in which P is the total rotation observed. Upon now treating the solution of glucose with an excess of an alkaline solution of mercuric cyanide (prepared by dissolving 120 grammes of mercuric cyanide and 25 grammes of potassium hydroxide in 1 litre of water), the dextrose and maltose contained in the sample are decomposed, leaving the dextrine unaffected. A second polariscopic reading is then made, which gives the amount of dextrine present, that is P´ = 193 _d´_, (2) from which the proportion of dextrine is calculated. Subtracting the second equation from the first, we have P - P´ = 52 _d_ + 139 _m_. (3) Both dextrose and maltose reduce Fehling’s solution, the total reduction (R) being the reducing per cent. of the former (_d_) added to that of the latter (_m_). The reducing power of maltose is, however, only 0·62 as compared with dextrine, therefore R = _d_ + 0·62 _m_. (4) Multiplying by 52, we have 52 R = 52 _d_ + 32·24 _m_, and subtract from (3), which gives P - P´ - 52 R = 106·76 _m_, (5) whence _m_ = (P - P´ - 52 R) / 106·76 (6) _d_ = R - 0·62 _m_ (7) and _d´_ = P´/193. FOOTNOTES: [54] It is of interest in this connection to note the recent discovery of a coal-tar derivative, benzoyle sulphonic imide, C_{6}H_{4} <CO/SO> NH, commercially known as “saccharine.” This body possesses about 230 times the sweetening power of cane sugar. It bears, however, no near chemical relation to the sugars, which, for the greater part, constitute hexatomic alcohols. See Amer. Chem. Jour., i. p. 170, and vol. ii. p. 181; also, Jour. Soc. Chem. Indus., No. 2, vol. vi. p. 75. [55] Of 41 samples of molassan, tested in Massachusetts in 1885, 12 contained tin chloride. [56] The average composition of over 100,000 samples of raw cane sugar (mostly Cuban) tested in the United States Laboratory during the past five years, has been as follows:-- Per cent. Moisture 3·0 Ash 1·5 Polarisation 90° [57] The foregoing description of the polariscope was embodied in an article contributed by the author to Van Nostrand’s Engineering Magazine. [58] Journ. Amer. Chem. Soc., i. p. 1. [59] Wiley, Chem. News, xlvi. p. 175. HONEY.