For example, in a solution of pure sugar of the specific gravity of 1.061.5, or of 1.061 grammes to the litre, I begin first by ascer→ taining the quantity of cubic centimetres of sugar contained in this liquid, and I represent this quantity by x. The specific gravity or density of pure sugar = 1.606; that is, a cubic decimetre of sugar, supposed to be pure and without interstices, weighs 1.606 grammes; an equal volume of water weighs 1000 grammes at 40 centigrade. From these data, I establish the following equation: 606 101.4 cubic centimetres of sugar, what will the 1000 cubic centimetres of tried liquid? Composition in volume of 1000 cubic centimetres of a solution of sugar at 1.061.5 grammes: Sugar, = 101.4 cubic centimetres, - Composition as regards weight of this same litre, of a solution of Water - Sugar 898.6 cubic centimetres 898.6 = 898.6 grammes, 1.061.5 grammes, that is the weight of the litre of the solution of sugar. Sugar,. 15.350 ..84.650 100.000 By acting on a solution of pure sugar at any specific gravity, and in following, step by step, the above method, you succeed in finding the per centage of the sugar with the most rigorous exactness. In making the application of this formula to a sirup made of any canejuice whatever, and to ascertain the quantity of sugar it contains, either the weight or the volume given, it is necessary to deduct the weight of the saline and organic matters contained in this sirup, which matters vary in proportion to the quality and the nature of the cane-juice em ployed. This experience alone can teach. If I apply this formula to a cane-juice of good quality marking 8 Baumé pese-se's, of specific gravity 1.0615 (Louisiana cane-juice,) I find that the matters in solution giving the specific gravity to this juice exists there in the proportion of 15.35 per cent. On the other hand, knowing by analysis that the proportion of saline inorganic matters is of 6.75 per cent. in a juice of the same specific gravity, by the difference I establish the composition of this juice: At page 28, § 11 of his report, Professor McCulloh informs us that a juice of the specific gravity of 1.0843 determined by his method, contained per 100 in weight: Water.... Extractive matter?. .81.36 18.07 0.57 100.00 23. In applying the method just described to this juice, of the specific gravity of 1.0843, and which is beyond all doubt more exact than that used by the professor, we find it to contain: Water... Crystallizable sugar.. Saline and organic matters. .79.396 .20.179 425 100.000 The error in this instance is more than in the richness in sugar; and to make similar mistakes it is not necessary to be a chemist. Another specimen of the manner of arriving at a chemical analysis by Professor McCulloh. Let us permit him again to explain his method in his own language, page 36, paragraph 31. ANALYSIS OF SOME OF THE FECULENCIES CANE-JUICE. CONTAINED IN OTAHEITE (31.)-"For the purpose of ascertaining what is the nature of the greater part of the feculencies contained in cane-juice, and which separate by gentle heat alone, I took a portion of the same from the clarifier, heated to 140° Fahrenheit, and subjected it to analysis, with the following results: "The feculencies, as taken from the pan, were partially dried by exposure to the air, but they were so retentive of moisture that I found it impracticable to dry them thoroughly without heat, which would probably change the combinations of their elements, and was therefore avoided; and when mixed with water, they formed a mucilaginous mass which could not be filtered. A portion of the still moist feculencies being then carefully weighed, was thoroughly washed with alcohol of the strength of 95 per cent., and the mixture subjected to filtration on a counterpoised filter. The solid matter in the filter was gently and freely washed with fresh alcohol, after which is formed a perfectly dry mass, and was equal in quantity to 11.04 per cent. of the original matter treated with alcohol. By evaporation of this alcohol it yielded 1.64 parts of cerosie, and a small portion of an essential oil; it had therefore taken up 87.32 parts of water. Hence, the scum examined is composed of 87.32 per cent. of water, and 12.68 per cent, of dry matter. From these results, united with those of an analysis of the portion insoluble in strong alcohol, I obtained, as the composition of the 12.68 per cent. of dry matter in feculencies, which separate from Otaheite cane-juice by heat alone 1.-Woody fibre, ..... 705 How strange! how did the professor perceive that this was albumen only? 3.-Cerosie, 129 Cerosie being entirely insoluble in alcohol, the professor has mistaken chlorophylle for cerosie!!! 4. Silica,. 5.-Phosphate of Lime, 13 11 There was also phosphate of magnesia with the phosphate of lime! but this the professor did not see. 6-Oxide of Iron, .0.2 Oxide of manganese was also mixed with the oxide of iron-bu the professor was equally blind. 7.-Essential Oil,...... a trace. It is less than nothing-it requires extraordinary vision to perceive it. This is what is called bácler, a chemical analysis. The oxide of iron spoken of by the professor in this case, does not issue from the cylinders of the mill as he supposes. The iron in the state of combination has its existence in the bark of the cane, and even in the juice of all the varieties of cane. How could he arrive at a correct idea of the constitution of the feculencies of canejuice, when he asserts that he collected them before the ebullition of the juice? At that time he had only a part of the feculencies, and it is with this portion of them that he gives us a specimen of what he denominates an analysis!!! Furthermore, how could the professor expect to find alkaline salts in these feculencies, since the cane-juice, however rich it may be, is always acid, and owes this peculiar acid quality to the presence of the phosphate of lime. In the examination which he made of three varieties of canejuice, in the island of Cuba, the professor passes over in silence the saline matters which exist in the juice of all canes, in greater or less proportions, according to the climate where they are cultivated, and at all the periods of their growth. In the cane, the formation of the salts always precedes the formation of the sugar. The cane-juice which he examined in Cuba, contained from 3 to 4 parts in the thousand of these saline matters; that is, consisting of salt of lime, salts of potassium, of magnesia, &c. How does it happen that they escaped his observation? If Professor McCulloh will take the trouble of making chemical investigations on the cane of Louisiana, he will meet with these saline matters in a much greater proportion than in the cane of the West Indies; for this reason, the riper the cane is, the less it contains of these matters. If he wishes to try the cane at all, the joints, in November, for instance, the period or time of grinding, he will find that the juice of the top of the cane contains these saline matters in a proportion of 3 and 4 times greater than the juice taken at the bottom; and that the juice taken from the middle of the cane will yield a very nearly average contents of saline and organic matters. Allow me, sir, to give you, in a few words, an idea of the proportion of saline matters which are found naturally in the cane-juice. I remarked, and in this opinion a great number of planters coincide, that the specific gravity of cane-juice in Louisiana is on an average of 1061.5; that is, that this juice corresponds to 8, or thereabouts, Baumé pese-sels—it is oftener less. I therefore consider 8 as a fair average. A gallon of cane-juice, of this specific gravity, coming from the mill, 1000 gallons of this same juice, of the specific gravity of 1061.5, In the cane-juice of a high degree, namely, of a specific gravity of 1073 to 1093, (cane-juice of the West Indies,) the saline matters, as well as the organic matters, are in a much inferior proportion. By the use of lime-milk in the defecation of the sugar, nearly onethird of the foreign matters are separated; all the other saline matters are concentrated in the sirup; they are met with again in the molasses and in the raw material. A portion of the acid phosphate of lime, the phosphate of magnesia, the hydrated silica, a portion of the soluble organic matters, are removed by the defecation through the milk of lime; all these matters, in a great measure, ascend with the green feculencies. After having been purified by this milk of lime, 1000 gallons of this same juice retains: These 393 lbs. of organic and saline matters, necessarily are found in the cuite. If the defecation was perfect-if the acid phosphate of lime, the phosphate of magnesia, the hydrated silica, the organic matters, could be completely removed by the milk of lime, there would remain about 12 kilogs. 26 of salts of potassium and other matters, in 1000 gallons of cane-juice of the specific gravity of 1061.5, after complete defecation. But it is not possible to introduce the quantity of lime-milk sufficient for the complete defecation, without serious injury to the fabrication, and to the quality of the article; of this, every sugar planter is perfectly aware. I If the sugar planter always obtains molasses, and in large quantities, he must attribute this to the presence of the saline matters. say this, for the most part, the poorer his cane-juice is, the more molasses he collects: because, cane-juice of a poor quality contains a greater proportion of saline matter than a juice of a greater specific gravity. There are, however, some rare exceptions, to which it is useless to allude. The vacuum apparatus, and the new methods which have been carried to the greatest perfection, are not competent to obtain all the crystallized sugar. If the cane-juice did not contain saline matters, it would be easy to crystallize all the sugar it contained; especially by operating in vacuo, and in filtering bone black, because the cane-juice, (juice coming from a ripe cane,) contains crystallizable sugar only. The saline matters, especially the salts of potassium of lime, are always an insuperable obstacle to the total production of the sugar contained in the cane-juice. These matters are not only prejudicial to the crystallization, but they react on the crystallized raw material, and cause a portion to deliquesce during the draining. It is only by liquoring or by terrage you can separate these matters from the sugar. If I were called upon, I could demonstrate, that the sugar (raw material) of Louisiana, contains on an average about one half pound of saline matters per gallon; that the whole quantity of molasses furnished by the draining of one hogshead of raw sugar, contains very often from 25 to 30 pounds of those matters; and that the raw sugar is always impregnated with the same matters. In unfavorable seasons, when the cane-juice marks 7° or 71, this proportion is increased. I have seen, on several occasions, that the cuite required to fill a hogshead, which, with complete draining, will weigh 1000 pounds, contained more than 70 pounds of saline matter. This depends on the quantity of canejuice employed to attain 1000 pounds of raw sugar. Two-thirds of these saline matters run out with the molasses, the other portion remains in the raw sugar, and tends incessantly to drain the sugar, or to cause it to deliquate. The facts which I have placed before you, have not yet been understood by all the planters. When they do understand them perfectly, the state, or rather the planters in a body, can offer a reward of $100,000 to the person who will devise means for the total removal of these matters, previous to the crystallization of sugar; then, and then only, will there be no molasses. It will be not only one of the most magnificent discoveries made in chemistry, but one of the most useful; the services rendered to the planters would be incalculable, and could not be too highly recompensed. To execute this work, and to render it tolerable, the march of the professor was traced out. It is unfortunate for himself, and a matter of regret for the persons interested in this subject, that he did not follow the beaten track, without engrafting any of his own notions and ideas. He had at hand all the discoveries and investigations made on this subject for the last twelve years. From these sources, he could have collected materials which would have enabled him to have written a tolerable book, and one which would have answered the purposes of the American government; at all events, his report would have been less defective. In 1842, Admiral Dupersé, at that time Minister of the Navy and of the Colonies, entrusted to a chemist a similar work. The French chemist, although a man of distinction in his profession, did not fulfil his mandate to the general satisfaction. But, at least, he gave undeniable proofs of his extensive knowledge of chemistry ;-his report containing new ideas and ingenious facts. For these, you would look in vain in the work of the American chemist. This proves to us clearly, that works undertaken by order of government— works ordinarily well paid, are not always the best executed. |