1,000 grains of sugar cane, being burnt, gave 7½ grains of ash, which, on analysis, furnished the following components:—
| Silica | 1.78 |
| Phosphate of lime | 3.41 |
| Red oxide of iron and clay | .17 |
| Carbonate of potash | 1.46 |
| Sulphate of potash | .15 |
| Carbonate of magnesia | .43 |
| Sulphate of lime | 6 |
| 7.46 |
The following is the quantative analysis of a portion of soil taken from the surface of a cane field, on the Diamond estate, in St. Vincent, West Indies:—
| Alumina soluble in acids | 12.87 |
| Organic matter | 11.26 |
| Gypsum | .23 |
| Carbonate of lime | 12.52 |
| Carbonate of magnesia | .71 |
| Oxide of iron | 8.51 |
| Oxide of manganese | .33 |
| Insoluble silicious and aluminous matter | 53.57 |
| 100.00 |
The sugar of the cane and grape sugar are distinguished by the following difference in their elements, as proved by analysis:—
| Cane sugar. | Grape sugar. | |
| Carbon | 12 | 12 |
| Hydrogen | 10 | 12 |
| Oxygen | 10 | 12 |
| Water | 1 | 2 |
There is a remarkable difference, however, between their fermentable properties. When a solution is made of the same quantities of these two sugars, in equal proportions of distilled water, it will be necessary to add eight times as much of the same ferment to induce alcoholic fermentation in the solution of cane sugar, as in that of grape sugar. Under the action of a larger quantity of ferment, cane sugar is transformed into grape sugar.
If you cut a sugar cane in two, and examine the interior part of it with a magnifying glass, you perceive the crystals of sugar as distinct and as white as those of double-refined sugar. The object of the operator should be then either to extract those crystals without altering their color, or, if that be found impracticable, to separate them from the impurities mixed with them, while the juice is in its natural state, and yet contains but little coloring matter. Instead of this, the juice is limed while all the impurities are in it. In separating the feculencies from the juice and uniting them in large flakes, lime dissolves a portion of them and forms with them coloring matter, which we all know at once discolors the juice, when lime is used in excess. Afterwards heat is applied, either in clarifiers or in the grand copper, but most of the impurities found in the juice will decompose, and burn at a degree of heat far below the boiling point, say at 120 deg. of Fahrenheit. This is shown by the thick scales continually forming in the grande. From that degree of heat the decomposition goes on in the clarifier till the juice is drawn, and continues in the grande so long as there are feculencies left. This decomposition greatly increases the quantity of coloring matter, so that, as the juice is being clarified, it loses in color what it gains in purity. And here let me show the relative value of the "grande" and of clarifiers as agents of clarification. In the grande, if it is well attended to, the scummings are taken up as soon as they rise. A portion of them is removed before they begin to decompose, and the process goes on, so that before the juice reaches the boiling point nearly all the feculencies are removed, and the source of coloring matter is removed with them. Clarifiers reach the boiling point much quicker, and cannot easily be scummed. The general practice is to bring them to that point without scumming, to let the feculencies separate from the juice by cooling and by rest, and to wash out the clarifiers every second or third time they are filled. Heat and alkalies acting in them upon the accumulated feculencies of one, two, or three charges, dissolve a much larger portion of those feculencies than they can possibly do in the grande. The formation of coloring matter continues during the time of rest, and accordingly planters, after repeated trials, generally agree that juice well clarified in the grande, has a lighter and brighter color, and makes better sugar than that obtained from clarifiers.
The first object of research should be to find means of clarifying the juice without creating coloring matter. It is said that presses something like those used to press cotton, have lately been successfully employed in the West Indies, instead of rollers; that the juice obtained is much purer, and that a much larger quantity of it is extracted from the cane. If so, this will be a great improvement, and the first step of the process I should recommend. From juice thus obtained, I have no doubt that all impurities less soluble than itself may be separated by mechanical means before heat and alkalies are applied, or at least with a very small quantity of alkalies. All other liquids, all fatty substances and oils, except cotton seed oil, are clarified by a very rapid process. Cane juice can no doubt be clarified by similar means, and if this were accomplished the process of sugar making would be very much simplified.
The clarified juice might then be placed in an evaporator, heated by the waste steam of the engine; then be limed and scummed if necessary, and concentrated to fifteen or sixteen of the prese sirop; then purified by filtration through animal charcoal, if white sugar was wanted, or by rest for other qualities; and finally concentrated in vacuum pans of great power, such pans as Mr. Thomas A. Morgan, of Louisiana, now uses, and which, I am informed, are only made in America.