ON THE PROCESS OF CLAYING SUGAR. 83 



thin paste. Part of the water, no doubt, will escape from the 

 superior surface of the clay by evaporation; but by tar the 

 greater part will be distributed over the surface, and gradually 

 descend through an immense number of interstices, forming 

 little currents all over the mass of sugar ; thus increasing the 

 fluidity of the mucus, and favouring its descent towards the 

 apex, where it issues in a single stream into the pot on which 

 the mould stands. To give a more ready issue to the mucus at 

 the apex, a perforation is previously made in the mass by a 

 small spear, called a pricker. 



At the end of several days this clay becomes a dry cake, 

 being deprived of its water, in the manner above described: 

 it is then removed, and fresh diluted clay being put into its 

 place, the operation of washing the mucus from the chrystals 

 recommences. This is repeated, till the loaf becomes sufficiently 

 white, when it is taken from the mould, by gently striking its 

 edge against a block which causes the loaf to fall into the 

 hand ; being then dried in the stove, it becomes ready for con- 

 sumption. 



It is evident that the water contained in the clay on the base 

 of the cone must, in descending to its apex, go on relatively 

 increasing, in proportion to the diminishing surfaces (that is, 

 inversely as the squares of the diameters) through which it pas- 

 ses, till at last it all assembles at a point and is discharged through 

 one hole. It is also evident, that these repeated operations of 

 washing the mucus from the grains or chrystals of the sugar, 

 dissolve and carry off a part of the sugar itself; it is accord- 

 ingly found in practice, that by evaporating the water of the 

 fluid that had hitrcd through the mass, more sugar may be 

 obtained, but the mucus will of course bear a large proportion 

 to the grains; these sirups therefore are generally mixed with 

 the next boiling, and so on, till they at last run from loaves 

 of the lowest quality (called bastards) and finally become 

 treacle or molasses, which will no longer granulate. 



The mould which was at first full, will now contain a loaf 

 of white sugar, the solid contents of which is not more than 

 half o: what it was originally. 



Let Fig. 4. Plate III, represent the section of a mould, in 

 the shape of those at present in use, filled with sugar; it is 



