The sugar exists in the cells of the cane in a state of solution, and is extracted therefrom by pressure. With this, as with other branches of industry, science has of late years stepped in, and has greatly facilitated the process of extraction and manufacture. It may be as well to give here a summary of the processes employed in the preparation of raw sugar: The canes are passed through the mill, and the juice thus extracted from them runs from the mill into a tank, whence it is pumped to cisterns for supplying the _clarifiers_, heated by steam, where it is purified. From thence it is run into _bag filters_, by which the mechanical impurities are removed. It is then run into _charcoal filters_ to remove the colouring matter of the juice. The filtered juice is then run off into tanks and is drawn thence by vacuum into the _vacuum pan_, where it is granulated, and from whence it is finally discharged for packing. When the steam clarifiers are not employed the cane juice is run into a series of pans or _teaches_ over open fires. This apparatus is also known as a “battery,” and forms another method of purification. [Illustration: Stirring Rod. Ladle. Scraper. Crowbar Wrench.] The original crushing apparatus of India was a kind of squeezing mortar, made out of the hollow trunk of a tamarind tree, and worked by a yoke of oxen, the pestle or stamper being a strong beam eighteen feet long, and rounded at the bottom so as to squeeze or crush the canes in the mortar. Mills similar to those used for crushing oil seeds were used—as were also several other forms of apparatus—before rollers were introduced. Stone and iron rollers were first used, with the axes in a vertical position, but the horizontal was soon found to be the more convenient and economical. The importance of a systematic mechanical arrangement appears to have awakened attention during the reign of Charles the Second, for in 1663, Lord Willoughby and Lawrence Hyde (second son of Edward, Earl of Clarendon, High Chancellor of England) associated themselves with one David de Marcato, an inventor, and obtained a patent for twenty-one years for making and framing sugar mills. In 1691, John Tizack patented an engine for milling sugar canes, &c.; but in this, as in the previous case, it is not specified how the mill should be made. Later on in 1721, William Harding, a smith, of London, who had been many years in Jamaica, and was skilled in the manufacture of sugar mills, having observed their imperfections, how that they were chiefly made with large wooden cogs cased with iron, endeavoured while abroad to improve their construction, but failed for want of competent workmen. On his return to London he made models of sugar mills which were approved by the Royal Society. These mills were fitted with cast iron rollers and cog wheel gearing, and were worked by water power; from description they appear to be the type of mills of the present day. Some forty-five years later, Yonge and