In commenting upon the above, W. D. Horne remarks that the Pellet method of heating to 105° gives too high results owing to caramelization.

J. E. Halligan, in his method of drying six hours at 104° in a salt-water bath, obtained results agreeing closely with the method of drying 2 grams ten hours at 98°.

Mr. Bryan and Mr. Wedderburn by the method of drying in vacuum to constant weight obtained closely agreeing results, and the figures by this method, according to Mr. Spencer, are in best concordance with the workings of the sugarhouse.

The polarizations of the molasses by the different chemists using various methods of clarification are given in the following table:

TABLE VI.-Polarization of molasses with different methods of clarification.

b Lead not removed prior to inversion (Prinsen-Geerligs method).
Too dark to read.

In the factory method employed by G. A. Spencer in Cuba, one-half the normal weight is made up to 100 cc after clarifying with lead subacetate solution (54.3° Brix), using as little as will give a suitable solution; 50 cc of the filtered

solution are acidulated with dilute acetic acid to decompose the soluble levulosate of lead, and the volume is completed to 55 cc. The polariscopic reading, increased by one-tenth, is multiplied by 2 to give the corrected direct reading. Doctor Spencer states that the direct polarization is always too high when the excess of lead is not removed or neutralized with acetic acid.

In the use of potassium oxalate for removing lead, a number of the analysts experienced the difficulty of turbid filtration. W. D. Horne states that this difficulty can be obviated by the use of a little alumina cream.

The results confirm the observations made on the polarization of the raw sugars, namely, that higher results were secured with the wet subacetate of lead than with the dry and that the lowest results were obtained with the hydrosulphite. The question of the influence of the several clarifying and decolorizing agents has already been discussed under sugar and need not be referred to again here. The variations in the direct polarization of the molasses in each series of experiments show in many instances exceedingly wide variations, a circumstance due largely to difference in the temperature of polarization. These differences, it will be noted, are largely equalized in the calculations of the sugar by the Clerget formula, where the variations between the different chemists are less pronounced. The reverse of this was the case in the analysis of the sugar. The exceedingly large dilution necessary to secure a clear reading (in some cases the results had to be multiplied by 16), of course, magnifies greatly any slight error in the initial observations.

a

Regarding the use of hydrosulphite as a bleaching agent, many of the chemists reported a difficulty in securing a sufficiently clear reading with the use of this substance alone. There appeared to be an insufficient decolorization in some instances, while in other cases there was a redarkening of the bleached solution due to oxidation. Weisberg has recently studied the action of hydrosulphites, and concludes that the action is a double one, first, by means of the free sulphurous acid where the bleaching action is permanent, and secondly, by means of the nascent hydrogen which is evolved, when there is a redarkening of the solution through oxidation. The referee has found that this afterdarkening may be prevented by the use of a new hydrosulphite derivative, sodium sulphoxylate-formaldehyde, sold commercially as Rongalite C. Hydrosulphite bleaches are being used extensively in sugar work just at present, and the effect of these upon the polarization and reducing power of various sugars are points which should be thoroughly investigated by the referee next year. The gravimetric determination of the sucrose in the molasses was made by Mr. A. H. Bryan with the following results:

TABLE VII.-Gravimetric determination of sucrose in molasses by Allihn's, and by Munson and Walker's, method, using different clarifying agents.

The determinations of reducing sugars in the sample of molasses are reported in the following table:

TABLE VIII.-Determination of reducing sugar as dextrose in molasses by Allihn's, also Munson and Walker's, method, using different clarifying agents.

The results confirm the observations in the case of sugar, showing that a large amount of reducing sugars is precipitated by basic lead. The slightly higher result obtained in each instance by the Allihn method as compared with that of Munson and Walker is explained by the greater inverting action of the Allihn solution upon the sucrose.

THE EFFECT OF HYDROSULPHITE AND RONGALITE ON THE POLARIZATION OF DEXTROSE, LEVULOSE, AND SUCROSE.

By A. H. BRYAN.

Solutions of 10 grams of the pure sugars in 100 cc of water were prepared and to aliquot parts (25 cc) were added one-fourth, one-half, and 1 gram of the bleaching agents. When these salts were dissolved by shaking, the solutions were made up to 50 cc with water and polarized immediately. The tubes containing the solutions were set aside and polarized after five hours and again

after standing one day. Care was taken to have all the solutions of the same temperature. The results of polarization are contained in the following table:

Determinations of the effect of sodium hydrosulphite B. A. S. F. and rongalite C. on the polarization of dextrose, levulose, and sucrose.

Hydrosulphite has more effect on the polarization of the sugars than rongalite, and lowers the polarization of dextrose more than that of the other two sugars. With sucrose there is a change in the immediate polarization on the addition of 0.5 gram, but on standing one day, 0.25 gram reduces the rotation. Whether this action is due to an inversion of the sucrose, it is impossible to say at present. With levulose there seems to be a slight increase in the polarization, but in other experiments with this sugar no change in the rotation was noted. Rongalite has a slight action on the rotation of dextrose, but on sucrose and levulose there is apparently no action.

In regard to bleaching, hydrosulphite is much faster than rongalite, but it has the disadvantage that its decolorizations are not altogether permanent, and on standing a very short time sulphur is precipitated, making the liquid too cloudy for a reading. More work along this line is being done at the Bureau of Chemistry.

THE DETERMINATION OF SULPHUROUS ACID IN MOLASSES.

By FRITZ ZERBAN and W. P. NAQUIN.

At the last meeting of the association, in 1906, W. D. Horne called attention to several sources of errors in the provisional official method for the determination of sulphurous acid in foodstuffs when applied to sugar products. In the meantime, the food law has been enacted, and therefore an investigation into this question could no longer be deferred. The different methods that have heretofore been used were studied and compared. The work has not yet been completed, but it was deemed advisable to present the data collected so far mainly for the information of those who have to make determinations of sulphurous acid in sugar products. The work will be published later in full.

The following questions had to be studied: (1) Whether molasses contains any hydrogen sulphid or gives rise to it when boiled in the presence of free acid; and whether hydrogen sulphid and sulphurous acid can be given off

simultaneously without acting upon each other. (2) Whether there is any error due to outside sources (use of gas for heating, rubber for connections, tin for condensers). (3) Whether any volatile substances are given off during the distillation which are apt to be acted upon by iodin; and whether or not iodin is lost by volatilization. (4) Whether the use of a current of carbon dioxid is necessary. (5) Whether the total amount of sulphurous acid dis

tils over with the first half of the distillate.

According to our present knowledge of the composition of the sugar cane and its products most, if not all, of the organic sulphur is in the form of proteid sulphur. By boiling in an acid solution the proteids are decomposed, and so far the following cleavage products containing sulphur have been isolated: Cystin, cystein, a- and ß- thio-lactic acid, thio-glycolic acid, ethylsulphid, methylmercaptan, and hydrogen sulphid. The thio acids mentioned decompose further upon prolonged heating, yielding hydrogen sulphid. The presence of hydrogen sulphid in the distillation products of molasses is therefore to be expected. This was suggested by W. D. Horne and also by Jerome Alexander in a paper on the determination of sulphurous acid in gelatin. The following experiments were performed to decide this question: Fresh cane juice was boiled down to sirup without the use of any chemicals; 100 grams were diluted to 400 cc, 5 cc of glacial phosphoric acid added, and distilled. The distillate was collected in a flask containing de Koninck's reagent for hydrogen sulphid (mercuric cyanid and ammonium chlorid in water). A black precipitate was obtained which after filtration was dissolved in bromin water. The solution gave a precipitate of barium sulphate when tested with barium chlorid. Experiments carried out in a similar manner with silver nitrate and lead acetate solutions gave the same results. After receiving a copy of Doctor Horne's paper, cadmium chlorid was used and our observations could be confirmed. The filtrate from the cadmium sulphid was also tested for sulphur, with positive results. The volatile sulphur which is not in the form of hydrogen sulphid may be due to the volatilization of substances of a mercaptan-like character. We have not been able so far, on account of the small quantities obtained, to identify them or to prevent their determination together with sulphurous acid. Similar experiments were performed with a molasses obtained by the sulphitation process as practiced in Louisiana. Hydrogen sulphid was again obtained, which proves that under the conditions of procedure sulphurous acid and hydrogen sulphid may coexist. It is, therefore, advisable to use a solution of cadmium-chlorid in the determinations, as recommended by Horne.

Gas can be used for heating the distilling flask without any risk. But if it be found necessary to concentrate the distillate, this should be done in flasks with narrow openings. Rubber connections should be avoided as much as possible, especially at that side of the condenser which is connected with the receiver containing iodin or bromin. It was found that the use of rubber may introduce considerable error. When two glass tubes are to be connected with rubber hose the two ends of the glass tubes should touch. In a number of distillations a Kjeldahl condenser with tin serpentines was used, and in this case a slight deposit of sulphur was invariably noticed in the glass tube extending into the receiver. When glass condensers were substituted for those of tin that deposit could not be observed. The deposit is probably due to the interaction of hydrogen sulphid and sulphur dioxid, but the tin seems to play some part in this reaction.

Doctor Horne called attention to the possibility that sugar products like molasses when distilled in acid solution might give off volatile organic substances which are acted upon by iodin. In order to test this question, a sample