Chapter VII: Part I: Growth, Manufacture and Distribution (2)

From the receiving tanks the syrup is drawn into the pans by a vacuum ranging between twenty-five and twenty-seven inches. The pans are large cast-iron or copper cylinders, standing in a vertical position, with dome-like tops and conical bottoms, almost spherical in shape. Leading from the top is a large pipe through which the vapors from the boiling are drawn off and condensed. On the conical bottom is a large valve, which may be opened when the boiling is finished to allow the _massecuite_ (a French term meaning cooked mass) to drop out.

At regular intervals in the height of the pan there is a series of copper coils, connected with a steam line at one end and a drain line at the other.

The general principle involved in boiling sugar is the separation of the sucrose contained in a solution from the impurities present in that solution, and this is accomplished by evaporation and concentration through the agency of heat. After the sugar is once formed in definite crystals these crystals attract and appropriate the sucrose in solution in the process of building up the crystal structure, while repelling or excluding the impurities, so that, as a consequence, the latter remain in solution. The crystals thus formed are subsequently removed from the solution by means of centrifugal machines. Crystallization, whether in a pure or impure solution, will proceed to only a certain extent, and will only partially remove the sucrose from the solution in one boiling, the limit of crystallization being governed by the amount and nature of impurities present.

The process of boiling is begun by drawing some of the concentrated juice into the pan and turning steam into the coils, which starts the boiling. This is continued until the supersaturation is such that minute crystals of sugar form or “grain out.” By properly timed admissions of fresh concentrated juice, drawn into the pan by vacuum as before, the crystals grow in size and at last the pan becomes filled with a mass of sugar crystals of regular shape and size, immersed in a thick “mother liquor” containing sugar and the impurities that were not removed by the filters or settling tanks.

The size of the grain may be varied at will by the operator in charge, who is known as the sugar boiler. After the grains are once formed, their number (if the sugar boiler is an expert) does not increase, but the size does, as the original grain continually builds up on itself from the outside.

The question may be asked, why is all the moisture not boiled out in the pan and the sugar dropped in a dry, crystallized state? There are several reasons why such a course is impracticable; first, because the impurities, which must be eliminated by crystallization and which are carried off in the mother-liquor, would be boiled into the sugar and make it unsalable; second, because to aid crystallization and prevent scorching or burning on the hot steam coils the mass must be kept in active circulation during the boiling process, or, long before all the moisture could be driven off, a large part of the contents of the pan would be burned on the coils; and third, even if it were practicable to boil the contents down to a solid state, the grains would stick to each other and become one solid mass, which would have to be removed from the pan with bars, picks or chisels. Enough moisture, or rather liquor, is left in the mass to enable it to flow from the pan by gravity. This liquor, with the impurities it carries, is subsequently removed from the sugar by a drying or separating process which will be explained later on.

Massecuite is a viscous, sticky, semi-fluid mass of the consistency of half-formed ice.

The reason sugar “grains” is because the water in the juice has the power to hold in solution only so much sugar. As it goes into the pan, the juice is almost a saturated solution, and as the water is driven off by evaporation, the solids that up to this point have been in solution must of necessity crystallize.

When the sugar boiler decides that the “strike,” that is, the massecuite contained in the pan at one boiling, is satisfactorily grained, he breaks the vacuum by opening a valve on the top of the pan, thus allowing the air to enter. He then opens the valve at the bottom of the pan and the mass drops into a long tank with a rounded bottom, called the mixer, in which a shaft, equipped with paddles, is revolving. The paddles are for the purpose of keeping the mass agitated and in an even condition. The agitation prevents the grains from dropping to the bottom of the tank and forming a solid block, called concrete.

PREPARATION OF CRYSTALS FOR THE MARKET

From the mixer the massecuite runs through spouts into the centrifugal machines. Centrifugal machines are cylindrical-shaped, perforated brass baskets, usually forty inches in diameter and twenty-four inches deep, hung on a central shaft suspended from beams overhead, and surrounded by a solid outside curb or casing.

On the shaft is a pulley, which is driven by a belt connected with an engine or an electric motor. The inside of the basket is lined with a fine-meshed brass screen, which retains the grains of sugar, but allows the liquor to escape freely into the outer casing.

As soon as the centrifugal machine is filled with massecuite from the mixer above, the power is turned on and the machine begins to spin around at an increasing speed until a velocity of one thousand revolutions per minute is reached. The centrifugal action forces practically all the liquor out through the screen and leaves in the machine all the grains of sugar that were formed in the pan. A little dry steam is sometimes turned in to assist in reducing the moisture in the sugar.

The centrifugal is then stopped, a valve in the bottom is opened, and the nearly dry crystallized raw sugar is dropped into bins. From the bins it is drawn off through spouts and packed in sacks containing about one hundred and twenty-five pounds each.

It has been demonstrated that raw sugar containing a large amount of moisture inverts or deteriorates more rapidly than that with a low-moisture content. It is apparent that as moisture adds to the weight, the transportation charges, which are based on tonnage, are greater in the case of wet sugar than in the case of dry. In many of the modern mills, therefore, a further treatment is given the sugar to reduce loss by inversion and lessen freight charges.

From the bins last mentioned the sugar is dropped into revolving drums six feet in diameter and twenty-six feet long, set at an incline so that as the drum revolves the sugar is carried round to the highest point on the circumference of the drum and dropped to the lower side, at the same time traveling from the receiving to the discharging end. The shape, motion and inclined position of the drum cause a perfect shower of sugar in the drum for its entire length and breadth. While it is revolving a current of hot, dry air is drawn through the drum by means of suction fans, and as a result the moisture in the sugar is absorbed by the air and carried out of the building. At this stage the product has a good hard grain of a yellowish-brown color; contains from ninety-six to ninety-seven per cent of pure sugar and about one-half of one per cent of moisture.

From the end of the revolving drum the sugar is drawn off into sacks holding about one hundred and twenty-five pounds each. These sacks are sewed by machinery and put into railroad cars to be hauled to the docks at the shipping port, where the cars are switched under huge hoisting cranes or alongside speedy conveyors which carry the sugar into large seagoing steamers especially built for the trade. Some of these ships have a cargo capacity of two hundred and twenty thousand sacks, and they transport the sugar to the buyers on the mainland in San Francisco, New York or Philadelphia, as the planter directs.

The liquor thrown off by the centrifugals is not lost; it is taken back to the pans and reboiled. After this has been done several times and most of the sugar extracted, the purity is so low and the sugar content so small that it does not pay commercially to reboil further, and the residue is sold as molasses. It contains about thirty-five per cent of sugar and from twelve to fourteen per cent of invert sugar, or glucose, as it is generally called.

Some of the waste molasses is mixed with fodder and tender cane tops and fed to cattle and plantation stock, the sugar content proving of great value as a fattening agent and energy builder. Part of the molasses is sprayed on the bagasse as it leaves the crushers and serves, first, as a fuel under the boilers, and, second, as a fertilizing agent in the form of ashes after it has been burned. During the past few years much of it has been shipped in tank steamers to the mainland, where it is used for the manufacture of spirits and vinegar, and also as the principal ingredient in prepared stock foods which are much in demand today.

Every bag of sugar shipped from the plantation is marked to indicate the plantation from which it came. The net weight of the sugar in each bag is recorded, a sample of the sugar taken and its sucrose content ascertained, for it is on the basis of weight and sucrose content that raw sugar is bought and sold.

From the beginning to the end of the process of manufacture, chemists are vigilantly alert sampling, testing, analyzing and supervising the operations. Records are made of all analyses, temperatures, purities, densities, extractions, etc., and the results tabulated for future reference.

The average cost in Hawaii of preparing the fields, planting, irrigating, fertilizing, cultivating and cutting the cane, manufacturing the sugar and delivering it in the New York market, is about $56.00 per ton of two thousand pounds.

TRANSPORTATION AND DELIVERY OF RAW SUGAR

It has been explained that in Hawaii sugar is packed in one-hundred-and-twenty-five-pound sacks. Methods and customs vary in different countries. For instance, in Cuba it is put up in large gunny bags, each holding an average of three hundred and twenty-five pounds. The same custom prevails in Porto Rico. In Peru, and to a limited extent in Java, sacks containing two hundred and twenty-four pounds are used. A large part of the sugar in Java, however, is put up in bamboo baskets of native make, containing from five hundred to eight hundred pounds. They are about thirty inches in diameter, from thirty-six to forty-eight inches high, and are lined with coarse leaves to prevent the sugar from sifting out between the weavings of the bamboo. Philippine sugar is packed in leaf-lined mats of tough vegetable fiber, each holding about seventy pounds.

These various styles of containers necessitate different methods of handling to and from the ships and by the buyers, but Hawaii will again serve as an example of efficient, modern practice. Outside of what is consumed locally, all Hawaiian sugars are shipped to the mainland of the United States by steamers or sailing vessels to San Francisco, or by steamers to New York or Philadelphia, via the Panama canal.

As sailing vessels are rapidly disappearing from the seas so far as the sugar trade is concerned, reference will be made to steamer traffic only. The steamers are specially built for carrying sugar, having a cargo capacity of from five thousand to thirteen thousand tons, and the best loading and discharging facilities.

When loading in Honolulu, the steamers usually lie alongside wharves covered with immense warehouses, where rapid-speed conveyors carry the sacks of sugar to a point above the ship’s hatches and drop them into chutes which guide them down into the hold of the ship, where they are compactly stowed. On the off-shore side of the vessel small steamers from other island ports lie alongside and hoist the sacks by means of steam winches to a point over the hatch and deposit them in similar chutes. When steamers are loaded from both sides in this manner, as much as three thousand tons, or forty-eight thousand sacks, can be loaded in nine hours.

After a vessel is completely loaded and gets her clearance from the custom house, she departs for San Francisco, twenty-one hundred miles away, or for the Atlantic seaboard, via Panama, as the planter may direct.

The voyage ended, and the quarantine and health regulations complied with, she proceeds to the dock of the buyer, usually a sugar refiner. The Hawaiian planter invariably sells his sugar under contract prior to arrival of the vessel at destination.

Planters in other countries operate differently. Occasionally sugar is sold on the plantation at an agreed price, and the buyer arranges his own transportation. The planter sometimes ships his sugar unsold and negotiates its sale while it is en route. If so sold, it is delivered directly to the buyer on arrival; if not, it must be stored in a warehouse at the planter’s expense pending sale.

The practice of the Hawaiian planter is to sell his sugar to refineries in San Francisco, New York or Philadelphia, under contracts extending over a term of years. It is agreed that the sugar shall be shipped as soon as made and that the refiner will receive it immediately on arrival, the price for each cargo being that quoted in the open New York market for ninety-six-degree centrifugal sugar on the day preceding its arrival.

The value of raw sugar, like that of other staples, is based on supply and demand, and the price fluctuates from day to day according to the requirements of the refiners or the necessities of the sellers.

There are certain rules or trade conditions governing all sales, so that when one man buys and another sells at an agreed price, each knows what he is bargaining for. For instance, raw sugar is bought on the ninety-six-degree centrifugal basis, that is, the price agreed to be paid is for centrifugal sugar containing ninety-six per cent of sucrose. If it contains more sucrose, a higher price is paid; if it contains less, a lower price is paid; all according to an established scale of additions and deductions. Then again, the time of payment for the sugar is well understood. It is usually ten days after the sugar has been finally discharged from the ship, as this allows a sufficient period in which to determine the exact weight of the sugar and the percentage of sucrose it contains. An instrument called a polariscope is invariably employed to determine the amount of sucrose present and the results obtained from its use are absolutely accurate. A description of the operation will undoubtedly prove interesting.

POLARIZATION

The practical working of the polariscope is based upon the property of sucrose to rotate a ray of polarized light to the right.

Ordinary light is the effect on the eye of vibrations of the ether. These vibrations occur in all directions, but by certain optical devices they may be confined to a single plane, and light thus confined is called polarized. If rays of polarized light pass through a layer of certain bodies, _e. g._, quartz, sugar and many others, the plane in which the vibrations occur is rotated, and the polariscope has been devised for the purpose of measuring the rotation of the plane of polarization.

Polarized light, as used in the polariscope, is obtained from the Nicol prism or some development of it. Ordinary light passing through crystals of certain bodies, of which Iceland spar is an example, is split into two rays, one of which is known as the ordinary and the other as the extraordinary ray. A Nicol prism is made of two wedge-shaped pieces of Iceland spar, cemented together with a film of Canada balsam.

The accompanying sketch gives a good idea of the arrangement of an ordinary polariscope.

A strong white light, _e_, enters the instrument through a lens at _f_, to the Nicol prism _b_, by which it is polarized. The ordinary ray is dispersed, while the extraordinary or polarized ray passes straight through and enters the sugar solution contained in the tube _c_, which has glass ends. In passing through this solution it is given a rotary motion to the right or to the left, according as the sugar in the solution is sucrose or levulose. When it emerges from the tube containing the sugar solution, the now rotated polarized ray encounters a second Nicol prism, of which one of the wedges is fixed and the other movable. This prism is called the analyzer. A pointer, controlled by a thumb screw, is attached to it, and when the correction of the polarized ray’s rotation has been made with precision by adjustment of the wedges, the pointer will indicate directly and accurately on a scale the amount of sucrose in the solution under test, because the polarized ray was rotated in exact proportion to the amount of sucrose contained in the solution through which it passed.

The polariscope is made and set so that a standard weight of pure sugar (C₁₂H₂₂O₁₁), dissolved in a standard quantity of pure water, and placed in a tube of given length, will rotate the ray of polarized light in passing through, to a point on the scale marked one hundred degrees, the equivalent of per cent. Also, that by using the same quantity of water, but twenty-five per cent, fifty per cent, or seventy-five per cent less weight of sugar, the rotation will show seventy-five degrees, fifty degrees or twenty-five degrees of pure sugar, as the case may be.

A sample is drawn from each bag of sugar and all of these go to make up a general average sample. The standard quantity is carefully weighed, dissolved with the standard amount of water, clarified, filtered and poured into a tube with glass ends, which is then inserted in the polariscope between the eye of the operator and a strong artificial light. When the operator making the test applies his eye to the instrument, he sees a distinct shadow on a lens in the line of vision, one side being light and the other dark. He then turns the thumb screw which adjusts the analyzer until the whole field of vision is neutral, which indicates that the rotation of the polarized ray has been corrected. The pointer on the scale now shows the exact percentage of sucrose present in the raw sugar, ninety-four, ninety-five, ninety-six degrees, or whatever it may be. This test determines the real value of the sugar, based on the market quotation for ninety-six-degree sugar. If the polarization should show exactly ninety-six degrees, the price to be paid for the sugar and the market quotation will be identical.

In most sugar-producing countries the government imposes an import tax on all foreign sugars, in order to obtain revenue to defray governmental expenses and to protect the domestic industry, if any, against competition with other countries in which cost of materials and labor may be lower. Commodities produced in a country naturally add to its development and wealth, and this explains the fostering of the sugar industry by various governments.

The United States duty on foreign sugar is at present $1.256 per one hundred pounds of ninety-six-degree raw sugar. On account of our treaties with Cuba, the Cuban planter is allowed a deduction of twenty per cent, and, therefore, pays a duty of $1.0048 per hundred pounds, which, owing to trade conditions, is the duty effective today in the United States.

Sugars produced in the insular possessions, Porto Rico and the Philippine islands, are admitted free of duty.

In 1898, the Hawaiian islands, through annexation, became a part of the United States, consequently no duty is assessed on sugar or any other Hawaiian product.

Every vessel coming into a port of the United States must be entered at the custom house, where a record is kept of the port whence she came and of what her cargo consists. If from a domestic port, she is permitted to discharge her cargo without delay; if from a foreign one, customs officials are immediately sent on board to watch the cargo as it is discharged and supervise the tallying, checking or weighing, according to the class of merchandise. Besides being weighed, sugar is carefully sampled and the percentage of sucrose ascertained by the polariscope, for the customs duty is based upon the purity of the sugar, all raws testing not above seventy-five degrees polarization paying .71 cent per pound and .026 cent per pound for each additional degree. This is equivalent to 1.256 cents per pound for ninety-six-degree sugar.

The people of the United States used 4,257,714 short tons of sugar in the year 1915. It was nearly all produced within the United States or in countries enjoying tariff concessions, as follows:

SHORT TONS
Hawaiian islands (Cane) 570,375, U. S. territory.
Louisiana (Cane) 251,740, U. S. territory.
Domestic production (Beet) 861,568, U. S. territory.
” ” (Maple) 17,248, U. S. territory.
Porto Rico (Cane) 336,347, insular possession.
Philippine islands (Cane) 134,626, insular possession.
Cuba (Cane) 2,062,594, reciprocity treaty.
Foreign sugar (Cane) 23,216, full duty-paying.
----------
4,257,714

Aside from the small amount of full-duty-paying foreign sugar imported, the only sugar in the above list that paid duty came from Cuba. It is evident, therefore, that under ordinary conditions an increase in the crops of any of the places mentioned would result in a surplus of sugar in the American market. In 1916, with the beet production of Continental Europe locked up by the war, Cuba’s increased output has been absorbed by Great Britain, France, Italy and Greece.

Steamers from Hawaiian ports, after arriving and entering at the custom house and passing quarantine and health officers, proceed immediately to refinery docks to discharge cargo.

REFINING OF RAW SUGAR

Cane-sugar refineries are always located in great seaport towns for the reason that, as practically all cane sugar is grown in the tropics, it must be transported by water to the world’s markets.

The refining operation is by no means as simple as may at first appear. It is essential that the finished product be almost chemically pure (99.8 per cent), and the greatest care must be exercised to obtain a perfectly white color, as well as a hard, lustrous grain.

The question naturally arises, why do not the planters of Hawaii, Cuba, Java and other raw-sugar-producing countries carry their process a few steps further and make a pure white sugar as the refiners do? This has been attempted many times, but has almost always been found impracticable, notwithstanding the fact that there is no mechanical or chemical reason why.

Among the arguments in favor of a mainland seaport site, the following may be mentioned:

1. The producing centers are generally far distant from consuming markets. Refineries located in the tropics would be under unusual expense for transporting and selling the refined article.

2. A refinery in the tropics would be out of direct and prompt touch with the individual requirements of the buyers.

3. Refined sugar should be moved and sold as soon as possible after its manufacture, so there follows the necessity for adequate dock and rail facilities as means of quick communication with the market.

4. An abundant supply of pure, soft water for refining purposes, and salt or fresh water for condensing, as well as fuel for the generating of steam, must be readily available. Another most important requisite is skilled labor, which is more easily obtained in populous seaport cities than in the small, isolated towns of the tropics.

5. There are many commodities used in the refining of sugar and in packing it for shipment that can be purchased more advantageously, both as regards price and promptness of delivery, in the great commercial ports than in the sugar-growing districts. Among these are bone-char, lime, acids, cotton filter-bags, burlap, cotton cloth, boxes, barrels, cartons, iron, steel and machinery of all kinds.

6. A sugar refinery is operated the entire twelve months of the year, while a raw-sugar mill must of necessity take care of the crop of cane in about eight months. To refine sugar where it is grown would require refining machinery capable of handling the entire output in the eight-month period, and during the remaining four months the plant would remain idle. This would mean a larger investment proportionately than that made in a refinery in a consuming center, running steadily the year round.

7. Refined sugar very rapidly absorbs moisture, and while in transit from the tropic to the temperate zone it is very apt to become lumpy or caked, which would involve reprocessing at great expense at the point of consumption. The unavoidable damage to the packages in loading and discharging results in heavy expense, as all packages must be delivered to the buyer in first-class condition. To avoid hardening, refined sugar should never be piled very high, and it is an unsolved problem whether refined sugar will stand long ocean transportation in cargo lots without caking and damage by breaking of the inside cotton sacks. If shipped in barrels, the freight rate is proportionately higher.

8. Larger capital would also be required, as refined sugar must be carried on hand and must await the consumer’s demand, while raw sugar generally has a prompt and ready market and can be quickly converted into cash.

With these difficulties presenting themselves to a prospective sugar refiner in a raw-sugar-producing country, the shipping of raw sugar to refineries at great distances does not seem at all unreasonable.

Raw sugars show considerable variance in their component parts, and so it follows that some are less easily refined than others. Such differences are generally due to diverse methods of culture, amount of fertilizer used, the processes of manufacture and the efficiency of extraction. If the extraction be high, a large percentage of the salts in the cane is taken up, and these salts prevent or retard the complete crystallization of the pure sugar in refining. One part of ash prevents several times its own weight of sugar from crystallizing, hence it is readily seen that raw sugars with a low ash content are preferred by refiners.

Sugar refining is the production of pure white sugar in granular form, after the removal of the impurities from the raw product. Nine operations are necessary to bring about this result:

1. _Washing_:

Removal of superfluous impurities.

2. _Melting_:

Changing the solid raw sugar into liquid form by melting with
water.

3. _Defecation_:

Precipitation of suspended and insoluble impurities.

4. _Bag and Bone-char Filtration_:

Removal of suspended impurities, color and soluble impurities.

5. _Crystallization_:

Production of crystals by concentration.

6. _Partial Drying_:

Purging crystals from syrup in centrifugals.

7. _Final Drying_:

The driving off of all remaining moisture.

8. _Sorting of Crystals_:

Sorting of grains according to size to meet market demands.

9. _Packing_:

Putting in various forms of containers.

A refinery consists of a group of buildings, each of which has been constructed for a special purpose and for convenience and economy in operation. They are as follows:

1. The melt or wash house.
2. The char house.
3. The pan house.
4. The packing house.
5. The boiler house.
6. The pump and power house.

In addition there are offices, shops, laboratories, and last, but by no means least, very extensive warehouses.

To begin at the beginning it will be necessary to start with the steamer laden with raw sugar and made fast to the wharf in front of the warehouse that forms part of the refining plant.

The sugar is hoisted out of the ships in sling-loads by powerful winches, and landed on a platform on the dock alongside the ship. Each sling-load consists of from twelve to twenty sacks, or the equivalent weight in baskets or mats, as the case may be. As soon as the sacks are landed, they are sorted according to mark, put on trucks to be run over a scale set in the floor, and their gross weight recorded.

As the truck leaves the scale, the samplers take a sample from each sack. This is done with a tryer, a long, hollow steel tube, open on one side and sharp at one end, with a handle on the other for the sampler to grasp when forcing the tryer into the sack. The individual sample from each sack of each different mark is deposited in large closed cans until the cargo is completely discharged, when an average sample of all the individual samples of each mark is made up and used in the laboratory to determine the polarization or sucrose content of the various lots comprising the entire cargo. The value of the sugar is fixed by this polarization.

The weights of the various truck-loads of sugar passing over the scales are totaled and the weight of the sacks, baskets or mats deducted, giving the net weight of the sugar.

Hawaiian sacks weigh exactly one pound; Cuban, Javan and Peruvian sacks about three and one-half pounds. Javan baskets weigh from twelve to fifteen pounds, and Philippine mats about four pounds.

In order to facilitate the weighing and simplify the calculations, in cases where the exact weight of the sacks is known, every truck is made to weigh the same by ascertaining the weight of the heaviest and then putting small iron nuts or washers on the rods of the other trucks until each of them exactly counterbalances the heaviest. One truck is then placed on the scale and the scale is brought to a perfect balance, just as though there were no truck on it. In this way the weight of the truck is never recorded, which greatly simplifies the entire weighing operation.

One crew of men will discharge from 1300 to 1500 sacks of sugar per hour from each hatch of a steamer, or a minimum of 731 tons per day of nine hours. As three hatches are usually worked at the same time, it will be seen that from 2200 to 2500 short tons are taken out every day.

From the scales the sugar is deposited on a depressed conveyor in the floor and carried directly into the melt house of the refinery, except the sugar that must of necessity be stored in the warehouse for future use, in which case it is dumped from the trucks on piling machines that elevate it to any height desired, and it is arranged neatly and compactly by the piling crew.

The wharves and docks of a sugar refinery are, as a rule, scenes of unusual activity and interest. Besides the large number of men engaged in hoisting, trucking, weighing, sampling and piling the sugar, there are the sailors, whose calling always possesses a certain fascination for the landsman. A motley crew they are, bronzed by wind and sun, gathered from all countries and climes. There is the simple, kindly native of Hawaii, gentle-eyed, soft of speech and born with a love for the sea; he prides himself upon his skill in swimming and diving, and when the day’s work is done, entertains his shipmates by singing the plaintive melodies of his native land, accompanying himself on the ukulele, the stringed instrument of the South Seas. Should there be a number of his fellow islanders among the crew, the evening’s program is almost certain to be varied by the native hula hula dance, which generally brings marked applause from the onlookers. Presiding over the galley, or ship’s kitchen, is the almond-eyed Chinaman, now shorn of his queue; an excellent cook who loves to gamble after his pots and pans are washed and put away in place; a shrewd gamester, but scrupulously honest. Beside him stands a fierce-looking Malay, sullen, morose and taciturn, whose sharp, white teeth carry a sinister suggestion of the good old days of cannibalism. His neighbor is a Filipino, short in stature, keen-eyed and alert, while in the background are one or two individuals who from their appearance might be direct descendants of the buccaneers who ravaged the Spanish Main in Sir Henry Morgan’s time.

The average sailor is fond of pets, and here there is no lack of them, parrots and monkeys for the most part, and the sayings of the former clearly indicate a total absence of Sunday-school training.

Sugar ships bring rare fruits and vegetables from the tropics, and the employés of the refinery have plenty of opportunities to enjoy such luxuries as fresh pineapples, bananas, guavas, papaias, alligator pears, breadfruit and mangoes.

A visit to the docks of a sugar refinery during the time vessels from foreign ports are lying there is well worth while, although in these days of steam, the picturesque features are not so pronounced as they were before the passing of the sailing vessel.

WASHING

REMOVAL OF SUPERFICIAL IMPURITIES

As a starting point in the refining process the melt house will be first considered. It is so called because it is there that the raw sugar enters the refining process by being melted or dissolved in water.

The conveyor, upon which the bags were deposited in the warehouse, delivers them on a platform on the top floor of the building. As they come to this platform from the conveyor, workmen with keen-edged knives seize them and, with a deft, swift slash, cut the twine sewing at the top of the bag without injuring the burlap fabric. The bag is then pulled off the platform, mouth downward, so that the sugar falls out and passes through an iron grating into a large bin beneath. If the sugar should happen to be caked or lumpy, it is sent through crushers and broken up.

As a certain amount of sugar adheres to the inside of the bags, they are washed in large revolving machines and in this operation the sugar dissolves in the water (called sweet water), from which it is extracted later. They are then partially dried in centrifugal machines and hung on hooks on a traveling chain conveyor that passes through the upper part of the boiler house, where the waste heat thoroughly dries them. In returning, the conveyor passes through the bag room and, by means of an automatic device, the bags are dropped alongside the printing presses. Here the name of the refinery, the kind of sugar and the net weight they are to contain are printed upon them. These burlap bags are then lined with a white cotton bag, after which they are made into bundles and sent to the packing room to be filled with sugar. It will be seen, therefore, that the bags from Hawaii in which the raw sugar is received are put to good use. This, however, does not apply to those that come from Cuba or Java; they are too large to serve as containers for the refined product, and after being washed and dried are sold for what they will bring.

The white cotton bags are made at the refinery, and a plant turning out one thousand tons of sugar each twenty-four hours will use twenty-five thousand yards of cotton sheeting per day if all the output is packed in one-hundred-pound bags.

The bin into which the raw sugar is dumped holds enough sugar to keep the refinery supplied during the twenty-four hours run, but the entire quantity is “cut in” during the day. The advantages of this arrangement are that it avoids any delay in operation due to mechanical troubles with conveyors and because more efficient work is accomplished during the daylight hours. The employés prefer to work on the day shift and, wherever possible, night work is avoided.

From the bottom of the bin the sugar falls into a mixing machine, called the mingler. This is an oblong tank with a semi-cylindrical bottom, near which is a revolving horizontal shaft, with arms or paddles attached which thoroughly stir and mix the sugar with syrup that is added at this point. The reason for using syrup instead of water is that the former, being a saturated sugar solution, does not melt the sugar as water would.

The resultant mixture, called magma, looks a good deal like a soft, brown mortar. It is, in fact, raw-sugar crystals swimming in syrup. This consistency is needed to allow the magma to work freely in the centrifugals, the next operation. Most of the impurities contained in raw sugar are superficial, that is, adhering to the outside of the grain. They may be more or less readily removed by washing the surfaces of the crystals with water.

From the mingler the magma drops to the floor below into centrifugal machines running at the rate of 1100 revolutions per minute. A “charge” consists of about nine hundred pounds of magma. As the machine fills, the centrifugal force causes the magma to rise in a vertical wall around the inside circumference of the basket, at the same time throwing off the syrup that was added on the floor above, and leaving in the machine about five hundred pounds of the raw sugar as it came from the plantation. Water is then sprayed into the machine under high pressure, through a nozzle which divides it into very fine particles and throws it against the wall of sugar in the machine. The water, passing through the sugar by the centrifugal force, washes each face of each crystal and carries off the impurities, together with a certain amount of sugar. The quantity of water used per machine in each filling is from one to two and a half gallons, depending upon the quality of the sugar.

This water, now a syrup, with the impurities and sugar it contains, is drawn from the machine, part of it being pumped to the floor above to mix with new raw sugar coming in. The remainder is treated, filtered, boiled and made into raw sugar, which, in turn, goes direct to the melt or through the washing process again. The result of this washing is that the purity of Hawaiian raw sugar is raised from about 97.2 to 99.2 per cent, and there now remains but 0.8 per cent of impurities to be removed.

The washed sugar is dropped from the centrifugal basket through a large opening in the bottom of the machine with the aid of a mechanical device called a discharger, which greatly reduces the manual labor.

Until very recently the sugar was discharged from the centrifugals by hand, the men digging it out with wooden paddles in a difficult, laborious way. One day, a few years ago, a clear-brained, observant American lad working in a beet-sugar factory, conceived the idea that a centrifugal could be emptied by mechanical means. He worked long and assiduously upon the problem, and after much experimenting and many trials and disappointments was granted a patent by the United States government. Full of hope and confidence, he had several machines constructed and took them to a sugar refiner, sure of being favorably received. He met with rebuff and ridicule. The refinery engineer was too busy with other matters to examine or give any attention to the appliance. The next man to whom he presented it was even more indifferent than the first; he coldly informed the patentee that he had been in the sugar business for thirty years, that no such machine would work, and that the only way to take sugar out of a centrifugal was by hand.

After months of effort and repeated failures, he induced the superintendent of a beet-sugar factory to allow him to install and test the device at his own expense. It was thrown out after a few days’ trial, and the inventor became well-nigh desperate, although still positive as to the merits of his discharger.

Finally he succeeded in gaining the ear of the manager of a large refinery, who, after listening attentively to his earnest argument, at length became convinced by it. As a result of the interview, it was arranged between them that the machines rejected by the beet-sugar factory should be installed in the refinery and operated for a period of thirty days, under the direct supervision of the inventor. The test was successful in every particular and conclusively proved the efficiency of the discharger.

The refiner was gratified because on account of the saving in time the capacity of the centrifugals was materially increased; the men operating the centrifugals were hugely pleased, as the arduous work of emptying by hand was entirely eliminated, and the inventor was happy, for he had vindicated himself.

An order for a large number of the machines was placed at once and every centrifugal in the refinery was equipped with one. Today they are installed in nearly every refinery and factory in the United States, and in many raw-sugar plantation mills as well.

MELTING

CHANGING THE SOLID RAW SUGAR INTO LIQUID FORM

From the centrifugals the washed sugar drops to the melter pan on the floor below. This is a cylindrical tank in the center of which is a revolving vertical shaft, to which are attached horizontal paddles that serve to facilitate the dissolving of the sugar with the hot water that is now added. Only enough water is added to bring the resultant liquor to a density of 58.6 per cent of solid matter.

The raw sugar having been washed and, to use a technical term, _melted_, leaves the melt house at this point.

DEFECATION

PRECIPITATION OF SUSPENDED AND INSOLUBLE IMPURITIES

From the “melt” the liquor is pumped to the top floor of the char house, which is usually a structure of from twelve to fourteen stories high. The reason for building to such a height is the advantage gained by utilizing the force of gravity and by this means handling the liquors and bone-char from floor to floor without mechanical aid.

The liquor is delivered into a number of cylindrical tanks equipped with a coil of pipe through which steam is passed for heating the liquor, each tank being capable of holding 25,000 pounds of liquor. Around the bottoms of the tanks are perforated pipes through which compressed air is forced to agitate and thoroughly mix the solution. On account of this air being blown in, these tanks are called blow-ups. By means of the steam coil the temperature of the liquor is kept at 190 degrees, which makes it less viscous than cold liquor, thus facilitating subsequent filtration and hastening the reaction of the lime and acid added at this point.

As the liquor comes into the blow-ups it varies in color from a straw yellow to a dark brown, and contains a considerable amount of suspended and insoluble impurities which must be removed. Some of these impurities are present in the raw sugar, and others, such as pieces of twine, lint from the bags, fine particles of leaves from the Java baskets and Philippine mats, are traceable to the opening of the containers in the melt house.

The process of removal is called defecation. In former years this was accomplished by adding bullocks’ blood to the raw-sugar liquor in the blow-ups and heating the mixture until the scum which rose to the surface cracked, when the solution below was found perfectly clear, or, in the language of the refinery man, _bright_. Today, however, chemicals are the defecating agents, those most commonly used being phosphoric acid and lime. Phosphoric acid, neutralized with lime, throws down a heavy, flocculent precipitate which, as it settles, sweeps the solution and drags down all the suspended matter, gums, etc., leaving the liquor above clear and transparent.

The precipitate must now be removed, and this is accomplished by running the liquor through the bag filters on the floor below. These filters are tight iron boxes, about sixteen feet long, six feet wide and seven feet high. The top of the box is depressed about eight inches below the sides and ends, thus forming a tank. This top is perforated with five hundred holes, one and one-half inches in diameter. From the bottom of the iron box is an outlet pipe leading into tanks below.

In each of the holes on the inside top of the box is screwed a so-called “brass bottle,” conical in shape, to which is securely attached a closely-woven cotton filter bag, about twenty-four inches wide and seventy inches long. This filter bag is encased in a heavier and stronger cotton sheath, or sleeve, about eight inches wide, which adds strength and keeps the twenty-four-inch bag in folds so as to give an effect similar to that of a folded paper filter, frequently seen in drug stores. Each bag filter contains five hundred of these bags, suspended vertically from the top.

Before any liquor is run on the filters, the bags and the iron box are heated by means of steam to bring the apparatus to a temperature of about 190 degrees Fahrenheit. This prevents the chilling of the sugar liquor by cold bags, which would cause the bags to become “blocked,” as it is technically called. The liquor from the blow-ups, at 190 degrees temperature, is now turned into the depressed tank on the top of the filter and flows through the perforations into the bags attached on the inside, down through the bags, and finds an exit through the bottom of the filter into the tanks below.

As the first liquor comes through the bags, it is a little cloudy, but in a few minutes, as the pores of the bags fill with the insoluble substances, it becomes perfectly bright, all the suspended and insoluble impurities remaining in the bags, together with the precipitates drawn over from the blow-ups. The cloudy liquor is pumped to the top of the filter and clarified by being run through a second time. It is interesting to know that it is not really the bag that does the filtering, but the thin layer of sediment that is deposited from the liquor itself on the inner surface of the bag. The cotton bags are made in a particular manner, and from a fabric especially adapted to catch the sediment and to form, in conjunction with it, an excellent filtering medium.

The liquor, as it runs into the tanks, must be carefully watched, for sometimes a bag inside the filter breaks, which causes cloudy liquor by allowing the precipitates to gain entrance into the clear liquor. As soon as this is noticed, samples are taken from the outlet of each filter and the defective one found and investigated.

When a bag is torn, or develops a hole, the liquor runs through the opening on the top of the filter so fast that it forms a little whirlpool, which shows the bag that is broken. A wooden plug is immediately driven into the opening and that particular bag cut out. The men on the bag filters soon become so expert that they detect broken bags and plug them before the cloudy liquor gets to the inspection station. It is essential that the liquor be freed from all suspended impurities at this station before the next step is taken, hence great care and watchfulness must be exercised.

In time the coating of sediment, gums and precipitates on the inside of the bag becomes so thick that the liquor runs very slowly and finally stops. The refinery term for this condition is “stuck-up.” Depending on the impurities in the original liquor, the bag filters will continue to filter the liquor for from twelve to twenty hours and sometimes longer.

After the bags are “stuck-up,” the liquor remaining in them is sucked out by means of vacuum through a small pipe attached to a long rubber hose and inserted in the bags through the holes in the top of the filter. The liquor thus sucked out of the “stuck-up” bags is sent to the blow-ups and reprocessed with new liquor, thus beginning its journey anew.

As soon as the liquor is sucked out, hot water is run through to reduce the sugar contents of the filter. This water is saved and the sugar it takes up is subsequently recovered. The filter is then opened by means of an electric hoist traveling on an overhead track immediately above the filters. Chains are attached to the top of the filter and the hoist elevates top, bags and all, to a point sufficiently high for the bags attached to the top to clear the adjoining filters. The top and bags are then moved along the track to the washing station. Meanwhile another hoist has delivered a duplicate top, with fresh bags attached, to the filter, where it is lowered into place. In this way the filter is again in operation within five minutes. At the washing station the bags just taken from the filter are detached from the top for washing, and the top is sent to a point where clean bags are again attached. It is then ready to go into another filter.

At the washing station the dirty bags are pulled out of the sheaths and turned inside out in tanks containing water, thus releasing a large quantity of the impurities. The bags and sheaths are then thrown into washing machines, where all the remaining impurities and sugar are washed out of them. From the washers the bags are put into centrifugal machines, or through powerful wringers, and dried sufficiently to permit being rehandled. They are then resheathed and made ready to be attached to another top.

The water from the washers contains a large amount of sugar and is conducted to a tank similar to one of the blow-ups, where it is treated with lime and diluted with water at 190 degrees Fahrenheit until it contains only from ten to twelve per cent of solid matter. This liquid is then pumped through filter presses and the impurities removed. The “sweet water,” as it is termed, which now contains practically all the sugar, is collected in tanks and the sugar is ultimately extracted by evaporation, filtration and boiling to grain.

The impurities removed by the filter presses consist of sand, portions of bags and baskets, phosphates, hair, lime, salts and gums, in fact every kind of foreign matter that finds its way into raw sugar either in the process of manufacture or in transportation. A small amount of sugar accompanies this refuse, but as its recovery would cost more than it is worth, it is allowed to run to waste. The filter-press cake, as it is called, contains valuable fertilizing agents, and when conditions permit it is used for fertilizing purposes, otherwise it is run to waste.

BONE-CHAR FILTRATION

REMOVAL OF COLOR

To resume the course of the bag-filtered liquor, from which the superficial, the suspended and insoluble impurities have been removed and which is now the color of clear amber, the next step is bone-char filtration.

Bone-char, bone-coal or bone-black, as it is variously called, is made from the bones of animals. After the fat and glue are removed, the bones are subjected to a dry distillation which carbonizes them. These charred bones are then broken into very small pieces, or until they will pass through a ten-mesh screen and remain on a thirty-mesh screen; in other words, the size of the grains used in a sugar refinery vary from one-tenth to one-thirtieth of an inch. If properly manufactured, the grains are hard, porous, and have a great affinity for moisture.

Bone-char has the peculiar property of removing from the sugar liquor, in some unknown mechanical way, not only the soluble salts but the coloring matter as well. The elimination of the salts and coloring matter facilitates the subsequent crystallization.

The char house is, therefore, by far the most important station in a refinery, for failure in the char house means failure throughout.

Contrary to the general practice in Europe, beet-sugar factories in the United States do not use bone-char, and consequently do not take all the coloring matter and salts out of the liquor. They secure a white sugar by other methods, which will be explained later on. In a cane-sugar refinery, however, the coloring matter and impurities are entirely eliminated, and the product is invariably pure and white.

The char filters are cast-iron cylinders, usually ten feet in diameter and twenty feet high, with doors at the top for entrance of the char and openings at the bottom through which it is removed. There are also many pipe connections for the introduction and outlet of liquors, steam, hot water and compressed air. The filters are insulated on the outside with asbestos or some other non-conductor of heat to prevent the temperature of the liquor from being lowered as it passes through. Each filter has a capacity of from sixty thousand to eighty thousand pounds of bone-char.

At the bottom of the filter is a perforated iron plate. Over this is placed a coarsely woven cotton blanket, through which the liquor will pass, but which prevents the char from escaping from the filter with the liquor or wash water. After the blanket is set in place, the char is delivered by gravity through an overhead pipe into the filter, until it is entirely full. The char, as it goes in, has a temperature of from 170 to 180 degrees Fahrenheit, and the bag-filtered liquor which is then run on has a slightly higher temperature.