Eighteenth Annual meeting. 25 



levulose, although recent work seems to show that the ratio between the two varies 

 somewhat with the conditions of preparation. Levulose is said to be slightly sweeter 

 than cane sugar. Dextrose, according to Parmentier, is five-sixths as sweet as cane 

 sugar. If these estimates be true, we should expect invert sugar to be somewhat 

 less sweet than cane sugar. According to the statement of Tucker, ( Manual of 

 Sugar Analysis, page 89,) invert sugar is of rather sweeter taste than cane sugar, 

 and Prof. Henry Morton places the excess at ten per cent. ( Ibid, p. 10.) 



The determination of the sweetness of invert sugar is beset with many difBculties. 

 As it is an uncrystallizable syrup, it cannot be obtained pure by crystallization from 

 its solution. The methods of preparing it given by authorities, are two, viz.: by 

 inversion of cane sugar by heating with sulphuric acid, and afterward removing 

 the acid by means of barium carbonate, or by heating with hydrochloric acid and 

 removing the acid with silver oxide. Solutions of invert sugar prepared by the former 

 method invariably possess a slightly earthy taste, while those prepared by the second 

 method have a disagreeable, metallic taste, due to solution of a small amount of sil- 

 ver oxide. It was suspected that the earthy taste of solutions prepared by the first 

 method was due to barium carbonate. Upon adding a little clear solution of cal- 

 cium sulphate a considerable amount of barium sulphate was precipitated, and by 

 filtering again a solution was obtained which, though not absolutely free from 

 foreign taste, was much superior to that prepared by the unmodified method. An- 

 other difficulty to be met in preparing this substance is the fact that if the acid be 

 allowed to act too long the sugar is changed still further into humus compounds, 

 and if it is not allowed to act long enough the sugar is not all inverted It was found 

 that 40 g. of sugar in 200 cc. of water were completely inverted in twenty minutes by 

 3cc. of concentrated sulphuric acid, without coloring the solution. The tempera- 

 ture was maintained at 75° C. during the whole time. A shorter time may be suffi- 

 cient, as the minimum period was not determined. 



Invert sugar prepared in the manner described was made into solutions of various 

 strength. These solutions were compared with similar solutions of cane sugar. They 

 were submitted to a number of persons, whose opinions as to the relative sweetness 

 of the solutions varied somewhat. Upon the whole, the invert sugar seemed to be 

 about five-sixths as sweet as cane sugar. 



Experiments were also made by cooking a definite weight of Winesap apples with 

 sugar, and comparing the product with that obtained by cooking the same amount 

 of apples and sweetening after the cooking was nearly completed. All precautions 

 were taken to make the experiments strictly comparable. These samples were sub- 

 mitted to various persons, and their opinions as to which was the sweeter were evenly 

 divided. This shows conclusively that for all practical purposes fruit may as well 

 be sweetened before cooking as afterward. Analysis showed that in the sample in 

 which the sugar was cooked with the apples, a large proportion of it was inverted. 

 The cooking was purposely continued much longer than necessary, in order to give 

 opportunity for inversion to take place. 



In my efforts to prepare invert sugar free from foreign taste acquired during its 

 preparation, attempts were made to invert cane sugar in solution by saturating with 

 carbon dioxide. Lippman states that such solutions are entirely inverted in one 

 hundred and fifty hours; but, although the solutions in my experiments were satu- 

 rated with the gas and a slow and continuous current was maintained for eleven days, 

 only a trifling amount of inversion took place. 



