112 



of these upon the weight of canes crushed. So successful throughout 

 has been the routine work in this establishment with skimmings and 

 settlings from all manner of canes and with many modes of defeca- 

 tion, and so small has been at any time the immediate improvement 

 in the purity co-efficient attributable to it, and yet, by comparison, 

 so easy and rapid a second filtration, as to have forced a conviction 

 that in but an exceedingly small part of the total non-sugar resides 

 well nigh the whole difficulty. This probably minute portion of espe- 

 cially refractory material has been traced, as an insoluble, suspended 

 impurity, to raw juice direct from the rolls, which presents in the filter 

 practically all the perplexities encountered after defecation, and may 

 be followed thence quite to the molasses. The microscope has not 

 identified it at 100 diameters. Fermentation fails to remove it. Al- 

 though itself probably inert and harmless, it suffices to render most diffi- 

 cult or altogether impossible a process which, in effecting an immediate 

 improvement, if only of several points in the exponent, would yet suffice 

 before the by-product was reached to add directly or indirectly a de- 

 cided increment to the otherwise possible rendement. Your success in 

 filter-pressing carbonated diffusion juices this season of 1887- 7 88, at the 

 Magnolia Station, leads to the hope that this small part, whatever it 

 may be, is either in great measure eliminated from the artificial juice 

 by diffusion, or else is amenable to chemical treatment (other than 

 carbonation), such as it is reasonable to suppose will not escape ade- 

 quate research. In either case the benefit to accrue would become im- 

 portant to the local industry, the substitution of osmosis for pressure in 

 juice extraction by large central factories now seeming as if eventually 

 inevitable. 



It is proposed by the proprietor that the investigation of this subject 

 shall continue at this place uninterruptedly throughout another season. 

 At his desire I express the hope that it may not be impossible with 

 you to detail a chemist from your department to aid in this search for 

 an improved defecation. It is not to be overlooked how, to the present, 

 your department, in pursuing its inquiries with respect of sugar manu- 

 facture, has neglected altogether the sulphur regimen universally 

 found in Louisiana's practice, excepting only at its previou / chosen 

 station. 



With much respect, sir, I am yours, very truly, 



W. J. THOMPSON. 



Dr. H. W. WILEY, 



Chemist, U. S. Department of Agriculture, 



Washington, D. 0. 



