196 



been repeatedly employed for the study of the comparative availability of different 

 nitrogenous substances as a source of nitrogen to plants. 



Comparative studies of denitrification and nitrogen-fixation may be made by the 

 same method. It is merely necessary to modify the cultural conditions by the addi- 

 tion of certain substances. In the case of denitrification, for instance, we add a 

 known amount of potassium or sodium nitrate, leach the soil at the end of ten days, 

 and determine the ammonia, nitrite, and nitrate nitrogen in the leachings and the 

 total nitrogen in the residue. The initial nitrogen content of the soil being known, 

 we have the complete data required. 



The methods just outlined may be still further differentiated. We may find means 

 to distinguish the single phases of ammonification as due to urea bacteria, spore or 

 nonspore-forming aerobes, spore or nonspore-fonning anaerobes. In the case of 

 nitrification, we may attempt to distinguish the single phases of oxidation; in the case 

 of denitrification the single phases of redaction; in the case of nitrogen-fixation the 

 aerobic and anaerobic phases of the process. The applications suggested may enable 

 us to gain an insight into the decay processes in the soil, which are imperfectly under- 

 stood at present. Moreover, we shall not only gain in our ability to interpret past 

 reactions as revealed by analysis, but also be enabled to forecast future reactions and 

 quantitative changes of importance to plant food production and its assimilation by 

 the growing crop. 



An interesting paper on the determination of sulphurous acid and 

 sulphites or sulphur dioxid in food products was submitted by Mr. 

 Edward Gudeman. The paper comprised a comparison of the 

 method adopted by the association and a modified method suggested 

 by the author, the modification consisting in driving over the volatile 

 products with low-pressure steam rather than by direct distillation, 

 as in the association method. The steam is generated from distilled 

 water and passed directly into the mass through a glass U-tube. 

 The details of the paper are to be found in the Journal of Industrial 

 and Engineering Chemistry for February, 1909. 



THE POSSIBILITIES OF MUSCOVADO SUGAR AS AN ADULTERANT 

 FOR MAPLE PRODUCTS. 



By R. E. DOOLITTLE and A. F. SEEKER. 



Occasionally there have been presented for entry at the port of New York shipments 

 of a brown-colored sugar from Venezuela designated as ''Melada" or "Melado." The 

 product is generally in the form of rectangular cakes about 1 inch thick by 5 inches 

 long by 4 inches wide. The cakes vary somewhat in color, but in general closely 

 resemble maple sugar in appearance. Their use as an adulterant or substitute for 

 the maple product seemed quite probable, and the finding of a large quantity of this 

 grade of sugar in the factory of a dealer in maple products by one of our inspectors 

 showed the necessity of making a careful examination of the product. We were 

 surprised to find on employing the usual methods for determining the purity of maple 

 sugar that the brown sugar gave practically the same results as does pure maple sugar. 

 These figures, together with those of a pure maple sugar run at the same time, are 

 given in the table: 



