THE SOIL SUPPLY OF NITROGEN FOR PLANTS. By W. O. ATWATER, of Middletown, Conn. [ABSTRACT.] THE nitrogen of the soil, which is the chief source of supply of that material to plants, is subject to more or less loss by the leaching away of nitrates to the lower strata of the soil and thence to rivers and the sea. The best data at present at hand indicate that, in certain portions of the United States, e. g., in New England, a much smaller portion of the total water which comes to the soil thus escapes by percolation than is the case in England and northern Europe. A larger proportion of the summer rainfall is evaporated from the New England soil, and probably, in our longer and colder winter, the freezing of the ground would do more to prevent downward escape of water here than there. Accordingly, other things being equal, we might assume a probability of less loss of nitrogen by the leaching away of nitrates from our soils than from those of northern Europe. If such be the case, our soils, in the regions that have been exhausted by cultivation, might be expected, ceteris paribus, to be the richer in nitrogen. In northern Europe, according to general experience, nitrogenous fertilizers are held to be equally or more important for the increase of crops in ordinary husbandry than phosphatic, potassic, or other mineral manures. So far as the less definitely measured experience of our agriculture indicates, nitrogen hardly appears to assume a position so important relatively to other ingredients of plant-food as is the case in Europe. A series of field experiments with chemical fertilizers, executed by several agricultural colleges and private individuals, upon a plan suggested by the writer, have had for their chief end the study of the effects of nitrogenous materials upon the growth of plants in various soils in New England and other states. The general outcome of these shows a decidedly less relative benefit from nitrogen and more from phosphoric acid, potash, etc., than the teachings of European experience and experiments would lead us to expect. This fact, though in the nature of the cause less definitely attested than strict scientific reliability would require, does nevertheless, so far as it goes, corroborate the assumption that our soils are better able to supply our crops with nitrogen than is the case under corresponding circumstances in Europe, and in lack of better explanation we may not be entirely wrong in attributing the difference, in part at least, to the climatic conditions which produce a smaller percentage of percolation of water of atmospheric precipitation here than in Europe. Our agriculture suffers, in comparison with that of some other regions, through dry weather and more frequent drought. Nitrogen is of immense importance in agriculture and its lack can be supplied only at immense cost. If the hypothesis above suggested be correct, we have in the fact which it explains a partial compensation for the loss which our lack of atmospheric water-supply entails upon us. THE DETERMINATION OF PHOSPHORIC ACID BY THE MOLYBDIC METHOD. By W. O. ATWATER, of Middletown, Conn. [ABSTRACT.] I. EFFECT of presence of organic matter upon the precipitation of ammonium phospho-molybdate. It has been stated (e. g., by Schumann, Fres. Zeit., 14, 301) that phosphoric acid may be accurately determined by precipitation with ammonium molybdate, in presence of organic matter. But analyses are adduced showing that the determination may be materially affected by organic matter, even after treatment with strong nitric acid. The organic matters were found, in a number of cases, to partially prevent the precipitation of the phosphoric acid. II. Precipitation of small quantities of phosphoric acid in the presence of alkaline salts. It has been shown that the precipitation of phosphoric acid as phospho-molybdate is hindered by certain compounds, as hydrochloric acid, sundry sulphates, etc., and aided by nitric acid, ammonium nitrate, and the ordinary solution of ammonium mo lybdate in nitric acid. (See Fresenius, Fres. Zeitschrift, 3, 446; Richter, Dingler's Polyt. Journal, 199, 183, etc.) Sundry experiments were made to test the influence of sodium nitrate upon the determination of minute quantities of phosphoric acid by the molybdic process. It was found that, up to a certain proportion, the presence of sodium nitrate did not hinder the precipitation of even minute quantities of phosphoric acid. This fact has a direct bearing upon the determination of phosphorus in organic substances, since it shows that, when the latter are fused with sodium carbonate and nitrate, and the products of fusion dissolved in nitric acid, the phosphorus can be accurately estimated by the molybdic process. THE DETERMINATION OF SULPHURIC ACID. By W. O. ATWater, of Middletown, Conn. [ABSTRACT.] THIS paper gives results of experiments upon effects of varying quantities of sodium chloride upon the precipitation of sulphuric acid as barium sulphate. The method and results are analogous to those in the previous paper. They bear upon the determination of sulphur in organic compounds in that they confirm results obtained by other experimenters and indicate that sulphur may be accurately estimated by burning the substance in sodium carbonate and nitrate dissolving in hydrochloric acid and precipitating with barium chloride. These experiments have however less interest than the previous ones on the determination of phosphoric acid-since they only confirm generally accepted statements. THE DETERMINATION OF NITROGEN BY THE HYPOBROMITE PROCESS. By W. O. ATWATER, of Middletown, Conn. [ABSTRACT.] A number of experiments were given which indicate that the absorption of nitrogen by the hypobromite solution affects the determination of nitrogen by this process very materially and may account, in part, for the inaccurate results so commonly obtained in determinations of urea by Hüfner's method. THE QUANTITATIVE DETERMINATION OF FATS. By W. O. ATWATER, of Middletown, Conn. [ABSTRACT.] A number of experiments were adduced to show that in the determination of fats in vegetable substances in the ordinary way, the drying, which is sometimes necessary for correct results, may, if conducted in air, lead to serious error. This is probably due to oxidation of the fats by which they are rendered insoluble in ether, carbon disulphide, etc., the re-agents commonly used for extraction. These re-agents are found to extract much more from the same materials dried in hydrogen. TITLES OF OTHER PAPERS READ IN THE PERMANENT SUBSECTION OF CHEMISTRY.1 THE CHEMICAL COMPOSITION AND NUTRITIVE VALUES OF FISH. By W. O. Atwater, of Middletown, Conn. SOME NEW FORMS OF APPARATUS. By W. O. Atwater, of Middletown, Conn. CONSTITUTION OF THE TARTRATES OF ANTIMONY. By F. W. Clarke and Helena Stallo, of Cincinnati, Ohio. DIRECT COMBINATION OF HYDROGEN AND NITROGEN. By W. Colegrove, of Boston, Mass. THE GENESIS OF CERTAIN IRON ORES. By T. Sterry Hunt, of Montreal, Canada. 1 Many of these papers were printed in abstract or in full in SCIENCE, soon after the meeting, and some have been printed in the AMERICAN CHEMICAL JOURNAL, Baltimore. SUBSTITUTION OF CONES MADE FROM PARCHMENT PAPER FOR PLATINUM CONES IN BUNSEN'S PROCESS OF FILTRATION. By L. P. Kennicutt, of Cambridge, Mass. FOREIGN SUBSTANCES IN IRON. By J. L. Kleinschmidt, of St. Louis, Mo. ACTION OF SUNLIGHT IN THE PRODUCTION OF CHLORINATED ADDITION-PRODUCTS OF BENZENE AND NAPHTHALENE, WITH DESCRIPTIONS OF TWO NEW CHLORINE DERIVATIVES OF NAPHthalene. By Albert N. Leeds, of Hoboken, N. J. ACTION OF HYPONITRIC ANHYDRIDE UPON ORGANIC SUBSTANCES, WITH AROMATIC GROUP MONOXYBENZENE, TETROXYNAPHTHALENE By Albert N. Leeds, of Hoboken, ON THE ILLUMINATING GAS OF NEW YORK CITY. By E. G. Love, of New York, N. Y.2 THE SUBSTITUTED ACRYLIC ACIDS. By G. F. Mabery and Mrs. R. Lloyd, of Cambridge, Mass. ON THE ACTION OF VEGETABLE ACIDS ON TIN. By C. E. Munroe, of Annapolis, Md. A MODIFICATION OF BERTHIER'S PROCESS FOR THE VALUATION OF COAL. By C. E. Munroe, of Annapolis, Md. INCRUSTATIONS FORMED IN PIPES USED IN GAS WELLS. By H. B. Nason, of Troy, N. Y. OBSERVATIONS ON THE TEMPERATURE AND CHEMICAL CHARACTER OF THE WATER OF MYSTIC LAKE, MASS., AT DIFFERENT TIMES AND THE VALUATION OF INDIGO. By L. M. Norton, of Manchester, FORMATION OF SULPHOTEREPHTHALIC ACID BY DIRECT OXIDATION. By Ira Remsen, of Baltimore, Md. COMMERCIAL TESTING OF SUGAR, ILLUSTRATED BY SAMPLES OF SUGAR AND INSTRUMENTS USED. By S. P. Sharples, of Boston, Mass. ON A SOLUTION OF FERRIC-GALLATE AND FERRIC-OXALATE AS A REAGENT FOR QUANTITATIVE ANALYSIS OF AMMONIA. By N. B. Webster, of Norfolk, Va. 2 Published in full in THE AMERICAN GAS LIGHT JOURNAL, New York, for Oct. 2, 1880. |