commenced and finished the period of pressure in just one second. In the cane press about to be described, every one of these open-ended 6 in. lengths would be subjected to intense pressure for a period of two and a-half minutes; in practice, it has been found that the juice was vigorously given out for the first minute, and then gradually declined; finally ceasing to yield one drop more of juice for about half a minute before it was discharged from the open end of the press tube.

In order that this new system of continuous pressure might be fairly tested, I erected a complete press and steam engine combined, at my experimental premises at Baxter House. I also imported a large quantity of canes from Madeira and from Demerara, for the purpose of studying their structure, and making experiments with them, under varying conditions of pressure and time. The quantity of juice which this small apparatus was found capable of expressing exceeded 600 gallons per hour. The juice was much more free from pithy fragments than that which was obtained from the roller-mill, while the quantity of colouring matter and chlorophyl extracted from the knots was much smaller, because in the press these hard knots sank into the softer surrounding parts, while between the rolls they got far more pressure than the softer parts of the cane, because of their greater solidity. But the most important result, which was fully established, was the high percentage of juice obtained.

In our first experiment, made immediately after the arrival of the canes, the quantity of juice obtained exceeded 80 per cent.; in another experimental trial, when the canes had been four months cut, 73 3/4 per cent. was expressed; and, later on, in a public experiment, when the canes had suffered from drying, 65 1/2 per cent. was expressed. In reference to the far smaller quantity of juice obtained in practice by the old system of rolling-mills, I may quote from the Seventh Report of the Parliamentary Committee on Sugar and Coffee Planting, where, at page 259, will be found a memorandum dated "Colonial Laboratory, Georgetown, 3rd February, 1848," from Dr. John Shier, Agricultural Chemist, who -- speaking on Sugar Mills -- says:

From numerous trials on various estates, I am satisfied that the average yield does not exceed 45 per cent.; the first of all improvements then seems to be to obtain a larger percentage of juice from the cane.

It is a curious fact that throughout this competition no one but myself came forward with any plans to do away with the roller-mill. There were plenty of improvements in this class of machine; two rollers and three rollers, new gearing, and combined engines and mills. In one case a magnificent mill had been patented. It was a combined engine and mill, weighing no less than forty tons -- no light matter to pass over half-made Colonial roads -- and it was designed by Messrs. Robinson and Russell, who were large sugar-mill manufactures in London.

The extreme lightness of my cane press formed a strong, and from a Colonial point of view, a most important, contrast to this. The press was put to work, and publicly exhibited to dozens of persons who were owners of sugar plantations in our various sugar-growing Colonies, and great expectations were formed by them. They saw the canes weighed and operated upon, then the squeezed mass again weighed, the reduction in weight clearly showing the quantity or percentage of juice obtained by the press, which was admittedly at least 20 per cent. more than the average produced by the old roller-mills then universally employed. The juice obtained was very rich in quality, in consequence of a considerable evaporation from the canes which had gone on during the three or four months since they were first cut. As a matter of curiosity, I manufactured from the juice obtained about half a hundredweight of crystallised sugar of very good quality, which I presume was the first sugar ever produced direct from the sugar-cane in London, and was much prized as a matter of interest by some of my friends for that reason.

Without going into the minutiae of detail, it may be interesting to give a short description of the cane press, which is here illustrated by engravings copied from drawings of the press, as erected at my experimental works, Baxter House.

The first engraving, Fig. 18, on Plate VIII, shows a side elevation of the press, and the steam-engine with which it was combined, on one large bed-plate.