SUGAR. 213 



acid and deliquescent, besides being charged with salts of the oxide of iron, 

 insomuch that it ordinarily strikes a black color with tea. To remedy these 

 difficulties was the object of my researches; while, at the same time, I was 

 engaged in ascertaining the true composition of the sap, with a view to the 

 theory of vegetable nutrition. 



I received several gallons of freshly-drawn maple sap from Northampton, 

 Warner, and Canterbury, and made analyses of each lot, separating the acids, 

 salts, and the sugar. I also analysed the sap of the yellow and white birch, 

 which do not give any crystallisable sugar, but an astringent molasses. 



I shall now communicate to you the process by which I manufactured sugar 

 maple sap, received from the Shakers of Canterbury, who collected it with care 

 in a clear glass demijohn, and sent it forthwith, so that it came to me without 

 any change of composition, the weather being cold at the time. The evapora- 

 tion was carried on in glass vessels until the sap was reduced to about one-eighth 

 its original bulk, and then it was treated with a sufficient quantity of clear lime- 

 water to rendei it neutral, and the evaporation was completed in a shallow 

 porcelain basin. The result was, that a beautiful yellow granular sugar was 

 obtained, from which not a single drop of molasses drained, and it did not 

 deliquesce by exposure to the air. Another lot of the sap, reduced to sugar 

 without lime-water, granulated, but not so well, was sour to the taste, 

 deliquesced by exposure, and gave a considerable quantity of molasses. 



Having studied the nature of the peculiar acid of the maple, I found that 

 its combinations with lime were excessively soluble in alcohol, so that the 

 yellow sugar first described could be rendered' white in a few minutes, by 

 placing it in an inverted cone open at the bottom, and pouring a fresh quantity 

 of alcohol upon it, and allowing it to filtrate through the sugar. The whitened 

 sugar was then taken and redissolvod in boiling water and crystallised, by 

 which all the alcoholic flavour was entirely removed, and a perfectly fine crys- 

 tallised and pure sugar resulted. Now, in the large way, I advise the folio wing 

 method of manufacturing maple sugar. Obtain several large copper or brass 

 kettles, and set them up in a row, cither by tripods with iron rings, or by hang- 

 ing them on a cross-bar ; clean them well, then collect the sap in buckets, if 

 possible, so that but little rain-water will be mixed with the sap, and take 

 care not to have any dead leaves in it. For every gallon of the maple sap add 

 one measured ounce of clear lime-water, pass the sap into the first kettle and 

 evaporate ; then, when it is reduced to about one-half, dip it out into the second 

 kettle, and skim it each time ; then into the next, and so on, until it has reached 

 the last, where it is reduced to syrup, and then may be thrown into a trough, 

 and granulated by beating it up with an oar. 



As soon as the first kettle is nearly empty, pour in a new lot of the sap, and 

 so continue working it forward exactly after the manner of the West India 

 sugar-boilers. The crude sugar may be refined subsequently, or at the time of 

 casting it into the cones made of sheet iron, well painted with white lead and 

 boiled linseed oil, and thoroughly dried, so that no paint can come off. These 

 cones are to be stopped at first, until the sugar is cold; then remove the stopper 

 and pour on the base of the cone a quantity of strong whiskey, or fourth proof 

 rum. Allow this to filtrate through, until the sugar is white ; dry the loaf, 

 and redissolve it in boiling hot water, and evaporate it until it becomes dense 

 enough to crystallise. Now pour it into the cones again, and let it harden. If 

 any color remains, pour a saturated solution of refined white sugar on the base 

 of the cone, and this syrup will remove all traces of color from the loaf. 



One gallon of pasture maple sap yielded 3,451 grains of pure sugar. One 

 gallon of the juice of the sugar cane yields, on an average, in Jamaica, 7,000 

 grains of sugar. Hence, it will appear that maple sap is very nearly half as 

 sweet as cane juice ; and since the maple requires no outlay for its cultivation, 

 and the process may be carried on when there is little else to be done, the 

 manufacture of maple sugar is destined to become an important department of 

 rural economy. It is well known, by the Eeport of the Statistics of the United 

 States, that Vermont ranks next to Louisiana as a sugar state, producing (if I 

 recollect correctly) 6,000,000 of pounds in some seasons, though the business is 

 now carried on in a very rude way, without any apparatus, and with no great 

 chemical skill ; so that only a very impure kind of sugar is made, which, on 



