105 



The higher effect of your article is perhaps attributable, in consider- 

 able measure, to a more perfect pulverization than that secured in other 

 samples, the degree of this exercising an undoubted influence. As was 

 noticed in the matter of purity coefficient, after the use of some 15 per 

 rent lurther amounts added were out of all proportion to the increase 

 in effect. The power of lignite to absorb or otherwise destroy or re- 

 move is apparently confined to those contained substances producing 

 particular color effects only. For these its affinity is certainly very 

 great, animal char or bone black, in the lower percentages, being found 

 altogether out of comparison with it in this jegard. These colors sup- 

 pressed, however, by a relatively small quantity of the lignite, addi- 

 tional quantities produce but little useful effect, the remaining coloring 

 matters being those for which it possesses little or no affinity. This 

 hypothesis explains the fact that, having used so much as 30 to 45 per 

 cent, to secure rapidity of filtration, the cake from one operation was 

 found to have lost none of its decolorizing power upon a second appli- 

 cation, though it no longer filtered with the same efficiency. Its influ- 

 ence upon the exponent, also, seemed to have diminished little by like 

 previous use upon juice, although considerably more so after the filtra- 

 tion of dense sirups not first treated as juice, a fact possibly finding its 

 explanation on the same lines. Except for the Texas sample, all the 

 coals examined gave up a slight amount of greenish coloring matter, 

 whether boiled in distilled water, juice, or sirup, all showing likewise 

 an acid reaction, your own being most pronounced in the latter par- 

 ticular. 



A hard and apparently very dry cake was obtained with whatever 

 variety of lignite, if employed in amounts above 15 per cent, of the 

 contained sugar, provided only ample time was accorded its formation. 

 It was, however, in all instances of high per cents, exceedingly porous 

 as compared with scum cake finished off at corresponding pressures, 

 weighing per press always in close proximity to the ascertained average 

 of 070 pounds at a final pressure of GO pounds, of which, after lixivia- 

 tiou at 40 pounds pressure, 49 per cent., a little more or less, was moist- 

 ure. . 



Since with a juice polarizing 13 per cent, sucrose some 40 pounds of 

 the latter would be otherwise lost from each pressing, equal to nearly 

 3 per cent, of the entire amount treated, supposing 1,300 gallons of 

 juice jto be put through, with- 30 per cent, of the brown coal, at each op- 

 ,<>n, the importance of lixiviation can scarcely be overstated. No 

 press except arranged for this supplementary process in its most com- 

 plete attainment would, of course, be admissible. This work is too 

 unuuiformly accomplished by steam, by reason of channels at once cut 

 on lines of least resistance, which, besides, leaves the press too hot for 

 immediate manipulation and severely taxes the cloths. Hot water re- 

 sults in too rapid and too great a reduction of the purity coefficient, 

 possibly because of the action of heat upon the solubility of some 

 among the retained impurities. Cold water certainly performed best, 

 all things considered. 



The theoretical amount of so-called displacement water was found 

 altogether inadequate. For a 30-frame Kroog press 200 liters are, for 

 reasons not necessary to state, supposed to be the extreme limit of re- 

 quirement. Thisamount when passedin one hour already a serious loss 

 of time compared with the filtration itself, which consumes but three with 

 30 per cent, of coal gave at iiuishiug-off a sweet-water still running 

 at an average analysis of: solids, 0.77; sucrose, 5.0 ; reducing sugars, 

 0.52; exponent, 73.87. Assuming the 49 per cent, of retained moisture 



