and liberating the sugar in the shape of a perfectly pure solution of sugar in water, of the density of 20 to 23 degrees Baumé; the carbonate of barytes being thoroughly washed is again converted into caustic barytes by burning, so that there is little loss in the operation. The whole process is certainly very beautiful, and its economic working has been tried for a year, on a sufficiently large scale to leave no doubt as to the economy of the process in refining molasses, which is the only purpose it has yet been applied to. The Messrs. Grar were so thoroughly satisfied with it, that when I was there they had taken down their original apparatus, and were re-erecting it on such a scale as to work up all the molasses by it, equal to almost five tons of sugar daily. Owing to this circumstance, I had not an opportunity of seeing the process on a working scale, but was shown the whole proceedings in the laboratory. The only difficulties I see in applying this process at once to the cane juice, are the large quantity of barytes required, the expense of re-burning it and the entire change in works that would be necessary before it could be introduced. The advantage would be, the obtaining the whole sugar contained in the juice, free from all impurities, consequently white, and in the shape of a syrup marking 20 to 23 degrees instead of 8 or 10 degrees, thus saving fully half the evaporation now required. The sugar made in this way, I was told, contains no trace of barytes. To show you the degree of economy practised in such establishments in France, I may mention that the washings of the saccharate of barytes are sold to the makers of potash and soda, who make a profit by boiling them down to obtain what salts they contain. The carbonic acid is obtained by the combustion of charcoal in a closed iron furnace into which air is forced by an air pump, requiring, I believe, about one horse power. From the top of the furnace a pipe leads into a washing vessel, from which the gas is led into the bottom of the vats by pipes.