VARIETIES OE CANE MILLS. 



75 



return, under the most favourable circumstances, upon 

 18 per cent, sugar contained in the canes as follows : — 

 " 8 per cent, left in the megass ; and of the 10 per cent, 

 expressed, 5 per cent, passes into cisterns, ship's hold, and 

 warehouses, as melasses, leaving only 5 per cent, to meet 

 expenses." 



This agrees with what every planter of observation must 

 have noticed ; for even when canes, after being fully ripe, 

 are ground, giving a juice of a density equal to 12° 

 Beaurne, and containing 22 per cent, of sugar, it requires 

 from 12 to 14 tons of canes to give 1500 gallons of juice, 

 the quantity required to produce a hhd., netting 15 cwt. in 

 the English market, and therefore not yielding to the 

 planter a return of more than 6 per cent, of moist musco- 

 vado sugar, and that often of a very inferior quality. 



It has been proved that the ruinous loss sustained by the 

 imperfect pressure of the mills in common use, can be 

 reduced, by attending to the proper adjustment of the sur- 

 faces of the cylinders, and by decreasing the motion to a 

 regulated rate. The Marquis St. Croix, who tested mills in 

 every possible way, says, — " The effectual power of cane 

 mills is in exact proportion to the slowness of the revolu- 

 tion of the rollers, other things being equal. My mill 

 gave as the result of repeated experiments, 46 per cent., 

 with a speed of 8 revolutions per minute ; while at a speed 

 of %\ revolutions, it gave 70 per cent." 



Dr. Mitchell, in detailing some of his experiments on the 

 same subject, says, — " I tested a windmill in Barbadoes, 



