56 



as to easily burn the fat. The residue in the gooch crucible is now dried in an air 

 oven and weighed, the loss in weight being equal to the fat and moisture. The fat 

 having been determined, the moisture is easily obtained by difference. 

 The results by this method, however, are considerably higher than by the Leach 



method often twice as much but there is no difficulty in the analyst duplicating 



his results. Following are some of the figures obtained by this method: 



Comparison of methods for fat determinations. 



DISCUSSION OF RESULTS. 



Comparing the results by the two methods, it is noticed at once that none of those 

 by the new method checks those made by the old method, and it was thought at first, that 

 there might possibly be an error on account of the moisture present in the flour while 

 extracting, the tests by the old method being carried out on dry flour. A large amount 

 of moisture would probably cause some of the sugar-like substances to be extracted . In 

 order to test this point, the following experiments were performed : Ten grams of flour 

 were weighed out in a gooch crucible as before and placed in a large-mouthed bottle, 

 which was closed with a two-hole rubber stopper. Carbon dioxid which had been 

 dried over concentrated sulphuric acid was conducted through the bottle, the same 

 being arranged in a water bath and heated for four days under these conditions. This 

 was then extracted with ether, according to the new method. The results obtained 

 checked exactly those extracted without drying. 



Results obtained by new method on dried and fresh flours. 



The next point considered was to determine if flour dried in carbon dioxid, under 

 these conditions, would give the same per cent of fat as by the new method or would 

 check the old method. Therefore, 2 grams of flour were weighed out in a small test 

 tube with a hole in the bottom, which was closed by an asbestos plug. This was then 

 placed in the bottle described and dried for four days, after which it was extracted by 

 the Leach method, the following results being obtained: 



