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We find t h a t coals vary, as we would' naturally expect, in the amount of this volatile non-combustible that is included in the mineral constituents. On the few coals that have been calculated in this manner we find the largest amount t o be as in the table used as a n example. I n this table each I per cent. of ash as weighed equals 1.13 per cent. of ash in the coal unburned. The smallest amount found, I per cent. ash as weighed, equals 1.067 per cent. ash in the unburned coal. It is very probable that further work along this line will show a wider variation than is given above.
filtered barium hydroxide solution. Another wash bottle containing a solution of sodium hydroxide was placed between the barium hydroxide tube and the aspirator, a suction pump. A blank experiment with this apparatus showed no precipitation of barium carbonate after drawing air through for one hour. A repetition of Schwalbe's experiment showed a copious precipitation of barium carbonate. The possibility that this evolution of carbon dioxide might be due to the action of the oxygen of the air upon the heated rosin, aided by the presence of slight traces of spirits of turpentine in the rosin, led to a repetition of the experiment using spirits of turpentine alone instead of rosin. With a specimen of old spirits of turpentine an THE STABILITY OF ROSIN AT SLIGHTLY even heavier precipitation of barium carbonate ELEVATED TEMPERATURES. occurred than with rosin. No question of the B Y CnAS. H. HSRTYAND W. S. DICKSON. splitting off of a carboxyl group could arise here. Received November 16, 1908. A specimen of freshly distilled turpentine showed On heating American rosin to 12o0--14oo C. in a also a precipitation of barium carbonate, but not current of air freed from carbon dioxide, Schwalbel so marked as with the old specimen. obtained a copious precipitate of barium carbonate Having proved that the spirits of turpentine by conducting the gases from the flask in which alone was capable of giving the precipitation the rosin was heated into a solution of barium a current of steam was observed by Schwalbe, hydroxide. He interpreted this as evidence of passed through molten rosin for eight hours in the decomposition of the abietic acid in the rosin order to completely remove all spirits of turpentine. with consequent formation of the hydrocarbon Repeating Schwalbe's experiment with this rosin abietene, and pointed' out the effect such a decomthe precipitation was still observed. Evidently position must have upon the melting point and the presence of slight traces of spirits of turpentine saponification number of rosin. was not alone responsible for the precipitation From evidence obtained during the course of observed. another investigation we were inclined to doubt It remained therefore to determine the possible the accuracy of Schwalbe's interpretation. Acinfluence of oxygen and of moisture on the formacordingly the following investigation was under- tion of carbon dioxide from the molten rosin. taken, the results of which show that rosin which Accordingly, the current of air drawn through the has not been long exposed to the oxygen of the flask was freed first from carbon dioxide by sodium atmosphere can be heated indefinitely a t 140O hydroxide, then dried by passing through sulphuric without showing any evidence of the formation acid. A marked precipitation of barium carbonate of carbon dioxide, provided oxygen and moisture was again observed. Then moist nitrogen was are excluded from the flask in which the rosin is substituted for air. The nitrogen was prepared heated. by drawing air through three wash bottles filled EXPERIMEXTAL. with an alkaline solution of pyrogallic acid. Again At the outset Schwalbe's experiment was re- a precipitation of barium carbonate occurred. peated. For heating the rosin a 2 0 0 cc. Erlenmeyer Finally a current of dry nitrogen was drawn through flask was placed in a beaker containing cotton- the flask and after all air had been expelled the seed oil. The air entering the flask was freed rosin was heated t o 140' and kept at this temperafrom carbon dioxide by being drawn through three ture for seven hours without the slightest prewash bottles filled with a strong solution of sodium cipitation in the tube containing barium hydroxide. The above experiments were carried out onza hydroxide. After leaving the flask the air was specimen of freshly distilled rosin from the oleopassed through a test tube half filled with freshly &sin of Pinus heterophyEZa (Cuban Pine). This leeit. angew. Chem. 18, 1852.
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suggested the possibility that Schwalbe had used SOIL ACIDITY IN ITS RELATION TO LACK OF AVAILABLE PHOSPHATES. a rosin from the oleoresin of Pinus palustris (LongSECOND PAPER. leaf Pine). Accordingly a fresh specimen of rosin BY C. W. STODDART. was prepared from the oleoresin collected from a single tree of this species. On heating the rosin Received October 20, 1908. in dry nitrogen to 140°, again no trace of precipiIn a previous article upon this subject’ it was tation was noticeable. shown that acid soils need a phosphate fertilizer. Finally Schwalbe states that his experiment This fact was noted not only in the work of other was made upon a sample of commercial American men on acid soils but also from field and plantrosin. On heating such a sample in dry nitrogen house fertilizer tests on numerous Wisconsin soils. we found an abundant precipitation of barium Since the publication of the preliminary paper carbonate. further tests have confirmed that statement, Four factors therefore may have entered into with one exception, and that, where a test was the formation of the carbon dioxide observed in made on an acid virgin soil in which no fertilizer Schwalbe’s experiment : first, traces of spirits of need was indicated, as might be expected. turpentine in the rosin ; second, moisture; third, Although there is phosphoric acid present in oxygen in the air conducted through the flask; these soils in sufficient quantity for many crops, and, fourth, oxygen absorbed either by the oleo- it is not available, and hence the soils need phosphate resin previous to distillation or by the rosin on fertilizers. That acid soils do lack available phosstanding in the air. The explanation of a probable phates is a fact, but the question now arises as splitting off of a carboxyl group is demonstrated to a causal relation, if any, between the two conto be erroneous by using a sample of rosin ditions; that is, whether lack of available phosrecently distilled from a fresh specimen of the phates is due to the acid condition of the soil. oleoresin and heating in a current of dry nitro- If this is true, it may be explained as follows: gen. The soil acids act upon the readily available phosAnd yet, paradoxical as it may a t first appear, phates, such as the calcium phosphates, a t a more Schwalbe’s explanation is even more than true ; rapid rate than the normal, neutral, or alkaline not in regard to “American rosin,” but as applied soil moisture, and when once in solution these to the acids of the oleoresin from which rosin is phosphates are readily washed out by heavy rains, prepared. I n .order t o avoid any elevation of or are fixed by iron and aluminum compoundstemperature in the preparation of these acids, that is, are precipitated and rendered unavailable freed from the other constituents of the oleoresin, as insoluble iron and aluminum phosphates. When a specimen of the oleoresin of Pirtus heterophylla there is sufficient lime in the soil to maintain the was dissolved in ether. From this ethereal solution phosphoric acid in the form of calcium phosphate, the potassium salts of the acids were precipitated the plant is able to obtain enough phosphorus by addition of a saturated water solution of potas- for its use, since calcium phosphate is soluble enough sium hydroxide. The crystal broth was mixed to supply the needs of the growing crop. If it with glass wool to render it more permeable to an can be shown by chemical analysis that acid soils extractive, then thoroughly extracted with ether contain more iron and aluminum phosphates and in a Soxhlet extractor. After removal of the last less calcium phosphate than do non-acid soils, traces of ether the salts were dissolved in water, and particularly if they contain a greater ratio the solution acidified with dilute hydrochloric of iron and aluminum phosphates to calcium phosacid, and the precipitated acids washed and dried. phate, there is evidence in favor of causal relationOn heating a specimen of these acids in the ap- ship between acid soils and lack of available phosparatus described above in a current of dry nitrogen phates. the mass melted a t 65O-70’~ immediately evolution I n order to test this matter it is necessary to of carbon dioxide began as shown by the escape find some solvent which will extract the iron and of gas bubbles from the molten mass, and the aluminum phosphates and not the calcium phosheavy precipitation of barium carbonate. phate, and vice versa. I n selecting solvents which UNIVERSITY OF NORTHCAROLINA, will extract these minerals separately from the soil CHAPEL HILL, N. C. 1
Whitson and Stoddart, J , Am. Chem. Soc.. 29, 757.
