140 CULTURE OF THE SUGAR BEET. 



perforating their rolling surface, so that the juice is caused to pour into 

 the interior, from which it is allowed to escape, as in the presses of 

 Champonnois and Lebee, or the pulp is carried, by means of endless 

 belts of linen or jute, between a series of solid rollers, effecting a grad- 

 ually increasing pressure, as in the presses of Poizot and Manuel and 

 Socin. 



The presses with rolling cylinders having perforated surfaces are 

 modelled after that of Pecquer, who seems to have been the first to ap- 

 ply this system in the industry. In his press the cylinders are partly 

 inclosed within a closed chest, into which the pomace is forced by means 

 of a strong pump. The surface of the cylinder is merely perforated with 

 small round holes, but this was found subject to serious objection on ac- 

 count of the quantity of solid matter that was allowed to pass through 

 with the juice, which it was difficult to remove by means of filters. 

 Champonnois and Lechaume improved upon this press, following the 

 same principle, and covered the surface with longitudinal openings in the 

 direction of the circumference; and into these openings, which are suit- 

 ably prepared to receive it, and passing around the cylinders spirally, tri- 

 angular wire is wound so closely as to present an almost perfectly smooth 

 surface. The openings for the passage of the juice are formed by very 

 slight elongation of the wire, due to the pressure to which it is subjected. 

 As in the Pecquer press, the pomace from the rasp is forced, by means 

 of a strong press, into a close box which covers about two thirds the 

 filtering surface of the cylinders. The axes of the cylinders are inclined 

 about 45 degrees to facilitate the removal of the pulp. 



The LebCe press is based upon the same principle ; the cylinders are 

 partly inclosed, but the filtering surface is of different and perhaps 

 simpler construction. It is made up of a series of movable frames, 

 which may be changed at will, consisting of small narrow bars, about 

 0.05 inch wide, separated from each other by an interval of about 

 0.001 inch. These small bars are soldered together in sets, so that any 

 injury to the filtering surface may readily be repaired. In the Cham- 

 ponnois press the exhaustion of the pulp was not sufficiently complete 

 by means of single pressing, and it was found necessary to resort to 

 double pressing, involving the use of two or three machines to secure 

 continuous operation, but in the Lebee press this work is automatically 

 effected in the same machine, by means of a combination of several cylin- 

 ders. After passing between the first set of filtering cylinders, the pulp 

 passes under a solid cylinder, rolling upon one of the filtering cylinders, 

 after which it is treated with a spray of water, and again passed under 

 solid cylinders, rolling upon another filtering cylinder. By this means 

 the exhaustion is not only accelerated, but it is claimed to be rendered 

 more complete. 



In the .Collette press the filtering surfaces consist of sheets of finely 

 I>erforated copper, fastened only at one end, along the length of the 



