56 TlMEHRI. 
At Messrs. Kock's estate, La Belle Alliance, in Louisi- 
ana, Robert's machines were also used, and for some 
weeks kept pace with the boiling house, producing more 
syrup per day than the mill which they replaced. In- 
deed we do not learn that the discontinuance of the 
diffusion process on that estate was due to the failure 
of the cutting machines: we shall see later on to what 
it was due. 
It is obvious that other arrangements besides that of 
the revolving disc are possible. Let us consider what the 
requirements of a good machine are. Evidently, ceteris 
paribus, the length of time a machine can run without 
stopping for re-sharpening is directly proportionate to 
the number of knives, because the more knives there 
are, the fewer cuts does each make. Now in the disc 
machine comparatively few knives can be got in, as they 
converge towards the centre ; unless indeed they are 
made to occupy only the outer portion of the radius, 
when the diameter of the disc becomes excessive for 
knives of an assigned length. In a cylindrical drum on 
the other hand, with the knives occupying the convex 
surface, a large number of knives of unlimited length 
can be got in with a moderate diameter : but here we 
are met with this difficulty — that the slices as they pass 
inside the drum, cling by centrifugal force to its inner 
surface, and cannot be got rid of. An admirable com- 
promise has been contrived by Messrs. JouiN, of Paris* 
and Peay, of Havre, whose machine consists of a trun- 
cated cone (that is a drum larger at one end than the 
other,) or of two such figures placed with their small 
ends together. The large ends are open, the connection 
between the rim and the boss being at the small ends. 
