THE ASSAY OF SUGAR HOUSE PRODUCTS. 



piping about nine inches long ; round this is constructed a steam chamber, b, 

 into which exhaust steam from any convenient source is led through the pipe 

 a ; a pipe, c, carries away the condensed water ; the interior of the oven is 

 connected to the last vessel of the evaporator by a half inch pipe, d. 

 One end of the oven is permanently closed, the other end being kept closed 

 when in use by a metal disc, A, on which is fitted a washer of soft material. The 

 external pressure of the atmosphere secures a tight joint, and thumb screws 

 are quite unnecessary ; in an oven of this diameter two shelves can be fitted, 

 leaving room for the insertion of trays not more than half an inch high. The 

 pipe g serves to break the vacuum and it may, if desired, be connected to a 

 vacuum filtering apparatus. A thermometer and vacuum gauge are shown 

 at e and/. 



FIG. 262. 



This type of oven may be obtained from dealers in apparatus, and is 

 essentially similar to that originally described by Carr 1 ; the use of sand is due 

 to Wiley and Broadbent 2 , and filter paper as an absorbent material was 

 suggested by Josse 3 . 



3. From the Refractive Index. It was shown originally by Main, whose 

 results were completely confirmed by Geerligs 4 , that the refractive index of 

 sugar house products is in direct proportion to the true total solids, and that this 

 relation obtains for all products from juice to waste molasses. The instrument 

 most convenient for this purpose is the Abbe refractometer, Fig. 262, with 



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