No. VII. TECHNOLOGY.—PART IV. THE PERIER-POSSOZ METHOD OP DEFECATION AND CARBON- I ATATION. Some manufacturers of beet root sugar in Europe have adopted the new process of Perier-Possoz, which we shall here describe as concisely as we can possibly do it, consistently with clearness. The milk of lime used has to be divided very finely, by being passed through a close-woven metallic sieve. It must contain 2 par cent of lime, and will then indicate 10 on Baumes areometer. I Twenty five parts by measure (or a little more), of this solu- tion are to be added to every 1,000 parts, by measure, of juice to j be operated on, but gradually, or in eight or ten successive; additions, during which the temperature of the juice is j raised from 138 to 158 Fah. j At first a greenish albuminous scum is coagulated, but at a later period colorless substances are precipitated. The limed juice is now submitted to the action of carbonic acid gas while it is being stirred, and while at the same time a small stream of milk of lime is allowed to continuously flow into it. This lime, as it is introduced into the juice, is j rapidly dissolved in it, and precipitated, carrying along most of the coloring matters and impurities contained in the I liquid. I The quantity of lime thus gradually added to the juice, varies from 2 to 8 parts in 1,000 for beets of good quality, and from 10 to 15 for beets of inferior quality. The carbonatation is arrested at a moment when the juice contains only from 1 to 2 parts in 1,000 of unprecipitated lime. ] This is known by the rapid clearing of a trial sample, or, i better, by mixing a small quantity of the juice to be tested with an equal volume of a solution of chloride of iron of a specific gravity of 10035, and of a temperature of 59 Fah., which solution will indicate about 1 on Baumes areometer, j If now a few drops of this mixture be dropped into a solution of ferro-cyanide of potassa, and no blue color be produced, it is a sign that the carbonatation must be further continued. If, on the contrary, a blue color is developed in the cyanide solution, then the first part of the operation is known to have been concluded satisfactorily. j The juice, after this point has been reached, is made to flow I into decantators, where it is allowed to rest and settle for the space of from 15 to 20 minutes. From these it is run into a second set of defecating pans, where a new addition of lime is made, amounting to one part in one thousand of juice. This is half the quantity used during the first part of this mode of manufacture. Carbonic acid is again immediately admitted, and allowed to flow until complete saturation is effected, which is known by the same trial as above, with this simple difference, that the chloride of iron test solution must have been diluted with seven times its volume of water. As soon as the right degree of saturation has been attained, the juice is heated to the boiling point in order to drive out the excess of carbonic acid. The carbonatated juice is now run into a second set of decantators, where it is allowed to clear itself when it is ready to be conveyed to the bone-black filters for further treatment. This process furnishes a larger amount of scums and of deposits than are obtained by the ordinary method, described by us in a previous article, and consequently the juice is of a better quality; but it is very doubtful, in our mind, whether in this country the extra expense for lime for the production of carbonic acid, for the lost time, and for the increased labor, will be compensated for by the saving in bone black effected by this Perrier-Possoz system of double defecation and of double carbonatation. THE JELINEK PROCESS. By this new process, defecation and carbonatation are simultaneous, and terminated in a single operation, instead of in j two successive ones, as in the previous method. The pans used are furnished with a carbonic acid coil pipe, and are deeper than the ordinary defecating pans. The juice i admitted into them is comparatively cold, and must never exceed in temperature 140 Fah. At least two per cent in weight of lime is added to the j nice in the shape of milk of lime, and carbonic acid gas being J admitted, the heat is gradually increased until precipitates rapidly form, and fall to the bottom. This process is based on the theory of acting on coldjuice at first so as to produce a solution of saccharate of sugar, out of which the carbonic acid gas precipitates the lime as carbonate of lime, which carries along with it a certain amount of organic matter, freeing, at the same time, the sugar which recombines with a portion of lime, to be again freed by a second decomposition of the saccharate and consequent precipitation of carbonate of lime, and so on an indefinite number of times during the period of the one single operation. The carbonic acid is admitted in the pans when the temperature of the juice has reached from 133 to 144 Fah.; at first in small quantities only, but it is gradually increased in quantity in such a manner that the full extent of its production is utilized by the time the temperature of the juice has attained 175 Fah. In many manufactories where Jelineks method has been adopted, it has been modified in various ways, both as regards the quantity of lime used, the manner of introducing it into the juice (in one or more successive additions), as also in respect to the mode of admitting the carbonic acid gas, and as to the temperature at which the saturation is effected. We cannot possibly enter here into the detailed account of these various modifications of the original Frey and Jelinek pro. ;esa, which demands a much larger amount of lime and of carbonic acid gas, and produces a much larger quantity of seuini md of deposits than the common mode of proceeding. It is, iowever, more simple, and appears to be as effective as the Perrier-Possoz process we have described above. THE CHEMISTRY OP BEET ROOT STJGAE, JUICE, AND MOLASSES. The manager of a beet root sugar factory must be acquainted with at least the rudiments of the science of chemistry, without which he cannot possibly understand the why and wherefore of the operations he is directing, and, consequently, nust be also ignorant of the means placed at his disposal for Dvercoming many of the practical difficulties he is sure to sncotinter during the course of a sugar campaign. For this reason we have thought that a few words on this very important subject would not be misplaced at this point of our purely practical technological exhibition of the art of extracting sugar from beets, as it may serve to render more compre-tiensible to others what we have heretofore written, and what further remains for us to say. The sugar extracted from the beet is perfectly identical with; ane sugar in every respect; its specific gravity being 1-623, svater being represented by 1. Its chemical composition is : Carbon, 72 parts; hydrogen, Uparts, and oxygen 88 parts by weight. Sugar forms with lime, two compounds known as sacchar-ates. The first of these is produced in presence of an excess of lime; it is soluble in cold water, but nearly insoluble in boiling water, which consequently precipitates it from its cold-water solutions. When thus obtained, saccharate of lime may be washed in hot water without loss, and afterward be again dissolved in cold water. The chemical composition of this saccharate of lime is: Lime, 3 parts; sugar, 1 part. The second compound of lime with sugar is formed when slaked lime is added to a concentrated solution of sugar, until nothing more is dissolved, and to which 85 per cent of alcohol is added. Its chemical composition is: Lime, 1 part; sugar, 1 part. A solution of perfectly pure sugar in pure distilled water will not enter into spontaneous fermentation. This takes place, however, when other organic matter is present, or has been carried to it by the atmosphere, especially if this matter consists of the seeds, or vporea, of cryptogamic plants (mildews). During the process of ordinary fermentation, sugar is transformed into carbonic acid gas and into alcohol. If, however, a neutral solution of sugar be caused to enter into fermentation at a high temperature, lactic acid is also formed. In most cases of fermenting saccharine solutions, 100 parts of sugar are simultaneously converted into Alcohol, 51-612 parts. Carbonic acid, 49240 parts. Lactic acid, 3-948 parts. If a solution of sugar be rich in nitrogenized matter, beside the above, mannite is also produced. The most favorable temperature for fermentation varies between 545 and 995 of the Fahrenheit scale. The more dilute the solution, and the richer it is in albuminous substances, the more rapid will be the fermentation. Beets grown in very fertile lands being richer in nitrogenized constituents than those grown in a poor soil, are also much more liable to produce juice subject to fermentation during their conversion into sugar. The various substances contained in the juice of the beet, other than sugar and water, and which, when possible, must be eliminated before the final termination of the processes of manufacture are as follows: 1. A yellow extract. This is only accidentally met with, in badly-grown beets. We have no mode of ridding ourselves of it, as it passes unaltered through all the processes of defecation, carbonatation and filtration. 2. Silicic acid. This substance forms with lime an insoluble silicate of lime, which is eliminated during defecation, and the subsequent action of the bone black during filtration. 3. Chlorine exists only in a minute quantity in good beets. Its presence is very predjudicial, as it decomposes a certain amount of sugar, and cannot be got rid of by any meant, at our disposal. 4. Phosphoric acid exists in beet root juice, combined with alkalies, which it abandons, to unite with lime, as an insoluble phosphate, which defecation disposes of, 5. Oxalic acid, this also forms soluble compounds with the alkalies, which are decomposed by lime, and transformed into insoluble oxalate of lime. 6. Citric acid forms soluble combinations with alkalies and with lime, and cannot be eliminated during the process of manufacture. 7. 8, 9. The oxides of manganese, iron, and magnesium are mostly separated during defecation as insoluble compounds. 10. Lime. This substance, the value of which is inestimable to beet root sugar manufacturers is also found in the natural juice of the beet. It has the beneficial effect of arresting, to a certain extent, the fermentation of the juice, by its action on the nitrogenized substances contained in it. These last, if left unmolested, transform crystallizable sugar into non-crys-tallizable sugar (also known as glucose, or grape sugar), and thus, largely increase the proportion of molasses. Lime is soluble in 725 parts of cold and 1,300 parts of hot water. It forms by combination with sugar both soluble and insoluble compounds or saccharates. Lime exists in the defecated beet root juice in three states: In solution in water, in combination with sugar, and in combination with acids. A great portion of the lime in the defecated juice is separated by the subsequent process of carbonatation, during which carbonic acid gas cosnbines with it, forming an insoluble pre cipitate of carbonate of lime. After ordinary carbonatation, a portion of lime, along with some soda and potash, still remains in the juice: this quantity does not, however, exceed 0-071 per cent, and is generally less. 11. Soda and potash, which constitute from 70 to to 80 per cent of the weight of the ash of the beet root, are freed from their combinations with acids during defecation, and are thus liberated in a caustic state, which is highly prej udicial, as it decomposes sugar and colors the liquids. Many plans have been proposed.for the elimination of these alkalies from the juice (the best of which appears to be the use of phos-pherlc acid), but none have been generally adopted by manufacturers, and to this day nearly the whole of the soda and potash in the beet root are found again in the residual molasses, from which they can often profitably be extracted by a final technical operation, 12. The albuminous, or nitrogenized substances in beet juice, are coagulated by the action of heat; but as coagulated albumen is soluble in alkaline solutions, and also in solutions of saccharate of lime, a portion of it remains in the juice until the alkalies and the lime have been neutralized. This takes place during carbonatation, when the lime is precipitated along with that portion of the albuminous substances which have not previously found their way into the scums of defecation. Albuminous substances, boiled in alkaline solutions, are partially decomposed, producing ammonia, which is easily recognized by its peculiar smell. During defecation, ammonia is always disengaged. 13. Pectine can only exist in the juice in a solid state, as an abnormal substance, in the shape of minute fragments of beet root or as cellular tissue. The three successive operations of defecation, carbenatation, and filtration through bone black, are at present our only practical means of eleminating most of the extraneous substances contained in the juice of the beet. Our processes are still far from perfect, and much remains yet to be done before we shall have it in our power, to isolate all the ingredients which now find their way into the molasses, or which act detrimentally by converting a considerable portion of crystallizable into non-crystallizable sugar. The importance of separating the various soluble foreign compounds in beet root juice from its contained sugar, may be appreciated by the fact that each per cent of these left in it, is equivalent to a loss of sugar equal to its own weight. Beet root molasses (dripped) contains from 16 to 19 per cent of water, and from 81 to 84 per cent of solid matter. When obtained by the use of centrifugals, however, it contains considerably more aqueous matter than here stated. Beet root molasses can be perfectly dried only when mixed with some kind of finely-divided solid matter, such as sand. The quantity of sugar contained in beet root molasses varies from 30 to over 50 per cent of the whole, or even more. This amount of sugar oonsiBts in a mixture of crystallizable and non-crystallizable sugar in various relative proportions. If the molasses reddens blue litmus paper, it contains none but crystallizable sugar. The quantity of mineral salts in the molasses varies from 14 to 20 per cent of its weight; that of the organic matter, other than sugar, from 10 to 20 per cent. A fair average consists of 25 of water, 43 of sugar, and 32-5 of extraneous matter. The quantities by weight of potash, soda, and lime in the ash of beet root molasses amount, respectively, to 51-72, 8, and 5 per cent, which exist mostly in combination with 25 parts of carbonic acid. I The flavor of beet root molasses is so unpleasantly salt and bitter, that it is not utilized in the raw state for human consumption, but is generally either distilled into brandy or alcohol, fed to farm stock, or even, in some cases, used as a fertilizer. An allowance of 3 to 4 lbs. of molasses per day to a fattening ox, or 1 lb. to a wether, is found to be highly conducive to iapid increase in weight. When given to dairy cows in the proportion of 4 lbs. per day along with beet root pulp and other food, it renders them very productive at a season of the year when provender is scarce and costly. No satisfactory practical method has yet been discovered for separating, on a large scale, the molasses from its accompanying impuriti es, although it is known that a considerable portion of these may be removed by the tedious and expensive process of dialysis, for details of which we must refer the reader to the labors of Graham, Tilloy, Walkhoff, Stammer, and Dubrunfaut. The quantity of mineral salts in molasses may be determined directly, if desired, by Dr. Wielers halometer. All experiments made in regard to isolating the sugar in molasses, in an insoluble form, have failed so far, in an economical point of view, but as sugar combines with barytes, stronthia, lime, and other bodies forming compounds, which are insoluble at the boiling heat of water, and which subsequently can be made to free their sugar.by the action of carbonic acid gas, we h ve good reason for hoping that ere long this desirable result will have been attained. It is well known, that if hydrate of barytes be mixed with sugar in solution.a solid granular saccharate is produced, which precipitates by boiling, and may bo washed clean in hot water. If this saccharato of barytes be dissolved in cold water, and a current of carbonic acid gas introduced in the solution in a carbonatation pan, an insoluble carbonate of barytes is formed and precipitated, and the sugar is set free. This process would be admissible if the barytes, which is highly poisonous, could subsequently be entirely got rid of, which, unfortunately, cannot be done in our daily practice. Strbhthia and lime have been used in the same manner as barytes, the sugar being subsequently washed with alcohol 292 to clear it of extraneous matter. For this purpose 800 lbs. of molasses, 110 lbs. of lime, and 360 quarts of alcohol of 83 to 85 per csnt are stirred together from half to one hour. The saccharate of lime formed is then pressed, and the alcohol, after being run off, is filtered and kept for use again dur. ing repetitions of the same operation. The saccharate is dissolved in cold water, submitted to the action of carbonic acid gas, and the remaing solution filtered, boiled down, and crystallized. About 25 per cent of the sugar contained in the molasses may thus be recovered. When the price of sugar is high, this process may often be profitably practiced. The disagreeable taste of the beet root molasses may be removed to the extent of rendering it palatable, and even very marketable, by simply boiling it carefully with a minute quantity of sulphuric acid, and neutralizing the excess of acid by means of powdered chalk, or limestone. Phosphoric acid has also been used for this purpose, as also for getting rid of the lime, in the shape of a phosphate. The relative quantities of crystallizable and non-crystalliz-able sugar remaining in the molasses, are, in general, rapidly determined by the manufacturer and sugar dealer by means of optical polarization instruments, of which the best are Mitcherlichs and Bentzke-Soleils. Pull instructions for their use i8 furnished along with them to purchasers, for which reason we shall here dispense with a description of these valuable saccharometers. A comparatively exact chemical method for determining the amount of non-crystallizable sugar in sirups and molas-stis is given by Freiling, as follows: 1. Dissolve 40 grammes of pure sulphate of copper in 160 grammes of water. 2. Pot 200 grammes of tartar Tartarus natronatus of druggists) into a small quantity of water, and add 750 grammes of a caustic soda solution of Specific gravity 1-2. 3. Mix the two above solutions. 4. Add water. until the bulk is equal to 11545 cubic centimeters. 5. This forms a blue standard solution, in which 10 cubic centimeters contains oxide of copper sufficient for the reduction of 005 gramme of uncrystallizable sugar. 5. Put 10 cubic centimeters of the above in a clean vessel, and add 40 cubic centimeters of water. 6. Heat to boiling point. 7. Add, drop by drop, a Solution of the sugar or molasses containing not more than 05 gramme of sugar to 100 cubic centimeters of.water, until complete decoloration has taken place, or all trace of. a blue tint has disappeared. A very simple calculation then famishes, as will be seen, the quantity of non-crystallizable sugar in the sample under examination. Let us conclude this dissertation on the chemistry of beet root sugar by remarking that strong acids, such as sulphuric or muriatic, introduced into saccharine solutions of cane or beet sugar, and heatecf to from. 156 to 166 Fah., have the property of converting the whole of the crystallizable into non-crystallizable sugar. In our next article, we shall proceed with the further practical treatment of the juice of the beet root after its car-bonatation has been effected. a Heat of the Stars. The London Mws, in speaking of the heat of the stars, Says : It would scarcely be thought by most persons that the stars supply the earth with an appreciable amount of heat. Even on the darkest and clearest night, when the whole heavens seem lit up by a multitude of sparkling orbs.the idea of heat is not suggested by their splendor. It will, therefore? seem surprising to many that men of science should assign no inconsiderable portion of our terrestrial heat supply to those distant twinkling lamps. It is not many years since Professor Hopkins, of Cambridge, went even further, and expressed his belief that if the earths atmosphere were but increased some 13,000 yards in hight, so as to have an increased power of retaining the warmth poured upon it from outer space.we might do without the sun altogether, so far as our heat supply is concerned. Asa glass house collects the suns heat and renders it available during the time that the sun is below the horizon.so he held that the additional layer of air would serve to garner the warmth of the stars in quantities sufficient for all our requirements. But until lately all these views, however plausible they might have seemed, had not been founded upon facts actually observed. It has been reserved for these days in which discoveries of the most unexpected kind are daily rewarding the labors of our physicists to see that established as a certainty which had before been founded merely upon considerations of probability. Mr. Huggins, the physicist and astronomer, has just published the results of a series of inquiries addressed to the actual measurement of the heat which we receive from the leading brilliants of the nocturnal sky. The instrument called the galvanometer, which has been made more or less familiar to many of us by the researches and lectures of Mr. Tyndall, was made use of by Mr. Hug-gins in these investigations. The instrument was fixed by-Mr. Huggins large refractor.so that the image of a star formed by the eight-inch object glass might fall upon the surface of the thermopile. It will give some token of the care required in researches of this sort to mention that the apparatus had to be left attached to the telescope for hours, sometimes for days, until the needle, whose motion marks the action of heat, had come to perfect rest. When the time came for making an observation, the shutter of the dome, which covers the telescope, was opened, and the telescope was turned upon a part of the sky near to some bright star, but not actually under the star. Then the needle was watched to determine whether the change of position had produced any effect. If, in four or five minutes, no signs of change were shown, the telescope was moved over the small distance necessary to bring the image of the star directly on the face of the pole. Almost always the needle began to move as soon as the image of the star fell upon it. The telescope was then moved slightly away again from the star; the needle was then seen to return to its place. In this way from twelve to twenty observations would be made upon the same star, so that no doubt might remain as to the motion of the needle being really due to the stars heat. In this way, it was found that the bright Arcturus moved the needle three degrees in about a quarter of an hour. So did Regulus, the leading brilliant of Leo, the constellation at present adorned by the splendor of ruddy Mars. Pollux gave a deflection of one and a half degrees; but, singularly enough, his twin brother, Castor, produced no effect at all upon the needle. The splendid Sirius gave deflection of only two degrees; but as this star is always low down, and so shines through a greater proportion of the denser atmospheric strata, it is not surprising that its heat should not be proportioned to its brilliancy.
This article was originally published with the title "Beet Root Sugar" in Scientific American 20, 19, 291-292 (May 1869)