The reader will form his own conclusions as to the comparative rationality of the two varying statements concerning sugar. According to the chemical doctrine, all is lucid and precise; according to the other, sugar is a kind of organic anomaly. If sugar be a compound of saccharine and crystalline matter, surely an inquirer would infer that either of these matters had been separately obtained, and would, with great justice, expect the sugar community to be able to state the composition, properties, and general nature of sugar, after having been deprived of its saccharine matter. In selecting the purest specimen of a crystallizable body, chemists invariably seek for the largest and best developed crystal, experience having proved that nature avoids admixture of impurities with the substance of a crystal, but extrudes them to the outside, where they form a mere mechanical coating. In conformity with this rule of proceeding, pure specimens of white sugar-candy have been the sta ple material of analytical researches, prosecuted with the result of demonstrating that the composition of sugar is (C12 H10 O10) + Aq. ; and here we must interpose a chemical theory relative to this composition and the reasoning on which it is based. It will be observed, that the eleven parts (atoms or equivalents) of hydrogen, and the eleven of oxygen, would, if combined, constitute eleven atoms or equivalents of water; hence the following question arises :-Does this amount of hydrogen and oxygen, or any part of the same, exist in sugar as water or not? On this point chemists are agreed to consider that one part (equivalent or atom) of hydrogen, and one of oxygen, really do exist in the sugar-candy as water, without which water, or some equivalent for it, the remaining elements C12 H10 10 could not exist in combination. The rationale of this opinion is as follows:--If sugar be brought in contact under favorable circumstances with certain bases-oxide of lead, for instance--an equivalent of water is evolved, and the remaining elements of the sugar (C12 H10 O10) combine with the oxide of lead. In this way the sugar, less one atom of water, may be shifted from one base to another, and its existence inferred. These bases, however, being separated, the C12 H10 O10 immediately resolves itself into other forms of combination; that is to say, provided it have not the means of recombining with the necessary amount of water to form crystalline sugar. Thus water serves as a base, and hence is termed by chemists basic water. Instead, therefore, of stating crystallized sugar to be composed of twelve atoms of carbon, eleven of hydrogen, and eleven of oxygen, or in chemical algebra, C12 H1 On, it is more usual for chemists to represent it as composed of twelve of carbon, ten of oxygen, ten of hydrogen, plus one atom of basic water: or, in chemical algebra, thus: C12 H10O10+ Aq. These observations explain the meaning of the term hypothetical, in contradistinction to practical sugar. The former indicates crystallized sugar minus one atom of water, or (C12 H1 O11) -HO-CH10010, the compound which unites with bases. The latter, this compound plus one atom of water. 11 The non-chemical reader will save himself much trouble and error by remembering this explanation. Otherwise he might hereafter confound the one atom of combined water, with some indefinite quantity of that fluid, in an uncombined state, as constituting moisture. Sugar has a sweet taste, but no smell. Its color is white. When crystallized, it is semi-transparent. It is brittle, and may be easily reduced to powder. Exposed to the atmosphere, it attracts a little water, but incurs no chemical change. Sugar is very soluble in water, which, at a temperature of 480, dissolves its own weight of that substance. With increase of temperature, the solvent power of water for sugar increases also; when nearly at the boiling point, it is capable of dissolving any quantity of sugar whatever. On evaporating the water from a solution of sugar, the latter is obtained in the form of crystals, the primitive form of which is a foursided prism, whose base is a rhomb. The crystals are usually four or six-sided prisms, terminated by two-sided and sometimes by threesided summits. Sugar, like all other organic bodies, is very delicately constituted, and the laws or forces which hold its elements in combination are overcome by the operation of numerous disturbing causes. The action of heat; that of the alkalies-i. e. of all proper alkalies, (the action of alkaloids on sugar has not been investigated;) of a considerable number of non-alkaline bases; and of most acids,-tend to the destruction of sugar, by causing its ultimate elements to fall into a number of new combinations, the major part of which are still but imperfectly known. The following experiment of M. Soubeiran affords a remarkable illustration of the effects produced on sugar solutions by the agency of heat alone. This chemist, having dissolved a given quantity of sugar in a given quantity of water, applied heat to the solution for thirty-six hours. The apparatus was so constructed, that the water given off by evaporation was continually returned to the original solution; by which contrivance the latter was always composed of the same quantity of sugar or its derivatives, and the same quantity of water as when the experiment commenced. Gradually the solution acquired darkness of color, and, at the end of thirty-six hours, it had become black. Hence this experiment teaches us that, even by the application of heat alone to sugar solutions, sugar is destroyed and treacle is formed. Chemists have demonstrated that there scarcely exists a foreign body which, if admixed with sugar solutions, and the latter boiled, does not increase the rapidity of destruction. The alkalies, lithia, potash, soda, and ammonia, act with such energy, that a very inconsiderable portion of either, added to a boiling sugar solution, produces an immediate and visible destruction of a large amount of the latter substance. This destructive agency is also participated in by the alkaline earths, baryta, strontia, and lime. The latter agent is almost universally employed in the manufacture of sugar from cane-juice, and hence arises great destruction of material. Acids, as a class, are equally injurious with alkalies to the constitu tion of sugar. Sulphuric, and hydrochloric acids, convert it rapidly into other compounds, several of which are as yet imperfectly investigated. It would appear, however, that the changes effected by these agents are,-first the conversion of sugar into glucose, then the change of the latter into a series of dark-colored bodies, many of them of an acid nature; amongst which are bodies termed glucic, melasinic, sacchumic, and sacchulmic acids, also sacchulmine, and sacchumine. The action of nitric acid on sugar is peculiar; converting it into oxalic acid. There are certain acids, however, which, under no circumstances that I have been able to recognize, are injurious to the constitution of sugar. Of these, the carbonic and sulphurous acids may be cited. The latter has long been known as a powerful antiferment; and, taking advantage of this property, I was enabled to obtain a specimen of cane-juice from the island of Barbadoes, in a state of such complete conservation, that I extracted from it upwards of 20 per cent. of sugar. Grape Sugar.-Synonyms, sugar of fruit-uncrystallizable sugar (improperly so called)-glucose. The last synonym, i. e. glucose, is that by which grape-sugar will in future be designated throughout these pages. Glucose, so called from yuès, sweet, is that form of sugar, to the presence of which ripe grapes, plums, peaches--and, indeed, the greater number of fruits owe their sweetness. Glucose, moreover, is the sweet principle of honey, and of malt; hence, it is to its presence that brewers'-wort owes its luscious taste, from which liquid it may be procured. The readiest method of obtaining this variety of sugar, in large quantities, is by boiling starch or lignine with water containing a minute portion of sulphuric acid. The best proportions for effecting this are starch one part, water four parts, and of sulphuric acidth of the weight of the starch. The ebullition should be continued for thirty-six hours, the water being returned as fast as it evaporates. At the expiration of this time the conversion of the starch into sugar will be complete; lime now is to be added, which separates all the sulphuric acid in the form of sulphate of lime, and the remaining sugar may be obtained by evaporation. In this operation none of the sulphuric acid used is appropriated by the starch, or enters into any form of combination, its effect being of the kind known to chemists as catalytic, or attributable to contact without combination. This method of forming glucose artificially was accidentally discovered by the Russian chemist Kirchoff, during an attempt to convert sugar into gum. He set out with the idea of dissolving the starch merely in dilute sulphuric acid, but, on continuing the boiling, he noticed the production of sugar. If, instead of starch, cane sugar be used, a similar result is obtained. Cane sugar is also partially changed into glucose by heat alone; and still more rapidly by the united agency of heat and alkalies or alkaline earths. Vogel demonstrated that no gas was eliminated during this trans mutation; and Mr. Moore and De Saussure proved that the quantity of sulphuric used was not diminished in the process. Saussure, moreover, ascertained that 100 parts of starch, when converted into sugar, became 110-14 parts. Hence he inferred, that glucose was merely a solid compound of starch and water, or, more correctly speaking, of the elements of starch and the elements of water. Glucose was, a few years since, largely prepared in the neighborhood of London for the purpose of adulterating colonial sugar, the amylaceous material used in the process being potato farina, of which the chief part was imported from Ireland. It might have been still more economically made, by substituting certain kinds of saw-dust for starch. Glucose, when quite pure, is nearly white, and crystallizes in little needles, radiating from a centre, offering, in the aggregate, the appearance of little tubercular masses. Unlike cane sugar, glucose is soft and clammy to feel; it may also be distinguished from the former by certain chemical tests.* Mannite.-Various species of the ash yield, when incisions are made into their bark, an exudation of glutinous feel and sweet taste. When its fluid portion has been evaporated by the sun, it finds its way into commerce under the name of manna. The bulk of manna consists of a peculiar sugar, which chemists term mannite; and to obtain which from manna, the latter is digested with hot alcohol, which dissolves the mannite. On evaporating away the alcohol, mannite crystallizes in slender acicular tufts. The consideration of mannite would not belong to this treatise, were it not for the circumstance of its occasional artificial production from solutions containing sugar of the cane. Thus Foureroy and Vauquelin demonstrated the existence of mannite in the fermented juice of onions and melons-vegetables which naturally contain sugar of the cane-and, under certain conditions hereafter to be detailed, a portion of sugar in juice of the cane is converted into the same substance. Lactic acid is also a result of the fermentation of sugar under certain circumstances; which seem to be these-the presence of nitrogenous bodies, and the due fermentive temperature. Liebig imagines that the formation of both mannite and lactic acid may be due to the deoxidizing effect of these nitrogenous matters. An examination of the formulæ of the bodies involved in the supposition bespeaks the probability of this view; as also do the circumstances under which saccharine liquids undergo the change; namely, whilst they are still raw, or unpurified from the foreign matters which are derived from their native sources. Thus the juices of the beet and the cane rapidly undergo the change adverted to, but solutions of sugar and water probably never. With the juice of the white beet(betula alba,)-the rapidity of the transformation has often been to me a matter of surprise. * * The notes which Dr. Scoffern appended to the two first chapters of his work are omitted for want of space, but will appear next month. PROGRESS OF OUR GREAT CITIES. 1. NEW ORLEANS. In the last issue of the Review we published a table from the New-Orleans Prices Current, showing the gross receipts of produce at that city, for the year ending the 31st August, 1850, which amounted in value to $96,897,873, the largest aggregate ever shown in its commerce. The receipts were, for As the reader will find, in our previous volumes, full statistics of the city's trade, extending back for a great many years, we will not do further now than continue them for the present year. EXPORTS, 1849-50-DOMESTIC AND FOREIGN. Third Quarter, 1849.... 71,280,65 ....Third Quarter, 1849. Tons cleared. 95,626,84 65,292,571 TONNAGE OF NEW-ORLEANS. Tons entered. 66 Second 66 Fourth 46 Previous year .964,165,69 Total to June 30,. 763,634,58 Total to June 30.. Previous year.. Of the exports of home produce, $33,151,279 were to American ports, or coastwise, and $37,898,277 to foreign ports. The total foreign exports in 1848-9, were, domestic, $36,957,118, foreign products, $654,549. Imports, 1848-9, $10,050,697. We extract the remarks of Mr. Littlefield in relation to the leading staples, &c., of the city, for the past year, and will, in our next, continue his statistics. COMPETITION FOR THE VALLEY TRADE. Having incidentally alluded to Northern enterprise and improvements, we take the liberty to remark, that they constitute a subject of much interest with us, in so far that they are intimations that some degree of emulation should speedily manifest itself in the improvement of our advantages of position, if we would not see our trade yearly escaping from us by new avenues, and our "Great Emporium of the South" sink into a fourth or fifth rate city. Already, as we have above remarked, are the canals and railroads of the North diverting from us large quantities of the rich products of the West, and Carolina and Georgia, and even Alabama, are rapidly pushing forward their lines of railroad, to intersect and draw off from us the cotton and other products of the Tennessee valley. With these examples before us, all tending more or less, in their practical results, to the disadvantage of our own trade, will this community much longer be content to rest supinely upon mere natural advantages, and omit all effort to improve those advantages by such artificial aids as readily suggest themselves to the intelligent observer? We trust not. We hope soon to see the public and our men of capital, aroused to action, and such enterprises as the Tehuan34 VOL. I. |