..

47-6

13 ..

101-7

.. 11-5 ..

43-5

24 ..

111-6

.. 12-7 ..

48-0

14 ..

102-6

... 11-6 ..

43-8

25 ..

112-5

.. 12-8 ..

48-4

15 ..

103-5

.. 11-7 ..

44-2

26 ..

113-4

.. 12-9 ..

48-8

16 ..

104-4

.. 11-8 ..

44-6

27

114-3

. . 13-0 . .

49-1

17 ..

105-3

. 11-9 ..

45-0

28 ..

115-2

.. 13-1 ..

49-5

18 ..

106-2

. . 12-0 ..

45-3

29 ..

116-1

.. 13-2 ..

44-9

19 ..

107-1

12*2

46-1

30 . .

117-0

.. 13-4 ..

50-6

20 ..

108-0

. . 12-3 ..

46-5

Temperature. — A very important point in connection with diffusion
work is the temperature to which the juice should be heated. The following
temperatures are given by Llewellyn Jones2 as prevailing in the diffusion
battery at Non Pareil in Demerara :— No. 1, 75°C.-80°C. ; No. 2, 80° C.
—85° C. ; No. 3, 85° C.— 90° C. ; No. 4, 95° G.— 100° C. ; Nos. 5-9, 100° C. ;
No. 10, 90° C.; No. 11, 85° C.

232

THE DIFFUSION PROCESS.

233

CANE SUGAR.

At the United States Government experiment station at Magnolia during
the season 1888-89 the following were the temperatures maintained : —
Cell No. 1 2-7 8-10 11 12

Temp. F.° 140 158-176 203 185 160

The temperature and densities in the different cells at Wonopringo, Java, are

shown in the following table : —

Degree Sugar Tempera-
Cell. Density. Brix. Percent. Purity. ture °C.
Normal juice 1-067 .. 16-4 .. 14'55 .. 87'50 .. —

1 1-054 .. 13-4 .. 11-66 .. 87-01 .. 69

2 1-036 .. 9-0 .. 7'53 .. 83-66 .. 77

3 1-028 .. 7-1 .. 5-95 .. 83'80 .. 92

4 1-023 .. 5-8 .. 4'64 .. SO'OO .. 91

5 1-019 .. 4-9 .. 3-88 .. 79-18 .. 89

6 1-015 .. 3-9 .. 3-09 .. 79-23 .. 88

7 1-013 .. 3-4 .. 2-67 .. 7S'52 .. 87'5

8 1-010 .. 2-6 .. 1-98 .. 76-15 .. 88

9 1-007 . 1-9 1*42 .. 74-73 .. 87

10 1-005 .. 1-4 .. 1-02 .. 72-85 .. 90

11 1-004 .. 1-1 .. -85 .. 77-27 .. 92

12 ... 1-0015 .. -4 .. -29 .. 72-50 .. 92

13 1-0003 .. -15 .. -06 .. 40-00 .. 91

It is in the cells last in series — i.e., those containing the fresher chips —

that the temperature should be highest; the higher the temperature the better
the diffusion, and by maintaining a high temperature in the last cells, these are
made to do as much work as possible.

Influence Of Number Of Cells.3 — As the number of cells in a
battery increases, so also does the extraction, the amount of water used
remaining the same ; simultaneously the dilution decreases. Thus with mill
juice of 19° Brix in a 10-cell circuit the juice drawn off was of 13'1° Brix, but
with a 16-cell circuit it was of 16-0° Brix. These figures were obtained in an
experimental trial in Java in 1885. An insufficient number of cells seems to
have been a weak point in the design of several of the Naudet outfits (v.
infra).

Difference between Mill and Diffusion Juice.— Diffusion
juice is invariably purer than the juice extracted by milling. In milling, the
joints of the cane and the fibro-vascular bundles are ruptured and afford a juice
much less pure than that given by the pith cells. In diffusion the gummy
matters diffuse less quickly than the sugars, and owing to the high temperature
a portion of the albuminoids is coagulated within the cell, and does not pass
into subsequent processes. This point is illustrated by the following analyses

from a Cuban factory working mills and diffusers simultaneously : —

Krajewski First Second

Breaker. Mill. Mill. Diffusion.

Density 1-088 .. 1-080 .. 1'078 .. 1-062

Sugar, Volume per cent. 20'43 .. 18'62 .. 17'80 .. 14-83

Glucose ,, -34 . . '33 . . -33 . . -28

Non-sugar „ 2-01 .. 2-25 .. 2-54 .. 1-32

Purity 89-7 . . 87'8 . . 86-5 . . 90-3

234

THE DIFFUSION PEOCESS.

Comparison between Milling and Diffusion. — The diffusion
process as applied to the cane sugar industry first came into prominence about
1884, and since that date it has received extended trials ; amongst the plants
that have been erected may be cited those at Non Pareil in Demerara, at
Britannia in Mauritius, at Makaweli and Kealia in the Hawaiian Islands, and
at Wonopringo in Java ; these factories, all of which were worked under
expert supervision, have nevertheless reverted to milling, and the same is true
of the majority of diffusion plants that have been erected. However,
diffusion cannot be considered as dead, as several of the older plants remain in
successful operation, and a few others have been erected in recent years. The
causes that contributed to the non-success of the earlier diffusion plants were : —

1. Faulty design on the part of the engineering firms responsible for the
machinery ; this was especially pronounced in connection with the cane
cutting machinery.

2. Difficulty in maintaining a constant supply of cane for day and night
work. In a diffusion process, it is essential that the work be continuous ;
with milling this is not the case as the process of extraction is limited to the
very small amount of material actually being crushed at any moment ; it is
this point, as much as any other, that tells against the diffusion process, as it
is often impossible to maintain a continuous supply of cane ; in the beet sugar
industry the raw material is stored in silos without deterioration, thus affording
a continuous supply, but such a process is not possible with the cane.

3. Greater elasticity of the milling process. The amount of cane treated
in mills can be varied within wide limits without affecting the efficiency of the
work, and with poor canes the economic limits of exhaustion can be controlled
more reauily than is the case in a diffusion process.

4. Excessive fuel consumption. In Demerara, a consumption of a ton of
coal to a ton of sugar was common with the diffusion process ; when it is
recalled that at the present time there are beet factories working with a coal
consumption of only seven per cent, on the weight of the beets, equal to half a
ton of coal per ton of sugar, it is at once apparent that this enormous
consumption was due, not to faults inherent in the diffusion process, but
rather to the design of particular factories.

In ' Sugar and the Sugar Cane ' (1904) the writer quoted 93'5 per cent,
extraction as the highest figure recorded for mill work with a dilution of
21-65 per cent, on a normal juice. At the present moment (1909) in Hawaii
there are quadruple crushing plants at work, obtaining an extraction averaging
95 per cent, without fuel consumption other than that afforded by the megass.
The best work claimed for diffusion is an extraction of 96 per cent, to 98 per
cent, but in no case is this obtained without a considerable consumption of
extra fuel, and with a dilution higher than that found in milling processes.

Mixed Extraction Processes. — Below are given brief descriptions
of combined milling and diffusion processes that have attracted attention.

235

CANE SUGAR.

Kessler Process. — The fossler* mixed process of extraction works
on somewhat different lines, and has for its object the extraction of sugar from
megass by a continuous process, only one diffuser being used. The apparatus
may be described as an upright U-shaped continuous tube, into which megass
direct from the mill is fed. Falling into this tube the megass is carried for-
ward by a screw conveyer, forced along in a compact mass, and discharged at
the other end of the tube. At one end of the tube, opposite to that at which
the megass enters, water under pressure is pumped in and travels along the

Fio. 138.

tube in a direction opposite to that along which the megass moves, and dis-
charges at the end the megass enters. After the diffused megass has finally
passed through the current of water, it is caught by a screw conveyer which
subjects it to considerable pressure and discharges it from the apparatus. The
megass after leaving the diffuser is crushed in a mill, and the highly diluted
juice thus expressed is returned to the diffuser. This process is illustrated in
Fig. 138.

236

THE DIFFUSION PROCESS.

237

CANE SUGAR.

Perichon Process.5 — This method was originated at the Rodah fac-
tory of the Daira Sanieh in Egypt. The dry crushed megass is received in
trucks in which it is systematically diffused ; the trucks are mounted on
wheels and run on a tram line ; at the hottom of the trucks is a strainer and
discharge valve whereby the liquid contents of a truck can he drawn off, pumped
to an overhead tank, and transferred to the next truck in series. The time
allowed for diffusion in each operation is seven minutes. The weight of cane-
treated in 24 hours was 1000 tons, and the trucks used held about one and
three-quarter tons of megass and were of 90 hectolitres capacity (=316 c.ft);
the megass was diffused in all nine times, the drawn off liquor being about 6°
to 8° Brix in density, and of purity but little less than that of the expressed
juice. After the final washing, the megass is crushed for fuel, the expressed
water containing about fivegrms. sugar per 100 c.c., which would of course be
the loss per 100 cane if the discharged megass weighed the same as the cane.
In Figs. 139 and 1/^0 are given diagrammatic views of the installation.

The Naildet Process. — In the ordinary process of diffusion, that
cell last filled with sliced cane is subjected to the operation known as ' meichage'
i.e., the cell is filled from the bottom upwards with juice from the preceding
cell, and on drawing off the direction of flow is reversed ; in this process the
juice at the bottom is more dilute and is actually the portion that is first drawn
off; in addition, the upper layers of juice having passed over the slices of cane
are colder than the lower layers. The Naudet patents refer to a system of
forced circulation and re-heating, whereby the objections inherent to the usual
process of ' meichage* are overcome, and are expressed in the following words
in the English patents.

11 The application of forced circulation to every succeeding cell of a series
of cells of a diffusion or macerating battery is accomplished by the use of a
pump, the suction side of which communicates with the bottom of the cell
having straining boxes intervening to collect small particles of cush-cush or
megass, that may be retained in the juice, the delivery side of the pump con-
nected to the top of the diffusion vessel having heaters intervening between the
pump and the diffusion vessel to bring the juice to the required temperature."

As applied to the cane sugar industry the process, while including the
system of forced circulation, has come to imply a combination of milling and
diffusion, with simultaneous liming, clarification and filtration.

In the process as erected in quite a number of factories the canes are dry
crushed in a six-roller mill, an extraction of about 70 per cent, of weight of
juice on canes carrying 12 per cent, of fibre being obtained. A cell of the
diffusion battery being filled with the megass resulting from the dry crushing
of the canes, a quantity of juice corresponding to the megass in the cell is
allowed to enter. The cell is then filled with more dilute juice obtained from
the diffusion of a previous lot of megass ; from this cell is taken the charge of
diluted juice that passes on to the boiling house, the circulation of the juice

238

THE DIFFUSION PROCESS.

239

CANE SUGAR.

being conducted in the manner prescribed in the Naudet patent. After the
withdrawal of the charge of juice, the megass remaining in the cell passes
through the usual process of exhaustion in the diffusion battery ; when finally
exhausted it is discharged and passed through a mill for use as fuel.

Comallonga6 gives details of the installation and results obtained at San
Jose in Cuba. The cane worked up was 1 000 tons per 24 hours ; there were
10 diffusers of a capacity of 70 hectolitres (246 cubic feet) each; there were
three cells always out of circuit, filling or emptying, so that the megass went
through a seven-fold diffusion ; per 1 00 kilos of cane, the charge of juice
withdrawn was 92- 93 litres ; the temperature maintained in the battery was
95-100° C.

With canes, containing 13'06per cent, of sugar, the loss in megass was '89
per 100 cane, corresponding to an extraction of 93' 19 per cent.

In the Naudet process, the juice passes directly from the diffusion battery
to the evaporators, the liming being done in the battery, and owing to the
filtration of the juice through the megass, the clarifiers and filter presses are
dispensed with ; notwithstanding this, Comallonga states that, owing to the
extra number of hands required at the battery, the process does not show any
saving in labour.

At the time of writing (1910) the Naudet process not only does not
extend, but some factories that had adopted it have reverted to multiple
milling, and figures supplied to the writer do not show any superiority to those
obtained from an average nine-roller mill.

In justice to this process, it should however be mentioned that the
inventor claims that in at least one case where the process was abandoned
the failure was due to incompetence and to the alteration of his original
designs ; in Madeira, where the process was first applied to the cane, a continued
success is claimed.

GeerligS-Hamakers Process7.— In 1 903, Geerligs and Hamakers
demonstrated by large scale experiments in Java, that by diffusing megass
from a six-roller mill and crusher, an extraction of 98 per cent, vas obtainable
with a dilation of 19*6 per cent, on normal juice. This scheme has not been
adopted, but in the writer's opinion, this process, or one based on similar
grounds, is the only one likely to supersede multiple milling as a means
of sugar extraction from canes.

REFERENCES IN CHAPTER XI I.

1. Spencer's Handbook for Sugar Manufacturers.

2. Overseer's Manual.

3. S. C., 199.

4. /. 8. J., 45.

5. S. (7., 346.

6. Bull, de Soc. Agric,. Cuba, iii. 2.

7. /. S. J., 60.

240

CHAPTER XIII.

THE CLARIFICATION Oil DEFECATION OF THE JUICE.

The object of clarification is to remove from the juice, as far as possible,
all bodies other than sugar, to obtain a juice permitting of easy filtration and
working in the pans and centrifugals, and when making sugars intended for
direct consumption, to obtain a bright, light-coloured, transparent juice.

In rough outline, the processes in use are as below : —

1. The juice is raised to a temperature of about 190° F. to 200° F. by
being passed through a juice heater (see below} ; it is then received into tanks
of 500 gallons' capacity and upwards, where it is allowed to settle for varying
times dependent upon the capacity of the clarifiers in relation to volume of
juice ; after half-an-hour's settling a fairly clear juice can be drawn off above
a deposit of dirt and precipitated matter ; this juice is sufficiently clarified to
be passed direct to the evaporators when dark crystals are being made.

2. The fairly clear juice obtained as in 1 is passed on to vessels known
as eliminators ; these are rectangular tanks of depth from 3 to 3£ feet, and
about 8 feet by 6 feet in length and breadth ; at the bottom is placed a
trunnion pipe into which are fitted brass or copper tubes through which steam
is passed for the purpose of heating the juice. An allowance of 1 square foot
heating surface for every 3 to 4 gallons capacity is usually found. Round
the top edge of the tank is arranged a gutter ; the juice is boiled in these
tanks with the object of bringing the suspended impurities to the surface,
whence they are brushed into the gutter and passed on to the filter presses ;
very clear juices can be obtained by this method, which is however most
wasteful of steam.

3. The juice, either after passing through the juice heater, or when cold,
is received into tanks provided with a heating surface similar to the one
described in 2 ; the heating surface sometimes takes the form of a coil, or
the tank may have a steam jacket. The juice is kept in these tanks at a
temperature of about 205° F. ; at this temperature the heavier particles of dirt
subside, and a lighter aerated scum rises to the surface ; between these layers
is the bulk of the juice, clear and transparent. Many factories in Mauritius
make high-class, white, consumption sugars with these clarifiers alone.

4. Any of the above processes may be used, followed by a bulk filtration
•of the juice.

241

16

CANE SUGAR.

5. In Mauritius a peculiar apparatus known as a Sac Portal (Fig. 11+1)
is frequently used ; this consists of a shallow tank about 1 foot deep, and
about 15 feet in length and breadth; the tank is divided into compartments
about 1 foot wide by divisions parallel to the sides ; at alternate ends of these
divisions the partition is cut away to a depth of 1 inch, and to a length of 1
foot ; juice being admitted to the tank at one corner fills the compartment,
overflows at the far end. changes its direction, fills the next compartment,
again overflows, and so on. The juice has to travel in this way a distance of
about 200 feet, and during all that time it is depositing the suspended dirt. One
apparatus will work continuously for twelve hours, and give a fairly bright
and clear juice, but not comparable with filtered juice.

6. In Australia1 a continuous clarifier is in use. It consists of a cylin-
drical vessel about six feet high, mounted on a conical vessel also about six
feet deep. The clarifier is capable of holding an hour's output of the mills, so
that the dimensions become very large. The juice is introduced by a pipe
which passes over the side of the vessel, and divides at the junction of the
cone and cylinder into eight branches, the juice being projected against the

A n

2

s

5

f — '

7

3

s

f ^

il

\

S

f — '

2

I

1

V

*^

C ^

\

1 c

y

1 ^ ,

A

U

Elevct ft'f>t o/ far f if COTI Flo. ee
FlG. HI.

sides of the cone. As the vessel fills there is a very slow upward movement
of juice, the dirt having time to settle. A gutter runs round the upper edge
of the cylinder, into which the clear juice flows, the dirt depositing on the
sides of the cone. Periodically this dirt is scraped off and the accumulated
deposit discharged without interrupting the working of the apparatus.

7. In San Domingo1 the cold limed juice is introduced at the bottom of a
double-bottomed clarifier. Within the latter is arranged a cylinder reaching
to within six inches of the bottom and to within twelve inches of the clarifier.
The short leg of a syphon reaching nearly to the bottom is placed within the
cylinder and serves to continuously draw off the juice. The juice is kept at a
temperature of 208-210° F., at which temperature the scums rise to the

242

THE CLAKIFICATION OR DEFECATION OF THE JUICE.

surface and are removed without breaking them up. The temperature is
kept constant by an ingenious thermostatic device ; cold water circulates in a
coil of oopper following the curve at the bottom of the clarifier. As this
water is heated it expands, and when the temperature becomes too great the
expansion operates the lever of a throttle valve admitting steam to the double
bottom and shuts off the supply.

8. A type of automatic clarifier due to Hatton2 is shown in Fig. 1J$.
The cold limed juice flows through the pipe a and the regulating valve br
entering the defecator by the pipe c. As the defecator fills up, the juice over-
flows and fills the vessel d, which is closed at the bottom ; hence the juice

U

FIG. 142.

passes upwards through the pipe e and away by the pipe /in to the clear juice
conduit and thence to the evaporators.

The scums collect on the surface of the juice and are removed from time
to time ; it is claimed that these contain so little sugar that filter pressing is
unnecessary. The heat necessary is obtained by passing steam into the double
bottom ; heavier particles which settle are disturbed by occasionally rotating
the scraper and are then stated to be carried upwards to the floating layer of
precipitated material. The amount of steam entering, and consequently the

243

CANE SUGAR.

temperature of the juice is self -con trolled by a thermostat ; at g is shown a
tube filled with water ; the expansion and contraction of the water acts on a
diaphragm in the regulator h and thereby operates the balanced valve at ».

Juice Heater. — A juice heater, Fig. llj.3, consists of a vertical or
horizontal cylindrical cast iron body.

At the upper and lower ends are placed tube plates which cany the tubes
within which the juice circulates, low pressure steam enters at a, the con-
densed water is collected at c, the juice enters at b, and is caused to change its

rr

FIG. 143.

direction twice by the partition plates at e, passing out at /; at d are shown
scum cocks for emptying the vessel after cleaning.

As a rough rule, for every five gallons of juice per hour, one square foot
of heating surface is required.

Instead of heating the juice with back pressure steam from the engines,
juice heaters are sometimes attached as surface condensers to the last body of
the multiple effect evaporator. "Where a good vacuum in the last body is

244

THE CLARIFICATION OR DEFECATION OF THE JUICE.

maintained, the juice may be heated to a maximum temperature of no more
than 130° P., the further rise in temperature required being obtained by a
juice heater as described above.

The method whereby juices are heated with extra steam taken from the
evaporators is described in a subsequent chapter.

Determination of Lime required for Clarification.— The

lime is usually applied as a cream standing about 20°-25° Brix, the quantity
required being determined by one of three methods : —

1. The raw juice is tested in the laboratory, and from the result the
amount of lime required per clarifier is obtained. When working on these
lines frequent tests should be made.

2. To a clarifier half full of juice an amount of lime approximately that
which experience has shown to be necessary is added, and the reaction of the
limed juice to litmus paper observed. According to ;the reaction the same,
more, or less lime is added when the clarifier is full. Working in this way the
proper amount of lime required for a clarifier is soon found.

3. Instead of using litmus paper, the limed juice is filtered into a test
tube, and to the clear filtrate a drop of a solution of lime in sugar is added.
The formation of a precipitate indicates the necessity for more lime, no preci-
pitate occurring with an overlimed or exactly tempered juice.

These three methods do not give consonant results, for a juice limed so
far as to be just alkaline to litmus will give a further precipitation on the
addition of more lime ; precipitation being only complete in the presence of a
considerable excess of lime.

The writer is inclined to regard clarification rather as a craft or art than
as a science, and pays attention to the following points : —

1. Enough lime must be used to give a faint alkaline reaction to litmus.

2. The precipitate must settle readily.

3. No more lime should be used than will satisfy the above requirements.

In the writer's opinion the best control is to place a sample of the juice
from each tank in a four-ounce bottle, and to place each sample on a table con-
\enient for the observation of the employe responsible, who is guided by the
reaction and the colour of the juice and by the setting of the precipitate.

Choice of Lime. — The lime used should be as pure as possible ; the
objectionable constituents that occur in limestones are silica, alumina, magnesia
and sulphate of lime. The first two, if present in limestone, may form a
coating over the lime and prevent it slaking properly. Magnesia and sulphate
of lime are particularly objectionable, as when introduced into the juice they
are deposited, on concentration, on the tubes of the evaporators as scale. Two
per cent, of magnesia should be the highest quantity allowable in a lime
intended for use in a sugar factory.

245

CANE SUGAR.

Below are given analyses of limestones, after Gallois & Dupont3, classed
by them as bad, passable and excellent : —

Material. Bad. Passable. Excellent.

Moisture

.. 4-10

6-25

.. 1-21

Sand, clay, and insoluble matter . .

.'. 4-50

.. 3-17

.. 0-55

Organic matter

"i." 1-20

.. 1-12

. . 0-41

Soluble silica

.. 2-10

... 0-64

. . 0-20

Oxides of iron and alumina

.. 0-37

.. O'lo

.. 0-23

Calcium carbonate (limestone) . .

.. 85-86

.. 87-93

.. 96-58

Magnesium carbonate

. . 0-95

. . 0-53

. . 0-50

Soda and potash

. . 0-05

. .

. .

Undetermined

0-87

0-24

0-32

The Effect of Lime in Clarification. — The effect of lime and
heat on cane juice is

1 . Some proteid and gummy matters are precipitated ; generally speaking
the greater the amount of gums originally present, the greater is the percentage
of gums precipitated.

2. Earthy phosphates and bases of all metals except the alkalies are
precipitated.

3. Mechanical impurities, as wax, fibre, &c., are entangled and caught in
the'proteid and gum precipitate.

4. The juice is made capable of filtration.

5. "With an excess of lime reducing sugars are decomposed into organic
acids; this action is discussed in the following chapter.

6. The purity of the juice is elevated up to a maximum of three to four
units.

The nitrogenous precipitate obtained by the action of lime consists entirely
of albuminoids ; xanthine bases and amides are not precipitated by lime, and
as amides are present chiefly in unripe cane it is in such cane that the nitro-
genous matter chiefly passes on to the after products of the factory. In general,
with lime clarification the writer's opinion is that the best results are obtained
with a juice very slightly alkaline, sensitive litmus paper being used as an
indicator, and, although considerable difference of opinion exists, he does not
place reliance on the value of phenolphthalein as a criterion to show at what
point the addition of lime should cease. It is with juices containing a high
proportion of reducing sugars that an excess of lime is most harmful, and its
evil effects are reflected through the whole course of manufacture, in low
masse cuites hard to purge, in viscous molasses, and in low sugars, dark
coloured and of low test; with juices containing little reducing sugar, an
excess of lime is not detrimental.

246

THE CLARIFICATION OE DEFECATION OF THE JUICE.

Effect of Alkalies on Reducing Sugar.— The action of large
quantities of alkalies on reducing sugars is discussed in the next chapter. As
shown originally by Lobry de Bruyn and van Ekenstein4, reducing sugars,
when heated with small quantities of alkalies, suffer isomeric change ; depen-
dent on the conditions of experiment, dextrose and levulose are mutually
convertible into each other ; in addition, mannose, and a sugar to which the
name glutose5 has been given, are also formed. Mannose is formed in only
small quantity, but the prolonged action of alkalies on the naturally
present reducing sugars of the cane results in the
formation of considerable quantities of glutose ; this
body is unfermentable, its reducing power is half
that of invert sugar, and it may account for the
unfermentable reducing residue found after fer-
menting molasses with yeast. In cane juices the
dextrose is always in excess of the levulose, but
in molasses due to this isomeric change a reversal
of this order may happen.

This isomeric change also takes place under
the influence of the alkali salts of weak acids, such
as sodium acetate.

The Use of Sulphur.— After lime the
agent that has been most used in clarification, and
one the real effect of which is but little known,
is sulphur, in the form of sulphurous acid or
sulphur dioxide. Various apparatus are in use for
impregnating juices with sulphurous acid, of which
three forms are illustrated below.

The ' sulphuring ' is often performed in the
apparatus shown in Fig. Ij^.. It consists in general
of an upright vertical chamber, about twelve feet
high, constructed of wood. At every foot or so
horizontal perforated plates 0, or some other device
calculated to throw the juice into a shower, are
fitted. The sulphur fumes enter the box at the
bottom, being led by the pipe c from the oven where the sulphur is
burnt. The juice enters the sulphur box at the top of b, and falling down
in a fine shower passes out at d. An upward draught is created in the
sulphur box by allowing a jet of steam to exhaust through the pipe «.

In Fig. 145 is given a view of a more detailed scheme ; an air compressor
or pump b forces the air necessary for combustion first through the vessel d,'
packed with quicklime, and thence to the ovens a. The rate at which the
sulphur burns is controlled by the speed of the pump or compressor. Above a

FIG 144.

247

CANE SUGAR.

is a column c, provided with trays packed with chalk, serving to filter the gas
and to retain sulphuric acid. The upper surface of the oven is made double,
so that cold water circulation may cause the condensation of sulphur volatilized.
The sulphur dioxide passes along the pipe /, whence it reaches the bottom of
the sulphitation tanks, being evenly distributed by means of a perforated coil.
The ovens a are provided with doors, through which the sulphur is introduced,
contained in a basket. So as to be continuous in action, the ovens are worked
alternately.

Another method, and one which in the writer's opinion is reliable and
easy of control, is shown in Fig. 1^.6.

The sulphur is burned in the iron pot a, being introduced therein, in
quantities of about one pound at a time, through the aperture J, which may
be kept closed by a tight fitting movable lid. The air necessary for combus-
tion passes through the pipe c, which is filled with lumps of quicklime, which
are renewed daily. The draught and pressure necessary to force the sulphur
gas into the juice are obtained by the injector shown at e, working at not less

FIG. 145.

than 60 Ibs. pressure per square inch ; parts of this exposed to the action of
the gas are made of a lead-antimony alloy containing about five per cent, of
antimony.

The use of sulphur is very old ; it was originally used by Melsens, in 1810,
and there is probably no subject connected with the sugar industry about
which so much has been written, and about which so little is actually known.
What is claimed to occur may be briefly summarized.

1 . Juices are easier to filter.

2. Masse cuites ' work better ' in the pan, and are easier to purge, owing
to a decrease in viscosity.

3. A greater precipitation of impurities occurs.

4. Juices are bleached.

In so far as regards the bleaching action of sulphurous acid, it may be
remarked that any acid gives a light coloured juice ; Maxwell6, however, has
shown that sugar solutions coloured artificially by prolonged heating with acids
are completely decolourized by sulphurous acid.

248

THE CLARIFICATION OR DEFECATION OF THE JUICE.

In experiments made by the writer limed juices and limed and sulphured
juices exactly duplicating factory conditions gave the same weight of precipi-
tate, and the writer does not believe that it can be claimed that sulphuring
gives an increase to the purity of the juice above that due to the juice of lime.
Yery different methods of sulphuring juices are in vogue ; in Louisiana it is
usual to sulphur the cold juice until the acidity is from 3 c.c. to 5 c.c.
N/10 acid per 10 c.c. of juice; lime is then added until the juice is very
slightly acid. In Java, according to Prinsen Geerligs, the raw juice is limed
with about twice as much lime as is indicated as necessary by the saccharate of
lime test (supra) ; afterwards the juice is sulphured until only a faint red
colouration is afforded by phenolpthalein. In Mauritius, where white sugars
are made, it is general to sulphur first and lime afterwards, but in Demerara, in
the manufacture of Demerara crystals, the juice is generally limed before
sulphuring.

ir

FIG. 146.

In the writer's opinion it is not of much moment whether lime or sulphur
be used first, as long as the following points are observed : —

1. Heat should not be applied to a juice in the presence of a notable
excess of either reagent.

2. The result of the combined treatment should be to obtain a juice
almost exactly neutral.

In burning sulphur it is of great importance that the air be dry, else a part
of the sulphur burns to sulphuric acid, which not only is of no use but is a
cause of the deposit of scale and of the corrosion of the valve seatings in the
vacuum pumps.

Two classes of sulphites exist, both of which may be present in limed
and sulphured juice : the normal neutral, sulphites of the formula M2S03

249

CANE SUGAR.

and the acid bisulphites of the formula MHS03. These two forms react
differently with litmus and phenolphthalein, the most generally used indicators
in the sugar house. Soluble sulphites react neutral with phenolphthalein, but
alkaline with litmus ; hence when a sulphured juice reacts neutral to phenol-
phthalein the normal sulphite is present, and such a juice may give an alkaline
reaction with litmus ; when a juice reacts acid with litmus, then bisulphites
are present. A distinction beween the two classes of sulphites is that the
normal calcium sulphite is insoluble, the bisulphite being soluble ; if, then, a
juice is sulphured in such a way that bisulphites are present, these remain in
solution ; in the evaporator they become decomposed into S02 and the normal
sulphite ; the former on oxidation accounts for the presence of sulphuric acid
in calandria water, and the latter also oxidizing appears as a scale of calcium
sulphate on the tubes of the evaporators.

Use of Phosphoric Acid. — A third agent employed as a clarificant
in more or less general use is phosphoric acid appearing under various trade
names as ' Clariphos,' * Ehrmanite.' It is used to counteract the effects of an
over application of lime, and also as an actual precipitant of non-sugar. If a
solution of phosphoric acid be added to a limed juice, the first effect is to pro-
duce a precipitate of calcium phosphate ; if this precipitate be collected it
will be found to contain a notable percentage of organic matter ; if, however,
the addition of phosphoric acid be continued, a soluble superphosphate of lime
is formed, and the original precipitate redissolves.

Oxalic Acid. — This body has also been, and sometimes is, used in a
similar way, and the precipitate of calcium oxalate, which does not redissolve
on adding an excess of oxalic acid, also contains a notable quantity of organic
matter.

Carbonate of Soda.— An excess of lime salts has the property of
making the molasses very viscid, and in some factories it is the practice to
clarify with lime and soda, using the latter to neutralize the natural acidity of
the juice, and the lime to effect precipitation of the albumenoids.

Other Agents Proposed for Clarification. — Upwards of six
hundred agents and combinations of agents have been proposed for use in
clarification ; they fall into two main classes, those that aim at a discoloration
of the juices and those that are intended to remove non-sugars from the juices.
The removal of non-sugars is often attempted by the precipitation within the
solution of a bulky precipitate, such as of alumina, phosphate of lime. The
proposed agents may be classified thus : —

1. Sulphur compounds, including sulphurous acid, soluble sulphites and
bisulphites, including those of the alkalies, alkaline earths, aluminium andiron,
hydrosulphites of soda and of lime.

250

THE CLARIFICATION OR DEFECATION OF THE JUICE.

, 2. Phosphoric acid and soluble phosphates and acid phosphates of the
alkalies and alkaline earths and of aluminium.

3. Salts of aluminium in combination with bodies designed to produce a
precipitate of alumina, and including the aluminates of the alkalies and of the
alkaline earths ; the precipitation of alumina within a sugar solution whether
from an alum or aluminate produces a notable clearing of the solution and the
carrying down of much colloid matter, but the writer is of the opinion that
the value of the amount of material required is greater than the benefit to be
obtained, in addition to the difficulty of handling the very bulky gelatinous
precipitate formed.

4. Salts of the heavy metals, especially of lead, zinc and tin. All of
these produce copious precipitates, but their poisonous nature is an insuperable
obstacle to their use.

5. Baryta and its salts, and in combination with other agents. Baryta is
certainly a powerful clarifying agent, but its poisonous nature, as well as the
expense involved, prevents its use.

6. Agents designed to the removal of potash, including the use of
fluosilicic acid and its salts, and filtration through layers of calcium aluminium
silicates.

7. Unclassified agents, including ozone, chlorine,, hypochlorous acid,
hydrofluoric acid, permanganate of potash, chromic acid, tannic acid often
suggested to be used in combination with aluminum salts, oxalic acid in com-
bination with lime, clay, brick dust, oils, kieselguhr, albumen.

8. Electrical processes.

Of later processes that have been proposed may be cited those of Hanson7,
which include the use of zinc, tin, hydrosulphurous acid, hydrogen peroxide,
and aims at a decoloration of the juice and direct manufacture of white sugar
by alternate oxidations and reductions. Gans8 proposes the use of artificial
zeolites or calcium aluminium silicates as a filtering material, whereby the
potash of the juices is replaced by lime ; this material was placed on the
market under the name of ' Permutit,' but Claassen9, who examined its action,
found that, although the potash could be thus removed, the viscosity of the
resulting material due to the substituted lime salts was much increased, and
he was unable to recommend its use. Hlavati10 proposes the removal of
potash by means of fluosilicic acid, and Besson11 employs powdered aluminium
alloys in an alkaline juice to obtain a precipitation of alumina and decoloration
through the agency of the hydrogen evolved. When this plan is used in the
juice in the evaporation, a diminution of the deposit of scale and an increased
transmission of heat is claimed.

A detailed list of the various proposals has been given by von
Lippmann12.

251

CANE SUGAR.

Clarification for White and Yellow Sugars.— The clarifi-
cation of juices for the manufacture of these sugars differs from that used
when making refining crystals in that the action of sulphurous acid is essential,
and that juices are boiled with a slight acid reaction ; in addition much greater
care is taken to remove suspended and floating foreign matter from the juices.

In Demerara the process followed is as under :

The raw juice is limed cold and sulphured generally in a * sulphur
tower,' Fig. 144> the appearance of the juice — very pale yellow — forming a
guide to the operator of the efficacy of the treatment ; the juice now has an
acidity of about 5 c.c. - 7 c.c. N/10 acid per 100 c.c. of juice, phenolphthalein
being used as indicator. After passing through a heater and settling, the
partially clarified juice is run into vessels of about 1000 gallons gross capacity
in which are arranged steam coils ; around the edge of these vessels is
arranged a gutter. These vessels are known as eliminators ; the juice is made
to boil, and the scum that rises to the surface is brushed off with wooden tools
into the gutter; to the juice in the eliminators phosphoric acid is added, the
acidity now lying from 12 c.c. - 20 c.c. N/10 acid per 100 c.c. of juice. This
method of cleaning juices is most thermophagous, and at best much inferior
to the effect obtained by the use of mechanical or sand filters ; results quite
equal to those obtained by eliminators may be obtained by straining the juice
through fine copper gauze of 120 meshes per linear inch. In the manufacture
of white sugars in Mauritius a similar process is followed, except that the
acidity of the finally tempered juice is considerably less, and is about 8-12
c.c. N/10 acid per 100 c.c. of juice.

In the writer's opinion the manufacture of fancy sugars is largely a
question of the acidity of juice in connection with the colour reactions of cane
juice, which, having an important bearing on the matter, may be mentioned
here.

Use of Hydrosulphite. — About 1904 the manufacture of staple
hydrosulphites became possible, and they were introduced into the dye indus-
try, and thence, as decolorizing agents, into the sugar industry. The sodium
salt appears under the trade name of ' Blankit,' and the calcium salt under
that of 'Redos.'

Hydrosulphites are very powerful reducing ageuts, and act under the
equation

Na2S204 + 0+ H20 = 2NaHS03.

In the cane sugar industry they find an application in the bleaching of
juices and syrups in the manufacture of direct consumption sugars.

In connection with their use it has been observed that after juices and
syrups have been bleached they become darkened on exposure, and it is usual
to introduce the hydrosulphite dry into the vacuum pan. A quantity of

252

THE CLARIFICATION OR DEFECATION OF THE JUICE.

hydrosulphite required to obtain the maximum bleaching effect found by the
writer was one pound per ton of sugar, but the quantity necessary has to be
determined by trial and error, and a much less quantity is stated to be required
by the makers of this compound.

Hydrosulphite has no effect on the dark coloured products obtained on
overheating sugar juices, and the specific effect claimed for it in reducing
viscosity hardly seems possible when the small quantity used is borne
in mind.

The Colour Reactions of Cane Juice.— The colour reactions
of cane juice having an important bearing on the manufacture of direct con-
sumption sugar may be mentioned here. In the presence of an excess of
alkali, filtered cane juice is of a golden yellow colour; if the alkali be
gradually neutralized with an acid a point is reached where the golden yellow
colour turns to an olive brown; the addition of the acid being continued, the
cane juice finally becomes almost colourless. When in the intermediate olive
brown zone, the juice is almost exactly neutral. The colour reactions of cane
juice as described above are exemplified in the following experiment : —

To 100 c.c. of clarified almost neutral cane juice, exactly sufficient normal
caustic soda was added to develop the golden yellow tint, the quantity found
necessary to be added being 1 c.c. To 1 00 c.c. of the cane juice thus treated
normal sulphuric acid was added and the changes in colour observed ; the
different juices were kept at a temperature of 95° C. for half-an-hour, so as to
determine at what point appreciable inversion (see below) set in. The details
of an experiment are given below.

100 c.c. of clarified cane juice treated with 1 c.c. normal caustic soda
developed maximum yellow colouration.

c.c. normal acid Polarization after

added per 100 c.c. Colour. Reaction. heating to 95° C,

of prepared juice. for half-an-hour.

•0 Golden Yellow Alkaline 58-1

•4 ... „ .... „ .... 58-0

•8 .... „ „ .... 58-1

•9 j ... ( Intermediate Neutral 58 '0

1-2 J .... I Olive brown zone ... ,, 58*0

1-4 .... Light .... Acid 58'1

2-0 .... ,, ..... ,, 58-0

2-2 „ .... ,, 57-0

2-6 .... „ .... „ .... 49-0

It was not until there was an excess of normal sulphuric acid of 1 c.c.
per 100 c.c. of juice over and above the neutral intermediate zone that
inversion was detected.

In Sugar and the Sugar Cane the author expressed himself thus : " This
is thus the limit which the manufacturer can allow himself when making

253

CANE SUGAK.

consumption sugars without danger of inversion." This reasoning was, however,
incorrect, for the invertive action is profoundly modified by the large amount
of neutral salt present in the experiment and which does not occur in the
boiling-house ; also the acids used in the boiling-house — sulphurous and
phosphoric — have in any case a much less pronounced action than sulphuric.
Actually, however, juices with an acidity due to phosphoric acid equal to a
maximum of 20 c.c. decinormal acid per 100 c.c. of juice are worked in the
manufacture of consumption sugars.

Indicators. — By an indicator is meant a body which by a change of
colour indicates the end point of some chemical reaction, and in the sugar
house it is used to indicate the acidity or alkalinity of the juice. The two
indicators most extensively employed are litmus and phenolphthalein ; the
former is red in acid and blue in alkaline solution ; the latter, colourless and
crimson. A difference in the indication of these bodies with lime and in the
presence of sulphites has already been noted, and the question, which is the
most reliable indicator to use, is one which is constantly recurring. This is
really largely a question of the glucose content of the juice; phenolphthalein
does not give an alkaline reaction until there is present considerably more lime
than is required to give an alkaline reaction with litmus; if juices such as are
common in Demerara, containing from 1*5 per cent, to 2 per cent, of glucose
were limed till they gave an alkaline reaction with phenolphthalein, serious
trouble, due to the action of the lime on the glucose, would result ; juices
with less glucose will be able to take a larger amount of lime and obtain a
greater precipitation of non-sugar without injury.

In saturating alkaline juices with sulphurous acid it must be remembered
that litmus reacts alkaline to acid sulphites and hence phenolphthalein is the
more suitable indicator.

Phenolphthalein is exclusively used in the beet sugar industry, but con-
ditions are dissimilar and Pellet in particular has frequently insisted that
litmus is the most general cane sugar indicator.

An indicator of some little use is a reagent consisting of equal parts of
methyl orange and rosolic acid in alcoholic solution ; this reagent becomes a
peculiar port- wine red in the presence of bisulphites, but in general the colour
of cane products is so pronounced as to mask the appearance of this colour.
The colouring matter of cane juice itself forms an indicator of no inconsiderable
value, and is discussed above.

Speaking generally, the appearance of the juice viewed in a tall glass
makes a valuable criterion, a clear hock-coloured juice with a rapidly
settling precipitate being the appearance to be looked for; the condition of the
press cake is also a guide, soft sloppy cakes being often the result of too little
lime.

254

THE CLAKIFICATION OR DEFECATION OF THE JUICE.

Inversion. — Cane sugar, under the influence of acids, is quantitatively
converted into dextrose and levulose under the equation

CxaH^O^+H^CeH^Oe + CeH^Qe
Cane Sugar Water Dextrose Levulose

Under the ionic hypothesis an acid in solution is conceived as being in
part dissociated into hydrogen ions and into acid-radical ions ; thus hydrochloric
acid in solution is taken as consisting of undissociated HC1, and of H ions, and
of Cl ions, the former carrying a -j- and the latter a — charge of electricity.
The inversion of cane sugar under the same hypothesis, and, indeed, all the
particular properties of an acid, are held to he due to the hydrogen ions. A
strong acid is one which is largely, and a weak acid is one which is slightly,
dissociated. The chief laws under which the inversion of cane sugar proceeds
are summarized below.

1. Rate of Inversion. — "When all other conditions are unchanged, the
rate of inversion is proportional to the active mass, i.e., when the temperature
and the concentration of the acid are unchanged, a 20 per cent, solution of
cane sugar inverts twice as fast as a 10 per cent, solution. Developed
mathematically, this statement becomes reduced to the following form : —

In a sugar solution let there be a parts of sugar present ; in a small interval
of time, t, let x parts be inverted. There are now present a — x parts of cane
sugar. Since the rate of change is proportional to the active mass,

d x

—— = k (a — x) where 1c is a constant.

d t

"Whence, by integration log. = k t

d — x

I a

-J los- j-n = k

The constant k gives a means of comparing the strength of different
acids, or, under the ionic hypothesis, the degree of dissociation. This law was
found experimentally by "Wilhelmy in 1350, and developed on a priori reasoning
by Guldberg and Waage in 1867. It forms a typical instance of the
universal law that rate of chemical change is proportional to the active mass.

As definitely applied to a sugar solution in acid medium, let the total
change in polarization due to inversion be- a; then a is proportional to the
amount of sugar originally present. Let the fall in polarization, i.e., the
algebraical difference between the initial reading and the reading after any
time interval, t, be x ; then x is proportional to the amount of sugar inverted.
The calculation of the constant will then appear as in the following example.

Initial reading, 40°; reading after complete inversion, — 12°; total
change = # = 52°; reading after 60 minutes, 30°; proportionate amount of
sugar inverted = # = 40 — 30 = 10. Then

| •"• • • Constant = ^-log. ^-Q = -001546. .

255

CANE SUGAR.

2. Influence of Acid. — The constant k was determined by Ostwald13 in
1884, for a large number of acids; some values as found by him are given
below. These are referred to half normal strength, to 25° C. temperature, the
time being expressed in minutes, and the logarithms being common ones.

Acid. Constant. | Acid. Constant.

Hydrobromic -002187 Sulphurous . ..... '0006630

Hydrochloric -002438 Oxalic -0004000

Nitric -002187 Phosphoric -0001357

Sulphuric -001172 Acetic -0000088

3. Effect of Concentration of Acid. — Within comparatively narrow limits
the rate of inversion is nearly directly proportional to the concentration of the
acid. With the stronger acids, however, the rate of inversion decreases more
rapidly than does the decrease in concentration ; with weaker acids, the reverse
holds.

4. Effect of Temperature. — The following empirical equation, due to
Urech,14 connects velocity of inversion and temperature: —

A CTt T0)

C1 = Ci)-e TO I*

where C0 and Cl are the rates of inversion at T0 and Tlt e is the base of
the natural system of logarithms, and A is a constant, and equal to 12820.
Putting the rate of inversion at 25° C. = l, this expression gives the
following rates of inversion at the stated temperatures : —

°c.

Rate.

°c.

Rate.

°c.

Rate.

25 ....

1

60

... 91-8

85

. . . 1354

40 ....

7-6

65 .

. . 162

90

... 2110

45 ....

14-3

70

... 282

95

. . . 3573

50 ....

26-7

75

... 483

100

. . 5659

55

57-7

80

814

The Effect of Neutral Salts. — It was originally shown by Arrhenius15
that the rate of inversion by acids was accelerated by the presence of the
halides and nitrates of the alkalies and alkaline earths. The writer16 has
extended his observations, and has found : —

1. In concentration up to '02 N at 100° C., the halides and nitrates
have an inappreciable effect on the rate of inversion with very dilute acids.

2. Under similar conditions the sulphates, sulphites, oxalates, and all
^alkali and alkaline earth salts of weaker acids retard inversion.

3. In concentration of acid and salt of the normal order, at ordinary
temperatures, the halides and nitrates of the alkalies and alkaline earths
.accelerate the rate of inversion ; the acceleration increases progressively from
chloride to bromide, to iodide, the effect of nitrates being similar to that of
chlorides. A difference in the base of the salt has very little, if any, effect ;
thus, the acceleration due to sodium chloride is substantially the same as that
-due to calcium chloride.

256

FIG. 17.
PORT

• MACKAY.

PLATE XVI

THE CLARIFICATION OR DEFECATION OF THE JUICE.

4. Under similar conditions, sulphates, sulphites, oxalates, &c., retard
the rate of inversion.

Effect of Glucose. — The action of glucose on the inversion of cane sugar
is a peculiar subject, some investigators finding that glucose of itself caused
inversion, and others observing no effect. Geerligs17, in investigating the
subject, came to the conclusion that glucose of itself had no invertive action,
but that in the presence of neutral salts, such as chlorides, nitrates and
sulphates of the alkalies and alkaline earths, inversion occurred at the
temperature of boiling water, owing to a slight hydrolysis of the neutral salt
under the influence of the glucose. The writer16 in investigating the same
subject failed to obtain any trace of inversion due to the combined influence
of glucose and neutral salts, when the latter were present in normal
concentration.*

Inversion under Acid Salts. — Salts of the heavy metals, such as zinc
sulphate, also cause the inversion of cane sugar. This has been chiefly studied
by Long18; the inversion is ascribed to the partial hydrolysis of the salt,
thereby affording free hydrogen ions in solution.

Inversion under the Influence of Enzymes. — Besides chemical inversion under
the influence of acids and acids salts, cane sugar is inverted by the action of
certain ferments known collectively as enzymes. The enzyme most studied
is that secreted by yeast, and known as invertase. The properties of this body
were first investigated by 0' Sullivan and Thompson19, who found that the most
favourable concentration of the sugar solution was 20 per cent., that the optimum
temperature was 55° C. to 60° C., the enzyme being slowly destroyed at 65° C.,
and instantaneously at 75° C. The action of invertase is greatly accelerated by
minute traces of acids. 0' Sullivan and Thompson found that the law of mass
action held for the action of invertase, a result not obtained by subsequent
workers until C. S. Hudson21 showed that these had neglected to take into
account the mutarotation of the invert sugar formed.

Another instance of enzyme inversion of interest to the sugar industry
was examined by Lewton-Brain22 ; he found that the fungus connected with
the Red Rot of the Stem (Colletotrichum fakatum) secreted an invertase
capable of rapid inversion of cane sugar.

Inversion and Manufacture of Consumption Sugars. —

It has already been stated that in the manufacture of consumption sugars it is
customary to work juices with an acidity reaching up to 20 c.c. decinormal
acid per 100 c.c. of juice. Sugar and water, even with acetic acid, at such
an acidity, would be very rapidly inverted at 100°C. In the sugar house,
however, the system consists of sugar, water, acid and neutral salt ; the action
of the neutral salt decreases (under the ionic hypothesis) the concentration

* Since the above was in type, Mr. Geerligs has suggested that the discrepancy in
the results was due to the fact that neutral inorganic salts only invert sucrose in the
1 resence of glucose in the case where they occur in feeble concentration. Highly con-
centrated salt solutions are without invertive action.

257

17

CANE SUGAR.

of the hydrogen ions, and it is for this reason that it is possible to work juices
with so high an acidity ; the greater the amount of neutral salt the higher
can he the acidity. A heavily limed juice, with the lime 'cut ouf by excessive
sulphuring will contain a large amount of neutral salt, and can be worked
with a higher acidity than one not so heavily limed. This point is empirically
known to many West Indian sugar boilers.

Th.e Demiiig1 Process. — This process which was introduced a
number of years ago has undergone numerous modifications from time to time,
and at the present time is worked under more than one combination. Included
in the scheme are two distinct ideas, the raising of the juice to a temperature
of about 230° F. under pressure (superheat clarification) and the use of a
specially designed form of a continuous settler. The different parts of the
apparatus are described below.

FIG. 147.

The Digester. — The digester, aa Fig. 147, is a combination of return
current tubular horizontal heaters of conventional pattern ; they are worked
in pairs or in sets of three ; exhaust steam is employed as a heating agent in
that heater through which the juice first passes, and live steam in the later ones.

The Alsorler. — The absorber is a combined cooler and heater ; in the
earlier plants this consisted of a tubular element, in the interior of the
tubes of which the superheated juices from the digester circulated ; on the
outside of the tubes cold juice on its way to the digester passed; an inter-
change of heat occurred, and juice at a temperature of about 200° F. was
delivered to the settling tanks. The absorber shown at W, Fig. 1^7, is the
most recent form. It consists of a closed outer vessel wherein is maintained a

258

THE CLARIFICATION OR DEFECATION OF THE JUICE.

vacuum of about six inches ; the superheated juice from the digesters is dis-
chai ged into this vessel ; in the upper part of the absorber is a tubular element
cc within the tubes of which the cold juice circulates; the superheated juices
on entering the absorber at once boil under the reduced pressure, and the
vapours given off condense on the tubular element, at the same time raising
the temperature of the cold juice therein contained.

The Settling Tank. — The continuous settling tank is shown at dd\ it
consists of a cylindrical portion mounted on a funnel-shaped lower part.
Inside is arranged a truncated cone of sheet iron. The juice enters through
four pipes and follows the course indicated by the arrows, depositing its
suspended matter on the sides of the tank, and on the cone ; on leaving the
tank the juice passes direct to the evaporators. Periodically the deposit of
dirt is discharged through the pipe at the bottom of the tank and sent to the
presses. The settler shown in Fig. l/tf is closed ; in the earlier plants open
settlers were used, and these tanks were often arranged in series, the juice
from the first tank dividing into two currents, so that the velocity of flow was
halved, and an opportunity given for a thorough deposit of the dirt.

The Deming plant is sent out equipped with carefully thought out
arrangements for the control of liming and sulphuring and of the temperatures-
in the various parts of the plant. So as not to cause confusion these arrange-
ments are not shown in the drawing, which is confined to the essential parts of
the apparatus.

Mechanically, and from the point of view of steam economy, there is no
doubt that this process is very efficient, but from the chemical standpoint it
has been subjected to very severe criticism; any slight error in controlling the
amount of lime or sulphur gas added will, at the high temperature which forms
a part of the process, result in a serious loss of sugar ; and in a number of
instances where the plant has been installed the superheat part of the scheme
has been dropped, the mechanical ideas being retained.

The following figures dealing with the process are due to Beeson22 : —

Juice. s™al sucrose. S°s1jJaiI?ot Purity. Glucose.

Diffusion 14-9 .. 11-22 .. 1-69 .. 75-3 .. 1-99

Ordinary Clarification 14'9 . . 12-04 . 0*83 . . 80'9 . . 2-03

Deming Clarification .. 14'9 .. 11-58 .. 1-29 .. 77'7 .. 2-03

Diffusion 14-9 11-78 . . 1-11 . . 79-1 . . 2-01

Ordinary Clarification 14'9 .. 11-65 .. 1-21 .. 78'2 .. 2'04

Deming Clarification . 14'9 .. 10'85 .. 2'06 .. 72-8 .. 1-99

Tnspo Glucose Total Albumen- 4™i/ioa Alcoholic

ratio. Proteids. oids. Amides. Precipitate.

Diffusion 17'7 . . -248 . . -0617 . . -1863 . . -105

Ordinary Clarification. 16'9 . . -205 . . '0416 . . '1634 . . -202

Deming Clarification .. 17'5 .. -208 .. -0434 .. -1646 .. '171

Diffusion 17-1 . . -215 . . -0733 . . -1417 . . -246

Ordinary Clarification. 17'5 . . -201 . . -0538 . . '1472 . . -336

Deming Clarification . . 18-3 . . -202 . . -0447 . . '1574 . . -297

259

CANE SUGAR.

Edson23 experimenting at Calument, Louisiana, found juices treated by
the Deming process to filter more rapidly than others.

Temperature of Clarification.
215° F. 230° F. 246° F. 260° F.

Filtration started at . . 3 '45 . . 3 '45 . . 3-45 . . 3 45
Juice freed from mud at 4-15 . . 4'05 . . 3-56 . . 3-56
Time of filtration . . . . 30 min. . . 20 min. . . 11 min. . . 11 min.

Using juice heated to )

260° F. as a unit, the 2'75 .. 1-82 .. I'OO .. 1-00
time of filtration was )

The process was also subjected to a trial by Geerligs24, in Java, the
factory in question working alternately the Deming and the older process.
The analyses of the juice show no difference, but the analyses of the molasses
indicate that more gums were precipitated by the Deming process.

Ash. Lime. Gum. Silica.

Molasses, Cheribon cane, Defecation 4-67 .,. 0-207 .. 0-808 .. 1-28

,, ,, Deming.. 4-59 ..0'245 ,.' 0-720 .. 1'09

,, Muntok ,, Defecation 4'50 .. 0'370 .. 0-636 .. 1'32

,, Deming.. 4-55 .. 0'331 .. 0'604 .. 1-24

Geerligs remarks that "from a chemical point of view Deming' s superheat
clarification stands in no respect behind the usual defecation process, whilst its
mechanical advantages are many."

Increase in Purity. — The increase in purity due to the action of
lime varies with the nature of the bodies in the juice ; thus with unripe cane
much of the nitrogen is present as amide and is not precipitated, whereas in
mature cane the nitrogen appears chiefly as albumenoids and is precipitated.
Similarly a greater or less quantity of phosphates in the juice will affect the
increase in purity ; the figures from the Mutual Control of Java Factories show
an increase of from 1*5 to 1 '9 units where the purity is about 85 ; a similar
increase is usual with the purer juices of the Hawaiian Islands and the figures
given by Browne25 as typical of Louisiana indicate a similar increase. In
addition to the increase in purity due to the action of lime and heat, a further
increase follows due to the precipitation of bodies as scale on evaporation ; this
increase may amount to as much as a unit between the clarified juice and the
syrup.

Abnormal Purities. — Geerligs26 in particular has described instances
of juices showing a very high purity which fell to normal figures in the syrup ;
he failed to obtain indications of any bodies precipitable by lime to which
the phenomenon could be ascribed and was inclined to think it due to presence
of alcohol formed in fungus-attacked canes. Pellet27, however, thinks
imprisoned air a more likely cause ; either of these bodies would give a
fictitiously low degree of Brix and would disappear in the evaporation.

260

THE CLARIFICATION OR DEFECATION OF THE JUICE.

REFERENCES IN CHAPTER XIIE.

1. Ency. Brit. X. Edit. Art. Sugar.

2. /. 8. J., 88.

3. After Spencer's Handbook for Beet Sugar Manufacturers.

4. Arch., 1896, 224.

5. Bull. Assoc., 15, 163.

6. Louisiana Bulletin, 2, 38, 1407.

7. English Patents, 11790 and 19815 of 1896 and 25642 of 1898.

8. German Patent, 174097 of 1905 ; English Patent, 8232 of 1907.

9. I. S. J., 107 and 108.

10. English Patent, 15274 of 1903.

11. Bull. Assoc., 20, 131.

12. Deut. Zuck. Ind., 1909, 9.

13. Jour. Prak. Chem., 30, 95.

14. Ber. Deut. Chem. Oesel., 16, 765; 17, 2175.

15. Zeit. Phys. Chem., 4, 226.

16. Bull. 35, Agric. H.S.P.A.

17. 8. C., 313.

18. Jour. Am. Chem. Soc., 18, 693.

19. Jour. Chem. Soc., 57, 834.

20. Jour. Am. Chem. Soc., 30, 1564.

21. Ball. 9, Path. H.S.P.A.

22. S. C., 330.

23. 8. C., 345.

24. I. S. J., 19.

25. /. S. J., 91.

26. /. S. J., 111.

27. /. S. J., 119.

261

CHAPTER XIY.

THE CARBONATION* PROCESS.

The carbonation process, which is quite generally adopted in beet sugar
factories, has only been applied to the manufacture of cane sugar in a few
instances in Java and India. This process, though very successful in beet
factories, gave bad results when first introduced into cane sugar factories
owing to the presence of glucose in cane juice, — this body not being a
constituent of sound beets. It is owing to the efforts of Geerligs and Winter
in Java that the process has been made even practicable, but that it will ever
be generally adopted is problematical.

The essential principle of the process is the use of a large quantity of
lime in the clarification, giving a very copious precipitate of organic non-sugar,
the excess of lime being removed by the passage of carbon dioxide as an
insoluble carbonate. Besides precipitating organic matter, the lime acts on the
glucose, converting it into saccharic, glucinic, and lactic acids, the proportions
of each being dependent on the temperature at which reaction takes place.

Single Carbonation. — In the single process a quantity of lime
which, calculated as dry anhydrous lime, amounts to as much as 1 to I'd
per cent, of the weight of the cane is added to the juice ; carbon dioxide
generated by the combustion of limestone in limekilns is pumped through the
juice until the latter is neutral; the juice is all this time at a temperature not
•exceeding 55° C. ; the temperature is now raised to 90° C., and the juice
filtered ; in some cases the juice is filtered en masse, and in others it is allowed
to settle and only the scums filtered.

Double Carbonation. — In the double carbonation process the juice
is limed as above at a temperature not exceeding 55° C., and carbon dioxide
passed in until the alkalinity is one represented by -05 per cent, lime ; the
juice is then separated from the precipitate by means of filtration, raised to
the boiling point, saturated with carbon dioxide, boiled for a few minutes to
break up bicarbonates, and again filtered.

The point at which the passage of carbonic acid gas is stopped is indicated
by a clear, bright coloured juice with a rapidly settling precipitate.

*I write 'carbonation' in preference to ' carboxatation,' as being etymologically the correct
iorm, although the latter spelling is adopted by Geerligs and by Ware.— (W. D.)

262

THE CARBONATION PROCESS.

Chemistry of the Process. — The chemistry of the process is thus
explained by Geerligs1. At temperatures near the boiling point the action of
lime on glucose is to form chiefly saccharic and glucinic acids : if the tem-
perature, however, does not rise above 60° C., saccharic and lactic acids are
chiefly formed, and only small quantities of glucinic acid. The glucinic acid
formed combines with the lime to produce an insoluble basic glucinate ; this
basic glucinate is insoluble in an alkaline medium at temperatures below 60° C.,
but redissolves with rise of temperature or on neutralization of the free alkali.
In the single process, then, the glucinate of lime, after being insoluble, again
becomes soluble, and re-enters into solution ; in the double process it is
removed.

In addition to the action of an excess of lime on glucose, gummy and
other matters are only precipitated by an excess of lime and considerably more
impurities are thrown down by the excess of lime than in the ordinary process ;
on neutralization these bodies redissolve, and the final effect is the same as if
lime had only been added in the usual quantities. This effect takes place in
the single process, and it is only by filtering the strongly alkaline solution, and
by removing the lime afterwards that the full benefit of the carbonation pro-
cess is obtained.

Below are given details of analyses (by Geerligs) of juices treated by the
carbonation process ; analyses of the scums are given in the succeeding chapter.

Sugar, Glucose, Pectine,

Per Per Glucose Per

Brix. cent. cent. Purity, ratio. cent.

Mill juice 18.4 .. 15-72 .. 0'92 .. 85-6 .. 5'9 .. 0'634

Clarified by defecation 18-6 . . 15'99 . . 0'95 . . 86-1 . . 5-9 . . 0-292
Clarified by carbonation 16'9 . . 14-65 . . 0-44 . . 86'7 . . 3*0 . . 0-142

Use of Carbonation Process. — The double carbonation process
is used in a few factories in Java, and perhaps in one or two elsewhere. By
its use a white sugar intended for direct consumption is obtained with less
trouble than can be obtained by any other process ; in this regard, however,
the writer would remark that the best white sugars of Mauritius made by a
defecation process combined with the use of sulphur and phosphoric acid are
equal to any that he has seen prepared by the carbonation process.

The single carbonation process appears to be adapted to factories which
obtain a gummy juice, and is not adapted for making white sugars.

Effect on Manufacture. — The decomposition of the glucose by
lime gives rise to organic acids and hence carbonated juices contain more salts
than do defecated juices. In discussing this point, Geerligs2 in 1895 seems
to imply that carbonation molasses contain more sucrose per unit of water
than do defecation molasses; this distinction he correlates with his Theory
of Molasses (cf. Chap. XIX.) ; ou the other hand he points out that owing to

263

CAKE SUGAR.

the decreased quantity of non-sugar the actual loss of sugar is not increased ;
in addition carbonation molasses are less viscous and lighter coloured, so that
they are more easily removed in the centrifugals.

Later analyses of carbonation molasses published by Geerligs in " Cane
Sugar and its Manufacture " do not show a higher purity than do defecation
molasses; the average of eight carbonation factories and of sixty-seven
defecation factories are as under: —

Total

Solids Polari- Sucrose Apparent True

Brix. Percent, zation. Percent. Purity. Purity. Glucose. Gums. Lime
Garb... 83-7 .. 78'6 .. 31-1 .. 31'3 .. 37'1 .. 39-8 .. 21-6 .. -74 .. 1-38
Def. .. 85-4 .. 80-0 .. 28-8 .. 33'9 .. 33'7 .. 42'4 . 23'6 .. 1-95 .. '53

It will be observed however that the difference between the polarization
and sucrose per cent, is much less in the carbonation molasses, than in the
defecation molasses ; this is of course to be correlated with Lobry-de-Bruyn's
and Yan Ekenstein's observations on the transformations of reducing sugars in
the presence of alkalies.

Finally, Hazewinkel3 in obtaining a formula for available sugar allows a
loss of 5 per cent, of sucrose in the carbonation process ; this would seem to
imply that the recovery of sucrose in this process is less than in the defecation
process, and is to be ascribed to the action of the lime in large quantity on the
sucrose.

Details Of Routine. — It remains to describe the practice of the pro-
cess, which may be varied in details to suit the requirements of different
factories or the ideas of different manufacturers. In the single process, the
juice is received as usual in tanks, where it is treated with from 10 per cent,
to 20 per cent, of milk of lime, standing at 20° Brix. Attempts made to intro-
duce the lime in a dry state have not been successful, but to prevent the
considerable dilution that would be necessary if the lime were mixed with
water, the dilute washings from the filter presses have been substituted. But it
has been found that a badly filtering juice thereby results. The carbonation
may be performed in the vessels in which the juice is received, or the limed
juice may be run off into special tanks ; the exact amount of lime added not
being a matter of importance, the use of liming tanks is not essential.

In the double process, the first carbonation is performed in the vessels
in which the lime is added, after which the juice is filtered en masse or else
decanted and the scums only filtered. The cleared first carbonation juice is
then passed on to the saturation or second carbonation tanks where the process
is finished as already indicated.

It is general to keep the scums from the two carbonations entirely
separate, but in some beet sugar factories it is the custom to mix and filter
them together, a more easily treated material being thus obtained. This is a

264

THE CARBONATION PROCESS.

process not recommended by the best authorities, the interaction of the two
scums tending to reintroduce into the juice bodies which it is desired to
eliminate.

In the carbon ation process the quantity of lime used is very considerable
and it is essential that labour-saving devices be used in connection with it. A
factory of moderate size working up 5000 gallons of juice per hour will use
about 500 gallons of milk of lime, equivalent to about 500 Ibs. of dry lime.
The milk of lime may be mixed on the basement and elevated to the clarifier
loft by a pump or montjus, or the dry lime may itself be elevated by means of
a hoist. In either case power is required to drive the lime mixing apparatus.

FIG. 148.

This consists of a rectangular or cylindrical tank of suitable capacity, in
which is placed centrally a vertical shaft, fitted with a series of horizontal
blades. On the top of this shaft is fixed a horizontal bevel wheel gearing
with a vertical one which receives its motion by belt gearing from any con-
venient shafting, the power required not being sufficient to demand a separate
engine ; the liming tanks have similar appliances to ensure a complete mixture
of lime and juice.

265

CANE SUGAR.

Carbonating Tanks.— The carbonating or saturation tanks, Fig.
are made either rectangular or circular ; the latter form is preferable as tending
to a more uniform distribution of the carbon dioxide. They are often provided
with an iron lid, to which is fitted a short chimney. Where this device is not
utilized, the froth is broken up by means of a jet of steam brought to play
upon the surface. A mechanical arrangement, consisting of a scraper passing
over the surface of the juice, is sometimes used, and a stirring device, as shown
in Fig. 1£8, is also employed.

The height of the liquid undergoing treatment varies in practice from
4 to 9 ft., and owing to the frothing the vessels are not filled to within 1 or 2

FIG. 149.

ft. of the top of the containing vessel. No useful purpose is served by
decreasing the height of liquid, as if too low there is danger of carbon dioxide
passing away unutilized.

To distribute the gas uniformly through the liquid various devices are
used. The commonest method is to use a perforated coil, for which may be
substituted a perforated disc or drum : any method which secures uniform
distribution of gas is effective. In addition to the gas distributing coil, steam
coils are provided for boiling the juice ; an allowance of 1 square foot heating
surface for every two gallons capacity is sufficient.

266

THE CARBONATION PROCESS.

Gas Washer. — The carbon dioxide used in this process is, of course,
generated on the spot by burning limestone ; after being generated in the
kiln, the gas is passed through a gas washer, a form of which is shown in
Fig. 1JJ.9 ; it consists of an upright cylindrical vessel in which is placed a
series of transverse horizontal partitions e; in each of these, and projecting
a few inches, are fitted the funnels /; water is pumped into the vessel by
the pipe c and flows over the partitions, down through the funnels and out
through the pipe d. The gas from the kiln enters by the pipe a, the lower
end of which is perforated, and flows upwards in the direction indicated by
the arrows. In the passage of the gas the dust carried over is deposited and
the gas cooled down to a temperature of 40° C. Various other forms of gas
washers are made ; in one, perforated plates take the place of the transverse
partitions described above. Any of the forms of jet condensers described in
connection with evaporation serve equally well as gas washers.

In certain beet factories the gas evolved from the kiln is purified by being
passed through closely-packed carbonate of soda or through a solution of this
substance ; the object of this procedure is to eliminate any sulphurous acid
which may be present, as the coke employed contains sulphur.

Lime Kilns. — The carbon dioxide requisite for the carbonation process
is obtained by burning lime in kilns at the factory, which in this case makes
its own temper lime from crude limestone. Lime kilns are of two types,
continuous and intermittent, and the former of course is the type required for a
sugar factory. They may also be classed as long flame and short flame kilns.
In the former the fuel is burnt on a hearth, and the products of combustion
pass through the limestone in the kiln proper. In the latter the fuel and
limestone are mixed together and charged into the kiln from the top. It is
very general to use a combination of short and long flame burning. The latter
is more expensive as regards fuel, but gives a purer product, as in short flame
burning the lime is contaminated with the ash of the fuel. When using good
quality coke, with short flame burning, 2 per cent, of the product consists of
the ash of the fuel. When wood is used a rather larger percentage is
present.

In Fig. 150 is shown a section of a continuous type of kiln very generally
used in beet factories, which can be employed as a long or short flame kiln,
or as a combination of both methods. The kiln consists of a tapering masonry
shaft of forty to fifty feet high ; the diameter at the base is fifteen feet, and
at the beginning of the curved portion twelve feet. Many kilns are built with
much narrower shafts — a diameter of eight feet for a height of fifty feet not
being uncommon. The interior of the kiln is lined with fire-brick, d\ the
exterior being of common brick, e ; the whole is sometimes cased with iron
plates to prevent leakage of air through the masonry, and sometimes a layer
of non-conducting material is placed between the fire-brick and outer casing.

267

CANE SUGAR.

The base of the kiln is conical so as to allow the lime to gravitate towards the
doors, I, of which there are eight provided for the removal of the burnt lime.
The limestone, or mixture of limestone and fuel, is introduced into the kiln at
the top, which is kept closed by the cone, k. A charge being dumped on to
the cone from the waggon, h, the cone is lowered by moving the lever, m, and
distributes the charge evenly in the kiln. At / tubes are let into the wall to
allow of the process being watched. These tubes are provided with shutters
so as to regulate the supply of air. At a are the hearths on which the fuel is
burned, the products of combustion passing by way of c up through the kiln ;
three or four hearths are usually provided. The products of combustion pass
by tubes to the chamber I, whence they are aspirated by a pump to the gas

FIG. 150.

washer, and eventually to the carbonating tanks. The lime and fuel (where
the two are mixed) are raised to the platform at the top of the kiln by a
pulley hoist, and in very large installations by a hydraulic lift.

A very complete study of the lime kiln has been made by Gallois, from
whose researches the following notes are taken. The investigation, of course,
refers to beet sugar manufacture, but as the amount of lime used is the same
per ton of cane or beet, his results are applicable to the cane sugar industry.
Gallois' figures are expressed in the metric system, and these have been
converted by the writer to English units.

A lime kiln for short flame burning without hearths should have a
capacity of 14 cubic feet per ton of cane per 24 hours. For the decomposition

268

THE CARBONATION PROCESS.

of 100 Ibs. limestone of 95 per cent, purity, a theoretical minimum of 6 Ibs.
coke is required ; this corresponds to one volume coke to six volumes of lime-
stone. In practice, from four to five volumes of limestone are used with one
volume of coke, and some authorities allow three volumes.

Coke gives twice the calorific value of average wood, and accordingly 12
Ibs. wood to 100 Ibs. limestone would be required.

The following are the points to be observed to obtain a good result in
the kiln : —

1. The limestone should contain a minimum of silica and alumina.

2. Washed coke, containing not more than 7 per cent, of ash, should
be used.

3. The proportion of coke and limestone should be carefully regulated.

4. The charges should be frequent and regular.

5. The lime should be drawn successively from the doors in turn.

6. Only two-thirds of the volume of the kiln should be occupied,

7. The aspirating pump should work slowly and regularly.

8. Air should not be allowed to suck back through the gas pipe.

The objectionable constituents which occur in limestone are silica, alumina,
magnesia, and sulphate of lime. If either of the two former are present
during the calcination, fusible silicates and aluminates of lime and magnesia
are formed, giving rise to what is known as scaffolding in the kiln — «>., a
fused mass is formed, preventing the descent of the lime. In addition, their
presence prevents the lime slaking properly; furthermore, silica introduced
into the juice may dissolve in the presence of alkalies and be precipitated as
scale in the evaporators, besides causing difficulties in the filtration. Magnesia
;md sulphate of lime also cause scale in the evaporators.

Below are given analyses by MM. Gallois and Dupont of different types
of limestone : —

Material. Bad. Passable. Excellent.

Moisture .. .. 4-10 .. 6'25 .. 1-21

Sand, clay, and insoluble matter.. 4'50 .. 3'17 .. 0*55

Organic matter 1-20 .. 1-12 .. 0-41

Soluble silica .. 2-10 .. 0'64 .. 0*20

Oxides of iron and alumina . . . . 0*37 . . O'lo . . 0-23

Calcium carbonate (limestone) . . 85'86 . . 87'93 . . 96'58

Magnesium carbonate 0-95 . . O'o3 . . O'oO

Soda and potash . . 0'05 . . — . . —

Undetermined .. .. 0'87 .. 0'24 .. 0'32

269

CANE SUGAR.

The inefficient working of a kiln may arise from the following
points : —

1. Scaffolding, which may as already mentioned be caused by the presence
of silica or alumina, and also by careless work in changing or in mixing the
limestone and fuel.

2. "Withdrawal of unburnt lime when too little fuel is used or when com-
bustion is too rapid.

3. Presence of carbon monoxide, due to too little air being admitted for
complete combustion, or to a too low temperature in the kiln.

4. Presence of air due to leaks in the masonry or to air sucking back, or
to working the pump too fast.

The composition of the gas from the kilns varies within wide limits, the
theoretical maximum of carbon dioxide being 38- 7 per cent. ; in general
practice the percentage lies between 25 per cent, and 30 per cent., with from
1 per cent, to 3 per cent, of oxygen and 65 per cent, to 70 per cent, of
nitrogen. Traces of carbon monoxide may be present but should not rise
above 1 per cent. ; sulphur dioxide derived from sulphur in the coal may also
occur.

Carbonic Acid Gas Pumps. — The pumps used to aspirate the
carbon dioxide are now slide valve pumps similar in design and construction to
those used in the dry vacuum process described in the Chapter on Evaporation.
A table of their capacities is given below, taken from a Continental maker's
catalogue.

Quantity of gas sucked

'

per hour cb m.

50

825

1050

1300

1800

2050

3375

4050

Diameter of steam cylin-

der, mm.

275

350

375

400

470

500

600

700

Diameter of carbonic acid

A I w

\J\J\J

i \J\J

cylinder, mm

500

550

600

650

750

800

1000

1100

Piston stroke, mm

470

550

550

630

700

700

800

1000

Eevolutions per minute

75

70

70

65

60

60

55

45

Steam inlet, mm

60

80

80

90

110

110

140

170

Steam outlet, mm. .

70

90

90

100

120

120

150

185

Diameter of suction pipe,

mm.

110

125

135

150

175

190

240

270

Diameter of delivery

pipe, mm

100

110

125

140

160

170

220

250

270

THE CARBONATION PROCESS.

Review Of Process. — The essential question with regard to any new
process is whether a return is given on invested capital. An estimate of
necessary working expenses for a factory working 1000 tons of cane per day
over a crop of 100 days is given below.

The necessary extra plant over and above that needful for the ordinary
defecation process will include a limekiln, gas washer, and carbonic acid gas
pump ; and the carbonating tanks simply replace the clarifiers and eliminators
used in the defecation process.

The cost of these may be estimated as : limekiln, £3500 ; gas washer,
£150 ; carbonic acid pump, £600 ; a total cost of £4250.

The extra current expenses for a crop of 100,000 tons will include pur-
chase of limestone sufficient to give 1500 tons of lime, for which would be
required 2678 tons pure limestone, or, say, 2900 tons actual crude material.
In certain instances, such as in Mauritius, estates near the seaboard could
lay the coral reefs under contribution, and obtain limestone at the factory at
a cost of 2s. to 3s. per ton. Then the lowest cost of the limestone would be
£435, but in other cases, such as in Dernerara, the cost of transporting lime-
stone would be prohibitive.

In general, in beet sugar factories eight pounds of coke are required per
hundred pounds of limestone ; wood in tropical countries is as a rule cheaper
than coke, and, taking the relative calorific value of wood to coke as 1 : 3,
twenty-four pounds of wood will be required per hundred pounds of limestone,
thus for the 2900 tons of limestone 696 tons of wood ; in very favourably
situated estates wood can be obtained at the factory at a cost of 6s. per ton,
giving the cost of fuel as £208 16s.

The extra labour in working the kiln may be put at five men per shift,
and for the hundred days' campaign will cost £60.

The large quantity of water used with the milk of lime requires addi-
tional expense in evaporation ; if the 1500 tons lime be employed at a density of
20° Brix approximately 6000 tons of water are also added. Allowing at the
triple effect one pound of coal to evaporate twenty pounds water, 300 tons of
coal will be required, which, at 25s. per ton (a price frequently reached in the
tropics), will cost £375.

The total extra cost, then, allowing 10 per cent, interest and depreciation
on invested capital, will be for the 100,000 tons of cane £1508 16s., or 3-621
pence per ton of cane, and allowing a 10 per cent, recovery on the canes,
3s. per ton of sugar ; and this is an estimate made for circumstances more
favourable than would generally be the case.

To counterbalance this extra cost the value of the crop must be increased,
and an increase can only be looked for on the score of quality, as the figures
published by the West Java Experiment Station show conclusively that no-
greater extraction is obtained by this process.

271

CANE SUGAR.

In making high-class white sugars for direct consumption, an expenditure
of Is. 6d. to Is. 9d. for chemicals (including lime) per ton of sugar is usual.
The difference between this amount and that estimated as the expense of the
carbonation is really very small compared with the profits on a ton of sugar
expected to be realized on a large, well-managed estate. Very slight differ-
ences would turn the scale very decidedly in favour of one or other of the
processes.

What is, however, claimed as an advantage for the process is, in certain
cases, one of its greatest drawbacks, and that is the destruction of the glucose.
In countries such as Java and Mauritius, where either from excise reasons or
want of a market rum or arrack cannot be made, loss of glucose is of no
consequence, but in districts such as Demerara where the rum forms a very
important by-product, any destruction of glucose is a direct and serious loss,
which would at once put the process on an uneconomical basis. Where,
however, rum is not made, and fuel and limestone can be cheaply obtained
and a gummy impure juice is to be treated, the process might meet with
financial success.

REFERENCES IN CHAPTER XIV.

1. S. C., 334.

2. S. C., 313.

3. Arch., 1905, 197.

272

CHAPTER XV.

THE FILTRATION OF THE JUICE.

In a previous chapter, it was shown how the juice was separated into a
partially clear liquid and into a dirty liquor, formed out of the settlings and
the floating scum removed from the surface of the juice in the clarifiers ;

FIG. 151.

roughly ahout 90 per cent, of the juice will he obtained in the clear liquor
and 10 per cent, in the scums, the latter containing about 10 per cent, of
suspended solid matter. The scums are received in tanks where they are
limed and allowed to settle, the clear supernatant liquor being decanted and
added to the main bulk of the juice ; the scums are then passed through the
filter presses, the clear filtered liqnor being passed on to the evaporators.

273

18

CANE SUGAR.

274

THE FILTRATION OF THE JUICE.

In some factories the partially clarified liquor is also filtered en masse
in filters known as ' mechanical filters ' ; in others the juice is cleaned hy
boiling, and by skimming off the floating impurities; the vessels in which thi&
process is carried on are known as 'eliminators' and in Java as 'Fletcher pans.'

Taylor Bag Filters. — The Taylor bag filter consists of stockings
of stout cloth, generally about six feet long and four inches in diameter; these
stockings are suspended in groups of from twenty to fifty in a horizontal
frame ; the frame is perforated with holes in rows a short distance apart ; into-
the holes are fitted gun metal sockets furnished with screw threads for the
reception of the gun metal cones to which the bags are tied. The whole
system of frame and bags is enclosed in an upright iron box, access to which
is afforded by means of close-fitting doors; the sides of this box project a
height of about two feet above the frame ; the scums being allowed to flow
over the frame, the clear juice passes through, the dirt being retained in the
stockings. A steam connection is usually fitted up in the interior of the box
so that the high temperature necessary to rapid filtration may be maintained,
A view partly in section and partly in elevation is shown in Fig. 151.

Frame Filter Press. — In Fig. 152 is shown a view partly in
section and partly in elevation of a central feed frame filter press ; it consists of
a heavy cast-iron frame 3, on which are supported a number of plates c ; on
the sides of the plates are cast lugs from which the plates depend. The latter
are made either square or circular, generally the former. On their surface
are formed a number of corrugations about one quarter of an inch deep ; in
the centre of each is an opening so that when all the plates are fixed in position
there is a circular conduit running through the press. Near a lower angle of
each plate is an aperture which communicates by a channel with a cock placed
at the bottom of one of the sides of the plate, and through which the filtered
juice is drawn off. Filtration is made through strong twill cloth as a general
rule, but in the absence of other material ordinary gunny bags form an
efficient substitute. Cloths, with circular holes cut to correspond with the
holes in the plates, are hung over each plate. The edge ef the cloth is securer!
in the hole in the plate by means of a hollow screw with a deep rim. In
working the press after all the cloths have been placed in position, the whole
is screwed tight by means of levers acting on the wheel e, which works the
screw thread /, and by means of suitable piping juice is pumped or forced by
a montjus through the press along the conduit g ; the clean juice passes
through the cloth and the suspended dirt is caught between the cloths. At the
upper corners of the plates are openings communicating with another set of
piping by means of which water or steam may be forced through the scum
after the press is filled. This type of press is not very convenient ; the bags
have a great tendency to tear away at the centre, and washing to remove

275

CANE SUGAR.

sugar in the cake is not, as a rule, effective. A rather different system is now
usually followed. In Fig. 158 are shown, in section, the types of plate used.
One plate is solid, and the other consists of a frame only, a. The solid and
hollow plates are placed in the press alternately. At the angles of both frame
and press are the circular openings b and c, so that in this press there are two
conduits, that at b is for the passage of the juice, and that at c for the washing
water. The channel h, in the hollow plates, conducts juice to the interior of
the press, and in the solid plates there is a similar channel i. A light joint is
made along the conduits by placing indiarubber rings, d, in the closed openings
b or c, as the case may be. At g in the solid plate is an opening communi-
cating with the cock/. Bags without openings are hung over the solid plates?
but do not cover the conduits b or c. Scums being forced into the press by
the conduit b, pass through the channels h and fill the spaces between the two
solid plates formed by the hollow plates. The clear juice passes out through

<gr

IDC:
/i

FIG. 153.

g, the scums being caught between the bags. To wash the cake, water is
forced through the conduit c, and passes through the cake in a direction
opposite to that by which the juice travelled. The advantage of this type of
press over the central feed press is that the washing is more effectively per-
formed, and that the bags not needing to be cut have a longer life.

Capacity of Filter Presses.— To filter scums an allowance of
two square feet of filtering area for every gallon per hour is necessary, and
taking the scums as 10 per cent, of the volume of the juice, two square feet
of filtering area should be allowed for every 10 gallons of juice per hour ; this
is a minimum allowance and should be increased at least 25 per cent, to allow
for time lost in changing cloths, &c. Where, as now is often the case, the
scums are thoroughly washed, or are re-pressed, a greatly increased capacity
is called for.

276

THE FILTRATION OF THE JUICE.

Loss of Sugar in Presses. — The loss of sugar in the presses
depends on the purity of the juice, as influencing the amount of cake formed,
and the degree to which the washing is carried. With the Taylor niters a
cake containing from 65 per cent, to 70 per cent, of water, and which cannot
be easily washed, is obtained ; a loss of 2 per cent, of the sugar in the juice
can easily occur here. With frame filter presses a cake containing from
50 to 55 per cent, of water and weighing from 1 to 1*5 per cent, of
the juice is obtained, and this cake without washing will contain from
•8 to 1 per cent, of the sugar in the juice. This loss can be almost entirely
recovered by washing; the limit to which this washing can be carried
depends on the evaporative capacity of the factory, and on the filtering
area available. In the Hawaiian Islands many factories wash the cake
until it contains no more than 1 per cent, of sugar ; the loss in this case is
very small and less than '1 per cent, of the sugar in the juice. It should be
noticed that it is only in large factories that so complete an exhaustion can be
obtained. In a factory turning out annually 50,000 tons of sugar, a loss of
1 per cent, of the sugar entering with the juice indicates a loss of 500 tons
of sugar, and it will be economical to erect plant capable of dealing with this
loss; in a smaller factory making only 5000 tons of sugar, the erection of
plant to recover the 50 tons of sugar might be uneconomical, as the larger loss
would be recovered at a much lower pro rata cost.

The very dilute last washings are often employed at the mill as a
macerating agent ; it should be remembered however that, as these washings
are alkaline, there is a tendency towards dissolving out gummy bodies from the
megass. In beet factories these washings are used in mixing the milk of limer
of which much larger quantities are used than in cane factories.

Double Pressing. — In some factories the cake is not washed directly
in the presses, but is discharged without washing, and remixed with a quantity
of water ; the mud is then passed a second time through the presses.

Difficulties in Filtration. — In certain cases, a mud, from which it
is impossible to obtain a firm cake, results and such a cake is incapable of
washing ; the cause of this is probably to be found in the presence of gums or
of pectinous bodies in the juice, and is more likely to occur when unripe canes
are being milled ; in such a case, a better cake may sometimes be obtained by
forming in the scums a granular precipitate of oxalate of lime; about 1 per
cent, of a saturated solution of oxalic acid is added to the scums, followed by
enough lime to restore the alkaline reaction.

Filter Press Pumps. — In many instances the scums are forced
through the presses by means of montjus ; a montjus (Fig. 15Jj.), consists of a
cylindrical vessel a a ; it is filled by the funnel b ; the cock c communicates

277

CANE SUGAR.

with the main steam pipe ; when the vessel is filled and the cock on the
funnel b is closed, the cock c is opened and the pressure of the steam forces
the scums through the pipe d, communicating with the press ; the emptying
of the montjus is indicated by the escape of steam through the pipe e.
Montjus are usually worked in pairs so that their action is nearly continuous.
Instead of montjus, pumps are preferable ; those in common use are duplex
pumps, which by a simple arrangement are automatic, stopping when the

FIG. 154.

pressure in the press which they are filling reaches a certain limit ; a small
pipe coming from the air vessel of the pump communicates whatever pressure
there is in the air vessel to an arrangement which controls the steam valve ;
when the pressure reaches a limit which can be regulated, the steam valve is
closed, and the pump stops working. When communication with the filled
press is cut off, and the pump connected on to the next press to be filled the
pressure is relieved, and the pump automatically starts working. Several
patented forms involving the control of the steam valve by the pressure
in the air chamber are on the market ; those the writer has encountered
have been of German make and are sometimes referred to as ' German
pumps.'

278

THE FILTRATION OF THE JUICE.

Mechanical Filtration. — Filtration of the juice after separation
from the scurns is practically universal in beet sugar factories and should
always be made in cane sugar factories where high-class sugars are
being made ; the nitration is made in what are termed mechanical filters,
a large number of different designs, differing only in detail, being in
existence.

In Fig. 155 are shown sections at right angles to each other of a common
type. The filter consists of an iron box provided with a false lid in which
are kfixed frames a. These frames consist of a lattice work skeleton over
which is stretched a woven fabric, each frame is complete in itself and is
called an element. A separate outlet is provided for each element so that any
faulty ^one can be shut off. All the elements discharge into one common
gutter. The juice enters the box at d, fills the box below the level of the

FIG. 155.

false lid and passing from the outside to the inside of the elements discharges
at b. In the form shown the elements are rectangular, while in some other
designs they consist of cylinders, but the principle is the same in all. These
filters are generally made with elements of one square metre filtering area,
counting, of course, both sides, and in a chamber there will usually be about
twenty to thirty elements. The filters will pass on an average 10 gallons
of juice per square foot per hour, but as much time is lost in changing cloths,
they should not be calculated to pass more than seven gallons per foot per
hour. They are also sometimes used to filter syrup on its way to the pans
from the triple. When used for this purpose, their capacity is only one-third
or one-fourth of what it is for juice. They are usually worked under a head
of 6 or 7 ft.

279

CANE SUGAR.

Sand Filtration. — In Fig. 156 is shown the general type of appar-
atus used for sand nitration ; it consists of a cylinder a a about 6 ft. high,
and 2 ft. in diameter ; within the cylinder is arranged a perforated pipe I b
about 8 in. in diameter ; between the pipe and the outer casing are a number
of conical rings, each about 3 in. high, and standing one on top of the other ;
the space between the central pipe and these rings is filled with sand ; the
juice or other material to be filtered enters by the pipe c c, fills the cylinder,
passes through the sand into the perforated pipe and is discharged through
the pipe dd\ the sand when foul is discharged through a manhole at the
bottom of the cylinder and is easily washed in a stream of water. The

FIG. 156.

perforations in the pipe are of such a size that the sand does not pass through.
The capacity of these filters varies with the nature of the juice and with the
size of the grains of sand used ; as a general rule two filters of the size quoted
above should be sufficient for every 1000 gallons of juice per hour..

The advantages of mechanical or of sand filtration are most pronounced
when high class direct consumption sugars are being made, and to this end they
form an invaluable adjunct to the factory ; it has also been found that they
remove large quantities of suspended matter, and have a very useful effect in
lessening the deposit of scale in the evaporators, and thus materially adding
to their capacity.

280

THE FILTRATION OF THE JUICE.

Filtration through Wire Gauze.— A very useful effect is
obtained by passing the juice through very fine wire gauze strainers ; for this
purpose a mesh of 100 strands per lineal inch is useful ; the writer has seen
high class consumption sugars made with the help of these strainers, with
suppression of the cleaning of the juice by boiling in open pans.

Other Filtering Media.— In addition to sand many other filtering
media have been proposed for use ; amongst these may be mentioned megass,
wood shavings, coke, chopped cork, pumice stone, slag wool, broken brick,
lignite, gravel ; of these the writer has seen fine wood shavings sold under the
trade name of Excelsior Packing used with great success. When these media
are used they are packed in vertical cylinders through which the juice is
allowed to gravitate ; the type of filter described under Sand Filter forms a
very convenient pattern.

Composition of Press Cake. — The composition of press cake is
shown in the following analyses due to Prinsen Geerligs : —

Double Double

Carbonation Carbonation

Second
Saturation.

8-10

•50
4-20

•64
•51

85-01

•12

•82

Defecation

Single

First

Process. Carbonation. Saturati

Water .. .. . .

69-72 . .

—

—

Sugar

10-20 . .

3-90 . .

10-10

Glucose

•71 ..

—

•38

Wax

4-12 ..

3-43 . .

2-48

Albumen

1-80 . .

2-55 . .

2-72

Fibre

— . .

3-08 . .

6-10

Organic acids

—

1-94 . .

2-12

Gums ....

—

1-11 ..

1-20

Phosphate of lime . .

2-92 . .

—

—

Silica ...

•37 ..

8-48 . .

1-85

Iron and alumina . .

1-40 ..

2-41 ..

4-66

Magnesia

•22 . .

—

—

Sand and clay

2-82 ..

2-48 ..

4-37

Calcium carbonate . .

—

67-94 . .

61-94

Magnesium ,,

—

1-80 ..

1-21

Phosphoric acid

—

•71 ..

•87

Undetermined . .

5-35

•17

281

CHAPTEE XYI.

THE EVAPORATION OF THE JUICE TO SYRUP.

By evaporation is meant the passage of a body from the liquid to the
gaseous state. The term evaporation is usually restricted to that change
which takes place continuously at the surface of a liquid, and ebullition or
boiling to that which takes place throughout the entire mass.

Evaporation takes place continuously at the surface of all exposed liquids.
The molecules or particles of matter, of which all bodies are supposed to be
composed, have in a liquid but little attraction for each other, and tend
constantly to fly off into space. In an enclosed liquid a quantity of vapour
will be formed above the surface. The molecules of the liquid, in the form of
vapour, are in constant movement, and will in their paths to and fro impinge
on the surface of the liquid, which is at the same time constantly giving off
vapour; eventually a point is reached when as many molecules leave the
liquid as enter, so that a system in equilibrium obtains. When this state is
reached the space above the liquid is said to be saturated, and no more
evaporation (apparently) takes place.

The vapour given off by a liquid exerts a certain pressure which increases
with the temperature ; this pressure is known as the vapour tension. When
the vapour tension of the liquid is equal to the pressure of the surrounding
atmosphere, bubbles of vapour form in all parts of the liquid, and the latter is
said to boil ; the boiling point of a liquid is then not a fixed figure, but is
dependent on the pressure under which it occurs. The normal pressure of the
atmosphere at sea level is equal to that exercised by a column of mercury
29-92 inches or -760 metre high; this is equal to a pressure of 14707 Ibs. per
square inch or to 1-034 kilogram per square cm. At this pressure water boils
at a temperature of 212°F. or 100°C. ; if the pressure be decreased the
boiling-point of water of any liquid falls, and it is due to this phenomenon that
multiple effect evaporating apparatuses can be constructed, in which 1 Ib.
of steam may evaporate in practice up to 5 or 6 Ibs. of water. A table is
added at the end of this chapter, giving data connecting the pressure and
temperature of steam. The temperature at which a liquid boils is also
influenced by the presence of bodies in solution ; a table of the boiling-
points of sugar solutions under atmospheric pressure will be found elsewhere.

282

THE EVAPORATION OF THE JUICE TO SYRUP.

Latent Heat. — When water or any liquid passes into the form of
vapour, a certain quantity of heat is required to perform this change ; this
quantity is called the latent heat of evaporation. The heat required to raise
the temperature of I Ib. of water one degree Fahrenheit is called the
British Thermal Unit, or B.T.V., and to convert lib. of water at 212° F.
into steam at 212° F. requires 966 B.T.U. This quantity is the latent heat of
evaporation of water. A quantity often used in calculation is the total heat of
ateam ; this means the quantity of heat required to convert 1 Ib. of water
from the freezing point (32° F. or 0° C.) to steam at the given temperature.
Thus to raise the temperature of lib. of water from 32° F. to 212°F.
requires 180 B.T.TJ. ; to convert it into steam requires 966 B.T.U., so that
the total heat of steam at 212° F. is 1146 B.T.U. The metrical unit of heat
is the quantity of heat required to raise one kilo, of water through 1° C. ; it is
called a Calorie, and is 3-967 times as large as the B.T.TJ.

Conversely to what has been written above, when steam is condensed to
water it gives out the heat which was required to convert the water to steam.
If then steam at 212° F. be condensed to water at 180° F. it gives up a quan-
tity of heat which is the difference between the total heat of steam at 212°F.
and of water at 180° F. This heat can be used to raise the temperature of or
to evaporate water which is under such a pressure that its boiling point is
lower than 180° F. ; the vapour or steam given off by the water thus caused
to boil may be used to boil more water under a still lower pressure, and so on,
and this process repeated to infinity. It is on these lines that the construction
of multiple effect apparatuses is based.

Standards of Pressure and Vacuum.— The normal pressure
of the atmosphere is 14-707 Ibs. per square inch and it will support a column
of mercury 29 '92 inches high ; in the metric system the corresponding measures
are 1-034 kilos per square cm., and a barometric height of '760 metre. Pres-
sures are also expressed in atmospheres and we thus have 1 Ib. per square
inch = 2-035 inches of mercury = -068 atmosphere. The vacuum in an
effect is nearly always given in inches of mercury ; thus, a vacuum of 25 inches
means that the excess of atmospheric pressure over the pressure in the effect
would support a column of mercury 25 inches high; hence expressed as a
pressure a vacuum of 25 inches means a pressure of 29-92 — 25 inches =
4-92 inches = 2-42 Ibs. per square inch.

Transmission of Heat. — The coefficient of transmission of heat
is the quantity of heat which will pass in one minute from a warmer to a
colder surface of one square foot area under a difference in temperature of
1°F. The metrical units of reference are the square metre, degree Centigrade,
and the calorie. The metric coefficient is then 4 -88 times as great as the
British coefficient.

283

CANE SUGAR.

The transmission of heat is governed by the following Laws : —

1. It is directly proportional to the mean difference of temperature.

2. It varies with the nature of the material through which the heat
passes. The hest conductors of heat are metals, silver and copper in particular ;
copper or brass are the two materials most used in practice.

3. The coefficient of transmission decreases with increasing thickness of
metal ; for copper, however, within the thicknesses employed in practice the
coefficient is sensibly constant, and even with brass 5 per cent, would be an
extreme variation.

4. The coefficient of transmission is affected by the nature of the
substances on either side of the partition ; thick viscid liquids as occur in the
last body of a multiple effect greatly retard the passage of heat as compared
with water. In an extreme case it may be only one-fifth of what it is when
dealing with water.

5. Incrustations, such as occur on the tubes of a multiple effect, have an
enormous and undeterminable effect in reducing the passage of heat.

6. The larger the heating surface, i.e., the partition separating the
substances between which a transfer of heat occurs, the less is its efficiency ;
that the efficiency is proportional to the square root of the surface has been
established for tubes internally steam heated, and the same relation probably
holds for externally heated tubes.

7. The transmission is also affected by the position of the heating
surface ; thus with vertical tubes the condensed water which is formed on the
surface of the tubes flows down them and prevents intimate contact of steam
and heating surface. With horizontal tubes the condensed water drops off the
tubes and the latter are in general more efficient. Any form of apparatus
which permits easy and rapid removal of condensed water is per se more
efficient than one which does not fulfil those conditions.

8. The heat transmitted increases with the rapidity of circulation of the
liquid being heated, and is greatly increased if the liquid should actually boil.

The proposition enunciated in Law 1 requires some elaboration, and is
only approximately true ; the heat transmitted through a partition, one side of
which is at 60°C. and the other 58°C. is twice as great as that transmitted
when one side is at 60°C. and the other at 59°C., but it does not follow that
in the latter case the heat transmitted is the same as when one side is at
120°C. and the other at 119°C., although the temperature difference is exactly
the same. Actually, Olaassen has shown that at higher temperatures the coeffi-
cient of transmission is much greater than at lower ones; hence it follows
that a fall in temperature due to high vacuum in the last body of a multiple is
not attended with so much benefit as in cases where the temperatures are more

284

THE EVAPORATION OF THE JUICE TO SYRUP.

elevated. Claassen1 estimates that no practical benefit is obtained by in-
creasing the vacuum, in the last body above 60 cm. (= 23'7 ins.), as the
decrease in the coefficient of transmission is sufficient to neutralize the increase
in difference of temperatures.

The effect of the velocity of the juice has been experimentally studied by
Porkong2, whose data are as follows : —

With a velocity of juice 1*29 metres per second, the calories transmitted
per minute and per square metre were, per 1°C. difference in temperature,
8-15, and with velocities 1'Soand 1*523 the corresponding calories were 16*25
and 17-71.

The coefficients of transmission under actual conditions have been studied
by Jelinek and by Claassen3. Their results are given below : —

Triple First vessel 37 calories.

Second vessel 25 ,,

Third vessel 14

Quadruple First vessel 28 , ,

Second vessel 26 ,,

Third vessel 20

Fourth vessel 5-6 ,,

Vacuum pan . . . . Graining 18 ,,

Boiling .. .... . . 10

Bringing up 3-7 ,,

Vacuum pan for low products 6-7 ,,

(Jelinek).

Fore evaporator 50 calories.

Quadruple First vessel 45 , ,

Second vessel 30 ,,

Third vessel . . . . 20

Fourth vessel 12 „

Eeheating diffusion juices, carbonation juices and

syrups 5 ,,

Vacuum pan first products 10 ,,

,, ,, low products 5 ,,

(Claassen.)

The calories here given are metric calories. The low transmission
coefficients found with heating juices as compared with those found with the
juices in the evaporator are due to the fact that in the latter case the juices
are actually boiling.

Superheated Steam. — Superheated steam is a much worse conductor
of heat than is saturated steam, and hence the loss of heat in steam pipes is
much less with superheated steam than with saturated ; in addition, super-
heated steam can be used more economically in the cylinder of an engine

285

CANE SUGAR.

than can saturated steam ; the very reasons that make superheated steam
advantageous for use in engines prevent its satisfactory use for evaporation,
where a rapid condensation and quick transference of heat is required.

Early Methods. — The earliest method of evaporation was in pots
over a naked fire, a system still pursued by the ryots of India and on a fairly
large scale in Barbados, the whole system of tayches being called a copper wall.
The earliest improvement over this method was the introduction of steam-heated
pans, followed by the Aspinall, Wetzel, and other devices ; all these consisted
essentially of an open pan in which revolved steam-heated coils or discs, so
arranged that half the coil was immersed ; the rotating coil carried upwards a
thin film of liquid and thus exposed a large surface to evaporation.

In 1865, Fryer introduced the Concretor, a patent which has been
extensively used. In this plant the thin juice flows over a series of trays
placed over a flue, the whole being built on a slight incline ; the flue is about

FIG. 157.

forty feet long and the juice travels in a zigzag path about two hundred feet ;
reaching the end at a density of about 50° Brix, it flows into a revolving
cylindrical vessel, in the interior of which are fitted scroll-shaped plates, so
that, as the cylinder revolves, a large surface is exposed to evaporation ; at the
same time a current of hot air is blown through. After twenty minutes'
treatment in this cylinder the evaporated juice sets on cooling to a solid mass,
and is shipped to refineries for further treatment.

A modernized form of this scheme is used in Miller's patent employed in
the manufacture of * basket ' sugar in the Straits ; the final concentration is
effected by a revolving coil containing heated oil, the temperature of which
can be regulated.

286

THE EVAPORATION OF THE JUICE TO SYRUP.

Multiple Evaporation. — In modern factories evaporation is always
performed in multiple evaporators. The principle on which these are con-
structed has already been indicated. The first multiple evaporator was
invented in 1834 by Nbrbert Killieux, of Louisiana, and was a double effect
horizontal submerged tube apparatus. Apparatuses conforming to his original
design and only differing in mechanical details are still constructed.

In Fig. 157 is shown a diagrammatic sketch of a vertical submerged tube
triple effect apparatus. Each body consists of an upright cylindrical vessel of
height rather more than twice the diameter ; near to the bottom and at about
one-third the height are placed two tube plates : these plates cany a number of
tubes, the space between the tube plates and external to the tubes being filled
with steam or vapour from a preceding effect ; the vapours pass over from the
juice in one vessel to the calandria of the next by means of the vapour pipe c.
In each vapour pipe is often placed a cylindrical baffle plate d for the purpose
of intercepting any juice carried over in entrainment : any juice so intercepted
is returned by the pipe e to the vessels. The juice circulates from vessel to
vessel by the pipes /under the influence of a difference in pressure or aided
by a circulating pump ; the concentrated juice from the last body is pumped
out against atmospheric pressure ; very often this pump is worked off the
main vacuum pump. The water of condensation in the calandrias of the
vessels passes out through the pipe «'; generally steam traps of various con-
structions are used or the water may be removed by a small pump. In some
designs the water of condensation is passed from vessel to vessel, affording a
slight economy of heat. The pipe h is for the purpose of introducing acid or
alkali to cleanse the tubes of scale and j is a small pipe carrying the incon-
densible gases from the second to the third vessel and thence to the pump.

The method of operation is as follows : juice is allowed to flow into the
vessels from the supply tank until a little above the level of the upper tube
plate ; the vacuum pump is then started, and a vacuum of about 25 inches,
corresponding to a pressure of about 5 inches, is obtained in the last body of the
apparatus, and the water injection cock opened. Exhaust steam at a pressure
of about 5 Ibs. per square inch is admitted to the calandria of the first body ;
the juice boils and vapour passes over into the calandria of the second body,
into which juice from the first body has already passed; the tubes in the
second body act as a surface condenser to this vapour. The condensation of
this latter creates a partial vacuum in the first body, and by its condensation
parts with its latent heat to the juice in the second body, causing this juice to
boil. A similar process takes place between the second and third bodies, and
so on.

In this way 1 Ib. of steam could evaporate an infinite quantity of water ;
for reasons explained later on, the practical working limit is generally granted
to be reached with quadruple evaporation. The majority of apparatuses are,
however, triple effects ; but quintuple plants have been constructed.

287

CANE SUGAR.

FIG. 158.

288

THE EVAPORATION OF THE JUICE TO SYRUP.

Apparatus for multiple evaporation may be divided into three classes: —

1 . Vertical submerged tube apparatus, often referred to as the * standard*
type.

2. Horizontal submerged tube apparatus, conforming to the original
Rillieux and including the Welner-JelineJc apparatus.

3. Film evaporators, including the Lillie, Yaryan, and Kestner
patents.

Vertical Submerged Tube Evaporator.- In Fig. 158 is
shown a section of one vessel of a vertical tube apparatus. At a are the tubes
outside which circulates the heating steam, the juice being contained within
the tubes and above and below the tube plates ; at b is an opening in the
centre of the tube plate forming a large central circulating tube ; at c is the
juice intake pipe dipping down to near the bottom of the vessel ; at d is a pipe
through which is drawn off the condensed water ; at e is a pipe through which
the incondensible gases are drawn off.

The Calandria or tubular cluster consists
of two tube plates into which are expanded
the tubes ; the tube plates are usually fixed
to the wall of the containing vessel, but in
some designs the calandria has its own side
walls, an annular space being then formed
between the interior of the vessel and the
exterior of the calandria. The large
central tube is for the purpose of providing
a circulation, and is very generally found;
in other designs the circulating tube is not
placed centrally, but at the side. The
tubes are usually made of brass, but
copper is sometimes used, and in some
German designs the tubes are made of
mild steel. The diameter of the tubes
is generally about two inches ; in earlier
plants the length of the tubes reached up
FIG. 159. £0 ag much as sjx fee£ or more> tut now

•four feet is a usual length ; it will be shown later that a great length of
rtube may be detrimental to the efficiency.

The distribution of the heating steam has a great effect on the efficiency ;
;if the steam enter at one place only, that part of the heating surface remote
from the steam entry tends to become inefficient, and there is also a tendency
for incondensible gases to bank up. In the design shown the heating steam
^passes into a belt surrounding the calandria ; in other designs the steam or

289

19

CANE SUGAR.

vapour enters the calandria in as many as six places. To further secure an
even distribution of steam it is not unusual to divide the calandria into
compartments by means of partition plates.

Stillman Evaporator.— This design externally resembles the
' Standard'; the tubes however project about 6 inches above the upper tube
plate, and are up to 7 feet in length ; the liquor level is kept at about half the
height of the tubes: the juice creeps up the tubes, overflows on to the tube plate,

FIG. 160.

and passes down a central tube of large diameter to the next effect in series.
This evaporator belongs to the ' film ' type and has a high efficiency ; the only
one the writer has seen would have been improved by a larger vapour space.

Chapman's Evaporator. — Of special forms of the vertical tube-
evaporator, Chapman's design, Fig. 159, may be mentioned. The juice enters
at a, and flows upwards through the tubes and down through the funnel I. In
the form sketched the vessel is divided into two parts by a vertical partition,
affording a double circulation ; in others the juice passes directly from vessel
to vessel. Circulation between the different bodies is obtained by means of

290

THE EVAPORATION OF THE JUICE TO SYRUP.

inverted syphons connecting the discharge of one with the intake of the next
body, and these are of such a length that the leg connected with the second
body is from 12 to 18 inches longer than the column of liquid which is due
to the greatest pressure that can be possibly obtained between the two vessels.
This apparatus is to a large extent self adjusting; there is only one cock to
control the flow of the juice into the apparatus, and the system of circulation
prevents the juice in any vessel rising much above the level of the tube plate.

FIG. 161.

Hagemann Evaporator. — This specialized type of standard
evaporator is shown in Fig. 160. The peculiar points in this design are the
automatic regulation of the flow of the juice by traps a and by the juice-
trays b taking the place of the syphons in Chapman's design ; the horizontal
baffles c in the calandria ensure the action of the hottest steam at the upper
level of juice and the vertical baffles d give an up and down circulation to the
juice.

291

CANE SUGAR.

The Horizontal Tube Apparatus.— The horizontal submerged
tube apparatus differs from the above in that the steam or vapour is contained
within the tubes, the juice under treatment being outside ; a longitudinal
section of this form is shown in Fig. 161. The evaporating tubes are from 5
to 6 feet long, and are supported by vertical tube plates placed about 12 inches
from the end; steam enters at the side at/, passes through the tubes, and after
condensation is trapped at h ; to facilitate the passage of the water the tubes
are often set at a slight incline. It will be seen that the level of the juice
in the vessels is, relatively, much higher than in the vertical type. To prevent
^ntrainment losses a very capacious steam chamber is placed over each vessel ;
the vapour main leads from this steam chamber to the calandria of the
following effect. Plants of this type are not usually made by English firms,
who prefer the vertical form ; they are made to a certain extent in America,
and are very largely used in Austria and Russia.

FIG. 162.

In this type of evaporator the incondensible gases are swept forward by
the steam and collect in the space at the end of the tube run, whence they are
removed through i ; removal of the gases is much easier in this form of
apparatus than in the vertical tube design.

In Fig. 162 is shown a longitudinal section of a cylindrical Rillieux
apparatus, as made by the Newhall Manufacturing Co. ; it differs from other
plants in the low vapour space above the boiling liquid ; losses due to entrain-
ment are prevented by the horizontal baffle plate at a a and by the vertical
plates at 1 1 ; these last extend only half-way across the shell and are attached
alternately to opposite sides. This apparatus conforms very closely to the
original Rillieux design.

292

THE EVAPORATION OF THE JUICE TO SYRUP.

FIG. 163.

293

CANE SUGAR.

FIG. 164.

294

THE EVAPORATION OF THE JUICE TO SYRUP.

The Welner - Jelinek.— The Welner-Jelinek evaporator is a
horizontal submerged tube apparatus differing very materially from the above,
and is designed initially to have the height of the column of liquid under
treatment as small as possible ; the evaporating tubes are shown in end
elevation and longitudinal section in Figs. 163 and 16!].. They are about
twelve feet long and three-quarters of an inch in diameter ; they are supported
by tube plates at either end and by two intermediate tube plates shown at /;
the tubes are generally arranged in nests of nine. The length and small

TT T

FIG. 165.

diameter of the tubes necessitates the use of the intermediate tube plates, but
at the expense of the longitudinal circulation. On reference to the drawing,
Fig. 164, it will be seen that the steam or vapour entering at the valves /
circulates through three sets of tubes ; the rush of steam carries the condensed
water along with it, the latter being trapped at h in the boxes at the end of
the run. In some designs the condensed water is also trapped in the return
boxes. The level of the juice under treatment is shown at k, the vertical
height being only from 22 to 24 inches. The juice enters at m and leaves by

295

CANE SUGAR.

the pipe g ; a minute air vent is placed in the condensed water box at i.
Above the main vessel, and communicating with it by two pipes c, is placed a
save-all J, from which passes the vapour pipe to the next effect. Compared
with the horizontal apparatus of the Billieux type, the relatively small
height of the column of juice, the large vapour space, and the method of steam
circulation, are to be noted. This type has been extensively used on the
Continent of Europe, and especially so in Austria.

Swenson Evaporator. — This evaporator follows the general form
of the Welner-Jelinek, from which it may be regarded as derived ; the tubes
are not expanded into the tube plate but a tight joint is made by means of
rubber rings.

FIG. 166.

Stage Evaporation. — In order to minimize the effect of the
hydrostatic pressure (of. infra] the heating surface of the horizontal tube
evaporators is sometimes divided into stages whereby a low level of juice is
obtained : this method is shown in Fig. 165, which represents a section of a
Newall horizontal tube apparatus. Each stage has its own juice connections
and separate vapour intake ; the vapours from the stages combine, those from
the lower stage passing upwards between the shell and the upper stage. In
the Welner-Jelinek and Swenson patterns the vapour uptake from the lower
stage is arranged through a passage in the centre of the upper stage.

The Zaremba Evaporator also may be regarded as derived from
the Welner-Jelinek : the shell of this apparatus is a vertical cylinder, a
calandria of rectangular section being arranged in the lower part. This
apparatus is shown diagrammatically in Fig. 166.

296

THE EVAPORATION OF THE JUICE TO SYRUP.

297

CANE SUGAR.

The Yaryan. — The Yaryan eYaporator, shown in longitudinal section
in Fig. 167, and in end sectional elevation in Fig. 168, consists of a horizontal
body or shell of steel plate or cast-iron — depending upon size and steam
pressure — within which is grouped a series of tubes about 3 inches diameter ;
these tubes are expanded into the tube plates as shown, and at each end
* return heads ' are bolted on, thus forming a connection which ensures the
continuous flow of the liquor through each coil or tube system.

Steam, or vapour from a preceding shell or effect, enters the shell at e
and surrounds the outside of the tubes containing the liquor to be evaporated.

d

FIG. 168.

The liquor entering pipe d is forced, under pressure by a pump or
otherwise, into the top tubes, and only partially fills their bore, thereby
allowing space for the vapour arising from the heated liquor to pass freely
away. The liquor passes along with a rapid and continuous motion through
the series of tubes and discharges at g, the concentrated liquor and its vapour,
passing along pipe/, falls into the separator h, shown in section in Fig. 168.
The vapour passes, as indicated by the arrows, up and down the two baffle
plates b b, where it emerges into pipe k which leads direct to shell of next
vessel, or to condenser if from the last effect.

298

THE EVAPORATION OF THE JUICE TO SYRUP.

The concentrated liquor falls to the bottom of separator h and passes along
pipe i to the next shell for further concentration, and so on until, sufficiently
concentrated, it has reached the last effect, when it has then to be pumped
out owing to its being treated in a vacuum.

The Lillie. — The Lillie horizontal tube film evaporator offers a system
of evaporation radically distinct in mechanical details from any of the above.
A vertical longitudinal section is given in Fig. 169, and in Fig. 170 is shown
an end elevation. The evaporating tubes are 5 to 6 feet long and 3 inches in

FIG. 169.

diameter"; they are expanded into a tube plate at one end only to allow free
expansion and are set at a slight incline to afford easy escape of condensed
water ; each tube has its own air vent at the end opposite to the tube plate. The
juice is circulated by means of centrifugal pumps c all worked off one shaft;
these pumps are of sufficient power to force the syrup out against atmospheric
pressure. The supply of juice enters through the balanced valve operated by
the float resting on the surface of the liquor in the float box /, and which
permits the thin liquor to enter the effect and be added to the circulating

299

CANE SUGAR.

liquor just fast enough to replace that passing away as vapour and through
the discharge. The latter is controlled by the hand valve g ; by opening it
the discharge is increased, causing the level of the liquor in the float box to
fall, and admitting a larger feed. The path of the juice is from the float box,
through the pump and connecting piping up into the manifold box on the
back of the tube plate, thence into the several distributing tubes through the
slots of which it passes as a fine shower over the evaporating tubes to the float
box to again make the same journey, part passing through the discharge pipe
to the next effect. The steam enters by the pipe g, passes inside the tubes,
the condensed water flowing down and being trapped at », whence it passes on

FIG. 170.

to the next effect, the evaporated vapour passing by way of h to the following
body. The Lillie evaporator differs from others in the following points. The
juice under evaporation is always in a state of film or rain, and hence there is
no tendency for the boiling point to be elevated through the pressure of a
column of liquid and thus to diminish the efficiency of the heating surface.
The quantity of juice in process of evaporation at one time is very small and
is consequently under treatment but a short time. The state of subdivision
of the juice allows a free and easy disengagement of vapour without spurting
and tends to diminish entrainment losses.

300

THE EVAPORATION OF THE JUICE TO SYRUP.

The Kestner Evaporator. — This type of evaporator is radically
distinct from all the forms previously described, and is the last development of
the principle of l ruisellement' or ' grimpage? It is a vertical tube externally
heated film evaporator, and consists of a vertical tubular calandria, Fig. 171,
with tubes about 23 feet long; the juice under evaporation is contained in the
tank #, and passes by the pipe T to the interior of the tubes, which are from
1-5 to 3 inches in diameter; the heating steam enters the shell at A, and
the formation of vapour within the tubes causes the liquid undergoing the
treatment to climb upwards in the tubes ; at D is shown a centrifugal separator
designed to prevent entrainment.

It is claimed for this apparatus that the
coefficient of transmission of heat is very
great and that owing to the juices being but
a short time under treatment it is especially
adapted to be used as the pre-evaporator in
the Pauly-Greiner scheme of heat utilization
described below.

Van Trooyen4 gives the following
particulars of a Kestner quadruple at
' Pasto-Viejo,' Porto Rico. Each body
is a vertical cylinder 24 feet high and
3 feet 6 inches in diameter, made in two
pieces with an expansion joint ; the separ-
ating chamber is 7 feet in diameter and
6 feet high, except in the last body where
it is seven feet high. The heating surface
in the first three vessels consists of 250
tubes, 23 feet long and 1^ inches outside
diameter; in the fourth vessel there are 130
tubes, also 23 feet long and 2f inches
diameter. The heating surface in the whole
apparatus is 8141 square feet. The pumps
are of the following dimensions : —

FIG. 171

Stroke .. ..
Steam cylinder
Pump cylinder
Revolutions

Air.
Inches.

20f

23
46

Juice.
Inches.

Water.
Inches.

10f
12J

The syrup is removed from the last body by means of a barometric
fall pipe.

301

CANE SUGAR.

Witcowitz Heater. — In Fig. 172 is shown in section the radiating
heater of "Witcowitz. It consists of a forged steel body, aa, through which
pass at right angles to each other a series of tubes, bb. The juice circulates
through these tubes, the heating steam being without the tubes and within
the steel body ; the condensed water and heavier gases are drawn off at c, the
lighter ammonia cal gas at d. A very rapid circulation is claimed for this
design ; it is usually applied to the horizontal form of evaporator described
above, and is also used as a heater in saturation and defecating tanks, and is
capable of application to the vertical form of evaporator.

Express System.5 — Another modification of the heating surface,
known as the 'Express' system, is shown in section in Fig. 178. It consists
of a belt, aa, in which are arranged the tubes which form the heating
surface ; as in the Witcowitz heater above described, the juice circulates
through the tubes b, steam entering
the collector box at c, and the con-
densed water passing away at d.
The collector box is set at an angle
following the slope of the saucer
of the effect, usually at an angle
of about 30° from the horizontal;
the tubes are about 18 inches long.
In an effect entirely on this system
there will be a second calandria
above the one shown and placed in
regard to it as a mirror image to
the object. This design can be
readily applied to effects with the
ordinary vertical tube calandria, a
belt being added to the effect below Fm- I72t

the existing calandria in which the additional heating surface is placed.

The ' Express ' system has been further developed by placing within the
shell of a vessel an inner shell of the same diameter as the calandria and
leaving a space of some inches between the two walls ; a colder and heavier
liquor collects here, which tends to descend and thus to form an induced
circulation.

Incondensible Gases. — In the process of evaporation a certain
quantity of incondensible gas is formed, and in addition some air enters with
the steam and through leaks in the apparatus. These gases have a corroding
effect on the apparatus, and if allowed to accumulate seriously diminish the
efficiency of the heating surface. In the first vessel they may be removed by
a cock opening into the atmosphere, but as steam also will pass out, this
process is uneconomical, and it is preferable to pass the gases successively

302

THE EVAPORATION OF THE JUICE TO SYRUP.

from vessel to vessel and finally to the condenser of the pump. The pipe
collecting the gases should be placed as remote as possible from the steam or
vapour inlet ; it is quite usual to find the gases collected in three or four
places, the several pipes afterwards uniting into one. The pipes collecting
the gases should be arranged flush with the top tube plate, and should not
project beneath it, else opportunity will be given for the gases to accumulate.

Condensed Water. — The condensed water from the first vessel is
used in the boilers, and there being a pressure in the calandria of the first
vessel it does not require to be drawn off by a pump, but may be passed
through a steam trap. The condensed water from the second and subsequent
vessels must be drawn off by a pump, and its rapid evacuation has a con-
siderable elfect on the efficiency of the apparatus. This water is not suitable
for use in boilers, and is generally employed in maceration. A small heat

FIG. 173.

economy is obtained by passing the condensed water of the second vessel
through the calandrias of the third and subsequent vessels. In certain
instances a pump for drawing off the condensed water is dispensed with, the
water being trapped and passed into the main pump ; this scheme is not to be
recommended, both on account of diminishing the efficiency of the pump, and
also as losing a valuable supply of hot water.

Distribution of Steam in the Calandria.— The earlier types
of apparatus were provided with only one pipe for carrying steam to the
calandria, resulting in an uneven distribution of steam ; the later apparatuses-
distribute the steam by any of the following devices : —

(a) The arrangement of baffles in the calandria causing the steam to
follow a zig-zag course ; these baffles may be horizontal or vertical ; in one
design a baffle following a helical course is used, the steam entering at the side
and being conducted to the centre of the vessel.

303

CANE SUGAR.

(b) A steam belt completely encircling the calandria.

(c) Division of the main steam or vapour pipe into two or more branches,
which may lie in the same horizontal or vertical plane, or four branches may
be used, two in the same horizontal and two in the same vertical plane.

(d) The use of an internal vapour pipe passing down through the lead
box of a vessel and connecting with the calandria at the position often
occupied by the central juice circulating tube ; in this design an annular space
is arranged between the calandria and the shell of the vessel.

Circulation of the Juice.* — The circulation in an evaporator may
be either positive or induced ; the former when the circulation is obtained by
means of pumps withdrawing juice from and returning it to a vessel and
the latter when the circulation is obtained by the skill of the designer. In
the earlier evaporators the central circulating tube (shown in Fig. 158) was
absent and circulation too was restricted;
the addition of this tube probably acts
in the following way. Owing to the
absence of heating surface the juice
therein contained is cooler than that
in the tubular cluster and tends to
sink ; its place is taken by hotter j uice
from the tubes and a regular circulation
from centre towards the periphery is
induced. In some apparatus the tube is
placed at the side remote from the
steam entry and it may be replaced
by a space formed by cutting away a
segment of the calandria on the side
remote from the steam entry. The
circulation so induced may be aided by
asymmetry in the design of the shell ;
thus the saucer instead of sloping equally in all directions may be bellied
on one side.

The utilization of temperature difference to induce a circulation has been
further developed by the combined use of live and of exhaust steam; in
Heckman's circulator, Fig. 17!j., a small tubular cluster is arranged without,
"but connected to, the main calandria, and is heated with live steam; in
Rohrig's and Konig's design live steam is also used, the calandria taking the
form of a small annular cluster arranged symmetrically with the vertical axis
of a vessel.

* Just before sending his MSS. to the press the author read Prof. Perry's The Steam Engine;
in Chap. XXXIII. (edition of 1907), entitled "How Fluids give up Heat and Momentum," he
discusses the importance of circulation of both hot gases and water as affecting the efficiency
of the boiler: between the evaporator and the boiler there is a difference of degree only;
his remarks on boilers are equally applicable to evaporators and should be studied carefully
.by all sugar house engineers.

304

Fm. 174.

THE EVAPORATION OF THE JUICE TO SYRUP.

Ruissellement. — By this term is meant the evaporation of juices in
films as opposed to evaporation in bulk. It will be shown later that a high
level of the juice undergoing evaporation is not conducive to a high efficiency,
and further in bulk evaporation the body of juice under treatment at one time
is great and may represent up to two hours' output of the mills. To overcome
this disadvantage of the vertical tube apparatus many appendages to and
various forms of tubes have been invented with the object of maintaining a
film of liquid on the interior of the tubes. None of these devices have come
into permanent use, as from their nature they prevented the cleaning of the

FIG. 175.

tubes. Ruissellement^ or film evaporation, has, however, been successfully
.applied in the Yaryan, Lillie, and Kestner designs, and has been adapted to
the vertical tube apparatus in the Meyer and Arbuckle patent ; this process is
shown schematically in Fig. 175. The circulation of the juice is effected by
the centrifugal pumps; the juice on entering the pipe emerges as a
spray through perforations in the latter and at the same time causes the pipe
to revolve in a horizontal plane ; the action is exactly similar to the sprinklers
•commonly used in watering lawns.

Film evaporation may to a certain extent be obtained in vertical tube
apparatuses by keeping the level of the juice one-third to one-half the height

305

20

CANE SUGAE.

of the level of the upper tube plate ; the contained juice creeps up the sides
of the tuhes, and in this form permits a rapid exchange of heat. Claassen's
observations give the following coefficients of transmission : —

Tubes full ..'.... ,.. .. .. . 2-50

Tubes two-thirds full . . 3'00

Tubes one-third full . . . . 3'60

Euissellement 2'90

Entrainment. — By entrainment is meant the carrying over of sugar
along with the vapours and its consequent loss. Entrainment may take place
in two distinct ways : in the first case the loss is entirely mechanical, and is
due to splashing following on a vigorous ebullition, particles of juice being
projected into the vapour pipe of the vessel. In the second case, loss is caused
by vescicular transference ; by this term is meant the formation of bubbles of
liquid, which being very light in proportion to their bulk are readily earned
forward with the stream of vapour.

FIG. 176.

The first cause of entrainment is capable of control ; the more vigorous
the ebullition the greater is the height to which particles of juice will be
projected ; with vessels having tubes of great length bubbles of steam formed
at the lower layers will burst with greater force on reaching the vapour space
than where the tubes are shorter ; further, tubes of short length imply vessels
of large diameter and consequently a less velocity to the current of vapours
moving forward to the next vessel. Losses due to splashing may be entirely
prevented by the use of bafflps, and better still by an amplo vapour space.

The best known contrivance to prevent loss in vescicular transference is
the Hodek Ralentisseur, Fig. 176, very extensively used in the beet sugar
industry, but not often found in cane sugar factories, the island of Mauritius
being an exception, and upon which many other designs have been based.
The Hodek Ralentisseur consists of a vessel of considerably greater diameter
than the vapour pipe, and of length generally about twice its diameter; it is

306

THE EVAPORATION OF THE JUICE TO SYRUP.

interposed in the vapour pipe connecting any two bodies, and is placed in
either a horizontal or vertical position ; placed in the vessel are perforated
diaphragms, generally three in number, the sum area of the perforations
being greater than the area of the vapour pipe ; the diaphragms are sometimes
dispensed with. Horsin Deon6 states that as the most appropriate dimensions
the Ralentisseur should be 3-5 times the diameter of the vapour pipe, and that
the length should be twice the diameter.

The action of this apparatus is two-fold ; the sudden increase in area of
the pipe decreases the pressure of the vapour, so that the external pressure on
the bubble is diminished and the latter bursts ; in addition, there is the effect
of the shock the bubbles suffer on striking on the walls of the diaphragms.

A sudden change in direction has also been observed to diminish entrain-
ment losses, and vapour pipes are sometimes supplied with an enlarged section
in which the direction of the vapour is twice abruptly changed by means of
baffle plates.

A second form of entrainment preventer, the patent of Messrs. John
McNeil & Co., is shown in Fig. 177. Within the dome-shaped cover a of the

FIG. 177.

effect or pan is arranged a conical vessel 1. The orifice of this funnel is-
pointed in the direction opposite to the pipe leading to the next effect or to
the condenser. Particles of juice are projected on to the roof and thence fall
on to the sides of the cone, and the vapour in its passage round the cone also
deposits particles of liquid. The condenser pipe c projects inwards to prevent
these particles from being swept forward with the current of vapour.

In the factories with which the writer has been connected entrainment
losses were so small that it was practically impossible to estimate them, and
it was only in waste water from the last vessel of the evaporator that sugar
could be detected, and then not by any means always.

Fries7 in Hawaii ingeniously placed small pipes in the vapour pipes of
the effects and pans and measured the sugar there collected over definite
periods ; he found a loss of -006 per cent, in the pans, and a variable loss of
•002 per cent, to -008 per cent, in the evaporators.

307

CANE SUGAR.

The writer has found, however, in evaporators of old design, with small
vapour spaces and pipes of restricted area, losses amounting to 2 per cent, of
the sugar entering the boiling house.

Theory of Multiple Evaporation.— The theory of multiple
evaporation in vacuo has been elaborated by Jelinek, Horsin-Deon, Dessin,
Claassen, Bolk, and Hausbrand; the most complete and elegant theory is that
due to Hausbrand8; in what follows, the writer is indebted to all these
experts, and especially to the last mentioned.

It may be stated at once that it is impossible to calculate OD first princi-
ples the pounds of water evaporated in each body of a multiple effect, unless
the different temperatures in each body are assumed. The temperatures,
however, depend on a number of factors — the temperature of the heating
steam, the vacuum in the last body, the height of the liquid under treat-
ment, &c., all of which are variable or unknown. Very considerable informa-
tion can, however, be obtained on the lines below.

In a simple unexact way it is understood that a pound of steam introduced
into the first body evaporates there a pound of water, the resulting steam
passing on to the second body again evaporates a second pound of water and
so on ; but this supposition is only approximate.*

In the first instance, as the temperature at which evaporation occurs
decreases, the latent heat increases, so that for this reason the steam from an
earlier vessel evaporates less than its own weight of water in the succeeding
one, but on the other hand the liquid entering from an earlier vessel itself
suffers a fall in temperature and the heat given up can go only towards the
formation of steam. Water evaporated by reason of this last cause is termed
self-evaporation. As a numerical example the following data may be taken :
100 units of water enter the first vessel and from it are evaporated 25 units of
water, so that 75 units pass on to. the next vessel. Let the temperature in the
first vessel be 212° F. and in the second vessel be 194° P. ; the latent heats
of steam at the two temperatures are 966 and 978 B.T.U. respectively. The

Q A f\

25 units of steam will then evaporate by their condensation 25 X — =- = 24-7

y / o

units of water. But the water in cooling down from 212° F. to 194°F. gives
up 75 (212 — 194) = 1350 units of heat ; this quantity will evaporate

1350

— — = 1-4 units of water. This latter is the self-evaporation and the total
y /o

evaporation is 24-7 -f 1-4 = 26-1 units. Another cause tends to make the

* It should be pointed out that the evaporation in a multiple evaporator is best expressed
as water evaporated per Ib. of steam received + steam used in driving the vacuum pump ;
actually most of the direct steam admitted to the cylinder of the pump passes out as exhaust,
the heat of which is utilized in evaporation, but the steam condensed in the cylinder + that
represented by the fall in total heat of the portion which passes out, should be added to the
steam condensed in the calandria of the first effect when estimating the evaporation per Ib. of
steam. Since a quadruple of equal capacity with a triple will require a smaller pump, the
economy of the former compared with the latter will tend to be greater than in the ratio 4 : 3.

308

THE EVAPORATION OF THE JUICE TO SYRUP.

evaporation greater ; the steam or vapour which has induced evaporation flows
away, not at the temperature which it possessed when in the form of steam,
but at the temperature which prevails in the lower part of the calandria where
it is condensed ; however the evaporation on this score is barely appreciable.

By a system of trial and error, Hausbrand has calculated the actual
evaporation in each vessel of a double, triple, and quadruple effect for a large
number of differently divided temperatures, for evaporations 90 per cent, and
75 per cent, of the original weight of the liquid, and from the results of his
calculations he has demonstrated that of the total quantity of water evaporated
in any vessel, that portion evaporated by heating (apart from self-evaporation)
is very constant, and that the total evaporation in any such vessel is very much
of the same order.

The five conclusions drawn by Hausbrand are : —

1. The smallest amount of heating steam required to produce a certain
amount of evaporation is used in all evaporators when the fall in temperature
is the same in each vessel.

2. However the fall in temperature in the separate vessels be arranged,
the weight of heating steam to be supplied to the first vessel varies always
within very narrow limits. Thus the manner in which the available fall in
temperature is distributed amongst the separate vessels has no great influence
upon the economy of steam. No considerable saving in stearn can be obtained
by any definite division of this fall in temperature.

3. The quantity of water to be evaporated in the first vessel is on an
average of the total evaporation : —

In the double effect ^-^ = 0-466.

In the triple effect — ^— = 0-300.
3*333

In the quadruple effect -rV~ = 0-216.
The extreme cases are : —

For the double effect 0-434 - 0-484.
For the triple effect 0-2777 - 0-3152.
For the quadruple effect 0-1926 — 0-2335.

4. The evaporation effected by heating* is in all cases the least in the
first body, but the increase in the following vessels is not very great, at most
4 per cent. In the mean it may be assumed that this evaporation in the
separate vessels is in the

Double effect 1 : 1'045.

Triple effect 1 : I'Ol : 1-04.

Quadruple effect 1 : 1'005 : 1-012 : 1'02.

* Steam produced by self-evaporation in the second body evaporates water by heating in
the third ; these figures do not include water evaporated by heating on this score.

309

CANE SUGAR.

5. The total quantity evaporated in the last vessel is
In the double effect 0-534.
In the triple effect 0-3734.
In the quadruple effect 0-284
of the total evaporation of the apparatus.

In the mean the evaporative capacity of each vessel, not including self-
evaporation in the vessel, but including the evaporation due to heating from
self-evaporation in a previous vessel, is in
Double effect 1 : 1-0045
Triple effect 1 : 1-0075 : 1-138.
Quadruple effect 1 : 1-0055 : 1-109 : 1-196.

Hausbrand uses the figures given immediately above to calculate the
relative areas of heating surface in the different vessels, provided the coefficient
of transmission of heat is known in each vessel ; if, for the moment, this be
taken as the same for each vessel, then if equal differences of temperature are
desired from vessel to vessel, this would be obtained by making the heating
surfaces in the ratio given above ; similarly, if the heating surfaces were made
the same in all the vessels the falls in temperature would be in the same ratio.
The transmission of heat is, however, not the same for all the vessels ; it
decreases from vessel to vessel, due to the greater viscosity and to the incrus-
tations being more pronounced in the later vessels.

Claassen, from actual observations in beet sugar factories, gives the
following ratios for the transmission coefficient : —

Vessel. I. II. III. IV.

Double effect ........ 1 : 0'66

Triple „ .......... 1 : 0'70 : 0'33

Quadruple effect ....... 1 : 0'91 : 0'75 : 0'55

If these figures be taken as data, then to obtain the same temperature
difference, the heating surfaces would be in the ratio : —
Double effect —

Triple effect—

Quadruple effect —

• • .- • «• , »»

.....

Now since it is only by larger differences in temperature that viscid juices
are brought into violent ebullition, and since it is of great importance to main-
tain a rapid movement and good circulation, it is better, says Hausbrand, to
have a large fall in temperature between the two last bodies, and not to aim at
equalizing the fall in lemperature by increasing the heating surface in the later
bodies.

310

THE EVAPOEATION OF THE JUICE TO SYRUP.

It was, and still is, a very general rule for makers to design evaporators
with heating surface increasing from vessel to vessel. Hausbrand recommends
that at the very most the heating surface in the last body should be not greater
than and perhaps a little smaller than in the first.

The Efficiency of a Multiple Effect. — A very important
factor in dealing with multiple effects is the evaporation per square foot of
heating surface, or, in other words, the capacity ; the chief factor is the
available fall in temperature from vessel to vessel. A numerical example,
which is founded on the methods used by Dessin9, will show how this fall
is controlled.

Let the heating steam be at a pressure of 8 Ibs. per square inch, cor-
responding to a temperature of 234° F., and let the pressure in the last body
be 2*42 Ibs. per square inch, corresponding to a vacuum of 25 inches, and to a
temperature of 132°F.

Then the total fall in temperature is 234 - 132 — 102°F., and the
average fall from vessel to vessel is 34° F. Let the juice under treatment
enter at a density of 1-0709 or 18° Brix, and leave at a density of 1-253 or
55° Brix.

Now for convenience of calculation let there be equal evaporation* in
each vessel, then the total evaporation per cent, by weight on original juice is

55 _ 10

— — — x 100 = 67/27 per cent.
oo

of which each vessel evaporates one-third or 22-42 per cent, of the juice.
Then if B. is the degree Brix of juice in the first vessel

whence B. = 23-2, corresponding to a density of 1 '093. Similarly the juice
in the second vessel is found to be of density 32'6 Brix or 1-136.

These densities are correct at a temperature of 84° F., and the densities
are required at the temperatures prevailing in the vessels which, assuming the
fall in temperature equally divided, are 210° F., 180° F., 160° F. ; the
respective densities at these temperatures are 1-054, 1*106, 1-229.

Now consider the case of a vertical submerged tube apparatus with tubes
4 feet long, and let the level of the liquid be 6 inches above the level of the
tube plate ; the vapour formed in the tubes must, so as to disengage itself, be
at a pressure equal to the pressure in the vapour space increased by the
pressure due to the weight of the column of liquid. This increase in pressure
varies with the place where the vapour is formed ; the maximum height is
4 feet, the minimum 6 inches, the mean is 27 inches.

* The results obtained by Hausbrand show that this condition can never obtain ; this
section is introduced to explain certain important principles in the multiple evaporator,
and an ideal case is chosen for simplicity ; the application of the conclusions is in no wise
invalidated.

311

CANE SUGAR.

Then since the vapour at the moment of its formation is at a greater
pressure than that already formed, and since the temperature of a boiling
liquid is equal to that of the vapour which it gives off, it follows that the
mean temperature of the juice in ebullition is greater than that of the vapour
in the vapour space.

Again, the juice is emulsioned with the vapour it gives off and this has
a tendency to diminish the density of the boiling juice. Now to obtain an
idea of the volume of the contained vapour, Dessin recalls the phenomenon
observed when an evaporator stops boiling, namely, that the level of the
liquid falls. This fall in level, which is 3 inches in extent, Dessin takes as
giving the volume of the contained vapour.

Take the case of the third body of a triple, the vacuum being 25 inches,
the vessel 6 feet internal diameter, the tubes 4 feet long, 2 inches diameter,
and 630 in number. The total volume of the juice is the volume of the
tubes -f- the volume above the tube plate — the volume occupied by the vapour.

We have, then, at rest

c.ft.
Yol. of the tubes = 630 TT (TV x TV X 4) c. ft. = 55-0

Vol. above tube plate = TT x 3 X 3 x £ c. ft. = 14-1

69-1
During ebullition the total volume is that found above + that occupied

by vapour = TT x 3 x 3 X i c. ft. = 7'0 c. ft. The total volume during

ebullition is then 76-1 c. ft.

The finally corrected densities of the juices then appear

First vessel, 1-054 X-^~T= '957
76'1

Second vessel, 1-106 x-= = 1*004

76-l

69*1

Third vessel, 1-229 x-r7r-r-= 1-116
7o*l

The vapour then in the third vessel will have to raise a column of liquid of
mean height 27 inches, and of density 1-116 ; this is equivalent to 2'20 inches
of mercury or 1-09 Ibs. per square inch. The vapour itself was taken at a
pressure of 2-42 Ibs. per square inch, so that the pressure of the vapour at the
moment of its formation is 2'42 -f 1-09 = 3 51 Ibs. per square inch, corres-
ponding to a temperature of 147° F. ; that of the vapour was 132° F., a
difference of 15°F.

Similarly for the second body a difference of 7° F., and for the first of
4°F. are found.

The efficient fall in temperature from body to body is then
284 - 132 - (15 + 7 + 4) = ^^

3

or 76-5 per cent, of what would be the case if the height of juice in ebullition
was zero.

312

THE EVAPORATION OF THE JUICE TO SYRUP.

To illustrate of what vital importance it is to have as great as possible a
vacuum in the last body, figures are given below for an identical apparatus
where the vacuum in the last body is 27 inches corresponding to a temperature
of 114° P., and a pressure of 1-43 Ibs. per square inch. Taking the vacua in
the other two bodies as 4 inches and 17 inches, the efficient fall in temperature
is found to be 30-3° P., that is to say the heating surface compared with the
apparatus where the vacuum in the last body is only 25 inches, is 30 per
cent, more valuable.

In describing the Welner-Jelinek apparatus it was stated that the height
of the column of liquid was only 24 inches. A calculation as above for a final
25 inch vacuum gives the efficient fall in temperature as 28° F.- 29° P.,
and proportionally higher for a 27 inch vacuum. It was with particular
reference to this point that the Welner-Jelinek was designed.

In the film evaporators of the Lillie and Yaryan type there is no increase
in pressure due to the height of the boiling column of liquid, but whereas in
the latter the juice is contained in the tubes and the vapour formed can only
escape at the end of a unit, this vapour must, while in the tubes, be under
pressure and tend to increase the boiling point to the detriment of the efficiency
of the heating surface. In the Lillie design the vapour formed is free to escape
in all directions, and the juice falling in a rain or film there is no increase of
temperature in the body of the liquid for the reasons detailed above, and the
efficiency of the heating surface must approach the maximum value.

In a quadruple effect submerged vertical tube apparatus the efficient fall
in temperature from vessel to vessel on the lines given above works out with
a 25 inch vacuum at about 14° P., and with 27 inch vacuum at about 18° P. ;
for a Welner-Jelinek the corresponding figures are about 16° P. and 20° P.
The maximum for the two cases, there being no increase due to head of liquid
under treatment, is 25° F. and 30° P. respectively.

In many sugar houses the evaporation is done by triple effects, and it was
supposed once that the maximum working number of effects was three, and
that with four a sufficient fall in temperature could not be obtained to allow
heat to pass from condensed vapour to boiling juice. Formerly vertical
apparatus were constructed with tubes even 6 feet long, causing the efficiency
of the heating surface to become very low. By reducing the length of the
tubes to 3 feet or 3 feet 6 inches, and by attending to the necessity for as low
a vacuum as possible in the last body, quadruple effects using back pressure
steam only are working in many sugar houses, and do not require high
pressure steam at all. In some sugar houses, however, quadruples can be seen
where the juice in the first vessel boils under more than atmospheric pressure.
With film evaporators quadruple evaporation is general, and quintuple effects
have also been constructed. Assuming a minimum fall in temperature for
efficient working from vessel to vessel of 20° F., the maximum number of

313

CANE SUGAR.

effects with steam at 234° F., and a final vacuum of 27 inches, will be six, and
this result could only be obtained with film evaporators.

It should be noticed that this increase in temperature due to height of
liquid is greatest when the pressure is least ; in the following table are given
figures showing how this varies for different pressures, the density of juice
being taken uniformly as unity : —

Mean height of vaL ;uiy<

column of
liquid causing
increase

5

10

15

20

25

27-5

in pressure.
Inches.

Increase in temperature, F°.

12

1

1

2

2

5

9

18

3-5

4

5

5'5

9

18

24

4

5

6

7

13

22

30

4-5

6

7

9

15-5

25

Prom the lines immediately above it may be thought that the lower levels
of juice in an evaporator will be of higher temperature than the upper ; such
indeed is not the case, as was shown by Jelinek, whose observations have been
extended to the vacuum pan by Curin.10

In a well-designed evaporator with a rapid circulation the transfer of heat
from the ' superheated ' particles at the lower levels is very rapid, so much so
as almost altogether to mask the effect of the hydrostatic pressure, so that the
objection to long tubes becomes of diminished importance ; in apparatus with
bad circulation the effect of hydrostatic pressure is very pronounced, and the
low duty of many of the evaporators dating back to the eighties may be
attributed to these causes. Extreme length of tubes, combined with a high
duty, is seen in the Stillman and Kestner apparatus, which utilize the principle
of ' ruissellement ' or * grimpage? best rendered in English as ' creeping' This
principle can be used in bulk evaporators of conventional design, but the type
of labour usually available in the tropics is not to be trusted to use it ;
hence the writer thinks that a bulk evaporator with tubes of a conservative
length with a well-arranged circulation is the best type to adopt.

Conditions are rather different in vacuum pans, and here the effect of the
hydrostatic head is very noticeable; that is to say, it is a matter of clinical
observation that tall narrow pans are much less rapid boilers than are broader
shallower apparatus.

Capacity of Multiples.— A vertical submerged tube triple effect
may be considered as giving a high duty when it evaporates 8 Ibs. of water
per square foot per hour ; a quadruple is satisfactory when it evaporates 6 ; a
Lillie quadruple film evaporator will be satisfactory when it gives a duty of
10 Ibs., or a triple when it reaches 13 Ibs. ; a horizontal tube low level appar-
atus will have a duty lying between these figures, and a ' creeping* vertical tube
apparatus of the * Stillman ' type will approach or equal in duty the film type.

314

THE EVAPORATION OF THE JUICE TO SYRUP.

Increase of the Capacity of a Multiple Effect.— From

what has been written it follows that the capacity of a multiple can be
increased along the following lines : —

1. By keeping the heating surfaces clean. Evaporators are sometimes
constructed with a spare vessel, so that one vessel is always out of use ; the
apparatus can then be cleaned without stopping operations.

2. Increase of the fall of temperature, effected either by increasing the
pressure of the heating steam or by increasing the vacuum in the last body ;
where exhaust steam is used in the first body the increase in pressure is
limited by the demands of the motors, and according to Claassen's dictum
(supra) an increase in the vacuum in the last body over and above 60 cm.
or 23'7 inches is not attended with material benefit.

3. Decrease of the height of the liquid contained in the calandria as
exemplified in the Welner-Jelinek design.

4. By ' ruissellement,' best obtained in a vertical tube apparatus, by
maintaining a low level of juice in the apparatus.

5. By increase in the rapidity of the circulation.

Temperatures in the Multiple. — It has already been shown
that the fall in temperature from vessel to vessel, and consequently the
temperature in each vessel depends on the heating surface in each vessel, and
on the coefficient of transmission of heat in each vessel ; the ratio of heating
surfaces to obtain an equal fall of temperature from vessel to vessel as calcu-
lated by Hausbrand have already been given ; if, then, as is generally the
case, the heating surfaces are equal, the fall of temperature from vessel to
vessel will be in inverse proportion to these ratios.

In the triple the total fall will be divided between the three vessels in
the ratios : —

First Tessel 1 1.44'+ 3-445 = '1698

+ l-44+ 3-445
Third vessel 1 + 1.47^3.445= -5857

If the initial temperature of heating steam be 220° F., and the final
temperature be 130° F , the total fall is 90° F., of which there occurs in the
First vessel, 90 X '1698 = 15-3°F.,
Second vessel, 90 x '2445 = 22-0° F.,
Third vessel, 90 X '5857 = 52-7° F.,
and the temperature prevailing will be

First vessel. Second vessel. Third vessel.

204-7° F. 182-7° F. 130° F.

315

CANE SUGAR.

A similar calculation for the quadruple gives the total fall as divided in
the ratio

•1736 : -1919 : -2569 : -3776

and if, as before, the total fall is 90° F., there occurs in the
First vessel, 90 X '1736 = 15-6° F.,
Second vessel, 90 x "1919 = 17'3°F.,
Third vessel, 90 X '2569 = 23-1° F.,
Fourth vessel, 90 x '3776 =: 34-0° F.,

and the temperatures prevailing will be

First vessel. Second vessel. Third vessel. Fourth vessel.

204-4° F. 187-1° F. 164° F. 130° F.

Extra Steam. — By this term is meant an arrangement in which
steam is taken from an earlier vessel of the evaporator to perform evaporation
or heating in some other part of the factory ; this scheme is also due to
Billieux and has been developed almost exclusively in the beet sugar industry,
where indeed the opportunities for its use are more numerous than in the cane
sugar factory, and where, owing to all the fuel being purchased, every
economy in this department means a direct source of profit.

To demonstrate the economy of this scheme, let there be 100 parts of
juice at 15° Brix, which are to be evaporated to 55° Brix in a triple effect,
and finally to 96° Brix at single effect; then there are removed in all

- X 100 = 84-37 parts water, and in the triple alone — - x 100
96 55

= 72-72 parts water, so that in the pan there are removed 11-65 parts water;
the evaporation in the triple is equivalent to the removal of 24'24 parts
water at single effect, so that the total consumption of steam is proportional
to 24-24 + 11-65 = 35-89 parts water per 100 of juice.

Now let the arrangements be changed so that the steam necessary for pan
evaporation is taken from the first vessel of the triple ; thus evidently both
the heating surface of and the evaporators in the first vessel must be increased
since this vessel has to supply steam for the second vessel and for the pan.
Let the evaporation in either of the last two vessels be a ; then in the first
vessel the evaporator is a -\- '1165*; whence it follows that

30 + -1165 — -7272
a — -2036

i.e., the first vessel must evaporate 11 '65 + 20-36 = 32-01 parts water per
100 of juice, and of this quantity 20-36 parts go on to the second vessel and
11*65 parts go on to the pan ; this quantity is the equivalent evaporation at
single effect, where as previously it was 35-89.

* This assumes equal evaporation in each vessel, a result which does not happen, but
the differences do not affect the present reasoning.

316

THE EVAPORATION OF THE JUICE TO SYRUP.

Instead of taking steam from the first vessel of an evaporator it may be
taken from a later one, and a still greater economy effected ; let steam be
taken for use in the pan from the second vessel of a triple ; thus if a be the
evaporation in the last vessel of the triple,

3a -f -1165 + -1165 = -7272
whence a = '1647

that is to say, the evaporation in the first and second vessel is 16-47 + 11-65
= 28-12, and this quantity is the equivalent evaporation at single effect;
other combinations might be the taking of extra steam from both first and
second vessels of a triple or quadruple, but as in the second vessel the
temperature of the steam is already low, it does not seem there would ever be
much opportunity in a cane sugar factory to take steam other than from the
first vessel ; in a beet sugar factory opportunity arises at the diffusion and
carbonation stations.

FIG. 178.

This method of evaporation is shown diagram matically in Fig. 178 ,
where al a2 a3 is the triple, the first vessel having an enlarged heating
surface, so as to provide steam for the pan b and the heater c. Any scheme
as the above requires an entire redistribution of the heating surfaces in the
evaporative plant. Suppose in a certain factory there is a triple with 2000
square feet heating surface in each vessel and it is desired to alter the arrange-
ments and boil the pan with steam from the first vessel, the output of the
factory remaining unaltered ; then using the data established above, the

O (\ • *^ A

heating surface in either the second or third vessel will be 2000 X

or 1680 square feet, and in the first vessel it will be 1680 x
square feet.

317

32-01
20-36

24-24
= 2140

CANE SUGAK.

It is however in the pan that the greatest change is made, for although
the amount of work done here is unaltered it is now done with steam, at say,
a temperature of 210° F. whereas previously the temperature may have heen
260° F ; taking an average temperature in the pan of 160° F. the temperature
differences are 100°F. and 50° F., so that at least double the amount of pan
heating surface will be required.

The Pre-evaporator. — The very large heating surfaces required
with the use of extra steam have led to the introduction of the Pauly ' pre-
evaporator/ This consists of a vessel independent of the evaporator proper
and receiving steam at a pressure of about 30 Ibs. ; the juice is partly concen-
trated herein and the vapour given off which may be at a pressure of about
15 Ibs. per square inch goes to the heaters and pans ; the partly concentrated
juice passes on to the evaporator which is heated by exhaust steam from the
engines; in the pre-evaporator the transmission of heat is high and compara-
tively small heating surfaces are required. In beet factories it has been
established that no appreciable loss of sugar due to the high temperature
boiling need obtain. In this scheme there seems great opportunity for the
use of the ' Kestner ' as a pre-evaporator, as in this type the juices are the
minimum time under treatment. This scheme modified by Greiner and known
as the Pauly-Greiner is shown in Fig. 179 ; in this arrangement two sets of
boilers are used, one, a, supplying high pressure steam to the engine b, the
exhaust from which passes to the first vessel of the evaporator c ; the other
set of boilers a1 supply steam at 30 Ibs. to the pre-evaporator d which in turn
supplies the pan e and heater /. Connections are usually established so that
the pre-heater and quadruple may, if desired at any time, work as a
quintuple.

The relative economy of some of the different possible combinations is
calculated and tabulated below; in making these calculations the following
data are assumed : — 100 parts of juice at 15° Brix, of temperature 82° F., of
specific heat *9, are heated to 212° F. ; this juice is evaporated to 55° Brix in
the multiple and finally to 96° Brix in the pans ; hence 72-72 per cent, of the
juice is removed in the multiple and 11 '65 per cent, in the pans. The con-
sumption of heat in the heater is 100 x (212 — 82) X '9 = 11,700 units,
and taking the latent heat of steam as 970 this is equivalent to the evapora-
tion at single effect of 12'06 parts of water. At triple effect the evaporation
is equivalent to the removal of 24 -24 parts water at single effect, so that the
number 12-06 -f 24'24 + 11 -65 =± 47'95 is proportional to the heat or steam
consumption with this method of working. Now let all the steam required
for the pans be taken from the first vessel of the triple; then, as already
shown above, 32-01 parts of steam must be there delivered, and the total
consumption of heat or steam is proportional to 32*01 -|- 12-06 or 44*07,

318

THE EVAPORATION OF THE JUICE TO SYRUP.

319

CANE SUGAR.

i.e., 91 91 per cent, of that required with conventional triple effect
evaporation. Results of similar calculations are tabulated below : —

Relative

Consumption

of Steam.

Conventional triple evaporation 100 -00

Conventional quadruple evaporation 87 '28

Triple evaporation and extra steam to pan 91 '91

Pre-evaporator to pan, and triple 91*91

Triple evaporation and extra steam to heater 91*62

Pre-evaporator to heater, and triple 91 '62

Triple evaporation and extra steam to pan and heater . . 83*46

Pre-evaporator to pan and heater, and triple 83*46

Quadruple evaporation and extra steam to pan 81*32

Pre-evaporator to pan, and quadruple 81*32

Quadruple evaporation and extra steam to heater . . . . 80*52

Pre-evaporator to heater, and quadruple ...... ... 80*52

Quadruple evaporation and extra steam to pan and heater. . 75*00

Pre-evaporator to pan and heater and quadruple 75*00

In addition combinations of the pre-evaporator with extra steam from
the multiple can be devised.

The Picard System. — This method has never, the writer believes,
been applied in any sugar factory, although it has been working in other
manufacturing processes since 1878. In this scheme part of the vapours given
off from the first vessel are drawn off into a compressor and raised to a high
pressure ; their temperature is thereby increased, and on again being introduced
into the calandria of the effect are capable of evaporating a further quantity of
water. This scheme can of course be worked to its best advantage where
power, as from a fall of water, is available to drive the compressor. This
method was described in 1880 by P. 0. Whitehead,11 and its mathematics
have been discussed in detail by Svorcik,12 who as a final result lays down that
in a triple with this scheme one part of steam will evaporate altogether 4*248
parts of water. His idea of the regeneration of vapours has been made
practical by Selwig and Lange, who have put into practice the scheme of
withdrawing part of the vapour from the penultimate vessel of a multiple by
the use of live steam injectors, and returning them either to an earlier vessel
-or utilizing them in heating or in the pans.

Calculation of Heating Surfaces. — When the amount of heat
necessary to be transmitted, the difference of temperature between the juice
to be heated or juice to be evaporated, and heating steam are known, the
requisite surface can be calculated by means of the coefficients of transmission
-already quoted.

320

THE EVAPORATION OF THE JUICE TO SYRUP.

When juices are to be heated the temperature of the juice is taken as the
mean of its initial and final temperature; when the juices are to be evaporated
the temperature of the juice is taken as the mean temperature of the boiling
mass. As an example, let there be 30 metric tons of juice to be heated in one
hour from 30° C. to 100° C., with steam at 105° C. The average temperature

of the juice to be heated is 30° -f 10° — 30 — 65° C. The difference of

temperature is 105° — 65° = 40° C. Taking the specific heat of juice as -9,
the heat to be transmitted is 30,000 X "9 x (100 — 30 J = 1,890,000 calories.

The coefficient of transmission for diffusion, &c., juices is 5, i.e., per
square metre per minute per 1° C. difference of temperature, 5 calories are
transmitted.

Then per hour under the conditions named 1 square metre will transmit
5 x 40 X 60 = 12,000 calories, and the heating surface required is
1,890,000 -j- 12,000 = 157 square metres, or 1689 square feet.

Calculations for pans and evaporators may be made on exactly similar
lines, using the coefficients of heat transmission given in a preceding section.

Dimensions of Steam and Vapour Piping. — The passage
of vapour from the vapour space of one body to the steam drum of the next
takes place under a slight difference of pressure ; this pressure amounts to
0-3 Ib. per square inch, corresponding to a difference in temperature of about
1° F. To calculate from these data the velocity of a gas leaving an orifice
requires the use of higher mathematics, which would serve no useful
purpose to reproduce here ; under the conditions named, the velocity of a gas
is of the order 200 feet per second ; such a velocity is not obtained in
evaporators because of the friction of the gas on the walls of the pipes, abrupt
changes in direction, especially those due to baffle plates and save-alls, and
also to condensation of a part of the vapour. For steam and vapour pipes it i 6
is customary to allow a velocity of 100 feet per second, and for the vapour
leaving the last body a velocity of 150 feet per second; if velocities higher ^*
than these obtain, a very considerable fall in the temperature of the vapour
occurs, reducing the efficiency of the apparatus. As an example of this and
other calculations, the case of a triple effect with 4000 square feet heating
surface, evaporating 6 Ibs. water per square foot per hour, or 2'22lbs. per
second per vessel, is taken.

Steam Pipe. — Taking the temperature of the heating steam to be 234° F.,
1 Ib. will occupy 17-83 cubic feet, and allowing 1 Ib. steam to evaporate
2-90 Ibs. water, 2-31 Ibs. (= 41-19 cubic feet) will be required per second.
At a velocity of 100 feet per second the area of the pipe must be -4119 square
feet, corresponding to a diameter of 8£ inches.

321

21

CANE SUGAR.

Vapour Pipes. — Taking the temperature of the vapour from the first
vessels as 206° F., 1 Ib. occupies 29-6 cubic feet; at a velocity of 100 feet per
second, the area of the pipe must be '657 square feet, corresponding to a
diameter of 1 1 inches. The temperature of the vapour from the second vessel
being taken as 177° F. will occupy 53*4 cubic feet per Ib., and under the same
velocity demands a vapour pipe 1 5 inches in diameter. Finally, for the pipe
leading to the condenser, allowing here a velocity of 150 feet per second, a
diameter of 21 inches is obtained; 1 Ib. of vapour at 132° F. occupying
152 '4 cubic feet.

Injection Water. — Assuming the vacuum in the condenser is
27*5 inches, the corresponding temperature is 104° F., and the temperature of
vapour given off in the last body may be taken as 134° F. At this temperature
the latent heat of steam is 1022 B.T.U., so that in condensing 1 Ib. of vapour
at 134° F. and cooling to 104° F. (corresponding to a vacuum of 27'5 inches)
1052 B.T.TJ. are absorbed. Allowing the injection water to be of tempera-
ture 84° F., each pound of water absorbs 20 B.T.TJ., so that 52-6 Ibs. water
per pound of vapour will be required, and to obtain this result at least
10 per cent, or 20 per cent, more water must be admitted.

It is, however, only in exceptional cases that so large an amount of
injection water is admitted, and the temperature of the discharge is more
frequently 115°F. to 120°F. If the temperature of injection water be again
taken as 84° F., to obtain discharge water at this temperature, the quantity of
injection water required is only thirty times as much as the vapour to be
condensed, and this is the quantity usually allowed for in design. The
objection to admitting the larger quantities is the accompanying increase in
size of the pump, but the economy is only effected at the expense of the
vacuum in the last body, and consequently of the efficiency of the heating
surface as a whole. ,

The size of the injection pipe to deliver a definite quantity of water
depends on the head, the length, and diameter of the pipe, and the number of
bends. The theory of the flow of water in pipes is too complex to be
reproduced here, but a table is given below showing the velocity of water at
exit from pipes of diameter 4 inches to 12 inches, for lengths of from 40 feet
to 100 feet, and with one, two, or three right angle bends. The table has
been calculated from the latest formulae ; a constant head of 1 6 feet has
been assumed corresponding to a 25 inch vacuum, and a height of 12 feet of
entry of injection water above level in well.

322

THE EVAPORATION OF THE JUICE TO SYRUP.

Table giving Velocity of Water at Exit under a Head of 16 feet for
different Conditions of Pipe.

No.
of
Bends.

Length
of
Pipe.

Feet.

DIAMETER OP PIPE. INCHES.

4

5

6

7

8

9

10

11

12

VELOCITY OF FLOW AT EXIT: FEET PER SECOND.

1

40

13-9

15-0

15-8

16-3

16-9

17-3

17-6

17-9

18-1

2

40

13-7

14-7

15-5

16-0

16-5

16-9

17-3

17-5

17-6

3

40

13-5

14-5

15-2

15-7

16-2

16-5

16-7

17'1

17-3

1

60

12-3

13-4

14-4

14-9

15-7

16-0

16-4

16-7

16-9

2

60

12-1

13-2

14-0

14-6

15-4

15-7

16-0

16-3

16-5

3

60

12-0

13-0

13-8

14-3

15-1

15-4

15-7

16-0

16-3

1

80

11-2

12-2

13-1

13-7

14-4

15-0

15-4

15-7

16-0

2

80

11-0

12-1

12-9

13-5

14-1

14-7

15-1

15-4

15-7

3

80

10-9

11-9

12-8

13-4

14-0

14-3

14-7

15-1

15-4

1

100

10-2

10-6

11-5

12-1

12-9

13-4

13-7

13-9

14-4

2

100

10-1

10-5

11-4

12-0

12-8

13-1

13-5

13-7

14-2

3

100

10-0

10-4

11-3

11-9

12-7

12-9

13-4

13-6

14-1

The calculation of the volume of gases removed by the pump is sa
unsatisfactory as not to repay study. A certain quantity of air enters the
apparatus dissolved in the juice, which is released on boiling, and the juice
itself in treatment forms a certain amount of gas ; air, too, will leak into the
apparatus, and some will be introduced dissolved in the injection water.
Experimental data are so incomplete on these points that they can give little
or no help to practice.

LOSS of Heat in Evaporators.— In a naked quadruple standard
evaporator let the temperatures in the vessels be

i.
212

II.
203

ill.
187

rv.
140

With external air at 82° P.

the excess temperature is 130 121 105 58

Interpolating from the table given in Chapter XIX. the heat losses per

square foot per hour are

B.T.TJ.

I. II. III. IV.

336 308 252 126

Let the area of shell and vapour pipes be * 2 of the total heating surface,
then each vessel exposes an area '05 of the total heating surface, and the
losses per hour per square foot of heating surface are

I. II. III. IV.

17 16 13 6

323

CANE SUGAE.

Per square foot of heating surface per hour a quadruple will receive
normally 1600 B T.U. ; the first vessel then utilizes 1600 — 17 = 1583
B.T.U. ; the second vessel receives 1583 B.T.U., and utilizes 1583 — 16 =
1567 B.T.U. ; similarly the third and fourth vessels utilize 1554 B.T.TJ. and
1548 B.T.U.

The useful effect then is 6252 B.T.U. and not 6400 B.T.U. ; that is to
eay, when in a non-radiating non-conducting quadruple a pound of steam will
evaporate four pounds of water, in a naked wrought-iron quadruple it will
evaporate 3-906 pounds; this loss will however be recoverable at quadruple
effect, so that for every four pounds of water evaporated '023 lb, steam, or say
22 B.T.U. are to be made up ; in a factory evaporating 60,000 Ibs. water per
hour the B.T.U. to be made up will
then be 330,000. In Chapter XIX.
a pound of megass is estimated as
affording for factory purpose 2922
B.T.U., so that the loss per hour in
radiation from a 10,000 square foot
naked standard evaporator is of the
order 113 Ibs. of megass or 2712 Ibs.
per day.

It is not unusual to see evapora-
tors only protected in part ; what is
the actual loss is almost impossible
to say ; this calculation shows, how-
ever, that the loss is quite appreciable
and well worth saving.

FIG. 180.

Utilization of Vapours
from the last Body.— A not

negligible economy of heat may be

obtained by using the vapours from

the last body to heat cold juices ; the

temperature to which the juice can

be heated depends, of course, on the

degree of vacuum in the last body; a 25 inch vacuum corresponds to a

temperature 133°F., and with that vacuum this is the highest temperature to

which the juice can be raised. A numerical example will make the economy

of this scheme clear.

Let there be evaporated under a 25 inch vacuum in the last body of
a multiple effect 233 Ibs. water per 1000 Ibs. of juice; the condensation of this
quantity of vapour will afford 238,126 B.T.U. Now, taking the specific heat
of juice as 0-9 and the initial temperature as 84° F., to raise 1000 Ibs. from
84° F. to 133° F. requires 44,100 B.T.U., so that 18'5 per cent, of the vapour

324

THE EVAPORATION OF THE JUICE TO SYRUP.

can be condensed by the juice. The megass corresponding to 1 000 Ibs. of juice
will roughly afford 1,000,000 B.T.U., so that the saving calculated on the
megass available for fuel will be between 4 and 5 per cent.

If this scheme is used it must be remembered that the juice is at
atmospheric pressure and the heating vapour under a high vacuum ; unless the
the apparatus is carefully constructed and maintained in good order there is
then danger of juice being carried away int.o the condenser.

Condensers. — The condensers which find use in forming and main-
taining the vacuum in the last body of an effect may be classed as jet or surface

condensers, or again as dry or wet con-
densers. Surface condensers are only used
where the vapour from the last body is
used to heat juices, as explained imme-
diately above.

The injection condenser, usually
employed to condense the vapours given
off from the last body of an effect, consists
essentially of a cast-iron cylindrical body
connected by a pipe, called the vapour pipe,
to the vapour space of the effect, and also
by a second pipe to the suction of an air
pump ; a third pipe called the injection
pipe leads water from a well to the con-
denser. A vacuum being formed in the
condenser by means of the pump, water
enters the condenser under the influence of
atmospheric pressure. The vapour given
off from the effect meeting the stream of
cold water is condensed, and the vacuum
maintained ; the condenser water and
incondensible gases pass to the pump and
are there discharged.

As the efficiency of a multiple effect depends very largely on the vacuum
in the last body, and this in turn on the completeness of the condensation,
attention to the design of the condenser is important. The commonest method
of distributing the injection water within the condenser is by means of a rose ;
with this arrangement there is liability of the holes becoming choked,
especially when any but the cleanest water is available. Better arrangements
are shown in Figs. 180 and 181. In the form shown in Fig. 180 the vapour
enters at a and the injection water at b ; the whole then follows the path
indicated by the arrows through the apertures in the plates, and is discharged
at d to the air pump. In the form shown in Fig. 181 the injection water

FIG. 181.

325

CANE SUGAR.

enters at J, overflows over a series of rings and discs in a fine shower, meeting
the vapour which moves in the opposite direction forming what is known as a
counter- current condenser ; as shown this form is applied to what is termed
the dry vacuum. The method of this form will be readily understood on
referring to Fig. 181 ; a is a pipe more than 33 ft. high with its lower end
immersed in a tank of water ; the atmospheric pressure will support a column
of water 33ft. high, and above this will be a vacuum. Into the condenser
water is pumped through the pipe b ; this water overflowing at e meets the
vapour from the effect conducted through the pipe d. The steam is condensed,
and, together with the injection water, discharges itself on to the surface of
the column a, and is eventually discharged into the tank/. The incondensible
gases are drawn off by an air pump through c.

A large number of patterns of condensers are made, the distribution of the
cooling water being very frequently obtained by devices similar to that shown in
Fig. 181, the arrangement of the rings and discs being capable of great variety.

FIG. 182.

Each of these systems has its advantages ; a more complete vacuum can
be obtained with the dry air pump, but in general two pumps are required ;
in certain cases where a natural head of water exists the lifting pump may be
dispensed with. In the wet system with large plants the size of the pump
becomes very inconvenient.

It is impossible to calculate from first principles what should be the size
of condensers; Jelinek recommends that they should be not less than 1-5, and
Horsin-Deon from 2-5 to 3 times the volume of the pump.

Central Condensation.— Instead of each unit having its own
condenser and pump, it is now often the practice to instal one central con-
denser and pump. A very great economy in steam, piping, oil, repairs, and
attendance is thus obtained. In such a case a dry vacuum pump should be
used, as a wet pump would have to be of exaggerated dimensions in a factory

326

THE EVAPORATION OF THE JUICE TO SYRUP.

of any size. In Fig. 182 is shown in plan a convenient method of arranging
the evaporators and pans for use with a central condenser ; the triple is shown
at a, the pans at b, both leading to the vapour main c connected to the central
condenser d.

Vacuum Pumps, — The pumps used in sugar factories to create
and to maintain the vacuum fall into two main classes — dry and
wet vacuum pumps. In the former type the incondensible gases and the
water used in condensation are removed separately, and in the latter class
together.

In Fig. 183 is given a sectional view of a vertical pump. At a is the
piston or bucket, at b the foot or suction valves, and at c the discharge valves.
These pumps are usually worked in pairs off a beam engine, and are not to be
found in recent factories ; in older factories as many as six or eight pumps may

be worked off one beam, a method which,
while economizing steam and labour, runs
the risk of stopping the whole factory in case
of a small mishap.

In Fig. 18J/. is shown a horizontal torpedo
plunger pump, of which many have been and
are being used in recent factories. The
plunger e moving from right to left, the
valve a ' opens and water enters and fills the
space behind the plunger ; at the same time
ijp i i n m i » gaa| the water in front of the plunger is discharged

i- -J^ix-- — ->JL \ through the valve b ; the valves a and b being

closed, the water is discharged through d
into the main factory sewer. The valves
shown at b and b' are india rubber disc valves
resting on a perforated iron or brass grill ;
those shown at a and a' are clack valves
working on a hinge ; in modern works it is
the former type of valves that is employed.
Pumps of this type cannot be worked

efficiently at a greater speed than 40 revolutions per minute, as it is important
that the air drawn in be expelled as completely as possible ; this only occurs
when the air is allowed to pass through the water, then expelled, followed
by the water. If the pump works at a high speed, the water is agitated, air
cannot pass through, and more air is left in the barrel than would be the case
at a lower speed.

The above-described pump is the type usually provided by European
engineering firms ; where factories have been erected under the influence of
United States engineers, wet vacuum pumps of or derived from the

FIG. 183.

327

CANE SUGAK.

328

THE EVAPORATION OF THE JUICE TO SYKUP.

Wafe

Steam

Worthington type are often used ; a section through such a pump is shown
in Fig. 185.

A wet vacuum pump that has heen extensively installed is the Edwards*
patent pump, which allows the air to pass naturally through the water,
instead of being churned up with it, as always happens to some extent in the
ordinary type. This pump is shown in vertical section in Fig. 186. Water
from the condenser flows by way of d to the reservoir c; the conical bucket I
on the down stroke forces the water into the barrel of the pump ; as soon

as the bucket rises the entry of water by
way of d is closed until the bucket has
passed, and the water which has been
projected into the barrel is lifted and
discharged through the valves at a, passing
away at e ; at g is a relief valve. The
incondensible gases are free to escape to
the space above the water. These pumps
are made double or treble barrelled, so
that their action is practically continuous.

Pumps used to remove the inconden-
sible gases in connection with the dry
vacuum are generally of the slide valve
pattern ; in the earlier pumps at each
stroke a certain amount of air was left in
the barrel of the pump, to the detriment
of the efficiency. To overcome this pumps
are fitted with an arrangement whereby
at the end of the stroke, communication is
made between the two faces of the piston,
and the compressed air in front of the
piston escapes into the exhausted space
behind. There are many excellent designs
obtaining this ' equalization of pressure,'
that due to the firm of Wegelin & Hiibner
being shown in Fig. 187. [There are three valves, a, b, and c, known
as the distributing, equalizing, and delivery valves ; the valve a is designed to
allow the air to enter or depart and to connect the suction or discharge to the
pan or atmosphere ; the delivery valve c on the valve a is for the escape of air
and to prevent air returning to the pump ; the equalizing valve b is for the
purpose of connecting the channels d when the piston is at the end of the
stroke When the piston is at the end of a stroke the valve a is nearly central
and the discharge and suction ports are closed ; at this moment the equalizing
valve b makes connection between the two faces of the piston by means of the

FIG. 185.

329

CANE SUGAR.

channel d and equalizes the pressure on both sides of the piston ; the valve I
now closes and a opens, and as the piston moves from right to left air is drawn
into the vacuum ; the equalizing valve I remains closed and the suctiun and
delivery ports open ; at the end of the stroke the valve a is again nearly central
and the process described above repeats itself.

The Blancke air pump is of recent introduction and uses flap valves ; it is
shown in Fig. 188. The motion of the cylinder is from left to right, so that
gases are being aspirated in on the left hand side and discharged on the right

FIG. 186.

hand side. The suction valve is composed of a series of sleeves, with rectan-
gular openings, A and B, and a ring and flap valve C telescoping together and
forming the annular spaces C and D. E is a spring, helping to close the valve
under a slight difference of pressure. On the compression side of the pump
all of the sleeves of the valve are forced together, and the annular spaces C;
and D7 and the openings Ay and B' are all closed ; the compressed air escapes
by el, f and g' ; on the aspirating side these openings are closed by the spring
H. The discharge valves are arranged on the lower side of the pump so as to
facilitate the removal of water.

330

THE EVAPORATION OF THE JUICE TO SYRUP.

Size of Pumps. — Although it is impossible to calculate on first
principles the necessary sizes of pumps to maintain a vacuum, certain principles
can be developed : the treatment here adopted is mainly after Hausbrand.

FIG. 187.

The pressure in a condenser is made up of two parts : a. the pressure due to
the water vapour which depends only on the temperature of the water ; b.
that due to the incondensible gases (referred to below as Air). Thus, with a

pf

FIG. 188.

vacuum of 24 inches, the pressure is 2'92 Ibs. per square inch. Let the tem-
perature of the water in the condenser be 100° F. ; the pressure of water vapour
at this temperature is '95 Ibs. per square inch ; hence the gases are at a

331

CANE SUGAR.

pressure of 1-97 Ibs. per square inch. As the temperature of the water
increases so does its vapour pressure, and consequently the gases are at a lower
pressure. The volume occupied by air or any gas is inversely proportional to
the pressure ; hence the colder the condenser the less is the specific
volume of the gases. As illustrative of the variation in gas pressure
in a condenser, there is given below the pressure of the gases where the
vacuum is 24 inches or 2*92 Ibs. per square inch, and where the temperatures
are as shown.

Temperature
F°

Pressure of gases.
Lbs. per sq. in.

Temperature
F°

Pressure of gases.
Lbs. per sq. in.

80

2-41

120

1-25

90

2-22

130

•70

100

1-97

140

•04

110

1-65

Hence when the temperature is 140° F. the gases will occupy sixty times as
great a specific volume as when the temperature is 80° F. Gases in condensers
arrive from the water used in cooling, from decompositions in the process of
boiling the juice, and from leaks in the apparatus. For the moment only the
first source will be considered. The gases dissolved from air by water,
following on the determinations of Roscoe and Lunt and of Winkler may be
thus expressed.

Temperature

60
70
80
90

Lbs. Gases Dissolved per 1000
Lbs. of Water*

•0266
•0241
•0217
•0195

The amount of water used to obtain the condensation of the vapour is
given by the expression w = — - — - - , where w is the water used per unit

tl

and t2 are the initial and

weight of vapour, h is the total heat of the vapour,
final temperatures of the cooling water.

For a 24-inch vacuum with cooling water at 60° F., the weights of water
required to obtain different temperatures in the condenser, and hence in the
discharge water, are as shown in the table below, which also includes the
pounds of gases from the water.

* The gases dissolved by water from air are very nearly in the proportion of two volumes
of nitrogen to one of oxygen ; it is here assumed that air itself is dissolved ; the calculation
is barely appreciably affected and the conclusion not at all.

332

THE EVAPORATION OF THE JUICE TO SYRUP.

Temperature of
Discharge Water.
F°

Weight of Water per
Pound of Vapour
Condensed.

Pounds of Gases
from Water.

80

50-4

•001365

90

33-3

•000902

100

24-7

•000669

110

19-6

•000531

120

16-1

•000436

130

13-7

•000371

140

11-8

•000320

The volume of 1 Ib. of air in cubic feet is given by the expression

•3697 (459-4 + Q
p

where t is the temperature in "Fahrenheit degrees, and p is the pressure in pounds
per square inch. In the table below are given for a vacuum of 24 inches, for
cooling water at 60° P., and for discharge water at the indicated temperatures,
the cubic feet of water, the cubic feet of gases, and the combined volume of
cooling water, condensed steam and gases, per pound of steam condensed : —

Temperature of the
Discharge Water

Cubic Feet of
Cooling Water.

Cubic Feet of
Gases.

Cubic Feet of
Gases and Water.

80

•8192

•1129

•9321

90

•5888

•0825

•6713

100

•4112

•0703

•4815

110

•2996

•0683

•3649

120

•2736

•0747

•3483

130

•2554

•1155

•3709

140

•2049

1-7712

1-9761

On examining these figures it will be observed that the volume of the
gases at first decreases with decreasing quantities of water, reaches a minimum
and tben rapidly increases; hence if the gases present in a condenser are propor-
tional to the amount of cooling water admitted, there is a definite temperature in
the waste water at which the volume of air is least; this temperature in the
waste water is then the OPTIMUM for the particular condition, and it controls
the proper •amount of cooling water to be admitted. It is, however, quite
impossible to calculate for actual use where this optimum temperature lies,
since the amount of air entering the condenser is quite unknown ; in a tight
apparatus, and if the juice gives off no gas, and if the heating steam is air free,
then it could be calculated with reasonable accuracy. As the matter stands,
however, all that can be said is that such an optimum condition exists and that
it can probably be found by trial and error for each apparatus.

333

CANE SUGAK.

If a series of calculations be made for different vacua in order to obtain
the optimum temperature of discharge on the supposition that the gases intro-
duced are proportional to the amount of water, it will be found that as the water
increases in temperature so does the quantity required. The calculation leads
to the following very rough approximation : With initial temperatures of 60°,
70°, 80°, 90° F., the water admitted should be about 10, 25, 35, and 50 times
the amount of steam to be condensed.

If calculations on the principles assumed above be made, it will be found
for vacua of 24, 25, 26, 27 inches that the volume of gases is very roughly
as 6, 9, 15, and 25; i.e., on this supposition a pump to produce a 27-inch

vacuum must be -~- times as large as one to produce a 24 inch vacuum. If,

however, a quantity of air, x, enters the condenser which is independent of the
quantity of water admitted, then the sizes of the pump capacity will be as
25 + x : 6 -f x, and as x is positive the ratio of pump capacity will be less
than calculated above ; if, however, x is small, as should be the case in a well-
built evaporator, a ratio similar to that calculated will be found.

The dry air pump has only to remove the air in the water passing down
the barometric column. Since the air is last of all in contact with freshly
entering cooling water, it will approximate in temperature to the cooling water.
Also since a counter current system of cooling is used, less quantities of water
are required. If a series of calculations be made on the lines developed above,
comparing the volume of air for the most favourable conditions with wet and
dry condensation, it will be found that on an average the volume of air with
dry condensation is one-third that obtained with wet condensation. This
comparison shows how small need be a dry vacuum pump compared with a wet
vacuum pump ; in addition the efficiency and speed of an air pump is much
greater than that of a water and air pump.

Empirical rules are very dangerous tools, and when the very variant
conditions described above are remembered, it will bo at once seen how foolish
it is to attempt to give any hard and fast rule connecting size of pump and
capacity of evaporator, since this will vary —

(a) With temperature of cooling water.

(i) With the efficiency of the apparatus as regards air leaks.

(c) With the amount of air in the heating steam which finds its way

eventually to the condenser.

(d) With the vacuum considered desirable.

Of the empirical relations the following may be mentioned : —

In marine engineering practice the pump displacement is five times the
volume of water to be removed. This would be a very low capacity for sugar
house evaporators.

334

THE EVAPORATION OF THE JUICE TO SYRUP.

Jelinek estimated that the pump should displace -3 cubic metre per kilo, of
vapour ; this equals 4 -8 cubic feet per Ib. of vapour, and as it applies to European
conditions with cold cooling water would be on the low side for tropical conditions.

Horsin Deon estimates that the wet air pump should displace twelve
times the volume of water to be discharged. These rules will be found to
give capacities larger than are often observed in practice.

With dry vacuum it has been found that a much smaller cylinder capacity
than that required for a wet air pump is necessary, and as an empirical rule it
may be stated that the displacement of the dry air pump need be only one-
third that necessary for a wet air pump.

Cooling Towers. — In districts where water is scarce it is necessary
to use over and over again the condenser water, which has thus to be cooled
each time after use ; cooling is effected by the action of the air applied either
in open or closed towers. The open type generally consists of a skeleton
framing of angle iron up to 30 feet high with three or four lower stages ; on
these are placed layers of faggots or brushwood ; the water is delivered by a
pump to the highest stage and distributed by gutters over the faggots and
falling down is collected in a reservoir at the bottom. A second design consists
of a series of steps down which the water flows in a cascade.

Alternatively, a brick shaft with a water distributing device inside is
employed ; in this case a fan is required to force cooling air up the shaft. The
United States makers of the Worthington pump employ such a scheme. The
distributing device is a sprinkler (of principle identical with that described on
page 305) ; the cooling surface consists of a number of cylindrical tiles placed
vertically the water flowing down these both internally and externally.

In a fourth method, injectors of the Korting pattern arranged round the
periphery of a pipe throw the warm water upwards in a fine shower.

Under tropical conditions with cooling air at about 80° F., and condenser
water at about 140° F., at the very least 1 sq. ft. cooling surface will be
required per gallon of water per hour, to be cooled to 100° F. and an excess of
this quantity is to be desired.

Scale in Evaporators.— Scale deposited on the tubes of evaporators
is due either to suspended matters carried forward in the juice or to the
deposit of dissolved bodies due to the concentration of the juice.

The elimination of the first cause can be obtained by a filtration of the juice
en masse, either through mechanical filters or through sand filters ; a useful
effect may also be obtained by passing the juice through strainers of very fine
mesh. A good filtration of the juice has an enormous effect in the prevention
of scale, and accordingly in increasing the efficiency of the apparatus. The
interfiltration of the partially concentrated juice on its way from vessel to
vessel with the view of removing the matter deposited on concentration has
also been employed.

335

CANE SUGAR.

Failing these appliances, the prevention of scale can only be controlled by
care in clarification. Excessive scale in evaporators can often be traced to bad
clarification and imperfect settling, that is to say, to lack of craft skill on the
part of the responsible workman ; too little lime often results in a badly
settling juice.

Yarious mechanical devices have been employed to diminish the deposit of
scale. Of these may be mentioned that of Novak,3 who suspends from the
dome of the vessel chains which hang down in the tubes ; the chains either
depend from springs or are supported in pairs from the end of a suspended
pivoted arm ; the motion of the liquid keeps the chains moving against the
sides of the tubes, and a part of the scale also deposits on the chains
themselves.

Lagrell and Chantrelle3 devised the scheme of placing a hollow rod, of
nearly the same specific gravity as that of the liquid in each vessel, inside
each tube ; along this rod is cut a spiral ; the motion of the liquid keeps this
rod continually rotating against the side of the tube.

The Lillie apparatus is designed so that the direction of flow can be
changed at will, and it is claimed that this change of movement prevents or
lessens the deposit of scale.

The chief bodies that occur in the deposit of scale are the silicates, phos-
phates, and sulphate of lime ; the two former seem to be of general occurrence ;
but a sulphate scale in factories not employing sulphur does not appear to be
universal ; it does not occur except in small quantities in the analyses quoted
below due to Pellet and Geerligs, but occurs in large quantities in some of
those due to Peck13 of Hawaiian scales.

Phosphate of lime does not, according to Geerligs and Tervooren14, occur
in juices in solution, but in a colloid state, and hence does not occur in scales
from juices which have been filtered, and they state that the same is also true
of silica. Peck13, however, has found phosphate of lime in a state of true
solution, the amount decreasing with the quantity of lime used in clarification.

Prom the analyses quoted below it will be seen that it is in the earlier
vessels that phosphates are deposited, silicates predominating in the later ones.

The ' fats ' that occur in scales are due to the cane wax and also,
according to Shorey16, to the decomposition of the lecithins of the cane.

The removal of the scale is only to be obtained by mechanical means with
scrapers and wire brushes, preceded by a preliminary treatment with appro-
priate solvents. Phosphate scales are best treated with hydrochloric acid, and
silicate scales with caustic soda, in 1 per cent, solution. Sulphate scales are
more troublesome to remove, and are best treated by first boiling with sodium
carbonate and then with hydrochloric acid ; the action of the sodium carbonate
is to convert the sulphate of lime to carbonate, which is then attacked by the
acid.

336

FIG. 18.
ISCAMBINE.

4

SIZE

PLATE XVII

THE EVAPORATION OP THE JUICE TO SYRUP.
COMPOSITION OF SCALE IN EVAPORATORS.

First Body.

Second Body.

Third Body.

Water and Organic Matter

29-80

26-70

18-60

Silica

•40

23-40

69-80

Iron and Alumina

3-80

9-98

2-80

Lime

46-30

25-80

6-80

Magnesia

1-36

•81

1-08

Phosphoric Acid

17-10

11-70

trace

Sulphuric Acid

•00

•00

trace

Copper

trace

trace

trace

Undetermined

1-24

1-61

•92

(PELLET.)

First
Vessel.

Second
Vessel.

Third
Vessel.

Fourth

Vessel.

Phosphate of Lime
Sulphate of Lime

57-85
2-02

56-98
1-92

15-02
•54

7-49
1-65

Carbonate of Lime

3-25

4-68

19-55

9-93

Silicate of Lime

7-86

13-31

•71

7-02

Oxalate of Lime

....

....

11-32

11-27

Iron Oxide

2-03

1-53

2-31

2-58

Combustible Matter
Silica

20-37
7-79

13-41
7-43

11-04
39-26

5-08
54-34

(GrEEBLIGS.)

First
Body.

First
Body.

Second
Body.

Second
Body.

Third
Body.

Third
Body.

Fourth
Body.

Fourth
Body.

Silica

5-91

17-08

10-43

•36

6-17

36-31

52-51

24-65

Iron and Alumina.

1-45

2-32

2-18

3-42

•28

•84

3-05

•77

Lime

48-33

44-59

44-94

51-44

44-47

31-87

25-24

61-95

Magnesia

3-79

•75

3-37

2-51

•46

2-94

2-55

1-22

Phosphoric Acid . .

38-62

8-98

32-22

40-00

1-22

25-71

9-43

8-00

Sulphuric Acid . .

1-60

26-60

6-08

1-79

46-02

2-74

6-70

3-44

(PECK.)
Peck's analyses are expressed as percentages on the mineral matter of the

scale.

337

22

CANE SUGAR.

REFERENCES IN CHAPTER XVI.

1. Ware's Beet Sugar Manufacture, p. 122.

2. Zeits. fur Zucker. in Bb'hmen, 21, 169.

3. Quoted in Ware's Beet Sugar Manufacture.

4. Bull. Assoc., 27, 207.

5. 7. S. J., 42.

6. Butt. Assoc., 15, 16.

7. H.P.M., December, 1904.

8. Evaporating, Condensing, and Cooling Apparatus. Hausbrand.

9. Journal des Fabricants de Sucre.

10. Zeits. fiir Zucker. in Bb'hmen., 25, 176.

11. S. C., 135, 136.

12. Zeits. fiir Zucker. in Bb'hmen. 7, 187.

13. Bull. 21, Agric. H.S.P.A.

14. /. S. J., 85.

15. J. A. C. S., XX., 113.

338

CHAPTER XVII.
THE CONCENTRATION OP THE SYRTJP TO MASSECUITE.

The juice after being treated in the multiple effect evaporator emerges as
a thick syrup of density about 1'25, and contains about 55 per cent, of solids
in solution. Before being passed on to the vacuum pan to be boiled to grain
it is sometimes subjected to a further treatment. This treatment may be
either mechanical or chemical ; when high class consumption sugars are being
made the syrup is sometimes sulphured or treated with phosphoric acid or other
decolourant ; this treatment is often combined with a filtration of the syrup in
sand filters or in the mechanical filters already described; in other factories
the only treatment that the syrup receives is that it is allowed to stand and to
deposit its suspended matter ; the practice of reheating the syrup in connec-
tion with steam economy schemes has been described in Chapter XYI.

In the vacuum pan the syrup is further concentrated until it is a magma
of crystals of sugar and mother liquor ; the usual routine processes followed
are outlined below ; the magma of crystals of sugar and mother liquor is
known as massecuite.

Processes followed. — In the actual routine work the processes
followed to obtain the sugar in the juice are as below.

1. Repeated Soilings. — The syrup is boiled to a masse cuite and the cry-
stals separated from the mother liquor giving first sugar and first molasses ;
the first molasses are boiled into second massecuite and from this is obtained
second sugar and second molasses ; this process is carried on until fourth or
even fifth sugar is obtained after which the molasses are, or should be,
exhausted ; the number of operations required to obtain exhausted molasses
depends very largely on the initial purity of the juice ; the purer the juice the
purer being the first molasses and so on. The first massecuite may be cooled
before the crystals are separated from the mother liquor or it may be treated
direct from the pan ; if cooled, it may be cooled at rest or in motion. With
juices of purity 85 or over, the first molasses are generally pure enough to boil
to grain ; other first molasses, and in all cases second and subsequent molasses,
are boiled blank, «'.<?., crystals are not formed in the pan but appear after the
mass has been struck out, and allowed to cool for a number of days.

This scheme gives as many as four or even five grades of sugar and is
wasteful of time, fuel, and labour ; in addition, the third and fourth sugars
will often not be treated in the centrifugals for a whole year after they are
made, entailing an excessive floor space and the locking up of much money.

339

CANE SUGAR.

2. Return of Molasses. — In many factories molasses from first massecuites
are worked up with the syrup and are not boiled separately, a mixed strike of
syrup and molasses being obtained; from this strike a high grade sugar will
be obtained, and often one boiling of the resulting molasses is enough to
separate them into crystals and exhausted molasses. A high initial purity in
the juice is demanded for the best use of this process, which is most applicable
in connection with crystallization in motion schemes.

3. Return of Low Products. — The product obtained from massecuites of
low purity boiled blank contain generally less than 90 per cent, of sugar, and
their sale as such is in general unremunerative ; they are usually subjected to
a process of refining in the factory either by being melted in the juices or by
being used as ' seed ' in the pan ; when used in the latter way the process of
granulating the syrup is dispensed with ; the fine grained low sugar is taken
into the pan in which there is already a quantity of syrup, and the deposit
of sugar from the concentrated syrup in the pan takes place on the crystals
already present.

4. Suppression of Low Products. — By this term is meant processes where
low products are entirely suppressed, not by the clumsy process of re-melting
them but by obtaining an exhausted molasses without their appearance ; this
depends on the carefully controlled return of the molasses combined with
cooling in motion, and is discussed subsequently.

Of these processes the last is the most rational one and is described in
detail afterwards. It is shown also below that the purer the massecuite the
purer are the resulting molasses ; the return of low sugars increases the purity
of the massecuites and hence of the molasses, while it is the object of the
process of manufacture to reduce this as much as possible in each step ; in
addition continual return of low products keeps sugar in process longer, thus
increasing entrainment and other obscure losses and adds to the work of the
centrifugals as part of the sugar is cured at least twice.

Standard Type of Vacuum Pan.— The vacuum pan is the
name given to the vessel in which the final concentration takes place ; the
means of obtaining and maintaining the vacuum are precisely similar to those
given in the preceding chapter, and the principles detailed there are, mutatis
mutandis, applicable to the single effect pan. Some points of special interest
are, however, discussed later. The vacuum pan was invented early in the
nineteenth century by Howard, whose name is also associated with the
invention of the filter-press. As made by him the apparatus consisted of a
double-bottomed shallow iron pan, steam being admitted to the double-bottom ;
a partial vacuum was obtained by condensing the vapour given off by a jet of
water allowed to gravitate down from an overhead tank ; no pump was at first
employed.

340

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

341

CANE SUGAR.

The great majority of vacuum pans in use at the present day consist of a
vertical cylindrical iron body of approximately equal length and width ; this
is often called the belt and is covered on the top by a spherical or conical cap
called the dome ; on the dome is placed the head box whence leads the vapour
pipe to the pump ; the lower portion of the pan is formed by an inverted cone
called the saucer or well ; the massecuite is discharged by a door at the centre
of the well. In what may be referred to as the Standard type of vacuum pan,
the heating surface consists of a number of helical copper coils, reaching from
the bottom to a little above the centre of the pan, and so arranged as to divide
the heating surface as uniformly as possible. In Fig. 189 is shown a view
partly in section and partly in elevation of a modern pan. The coils are seven
in number and are 4 J inches in diameter ; they are supported by stay rods
fixed to the side of the pan ; they each pass through the side of the pan and
•communicate with the steam pipe/; each coil has its own valve i whereby
steam can be admitted to any or all of them ; connection is also made to a
second pipe (not shown) carrying exhaust steam, so that this can be utilized
when available. In modern practice the maximum length of coil used is one
about 200 times the diameter ; beyond this length it is found that the con-
densed water does not leave the pipe fast enough to obtain an efficient heating
surface. The syrup is brought into the pan by the pipe I controlled by the
valve shown at a ; this pipe reaches down to the bottom of the pan, so that the
lighter syrup enters at the bottom and rising upwards becomes uniformly dis-
tributed ; each coil is closed by a flange d at its lowest point, which carries a
smaller pipe conveying the water of condensation to a steam trap or separator ;
at e is shown a pipe connected to the main steam whereby steam is introduced
to the interior of the pan for the purpose of removing sugar after a strike ; at
k is a manhole giving access to the pan, at g the vacuum gauge, at c a sight
glass, and at b the cock for breaking vacuum ; in the pan shown there are
approximately 1,000 square feet heating surface, the vessel holding when full
30 tons of massecuite. Special points with regard to this type of pan are
that the coils are often made double, alternately right and left handed
helices, and that the condensed water is trapped at every fifty feet or so
of coil.

Vertical Tube Pan. — A view of this pan is shown in Fig. 190, and
is often referred to as a calandria pan. The main portion of the heating surface
is contained in the vertical tube belt, the tubes of which are generally about
four inches in diameter ; the coil shown in the lower portion of the pan is for
the purpose of graining when only a small quantity of syrup is used for that
purpose ; it is also necessary so as to distribute the heating surface over the
lower portion of the apparatus. Frequently the upper tube plate of the
calandria is made sloping slightly downwards at an angle from the circum-
ference towards the centre of the pan with the object of preventing an accumu-

342

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

FIG. 190.

343

CANE SUGAR.

lation of massecuite on a level surface. In pans of this type about 30 per cent,
more heating surface can be arranged for than in the pans of standard pattern,
the gross cubical contents of the pans being the same.

Welner-Jelinek Pan. — The Welner-JelineJc^m^Q effect pan follows
the same general lines as the multiple evaporator ; instead, however, of the
sides terminating at right angles to the bottom, they are vertical for a part
only and afterwards slope in at an angle of 45°, being about two feet distant
from each other at the bottom of the pan. The heating surface consists of
horizontal tubes, about one inch in diameter and arranged in nests ; each tube
is distant from the next by about four inches; the nests are placed above each
other in stages of from two to four chambers, varying with the size of the pan,
and steam can be admitted independently to each stage.

Fm. 191.

Express Vacuum Pan. — The heating surface of this pan
is arranged similarly to that figured in the description of this type in
Chapter XVI.

Short Coil Pans. — The first vacuum pans constructed held less
than five tons of massecuite, and when built on the lines of the ' Standard '
type called for coils of only comparatively short length. With increase in size
of pans an increase in length of coil followed, and it was soon found that
the efficiency of the heating surface fell ; this was due to the steam becoming

344

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

condensed in the coil long before it reached the tail, so that a large portion was
so much dead surface. Several devices have been brought out to remedy this
defect, one of which is shown in Fig. 191 ; it is known as the ' lyre coil.'' As
many as eight coils form a nest in one plane which is tilted a little from the
horizontal so as to facilitate drainage ; the ends of the coils pass through

FIG. 192.

the walls of the pan into collector boxes. In a pan of this type containing,
say, nine nests, the collector boxes will be divided by horizontal partitions
into three compartments, to any of which steam can be admitted or cut off
independently.

In these types it is usual to arrange a helical coil within the saucer of the
pan.

345

CANE SUGAR.

Greiner Pan. — The pan designed by Greiner was amongst the first
departures from the * Standard ' pattern. It was constructed with the idea of
obtaining a large heating surface and placing the same all in the lower part
of the pan, so that the whole heating surface would be in use from the start of
the boiling. As now made it is shown partly in section in Fig. 192. The
heating surface consists of a number of concentric elements supported on cast-
iron standards. Steam is admitted and condensed water taken away at the
bottom of each element ; the valve A controls the admission of steam to
the small elements used in the process of obtaining grain, and that at B to the
larger elements used when the pan is working at its full capacity.

Shape of Pan. — Following on the principles developed in Chapter
XVI. it is easy to see that high pans of small diameter will be less efficient
than shallower pans, since the height of the column of massecuite will
materially increase the boiling temperature of the mass ; on the other hand,
there are mechanical difficulties in the way of indefinitely increasing the
diameter of pans, and with helical coils as heating surface, as shown imme-
diately above, the longer coils required in pans of large diameter tend to
become very inefficient ; the most efficient shape of pan then becomes one
of considerable diameter in proportion to height, with a tubular or short coil
system of heating surface.

Technique of Boiling.— The actual process of boiling the pan may
be divided into three stages : the granulation, the growing of the crystals, and
the bringing up to strike. The granulation is effected by forming in the pan
a solution of sugar saturated at a certain temperature, and then by causing
the temperature to fall to make the sugar crystallize. Different methods for
effecting this exist : the temperature may be lowered by increasing the quan-
tity of injection water and so obtaining a more complete vacuum, by shutting
off the supply of steam from the coils, or by introducing a quantity of cold
syrup; in whatever way the granulation is obtained the sugar separates as
minute, barely visible crystals. In forming grain some pan boilers take in at
one charge the whole amount of syrup from which they intend to granulate,
and others take in smaller charges gradually working up to the requisite
amount. Instead of forming grain from the syrup the practice of seed grain is
extensively followed ; in this process a quantity of a small grained sugar
obtained from previous work is taken into the pan, together with the first
charge of syrup, and the crystals thus introduced form the points upon which
the sugar deposits in the subsequent process ; the sugar used is generally the
small grained sugar resulting from the after-boilings of molasses. One ton of
such sugar can in general be used as grain for every 25 or 30 tons of masse-
cuite that the pan holds. This procedure, besides saving time in boiling the
first charge of grain, forms a very economical method of suppressing a portion
of the low products. In forming grain the quantity of syrup used for granu-

346

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

lation depends on the type of sugar required ; when a large crystal is desired
only a small quantity of syrup is granulated. This process is known as
' graining low down.' Forming grain from a large quantity of syrup, known
as ' graining high up,' will result in a sugar with small crystals. After the
granulation has been effected, the next step is to feed the grain with charges
of syrup, the object of the operator being to deposit the sugar that now
separates on the crystals already formed and not to allow it to form new
crystals ('false grain' or 'dust'). To avoid the occurrence of a second crop of
crystals the pan must be boiled evenly, there must be no sudden alteration in
temperature due to variation in quantity of steam or injection water, or by
taking in too large charges of cold syrup which, by locally reducing the tem-
perature in a part of the pan, causes a deposit of a fresh crop of crystals.
The scheme of feeding the pan continuously instead of intermittently is
dangerous, as, owing to alterations in steam pressure over which the pan boiler
has no control, slight variations may result in false grain being formed.
Should this occur from any cause pan boilers have two methods for its removal:
one is to partly cut off the injection water and so raise the temperature within
the pan, the finer crystals dissolving ; the second method is to take in a large
charge of syrup or even juice which dissolves the finer crystals; this last method
is termed by pan boilers 'washing.' When making large grained sugars for
direct consumption skilful pan boilers frequently, during the boiling of the
strike, take in large charges of syrup for the purpose of dissolving the smaller
crystals ; this process is called ' opening out ' or ' boiling free,' and in skilful
hands gives large, fine, bold crystals, but with less skilled operators is liable to
cause a serious deposit of false grain. Winter's patent, referred to later,
gives another means of removing the smaller crystals.

WThen the pan is full no more syrup is taken in, but the temperature is
gradually raised by cutting off the injection water until the striking point,
which can only be determined by experience, is reached ; the water content to
which a strike can be boiled depends largely on the purity of the juice, but it
is also controlled by such influences as the size of the pan outlet, and time
available for striking the pan. The greater the purity the less may be the
water content, although an impure massecuite with more water than a pure
one may still have a greater degree Brix. After a pan has been once filled
it is often advisable to strike out only half, and to continue boiling on the
remainder ; this process is known as ' doubling,' and the discharged masse-
cuite is termed the • first cut ' ; the object is to save time and to obtain
a large grained sugar in the second and subsequent cuts. This process
may, with exceptionally pure juices, be continued four or five times, whilst
juices of low purity may not give a single 'double* ; in any case there is always
a point beyond which the sugar crystal refuses to grow, and any attempt to
further increase its size ends in a fresh deposit of minute crystals.

347

CANE SUGAR.

Heating1 Surface. — Calculations of the heating surface requisite for
vacuum pans can be made on the same lines as have already been given when
dealing with the designs of multiple effect evaporators; coefficients of the
heat transmission for the conditions in the vacuum pan were given there ; these
calculations are not of much avail as the data are uncertain and of necessity
vary with the actual conditions of working. Further, while in the multiple
evaporator the whole heating surface is constantly active and the juice level
remains constant, in the vacuum pan during part of the process only is the
whole of the heating surface in use, and the level of the contents of the pan is
constantly changing. This is the more marked the taller the pan is, and
consequently the higher the pan is the less is the efficiency of the heating
surface ; the effect of a high level in the liquid under treatment in decreasing
the mean temperature difference between heating steam and heated liquid was
explained in Chapter XVI., and a similar cause is at work in the vacuum
pan ; hence pans that are shallow in proportion to height are found to be
' quick boiling* pans. As an example of an actual case let the maximum
height of the massecuite in a pan be 10 feet, so that the average height for
the boiling is 5 feet ; the average density of the contents of the pan can be
only very approximately estimated; the syrup enters at a density of, say, 1*25,
and is discharged as massecuite at a density of about 1*50 ; allowing for the
decrease in density due to einulsioning with gases, as was done when dealing
with the multiple evaporator, the mean density of the boiling mass is found to
be about 1*21 ; the weight of a column of liquid 5 feet high and of density
1*21, and of 1-inch cross section, is equivalent to a column of mercury 5'34
inches high, or to a pressure of 2-62 Ibs. per square inch ; if the pressure of
the liberated vapour be taken as 2 '42 Ibs. per square inch corresponding to a
vacuum of 25 inches, the mean pressure of the vapour at the moment of its
formation is 2'62 + 2'42 =: 5*04 Ibs. per square inch, corresponding to a
temperature of 162°F., which may be taken as the mean temperature of the
boiling mass.

Now the mean pressure of the* steam in the coils may be taken as 20 Ibs.
per square inch, corresponding to a temperature of 259° F. The difference in
temperature between the heating steam and the boiling liquid is then 97° F. ;
for a triple effect dealt with in the previous chapter a mean temperature
difference of 24-3° F. was obtained. A modern triple effect evaporator will
evaporate 6 Ibs. of water per square foot per hour, so that on these grounds a
single effect pan should evaporate under the conditions detailed about 24 Ibs.
As a matter of fact, experience has shown that in the single effect vacuum pan
an evaporation of only 12 to 15 Ibs. can be reckoned on; the greater density
of the material under treatment implying greater viscosity — and consequent
greater difficulty — for the disentanglement of vapour, and at the same time
decreasing the coefficient of transmission of heat. In addition, whatever be
the actual evaporation during working, for a part of the operation the whole

348

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

heating surface is not in use. As a rule, modern pans have a capacity of
about 70 Ibs. of massecuite per square foot of heating surface ; these data are
sufficient to calculate the size of pans for the concentration of any given
quantity of syrup.

The effect of a low vacuum in the single effect pan is not so noticeable as
affecting the temperature difference as in the multiple effect ; if in the example
worked above, a 27-inch vacuum be assumed, the mean pressure of the vapour
at the moment of its formation is found to be 3-86 Ibs. per square inch, corres-
ponding to a temperature of 152°F., and giving a temperature difference of
107°F. as compared with 97° F. or roughly 10 per cent. ; for the triple effect
considered in the previous chapter the same final vacua altered the tempera-
ture difference to the extent of 30 per cent.

Relation of Heating Sur-
face to Capacity. — In a standard
type of coil pan there will be per cubic
foot of capacity from 1*2 to T6 square
feet heating surface ; in a vertical tube
pan from 2 to 2*2 square feet; in a
lyre coil pan from 2-5 to 3 square
feet, and in a Welner-Jelinek pan from
2' 8 to 3 square feet.

Kind of Steam used.— In

general, in modern factories, and always
unless the engines are large steam con-
sumers, all the exhaust steam is used up
by the juice heater and multiple effect
apparatus, and none remains for the pans.
The majority of sugar manufacturers
object with considerable reason to the
use of high pressure steam in the pans,
and consequently the main steam is
reduced before entering the coils to a pressure generally lying between the
limits of 10 Ibs. and 20 Ibs. per square inch. The objection to the use of high
pressure steam is the tendency towards local overheating and caramelization of
the sugar. This danger is not so great if the circulation is kept very rapid,
and the use of high pressure steam adds very considerably to the capacity of a
pan, the passage of heat being proportional to the difference in temperature
between the exterior and interior of the coils; pans are now constructed,
especially by United States firms, to work with steam pressures of 50 Ibs. per
square inch or even more, but it is really doubtful if the use of high pressure
steam is to be advised.

FIG. 193.

349

CANE SUGAR.

In Chapter XVI., methods of steam economy, based on the use of the
' fore evaporator ' and on the use of ' extra steam ' are described ; the steam
of low temperature obtained in these schemes is in beet factories used as a
source of heat in the pans ; in such a case large heating surfaces become
essential and it is important that the heating surface be as efficient as possible,
a result to be obtained by the use of calandrias or of short length coils.

Special Devices in Pans.— Chiefly in the beet sugar industry
many specialized types of pans have been designed ; of particular interest are
those designed for a slow methodical concentration of the low products to
grain ; these designs are exemplified in the Freitag, Grosse, and Reboux arrange-
ments. The essential idea in these pans is a stirring device whereby the mass

Fm. 194.

is kept in slow methodical movement ; in the Freitag pan, the heating surface is
a vertical tube calandria and in the Grosse pan, Fig. 193, a system of coils.
The Reboux pan, Fig. 194, is peculiar in its arrangement and consists of a
horizontal cylinder ; the heating surface is made up of four separate systems
of tubes. In all these pans the stirring device makes about four revolutions
per minute.

With the object of obtaining a brisk movement of the thick viscid mass
in a pan, arrangements have been devised whereby lire steam or air is injected
into the lower part of the pan ; the injection of air was patented by Dr. Winter,
of Java, to the end that on nearing the completion of a strike the partial

350

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

destruction of the vacuum, causing a rise in temperature, would effect the
solution of small crystals, which would be recovered on subsequent cooling in
motion.

The importance of a well distributed feed of the syrup is recognized in the
Delavierre patent. In this arrangement a pipe is fixed around the saucer of
the pan ; this pipe communicates with the interior of the pan by a number
of valves, the aperture of which is about one- sixteenth of an inch ; the syrup
is pumped into a receiver connected with the pipe on which are these valves ;
the syrup is injected into the pan through these valves in a number of fine jets
whereby an extremely uniform distribution is obtained ; with this device it is
easy to obtain with but little attention a continuous feed of syrup into the pan.

Supersatliration. — A. saturated solution of sugar or of any soluble
body is one that can neither dissolve more sugar nor yet precipitate the
dissolved body as long as the temperature and other conditions are maintained
constant ; in any case, if the conditions are altered either by removing water
or by lowering the temperature, the separation of the sugar is not instantaneous
and an unstable supersaturated condition results. If S be the solubility of
sugar in water in saturated solution, and St be the solubility in a super-
saturated solution, Claassen terms the ratio ~ the coefficient of supersaturation,
and on this idea he has based a system of methodical pan boiling.

Before the granulation of the syrup in the pan can be obtained, a super-
saturated solution must be formed, and the higher the coefficient of supersatura-
tion at the granulation, the larger will be the number of crystals deposited,
and consequently the smaller will be the size of the crystals on the completion
of the strike ; referring to beet sugar conditions, Claassen states that a
coefficient of supersaturation of at least 1*2 is necessary, and that the average
is 1'5 to 1'6; if a lower coefficient than 1*2 is used there is risk of redissolving
the crystals on the addition of the next charge of syrup. During the process
of growing the grain it is necessary that a uniform supersaturation be main-
tained throughout the entire mass, as otherwise the crystals will grow unevenly,
and if a too high supersaturation obtain in any part of the pan a fresh crop of
crystals (false grain) may form. The evaporation is greatest in those parts
next the coils, and least in those parts next the inlet of cold syrup ; hence, to
obtain uniformity, the circulation of the mass and the distribution of the syrup
must be controlled. Devices affecting these points have already been discussed,
and it is well that the syrup should enter the pan at the least at a temperature
not lower than that there prevailing. As a guide at this period, Claassen states
that with a continuous feed of syrup a coefficient of supersaturation of I'l
should be maintained, and that with an intermittent feed the supply of syrup
should be cut off when the coefficient falls to 1, and opened when it rises to-
1-2 ; finally, at the end of the strike the coefficient should be raised to 1-3.

351

CANE SUGAR.

Algebraical Theory of Sugar Boiling.—

Let x =^ Brix of the massecuite.*

s =. solubility of sugar in the mother liquor or molasses.
p = purity of the massecuite.
m = purity of the molasses.
Then (1 — x} = water in the massecuite.

* (1 — x) — sugar in solution, i.e., in the molasses.
x (1 — p) = total non-sugar or impurities.

(For convenience of calculation these purities are referred to unity
instead of to 100 as is usual.)
Then

_ * (*— *0

~- 8 (\-x) + (\-p) x
and

ms

x —

8 -f- m — ms — mp ^

Let there be two massecuites of different purity, both boiled to the same
degree Brix, the solubility of the sugar in the mother liquor remaining the
same ; then as p increases \-p decreases, and the denominator in the expression
(1) decreases, so that the value of m increases.

It follows then that as the purity of a massecuite increases, so also
increases the purity of the mother liquor provided that the Brix to which the
massecuites are boiled remains the same.

In the table below are calculated values of the expression :

»(!—*)

s(l -x) + (l—p)x

for values of x = '90, s = 2'0 and p = 75 to 95, connecting purity of masse-
cuite and purity of resulting molasses when the Brix of the massecuite is
constant at 90 and solubility of sugar in molasses is 2*0

Purity
Massecuite.

Purity
Molasses.

Purity
Massecuite.

Purity
Molasses.

75

44.44

86

58-82

76

45-45

87

60-60

77

46-51

88

62-50

78

47-62

89

64-51

79

48-78

90

66-67

80

50-00

91

68-96

81

51-28

92

71-43

82

52-63

93

74-07

83

54-06

94

76-92

84

55-55

95

80-00

85

57-14

In what follows Brix is here used as synonymous with true total solids.

352

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

Actually in practice the purer the syrup the higher is the degree Brix
(i.e., the sugar boiler brings up the strike higher) so that so great a difference
in the purities of molasses from strikes of different purities will not be noticed.
It is, however, a matter of experience that high purities in the strike imply
high purities in the mother liquor or molasses.

The equation (2) above gives the degree Brix to which a massecuite must
be boiled to give molasses of any desired purity when the solubility of sugar
in the water remaining in the massecuite is known.

In the annexed table is calculated the degree Brix to which massecuites
of purity 46 to 95 must be boiled in order to give a mother liquor of 46 purity
when the solubility of sugar in the mother liquor is 1*8.

Values of the expression 100 x

s —

s-\-m — ms—mp
s 1-8 and m '46, and of p -46 to '95.

for values of

p

P

P

•46

79-65

•63

85-09

•80

91-35

•47

79-95

•64

85-44

•81

91-75

•48

80-25

•65

85-79

•82

92-15

•49

80-56

•66

86-14

•83

92-55

•50

80-86

•67

86-49

•84

92-96

•51

81-17

•68

86-85

•85

93-37

•52

81-49

•69

87-21

•86

93-79

•53

81-80

•70

87-57

•87

94-20

•54

82-12

•71

87-93

•88

94-62

•55

82-44

•72

88-30

•89

95-05

•56

82-76

•73

88-67

•90

95-48

•57

83-07

•74

89-04

•91

95-92

•58

83-42

•75

89-42

•92

96-35

•59

83-75

•76

89-80

•93

96-79

•60

84-08

•77

90-18

•94

97-24

•61

84-42

•78

90-57

•95

97-69

•62

84-76

•79

90-96

Now, according to the equation, it is possible by boiling to a sufficient con-
centration to obtain in one process exhausted molasses; thus a syrup of 90 purity
if boiled to a concentration of 95 -4 8 Brix would, on the data on which the table
was constructed, give molasses of 46 purity ; now from actual experience it is
known that often four operations are necessary in general to obtain this end ;
there is no real disagreement between theory and practice but the causes of
this are :

1 . It is impossible practically to boil any massecuite to so high a con-
centration as 95-48 ; a massecuite so highly concentrated would have no

353

23

CANE SUGAR.

circulation, it would bank up and burn on the coils and it would be a matter
of difficulty to remove it from the pans and to manipulate it afterwards.

2. A very supersaturated solution of sugar would be formed in the final
stages, from which, under the ordinary process of cooling at rest, sugar would
separate with extreme slowness and in a form not suited to be recovered in the
centrifugals.

By reducing the purity of a massecuite by the addition of molasses,
exhausted or unexhausted, it is possible to boil the massecuite to such a
concentration that all the sugar capable of recovery crystallizes out, and at
the same time the massecuite is sufficiently fluid to be capable of practical
manipulation.

On this argument all the schemes connected with crystallization in motion
and return of molasses processes are capable of simple algebraical treatment.

Dependence of the Amount of Sugar crystallized on the
absolute Amount of Water left in the Massecuite.— The

amount of sugar then that can be extracted as crystals from a massecuite
depends on the degree Brix to which the massecuite can be boiled, or, con-
versely, to the least possible amount of water which can be left in the masse-
cuite capable of retaining in solution the non-sugar, and it is immaterial, so
far as regards the amount of sugar that crystallizes, whether the concentration
is done in one or more operations. This is best shown by a worked out
example.

Let there be a syrup of 80 purity, let it be concentrated to a Brix of 90
and let the solubility of sugar in the mother liquor be two, i.e., for every one
part of water in the mother liquor Jet two parts of sugar be dissolved.
Then the masse cuite is of composition —

Water 10

Sugar in solution 20

Sugar as crystals 52

Non-sugar 18

100

Now let the 52 parts sugar as crystals be removed, leaving 48 parts of first
molasses of percentage composition —

Water 20-83

Sugar .. .... .. .. ... .... 41-66

Non-sugar 37-50

100

Brix 79-17

Purity .. . •':. =• 52-63

and the sugar removed per cent, on that originally present is —

100 x 52

= 72-22 per cent.

leaving 27 -78 per cent, in the molasses.

354

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

Now let these molasses be concentrated to a second massecuite at 90 Brix
and let one part of water hold in solution two parts of sugar.

Then the percentage composition of the second massecuite is —

Water 10

Sugar in solution 20

Sugar in crystals 27 '367

Non-sugar 42-633

100-00

Now let 27-367 sugar in crystals be removed. Then per 100 sugar
originally present there are removed.
27-367

X 27-78 = 16-07 per cent.

47-367

and the total amount of sugar removed in the two operations per 100 sugar
originally present is 72-22 + 16-07 = 88-29.

Now to find to what Brix the massecuite must be boiled in one operation
BO as to leave the same absolute amount of water in the massecuite, we can
proceed as follows. In the second massecuite above the non-sugar is 4-2633
times the water and the purity of the original syrup being 80, the sugar in
the original massecuite is four times as much as the non-sugar. Let x be the
water percentage in the massecuite boiled in one operation so that the absolute
amount of water left is the same as that in the two operations above.
Then

x + 4-263^ -f 17-0532* = 100

*?= 4-482

The composition of the massecuite boiled to this water content in one
operation will be

Water . . 4'482

Sugar in solution 8 -964

Sugar in crystals 67 '450

Non-sugar 19*104

and if the 67-450 sugar in crystals be removed, the amount of sugar extracted
per 100 sugar in the masse cuite is

67-450
— x 100 — 88-29 per cent,

the same percentage as was obtained before in two operations.

Crystallization in Motion.* — A complete crystallization in
motion or first-sugar and molasses process may be defined as "a scheme in
which the purities of massecuites are reduced to such a point that they are
capable of practical manipulation when concentrated to that point when the
water left is only just sufficient to hold in solution the non-sugar, combined

*As in other valuable processes there is no one inventor; Bocquin first in 1880 used a
crystallizer as now understood ; Wulff in 1884 gave a complete theory.

355

CANE SUGAR.

with the cooling of the massecuites in motion whereby the deposit of sugar
from supersaturated solution is accelerated and takes place on crystals already
formed."

The development of this scheme is traced below.

"When a strike of grained massecuite leaves the pan a portion of the sugar
is present as crystals and a portion is in solution ; on cooling, sugar is
deposited, and if the sugar is allowed to cool at rest new fine grain is formed
which is incapable of recovery as first product ; if such a strike is cooled in
motion the crystals already present are continually brought into contact with
fresh portions of the mother liquor and the sugar that is deposited forms on
the crystals initially present. The first schemes of crystallization in motion
had this for their object, and a very considerable increased return in first
product was obtained without in any way altering the system of repeated
boilings at that time general in cane sugar factories. Owing to the increased
yield in first product a first molasses of lower purity resulted and where a
factory took four boilings to obtain exhausted molasses the adoption of crystal-
lization in motion reduced the number of operations to two or to three,
besides obtaining a larger proportion of the output in the more valuable first
product.

This point was made the subject of direct experiments by Prinsen
Oeerligs3 in Java, who showed that a return of 64 per cent, of raw sugar was
obtained from massecuites cooled in motion compared with an average of 56
per cent, from similar massecuites cooled at rest, although the actual amount
of crystals present in all cases was very similar. This very simple scheme
gives most pronounced benefit when impurer juices are being worked, as
with these a more viscous mother liquor results and crystals deposited on
cooling go to form new fine grain, the less viscous mother liquors obtained
from purer juices allowing sugar separating on cooling to deposit on grain
already present.

Although this scheme went far towards reducing the amount of low
products it could not entirely suppress them, as the primary massecuites
could not be boiled to a concentration so great that all the sugar capable of
recovery separated, and various schemes have been devised to the end that all
the output is obtained as high grade product. These schemes are discussed
below.

Use of Exhausted Molasses. — Eeference to the table of values

s — ms

of the expression - shows that for a purity of 90, the

s -4- m — ms — mp

massecuite must contain 95 '48 per cent, of solids if it should give exhausted
molasses on curing ; such a massecuite would be impossible to obtain or to
work in the centrifugals ; but if to such a (hypothetical) massecuite exhausted
saturated molasses be added, no change in the massecuite, which can be itself

356

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

regarded as crystals and exhausted saturated molasses will occur; the two portions
of molasses will mix and the magma will be sufficiently fluid to separate into
crystals and molasses. On paper this scheme could be worked indefinitely, the
exhausted molasses passing continually unchanged through the process and
being regarded merely as a menstruum for obtaining a massecuite capable of
manipulation. Actually, however, the continued action of elevated temperatures
brings about obscure changes in the molasses which become ' gummy ' and
troublesome in the centrifugals.

Use Of Unexhausted Molasses.— Chiefly in Java and hence
known as the ' Java process,' a system of working has been developed which
admits of the obtaining of all the available sugar in a merchantable form ; this
can best be described by following through the details of the process. Initially
let there be syrup of 80 purity ; per 100 massecuite obtained from this syrup
there may be obtained 60 parts of crystals and 40 parts of molasses of 55
apparent purity ; let the next 100 parts of syrup massecuite be mixed with
these 40 parts of molasses ; then a mixed strike of about 72 purity will result.
From this strike molasses of about 45 apparent purity will accrue, there being
probably equal quantities of molasses and crystals obtained, so that the factory
now contains about 70 parts of molasses of about 45 purity. If to the next
100 parts of syrup masse cuite these 70 parts of molasses be added, a mixed
strike of purity about 66 purity will result; this strike on curing should
afford merchantable sugar and waste molasses of about 30 apparent or 45 true
purity.

It is easy to see how the control of this process can be based entirely on
the use of the algebraical theory developed above, that is to say, on the
principle that for every purity of massecuite there is a corresponding water
content at which exhausted molasses are obtainable.

The example detailed above suggests three operations as necessary to
obtain exhausted molasses, at the end of which the cycle starts again ; in a
number of factories the writer has seen the cycle reduced to two and even
when the initial purity was nearly 90; in these cases no syrup massecuite
was made but two strikes were boiled, one at a purity of about 75 and the other
at about 60, the molasses from the latter being removed in part and in part
used as a diluent for subsequent strikes. The writer prefers the first detailed
scheme, but much depends on the factory arrangements, the nature of the
juices, the kind of sugar desired, and the personel of the staff.

In all these schemes grain is formed from syrup and the molasses
are added subsequently ; different ways of obtaining the mixture can
be used.

1 . All the syrup intended to be used may be taken into the pan at once,
grain formed and the pan gradually filled up with the molasses

357

CANE SUGAR.

2. The molasses may be taken into the pan in one charge ; in this method
of working the syrup part of the charge is worked up in the usual way and
brought up to the striking point ; the predetermined quantity of molasses is
then heated, very conveniently in a second pan, somewhat above the tempera-
ture of the syrup massecuite and cut over with the syrup pan ; the molasses
should enter at the bottom of the pan, so that it may rise through and mix
with the syrup massecuite ; the whole mixed strike is then concentrated to a
degree corresponding to its purity and struck out.

3. The syrup and molasses may be mixed without the pan in carefully
regulated proportion ; this mixture may take place in the syrup tanks or the
molasses may be mixed with the juice and pass through the evaporators.

Whichever method of working is used it is easy to see that all reduce to
a scheme for the reduction of the purity of the massecuite to such a point
that it can be boiled to a water content capable of manipulation and at the
same time afford waste molasses.

Bock System. — This was one of the earliest systems put forward ; in
bare outline it is as follows : — A strike was boiled from syrup alone and struck
out into crystallizers ; two-thirds of this strike was cured as usual and the
resulting molasses collected, boiled blank, and struck out on to the remaining
third of the original strike, which was then cooled in motion and from which
exhausted molasses was obtained.

First Sugar and Molasses. — Strictly speaking, any process known
by this name should turn out one product only, separating the massecuites in
one process into marketable sugar and waste molasses. This could on paper
be effected by the use of exhausted molasses, all the strikes being boiled at a
purity of 65 or thereabouts. Actually the writer believes such a method is
not in any extended use. By the use of schemes described above all the sugar
is obtained as a high grade marketable product although the term ' first sugar
and molasses' is not strictly applicable to it, since the two products obtained
are not strictly of the same quality.

Reversed Process. — In the process described above the addition of
molasses to a grain massecuite formed the basis of the scheme ; a reversal of
this process consists in taking unexhausted molasses and boiling them blank
until they are of that degree Brix which will give exhausted molasses on cool-
ing ; to this masse cuite is added a quantity of sugar obtained from a previous
boiling ; the amount of sugar added is from 20 per cent, to 30 per cent, of the
weight of the massecuite ; the sugar is either taken into the pan or added to
the massecuite after it has been struck out into the containers in which it is
to be cooled in motion. This scheme, too, is easily seen to depend for its
success upon the careful control of the water content of the massecuite
boiled blank. The inception of this scheme is to be traced to Wullf's patent
of 1884.

358

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

Crystallization in Motion of Low Products.— In some
factories it is customary to cool in motion the low massecnites only after one or
two lots of crystals have been obtained. In such cases the massecuites are
usually allowed to stand until grain has begun to appear when they are
subjected to a stirring which is continued for about a week ; from this product
a low sugar is obtained which usually is not marketed directly but is remelted
and refined in the factory. Except for economy in floor space and for the
saving of money lying idle, this process has nothing to recommend it ; it is
much inferior in results to the processes described above ; its chief application
lies in factories which make a high grade white sugar where the addition of
molasses to the syrup is inadvisable.

Time for Cooling. — The strikes of higher purity are usually cooled
for 12-15 hours; those of lower purity whence exhausted molasses are
expected are cooled from 48-72 hours.

Crystallizer Capacity. — -For a complete separation of massecuites
into sugar and waste molasses 20 cubic feet of crystallizer capacity are required
per long ton of sugar per week ; less may serve but no margin is then allowed
for the miscarriages which occasionally happen.

Technique of Crystallization in Motion. — This process gives
great opportunity for observation and craft skill ; some points are mentioned
below.

Before taking molasses into the pan they should be cleaned by boiling in
an eliminating pan and the scum which rises to the surface skimmed off ; this
heating will also dissolve fine grain.

The size of the pans and crystallizers should be correlated, so that a
crystallizer takes a full or half charge of a pan.

For convenience of working all pans and tanks should be graduated, so
that the operators can know exactly what quantities of syrup and molasses are
in progress. During the process of cooling the massecuites should be inspected
frequently and if they become too thick, hot exhausted molasses may be
added as a diluent ; an experimental centrifugal is very useful in following up
the cooling process.

The stirrers should be completely immersed in the massecuites, else in
their rotation they will force air into the massecuite which will form an
emulsion and may make the molasses so light that they will not pass
through the wall of sugar in the centrifugal baskets.

Control of the Water Content of Massecuites.*— It has

been shown above that the success of these schemes depends on a knowledge
of the water content of the massecuite when it is struck from the pan ; this

* See Note in Appendix.
359

CANE SUGAR.

datum can be obtained in the laboratory several hours after the strike has been
finished, and in place of a laboratory analysis there is substituted the sugar
boiler's sense of touch. In 1898 Curin4 introduced into the beet sugar industry
an instrument called the brasmoscope designed to control the operation of pan
boiling and founded on the annexed principles.

Soiling point. — All liquids are constantly giving off vapour from their
surface and when the pressure of the vapour equals that of the surrounding
atmosphere the liquid boils ; as the pressure of the surrounding atmosphere
increases so does the boiling point of the liquid, and conversely with a fall of
pressure there is a corresponding fall in the boiling point ; when water or
other liquid boils under a pressure less than that normally due to the atmos-
phere, it is said to boil under reduced pressure or less correctly ' in vacuo.' It
is customary to express the pressure under which sugar solutions are boiled in
' inches of vacuum.' The normal pressure of the atmosphere will support a
column of mercury 29-92 inches high ; an absolute vacuum would then be
expressed as 29'92 inches, and a vacuum of 25 inches will mean that the
excess pressure of the atmosphere over the pressure in the vessel, in which
there is a vacuum of 25 inches, is 29'92 — 25 = 4'92 inches. This method of
expressing pressure less than one atmosphere is not altogether convenient, and
for many reasons it would be better to speak of a pan being boiled under a
pressure of 5 inches absolute, rather than as under a vacuum of 25 inches.
In the Appendix is given a table connecting the pressures and temperatures at
which water boils.

^Effect of dissolved solids on the boiling point. — The boiling point is increased
by the presence of dissolved solids and the following important relation con-
nects boiling point, amount of dissolved solid and pressure under which
ebullition occurs. ' The elevation of the boiling point due to the dissolved
solids is independent of the pressure under which ebullition occurs.' For
example, under a pressure of one atmosphere water boils at 212° F. and a
75 per cent, solution of sugar at 225'2° F. The elevation in the boiling
point is then 13-2° F. ; under a pressure of 4 inches of mercury (25'9
inches of vacuum) water boils at 125-6° F. ; a 75 per cent, solution of
sugar under the same pressure will then boil at 125-6+ 13-2 = 138'8° F.
The temperatures at which sugar solutions of different concentrations boil under
atmospheric pressure have been determined (see Table in Appendix) ; if then
the temperature of a boiling sugar solution be known, and also the pressure
under which ebullition occurs, then from the elevation of the boiling point
over and above the boiling point of water under the same pressure, the
amount of sugar in the boiling mass can be at once found. For example,
under a pressure of 4 inches of mercury a sugar solution boils at 159'4°
F. ; water under this pressure boils at 125'6" F. ; the elevation in the
boiling point then is 29-8° F. ; reference to the table of elevation of boiling
points of sugar solutions gives the percentage of sugar as 8 6 '2 5 per cent.

360

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

This relation is the basis of an instrument known as a brasmoscope or
brixometer.

The brasmoscope consists merely of an accurate thermometer (the bulb of
which is immersed in the boiling mass in the pan and placed so as not to be
affected by local causes such as the proximity of a steam coil) and an accurate
barometer pressure gauge, the ordinary aneroid gauges not being of sufficient
accuracy.

The form of barometer gauge usually found is
a syphon barometer, Fig. 195] this consists of a U tube
closed at the end A and open at the end B ; the tube
is filled with mercury and when held in a vertical
position the difference of level between the mercury
in the two limbs will give the pressure of the atmo-
sphere in inches of mercury ; this U tube is fixed on a
board carrying a scale and is adjusted so that the
level of mercury in the long limb is at the zero mark
when under atmospheric pressure ; if the open end
be now attached to a vessel in which there is a
reduced pressure, the mercury in the long limb will
fall until the difference in level is that due to the
pressure in the vessel connected to the short limb ;
the scale is so graduated as to give directly inches of
vacuum in the vessel to which the short limb is
attached. This instrument is not too convenient, as
the gauge has always to be set at the zero mark and
as a full of pressure of, say, 1 inch in the vessel
where the pressure is being measured only causes
the level of the mercury in the long limb to fall
half an inch, the level of the mercury in the short
limb at the same time rising half an inch. The
writer has devised the pressure gauge described below,
Fig. 196.

A is a shallow receptacle of thick glass partly
filled with mercury ; on the upper side at B is a

tubulure to be connected to the vapour space of the pan by stout rubber
tubing ; at C is the neck of the receptacle into which fits tightly the barometer
tubing D, graduated in tenths of an inch ; the receptacle A being filled with
mercury the graduated barometer tubing is then inserted in the neck of the
flask and mercury is sucked up above the level of the stop cock at E which is
then closed ; the mercury in A is then adjusted until its level is coincident
with the zero mark on D ; if then connection be made to the vapour space
of a vacuum apparatus by way of B, the height of the column of mercury
will directly measure the pressure in the pan.

_8

-14

—20
—22
_24
_26
-28
_30

FIG. 195.

361

CANE SUGAR.

After the pressure in the pan and the temperature of the boiling mass
have been determined by reference to the tables, the elevation of the boiling
point is found, and from this the apparent percentage of sugar in the boiling
mass is determined.

Zero

FIG. 196.

Instead of using tables, Claassen has devised a mechanical scale for
determining the apparent percentage of sugar. In Fig. 197, A, B and C are
three scales ; A and C are fixed and B is a sliding scale ; A is the vacuum
scale and C is the temperature scale ; C is graduated in equal divisions

362

THE CONCENTRATION OF THE SYRUP TO MAS8ECUITE.

170

Vacuum 1

B

•$

QQ

Temperature

I6O

QO

ISC

Sȣ-

91

24

90

-T=

— — •

T

140

88

V

25

I3O

86

26

84

82

120

80

27

110

28

=2

IOO

FIG. 197.

corresponding to the divisions of a thermom-
eter ; on A, opposite to the temperature
divisions on C, are marked the corresponding
pressures or vacua at which water boils. The
sliding scale B is graduated so as to connect
the elevation of the boiling point with the
amount of sugar present, on the same basis
as the divisions in the scale C. A deter-
mination is actually made as under.

The vacuum in the pan is 28*0 inches
and the temperature is 140° F. The zero on
the scale B is placed opposite 28*0 on the
scale A; the division on the scale C corre-
sponding to a temperature of 140-0° F. is
then noted, and opposite this on the scale B
is the division 89'9, i.e., the boiling mass
contains apparently 89 -9 per cent, of sugar.

It may at once be stated that it is only
bodies in solution that affect the boiling
point, and that sugar that has crystallized out
has no effect at all ; it is only then with
masses boiled string-proof that the apparent
sugar percentage of the whole mass is given ;
in other cases it is the apparent sugar per-
centage of the mother liquor. The scales in
the brasmoscope are calculated on a sugar
basis, and give only the apparent percentage
of total solids expressed as sugar, exactly as
the Brix spindle gives also apparent total
solids ; actually the non-sugar causes weight
for weight a greater elevation of the boiling
point than does the sugar, so that the brasm
oscope indication will always be higher than
the true total solids, and this will be the
more pronounced the impurer the mass that
is being tested.

Application of the Brasmoscope. — The
simplest instance of the use of the brasmo-
scope lies in its application to low products
boiled string-proof; here no sugar separates
in the pan as crystals, and the indications of
the instrument will now refer to the Brix*

Brix in what follows is used as synonymous with the true total solids.
363

CANE SUGAR.

of the whole mass in the pan. Suppose it has been found by experience that
a mass of 50 apparent purity gives the best results when boiled to an
apparent Brix, as indicated by the brasmoscope, of 90 ; when this factor has
once been determined it is an easy matter to boil all subsequent strikes of this
purity to the same elevation of the boiling point, and this can be done more
exactly with the aid of graduated instruments than by the sense of touch of
the most experienced sugar maker ; the illustration given above demands,
of course, that the nature of the non-sugar does not vary.

From the formula or table it follows that a massecuite of 50 purity con-
centrated to 80-86 Brix will give molasses of the same purity as one of 55
when concentrated to 82-44 Brix. The ratio between these two Brix is
82-44 -f- 80-66 = 1-0195. Hence the required Brix as indicated by the bras-
moscope is 86-5 X 1-0195 = 88-19, i.e., if a massecuite of 50 purity gives
molasses of 46 purity when concentrated to 86*5 Brix as indicated by the
brasmoscope, a massecuite of 55 purity will give molasses of the same purity
when concentrated to 88-19 as indicated by the brasmoscope,

The application of the brasmoscope readings to control the water content
of massecuites boiled to grain is complicated in that the instrument does not
give the Brix of the massecuite as a whole but of that of the mother liquor ;
what is required to be known may be expressed thus : What shall be the
Brix of the mother liquor in the pan at the moment of observation so that
on cooling exhausted molasses result ? And algebraically the problem can be
solved thus :

Let the solubility of sugar in molasses at a low temperature be s and let it
be s' at a more elevated temperature ; it is required to find what must be the
Brix when the solubility is s' so that the purity is m when the solubility is s.
Let x be the Brix of the molasses when the solubility of sugars is s.

Then

1 — x •=. water

* (1 — x) =. sugar
and

s (1 — x)

m •=. —± 1

x

whence

*=7^ C1)

Now let the solubility of sugar change to s1, all other factors remaining the
same.

The absolute amount of sugar in solution now is s1 (1 — x}, the water
and non-sugar remaining the same.

If the Brix be now denoted by x1,

364

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

For s put s -\- d, d being the difference in the solubility of sugar at the
two temperatures.

Then

1 -f- d — dx

But x has already been shown to be equal to

I

m 4- s
Making the substitution

s ds

d-\- —

*'= ^™ + s !!L + J- = 8~dmj (2)

7 4- /7 ds s -{- m — dm

m -\- s

As a numerical example let the solubility of sugar be 1*8 and let molasses
of 46 purity be required ; the Brix of these molasses will be from equation (1)

1-8 -h -46

Now let the solubility of sugar become 2 -5 so that d is -7. The Brix of
the molasses then is from equation (2)

100 x 2-5 - '? X -46 = 82-57

2-5 -f -46 — -7 x '46

Unfortunately the solubility of sugar in the hot mother liquor (sf in the
equation established above) in the pan can not be exactly known ; it is affected
by the temperature prevailing, by the presence of non-sugar and by the degree
of supersaturation ; now at the temperature 40° C at which it is customary to
cure massecuites boiled to grain and cooled in motion the solubility of sugar
in water is 2*38 and at the temperature 70° C which is approximately that of
the massecuite in the pan the solubility is 3*20 ; the ratio of these is 1-34 ;
previously the solubility of sugar in exhausted molasses was taken as 1*8,
at a temperature of 27° C ; between 27° C and 40° C the solubility of sugar
in water increases in the ratio I'll, and hence at 40° C the solubility of sugar
in molasses is taken as Ml X 1'8 = 1-998 and at 70° C 1-998 X l'34 = 2-68;
cutting off the decimals then the values of s and s1 in the equation established
above will be taken as 2-0 and 2*7.

Now owing to supersaturation the lowest solubility possible in the pan at
the temperature of 70° C will be 2-7 and it may be considerably higher.
Values of the equation

s 4- m — md

for values of s = 2-0, d= 0 to 1-3 (V = 2-7 to 4-0) and m=3S to 50
have been calculated and are given in the table below ; in the vertical column
on the left hand side are entered the solubilities of sugar in the molasses in
the pan ; in the horizontal caption are entered the values of m from 38 — 50 .

365

CANE SUGAR.

0

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Solubility of sugar

1

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366

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

the figure at the intersection of a vertical and horizontal line gives the degree
Brix of the molasses in the pan, so that when the solubility of sugar becomes
2'0 molasses of the purity in the column selected will result. As an example
the solubility of sugar at the moment of observation is 3*0 and it is desired
to obtain molasses of 40 purity when the solubility is 2'0 ; at the intersection
of the line 30 and 40 is the figure 84'82, i.e., the Brix of the molasses in
the pan must be 84*82.

As pointed out in dealing with the application of the brasmoscope to
massecuites boiled string proof, it is impossible to state beforehand what the
indication of the brasmoscope should be, and the brasmoscope indications must
be systematically compared with the actually recorded results in the factory.
When once the brasmoscope indications corresponding to molasses of a satis-
factory low purity are obtained, then it should be possible to reproduce those
conditions more exactly than can be done by the senses of sight and touch.

The process of exhausting rapidly low grade massecuites mentioned above
as ' reversed process ' would appear to be a scheme lending itself readily
to a very complete control, as it would only be necessary to determine the
proper concentration of the low grade massecuite before taking in the sugar
used as ' priming,' as has already been indicated when dealing with the
application of the brasmoscope to massecuites boiled string proof.

Control of the Supersaturation.— As the supersaturation rises
so also does the elevation of the boiling point ; when once the most favourable
degrees of supersaturation for the different periods of the process of concentra-
tion in the pan have been determined, they may be referred to elevation of the
boiling point, and it is thus possible always to boil the pan under equal
conditions. For example, suppose it is desired to work with a continuous
feed, and it has been found that, with a boiling point elevation of 20° C.
the best results are obtained ; the feed and steam valves are so set that this
elevation is maintained as indicated by the brasmoscope reading ; should a low
elevation be observed it is evident that syrup is being admitted too fast, i.e.,
the supersaturation is diminishing. Similarly the granulation and the bringing
up can be worked with a prearranged supersaturation as indicated and
controlled by the brasmoscope indication. Actually in the majority of cases
the skilled sugar boiler makes these observations by the senses of sight and
touch, and for these the brasmoscope substitutes a definite scientific relation.

Use of the Refractometer. — The methods by which the total
solids in sugar house products are obtained with this instrument are given in
Chapter XXIII. This instrument is particularly serviceable in determining in
a very short space of time the concentration of the massecuite in the case of
strikes boiled blank. The sample of material removed in the proof stick serves
for the determination, which can be made in two minutes. This instrument
gives a most valuable control over the whole process of pan boiling.

367

CANE SUGAR.

Special Treatment of Low Massecuites. — The time required
for a complete crystallization of low grade products may be shortened by dis-
tributing over the surface of the massecuites a quantity of sugar crystals
which are allowed to slowly fall through the massecuites ; the quantity of
crystals used is about 1 per cent, on the weight of the massecuite.

Crystallization in motion on a new basis has been applied in recent years
to low massecuites by means of air injection ; compressed air is introduced
at the bottom of the tanks containing massecuite by means of a rubber hose.
The treatment is begun after the massecuites have stood for 48 hours ; at first
they are treated daily, then twice a day, and eventually every three hours.

Calculation of Proportions of Syrup and of Molasses to
be used to obtain a Strike of prearranged Purity.- Let the

volume of the whole strike be unity and that part due to the syrup be x.
Then 1 — x is the volume due to the molasses. Let^? be the desired purity of
the strike andj98 and pm be the purities of the syrup and of the molasses.

Then p =. pt x + pm (1—x] ; whence x — * _P™

Example. — It is desired to obtain a strike of 65 purity from syrup of

80 purity and molasses of 45 purity.

65 — 45
The volume of the strike due to syrup is then gQ ^ = '571.

If the whole volume of the strike is 1000 cubic feet the pan will be filled
up to 571 cubic feet with syrup massecuite and the strike completed with
429 cubic feet of molasses. This calculation supposes that the percentage of
solids in the syrup massecuite before drawing over the molasses and in the
molasses are the same.

Eifect of Size of Grain. — The smaller the grain the larger is the
exposed surface and the greater the area of crystal surface that comes in
contact with the mother liquor within a given time ; hence the rate at which
the desaccharification of a mother liquor proceeds is greater in a small grained
massecuite than in one with larger crystals ; it is only however the time that
is affected, as the total amount of sugar that separates is solely determined by
the water content of the massecuite. In addition, with the larger exposed
area of crystal surface, there will be less chance of a deposit of fine or of false
grain, and for this reason a small grained massecuite can be safely cooled at a
greater rate than can a larger grained one.

Rapidity of Cooling.— The rate at which a body cools is within
certain limitations proportional to the excess temperature ; hence immediately
after striking the rate of cooling is greatest ; if the massecuite cools faster
than sugar can deposit, the coefficient of supersaturation increases, and there
is danger of the formation of fine grain due to the sudden deposit of crystals
from a very supersaturated solution, the sugar so depositing not forming on

368

THE CONCENTRATION OF THE SYRUP TO MASSECUITE.

crystals already present. It should be the object of the sugar maker to so
control the rate of cooling that the supersaturation does not increase, and that
the deposit of sugar keeps pace with the rate at which the massecuite cools.
The advantage of jacketed containers in a crystallization in motion process is
connected with the point explained above ; namely, that a means is provided
whereby the rate of cooling can be controlled.

Fig. 198.

Forms of Crystallizing: Tanks.— The receptacles in which the
massecuites are received in order to be cooled in motion are either U shaped
or cylindrical horizontal vessels ; they are constructed of boiler plate, and are
made either closed or open. Through the centre of the vessels passes a shaft
to which is attached the stirring apparatus ; motion is usually transmitted to
this shaft by means of a wheel and worm gear, the wheel being attached to

FIG. 199.

one end of the shaft ; the tanks are so arranged that one worm gears with the
wheels of the whole battery. The tanks are made either plain or provided
with a jacket, into which steam or water can be admitted, and thus control
the rate at which the massecuite cools. A. general form of crystallizing tank
is shown in Fig. 198.

369

24

CANE SUGAR.

Of special designs of crystallizers may be mentioned : —

RagOt and Tournour's. — This is shown in Fig. 199. The stirring
gear in this pattern is a hollow helical coil through which steam, hot water or
cold water can be passed. On one end of the shaft is a hollow shaft b, to
which is connected a steam or water distributing box c. The steam or water
passes into an annular space in the pipe I, thence by way of a pipe d to the
coils, returning through the pipe to the outlet/.

FIG. 200.

Hlich Crystallizer. — This is shown in section in Fig. WO. It con-
sists of a closed cylindrical vessel surmounted by a dome ; in this vessel are
arranged the tubular elements aa which may be used as heating or as cooling
surfaces ; the path of the stream or water is shown by the arrows ; the stirring
device is shown at b.

REFERENCES IN CHAPTER XVII.

1. Beet Sugar Manufacture, p. 149.

2. Bull. 16, Agric. H.S.P.A.

3. S. C., 309-311.

4. Sucrerie Beige, July, 1898.

370

CHAPTER XVIII.

THE SEPARATION OE THE CRYSTALS.

The finally concentrated product of the juice (massecuite) consists of a
magma of sugar crystals and a thick viscid solution of sugar, and of all the
bodies present in juices. The crystals are separated from this magma by
means of machines known as centrifugals or hydro-extractors. Formerly —
and to some extent still — the molasses were allowed to drain from the
massecuite, which was packed in hogsheads with perforated bottoms.

Receptacles for, and Transport of, Massecuites. Tank
System. — The first massecuites are emptied into shallow wooden or iron
tanks arranged on the basement; from these tanks directly, or after cooling,
the massecuite is dug out and carried by hand to the centrifugals ; this-
arrangement is now but seldom found for first sugars, but still remains very
common for low sugars, which may be stored for periods up to a whole year.

Tank Tramway System. — The massecuites are emptied into tanks-
holding up to 100 cubic feet, which run on tram lines and are hence
capable of being wheeled to the centrifugal battery, where their contents are
emptied by manual labour ; alternately these tanks may discharge into a pitr
whence the massecuite is elevated by a chain or magma pump ; or the tanks-
may be on an upper floor and may discharge their contents by gravity.

Small Can System. — The massecuite is discharged into cans holding
about 500 Ibs. ; these cans are transported by means of trolleys, elevated
by means of an hydraulic lift, turned bottom upwards and their contents-
discharged by compressed air, a small hole being arranged in the bottom
wherein is inserted the nozzle of a pipe communicating with an air compressor.
This system has been and is still largely used, and in many ways is very con-
venient ; it demands, however, extensive floor space.

Gravity System. — The pans are built on a high floor and discharge
into receivers, whence the massecuite flows by gravity to the pug mill of the
centrifugals.

Compressed Air System. — The massecuites are received in closed
vessels and are conveyed in pipes by compressed air to the centrifugals \.
this method is very clean, but demands a fluid massecuite or one thinned with
molasses. These two last schemes are used frequently with crystallization in
motion.

371

CANE SUGAR.

Th.6 Centrifugal Machine. — A centrifugal machine consists
essentially of a vertical cylindrical perforated basket, which is caused to
revolve at a high rate of speed ; within the perforated basket is fixed a wire
gauze strainer, containing from 400 to 500 perforations per square inch. The
revolution of the basket throws the magma of crystals and molasses against
the side of the basket ; the molasses and a portion of the crystals pass through
the gauze, and the great portion of the crystals are retained ; without the
perforated basket is a casing which catches the molasses and directs them by a
spout into the gutter.

Types of Centrifugals. — Centrifugals were perhaps introduced
into the sugar industry in 1849, by Dubrunfaut, and now a large number of

FIG. 201.

types are to be found ; mainly they fall into two classes, fixed bearing pattern
and suspended pattern ; again they may be divided into under and over-driven
machines, or according to the method of driving, direct coupled, friction cones,
belt, electric, or water drive.

Fixed Bearing Friction Cone Machine. — In Fig. 201 is
shown a view of this type of machine ; / is the spindle revolving in two
brasses, i and /, the lower brass i being fixed in the bottom of the monitor
outer casing k and the upper one j in the cross piece of the frame h, which is
supported on and bolted to the outer case ; the basket I is secured to the
spindle by the nut g, screwed down on the cone m, which rests on the bottom
of the basket ; a collar n on the spindle prevents any downward movement.

372

THE SEPARATION OF THE CRYSTALS.

Motion is transmitted to the machine by a belt drive on the pulley c, and by
the friction cones a and b ; the driving cone a is of steel, and the driven cone b of
mill board ; the driving spindle o is carried on two bearings, the cones being
kept in contact by the pressure of the spring e on one end of the spindle ; the
cones are thrown out of gear by means of the screwed piece d moving the
spindle outwards against the pressure of the spring.

Belt-driven Pivot Machine.— In Fig. 202 is shown a type of
pivot under-driven machine, which, equally with the above, is common on the
Continent of Europe and wherever the influence of Continental engineers is
felt. The basket a is fixed to the spindle c, which is supported by the footstep

FIG. 202.

bearing /, and the collar formed by the iron bars e ; these bars are screwed
up against pieces of indiarubber d. whereby the shock ' of the machine is
partly absorbed. The machine is driven by belt drive on the pulley g.

Weston Suspended Centrifugal.— All machines of the types
above described use a large part of the power supplied in keeping the
revolving basket in a fixed position. In 1852 David Weston invented and
made in the Hawaiian Islands the first suspended centrifugal which has since
become the standard pattern in cane sugar factories ; beet factories in Europe
were (and still are) slow to adopt this pattern. In Fig. 203 is shown a section
of the Weston type of centrifugal machine as arranged for belt drive. SB is
the suspending block firmly bolted to an overhead beam or framing CF ; EB
are elastic buffers resting on the block SB, and above this is suspended from
the elastic buffers the spindle IS by means of a top nut and washer; this
spindle oscillates with the machine, but does not revolve ; at BB is shown the
bottom revolving bearing; at OS is shown the outer revolving spindle attached

373

CANE SUGAR.

C.F.

176.

FIG. 203.

374

THE SEPARATION OF THE CRYSTALS.

to the driving pulley DP. The perforated basket is shown at B, and the outer
casing at 00 ; and sugar is discharged through a circular aperture at the
bottom of the basket, kept closed when necessary by the valve DV, which
slides up and down the outer spindle ; the bottom part of the outer spindle
forms an oil bath. The elastic buffers are an essential feature of this type of
centrifugal. The massecuite will from time to time assume different centres

267

FIG. 204.

of gravity ; instead of attempting to restrain the machine in a fixed position
this system allows a certain freedom of movement.

A solid spindle has in recent years been generally substituted for the
hollow spindle, and after several failures ball bearings have been successfully
adapted to this machine ; in Fig. 20!j. is shown the upper part of a belt-driven
machine embodying these improvements.

375

CANE SUGAR.

Hepworth Suspended Centrifugal.— The Hepworth suspended
centrifugal differs from the above in that the whole machine is suspended ;
referring to Fig. 205, it will be seen that a is the ball of a ball and socket
joint formed in the bracket m, from which pass three or four rods k which
support the outer casing d of the machine ; the bracket n is so formed as to
make a reservoir of oil ; the spindle carrying the revolving basket g is shown

FIG. 205.

at h ; this spindle works in two bearings seen at o and p ; the brake is seen at
c, and the brake band at I ; cast on the bottom of the outer casing are lugs on
which are placed indiarubber bands e passing over the fixed brackets /; these
indiarubber bands are for the purpose of controlling the movements of the
machine, and at the same time allowing a certain freedom of movement.

376

PLATE XVIII.

4062

FIG. 207

PLATE XIX.

RC&W.29I

FiG. 209.

THE SEPARATION OF THE CRYSTALS.

Motive Power for Centrifugals. — Until recent years a belt
drive was the usual method of driving centrifugals but latterly many installa-
tions have adopted a water or electric drive. In Fig. 206 is shown a view of
an electrically driven spindle as made by Messrs. Pott, Cassels and Williamson.
The lettering is as under: — C inside spindle, D intermediate spindle, H top
plate of motor case, K armature, L magnet coils, M brake, 0 commutators,
P brushes, Q, driving disc, ft friction arms, S pulley, T brake pulley. On
switching on the current the magnet coils pull off the brake and the armature

being loose on the outer spindle
immediately revolves at a high
speed and gradually communicates
motion to the spindle V by means
of the friction arms which are
pressed out against the pulley.

In Fig. 207 (PLATE XVIII.)
is shown a view of the electric-
driven spindle as made by Messrs.
Watson, Laidlaw & Co. The let-
tering is as follows : — C brushes,
D commutator, E motor spindle,
F field coils, G armature, L friction
shoes, N worm and wheel, E,
brake, T inner revolving spindle,
U stationary sleeve, Y outer
revolving spindle, Z switch.

In Fig. 208 is given a view
of the water-driven machine of
Messrs. Watson, Laidlaw and Co.
This type of machine has in
recent years been very extensively
adopted. The head of water
necessary to drive the machine is
obtained from a double acting
pump ; no large supply is needed,

as after discharge from the Pelton wheel fitted on the outer spindle, the water
flows back to the supply tank of the pump. Two jets are supplied, and after full
speed has been obtained, one is automatically cut off; if it is desired to
get up speed slowly one jet only is used, an advantage in curing low-grade
products.

The motor and centrifugal head of the water-driven machine of Pott,
Cassels and Williamson is shown in Fig. 209 (PLATE XIX); the reference being
as follows: — 38 centrifugal spindle; 33 ball-bearing; 35 rubber buffers; 29

188

FIG. 206.

377

CANE SUGAR.

4148

Fm. 208.
378

THE SEPARATION OF THE CRYSTALS.

brake pulley ; 30 brake band ; 37 bracket carrying the centrifugal suspended
from the I beam 40; 3 and 4 motor case; 10 ball-bearing; 2 water wheel;
5 hemispherical caps upon which impinge the water jets 6 and 7 of which 6
is the accelerating and 7 is the maintaining jet ; 39 waste pipe ; 25 governor
controlling the supply of water when full speed has been obtained ; 27 wire
rope links connecting motor to centrifugal.

These machines are made in pairs with an interlocking gear so designed
that only one of a pair of machines can be accelerated to speed at one time.

In plants of earlier date where the whole battery of centrifugals was
driven by belt drive, the whole ratio of gearing between engine and machine is
from 300 to 400 to 1 ; with such an arrangement any variation in the
speed of the engine is multiplied in the centrifugal and means of varying
the speed of a machine or of distributing the power according to the demands
on it are impossible ; with the interdependent water and electrically driven
machines the power supplied varies according to the demand ; thus with the water
drive two jets are employed both of which act when the machine is starting
and when the effort is greatest ; afterwards only one jet is in action. A similar
principle is embodied in the electric driven machines ; this action is of use
too in curing low grade sugars which often are found to purge best when speed
is got up slowly ; cost of up-keep and freedom from danger are also points in
favour of the direct motor driven types.

Size of Basket. — Within the last decade the size of basket has
increased from a standard size of 30 in. to a maximum of 48 in. increase,
beyond which it is limited by the size and strength of men ; indeed, a 48 in.
machine can only be cared for by a big labourer ; with increase in size of
machine, a decrease in the number of revolutions (but not in the peripheral
speed) follows. The smaller machines are run at 1,200 to 1,500 revolutions
per minute, and the larger at 800 to 1,000.

Capacity of Machines. — A 30 in. suspended Weston machine will
produce from 1,600 to 2,0001bs. of dry sugar per hour from a typical first
masse cuite ; a 42 in. machine will produce up to 4,000 ; masse cuites however,
vary so much, even when boiled from syrups of apparently the same composi-
tion, and so much depends on the craft skill of the sugar boiler and curers,
that estimates of capacity are of little value ; this is especially so in the case
of low sugars ; in addition, the type of sugar made, raw or washed, influences
very much the capacity.

Washed Sugars. — The sugars generally made on plantations are
shipped to refineries for further treatment and are not washed in the centri-
fugal basket ; in Mauritius and Java, however, large quantities of white
(^plantation refined') sugars are made for the Indian market and these sugars

379

CANE SUGAR.

FIG. 210.

are also produced in quantity where a large local demand exists as in Natal
and South American countries. The special methods of clarification have
been described in Chapter XTII. ; in curing these sugars water and then steam
are used.

In many factories specializing in
these sugars the writer has seen the
water thrown into the basket from a
saucepan or other simple receptacle. A
more efficient scheme is shown in Fig.
210 \ the water leaves the nozzle in a
fine spray and is evenly distributed
over the sugar; the pipe is jointed at b
so that the part be may be swung out
of the basket during charging. After
the water has been used, steam is admitted to the interior of the basket. In
Mauritius steam at 60 Ibs. per square inch pressure is led to the basket from
the main steam pipe by means of a flexible hose ; the action of the steam is
two-fold ; the elevation of temperature makes the molasses more limpid, and
condensation of the steam and water already present dissolves out some crystal
sugar. Superheated dry steam does not dissolve sugar, and hot air would have the
the same effect, but some solution and temporary loss of sugar is necessary so as
to entirely remove the film of molasses and to obtain a really high class article ;
actually a massecuite which would give say 64 per cent, of raw sugar will
give 50 per cent, of plantation refined. The sugar thus obtained remains in
the basket as a hard compact mass and before bagging has to pass through a
sugar breaker or mixer; dry sugar ' polarizing 99-7 ' at 28° C. may be obtained
with this scheme.

Classification of Syrups. — When sugars are washed the last run-
nings are of high purity and should be collected separately. One method
consists of the use of two gutters as shown in Fig. 211 ; when the molasses

^ — • ^ proper is running it is

directed to gutter b, the
spout c being in the position
shown ; when water or
steam are being used the
spout c is raised so as to
occupy the position shown
by the dotted lines and the
runnings pass into the
gutter a. Owing to the
slowness with which mo-

FIG. 211.
lasses flow, only a very partial separation occurs.

280

THE SEPARATION OF THE CRYSTALS.

A large number of devices to obtain the separation of a rich and poor
molasses have been patented ; the main idea is the interposition between the
outer monitor casing and the wall of the basket of a partition removable at
will ; when the effluent from the basket impinges on the partition it passes to
one gutter, and when the partition is removed the effluent strikes the monitor
casing and passes to a second gutter.

Patterson's apparatus, which is but one of many recent inventions to this
end, is shown in Fig. 212. It consists of two cones attached to the basket,
top and bottom, so that their bases nearly meet in the centre. These cones
AA deliver the molasses from the annular opening F, and not all over the
casing like an ordinary centrifugal basket. Besides the usual gutter in the
bottom, another narrow and deep gutter H is placed inside the casing for the

FIG. 212.

washings ; its top being below the level of the annular opening formed by the
cones. A movable guard B suspended by four chains from an equal number
of pulleys E controlled by a hand wheel 1) on the outside, hangs between the
basket and the washings gutter. The weight of the movable guard is
balanced by a spring attached to the hand wheel. Thick copper wire cloth
suspended over the washings gutter prevents splashing ; the fixed guard M
protects the gearing from * spill,' and the blocks P secure the apparatus in
case of excessive oscillation.

The centrifugal is charged and spun with the movable guard raised, as
shown in Fig. 212. The molasses, caught on the cones attached to the basket,
are at once discharged by the centrifugal force and conducted by the movable
guard to the usual gutter in the bottom, leaving the cone surfaces clean and
ready for immediate washing. When washing commences, the guard is

381

CANE SUGAR.

lowered by the hand wheel out of range of the annulus, the washings are caught
on the wire cloth and conducted out of the centrifugal by the special gutter.

Another very complete but expensive process consists in the use of two
sets of centrifugals in one of which the original molasses are removed ; the
sugar is discharged, repugged with syrup, and again cured with water and
steam washings ; the second purgings return to first sugar manufacture and
the first purgings are treated separately.

FIG. 213.

Conveyance of Cured Sugar. — In some instances the cured
sugar is filled into bags directly from the baskets ; but in the majority of cases
it is elevated to an upper floor of the factory, whence it is, after becoming
partly air dried, directed down shoots into the bags in which it is packed,

The elevator in most common use is shown in Fig. 213 ; it consists of an
endless belt carrying a number of buckets ; the belt can be arranged to work
at any angle ; the dry sugar is carried on one of the systems described below
to the elevator, and falls directly into the buckets.

882

THE SEPARATION OF THE CRYSTALS.

The transport of the sugar from the centrifugals to the elevator is effected
by means of a belt, a * grasshopper? or a spiral conveyor. Belt conveyors,
which are but little used, consist merely of endless belts running on
pulleys. The grasshopper conveyor, Fig. 21/j., is a suspended trough supported

FIG. 214.

on flexible inclined blades ; a to and fro motion is transmitted to the trough
by means of a belt, pulley and connecting rod, whereby the sugar is jerked
forward. The spiral conveyor, Fig. 215, consists of a trough in which rotates
a steel spiral, the sugar being earned forward by the action of this screw. Of
these systems, the writer prefers the grasshopper, as in the screw conveyors a
certain loss occurs, due to crushing of the grains from the action of the
screw.

Where the sugar is bagged directly from the basket, the bags are carried
to the storage room on an endless slat conveyor.

Storage of Sugars. — It is often necessary to store sugars for long
periods, whereby deterioration sometimes occurs; the evidence connecting
deterioration with bacterial action is collated in Chapter XXVI. It may be said
that two postulates are necessary for deterioration, sufficient moisture and
presence of bacteria. Deerr and Norris2 found that with 1 per cent, of water

FIG. 215.

infected sugars did not suffer deterioration ; a 'factor oj safety ' due to the
Colonial Sugar Refining Co. of Australia, and which has become widely known,
is that the water should not be more than half the non-sugar, or when

,-TT; - 1 — • — r- — < '333, the sugar will not deteriorate.
100 — polarization

383

CANE SUGAR.

Although sugars may be dry on storing, they may take up water after-
wards and in the presence of bacteria suffer loss. This deliquescence is due
entirely to the film of molasses and is connected with the following causes ;
to the presence of hygroscopic salts such as acetates occurring when stale or
damaged or diseased canes are worked up or when an excess of lime has been
used in the presence of much glucose ; to the presence of chlorides introduced
from the soil or irrigation water, as was noticed by Wray so long ago as 1848 ;
to decomposition products formed by overheating.

Protection of the sugars can be partially obtained by the construction of
a close and tight warehouse, and the use of an interior proof paper bag is also
recommended in some quarters.

In beet sugar districts stress is laid on packing the sugars only after
thorough cooling and on an alkaline reaction ; this last cause cannot affect
cane sugars since they are almost invariably acid as regards phenolphthalein.

FIG. 216.

Infection of Sugars. — The studies of Lewton-Brain and Deerr3
on Hawaiian sugars showed that the forms of bacteria met with are heat
resistant and are not destroyed in the usual process of manufacture ; hence a
juice originally infected will afford an infected sugar ; the possibility of
obtaining sterile syrups, &c., is one of the points (in the writer's opinion) in
favour of the use of superheat clarification. There are many other points of
infection, of which the most prominent are the return of low grade sugars
obtained from exposed coolers, and the use of dirty water at or about the
centrifugals ; the tin pail so often seen as a receptacle for water, into which a
filthy rag is dipped which then serves to wipe down the spindle and about the
machine, is a source of infection which may result in serious deterioration.
Here of all places absolute asepsis should be aimed at, an end approximately
obtained by the use of condensed water continually renewed and not allowed
to stand, combined with the application of formalin as a bactericide.

384

THE SEPARATION OF THE CRYSTALS.

Sugar Driers* — Sugar driers are used to dry white plantation refined
sugars and also find a use in drying the rather low grade sugars resulting from
crystallization in motion schemes. A view of a form of drier is shown in
Fig. 216 ; it consists of an inclined cylinder a a which is caused to revolve
about a longitudinal axis, power being received from a belt at the pulleys
b ; inside the cylinder are a number of shelves which throw the sugar about
in passage ; the wet sugar enters through the shoot c and leaves at d ; hot
air heated by passing over the steam heated coils at e passes through the
cylinder and leaves at /under the influence of a fan. In the Hawaiian islands
the sugar occupies about five minutes in its passage through the apparatus
and reaches a temperature of about 180° F., the moisture falling from about
1'5 per cent, to about '5 per cent.

Druelle Say Process.4 — However carefully the massecuite is
boiled, a certain amount of fine grain is formed which passes through the cen-
trifugal mesh ; this process aims at recovering this loss through the agency of
filtration ; the molasses containing the fine grain are passed through filter
presses of conventional design, the cake of fine grain which forms in the
presses being dissolved in the thin juice.

Experimental Study of Centrifugals. — The various questions
that arise with regard to the treatment of massecuite in the centrifugal have
been carefully studied by Geerligs5. He determined first from actual factory
experiments the yield in the same massecuite when boiled to different degrees
of concentration and found that although more sugar separates out in close
boiled than in more open boiled massecuite, the yield in crystals is not
augmented, as more water is required to remove the more viscid molasses ; on
the other hand, there is a limit to the amount of water which should be left ;
he found the best results were obtained when the true water content was 8 per
cent, to 9 per cent., corresponding to an apparent water content of 5 per cent,
to 7 per cent.

He found too, that when impure massecuites were cured hot, direct from
the pan, practically the same amount of crystals was obtained as when
cured cold, but that with pure raassecuites considerably more crystals were
obtained when cured cold. This result is of course due to the sugar in the
impure massecuite, when cooling, separating as small grain ; in the pure
massecuite of less viscidity, to the sugar separating on grain already
present.

As a general rule the amount of sugar present as crystals is very much
the same in all first massecuites of both high and low polarization, and it is
the form and shape of the crystals that control the yield in the centrifugal.
This point is of such interest that the following table due to Geerligs is
reproduced here, where it will be plainly seen on inspection that the purer

385

25

CANE SUGAR.

massecuites gave a larger yield, not because more sugar was present as
crystals, but because a larger proportion of the crystals were recovered.

Polariz-
ation.

Glucose.

Water.

Quotient
of
Purity.

Crystal-
lized
Sugar.

Sugar in
the
Syrup.

Crystals
obtained

Crystals
lost.

Sugar
obtained.

Per cent.

Per cent.

74-1

11-07

9-02

78-06

61-62

12-48

51-1

10-11

54-8

78-9

8-99

776

83-58

68-22

10-68

58-81

9-41

64-3

79-0

8-47

7-82

83-72

69-09

9-91

55-28

13-81

58-8

8M

6-93

9-2

87-23

66-96

14-14

60-0

6-96

62-85

84-1

4-81

8-11

88-62

67-81

16-29

64-1

3-71

66-1

84-2

3-20

9-77

90-28

64-13

20-07

62-01

2-12

67-5

84-8

2-74

8-23

88-93

62-93

21-87

59-46

3-47

3-40

86-7

1-83

7-58

93-45

67-10

19-60

66-80

0-30

74-1

That the size of the crystals has much to do with the removal of molasses
is self-evident, when it is remembered that the larger the grain the less is the
area of contact for the molasses, and consequently the latter are the more
easily removed ; Geerligs demonstrated this by allowing syrup to drain from
massecuites in which the size of the grain varied; his results are given
below : —

Diameter of the grain

m.m.
3-0
2-0
1-5
1-0
0-5

Syrup run off;
grms.

300
265
200
115
20

Mixtures of 600 grms. sugar crystals and 400 grms. of syrup, as indicated
above, were allowed to drain for three days, the larger the diameter of the-
crystals the greater the quantity of syrup run off.

This experiment has however a double interpretation, for the rate at
which a syrup is desaccharified depends on the area of crystal surface in
contact with molasses, so that apart from questions of purging, a small grain
and large surface is often required ; the processes followed and kind of sugar
produced are the factors which control the size of crystal to be made.

The general rules for the treatment of massecuites may then be
summarized. Impure massecuites with purity under, say, 80-81, give best
results when not boiled too close and when cured hot ; purer massecuites may
be boiled to a less water content and should be cured cold ; as even a grain a&
possible should be made. This is a point where the skill of the pan boiler is
shown, and is really of very great importance ; a juice which, in the hands of
one pan boiler, gives a massecuite from which 56 per cent, to 58 per cent, of
crystals are recovered may, when boiled by one more skilful, give a recovery
of 60 per cent, to 62 per cent.

386

THE SEPARATION OF THE CRYSTALS.

Composition of Sugars. — The isolated examples of analyses often
found quoted in text books are of little interest, as not necessarily denoting
the average of the district whence they come.

The figures published by the Java Experiment Station would indicate
an average content of over 97 per cent, in the refining grades ; the per cent, of
water is not stated. Hawaiian sugars are of similar polarization and contain
about '8 per cent, water. Similar sugars are doubtless made in other
progressive sugar districts; muscovados or common process sugars are of very
variable quality, but about 90 per cent, sugar would be a fair average. Low
sugars, i.e., under 95° polarization, have now a very restricted output.

The other bodies present, glucose, ash and organic non-sugar, vary within
wide limits ; in refining crystals neither the glucose nor ash often reach 1 per
cent., bnt they amount to 2 per cent, and over in low grades. The plantation
refined sugars, produced in quantity in Mauritius and Java and elsewhere,,
often polarize as high as 99*6 at 30°C., and are hence almost pure ; they
contain only traces of ash, glucose, water, and organic non-sugar.

REFERENCES IN CHAPTER XVIII.

1. I.S.J., 98.

2. Bull. 21, Agric. H.S.P.A.

3. Bull. 9, Path. H.S.P.A.

4. I.8.J., 99.

5. 8. C.y 390.

387

CHAPTER XIX.

MOLASSES.

Geerligs' Theory of Molasses.* — The chief factor in the
formation of molasses was formerly considered to be the viscidity of the
syrups preventing free movement of the sugar molecules ; this theory fitted in
with the knowledge that in heet molasses the sugar content was higher than
in a saturated aqueous solution containing the same amount of water; in
•cane molasses the reverse is generally the case. This observation is alone
sufficient to invalidate the older theory, known as the mechanical theory of
the formation of the molasses. The whole subject has been the object of a
classical research by Geerligs1.

Geerligs introduces his subject by a discussion of the methods of analysis
of molasses, and shows —

1. The method of direct polarization gives results that may be too high
or too low.

2. Clerget's method gives results agreeable with those obtained by deter-
minations of glucose before and after inversion.

3. The glucose present has a lower levo-rotation than that due to pure
invert sugar.

4. The glucose present is not inactive at 88° C., the temperature at which
the activity of invert sugar vanishes.

Of earlier experimenters Gerard and Laborde2 and also Miintz and Hulze3
found glucose from cane sugar inactive ; Gunning4 and Meissl5 found the
rotation of glucose in cane molasses the same as for invert sugar.

Herzfeld6 and Wehne7 found the glucose to consist of varying quantities
of dextrose and levulose. The last result is the one to which Geerligs came ;
in his results it is always the dextrose which is present in the greater propor-
tion, and accordingly it is quite possible for the mixture to be optically
inactive. After having made complete analyses of a number of molasses,

* When "Sugar and the Sugar Cane" was published, Geerligs' theory was only to be found
described in journals ; since then he has detailed his theory in his treatise 'Cane Sugar and its
Manufacture ' to which reference may be made for a complete account.

388

MOLASSES.

Geerligs reviews the results of earlier investigators. Marschall8 determined
the effect of the presence of salts that occur in beet molasses on the solubility
of sugar ; he found that sugar was more soluble in the presence of either
acetate, butyrate, carbonate or citrate of potash, but that all other salts had no
effect, or diminished the solubility. Felz9 adhered to the mechanical theory,
holding that the viscidity of molasses prevented crystallization; this
mechanical theory is not accepted by Geerligs who found that the maximum
amount of sugar crystallized out from solutions made thick with glue or
agar-agar, the viscosity being much greater than in molasses.

Gunning4 formed artificial molasses by admixture of pure sugar and
solutions of alkaline organic salts ; he found that potash salts formed with
sugar syrupy combinations which did not crystallize, and deduced the formation
of a saccharate of potash; he gave 6-1 as the molasses-forming coefficient of
potash, i.e., one part of potash (as KOH) prevents 6'1 parts sugar from
crystallizing; for acetate of potash the figure would be 1-5 allowing only half
the potash to affect the sugar, the other portion remaining as an acid salt.

It had been previously stated by nearly all writers that glucose was
melassigenic; the coefficient had been placed by Pellet10 at 0'60, by Flourens11
at between 0*30 and 1-0, Degener12 declaring that glucose had no direct
melassigenic property but that the acid products of its decomposition inverted
sugar. Geerligs made a series of experiments to test this statement. As a
source of glucose he used honey in which the dextrose and levulose are present
in about the same proportion as in molasses ; he thus was able to prepare a
series of solutions in which the water and sugar were constant but the glucose
varied from nothing up to 25 grms. ; the sugar present was always 25 grms.
and the water 7'5 grms. It was found that the sugar crystallizing out was
always the same and that the glucose had no effect and hence was not
melassigenic. Geerligs next tried the effect of the presence of acetate of
potash and the combined effect of this salt and glucose ; he found that one
part of acetate of potash per 25 of sugar had no effect, with two parts the
effect was noticeable, and was very marked with five parts ; but when one part
acetate of potash and ten parts glucose were present per 25 parts sugar the
combined effect was anti-melassigenic, i.e., more sugar crystallized out than
from water alone, and it was not till five parts acetate of potash and ten parts
glucose were present that the combined effect was melassigenic. In later
papers on the subject Geerligs returns to the effect of glucose on the crystalliza-
tion of sugar and suggests that glucose forms with organic potassium salts
easily soluble syrupy bodies which absorb water and render the proportion of
sugar to water lower than normal; this point is entirely supported by his
analyses when the ratio of glucose to alkalinity of the ash as potash is
considered, the alkalinity of the ash as potash being a measure of the organic
salts present, such a salt as acetate of potash giving on incineration carbonate

389

CANE SUGAR.

of potash. As a general and well-marked rule, Geerligs found that when the
ratio of glucose to alkalinity is low, i.e., when there is much glucose and
little alkalinity, the solubility of sugar in molasses is greater than when the
reverse is the case. A further point brought out by the analyses is that when
a large proportion of undetermined constituents occurred the solubility of the
sugar was low, the undetermined bodies being probably substances of similar
constitution to glucose and acting in the same way.

To further test the results found on a study of natural molasses Geerligs
formed artificial molasses out of sugar, purified honey and various salts ; the
salts employed were the acetates of potash, soda and lime, the apoglucinates*
of the same bases, inorganic salts such as the chlorides and sulphates, and
mixtures of organic and inorganic salts. The method of experiment was that
the calculated quantities of sugar, honey, salt and water were put into large
flasks, sterilized at 100° C., plugged with cotton wool and allowed to crystallize.
The following results were obtained : solutions with acetates only produced no
inversion, those with apoglucinates produced little inversion ; solutions with
inorganic salts always inverted and the inversion was greatest when the
quantity of glucose was greatestf ; when organic salts and inorganic salts were
present the inversion was much less than in the immediately preceding case.
The results already obtained with regard to the solubility of sugar in the
presence of other bodies were completely confirmed and in addition it was
found that the sugar-precipitating power of the organic salts was greatest in
the order lime, potash, soda.

The inversion of sugar by the combined effect of glucose and salts was
then investigated ; it was found that glucose per se had no inverting effect but
that in the presence of salts, organic or otherwise, it had. Geerligs explains
these experimental phenomena in these words, ' ... the entire action of
molasses forming is explained by the assumption that loth sugar and glucose, and
those products of decomposition of the latter which resemble caramel, have a
tendency to combine with the bases of the salts, and hence to a certain extent act as
•acids.'* This statement is in entire accord with the theories of Van't Hoff
expressed symbolically as

Glucose -f- Salt "^I^L Glucosate -f- Acid

i.e., if glucose and salt occur together in solution they are mutually to a
certain extent dissociated ; the same equation holds equally for saccharose.

In accordance with this equation, if saccharose and an organic salt are
present together, they are both to a certain extent dissociated, and the
saccharose forms with the base a very soluble hygroscopic compound, and hence
is explained the abnormal solubility of sugar in beet molasses, which contain
but little glucose. When glucose is present along with saccharose, the glucose

* The decomposition products formed on heating glucose with lime,
t cf. Article 'Inversion,' in Chapter XIII.

390

MOLASSES.

possessing an aldehyde group is more readily split up, and forms with the bases
similar compounds to the above, and extracting water has the effect of lowering
the solubility of saccharose, as is the case in cane molasses. When the car-
bonatation process is used the glucose is in great part destroyed, and saccharose
is found more soluble in carbonatation than in defecation molasses. When
glucose and an organic salt are present their mutual dissociation forms free
acid and causes inversion, but the inverting power of organic acids being
small the inversion is not great. When glucose and an inorganic salt are
present the same reaction occurs, and the inversion is greater for the reverse
reason.

When glucose, organic and inorganic salts are present, the combined
effect is chiefly that due to the organic salt, and the effect of the inorganic
salt is modified.

The causes tending towards the formation of molasses may be summarized —

1. The presence of non-sugar requiring water for its removal, such water
carrying away sugar.

2. The formation of molecular compounds consisting of sugar and organic
salts, chiefly potash salts.

3. Inversion under the influence of acids as when working with phos-
phoric acid and under the combined influence of glucose and salts, chiefly
inorganic salts.

4. An excess of lime acting on glucose, originally present and giving rise
to organic salts, which then act as in (2) and (3).

5. Viscosity of syrups resulting in formation of fine grain which passes
through the centrifugal.

6. Careless pan boiling, resulting in fine grain, requiring much water in
the centrifugals.

As tending to prevent the formation of molasses Geerligs indicates
but does not recommend the use of baryta, inclining more to the car-
bonation process, and when the usual defecation process is used he recommends
one to —

1. Use as little lime as possible in defecation but of course enough to get
a good clarification.

2. Prevent by rapid working and cleanliness every source of acidity,
because if juices get sour they require fresh quantities of lime to neutralize
the acid and therefore fresh quantities of salts are produced.

3. If any excess of lime has been used, remove it by the use of phos-
phoric or sulphurous acids which decompose some of the organic acids and
precipitate the lime.

391

CANE SUGAR.

4. Extract the salts from the after-products by putting the latter under
water.

The decomposition of glucose in the carbonation process gives rise to
large quantities of organic salts and hence in carbonation molasses the sugar
solubility is high ; this is counterbalanced by the less quantity of molasses
formed.

In later papers on the same subject Geerligs13 defines molasses as — "a
hydrated combination between sugars and salts, which can not be broken up
by evaporation, and therefore cannot give off sugar in a crystallized form."
He regards the proportion of sugar in molasses as controlled chiefly by the
reducing sugars present and writes — "There is no question of the solubility
of sucrose at all, but only of the composition of a combination which contains
on an average 55 per cent, sugar, 25 per cent, salts, and 20 per cent, water.
If there is a big proportion of reducing sugar in that portion of 55 per cent.,
then there is little left for the sucrose ; if on the contrary the percentage of
glucose is small, the syrupy combination contains much sucrose.

"It is evident that in my theory there is no place left for negative
molasses-formers ; the non-sugars, especially salts, combine with sugars and it
depends entirely on the mutual relation of sucrose and reducing sugars
whether much or little reducing sugars will enter into the combination."

Hawaiian Molasses. — Peck14 examined a number of Hawaiian
molasses and did not find any relation to obtain between glucose and
ash; he observed however that molasses containing much sucrose also con-
tained much gum. By gum Peck means the residue obtained after breaking up
the lead precipitate by hydrogen sulphide, filtering off the precipitate of lead
sulphide and evaporating the filtrate to dryness ; he showed that molasses
purified by precipitation of the gums with alcohol on concentration afforded a
notable crop of crystals. It does not follow that the bodies precipitated by
lead and by alcohol are the same, and indeed Hazewinkel17 has shown that the
lead precipitate consists largely of organic lead salts, so that much lead
precipitate implies also much organic acid and hence in Geerligs' theor}' a high
solubility of sucrose; further along with the gums precipitated by alcohol
much ash also comes down and the crystallization of sugar may have been due
(in part at least) to the removal of the ash.

Composition Of Molasses. — The only detailed series of analyses
of molasses according to district of origin with which the writer is acquainted
are those due to Geerligs in Java and to Peck in Hawaii ; between these there
does not appear much difference and in a very rough way molasses may be
regarded as a material containing about 20 per cent, water, 30 per cent, sugar
and very variable quantities of reducing sugars, ash, organic acids, caramel and

392

MOLASSES.

gums. The composition of the molasses is of course controlled by the initial
composition of the juice and this point, as regards the sugar content of the
molasses, is discussed in greater detail below. Actually the limits of the com-
position of molasses may be put down as

Water 15 per cent. — 25 per cent. ; total solids 75 per cent. — 85 per cent. ;
sucrose 25 per cent. — 40 per cent. ; reducing sugars 5 per cent. — 30 per
cent. ; ash 7 per cent. — 15 per cent. ; gums 5 per cent. — 3 per cent. ; organic
non-sugar 10 per cent. — 20 per cent. ; purity 35 to 50.

The lower amounts of reducing sugars are found in the Hawaiian Islands
where the juices are exceptionally pure and contain very little reducing sugars
in the juices, sometimes as low as '2 per cent. ; the higher amounts are found
in Louisiana and Demerara molasses where the reducing sugars in the juices
may rise to 2 per cent, or more ; other districts will have intermediate
quantities.

Exceptionally low purities of 20 or under are sometimes reported in
Louisiana, but Browne,15 who has had exceptional opportunity to examine
such molasses, has stated that these are due to inversion or to errors of
analysis.

The Bearing of Glucose on the Sucrose Content of
Molasses. — In constructing his theory of molasses Geerligs made certain
experiments the results of which, he thus summarizes, " . . show
that glucose of itself possesses no molasses-forming power, nor can it serve to
make more sugar crystallize out." Accepting, then, that glucose is an in-
different body its effect on molasses can be algebraically developed as under.
Molasses of whatever origin are of composition, water 20 per cent., solids 80
per cent. ; a typical beet sugar molasses obtained in the absence of glucose is
of composition, sugar 45 per cent., solids not sugar 35 per cent., water 20 per
cent. ; to such a molasses let 20 parts of an indifferent body, such as glucose,
be added; the mixture will now be of Brix (80 X 20) -j- 120 = 83'33; let x
be the amount of water to be added to reduce the Brix to 80 ; then

120 4- x ~ 2 ' w^ence x — 5< The new f°rme(l mixture will, when reduced
to 80° Brix, be of composition, sugar 36 per cent., glucose 16 per cent., non-
sugars 28 per cent., water 20 per cent., purity 45 ; such a composition is that
of a typical cane molasses. Proceeding on this argument the following table
of the composition of molasses is capable of construction, beet molasses of the
composition given above being taken as a basis of calculation ; to this
molasses quantities of glucose 3, 5, 7 &c., per 100 original molasses being
added, and the composition of the mixture being then calculated back
to 80° Brix.

393

CANE SUGAR.

Glucose
added
per 100
original
molasses

Sugar
per cent.

Glucose
per cent.

Non-
sugars
per cent.

Water
per cent.

Sugars
per cent.

Purity.

Glucose,
Non-
sugars.

0

45-0

0

35-0

20-0

45-0

56'2

0

3

43-4

2-9

33-7

20-0

46-3

54-2

•08

5

42-3

4-7

32-9

20-0

47-0

52-9

•14

7

41-4

6-4

32-2

20-0

47-8

51-7

•20

10

40-0

9-0

31-0

20-0

49-0

50-0

•29

12

39-1

10-4

30-4

20-0

49-5

48-9

•34

14

38-3

11-9

29-8

20-0

50-2

47-9

•40

16

37-4

13-3

29-3

20-0

51-1

46-7

•46

18

36-7

14-7

28-6

20-0

51-4

45-9

•51

20

36-0

16-0

28-0

20-0

52-0

45-0

•58

24

34-6

18-4

26-9

20-0

53-0

43-2

•68

28

33-3

20-7

25-9

20-0

54-0

41-6

•80

32

32-1

22-9

25-0

20-0

55-0

40-1

•92

36

31-0

24-8

24-1

20-0

55-8

38-9

1-03

40

30-0

26-7

23-3

20-0

56-7

37-5

1-14

44

29-0

28-3

22-6

20-0

57'3

36-2

1-25

48

28-1

30-0

21-9

20-0

58-1

35-1

1-37

52

27-2

31-5

21-2

20-0

58-7

34-0

1-48

56

26-1

32-9

20-2

20-0

59-7

32-6

1-66

64

25-0

35-5

19-4

20-0

60-5

31-2

1-83

72

23-7

37-9

18-4

20-0

61-6

29-6

2-06

80

22-5

40-0

17-5

20-0

62-5

28-1

2-28

88

21-4

41-9

16-7

20-0

63-3

26-7

2-50

96

20-5

43-6

15-9

20-0

64-1

25-6

2-74

The Addition of Glucose not a Precipitant of Cane
Sugar. — The idea has unfortunately come about in many quarters that
Geerligs' theory of molasses implies that the addition of glucose will cause
sugar to crystallize ; there is no ground for this deduction anywhere in his
theory. High glucose certainly implies a low purity in molasses but at the
same time the addition of glucose will lower the initial purity of the juice;
the fallacy of this deduction can be best shown by an actual example.

394

MOLASSES.

Following on the previous sections a juice containing 14 per cent, sugar, 2 per
cent, non-sugar and no glucose will give a molasses of 56'2 purity ; the initial
purity of the juice is 87 '5 ; applying the formula for available sugar

(Chapter XXV.) in its simplest form, namely, extraction ="^7} — 7— ;» the sugar

t/ \ /

to be obtained is 81*6 per cent. Now to this juice let one part of glucose be
added; the juice will now be of purity 82-35 and molasses of purity 47*50
maybe expected; the extraction will now be 80-6 per cent., a lower result
than obtained before the addition of the glucose.

If, however, instead of glucose solids not sugar be added, a purity of 56-2
may be expected and with initial purity of 82'35 an extraction of 72'5 will
result.

This calculation goes to show that of all the impurities present in a cane
juice the glucose is the least harmful, but that its addition lowers the possible
recovery.

Geerligs' theory has even been distorted us implying that inversion of
part of "the sugar would increase the yield; it is hard to see how such a
meaning could be read into it.

The Glucose : Non- Sugar Ratio.— According to the position
taken up by the writer, the purity of the waste molasses is controlled by the
glucose : non-sugar ratio, and as the proportion of glucose increases so also
does the total sum of the sucrose and glucose. With beet sugar molasses where
glucose is not present, the sucrose amounts to about 45 per cent, and such a
condition is sometimes found approximately in the Hawaiian Islands : where
as often happens, in Java for example, the glucose or non-sugar are in approx-
imately equal proportions, the sum of the sucrose and glucose amounts to about
55, a figure which may rise to 60 and over in the juices resulting from extra
tropical canes found in Louisiana and from sea level equatorial canes as found
in Demerara. No absolute concordance can be expected, as the effect of the
nature of the non-sugar is very great ; concurrently, as shown in Geerligs'
theory, with the presence of much organic potassium salts a high purity is to be
expected ; this observation is in line with Peck's analyses where he found much
lead precipitate correlated with a high purity since Hazewinkel17 has shown
that the lead precipitate consists largely of organic salts.

The following table of analyses of Hawaiian molasses by Peck and Deerr
wherein all the analyses are calculated to a water content of 20 per cent, does
not show the regularity to be expected from the above line of reasoning.
Certainly with high glucose the sum total of the sugars tends to increase but
the purities do not correspond, and indeed the last three analyses quoted, where
a high purity might be expected due to the low glucose, have purities below
the average. The nature of the solids not sugars probably exercises a big

395

CANE SUGAR.

influence, although when these are kept constant as already shown a fair
agreement follows; all that can be said is that a high initial glucose non-
sugar ratio probably will result in molasses of low purity, the reverse also
holding.

Viscosity as affecting Molasses Formation.— Geerligs
found that sugar crystallization was the same in a medium thickened with
agar-agar ; viscosity, however, tends towards sugar losses, as in viscous
media the crystals formed are small and to obtain free purging a lower
concentration is required; these causes are really outside the matters discussed
above which refer to a saturated molasses free from fine grain.

Recovery of Sugar from Molasses.— So far as the writer is
aware the schemes used to some extent in beet sugar factories are not employed
in cane sugar factories ; they are, however, touched on below.

Sugar.

Glucose.

Non-Sugar.

Water.

Sugar and
Glucose.

Purity.

Glucose :
Non-Sugar.

36-6

22-9

20-5

20-0

59-5

45-7

1-12

31-5

17-9

30-8 20-0

59-2

38-9

•58

4M

14-8

24-1 20-0

55-9

51-1

•61

40-3

15-4

24-3

20-0

55-7

50-4

•63

42-3

13-3

24-4

20-0

55-6

52-9

•54

34-5

20-8

24-7

20-0

55-3

43-2

•84

35-1

19-9

25-0

20-0

55-0

43-9

•79

37-0

17-4

25-6

20-0

54-4

46-2

•68

39-2

14-7

26-1

20-0

53-9

49-6

•56

36-6

16-9

26-5

20-0

53-5

45-7

•63

35-3

18-0

26-7

20-0

53-3

44-1

•67

43-9

6-8

29-3

20-0

50-7

54-9

•23

35-2

15-0

29-8

20-0

50-2

43-9

•61

32-6

17-4

30-0

20-0

50-0

40-7

•58

35-8

13-6

30-6

20-0

49-4

44-7

•44

34-6

14-3

31-1

20-0

48-9

43-2

•46

38-4

10-4

31-2

20-0

48-8

45-5

•33

35-5

13-0

31-5

20-0

48-5

44-4

•41

41-7

6-4

31-9

20-0

48-1

52-1

•20

37-2

9'1

33-7

20-0

46-3

46-3

•27

37-4

8-9

33-7

20-0

46-3

46-7

•26

33-7

11-2

35-1

20-0

44-9

42-1

•32

37-4

16-8

25-8

20-0

44-2

46-7

•65

32-3

10-9

36-8

20-0

43-2

40-4

•30

36-9

6:2

36-9

20-0

43-1

46-1

•17

34-9

7-2

38-9

20-0

42-1

43-6

•19

32-3

8-8

38-9

20-0

41-1

40-4

•23

396

MOLASSES.

Osmosis. — It follows from the above sections that if the salts could be
removed from an exhausted molasses, the conditions of solubility of the sugar
would be altered and a further portion would be capable of crystallization.
About 1850 a method of effecting this was worked out by Dubrunfaut. The
principle of his process known as osmosis is as follows : If a concentrated solu-
tion of any soluble body be separated from a weaker solution or from water by
a semi-porous membrane, such as parchment, the two solutions will pass through
the membrane until they are of the same concentration. The rate at which
this osmosis or diffusion takes place is not the same for all bodies ; inorganic
salts such as potassium chloride diffuse much faster than sugar ; hence if a
solution of molasses be separated by a parchment membrane from water, a
greater proportion of salts will pass through the membrane in a given time than
sugar. An osmogene is an apparatus to effect this separation ; it consists of a
structure similar to a filter press in which are held a series of wooden frames,
shown in elevation in Fig. 217. Between each frame are placed sheets of

Q/'

0-"'

FIG. 217.

parchmentized paper, pierced at the angles to correspond with the apertures
shewn at A, B, C, D, and at A', B/, C', D', in Fig. 217. At b and c in the
one frame, and at a and d in the other, are small channels establishing commu-
nication with the interior of the frame. If, then, water enters at B and
molasses at D, the water will flow along the canal formed by the openings B
and into the interior of the frames by the channels b, and the molasses will
similarly flow by way of D and d'. The water will discharge itself along the
canal formed by the openings C and c, and the molasses along that formed by
the openings A l and a '. There is thus a continual flow of molasses and water
separated by a sheet of parchment. The water which leaves the apparatus
now charged with a proportion of molasses is called water of exosinose, and it
contains roughly about half the salts originally present in the molasses.
Although this process has been largely used in times past and is still to a
certain extent employed in beet sugar factories it is financially unsuccessful ;
the large size of the osmogenes required (500 square feet diffusion surface only

397

; SUGAR.

being sufficient to treat three tons of molasses in twenty-four hours), the
extreme dilution of the osmosed molasses, the expense of evaporation, and the
small extra yield of sugar entirely discounting the monetary value of the
process.

Substitution Processes. — The Steffen and Scheibler substitution
processes although they are not worked in cane sugar factories deserve a
passing notice. With bases cane sugar acts as a weak acid and forms
saccharates, those of potassium, lime, strontia, baryta, lead and iron having been
studied. With baryta only one saccharate is known: — 012H2201 jBaO j
it is formed as a crystalline precipitate when a mixture of a solution of baryta
and sugar is heated ; it dissolves in 41 parts of water at 15° C.

With strontia two saccharates are formed; on mixing two molecular
proportions of strontia with one of sugar in a boiling solution the bibasic

saccharate

C12H220112SrO.

results and on cooling this body decomposes into the monobasic saccharate

C12H22011SrO
and strontia.

With lime, four saccharates are formed ; the monobasic saccharate

C12H22011CaOH20

is formed by mixing molecular proportions of lime and sugar. This body is
soluble in the cold, and is precipitated from aqueous solution by alcohol.

The bibasic saccharate

is formed by mixing a double molecular proportion of lime with one of sugar.
It is soluble in 33 times its weight of cold water.

The sesquisaccharate

2C12H220113CaO

is obtained by pouring an excess of milk of lime into a dilute solution of sugar
and evaporating to dry ness.

If a solution of the bibasic saccharate be boiled it is decomposed, giving
the tribasic saccharate

sugar and the bibasic form.

On these reactions are based the commercial processes for the extraction
of sugar from exhausted molasses.

The first processes were those of Scheibler (1865) and Seyferth (1872).
In them molasses and slaked or quicklime were intimately mixed in a
pug mill, and the resulting magma of saccharate and molasses washed with
alcohol to remove the salts and organic non-sugar, and the purified saccharate
mixed with the juice and carbonated. Many mechanical improvements were
introduced by Bodenbender and Manoury, the former obtaining the saccharate

398

MOLASSES.

in the form of cakes and the latter as grains. In both cases denaturated
alcohol (duty free) is used, the alcohol being recovered for use. Over 90 per
cent, of the sugar in the molasses is extracted at an average cost of 2s. for
every 100 Ibs. of molasses treated.

The original substitution process of Steffen eliminates the use of alcohol
and is based on the behaviour on boiling of the mono- and bibasic lime
saccharates. The five operations in the process are : —

1 . Formation of a soluble bibasic saccharate in the cold.

2. Transformation of the bibasic saccharate into sugar and insoluble
tribasic saccharate by boiling.

3. Separation by filtration of the tribasic saccharate.

4. Regeneration of the mother liquors by the addition of fresh molasses.

5. Periodic reduction of the mother liquors.

In outline the different processes are worked as follows : —

1. Molasses diluted to 11°- 12° Balling are mixed with continual agitation
with powdered quicklime in the proportion of one part sugar to one of lime ;
the mixture is then filtered to remove scums.

2. The filtrate is heated for ten minutes in autoclaves to a temperature of
105°C.

3. The tribasic saccharate formed in (2) is filtered, the cakes washed with
boiling water, and the saccharate employed in place of lime in treating the
raw juice.

4. The mother liquors coming from (3) are used to dilute a further
quantity of molasses to a sugar content of 6 per cent.

5. After a time the mother liquors are so charged with impurities as to
render them too impure to return ; they are then treated separately, two
operations sufficing to almost completely exhaust them. The mother liquors
are returned about 25-30 times, after which the process commences afresh.

The cost of this process is only about Is. per 100 Ibs. of molasses, a
recovery of over 90 per cent, of the sugar in molasses being obtained.

The second more recent process of Steffen considerably modifies and
simplifies the above process.

It consists of three parts : —

1 . Preparation of a very pure finely divided quicklime.

2. Formation of a tribasic saccharate insoluble in the cold.

3. Extraction and purification of the saccharate.

In preparing the quicklime, a very pure non-siliceous limestone is selected
which is burned out of contact with the fuel (see Chapter XI ) ; the burnt
lime is broken up in a stone-breaker and passed through a series of sieves to
obtain it in the necessary fine state of sub-division.

399

CANE SUGAR.

In the second operation the molasses diluted to a density of 10°- 12°
Brix are cooled down to a temperature lying between 0° C. and 13° C.,
generally to one of 6° 0., and quicklime added in small quantities about
10 Ibs. at a time until 210 parts of lime are added per 100 of sugar;
during the whole operation the molasses are continually agitated and the tem-
perature is not allowed to rise above 13°C. ; at the end of the process,
which lasts about three-quarters of an hour, there is obtained a pasty mass,
consisting of a mixture of tribasic saccharate and slaked lime.

The third operation consists 'of separating the saccharate by nitration and
washing with cold water ; the nitrate which contains practically all the im-
purities is rejected, the washings being used to dilute a further quantity of
molasses; the purified saccharate is either used in place of lime on raw juices
or is treated separately by carbonation. The cost of working this process is
only about half that required for the older Steifen process.

The discovery of large deposits of strontianite in "Westphalia opened the
way to the use of this material in extracting sugar from molasses.

Two processes both due to Scheibler are in use.

1. Bibasic Process. — In this process three equivalents of strontia to
one of sugar are added to a hot diluted molasses, and the saccharate which
forms is separated from the mother liquors by nitration and washed with a
10 per cent, solution of strontia; all these operations are done when still warm.
In order to decompose the saccharate, it is placed in vessels set up in a battery
through which is passed water at a temperature of from 4°C. to 15°C., the
water containing 2 per cent, of strontia; by these means the bibasic body is
decomposed into the monobasic body and strontia ; this operation takes about
forty-eight hours. A solution of sugar still containing strontia passes out of
the diff users and is treated by carbonation.

2. Monobasic Process. — In this process a solution of strontia is mixed
with molasses, the temperature not being allowed to rise above 20°C. ;
the monobasic body formed is separated by_filtration and treated to a carbona-
tion process.

The Disposal of Molasses. By sale as suck. — In certain
places the sale of molasses to distillers or for direct consumption forms a part
of the routine ; in some cases, particularly in the muscovado process followed
in Barbados, this procedure is very profitable since fancy prices are still to be
obtained for these grades of molasses. Considered from the point of view of
the agricultural chemist, nothing can be said in favour of this scheme as it
entails the absolute removal from the soil of much valuable plant food,
particularly in the form of potash. With the very pure juices found in the
Hawaiian Islands the molasses amount to about 20 per cent, of the sugar
shipped, a figure rising to as much as 40 per cent, in the case of the impure

400

MOLASSES.

juices found in Demerara, and elsewhere; molasses on an average contain
about 4 per cent, of potash, so that the sale of the molasses implies the
removal from the soil of from 18 to 36lbs. potash per ton of sugar shipped.

Sale as Cattle Food. — The sale of molasses as cattle food was originated
on the large scale by Mr. O. Hughes, who observed that the finely divided
interior pith of the cane was capable of absorbing large quantities of molasses,
affording a product which could be shipped in bags ; this product was put on
the market under the name of ' molascuit.'

The manufacture of this article requires plant of a very simple nature,
which is generally capable of being placed so as to fit in with existing
arrangements. The method of manufacture in a certain West Indian factory
is described below. The megass, before the manufacture of molascuit was
started, discharged itself from a scraper elevator on to the cross carrier which
conveyed the megass in front of the furnaces ; a sifter of one-eighth inch mesh
and of 8 ft. X 4 ft. dimensions was interposed between the elevator and cross
carrier ; the megass fell on to this sifter to which an oscillating motion was
given by an eccentric driven off a convenient engine ; in the passage of the
megass along the sifter to the cross carrier a number of the finer particles fell
through and these were directed down a shoot on to the flue wall of the
boilers. The brickwork on the top of the flue was replaced by sheet-iron
plates and a drying surface obtained for the megass; after the megass had been
dried it was again sifted through a sifter of mesh one thirty^second of an inch.
Kefuse molasses was mixed with the doubly sifted megass powder in the pro-
portion of seventy parts of molasses to thirty parts of megass ; the molasses
were concentrated to 85° Brix before mixing and a much more even product
was obtained when hot molasses were used ; before bagging, the molascuit was
allowed to cool ; the mixing was performed in a * Carter ' kneading machine.
The double sifting is of importance so as to eliminate the larger particles of
megass, especially splinters, consisting of the hard and indigestible outer rind.
In other installations more elaborate machinery is employed, and in large plants
the use of a drier similar to those used for drying sugar would be advisable
both for the megass and for the final product. The keeping qualities of the
product depend very largely on the extent to which it is dried.

Molasses feeds are not a complete food and are very deficient in proteid,
the percentage of nitrogen being only about '15 percent. ; hence they require
supplementing with other material, especially in the case of working animals.
In Mauritius the seeds of an acacia-like shrub, Luccena glauca, are used in com-
bination with molasses, and in Louisiana the ration of molasses is frequently
balanced with cotton seed meal. T. U. Walton18 advises a ration of 151bs. of
molasses to a 1,270 Ib. horse, and states that for working horses this quantity has
no undue fattening effect, that the salts in this quantity of molasses are not
•deleterious, and that sugar is generally an efficient substitute for starch.

401

26

OANE SUGAR.

Cotton Seed
Blood, Meal, Corn,
Cereal. Corn, Oats. Oats.
Molasses. Molasses. Molasses,

Extracted
Rice,
Bran.
Molasses.

Megass.
Molasses,

15-38 . .

11-90 ..

12-23

. . 8-40

. . 13-98

1-11 ..

3-15 . .

2-30

.. 0-83

.. 0-90

9'52 . .

6-27 . .

7-79

. . 9-70

.. 511

12-98 ..

14-30 ..

12-78

. . 13-00

.. 5-64

16-13 ..

12-75 ..

6-41

. . 14-00

1-94

15-01 . .

21-65 ..

19-43

. . 5-50

. . 55-94

29-87

29-98

39-06

. 48-56

16-49

The following analyses of molasses feeds are due to Browne19 : —

Water

Fat

Ash „', \/ .. ..

Fibre . . ......

Protein

Sugars

Other carbohydrates.

Manufacture of Alcohol. — In the West Indies and the Argentine
generally, and often in Peru, Natal, and Australia, the distillery forms an
integral part of the sugar factory, a potable spirit known as rum being manu-
factured in large quantities. The sale of alcohol leaves all the fertilizing
elements in molasses available for return to the soil, and hence this scheme
has much in its favour. At the time of writing (1910) the anticipated large
production of denatured alcohol from molasses in the U.S.A. has not
taken place.

Use as Fuel. — Molasses are occasionally used as fuel to supplement
that afforded by the megass ; if the ashes are returned to the soil a portion of
the plant food is recovered but the nitrogen is lost for immediate use. The
fuel value of molasses is discussed in Chapter XX.

Return to Soil. — On irrigated plantations molasses can be returned
to the soil at small expense ; in Mauritius they are often incorporated with
the composts of manure. Ebbels and Fanque20 have produced evidence that
the sugar in the molasses aids the nitrogen-fixing organisms in their work,
resulting in an increase in the nitrogen content of the soil, and in increased
crops. Their results are extremely suggestive and are a strong argument in
favour of this method of disposal, but more evidence is required as to the
specific action of sucrose and glucose upon the nitrifying, denitrifying and
ammonifying organisms of the soil before the indiscriminate use of molasses
can be recommended.

Boname21has also detailed the results of experiments showing that the effect
of molasses is greater than might be expected from its composition ; he mentions
that in Mauritius a litre of molasses (3 Ibs.) is often applied to each cane hole
(3000 holes to an acre) and states that this amount might be decreased with
advantage so as to spread the available supply over large areas.

On the other hand experiments made by Peck22 have shown that the
continued addition of glucose to soil bacteria in vitro retards the activity of
the nitrifying and ammonifying organisms and accelerates that of the
denitrifying races.

402

MOLASSES.

REFERENCES IN CHAPTER XIX.

1. S. C. 284-292; 311-313.

2. Zeits. fur Ruben., 1876, 399.

3. „ „ „ 1878, 735.

4. Saccharimetrie in accijns.

5. Zeits. fur Ruben., 1879, 1040.

6. ,, „ „ 1885, 967.

7. „ „ „ 1888, 785.

8. ,, „ ,, 1870, 339; 1871, 97.

9. „ ,, ,, 1870, 337; 1871, 167.

10. „ „ „ 1879, 806.

11. Jour. des. Fab. de Sucre, 1880, 40.

12. Zeits. fur Ruben., 1881, 514.

13. I. S. J., 113-114.

14. Bull. 18, Ayric. H.S.P.A.

15. Bull. Assoc., 1897, 1086.

17. Arch., 1908, 53.

18. H. P. M., Sept., 1905.

19. L. P. xxxiv., 236.

20. Jour. des. Fab. de Sucre, 1909, 2.

21. Annual Report. Stat. Agron. Mauritius, 1909.

22. Bull 34, Agric. H.S.P.A.

403

CHAPTEE XX.

MEGASS AS FUEL.

The battery of boilers and its connections form one of the most important
parts of any factory, and are of peculiar interest in a sugar works, in view of
the evaporation produced by the steam here generated, in addition to that
required to supply motive power for the engines ; efforts to economize steam
within the factory are in great part useless unless economy is also practised in
the combustion of the fuel. The subject of boilers, as such, is a special one
of its own, and its discussion is quite outside the limits of a work such as the
present ; only a few points of special interest in the sugar factory are here
mentioned.

Boilers. — In general boilers may be divided into a number of classes,
such as external and internal fired boilers ; the Lancashire, Cornish and
marine boilers fall into the latter class, and these are quite unsuited for use
with megass and other low grade fuels. All boilers used with such fuels are
externally fired, and are (in comparison with coal and fuel oil fired boilers)
provided with large external combustion chambers.

The boilers in use in sugar factories are almost entirely of the multi-
tubular class, and these are divided into the smoke tube type, where the
heated gases circulate within the tubes, and the water tube where they pass
externally to the tubes.

The Smoke Tube Multitubular. — The smoke tube multitubular
boiler consists of a cylindrical shell of length usually not less than twice the
diameter; sizes 14ft. x 7ft., or 12ft. X 6ft are frequently met with. The
boilers erected at the Puunene Mill of the Hawaiian Commercial and Sugar
€ompany are 20 ft. X 7 ft., and this size is commonly used in the Hawaiian
Islands ; so great a length is objected to by some engineers on the ground that
the part of the boiler remote from the furnace is very ineffective, but the
results in fuel economy in the Hawaiian Islands .are such as to leave no doubt
in the writer's opinion that such objections are ill-founded.

In the end plates of the shell are drilled a number of holes into which
are expanded tubes, generally about four inches in diameter ; these tubes form
the greater part of the heating surface. A boiler seven feet in diameter will
have about 120 such tubes, and if fourteen feet long will have approximately
1,800 square feet of heating surface ; increasing the length to 20 feet will
give a heating surface of 2,600 square feet.

404

MEG-ASS AS FUEL.

The Water Tube Multitubular. — In the water tube multitu-
bular boiler the water is contained within the tubes, the products of combustion
circulating without the tubes. The forms of water tube boilers most frequently
met with in sugar factories are the Babcock & "Wilcox, the Stirling, the
Climax, the Hazleton and the Porcupine boilers.

Water tube boilers have been largely erected in Demerara, in Cuba, and
in the West Indies ; in the Hawaiian Islands, and in Java, however, the
practice has tended towards the smoke tube multitubular, although water
tubes are not uncommon in those districts.

405

CANE SUGAR.

Choice of a Boiler for a Sugar Factory.— Many years ago
the late Hugo Jelinek wrote : " In a sugar factory, a type of boiler is to be
chosen which has a large water capacity, so as to have always a provision of
heat for unequal consumption of 'steam in the factory."

On broad lines the writer's experience
has led him to endorse this view, and hence
to prefer the smoke tube multitubular, in
preference to the water tube, although
many experienced engineers hold an
opposite view. As far as economy in fuel
goes, the question of the boiler is not a
dominant one, and economy is chiefly a
matter of furnace design and careful
control of the combustion of the megass.

The water tube boilers have the
advantage of being built in large units,
of being adapted for high pressure, and
of being capable of raising steam quickly,
owing to their small water capacity;
because of this small water capacity,
however, any sudden load such as starting
a pan with cold syrup may cause a sudden
drop in pressure. Although it is for many
reasons inconvenient to work at two
pressures, a battery of water tube boilers
.at high pressure, supplying steam to the
•engines, and of smoke tube boilers at low
pressure, supplying steam to the evapora-
tors is a scheme that has much to be said
in its favour.

Megass Furnaces.— In Figs.
.218 and 219 are shown views of the
Dutch oven type of megass furnace ; this
type is largely used in Mauritius, in
Louisiana, in Java, in Mexico, and in the
Hawaiian Islands. In the diagrams the
boiler is seen at e\ the direction of the
products of combustion is first along the bottom and sides of the boiler, back
through the tubes, and out to the smoke box, and thence to the main flue. In
Figs. 220 and 221 is shown what is known as the Abel* type of megass furnace,
and is one largely used in Demerara. From the overhead shoot megass falls on
the fire bars at b ; the gases formed on combustion impinge on the arch at e.

FIG. 219.

406

MEGASS AS FUEL.

The air necessary for combustion enters at /, the space h forming a hot air
reservoir ; the ashes are removed at i ; the boiler is shown at c. The passage
of gases is first through the tubes, thence to the smoke box A, back along the
sides and out underneath the boiler to the main flue g. In this design the flue
gases pass three times along the boiler, as opposed to the two way pass in the
Dutch oven setting.

The Godillot furnace, Fig. 222, is a furnace of the Dutch oven type. The
megass enters at b, being propelled forward mechanically by the screw c ; the
fire bars are arranged to form three sides of a pyramid, shown at d ; air enters
at e, and /is an aperture for viewing the combustion.

407

CANE SUGAR.

The essential difference between the Dutch oven and Abel type of furnace
is the size of the combustion chamber ; the first furnaces which the writer
met with in his experience of the cane sugar industry were of the latter typey
and he learnt that these large combustion chambers were thought necessary to
obtain a complete combustion of the megass, and to avoid loss through the
presence of carbon monoxide in the flue gases ; with more extended experience
the writer saw factories with the Dutch
oven type of furnace working with extreme
fuel economy, and with better results than
others where the Abel type was in use.
Kadiation from the heated brickwork of
the furnace is surely one of the principal
sources of heat loss, and being proportional
to the exposed area will tend to become
very great in furnaces of exaggerated
length, which the writer has seen as long
as 28 feet from the face plate of the boiler
to furnace door; in addition, the greater
the mass of brickwork the greater is the
opportunity for cold air to leak in through
cracks in the masonry.

Stoking of Megass.— In recent
factories the megass is fed to the furnaces
by schemes mechanically as efficient as
those used for automatically firing coal;
a diagrammatic view of such a scheme is
shown in Fig. 223 ; megass direct from the
mill is delivered to a scraper carrier a a ;
this carrier is arranged to run in a direction
at right angles to furnaces ; over each fur-
nace is placed a sheet iron hopper b b and
over the mouth of this is a shutter c c, the
position of which is controlled from the
platform d d by means of a cord; the megass
is carried forward by the scrapers e e, the
quantity falling into the hopper being
controlled by the position of the shutter ;
// are two toothed cylinders revolving
inwards which serve to feed the megass

FIG. 221.

down the shoot; any surplus megass is directed on to the platform dd by
the shoot gg and is, when required, fired by hand through the fire box
door hh.

408

MEGASS AS FUEL.

Relation between Cane ground and Requisite Heating:
Surface, etc. — The writer has had access to essential data on these point*
as they occur in a large number of well equipped modern factories and as a
result has concluded that no average datum can be given, the variation in
factories, all of which were working well, being so great. In the following
table ' cane ' means the short tons of cane ground in 24 hours ; 1 2 square feet
heating surface in a smoke tube and 10 in a water tube are taken as the equiva-
lent of one horse power ; all surfaces are expressed in square feet : —

Ratio of

Horse power to Cane

Heating surface to Cane

Grate surface to Cane

Grate surface to heating surface

Maximum.
2-4 : 1
24 : 1
1

FIG. 222.

As shown in greater detail in another section, the thermal value of a pound
of megass of fixed water content is sensibly constant, and hence it would
appear reasonable that a fairly constant ratio of heating surface in boilers and
hence of horse power would obtain ; actually, the smallest variation in this
ratio does obtain and the writer thinks that a ratio of heating surface to cane
of 18 : 1 is ample and representative of good modern practice.

On the other hand, however, there is no reason for expecting any
uniformity in the ratio between grate area and heating surface ; this will of
course depend on the intensity of draught, a smaller grate area being sufficient
under forced or induced draught than under natural draught.

As will be explained in greater detail in a subsequent section, the weight of a
cubic foot of megass from varieties (or even in different seasons from the same

409

CANE SUGAE.

variety) varies within large limits; hence a ratio which may be quite satis-
factory in one factory will be totally inadequate in another. The writer has
frequently observed that when the White Transparent cane was being milled
in Demerara the megass accumulated, but the supply could not be burned fast
enough on the existing grate area to maintain the supply of steam. This
difficulty, which may become a great deal more serious than a mere incon-
venience, could in the writer's opinion be overcome by the installation of an
additional furnace wherein megass would be fired only when occasion arose.

FIG. 223.

If this difficulty is really due to differences in the weight of a cubic foot of
megass, its cure is surely to be found in increased grate area rather than in

increased heating surface in the boilers.

; _ ; 11 . ; ' • . 1 ". ..

Thermal Value of Megass. — The combustible bodies present in
megass are fibre, sugar, glucose and details of other organic bodies ; the fibre
consists of cellulose proper, and xylan or wood gum. The heats of combustion
of these bodies as determined by Stohlmann and Langbein3 are, cellulose, 7533
B.T.U., sugar, 7120 B.T.U., glucose, 6748 B.T.U. per Ib. Taking these heats
of combustion as a basis, and assuming that the fibre has the same fuel value

410

MEGA8S AS FUEL.

as the cellulose, it is possible to calculate the thermal value of a megass ; thus,
a megass of composition fibre, 42 per cent., sugar, 9-666 per cent., will afford,
on complete combustion, -42 X 7533 + -0966 X 7120 = 3851 B.T.U. per Ib.
for the fibre and sugar alone, to which must be added that due to the glucose
and other organic matter ; if this be taken as y1^ that due to the sugar, the
gross thermal value of the megass will be 3920 B.T.U., and per unit of dry
matter, supposing the megass contains 47 per cent, of water, 7396 B.T.U.
The heat of combustion of megass of different origin has been experimentally
determined by a number of workers. Geerligs4, whose results are discussed
more fully in another section, found the heat of combustion, per Ib. of dry
matter, to be sensibly constant ; his extreme values in B.T.U. are 8249 and
8514, with a mean of 8381 ; Burwell5, in Louisiana, obtained a mean value of
8325, with extremes of 8289 and 8384. These values are considerably higher
than would be obtained on calculation on the lines exemplified above ; actually,
then, it will be sufficient, under average conditions, to accept a fixed value of
8350 B.T.U. per Ib. of dry matter in a megass.

Products of Combustion of a Megass.— Each pound of carbon
on combustion requires a theoretical minimum of 2-67 Ibs. oxygen, a quantity
supplied by 12-03 Ibs. of air, the remainder, 9-36 Ibs., being nearly all nitrogen ;
at a temperature of 84° F. this quantity of air occupies 165 cubic feet. The
combustible elements in megass contain hydrogen and oxygen in the same pro-
portion that they exist in water, so that in calculating the air required for
combustion only the carbon need be taken into account. Of the bodies
present in megass, cellulose contains 44*4 per cent., xylan 45'4 per cent.,
sugar 42-1 per cent., and glucose 40-0 per cent, of carbon, so that from the
analysis of a megass its carbon content can be found. In actual determinations
Geerligs found megass to contain from 46 82 per cent, to 4 8 -45 per cent.
carbon, and from 6'30 per cent, to 6- 67 per cent, hydrogen on the dry ash free
material ; as an average then, per Ib. of dry matter, a megass may be taken
as containing 46-5 per cent, of carbon, and 6-5 per cent, of hydrogen, allowing
that the dry matter contains 2 per cent, of ash.

Per Ib. of dry matter, then, the products of combustion of a megass will be
Due to carbon '465 X -7-= 1*705 Ibs. carbon dioxide.

1 8
Due to hydrogen -065X--= '585 Ibs. water.

Due to nitrogen of air . . -465 X 9*36= 4 '352 Ibs. nitrogen.

Fuel Value of Megass as influenced by Variety.— In

" Sugar and the Sugar Cane" (page 280) it was stated that it was a matter of
clinical observation that the megass from different varieties of canes exhibited
very different values as fuel, and that this difference could not be accounted for by
low fibre content of the cane or yet from the analysis of the megass. Similar

411

CANE SUGAR.

observations have apparently been made in Java, and the matter has been
exhaustively enquired into by Geerligs4, a summary of whose results is given
below.

1. Actual determinations of the thermal value of the megass from
different canes showed that the calorific value calculated to dry weight varied
but little, and that the differences were entirely insufficient to account for the
variation experienced in factory work. Of the samples examined by him the
calories per kilogram of dry megass varied from 4583 to 4700.

2. The elementary composition of the ash free megass from different
canes was determined, and those examined were found to give nearly identical
results ; expressed as per cents, of the dry ash free material, the megass con-
tained from 46-82 per cent, to 48-45 per cent, carbon, from 6-30 per cent, to
6-67 per cent, hydrogen, from 44-94 per cent, to 46-43 per cent, oxygen, and
from -14 per cent, to *18 per cent, nitrogen.

3. It was supposed that the fibre from the softer varieties of cane might
contain more pentosans and xylan than that derived from the harder varieties,
but the differences found were quite insignificant.

4. Differences in the cellulose content of the fibre were insufficient to
account for the observed variation in fuel value, although as a general rule a
cane rich in cellulose affords a satisfactory megass as fuel.

5. Differences in the silica content of the samples examined were trifling,
and insufficient to account for the variations observed in practice ; it was
thought that perhaps a large quantity of easily fusible ash might coat the
megass and prevent its combustion, or might choke the air inlets between the
fire bars.

6. Great variation was observed in the volume occupied by the same
weights of the megass from different varieties ; the weight of 100 c c. of
megass varied from 5-45 grms. to 7*95 grms., and the following observations
were drawn : —

a. The denser megasses were of superior fuel value.

I. The denser megasses are generally rich in cellulose.

c. Canes containing most fibre also give a megass of superior fuel

value.

Looked at in the light of these determinations, the question of the fuel
value of a megass is reduced to one of the mechanical structure of the fibre ;
a megass of low apparent specific gravity will thus occupy a large volume per
unit of weight ; the volume of megass which can be held on the grate of a
furnace is limited, and with the megass of low density it may happen that the
supply of fuel fed to the furnace is not sufficient to maintain steam for the
factory's needs ; when a different type of megass is being fired, owing to its
greater apparent specific gravity a greater weight is contained on the grate
without any change in volume, and steam is kept up without difficulty.

412

MEGASS AS FUEL.

This matter is one of great importance in furnace design, as a ratio of
grate area to heating surface which gives excellent results with the megass
from one variety of cane may be quite insufficient when the megass from
another variety is being stoked, although the total heat units available per ton
of cane may be identical in both instances.

It must, however, not be overlooked that the quantity of fuel varies with
the percentage of fibre in the cane, and that this cause will often explain a
shortage of fuel ; the results summarized immediately above tend to explain
the state of an abundance of fuel and insufficiency of steam which most people
connected with a sugar factory must have experienced.

Effect of Moisture on Thermal Value.— The difference in the
thermal value of the same megass when the moisture varies from 48 per cent,
to 52 per cent, is not very great, but Bolk6 has shown that at about the higher
limit the temperature of combustion is so lowered that decomposition
products distil over incompletely burnt, and with this incomplete combustion
very great heat losses occur.

Heat Available from Megass.— This calculation can best be
shown by worked out examples.

Let the megass burnt contain 45 per cent, water and 55 per cent, dry
matter ; let the flue gases leave the boiler at a temperature of 550° F., the
temperature of the atmosphere being 84° F. ; let the air entering the furnace
be twice the theoretical amount necessary for combustion ; let the megass
contain 46-5 per cent, carbon, and 6 -5 per cent, hydrogen, calculated on dry
weight, or 25 '6 per cent, and 3'6 per cent, respectively, on actual weight.

To raise 1 Ib. of water from 84° F. to 212° F. requires 128 B.T.TJ. ; to
convert this water into steam at 212° F. requires 966 B.T.U., and to heat this
steam at constant pressure to 550° F. requires (550 — 212) -48 = 162 B.T TL,
the specific heat of steam at constant pressure being '48.

Each pound of water vapour in the flue gases then carries away
128 4- 966 4- 162 = 1256 B.T.TJ. The specific heats of carbon dioxide^ oxygen
and nitrogen are '22, -22, and -24, respectively, so that each pound of carbon
dioxide in the flue gases will carry away '22 (550 — 84) B.T.U., and similarly
for the oxygen and nitrogen.

On combustion each pound of carbon gives 3*67 Ibs. of carbon dioxide,
and each pound of hydrogen 9 Ibs. of water.

Per pound of megass the products of combustion are then

Carbon dioxide -256 X 3'67 = '939 Ibs.

Oxygen in excess air .. .. -256x2-67= '683 ,,

Nitrogen -256 X 2 X 9-36 = 4-792 ,,

Associated water '45 ,,

Combined water -036 X 9 = -324 ,,

413

CANE SUGAR.

The heat carried away in the flue gases is then

Carbon dioxide .. <. .. '939 X '22 (550 — 84) = 96 B.T.U.
Oxygen in excess air . . . . -683 X '22 (550 — 84) = 71 ,,

Nitrogen 4*792 X '24 (550 — 84) =536 „

Associated water .. ., ^. .. '45 Xl256 = 565 ,,
Combined water \. .. '324x1256= 407 ,,

Total .. 1675

The total heat generated by the megass on combustion is, following on
a previous paragraph, 8350X'55 = 4582B.T.U. So that in this case the
percentage loss in flue gases is 36-6 per cent., leaving 63'4 per cent., or 2905
B.T.U. available for making steam.

As an extreme instance of economical working let the flue gases (due to
the use, say, of a fuel economizer) leave at 350° F., and let the excess of air
be 50 per cent. Then the heat earned away in flue gases calculated on
similar lines as in the case above is

Carbon dioxide '939 X '22 (350 — 84) = 55 B.T.U.

Oxygen in excess air . . . . -341 X '22 (350 — 84) = 40 ,,
Nitrogen .. .... .. 3*694 X '24 (350 — 84) = 236 ,,

Associated water -45 X 1160 =522

Combined water . -324 X 1160= 375

Total 1228

In this case, then, the total loss in flue gases is 26*9 per cent, of the heat
value of the megass, and 3349 B.T.U. are left available for raising steam.

In addition, however, there are the losses in unburnt fuel, in hot ashes,
and in radiation, the exact magnitude of which it is impossible to estimate.
Probably these losses account for 5 per cent, to 10 per cent, of the total value
of the megass ; estimating them at the latter figure, in the first instance
2440 B.T.U., and in the latter case 2891 B.T.U. will form steam. The
evaporation of one Ib. of water from and at 212° F. requires 966 B.T.U., so
that referred to this temperature and pressure, 2-55 Ibs. of steam in the one
case, and 2 '99 Ibs. in the second would be obtained.

As compared with coal firing the very great losses due to the associated
and combined water met with in the combustion of megass and other low
grade fuels should be noticed.

Consumption of Steam in Proportion to Available
Fuel. — In " Sugar and the Sugar Cane" the writer was at pains to calculate
the heat required to treat the juice obtained from various types of canes,
containing different amounts of sugar and fibre, both wet and dry crushed, and
also crushed with the addition of maceration water, in order to see how far the
megass would serve as fuel. The heat value of the megass was calculated

414

MEGASS AS FUEL.

from its analysis, and since it is now known that heat values thus obtained are
lower than those obtained by the use of the calorimeter, the calculations are to
a great extent invalidated. Further, the writer has come to the conclusion
that conditions in different districts are so widely variant that it is useless to
select typical instances, and that the subject can only be treated on broad
grounds, leaving it to those interested to adapt the general principles involved
to their own special cases.

Effect of Fibre. — Properly speaking, the fibre alone should be
considered as a fuel constituent of the cane, as the sugar is too valuable a
constituent to burn ; accordingly, the fuel produced by the cane will be in
direct proportion to the amount of fibre ; furthermore, where the canes are
crushed without the addition of water, not only is the amount of fuel increased „
but the quantity of juice to be treated is proportionately lowered. For
example, let in one instance the canes contain 10 per cent, fibre, and in a
second 14 per cent, fibre; let the megass contain 45 per cent, fibre; then
in the first instance per 100 tons of cane 77-78 tons of juice and 22-22 tons of
megass result; in the second instance, 68*89 tons of juice and 31*11 tons
of megass. These differences are so large that one factory burning large
quantities of extra fuel may be really working more economically, in so far as
regards the production of steam, than one which has a surplus.

Effect of the Solid Content of the Juice on Steam
required. — Let canes containing the same amount of fibre yield in the one
case juice of 15° J3rix, and in a second case juice of 20°Brix. Let the megass
in both instances contain the same amount of fibre ; then with a comparatively
small error the available fuel will be the same. The evaporation of juice of

15° Brix to syrup at 55° Brix indicates the removal of — — -7272 parts

of water per unit of juice ; if the evaporation is done at quadruple effect, the
equivalent evaporation at single effect is -1818. The evaporation of juice at

Q e 1 r

15° Brix to massecuite at 95° Brix indicates the removal of — — — = '8421

95

parts of water per unit of juice ; the evaporation to syrup required the
removal of '7272 water per unit of juice, hence the evaporation at single
effect entails the removal of '1149 parts water per unit of juice; the total
evaporation, then, from juice to massecuite is equivalent to the removal at
single effect of -1818 + '1149 = -2967 parts water per unit of juice.

Similar calculations for a juice at 20° Brix initially give the evaporation
to syrup at 55° Brix as equivalent to the removal of '1591 part water per unit
of juice, and the evaporation of the syrup to massecuite as equivalent to the
removal of '1532 part water per unit of juice, the total evaporation from
juice to massecuite being equivalent to the evaporation at single effect of
•1591 4 -1532 = -3123 part of water per unit of juice.

415

CANE SUGAR.

Actually, then, under factory conditions, a sweet juice demands a greater
•consumption of steam in evaporation than does an equal weight of one of less
sugar content.

Relative Consumption of Steam in Different Stations
in the Factory, and Potentiality of the Megass as Fuel.—

As a basis of calculation canes containing 12 per cent, fibre are assumed to
afford a weight of diluted juice equal to that of the canes ; the megass is
assumed to contain 45 per cent, water and 55 per cent, solid matter, of which
50 per cent, is fibre; hence, 'per 100 (short) tons of cane there are obtained
24 tons of megass, which will afford on combustion 220,880,000 B.T.TJ.,
and if 65 per cent, of this be taken as available for steam, there results
143,572,000 B.T.U. per 100 short tons of megass. The Brix of the diluted
juice is taken as 16°.

Heating Juice to Boiling Point. — Taking the specific heat of the solids
as equal to '301 that of sugar, the specific heat of the juice is *84 + '301 X
-16=r-888. To heat 100 tons juice from 84° P. to 212° F. there are then
required 100 X 2000 X (212- 84) X '888 = 22,732,000 B.T.TJ., or 15*8 per
cent, of the the total available.

Cleaning Juice in Open Pans. — When making consumption sugars it is in
some factories customary to clean the juice in eliminators ; the writer has
observed a concentration of from 1'5° to 2° Brix during this process. If the
evaporation is taken as 10 per cent, of the weight of the juice, there are
evaporated 20,000 Ibs. water ; for the evaporation of 1 Ib. of water from and
.at 212° P. there are required 969-7 B.T.TJ.,* so that the consumption here is
19,390,000, or 13-4 per cent, of the total available.

Evaporation at Triple Effect. — It is supposed that juice is not cleaned in
open pans, and that the syrup is turned out at 55° Brix. The evaporation is

then 55 ~16=r -7091 of the total amount of juice, or 141,820 Ibs. of water
55

from 100 tons of juice. Let each pound of water evaporated require 350
B.T.TJ.; then the consumption is 350 x 141, 820 B.T.TJ. = 49,637,000 B.T.TJ.,
or 34*5 per cent, of the total available.

E>aporation at Quadruple Effect. — Each pound of water evaporated is
assumed to require 290 B.T.TJ.; then the consumption is 290 X 141,820 = 28*9
per cent, of the total available.

Evaporation to Massecuite. — The total amount of water removed in
repeated boilings of syrup and molasses is the same as if the syrup were in one
process concentrated to that pitch which would give refuse molasses, provided
the molasses resulting from the curing of various massecuites are not diluted
previous to reboiling. Let the concentration of the massecuite be 96° Brix.

* This is the value very recently determined by Peabody, and replaces the older value, 966,
found in all earlier tables.

416

PLATE XX,

FIG. 225.

MEGASS AS FUEL.

The total evaporation from 16° Brix is then — — — = -8333 ; in the evapora-

9o

tion to syrup '7091 of the weight of the juice was removed, so that at simple
effect in the pan -1242 is removed, or 24,840 Ibs. water per 100 tons of cane.
At the prevailing vacuum in the pans each pound of water will require about
1070 B.T.CJ., so that the consumption of heat is 26,578,000 B.T.TL, or 18-5
per cent, of the total available.

The above calculations are, the writer thinks, as far as the data available
allow one to go. Experimental data are so absent that the consumption of
heat in the motors, in losses in steam piping, in losses in the cooling of juices
and syrups cannot be even approximated. It is of course in the heating and
evaporation that the consumption of heat is greatest. Putting on one side
cylinder condensation, but very little heat is used in the motors, and the great
part of the heat of the steam entering the cylinders of the engine is available
for evaporation.

In the calculations above with quadruple evaporation the total expenditure
in heating and in evaporation of juices and syrups sums up to 63'2 per cent, of
the total available, leaving a very large margin for use in other stations, on
which definite values cannot be put.

It may then be stated that under ordinary conditions a sugar factory can
be worked with a heavy maceration on the fuel provided by the megass, and
that it is only under exceptional conditions (low fibre in cane, inefficient
furnace and boiler settings, waste due to losses in steam piping, cleaning of
juices in eliminators) that extra fuel is required.

Losses in Steam Pipes. — The following table gives the hourly loss
in B.T.TJ. from naked wrought-iron pipes ; this table is adapted from one
given by Hausbrand and expressed in Centigrade metric units : —

Excess Loss in B.T U. Excess Loss in B.T.U. Excess Loss in B.T.U.

Temperature, per sq. ft. per Temperature. per sq. ft. per Temperature. per sq. ft. per

F.°
40

hour.
80

F.°
140

hour.
370

F.«

240

hour.
749

60

.131

160

436

260

832

80

185

180

509

280

925

100

239

200

580

300

1015

120

304

220

663

320

1120

The effect of lagging is shown in the following data, due to the same
authority : —

A steam pipe at 275° F. and external air at 59° F. condensed per square

foot per hour —

Ibs. steam.
Naked -615

Lagged with silk waste 1 in. thick '091

,, ,, cork shavings 2-2 in. thick . -095

,, ,, kisselguhr -131 - -183

i.e. the losses can be reduced about 80 per cent.

417

27

CANE SUGAR.

In a sugar factory the main steam pipes will be at a temperature of say
324° F., and the back pressure pipes at a temperature of say 224° F. ; the
average of these is 274° F, and assuming an equal area in main and back
pressure piping it will be sufficient then to take the steam piping as having an
excess temperature over the air of 200° F. From the table above then each
square foot of unprotected piping will lose 580 B.T.U. per hour, and per 1000
square feet the loss is 580,000 B.T.TL If each pound of megass gives for use
in the factory 2922 B.T.U., the loss per hour per 1000 square feet is very nearly
2000 Ibs. ; if 80 per cent, of this loss be economized by lagging, the loss per
hour per 1000 square feet of pipe area is reduced to 400 Ibs. amounting in a
day of 24 hours to 9600 Ibs. of megass. This rough and imperfect calculation
is introduced to show the magnitude of heat losses in steam pipes and the
differences which may be found between compact and straggling factories and
between careful and careless equipment.

Heat Value of Megass as influenced by the 'Extrac-
tion.'— The samples of megass, the heat value of which was determined by
Geerligs, contained but little sugar, and were representative of well exhausted
megass ; the thermal value of sugar is lower than that of the cellulose and
xylan, so that with less well crushed megass the thermal value per pound of
dry matter will tend to decrease, but only to a relatively small extent.
Megass approximating to 46-5 per cent, carbon gave a thermal value approx-
imating to 8350 B.T.U. per lb., or 17,978 B.T.U. per Ib. of carbon. It might
be sufficient to use this value in calculating the thermal value of a megass
from its analysis which should include determinations of the cellulose, xylan,
sugar and glucose.

Incidentally it may be remarked that these determinations of Geerligs
and others show how incorrect is the use of ' Welter's ' rule which states that
the heat of combustion of an organic compound is the heat of combustion of
its elements, after deducting the hydrogen which will go to form water ; with
the carbohydrates this would imply that their heat of combustion is the same
as that of the carbon they contain. The heat of combustion of carbon is
14,400 B.T.U., so that a megass containing 46!5 per cent, carbon would only
afford -465 x 14,400 = 6696 B.T.U. as compared with the 8350 B.T.U.
found on actual experiment.

Use of the Waste Gases to dry Megass. — In Mauritius many
factories have erected apparatuses known as secheries for the purpose of the
utilization of a part of the waste heat of the flue gases. A secherie, Fig. %24,
consists of a large stone or brick chamber into which the flue gases are
exhausted by means of fans ; it is usually about 40 ft. long with an internal
breadth of six or seven feet, and about 30 ft. high. The green megass is
delivered into the sechene by the carrier a falling on to the upper endless belt I ;
three such belts are usually provided ; from the lowest the megass falls on to

418

H PI

MEGASS AS FUEL.

the carrier <? which conveys it to the furnaces. The carriers are formed entirely
of metal and are driven at a speed of from six to eight feet per minute, the
megass remaining in the secherie from 15 to 20 minutes ; the flue gases enter
at d and leave through the smoke stacks at/; at g are shown doors for cleaning
up the megass which falls to the ground, and at e a door gives access to the
interior in case of accidents. Three engines are required, one to drive the fan,
one to drive the carriers in the secherie, and one for the cross-carrier from the
secherie to the furnaces. On an average as many as 15 to 20 labourers are
required, chiefly for the purpose of sweeping up and carrying to the furnaces
the megass which falls down. The megass in the secherie is liable to ignite,
and will invariably do so if the temperature of the waste gases exceeds 550°F.
There is a very considerable and undeterminable mechanical loss due to the
finer light and dry particles of megass being carried away ; and finally the
megass in the furnaces is so fine that it falls through the furnace bars, and is
liable to be swept through the flues unburnt.

Another design to
the same end is shown
in the Huillard7 Drier in
Fig. 225 (PLATE XX.),
The economy of these
devices can be shown
by the following cal-
culations.

In Mauritius the
writer found that megass
entering a secherie with
50 per cent, of moisture
would leave containing
only 35 per cent. ; this
amount of water corresponds very closely with the evaporation of half the
original moisture. In a calculation of heat lost in flue gases in a previous
paragraph 565 B.T.U. per Ib. of megass were found to be carried away in the
associated water ; a saving of half of this would be 282 B.T.U., reducing the
heat carried away in flue gases to 1393 B.T.U., and expressed as a percentage
on the total heat of megass the loss in flue gases will now be 30 A per cent,
as compared with 36-6 per cent, as previously calculated.

Value of Megass as compared with other Fuels.— The

relative value of megass, wood and coal is often required, as fuel statistics are
generally based on the coal value of the fuel burnt. There is no constant fuel
value for either megass or coal, and any factor adopted depends on the local
conditions ; coal, depending on its quality and the skill used in firing, may
give from 7 to 12 Ibs. of steam per Ib. consumed. On an average from 4 to 5

Q

Q

Q

FIG. 224.

419

CANE SUGAE.

tons of megass are equal to a ton of average coal. Woods, weight for weight
and of the same water content, have practically identical values ; air-dried
wood usually contains from 20 per cent, to 30 per cent, of water and from 3
to 3*5 tons are equal to a ton of average coal. Molasses are of very similar
value to wood, the predominant factor heing, of course, the water content.
€ane straw contains as a rule ahout 10 per cent, moisture and from 2'5 to 3
tons are equal to a ton of coal. A table giving a comparison of fuel values

follows : —

Gross B.T.U.
Fuel. per Ib.

Welsh Steam 15,000—16,000

Pennsylvania Anthracite .. n .. 15,000—16,000

Newcastle 14,000—14,500

Lancashire 14,000—14,500

Scotch 13,000—14,000

Australian 13,000—14,000

Indian 13,000—14,000

Patent Fuel 15,000—16,000

Air-dried wood 25 per cent, moisture . . . . 4,500—5,000

Green Megass 45 per cent, water 4,500

Cane Straw 10 per cent, water 7,500

Molasses 25 per cent, water 4,500

Petroleum 16,000—17,000

Carbon 14,400

Fuel Value of Molasses.— Molasses are occasionally used as fuel
in sugar factories. Calculated from its analysis a molasses of composition —
sugar, 35 per cent., glucose, 25 per cent., organic non-sugar, 13 per cent,
water, 20 per cent., ash, 7 per cent., will afford on combustion about 4500
B.T.U. per Ib. ; actual determinations by Atwater8 have given a value of 6956
B.T.U. per Ib. of dry matter. The simplest, and a very efficient, way to burn
molasses is to let it fall on to the megass on its way to the furnaces. In
other cases the molasses are ' atomised,' and burnt in a special furnace, or, in
conjunction with the megass, in the furnaces initially designed for their com-
bustion.

Fuel Value of Cane Straw.9— Determinations of the fuel value of
cane straw by Hoogewerf gave per Ib. of dry matter 7841 B.T.U. per Ib. ;
Kooning and Bienfait found a value of 7407 B.T.U. per Ib.

Control of the Fuel Consumption.— A factory working up 1000
tons of cane per day burns more or less 240 tons of megass ; this megass is equal
in value to about 60 tons of coal, and at the furnace mouth is then worth not less
than £120 ; if all this fuel were bought it is inconceivable that a most careful
•control would not be kept ; even if no extra fuel is burnt economy in fuel may
mean a higher dilution and better extraction, and in many cases any extra
megass may be used in a distillery, as fuel for pumps, and in the future
possibly as a source of paper. A fuel control may be obtained as indicated
very briefly below.

420

MEGASS AS FUEL.

FIG. 226.
hours' duration can be obtained.

Analysis of the Flue Gases.-— With perfect combustion, ie.,
with no excess of air. the fuel gases should contain 20 per cent, of carbon
dioxide ; in actual practice 1 5 per cent, is a very high figure and an average

of 10 per cent, cannot be con-
sidered unreasonable. The best
method for obtaining intermittent
analyses of the flue gases is
described below.

Collection of the Sample. —
Specially designed bellows may
be obtained from dealers, but the
writer prefers to use the aspirator
shown in Fig. 226 ; by adopting
means for regulating the flow
of water, a sample over several
The water in bottle a next to the flue is
covered with a layer of oil. Before collecting the sample of gas the tube
let into the flue should be well rinsed with the flue gases by means ot*
alternately lowering and raising the bottle b.

For the analysis of the flue
gases the following solutions are
required : —

1. Caustic soda of density 60°
Brix. For carbon dioxide.

2. Twenty -five grms. pyrogallol
dissolved in 50 c.c. hot water and
mixed with 100 c.c. caustic soda of
density 50° Brix. For oxygen.

3. Cuprous chloride in hydro-
chloric acid. Dissolve 35 grms.
cupric chloride in 200 c.c. hydro-
chloric acid of specific gravity 1'20 ;
add a quantity of copper turnings,
and preserve in a stoppered bottle
for 48 hours with occasional shaking ;
then add 120 c.c. of water. For
carbon monoxide.

The apparatus (Orsat-Lunge)
shown in Fig. 227 is the most con-
venient form for analysis. The bulb b is filled with caustic soda up to the
mark on the neck, the bulbs c and d being filled in the same way with the
pyrogallol and cuprous chloride solutions. The filling is performed by first

Fie. 227.

421

CANE SUGAR.

disconnecting the bulb and filling half way up by pouring in the solution ;
the bulb is then placed in position, the cock g opened, the bottle lowered,
when the solution in the bulb rises and may be adjusted to the mark.

The burette a is to contain the measured volume of gas ; it is first of all
filled with water by raising the bottle i, the three-way cock h being open to
the atmosphere and the cocks on the bulbs closed. The bottle containing the
sample of gas is then connected with the tube <?, the bottle i lowered, and
the cock g opened to the sample bottle, the bottle I is then raised and
the gas in a is forced into the burette ; a little more than 100 c.c. is forced
in, and then by raising the bottle i and opening the cock g to the atmosphere,
exactly 100 c.c. of gas may be obtained in the burette a, the water level in a
and i being the same. The cock g is then closed ; the bottle i is raised, and
the cock on b being opened, the gas is forced into the bulb b, where it is
allowed to remain a short time ; the cock on b is then opened, and by lowering
the bottle i the unabsorbed gas is drawn back into a, and after adjusting the
water levels in a and * the volume absorbed is read off the scale. The
operation is repeated to make sure that absorption is complete ; the process is
repeated in the other bulbs ; and the nitrogen is estimated by difference.

What is required, however, in a factory, is not an occasional record,
obtained at the expense of much time and personal inconvenience, but a con-
tinuous record. Of the devices purchasable to this end the writer thinks the
1 Simance-Abady' C02 Recorder the most perfect; this instrument gives with
accuracy a continuous record of the per cent. C02 in the flue gases. Such a
record affords the superintendent a complete control over the combustion.

Calculation of Excess of Air from Analysis of Flue
Oases. — In air the nitrogen present occupies a volume of 3 '74 times that of
the oxygen. Hence if x be the percentage of oxygen, and y be the percentage
of nitrogen found in flue gases on analysis, this equation results :
Total quantity of air used __ y

Theoretical quantity ~~ y — 3 • 7 4#
If on analysis y is found to be 79% and x, 8'0, the excess of air is

79-2
79-2- 29-9 = 1>598»

or 59*8 per cent, more than the theoretical minimum of air is used.

Control from Temperature Observations.— From the com-
position of a megass and from determinations of its thermal value it is possible
to calculate the temperature of the products of combustion ; thus a pound of
megass, which on combustion with the minimum amount of air gives -939 Ib.
carbon dioxide, 2'39i Ibs. nitrogen and "771 Ib. water vapour, and which is of
thermal value 4592 B.T.U., will have a combustion temperature over and
above that of the surrounding atmosphere of

4592 =8988°F.,

•939 X '22 -{- 2-394 X '24 + -7 7 1 X '48
422

MEGASS AS FUEL.

the specific heats of carbon dioxide, nitrogen, and water vapour being '22, *24,
and '48 respectively. If twice the quantity of air necessary for combustion
was used, the combustion temperature will be

•939 x -22 + 4-788 X '24 + '683 X '22 + '771 X '48
since there are now 4-788 Ibs. nitrogen and -683 Ib. oxygen in the flue gases.

The more air admitted to the furnaces the lower is the temperature, and
hence observations of the temperature of the furnace give a means of overseeing
the carefulness of the firing.

If the temperatures in the furnace, i.e., the combustion temperature, and
the temperatures of the waste gases be known, then the efficiency of the
furnace can be at once obtained from the expression,

j< _ ^
Efficiency == - ,

where T and t are the excess temperatures of combustion and of the waste
gases over and above the temperature of the outside air ; thus, if the com-
bustion temperature be 1884° P., the waste gas temperature be 584° P., and
that of the outside air be 84° F., then the efficiency is

1800-500

1800

perfect work being represented by unity. This calculation does not allow for
heat losses due to radiation and to unburnt fuel, or to air leaks between the
combustion chamber and the fuel, but will give strictly comparative results from
day to day. The immediately preceding sections show how from the flue gas
analysis and the megass analysis, first the excess air and then the combustion
temperature can be calculated. What is required, however, in actual work is
a continuous automatic record to which the mill superintendent can refer at
his leisure, and immediately below attention is called to the very beautiful
instruments which have been devised in the last decade for the accurate
determination of high temperatures, and which are now to be obtained from
dealers,

1. Electric Resistance Pyrometers. — The resistance of a conductor to the
passage of an electric current is a function of the temperature prevailing in
the conductor ; this relation has been very carefully worked out for a number
of conductors, and especially so in the case of platinum ; hence if a current of
fixed voltage or E.M.F. flow through a platinum wire, observations of the
current produced give means of obtaining the resistance of the conductor by
means of Ohm's law, current X resistance = voltage, whence from previously
ascertained experimental observations the temperature of the conductor and
(in the special instance considered) of the gases in the combustion chamber of
the furnace are obtained. These instruments are constructed so that readings
are obtained aurally by means of a telephone attachment, or visually by means
of the deflection of a galvanometer needle.

423

CANE SUGAR.

2. Thermo- Electric Pyrometers. — If wires of two dissimilar metals be in
contact at their ends, and if the temperature of the two ends be different, an
electric current flows along the wire, and its voltage or E.M.F. is a function
of the temperature difference between the heated and cold ends : this arrange-
ment is called a thermo-electric couple, and by simply measuring the E.M.F.
thus obtained, the temperature at the hot end follows. For high temperature
work the thermo couple is made of platinum and rhodium, and will indicate
correctly temperatures up to 2900° F.

3. Radiation Pyrometers. — In this instrument the rays of radiant heat
emitted from a hot body are brought to a focus by a suitable combination of
lenses and arc directed upon the junction of a thermo-electric couple. From the
E.M.F. or voltage the temperature is directly obtained.

4. Optical Pyrometers. — The optical pyrometer of Wanner is based on the
colour produced by incandescent bodies : its theory is rather complicated.
Externally the instrument closely resembles a polariscope, and it is used in a
very similar way, being directed towards the body whose temperature is being
determined : the critical appearance of the field of vision thus observed and
the means of obtaining it are very similar to those used in polarimetry.

Of these instruments the first three can be provided with a continuous
recording device. The electric pyrometers are perhaps not suitable for the
very high temperatures of the combustion chamber ; this is chiefly due to the
difficulty in protecting the platinum wire or the couple from the action of the
furnace gases. The combination arranged by the Cambridge (England)
Scientific Instrument Co. recommends a Fery radiation pyrometer for deter-
mining the temperature of combustion, and a thermo-electric couple for the
flue gas and feed- water temperatures. A complete outfit costs less than £100,
and in a factory of any size should quickly pay for itself.

Megass as a paper making Material.— Attention was first
called to this possibility in Guadeloupe in 1872, and it has been frequently
suggested during the last few years. Amongst the large amount of irresponsible
matter that has been written the following definite statements have appeared : —

It has been stated that megass owing to its length of fibre yields a very
good half stuff wrapping paper, there being a yield of 48 per cent, of half
stuff from megass. The failure of experiments in Java is stated to be due to
local conditions and not to the quality of the raw material. Thiele11 has given
a description of the results obtained with diffusion megass in a factory in
Texas; the crude material contained 82 per cent, water, 16*5 per cent, crude
cellulose, '75 per cent, carbohydrates and '75 per cent, ash of which 82*77
per cent, was silica ; the megass was allowed to ferment in heaps with frequent
watering whereby the pectins were destroyed; a charge of 40,0001bs. of
fermented megass was boiled in a * rotary ' for four hours under a steam

424

MEGASS AS FUEL.

pressure of 90 Ibs. per square inch with 450 Ibs. dry soda and 250 Ibs. quick-
lime. After washing the material was ready to go to the paper machine.

The resulting paper is very strong and suitable for wrapping purposes ;
from 40,000,000 Ibs. of chips 8,000,000 Ibs.* paper were obtained, which sold
at 2 cents, per Ib. or £9'3 per ton. More recently paper making from
megass, para grass (Paspalum sp.) bamboo, etc., has been initiated at the
Tacarigua estate in Trinidad by Laraarre12 where a material worth £5 per ton
is stated to be produced.

A very recent examination of megass by Remington, Bowack, and
Carrington13 gives the following analysis of megass fibre: Water, 11*05 per
cent.; ash, 1*54 per cent.; loss on ^-hydrolysis, 30'01 per cent.; loss on
i-hydrolysis, 48*70 per cent. ; loss on mercerization, 32-73 per cent. ; gain on
nitration, 10-21 per cent.; cellulose 47'11 per cent.; length of ultimate fibre,
3'5 mm. These authors speak very favourably of the possibilities of megass
as a raw material for paper making, especially when mixed with other
substances such as chemical wood pulp, lalang (Andropogon caricosm] and
Para grass.

Finally, Raitt14 comes to the following conclusion, based on very con-
servative figures : —

" Cane sugar factories are usually situated in localities where all manu-
factured goods have to be imported at a considerable cost for freight, and,
probably, import duties also. Where such circumstances exist, together with
a sufficient local demand for unbleached wrapping and packing papers, or even
for the thin, unbleached paper so largely used by the natives of India and
elsewhere for correspondence and accounts, it is quite possible tq show that a
paper mill may prove a very profitable auxiliary to a sugar factory, and that
the megass may be worth considerably more for this purpose than its present
fuel value.

A paper mill suitable for this class of paper, to produce 40 to 50 tons per
week, would cost, roughly, £20,000. A conservative estimate of the cost of
production, under average conditions, exclusive of the fuel value of the megass
but including repairs, depreciation, and 5 per cent, interest on cost of plant,
amounts to £10 10s. per ton. Under the conditions above referred to the
product should be worth £15, leaving £4 10s. as the paper-making value of
the 2£ tons of megass required to produce it, or, say, £2 per ton. The
cost of steam coal to replace it in the sugar factory furnaces would be
at the outside £l 10s. per ton. In calorific effect a ton of good steam
coal is usually assumed to be equal to four tons of megass, so that the
full value of the latter cannot exceed 7s. 6d. per ton. Deducting this,
there remains an estimated profit of £1 12s. 6d. per ton of megass converted
into paper."

* i.e., 20 per cent.; but the megass only contained 16'5 per cent, cellulose originally ; the
figures are correctly quoted.

425

CANE SUGAR.

REFERENCES IN CHAPTER XX.

1. Proc. Inst. Mech. Eng., December, 1902.

2. Proc. Inst. Civ. Eng., 123, 370.

3. Jour, fur Pract. Chem. (2), £5, 305.

4. Arch., 1906, 445.

5. La. P., 1896, 11.

6. Arch., 1906, 319.

7. /. 8. J., 103.

8. La. P., 1896, 11.

9. Bull. Assoc. A~bs., May, 1905.

10. Papier Zeitung., 28, 2891, abs. in Jour. Soc. Chem. Ind.

11. Chem. Zeitung., 25, 289, abs. in Jour. Soc. Chem. Ind., 20, 495.

12. /. 8. J., 114.

13. World's Paper Trade Revieiv, October, 1909.

14. Tropical Agriculturist, January, 1910.

426

CHAPTER XXI.

THE POLARISCOPE AS APPLIED TO SUGAR ANALYSIS.

Ordinary light is the effect on the eye of vibrations of the ether, these vibra-
tions taking place in all directions ; by certain optical devices these vibrations
may be confined to one plane, and such light is called polarized light. If such
light pass through a layer of certain bodies, e.g., quartz, cane sugar and many
others, the plane in which the vibrations occur is rotated ; these bodies are
termed ' optically active,' and instruments devised for measuring the rotation
of the plane of polarization are called polariscopes or polarimeters, and when
specially applied to sugar analysis, saccharimeters*

Laws governing the Rotation of the Plane of Polariza-
tion.— 1. The angle through which the plane of polarization is rotated is
directly proportional to the thickness of the layer of active material through
which the light passes.

2. When the active body is in solution the angle through which the plane
of polarization is rotated is directly proportional to the concentration of the
solution, i.e., to the amount of active material present.

3. The angle through which the plane of polarization is rotated is depen-
dent on the temperature, the nature of the light, the nature of the solvent,
and is affected by the presence of other bodies themselves inactive.

The law given in 2 above is only approximately true ; in most cases it is
true within the limits of the errors of technical assay. The first three disturb-
ing factors mentioned in 3 are readily capable of control by always working
under similar conditions ; the last disturbing cause is not so amenable to control ;
fortunately in sugar analyses it is not a predominant source of error.

From the above it follows that, if the angle through which the plane of
polarization is rotated be measured for any one concentration of a sugar
solution, and if the length of the column of sugar solution through which the
polarized light passes be known, then with a solution of sugar of unknown con-
centration the measurement of the angle through which the plane of
polarization is rotated gives a means of calculating the concentration of the
solution of unknown strength.

* It is usually stated that the asymmetry of a carbon atom in the molecule of an organic
body determines its optical activity ; actually the asymmetry of a nitrogen, silicon or sulphur, or
tin atom is equally sufficient ; further Perkin, Pope and Wallach have at this present time
(Dec., 1909) prepared an optically active body the activity of which is due to enantiomorphism
of molecular configuration.

427

CANE SUGAR.

Specific Rotatory Power is the rotation at 20° C., expressed in angular
degrees, of plane polarized light corresponding in wave length to that of the
yellow D line of the solar spectrum, when the light passes through a column
of a solution of the active material 10 cm. long, containing one grm. of active
material in one c.c.

Kind of Light employed. — For scientific purposes it is necessary
to refer all measurements to one source of light, and the light obtained from
an incandescent sodium salt corresponding to the D line of the solar spectrum
has been adopted. For technical sugar analysis polariscopes are adapted (in
nearly all cases) to use ordinary white light. In what follows in explaining
the use of polariscopes as apart from saccharimeters, it is assumed that the
source of light is homogeneous and monochromatic.

For the theory of this source of light reference should be made to
Landholt's classical treatise.

FIG. 228.

The Nicol Prism and Means of obtaining Polarized
Light. — Polarized light is obtained for use in the polariscope by means of a
nicol prism or some development of it. If ordinary light pass through
crystals of certain bodies, of which Iceland spar is an example, it suffers
double refraction, and is split up into two rays, one of which is known as the
ordinary and the other as the extraordinary ray. A nicol prism is formed out
of a prism of Iceland spar, the ends of which make angles of 71° and 109° ;
the ends of the crystal are ground until they form angles of 68° and 112°;
the crystal is then split diagonally, and at right angles to the plane of the
ends and to the principal axis, i.e., along a c, Fig. 228 ; the surfaces are then
polished and united with a film of Canada balsam.

Let ee represent a ray of light entering the prism ; this ray is doubly
refracted into two rays, one taking the direction e p, and the other the
direction e h. e p is the ordinary, and e h the extraordinary ray ; the ray e p
on meeting the film of Canada balsam a c is reflected in the direction p g,
and provided that the ends of the prism have been ground down to angles of
68° and 1 12°, will pass out of the prism before reaching the surface a d, and is
totally lost if the sides of the prism are blackened. The extraordinary ray i&
less refracted, and emerges from the prism in the direction kk, and is now
plane polarized light.

428

FIG. 229.

THE POLARISCOPE AS APPLIED TO SUGAR ANALYSIS.

The original form of the nicol prism has been modified by several
physicists ; the form used in the most modern instruments is that due to
Glan, which is made as follows : — A symmetrical
rhombohedral crystal, Fig. 229, is selected, and the
two faces are ground down parallel to each other
and perpendicular to the optical axis of the crystal ; at
right angles to these surfaces the prism a b c d is cut
out, and split along the direction b d ; the faces of the
prism and the surfaces at bd are then polished and
the two parts cemented together along the surface b d.
In this prism the field of vision is perpendicular to
and symmetrical with the optical longitudinal axis of the prism, and reflection
from the inclined surfaces as occurs in the ordinary form of nicol prism is
eliminated.

Original Form Of Polariscope. — Let there be two nicol prisms
arranged with their two optical axes in one and the same straight line, and let
a ray of light pass in the direction shown in Fig. 230, and as described in the
preceding paragraph through the prism on the left, referred to as the polarizer ;
and thence on to the similar prism on the right, referred to as the analyser.
Dependent on the relative positions of the prisms all, a part, or none of the
light will reach the eye of an observer looking from right to left towards the
source of light ; if the prisms are set so that their principal axes are parallel
a maximum of light passes ; if set so that their principal axes are not at right
angles to each other, none of the light passes. This position is referred to as
crossed nicols ; between these two positions a portion of the light passes.

FIG. 230.

Now let the two nicols be crossed, then no light reaches the eye of the
observer ; if, now, an optically active material be interposed between the two
nicols so that the plane in which the polarized light vibrates is rotated, a
portion of the light passes, and to obtain the effect of total darkness the
analyser must be rotated about its longitudinal axis through an angle equal in
magnitude, but opposite in sign to that through which the plane of polariza-
tion has been rotated by the optically active material ; now if to the analysing
prism a pointer be attached, which indicates zero on a scale at the position of
crossed nicols, then the angle through which the prism has to be rotated to
again produce the position of total darkness measures the rotation due to the
optically active material.

The first polariscopes constructed by Biot2 actually obtained their reference
point in this way ; but the position of total darkness is not one which can be
accurately determined, and other devices are described below.

429

CANE SUGAR.

Transition Tint Device. — White light is the effect on the eye of
red, orange, yellow, green, blue, indigo, and violet rays ; these rays are, when
polarized, differently rotated in their passage through active bodies ; if, then,
we have two nicol prisms arranged as in the preceding paragraph, with their
longitudinal axes parallel, and rotate, as by the interposition between the two
nicols of an optically active material, any one of these components of white
light through 90°, that component will be eliminated, and will not reach the
eye of the observer ; if the yellow rays are thus eliminated the rest combine
to form a peculiar pale rose or lilac tint termed the transition tint ; the
yellow rays are rotated 90° by a plate of active quartz 3- 75 mm. thick.

This device, originated by Ilobiquet, and constructed by Soleil, consists,
then, in the interposition between the analyser and polarizer of a plate of
quartz 3 '75 mm. thick, one half of which is of dextro- and the other of levo-
rotatory quartz ; then if the nicols are parallel the field of vision (using
ordinary white light) is a uniform pale rose tint, and the pointer attached to
the analyser should indicate zero. Now, if the analyser be rotated but a
little, or if the plane of polarization be rotated by the interposition of an active
material, the proportion of red, orange, &c., rays in the two halves of the field
that reach the eye of the observer is different, on the one side red on the other
side blue rays predominating. This contrast between red and blue is very
pronounced, and measurement of a rotation is obtained as described before by
rotation of the analyser through an angle equal in magnitude, but opposite in
sign to that due to the material whose activity is being measured.

This instrument then obtains its reference point by the elimination of the
yellow ray of white light, and measures the rotation of this ray. Specific
rotations obtained with this instrument are referred to as [a,-] ; (French jaune =
yellow).

The Half Shadow Devices. — In all these instruments the
reference point is a uniformly tinted field ; on introducing a very small
rotation one half of the field becomes darker in tint than the other, the change
being very sharp. With rotation far removed from that giving the reference
point a field of vision approximately uniformly tinted is also observed, and may
be distinguished from that connected with the reference point by there being
no sharp change on introducing a small rotation of the plane of polarization.

The Jellet-Cornu Half Shadow Device.— This half shadow
arrangement was originally devised by Jellet3 in 1860, and since then has been
elaborated by many physicists. As made by Jellet, between the polarizing and
analysing nicols, and close to the former, was interposed a right prism of Ice-
land spar ; this prism was sawn through lengthwise, the opposite faces ground
down to equal angles, and the two halves cemented together in reversed
positions, so that they made an angle a with each other ; this angle is called
the half shadow angle. The Jellet prism was modified in 1870 by Cornu4

430

THE POLARISCOPE AS APPLIED TO SUGAR ANALYSIS.

thus. An ordinary nicol prism (Fig. 231} is bisected in the direction of a
plane passing through the shorter of the two diagonals ; the sectional faces are
cut down 2£°, and the two halves reunited. In this way is obtained a
double nicol prism with two principal sections at an angle of 5° to each other.
Now in Fig. 232 let a f and e d represent the positions of the planes of
polarization of an analyser and polarizer of ordinary construction, when in the
position of crossed nicols ; that is to say, 0/and e d are at right angles to each
other. Now if a prism as devised by Cornu be substituted for the polarizing
nicol, the plane of polarization will now be represented by the line c o b ; let
the analysing nicol be rotated so that its plane of polarization is a /, perpendi-
cular to o c ; then that half of the field of vision will be in total darkness, but
the other half will be illuminated. Similarly, the right hand half of the field
of view can be made totally dark, and when the plane of polarization of the

analysing nicol is in the position

a /, the whole field is equally

illuminated, and this position

forms the critical position. This

position is one of great delicacy,

and a small change from the

position a f results in unequal
FJG- 23L illumination. If the analyser be

rotated so that it comes to the position d e, both halves of the field are
strongly illuminated, and receive nearly a maximum of light, but on slightly
rotating the analyser there is no sharp change as occurs when the plane of
polarization of the analyser is in the position af.

The Lippich Half Shadow Device.— This device, which is
now used in the best instruments of German make, obtains its half shadows
by the interposition of a small Nicol prism between the polarizer and the
analyser, as shown in Fig. 238. The half nicol is so fixed that its edge, (7,
lies in the axial plane of the apparatus, and divides the field of vision into twa
halves. Let the principal sections of the two prisms make an angle, a, with
each other. Light passing through the large nicol, a, and through the open
part of the field, vibrates vertically to the principal section of that prism. Of
the rays that pass through that half of the field covered
by the half nicol, only those pass that vibrate vertically
to the principal section. A field of vision is thus
obtained made up into two halves in which the planes
of polarization are inclined at a small angle to each
other, and the effect is precisely as described when dealing with the other forms
of half shadow instruments. In this instrument the analysing nicol is not set
parallel to the polarizing nicol, but makes with the polarization direction of the
half nicol a larger angle than it does with that of the large nicol, so as to correct
for the absorption of light which occurs in the passage through the small nicol.

431

CANE SUGAR.

The Laurent Half Shadow Device.6— The Laurent half shadow
polariscope obtains its end point in a manner quite different to the instrument
described above. Between the polarizing and analysing nicol of ordinary con-
struction, and close to the former, is interposed a thin plate of active quartz,
which is cut parallel to the optical axis of the crystal. A beam of light
entering such a plate perpendicular to its surface, is doubly refracted into two
beams, with vibration planes parallel, and perpendicular to the optical axis.
In such a system that ray which vibrates perpendicular to the optical axis has
its speed of vibration increased, and the thickness of the plate of quartz is so
taken that that ray vibrating perpendicular to the optical axis has gained half
a wave length on the wave vibrating parallel to the optical axis at the
moment they emerge from the quartz plate. In Fig. 28Jj. let the circle
represent the diaphragm opening, covered as to one half by the quartz plate,
and let the optical axis of the plate be represented by the line o I ; let o a
represent the amplitude of vibration and the plane of polarization of the light
coming from the polarizing nicol. On meeting the quartz plate this ray is
resolved into two rays, o b and o e, parallel and perpendicular to the optical
axis of the quartz plate ; on emerging from the quartz
plate the ray o e has gained half a wave length on the
ray o 19 and is now represented by the line o d. These
two rays can be compounded into the ray o c, precisely
as if the field of vision was illuminated by the rays o a
and o c, symmetrically arranged with respect to the
optical axis of the quartz plate. The effect of this
is to obtain a field of vision exactly similar to that
described in dealing with the Jellet-Cornu apparatus,
and the remarks made there are applicable. It must

be noted that the half shadow angle with this instrument can be varied, the
larger the angle the greater the intensity of the light, but the less the delicacy
of the apparatus. With this apparatus very dark-coloured materials can be
observed, but with a loss in the fineness of the reading.

Horsin-Deon Polariscope.7 — This instrument is of different con-
struction to any of those previously described. The light passes through a
Jellet prism, and then through a plate of dextro-rotatory quartz rather more than
4 mm. thick ; the effect of this is to produce a blue field on the left and a
pale yellow field on the right. The compensator is a wedge of levo-rotatory
quartz, behind which is placed a disc of levo-rotatory quartz, the effect of
which is to produce a final tint rather darker than the sensitive tint of the
colour polariscope. This field of view of this instrument in positions remote
from the zero position is that one half is colourless, and the other coloured in
all colours of the spectrum. Near the zero position the colourless half becomes
tinted before the other half loses its colour ; at the zero position, the field of
view is a uniform field, similar to that of the half shadow instruments.

432

THE POLARISCOPE AS APPLIED TO SUGAR ANALYSIS.

Wild Polariscope.9 — This pattern, which is seldom met with, obtains
its end point by means of the interposition of a Savart polariscope between
the polarizer and analyser, the former being rotated in making a reading.
When adjustment is nearly obtained a number of horizontal dark bands occupy
the field of vision ; on further rotation of the polarizer those occuping the
centre of the field disappear, leaving a clear, bright, vertical band, defined by
a circular banded part on either side ; in the field of vision are arranged cross
hairs, the end point being taken when the three parts of the field are
symmetrically arranged about these.

Trannin Polariscope. — In this instrument the analyser and
polarizer are fixed, and adjustment is made by varying the length of the
polariscope and concentration of the solution.

Broch Polariscope. — This instrument combines the spectroscope
with the polariscope and obtains its end point by the coincidence of a dark
band in the field of vision with the Praunhofer D line. These last two
instruments find no use in sugar analysis.

The Saccharimeter as distinct from the Polariscope.—

In the above descriptions of devices used in polariscopes it was stated that the
angular rotation was measured by rotating the analyser in an opposite direction
to that due to the active material, the rotation being measured directly in
angular degrees, and that monochromatic spectrally purified light was used.
In polariscopes made specially for sugar analysis ordinary white light is used,
the rotation is measured on a linear scale graduated up to 100°, the 100 point
corresponding to the rotation produced by normal weight of pure sugar dis-
solved in 100 cc., and observed in a tube 20 cm. long; the rotation produced
by the sugar solution is neutralized by the interposition of a plate of active
quartz, the thickness of which can be varied, and which is proportional to the
scale reading, the device being known as a compensator.

Normal Weight. — By this term is meant that weight of pure cane
sugar which, dissolved in 100 cc. of water, and observed in a tube of length
20 cm., gives a reading of 100 on the scale of the polariscope.

There are several normal weights in use. Ventzke, the optician, whose
name is connected with the transition tint polariscope, adopted as a standard
sugar solution, one of density 1-1, at a temperature of 17'5°C. ; such a solution
contains 26-048 grms. of sugar in 100 Mohr's c.c., and this weight of sugar
became a very generally accepted normal weight. Mohr's c.c., i.e., the volume
occupied by a grm. of water at 17'5°C., is deservedly falling into desuetude,
and since 26-015 grms. per 100 true c.c. are equivalent to 26-048 grms. per
100 Mohr's c.c., a normal weight of 26 grins, per 100 true c.c. has been
strongly recommended for adoption.

433

28

CANE SUGAE.

The second normal weight, used in instruments of the Laurent pattern,
and in the old Duboscq instruments, is based on the angle through which the
plane of polarization of the D ray of sodium light is rotated by a plate of
quartz 1 mm. thick, cut at right angles to its optical axis ;
this angle, when the sodium light obtained by vaporizing
sodium chloride in a bun sen burner is filtered through potassium
bichromate, is 21-667°, and this is the rotation produced by a
solution of 16-29 grms. of sugar in 100 true c.c., whence this
weight of sugar was adopted as a standard normal weight. This
normal weight has been much confused ; the early Duboscq
instrument used 16-35 grms. as a normal weight ; other instru-
ments were standardized for a normal weight of 16- 19 grms.
The confusion has in part arisen by determinations of the optical activity of
quartz under conditions other than those originally stipulated ; actually, the
rotation of quartz is immaterial, so long as it is known for what normal weight
and for which cubic centimetre the instrument has been constructed.

The Compensator.— The compensating arrangement consists of a
device whereby a variable thickness of active quartz may be interposed and a
rotation equal in magnitude and opposite in sign to that due to the active
material introduced, so that the reference point again appears ; the compensator
used in most sugar instruments is shown on an enlarged scale in Fig. 235 ; it
consists of a plate of levo-rotatory quartz c, and of two wedges of dextro-rotatory
quartz, a and I ; by means of a rack and pinion gear one of the wedges is capable of
being slid past the other, so that the combined thickness of the system is capable
of being varied ; on the moving wedge is fixed a scale graduated in single
degrees from — 30 to + 105 ; on the fixed plate of quartz is mounted a vernier.
When the scale is at zero, the combined thickness of the dextro-rotatory
wedges a and b is equal to that of the levo-rotatory plate c, so that the effect
of the system is zero. By sliding the scale towards the 100 point a diminished
thickness of dextro-rotatory quartz is introduced, so that the effect of the system
is levo-rotatory, and at the 1 00 point exactly neutralizes the rotation produced by
the normal weight of sugar dissolved in 100 c.c., and observed in a 20 cm. tube.
Reading the Scale. — The scale of these instruments is shown in
Fig. 236 ; it consists of two parts, the lower one fixed, and the other sliding,

and moved simultaneously with the « — 1

adjustment of the compensator. The ..It I. I.I. i J J I I. I. I J.I ,1 J J J-l I ', U
line at which the reading is taken

1111111

is that marked 0 in the upper scale. FIG. 236.

At the zero position this line is continuous with that line marked 0 in the
lower scale. To take a reading the position of the zero line on the upper scale
is noted with respect to the lower scale. In Fig. 236 this is between 26
and 27. It is next observed what lines on the two scales are continuous ; in
this case the seventh, counting from zero. The full reading is then 26-7.

434

THE POLARISCOPE AS APPLIED TO SUGAR ANALYSIS.

External Form of Polariscopes. — The instruments most
frequently met with in sugar houses are made by Schmidt & Haensch, Fric, and
Peters. Fig. 237 shows a late pattern adopted by the first-named firm : at the
end next the lamp is a tube with a diaphragm in which may be inserted at will

a ground glass disc ; by the use of this, equal illumination can be obtained when
using an electric light or incandescent mantle. At B is a chamber serving to
hold a cell which may be filled with a dilute solution of potassium bichromate ;
at P is contained the polarizing apparatus ; at It is the trough of the instru-
ment designed for the reception of the tube containing the sugar solution ,

435

CANE SUGAK.

within the dust-proof casing G is contained the system of quartz wedges
forming the compensator ; FIB the telescope which focusses the field of vision;
in the enlarged part of F, i.e., between the letters F and G is the analyser ;
M is a telescope whereby the scale is read, it being illuminated from the lamp
light passing through the aperture in the light shield at £. The pattern
shown is a double wedge compensating instrument, the milled head controlling
the working wedge being seen at A ; the extension of this to the table saves
much fatigue where many consecutive analyses are made.

The pattern adopted by Peters is shown in Fig. 238 ; in arrangement of
parts it is nearly identical with the pattern adopted by Schmidt & Haensch.
The instruments made by Messrs. J. & J. Pric (Fig. 239} are also similar
to the above in arrangement of the optical parts ; the scale illumination is,

FIG. 238.

however, made differently. Within the body of the instrument, next
to the source of light, is a reflector, inclined at 45° ; a diaphragm therein
allows light to pass on to the polarizer ; the other part of the light is
reflected to a vertical silvered mirror which throws a pencil of light on
the scale.

Adjustable Landholt-Lippich Polariscope.8 — As usually
made, these instruments, when designed specially for saccharimeters, have a
fixed half shadow angle ; the smaller the half shadow angle the less is the
intensity of light, and the greater is the delicacy of the instrument ; very
light-coloured solutions can be read with a low intensity of light, but for dark-
coloured solutions it is often advisable to increase the half shadow angle, and

436

THE POLARISCOPE AS APPLIED TO SUGAR ANALYSIS.

to sacrifice the delicacy of the reading in order to obtain the passage of more
light, the accuracy of the observation being thereby increased. An instrument
using the Landholt- Lippich half shadow device, and in which the half shadow
angle can be varied at will, has been devised by Bates, and constructed by the
firm of J. and J. Fric. The analysing nicol and the polarizing nicol are
mounted in bearings, and are joined by gears with a connecting rod ; the gears
are controlled by the rotation of a milled head, and are such that the rotation
of the analyser is always twice that of the polarizer. A scale attached to the
milled head gives the half shadow angle.

FIG. 239.

The zero of the instrument is affected by a change in the half shadow
angle ; with an instrument adjusted for a half shadow angle of 10°, the latter
may be varied from 4° to 12*4° with the introduction of an error of less than
•1 Ventzke. Bates has worked out the corrections to be made for different
half shadow angles when the instrument is in adjustment for the latter equal
to zero, and this can be made practically instantaneously, the half shadow
angle being indicated as already mentioned.

437

CANE SUGAR.

It is claimed that the polarization of the better grades of sugar can be
read with this instrument to -01 Yentzke.

Optical Parts Of Polariscopes. — Below are mentioned the arrange-
ments of the optical parts of such polariscopes as are to be found in general
use.

Soleil-Duboscq. — The optical parts are shown in Fig. 2!±0 : a, colour
compensator ; I, lens to make rays of light parallel ; c, polarizer ; d, biquartz
plate ; e, compensator ; /, analyser ; k g, focussing telescope. The colour
compensator consists of a nicol prism and plate of quartz. When dark-coloured

FIG. 240.

F,o. 24!.

H 10

FIG. 242.

13 (5 E3 HH C^IZI I P.O. 243.

ft g a e c 6

H G) 123 IZ1 I n°. 244.

ft g •& c b

solutions are being examined the transition tint does not appear, but an
approximation thereto may be obtained by rotating the colour compensator.
The scale of this instrument is not provided with a vernier, divisions of
less than one degree being estimated by the eye ; the normal weight is
16*35 grms.

Soleil-Ventzke-Scheibler. — The optical parts are shown in
Fig. 241 ', reference being as in Fig. 8J/.0 ; the colour compensator is placed
next to the lamp, and in mechanical details this instrument is superior to the
Soleil-Duboscq.

438

THE POLARISCOPE AS APPLIED TO SUGAR ANALYSIS.

The Jellet-Cornu Half Shadow.— The optical parts are shown
in Fig. 2/J.2, the reference being as in Fig.

The Landholt-Lippich Half Shadow. — The optical parts are
shown in Fig. 2!j.3.

The Landholt-Lippich Triple Shade.— The optical parts are as
for the half shadow, except forthe polarizer, which is shown in Fig. 2!j.5 two small
nicols of exactly similar construction and adjustment are used so that the field
is divided into three parts ; in all positions except when
equality is obtained there appears a black band in the centre
of the field, bounded by a light portion on either side, or
vice versa ; this device is of great sensitiveness, but, owing to
the great delicacy of the adjustment of the reference point
device, is not to be recommended for use where access to an
optical instrument expert is difficult.

The Laurent Half Shadow.— The optical parts
of the early Laurent instruments are shown in Fig. 244'-,
these instruments used the sodium light and compensated by
rotation of the analyser; the normal weight was 16-19 grms.
in 100 true cc. FIG. 245.

The modern form of the Laurent instruments is shown in Figs. 2!j.6 and
247 ; these instruments are now made so that by an adjustment either the
sodium light or white light may be used ; in the former case, compensation is
effected by rotation of the analyser, and in the latter by quartz wedges.

Laurent instruments are constructed in which the lamina of the quartz
securing the half shadow device is inserted as a circular disc, concentric with
the field of vision.

Polariscope Lamp. — When ordinary white light is used it is
essential that it be as bright as possible ; an ordinary duplex paraffin lamp,
carefully trimmed, gives good results ; better results still are obtained by an
incandescent mantle with gas or alcohol as the source of light, and the
acetylene lamp gives perhaps the best illumination. The incandescent electric
light is also convenient, but requires the interposition of a ground glass disc.
Some years ago lamps supplied from the makers of polariscopes were fitted
with a metal chimney, in which was a bull's-eye lens. This is not only
unnecessary, but even objectionable; it is, however, convenient to enclose the
source of light in an asbestos chimney provided with a narrow opening,
towards which the polariscope is directed ; this arrangement is to shield the
eye of the observer from extraneous light. The distance of the lamp from the
instrument is of importance, and in modern instruments it is from 15 cm. to

439

CANE SUGAR.

20 cm. ; actually, the lamp should he so placed that an image of the source of
light is formed "by the illumination lens on the analyser diaphragm. This
position can he easily determined ; a pencil point is held immediately in front
of the source of light, and a piece of paper in front of the diaphragm ; at
the correct position a sharp image of the pencil point is formed on the paper.

In most text hooks it is recommended that the polariscope he used in a
dark room, and sometimes that the source of light be in a separate room, a
narrow slit being cut in a wall of the room. In general this scheme is
inconvenient, and confinement in such a place is, in the tropics, objectionable
The writer finds that extraneous light may readily be excluded from the eye
by the following device : — A piece of copper is beaten out into the form of the

440

THE POLAEISCOPE AS APPLIED TO SUGAR ANALYSIS.

cups used to apply eye washes, and a sprung shank is soldered on to this cup,
forming a piece as in Fig. 2/j.S ; this is fixed on to the focussing telescope, the
size of the shank being such that it allows the telescope tube to rotate easily
within it.

Variation in Optical Activity of Quartz.— The optical
activity of quartz increases with the temperature, and is expressed, according
to Jobin,10 by the equation a* = a° (I + '000146£), where a* is the specific
rotation at t, and a° that at a lower temperature. Hence, if a quartz wedge
compensating polariscope, adjusted at the standard European temperature of
20° C., be used in the tropics at a temperature of 30° C., a less thickness
of quartz will be required to compensate for the rotation of a sugar solution.
This error is small but still appreciable. Suppose at 30° C. a reading of 96-0
be observed, then at 20° C. the reading would be 96 (1 + -000146 X 10)
= 96.14.

Fm. 247.

Similarly, a quartz control plate standardized at 20° C. will give the same
reading at 30° C. in a quartz wedge compensating instrument, but will give a
higher reading at the higher temperature in an instrument compensating by
rotation of the analyser.

Polariscope Tubes. — The older form of polariscope tube is shown
in Fig. 2!±9. It consists of a glass or metal tube, the ends of which are ground
exactly flush. In filling a tube with a solution for observation a glass disc is
placed on one end and secured in position by screwing on a metal cap. The
tube is held vertical and the solution is poured in until it fills the tube, and
rises by capillarity over the upper surface ; a second glass disc is then slid on
and secured in position by a metal cap.

441

CANE SUGAR.

In the later, more convenient form of tube, Fig. 250, the discs are held in
position by spring metal caps. The Laurent instruments use a bayonet spring
catch. The objection to the use of screw metal caps is the danger of producing
a strain in the glass discs, whereby they themselves become optically active.

Pellet's Continuous Tube.11— This con-
sists of a tube, Fig. 251, provided with a syphon
overflow. The solution under analysis is contained in
the beaker a ; on opening the spring clip b* the
solution already in the tube is displaced and its
place is taken by that flowing in from the beaker a.
Until all the material originally in the tube is dis-
placed by that entering, a reading cannot be obtained, due to the formation
of striae. By arranging a wire cradle connected to and alongside of the
trough of the polariscope, the Pellet tube can be rolled out if it is desired
to introduce another tube. The Pellet tube effects a great saving of time
when many consecutive analyses have to be performed, in fact it is hard to
say why every sugar laboratory does not use this device.

FIG. 248.

FIG. 249.

Water Jacketed Tube. — In the Clerget analysis, where the control
of the temperature is of importance, the tube shown in Fig. 252 is convenient ;
it is filled through the aperture in the middle after both of the end caps have
been placed in position ; a thermometer is inserted through the same aperture
to take the temperature of the solution. A continuous current of water may,
if necessary, be made to flow through the jacket, and readings at an elevated
temperature obtained.

FIG. 250.

Value of Scale Degree. — In polariscopes the scale is divided
into 100 equal parts on the assumption that the rotation of cane sugar
is independent of concentration. The following table gives the value of each
degree of the polariscope scale calculated from the Schmitz determinations of
the rotation of cane sugar at varying concentration, and in refined analyses

*This clip is more conveniently placed on the delivery tube and resting on the table.

442

THE POLARISCOPE AS APPLIED TO SUGAR ANALYSIS.

these factors should be used in place of the normal weight, taken here as
26 grms. per 100 true cc. : —

Corrected Normal
Weight.

Polariscope reading
in 20 cm. tube.

Polariscope reading
in 20 cm. tube.

Corrected Normal
Weight.

5

10
15
20
25
30
35
40
45
50

25-90
25-92
25-93
25-94
25-94
25-94
25-95
25-95
25-95
25-96

55
60
65
70
75
80
85
90
95
100

25-96
25-97
25-97
25-97
25-98
25-98
25-99
25-99
25-99
26-00

Control of Scale. — Quartz plates, the exact value of which has
been determined in sugar degrees, may be obtained from makers. These plates
are standardized at 20°C. in Europe, and as they are equally affected by
variation of temperature with the quartz wedge they will serve at any

FIG. 251.

temperature to control the scale of a polariscope of this type ; but if used to
control the scale of a polariscope compensating by rotation of the analyser, the
correction for temperature must be applied.

A control observation tube by Schmidt and Haensch is shown in Fig. 253 ';
it consists of an outer tube, T, in which is moved by means of a rack and pinion
gear the tube /, fitting closely into T, exit of liquid between T and / being
prevented by the washer e ; the tube / is closed by a glass disc at c. The
solution to be used for testing is poured into the funnel a, whence it fills the
tube T. The distance between d and e is regulated by the rack and pinion
gear, the exact distance and also the length of the column of liquid being read
off a scale carrying a vernier ; the tube is conveniently filled with a solution
of the normal weight of sugar in 100 cc. ; with a column of liquid 20 cm.
long a reading of 100 should be obtained, and other readings should be pro-
portional to the length of the column of liquid. A very rapid control over

443

CANE SUGAR.

the scale can thus be obtained ; of course the scale can also be tested by
polarizing different weights of pure sugar in a tube of constant length, but
this, compared with the adjustable control tube, is a laborious operation.

It is a principle in analysis that every piece of apparatus should be
standardized twice, once by the maker and once by the user. The method

FIG. 252.

employed by Harrison12 in the British Guiana Goverment Laboratory is as
follows : —

" Each 100 cc. flask in use for sugar polarization is verified by weighing
into it 99-533 grins, of recently boiled distilled water at 28°C. The exact
weight of chemically pure sugar, which when made up to a bulk of 100 cc.
in one of the corrected flasks at 28°C. gives a polarization reading of 100°, is
ascertained by experiment for each instrument, and this weight of sugar is
invariably used instead of the maker's normal weight for 17'5°C."

FIG. 253.

Double "Wedge Compensator. — Two sliding wedge compensators
are fitted to the instrument ; the milled head controlling one is coloured black,
and the other red ; the observation is made in the usual way with the black
compensator; the active solution under analysis is then removed and neutrality
obtained by adjusting the red compensator ; the readings on the red and black
scales should be identical, practically demonstrating the accuracy of the
reading, for it is very unlikely that an identical error should be made twice

444

THE POLARISCOPE AS APPLIED TO SUGAR ANALYSIS.

running, or that both compensators should possess the same error in
construction. The arrangement of the wedges is shown in Fig. 25^..

Saccharimeters are usually only provided with a scale reading to — 30° ;
with this device, by setting the zero of the red scale to the right, minus
readings of any value can be obtained.

Use of Light Filter with Quartz Wedge Compensa-
tion.— The application of the quartz wedge to compensate for the rotation of
sugar solutions is only possible because of the near coincidence of the rotation
dispersion of cane sugar and of quartz ; actually, the violet rays are a source
of error, and these may be shut off by passing the light through a crystal, or
through a dilute solution, of potassium bichromate. With dilute solutions the
effect of the violet rays is barely appreciable, but they become noticeable
(destroying the sensitiveness of the end point) at readings near the 100 point.
Some instruments are provided with a cell to be placed between the lamp and
the polarizer, which is filled with a dilute solution of potassium bichromate,
and in other patterns a plate of bichromate is inserted in the ocular of the
focussing telescope. This light filter should always be used when the incan-
descent gas or acetylene light is used.

The disturbing effect of the violet rays is especially
noticeable when solutions of glucose are being observed.

Adjustment of the Polariscope. — Zero
Adjustment. — After having obtained the end position

with no active material in the body of the instrument.
FIG. 254.

the scale should read zero. If another reading is obtained,

the scale can be adjusted to zero by rotating a square headed pin located in
the Schmidt & Haensch and Peter's instruments at the side of the dust proof
casing of the compensator ; in the Fric instruments this pin is placed on the
top of the dust proof casing. A key fitting the pin is supplied with the
instrument.

Analyser Adjustment. — In case a sharp end point cannot be found the
analyser must be adjusted. In the earlier instruments, underneath the barrel
containing the analyser, will be seen a pin ; this pin carries a worm gearing
with a wheel cut on the sleeve containing the analyser ; rotation of this pin
by means of the key mentioned above controls the position of the analyser, the
best position of which must be found by trial and error.

In other instruments, on each side of the tube containing the analyser,
will be found two screws with projecting heads. These screws have conical
points bearing eccentrically on the edges of two holes bored in the
rotating sleeve carrying the analyser. To adjust, both screws are loosened
and one screw is slightly turned, the end point is then found by altering the
position of the quartz wedges. If a sharper end point is found the screw has

445

CANE SUGAR.

been turned the right way, and by trial and error the sharpest end point is
found ; after it has been determined the screw which was not used in the
adjustment is tightened until it just bears on the sleeve, after which the
second screw is turned home ; the scale adjustment to zero is then made.

In other instruments the analyser is held in a brass tube which rotates
easily within an outer tube forming the casing of the instrument ; on the
casing is formed a slot covered by a collar ; two pins pass through the collar
and slot and screw into the tube which carries the analyser ; by loosening the
screws the analyser can be rotated about its longitudinal axis through
the length of the slot.

Polarizer Adjustment. — The instruments employing the Jellet
prism have the polarizer fixed in position ; the instruments employing the
Lippich polarizer are capable of adjustment in both polarizer and half prism ;
the former is capable of rotation by the last-mentioned device above. The half
prism is usually capable of two adjustments laterally by means of three screws
which pass through the casing ; two of these screws pass into the holder of
the half prism, and one bears on the holder ; rotation of the half prism is
effected by a system of screws and slots substantially as described above.

In the Schmidt & Haensch triple shade instrument one of the half prisms
is capable of adjustment by means of coned screws bearing eccentrically on the
holder of a half prism ; adjustment is made by trial and error as described for
the analyser; this adjustment is necessary when the outer portions of the
triple field are unequally in shadow.

Adjustment of the prisms is a delicate operation and should only be
undertaken when absolutely necessary, but no damage need be anticipated
when the theory of the instrument is understood and when care and patience
are used. If an old disused instrument is available, it is better first to acquiie
familiarity with the construction from manipulation of its parts.

REFERENCES IN CHAPTER XXI.

1. This chapter is based on Landholt's classical treatise: " The optical

Rotation of Organic Substances."

2. Ann. Chem. Phys., 1840, p. 401.

3. Brit. Assoc. Report, 1860, p. 13.

4. Bull. Soc. Chem., 1870, p. 140.

5. Zeits. fur lustrum., 2, 167; 14, 326.

6. Dingler's Poly. Jour., 1897, p. 608.

7. Bull. Assoc., 19, p. 101.

8. Ueber ein neues Polaristrobometer. Bern, 1865.

9. /. S. J., 108.

10. Zeit. fur Rub. Ind., 1898, p. 835.

11. Zeits. fur Rub. Ind., 1891, 338.

12. Jour. Roy. Agric. Com. Soc. Brit. Guiana, December, 189 o.

446

CHAPTER XXII.

THE OPTICAL ASSAY OP SUGARS.

The optical assay of sugar is based on the direct proportionality of the
rotation of a ray of polarized light to the concentration of the solution, and to
the length of the layer through which the polarized ray passes. Hence if the
rotation of a ray of polarized light be measured for any known concentration and
length of layer, determination of the rotation and length of the layer of the
solution afford data to calculate the concentration ; further, in case the material
under examination is a solid, the solution of a known weight of the material
in a definite volume and determination of the rotation under known conditions,
give data to calculate the percentage of sugar in the material under
examination.

The instruments used for this purpose are known as polariscopes, and are
discussed in Chapter XXI. ; in this Chapter the general principles of the
process are outlined ; their application to different products of the sugar
house is developed in Chapter XXIII.

The Clearing Agents used.— In general sugar solutions are
unfitted for polarimetric assay without the addition of some agent to precipitate
colouring and other bodies, which render the solution turbid. The materials
in general use are : —

1. Alumina Cream. — Solutions of high grade sugars are often sufficiently
clear for polarimetric assay except fora slight turbidity which may be removed
by agitation of the solution with a little alumina cream and subsequent
filtration ; alumina cream is prepared thus : — Precipitate a solution of an alum
with a slight excess of ammonia ; wash by decantation till all soluble matter
is removed, and preserve as a thick cream.

2. Precipitation of alumina within the solution.1 — The precipitation of
alumina within the solution has a much greater decolourizing effect than the
addition of alumina cream, and the effect is increased by the addition of very
small quantities of hydrosulphites. As carried out by the writer the clarifi-
cation is thus made : to a measured quantity of the solution under analysis a
quantity of a solution of sodium aluminate is added, and after mixture
followed by an equivalent quantity of a saturated solution of aluminium
sulphate and about '05 grm. of sodium hydrosulphite. The aluminate and
alum solutions are previously standardized against each other, using phenol -
phthalein as an indicator.

447

CANE SUGAR.

With this method with sugars and juices a filtrate is obtained as .much
decolourized as by the use of basic lead acetate. Waste molasses cannot be
satisfactorily observed in greater than '25 normal solution.

Normal weights of sugars require from -5 to 1 cc. of a saturated solution
of alum, and molasses in *25 normal weight, from 2 cc. to 3 cc.

3. Basic Acetate of Lead has formed the most general clarificant of sugars.
It is used by adding a concentrated solution to the solution of sugar under
analysis. For 26 grms. of refining sugars from *1 to 1 cc. of lead acetate
solution, sp. gr. 1'25, are necessary; for the same quantity of molasses up to
15 cc., and for 100 cc. of juice up to 6 cc. An excess of lead acetate must
not be used. The material is thus prepared : 264 grms. litharge are digested
with 440 grms. neutral acetate of lead until dissolved and made up to
2000 cc.

4. Neutral Acetate of Lead is used precisely as the basic acetate, but its
use is limited to such products as are light-coloured.

5. Calcium Hypochlorite is used by Zamaron2 in conjunction with neutral
acetate of lead. 625 grms. of calcium hypochlorite are shaken with 1000 cc.
of water, and the filtered solution, which should mark 1 8°- 20° Beaume, pre-
served for use. Pellet uses 20 cc. of this in conjunction with neutral lead
acetate to decolourize 4 grms. of molasses.

6. Dry Basic Acetate of Lead. — This material was introduced by Home3
to counteract certain errors occasioned by the use of a solution of lead acetate.
The dry acetate, together with a little sand, is added to the solution of sugar
after it has been made up to definite volume. For 26 grms. of sugar about
0-5 grm. of this material is required.

7. Charcoal. — Bone charcoal added to sugar solutions exercises a powerful
decolourizing effect, but, as it at the same time absorbs an appreciable quantity
of sugar, it is little used. It has been recommended to filter the sugar
solution through charcoal and to collect separately the later runnings after the
charcoal has absorbed all the sugar that it is capable of doing.

Basic Nitrate of Lead is recommended for use by Herles. Two solutions
are used: — a. 2000 cc. water and 90 grms. caustic soda; b. 2000 cc. water
and 1000 grins, lead nitrate. The lead solution is added to the alkali
immediately before use in the proportion of 1 of lead to 1*0 to Tl of alkali.
"With this solution [it is stated that the readings are not affected by an
excess and that lead does not pass into solution. It has not come into any
general use.

8. Mercuric Compounds exercise an effect similar to that of lead with
the distinction that they precipitate amides from solution. They are not in
general use in sugar analysis, but very recently Andersen4 has recommended
for use as a clarificant the following solution : 220 grms. HgO, dissolved in
160 cc. HN03, sp. gr. T39, and made up to 1000 cc. with the addition of

448

THE OPTICAL ASSAY OF SUGARS.

60 cc. of a 5 per cent, solution of caustic soda; the material after addition
to the sugar solution is immediately neutralized. It is stated that an excess
has no action on the opticity of the sugars.

The Effect of the Precipitate produced by Lead
Compounds in Clarification. — In the majority of the ahove detailed
schemes for clarification aa insoluble precipitate is formed which occupies an
appreciable volume, so that if, after clarification, the solution be made up to
100 cc. the actual volume is 100 cc. less the volume occupied by the precipi-
tate ; prima facie, an error is thus introduced, though that this is the case
is denied by certain chemists. H. Pellet5 in particular claims that the
precipitate formed by the addition of basic acetate of lead entrains sugar, and
that this entrainment compensates for the volume occupied by the lead
precipitate. In his experiments he shows that a weight of sugar material
dissolved in water and made up to 100 cc. in the presence of its precipitate
gives a reading of, say, 50°, the same weight of sugar material made up to
200 cc. in the presence of its precipitate will give a reading exactly half the
first, in this case, 25° ; if the lead precipitate exercised an influence propor-
tional to its volume the first solution would be more than twice as concentrated
as the second, and hence the first reading should be more than twice as large as
the second ; this phenomenon he attributes to the entrainment of sugar by the
lead precipitate, and claims that it is unnecessary to apply a correction for its
volume.

The writer in investigating the same subject found also that a fixed weight
of sugar material made up to different volumes in the presence of the precipi-
tate tends to give identical polarizations independent of the dilution, and
explains the apparent non-influence of the lead precipitate by an increase in
the specific rotation of cane products with dilution.

Home's very detailed experiments6 also point to the conclusion that the
lead precipitate introduces a positive error and that sugar is not entrained.

Correction for the volume of the lead precipitate is made by the following
methods : —

1. ScheiUer's Method.1 — The material under analysis is first made up to a
volume of 100 cc. in the presence of its precipitate, and the reading taken; a
second reading is taken under identical conditions, except that the volume
is now made up to 200 cc.

Let x be the volume of the precipitate; let a be the reading in 100
apparent cc., and 5 the reading in 200 apparent cc.

Then (100 — x) a — (200 — x) I.
Solving this equation x is found.

Assuming that there is a change in the rotation of cane products with
dilution this method is inaccurate, and the writer modifies it thus :

449

29

CANE SUGAR.

The material under analysis is first made up to 100 cc. in the presence
of its precipitate, filtered, and 50 cc. of the filtrate diluted to 200 cc.,
and the reading observed ; let it be a. The same weight of material is
made up to 200 cc. in the presence of its precipitate, and the reading taken;
let it be b ; let the volume of the precipitate be x • the two readiugs to be
observed are now almost exactly at the same dilution ; then 2« (100 — a?) =r
(200 — x) I.

Solving this equation x is found.

2. Method of Sachs.9 — The precipitate obtained is collected on a filter and
washed until free from sugar ; it is then transferred to a graduated flask into
which is weighed a sugar of known polarization. This weight of sugar is
then made up to an apparent definite volume in the presence of the precipitate
and a polarimetric reading taken. The apparent increase in the polarization
of the sugar affords data to calculate the volume of the precipitate.

3. Wiechmanri's Method.9 — The precipitate is collected, washed free of
sugar, dried and weighed. Its specific gravity is then obtained with the
pycnometer, benzene being the liquid used ; from its weight and density the
volume of the precipitate is calculated.

4. Home's Method.10 — Home eliminates the error due to the volume of
the lead precipitate by making the solution of sugar product up to definite
volume, and clarifying by the addition of dry basic acetate of lead in
powdered foim, and assuming that the volu^ne of the acetic radical which goes
into solution is compensated by the volume of the material precipitated. This
method has met with considerable approval.

The Presence of Active Bodies other than Sugar.— The

active bodies other than cane sugar present in cane products are chiefly dextrose
and levulose; mannose and raifinose in small quantities have also been
reported, and small quantities of gums are also present. The disturbing
influence of dextrose and levulose is removed by the Clerget method, and the
other bodies are generally present in such small quantities as to be negligible.

The Effect of Lead Acetate on the Opticity of Sugar.—

The effect of lead acetate on cane sugar is small, and is given by Bates
and Blake11 as under, pure sugar being tested in normal concentration

Basic lead
acetate added,
cc.

Difference in
Polarization.
Ventzke0.

Basic lead
acetate added,
cc.

Difference in
Polarization.
Ventzke0.

•5

—0-09

4-0

—0-06

1-0

—0-13

5-0

—0-93

1-5

—0-10

6-0 ..

—o-oo

2-0

—0-13

7-0 . .v

+0-05

2-5

—0-06

8-0 .;,

+0-09

3-0

—0-08

10-00 . -...^

+0-19

450

THE OPTICAL ASSAY OF SUGARS.

The Effect of Concentration on the Rotation of Sugars. —

The rotation of cane sugar is but little affected by dilution ; there is, howeverr
a sensible rise in the specific rotation with dilution.

The results of Schmitz12 (which are those most often quoted) and of
Nasini and Yillavecchia 13 are in close agreement. If p is the percentage of
sugar, and c the concentration in grms. per 100 cc., then, according to

Schmitz,

p — 5 _ 65 ; [•] V) == 66-510 -f -004508^ - -00028052^2

c — 2-5 to 28 ; [*] ^? = 66-639 — '0208200 + -00034603/?2
and approximately, for purposes of calculation,

o — 2-5 to 28 ; [a] 2? = 66-541 — -0084150.
Nasini and Villavecchia found

p — 3 to 65 ; [a] 20 — 66-438 + 010312;? — -00035449p2.

In very dilute solutions the results of investigators are contradictory.
Tollens14 found quite irregular values, Pribram15 found a decrease in falling
from^? •=. 3-659 to -222, whilst Nasini and Yillavecchia found an increase in
falling from^ = 1-253 to -824.

The specific rotation of dextrose increases with concentration, and is thus
expressed by Tollens16 for the anhydrous body

[a] 20 — 52-50 + -018796^ -f -0005168^2.

The rotation of levulose also decreases with dilution. Honig and Jesser17
give the formula for c •=. 60 to 95 per cent.

[a] 20 = -113-96 + -2580,
c being the percentage of water in the solution. This reduces to

[a] 2£ =-(88-16 + -258^).
Ost found the effect of dilution to be expressed by the formula

[a] 20 = — (91 -90 + -llty) for values of p 1 to 30 per cent.

The Effect of Temperature on the Rotation of Sugars.—

The effect of temperature, having a very considerable bearing on the valuation
of sugars, has been much studied, and very discordant results have been
recorded. A very complete bibliography of the question is given by Wiech-
mann.18 With very few exceptions it is now generally accepted that the
rotation of cane sugar decreases with rise in temperature. "Watts and
Tempany19 in a series of very careful experiments found this relation to hold

451

CANE SUGAR.

for quartz wedge compensating instruments, the corre ction including that
known as Jobin's.

True polarization — (1 + -00039Q observed polarization,
where t is the difference between the temperature of observation and that at
which the instrument was graduated in C°.

This result is in very close agreement with those obtained by Harrison
and by Wiley.

The rotation of levulose falls very rapidly with temperature rise. Honig
and Jesser17 give for p = 9 and t = 13°C. to 40°C.

[a] J = — 103-92 + -671*
and for p — 23-5 and t — 9°C. to 45°C.,

[a] * =—107-65+ -692*
Jungfleisch and Grimbert20 combine temperature and concentration in the one

formula

[a] * = — [101-38 — -56* + -108 (c— 10)]

e being the concentration in grms. per 100 cc.

There do not appear to be any results published connecting the
temperature and rotation of dextrose.

The Effect of Inactive Bodies on the Rotation of
Sugars. — A small decrease in the rotation of cane sugar is brought about by
the simultaneous presence of any of the following bodies :

Hydrates of the alkalies and alkaline earths.

Chlorides, nitrates, sulphates, carbonates, phosphates, acetates and citrates
of the alkalies.

Eorax, magnesium sulphate.

Chlorides of the alkaline earths.

An increase is observed with formaldehyde.21

In the quantities in which these bodies occur in routine analyses the effect
is very small.

In the presence of lead acetate the specific rotation of levulose decreases
until it becomes dextro-rotatory, and in the presence of mineral acids it
increases (v. Clerget Process).

Bl-rotation. — The initial rotation of many of the sugars when freshly
prepared is much higher than that after standing some time. After standing
24 hours a constant end rotation is obtained ; it is also rapidly obtained on
heating, and by the addition of certain bodies in minute proportion, e.g.,
ammonia.

452

THE OPTICAL ASSAY OF SUGARS.

Specific Rotation of Bodies other than Cane Sugar,
Dextrose, and Levulose, occurring in Sugar Analysis. —

For convenience of reference some of these are here collected : —

Eaffinose ...... [a] j) — 104'2 t = 2Q (t = temperature.)

Maltose ...... [a] * = 140-375 — -01837^ — '095£

(p = per cent, of material.)
Isomaltose gallisin . . c= 10-60 [a] 2? = 82-76

e= 27-29 La]2? = 80*10

c— 54-58 [a]20 = 77-32
Lactose ...... HJ)~ 52'5 t = 20

Mannose ...... [«] * = 12-96 t = 20

Galactose ..... [a] * = 83037 + -199p — (-276 — -0025^?) t,

— 5 per cent, to 35 per cent, and t =: 4° C to 40° 0.
Arabinose ...... [a] = 104-4 0 = 10 * = 18

(c = concentration in grms. per 100 c.c.)
Xylose ...... WT>= 18-095 + -06986^ p = 3 to 34

Dextran ...... [a] = 230

Levulan ...... [«] = -221 £ = 20 c = 5 to 30

Xylan ........ [«] = 70 to 85

Direct Polarization. — The optically active constituents of the cane
sugar factory consist essentially of cane sugar, of dextrose, of levulose, and of
small amounts of other sugars ; in many cases the combined optical effect of
the reducing sugars is small and may even altogether vanish, so that it is very
general to calculate the result of the analysis as if cane sugar was the only
active body present. Results so obtained are referred to as sugar from direct
polarization. The effect of optically active bodies other than sugars can be
eliminated by the Clerget process described in the next section.

The Determination of Sugar by Cler get's Process.—

A solution of cane sugar when heated with acids is quantitatively converted
into equal parts of dextrose and of levulose, and a solution of cane sugar
originally dextro-rotatory is after such treatment found to be levo-rotatory.
Clerget observed that the two rotations bore a fixed ratio to each other when
the conversion of the cane sugar into dextrose and levulose was performed
under fixed conditions. His original process was as under22 : 16-471 grms. of
sugar were dissolved in water, transferred to a flask graduated at 100 and at

453

CANE SUGAR.

110 c.c., water added to the 100 mark and the volume completed to the. 110
mark with strong hydrochloric acid. After mixture the flask was placed in a
water bath and heated in such a way that at the end of fifteen minutes the
temperature had risen to 68°. The flask was then removed, rapidly cooled,
and its contents polarized in a tube 220 cm. in length to allow for dilution.
Clerget found that a solution of 16-471 grms. of sugar per 100 c.c., which
polarized 100° in his polariscope, gave at a temperature of 0° a reading to the
left of 44°, the rotation decreasing '5° for every 1° rise in temperature.

Hence followed the formula * = — — — where s is the true percentage of

sugar, and a and I are the readings before and after inversion referred to the
same concentration, and t is the temperature of the observation.

This method of making the inversion is not now generally followed,
the official German instructions due to Herzfeld being as under23 : —

The half-normal weight (13-024 grms.) is taken and dissolved in a 100 c.c.
flask in 70 c.c. of water, 5 c.c. of hydrochloric acid of 1-19 specific gravity is
added, and the flask and its contents warmed to 67° — 70°C. and maintained at
that temperature for five minutes, at the expiration of which time the maximum
left rotation is obtained ; the flask is then rapidly cooled, its contents com -
pleted to 100 c.c., and polarized at a temperature as close to 20°C. as possible.
A rise of temperature above 70°C. or a prolonged heating invalidates the
results, and in the use of this process the directions must be exactly followed.

Herzfeld found that the Clerget constant varied with the concentration of
the sugar, and constructed the following table : —

Grms. Sugar
per 100 c.c.

Constant.

Grms. Sugar
per 100 c.c.

Constant.

1

141-85

11 ..

142-52

2

141-91

12 .. . ..

142-59

3

141-98

13

142-66

4

142-05

14

142-73

5

142-12

15

142-79

6

142-18

16

142-86

7

142-25

17

142-93

8 . .. ...

142-32

18

143-00

9

142-39

19

143-07

10

142-46

20 .. .. ;.

143-13

Por the half -normal weight the factor is 142-66, which is the now
generally accepted Clerget constant. The variation can also be expressed in

the formula * = — — : -7- where i is the reading after inversion in

141'84+To-l

the 200 cm. tube without any correction. It will be observed that the
constant here given varies much from that found originally by Clerget. In the

454

THE OPTICAL ASSAY OF SUGARS.

original Clerget process the concentration of the acid and of the sugar is
greater than it is in that due to Herzfeld, and since the levo-rotation of
levulose increases with concentration and with increasing strength of acid, a
higher value for the constant is obtained. This point is of extreme importance
and is one which is perhaps not uncommonly overlooked.

Of greater importance than the concentration of the acid is the tempera-
ture factor ; the temperature should he observed at the moment of making a
reading, the water-jacketed tube referred to in the previous Chapter being used.

Irregularities in the Clerget Process and Colour of
Solution after Inversion.— In certain cases, especially with low grade
molasses, the solution becomes so dark coloured after inversion that it can only
be read with great error or in a state of high dilution ; this inconvenience may
be overcome thus.

a. To the solution after inversion a Kttle bone charcoal is added, the
whole shaken and filtered ; absorption of the reducing sugars does not occur.

I. To the solution as it cools is added a crystal of sodium sulphite ; the
sulphur dioxide generated decolourizes the solution.

c. To the solution as it cools a little zinc dust is added, the decolouration
being now due to the nascent hydrogen evolved.

Effect of Lead. — In the presence of basic lead acetate the left handed
rotation of levulose decreases, the normal value being restored on neutralization.
Hence, as has been shown in particular by Tervooren,30 the direct reading
should be taken after acidification of the filtrate after clarification with basic
lead acetate. Tervooren's routine for eliminating the error in the analysis of
molasses is —

" Dissolve 35-816 (26-048 X £ X f X |J) grms. molasses in 250 cc.
water, with the addition of 40 cc. basic lead acetate ; receive 100 cc. of the
filtrate in a 100-110 cc. flask; add 1 cc. of 30 per cent, acetic acid and
2 cc. of alumina cream, make up to 100 cc., then filter and polarize. The
reading multiplied by 2 is the direct reading."

Increase in Rotation of Levulose. — In the presence of hydrochloric acid the
gyrodynat of levulose increases; hence when levulose is initially present, a
positive error is introduced. Browne24 states that this error is corrected for by
deducting from the percentage of sugar '36 per cent, for every 1 per cent, of
levulose present, when 10 c.c. of hydrochloric acid, sp. gr. 1-18, are used per
100 c.c. of sugar solution.

Modifications of the Clerget Process.— Various agents other
than hydrochloric acid have been used to effect the inversion, such as oxalic
acid, employed in the proportion of one part per 100 of sugar at a temperature
of 50°C. — 60°C. for several hours. Yeast as an agent was first used by
0' Sullivan and Thomson25 as follows : — 50 c.c. of the solution under analysis
are raised to a temperature of 55°C. ; some brewers' yeast in quantity ^

455

CANE SUGAK.

that of the sugar present is pressed in a towel, placed in the flask, the
contents of the flask well stirred and kept at 55°C. for four hours ; clarification
is effected by alumina cream, and the whole, after making up to 100 c.c.,
filtered and polarized.

In all modifications of the official Clerget process it must be remembered
that a constant differing from the official one obtains, and that must be
determined experimentally under the same conditions as those under which an
analysis is made.

The Separation of Sugars occurring in Mixtures.— The

estimation of cane sugar in the presence of levulose and of dextrose is
performed under the Clerget process ; the estimation and separation of the
accompanying reducing sugars is thus obtained after Browne24 : —

1. The reducing power of the sugars is expressed in terms of dextrose,
the reducing power of which is put equal to unity. The reducing power of
the commoner sugars investigated by Browne is given in Chapter XXIII.

2. The optical rotation of the sugars is expressed in terms of cane
sugar, the rotation of which is put equal to unity. According to Browne2
these are —

Cane Sugar 1-000

Dextrose .. .... -793

Galactose.. .. .'.-.. .. 1-21

Arabinoso . 1-571

Xylose .". .. '283

Levulose. — The rotation varies so much with temperature that special
numbers have to be calculated for each temperature. The factors calculated
from the formula of Jungfleisch and Grimbert20 are —

Temper- Concentration,

ature. 1 per cent. 2 per cent. 3 per cent. 4 per cent. 5 per cent. 10 per cent. 25 per cent.

15 .. —1-384 .. — 1-385 ..—1-387 ..—1-389 ..—1-390 ..—1-398 ..—1-422

20 . . —1-341 . . — 1-343 . .—1-345 . .—1-346 . . — 1-348 . .—1'356 . .—1-380

25 .. —1-299 .. — 1-301 ..—1-303 .. — 1-304 .. — 1-306 .. — 1-314 ..—1-338

30 .. —1-257 .. — 1-259 .. — 1-261 ..-1'262 .. — 1-264 . —1*272 ..—1-296

Let x •=. per cent, of a given sugar A.

Let y = per cent, of a given sugar B.

Let a = dextrose ratio of sugar A.

Let I =. dextrose ratio of sugar B.

Let R =. per cent, of reducing sugars as dextrose.

Then oc + by = J2 (1)

Let a — polarization factor of sugar A.
Let /3 = polarization factor of sugar B.

Let P = polarization of mixture, i.e., reading in Yentzke scale in 20 cm.
tube for 26 grms. of sugar in 100 c.c.

Then ax + fry = P (2)

Solving these two equations the amounts of the sugars are found.

456

THE OPTICAL ASSAY OF SUGARS.

The difference between direct polarization and the polarization due [to
Clerget's process is the polarization of the dextrose and levulose in the
mixture ; the dextrose and levulose are then separated according to the
equations above.

The simultaneous Determination of Cane Sugar and
Raffinose. — The official German method due to Creydt26 is as follows : —

The direct reading is taken at 20° C.

The material is inverted according to the official Clerget process.
Let A = direct reading, B = reading after inversion, c = algebraic
difference between A and B.

Then C-

Sugar per cent. = —

Raffinose per cent. =

•81
A- 8

1-54

Pieraert's process is as follows27: —

10 grms. of material are dissolved in 100 c.c. ; this solution serves to give
the direct reading. 50 c.c. of this solution are transferred to a 100 c.c. flask,
to which are added 10 c.c. of a 20 per cent, solution of citric acid, and the
mixture boiled for 15 minutes in a flask to which is attached a reflux con-
denser ; after making up to 100 c.c. and cooling, the inverted reading is
taken. Then if x and y are quantities of cane sugar and of hydrated raffinose
in 100 c.c. of solution, and a and I are the readings before and after inversion,

x— 9-287«- 18-3113

y = 3-6590 + 11-6523

The simultaneous Determination of Cane Sugar,
Invert Sugar, and Raffinose. — The following scheme is due to
Wortmann28 : —

The reducing sugars are determined under Clerget's process, and calculated
according to the formula —

£ = —

q

R being the per cent, reducing sugars, C the weight of copper, and q the
quantity of material used.

The direct and invert readings are then obtained according to the official
German method.

Then

"9598^ - 1-85 J— 277*

Per cent, cane sugar =

Per cent, raffinose =

1-5648
A ~ 8 + '

1-85
where A and JB are the direct and invert readings.

457

CANE SUGAR.

The Effect of Temperature on the Polarization of
Sugars. — Although there is no doubt that the rotation of cane sugar falls
with a rise in temperature, in commercial sugars other factors are at work.
Browne29 has conclusively shown that owing to the presence of levulose in low
grade sugars a rise in temperature is often accompanied by a rise in
polarization, and that the application of a temperature correction is invalid ; to
obtain a just ' polarization ' all sugars should be polarized at one standard
temperature, which is in the United States fixed at 20°C. It is extremely
unfortunate that the Supreme Court of the United States has definitely settled
that legally the polarization of a sugar is the percentage of sucrose in that
sugar, and has also established the validity of temperature corrections, entirely
losing sight of the presence in commercial sugars of active bodies other than
sucrose. The polarization of a sugar is a useful trade convention but analy-
tically has no real meaning.

REFERENCES IN CHAPTER XXII.

1. /. 8. J., 92, 99.

2. Ball. Assoc. 16, 337.

3. J. A. C. S., 26, 186.

4. Abs. in Jour. Soc. Chem. Ind., 1909, 805.

5. /. 8. J., 93.

6. J. A. C. 8., 1907, 926.

7. Zeits. fur. Rub., 1875, 1054.

8. Revue. Universette de la Fabric de Sucre, 1, 451.

9. I. S. J., 56.

10. /. 8. J., 61.

11. Butt. U. S. Bur. Standards, 3, 105.

12. Ber. Deut. Chem. Gesel., 10, 1414.

13. Pub. Lab. Chem. Gen. Delia. Gab. Roma., 1891, 47.

14. Ber. Deut. Chem. Oesel, 10, 1410; 17, 1757.

15. Ber. Deut. Chem. Gesel, 20, 1848.

16. Ber. Deut. Chem. Gesel., 21^, 2000.

17. Zeits. fur Rub., 1888, 1028.

18. /. S. J., 21.

19. W. I. B., 6, 52; 7, 152.

20. Comptes rendus, 107, 390.

21. Chem. Centralblatt, 1907, p. 1320.

22. An. Chem. Phys., 1849, p. 185.

23. Zeit. Ver. Deut. Rub. Ind., 28, 699.

24. Jour. Am. Chem. Soc., 28, 4.

25. Trans. Chem. Soc., 1891, p. 46.

26. Zeit. fur Rub. 2nd., 38, 867.

27. Bull. Assoc., 23, 1143.

28. Zeit. fur Rub. Ind., 39, 766.

29. Am. Sug. Ind., XL, 176.

30. Arch., 1904, 321.

458

CHAPTER XXIII.

THE DETERMINATION OP REDUCING SUGARS.

Solutions of dextrose and other hexose sugars when boiled with an
alkaline solution of a cupric salt reduce the latter to the cuprous state in the
form of cuprous oxide. Approximately two molecules of dextrose reduce five
molecules of a cupric salt, but the quantities reduced vary with the conditions
of experiment. Tables connecting the amount of copper contained and the
amount of reducing sugar have been constructed by a number of experimenters.
The method of Allihn1 is that generally adopted, and is as follows — :*

Allihn's Method. — The solutions used are : —

A. 34-64 grms. copper sulphate in 500 c.c.

£. 173 grms. potassium sodium tartrate and 125 grms. caustic potash in
500 c.c.

Thirty c.c. of each solution are mixed, 60 cc. of water added, and the
whole brought to the boiling point over a direct flame ; twenty-five cc. of the
reducing sugar solution are then run in, the whole again brought to the boiling
point, and the boiling continued for two minutes ; an equal volume of cold
water is then added and the reduced copper determined by one or other of the
methods given below, whence the amount of reducing sugar is obtained from
reference to the tables in the Appendix.

The Filtration of the Cuprous Oxide.— A. If filtration over
reduced pressure is not available paper must be used ; the reduced copper oxide
passes very readily through paper, and only paper of close texture can be used.
The paper always absorbs and retains copper sulphate, and the amount must
be determined by a blank experiment.

B. The Soxhlet tube, Fig. 255, very often used, consists of a glass
tube about six inches long in all ; the upper portion is about three inches long
and half an inch in diameter, and terminates in a concave bottom to which is
attached a short capillary of about J% in. bore ; the lower half is about three
inches long and in diameter tapers from half to T3^ in. It is prepared for use

* Munson and Walker's method substitutes caustic soda for potash and a two for a four
minute boiling ; I give Allihn's method since it still remains official in the U.S. : it is moreover
used by Browne whose scheme is the only one completely accounting for all the factors in the
assay of complex sugar mixtures ; Browne's check analyses by Allihn's method leave nothing to
be desired on the grounds of accuracy. (N.D.)

459

CANE SUGAR.

FIG. 255.

thus: — A plug of glass wool is placed on the concave bottom of the tube

and above this a pad of asbestos ; the plug of glass wool should be about f in.

deep and the asbestos about T^ ; the best quality of asbestos must be used and

previous to use it should be digested, first in
caustic soda, then in nitric acid, and finally in
water. After the Soxhlet tube has been pre-
pared, it is fitted into the stopper of the filter
flask and filled about three parts full with water;
a small funnel is then fitted on to the tube, the
stem of which does not quite reach to the level
of the water in the tube ; the funnel is then
filled with water and the pump started ; as the
water passes through the filter, the liquid under-
going filtration is poured into the funnel, care
being taken to keep the funnel full; when
all the copper oxide has been brought into
the funnel; the level of liquid is maintained by

hot water until all the precipitate has passed into the Soxhlet tube and is

continued until the washing is complete.

C. A Grooch crucible consists of a tall crucible of conventional pattern,

the bottom of which is a perforated disc ; it is prepared for use as described

for the Soxhlet tube, save that the pad of glass wool is unnecessary.
The filtration apparatus used in the

laboratories of the Hawaiian Sugar Planters'

Association is shewn in Fig. 256 ; the filter

flask is of the form due to Diamond. The tube

a communicates with the vacuum pump ; con-
nection with the atmosphere may be made by

the cock on the tube I ; the Gooch crucible c

is held in the carbon tube d, a tight joint being

made by a piece of inner tubing of a bicycle

tyre ; the filtrate may be discharged through

e. The advantages of this apparatus for all

vacuum nitrations are obvious.

The Determination of the Re-
duced Copper. — A. As Cuprous Oxide.
The cuprous oxide after collection by one or
other of the above methods is dried to con-
stant weight, preferably in a vacuum oven, or else at 105°C. The drying is
materially accelerated by washing the precipitate first with alcohol and then
with ether.

B. As Cupric Oxide. — If the cuprous oxide has been collected on paper
the precipitate is, after drying, detached as completely as possible from the

460

FIG. 256

THE DETERMINATION OF REDUCING SUGARS.

paper and ignited in a porcelain crucible ; the paper and adhering cuprous
oxide are burnt separately, the cuprous oxide being partly reduced to copper ;
the ash and reduced copper are placed in the crucible, a few drops of nitric
acid 'added, evaporated to dryness and cautiously ignited. If collected in a
Soxhlet tube the narrow end of the tube is connected by rubber tubing to a
vacuum pump and a current of air is sucked through the layer of cuprous
oxide ; at the same time the tube is heated over a small flame ; the cuprous
oxide is seen to glow and is rapidly converted into cupric oxide. If a Gooch
crucible has been used, it and its contents are heated at a low red heat, care
being taken to prevent the reducing gases of the flame entering the crucible,
an end which is best obtained by placing the crucible containing the cuprous
oxide inside a second one.

C. — As Copper, by Reduction in Hydrogen. — The precipitate of cuprous
oxide conveniently collected in a Soxhlet tube is attached to an apparatus
generating hydrogen, and a current of hydrogen is passed through the tube.
On gently heating the tube the cuprous oxide is rapidly reduced to metallic
copper.

According to Perrault2 the hydrogen should be purified by being passed
through towers containing —

a. Crystals of iodine, mixed with pumice stone.

b. Caustic soda.

c. Potassium permanganate 5 per cent., in caustic soda of density 1*32.

d. Potassium bichromate in concentrated sulphuric acid.

D. — By Electrolytic Deposition. — In the United States
Agricultural Department's laboratory the copper is obtained
by electric deposition ; the cuprous oxide is dissolved in
nitric acid and collected in a platinum basin of about 175
c.c. capacity ; after the addition of 3-4 c.c. sulphuric acid the
copper is ready for deposition, which is thus effected by
Spencer.3

" Where a direct current is used in lighting the
sugar-house, it is the most convenient source of electricity
for depositing the copper. The current must be passed
through a resistance or regulator in addition to the lamp. A
convenient and durable regulator is shown in Fig. 257 ; c
is a glass tube partly filled with water slightly acidulated
with sulphuric acid ; the wire a connects with a platinum
sealed into the tube ; b s a glass tube through which a
copper wire extends and connects with a platinum wire
e sealed into this tube. The tube b may be slipped up and down, thus
regulating the distance between the wires e and a and regulating the current.
The twin wire m is separated, severed, and one end d connected with the
platinum dish in which the copper is to be deposited and the other with the

FIG. 257.

461

CANE SUGAR.

regulator b, thence through the acidulated water, and a with the platinum
cylinder suspended in the copper solution. Sufficient current for a large
number of dishes arranged in sets of four will pass through a 16 C.P. or 32
C.P. lamp. The copper should be deposited very slowly. Usually, if the
apparatus he connected when the lights are turned on in the evening, all
the copper will he deposited before they are turned off in the morning."

E. By the Permanganate Process.* — In this process the cuprous oxide is
dissolved in a concentrated solution of ferric sulphate in 25 per cent, sulphuric
acid ; the ferric oxide is reduced by the cuprous oxide under the equation

5 Cu2 0 + 5 Fe2 (S04)3 + 5 H2 S04 = 10 CuS04 + 10 Fe S04 + 5 H20
and the ferrous sulphate formed is estimated by titration with potassium per-
manganate.

The exact copper value of the permanganate should be determined by
direct assay against a pure preparation of a copper salt.

A solution of a ferric salt will always decolourize a few drops of deci-
normal permanganate, and hence a fixed quantity of the ferric solution should
be adhered to ; by standardizing the permanganate under the conditions of the
subsequent assays this source of error is automatically removed.

F. Sidersky's Process.5 — In Sidersky's method the precipitated cuprous
oxide is dissolved in a measured quantity of standardized sulphuric acid to which
a little potassium chlorate has been added. The reaction proceeds as follows : —

3 Cu2 0 + 6 H2 S04 + K Cl 03 - 6 Cu S04 + K Cl + 6 H2 0.
The excess of sulphuric acid is then titrated with standard alkali, or an
excess of standard alkali may be added and titrated back with standard
sulphuric acid ; in the presence of free ammonia the solution is blue changing
to green when all the ammonia is saturated. It is advised that half normal
ammonia be employed. The amphotere in this method appears to the writer's
eye inconveniently large, the change from blue to green not being at all sharp.
The ammonia and sulphuric acid solutions should be standardized against each
other, using 2 c.c. of a concentrated solution of copper sulphate as an indicator.

G. lodometric Process. — The reactions involved are

2 Cu(CH3COO)2 + 4 KI = Cul + 4 KCH3COO + I2
2 Na2S203 + I2 = 2 ]STaS203 -f 2 Nal

From the above equations it follows that 126*8 parts of iodine are equiva-
lent to 63 -5 parts of copper.

The precipitated cuprous oxide is dissolved in nitric acid, the excess of
acid partly removed by evaporation, neutralized with a slight excess of sodium
carbonate, and the precipitate redissolved with acetic acid. A slight excess of
potassium iodine over that indicated as necessary from the above equation is
added, and the iodine determined in the usual way with sodium thiosulphate,
using starch as an indicator.

The thiosulphate solution should be standardized against pure electrolytic
copper or a pure preparation of a copper salt.

462

THE DETERMINATION OF REDUCING SUGARS.

Reduction Process employing Prolonged Heating.—

There are not wanting objections to a boiling of the copper and glucose
solutions for a short period, and processes involving the keeping of the materials
for up to 15 minutes on a water bath have been proposed. These processes
have never been so generally adopted as have those entailing a boiling of short
period, and Munson and Walker7 in particular have shown that serious error
due to surface oxidation is thereby introduced.

Dextrose Ratio of Reducing Sugars. — The tables of Allihn
give the equivalence between copper and dextrose ; the methods described and
the tables are equally applicable to all reducing sugars, as Browne8 has shown
that the relative reducing powers of the different reducing sugars are constant.
The dextrose ratio of levulose is given by Browne as '915, i.e., where a certain
weight of dextrose reduces one part of copper, the same weight of levulose
will reduce '915 part of copper, hence if levulose is being determined, the
analysis is made exactly as if for dextrose, the final result being divided by
•915, so as to correct for the difference in the reducing powers of the sugars.

The reducing powers of some sugars compared with dextrose as unity are

Dextrose .. .. .. .; . .. .. I'OOO

Levulose . . . . . . . . . . . . .... '915

Xylose.. ., .. _.. ... -983

Arabinose .. ., .. .... 1.032

Invert Sugar . . . . . . . . . . . . . . -957

Galactose .. .. .. .. ..... .... '898

Lactose -678

Maltose .. .. • ... - .. .. .. -620

The Effect of Cane Sugar in the Determination of
Reducing Sugars. — Cane sugar has a slight reducing action on the copper
solution, and this action is proportional to the amount of cane sugar present,
and to the amount of copper left unreduced ; the error becomes very notice-
able when bodies such as raw cane sugars containing 96 per cent, cane sugar
and less than 1 per cent, reducing sugars are being analysed. This error is
thus corrected by Browne.8

" The grms. of sucrose in the 25 c.c. of solution to be analysed by Allihn's
method are divided by the mgrms. of dextrose found-f 40 ; the quotient will
give the required correction in grms. to be deducted."

For the determination of invert sugar in the presence of cane sugar the
methods of the Association of Official Agricultural Chemists, which are based
on those of Herzfeld and of Meissl and Hiller, enjoin the use of a copper
solution different from that of Allihn ; for the determination of dextrose alone
Allihn's copper solution is used; as the use of two solutions is inconvenient,
the writer only gives the method of Browne for the correction due to the
presence of cane sugar.

663

CANE SUGAR.

Necessity to adhere to the same Conditions. — The amount
of copper reduced by a weight of reducing sugar depends on the time of
boiling, the composition of the copper solution, the quantity used, and on the
concentration of the sugar solution ; and hence where accuracy is desired the
exact conditions under which the tables were constructed must be followed.

General Considerations of Gravimetric Processes.—

The amount of copper reduced forms the basis of the calculation of the
corresponding amount of reducing sugars ; provided only cuprous oxide were
precipitated, weighings as cuprous oxide, as cupric oxide, as metallic copper,
or determination of the copper by other methods would give equivalent results.
In actual practice, and especially when dealing with low grade products,
equivalence is not found. Zerban and Naquin9, with pure invert sugar,
invariably found that the weight of cuprous oxide was greater than should
correspond with the weight of cupric oxide found after complete oxidation of the
former. They found, in addition, that the weight of cupric oxide corresponded
very closely with that of the copper determined in the precipitate, and this
difference they attribute to the retention of water by the cuprous oxide.
With actual factory products they found that the weight of both the cuprous
and cupric oxide was greater than that which corresponded to the copper in
the precipitate, and they attribute this to the co-precipitation of mineral
matter weighed along with the precipitate. It follows, then, that the excess
copper methods, to be considered accurate, demand the determination of the
copper in the precipitate, which can be done electrolytically, by the perman-
ganate or by the iodometric processes already given. In the writer's opinion,
this last process combines both convenience and accuracy.

Direct Volumetric Methods. — In these methods a fixed quantity
of alkaline copper tartrate solution is titrated with the solution under analysis
until all the copper is reduced. The copper solution is usually known as
Fehling's solution, and is of composition

Copper sulphate, 34-64 grms. per 1000 c.c.

Caustic soda, 80 grms., and potassium sodium tartrate, 180 grms. per
1000 c.c.

Equal quantities of the above are mixed, and 20 c.c. of the mixed solution
are reduced by approximately '05 grm. glucose.

As this method is the one usually employed in tropical sugar factories by
unskilled workers, it is described in full detail, the remarks and directions
applying mutatis mutandis to the other volumetric processes given. The mixed
solution of copper sulphate and alkaline tartrate is known as Fehling's
solution ; this is a deep blue solution which on boiling with glucose throws
down a precipitate of red oxide of copper (cuprous oxide), the solution at the
same time becoming lighter and eventually colourless, provided that a pure

464

THE DETERMINATION OF REDUCING SUGARS.

solution of glucose be used. With cane juices, &c., the solution after precipi-
tation of all the copper is yellow in colour. Fehling's solution, as sold in the
shops, is twice as concentrated as the solution obtained by mixing equal bulks
of the copper sulphate and the alkaline tartrate solutions, and 10 c.c. of the
one or 20 c.c. of the other will be completely precipitated by approximately
•05 grm. of glucose. As Fehling's solution when mixed is apt to decompose,
it should be standardized before use, and even if its components are kept
separately it should still be standardized, as copper sulphate crystals are
difficult to obtain pure. The standardization is performed by titrating the
Fehling's solution with a solution of invert sugar of known composition until
all the copper is precipitated ; in subsequent analyses the conditions of the
standardization must be strictly adhered to. The manipulation of a deter-
mination, whether standardization or analysis, is as follows : —

10 c.c. of Fehling's solution as found in the druggists' shops or 20 c.c.
prepared as described above are placed in a small flask or large test tube and
about 50 c.c. of water added ; the exact quantity is immaterial so long as a
fixed measure is adhered to. The whole is brought to the boil and the glucose
solution added in quantities of 1 c.c. from a burette to the boiling Fehling's
solution until the addition of 1 c.c. causes the final discharge of the blue
colour. This preliminary experiment gives the amount of glucose solution
required to the nearest c.c. If the number of c.c. taken differs materially from
that of the solution used when standardizing, it should be diluted until of
approximately the same strength. A second portion of Fehling's solution is
now diluted and boiled and a quantity of glucose solution added, just a little
less than that which the preliminary experiment has shown necessary, and the
whole boiled for exactly two minutes ; the glucose solution is then added drop
by drop to the still boiling mixture until all the copper is reduced. Owing to
the yellow colour of cane juices, &c., in alkaline solution, the disappearance
of the blue colour is not sharp, and the critical point of the operation is deter-
mined as follows : — A solution of copper and potassium ferrocyanide in acetic
acid solution gives an intense brown colouration. A drop of the nearly com-
pletely reduced Fehling's solution is removed in a Wiley or Knorr filtering
tube and placed on a porcelain tile ; to this is added a drop of potassium
ferrocyanide solution and a drop of acetic acid : the presence of copper in
solution is shown by a red colouration. This test is made for every drop of
glucose solution added, after the blue colour has become indistinct.

Wiley's filter tube consists of a glass tube with a flange formed by
softening one end and pressing on a wooden block ; over this flange is tied a
piece of linen and an asbestos film is formed on this by suction. Knorr
modified this by sealing in the end of a glass tube a perforated platinum disc.
On placing one of the tubes in the turbid liquid and applying suction, a little
of the liquid is filtered through the asbestos free of copper oxide ; after using
each time the tube should be washed out.

465

30

CANE SUGAR.

The following method of filtration, is not inferior to the above : a number
of filters are folded from papers about 3 cm. in diameter; one of these is
grasped with the point of a small forceps and held in the material to be
tested ; a clear solution passes into the interior of the filter from which one
drop is removed with a pipette such as is used for filling fountain pens.
Ling and Eendle10 use an indicator prepared as follows : —
One grm. each of ferrous ammonium sulphate and ammonium sulpho-
cyanide are dissolved in 20 c.c. of water, to which is added 5 c.c. of hydrochloric
acid ; if necessary this is decolourized with a little zinc dust and the solution
preserved out of contact with air ; a cupric salt gives an intense red
colouration with this indicator ; the indicator becomes coloured after standing,
but may be decolourized several times by the addition of zinc dust, its
delicacy eventually becoming impaired.

Pavy's Method.11 — In Pavy's modi-
fication of Fehling's method, ammonia
is added with the object of keeping in
solution the cuprous oxide. The solu-
tion is prepared by adding to 120 c.c. of
Fehling's solution (10 c.c. = '05 grm.
glucose) 300 c.c. of ammonia -880, and
making up to 1 litre ; 50 c.c. of this
solution are reduced by -025 grm. of
glucose. The determination is made as
follows:— The apparatus (Fig. 258\
consists of a flask holding about 150 c.c ,
into the neck of which is fitted a rubber
stopper carrying three tubes, one of
which communicates with a reservoir of
ammonia by a rubber tube carrying a
screw clamp ; a second communicates
with a burette containing the glucose
solution, the flow of which is controlled with a screw clamp ; the third serves to-
carry away and condense under water the escaping fumes of ammonia. The
whole apparatus is supported by suitable holders ; 50 c.c. of Pavy's solution are
placed in the flask and boiled, ammonia being allowed to drip slowly into the
flask. As soon as the air is expelled, indicated by the almost complete absorp-
tion of the escaping bubbles, the glucose solution is slowly added and continued
until the blue colour is discharged ; the last few drops should be allowed to flow
very slowly. The addition of the ammonia must be continued throughout the
experiment, and as, notwithstanding the partial expulsion of the air on boiling,,
the reduced copper reoxidizes, the experiment should be made as expeditiously as is
compatible with accuracy. The above remarks in describing Fehling's method as-
regards standardization, conditions of experiment, &c., are equally applicable here.

FIG. 258.

466

THE DETERMINATION OF REDUCING SUGARS.

Peskds Method.™ — Peska's modification of Pavy's method consists in
covering the copper solution with a layer of pure paraffin and conducting the
experiment at a temperature of 80° C., the copper solution not heing allowed to
boil. The solution employed by him is 6-9 grms. pure copper sulphate and
160 c.c. of 25 per cent, ammonia in 500 c.c. mixed immediately before use with
an equal volume of 34*5 grms. Rochelle salt and 10 grms. of caustic soda, also
in 500 c.c. ; 100 c.c. of the mixed reagent are reduced by 80-2 mgrms. of
dextrose in 1 per cent, solution, or by 84-0 mgrms. of invert sugar in 1 per
cent, solution.

Soldaintfs Method.1'3 — This process is not generally used in estimating
reducing sugars, but is useful for the detection of small quantities of reducing
sugars, and of cane sugar after inversion. A formula for its preparation is —
copper sulphate, 3'464 grins. ; potassium bicarbonate, 297 grms. ; dissolve in
1000 c.c. ; equal volumes of this reagent and of the solution under inspection
are boiled ; in the presence of reducing sugars the cuprous oxide separates in
an intensely red condition ; as little as *005 grm. sugar per 100 c.c. may be
detected.

General Considerations of Volumetric Methods.— In the

volumetric assay of glucose the Fehling solution is standardized against a solu-
tion of dextrose, invert or other sugar of known composition ; the amount of
copper reduced is, however, influenced by the time of boiling, by the concen-
tration of the sugars, and by the simultaneous presence of cane sugar. The
first two factors are capable of control, but the latter is not ; the last factor is
of greatest influence when the cane sugar is in great excess, as happens in the
analysis of sugars ; the volumetric process then cannot lay claim to great
accuracy unless the Fehling solution be standardized by a preliminary assay
with cane sugar and reducing sugars in that proportion approximately in which
they occur in the materials under analysis.

Ling and Rendle,14 however, consider that the volumetric method, when
properly conducted, gives results equally accurate with the gravimetric method,
and at a considerable saving of time.

Preparation of Sugar Solutions for Reducing Sugar

Assay. — The material used for the assay of reducing sugar may be submitted
to the action of a clarifying agent or not, and very great differences in methods
of working obtain. Pellet has repeatedly protested against the use of basic
lead acetate, and it has been shown by Geerligs15 and himself that this material,
in the presence of chlorides, sulphates and other bodies carries down both
dextrose and levulose ; on the other hand, with the use of no clarifying agent,
bodies other than reducing sugars which act on the copper solution may be
present ; for this reason it is customary with many chemists to use neutral
acetate of lead as a clarifying agent. Zerban and Naquin9 have shown that
with cane molasses a little more copper is precipitated with unclarified solutions

467

CANE SUGAR.

than with solutions clarified with neutral acetate of lead, and the writer is of
the opinion that results closest to the truth are obtained with the use of this
material. In case clarification with a lead salt is used, the excess of lead
must he removed ; this may be done by the addition of a soluble sulphate,
carbonate or oxalate.

The International Commission for Uniform Methods of Sugar Analysis,
sitting in London in 1909, failed to agree on this point ; basic lead acetate
was forbidden, and neutral lead acetate was objected to by the English chemists
only, so that no agreement was reached.

With no treatment at all the gravimetric process is impracticable with low
grade products, owing to filtration being impossible ; clarification with alumina
cream will almost invariably overcome this difficulty.

Determination of Cane Sugar as Glucose.— On treatment
with acids cane sugar is quantitatively converted into equal parts of dextrose
and levulose, the mixture of the two being known as invert sugar; from
100 parts of cane sugar there are obtained 105*32 parts of invert sugar.

In most text books the scheme given is to determine the invert sugar in
the sample before inversion. Let the invert sugar be in a sugar, say, 2*0 per
cent. The sugar is then inverted and is now found to contain, say, 103*6 per
cent, sugar, calculated as invert sugar ; deducting the invert sugar there
remains 101-6 per cent, cane sugar as invert sugar, and this converted to cane
sugar by dividing by 1-0532, or by multiplying by -95, gives the invert sugar
as 96*52 per cent.

If this scheme is to be used as an accurate one it is essential that gravi-
metric processes be used to estimate the glucose, that the effect of the presence
of cane sugar in determining the glucose originally present be allowed for, and
that the correct factors connecting weight of copper be obtained. An example
of the method of calculation is appended.

Ten grms. raw sugar were dissolved in 100 c.c., and 25 c.c. (= *4 grm.
sugar) treated according to Allihn's process ; there were obtained 84-6 mgrms.
copper = 43-2 mgrms. dextrose, equivalent to 45*1 mgrms. as invert sugar;
hence the material contains approximately 1*13 per cent, reducing sugars as
invert sugar. 10 c.c. of the above solution were inverted, neutralized, and
made up to 200 c.c. 25 c.c. (= -125 grms. sugar) treated according to
Allihn's process gave 237-4 mgrms. copper rr 122-5 mgrms. dextrose = 127*7
mgrms. invert sugar, or 102*32 per cent, total sugar as invert sugar. Deduct-
ing the invert sugar already found as present before inversion, there is due to
the cane sugar 101*09 per cent, as invert sugar, which, converted to cane
sugar, gives 96*04 per cent, as the approximate amount of cane sugar.
Applying Browne's correction, t.*., dividing the grms. sucrose in the 25 c.c. of
solution to be analysed by Allihn's method by the mgrms. of dextrose found
+ 40, the calculation appears : Approximate amount of cane sugar in 25 c.c.

468

THE DETERMINATION OF REDUCING SUGARS.

of original solution -96 x '4 = -384 ; mgrms. dextrose + 40 = 83-2 ;
•384 -r- 83-2 = -0046 grm. ; i.e., 4'6 mgrms. dextrose are to be deducted
from the amount found, which now appears as 43-2 — 4'6 = 38-6 mgrms.
dextrose = 40*3 mgrms. invert sugar, or 1*07 per cent, as the correct amount
of reducing sugars calculated as invert sugars.

The invert sugar due to the cane sugar is then 102-32 — 1-07 = 101-25
per cent. = 96'18 per cent, as the true amount of cane sugar present.

Optical Assay of Levulose.16 — The rotation of levulose falls
rapidly with rise of temperature ; hence by observations of the optical activity
at different temperatures the amount of levulose can be estimated ; for each
1° C. rise in temperature and for 1 grm. levulose in 100 c.c., the rotation falls
•0357 Yentzke degree ; assuming the other sugars present are not affected, the
amount of levulose present follows directly.

Identification of Levulose.— Pierarts17 uses the folio wing solution:
per 1000 c.c. 12 grms. of glycocoll, 6 grms. freshly prepared cupric hydroxide,
50 grms. potassium carbonate ; in the cold this solution is reduced by levulose
alone and by no other sugars which occur in analysis.

Direct Assay of Dextrose in the Presence of other
Reducing Sugars.— Romijn's18 method is based on the observation that
dextrose and other aldose sugars readily oxidize iodine, levulose and ketose
sugars having a very small oxidizing action at low temperatures. The assay
is made as under. The iodine solution contains 40 grms. of borax and about
10 grms. of iodine per 1000 c.c. ; of this solution 25 c.c. are mixed with 25
c.c. of the solution under analysis which should contain about -15 grms. sugar ;
the mixed solutions are contained in a narrow necked flask with a long glass
stopper ; the flask and its contents are then placed in a thermostat for 16 — 22
hours ; the stopper is wired down and the gutter between the stopper and
neck of the flask is sealed with water. On removal from the thermostat the
contents of the flasks are acidified with hydrochloric acid and the excess of
iodine determined with thiosulphate. For 2 atoms of iodine I molecule of
glucose is calculated. The reaction involved is given on page 462.

Separation of Dextrose and Levulose from Sucrose.19 —

A.mmoniacal lead acetate prepared by adding ammonia to lead acetate until the
opalescence which forms just disappears precipitates dextrose and levulose
from solution ; the sucrose remains in solution as a soluble lead compound ; the
precipitated lead-sugar compounds are suspended in water through which is
passed a current of carbon dioxide ; the lead dextrose compound is decomposed
and is removed by filtration ; the lead levulose compound may then be decom-
posed by hydrogen sulphide ; this method was used by Winter in pioneer work
on the nature of the sugars of the cane, but is unsuited for ordinary laboratory
routine.

469

CANE SUGAR.

REFERENCES IN CHAPTER XXIII,

1. Zeit. filr Rill. Ind., 1889, 734.

2. Le Rhum p. 238.

3. Handbook for Beet Sugar Chemists, p.

4. Zeit. fur Anal. Chem., 12, 296.

o. Bull. Assoc., July, 1886; Sept., 1888.

6. After Sutton's Volumetric Analysis, p. 189.

7. J. A. C. S., 24, 1082.

8. J. A. C. S., 28, 4.
-9. /. 8. </., 115.

10. Analyst, 30, 182.

11. Chem. News, 39, 77.

12. Chem. News, 71, 235.

13. Zeit. filr Rub. Ind., 1889, 933.

14. Analyst, 33, 160,

15. /. S. J., 117.

16. Wiley, Agric. Anal, Vol. III., 267.

17. Bull. Assoc., 25,, 830.

18. Zeit. Anal. Chem., 36, 349.

19. Wiley, Agric. Anal., III., 283.

470

\

X

CHAPTER XX1Y.

THE ASSAY OF SUGAR HOUSE PRODUCTS.

Determination of Water and Total Solids.— l. By Specific
Gravity. — The connection between specific gravity and percentage of sugar in
solution has been very accurately worked out, and hence if the specific gravity
of a pure sugar solution be known the percentage of sugar is obtained by
reference to tables ; in actual sugar house work it is customary
to treat all bodies present in solution as having the same effect on
the density as has cane sugar; thus a juice of density 1-06566 is
of the same density as a 16 per cent, solution of sugar, and this
juice is conventionally returned as containing 16 per cent, apparent
total solids. This determination is usually made by taking the
density with a Erix hydrometer ; this instrument is graduated on
a sugar basis; that is to say, 16° Brix is indicated when the
hydrometer is immersed in a 1 6 per cent, solution of
sugar. The hydrometer consists of a glass instrument
of the shape shown in Fig. 259 ; on the hydrometer
being immersed in a liquid it will sink to a certain
point, dependent on the density of the liquid ; the
point where the level of the liquid cuts the stem of
the hydrometer gives on the scale the density of the
liquid.

Owing to capillary attraction the liquid will rise
as much as one-eighth of an inch up the stem of the
hydrometer, Fig. 260 ; it is at the lower level that the
reading is to be taken.

Westphal Balance. — The Westphal balance may
also be used to obtain the specific gravity and
apparent total solids of a sugar solution, as also may the pycno-
meter ; these methods find no extended use in a sugar laboratory.
As the determination of total solids from density is itself only
approximate, there is no benefit obtained by a determination of
the specific gravity to an extra decimal, and a determination
by the hydrometer is in nearly every case of sufficient delicacy.

Standards of Reference.— The table connecting sucrose per
cent. (Brix0) and density usually found are referred to water at
IG' 9' 1 7 -5° C. as unity ; the hydrometers in use are graduated either at
17'5° C. or else for use in the tropics at 27*5° C.; let a Brix spindle correct at
17-5° C. indicate 20° at 28° C. ; then from the table of corrections in the

471

CANE SUGAR.

Appendix the true Brix is 20-72° and the specific gravity at 17-5° compared
with water at 17'5° C. is 1 '08652 as obtained by interpolation from the Brix
table given in the Appendix ; at the same time the specific gravity at 28° C.
compared with water at 17-5° C. is that corresponding to 20° Brix or 1-08329 ;
if the spindle is graduated at 27-5° C. and at this temperature reads 20°, the
true Brix is 20 and the specific gravity at 17-5° C. compared with water at the
same temperature is 1*08329 ; from the table of corrections a spindle graduated
at 17-5° C. in place of reading 20° Brix would read (20 — -68) = 19-33° B.
and the specific gravity at 27-5° C. compared with water at 17*5° C. is then
1-08026. Nearly all chemists are agreed that readings should be taken at (or
referred to) 20° C. and compared with water at 4° C. as standard. In the
Appendix a Brix table on this basis is also given ; whilst grudging the space
occupied by the necessity of giving two tables, the present confusion of systems
makes it obligatory. Any Beaume table is purposely omitted as this irrational
scale can disappear none too soon.

2. By Drying to Constant Weight.
This method described below gives
the true total solids and true water,
and should be used in all analyses
except when a rapid * test,' as in the
control of crystallization in motion
processes, is required.

Sugar solutions on partial drying
form a viscous mass from which the
last parts of water are very slowly

FIG. 261.

expelled under atmospheric pressure,
and at the temperature of boiling
water. As elevation of the temperature leads to decomposition of the organic
matter, sugar solutions should be dried in vacuo, and at the same time as large
a surface as possible should be exposed ; this latter end is obtained by pouring
the sugar solution over some such material as clean dry sand, pumice stone, or
filter paper crimped into a wad. The routine of an analysis is as follows: — Into
a flat dish of suitable size is placed a sufficient quantity of the absorbent
material and the dish and its contents dried to constant weight ; from 5 c.c. to
10 c.c. of the material under analysis is then run into the dish, which is then
weighed a second time ; the dish is then dried to constant weight.

In actual sugar house work it will be found very convenient to prepare in
advance a large number of dishes containing sand, the sand being adjusted so
that all the dishes are of uniform weight, and these are kept ready for use in a
specially constructed dessicator of large size ; as recommended by Spencer the
lead capsules used as coverings for bottles are very convenient and cheap. The
vacuum oven, used by the writer, which is capable of construction with planta-
tion labour, is shown in Fig. 261. It consists of a piece of six-inch copper

472

THE ASSAY OF SUGAR HOUSE PRODUCTS.

piping about nine inches long ; round this is constructed a steam chamber, b,
into which exhaust steam from any convenient source is led through the pipe
a ; a pipe, c, carries away the condensed water ; the interior of the oven is
connected to the last vessel of the evaporator by a half inch pipe, d.
One end of the oven is permanently closed, the other end being kept closed
when in use by a metal disc, A, on which is fitted a washer of soft material. The
external pressure of the atmosphere secures a tight joint, and thumb screws
are quite unnecessary ; in an oven of this diameter two shelves can be fitted,
leaving room for the insertion of trays not more than half an inch high. The
pipe g serves to break the vacuum and it may, if desired, be connected to a
vacuum filtering apparatus. A thermometer and vacuum gauge are shown
at e and/.

FIG. 262.

This type of oven may be obtained from dealers in apparatus, and is
essentially similar to that originally described by Carr1 ; the use of sand is due
to Wiley and Broadbent2, and filter paper as an absorbent material was
suggested by Josse3.

3. From the Refractive Index. — It was shown originally by Main, whose
results were completely confirmed by Geerligs4, that the refractive index of
sugar house products is in direct proportion to the true total solids, and that this
relation obtains for all products from juice to waste molasses. The instrument
most convenient for this purpose is the Abbe refractometer, Fig. 262, with

473

CANE SUGAR.

beatable prisms, as made by the firm of Zeiss, of Jena. Tbe determination of
tbe refractive index is made as follows : — The instrument is brought into a
horizontal position, and the two prisms A and B separated by opening the
milled head clamp ai p ; a drop of the material under analysis is placed on one
of the prisms, which are then closed and secured by the clamp so as to obtain
a film of material ; the mirror R is then adjusted so as to throw a beam of
light through the prisms; looking through the observation telescope at 0 and
moving the alidade S on the left of the instrument, a dark shadow is seen to
move over the field. The reference point is the coincidence of the edge of the
shadow with the intersection of cross lines in the field of vision ; the reading
on the quadrant scale J gives directly the refractive index of the material
under examination, whence can be obtained the percentage of dry matter from
reference to the tables, given in the Appendix.

To maintain a constant temperature a stream of water should be allowed
to pass through the coil D E, arranged in the instrument.

The milled head M on the right of the base of the observation telescope
serves to correct for colour ; when not adjusted, instead of a uniform dark
shadow a coloured shadow appears, the dark shadow being obtained by rotation
of the milled head.

In the Appendix is given a table connecting refractive index and per cent.
of solids as arranged by Peck from Geerligs' data.

Determination of Ash. — The determination of the ash of sugar
products offers no difficulties ; the incineration is best performed in a platinum
dish at a low red heat to prevent any volatilization of potash ; as the sugary
materials swell greatly on heating, the dish used must be capacious and the
heating gradual.

It has been the custom with sugar analysts to determine the ash after a
preliminary carbonization with sulphuric acid, and to correct for the increase
in weight by deducting 10 per cent, from the recorded weight. This process
is of course inaccurate, and, so far as regards the sugar materials the writer
has encountered, unnecessary ; the preliminary carbonization is claimed to
render the materials more readily combustible.

Determination of Cane Sugar. — 1. In the Absence of Reducing
Sugars. — Weigh out a definite weight of material in a suitable vessel, such as
the German silver vessels sold by dealers for this purpose ; transfer to a flask
graduated at 50 c.c. or 100 c.o., and clarify by one of the methods given in
Chapter XXII. ; make up to the mark, filter and take the polariscope reading ;
then if the material be dissolved in 100 c.c , and if the 20 cm. tube be used

the percentage of sugar is given by the expression — =- where R is the

observed reading, N is the normal weight of the polariscope used, and W is
the weight of the material used.

474

THE ASSAY OF SUGAR HOUSE PRODUCTS.

If the liquid is already in the liquid form, the above procedure may be
followed, or 100 c.c. of the material may be taken, and after clarification by
one or other of the methods given, made up to 110 c.c., filtered and the
polariscope reading of the filtrate taken ; then the percentage of sugar is given

1*1 -
by the expression — - - — where D is the specific gravity of the material.

2. In the Presence of Reducing Sugars. — The sugar is obtained by the
Clerget process described in Chapter XXII.

The following are irregularities in the method of analysis which are
discussed under separate captions, and for which correction should be made : —

1 . Volume of precipitate formed on clarification.

2. Temperature of observation.

3. Concentration of solution.

4. Change in the specific rotation of the sugars before and after inversion.
The estimation of cane sugar as glucose is given in Chapter XXIII.

Determination of Fibre.* — In routine analysis fibre means that
part of the cane insoluble in water, and corresponds to the ' marc ' of the beet
industry ; the fibre is determined by removing the soluble constituents by
digestion with water or alcohol, and drying the residue to constant weight.

Pellet5 has shown that extractions with alcohol in a Soxhlet apparatus
give too high results, due to the precipitation by alcohol of bodies soluble in
water, and also that all bodies soluble in cold water should be first removed to
prevent a precipitation of albumenoids by hot water.

Analysis of the Cane. — The determination of the sugar in the
cane may be made by an inferential approximate method, or by more complete
methods.

Inferential Method. — Pass the cane under analysis through a hand mill,
collect and polarize the expressed juice ; then the per cent, of sugar in the cane
is given by the expression (100 — /) $, where/ is the percent, of fibre in the
cane, and 8 is the per cent, of sugar in the expressed juice. This method is
open to the following sources of error : — The juice of the cane is not uniform,
the first expressed juice being sweeter than that obtained later. The fibre,
too, is a very variable quantity, and unless the fibre be actually determined a
large error may be introduced. In Java it was once customary to estimate the
sugar percentage of the cane as '85 that of the sugar percentage of the first
mill juice, but this factor is very dependent on variety.

Complete Methods. — 1. Pass strips of the cane through a hand mill;
collect the expressed juice and crushed strips and weigh the latter at once ;
take as the weight of juice expressed the difference between the weight of
cane used and the weight of crushed strips or megass ; determine the sugar

* See Note in Appendix,
475

CANE SUGAR.

percentage of the expressed juice, and thus the weight of sugar in the juice;
determine separately the sugar percentage of the megass as given below, and
thence the weight of sugar in the megass. The sum of these determinations is
the weight of sugar in the weight of cane used.

2. After Spencer*. — Spencer very properly remarks that it is impossible
to satisfactorily comminute the cane without a special apparatus ; he recom-
mends for use the ' Hyatt ' cane reducer Fig. 263 ; this consists of a series of
circular staggered saws revolving at a high rate against which the cane is
forced, the comminuted cane falling into a covered box ; after obtaining the
finely divided sample 100 grms. are placed in a suitable vessel and boiled for
ten minutes with 100 c.c. of water; as much of the extract as possible is
drained off and the operation repeated seven times, the woody residue being

/// vy

FIG. 263.

finally pressed in a hydraulic or other powerful press ; after all the extracts
are united and made up to definite volume, the united extract is analysed.

3. A fine sample of the cane is obtained as above and the sugar extracted
in a Soxhlet apparatus, the extract made up to definite volume and its per-
centage of sugar determined ; this is the process preferred by the writer.

4. Zammaron's Method.1 — One hundred grms. of finely divided material
are placed in a wire basket, and the basket and its contents placed in a copper
vessel, at the bottom of which is a cock ; .200 c.c. of water are placed in the
vessel and boiled for ten to fifteen minutes ; the extract is then drawn off by the
cock and received in a litre flask ; this process is repeated seven times, when
about 960 c.c. of extract will have been obtained; basic lead acetate is then
added to the extract in the litre flask, and its contents completed to 1000 c.c.,
and polarized after filtration.

In the writer's experience with finely divided cane there is no necessity
for a prolonged boiling ; of appliances for dividing the cane the Hyatt cane
reducer and a ' jerked beef slicer ' give very fine samples ; the ' sausage
chopper ' often used does not give so fine a division.

476

THE ASSAY OF SUGAR HOUSE PRODUCTS.

Glucose is determined in the extract obtained as above.

Ash is obtained by incinerating at a low red heat a portion of the finely-
divided cane.

Water is determined by drying to constant weight, preferably in vacuo.

Fibre is determined by repeatedly exhausting with water the megass
obtained in sugar method 1, or the finely divided cane, and drying the
exhausted residue to constant weight.

When analysing cane or canes, it is of essential importance to remember
that the cane is not of uniform composition, and a sample must represent the
whole length of the cane. When making systematic control analyses of cane,
the writer has pursued the following method : — A factory was grinding sixteen
car-loads per hour ; from every car-load one cane was selected ; when sixteen
canes were thus obtained, the top sixteenth was cut from the first, the second
sixteenth from the second, and so on ; each piece of cane was then split
longitudinally with a sharp knife, first into halves, then one half into quarters,
and finally into eighths ; from the sixteen canes a sample weighing on an
average 200 — 300 grms. was obtained representing each portion of the cane.
Proceeding systematically on these lines, as many as 100 canes can easily be
analysed in a day of eight hours.

Analysis of Megass. — Water. — The determination of water in
megass so as to obtain figures representative of the working of the mills is a
problem which is not so easily solved as at first sight appears. The chief
difficulty lies in obtaining a sample of a bulk convenient for analysis and at the
same time representative of the many tons of megass made in a day. In the
writer's experience the very smallest sample for the actual analysis that can be
obtained is one of about 50 grms. weight, obtained as a sub-sample from one
of several kilograms taken across the whole width of the rollers. Megass is a
material which is exceptionally retentive of moisture, and when dried under
atmospheric pressure at the temperature of boiling water is completely dried
only after heating for long periods. The time taken for drying depends very
largely on the way the material is arranged in the oven ; the drying is quicker
the greater the surface exposed. The writer has found shallow tin trays about
4-5 inches square and half an inch deep very suitable. Such trays easily hold
50 grms. of megass, exposing a large area ; gauze baskets or linen bags do not
give such good results as regards time occupied in drying. When the drying
is carried out at atmospheric pressure, a temperature in the oven of 240° F. is
necessary if the megass is to be dried within a reasonable time ; megass placed
in a layer in a shallow tray will be completely dried in from four to six hours
at this temperature. Wherever possible, however, the vacuum oven already
described should be used. Spencer6 recommends that the samples taken for
determination of moisture should be about 500 grms., and that it be contained
in bags made of mosquito netting.

477

CANE SUGAR.

Sugar. — The process given in " Sugar and the Sugar Cane," and which is
essentially the same as that given by Geerligs,8 prescribed a diffusion in boiling
water for fifteen minutes, about 50 grms. of megass and 250 c.c. of water
being used. Following on the experiments of Pellet9, this process is not
sufficient to extract all the sugar, and he recommends the use of Zammaron's
process.

Geerligs10 has confirmed Pellet's observations on the analysis of megass
in so far that he found a higher polarization of the extract on repeated boilings ;
extraction in a Soxhlet apparatus with alcohol was, however, found to give
results agreeable with a fifteen minutes' boiling. The higher results found on
a longer boiling he attributes to a gradual solution of hemicelluloses, and
comes to the conclusion that the fifteen minutes' boiling gives accurate results.

N orris12 was unable to find any evidence of the solution of hemicelluloses
on prolonged boiling, and with finely divided megass recommends a digestion
of one hour as sufficient to extract all the sugar. In case a single extraction

is made, the results are calculated as under —

Grms.

Weight of megass . . . . . . 50

Weight basin, fibre and extract 459

Weight basin 212

Weight of extract and fibre 247

Allowing the megass to contain 45 per cent, fibre, the weight of the fibre
is 22-5 grms.; then the weight of the extract is 224'5 grms. Then if the
extract polarizes 3'0 the percentage of sugar in the megass is

30 X 26 X 247 X 100

50
the density of the extract being taken as unity without sensible error.

Davoll11 suggests with good reason the necessity of making two determi-
nations of water in megass ; one on the fresh sample and one on that after
preparation for sugar assay, results being calculated back to original moisture.

Glucose is determined in the extract obtained as above.
Fibre is obtained as described for fibre in cane.

It is customary in many sugar houses to determine the fibre in megass as
under. An analysis gave the following results : — water, 48-50 per cent. ;
sugar, 4'82 per cent. ; purity of last mill juice, 78*62; then solids in solution

4-82 X 100

in megass = — — — — = 6-13 and fibre in megass = 100 — 48-50— 6-13 =
lo'bZ

45 37 per cent. A possible error is introduced here by the acceptance of
the purity of the last mill juice as being the same as that of the residual juice
in the megass ; to determine this quantity the writer proceeds as follows : —
about 20 grms. of megass are completely extracted in a Soxhlet apparatus, the
extract evaporated to a volume of 50 c.c. and the total solids in the extract

478

THE ASSAY OF SUGAR HOUSE PRODUCTS.

determined by the refractometer ; the percentage of fibre is then the quantity
100 — per cent, water — per cent, total solids. This calculation and method
is of course applicable to cane also.

Analysis of the Juice. — The general methods for determination of
density, degree Brix, total solids, have been already given in this Chapter ; the
actual routine of the determinations is here described.

Degree Brix. — The actual practice of taking the degree Brix or total
solids is as follows : — If juice from the mill bed is being analysed, the sample
is poured into a cylinder about twelve inches high by three inches diameter ;
this cylinder is provided at the bottom with a tubulure, in which is fitted a

perforated cork carrying a bent
piece of glass tubing, which may
be closed by a piece of india-
rubber tubing and a clip; such
cylinders with draw-off cocks
ground in may be obtained at a
small price from dealers in ap-
paratus. The sample is allowed
to stand for about five minutes,
when the air bubbles will have
risen to the surface and the dirt
have sunk to the bottom ; a clear
negotiable sample can then be
drawn off into a second cylinder,
the hydrometer inserted, allowed
to come to rest and the degree
Brix noted ; the temperature is
taken at the moment of obser-
vation ; for each degree Pahren-
heit above or below that at which
the hydrometer is graduated -035

of a degree Brix should be added or subtracted. The preservation of samples
for analysis is referred to in Chapter XXIV.

The apparatus for taking the density of the juices may conveniently be
arranged as shown in Fig. 263 ; it is a shallow tray two feet square, lined with
lead, from which leads a pipe to carry off waste ; a tap for a water supply is
arranged over the tray, by means of which a current of water is always
available for cleaning apparatus and for cooling hot juices. Over the tray is
placed a shelf in which are pierced a number of holes by means of which
apparatus may be hung downwards to drain ; the shelf also serves as a stand
for cylinders in which the juice is settled. By the use of an arrangement like

479

CANE SUGAR.

this, the density determinations and sampling can be done without spilling
juice about the laboratory, and the whole apparatus easily kept sweet and
clean.

Purity. — The purity of a sugar product is the percentage of sugar on
total solids ; when the total solids are estimated from the density or degree
Brix, the term apparent purity is used as distinguished from true purity when
the total solids are determined by drying.

Sugar. — The determination of the sugar in the juice is carried out in
actual practice as follows: — A flask with two graduation marks, one at
100 c.c. and the other at 110 c.c., is filled to the 100 c.c. mark with
the sample of juice under analysis ; 6 or 7 c.c. of a solution of basic lead
acetate of density 1*25 are then added and the whole made up to 110 c.c. by
the addition of water. The flask and contents are then violently shaken and
filtered through a dry filter into a narrow cylinder ; those sold by dealers as
hydrometer immersion tubes, about six inches in height and one inch in
diameter, serve admirably ; the funnel which holds the filter paper may con-
veniently be stemless and rest on the rim of the receiving glass so as to prevent
evaporation. After sufficient of the juice has been filtered, a 20 cm. polaris-
cope tube is filled with the filtrate which must be perfectly clear and bright,
the polariscope tube closed, placed in the trough of the polariscope and the
reading observed. If JVbe the normal weight for the polariscope and R be the

l * l
reading, the sugar in the juice as grms. per 100 c.c. is --- — — — ; the pounds

per gallon, as it is general to express results in many English factories, are
one-tenth of this result ; the percentage of sugar is obtained by dividing the
grms. per 100 c.c. by the specific gravity. This routine can, of course, be
varied ; the normal weight of cane juice may be weighed out, a sufficiency
of lead acetate added, the whole made up to 100 c.c., filtered and polarized;
the reading in the polariscope will now give directly the percentage of sugar
in the juice. Spencer's pipette is a convenient instrument for obtaining the
normal weight of a cane juice without the use of the balance; the upper stem
of an ordinary pipette is graduated with numbers corresponding to tenths of a
degree Brix ; when the pipette is filled to one of these marks the weight of
liquid delivered is a multiple of the normal weight for juice of that particular
degree Brix; for polariscopes which have a normal weight of 26-048 grms.
these pipettes deliver twice, and for those whose normal weight is 16-19 grms.
three times, the normal weight of juice. The polariscope reading (after making
up to 100 c.c.) divided by two or three, as the case may be, gives the percent-
age of sugar in the juice.

Determination of Nitrogenous Bodies.— The determination
of the nitrogenous bodies in cane juice is chiefly of interest to the agricul-
tural side of a sugar estate ; it forms, however, a means of testing the

480

THE ASSAY OF SUGAR HOUSE PRODUCTS.

efficiency of any new methods of clarification. Perhaps the most con-
venient process is Gunning's modification of the original Kjeldahl moist
combustion process. In this process the material under analysis is heated with
a mixture of sulphuric acid and potassium sulphate, until the solution has
become colourless or of a pale straw colour. As applied to cane juice the
process may be thus conducted : 20 c.c. of juice are evaporated to small bulk
and washed into a 300 c.c. hard glass flask with 20 c.c. of concentrated
sulphuric acid ; add, in small quantities at a time, lOgrms. powdered potassium
sulphate ; heat very gently over a small flame till frothing stops, and then
raise the temperature and allow to boil till the contents of the flask are colour-
less ; transfer to a hard glass litre flask, add caustic soda to distinct alkalinity
and distil until all the ammonia is given off, collecting the distillate in 50 c.c.
of decinormal acid ; determine the excess of acid remaining by titration with
decinormal alkali ; bumping nearly always occurs near the end of the
distillation, and to prevent this, the latter operation may be carried out by a
current of steam, the flask itself being gently heated by a small flame. The
caustic soda should be introduced through a stoppered thistle funnel and the
distillation flask provided with a safety bulb to prevent any of the contents of
the flask being carried over mechanically. The sulphuric acid used should be
tested by means of a blank experiment for nitrogen and the quantity found
deducted from subsequent determinations.

Determination Of Amides13. — The material is boiled for one hour
with a 5 per cent, solution of sulphuric or hydrochloric acid, at the end of
which time the amide nitrogen is converted into ammonium salts ; after exact
neutralization with sodium carbonate the material is distilled over magnesia
free of carbonates, and the distillate is collected in standard acid and the
ammonia evolved determined in the usual way. Half the nitrogen of the
amide bodies is thus obtained as ammonia ; it is customary to calculate the
ammonia thus obtained to asparagin C4H8N203 ; if ammonia salts are present
these are determined separately.

Determination of Albumenoid Nitrogen13. —Place -7 grm.
of the substance in a beaker, add 100 c.c. of water, and heat to boiling; add
a quantity of Stutzer's reagent containing about '5 grm. copper hydroxide,
filter when cold, wash with cold water, and determine the nitrogen in the
precipitate.

Stutzer's reagent is thus prepared: dissolve 100 grms, copper sulphate
in 5 litres of water, add 2'5 c.c. glycerol, and then a dilute solution of sodium
hydroxide until the solution is just alkaline ; filter, rub the precipitate up
with water containing 5 c.c. of glycerol per litre, and wash by decantation on
filtration until the washings are no longer alkaline. Rub the precipitate up
again in a mortar with water containing 10 percent, of glycerol, thus preparing

481

31

CAN?; SUGAR.

a uniform gelatinous mass that can be measured with a pipette. Determine
the amount of copper hydroxide per c.c. of this mixture.

Determination of Gums. — By gums are meant those bodies
insoluble in alcohol ; 100 c.c. of juice are concentrated to a volume of about
20 c.c., and poured into 100 c.c. of 90 per cent, alcohol containing 1 c.c.
hydrochloric acid. The precipitate is allowed to settle and washed by decan-
tation with strong alcohol, collected on a tared filter paper or better in a
Gooch crucible, and dried to constant weight. The increase in weight gives
gums and ash ; the weight of ash is determined, and being deducted from the
weight of gum and ash gives the weight of gum.

Acidity and Alkalinity.— 1. 100 c.c. of the juice are titrated
from a burette with decinorrnal alkali ; to the juice a few drops of phenol -
phthalein solution are added, the neutralization of the excess of acid being
shown by the appearance of a pink colouration. The juice may be conveniently
contained in a white porcelain basin. In this method the juice is alkaline to
litmus before the appearance of the pink colour.

2. To 50 c.c. of the juice an excess of alkali is added and the volume
completed to 100 c.c. To successive further quantities of 50 c.c. varying
quantities of decinormal alkali are added and the volume completed to 100 c.c.
The minimum quantity of alkali that gives a juice of the same tint as that
to which an excess of alkali was added is a measure of the acidity of the
juice. The tint may be observed in small test tubes of about half-an-inch
diameter.

The point of exact neutrality in cane juice is hard to determine, the
change not being sharp, but a dirty olive-green colour obtaining over as many
as 4 to 5 c.c. of decinormal alkali ; and when indicators are used the change is
masked by the colour of the juice.

Carbonated Juices. — The carbonation process, which is but sparingly
used in cane sugar factories, requires special methods for its control ; an
abstract of the methods employed in beet sugar factories may be given here.

It is customary to determine the alkalinity of the juice of the first and
second saturation in terms of lime as CaO ; as this determination has to be
done rapidly, special methods of moderate accuracy are employed. One of
the simplest and most convenient is Yivien's. A standard acid containing
•875 gnn. H2S04 per 1000 c.c. is prepared; the acid is standardized against
decinormal alkali; 10 c.c. of the latter are equivalent to 56 c.c. of the acid
which, when exactly made up, neutralizes volume for volume a solution
containing -05 grm. lime per 1000 c.c. ; the indicator employed is phenolph-
thalein, which is placed in the stock of standard acid. The tube, Fig. 264,
is filled to the zero mark, and the standard acid added; as long as lime is-

482

THE ASSAY OF SUGAR HOUSE PRODUCTS.

in excess the juice remains red, becoming finally colourless when the lime is
neutralized. Each ten divisions in the tube correspond to •! grm. lime per
1000 c.c. For juice of the second saturation a weaker acid only one-fifth
the strength of the above is used.

The determination of the total lime in the juice is performed by the
usual methods; 100 c.c. juice are heated to boiling, ammonia added in
excess and filtered if necessary ; the lime is precipitated by ammonium
oxalate from the hot solution, boiled for two hours, filtered, washed, dried,
and weighed as carbonate or sulphate.

A

The alkalinity of a juice is in part due to caustic soda and
potash set free by the action of lime on the salts of the former
present in the juice ; when it is wished to determine the alkalinity
due to lime and to soda and potash, Pellet's method may be used,
1 . Determine the total alkalinity by titration with sulphuric acidr
using litmus as an indicator and making the titration at the boiling
point. 2. To a volume of the juice add an equal bulk of alcohol
which will precipitate the lime as an insoluble saccharate ; filter,
and in an integral part of the filtrate determine the alkalinity ;
the latter is due to free caustic potash and soda but is expressed
as lime for purposes of convenience ; by determining the total
lime, the combined lime can be likewise obtained.

Analysis of Massecuites and Molasses.— The

FIG. 264. sugar, glucose, ash, alkalinity, gums, moisture, &c., are determined
by the general methods already given.

Density. — The density of a massecuite has a two-fold meaning : firstly,
the apparent density of the material as it actually exists, a figure required to
calculate the weight of the factory product from its cubage, and secondly the
true density required in the control of the boiling.

The method used by the writer is as below : —
A large wide-mouthed vessel of the slope shown in Fig. 265 is
constructed of copper or brass, or even a wide-mouthed bottle may
be employed, if the mouth of the vessel is formed sloping inwards
and a stopper is ground accurately to fit this mouth ; through the
centre of the stopper is bored a hole about £in. in diameter.
Massecuite from the pan is allowed to flow into the vessel until
about seven-eighths full ; the vessel is then allowed to cool until
it has reached the temperature at which the factory measurements
of massecuite are taken, and the weight of massecuite determined. Water is
then carefully poured over the surface of the massecuite till the vessel is full,
the stopper inserted, when the excess of water escapes through the aperture
and is wiped off. The method of calculation is shown below : —

FIG. 265

483

CANE SUGAK.

Grins.

Weight of vessel and stopper empty ..... ._-?*'. 41 6 '35

,, ,, ,, and water ........ 2163-40

,, water ............... 1747*05

,, vessel, stopper, and massecuite ...... 2645 '95

massecuite ......... ..' .. 2229-60

,, vessel, stopper, massecuite, and water .. 2875*95

,, water above massecuite ....... 230

,, water in space occupied by massecuite . . 151 7 '05

2229-60
Apparent specific gravity of massecuite ...... « 517-0" ~ 1*^69

In using this method no attempt is made to remove imprisoned air-bubbles,
the object of the determination being to facsimilize the actual working of the
factory.

An accurate determination of actual specific gravity of a massecuite can
be made by this method, using instead of water an indifferent material such
as oil. This is introduced into a wide-mouthed vessel similar to the one
already described ; an oil of already determined density is poured over it, and
the two mixed until air-bubbles are no longer seen to rise. The stirrer may
conveniently be a piece of iron rod, of such a length that it may remain in the
vessel without interfering with the insertion of the stopper. After removal of
the air-bubbles the vessel is filled up with oil and the determination completed
as above. An example follows: —

Grins.

Weight of vessel, stopper and stirrer ........ 453*75

,, and oil ...... 1838'35

Specific gravity of oil (water 1-0) .......... -8550

Weight of oil .................... 1384-95

,, vessel, stopper, stirrer and massecuite . . 2548*35

,, massecuite ............... 2095*65

,, vessel, &c., massecuite and oil ...... 2743*20

,, oil above massecuite ........... 194*85

,, oil in space occupied by massecuite . . 1190' 10

2095-65
Real specific gravity of massecuite X '855=: 1*5056

In technical control the density of a massecuite or molasses is often
determined by dilution and taking the degree Brix of the diluted material.
An example will make the method clear ; 250 grms. of a massecuite dissolved
in water and made up to 1000 c.c. stand at 20*8° Erix; the total solids present
in the 1000 c.c. and also in the 250 grms. of material used are then -208 X
1077-4 =. 224*1 ; whence the percentage of solids or degree Brix of the masse-
cuite is 89*64, corresponding to a density of 1*491. The water per cent, in
the massecuite is, of course, the difference between 100 and the total solids —
in this case, 10*36 per cent.

484

THE ASSAY OF SUGAR HOUSE PRODUCTS.

Crystallized and Dissolved Sugar.— The total sugar in a
massecuite or molasses exists in two forms, either separated out as crystals, or
still remaining in solution in the necessarily accompanying water; in
general two similar juices, similarly treated and boiled to the same water
content, will separate out the same amount of crystals, but the actual
recovery at the centrifugals may be widely different. For in one case, by
skilful pan-boiling, the crystallized sugar is obtained in a form permitting of
easy separation from the molasses, and in a second, the presence of fine
crystals may cause considerable losses. The determination of the crystallized
sugar affords a valuable check on the pan-boiler.

Vivien's M#thodu. — Weigh out about 200 grms. of masse-
cuite and place in the funnel of the pressure filtering apparatus,
as in Fig. 266, connect the apparatus to a filter pump, and
wash with a cold saturated solution of pure sugar and water
until all molasses are removed ; transfer the crystals to a tared
dish and obtain their weight. Remove about 10 grms. and
dry to constant weight to determine the water adhering to the
crystals. At a temperature of 84° F., for each one part of
water 2*125 parts of sugar are dissolved in a saturated solution.
This last determination gives data to calculate the weight of
FIG 266 washing syrup which has replaced the molasses ; an example

is appended.

Weight of massecuite, 200 grms. ; weight of washed crystals, 175 grms. ;
percentage of water in washed crystals, 6-54. Then total moisture in

washed crystals = - = 12-62, and wash liquor in washed crystals

= 12-62 X 3-125*= 35-77 grins., and weight of crystals 175 — 35-77 = 139-23
grms., or 69-66 per cent, on weight of massecuite.

Duponfs Method1*. — Heat the massecuite to a temperature of 80°C. and
centrifugal in a small hand machine, the wire basket of which is covered with
thin flannel or some similar material ; polarize the molasses and the cured
sugar and calculate the percentage of crystallized sugar from the following

ft ___ /Yl /

formula : x = *-% where x = weight of crystallized sugar in one part of

P — P
massecuite, a the percentage of sugar in the massecuite, p the percentage of

sugar in the cured crystals, and p1 that in the molasses.

This formula is applicable for use on the factory scale, provided no water
is used in curing, and that the molasses are filtered through flannel before
analysis so as to remove fine crystals ; if water be used in small quantities
and if the amount can be calculated, the sugar percentage of the molasses can
be corrected for dilution, but in this case the formula will not give results
so correct.

* For a temperature of 84° F.
485

CANE SUGAK.

Geerligs* Method.15 — This method depends on the observation that sugar
•crystals themselves only contain a trace of ash, the ash of commercial sugars
being due to the accompanying molasses ; hence, in a massecuite the ash is
•due solely to the molasses. Determine the percentage of ash in the massecuite
and in its molasses freed from fine grain by filtration through glasswool ; as an
example, let the massecuite contain 2*25 per cent, and the molasses
6-07 per cent, ash ; then the percentage of molasses in the massecuite is

:2'25

— - X 100 = 37-07 per cent. ; the remainder 63-93 percent, being crystallized

sugar.

Method used by the Writer. — On the plate of a Bucbner funnel, arranged
as in Fig. 256, is placed a layer of glasswool, after which the funnel is filled
^vith the massecuite under analysis. On connecting to the vacuum the
molasses, entirely freed from crystals, passes through.

Let x and y be the proportions of sugar in the massecuite and filtered
.molasses, respectively, and let 8 be the proportion of sugar as crystals per unit
•of massecuite.

Then x =. (1 — «) y -f *, whence s = - — -

This equation gives the amount of crystals of pure sugar ; actually, in
practice, the crystals are obtained with an adhering layer of molasses which
increases the weight as indicated by this analysis.

These methods have been described as applicable to massecuites ; they
are, of course, applicable to molasses to determine the quantity of fine grain
which has been separated on cooling or is present after having passed through
the mesh of the centrifugal basket.

Rapid Scheme for Technical Control. — 1. Weigh out from 150 to 200 grins,
of material, dissolve in water, and make up to 1000 c.c.

2. Determine the density of this solution with the Brix hydrometer;

^X^XlOOO
then the degree Brix or apparent total solids of the massecuite is —

where B and d are the degree Brix and the density of the solution respectively,
and w is the weight of the material taken.

3. Obtain the polariscope reading of the solution exactly as described for
the juice. Then the apparent per cent, of sugar in the massecuite is

T0~" wnere P i8 the polarization of the solution, N the normal weight

of the polariscope, and w the weight of material taken.

4. The apparent purity is obtained by dividing the apparent sugar per-
centage by the apparent Brix.

In many cases in rapid technical control it is only the apparent purity
that is required ; it is then only necessary to make up a solution to any con-
venient density and determine the apparent purity of this solution exactly as
described for juice.

486

THE ASSAY OF SUGAR HOUSE PRODUCTS.

Analysis of Filter -Press Cake.— Water.— Dry to constant
weight at a temperature of 105°C. The use of a vacuum oven, though
permissible, is not so necessary as in the case of juices and molasses, &c.

Sugar. — The amount of insoluble matter in filter-press cake is so con-
siderable that error is introduced if the volume is not allowed for. Well-
pressed cake contains on an average 40 per cent, of insoluble matter, which
occupies about 20 c.c. per 100 grms. ; the volume occupied by the insoluble
matter in 25 grms. is then about 5 c.c., and if this quantity be weighed out
and made up to 100 c.c. after addition of lead acetate, the polariscope reading
will indicate at once the apparent percentage of sugar ; or instead, the normal
weight may be weighed out and polarized after making up to 105 c.c.

In factories using the carbonation process, saccharates of lime may occur
in the press cake. Before polarization these must be decomposed ; the decom-
position can be effected by the passage of a current of carbon dioxide, or more
conveniently by the addition of a few drops of acetic acid.

Analysis of Sugars. — Polarisation.. — The routine of a polariscope
test of sugar is as follows : —

The normal weight of sugar is weighed out in a suitable vessel, transferred
to a 100 c.c. flask, and dissolved in water; if necessary the sugar solution is
clarified with lead acetate, then made up to 100 c.c., filtered, and the polariscope
reading of the solution obtained ; the result is the polarization, and on this
test sugars are bought and sold. It cannot be too strongly insisted on that the
polarization and the percentage of sugar as determined by the methods given
already, in which the manifold sources of error are eliminated, are two entirely
distinct terms.

In the determination of the polarization a minimum of lead acetate is
to be used, and a correction for volume of lead precipitate is not applied.

The water, ash, &c., are determined by the methods already given.

The Detection and Estimation of small Quantities of
Sugar. — Molisch's Reaction™ depending on the production of a red coloura-
tion by small quantities of sugar in the presence of sulphuric acid, is thus
carried out. 5 c.c. of concentrated sulphuric acid are placed in a test tube,
into which is then run 2 c.c. of the water supposed to contain sugar, followed
by the addition of two or three drops of a 5 per cent, alcoholic solution of
a-naphthol ; the contents of the test tube are shaken, and the colour produced
compared with that obtained with known quantities of sugar ; as little as one
part of sugar in 1,000,000 can be detected. If the sulphuric acid alone
produces the reaction it should be boiled to destroy organic matter before use.

PinoflTs Ammonium Molybdate reaction was originally given
as a test for 'glucose,' and is applied by Pinoff17 to levulose : 'I grin, of

487

CANE SUGAR.

material, 10 c.c. of a 4 per cent, solution ammonium molybdate, 10 c.c. water,
and '2 c.c. glacial acetic acid are heated at 95°C. ; levulose in three minutes
gives a fine blue colouration ; all sugars give the same reaction in the presence
of mineral acids. The writer modifies this test as follows : — To a suspected
water 2 per cent, of hydrochloric acid of 1*18 sp. gr. is added, placed in a test
tube, and heated on the water bath for five minutes ; an equal quantity of a
5 per cent, solution of ammonium molybdate is then added, and the heating
continued for five minutes ; in the presence of sugars a blue colouration is
produced, which may be compared with previously prepared samples. The
colour thus produced may be simulated by solutions of copper sulphate
prepared to represent the colouration produced by 1 part of sugar in 20,000, &c.

Analysis of Waste Waters.— Sugar is detected and estimated
in waste waters by Molisch's or PinofPs reactions given in a previous paragraph ;
if sugar is present in sufficient quantity, the waste waters may be concentrated
and the sugar determined by the polariscope, or as glucose after inversion.

Analysis of Cattle Food or Molascuit. — Cattle food is a
mixture of molasses and finely comminated megass, from 25 per cent, to 30
per cent, of the latter being used. It is usually sold on its percentage of
sugars expressed as glucose. The method used by the writer is as follows : —
About five grms. of material are introduced into a funnel and washed with
successive quantities of water until all soluble matter is removed ; the united
washings are inverted, neutralized, made up to 1000 c.c., and the glucose
determined by one or other of the methods already given. The fibre is
determined by drying the insoluble residue to constant weight.

A Soxhlet extractor may also be used for the separation of the soluble
matter from the fibre.

The Analysis of Limestone and Lime.— It is not general for
sugar factories to prepare their own lime, but in the carbonation process it is
necessary, and where a supply of limestone is abundant, as in Mauritius and
Barbados, it is cheaper to burn lime than to import. The choice of limestone
is important and it is advisable also to keep a check on the composition of the
purchased lime.

Moisture. — Dry 1-2 grms. to constant weight.

Sand, Insoluble and Organic Matter. — Dissolve about 1 grm. in hydro-
chloric acid, filter through a tared filter paper, wash and dry at 100° C. ;
weigh, giving the weight of sand, &c., ignite and weigh obtaining the sand,
the difference of the two weights giving the organic matter.

Soluble Silica. — Evaporate to complete dryness the filtrate from the
determination of the sand, &c. ; moisten the residue and again evaporate to
dryness, keeping the residue at a temperature of 120° C. for an hour after the

488

THE ASSAY OF SUGAR HOUSE PRODUCTS.

residue is apparently dry ; take up with hot water, filter and wash till free of
chlorides; dry, ignite, and weigh the residue 8i02.

Insoluble Silica.— Mix the residue obtained in the determination of the
sand with four or five times its weight of fusion mixture, composed of mole-
cular proportions of sodium and potassium carbonates, and keep at a red heat
for (half an hour after effervescence has ceased ; dissolve out with dilute
hydrochloric acid, evaporate to dryness and determine the silica as before.

Iron, Alumina.— Mix the filtrates from the determinations of soluble and
insoluble silica ; evaporate to convenient bulk, add ammonia till alkaline, and
heat till the solution smells only faintly of ammonia ; filter while hot ; wash,
dry, ignite, and weigh the precipitate as Ee203-fAl203. If there be present
any large quantity of iron and alumina after decanting off the supernatant
liquid, the precipitate should be dissolved in hydrochloric acid and
re-precipitated.

Lime.— Precipitate the lime in the filtrate from the iron and alumina
while boiling hot with ammonium oxalate ; allow to stand for six hours, and
filter, wash, dry and ignite the precipitate to constant weight and weigh as
CaO ; convert the lime to sulphate or carbonate by evaporation to dryness with
either sulphate or carbonate of ammonia and again ignite, and weigh as
CaS04, orasCaC03; CaC03 X '56 = CaO ; CaS04X '4118 = CaO.

Magnesia. — Precipitate the magnesia in the filtrate from the lime determin-
ation as phosphate by the addition of sodium phosphate ; agitate the solution
violently, and allow to stand for twelve hours ; filter, wash with dilute ammonia,
dry, ignite strongly, and weigh as Mg2P207 : Mg2P207 x *3604 = Mg 0.

As magnesia is detrimental to the value of good limestone, Geerligs has
given a scheme for its rapid estimation. Two grms. are dissolved in hydro-
chloric acid, evaporated to complete dryness, the residue brought into solution
with hydrochloric acid, boiled after the addition of a few drops of nitric acid,
and evaporated to small bulk. An excess of calcium carbonate is added to
precipitate iron and alumina, the precipitate filtered off, and the filtrate
collected in a flask to which an excess of lime water is added ; the flask is
filled nearly to the neck and set aside to settle ; the supernatant liquid is
decanted through a filter, and the precipitate washed by decantation. The
precipitate from the lime water contains the magnesia ; it is dissolved in
hydrochloric acid, the lime precipitated as before by ammonium oxalate, and
the magnesia determined in the filtrate.

The method of Sundstrom for the rapid estimation of magnesia in lime-
stones is as follows : —

Weigh out one grm. of material into a small dish, add about 100 c.c.
water and 25 c.c. of normal hydrochloric acid ; heat to boiling, allow to cool
and titrate the excess of acid with normal caustic soda, thus obtaining the

489

CANE SUGAR.

quantity of acid required to neutralize the carbonates of lime and magnesia.
The lime is determined as usual and calculated to carbonate ; if the percent-
age of calcium carbonate be divided by five, the quotient will give the number
of c.c. of normal hydrochloric acid required to neutralize the calcium carbonate ;
the difference between that found above as necessary to neutralize the lime and
magnesia carbonates, and the calculated number of c.c. necessary for the lime
alone, gives the number of c.c. requisite to neutralize the magnesia carbonate ;
this number, multiplied by 4 2, gives the percentage of magnesia carbonate.

Sulphuric Acid. — Dissolve about five grms. in dilute hydrochloric acid ;
separate the silica as before, and in the hot filtrate precipitate the sulphuric
acid by barium chloride ; allow to settle for six hours, filter, wash, dry, ignite,
and weigh as EaS04 ; BaS04 X '3427 = S03 : BaS04 X '5828 = CaS04.

The analysis of the lime is performed exactly as for limestone ; very often
large quantities of alkalies are found in the lime, especially if the limestone
has been burnt with wood fuel in a short flame kiln. In addition to the
chemical analysis of the lime, a mechanical bulk analysis for the determination
of stones, unburnt limestone, &c., maybe made; very considerable quantities
of these materials are often found. The following are special methods of lime
analysis : —

Free Lime. — Dissolve about one grm. of lime in a 25 to 30 per cent,
solution of sugar ; make up to definite volume, filter and titrate an aliquot part
of the filtrate with normal acid.

Unburned and Slaked Lime. — Dissolve about one grm. of lime in a definite
quantity of normal acid and determine the excess of acid by titiation with
normal alkali ; the difference between the total lime as thus found and the free
lime as found above gives the unburnt lime.

Degener-Lunge Method. — Slake about one grm. of lime with water and
titrate with normal acid, using phenacetoline as indicator. The point at which
the indicator changes from yellow to red marks the neutralization of the free
lime ; the addition of acid being continued, the point at which the unburnt
and slaked lime are neutralized is marked by a change from red to golden
yellow.

490

THE ASSAY OF SUGAR HOUSE PRODUCTS.

REFERENCES IN CHAPTER XXIV.

1. Wiley, Agric. Anal, III., 22.

2. Chem. News, 52, 280.

3. Bull. Assoc., 1893, 656.

4. I.S.J., 110.

5. 7. S. .A, 80.

6. Handbook for Cane Sugar Manufacturers, p. 113.

7. ZtoZZ. ^Issoc., 1897, 74.

8. /. 8. J., 68.

9. /. 8. J., 79.

10. Arch., 1908, 3.

11. I. S. J., 120.

12. Bull. 32. Agric. H.S.P.A.

13. U.S.D.A. Bur. of Chem. Bull. 107.

14. Quoted in Spencer's Handbook.

15. 8. C., 309.

16. Wiley, Agric. Anal., III., 195.

17. Ber. Dent. Chem. Gesel. 38, 3308.

491

CHAPTER XXV.

THE CONTROL OF THE FACTORY.

By the term ' chemical control ' it is not meant that the control of the
factory should be given over to any one but the manager, but there is implied
a system of routine analysis and sampling combined with an organized scheme
of technical book-keeping whereby the chemist can detect, locate, correct and
hence control any imperfections of the process of manufacture.

To obtain this end three postulates are demanded, correct weights, correct
samples and correct analyses ; neglect of any one of these three will vitiate
the control, but as shown in some sections below incorrect measurements may,
in some cases, be indicated from analytical data alone and it is not the least of
the duties of the chemist to check the weights against the analyses ; this is
particularly the case where the cane is bought or where its weight forms a
basis of payment for the labour.

In addition the sugar factory should be regarded as a huge chemical
experiment and efforts should be made to account for every pound of sugar
entering the factory. The points necessary to the control as denned above are
discussed below.

Direct Measurements. — Canes. — What is regarded as the weight
of cane is not the same in all factories ; in some the gross weight is used and
in others an arbitrary allowance is made for trash, dirt, &c. ; there can be no
doubt that, for control work, the weight of cane should be denned as that
material which actually passes between the rollers of the mills.

The balances used to weigh canes are of the conventional type ; they
should be repeatedly checked and adjusted and the (in general) native clerk
should be carefully watched especially when the weight of cane forms a basis
of payment to contractors or when canes are purchased from native planters.
."Balances automatic in action and self -registering are to be bought, and these
are beyond the control of the operator whose functions are merely mechanical.

Juices.— In most factories the determination of the weight of liquids is
obtained from volume measurements and when carefully conducted and con-
trolled accurate estimates are possible. The most convenient scheme is to
employ two or more tanks for the reception of the cold juice, which also may
serve as liming tanks ; in each of these tanks a slot is cut on one side and the
flow of juice is continued until it freely overflows ; a constant volume is thus
ensured; the overflow is received in a gutter and returns to the juice pump
tank. The volume of juice combined with density and temperature

492

THE CONTROL OF THE FACTORY.

observations gives the data to calculate its weight. Tanks of symmetrical
pattern can be readily gauged, and if there is reason to suspect their sym-
metry they must be calibrated by filling into them water from some convenient
measure such as a 100 gallon cask.

In some factories conveniences for measuring the cold juice are absent and
it is only possible to measure the hot juice ; allowance must then be made for
expansion and for evaporation. Taking the volume of a 15 per cent, sugar
solution at 84°F. as unity, the volume at 180° F. is 1-0216, at 185° F. is
1-0285, at 190° F, is 1-0303, at 195°F. is 1-0327, at 200° F. is 1-0345, and at
205° F. is T0377; the expansion of the juice is so great compared with the
expansion of the receiving tanks and so many other sources of error are
introduced that change in volume of these may be neglected.

The weight of water evaporated in heating is given by the following

7? 7?

formula : — Weight of water evaporated per unit of evaporated juice = 2 -

-"i
where £l and J92 are the degrees Brix of the raw and heated juice

respectively.

Howe Juice Scales. — In the Howe scales
two tanks are arranged on a weigh bridge; when
one tank has received so much juice as to
approach a pre-arranged limit, the flow to that
tank is cut off ; balance is made by an attendant
adjusting a sliding weight ; pulling a lever
stamps on a card the net weight contained; the
tank then discharges its contents while the
second one is filling.

Baldwin* t Juice Weigher. — This appliance
for automatically weighing the juice is illus-
trated in Fig. 267 ; the drum c is divided into
compartments, of which one is filling while

another is emptying ; this drum is suspended from one end of a steel yard ;
juice flows into one compartment from the tank a and when balance between
the drum and its contents and the counterpoise w is obtained, the flow of juice
is automatically turned into the other compartment; as this compartment fills,
the drum soon revolves and discharges the juice from the weighed compartment ;
when balance is nearly obtained, the flow of juice from a is moderated
automatically; at each weighing a small sample of juice is diverted into
a bottle.

Hedemann Weigher.— This appliance is constructed by the Honolulu Iron-
works ; it consists (Fig. 268) of a container a a divided into two compartments
by a partition ; this container is mounted on a knife edge ; arranged along its

493

FIG. 267

CANE SUGAR.

upper edge is a hollow pipe I b, partly filled with mercury ; the juiee, first
of all, flows into the overhead receptacle d and thence discharges into
one compartment of the container a a; when a certain amount of juice
dependent on the quantity of mercury in b I has flowed in, the compartment
tilts and dumps its load. The juice now flows into the other compart-
ment, and when the same quantity has flowed in the same action again
takes place. Itiis necessary to calibrate the amount of juice discharged at each

FIG. 268.

dump by actual experiment ; a counter registers the number of dumps and a
sample of juice is taken at each dump from the cock g ; an arrangement of air-
cushion cylinders at c serves as a dashpot to prevent shock.

Richardson Weigher.1 — This apparatus is shown in Fig. 269 ; it consists
of a strong iron frame, supporting the equal armed beam A ; to one end of the
beam is hung the weighing tank or hopper, £, in which the liquid is carried,
and to the others is suspended the counter balance or weight box, C.

494

THE CONTROL OF THE FACTORY.

The quantity determined on is represented by the weights placed in the
weight box, which furnish the power to actuate the scale. The supply of the
liquid into the scale is from the upper hopper tank, D, which is fed by the
feed, E, which forms its joint by descending on to the rubber seating, F.
This valve is raised through the plunger, G, by the power of the weight in
the box, C, and is controlled by means of the levers, JTand Z, which'form a
dead centre.

Fia. 269.

A full stream of liquid enters the weighing tank, B, until its weight in
the hopper begins to off-set the counterpoise, and in so doing releases the
plunger, G. The valve now partially closes and only a reduced flow enters
the hopper until the balance is reached. This final flow may be enlarged or
reduced, by means of the screw J. At the balance, the beam trips the arm,

495

CANE SUGAR.

W, and the valve completely closes. The lever, Z, engages with the lever, N,
breaking the lock formed by the dead centre of levers N and Jf, and the
weight of the liquid opens the outlet valve and the contents of the tank are
discharged. This discharge is controlled by the conical valve, H, which also
has a rubber seating, and thus a joint is formed against the wall of the tank
at 8.

It will be seen that the liquid is delivered on to the tun-dish, Q, connected
with the outlet valve, ZT, and the weight of the liquid on this tun-dish has the
effect of holding the valve open until all the liquid is drained from the
weighing tank. This valve returns by means of the weighted lever, M, when
relieved of the weight of the liquid on the tun-dish, Q.

The sides of the tank are continued down to prevent splashing, and a
mechanical counter, It, registers every weighing.

This apparatus has been installed at Puunene, at Oahu, and at
Bay, which are among the largest factories in the world.

FIG. 270.

Leinert Meter. — This apparatus (Fig. 270} consists of two tanks of equal
-capacity Al and A^ ; they are balanced on a knife edge B • at C is a syphon
pipe and at D is arranged an adjustable counter-weight. The juice discharges
from the pipe E into the gutter F which is tilted one way or the other by the
movements of the tanks ; the juice flows into one tank until the weight is just
sufficient to counterpoise that at D, when the tank tilts into the position shown
by the dotted lines and allows the juice to discharge through the syphon ;
simultaneously the gutter is tilted and directs the flow of juice to the other
tank ; the number of fillings is registered by an automatic counter.

Megass. — It is only exceptionally that the weight of the megass is
directly determined, although this would afford a control of great value. In
some Demerara factories, where water carriage presented great difficulties for

496

THE CONTROL OF THE FACTORY.

a direct weighing of cane, it was once customary to receive the megass in
trucks passing over a weigh bridge ; the economies to be obtained by the
adoption of automatic firing led to the abandonment of this scheme. The best
means of weighing the megass is afforded, the writer believes, by the use of a
travelling band weigher, such as the Blake-Dennison. Actually in practice it
is general to obtain the weight of the megass from the ratio of the fibre in
cane and in megass.

Added Water. — Any of the appliances used for obtaining the
weight of the juice are of course equally applicable to obtain the weight of
the added water ; actually, however, the only direct measurement the writer
has ever seen used is by the employment of two tanks, one filling while the
other empties. The weight of water added is usually deduced from the

equation —

Canes + water = mixed juice •+• megass,

the weight of megass being obtained from the ratio of the fibre in cane to
fibre in megass.

In a subsequent section it is shown how the weight of added water can be
calculated from analytical data and one direct -measurement of any one of the
above quantities.

It must be carefully borne in mind that the water usually calculated as
present in the juice does not represent the whole amount added since a part of
this goes away in the megass and that the dilution represents only the dilution
on the amount of juice expressed.

Weight of Press Cake. — The press cake can be easily weighed in
the trucks in which it is received for removal ; if this is not possible a figure
of reasonable accuracy can be obtained by determining the average weight of
one press, and by keeping a tally of the number of presses filled.

Weigfllt of Syrup. — The weight of syrup can be obtained from a
record of the number of tanks filled combined with determinations of its
•density ; to be of value this record must be made with the same care as is
afforded the measurement of the juice.

Weight of Massecuites. — It is only in exceptional cases that
the factory arrangements are such that the massecuites can be weighed, and
in general their weight is deduced from volume measurements in combination
with observations of their density.

Weight of Waste Molasses.— The weight of waste molasses is
usually obtained from observations of the volume and density of the low
massecuites combined with observations of the weight of sugar obtained on
purging. In some Hawaiian factories it is the practice now to weigh all the
waste molasses on beam scales before they are finally discharged.

497

32

CANE SUGAR.

Weight of Sugars. — This quantity is always carefully weighed, in
some cases on automatic scales ; these machines which automatically fill a
fixed quantity of sugar into the bags, and also register the number of bags
filled, only work to their best advantage with very dry sugars.

Density of Absolute Juice of the Cane. — As shown in the
following section a knowledge of this quantity or of its relation to the density
of the first expressed juice affords a basis for an oversight of the recorded
weights and measurements. The writer has used the following scheme : —
The sample of cane is crushed in a hand mill, and from the weight of megass-
obtained the weight of juice expressed results ; the density or degree Brix of
this juice is obtained. A sub-sample of the megass is taken, extracted
in a Soxhlet apparatus, the extract concentrated to small bulk, say, 50 c.c.,
and the density of this extract obtained ; the refractometer forms a most
useful appliance in this determination. An example of the method follows : —

Weight of cane, 1000 grms.

Weight of juice, 670 grms.

"Weight of megass, 330 grms.

Juice was of 20*0° Brix ; the megass contained 50'0 per cent, water; the
extract, from 20 grms. of megass concentrated to 50-0 c.c., contained 4-2 per
cent, solids, and was of density 1-0165 ; the soluble solids in 20 grms. of

megass are then - — - =2-135 or 10-67 per cent. ; the megass

then contains 60-67 per cent, of juice, which contains 17' 61 per cent, of soluble
solids ; the amount of juice in the megass is per 100 cane 33 X '6067 = 20-02;

the Brix of the whole juice of the cane is then = 19*43

o7 -j- zu'UjiS

and the ratio of Brix of whole juice to Brix of crusher juice is — — — = -9715.

Inferential Control Of Weights.— When the Cheribon cane
formed the staple cane of Java it was found that the relation

sucrose in cane

• — 7* — I — MT"^ — : — — - *°"

sucrose in first mill juice

obtained very generally and this factor was used to obtain a preliminary
estimate of the weight of cane and it was also used to control the weights, as
if a different factor was found it was considered prima facie evidence of an
error in weights or analyses.

With the substitution of other canes it was found that this factor was
subject to variation and could no longer be used.

Nevertheless the writer thinks that the determination of this factor on
large samples of cane in a hand mill might reasonably form a part of the daily
routine, the figure so found being compared with that obtained from the factory
results ; any large difference would indicate an error which it should be the
business of the executive to locate and to rectify.

498

THE CONTROL OF THE FACTORY.

Another inferential control of the weights is obtained by the use of the
following equation —

Canes -f water = mixed juice -f megass ;

data for solution of this equation can be obtained from the ordinary routine
analyses and one measurement as under.2 Let / be the fibre in cane, m be
the fibre in megass, Bc, Bj, Bm be the degrees Brix respectively of the absolute
juice, mixed juice, and residual juice in the megass. Let the weight of canes
be unity and the weight of the mixed juice be a; from well-known equations

the weight of raegass is— and the weight of the juice in the megass is— (1 — m).

The total weight of juice is then a -\ (1 —m). The solids in the total

weight of juice then are

a BJ +-/.(! -W) Bm

M

and the total solids per unit of juice are

a Bj +-/-(! _i») Bm

-m) Bm

am + / ( I — m)

The water added per unit of original juice in the cane is then

Bc - a Bj m + / (1 - m) Bm
_ a m -f- f (1 —m) _
a Bj-m + f (l—m) Bm

a m -\- f (1 — m)

_a Bc m -f / Bc - f m Bc - a Bj m - f Bm + / m Bm
a Bj m + / Bm - f m Bm

Let this expression be denoted by P. The weight of original juice is
1 — /; hence the total weight of added water is (1 — f) P. Hence from the
equation —

Canes -f- water = mixed juice + megass

A numerical example will show the application of this equation.
The following analytical data (expressed per unity) were found : —
Bc -209 (i.e., 20-9 Brix) ; / '119 ; m '487 ; Bj -190 ; Bm '088 ; hence
— -2443 and 1 -/= '881.

From these quantities P is found to be

•00930 + -0074

•09250 + -0054
Whence

,-00930 + -0074X

1 + -881(- - ) =a+ -2443.

V-09250 + -0054'

499

CANE SUGAR.

Solving this equation, a is found to be -9125, i.e., the weight of mixed
juice is 91-25 per cent, of the weight of the cane, and if the actually observed
records do not agree with this determination then an error is indicated as being
present.

In the above argument Bc is the quantity represent-
ing the total solids in the whole juice in the cane ; it is
not usual to determine this quantity directly and in some
factories it is even customary to take the Brix of the
first expressed juice as representing this quantity.

The factor connecting the Brix of the first expressed
juice and the Brix of the whole or absolute juice of the
cane is capable of ready determination ; the equation
obtained above may also be used to obtain the relation
between the Brix of the first expressed juice and the
absolute juice, the actually recorded weights of cane and
juice being employed; the factors found from analysis
and from the recorded measurements should agree ; a
difference indicates an error.

With canes of 12 per cent, fibre and first expressed
juice equal in weight of 60 per cent, of the cane, the
writer has found that the following relation holds : —

(Brix of first expressed juice) -97 = Brix of absolute juice.

FIG. 271.

Automatic Record of Density. —

Langen's Apparatus for recording the density
of the juice is shown in Fig. 271 j the juice
enters a containing vessel /and overflowing
at d passes away at h ; a constant level of
juice is thus maintained ; inside the narrow
central portion of the vessel is a tube s, to the
lower end of which is attached a rubber ball g ;
the upper portion of this tube is funnel-
shaped ; this inner tube is filled with water ;
the height of the water is dependent on the
pressure on the rubber ball, the pressure
being in turn dependent on the density of the
juice. The level of the water is recorded by
means of the float 0, which carries a pencil a
pressing against the cylinder b, which revolves
by a clockwork arrangement every 24 hours ;
the lower portion of the inner tube is formed into a spiral at
the juice and water being of the same temperature.

D

FIG. 272.

so as to ensure

500

THE CONTROL OF THE FACTORY.

Horsin -Dean's Apparatus, shown diagrammatically in Fig. 272, is designed
to record the height of the juice in the receiving tanks. A wire or chain a a
transmits motion from a float b in the tank to a drum c which revolves when
the float rises or falls ; a pinion d on this drum in turn drives a rack e which
carries a pencil / pressing against a cylinder g which revolves once in every
twelve hours ; the height to which the pencil rises is governed by the height
of the juice in the tank, and, conversely, the pencil will show if the measuring
tanks have been properly emptied or whether through .carelessness any
1 running on bottoms' has occurred.

Dilution. — The dilution is calculated either as a percentage on the
normal juice expressed or as a percentage on the mixed juice. If Bl and JB2
are the degrees Brix of the normal and of the mixed juice, then water present

7? 7?

in mixed juice per unit of normal juice is given by the expression — ^—= - -

and per unit of mixed juice by the expression

B — £

In this calculation it is not unusual to take Bl as the degree Brix of the
first mill juice ; in other cases a factor is used to connect the Brix of the first
mill juice with that obtained when the mills work without added water.

Extraction. — The extraction is the amount of sugar obtained in the
juice per 100 sugar in canes; where direct measurements are used this
figure is at once obtainable ; in the majority of cases this is not the case and
resource must be had to inferential methods which were first used by leery.3
If /be the fibre in the cane, and m be the fibre in the megass, then the weight of

megass per unit weight of cane is — and the weight of juice per unit weight of

cane is 1 — — = - - . Consequently if the fibre in the cane and in the
m m

megass are known, and also the weight of either the juice or the megass, the
other data can be calculated ; an example is appended.

Recorded Data.— Tons of cane 550 ; tons mixed juice 500 ; fibre in caiie
11 per cent.; fibre in megass 44 per cent.; sucrose per cent, in mixed juice
13 per cent. ; sucrose per cent, in megass 4*0 per cent. Then

Tons megass = — X 550 = 137-5
44

Tons sucrose in megass = 137*5 X *04 = 5*5
Tons sucrose in juice = 500 X * 13 = 65-0
Tons sucrose in cane = 65-0 x 5*5 = 70-5

Extraction = -- - — - = 92*19 per cent.
70'5

Sucrose per cent, in cane = - = 12*81 per cent.

550

501

CANE SUGAR.

The extraction can also be obtained from analytical data only without

any weighings, as under :

Per cent.

Sucrose per cent, in cane (from analysis) , . . . 12-81

Sucrose per cent, in megass 4-0

Fibre per cent, in cane H*0

Fibre per cent, in megass 44-0

Then megass per 100 cane = 100 X — =25'00

25 X 4
Sucrose in megass per 100 cane = 1QQ — 1-00

Sucrose in juice per 100 cane = 12*81 — I'OO — 11-81

Extraction =

11-81 X 100

12~781 — = 92<19Per cent
Then if the weight of cane is known the sugar entering the boiling house
is readily calculated.

Sampling1 Juices. — Where the juices are received in tanks, no better
•scheme can be devised than to take a fixed quantity from each tank or if the
tanks are of unequal size a quantity proportional to the volume of each ; the
samples are stored in a large bottle in which has been placed an antiseptic ;
the preservatives most used are corrosive sublimate, one part to 5000 or a 40
per cent, solution of formaldehyde (formalin) one part to 2000. Allowance is
made for the corrosive sublimate in determining the density of the juice. These
preservatives will keep the juices unchanged for twelve hours but nevertheless
the containers used for sampling should be kept scrupulously clean.

Where the juice to be sampled is not measured, a continuous sampler
must be arranged.

FIG. 273.

Such a one is shown in Fig. 273 ; a is the main juice pipe into which is
fitted a short piece of iron or copper pipe, J, of half -inch internal diameter ; a
perforated cork carrying the bent piece of glass tubing c emerges from the end
of the pipe b and is continued to the bottom of the bottle d ; it is preferable to
make this pipe in two portions connected by a piece of indiarubber tubing ;

502

THE CONTROL OF THE FACTORY.

the glass tube e which delivers the juice to the receptacle / only extends to
the middle of the bottle d ; about one inch from the bottom of the bottle is
fixed a piece of fine wire gauze ; the end of the tube / is drawn out into a fine
point. The object of the bottle d is to act as a dashpot, and that of the gauze
to keep back fine particles which might choke the end of the tube e. By
connecting the tube e to a tall cylinder with a tubulure at the bottom as
shown at ^, the cylinder can be kept full with a continual flow of juice, and a
hydrometer placed therein will allow of the density of the juice being
continually under observation. Where the last mill juice is pumped separately,
this simple apparatus is invaluable in guiding the attendant at the water
tanks.

A very simple and convenient sampler may be arranged by connecting a
stout wire to the juice being sampled ; if, for example, the first mill juice is
being sampled, a large bottle, in the neck of which is a funnel, is placed close
to the mill ; a stout copper wire is then arranged so that one end rests on the
funnel, and the other leans against the mill roller ; the juice flows down the
vire and drips into the funnel, the amount of sample collected being
dependent on the size of the wire. In using this sampler it must be borne in
mind that the composition of juice from the front and back rollers varies very
much and especially so with maceration.

Sampling of Megass. — Well crushed megass coming away in a uniform
blanket is easily sampled, the only precaution necessary being to take
into account the megass at the ends of the rollers, which is frequently
imperfectly crushed ; it is hence best to take a large sample, going right across
the breadth of the mill, to mix this thoroughly and then to take a sub-sample
from the large sample. Megass when sampled must be weighed for analysis
at once, as it rapidly loses or absorbs moisture. Geerligs4 has shown that
megass can be preserved for indefinite periods by means of intermittent
sterilization in sealed vessels, but this process is, perhaps, too troublesome for
use except in special cases.

Sampling of Syrup. — A definite quantity of syrup is taken by the
attendant from each tank filled, and stored in a large bottle ; the analysis is
made on the accumulated samples ; if the bottles used are well washed and
kept strictly clean no preservative is necessary.

Sampling of Massecuites. — As each pan is struck, a sample of the masse-
cuite should be allowed to fall into a suitable vessel, such as a large wide-
mouthed bottle ; one sample from each pan strike is not sufficient, as masse-
cuite varies in composition in different parts of the pan, and a sample should
be taken at the beginning, middle, and end of the strike. When the receptacle
is full it should be sent to the laboratory for sub-sampling. Massecuites will
keep for long periods, and a daily analysis is not necessary ; an accurate
analysis of a massectiite, particularly of a low one, is a process which takes

503

CANE SUGAR.

considerable time ; a fully accurate analysis of a carefully taken week's sample
is of much more value than six inaccurate daily analyses.

Massecuites received in tanks for crystallization in motion are best
sampled after they have been stirred for a short time.

Sampling of Press Cake. — A hollow cylinder with bevelled cutting edge
may conveniently be used to bore out samples of press cake; it must be
remembered that the sugar content of press cakes varies largely with position.

Sampling of Molasses. — Considerable variations in the composition of
molasses as they leave the baskets may be observed, and it is better to take
the sample from the tanks in which they are received. In case the molasses
are run to waste directly, they should be systematically sampled at frequent
intervals.

Sampling of Sugars. — This is generally done by instructing the foreman
at the sugar filling station to throw a pinch of sugar from each bag filled into
a receptacle ; the writer prefers to take the sample from a large number of
bags from each consignment that leaves the factory. It must be specially
remembered that sugars lose or gain in weight very rapidly, and care should
be taken that the sample analysed, in so far as regards its percentage of
moisture, corresponds with the main body of the sugars from which it was
taken.

Control of the Milling Plant. — The most generally used figure,
as a criterion of the power exerted by the mills, is the water percentage of the
megass ; that this is not an accurate basis is shown by the following example : —

Let a megass be of composition : fibre 40 per cent., juice 60 per cent.,
the juice being of density 1'065 and containing 16'6 per cent, solids and 83*4 per
cent, water. The water content of the megass is then 50 per cent. Now suppose
for this juice an equal volume of juice is substituted of density Iv040 and
containing 10-5 per cent, solids and 89*5 per cent, water ; the crushing is
evidently equally good in both cases, but now in the second case the weight of
the juice is reduced from 60 to 58-6 and the weight of water increased to 52*45,
which calculated on the reduced weight of megass, 98-6 of the first weight,
gives a water content of 53-2 per cent. ; at the same time the fibre content
varies and for the example quoted is increased from 40 per cent, to 40-5 per
cent., a much smaller variation, so that the fibre content of a megass forms a
much more accurate basis of comparison. A true basis of comparison is given

by the expression

Weight of juice in unit weight of megass

Weight of fibre in unit weight of megass X density of juice
which expresses the volume of juice in megass per unit weight of fibre in the
megass.

A control or oversight of the efficiency of the added water can be obtained
by the use of the following methods5 : —

504

THE CONTKOL OF THE FACTORY.

1. The Density of the Last Mill Juice. — On the supposition that the density
of the juice is constant throughout the cane (a supposition that is not very far
from the truth) it is easy to ohtain the density of the last mill juice when
complete admixture is assumed. For example, let canes with 12 per cent, of
fibre be crushed until they contain 45 per cent, of fibre ; then the weight of juice

remaining in the megass per unit weight of cane is - = '1467;

*45

let this juice be of density 18°Erix, and let water 20 per cent, on cane be
added with complete admixture. Then the density after mixture, i.e., the

* 1467 x 18
density of the last mill juice is = 7*61.

In Table I., at the end of this section, is calculated for a single macera-
tion process the density of the last mill juice for degrees Brix in the normal
juice from 15 to 22, and for added water per 100 cane from 10 to 50, the
dry crushed megass containing 45 per cent, of fibre, and the cane containing
12 per cent, of fibre. As the mixture becomes less complete, less solids are
extracted, and the density of the last mill juice will fall. This table and
calculation is introduced as a means of checking the efficiency of the added
water.

2. Comparison of Last Mill Juice with the Residual Juice in Megass. — A
number of years ago it was the custom in Java mills to work out a * coefficient
of admixture of added water ' on the following lines :

Sugar per cent, in megass

Sugar per cent, in residual luice in megass=i- £ : X 100.

1 — fibre per cent, in megass

Sugar per cent, in last mill juice

Coefficient of admixture = jp — — . . . .

Sugar per cent, in residual ]uice

This figure does not appear in the more recent reports, and for this reason
the writer believes that it is no longer employed.

The figure as it stands is liable to misinterpretation ; if a small quantity
of water has been used a high coefficient must necessarily result, even if no
admixture whatever has taken place ; and as the residual juice always contains
less sugar than that already expressed, an accurate comparison on these lines is
impossible.

3. The Relation between Added Water per cent, on Canes and Dilution
per cent, on Normal Juice. — As the weight of the canes is greater than
the weight of the normal juice, it might appear that the figure giving the
added water per cent, on canes would be less than that giving the dilution per
cent, on normal juice ; a great part of the water added does not, however,
enter into the mixed juice, but passes away with the megass, and with
complete admixture the figure expressing the added water per cent, on canes
will always be considerably greater than that expressing the dilution per cent,
on normal juice. To obtain a comparative table of these figures one proceeds as
follows : The degree Brix is taken as being uniform throughout the cane ; let

505

CANE SUGAR.

the degree Brix be 18 ; let the canes contain 12 per cent, of fibre and be dry
crushed to 45 per cent, of fibre, after which with complete admixture water
20 per cent, on cane is added, and the saturated megass crushed to 50 per cent,
of fibre. In a dry crushing following on the equations already established
there are obtained 73*33 parts of juice at 18 Brix per 100 cane; 14-67 parts
of juice are left in the megass, which, when completely mixed with 20 parts
of water, give 34-67 parts of diluted juice at 7*61 Brix ; on crushing this
megass to 50 per cent, of fibre there are obtained 22*67 parts of diluted juice
at 7-61 Brix; this, when mixed with 73-33 parts of normal juice at 18 Brix,
will give 96 parts of mixed juice at 15-55 Brix, and the dilution per cent, on
normal juice is by the usual method of calculation 15*75 per cent. ; the added
water per cent, on cane at the same time being 20 per cent. In Table II., at
at the end of this section, is calculated for single maceration and complete
admixture the dilution per cent, on normal juice when water 10 per cent.
to 50 per cent, is added to canes containing 12 per cent, of fibre and dry
crushed to 45 per cent, of fibre, and after saturation to 50 per cent, of fibre.

Now if the admixture is incomplete, water passes into the mixed juice
without carrying in the sugar which it was the object of its application to
obtain, and the dilution will be higher than calculated above. Such a system
of comparison gives, then, an idea of the efficiency of the added water, and
may be used in the control or technical oversight of a mill, and it is to this
end that the calculation has been introduced.

4. A Method for expressing the Efficiency of the Added Water. — A control
or oversight of the useful effect of the added water is afforded, as has been
shown above, by comparison of the figures expressing the added water per
cent, on canes with the dilution per cent, on normal juice, and also by com-
paring the density of the last mill juice with the calculated figure when the
admixture is complete. A more exact and definite comparison may be
obtained by the use of the following methods :

In a plant employing a single maceration process, let the canes contain 12
per cent, fibre, and let them be dry crushed to 45 per cent, of fibre ; then on
the lines already established, the extraction due to the dry crushing is 85*82
per cent. Let water 20 per cent, on cane be added to the dry crushed
megass ; then with complete admixture and crushing to 50 per cent, fibre, a
further extraction of 9-20 is obtained. Suppose the actually recorded extraction
is 93*63 per cent. ; then that due to the saturation is 93-63 — 85-82 = 7'81.

1-1 .0 -I

What may be termed the efficiency of the added water is then — — = *849 ;

v' 20

i.e., the added water has extracted 84*9 per cent, of the maximum amount of
sugar possible. To apply this formula in actual practice demands a knowledge
of the fibre in the diy crushed megass, a determination that is not usually
made ; perhaps in actual work it would be sufficient to determine the average

506

THE CONTROL OF THE FACTORY.

extraction due to the dry crushing process (varied, of course, as tho fibre in
the cane varies) and to use the figure so determined in the calculation of the
efficiency of the added water.

Actually the amount of sugar extracted by mills falls short of that which
with complete admixture would be obtained with a single maceration process ;
the writer is of the opinion that the calculated figure for the extraction due to
saturation in a single maceration process might be made the basis upon which
the efficiency of the added water is expressed, independent of what system of
maceration is employed.

TABLE f.

Giving the density of last mill juice in a single maceration process
with complete admixture ; the dry crushed megass containing 45 per cent,
of fibre, and cane containing 12 per cent, of fibre.

Degree
Brix
of Normal
Juice.

WATER ADDED PER 100 CANE.

10

15

20

25

30

35

40

45

50

15

8-92

7-42

6-35

5-54

4-92

4-43

4-02

3-69

3'40

16

9-51

7-91

6-77

5-92

5-25

4-72

4-29

3-93

3-63

17

10-11

8-41

7-19

6-28

5-58

5-02

4-56

4-18

3-86

18

10-70

8-90

7-61

6-66

5-91

5-32

4-83

4-43

4-08

19

11-30

9-39

8-04

7-03

6-24

5-61

5-10

4-67

4'31

20

11-89

9-89

8-46

'7-40

6-57

5-91

5-37

4-92

4-54

21

12-49

10-38

8-88

7-76

6-90

6-20

5-63

5-16

4-76

22

13-08

10-88

9-31

8-13

7-22

6-49

5-90

5-41

4-99

TABLE II.

Giving, for a single maceration process, the density of mixed juice
and dilution per cent, on normal juice for canes containing 12 per cent,
fibre, dry crushed megass containing 45 per cent, fibre, and saturated
crushed megass 50 per cent, fibre, and normal juice containing 18 per
cent, of solids.

Added Water per cent.
on Cane.

Density
Mixed Juice.

Dilution per cent, on
Normal Juice.

10

16-92

6-38

15

16-23

10-90

20

15-55

15-75

25

14-89

20-88

30

14-27

26-14

35

13-69

31-49

40

13-15

36-88

45

12-65

42-29

50

12-18

47-78

507

CANE SUGAR.

Control of the Boiling House. — The basis of this is the amount
of available tugar in the mixed juice, i.e., that quantity of sugar which can he
obtained from that expressed by the mills.

In times past a number of irrational formula? based on the percentage of
glucose and of ash have been proposed ; the first rational one is that due to
Winter who from a study of actually recorded results in Java concluded that
one part of non-sugar prevented '4 part of sugar crystallizing ; expressed
algebraically this observation appears

Available sugar = S x f 1*4 — p . j

where S is the amount of sugar in the raw juice. In this formula the available
sugar refers to the gross weight of the commercial product.

The writer treats the matter as follows : —

In unit weight of a juice after removal of water let there be a parts of
sugar and b parts of non-sugar. Now let c parts of sugar be removed as in the
process of manufacture so that the residue (molasses) now is 1 — c ; let 1 — c
contain d parts of sugar per unit weight. Since the total amount of sugar was

0, the equation a = c + (1 — c\ d results. Whence — =—, -.

a a (I — d)

Now — is the proportion of sugar that has been removed and for a, which

is the proportion of sugar in dry material, the purity of the juice may be
written and for d the purity of the molasses.
The expression then becomes

Proportion of Sugar \

<, T, , ,. I purity juice — purity molasses .; — m

removed or Extraction } = —. — ^ — ; rA ; — = ^7\ "x

\ purity luicefl — purity molasses) Jil — m)

of Sugar in Juice )

where/ and m are the purities of the juice and molasses.

That is to say when the purity of juice and ipurity of molasses are known, the

corresponding extraction of sugar per 100 sugar in juice can be calculated.

The calculation above is an ideal one under conditions that are not reached
in practice, assuming as it does that pure sugar and not an impure product
containing a portion of the impurities is made ; the impurities contained in the
commercial sugar if replaced in the molasses would of course tend to lower
the actually observed purity of the molasses. The complete formula can be
obtained as follows : —

From a material containing a sugar and b non-sugar per unit weight, let
there be removed c sugar and d non-sugar and let (c + d) contain e sugar per
unit weight. The residue (molasses) is 1 — c — d and let it contain / sugar per
unit weight.

Then a = (c + d) e + (I - c - d) f or —

«(*-/)

or proportional gross weight of dry commercial _ j — m

sugar removed j (« — m)

where y and m are as before and s is the purity of the commercial product.

508

THE CONTROL OF THE FACTORY.

If the weight of wet commercial product is required, it is expressed hy the

formula : j— m 100

j (s — m} Brix of the Sugar

The only reliable basis of calculation and method of comparison as between
factories is, however, obtained by referring everything to pure sugar and we

then have

(j-m) 100 .. . . , . s (/-»Q *

Sucrose = 7— f X ~^-r- X sucrose per cent, in commercial product = -— -.

j(8—m) Brix j (s — m)

Expressed in words, this formula means that, with an initial purity of, say, 90,
a purity of 98 in the product, and a purity of 45 in the waste molasses per
100 sucrose originally present, there is obtained of sucrose in the commercial

'«°*S{£ESH-«-

More sugar than this cannot possibly be obtained, and the nearer the actually
recorded results come to the calculated ones, the less have been the losses of
sugar in filter presses, in entrainment, &c.

In cane sugar practice it is usual to accept the direct polarizations of
juice and sugars as giving the percentage of sucrose, and to use the Clerget
process only for the waste molasses. For the proper application of this control
true total solids and true sucrose deterihinations are essential, and these should
find a place in the routine work of every sugar factory where accuracy is more
highly considered than convenience. Difficulty arises in the application of
this control in considering what should be taken as the initial purity, and
whether the losses in press cake, entraiument, &c., should be considered as
avoidable ; these losses are not necessary in the same sense that molasses losses
due to the formation of a definite syrupy compound between sucrose and
saltsf are necessary, and in so far as they are determinable may be introduced
into the equation as indicated below. As regards the initial purity introduced
into the equation, that of the syrup might be taken as allowing for the
removal of impurities in the press cake and in scale formed in the evaporators.
The formula then appears as

Available sugar = (sugar in mixed juice — known losses) -77^ L

J (8 — m)

j, *, m being the true purities of the syrup, the commercial product, and the
molasses respectively. The formula established above can be put in the form :

Commercial sugar per cent, on massecuite = J" , — ,

Jft (s — m)

where Bm and Bs are the total solids in the massecuite and sugar, and /, *, m
are the purities of the massecuite, juice, and molasses.

* Formulse of similar form and obtained by different reasoning have been proposed
by Winter, Geerligs, Rose, Carp, Lohman, and Hazewinkel in Java, between the years 1894 and
1903. A complete discussion of these is given by Geerligs in the Dutch edition of ' Cane Sugar
and its Manufacture.'

t Cf. Chapter XIX.

509

CANE SUGAR.

Control of the Pan and Centrifugal Plant.— Following on
what has been written in the chapter on the vacuum pan, the cardinal points
in this control are the determinations of the sugar in crystal form, and of the
actual water content of the massecuites and molasses. A comparison of the
sugar actually present as crystals, with the amount obtained in the manufac-
turing process gives the amount lost either at a certain stage or totally lost in
the waste molasses ; this determination may be checked by analysis of the
molasses as they actually leave the baskets, and of the same molasses after
removal of fine grain by filtering through glass wool ; this source of loss is to
be looked for either in the pan (uneven grain due to lack of craft skill) or to
the use of an unsuitable mesh in the centrifugal gauze.

The systematic determination of the water content of the massecuites,
determining as it does the amount of sugar crystallized, is naturally of great
importance.

A systematic record of the working of the massecuites should be kept ;
the data recorded by the writer when engaged in supervising a crystallization
in motion plant included the following determinations : —

Date, number, density, volume, and weight of each strike ; purities of
the syrup and the molasses used and of the strike and purgings ; dry matter
in the strike and in the purgings ; weight and polarization of the sugar
obtained.

It may be mentioned that the apparent purities may be used in calcu-
lating the proportion of syrup and molasses to be used in making a strike.
Success in this department depends very largely on an organized system of
technical book-keeping.

Control of Entrainment Losses.— This term is usually taken
to include all undetermined losses, and much of this is due to errors of analysis.
Entrainment losses properly so called, due to sugar carried away mechanically
in vapours from the boiling apparatus, are, with modern well-designed plants,
reduced to a minimum ; nevertheless the waste waters from the evaporators
and pans should be systematically sampled and examined for sugar by one or
other of the sensitive colour reactions ; if any notable loss of sugar is indicated
the same may be determined by the usual methods after evaporation to small
volume of a large quantity of the suspected water.

Inversion Losses. — In a well-regulated factory these should be
entirely absent, even when white or yellow crystals are being made ; care-
lessness or the use of an excess of acid may lead to serious losses ; it is perhaps
impossible to estimate accurately these losses, since with alkaline juices there
is a tendency towards the destruction of reducing sugars ; hence any increase
in the glucose over that initially present is to be regarded as pointing to an
avoidable loss, the exact amount of which cannot be definitely stated.

510

2477-2

Less received from previous crop .

48-3

Due to present crop
Previously

2428-9
1910-8

Sucrose.
2258-7
1850-6

THE CONTROL OF THE FACTORY.

Stock-takings. — At fixed intervals a stock-taking of all the factory
products should be made ; the scheme used by the writer is as follows : —

Tons.

Sugar packed 2367*2

First massecuite estimated to give 43 '1
Syrup „ „ .. 8-3

Juice ,, ,, .. 3-2

Low massecuites 55-4

Per cent, on Sucrose
in Cane.

82-3
82'7

Current period 518'1 .. 408'1 .. 81'5

Expression of Results. — The writer is in favour of keeping two
sets of accounts, one for the mill and one for the boiling house, since the pro-
cesses in these two departments are radically distinct ; eventually these two sets
should be combined and a final statement made, showing the yield and losses
per 100 cane and per 100 sugar in cane. A statement based only on cane and
sugar in cane does not sufficiently specify the losses which, if excessive, may be
due to bad mill work or to inefficient work in the boiling house. The writer
has spent much time in trying to draw up a scheme, that will include in one
sheet all the necessary determinations, and has finally abandoned the idea in
favour of keeping separate books for the mills, for the juices, and for the pans.
The headings that should be systematically entered up are : —

Mills. Weight of cane ; sugar per cent, in cane ; fibre per cent, in cane ;
sugar obtained per 100 cane and per 100 sugar in cane ; dilution per cent, on
normal juice; water added per 100 cane; efficiency of added water; sugar
per cent, in megass ; water per cent, in megass per cent. ; fibre per cent, in
megass; sugar in megass per 100 cane and per 100 sugar in cane.

Juices. — Total solids, sugar per cent, and purity of first mill, mixed,
clarified, and last mill juices ; mixed juice per 100 cane ; sugar in mixed juice
per 100 cane and per 100 sugar in cane; available sugar with reference to the
actually observed purities of clarified juice and of waste molasses.

Sugars. — Weight; Sucrose per cent. ; weight of sucrose; sucrose per 100
sucrose in juice, per 100 sucrose in cane and per 100 cane ; tons of cane per
ton of sugar ; sucrose per 100 available sucrose.

Massecuites. — See above under the section headed ' Control of the Pan and
Centrifugal Plant.'

Waste Molasses. — Total solids, sugar per cent, and purity ; weight ;
weight per 100 cane ; sucrose per 100 cane and per 100 sucrose in cane and
in juice.

511

CANE SUGAE.

Undetermined Losses. — Sucrose per 100 cane, per 100 sucrose in cane and
per 100 sucrose in juice.

The exact way in which the forms are scheduled is so largely a personal
matter, that the writer does not offer a scheme, but thinks it best to leave
this to each individual interested.

Notes for Untrained Polarizers.— The following notes on
laboratory work are intended for the use of factories where a resident chemist
is not employed.

The Balance. — A chemical balance differs in no wise except in extreme
sensibility from any commercial balance ; but owing to the delicacy of its
construction, it must be treated with extreme care ; a few minutes use by a
careless operator being sufficient to destroy its accuracy. Chemical balances
are enclosed in tightly fitting cases with glass sides, access to the interior
being given by a sliding door in front ; the object of this is to protect the
balance from damp and dust, and during weighing from draughts and other
disturbing causes. As a further protection from damp, it is advisable to place in
the balance a dish containing strong sulphuric acid or calcium chloride, which
will absorb moisture and keep the inside of the case dry. A chemical balance
consists essentially of an upright pillar, usually of brass, in which moves a
second pillar which can be raised or lowered by turning a milled head screw ;
the top of the moving pillar is a plane surface of agate or highly polished
steel ; on this plane surface rests the beam which carries the pans ; the beam
is supported on the plane surface by a knife edge of steel or agate ; the pans
also hang on knife edges at the ends of the beams ; when not in use the pans
rest on the balance case, and by turning the milled head screw the beam and
pans are raised, leaving the beam free to swing ; from the centre of the beam
passes vertically downwards a pointer, the end of which moves over a scale,
and by observing the swing of the pointer the operator can tell when the beam
itself swings evenly.

When weighing on a chemical balance, determinations as to whether
exact balance is obtained are not made by letting the beam come to rest, but
by observing if the pointer swings through equal angles ; with a properly
sensitive balance it would take too long a time to let the beam come to
rest.

The weights used in the laboratory are always gram decimal weights ; a
set will contain one 50 gram, one 20 gram, two 10 gram, one 5 gram, one
2 gram, two 1 gram weights, and so on down to '01 gram ; weights smaller
than this are so minute as not to be conveniently handled, and the following
device is used: — The beam is divided into 100 equal parts, and a piece of wire,
called a rider, weighing exactly '01 gram, is arranged to be moved at will
along the beam, its effect being proportional to its distance from the fulcrum.

512

THE CONTROL OF THE FACTORY.

Steel knife edges are unsuited for a damp tropical climate, and balances
with agate fittings, though more expensive, are more satisfactory. The routine
of weighing out, say, an exact quantity of sugar is as follows : —

1. See that the balance is in equilibrium, when the vessel destined
to contain the sugar and the counterpoise supplied by the makers are in place,
and if not, adjust with small pieces of tin foil.

2. The vessel to contain the sugar being on the left-hand pan, place on
the right-hand pan the weight which it is wished to obtain, and approximately
the desired quantity of sugar in the containing vessel, then adjust the quantity
of sugar until balance is obtained. Never weigh any material directly on the
pans, and never place or remove anything from the pans when the beam is
free to move; the final adjustment should be made with the sliding door
closed.

When weighing out large-grained sugars, an exact
balance is difficult to obtain; in this case a little of the
sample can be crushed and the final adjustment made with
the powdered sugar.

The Burette. — A burette (Fig. 27 Ij) is a narrow cylin-
drical graduated glass tube provided with a cock at one end ;
by opening the cock any desired volume of liquid can be run
out. For laboratory purposes the graduation is made in one-
tenth of a cubic centimetre. Burettes are sent out by reliable
dealers very accurately calibrated and no appreciable error
need be looked for. The method of use is as follows : the FlG< 274*

burette is rinsed out with the liquid to be used, filled and placed in a vertical
position in the holder ; the level of the contained liquid is adjusted by opening
the cock until it corresponds exactly with some mark, say, 10*3; after a test
has been made the level of the liquid is again noted, say, 27*6 c.c., showing
that 17'3 c.c. have been used.

After use, if the burette is to be put away for any long period,
the cock should be wiped dry and smeared with vaseline ; if allowed
to dry with the liquid remaining, the cock will probably become
fixed, and efforts to remove it will possibly lead to fracture of the
instrument.

The Pipette. — A pipette, Fig. 275, is a special form of burette
designed to deliver one definite quantity of liquid. It consists of a
narrow piece of glass tubing in the centre of which is blown a bulb ;
on the upper part of the stem is a mark. The pipette is filled by
suction, the lower end being immersed below the level of the liquid
and the liquid aspirated up into the burette until a little above the level of
the graduation mark ; the filled burette is then smartly removed from the

513

FIG. 275.

33

CANE SUGAR.

mouth and the upper end closed with the finger ; by raising the finger slowly
the liquid is suffered to flow slowly out until the level of the liquid is
coincident with the graduation mark, then by pressing the finger firmly down
the flow is stopped and a definite quantity of liquid is contained in the pipette.

The first object of anyone working in a laboratory should be to keep
all apparatus scrupulously clean; all burettes, pipettes, hydrometers, &c., after
use should be rinsed with clean water and put to drain. Cleanliness is of
especial importance in a sugar laboratory.

REFERENCES IN CHAPTER XXV.

1. Chemical Engineer, 9, 4.

2. Bull. 30 Agric. H.S.P.A.

3. S. 0., I.

4. 8. C., 344.

5. Bull. 22 Agric. t H.S.P.A.

514

CHAPTER XXYI.

FERMENTATION WITH SPECIAL REFERENCE TO THE
SUGAR HOUSE.

This chapter treats principally of the fermentation of molasses and of the
manufacture of rum ; incidentally opportunity is taken to bring together some
part of the scattered articles dealing with the mycology of the sugar house.

Yeast. — By this term is loosely meant any organism which has the
property of fermenting sugars and producing mainly alcohol and carbon dioxide ;
in this sense organisms such as the Torulae, Monilia, and certain of the
Mucoraceae would be included, although these organisms are very distinct
from that mainly composing 'brewers' yeast,' which consists essentially of
SaccJiaromyces cerevisiae. Systematically production of alcohol is not an
essential character of the Saccharomyces although the greater number of species
here included do produce alcohol ; in addition some species ferment saccharose,
dextrose, maltose ; others dextrose and maltose only ; others lactose only.

A complete list of all the known ' yeasts ' is given by Kohl1 ; following
him they are divided into these groups : —

I. Yeasts proper or budding yeasts. Saccharomycetes. These are divided
into the following genera : —

I. Saccharomyces; 2. Hansenia ; 3. Torulaspora ; 4. Zygosaccharomyces ;

5. Sacchar omy codes ; 6. Saccharomy copsis ; 7. PicTiia ; 8. Willia.

II. Fission Yeasts, Schizosaccharomycetes. This includes one genus,
Schizosaccharomyces.

III. Yeast like fungi. These are divided into the following genera : —
1. Torula; 2. My coder ma ; 3. Monilia ; 4. Chalara ; 5. Oidium ;

6. Dematium ; 7. Sachsia; 8. Endomyces ; 9. Monospora\ 10. Nematospora.

In European and North American breweries and distilleries alcoholic
production is mainly produced by the species S. cerevisiae; a closely allied
yeast 8. vordermanii is responsible for most of the alcohol produced in
tropical countries from molasses ; in addition, fission yeasts have been observed
in the Antilles2, in Jamaica3, in Natal4, and in Peru5 ; they are of great
importance in the production of rum, but have not received the extended study
that has been given to the budding yeasts.

Yeasts of special Interest in Connection with Rum
Distilleries. — The first detailed study of any yeast in connection with the
cane sugar industry is that due to Went and Geerligs6, who isolated from
Raggi or Java yeast a species which they named S. vordermanii ; this is a
typical budding yeast.

515

CANE SUGAE.

In 1893 Greg3 isolated from Jamaican distilleries a fission yeast, Sch.
mellacei ; it is very similar to the first observed fission yeast isolated from
Kaffir millet beer in Natal ; this has been named Sch. pombe and described by
Lindner4.

Peck and Deerr5 collected yeasts from molasses distilleries in Demerara,
Trinidad, Mauritius, Natal, Cuba, Java, and Peru ; all except the last were
budding yeasts, very close if net identical with S. vordermanii ; the yeast
from Peru was a fission yeast very close to Sch. pombe.

In Figs. 276 and 277 (see PLATES XXI. and XXII.) are shown the yeasts
collected by Peck and Deerr. Fig. 276 shows the yeasts 36 hours old in beer
wort, the reference being as to district of origin: 1, Java; 2, a non-sporing
yeast from Natal, peculiar for its production of ethereal salts and referred to
in the text ; 3, Trinidad ; 4, Natal ; 5, Demerara ; 6, Natal ; 7, Cuba ;
8, Mauritius ; 9, Peru. The septum across which the Peruvian yeast divides is
not .shown ; division occurs symmetrically at right angles to a longitudinal
axis. Fig. 277 shows the same yeasts sporulating, the district of origin
being indicated by initial letters ; the sporulation was obtained on gypsum
blocks, except for the Peru fission yeast, which was obtained from an old agar
beer wort plate culture.

It may then be said that the production of rum proceeds under the
influence of S. vordermanii and Sch. pombe either separately or conjointly,
the fission and budding yeasts having been found together in Jamaican
distilleries. Of the other Saccharomyces the type represented by S. mali Dudauxi
is of interest. This species does not ferment saccharose and it has hence been
used by Pellet and Perrault7 to remove glucose from molasses in analysis; its
use on the economic scale has been patented by McGlaschan9 with the idea of
obtaining an increased yield of sugar.

Wild Yeasts. — By this term is meant a yeast other than the one
desired in any particular fermentation ; the term has a special significance
when used in connection with a pure culture process, i.e., one in which the fer-
mentation is intended to be carried on by one specific organism to the exclusion
of all others ; in a sense since the presence of yeast in molasses is adventitious,
molasses fermentations might be regarded as carried on by wild yeasts.

Other Organisms connected with Fermentation.9—

Perisporaceae. — This is an extensive order of fungi including amongst others
the well-known genera of Aspergillus and Penicillium, both of which are of
cosmopolitan distribution ; they have been studied chiefly in connection with
their action on grain and wines to which they give an unpleasant flavour.
Aspergillus oryzae is of interest as being the organism, to the diastatic action of
which is due the saccharification of rice starch in the preparation of the
Japanese spirit Saki ; Penicillium glaucum has been connected by Shorey10
with the deterioration of sugars.

516

FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE

Mucoraceae. — The Mucoraceae or pin moulds are of frequent occurrence as
objectionable organisms in distilleries; some of them can produce limited
quantities of alcohol. Mucor oryzae, which is perhaps the same as Rhizopus
oryzae, was isolated by Went and Geerligs9 from Raggi; this fungus can
saccharify starch, but does not produce alcohol. Mucor Rouxii, isolated from
Chinese yeast, has enjoyed some notoriety as an economic alcohol producer,
but does not now seem to be a likely rival to the Saccharomyces.

Fungi imperfecti. — By this term is meant those fungi the classification of
which is uncertain; included here are the Torulae (by which term is now meant
a non-sporing yeast-like organism fermenting sugar) and the Mycordermae or
true film fungi connected with the oxidation of alcohol to acetic acid. Momlia
iavamca was isolated by Went and Geerligs9 from Eaggi ; it produces up to
5 per cent, of alcohol to which it gives an unpleasant taste. An allied organism,
isolated by Peck and Deerr5 from a Natal distillery, was remarkable for its high
production of acetic and butyric ethers, as much as 7558 parts ethers as acetic
ether being produced per 100,000 of alcohol.

Bacteria. — Numerous bacteria are connected with the sugar fermenta-
tion industries ; a systematic account of such as have been studied herewith is
quite without the limits of the present work. It may be at once stated that
generally bacteria are a prolific source of disease and loss in distilleries,
especially in rum manufacture, although as shown later in grain distilleries at
one stage their presence is essential; to their presence may be attributed
imperfect attenuations and low returns. Some particular types of bacterial
activity of greater interest are briefly mentioned below, and it must be
remembered that in all cases the types of fermentation referred to in a heading
may be brought about by any one of a number of dibtinct organisms.

Lactic Acid Fermentation. — The importance of the bacteria
which produce lactic acid in green malt in cereal distilleries is shown in a
subsequent section ; they occur chiefly in sour milk and in green malt ; through,
their agency the production of lactic acid from beer wort has been proposed,,
and its production from molasses does not seem prima facie impossible; certain*
species have been noted as causing disease in beer.

Acetic Acid Fermentation. — This fermentation is economically
of importance in the production of vinegar from alcohol ; it may take place
under the influence of certain well defined bacteria or under that of an imperfect
fungus, referred to as Mycoderma vini ; generally it is essentially a process
of oxidation, but Watts and Tempany have shown that the spontaneous souring
of cane juice proceeds anaerobically, the sugar forming the source of oxygen.
Acetic acid has been observed by Grieg Smith11 in soured sugar, and sugar
or juices left in crevices about a sugar factory undergo this fermentation
and are responsible for the sour smell often observed ; wash kept after the
alcoholic fermentation is complete also undergoes acetic fermentation, and the

517

CANE SUGAR.

writer has knowledge of cases where consignments of * molascuit ' completely
underwent this fermentation in transit between Demerara and London.

Butyric Acid Fermentation.— This fermentation is technically
of importance in the rum industry as the flavour of fine rum is by some
authorities believed to be intimately connected with its presence ; in cereal
distilleries it is considered most harmful, as not only does it decrease the
yield of alcohol but also forms objectionable products as butyric acid and
butyl alcohol.

Viscous Fermentation. — This term has now only an ill-defined
meaning, but occurs frequently in older writings on fermentation ; it is used
in reference to fermenting liquids becoming ropy or slimy, and was once not
an uncommon phenomenon ; in European distilleries this disease has been
associated with certain well-defined bacterial species ; in rum distilleries it is
not unknown and may often be traced to lack of cleanliness and to attempting
to work with too little or no bactericide.*

Gumming. — The 'gumming' of cane juices has been studied by Greig
Smith,12 who found that this was due to a bacillus which he described and
named Bacillus levaniformans ; this organism is also one of several responsible
for the deterioration of sugars ; Lewton Brain and Deerr13 isolated from
Hawaiian sugars several forms which also produced large quantities of gum ;
formerly this fermentation would have been classed as a * viscous fermentation.'

LeuconostOC Mesenterioides.— This organism, known as 'frog
spawn,' has the faculty of converting sugar solutions into a gelatinous, viscous
mass; it is a well-known type and has been reported from Europe and Java where
it has been the cause of blocking up pipes used for the conveyance of juices.

Spontaneous Fermentation of Cane Juice.— Watts and
Tempany14 found that yeasts and an undetermined bacterium were concerned
in this process ; alcohol was produced by the yeast and acids by the bacterium,
of which about one third were volatile acids ; the fermentation was both aerobic
and anaerobic, and was inhibited by the presence of phenol indicating that already
formed enzymes do not play a very prominent part in the souring of juices.

Spontaneous Combustion of Molasses.— Crawley15 has recorded
a case of molasses on storage becoming charred, the damage being supposed to
to have been initially due to micro-organisms ; consignments of ' molascuit ,
have suffered a similar change on board ship.

Nitric Fermentation of Molasses. — In beet sugar factories the
after massecuites on storing sometimes show a nitric fermentation. A dense
red cloud of vapour due to the presence of nitrogen dioxide is observed to hang
over the massecuites; this is ascribed to decomposition of the potassium
nitrate present under the influence of bacteria, but really very little is known
on the subject. The writer is unaware of any similar phenomenon being
observed in cane sugar factories.

* The use of bactericides in distilleries is explained in a subsequent section.

518

FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE.

Foaming of Massecuites.— Geerligs16 explains the foaming of
stored massecuites as due to the spontaneous decomposition of glucinic acid
formed by the action of lime on reducing sugars. Ashby,17 however, has in
Jamaica isolated a yeast which is active in concentrations up to 80° Brix, and
attributes the phenomenon to the presence of these organisms.

Faulty Hum. — By faulty rum is meant a spirit which on dilution
with water becomes cloudy and throws down a deposit. The causes to which
this behaviour are attributed are : — The presence of caramels soluble in strong
and insoluble in dilute spirit ; the presence of higher fatty acids, due to
careless distillation, which are precipitated on dilution; the presence of
tcrpenes extracted by the spirit from the casks ; the presence of a micro-
organism capable of life and reproduction in 75 per cent, alcohol; the latter view
was brought forward by Y. H. and L. Y. Yeley18 who named the supposed
organism Coleothrix methystes and stated that it is extremely resistant to ordinary
methods of destruction, survives desiccation, is air borne, and both aerobic and
anaerobic ; in certain of their publications the organism is described as multi-
plying and living actively in 75 per cent, rum and in other places as merely
surviving in spirit. The whole of the results of Y. H. and L. Y. Yeley were
challenged by Scard and Harrison,19 who were unable to obtain any of the
effects noticed by the Yeleys. They found, however, in Demerara rums
remains of organisms similar to the one in question, and were of opinion that
faultiness in rum was due to the first three causes mentioned above.

When rum samples have been kept in an imperfectly sealed bottle so that
the spirit is free to evaporate, the writer has frequently noticed a slimy
mucinous growth appear ; this on microscopic examination is found to be of
a fungus character, and to be similar to that described by Yeley as the cause
of faulty rum. The writer has never observed it in strong spirit, but when
the fungus growth was transferred en masse to 75 per cent, alcohol, the
organisms were not killed but cultures could be obtained for over a year ;
the growth did not increase in size but remained suspended in the rum,
which remained quite clear ; when a drop of the original weak spirit con-
taining the fungus was inoculated into sound clear rum, no change whatever
took place. The writer thinks it quite possible that masses of the organism,
to the existence of which he gives credence, have found their way into casks
and puncheons, and have thus been present and alive on arrival in England,
but does not think they can be called the cause of faulty rum.

Deterioration of Sugars. — The deterioration of sugars on storage
is without doubt to be attributed to the action of micro-organisms. Shorey10
attributed it chiefly to the action of mould fungi, but more recent studies lead
to the conclusion that bacteria are mainly responsible. Grieg Smith20 was
inclined to attribute the damage to one specific organism, Bacillus
levaniformans, which he found originally in Australian juices and sugars
and afterwards in sugars of cosmopolitan origin ; this organism is char-

519

CANE SUGAR.

acterized by the abundant formation of a gum 'levan.' Lewton-Brain
and Deerr13 isolated five forms of bacteria from Hawaiian sugars, all of
which were capable of causing deterioration ; of these five it was found that
three were remarkable for the formation of a gum similar in properties to
'levan/ and these forms were the most dangerous. Morris and Deerr13
showed that sugars containing less than 1 per cent, of water were not liable
to deterioration, and Lewton Brain and Deerr proved that sterile sugars
under conditions favourable to deterioration remained unchanged. Bacteria,
as a cause of deterioration, have also been observed by Geerligs in Java.
The prevention of deterioration is best effected by the prevention as far as
possible of contamination of the products, as by rapid working (e.g., crystal-
lization in motion), the use of antiseptics about gutters and containers, the
use of sterile water at and about the centrifugals, and by controlling the
amount of water in the final product.

In Java the bags have been noted as a source of infection, but gunny bags
from Indian jute mills examined in Hawaii by Norris and Deerr21 were sterile.

It has been shown by Watts and Tempany22 that bacterial action in
muscovado sugars may actually cause a rise in polarization ; in this case the
levulose is first selected for attack.

Fermentation Changes in Massecuites. — Browne24 has
investigated the nature of the scum which is often seen to rise on to the
surface of stored massecuites to which he attributes a fungus origin ; he
obtained from this scum chitine, a fat very similar in composition to butter
fat ; he also reports encountering dimethyl ketol in sour molasses.

Manufacture Of Rum. — The manufacture of rum as a product of
the fermentation of cane juice or of molasses forms an important part of the
cane sugar industry in Demerara, Trinidad, Jamaica, Cuba, the Leeward
Islands, the French "West Indies, Hayti, and the Argentine ; rum is also
manufactured in connection with sugar mills in Peru, Mauritius, Queensland,
and Natal. Molasses form the source of the spirit ' arrack ' in Java, and are
also utilized in British India ; in these two localities however the manufacture
of spirit is divorced from the sugar industry proper. The writer has been
unable to obtain statistics of the annual production of rum, but believes the
total production cannot be less than 20,000,000 gallons of spirit containing
75 per cent, of alcohol.

Outlines of the processes used in different localities follow.

Demerara. — A process of adventitious fermentation obtains ; commercially
exhausted molasses form the initial product; the molasses are received directly
from the centrifugals, storage for a few days' supply only being provided.
The molasses and water — generally trench water — are usually mixed to the
required density in a mechanical mixer in the basement and pumped up to
the vats in the fermenting loft ; in other cases the molasses are pumped up to
the vat and mixed by hand with the requisite amount of water ; the density

520

PLATE XXI

FIG. 276.

PLATE XXII.

FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE.

of the mixture varies from 1*060 to T063 ; to the wash is added sulphuric
acid and sulphate of ammonia in the proportions of 1 gallon and lOlbs. per
1000 gallons; the acid is added to prevent the growth of bacteria, especially
the 'butyric acid' forms; fermentation sets in rapidly, and is generally
complete in 48 hours; the density of the fermented wash varies from 1-015
to 1-025, and is governed by the amount of sugar present and the action
of the yeast ; in some distilleries ammonium bifluoride is used as a bactericide
in place of sulphuric acid. This simple process is the one that generally
obtains elsewhere.

Mauritius. — In this district only one sugar factory possesses or did possess
(1901) a distillery as an annex ; the process there followed is as under: — A
barrel of about 50 gallons capacity is partly filled with molasses and water of
density I'lO and allowed to ferment spontaneously; sometimes a handful of
oats or rice is placed in this as a preliminary to fermentation. When attenuation
is nearly complete, more molasses are added until the contents of the cask are
again of density 1*10, then again allowed to ferment. This process is repeated
a third time ; the contents of the barrel are then distributed between three or four
tanks, holding each about 500 gallons of wash of density MO, and 12 hours
after fermentation has started here, one of these is used to pitch a tank of about
8000 gallons capacity ; a few gallons are left in the pitching tanks which are
again filled up with wash of density I'l, and the process repeated until
the attenuations fall off, when a fresh start is made. This process is very
similar to what obtains in grain distilleries save that the initial fermentation is
adventitious.

Java.zi — In Java and the East generally, a very different procedure is
followed. In the first place a material known as Java or Chinese yeast is pre-
pared from native formula. In Java, pieces of sugar cane are crushed along
with certain aromatic herbs, amongst which galanga and garlic are always
present, and the resulting extract made into a paste with rice meal ; the paste
is formed into strips, allowed to dry in the sun, and then macerated with water
and lemon juice ; the pulpy mass obtained after standing for three days is
separated from the water and made into small balls, rolled in rice straw and
allowed to dry ; these balls are known as Raggi or Java yeast. In the next
step rice is boiled and spread out in a layer on plantain leaves and sprinkled
over with Baggi, then packed in earthenware pots and left to stand for two
days, at the end of which period the rice is converted into a semi-liquid mass ;
this material is termed Tape/ and is used to excite fermentation in molasses
wash. The wash is set up at a density of 25° Balling and afterwards the
process is as usual. In this proceeding the starch in the rice is converted by
means of certain micro-organisms, Chlamydomucor oryzae, into sugar and then
forms a suitable habitat for the reproduction of yeasts, which are probably
present in the Raggi, but may find their way into the Tape/ from other sources.
About 100 Ibs. of rice are used to pitch 1000 gallons of wash.

521

CANE SUGAR.

Jamaica. — Allan25 gives the following outline of the process followed
in making flavoured spirit: — "The wash is set up from skimmings, dunder,
molasses, acid and flavour. Acid is made by fermenting rum cane juice
which has been warmed in the coppers. To this juice is added dunder and
perhaps a little skimmings. When fermentation is about over, the fermenting
liquor is pumped on to cane trash in cisterns and here it gets sour. Into these
cisterns sludge settling from the fermented wash is from time to time put.
This acid when fit for use smells like sour beer. Flavour is prepared by
running fermented rum cane juice into cisterns outside the fermenting house
along with cane trash and dunder that has been stored from a previous crop.
Generally a proportion of liquid from what is called the * muck hole ' is also
added to this cistern. The components of the 'muck hole' are the thicker
portion of the dunder from the still, the lees from the retorts, and cane trash
and other adventitious matter which from time to time finds its way into this
receptacle. From this cistern the incipient flavouring material passes on to a
second and third cistern filled with cane trash, and to which sludge from fer-
menting wash has been added. From the third cistern it is added to the wash.
Skimmings are run from the boiling house into cisterns half filled with cane
trash. This is allowed to remain four, five, or six days. When the skim-
mings are considered ripe, wash is set up with them. Fermentation lasts
seven to eight days. The time which elapses between setting up the wash
and distillation is from thirteen to fourteen days."

Process used in Grain Distilleries.24— It is of interest to
compare the above methods with those in use in cereal distilleries. The basis
of manufacture is grain ; this is ground to a coarse powder and a weighed
amount is placed in a digester mixed with water and heated by steam under a
pressure of two or three atmospheres for an hour or more ; the liquid contents
of the digester are then blown into a second vessel and cooled ; as soon as the
temperature falls below 63° C., a proportion of malt is added; the malt contains
a ferment, diastase, which converts the starch in the grain to a sugar, maltose ;
after the starch has been converted into maltose, the contents of the vat are
drawn off into a fermenting vat and rapidly cooled ; the vats are usually large
enough to hold a whole day's work, and a distillery will have generally six
fermenting vats, each of which may be of as great a capacity as 50,000
gallons. After the vat is set up it is pitched with yeast, and the temperature
and quantity of yeast regulated with the object of obtaining the maximum
yield of alcohol within the legal limit of time, i.e., 72 hours. The temperature
is regulated by means of water circulation through coils and maintained at
20°-25° C. ; the high temperature promotes a rapid fermentation, but
more fusel oils are formed than at a low one.

The preparation of the pitching yeast is as under : — A mixture of green
malt and water is warmed to about 70° C., kept at this temperature for about
two hours to allow the starch to be converted to maltose and soured. Green

522

FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE.

malt contains enormous numbers of bacteria, amongst which are the lactic and
butyric acid organisms ; butyric acid is a virulent yeast poison, and its develop-
ment would injure the yeast ; these organisms cannot be killed by raising the
temperature as this would also destroy the action of the diastase. The butyric
acid bacteria arc, however, themselves susceptible to slight degrees of acidity ;
in order to destroy them without injuring the yeast the temperature is arranged
so that the lactic acid bacteria can develop ; the optimum temperature of the
lactic acid bacteria is from 47° C. to 50° C., that of the butyric acid organisms
about 40° C. The mash is hence kept at a temperature of about 50° C.,
whereby the lactic acid bacteria thrive and the formation of lactic acid effec-
tually prevents the development of the butyric acid organisms. When the
acid present reaches 1-0 to 1-1 per cent., the process is stopped by raising
the temperature to 70° C. ; the mash is re-cooled to 20° C. and pitched with
yeast, in the proportion of about 1 Ib. to 10 gallons; after about 14-16 hours
the yeast has so far developed as to be used in the main process, a portion being
kept for the next sour mash.

This process left much to chance, and has been developed on other lines
although the object in view has always been the same. In the first place the
presence of lactic acid bacteria is adventitious, and although their presence is
very general, it not infrequently happened that the process miscarried by reason
of their absence ; to get over this difficulty the infection of the sour mash was
carried out by innoculation with pure cultures of lactic acid bacteria, and now
more recently a new process known as the hydrofluoric acid process has been
largely introduced.

It was sought for a long time to find some substance that would be
antiseptic to the butyric acid bacteria and yet harmless to the development of
yeast, and after many bodies had been tried Effront, in 1890, introduced the
use of alkaline fluorides. The initial proposition was to add from 4 to 8 grms.
of hydrofluoric acid per hectolitre (say from ^V— TTT^. per 100 gallons) of the
yeast mash which had been treated in the way described above, this quantity
being found sufficient to prevent the development of injurious organisms.

Composition of Rum. — Hum has now been defined as a spirit
distilled from fermented products of the sugar cane in a country where the
sugar cane is grown. This definition shuts out the use of the term for spirits
distilled from cane molasses imported to Europe or North America, and does
not differentiate between a juice and a molasses spirit ; originally the term
rum was applied to the former and tafia to the latter.

Bum consists mainly of alcohol and water, the other bodies present being
caramel (in coloured rums), fatty acids, ethereal salts, aldehydes, higher
alcohols and essential oils ; the acids known to be present are formic, acetic,
butyric, and capric, both free and as ethereal salts. Miller26 has given the
following analyses of Demerara rums : —

523

CANE SUGAR.

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524

FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE.

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525

CANE SUGAR.

In consequence of an abortive prosecution for selling Demerara rum as
Jamaica rum, Harrison29 examined the ethereal salt content of Demerara rums,
finding a variation from 23'7 to 141*6, with a mean of 64'7 parts per 100,000 ;
pot still rums contained on an average 69'9, and continuous still rums 44*9
parts per 100,000 of alcohol.

In Jamaica rums, classed as • common clean/ Cousins30 found 200-300,
in high-class ordinary rums 300-400, and in the best flavoured 1100 and
upwards parts ethereal salts per 100,000 of alcohol.

The Flavour of Rum. — It is generally held that the peculiar fruity flavour
of rum is due to the presence of ethyl ethers, particularly the butyrate and
caprylate. It has been shown by Cousins that these ethers, particularly the
latter, are present in very minute quantity, and that the ether predominantly
present is the acetate; compared with the other ethers the acetate and butyrate,
particularly the former, are volatile and these serve as a means whereby the
heavier ethers are conveyed to the organ of smell. According to the same
writer the accentuation of the flavour on dilution is due to the presence of
water decreasing the volatility of the acetate thereby masking its somewhat
pungent yet pleasant smell. These remarks apply exclusively to Jamaica rums,
and not to Demerara rums of less ether content ; in these Harrison"*9 claims
that the peculiarities are in some part due to the caramel compounds used in
colouring.

The origin of these ethers is connected with the process of manufacture
followed ; Allan31 considers that the factors are the presence of fission yeasts,
of butyric acid forming bacteria, of which he has isolated one, and of Bacillus
mesentericm, to which is attributed the presence of higher alcohols, especially
butyl alcohol ; Allan's work refers to Jamaica rums, and bacteria could play
only a very small part in the development of flavour in the quick fermentation
process followed in Demerara, where indeed bactericides are used to inhibit
their action.

That the budding yeasts have but little to do with the development of
flavour in rum is probable from the results of Peck and Deerr,5 who found in
pure culture that only 18 parts of ether (as acetate) were formed per 100,000
of alcohol, and previously Deerr had observed no special flavour when cultiva-
ting in pure culture fourteen Demerara yeasts ; with the fission yeast Peck and
Deerr isolated from Peruvian material no special flavour was observed ; from
Natal material they obtained, however, a Monilia, which produced a slow
alcoholic fermentation, and at the same time formed 7558 parts ethereal salts
(as acetate) per 100,000 of alcohol, both acetate and butyrate being present; to
this or to a similar organism they suggested the origin of ethers in high-class
rums. About the same time Ashby32 found a ' fruit ether producing yeast ' in
Jamaica distilleries. Micko27 by means of fractional distillation has established
the presence in Jamaica rum of a body which is not an aldehyde, ketone or
ester, but has the properties of an ethereal oil, though it may be allied to

526

FEHMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE.

the terpenes, and to this he attributes the peculiar flavour of Jamaica rum,
utilizing its absence and presence as diagnostic of the authenticity. Notwith-
standing, the presence of ethereal salts is a very large factor in forming the
flavour and bouquet of rums.

The sharp unpleasant taste of freshly distilled rums is probably due to
the presence of fatty acids ; these in time react with the alcohol forming
ethereal salts, an equilibrium between alcohol, fatty acid, ethereal salts and
water being formed ; to this is perhaps due the ageing of spirits.

It is stated that, in Jamaica, fruits such as mangoes, pine-apples, guavas, are
mixed with the wash so as to impart their flavour to the spirit, but of this the
writer has no first hand knowledge ; it has also been stated that old boots and
tobacco are used to flavour Jamaica rum, but this a gross miss-statement and
entirely without foundation.

The addition of laboratory prepared ethereal salts to silent spirits with
intent to imitate genuine rums is, of course, a fraud.

Various patents employing ozone, electricity, &c., with the idea of rapidly
ageing spirits have been taken out, but the writer is unaware of the successful
application of any one of them.

The Distillery. — A distillery consists of four separate buildings ;
the liquor loft containing the fermenting vats, the still house in which are
placed the stills, the engine house and the rum store ; to these in certain cases
may be added the boiler house.

The choice of position for the liquor loft is not unimportant, as experience
has shown that the fermentation is affected by apparently trivial causes ; it
should be raised on pillars about fifteen feet from the ground, be well lighted
and ventilated and open on all sides to the breeze, and should not be shadowed
by the other factory buildings. In certain factories the rum store is built
underneath the liquor loft ; this is inadvisable as besides running the risk of
wash leaking into the rum vats, circulation of air underneath the liquor loft
is prevented. The pipes and gutters used in connection with the distillery
should be placed and arranged so that they present easy access for cleaning;
underground pipes, and concrete or brickwork tanks in connection with a
distillery are unhesitatingly to be condemned.

The number of vats and their capacity depends on the amount of molasses
available and the time required for fermentation; every 100 gallons of
molasses will give between 600 and 700 gallons of wash at a density of 1'OGO,
and from every 100 tons of sugar made, from 3000 to 9000 gallons of
molasses result, dependent of course on the composition of the juice. Given
100 tons of sugar per week, from 3000 to 9000 gallons of wash per day will
be produced, and allowing the fomentation to take 48 hours, the capacity of
the vats must be double this ; in practice it would be advisable to allow at
least 25 per cent, in excess of the calculated figure. Of course in many places-

527

CANE SUGAR

a longer period than 48 hours is taken in the fermentation, and then a
corresponding increase in the capacity of the vats must be allowed. A usual
size of vat found in the West Indies is one holding about 3000 gallons ; in
Scotch and English distilleries much larger vats are the rule and a capacity of
50,000 gallons is not unusual ; the initial cost of erecting a few large vats, and
a loft to contain them and cost of upkeep, is less than for a larger number of
small vats, and it is a general opinion that a slightly better fermentation is
obtained in larger vats.

Antiseptics should find a larger use in distilleries, especially when shut
down ; all gutters, pipes, &c., should be carefully cleansed. The antiseptic
most in use in Europe now is a 1 per cent, solution of ammonium fluoride ; fresh

FIG. 278.

milk of lime is, however, an efficient cleanser and it will be found sufficient if
all vats and other places, which come in contact with sweets, be washed down
on ceasing operation with milk of lime.

Forms of Stills. — The stills used may be divided into two classes,
direct fired and steam stills, or again into intermittent or continuous stills.
Direct fired stills are very uncommon and only a few remain in unprogressive
districts ; they are constructed of copper and set in brickwork over a furnace
with a circular flue ; besides being expensive as regards first cost they are very
uneconomical in fuel consumption.

528

FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE.

Vat Still. — A sectional view of the general form of a steam-heated vat
still is given in Fig. 278; a is a wooden vat of capacity varying with the
amount of wash to be treated ; at d is shown the pipe through which the lees
are discharged when the wash is exhausted ; steam from the boilers is
admitted by the pipe b, which reaches nearly to the bottom of the vat ; on the
top of the vat is placed the copper goose neck c, which is continued into a
smaller vat e known as the retort ; in the latter are placed the low wines
resulting from the previous operation. At / is shown the rectifier ; this
consists of an upright cylindrical copper vessel in which are fixed a large

FIG. 279.

number of tubes of small diameter ; water is admitted to the rectifier by the
pipe g and circulates on the outside of these tubes ; from the rectifier a pipe
passes to the tank j in which a supply of cold water circulates, and after
passing in a serpentine fashion emerges at I and passes on to the spirit receiver.
The watery mixture of vapour and alcohol proceeds from the still to the retort
where it takes up any alcohol still remaining in the low wines, and pusses
upwards through the rectifier where a large portion of the water and other
bodies of high boiling point condenses and falls back into the retort ; the vapour

529

CANE SUGAR.

of alcohol leaves the retort at a temperature of from 180UF. to 190° F. and is
condensed in the serpentine in the tank j.

Column Still. — In Fig. 279 is given a semi-diagrammatic view of
what is known as the French column which is practically identical with
Coupler's still ; the column or dephlegmator a is divided into chambers by
plates, each of which has a central opening covered by a dome b ; a small
overflow pipe c passes from each plate to the next ; the vapours from the
boiler d pass upwards through the central openings through the layer of liquid
on each plate, and thence through the overflow pipes back to the boiler; the
vapours of high boiling point are condensed in the U pipes h in the condenser
/, passing back to the still by the pipes g ; a coil i is shown in the tank /
where the spirit is cooled.

Coffey Continuous Still. — The coffey still, Fig. 280, consists of
two parts, the analyser A, and the rectifier R; either column is built up of
rectangular wooden frames resting one on top of the other and the whole kept
in position by a number of vertical stay rods. The analyser is divided into a
number of chambers formed by the interposition of copper plates b t>} perforated
with a large number of holes about £ in. diameter ; in each plate is a disc valve
d d consisting of a disc of copper about 3 in. diameter and opening upwards ;
from each plate passes down a dip pipe cc about 9 in. long and 3 in. diameter ;
the top of the dip pipe projects about 1 in. above the copper plate and dips
into a cup which rests on the next lower plate. The rectifier is divided into
chambers by similar diaphragms, save that the five upper chambers are
separated from the others by an unperf orated copper sheet n n, which has a
large opening atp and a receptacle at o from which leads out a pipe m; the
opening at p has a collar 1 in. high ; the five upper plates have no valves or
perforations, their object being to cause vapour to pass in a serpentine-
direction.

The method of working is as follows : — Wash is pumped into an overhead
tank (not shown) and flows down the pipe a a ; this pipe is continuous, and
emerging at the bottom of the rectifier is carried to the top of the analyser and
discharges the wash over the top diaphragm ; the wash flows down the analyser
in a zig-zag direction passing down the dip pipes, which are placed as shown
at alternate ends of the plates ; reaching the bottom of the analyser the wash
discharges through the pipe Ic. Steam is admitted at a pressure of from 5 to
1 0 Ib. per square inch by the pipe * «', and passes upwards through the per-
forations in the plates ; the cups in which the dip pipes stand are always full
of wash, and acting as a seal prevent passage of vapour except through the
perforations ; the dip pipes projecting an inch above the diaphragms always
keep this depth of liquid on the plates ; in case the vapour is unable to pass

530

FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE.

FIG. 280.

531

CANE SUGAR.

quickly enough through the perforations, it can obtain a passage through the
valves dd\ the steam in its passage through the wash deprives it of its
alcohol, and a mixed vapour of alcohol, water and other volatile constituents
passes out of the analyser by the pipe //, and is led into the bottom of the
rectifier ; as the vapour meets the cold wash in the continuous pipe a a, it is
condensed and at the same time heats the wash ; the water vapour and bodies
of high boiling point, as well as some alcohol, are condensed in the lower part
of the still and fall dawn to the bottom and are continually taken away by the
pipe h, called the hot feints pipe. The alcohol in great part condenses in the
upper five chambers and falling down on the plate n n, is received in the
receptacle o and taken away by the pipe m ; this pipe leads to a refrigerator
and thence to the spirit store. A pipe g leads from the top of the rectifier
and takes away the uncondensed vapour ; this pipe too passes through a refri-
gerator, and the condensed vapours are collected and form the cold feints ; 1 1
is a water coil, by means of which the amount of cold feints allowed to be
formed can be regulated. The hot feints can either be allowed to mix with
the wash or they may be passed through a condenser and pumped to the top of
the analyser. The cold feints are collected separately, and when sufficient
have accumulated, they are mixed with the wash and redistilled ; if pumped
directly to the analyser, owing to their low boiling point they volatilize with
explosive violence.

The wash leaves the rectifier at a temperature of about 190° F. and is
completely exhausted of spirit in its passage down the diaphragms of the
analyser, the expelled vapour passing through the pipe //being at a tempera-
ture of about 205° F. to 210° F. The upper coil in the pipe a a is at the
temperature of the wash, and the temperature increases regularly on passing
down; the strength of spirit condensed in the upper five chambers can be
regulated by controlling the temperature. A high temperature causes alcohol
to pass off in the cold feint pipes, and at the same time diminishes the con-
densation of watery vapour so that a weak spirit results ; a low temperature
makes alcohol condense below the spirit plate, increasing the quantity of hot
feints. To obtain the best results the temperature of condensed spirit in the
spirit plate should lie between 176° F. and 180° F. The control of the still
is effected either by regulating the supply of wash or of steam ; valves are
iitted, of course, on both the wash pipe and steam pipe. To enable the
attendant to know the strength of the spirit at any moment, a small pipe
passing through a supplementary refrigerator takes a sample of spirit from
the spirit plate, and conducts it to a locked test case ; if spirit 45 O.P. is
required, three glass bubbles, one which floats in 42 O.P., one in 45 O.P. and
one in 48 O.P., are placed in the vessel receiving the spirit; as soon as all
three bubbles rise the attendant knows his spirit is too weak, and when two
sink that it is too strong. As a further guide thermometers are placed in

532

FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE.

Tarious parts of the still; one in the spirit plate, a second at about the
twelfth coil of the rectifier, and a third on the pipe carrying wash to the
analyser.

To use these stills to greatest advantage they must be worked with as
little sudden change as possible ; control is effected by regulating either the
flow of wash or steam ; in forms of stills where the wash is pumped to an
overhead tank, opening or shutting a cock or valve (the latter preferably)
controls the flow of wash. In other forms where the wash is pumped directly
through the coil a cock is fitted on the pipe, convenient to the distiller, and
connected to a second pipe leading back to the vessel from which the pump
draws. The amount of steam is regulated by a valve ; in general it is preferable
to control working by the flow of wash.

The spirit should not be run from the spirit plate too rapidly ; if the latter
be emptied by opening the cook too much, a weak spirit collects and the cock
must be closed until the test bubbles show that spirit of the correct strength
is forming. The supply of wash and steam must be adjusted to each other ;
too little steam imperfectly exhausts the wash and an excess results in too-
much watery vapour passing over, giving a weak spirit. To allow the distiller
to see that the wash is properly exhausted, vapour from the lees is collected in
a separator, and carried through the supplementary refrigerator to a test glass
in which are bubbles floating in water and spirit 98 U.P. ; should either of
these sink it is certain that the wash is imperfectly exhausted. The advantage
of these stills over the common type of vat still lies chiefly in their economy
of steam.

Approximate dimensions of a continuous still of the Coffey type working
up 1,000 gallons of wash per hour are here given, the letters referring to
sketch in Fig. 280. Rectifier R, total height 24 ft. x 8 ft. X 3 ft. ; analyser
A, total height 42 ft. X 8 ft. X 3 ft. ; number of chambers in both analyser
and rectifier 27; total length of pipe a a — contained in analyser — 416ft.;
diameter of pipe 2 in.; total surface of pipe 217 square feet; size of dip
pipes c in rectifier 4 in. X 9 in. ; and in analyser 1 3 in. x 3 in. ; diameter of
valves d, 5 in. ; diameter of vapour pipe/, 7 in. ; diameter of steam pipe «', 4 in. •
diameter of hot feints pipes h, 1^ in. ; diameter of spirit pipe, 1£ in. ; diameter
of cold feints pipe, 6 in. The still described is one constituted of wood and is
of rectangular section ; other forms of stills are built throughout of copper and
are often of circular section, the wash pipe being worm-shaped instead of
straight with U bends as in this case.

The advantage of the Coffey still lies in its economy of steam, the
in-coming wash condensing and being heated by the alcohol and water vapour
distilled ; actually it consumes only about one-third the steam required for a

533

CANE SUGAR.

discontinuous process. Its disadvantages lie in its removing from the pro-
duct bodies of boiling point remote from that of alcohol and to which the
flavour of rum is due ; attempts have been made to restrict the term rum to
the product of discontinuous stills.

Separation of Products of Fermentation. — When using the
old forms of vat stills the bodies that have low boiling point pass over in the first
runnings, while the fatty acids and higher alcohols having higher boiling points
pass over in the last runnings ; between these comes over the main body of
the distillate ; the first and last runnings are collected separately and are called
feints or low wines. In the continuous type of still the bodies of low
boiling point are found in the cold feints, the fatty acids in the hot feints ; a
complete separation is however impossible, and all these bodies are found in
greater or less degree in the spirit, dependent on the care exercised by the
distiller. The boiling points of the principal constituents of rum are in degrees
Fahrenheit: — Alcohol 173°; formic acid 216°; acetic acid 246°; butyric
acid 315°; capric acid 380°; ethyl formate 129°; ethyl acetate 168°; ethyl
butyrate 241° ; ethyl caprate 322°; formaldehyde 70°. It will be seen that
ethyl acetate and alcohol have nearly the same boiling point, so that any
•ethyl acetate present in the fermented wash will be totally recovered with
the rum ; the other bodies will be present in less quantity as their boiling
.point is more remote from that of alcohol ; the majority of these bodies
.are, however, volatile in steam and hence are present in the distillate in
larger quantity than would be supposed from their boiling point.

Caramel. — Caramel is the name given to the decomposition products
-obtained on heating sugar or glucose to temperatures in the neighbourhood
of 180°C. ; a black brittle amorphous highly hygroscopic substance, which
reduces Eehling's solution, results. This body is certainly a mixture of various
bodies, of the chemistry of which nothing is known. The product when pre-
pared from pure sugar or glucose, and when care is taken to prevent local
superheating, is highly soluble in water and to a less degree in spirit ; there
are present, however, especially when the decomposition is pushed to extremes,
caramels which are insoluble in water and soluble in spirit. If these are
present in any notable quantity, a perfectly clear 40 O.P. spirit may give a
deposit when mixed with water, and to the presence of these caramels is to be
attributed one of the causes of faultiness in rum.

Caramel produced by burning sugar is completely soluble in water in the
presence of alkalies, and the solution at the same time assumes a much darker
colour ; but caramels dissolved in spirit are precipitated by alkalies, the solution
becoming less coloured ; in the presence of alkalies the flavour of the caramel

534

FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE

undergoes a complete change, and at the same time gives off a peculiar
odour.

A process which was long kept a trade secret and used, it has been stated,
especially for colouring rums, consisted in burning sugar in the presence of
alkalies ; the proportions used were 60 parts of sugar and 2 parts of sodium
or I' 5 parts of caustic soda. This process is referred to as Asrymusry's; but in
view of what has been said above on the action of alkalies on caramel dissolved
in spirit, it would hardly promise success. The temperature at which the
conversion of sugar into caramel takes place has been stated by different
authorities as between 160° C. and 250° C.

When caramel is used for colouring rum, two points have to be considered;
the caramel should reduce the strength of the spirit as little as possible, and
give to the rum a sugary flavour. To obtain the latter effect the molasses or
sugar syrup should not be burned too far, but in this case the amount
of caramel required to give the necessary depth of colour so much increases
the density of the spirit that there is a large apparent loss.

The usual method of preparing caramel is as under : — Into an iron pot of
about 200 gallons' capacity, usually an old iron tayche, are introduced 40 to 50
gallons of molasses, and water added to a density of about 1'25; instead of
molasses a syrup of sugar and water of the same density is sometimes used. A
brick oven is built under the pot, and a brisk fire kept up ; the molasses or
syrup must be kept in continual motion, preferably by a mechanical stirrer.
The sugar solution rapidly darkens, and in from 60 to 90 minutes is quite
black. The usual test to show if the caramel is sufficiently burned is to remove
a portion on a stick, and after cooling, to break the caramel with the finger ; it
should be quite brittle. Another test is to drop a globule of the burnt caramel
into water, the floating of the globule being an indication that the caramel is
sufficiently burned; when either of these tests obtains, the caramel will
colour rum reasonably well, but to obtain a low obscuration the burning must be
continued longer. When the point at which the caramel is sufficiently burned
is decided, the fire is drawn and sufficient water added to permit of easy
carriage to the rum store.

The higher the temperature at which the caramel is burned, the less is
required to produce the necessary depth of colour, and the apparent loss of
strength is lower ; the after treatment in the rum store has also an effect on
the caramel. If the crude colour be repeatedly treated with strong 60 O.P. to
70 O.P. spirit, the colour solution allowed to settle, and the clear colour drawn
off, eventually a colour is obtained which gives a barely appreciable obscura-
tion ; this process is too lengthy to carry out in practice, but a colour burnt as
described above and treated once, bulk for bulk, with white rum from the still,

535

CANE SUGAR.

will give a fully coloured rum with apparent strength, as shown by the Sikes
hydrometer, only from one or two proof degrees less than the actual.

In the West Indies first molasses are generally used to prepare caramel,
and one gallon of molasses should afford material sufficient to colour from 50
to 60 gallons of rum.

It is sometimes found that a coloured rum obstinately refuses to settle ;
in this case the addition of about four ounces of alum per 1000 gallons of
spirits will often be found beneficial.

The essential part of the analysis of a caramel is the determination of its
colour intensity ; this determination is usually made by dissolving a fixed
weight of caramel in a definite volume of water or spirit and comparing the
colour with a standard prepared under similar conditions, or the colour may be
matched in terms of Lovibond's tintometer, which forms a very useful instru-
ment for this purpose. Determinations of the ash and reducing power are also
sometimes made ; a molasses caramel, of course, carries more ash than a sugar
caramel. The copper oxide reducing power varies considerably and generally
lies between -3 and *6, that of glucose being unit ; for highly burnt molasses
caramel the writer has found a reducing power of about '5. Connected
inversely with the colour intensity is the obscuration, caramel of high colour
intensity giving a low obscuration.

In the preparation of caramels for beers, porters and vinegars, a very well-
known trade formula is the addition of salts of ammonia, chiefly the carbonate
and chloride, in quantities of one to two pounds per 100 Ibs. of sugar or
glucose ; their addition is said to increase the colour intensity and to modify
the harsh bitter taste.

Various patented caramels are on the market ; these consist essentially of
organic dyes and are not caramels at all ; they colour rum with a low obscura-
tion but spoil the flavour and do not keep their colour permanently ; their use
is not to be recommended. Logwood extract has also been used as a source of
colour for rum.

The process described above gives a caramel suited for rums of about
40 O.P. ; for rums of proof strength the caramelization must not be carrried
so far.

Erlich33 by heating sugar in vacuo at 200° C. and extracting the product
with methyl alcohol and extracting or filtering the residue has obtained a
homogeneous body of composition C12H2201 j, 2H20; this body is stated to
be the most powerful caramel colour yet made.

Obscuration. — The obscuration of a spirit is the difference between
the actual proof strength and the apparent proof strength as determined by an

536

FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE.

immersion alcoholometer. Thus spirit showing 40-0 over proof by the alcohol-
ometer, and of actual strength 43 '1 over proof is said to have an obscuration
of 3'1 ; in some cases, however, the obscuration is expressed on the proof

O.-l

spirit, so that for the example quoted the obscuration is y7^j-:==2-17percent.
on proof spirit.

The easiest method of determining the obscuration is as under : —

1. Take the apparent strength by the hydrometer.

2. Evaporate about 200 c.c. of the spirit on a water bath till all the
alcohol is removed; take up the residue with water, and make up to the volume
of the spirit taken.

3. Take the density of the solution of the residue either by the pycno-
meter or by a hydrometer graduated to read -0001. It is absolutely essential
that all measurements be made at the temperature at which the instruments
are graduated.

Calculation : Let x •=. specific gravity of the obscured spirit, and d =

/*•

specific gravity of the residue dissolved in water; then —== original gravity of
the spirit.

Example: Coloured rum stands 21 0 Sikes at 84° F., indicating an
apparent strength of 40'6 O.P. ; the specific gravity corresponding to 21 Sikes
is -8512. The density of the residue dissolved in water is 1-0040. Then

,o t -I O

original gravity of spirit = , Q Q = -8478. The Sikes indication corresponding

to a specific gravity of -8478 is 19*0, indicating a spirit 42'8 O.P. ; hence the
obscuration is 42-8 — 40'6 — 2*2.

An older formula for use with this method gives x — d = original gravity
of the spirit.

A second method, and cne generally used for beers and wines, consists of
distillrng over the material until all the alcohol has passed over, rraking the
distillate up to the original volume and finding the strength of the distillate by
an immersion alcoholometer, which in the absence of solids in solution gives
exact results; with strong spirit, such as rum, it is extremely difficult,
if not impossible, to prevent loss by evaporation and the first method is
preferable.

In the following table are calculated obscurations from the observed
density of the residue dissolved in water, the standards adopted for the calcula-

537

CANE SUGAR.

tion being a spirit of strength 40-6 O.P. (=21 '0° Sikes) at a temperature of
84° F. ; the table is applicable to spirits varying considerably from these
adopted standards.

OBSCURATION TABLE.

Density
of Dissolved
Residue.

Obscuration.

Density
of Dissolved
Residue.

Obscuration.

Density
of Dissolved
Residue.

Obscuration.

1-0000

o-o

•0028

1-5

1-0054

2-9

1-0002

0-2

•0030

1-7

1-0056

3-0

1-0004

0-3

•0032

1-8

1-0058

3-1

1-0006

0'4

•0034

1-9

1-0060

3-1

•0008

0-5

•0036

2-0

1-0062

3-2

•0010

0-6

•0038

2-1

1-0064

3-3

•0012

0-7

•0040

2-2

1-0066

3-4

•0014

0-8

1-0042

2-3

1-0068

3-5

•0016

0-9

1-0044

2-4

1-0070

3-6

•0018

1-0

1 -0046

2-5

1 -0072

3-7

•0020

1-1

1-0048

2-6

1-0074

3-7

•0022

1-2

1-0050

2-7

1-0076

3-8

•0024

1-3

1-0052

2-8

1-0078

3-9

•0026

1-4

Alcoholometry. — Unfortunately iii England and her colonies alcohol
is measured in 'proof; a more annoying system could barely have been
devised ; by proof spirit is meant one which at 62° F. weighs -J-f- of an equal
bulk of water; 40 over proof (O.P.) means that 100 volumes of the spirit
contain as much alcohol as 140 volumes of proof; 40 under (U.P.) means that
140 volumes of the spirit contain as much alcohol as 100 volumes of proof;
absolute alcohol is 75*25 O.P., so that to convert volumes of proof spirit to
alcohol it is necessary to divide by 1'7525 and vice versa. Proof spirit contains
49-3 per cent, by weight, 57'06 per cent, by volume of alcohol. In France,
and also in Germany, the Gay Lussac scale is used ; this is the most rational
one and gives directly the percentage of alcohol by volume. The Cartier scale
is an empirical one, 43 being absolute alcohol and 22 being proof spirit. The
Beck scale is also an empirical one, 43'9 being absolute alcohol and 14-8 being
proof spirit. In the U.S.A. the Gendar scale is used ; 200 is absolute alcohol,
100 is U.S. proof (i.e., 50 per cent, by volume) and 0 is water.

The bubbles used in distilleries as a guide in the test case are based on
the Cartier scale; they are numbered from 16 to 30 ; bubble 25 corresponds
with 25 Cartier, but bubble 26 corresponds to 24 Cartier, &c.

538

FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE.

COMPARISON OF

THE DIFFERENT ALCOHOL SCALES.

Alcohol

per cent,
by Volume.

Proof.

Cartier.

Beck.

Gendar.

Bubble.

100 ...

75-25 O.P.

.. 45

44

200

—

95 ...

66-4

.. 40

.. 38

190

—

90 ..

57'6

36-5

34

180

—

85 .. •

48-9

. . 33-5

.. 30

.. 170

17

80

40-1

.. 31

.. 27

.. 160

19

75 ..

31'4

.. 29

.. 24

150

21

70 ..

22-7

. . 27

21

140

.. 23

65 ..

13-9

25

.. 18

.. 130

25

60

5-2

. . 23

.. 16

.. 120

.. 27

55 ..

3-6 U.P.

.. 21

.. 14

110

.. 29

50 .1

12-4

20

12

100

.. 30

45 ',..

21-1

19

-.. 10

90

—

40 ,.

29-9

.. 17-5

9

80

—

35 .,

38-7

16-5

.. • 7

70

30 ..

47'5

15-5

6

60

—

25 . .

56-1

.. 15

5

50

—

20 ..

64-9

14

4

40

—

15

73-7

. . 13-5

3

30

—

10

82-5

.. 13

2

20

—

5 ..

91-2

.. 12

1

10

—

0 ..

0

.. 11

0

0

Control of the Distillery.* — In all molasses distilleries with
which the writer is acquainted the control is limited to the revenue require-
ments supplemented occasionally by determinations of the reducing sugars in
the wash ; a record is in this last case obtained of the amount of sugar required
to produce a unit of alcohol. This forms a very imperfect control and a ten-
tative more complete scheme is outlined below.

Fermentation Control. — A composite sample of the wash is collected and
in this sample are determined the reducing sugars after inversion expressed as
invert sugar ; a second sample is fermented with a pure culture of an approved
•distillery yeast and in the fermented sample are determined the alcohol and
the unfermentable sugars; • deducting the unfermentable sugars from those
originally found gives the amount of fermentable sugars originally present :
this quantity should be used in calculating the yield of alcohol per pound of
sugar.

The results obtained on the small scale with pure culture should be com-
pared with those found on the commercial scale and the deficiency indicates
the loss of alcohol due to imperfections in the process of fermentation.

Distillation Control. — The alcohol in the wash as it enters the still forms
the basis of this control; it should be determined in a composite sample, and

* I purposely do not touch on the biological control ; this subject is so specialized that
it is out of place here and cannot be satisfactorily treated save in a special work; in the
Bibliography I give titles of some books dealing with fermentation ; reference should be
made to these.— N. D.

539

CANE SUGAR.

compared with the amount actually recovered ; the balance is to be found in
the feints in the lees and in leaks from the still; the alcohol in these residues
should also be determined and all expressed as percentages of that originally
present ; finally an account of the alcohol produced per unit of total and of
fermentable sugar should be made out.

Amount of Alcohol obtainable from Molasses.— Fermen-
tation proceeds roughly under the equation

C6H1206 = 2C2H5OH -f 2C02
Glucose Alcohol Carbon dioxide.

Following on this equation 1 Ib. of glucose or *95 Ib. of cane sugar could
afford -51 lib. of alcohol and -489 Ib. carbon dioxide; this yield is never
obtained in practice even when the distillation losses are disregarded. Peck
and Deerr5 fermented in pure culture a number of molasses with tropical yeasts
and found that on an average 90 per cent, of the fermentable sugars were
recovered in alcohol, the amount as indicated from the above equation being
put equal to 100. In addition, in Hawaiian molasses they found from 4 '05
per cent, to 7 '32 per cent, of the sugars were unfermentable ; previously
in Egyptian molasses Pellet had observed 2 '40 per cent, of 'glutose*
and Deerr had found up to 3 per cent, in Demerara molasses. The total
amount of sugars in cane molasses varies from 45 per cent, to 65 per cent, so
that it is impossible in the absence of an analysis to state what quantity of
alcohol can be obtained from a molasses.

Analyses. — The analyses necessary to a distillery control are indicated
briefly below.

Density of Wash. — The methods given for juices in Chapter XXIV. are
applicable.

Attenuation. — The attenuation is the difference between the initial and
final density, water being put equal to 1000 ; thus wash initially at 1063 and
finally at 1015 is said to have attenuated 48 degrees. For each degree of
attenuation it is customary to assume the presence of so much proof spirit ;
a common allowance is 1 per cent, of proof spirit for every 5 degrees of attenua-
tion. As the result of a series of laboratory fermentations with pure cultures,
the writer found 1*17 per cent, of proof spirit for every 5 degrees of attenua-
tion. This method is not meant as an accurate determination of percentage of
proof spirit, but as a guide to revenue and customs authorities.

Sugars. — There is no necessity to determine the cane sugars as such ; the
sugars should be determined after inversion following the methods given in
Chapter XXIII. ; as the sugars will be mainly dextrose and levulose in approxi-
mately equal proportions, it will be best to calculate them as invert sugar.

540

FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE.

Alcohol in Wash and Lees. — Take a definite quantity of material,
neutralize with caustic soda, and distil until about 90 per cent, of the original
volume has been collected ; make up with water to original volume and
determine the density of the distillate by means of a pycnometer, whence the
percentage of alcohol is obtained by reference to the table given below. As
lees usually contains very little alcohol it will be well to take a large quantity,
say 1000 c.c., distil over 500 c.c., redistil the distillate until 250 c.c. have
come over, and finally determine the density of this portion; otherwise the
density of the distillate differs so little from unity that a large percentage
error may arise.

Alternatively the fractionating still heads of large cooling area, listed by
dealers in apparatus, may be used to obtain the alcohol concentrated in a
distillate of small volume.

A form of pycnometer which is of great use in the tropics is that due to
Boot, where the bottle containing the liquid is enclosed in a second, the space
between them being evacuated; liquids may be cooled down to 15° C. and
kept in the inner bottle without change of temperature and without the con-
densation of water on the outside of the bottle.

The table connecting density and percentage of alcohol given below is
referred to water at 60° F. ; in the tropics materials must be cooled down to
near this temperature ; in the absence of ice this is best done by dissolving in
water a salt such as thiosulphate of soda. Small variations from the standard
temperature may be corrected by the use of the expression :

where D is the required density, D' the observed density, d the difference in
temperature in centigrade degrees between 15'5° C. (60° F.) and that at which
the observation was made.

A table connecting degree Sikes and specific gravity at 84° F. for strong
spirits is added as being useful in certain districts.

REFERENCES IN CHAPTER XXV.r.

1 . Die Hefepilze.

2. Perrault. Le Rhum.

3. Bull. Sot. Dept. Jamaica., May, Aug., Sept., 1895; Jan., 1896.

4. Wochenschrift fur Brauerei, 1887, No. 44.

5. Bull. 28 Agric. H.S.P.A.

6. Arch. 1894, 529.

541

CANE SUGAR.

7. Bull. Assoc. XXIII., 639.

8. Eng. Patent, 23779 of 1902.

9. Mainly after Klocker's Fermentation Organisms.

10. Jour. Soc. Chem. Ind., 1898, 535.

11. Proc. Lin. Soc., N.S.W., XXVL, 684.

12. Proc. Lin. Soc., N.S.W., XXVL, 589.

13. Bull. 9, Path. H.S.P.A.

14. W. I. B., VI. , 386.

15. Jour. Am. Chem. Soc. 19, 238.

16. 8. C., 289

17. /. 8. J., 126.

18. The Micro-organism of Faulty Rum, Oxford, 1897.

19. 8. 0., 349; /. 8. J., 2.

20. Proc. Lin. Soc., N.S.W., XXV., 594; /. 8. J., 44 and 45,

21. Bull. 21, Agric. H.S.P.A.

22. W. I. B., VII., 226.

23. Louisiana Planter, XXXIV., 237.

24. From Lafar's Technical Mycology, Vol. V.

25. W. I. B., VII., 141.

26. Timehri., 1890, 90.

27. /. 8. J., 125, 128, 129.

28. Arch. 1905, 379.

29. British Guiana Official Gazette, Oct. 19, 1904.

30. W. I. B., VIL, 120.

31. W. I. B., VIL, 141.

32. /. 8. J., 126.

33. Int. Cong. Applied Chem., 1909.

542

FERMENTATION WITH SPECIAL REFERENCE TO THE SUGAR HOUSE.

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543

CANE SUGAR.

DEGREE SIKES AND SPECIFIC GRAVITY AT 81° F.

0

•1

•2

•3

•4

•5

•6

•7

•8

•9

•8458
•8476

17
18

•8443
•8460

•8444
•8462

•8446
•8464

•8448
•8465

•8450
•8467

•8452
•8469

•8453
•8411

•8455
•8472

•8457
•8474

19

•8478

•8179

•8481

•8483

•8485

•8487

•8488

•8490

•8492

•8493

120

•8495

•8497

•8498

•8500

•8502

•8503

•8505

•8507

•8509

•8510

21

•8512

•8514

•8516

•8518

•8519

•8521

•8523

•8524

•8526

•8528

•)•)

•8530

•8531

•8533

•8535

•8537

•8538

•8540

•8542

•8544

•8546

544

APPENDIX

TABLES

ADDITIONAL NOTES EELATING TO CERTAIN PORTIONS
OF THE TEXT.

545

35

APPENDIX. )

PKOPERTIES OF SATURATED STEAM.

(After Peabody.)

ENGLISH UNITS.

Temperature
degrees
Fahrenheit.

Pressure Ibs.
per
square inch.

Heat of the
Liquid.

Heat of
Vaporization.

Specific Volume
cubic feet
per pound.

32

0-0886

o-o

1071-7

3308

33

0-0923

I'O

1071-2

3179

34

0-0960

2-0

1070-7

3062

35

0-0999

3-0

1070-2

2950

36

0-1010

4-0

1069-7

2842

37

0-1082

5-0

1069-2

2737

38

0-1126

6-1

1068-7

2634

39

0-1171

7-1

1068-2

2538

40

0-1217

8-1

1067-6

2446

41

0-1265

9-1

1067-1

2358

42

0-1315

10-1

1066-6

2272

43

0-1367

11-1

1066-0

2190

44

0-1421

12-1

1065-5

2110

45

0-1476

13-1

1065-0

2035

46

0-1533

14-1

1064-4

1963

47

0-1591

15-1

1063-9

1894

48

0-1652

16-1

1063-4

1828

49

0-1715

17-1

1062-8

1764

50

0-1780

18-1

1062-3

1703

51

0-1848

19-1

1061-8

1643

52

0-1918

20-1

1061-3

1586

53

0-1990

21-1

1060-7

1531

54

0-2064

22-1

1060-2

1479

55

0-2140

23-1

1059-7

1429

56

0-2219

24-1

1059-1

1381

57

0-2301

25-1

1058-6

1335

58

0-2385

26-1

1058-1

1291

59

0-2471

27-1

1057-6

124$

60

0-2561

28-1

1057-0

1207

61

0-2654

29-1

1056-5

1167

62

0-2750

30-1

1056-0

112&

63

0-2848

31-1

1055'5

1091

64

0-2949

32-1

1055-0

1056

65

0-3054

33-1

1054-4

1021

66

0-3161

34-1

1053-9

988

67

0-3272

35-1

1053-4

956

68

0-3386

36-1

1052-8

925

547

CANE SUGAR.

PROPERTIES OF SATURATED STEAM.— Continued.

ENGLISH UNITS.

Temperature
degrees
^Fahrenheit.

Pressure Ibs.
pei-
square inch.

Heat of the
Liquid.

Heat of
Vaporization.

Specific Volume,
cubic feet
per pound.

69

0-3505

37-1

1052-3

896

70

0-3627

38-

1051-8

868

71

0-3752

39-

1051-2

840

72

0-3879

40'

1050-7

813

73

0-4012

41-

1050-2

788

74

0-4149

42-

1049-7

763

75

0-4289

43-

1049-2

739

76

0-4434

44-

1048-7

717

77

0-4582

45-

1048-1

695

78

0-4736

46-

1047-6

674

79

0-4894

47-

1047-1

654

80

0-5056

48-

1046-5

634

81

0-5223

49-

1046-0

615

82

0-5395

50'

1045-4

596

83

84

0-5572
0-5754

61-

52-

1044-9
1044-4

578
561

85

0-5942

53-

1043-9

544

86

0-6134

54-1

1043-3

528

87

0-6332

55-1

1042-8

513

88

0-6535

56-1

1042-3

498-0

89

0-6745

57-1

1041-7

483-4

90

0-6960

58-1

1041-2

469-2

91

0-7181

59-1

1040-6

455-4

92

0-7408

60-1

1040-1

442-0

93

0-7642

61-1

1039-5

429-1

94

0-7882

62-1

1039-0

416-7

95

0-8128

63-1

1038-5

404-8

96

0-8381

64-1

1037-9

393-3

97

0-8640

65-0

1037-4

382-1

98

0-8907

66-0

1036-8

371-3

99

0-9180

67-0

1036-3

360-9

100

0-9461

68-0

1035-7

350-8

101

0-9751

69-0

1035-1

341-1

102

1-0047

70-0

1034-6

331-6

103

1-0351

71-0

1034-0

322-4

104

1-0663

72-0

1033-5

313-5

105

1-098

73-0

1032-9

304-8

106

1-131

74-0

1032-4

296-4

107

1-165

75-0

1031-8

288-2

108

1-200

76-0

1031-2

280-2

109

1-235

77-0

1030-7

272-6

110

1-271

78-0

1030-1

265-2

548

APPENDIX.

PROPERTIES OF SATURATED STEAM.— Continued.

ENGLISH UNITS.

Temperature
degrees
Fahrenheit.

Pressure Ibs.
per
square inch.

Heat of the
Liquid.

Heat of
Vaporization.

Specific Volume
cubic feet
per pound.

Ill

1-308

79-0

1029-6

258-0

112

1-347

80-0

1029-0

251-1

113

1-386

81-0

1028-4

244-4

114

1-426

82-0

1027-8

238-0

115

1-467

83-0

1027-2

231-8

116

1-509

84-0

1026-7

225-7

117

1-552

85-0

1026-1

219-8

118

1-597

86-0

1025-5

214-0

119

1-642

87-0

1025-0

208-4

120

1-689

88-0

1024-4

203-0

121

1-737

89-0

1023-8

197-8

122

1-785

90-0

1023-2

192-7

123

1-835

91-0

1022-7

187-7

124

1-886

92-0

1022-1

182-9

125

1-938

93-0

1021-5

178-3

126

1-992

94-0

1021-0

173-8

127

2-047

95-0

1020-4

169-4

128

2-103

96-0

1019-8

165-2

129

2-161

97-0

1019-3

161-1

130

2-220

98-0

1018-7

157-1

131

2-280

99-0

1018-1

153-2

132

2-441

100-0

1017-6

149-5

133

2-403

101-0

1017-0

145-8

134

2-467

102-0

1016-5

142-2

135

2-533

103-0

1015-9

138-8

136

2-600

104-0

1015-4

135-4

137

2-669

105-0

1014-8

132-1

138

2-740

106-0

1014-2

128-9

139

2-812

107-0

1013-6

125-8

140

2-885

108-0

1013-1

122-8

141

2-960

109-0

1012-5

1199

142

3-037

110-0

1011-9

117-1

143

3-116

111-0

1011-4

114-3

144

3-196

112-0

1010-8

111-6

145

3-278

113-0

1010-2

109-0

146

3-361

114-0

1009-6

106-5

147

3-447

115-0

1009-0

104-0

148

3-535

116-0

1008-4

101-6

149

3-624

117-0

1007-8

99-2

150

3-715

118-0

1007-2

96-9

151

3-808

119-0

1006-7

94-7

152

3-903

120-0

1006-1

92-5

549

CANE SUGAR.

PROPERTIES OF SATURATED STEAM.—
ENGLISH UNITS.

Temperature
degrees
Fahrenheit.

Pressure Ibs.
pei-
square inch.

Heat of the
Liquid.

Heat of
Vaporization.

Specific Volume
cubic feet
per pound.

153

4-000

121-0

1005-5

^90-4

154

4-099

122-0

1004-9

88-4

155

4-200

123-0

1004-3

86-4

156

4-303

124-0

.1003-7

84-5

157

4-409^

125-0

1003-1

82-6

158

4-517

126-0

1002-5

80-7

159

4-626

127-0

1002-0

78-9

160

4-738

128-0

1001-4

77-2

' *61

4-852

129-0

1000-8

75-4

162

4-969

130-0

1000-2

73-7

163

5-088

131-0

999-6

72-1

164

5-210

132-0

999-0

70-6

165

5-334

133-0

998-4

69-1

166

5-460

134-0

997-9

67'7

167

5-589

135-0

997-3

66-2

168

5-720

136-0

996-7

64-8

169

5-853

137-0

996-1

63-4

170

5-990

138-0

995-5

62-0

171

6-129

139-0

994-9

60-6

ri72

6-270

140-0

994-3

59-3

173

6-415

141 0

993-7

58-1

174

6-563

142-0

993-1

56-9

175

6-714

143-0

992-5

55-7

176

6-868

144-0

991-9

54-5

17*

7-025

145-0

991-3

53-4

178

7-185

146-0

990-7

52-3

^179

7-346

147-0

990-1

52-2

180

7-510

148-0

989-5

50-2

isi

7-678

149'0

988-9

49-13

- 1&2

7-849

150-1

988-3

48-11

< 183

8-024

151-

987-7

47-12

184

8-202

152-

987-1

46-17

' 185

8-383

153-

986-5

45-23

186

8-568

154-

985-9

44-33

187

$•756

155-

985-3

43-45

18$

8-947

156-

984-7

42-59

f 189

9-141

157-

984-0

41-75

190

9-339

158-1

983-4

40-92

191

9-541

159-1

982-8

40-11

192

9-746

160-1

982-2

39-31

193

9-955

161-1

981-5

38-53

194

10-168

162-1

980-9

37-77

550

PROPERTIES - OF SATURATED STEAM. ^Continued.

ENGLISH UNITS.

Temperature
degrees
Fahrenheit.

Pressure Itos.
per
square inch.

Heat of the
Liquid.

Heat of
Vaporization.

Specific Volume
cubic feet
per pound.

195

10-385

163-1

980-3

"37-03

196

10-605

164-1

979-7

36-31

197

10-830

165-1

979-1

35-61

198

11-059

166-2

978-4

34-93

1^9

ir-29i

167-2

977'8

34-27

200

11-528

168-2 :

977-2

33-62

201

11-768

169-2

976-6

32-99

202

12-013

170-2

976-0

32-37

203

12-261

171-2

975-4

'31-75

204"

12-514

172-2

974-7

31-15

205

12-771

173-2

974-1

30-56

206

13-033

174-2

973-5

29-98

207

13-299

175-2

972-8

29-41

208

13-570

176-2

972-2

28-86

209

13-845

177-2

971-6

28-32

210

14*125

178-3

970-9

27-80

211

14-409

179-3

970-3

27-29

212

14-698

180-3

969-7

26-78

213

14-992

181-3

969-1

26-29

214

15-291

182-3

968-5

25-81

215

15-595

183-3

967-8

25-34

216

15-903

184-3

967-2

24-88

217

16-217

185-3

966-5

24-43

218

16-536

186-3

965-9

23-99

219

16-859

187-4

965-2

23-56

220

17-188

188-4

964-6

-23-14

221

17-523

189-4

964-0

22-75

222^

17-863

190-4

963-3

22-33

223

18-208

191-4

962-7

21-93

224

18-558

192-4

962-0

21-54

225

18-914

193-4

961-4

21-16

226

19-275

194-4

960-7

;20-78

227

19-643

195-4

960-1

20-42

228

20-02

196-5

959-4

20-07

229

20-40

197-5

958-7

19-72

230

20-78

198-5

958-1

19-37

231

21-17

199-5

957-4

19-04

232

21-57

200-5

956-8

18-71

233

21-97

201-5

956-1

18-39

234

22-38

202-5

955-4

18-08

235

22-79

203-6

954-8

17-77

236

23-21

204-6

954-1

17-46

551

CANE SUGAE.

PROPERTIES OF SATURATED STEAM.— Continued.

ENGLISH UNITS.

Temperature
degrees
Fahrenheit.

Pressure Ibs.
pei-
square inch.

Heat of the
Liquid.

Heat of
Vaporization.

Specific Volume
cubic feet
per pound.

237

23-64

205-6

953-4

17-16

238

24-08

206-6

952-8

16-87

239

24-52

207-6

952-1

16-59

240

24-97

208-6

951-4

16-31

241

25-42

209-6

950-8

16-04

242

25-88

210-7

950-1

15-77

243

26-35

211-7

949-4

15-51

244

26-83

212-7

948-7

15-26

245

27-31

213-7

948-1

15-01

246

27-80

214-7

917-4

14-77

247

28-29

215-7

946-7

14-52

248

28-79

216-7

946-0

14-28

249

29-30

217-7

945-4

14-05

250

29-82

218-8

944-7

13-82

251

30-35

219-8

944-0

13-59

252

30-88

220-8

943-3

13-37

253

31-42

221-8

942-6

13-16

254

31-97

222-8

941-9

12-94

255

32-53

223-8

941-2

12-73

256

33-09

224-9

940-5

12-53

257

33-66

225-9

939-8

12-33

258

34-24

226-9

939-1

12-13

259

34-83

227-9

938-4

11-94

260

35-42

229-0

937-8

11-75

261

36-02

230-0

937-1

11-57

262

36-64

231-0

936-4

11-39

263

37-26

232-0

935-7

11-21

264

37-89

233-0

935-0

11-04

265

38-53

234-0

934-3

10-87

266

39-17

235-0

933-6

10-70

267

39-83

236-1

932-9

10-53

268

40-49

237-1

932-1

10-37

269

41-16

238-1

931-4

10-21

270

41-84

239-1

930-7

10-05

271

42-54

240-2

930-0

9-901

272

43-24

241-2

929-3

9-749

273

43-95

242-2

928-6

9-599

274

44-67

243-2

927-9

9-453

275

45-39

244-2

927-2

9-309

275-8

46-

245-1

926-6

9-195

277-16

47-

246-4

925-6

9-012

278-47

48-

247-8

924-7

8-838

552

APPENDIX.

PROPERTIES OF SATURATED STEAM.— Continued.

ENGLISH UNITS.

Temperature
degrees
Fahrenheit.

Pressure Ibs.
pel-
square inch.

Heat of the
Liquid.

Heat of
Vaporization.

Specific Volume
cubic feet
per pound.

279-76

49-

249-1

923-8

8-670

281-03

50-

250-4

922-8

8-507

282-28

51-

251-7

921-9

8-350

283-52

52-

253-0

921-0

8-198

284-74

53'

254-2

920-1

8-052

285-93

54-

255-4

919-3

7-912

287-09

55-

256-6

918-4

7-778

288-25

56'

257-8

917-6

7-647

289-40

57'

259-0

916-7

7-519

290-53

58'

260-1

915-9

7-397

291-64

59-

261-3

915-1

7-280

292-74

60-

262-4

914-3

7-166

293-82

61-

263-5

913-5

7-055

294-88

62-

264-6

912-7

6-949

295-93

63-

265-7

911-9

6-846

296-97

64-

266-7

911-1

6-745

298-00

65-

267-8

910-4

6-647

299-02

66-

268-8

909-6

6-552

300-02

67-

269-8

908-9

6-460

301-01

68-

270-9

908-1

6-370

301-99

69-

271'9

907-4

6-283

302-96

70-

272-9

906-6

6-199

303-91

TV

273-8

905-9

6-117

304-86

72-

274-8

905-2

6036

305-79

73-

275-8

904-5

5-958

306-72

74-

276-7

903-8 5-882

307-64

75-

277-7

903-1

5-807

308-54

76-

278-6

902-4

5-735

309-44

77-

279-5

901-8

5-665

310-33

78-

280-4

901-1

5-597

311-21

79-

281-3

900-4

5-530

312-08

80-

282-2

899-8

5-466

312-94

81-

283-1

899-1

5-403

313-79

82-

283-9

898-5

5-342

314-63

83-

284-8

897-8

5-281

315-47

84-

285-7

897-2

5-220

316-30

85-

286-5

896-6

5-161

317-12

86-

287-4

895-9

5-104

317-93

87'

288-2

895-3

5-048

318-73

88-

289-0

894-7

4-993

319-53

89-

289-9

894-1 4-939

320-32

90-

290-7

893-5 4-886

553

CANE SUGAR.

PROPERTIES OF SATURATED STEAM. — Continued.

ENGLISH UNITS.

Temperature
degrees
Fahrenheit.

Pressure Ibs.
per
square inch.

Heat of the
Liquid.

Heat of
Vaporization.

Specific Volume
cubic feet
per pound.

321-10

91-

291-5

892-9

4-835

321-88

92-

292-3

892-3

4-785

322-65

93-

293-1

891-7

4-736

323-41

94-

293-9

891-1

4-689

324-16

95-

294-6

890-5

4-644

324-91

96-

295-4

889-9

4-599

325-66

97-

296-2

889-3

4-556

326-40

98-

296-9

888-7

4-514

327-13

99-

297-7

888-2

4-473

327-86

100-

298-5

887-6

4-432

328-58

101-

299-2

887-0

4-391

329-30

102-

299-9

886-5

4-351

330-01

103-

300-6

885-9

4-311

330-72

104-

301-4

885-3

4-272

381-42

105-

302-1

884-8

4-233

332-11

106-

302-8

884-3

4-195

332-79

107-

303-5

883-7

4-157

333-48

108-

304-2

883-2

4-120

334-16

109-

304-9

882-6

4-083

334-83

llO-

305-6

882-1

4-047

335-50

lll-

306-3

881-6

4-011

336-17

112-

307-0

881-0

3-976

336-83

113-

307-7

880-5

3-943

337*48

114-

308-3

880-0

3-909

338-14

115-

309-0

879-5

3-876

338-78

lie-

309-7

879-0

3-844

339-42

in-

310-3

878-5

3-812

340-06

ii8-

311-0

878-0

3-781

340-69

119-

311-7

877-4

3-752

341-31

120'

312-3

876-9

3-723

341-94

121-

312-9

876-4

3-694

342-56
343-18

122-
123-

313-6
314-2

875-9

875-4

3-665
3-637

343-79

124-

314-8

875-0

3-609

344-39

125-

315-5

874-5

3-581

345-00

126-

316-1

874-0

3-554

345-60

127-

316-7

873-5

3-527

346-20

128-

317-3

873-0

3-501

346-79

129-

317-9

872-6

3-476

347-38

130-

318-6

872-1

3-451

554

APPENDIX.

CORRESPONDENCE BETWEEN BRIX AND SPECIFIC GRAVITY.

17'5°0.
17-5°C.

%*

Brg

s«

•0

•1

•2

•3

•4

•5

•6

•7

•8

•9

0

1-00000

1-00038

1-00077

1-00116

1-00155

•00193

1-00232

•00271

1-00310

1-00349

1

1-00388

1-00427

1-00466

1-00505

1-00544

•00583

1-00622

-00662

1-00701

1-00740

2

1-00779

1-00818

1-00858

1-00897

1-00936

•00976

1-01015

•01055

1-01094

1-01134

3

1-01173

1-01213

1-01252

1-01292

1-01332

•01371 .

1-01411

•01451

1-01491

1-01531

4

1-01570

1-01610

1-01650

1-01690

1-01730

•01770

1-01810

•01850

1-01890

1-01930

5

1-01970

•02010

1-02051

1-02091

1-02131

•02171

1-02211

•02252

1-02292

1-02333

6

1-02373

•02413

1-02454

1-02494

1-02535

•02575

1-02616

•02657

1-02697

1-02738

7

1-02779

•02819

1-02860

1-02901

1-02942

•02983

1-03024

1-03064

1-03105

1-03146

.

8

1-03187

•03228

1-03270

1-03311

1-03352

•03393

1-03434

1-03475

1-03517

1-03558

9

1-03599

•03640

1-03682

1-03723

1-03765

•03806

1-03848

•03889

1-03931

1-03972

10

1-04014

•04055

1-04097

1-04139

1-04180

•04222

1-04264

•04306

1-04348

1-04390

11

1-04431

•04473

1-04515

1-04557

1-04599

•04641

1-04683

•04726

1-04768

1-04810

12

1-04852

•04894

1-04937

1-04979

1-05021

•05064

1-05106

•05149

1-05191

1-05233

13

1-05276

•05318

1-05361

1-05404

1-05446

•05489

1-05532

•05574

1-05617

1-05660

14

1.05703

•05746

1-05789

1-05831

1-05874

•05917

1-05960

1-06003

1-06047

1-06090

15

1-06133

1-06176

1-06219

1-06262

1-06306

1-06349

1-06392

1-06436

1-06479

1-06522

16

1-06566

1-06609

1-06653

1-06696

1-06740

1-06783

1-06827

1-06871

1-06914

1-06958

17

1-07002

1-07046

1-07090

1-07133

1-07177

1-07221

1-07265

1-07309

1-07358

1-07397

18

1-07441

1-07485

1-07530

1-07574

1-07618

1-07662

1-07706

1-07751

1-07795

1-07839

19

1-07884

1-07928

1-07973

1-08017

1-08062

1-08106

1-08151

1-08196

1-08240

1-08285

20

1-08329

1-08374

1-08419

1-08464

1-08509

1 08553

1-08599

1-08643

1-08688

1-08733

21

1-08778

1-08824

1-08869

1-08914

1-08959

1-09004

1-09049

1-09095

1-09140

1-09185

22

1-09231

1-09276

1-09321

1-09367

1-09412

1-09458

1-09503

1-09549

1-09595

1-09640

23

1-09686

•09732

1-09777

1-09823

1-09869

1-09915

1-09961

1-10007

1-10053

1-10099

24

1-10145

•10191

1-10237

1-10283

1-10329

1-10375

1-10421

1-10468

1-10514

1-10566

25

1-10607

•10653

1-10700

1-10746

1-10793

1-10839

1-10885

1-10932

1-10979

1-11026

26

1-11072

•11119

1-11166

•11213

1-11259

1-11306

•11353

1-11400

1-11447

1-11494

27

1-11541

•11588

1-11635

•11682

1-11729

1-11776

•11824

1-11871

1-11918

1-11965

28

1-12013

1-12060

1-12107

•12155

1-12202

1-12250

•12297

1-12345

1-12393

1-12440

29

1-12488

1-12536

1-12583

•12631

1-12679

1-12727

•12775

1-12823

1-12871

1-12919

30

1-12967

1-13015

1-13063

•13111

1-13159

1-13207

•13255

1-13304

1-13352

1-13400

31

1-13449

1-13497

1-13545

•13594

1-13642

1-13691

•13740

1-13788

1-13837

1-13885

32

1-13934

1-13983

1-14032

•14081

1-14129

1-14178

•14227

1-14276

1-14325

1-14374

33

1-14423

1-14472

1-14521

•14570

1-14620

1-14669

•14718

1-14767

1-14817

1-14866

34

1-14915

1-14965

1-15014

•15064

1-15113

1-15163

•15213

1-15262

1-15312

1-15362

35

1-15411

1-15461

1-15511

•15561

1-15611

1-15661

•15710

1-15760

1-15810

1-15861

36

1-15911

1-15961

1-16011

•16061

1-16111

1-16162

•16212

1-16262

1-16313

1-16363

37

1-16413

1 16464

1-16514

•16565

1-16616

1-16666

•16717

1-16768

1-16818

1-16869

38

1-16920

2-16971

1-17022

•17072

1-17123

1-17174

•17225

1-17276

1-17327

1-17379

555

CANE SUGAR.

17-5CC.

CORRESPONDENCE BETWEEN Buix AND SPECIFIC GRAVITY. .- ,..,.• — Continued

17"o U.

E

<U £

&Z

<§«

•0

•1

•2

•3

•4

•5

•6

•7

•8

•9

39

1-17430

•17481

1-17532

1-17583

1-17635

1-17686

1-17737

1-17789

1-17840

1-17892

40

1-17943

•17995

1-18046

1-18098

1-18150

1-18201

1-18253

1-18305

1-08357

1-18408

41

1-18460

•18512

1-18564

1-18616

1-18668

1-18720

1-18772

1-18824

1-18877

1-18929

42

1-18981

•19033

1-19086

1-19138

1-19190

1-19243

1-19295

1-19348

1-19400

1-19453

43

1-19505

•19558

1-19611

1-19663

1-19716

1-19769

1-19822

1-19875

1-19927

1-19980

44

1-20033

•20086

1-20139

1-20192

1-20245

1-20299

1-20352

1-20405

1-20458

1-20512

45

•20565

•20618

1-20672

1-20725

1-20779

1-20832

1-20886

1-20939

1-20993

1-21046

46

•21100

•21154

1-21208

1-21261

1-21315

1-21369

1-21423

1-21477

1-21531

1-21585

47

•21639

•21693

1-21747

1-21802

1-21856

1-21910

1-21964

1-22019

1-22073

1-22127

48

•22182

•22236

1-22291

1-25345

1-22400

1-22455

1-22509

1-22564

1-22619

1-22673

49

•22728

•22783

1-22838

1-22893

1-22948

1-23003

1-23058

1-23113

1-23168

1-23223

50

•23278

•23334

1-23389

1-23444

1-23499

1-23555

1-23610

1-23666

1-23721

1-23777

51

1-23832

•23888

1-23943

1-23999

1-24055

1-24111

1-24166

1-24222

1-24278

1-24334

52

1-24390

•24446

1-24502

1-24558

1-24614

1-24670

1-24726

1-24782

1-24839

1-24895

53

1-24951

•25008

1-25064

1-25120

1-25177

1-25233

1-25290

1-25347

1-25403

1-25460

54

1-25517

•25573

1-25630

1-25687

1-25744

1-25801

1-25857

1-25914

1-25971

1-26028

55

1-26086

•26143

1-26200

1-26257

1-26314

1-26372

1-26429

1-26486

1-26544

1-26601

66

1-26658

•26716

1-26773

1-26831

1-26889

1-26946

1-27004

1-27062

1-27120

1-27177

57

1-27235

•27293

1-27351

1-27409

1-27467

1-27525

1-27583

1-27641

1-27669

1-27758

58

1-27816

1-27874

1-27932

1-27991

1-28049

1-28107

1-28166

•28224

1-28283

1-28342

59

1-28400

1-28459

1-28518

1-28576

1-28635

1-28694

1-28753

•28812

1-28871

1-28930

60

1-28989

1-29048

1-29107

1-29166

1-29225

1-29284

1-29343

•29403

1-29462

1-29521

61

1-29581

1-29640

1-29700

1-29759

1-29819

1-29878

1-29938

•29998

1-30057

1-30117

62

1-30177

1-30237

1-30297

1-30356

1-30416

1-30476

1-30536

•30596

1-30657

1-30717

63

1-30777

1-30837

1-30897

1-30958

1-31018

1-31078

1-31139

•31199

1-31260

1-31320

64

1-31381

1-31442

1-31502

1-31663

1-31624

1-31684

1 31745

•31806

1-31867

1-31928

65

1-31989

1-32050

1-32111

1-32172

1-32233

1-32294

1-32355

1-32417

1-32478

1-32539

66

1-32601

1-32662

1-32724

1-32785

1-32847

1-32908

1-32970

1-33031

1-33093

1-33155

67

1-33217

1-33278

1-33340

1-33402

1-33464

1-33526

1-33588

1-33650

1-33712

1-33774

68

1-33836

1-33899

1-33961

1-34023

1-34085

1-34148

1-34210

1-34273

1-34335

1-34398

69

1-34460

1-34523

1-34585

1-34648

1-34711

1-34774

1-34836

1-34899

1-34962

1-35025

70

1-35088

1-35151

1-35214

1-35277

1-35340

1-35403

1-35466

1-35530

1-35593

1-35656

71

1-35720

1-35783

1-35847

1-35910

1-35974

1-36037

1-36101

1-36164

1-36228

1-36292

72

1-36355

1-36419

1-36483

1-36547

1-36611

1-36675

1-37739

1-36803

1-36867

1-36931

73

1-36995

1-37059

1-37124

1-37188

1-37252

1-37317

1-37381

1-37446

1-37510

1-37575

74

1-37639

1-37704

1-37768

1-37833

1-37898

1-37962

1-38027

1-38092

1-38157

1-38222

75

1-38287

1-38352

1-38417

1-38482

1-38547

1-38612

1-38677

1-38743

1-38808

1-38873

76

1-38239

1-30004

1-39070

1-39135

1-39201

1-39266

1-39332

1-39397

1-39463

1-39529

77

1-39595

1-39660

1-39726

1-39792

1-39858

1-39924

1-39990

1-40056

1-40122

1-40188

78

1-40254

1-40321

1-40387

1-40453

1-40520

1-40586

1-40652

1-40719

1-40785

1-40852

79

1-40918

1-40985

1-41052

1-41118

1-41185

1-41252

1-41318

1-41385

1-41452

1-41519

80

1-41580

1-41653

1-41720

1-41787

1-41854

1.41921

1-41989

1-42056

1-42123

1-42190

81

1-42258

1-42325

1-42393

1-42460

1-42528

1-42595

1-42663

1-42731

1-42798

1-42866

556

APPENDIX.

CORRESPONDENCE BETWEEN BRIX AND SPECIFIC GRAVITY. 1 7 .5 QQ' ~ Continued .

£d
o p5

•0

•1

•2

•3

•4

•5

•6

•7

•8

•9

82

1-42934

1-43002

•43070

1-43137

1-43205

1-43273

1 43341

1-43409

1-43478

1-43546

83

1-43614

1-43682

•43750

1-43819

1-43887

1-43955

1-44024

1-44092

1-44161

1-44229

84

1-44298

1-44367

•44435

1-44504

•44573

•44641

1-44710

1-44779

1-44841

1-44917

85

1-44986

1-45055

•45124

1-45193

•45262

•45331

1-45401

1-45470

1-45539

1-45609

86

1-45678

1-45748

•45817

1-45887

•45956

•46026

1-46095

1-46165

1-46235

1-46304

87

1-46374

1-46444

1-46514

1-46584

•46654

•46724

1-46794

1-46864

1-46934

1-47004

88

1-47074

1-47145

1-47215

1-47285

•47356

•47426

1-47496

1-47567

1-47637

1-57708

89

1-47778

1-47849

1-47920

1-47991

1-48061

•48132

1-48203

1-48274

1-48345

1-48416

90

1-48486

1-48558

1-48629

1-48700

1-48771

•48842

1-48813

1-48985

1-49056

1-49127

91

1-49199

1-49270

1-49342

1-49413

•49485

•49556

1-49628

1-49700

1-49771

1-49843

92

1-49915

1-49987

1-50058

1-50130

•50202

•50274

1-50346

1-50419

1-50491

1-50563

93

1-50635

1-50707

1-50779

1-50852

•50924

•50996

1-51069

1-51141

1-51214

1-51286

94

1-51359

1-51431

1-51504

1-51577

•51640

•51722

1-51795

1-51868

1-51941

1-52014

95

1-52087

1-62159

1-52232

1-52304

52376

•52449

1-52521

1-52593

1-52665

1-52738

96

1-52810

1-52884

1-52958

1-53032

1-53106

•53180

1 53254

1-53328

1-53402

1-53476

97

1-53550

1-53624

1-53698

1-53772

1-53846

•53920

1-53994

1-54068

1-54142

1-54216

98

1-54290

1-54365

1-54440

1-54515

1-54590

1-54665

1-54740

1-54815

1-54890

1-54965

99

1-55040

1-55115

1-55189

1-55264

1-55338

1-55413

1-55487

1-55562

1-55636

1-55711

100

1-55785

557

CANE SUGAR.

CORRESPONDENCE BETWEEN BRIX AND SPECIFIC GRATITY.

20°C.

©

R

•0

•1

•2

•3

•4

•5

•6

•7

•8

•9

0

•99823

•99862

•99901

•99940

•99979

1-00017

1-00056

1-00095

1-00134

1-00173

fir:

1-00212.

1-00251

1-00290

1-00329

1-00367

1-00406

1-00445

1 00484

1-00523

1-00562

,2

1-00601

1-00640

1-00680

1-00719

1-00758

1-00797

1-00836

1-00875

1-00915

1-00954

3

1 00993

1-01033

1.01072

1-01111

1-01151

1-01190

1-01230

1-01269

1-01309

1-01348

4

1-01388

1-01428

1-01467

1-01607

1-01547

1-01586

1-01626

1-01666

1-01706

1-01746

5

1-01785

1-01825

1-01865

1-01905

1-01945

1-01985

1-02025

1-02065

1-02105

1-02145

ai~>

1-02185

1-02226

1-02266

1-02306

1-02346

1-02387

1-02427

1-02467

1-02508

1-09548

7

1-02588

1-02629

1-02669

1-02710

1-02750

1-02791

1-02832

1-02872

1-02913

1-02953

•8

1-02994

1-03035

1-03076

1'03116

1*03157

1-03198

1-03239

1-03280

1-03321

1-03362

9

1 03403

1-03444

1-03485

1 '03526

1-03567

1-03608

1-03649

1-03691

1-03732

1-03773

10

1-03814

1-03856

1-03897

1-03938

1-03980

1-04021

1-04063

1-04104

1-04146

1-04187

11

1-04229

1-04270

1-04312

1-04354

1-04395

1-04437

1-04479

1-04521

1-04562

1-04604

12

1-04646

1-04688

1-04730

1-04772

1-04814

1-04856

1-04898

1-04940

1-04982

1-05024

13

1-05066

1-05109

1-05151

1-05193

1-05236

1-05278

1-05320

1-05363

1-05405

1-05447

14

1-05490

1-05532

1-05575

1-05618

1-05660

1-05703

1-05745

1-05788

1-05831

1-05874

15

1-05916

1-05959

1-06002

1-06045

1-06088

1-06121

1-06174

1-06217

1-06260

1-06303

16

1-06346

1-06389

1-06432

1-06476

1-06519

1-06562

1-06605

1-06649

1-06692

1-06735

17

1-05779

1-06822

1-06866

1-06909

1-06953

1-06996

1-07040

1-07084

1-07127

1-07171

18

1-07215

1-07256

1-07302

1-07346

1-07390

1-07434

1-07478

1-07522

1-07566

1-07610

19

1-07654

1-07698

1-07742

1-07786

1-07830

1-07874

1-07919

1-07963

1-08007

1-08052

20

1-08096

1-08140

1-08185

1-08229

1-08274

1-08318

1-08363

1-08407

1-08452

1-OS497

21

1-08541

1-08586

1-08631

1-08676

1-08720

1-08765

1-08810

1-08855

1-08900

1-08945

22

1-08990

1-09035

1-09080

1-09125

1-OS170

1-C9215

1-09261

1-09306

1-09351

1-09397

23

1-09442

1-09487

1-09533

1-09578

1-09624

1-09669

1-09716

1-09760

1-09806

1-09851

24

1-09897

1-09943

1-09989

1-10034

1-10080

1-10126

1-10172

1-10218

1-10264

1-10310

25

1-10356

1-10402

1-10448

1-10494

1-10540

1-10586

1-10632

1-10679

1-10725

1-10771

26

1-10817

1-10884

1-10910

1-10957

1-11003

1-11050

1-11096

1-11143

1-11189

1-11236

27

1-11283

1-11329

1-11386

1-11423

1-11470

1-11517

1-11563

1-11610

1-11657

1-11714

28

1-11751

1-11798

1-11845

1-11892

1-11939

1-11987

1-12034

1-12081

1-12128

1-12176

29

1-12223

1-12270

1-12318

1-12365

1-12413

1-12460

1-12508

1 12555

1-12603

1-12651

30

1-12698

1-12746

1-12794

1-12842

1-12890

1-12937

1-12985

1-13033

1-13081

1-13129

31

1-13177

1-13225

1-13273

1-13322

1-13370

1-13418

1-13466

1-13515

1-13563

1-13611

32

1-13660

1-13708

1-13756

1-13805

1-13853

1-13902

1-13951

1-13999

1-14048

1-14097

33

1-14145

1-14194

1-14243

1-14292

1-14340

1-14389

1-14438

1-14487

1-14536

1-14585

34

1-14634

1-14684

1-14733

1-14782

1-14831

1-14880

1-14930

1-14979

1-15029

1-15078

35

1-15127

1-15177

1-15226

1-15276

1-15326

1-15375

1-15425

1-05475

1-15524

1-15574

36

1-15624

1-15674

1-15724

1-15773

1-15823

1-15873

1-15923

1-15973

1-16023

1-16073

558

APPENDIX.

CORRESPONDENCE BETWEEN BRIX AND SPECIFIC GRAVITY. —57=^— Continued.

l&
I«

•0

•1

•2

•3

•4

•5

•6

•7

•8

•9

37

1-16124

1-16174

1-16224

1-16274

1-15324

1-16375

1-16425

1-16476

1-16526

1-16576

38

1-16627

1-16677

1-16728

1-16779

1-16829

1-16880

1-16931

1-16981

1-17032

1-17083

39

1-17134

1-17185

1-17236

1-17287

1-17338

1-17389

1-17440

1-17491

1-17542

1-17593

40

•17^45

1-17696

1-17747

1-17799

1-17850

1-17901

1-17953

1-18004

1-18560

1-18108

41

•18159

1-18211

1-18262

1-18314

1-18366

1-18418

1-18470

1-18521

1-18573

1-18625

42

•18677

1-18729

1-18781

1-18833.

1-18886

1-18938

1-18990

1-19042

1-19095

1-19147

43

•19199

1-19252

1-19304

1-19356

1-19409

1-19462

1-19514

1-19567

1-19619

1-19672

44

•19725

1-19777

1-19830

1-19883

1-19936

1-19989

1-20042

1-20095

1-20148

1-20201

45

•20254

1-20307

1-20360

1-20414

1-20467

1-20520

1-20573

1-20627

1-20680

1-20733

46

•20787

1-20840

1-20894

1-20945

1-21001

1-21055

1-21109

1-21162

1-21216

1-21270

47

•21324

1-21378

1-21432

1-21486

1-21539

1-21594

1-21648

1-21702

1-21756

1-21810

48

•21864

1-21918

1-21973

1-22027

1-22081

1-22136

1-22190

1-22245

1-22299

1-22354

49

1-22409

1-22463

1-22518

1-22573

1-22627

1-22682

1-22737

1-22792

1«22847

1-22902

50

1-22957

1-23012

1-23067

1-23122

1-23177

1-23232

1-23287

1-23343

1-23398

1-23453

51

1-23508

1-23564

1-23619

1-23675

1-23730

1-23786

1-23841

1-23897

1-23953

1-24008

52

1-24064

1-24120

1-24176

1-24231

1-24287

1-24343

1-24399

1-24452

1-24511

1-24567

53

1-24623

1-24679

1-24736

1-24792

1-24848

1-24905

1-24961

1-25017

1-25074

1-25130

54

1-25187

1-25243

1-25300

1-25356

1-25413

1-25470

1-25526

1-25583

1-25640

1-25897

55

1-25753

1-25810

1-25867

1-25924

1-25981

1-26038

1-26095

1-26153

1-26210

1-26267

56

1-26324

1-26382

1-26439

1-26496

1-26554

1-26611

1-26669

1-26726

1-26784

1-26841

57

1-26899

•26956

1-27014

1-27072

1-27130

1-27188

1-27245

1-27303

1-27361

1-27419

58

1-27477

1-27535

1-27594

1-27652

1-27710

1-27768

1-27826

1-27884

1-27943

1-28001

59

1-28059

•28118

1-28176

1-28235

1-28293

1-28352

1-28411

1-28469

1-28528

1-28587

60

1-28646

•28704

1-28763

1-28822

1-28881

1-28940

1-28999

1-29058

1-29117

1-29176

61

1-29235

•29295

1-29354

1-29413

1-29472

1-29532

1-29591

1-29651

1-29710

1-29770

62

1-29829

•29889

1-29948

1-30008

1-30068

1-30127

1-30187

1-30247

1-30307

1-30367

63

1-30427,

1-30487

1-30547

1-30607

1-30667

1-30727

1-30787

1-30847

1-30908

1-30968

64

1-31028

1-31088

1-31149

1-31209

1-31270

1-31330

1-31391

1-31451

1-31512

1-31573

65

1-31633

1-31694

1-31755

1-31816

1-31897

1-31937

1-31998

1-32059

1-32120

1-32184

66

1-32242

1-32304

1-32365

1-32426

1-32487

1-32548

1-32610

1-32671

1-32732

1-32795

67

1-32855

1-32917

1-32978

1-33040

1-33102

1-33163

1-33225

1-33287

1-33348

1-33410

68

1-33472:

1-33534

1-33596

1-33658

1-33720

1-33782

1-33844

1-33906

1-33968

1-34031

69

1-34093

1-34155

1-34217

1-34280

1-34342

1-34405

1-34467

1-34530

1-34592

1-34655

70

1-34717

1-34780

1-34843

1-34905

1-34968

1-35031

1-35094

1-35157

1-35220

1-35283

71

1-35346

1-35409

1-35472

1-35535

1-35598

1-35P61

1-35724

1-35788

1-35851

1-35914

72

1-35978

1-36041

1-36105

1-36168

1-36232

1-36295

1-36359

1-36423

1-36486

1-36550

73

1-36614

1-36678

1-36741

1-36805

1-36869

1-36933

1-36997

1-37061

1-37124

1-37189

74

1-37254

1-37318

1-37382

1-37446

1-37510

1-37575

1-37639

1-37704

1-37768

1-37833

75

1-37897

1-37962

1-38026

1-38091

1-38155

1-38220

1-38285

1-38350

1-38415

1-38480

76

1-38545

1-38610

1-38674

1-38740

1-38804

1-38870

1-38935

1-39000

1-39065

1-39130

77

1-39196

1-39261

1-39326

1-39392

1-39457

1-39523

1-39588

1-39654

1-39719

1-39785

78

1-39850

1-39916

1-39982

1-40048

1-40113

1-40179

1-40245

1-40311

1-40377

1-40443

559

CANE SUGAK.

CORRESPONDENCE BETWEEN BRIX AND SPECIFIC GRAVITY.

20°C.
4°C.

— Continued.

f!

•0

•1

•2

•3

•4

•5

•6

•7

•8

•9

79

•40509

1-40575

1-40641

1-40707

1-40773

1-40840

1-40906

1-40972

1-41039

1-41105

80

•41175

1-41238

1-41304

1-41371

•41437

1-41544

1-41571

1-41637

1-41704

1-41771

81

•41837

1-41904

1-41971

1-42038

•42105

1-42172

1-42239

1-42309

1-42373

1-42440

82

•42507

1-42574

1-42642

1-42709

1-42776

1-42843

1-42911

1-42978

1-43046

1-43113

83

•43181

1-43248

1-43316

1-43383

•43451

1-43519

1-43587

1-43654

1-43722

1-43790

84

•43858

1-43926

1-43994

1-44062

•44130

1-44198

1-44266

1-44334

1-44402

1-44470

85

•44539

1-44607

1-44675

1-44744

•44812

1-44881

1-44939

1-45017

1-45086

1-45154

86

•45223

1-45292

1-45360

1-45429

•45499

1-45566

1-45636

1-45704

1-45773

1-45842

87

•45911

1-45980

1-46049

1-46119

•46189

1-46257

1-46326

1-46395

1-46464

1-46534

88

•46603

1-46673

1-46742

1-46811

•46881

1-46950

1-47020

1-47090

1-47159

1-47229

89

•47299

1-47368

1-47438

1-47508

1-47578

1-47648

1-47718

1-47788

1 47357

1-47927

90

•47998

1-48068

1-48138

1-48208

1-48278

1-48348

1-48419

1-48489

1-48559

1-48630

91

•48700

1-48771

1-48841

1-48912

1-48982

1-49053

1-49123

1-49194

1-49265

1-49335

92

•49406

1-49477

1-49548

1-49619

1-49690

1-49761

1-49832

1-49903

1-49974

1-50045

93

•50116

1-50187

1 50258

1-50329

1-50401

1-50472

1-50543

1-50615

1-50686

1-50757

94

1-50829

1-50900

1-50972

1-51043

1-51115

1-51187

1-51258

1-51330

1-51402

1-51474

95

1-51545

1-51617

1-51689

1-51761

1-51833

1-51905

1-51987

1-52049

1-52121

1-52193

96

1-52266

1-52338

1-52410

1-42482

1-52555

1-52627

1-52699

1-52772

1-52844

1-52917

97

1-52989

1-53062

1-53134

1-53207

1-53279

1-53352

1-53425

1-53498

1-53570

1-53643

98

1-53716

1-53789

1-53862

1-53935

1-54008

1-54081

1-54154

1-54227

1-54300

1-54373

99

1-54446

1-54519

1-54593

1-54666

1-54729

1-54813

1-54886

1-54959

1-55033

1-55106

100

1-55180

560

APPENDIX.

TEMPERATURE CORRECTIONS FOR BRIX HYDROMETER
GRADUATED AT 17'5°C.

DEGREES BRIX.

0

5

10

15

20

25

30

35

40

50

60

70

75

Tempera
ture.

SUBTRACT FROM THE OBSERVED HEADING

15

0-09

0-11

0-12

0-14

0-14

0-15

0-16

0-17

0-16

0-17

0-19

0-21

0-25

16

0-06

0-07

0-08

0-09

0-10

0-10

0-11

0-12

0-12

0-12

0-14

0-16

0-18

17

0-02

0-02

0-03

0-03

0-03

0-04

0-04

0-04

0-04

0-04

0-05

0-05

0-06

Tempera
ture.

ADD TO THE OBSERVED READING

18

0-02

0-03

0-03

0-03

0-03

0-03

0-03

0-03

0-03

0-03

0-03

0-03

0-02

19

0-06

0-08

0-08

0-09

0-09

o-io

0-10

0-10

0-10

0-10

0-10

0-08

0-06

20

0-11

0-14

0-15

0-17

0 17

0-18

0-18

0-18

0-19

0-19

0-18

0-15

0-11

21

0-16

0-20

0-22

0-24

0-24

0-25

0-25

0-25

0-26

0-26

0-25

0-22

0-18

22

0-21

0-26

0-29

0-31

0-31

0-32

0-32

0-32

0-33

0-34

0-32

0-29

0-25

23

0-27

0-32

0-35

0-37

038

0-39

0-39

0 39

0-40

0-42

0-39

0-36

0-33

24

0-32

0-38

0-41

0-43

0-44

0-46

0-46

0-47

0-47

0-50

0-46

0-43

0-40

25

0-37

0-44

0-47

0-49

0-51

0-53

0-54

0-55

0-55

0-58

0-54

0-51

0-48

26

0-43

0-50

0-54

0-56

0-58

0-60

0-61

0-62

0-62

0-66

0-62

0-58

0-55

27

0-49

0-57

0-61

0-63

0-65

0-68

0-68

0-69

0-70

0-74

0-70

0-65

0-62

26

0-56

0-64

0-68

0-70

0-72

0-76

0-76

0-78

0-78

0-82

0-78

0-72

0-70

29

0-63

0-71

0-75

0-78

0-79

0-84

0-84

0-86

0-86

0-90

0-86

0-80

0-78

30

0-70

0-78

0-82

0-87

0 87

0-92

0-92

0-94

0-94

0-98

0-94

0-88

0-86

35

1-10

1-17

1-22

1-24

1-30

1-32

1-33

1-35

1-36

1-39

1-34

1-27

1-25

40

1-50

1-61

1-67

1-71

1-73

1-79

1-79

1-80

1-82

1-83

1-78

1-69

1-65

50

2-65

2-71

2-74

2-78

2-80

2-80

2-80

2-80

2-79

2-70

2-56

2-51

60

3-87

3-88

3-88

3-88

3-88

3-88

3-88

3-90

3-82

3-70

3-43

3-41

70

5-17

5-18

5-20

5-14

5-13

5-10

5-08

5*06

4-90

4-72

4-47

4-35

80

6-62

6-59

6-54

6-46

6-38

6-30

6-26

6-06

5-82

6-50

5-33

90

8-26

8-16

8-06

7-97

7-83

7-71

7-58

7-30

6-96

6-58

6-37

100

10-01

9-87

9-72

9-56

9-39

9-21

9-03

8-64

8-22

7-76

7-42

561

36

CANE SUGAR.

TEMPERATURE CORRECTIONS FOR BRIX HYDROMETER
GRADUATED AT 27-5° C.

DEGREES BRIX.

0

5

10

15

20

25

30

35

40

50

Tempera-
ture.

SUBTRACT FROM THE OBSERVED READING

15

0-61

0-71

0-75

0-80

0-82

0-87

0-88

0-91

0-91

0-95

16

0-58

0-67

0-71

0-75

0-78

0-82

0-83

0-86

0-87

0-90

17

0-54

0-62

0-66

0-69

0-71

0-76

0-76

0-78

0-79

0-82

18

0-50

0-57

0-60

0-63

0-65

0-69

0-69

0-70

0-71

0-75

19

0-46

0-52

0-55

0-57

0-59

0-62

0-62

0-63

0-64

0-68

20

0-41

0-46

0-48

0-49

0-51

0-54

0-54

0-55

0-56

0-59

21

0-36

0-40

0-41

0-42

0-44

0-47

0-47

0-48

0-48

0-52

22

0-31

0-34

0-34

0-35

0-37

0-40

0-40

0-41

0-41

0-44

23

0-25

0-28

0-28

0-29

0-30

0-33

0-33

0-34

0-34

0-36

24

0-20

0-22

0-22

0-23

0-23

0-26

0-26

0-26

0-26

0-28

25

0-15

0-16

0-16

0-17

0-17

0-19

0-16

0-19

0-19

0-20

26

0-09

0-10

0-10

o-io

0-10

0-12

0-12

0-12

0-12

0-21

27

0-03

0-03

0-03

0-03

0-03

0-04

0-04

0-04

0-04

0-04

Tempera-
ture.

ADD TO THE OBSERVED READING

28

0-04

0-04

0-04

0-04

0-04

0-04

0-04

0-04

0-04

0-04

29

0-11

0-11

0-11

0-11

0-11

0-12

0-12

0-12

0-12

0-12

30

0-18

0-19

0-19

0-19

0-19

0-20

0-20

0-20

0-20

0-20

31

0-26

0-27

0-27

0-28

0-28

0-28

0-28

0-28

0-28

0-28

32

0-34

0-35

0-35

0-35

0-35

0-36

0-36

0-?6

0-36

0-36

33

0-42

0-42

0-42

0-42

0-43

0-44

0-44

0-44

0-44

0-44

34

0-50

0-50

0-50

0-50

0-51

0-52

0-52

0-52

0-52

0-52

35

0-58

0-58

0-59

0-59

0-60

0-60

0-61

0-61

0-61

0-61

562

APPENDIX.

TABLE OP DBY SUBSTANCE FROM KEFRACTIYE INDEX AT 28° C,

(H. C. Prinsen Geerligs.)

Index.

Per Cent
Dry Sub-
stance.

Index.

Per Cent.
Dry Sub-
stance.

Index.

Per Cent.
Dry Sub-
stance.

Index.

Per Cent.
Dry Sub-
stance.

Index.

Per Cent,
Dry Sub-
stance.

1'3335

1-00

1-3405

570

1-3475

10-40

1-3545

14-95

1-3615

19-25

36

1-05

06

5'80

76

10-45

46

15 00

16

1930

37

1-10

07

5-85

77

10-50

47

15-05

17

19-40

38

1-20

08

5-90

78

10-60

48

15'10

18

19-45

39

130

09

6-00

79

10-65

49

15-20

19

19-50

1-3340

1-35

1-3410

6-05

1'3480

10'70

1-3550

15-25

1-3620

19-60

41

1-40

11

6-10

81

10-80

51

15-30

21

19-65

42

1-50

12

6-20

82

10-85

52

15-40

22

19-70

43

1-60

13

6-25

83

10-90

53

15-45

23

19-75

44

1-65

14

6-30

84

11-00

54

15-50

24

19-80

45

1'70

15

6-40

85

11-05

55

15-60

25

19-85

46

1-80

16

6-45

86

1110

56

1565

26

19-90

47

1*86

17

6-50

87

11-20

57

15-70

27

2000

48

T90

18

6'60

88

1125

58

15-75

28

20-05

49

2-00

19

6-65

89

11-30

59

15-80

29

20-10

1.3350

2'05

1-3420

6-70

1-3490

11 40

1-3560

15'85

1-3630

20-15

51

2-10

21

6-80

91

11-45

61

1590

31

20-20

52

2-20

22

6-85

92

11 '50

62

16-00

32

20-30

53

225

23

6-90

93

11-60

63

16-05

33

20-35

54

2-30

24

7'00

94

11-65

64

16-10

34

20-40

55

2-40

25

7'05

95

11-70

65

16-20

35

2045

56

2-45

26

7-10

96

11-75

66

16-25

36

20-50

57

2'50

27

7-20

97

11-80

67

1630

37

20-60

58

2-60

28

7-25

98

11-85

68

16-40

38

20-65

59

2-65

29

7-30

99

11-90

69

1645

39

2070

1.3360

2'70

1-3430

7-40

1-3500

12-00

1-3570

16-50

1-3640

20-80

61

2-80

31

7-45

01

12-05

71

16-60

41

20-85

62

2-85

32

750

02

12-10

72

16-65

42

2090

63

2' 90

33

7-60

03

12-20

73

16-70

43

20-95-

64

3'00

34

7-65

04

12'25

74

16-75

44

21-00

65

3'05

35

7-70

05

12-30

75

16-80

45

21-05-

66

3-10

36

7-80

06

1240

76

16-85

46

21-10

67

3-20

37

7-85

07

12-45

77

16-90

47

21-15

68

3'25

38

7-90

08

12-50

78

17-00

48

21-20

69

3-30

39

8-00

09

12-60

79

1705

49

21-30

1-3370

3-40

1-3440

8-05

1-3510

12-65

1-3580

17-10

1-3650

21-35

71

3-45

41

8-10

11

12-70

81

1720

51

21-40

72

3'50

42

8-20

12

12-75

82

17-25

52

21-45

73

3-60

43

8-25

13

12-80

83

17-30

53

21-50

74

3-65

44

830

14

12-85

84

17-40

54

21-60

75

3'70

45

8-40

15

12-90

85

17-45

55

21-65

76

3'80

46

8-45

16

13-00

86

17-50

56

21-70

77

3'85

47

8-50

17

13-10

87

1760

57

2180

78

3'90

48

8-60

18

13-20

88

17-65

58

21-85

79

400

49

8-65

19

13-25

89

17*70

59

-21-90

1'3380

4-05

1-3450

8-70

1-3520

13-30

1-3590

17-75

1-3660

21-95

81

4'10

51

8-80

21

13-40

91

17-80

61

22-00

82

420

52

8-85

22

13-45

92

17-85

62

22-05

83

4-25

53

8-90

23

13-50

93

17-90

63

22-10

84

4-30

54

9-00

24

13-60

94

18-00

64

22-15

85

4-40

55

9-05

25

13-65

95

18-05

65

22-20

86

4'45

56

9-10

26

13-70

96

18-10

66

22-30

87

450

57

9-20

27

13-80

97

1815

67

22-35

88

4-60

58

9-25

28

13-85

98

18-20

68

22-40

89

4-65

59

9'30

29

1390

99

1830

69

2245

1'3390

4-70

1-3460

9-40

1-3530

14-00

13600

18-35

1-3670

22-50

91

4'80

61

9-45

31

14-05

01

1840

71

22-60

92

4'85

62

9-50

32

14 10

02

18-45

72

22-65

93

4-90

63

9-60

33

14-20

03

18-50

73

22-70

94

5-00

64

965

34

14-25

04

18'60

74

22-80

95

5-05

65

9-70

35

14-30

05

18-65

75

22-85

96

5-10

66

9-80

36

1440

06

1870

76

22-90

97

5-20

67

9-85

37

14-45

07

18-80

77

2295

98

5-25

68

9-90

38

14-50

08

18-85

78

2300

99

5-30

69

10-00

39

14-60

09

18-90

79

23-05

1-3400

5-40

1-3470

10-05

1-3540

14-65

1-3610

18-95

1-3680

2310

01

5-45

71

10-10

41

1470

11

19-00

81

23-15

02

550

72

10'20

42

14-80

12

19-05

82

23-20

03

5-60

73

10-25

43

14-85

13

19-10

83

23-30

04

5-65

74

10-30

44

14-90

14

19-20

84

23-35

563

CANE SUGAR.
TABLE OF DRY SUBSTANCE FROM EEFRACTIVE INDEX AT 28° 0. — Continued.

Index.

Per Cent
Dry Sub-
Stance.

Index.

Per Cent
Dry Sub-
stance.

Index.

Per Cent
Dry Sub-
stance.

Index.

Per Cent
Dry Sub-
stance.

Index.

Percent.
Dry Sub-
stance.

1-3685

23-40

1-3765

28-05

1-3845

32-50

1-3925

36-85

1-4005

41-10

86

23-45

66

28-10

46

32-55

26

36-90

06

41-15

87

23-50

67

28-15

47

32-60

27

36-95

07

41-20

88

23-60

68

2820

48

32-65

28

37-00

08

41-25

89

23-65

69

2830

49

32-70

29

37-05

09

41-30

1-3690

2370

1-3770

28-35

1-3850

32-80

1-3930

37-10

1-4010

41-35

91

23-80

71

2840

51

3285

31

37-15

11

41-40

92

23-85

72

28-45

52

3290

32

37-20

12

41-45

93

23-90

73

28-50

53

32-95

33

37-25

13

41-50

94

23-95

74

28-60

54

33-00

34

37-30

14

41-55

95

24-00

75

28-65

55

33-05

35

37-35

15

41-60

96

24-05

76

28-70

56

33-10

36

37-40

16

41-65

97

24-10

77

28-75

57

33-15

37

3745

17

41 70

98

24-15

78

28-80

58

33-20

38

37-50

18

41-75

99

24-20

79

28-85

59

3330

39

3760

19

41-80

1-3700

2430

1-3780

28-90

1-3860

33-35

1-3940

37-65

1-4020

41-85

01

24-35

81

28-95

61

33-40

41

37 70

21

4190

02

24-40

82

29-00

62

33-45

42

3775

22

41-95

03

24-45

83

29-05

63

33-50

43

37-80

23

42-00

04

2450

84

29-10

64

3355

44

3785

24

42-05

05

24-60

85

29-15

65

33-60

45

37-90

25

42-10

06

24-65

86

29-20

66

33-65

46

37-95

26

4215

07

24-70

87

29-30

67

3370

47

38 00

27

42-20

08

24-80

88

29-35

68

3380

48

38-05

28

42-25

09

24-85

89

2940

69

3385

49

38 10

29

4230

1-3710

24-90

1*3790

29-45

1-3870

33-90

1-3950

38-15

1-4030

42-35

11

24-95

91

29-50

71

3395

51

38-20

31

42-40

12

25-00

92

29-60

72

34-00

52

38-25

32

42-45

13

25-05

93

29-65

73

34-05

53

38-30

33

42-50

14

25-10

94

29-70

74

34*10

54

38-35

34

42-55

15

25-15

95

2975

75

3415

55

38-40

35

42-60

16

25-20

96

29-80

76

3420

56

38-45

36

42-65

17

25-30

97

29-85

77

34-30

57

38-50

37

42-70

18

25-35

98

29-90

78

34-35

58

38-60

38

42'75

29

25-40

99

2995

79

3440

59

38-65

39

4280

'3720

2545

1-3800

30-00

1-3880

34-45

1-3960

38-70

1-4040

42-85

21

25-50

01

30-05

81

34-50

61

38-75

41

42-90

22

25-60

02

30-10

82

34-55

62

38-80

42

42-95

23

25-65

03

30-15

83

34-60

63

38-85

43

43-00

24

25-70

04

30-20

84

3465

64

38-90

44

43-05

25

25-80

05

30-30

85

34-70

65

38-95

45

43-10

26

25-85

06

30-35

86

34-80

66

39-00

46

43-15

27

25-90

07

30-40

87

34-85

67

39-05

47

43-20

28

25-95

08

30-45

88

34-90

68

39-10

48

43-25

39

2600

09

3050

89

3495

69

39-15

49

43-30

1-3730

26-05

1-3810

30-55

1-3890

35-00

1-3970

39-20

1-4050

43-35

31

26-10

11

30-60

91

35-05

71

39-30

51

43'40

32

2615

12

30-65

92

3510

72

39-35

52

43-45

33

26-20

13

30 '70

93

35-15

73

39-40

53

4350

34

26-30

14

30-80

94

35-20

74

39-45

54

43-55

35

2635

15

30-85

95

35-25

75

3950

55

43-60

36

26-40

16

30-90

96

35-30

76

3955

56

4365

37

26-45

17

30-95

97

3535

77

39-60

57

43-70

38

26-50

18

31-00

98

35-40

78

39-65

58

43-75

39

26-60

19

31-05

99

3545

79

39-70

59

43-80

1-3740

2665

1-3820

31-10

1-3900

35-50

1-3980

39-80

1-4060

43-85

41

26-70

21

31-15

01

35-60

81

39-85

61

43-90

42

26-80

22

31-20

02

3565

82

3990

62

43-95

43

26'85

23

31-30

03

35-70

83

39-95

63

44-00

44

26-90

24

31-35

04

35-75

84

40-00

64

44-05

45

26-95

25

31-40

05

35-80

85

4005

65

44-10

46

27-00

26

31-45

06

35-85

86

40-10

66

44-15

47

27-05

27

31-50

07

35-90

87

40-15

67

44-20

48

27-10

28

31-55

08

35-95

88

40-20

68

44-25

49

27-15

29

31-60

09

36-00

89

40-25

69

44-30

1-3750

2720

1-3830

31-65

1-3910

36-05

1-3990

40-30

1-4070

44-35

51

27-30

31

31-70

11

36-10

91

40-35

71

44-40

52

27-35

32

31-80

12

36-15

92

40-40

72

44-45

53

27-40

33

31-85

13

36-20

93

40-45

73

44-50

54

27-45

34

31-90

14

36-25

94

4050

74

44-55

55

2750

35

31-95

15

36-30

95

40-60

75

44-60

56

27-60

36

32-00

16

36-35

96

40 65

76

44-65

57

27-65

37

32-05

17

36-40

97

40-70

77

44-70

58

27-70

38

32-10

18

36-45

98

40-75

78

44-75

59

27-75

39

32-15

19

36-50

99

40-80

79

44-80

1-3760

27-80

1-3840

32-20

1-3920

36-60

1-4000

4085

1-4080

44-85

61

27-85

41

32-30

21

36-65

01

40-90

81

44-90

62

27-90

42

32-35

22

36-70

02

40-95

82

44-95

63

2795

43

32-40

23

36-75

03

41-00

83

45-00

64

28-00

44

32-45

24

36-80

04

41-05

84

45-05

564

APPENDIX.
TABLE OF DRY SUBSTANCE FROM EEFRACTIVE INDEX AT 28° 0.— Continued.

Index.

Per Cent
Dry Sub
stance.

Index.

Per Cent
Dry Sub
stance.

Index.

Per Cent
Dry Sub
stance.

Index.

Per Cent
Dry Sub-
stance.

Index.

Per Cent.
Dry Sub-
stance.

1-4085

45-10

1-4165

48-95

1-4245

52-80

1-4325

56-50

1-4405

60-00

86

45-15

66

49-00

46

5285

26

56-53

06

60-05

87

45-20

67

49-05

47

52-90

27

56-55

07

60-10

88

45-25

68

49-10

48

5295

28

56-60

08

60-15

89

45-30

69

49-15

49

53-00

29

5665

09

60-20

1-4090

45-35

1-4170

49-20

1-4250

53-05

1-4330

56-70

1-4410

60-23

91

4540

71

49-25

51

53-10

31

56-75

11

60-25

92

45-45

72

4930

52

53-15

32

5680

12

60-30

93

45-50

73

49-35

53

5320

33

5683

13

60-35

94

4553

74

49-40

54

53-25

34

5685

14

60-40

95

45-55

75

49-45

55

53-30

35

5690

15

60-45

96

4560

76

49-50

56

53-35

36

56-95

16

60-50

97

45-65

77

49-55

57

53-40

37

5700

17

60-53

98

45-70

78

49-60

58

53-45

38

57-05

18

60-55

99

4575

79

49-65

59

5350

39

57-10

19

60-60

1M100

4580

1-4180

49-70

1-4260

5353

1-4340

57-15

1-4420

60-65

01

45-85

81

49-75

61

53-55

41

57-20

21

60-70

02

45-90

82

49-80

62

5360

42

5723

22

60-75

03

45-95

83

49-85

63

53-65

43

57-25

23

60-80

04

46-00

84

49-90

64

53-70

44

57-30

24

60-83

05

46-05

85

49-95

65

53-75

45

57-35

25

60-85

06

46-10

86

50-00

66

53-80

46

57-40

26

60-90

07

46-15

87

50-05

67

53-85

47

57-45

27

60'95

08

46-20

88

50-10

68

53-90

48

57-50

28

61-00

09

46-25

89

50-15

69

53-95

49

57-55

29

61.05

1-4110

46-30

1-4190

50-20

1-4270

54-00

1-4350

57-60

1-4430

61-10

11

4635

91

50-25

71

54-05

51

5765

31

61-15

12

46-40

92

50-30

72

54-10

52

57-70

32

61-20

13

46-45

93

50-35

73

54-15

53

57-73

33

61-23

14

46-50

94

50-40

74

54-20

54

57-75

34

61-25

15

46-55

95

50-45

75

5423

55

57-80

35

61-30

16

46-60

96

50-50

76

54-25

56

57-85

36

61-35

17

46-65

97

50-53

77

54-30

57

57-90

37

61-40

18

46-70

98

50-55

78

54-35

58

57-95

38

61-45

19

46-75

99

50-60

79

54-40

59

5800

39

61-50

1-4120

46-80

1-4200

50-65

1-4280

5445

1-4360

5805

1-4440

61-53

21

46-85

01

50-70

81

54-50

61

5810

41

61-55

22

46-90

02

50-75

82

54-55

62

58-15

42

61-60

23

46-95

03

5080

83

54-60

63

5820

43

61-65

24

47-00

04

5085

84

5465

64

58-23

44

61-70

25

4705

05

5090

85

54-70

65

5825

45

61-75

26

47-10

06

50 95

86

54-73

66

58-30

46

61-80

27

47-15

07

51-00

87

54-75

67

5835

47

61-83

28

4720

08

5105

88

54-80

68

58-40

48

61-85

29

47-25

09

51-10

89

5485

69

5845

49

6190

1-4130

47-30

1-4210

51-15

1-4290

54-90

1-4370

58-50

1-4450

61-95

31

47-35

11

51-20

91

54.-9S

71

58-53

51

62-00

32

47-40

12

51-25

92

5500

72

5855

52

62-05

33

47-45

13

51-30

93

55-05

73

58-60

53

62-10

34

47-50

14

51-35

94

55-10

74

58-65

54

62-15

35

47-53

15

51 40

95

55-15

75

58-70

55

62-20

36

47-55

16

51-45

96

55-20

76

58-75

56

62-23

37

47-60

17

51-50

97

55-23

77

58-80

57

62-25

38

47-65

18

51 53

98

55-25

78

58-83

58

62-30

39

4770

19

51-55

99

55-30

79

58-85

59

6235

14140

47-75

1-4220

5160

1-4300

5535

1-4380

58-90

1-4460

62-40

41

47-80

21

51-65

01

55-40

81

58-95

61

62-45

42

47-85

22

51-70

02

55-45

82

59-00

62

62-50

43

47-90

23

51-75

03

55-50

83

59-05

63

62-53

44

4795

24

5180

04

55-55

84

59-10

64

62-55

45

48-00

25

51-85

05

55-60

85

59-15

65

62-60

46

48-05

26

51-90

06

55-65

86

59-20

66

62-65

47

4810

27

51-95

07

55-70

87

59-23

67

62-70

48

48-15

28

5200

08

55-73

88

59-25

68

62-75

49

48-20

29

52-05

09

55-75

89

5930

69

62-80

1-4150

48-25

1-4230

5210

1-4310

5580

1-4390

59-35

1-4470

62-83

51

48-30

31

5215

11

55-85

91

59-40

71

62-85

52

48-35

32

52-20

12

55-90

92

59-45

72

62-90

53

48-40

33

5225

13

5595

93

5950

73

6295

54

4845

34

5230

14

56-00

94

59-53

74

6300

55

48-50

35

5235

15

5605

95

59-55

75

6305

56

48-53

36

52-40

16

56-10

96

59-60

76

63-10

57

48-55

37

52-45

17

56-15

97

59-65

77

63-15

58

48'60

38

52-50

18

5620

98

5970

78

6320

59

48-65

39

52-53

19

5623

99

59-75

79

6323

1-4160

48-70

1'4240

52-55

1-4320

56-25

1-4400

59-80

1-4480

ej-f

61

48-75

41

52-60

21

5630

01

59-83

81

63-30

62

48-80

42

52-65

22

56-35

02

59-85

82

63-35

63

48-85

43

52-70

23

56-40

03

59-90

83

63-40

64

48-90

44

52-75

24

56-45

04

59-95

84

6345

565

CANE SUGAR.

TABLE or DRY SUBSTANCE FROM REFRACTIVE INDEX AT 28° 0. — Continued.

Index.

Per Cent.
Dry Sub-
stance.

Index.

Per Cent.
Dry Sub-
stance.

Index.

Per Cent.
Dry Sub-
stance.

Index.

Per Cent.
Dry Sub-
stance.

Index.

Per Cent.
Dry Sub-
stance.

1-4485

63'50

1-4565

66-90

1-4645

7025

1-4725

73-55

1-4805

76-75

86

63-53

66

66-95

46

70-30

26

7360

06

76-80

87

63-55

67

67-00

47

7035

27

73-63

07

76-83

88

63-60

68

67-05

48

70-40

28

7365

08

76-85

89

63-65

69

67-10

49

70-43

29

73-70

09

76-90

1-4490

63-70

1-4570

67-15

1-4650

70-45

1-4730

73-75

1-4810

76-95

31

63-75

71

67.20

51

70-50

31

73-80

11

77-00

92

63-80

72

6723

52

7055

32

7383

12

77-03

-93

63-83

73

67-25

53

70-60

33

73-85

13

77-05

94

6385

74

67-30

54

70-63

34

73-90

14

77-10

•95

6390

75

67-35

55

7065

35

73-95

15

7715

96

63-95

76

67-40

56

70-70

36

74-00

16

77-20

91

64-00

77

67-43

57

7075

37

74-03

17

77-23

98

64-05

78

67-45

58

70 '80

38

74-05

18

77-25

99

64-10

79

67-50

59

7083

39

74-10

19

77-30

1-4500

64-15

1-4580

67-55

1-4660

70-85

1-4740

74-15

1-4820

77-35

01

64-20

81

67-60

61

70-90

41

74-20

21

77-40

02

64-23

82

67-63

62

70-95

42

74-23

22

77-43

03

6425

83

67-65

63

7100

43

7425

23

77-45

04

64-30

84

67-70

64

71-05

44

74-30

24

77-50

05

64-35

85

67-75

65

71-10

45

74-35

25

77-55

06

64-40

86

6780

66

71-15

46

74-40

26

77-60

07

64-45

87

67-83

67

71-20

47

74-43

27

77-63

08

64-50

88

67-85

68

71-23

48

74-45

28

77-65

09

64-53

89

67-90

69

71-25

49

74-50

29

77-70

1-1510

64-55

1-4590

67-95

1-4670

71-30

1-4750

74-55

1-4830

77-75

11

6460

91

6800

71

71-35

51

74-60

31

77-80

12

64-65

92

68-05

72

71-40 •

52

74-63

32

77'83

13

64-70

93

68-10

73

71-43

53

74-65

33

7785

14

64-75

94

68-15

74

7145

54

74-70

34

77-90

15

6480

95

6820

75

71-50

55

74-75

35

77-95

16

64-83

96

68-23

76

71-55

56

74-80

36

78-00

17

64-85

97

68-25

77

71-60

57

74-83

37

78-03

18

64-90

98

68-30

78

71-63

58

74-85

38

78-05

19

64-95

99

68-35

79

7165

59

74-90

39

78-10

1-1520

6500

1-4600

68-40

1-4680

71-70

1-4760

74-95

1-4840

78-15

21

65-05

01

6843

81

71-75

61

75-00

41

7820

22

65-10

02

68-45

82

7180

62

75-03

42

78-23

23

65-15

03

68-50

83

7183

63

75-05

43

78-25

24

65-20

04

6855

34

71-85

64

75-10

44

78-30

25

65-23

05

68-60

85

71-90

65

75-15

45

78 '35

26

65-25

06

68-63

86

71-95

66

75-20

46

78-40

27

65-30

07

68-65

87

7200

67

75-23

47

78-43

28

65-35

08

68-70

88

7205

68

75-25

48

78-45

29

65-40

09

68-75

89

7210

69

75-30

49

78-50

1-4530

65-45

1-4610

6880

1-4690

7215

1-4770

75-35

1-4850

78-53

31

65-50

11

68*83

91

72-20

71

75-40

51

78-55

32

65-53

12

68-85

92

72-23

72

75-43

52

7860

33

65-55

13

68-90

93

72-25

73

75-45

53

78-63

34

65-60

14

68-95

94

7230

74

75-50

54

78-65

35

65-65

15

6900

95

72-35

75

7555

55

7870

36

6570

16

69-05

96

72-40

76

75-60

56

78-75

37

6575

17

69-10

97

72-43

77

75-63

57

78-80

38

6580

18

69-15

98

72-45

78

75-65

58

78-83

39

65-83

19

6920

99

72-50

79

75-70

59

78-85

1-4540

65-85

1-4620

6923

1-4700

7255

1-4780

75-75

1-4860

78-90

41

65-90

21

6925

01

7260

81

75-80

61

78-95

42

65-95

22

69-30

02

72-63

82

75-83

62

79-00

43

6600

23

69-35

03

72-65

83

75-85

63

79-03

44

66-05

24

69'40

04

72-70

84

75-90

64

7905

45

66-10

25

69-43

05

72-75

85

75-95

65

79-10

46

66-15

26

69-45

06

72-80

86

76-00

66

79-15

47

6620

27

6950

07

72-83

87

76-03

67

79-20

48

6623

28

69 55

08

72-85

88

76-05

68

79-23

49

66-25

29

6960

09

72-90

89

76-10

69

7925

1-4550

6630

1-4630

69 63

1-4710

7295

1-4790

76-15

1-4870

79-30

51

6635

31

69-65

11

73-00

91

7620

71

79-35

52

66-40

32

69'70

12

73-03

92

7623

72

79-40

53

66-43

33

69'75

13

73 '05

93

76-25

73

79-43

54

66-45

34

69-80

14

7310

94

76-30

74

79-45

55

66-50

35

69-83

15

73-15

95

76-35

75

79-50

56

66-55

36

69-85

16

73-20

96

76-40

76

79-53

57

6660

37

6990

17

7323

97

76-43

77

79-55

58

66-63

38

6995

18

7325

98

76-45

78

79-60

59

66-65

39

70-00

19

7330

99

76-50

79

79-63

1-4560

66-70

1-4640

70-05

1-4720

73-35

1-4800

76-55

1-4880

79-65

61

66-75

41

70-10

21

73-40

01

76-60

81

7970

62

66-80

42

70-15

22

73-43

02

76-63

82

79-75

63

66-83

43

70-20

23

73-45

03

76-65

83

79-80

64

66-85

44

70-23

24

73-50

04

76-70

84

79-83

566

APPENDIX.

TABLE OF DRY SUBSTANCE FROM EEFRACTIVE INDEX AT 28° C. — Continued.

Index.

Per Cent.
Dry Sub-
stance.

Index.

Per Cent.
Dry Sub-
stance.

Index.

Per Cent.
Dry Sub-
stance.

Index.

Per Cent.
Dry Sub-
stance.

Index.

Per Cent,
Dry Sub-
stance.

1-4885

79-85

1-4945

82-20

1-5005

84-50

1-5065

86*70

1-5125

88-93

86

79-90

46

82-23

06

84-53

66

86-75

26

88-95

87

79-95

47

82-25

07

84-55

67

86-80

27

89-00

88

80-00

48

82-30

08

84-60

68

86-83

28

89-03

89

80-03

49

82-35

09

84-63

69

86-85

29

89-05

1-4890

80-05

1-4950

82-40

1-5010

84-65

1-5070

86-90

1-5130

89-10

91

80-10

51

82-43

11

84-70

71

86-93

31

89-13

92

80-15

52

82-45

12

84-75

72

86-95

32

89-15

93

80-20

53

8250

13

84-80

73

87-00

33

89-20

94

80-23

54

82-53

14

84-83

74

87-03

34

89-23

95

8025

55

82-55

15

84-85

75

87-05

35

86-25

96

80-30

56

82-60

16

84-90

76

87-10

36

89-30

97

80-35

57

82-63

T7

84-93

77

87-15

37

89-35

98

8040

58

82'65

18

84-95

78

87-20

38

89-40

99

80-43

59

8270

19

85-00

79

87-23

39

89-43

1-4900

80-45

1-4960

82-75

1-5020

85-03

1-5080

87-25

1-5140

89-45

01

80-50

61

8280

21

85-05

81

87-30

41

89-50

02

80-53

62

82-83

22

8510

82

87-33

42

89-53

03

80-55

63

82-85

23

85-15

83

87-35

43

89-55

04

80-60

64

82-90

24

85-20

84

87-40

44

89-60

05

80-63

65

8295

25

85-23

85

87-45

45

8963

06

80-65

66

8300

26

85-25

86

87-50

46

89'65

07

80-70

67

8303

27

85-30

87

87-53

47

89-70

08

80-75

68

83-05

28

85-33

88

87'55

48

89-75

09

80-80

69

68*10

29

85-35

89

87-60

49

89-8Q

1-4910

80-83

1-4970

83-15

1-5030

85-40

1-5090

87-63

1-5150

89-83

11

80-85

71

83-20

31

85-45

91

87-65

51

89-85

12

8090

72

83-23

32

85-50

92

87-70

52

89-90

13

80-95

73

83-25

33

85-53

93

87-75

53

89'93

14

81-00

74

8330

34

85-55

94

87-80

54

89'95

15

81-03

75

83-35

35

85-60

95

87-83

55

90-00

16

81-05

76

8340

36

85-63

96

87-85

56

90-03

17

81-10

77

83-43

37

85-65

97

87-90

57

90-05

18

81-15

78

83-45

38

85-70

98

87-93

58

90-10

19

81-20

79

8350

39

85-75

99

87-95

59

90-13

1-4920

81-23

1-4980

83-53

1-5040

85-80

15100

88-00

1-5160

90-15

21

81-25

81

83-55

41

8583

01

88-03

61

9020

22

81-30

82

83-60

42

85-85

02

88-05

62

90-25

23

81-35

83

83-63

43

85-90

03

88-10

63

90-30

24

81-40

84

8365

44

8593

04

88-15

64

90-33

25

81-43

85

83-70

45

85-95

05

8820

65

90-35

26

81-45

86

83-75

46

86-00

06

88-23

66

90-40

27

81-50

87

83-80

47

86-03

07

88-25

67

90-43

28

81-53

88

83-83

48

86-05

08

88-30

68

90-45

29

81-55

89

8385

49

86-10

09

88-33

69

90-50

1-4930

81-60

1-4990

83-90

1-5050

86-15

1-5110

88-35

1-5170

90-53

31

81-63

91

83-95

51

86-20

11

88-40

71

90-55

32

81-65

92

84-00

52

86-23

12

88-45

72

90-60

33

81-70

93

84-03

53

86-25

13

88-50

73

90-63

34

81-75

94

84-05

54

86-30

14

8853

74

90-65

35

81-80

95

84'10

55

86-33

15

88-55

75

90-70

36

81-83

96

84-15

56

86-35

16

88-60

76

90'75

37

81-85

97

84-20

57

86-40

17

88-63

77

90-80

38

81-90

M

84-23

58

86-45

18

88'65

78

90-83

39

81-95

99

84-25

59

86-50

19

88-70

79

80-85

1-4940

8200

1-5000

84-30

1-5060

86-53

1-5120

88-75

1-5180

90-90

41

82-03

01

84-33

61

8655

21

8880

81

90-93

42

82-05

02

84-35

62

86-60

22

88-83

82

90-95

43

82-10

03

84-40

63

86-63

23

88-85

44

82-15

04

84-45

64

86-65

24

88-90

567

CANE SUGAR.

TABLE OF COEEECTIONS FOE THE TEMPEEATUEE.
DRY SUBSTANCE.

Temperature of
the prisms in

0

5

10

15

20

25

30

40

50

60

70

80

90

SUBTRACT.

20° 0

•53

•54

•55

•56

•57

•58

•60

•62

•64

•62

•61

•60

•58

21

•46

•47

•48

•49

•50

•51

•52

•54

•56

•54

•53

•52

•50

22

•40

•41

•42

•42

•43

•44

•45

•47

•48

•47

•46

•45

•44

23

•33

•33

•34

•35

•36

•37

•38

•39

•40

•39

•38

•38

•38

24

•26

•26

•27

•28

•28

•29

•30

•31

•32

•31

•31

•30

•30

25

•20

•20

•21

•21

•22

•22

•23

•23

•24

•23

•23

•23

•22

26

•12

•12

•13

•14

•14

•14

•15

•15

•16

•16

•16

•15

•14

27

•07

•07

•07

•07

•07

•07

•08

•08

•08

•08

•08

•08

•07

ADD.

29° 0

•07

•07

•07

•07

•07

•07

•08

•08

•08

•08

•08

•08

•07

30

•12

•12

•13

•14

•14

•14

•15

•15

•16

•16

•16

•15

•14

31

•20

•20

•21

•21

•22

•22

•23

•23

•24

•23

•23

•23

•22

32

•26

•26

•27

•28

•28

•29

•30

•31

•32

•31

•31

•30

•30

33

•33

•33

•34

•35

•36

•37

•38

•39

•40

•39

•38

•38

•38

34

•40

•41

•42

•42

•43

•44

•45

•47

•48

•47

•46

•45

•44

35

•46

•47

•48

•49

•50

•51

•52

•54

•56

•54

•53

•52

•50

Temperature.

TABLE OF THE DENSITY OF WATEE.

Temperature.

4 ....
10 .. .

Volume.
1-00000
;". -99974

55
60

Volume.
. . . -98579

•98331

15 ....

-99913

65 /. ..

•98067

20 .. .
25

. .. .... -99825
•99710

70
75 .... ..

. . . -97790
•97495

30 .. .

.• ... -_ -99571

80

.... -97191

35 ....

, -99410

85

. . -96876

40 .. .

-99233

90 ,,.

-96550

45 ....

.... .. -99035

95

. . -96212

50

•98813

100

•95803

568

APPENDIX.

TABLE OF THE

ELEVATION OF THE BOILING POINT OF SUGAR SOLUTIONS

(Claassen).

Per cent.
Sugar.

Elevation
of the
boiling point
F°

Per cent.
Sugar.

Elevation
of the
boiling point
F°

75-

13-2

86-75

31-1

75-5

13-7

87'

31-8

76-

14-2

87-25

32-5

76-5

14-8

87-5

33-2

77-

15-3

87-75

33-9

77-5

15-8

88-

34-6

78-

16-4

88-25

35-3

78-5

16-9

88-5

36-0

79-

17-5

88-75

36-7

79-5

18-0

89-

37-5

80-

18-6

89-25

38-3

80-5

19-3

89-5

39-1

81-

19-9

89-75

39-9

81-5

20-5

90-

40-7

82-

21-2

90-25

41-5

82-5

22-0

90-5

42-4

83-

22-7

90-75

43-2

83-5

23-6

91-

44-1

84-

24-7

91-25

45-1

84-5

25-7

91-5

46-3

So-

26-8

91-75

47-7

85-5

27-9

92-

50-2

86-

29-2

86-25

29-8

86-5

30-4

569

CANE SUGAR.

TABLE SHOWING THE EXPANSION OF SUGAE SOLUTIONS.

(Gerlach.)

Temperature

10 per cent.

20 per cent.

30 per cent.

40 per cent.

50 per cent.

0

1-0000

1-0000

1-0000

1-0000

1-0000

5

1-0004

1-0007

1-0009

1-0012

1-0016

10

1-0012

1-0016

1-0021

1-0026

1-0032

15

1-0021

1-0028

1-0034

1-0042

1-0050

20

1-0033

1-0041

1-0049

1-0058

1-0069

25

1-0048

1-0057

1-0066

1-0075

1-0088

30

1-0064

1-0074

1-0084

1-0094

1-0110

35

1-0082

1-0092

1.0103

1-0114

1-0132

40

1-0101

1-0112

1-0124

1-0136

1-0156

45

1-0122

1-0134

1-0146

1-0160

1-0180

50

1-0145

1-0156

1-0170

1-0184

1-0204

55

1-0170

1-0183

1-0196

' 1-0210

1-0229

60

1-0197

1-0209

1-0222

1-0235

1-0253

65

1-0225

1-0236

1-0249

1-0261

1-0278

70

1-0255

1-0265

1-0277

1-0287

1-0306

75

1-0284

1-0295

1-0306

T0316

1-0332

80

1-0316

1-0325

1-0335

1-0345

1-0360

85

1-0347

1-0355

1-0365

1-0375

1-0388

90

1-0379

1-0387

1-0395

1-0405

1-0417

95

1-0411

1-0418

1-0425

1-0435

1-0445

100

1-0442

1.0450

1-0456

1-0465

1-0477

570

APPENDIX.

W5U3T*«(Nas»CiO^«COF-l-»<

lO ^ ^O WS U5 ^O *O iQ CO CD CO CO CO

Oi-icot^oo^i^'*
Oi^<^WT*<i0^cbi^

CDCOCDCDCOCOCCCOCOCDCOCOt^t-

CD CO CO CO CO CO CO

CO CO CO CO CO t^ t--

571

CANE SUGAR.

EQUIVALENTS OF COPPER AND DEXTROSE FOR ALLIHN'S

METHOD.

Milli-
grams of
Copper.

Milli-
grams of
Dextrose.

Milli-
grams of
Copper.

Milli-
grams of
Dextrose.

Milli-
grams of
Copper.

Milli-
grams of
Dextrose.

Milli-
grams of
Copper.

Milli-
grams of
Dextrose.

11

6-6

41

21-4

71

36-3

101

51-4

12

7-1

42

21-9

72

36-8

102

51-9

13

7-6

43

22-4

73

37-3

103

52-4

14

8-1

44

22-9

74

37-8

104

52-9

15

8-6

45

23-4

75

38-3

105

53-5

16

9-0

46

23-9

76

38-8

106

54-0

17

9-5

47

24-4

77

39-3

107

54-5

18

10-0

48

24-9

78

39-8

108

55-0

19

10-5

49

25-4

79

40-3

109

55'5

20

11-0

50

25-9

80

40-8

110

56-0

21

11-5

51

26-4

81

41-3

111

56-5

22

12-0

52

26-9

82

41-8

112

57-0

23

12-5

53

27-4

83

42-3

113

57-5

24

13-0

54

27-9

84

42-8

114

58-0

25

13'5

55

28-4

85

43-4

115

58-6

26

14-0

56

28-8

86

43-9

116

59-1

27

14-5

57

29-3

87

44-4

117

59-6

28

15-0

58

29-8

88

44'9

118

60'1

29

15-5

59

30-3

89

45-4

119

60-6

30

16-0

60

30-8

90

45-9

120

61-1

31

16-5

61

31-3

91

46-4

121

61-6

32

17-0

62

31 8

92

46-9

122

62-1

33

17-5

63

32-3

93

47-4

123

62-6

34

18-0

64

32-8

94

47-9

124

63-1

35

18-5

65

33-3

95

48-4

125

63-7

36

18-9

66

33-8

96

48-9

126

64-2

37

19-4

67

34-3

97

49-4

127

64-7

38

19-9

68

34-8

98

49-9

128

65-2

39

20-4

69

35-3

99

50-4

129

65-7

40

20-9

70

35-8

100

50-9

130

66-2

572

APPENDIX.

EQUIVALENTS OF COPPER AND DEXTROSE FOR ALLIHN'S METHOD.— Continued.

Milli-
grams of
Copper.

Milli-
grams of
Dextrose.

Milli-
grams of
Copper.

Milli-
grams of
Dextrose.

Milli-
grams of
Copper.

Milli-
grams of
Dextrose.

Milli-
grams of
Copper.

Milli-
grams of
Dextrose.

131

66-7

166

84-8

201

103-1

236

121-7

132

67-2

167

85-3

202

103-7

237

122-3

133

67-7

168

85-9

203

104-2

238

122-8

134

68-2

169

86-4

204

104-7

239

123-4

135

68-8

170

86-9

205

105-3

240

123'9

136

69-3

171

87-4

206

105-8

241

124-4

137

69-8

172

87-9

207

106-3

242

125-0

138

70-3

173

88-5

208

106-8

243

125-5

139

70-8

174

89-0

209

107-4

244

126-0

140

71-3

175

89-5

210

107-9

245

126-6

141

71-8

176

90-0

211

108-4

246

127-1

142

72-3

177

90-5

212

109-0

247

127-6

143

72-9

178

91-1

213

109-5

248

128-1

144

73-4

179

91-6

214

1100

249

128-7

145

73-9

180

92-1

215

110-6

250

129-2

146

74-4

181

92-6

216

111-1

251

129-7

147

74-9

182

93-1

217

111-6

252

130-3

148

75-5

183

93-7

218

112-1

253

130-8

149

76-0

184

94-2

219

112-7

254

131-4

150

76-5

185

94-7

220

113-2

255

131-9

151

77-0

186

95-2

221

113-7

256

132-4

152

77-5

187

95-7

222

114-3

257

133-0

153

78-1

188

96-3

223

114-8

258

133-5

154

78-6

189

96-8

224

115-3

259

134-1

155

79-1

190

97-3

225

115-9

260

134-6

156

79-6

191

97-8

226

116-4

261

135-1

157

80-1

192

98-4

227

116-9

262

135-7

158

80-7

193

98-9

228

117-4

263

136-2

159

81-2

194

99-4

229

118-0

264

136-8

160

81-7

195

100-0

230

118-5

265

137-3

161

82-2

196

100-5

231

119-0

266

137-8

162

82-7

197

101-0

232

119-6

267

138-4

163

83-3

198

101-5

233

120-1

268

138-9

164

83-8

199

102-0

234

120-7

269

139-5

165

84-3

200

102-6

235

121-2

270

140-0

573

279

145-0

314

164-2

349

183-7 384 203-7

280

145-5

315

164-8

350

184-3

385

204-3

281

146-1

316

165-3

351

184-9

386

204-8 .

282

146-6

317

165-9

352

185-4

387

205-4

283

147-2

318

166-4

353

186-0

388

206-0

284

147-7

319

167-0

354

186-6

389

206-5

285

148-3

320

167-5

355

187-2

390

207-1

286

148-8

321

168-1

356

187-7

391

207-7

287

149-4

322

168-6

357

188-3

392

208-3

288

149-9

323

169-2

358

188-9

393

208-8

289

150-5

324

169-7

359

189-4

394

209-4

290

151-0

325

170-3

360

190-0

395

210-0

291

151-6

326

170-9

361

190-6

396

210-6

292

152-1

327

171-1

362

191-1

397

211-2

293

152-7

328

172-0

363

191-7

398

211-7

294

153-2

329

172-5

364

192-3

399

212-3

295

153-8

330

173-1

365

192-9

400

212-9

296

154-3

331

173-7

366

193-4

401

213-5

297

154-9

332

174-2

367

194-0

402

214-1

298

155-4

333

174-8

368

194-6

403

214-6

299

156-0

334

175-3

369

195-1

404

215-2

300

156-5

335

175-9

370

195-7

405

215-8

301

157'1

336

176-5

371

196-3

406

216-4

302

157-6

337

177-0

372

196-8

407

217-0

303

158-2

338

177-6

373

197-4

408

217-5

304

158-7

339

178-1

374

198-0

409

218-1

305

159-3

340

178-7

375

198-6

410

218-7

574

APPENDIX.

EQUIVALENTS OF COPPER AND DEXTROSE FOR ALLIHN'S METHOD.— Continued.

Milli-
grams of
Copper.

Milli-
grams of
Dextrose.

Milli-
grams of
Copper.

Milli-
grams of
Dextrose.

Milli-
grams of
Copper.

Milli-
grams of
Dextrose.

Milli-
grams of
Copper.

Milli-
grams of
Dextrose.

411

219-3

426

228-0

441

236-9

456

245-7

412
413

219-9
220-4

427

428

228-6
229-2

442

443

237-5
238-1

457

458

246-3
246-9

414

221-0

429

229-8

444

238-7

459

247-5

415

221-6

430

230-4

445

239-3

460

248-1

416

222-2

431

231-0

446

•
239-8

461

248-7

417

222-8

432

231-6

447

240-4

462

249-3

418

223-3

433

232-2

448

241-0

463

249-9

419

223-9

434

232-8

449

241-6

420

224-5

435

233-4

450

242-2

421

225-1

436

233-9

451

242-8

422

225-7

437

234-5

452

2434

423

226-3

438

235-1

453

244-0

424

226-9

439

235-7

454

244-6

425

227-5

440

236-3

455 245-2

575

CANE SUGAR.

SODIUM OAEBONATE AT 82-50° F.
(Schiff.)

Specific
Gravity.

Percentage
of Na2CO3
10HaO.

Percentage of
Na2C03.

Specific
Gravity.

Percentage
of Na2C03.
10H20.

Percentage of
Na2CO3.

1-0038

1

•370

1-1035

26

9-635

1-0076

2

•741

1-1076

27

10-005

1-0114

3

1-112

1-1117

28

10-376

1-0153

4

1-482

1-1158

29

10-746

1-0192

5

1-853

1-1210

30

11-118

1-0231

6

2-223

1-1242

31

11-448

1-0270

7

2-574

1-1284

32

11-859

1-0309

8

2-965

1-1326

33

12-230

1-0348

9

3-335

1-1368

34

12-600

1-0388

10

3-706

1-1410

35

12-971

1-0428

11

4-076

1-1452

36

13-341

1-0468

12

4-447

1-1494

37

13-712

1-0508

13

4-817

1-1536

38

14-082

1-0548

14

5-188

1-1578

39

14-453

1-0588

15

5-558

1-1620

40

14-824

1-0628

16

5-928

1-1662

41

15-195

1-0668

17

6-299

1-1704

42

15-566

1-0708

18

6-670

1-1746

43

15-936

1-0748

19

7-041

1-1788

44

16-307

1-0789

20

7-412

1-1830

45

16-677

1-0830

21

7-782

1-1873

46

17-048

1-0871

22

8-153

1-1916

47

17-418

1-0912

23

8-523

1-1959

48

17-789

1-0953

24

8-894

1-2002

49

18-159

1-0994

25

9-264

1-2045

50

18-530

576

APPENDIX.

CAUSTIC SODA AT 82 • 5° E.

(Geerligs.)

Percentage
of Soda.

Specific
Gravity of a
percentage
of Na20.

Specific
Gravity of a
percentage
of NaOH.

Percentage
of Soda.

Specific
Gravity of a
percentage
of Na2O.

Specific
Gravity of a
percentage
of NaOH.

1

1-012

1-009

31

1-434

1-339

2

1-027

1-020

32

1-446

1-347

3

1-040

1-032

33

1-458

1 -359

4

1-055

1-043

34

1-471

1-370

5

1-071

1-056

35

1-484

1-380

6

1-086

1-067

36

1-496

1-391

7

1-101

1-078

37

1-511

1-401

8

1-116

1-089

38

1-526

1-411

9

1-129

1-100

39

1-539

1-422

10

1-342

1-112

40

1-554

1-433

11

1-158

1-123

41

1-566

1-443

12

1-172

1-133

42

1-579

1-452

13

1-187

1-145

43

1-593

1-464

14

1-200

1-156

44

1-606

1-474

15

1-215

1-167

45

1-617

1-484

16

1-230

1-178

46

1-632

1-495

17

1-241

1-184

47

1-645

1-503

1»

1-254

1-198

48

1-658

1-514

19

1-266

1-209

49

1-673

1-524

20

1-284

. 1-221

50

1-685

1-535

21

1-296

1-234

51

1-700

1-545

22

1-311

1-243

52

1-714

1-555

23

1-325

1-254

53

1-725

1-565

24

1-337

1-265

54

1-740

1-575

25

1-351

1-275

55

1-755

1-586

26

1-365

1-286

56

1-770

1-596

27

1-374

1-296

57

1-780

1-606

28

1-391

1-306

58

1-795

1-617

29

1-406

1-317

59

1-810

1-628

30

1-420

1-328

60

1-825

1-638

577

37

CANE SUGAR.

TABLE SHOWING THE SOLUBILITY OF SUGAE IN WATEE.

(Herzfeld.)

Temperature.
C°.

Sugar
per cent.

Temperature.
C°.

Sugar
per cent.

Temperature.
C°.

Sugar
per cent.

0

64-18

35

69-55

70

76-22

5

64-87

40

70-42

75

77-27

10

65-58

45

71-32

80

78-36

15

66-53

50

72-25

85

79-46

20

67-09

55

73-20

90

80-61

25

67-89

60

74-18

95

81-77

30

68-80

65

75-88

100

82-97

TABLE SHOWING THE SOLUBILITY OF LIME IN SUGAE

SOLUTIONS.

Sugar in
100 parts of
Water.

Density of
Syrup.

Density after
Saturation with
Lime.

Residue dried at
120° C.
Per cent, of Lime.

Residue dried at
120° C.
Per cent, of Sugar.

5

1-018

1-026

15-3

84-7

10

•036

1-053

18-1

81-9

15

•052

1-080

18-5

81-5

20

•068

1-104

18-8

81-2

25

•082

1-128

19-8

80-2

30

•096

1-148

20-1

79-9

35

•110

1-166

20-5

79-5

40

1-122

1-179

21-0

79-0

TABLE SHOWING THE

SOLUBILITY OF SALTS IN SUGAE SOLUTIONS.
(Jacobsthal.)

Solution containing

5% Sugar.

10% Sugar.

15% Sugar.

20% Sugar.

25% Sugar.

Grams.

Grams.

Grams.

Grams.

Grams.

Calcium sulphate .....

2-095

1-946

1-593

1-539

1-333

,, carbonate

0-027

0-036

0-024

0-022 0-008

„ oxalate

0-033

0-047

0-012

0-008 0-001

,, phosphate

0-029

0-028

0-014

0-018

0-005

,, citrate

1-813

1-578

1-505

1-454

1-454

Magnes. carbonate

0-317

0-199

0-194

0-213

0-284

578

ADDITIONAL NOTES EELATING TO CERTAIN PORTIONS
OF THE TEXT.

Page 25.

Loethers Cane.— Mr. Prinsen Geerligs has informed the author that, at the
outbreak of ' sereh ' in Java the late Dr. Soltwedel introduced canes from all
parts of the world in the search for an immune variety ; among those from
Mauritius was one, the label attached to which was read ' Loethers,' and after-
wards it was surmised that 'Loethers' was a misreading for ' Louzier,' and in
the Java literature the expression * Loethers (Louzier}' frequently occurs. Now
the cane illustrated by Soltwedel as Loethers bears no resemblance to the Louzier
of Mauritius, the Bourbon of Demerara, the Lahaina of Hawaii, or the Otaheite
of Cuba, whereas in all these four districts its characteristics are maintained
unaltered. In addition, M. Auguste de Vilelle, to whom the author showed the
drawing of Loethers in Soltwedel's portfolio of canes, at once recognized the cane
as the ' Tamarind ' of Mauritius. Admitting that canes may change their
appearance widely under different climatological and soil conditions, the author
is yet inclined to believe that the canes as sent must have been mislabelled. The
Otaheite cane still remains of so great a value that a knowledge of its identity
in all sugar districts is of great importance.

With regard to the Tibboo teelor cane mentioned on page 29, Mr. Geerligs
states that ' teelor = egg ' refers to the appearance of the flower, which in this
cane does not develop, but remains a thick mass, resembling a cauliflower ; it is
eaten, cooked or pickled by the natives.

Page 32.

Tip Canes. — The striped and yellow tip canes are very similar to those
known in Mauritius as branchu rayee and branchu blanche.

Paye 32.

TJba Cane. — It was not until this book was in the press that the author had
an opportunity of examining a specimen of this cane. It is a greenish cane, of
slender habit, the diameter of the internodes being about f inch. The internodesr
averaging 6 inches, are very long in proportion to girth. The proportion of rind
tissue is high, and a well-marked fistula occurs in the centre of the stalk. The
nodes are swollen and the eyes are prominent; superficially, the dissimilarity from
the Otaheite type of cane is so great as to suggest that on examination a system-
atist would separate this cane from the species Saccharum officinarum. A very
good idea of the appearance of this cane can be obtained on inspecting the
illustration of S. glonggony in Soltwedel's Formen und Farben S. officinarum.

Page 83.

Green Manuring-.— It should be mentioned that some plants other than the
leguminosae have bacterial nodules associated with their roots; it is not known yet
whether these plants will have any value as green soilers, and for the present it is
the leguminosae alone which need be considered.

579

CANE SUGAR.

Page 87.

Demerara Soils.— Keference may be made to two able articles on this subject
appearing in The International Sugar Journal, April and May, 1910.

Page 138.

Fungus Diseases.— A very large number of fungi associated with the cane
in South America have been described by Spegazzini in the Revista Agricola y
Veterinaria, La Plata, and in other Latin- American journals. The author has
never had access to these publications.

Page lJf.8.

Thielaviopsis ethaceticus. — According to Patterson, Charles and Veihmeyer
(Bull. 171, Bureau of Plant Industry, U.S.D.A.) this fungus was first described
by De Seynes in 1886, as Sporoschisma paradoxum ; in 1892, Saccardo renamed it
Chalara paradoxa ; it was in 1893 that Went described it as Thielaviopsis
ethaceticus, and in 1904 Hohnel recognized the identity of the fungus. Hence,
following the usually accepted system of nomenclature this fungus should be
referred to as Thielaviopsis paradoxa. This organism is also the cause of dangerous
rots of the pine-apple. The name ' Pine-apple disease,' attached to its manifesta-
tions on the sugar cane, is purely fortuitous, and is not connected with its faculty
of attacking pine-apples.

Page 359.

Pan Control. - The electrical recording thermometers mentioned on page 424,
as a means of controlling the combustion in the furnace, would form an ideal
means of controlling the temperature in and during the whole operation of pan
boiling ; such apparatus is already in use in the not very dissimilar industry of
jam boiling.

Page ^.

Invertase. — The action of invertase extracted from yeast has very recently
"been studied in great detail by C. S. Hudson. — See Jour. Indus, and A pp. Chem.,
Vol. II., page 143, and also a series of articles in the Jour. Am. Chem. Soc.,
during 1909 and 1910.

Page £75.

Fibre. — The determination of fibre in sugar house control has special
significance, and includes everything which is not juice. As employed in factory
work it must be carefully distinguished from ' crude fibre' or ' digestible fibre'
of plant physiology and analysis. Forming as it does the basis of the control of
mill work, a method simulating the action of mills should be followed ; the most
convenient method the writer knows of is to finely divide the cane, place a sample
in a linen bag and squeeze out as much juice as possible in a powerful press ; the
bag is removed from the press, the cake of fibre opened out by rubbing without
removing from the bag, soaked in cold water and again pressed. This operation
is repeated until the expressed juice is free from soluble solids ; this will take not
more than six pressings, after which the residue, consisting of ' fibre,' is dried
and weighed. In the absence of a press, washing of the finely divided sample in
running cold water should be adopted.

580

INDEX.

Subject Matter.

A.

B.

PAGE

Absolute Juice 223

Added Water 497

Aerial Ropeways 162, 163

Air, Effect of, in Vacuum Pumps 329

Albumenoids 15

,, Determination of 481

Alcoholometiy 538

Alinit 81

Amides 15

,, Determination of 481

Analysis of Cane 475

,, Filter Press Cake 487

„ Flue Gases 421

„ Juices 479

,, Lime 489

,, Limestone .. .. 488

,, Massecuites 483

Megass 477

,, Molasses 483

Sugars 487

Wash 540

Waste Waters .. .. 488

Analytical Processes, Allihn's .. 459

,, ,, Browne's .. .. 456, 463

,, „ Clerget's 453

,, „ Creydt's 457

„ „ Direct Polarization.. 453

„ ., Double „ .. 454

,, „ Dupont's 485

,, „ Electrolytic 461

„ ,, Feliling's 464

,, ,, Home's 448

,, ,, lodometric 462

,, ,, Mun son & Walker's.. 459

Pavy's 466

„ ,, Permanganate 462

., ,, Peska's 467

,, ,, Pieraert's 457

„ „ Romijn's 469

„ „ Sidersky's 462

Soldaini's 467

„ „ Vivien's 485

„ ,, Wortmann's 457

,, ,, Zamaron's 448

Ascherontia allyrodis 135

Ash of Cane 75

,, in relation to Manuring.. .. 76

Assay of Albumenoids 481

Alcohol 541

,, Amides 481

,, Cane Sugar 487

„ Crystallized Sugar 485

,, Dextrose 469

Fibre 475

,, Glucose 468

„ Gums 482

„ Levulose 469

„ Nitrogen 480

Reducing Sugars 467

Attenuation 540

Available Sugar 508

Azotobacter chroococcum 82

PAGE

Bac Portal 242

Bacteria in Distillery 517

„ in Soil 81

„ in Sugar house 517

Ball Bearings 375

Barbados, Harvest Time in 124

„ Manurial Experiments in .. .. 59

„ Seedling Canes of 40

Bibit Gardens 117

Boilers, Choice of 406

„ Heating Surface of 409

Smoke Tube 404

Water Tube 405

Boiling House, Control of 508-

Bordeaux Mixture 155

Brasmoscope 361

British Guiana, Cultivation in 109

Harvest Time in 124

Irrigation in 95

Manurial Experiments in 55

Manuring in 74

Rum Making in 520

Seedling Canes of 40

Soils of 48

Yeasts of 516

British Thermal Unit 283

Brix Hydrometer 471

Burette . .

C.

Calorie 283

Cane, Abnormalities in 127

„ Amides of 15

„ Analysis of .. , 475

„ Arrowing of 4, 19

„ Ash of 75

„ „ in Relation to Manuring .. 76

„ Botanical Position of 1

„ Carriers for 198

„ Chemical Selection of 125

„ Climate Suited for 18

,, Composition of 13

„ Continuous Growth of 123

„ Control of Weight of 492, 498

„ Cultivation of, in British Guiana.,109, 118

„ Cuba 112, 119

„ „ Hawaii 114, 119

„ „ „ Java 114

„ Louisiana .. 112, 118

„ „ „ Straits Settlements 120

„ „ „ by Reynoso System. 116

„ „ „ „ Zayas System ... 116

„ Cutting Back of 124

„ Degenerescence of 145, 157

,, Deterioration of Cut 168

,, Distribution of Sugar in 14

„ Effect of Humidity on 18

„ Effect of Manuring on 64

„ Effect of Rainfall on 20

,, Effect of Wind on 20

„ Experimental Manuring of.. .. 55, 63

581

INDEX.

PAGE

Cane,- Eye of 2

„ Fibreof 16

„ Flower of

,, Flowering of 4,

„ Formation of Sugar iu

4

124
10

Geographical Limits of Cultivation . .

Gums of 16

Harvest Time of 124

Harvesting of 159

Immune Varieties of 156

Internodes of 2, 14

Irrigation of, in British Guiana .. 95

„ Cuba 95

Egypt 95

„ Hawaii 91

„ Java 95

,. Mauritius 94

Peru 93

„ Leaf of 3

,, Lecithins of 16

„ Loading of 160

„ Manuring, Practice of, in British

Guiana.. .. 74

„ „ Hawaii .. .. 74

„ „ „ Java 74

,, Louisiana .. 75

„ „ Mauritius .... 75

,, Nitrogenous Bodies of 15

„ Nodes of 2, 14

,, Nurseries for 117

,, Physiology of 10

„ Preparation of Land for Planting .. 107

„ Ratoonage of 123

„ Reducing Sugars of 15

„ Rind of 3

„ Roots of 3

,, Sampling of 475

,, Seed, Source of .. 117

„ „ Quantity required per Acre .. 116

,. Seedlings 38

„ Sports of 36

„ Stalk of 2

„ Structure of 5, 7, 8

„ „ as affecting Milling .. .. 222

,, Sugar, Content of 13

„ Temperature Effect on 2, 19

,, Transpoi't of 161

,, Trashing of 121

„ Unloading of 166

„ Variation in 36

„ Water Transpired by 96

„ Wax of 16

„ Wrapping of 122, 123

„ Xan thine Bases of 16

•Canes of Barbados 40

„ Brazil 36

,, Demerara 40

Hawaii 36

India 33

„ Java 34, 41

Mauritius 41

„ New Guinea 35

,, Pacific Islands 35

Caramel 538

€arbonation, Chemistry of 263

„ Double 262

„ Effect of, on Manufacture .. 263

„ Tanks 266

Review of 271

„ Single 262

PAGE

Carriers for Cane 198

„ Megass 198

Centrifugals, Belt Driven 373

„ Capacity of 379

„ Control of 385

Electric 377

Friction 372

,, Hepworth's 376

Patterson's 381

„ Pivoted 373

Size of 379

„ Suspended 373, 376

Water-Driven 377

,, Weston's 373

Clarification, Action of Lime in 246

,, Agents proposed for 250

Continuous 242

Deming's 258

„ Hatton's 243

,, Hydrosulphite in 252

,, Lime required for 245

„ Methods of 241

„ Oxalic Acid in 250

,, Phosphoric Acid in 250

„ Increase in Purity due to .. 260

Soda in 250

Sulphur in 247-250

White and Yellow Sugar for 252

Clarifiers 242

Climate, Effect of, on Cane 18

„ „ „ Soils 47

,, and Varieties 21

Clostridium Pastorianum 82

Concretor 286

Condensers 325

„ Central 326

Control of Added Water 505

„ Boiling House 508

Cane Weights 498

,, Centrifugals 510

,, Diseases 155

Distillery 539

„ Entrainment 306, 210

,, Fermentation 540

Fuel 422

Mills 504

Pests 132

,, Vacuum Pan 359, 510

Weight of Juice 497

Weight of Megass 496

Cooling Towers 335

Crushers 190

Crystallization in Motion, Bock System .. 358

„ ,, Control of 359

„ „ Exhausted Molasses

in 356

„ „ First Sugar and

Molasses System.. 358
,, ,, Java Process .. .. 357
,, ,, of Low Products .. 359
,, ,. in Rapidity of Cool-
ing, Effect of .. 368
,, ,, Effect of Size of

Grain in 368

„ ,, Technique of — 359

,, ,, Theory of 355

,, ,, Unexhausted Molas-
ses in 357

Crystallizers, Capacity required 359

Huch's . 370

582

INDEX.

PAGE

Crystallizers, Ragot & Tourneur's 370

„ Shape of 369

Water-cooled 369

Cuba, Cultivation in 112, 119

„ Harvest Time in 124

,, Irrigation in 95

., Soils of 52

,, Sugar Production per Acre 124

Yeasts of.. 516

D.

Dansyz Virus 135

Diffusion and Milling compared 235

Batteiy 229

Cell 227

„ Cells, Influence of Number of .. 234

Cutters for 225

„ Meichage in 230

Method of Working 229

Dilution 501

Diseases, Acid Hot 142

,, Allantospora radicola 155

,, Ananas 148

,, Bacillus glangae 146

„ „ pseudarabinus 145

,, „ sacchari 146

Black Rot 140

„ „ Smut 142

„ Spot 140

,, ,, Brown Spot .. 141

,, Cercospora acerosum 140

„ ,, kopkei 138

,, „ longipes 141

?) ,, sacchari 139

„ „ vaginae 141

Cladosporium javanicum 155

Coleroa sacchari 140

Colletotrichum falcatum .. 147, 152

Coniothryrium melasporum .. 151
Continuous Growth of Cane and

88, 156

Control of 155

Cytospora sacchari 150

Diplodia cacaoicola 150

Djamoer oepas 138

Donkelan ziekte 142

Epidemics of 156

Eriosphaeria sacchari 140

Eye Spot 139, 141

Gumming 144, 151

Leaf Splitting 140

Leaf Spot 139

Leptosphaeria sacchari 140

Marasmius plicatus 143

„ sacchari 143

Melanconium sacchari 152

Mycosphaerella striatiformans . . 140

Pestalozzia fucescens 139

Pineapple 148

Pokka bong 143

Pseudomonas vascularum — 144

Red Rot 141, 147

Red Spot 140

Red String 145

Rind Fungus 152

Ring Spot 140

Root Fungus 143, 154

Rust . . 139

PAGE

Diseases, Sereh 145

„ Sphaeronoema adiposum . .. 151

„ Thielaviopsis ethaceticus 148

„ Top Rot 143

„ Tiicosphaeria sacchari 152

Ureda Kiihnii 139

,, Uromyces Kiihnii 139

., Ustilago sacchari 142

„ Yellow Spot 138

„ Yellow Stripe 141

Distillation, Control of 539

„ Practice of 530

Distilleries, Grain 522

Molasses 526

306,

E.

Egypt, Irrigation in

„ Harvest Time in

,, Manuring in

„ Soils of

Entrainment, Causes of . . . .

„ Control of

„ Loss of Sugar in

Erhmanite

Evaporation from Exposed Surfaces . .

Self

„ Theory of

Evaporators, Aspinall's

Capacity of

Chapman's

Circulation in

Condensers for

Efficiency of

Express

Extra Steam from

Film 290. 293,

Fryer's

Hagemann's

Heating Surfaces of

Horizontal Tube

Kestner's

Lillie's

Loss of Heat from

Multiple

Newall's

Pauly's

Picard's

Pre-

Scale in

Standard

Stillman's

Submerged Tube

Swenson's

Temperatures in

Transmission of; Heat in ..

Vertical Tube

Welner-Jelinek

Witcowitz's

Yaryan's

Zaremba's ..

95

124

75

49

Extra Steam

510
309
250
20
310
310
288
317
293
306
326
313
304
318
301
288
291

301
299
323
287
292
318
320
318

290

315

295
302
298
296
316

F.

False Grain 347

Faulty Rum 519

Fermentation 517

Alcoholic .. 518

583

INDEX.

PAGE

Fermentation, Butyric 518

„ Gumming 518

„ Lactic 517

Nitric 518

„ Viscous 518

„ in Grain Distilleries 322

,, in Molasses „ 526

Fibre, Assay of 475

„ Composition of 16

„ Fuel Value of 410

,, in Milling, Theory of 201

Field Ledger 126

Film Evaporation 298,301, 305

Filters, Bag 275

„ Frame 275

„ Mechanical 279

Taylor 275

Sand 280

Stocking 275

Filter Mud, Composition of 281

„ Manurial Value of 79

Filtration, Difficulties in 277

Double 277

„ Druelle Say 385

„ Loss of Sugar 27-7

„ Mechanical 279

,, Media used in 281

,, Sand 280

,, Wire Gauze 283

First Sugar and Molasses 358

Flue Gases, Analysis of 421

„ Heat lost in 414

Flumes 166

Forking Banks 118

Fuel, Control of 420

,, Megass as 408

„ Molasses as 420

,, Cane Straw as 420

Fuels, Heat Values of 420

Fungicides 155

Furnaces, Abell's 406

„ Dutch Oven 406

Godillot's 407

„ Grate Area of.. ... . .409

G.

Gas Washer 267

Gearing 181

Glucose, Action of Lime on 262

„ in Molasses, Effect of 393

„ Ash Ratio 395

Assay of 468

„ Non-Sugar Ratio 395

„ Optical Constants of 453

Glycocoll 16

Grimpage 314

Guanine 16

Guano 73

Gums 16

H.

Harrows 106

Harvesting of Cane 159

Hawaii, Canes of 36

Cultivation in 114, 119

„ Harvest Time in 124

M Irrigation in 91

Manurial Experiments in .... 61

PAGE

Hawaii, Soils of 47

„ Sugar Produced per acre .. .. 124

Windbreaks in 21

Heat, Consumption of. in Factories . . . . 416

„ Latent 283

„ Lost in Evaporators 323

,, „ Flue Gases 414

„ „ Steam Pipes 417

„ Transmission of 283

„ Unit of 283

Heating Surface of Boilers 409

„ ,, Evaporators 320

„ „ Vacuum Pans 348

Huillard Dryer 419

Humidity 18, 98

Hydrofluoric Acid in Distilleries . . 523, 532

Hydraulic Regulators 195

Hydrometers 471

Imbibition 202

Incondensible Gases 302, 332

India, Canes of 2, 33

„ Harvest Time in 124

„ Rotations in 87

Indicators 254

Insecticides 134

Inversion 255

Irrigation, Cost of 100

in British Guiana 95

in Cuba 94

in Egypt 95

„ in Hawaii 91

, , in Java 95

„ in Mauritius 94

., in Peru 93

,, Optimum Quantity of 100

„ Water, Quantity of 98

,, Water, Quantity used 91

J.

Java, Canes of 34

,, Cultivation in 114

,, Harvest Time in 124

„ Irrigation in 95

, , Manurial Experiments in 74

,, Rotations in 87

,, Rum Manufacture in 520, 525

„ Seedling Canes of 41

„ Soils of 53

„ Yeast of 515

Juice, Analysis of 479

„ Carbon ation of 262

,, Clarification of 241

„ Colour Reactions 253

„ Heaters for 244

,, Measurement of 498

,, Sampling of 508

,, Theory of Extraction of, by Mills.. 205

„ Weighing of 499

L.

Lamps for Polariscopes 439

Lecithins 16

Leguminous Crops 83

Levulose, Assay of 469

584

INDEX.

PAGE

Levulose : Dextrose, Ratio of 463

„ Optical Constants of 452

Lime, Analysis of 495

„ Burning of 269

„ Choice of 245

,, in Clarification, Effect of 246

„ Manurial Action of 56

., Magnesia Ratio 70

„ on Glucose, Action of 263

Limekilns 267

Limestones, Analysis of 269

Louisiana, Cultivation in 112

Green Manuring in 84

„ Harvest Time in 124

„ Manuring in 75

,, Rotations in 87

Soils of 50

Low Sugars, Return of 340

„ Suppression of 340

M.

Maceration 202

Manufacturing Processes, Besson's 251

„ „ Deming 258

. ,. „ Druelle-Say 385

„ „ Duchaissing's.. .. 202

„ „ Gans' 251

,, „ Geerligs-Hamakers 240

„ „ Hlavati's 251

„ ,, Kessler's 236

,. ,, Naudet's 238

,, ,, Perichon 238

„ ,, Russel-Risieii 202

„ Rousselot's .. .. 202

Manure, Ammonia as 55,56,59, 62

„ Application of 65, 67

Basic Slag as 56,57,72, 73

Blood as 56, 73

„ Cottonseed Cake as 72, 75

„ Cyanamide as 73

„ Filter Press Cake as 79

„ Fish Scrap as 73

Green 83

„ Guano as 55, 73

,, Gypsum as 73

,, Kainit as 74

„ Lime as 56, 69

,, Megass Ash as 76

,, Molasses as 402

,, Nitrate of Lime as 73

Nitrate of Potash as .. 72

,, Nitrate of Soda as .. 55, 56, 57, 60, 72

,, Distinction between Nitrogenous 71

,, Pen 88

Phosphates as .. ..55,56,57,61, 73

,, Potash as 72

Specific Effect of 64, 71

,, Superphosphate as 56

,, Tankage as 73

„ Valuation of 68

., Waste Products as 77

Manuring, Ash of Cane in relation to . . 75

,, Effect of, on Composition of Cane 64

Manurial Experiments in Barbados . . . . 59
,, ,, British Guiana,

55, 56, 57, 58

Hawaii .. 61,62, 63

„ Java 64

PAGE

Manurial Experiments in Mauritius . . . . 60

,, Practice in British Guiana 74

Egypt 75

., Hawaii 74

Java 74

„ „ Louisiana 75

Mauritius .. .. 75, 402

Massecuites, Analysis of 490

Sampling of 509

„ Transport of 371

Mauritius, Cultivation in 114

„ Green Manuring in 83

Harvest Time in 124

Irrigation in 94

„ Manurial Experiments in — 60

Practice in . . . . 75, 402

,, Seedling Canes of 41

Yeast of 520

Megass, Analysis of 484

„ As Manure, Ash of 76

Carriers for 198

„ Combustion of 411

„ Driers for 418

Fuel Value of 420

„ Furnaces for 406

,, Paper from 424

,, Products of Combustion of .. .. 411

„ Sampling of 509

Stoking of 408

Thermal Value of 410

Meichage 230

Milling, Preparation of Cane for 190

Theory of 205

Mill Rollers, Grooving of 200

,, „ Opening between 198

,, „ Proportions of 188

Surface Speed of 200

Mills, Allan's 174

„ Capacity of 199

„ Control of 510

Delbert's 175

De Mornay's 178

Evolution of 171

External Bolt Type 175

Fifteen Roller 170, 179

Five Roller 179

Fogarty's 177

Forced Feed in 193

Four Roller 178

Gearing of 181

Hall's .. .. 176

Inclined Bolt Type 174

Krajewski-Pesant 175

Motive Power for 180

Nine Roller 170, 179

Open Headstock Type 171

Pressure Regulators for 194

Rigid 173

Solid Headstock Type 173

Stillman's 174

Three Roller 171

Trash Turner for 182

Twelve Roller 170, 179

Two Roller 177

Montjus 250

Molascuit, Fermentation of 518

„ Food Value of 402

„ Manufacture of 401

Molasses, Alcohol from 402, 540

„ Analysis of 483

585

INDEX.

PAGE

Molasses, Composition of 392

„ Disposal of 400

,, Extraction of Sugar from 398

,, Food Value of 401

Formation of 388-392

„ Fuel Value of 402, 420

,, Glucose, Ash Ratio in 395

,, Glucose : Non-Sugar Ratio in .. 396

,, Return of 356

Sampling of 504

Solubility of, in'Sugar 389

„ Theory of 388

N.

Natal, Yeasts of 516, 526

Nicol, Prism 428

Nitrification 82

Nitrites 82

Nitrobacter 82

Nitrosococcus 82

Nitrosomonas 82

Normal Weight 433

O.

Obscuration 536

Off Barring 118

Optical Activity 427

„ Constants of Sugars 453

Osmosis . 397

P.

Pacific Islands, Canes of 35

Parasitization 135

Pectin 16

Pentosans 15

Peru, Harvest Time in 124

„ Irrigation in 93

„ Soils of 51

,, Sugar Production per acre 125

„ Yeast of 516

Pests of Cane, Acarid 132

,, „ Anerastia ablutella .. .. 129

Ants 132

,, ,, Aphis 131

Apogonia destructor
Army worm .. ..

Borers

Bud worms .. ..

Cane fly

Castnia licus .. ..
Chilo Auricilia
Chilo Infuscatellus ,
Chilo Simplex . .
Coleopterous ,

128,

130
130
130
128
131
129
129
128
129
130

Control of 132

Crickets 132

Dactylopius 131

Delphax Saccharivora — 131

Diaprepes Abbreviatus .. 130

Diatraea Saccharalis — 129

Diatraea Striatalis . . . . 129

Frog Hopper 131

Grapholitha Schistaceana.. 128

Gryllotalpa Africana 132

Hares . . . . 127

Heterodera Javanica .... 132

Hispella Wakkeri 131

Pests of Cane, Holanaria Picescens

,, „ Hoppers

,, ,, Jackals

„ ,, Leaf Hopper

,, ,, Leaf Miner

,, ,, Leucania Unipuncta ..

„ ,, Lepidoderma Albohirta.. .

,, ,, Lepidopterous

,, ,, Ligyrus Rugiceps

,, ,, Mammalian

,, ,, Microlepidopterous

„ Mites

,, ,, Moth Borers

„ ,, Nonagria Uniformis .. .

„ „ Oregma Lanigera

,, ,, Orthopterous

,, „ Parasitization of

„ ,, Perkinsiellia Saccharicida

,, „ Polyocha Saccharella ...

,, ,, Pou-a-Poche Blanche .. .

„ ,, Rats

,, ,, Rhyncotous

,, ,, Scapteriscus Didactylus . . .

., ,, Scirpophaga Auriflua .. .

„ ,, Scirpophaga Crysorrhola .

,, „ Scirpophaga Intacta

,, „ Scirpophaga Monostigma .

,. ,, Sesamia Nonagrioides ...

,, ,, Shot Borer

., ,, Spenophorus Obscurus

., ,, Spenophorus Sericeus ...

Spittle Fly

,, Tarsonymus Bankroftii . . .
,, ,, Termes Taprobaues

„ „ Tomaspis Posticata

„ Tylencus Sacchari

„ ,, Xyleborus Perforans

Pipette

Ploughs, Disc

,, Mould Board

,, for Cane, Special

,, Steam

,, Turn

Poisons

Polariscope, Adjustment of

Bates' .. .

Brock's

„ Colour

„ Compensators of .. ..

„ Control of , .,

,, Cornu's

File's

,, Half Shadow

,, Horsin-Deon's

Jellet's

,, Lamps for

,, Laurent's

,, Lippich's

„ Peter's

„ Schmidt & Haensch . .

,, Soleil-Duboscq

Soleil-Ventzke-Scheibler . .

„ Trannin

Transition Tint

Triple Field

Tubes for

Wild's

Press Cake, Analysis of

„ ,, Composition of

Manurial Value of

I.". I

PAGE

. 131

. 131

. 127

. 131

. 131

. 130

. 130

. 130

. 130

. 127

. 128

. 131

. 130

. 129

. 131

. 132

. 135

. 131

. 129

. 131

. 127

. 131

. 132

. 128

. 128

. 128

. 128

. 129

. 131

. 130

. 130

. 131

. 132

. 132

. 131

. 132

. 131

. 513

. 105

. 104

. 106

. 105

. 104

. 133

. 445

. 437

. 433

. 430

, 444

. 443

, 430

, 436

430

. 432

, 430

439

432

431

436

435

438

438

433

430

439

441

433

487

281

79

686

INDEX,

Proof Spirit

Pumping in Hawaii

Pumps, Blancke's

„ Calculation relating to

,, Carbonic Acid

„ Edwards'

Filter Press

„ Horizontal

,, Magma

Size of

>, Torpedo

,, Vacuum

Vertical

Wegelin's

Purity.
Pyrethrum

Q.

Quarantine

Queensland, Harvest Time in
Soils of .

R.

-ilo,

Raggi

Ralentisseurs

Ratoons

Reducing Sugars, Dextrose Ratio of ....

Revolving Knives

Reynoso System ,

Rotation of Crops 63, 86

Rotations of Sugars, Specific

Ruissellement

Rum, Colouring of

Composition of

Definition of . . . .

Faulty

Flavour of

Manufacture of, in British Guiana..

,, ,, Java

„ ,, Jamaica

„ Mauritius .

S.

135
124
53

521
306
122
463
190
116
134
453
305
535
523
523
519
526
520
521
522
521

Saccharates

Saccharomyces

Salt on Cane Soils, Effect of .

Sampling of Cane

„ Juices

Massecuites

„ Megass

„ Molasses .. ..

„ Press Cake .. .

,, Sugars

,, Syrups

Saturation

,, Economic Limit of
Scale, Composition of

„ Formation of

„ Polariscope

,, Removal of

Secherie

Seed Cane, Quantity Required
,. „ Source of .. ..

Seed Grain

Seedlings, Barbados

British Guiana..

515
46
475
502
503
503
504
504
504
503
202
212
337
335
434
336
419
116
117
346
40
40

PAGE PAGE

. 538 Seedlings, Hybrid 39

. 93 , History of 38

. 330 , Java 41

. 331 , Mauritius 41

. 270 , Methods used to obtain .... 39

. 329 , Resultsfrom 39

. 277 Selection of Cane, Chemical 123

. 327 Selective Harvesting 123

. 371 Shredders 192

. 331 Soil, Acidic 48, 51

. 327 „ Bacterial Action in 81

. 327 ,, Basic '48, 51

. 327 ,, Calcareous 49

. 329 „ Denitrification in 81

, 480 i, Effect of, on Cane 45

,134 ,, Lime : Magnesia Ratio in 70

Soils of British Guiana 48

Cuba 52

„ Egypt 49

„ Hawaii 47

Java 53

,, Louisiana 50

„ Peru 51

„ Queensland 53

Steam in Factory, Consumption of .. .. 416

Latent Heat of 284

,, Properties of 282

,, Superheated 285

Stills, Coffey's 530

,, Continuous 530

„ Coupler's 530

„ Vat 529

Stocktakings 511

Strainers 198

Straits Settlements, Cultivation in .. .. 120

Sugar, Assay of 447

„ Available 508

, , Inversion of 255

„ Optical Constants of 453

,, Specific Rotation of 453

„ Tests for 485

Sugar-boiling, Theory of 346

Sugars, Analysis of 487

Composition of 387

„ Conveyance of 382

Deterioration of 383, 519

Dextrose Ratio of 463

. „ Driers for 385

„ Fermentation of 520

„ Heat of Combustion of 413

Infection of 391

Return of Low 340

Suppression of Low 340

Storage of 383

Washing of 379

White and Yellow 252

Sulphur 247

Oven 247

Supersaturation 351

„ Control of 367

Syrup, Classification of 380

„ Sampling of 502

T.

Temperature, Effect of, on Cane .. .. 2, 19

Thermal Unit 283

Thermal Value of Cane Straw 420

Fuels.. . 420

587

INDEX.

Thermal Value of Megass

„ Molasses

„ Sugars

Toggle Gear

Transmission of Heat

Transport of Cane by Aerial Railways . . .
,, ,, Animal Power .

„ ,, Canals

,, ,, Flumes

„ . , Railroads

• „ ,, Roads

„ „ Traction Engines

Water

Trash, Burning of

,. Turner, Function lof

., ,, Theory of

Trashing of Cane

Trinidad, Yeast of

PAGE

. 410
. 420
, 410
. 198

163
161
161
166
162
161
162
161
122
182
184
121
516

V.

Vacuum, Boiling Point of Water in
Vacuum Pans, Express
„ Freitag's
,, ,, Greiner's

,, ,, Grosse's

,, ,, Heating Surface of .

,, ,, Reboux'

., „ Shape of

Short Coil

,, „ Standard

„ ., Vertical Tube

„ Welner-Jelinek
Variation in Cane
Varieties of Cane, Ainakea
„ ,, Aleijada

Altamattie
„ Badilla
„ „ Bamboo ..

,, „ Batavian

„ ,, Belouguet

„ „ Big Ribbon

,, ,, Biltong Berabou

„ „ Blue

,, „ Bois Rouge

Bourbon ..
„ ,, Branchu

,, ,, Bronzeada

„ „ Burke

„ „ Caledonia . .

,, ,, Calvacante

„ CanneMorte
„ „ Cappor

„ „ Cavengerie

,, „ Cayanninha

,, Cayenne
Chalk
Cheribon

. . . . 344

.. 350

. . . . 346

.. 350

.... 348

.. 350

. . . . 346

.. 344

. . . . 340

.. 342

. . . . 344

21

.

. 13,

31

35

21,

23, 25,

31

. .

28

27

28

)()U

30

. .

27

32

13,

23, 24,

25

. . 2,

34

. .

36

27

13, 21,

29

36

.. 34,

39

30

, 13,

21, 28,

31

36

23

30

,, China

„ Chinese

,, Chunnee

,, Cinzehta

,, Creole

„ Crystallina

,, Cuban

,, Danie
Diard

,, Elephant

a ..21,

25, 26, 27,

30,

37

.. .. 23,

25

1

3 . .

.. ..34,

39

i ..

36

35

in a

27, 31,

36

.. 23, 24,

25

Dupon

t

29

27

it . .

2, 13,

32

.21, 24, 25,

27,

Varieties of Cane, Envernizada
„ ., Etam . .

Ferrea .. ..
Ganna
Gogari .. ..
Gon salves
Goru . .
Green . .
Green Rose
Guingham ..
Home
Hope . .
Home
Imperial . .
Irimotu . .
Iscambine ..
Java .. ..
Keni Keni..
Kulloa . . .
Lahaina
La Pice ..
Leeut .. ..
Loethers . .
Louisiana ..
Louzier . .
Maillard . .
Malabar ..
Mamuri
Manila
Manteiga . .
Manulele..
Meerah

Meligeli

Mexican

Mignonne

Mird

Mont Blanc

Moore's

Muntok

Naga B

Nanal

Numa

Oliana

Otaheite .. .. 2,
Oudinot .. .... .

Oura

Palania

Panachee

Papaa

Paunda

Piaverae

Pinang

Po-a-ole .. .. 13,

Portii

Port Mackay . .

Preanger

Purple

Queensland Creole .

Ribbon 26,

Rappoh .. .. 26,

Red

Restali

Rocha

Rose Bamboo

Roxinha

Rurutu

Salangore
Samsara
San Pello
San Salvador

PAGE

.. 36

. .. 27

.. 36

... 34

.. 35

. .. 27

.. 35

.. 27

. .. 33

.. 29

. .. 26

.. 27

... 33

.. 36

... 35

.. 33

... 27

24, 25

32, 34

.. 13
27

.. 25

. .. 25

.. 27
31

.. 29

. .. 29

.. 27

... 34

.. 36

1

28, 33

.. 31

... 27

24, 37

.. 27

... 27

.. 27

. . . 34

.. 27

.2, 34

.. 27

. .. 36

23, 24

... 24

.. 35

. .. 36

.. 27

... 36

.. 34

... 35

.. 30

21, 31

23, 25

31, 38

... 27

.. 27

26, 27
28, 37

27, 28
... 33

.. 34

... 30

.. 27

... 36

.. 35
36
34

ae

27

13, 30,

588

INDEX.

PAGE

, . . . 27
.. 32
27, 37

. ..2,
.. 32,
21, 26,

22,

Varieties of Cane, Seete

Settlers .. ,
,, „ Singapore

,, „ Soerat .. .. ,

„ Tanna .. ..

„ Tip

,, ,, Transparent ..

,, „ Tsimbec

Uba

Ukh .. ..
,, ,, Uouo

Vaihi .. ..
,, ,, Vermehla

Yellow.. ..

Yellow Violet
,t ,, Zwinga

W.

Water, Conservation of, in Soil 98

,, Consumed by Cane 92

„ Evaporation of 20

Flow of, in Pipes 322

Gases Dissolved in 332

Quality of Irrigation 97

,, for Irrigation, Quantity Required. . 91

,, Transpired by Cane 95

Wax of Cane 16

Weeding and Moulding 118

Weeds Associated with Cane 125

Weight, Determination^ Cane.. .. 498, 504

PAGE

Weight, Determination of Juice 499

„ „ Maceration

Water .. 503, 505

,, „ Massecuites .. 497

„ „ Molasses 497

„ „ Press Cake . . 497

„ „ Sugar 504

Weighing Machines, Baldwin's 493

„ „ Blake-Dennison — 497

„ ,, Hedemann's .. .. 493

Howe's 493

Richardson's .. .. 494

Wind on Cane, Effect of 20

Windbreaks 21

Windrowing 117

Wrapping of Cane 123

X.

Xanthine Bases

1*5

Y.

Yeasts Associated with Rum Distilleries. . 515

Budding 515

Fission 515

,, Pure Culture 515

Wild 516

Z.

Zayas System 116

Names.

A.

PAGE

Abady 422

Abel 406

Allan 174, 522, 526

Allihn 459, 468

Anderson 448

Arbuckle 305

Arendrup 28

Arrhenius 256

Ashby 526

Aso 70

Aspinall 286

Asrymusry 535

Atwater 420

B.

Baldwin
Baldwin, D. D.
Barber .. ..

Bates

Beck

.... 24

. . 135

437, 450

. 538

Beeson 259

Benecke 145

Bergmans 184

Berkeley 151

PAGE

Bernadini 70

Besson 251

Bienfait 420

Blake 450

Blake-Dennison 497

Blancke 330

Bligh 23

Bocquin 355

Bodenbender 398

Bojer 129, 141

Bolk 308, 413

Bon&me .. 14, 18, 39, 60, 75, 117, 121, 151, 402

Bonnefin 193

Boot 541

Bort 84

Bouricius 39

Bovell 38, 39

Bowack 425

Bravo 159

Broadbent 38, 473

Broch 433

Browne 15, 16, 169, 260, 393, 455,

456, 463, 468, 520

Bruce 38

Burns 50

Burwcll 411

Butler , 138, 142, 150, 151

589

INDEX.

c.

PAGE

Cameron 88

Campen 120

Carp .. , 509

Carr 473

Carrington 425

Cartier 538

Chantrelle 336

Chapman 175, 290

Chivers 159

Claassen 251, 285, 308, 310, 362

Clark 37

Clerget 457

Cobb .. 8, 132, 138, 139, 140, 143, 152, 153, 155

Cockerell 159

Coffey 533

Collinge 171

Comallonga 240

Cordemoy 1

Cornu 43°

Coupler 530

Cousins.. ..' 27, 526

Crawley 47, 518

Creydt 457

Curin 360

Cuzent 35

D.

Dahl 28

Darwin 156

Davoll 478

De Candolle 88

De la Croix 151, 153

De Meijier 53, 96

De Morn ay 178

De Villa Franca 38

Degener 389

Delbert 172, 175

Delteil 18, 29, 30 45

Deming.. .. .. •• 258

Dessin 308, 311, 312

Diamond 460

Dickoff 140

Druelle-Say 385

Drumm 38

Du Beaufret 46

Duboscq 438

Dubrunfaut 372, 397

Duchaissing 202

Dupont 246, 269, 485

Dutrone 38

Dymond 32

E.

Earle . .
Ebbels
Eckart ..

52, 119

82, 402

19, 23, 39, 47, 61, 64, 70, 76,

98, 99, 100, 122, 261

Edwards 23

Effront 523

Erlich 536

Engler 1

F.

Fauque 402

Faure 193

Fawcett 23

PAGE

Fawcett, Preston & Co 175

Felz 389

Flourens . . 389

Fogarty 177

Fowler .... 114

Francis 207

Frankland 82

Freitag 350

Fric 437

Fries 307

Froggat 137

Fryer 286

Fulton 143

Fulton Iron Works 174

G.

Gallois 246, 269

Gans 251

Gaussiran 159

Gay Lussac 538

Geerligs. .13, 15, 25, 39, 46. 95, 114, 123, 249, 257,
260, 262, 263, 264, 285, 336, 356, 388, 390, 391,

411, 412, 467, 474, 478, 486, 489, 503, 519, 520

Gendar 538

Gerard 388

Glan 429

Godillot 407

Gonsalves 26

Greg 416

Gi-einer 318

Grimbert 456

Grosse 350

Gunning 388, 389, 481

H.

Hackel 1

Hadi 34, 43, 132

Hagemann 291

Hall, A. D 77, 87

Hall, Melmoth " 35, 37

Hall, W. G 176

Hamakers . . . . 240

Harrison.. 23, 24, 25, 28, 30, 31, 33, 38, 39, 49,

69, 70, 71, 95, 124, 153, 157, 444, 452, 519, 526

Hart 39

Hatton 243

Hausbrand 308, 309, 310, 311, 417

Hazewinkel 264, 392, 395, 509

Hedemann 493

Hein 140

Helriegel 83

Henn 150

Hepworth 376

Herles 448

Herzfeld 388, 454

Hildebrand 36

Hilgard 47, 48, 97

Hilton 159

Hlavati 251

Hodek 306

Honig 451

Hoogewerf 420

Hopkins 159

Horne ,33, 37, 450

Horner 106, 107

Horsin-D<§on 308, 335, 432, 501

Howard.. ..138, 143, 150, 151, 152, 153, 154, 340

590

INDEX.

PAGE

Howe 493

Htibner 329

Huch 370

Hudson 257

Hughes 38, 401

Huillard 419

Hulze 388

Hutchinson 71

Hyatt 476

leery

134

J.

Janse 146

Jelinek 285,296,308,335, 406

Jellet 430

Jenman 23, 24, 25, 28, 30, 31, 33, 39

Jesser 452

Jobin 441

Jones, Llewellyn 232

Josse 473

Jungfleisch 456

K.

Kammerling 95, 97

Kessler 236

Kestner 301

Kirkaldy 127

Kjeldalil 481

Knorr 465

Kobus 13, 34, 39, 43

Koebele 127, 130, 133, 136

Konig 304, 420

Kohl 515

Krajewski 175

Kramers 53, 75

Kriiger .. 1, 25, 26, 31, 33, 128, 129, 138, 139, 141

M.

PAGE

Macdonald '. 195

Mackenzie 50

Macglaschan .. ' 516

McNeil 307

Main 473

Manoury 398

Marschall 389

Massee 152

Maxwell .. ..20, 35, 47, 48, 53, 75, 91, 96, 98

Meissl 388, 463

Melsens 248

Meyer 805

Micko T525, 526

Mignon 193

Miller 71, 286, 523

Mitchell 39

Mobisch 488

Mollison 34

Moquette 39

Mukerji 87

Munsen 459, 463

Muntz 82, 388

N.

Naquin 464, 467

Nasini 451

Naudet 238

Newall 292

Nicol 428

Norris 383, 478, 523

Novak . . 336

o.

Oliff 129

Oi-merod 132

O'Shaughnessy 93

O'Sullivan 257, 455

Ostwald.. , 256

Laborde 388

Lamarre 425

Landholt 428

Lagrell 336

Langbein 410

Lange 320

Langen 500

Laurent 432

Lavign ac 24

Le Blanc 178

Leather 34

Lef roy 129

Leinert. 496

Lewton-Brain .. 39, 138, 143, 147, 153, 155,

384, 518, 520

Lillie 299

Ling 467

Link Belt Engineering Co 166

Lippich 431

Littee 39

Liversedge 3

Lobry de Bruyn 264

Loew .. .. 70

Lohraann 509

Louzier 37

Luce .. .159

P.

Parris 38

Patterson 381

Paul 159

Pauly 318

Pavy 467

Peabody 416

Pelaez 193

Peck .. .. 336, 392, 395, 402, 516, 526, 540
Pellet .. ..49, 205, 254, 260, 336, 389,

442, 449, 467, 478, 483, 516, 540

Perichon 238

Perkins 122, 134, 135, 136

Perrault 461

Perromat 39

Perry 304

Peters 435

Pieraerts 457, 469

Pinoff 487

Pitsch 71

Porkong 285

Porter 32

Pott, Cassels & Williamson 377

Pribram 451

Prillieux 151, 153

Purdie 31

591

INDEX.

R.

PAGE
. 142
. 370
. 425
. 251

Rabenhorst

Ragot

Raitt

Ranson

Rebout 350

Renington 425

Rendle 467

Reynoso 46, 116, 117

Richardson 494

Rillieux 287, 289

Risien 202

Robiquet 430

Roche 49

Rohrig 304

Romijns 469

Ronna 95

Rose 509

Roth 3

Rouart 193

Rouf . .. 67

Rousselot 172, 178

Rumphius 38

Russel 202

S.

Sachs 450

Sawyer 36

Scard 55,- 519

Scheibler 398, 400, 449

Schloessing 82

Schmidt & Haensch 436

Schmitz 451

Selwig 320

Sedgwick 51

Seyferth 398

Shorey 16, 47, a36, 516, 519

Sidersky 462

Sikes 541

Silvestri 137

Simance 422

Sloane 159

Smith, Erwiu 144, 156

Smith, Greig 144, 145, 518, 519

Soldaini 467

Soltwedel 23, 32, a3, 34, 38, 146

Soxhlet 461

Spencer, C. N 36

Spencer, G 231, 461, 476, 477

Steffen 398, 399, 400

Stenhouse 75

Stillman ,

, 174, 290

Stohlman . .

410

Stubbs

.. 3, 19, 20, 21, 22, 23,

25, 27, J

J8, 36, 50, 71, 84, 101, 117, 118

Stutzer

481

Subra Rao

117

Sundstrom ..

489

Svorick

320

Swenson

296

PAGE

Tiemann 95

Tourneur 370

Trannin 433

Treub 146

U.

Urech . . 256

V.
Van Deventer 127,129,136

Van Ekenstein

Van Lookeren Campagne

Van't Hoff

Van Trooyen

Veley

Ventzke .

264

75

390

301

519

433

Villele 24, 37

Villavecchia 451

Vivien 482, 485

W.

Wagner 83

Wakker 38, 127, 138, 139. 142

Walker 459, 4*3

Wallace 43

Walton 401

Wanner 424

Ward, Marshall 83

Warrington 82

Watson 130

Watson, Laidlaw & Co 377

Watts 65, 451, 520

Webber 135

Wegelin 329

Wehne 388

Wiechmann 450

Weinberg 169

Welner 296

Went .. 10, 39, 127, 138, 139, 143, 146, 147,

148, 149, 517

373

. 286

Westoii

Wetzel

Wheeler- Wilson .. .. 160

Whitehead 320

Wijnberg 16

Wild 433

Wilfarth 83

Williams 188

Wiley 15, 452, 465, 473

Winogradsky 82

Winter 347, 469, 509

Witcowitz ' 302

Wortmann 457

Wray .. 18, 23, 26, 29, 103, 302

Wulff.. 355

Y.

Yaryan ..
Young..

.. 298
178, 202

T.

Taylor 275 Zamaron

Tayler, Wallis- 163 Zaremba . .

Tempany 451, 520 Zagas

Thiele 424 Zehntner..

Thomson .. 455 Zerban ..

Z.

,.448, 476

.... 296

.. .. 116

133, 136

. 467

592

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642

amounts were found to vary but little. For the moisture determination,
an amount of bagasse equal to 50 or 100 grms. before chopping (i.e.,
48 or 96 grms. respectively if the loss has been 4 per cent, during
chopping) is weighed out on a shallow tray (f in. deep), and heated in
an air-bath for 3 hours at 125° 0. At the end of this time the tray is
weighed quickly, and the moisture calculated from the difference
between the two weighings. For the sugar determination an amount
equal to 100 grms. of the original bagasse (i.e. 96 grms. for a 4 per
cent, loss during chopping) is weighed out into the inner digestion
cup (B), which is 4^ in. high and 4^ in. in diam., of the apparatus,
resembling a "double-cooker," which is illustrated in the figure;
500 c.c. of hot water containing 5 c.c. of a 5 per cent, solution of
sodium carbonate are added, the bagasse pressed down into the liquid
by means of the perforated disc of metal (C) provided with a handle,
and this inner vessel placed in the outer one (A) containing boiling
water. Digestion is continued for an hour, the bagasse being mixed
every 5 minutes by pressing it down with the disc, which is used as a
cover between times. At the end of this time the liquid is allowed
to cool a little, then the weight of bagasse plus solution taken, the

liquid filtered through cheese-cloth,
arid cooled to laboratory temperature ;
99 c.c. are then placed in a 100 c.c.
flask, made up to the 100 c.c. mark
with basic lead acetate solution, filtered
and polarized in a 400 mm. tube. An
alternative method, obviating the use
of the " double- cooker," is to weigh
out the equivalent of 50 grms. into a
quart pot provided with a cover, add
500 c.c. of water containing 2 c.c.
of a 5 per cent, solution of sodium
carbonate, boil gently for an hour,
stirring every 15 minutes, then proceed as just described above. The
polarization of the sample may finally be read from a table given in
this bulletin, or it may be calculated, whichever procedure has been

used, from the following formula : , in which R is the

2X3-8X100

polarimetric reading observed in a 400 mm. tube ; W the weight of
bagasse plus solution corresponding to 100 grms. of bagasse; and f
the fibre content of the bagasse, taken for Hawaiian bagasse as 50.
It is stated that this aqueous digestion method continued for an hour
gives results agreeing well with those obtainable by the alcoholic
extraction method lasting 1^ to 2 hours. Contrary to Priusen
Geerligs' experience with Javan bagasse (this JL, 1909, 156), the
author finds no dextro-rotatory non-sugar body extracted or formed
during the digestion of Hawaiian bagasse.

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