816
T H E JOL,’RLYAL OF ILL’DUSTRIAL A.VD E-VGIIYEERING CHELZIISTRY.
of other oils to the mineral oil has caused a greater or less diminution in the amount of insoluble and of total residue. The same is also true of the “varnish,” for, as already explained, the apparently high values obtained for No. 5 were caused b y the adherence of the insoluble precipitate t o the bottom of the flask. Considering Nos. 8 to 16, we see t h a t the addition of asphalt increases the percentage of insoluble. This is true even if we correct the figures given in the table b y the amount precipitated b y petroleum ether before the mixture is heated. This is equivalent to 1.35 per cent. calculated on the basis of I O grams of oil. The addition of sulphur, contrary t o expectation, caused no marked difference. The same is true of the addition of paraffin. Linseed oil, as was t o be expected, enormously increased the amount of total residue. The oil which was exposed t o the action of sunlight and air in flasks was, presumably, more completely oxidized than that in the crystallizing dish, for it was in a thinner layer and, besides, the flasks were rotated each day so as to spread the oil on the walls. I t is not surprising t h a t the figures obtained on heating this oil are higher than those for No. 14. The results obtained with the mixture containing ferric oxide are interesting, especially in connection with the statement of Worrall and Southcombe,‘ that the horny or granular deposit a t times found in steam cylinders is Fe,O, or Fe,O, cemented together by oil. One would not expect t o find much rusting in the cylinder or carbureter of a gas engine, but i t is not impossible that the fine metallic powder resulting from the wearing of the piston and of the cylinder walls may become oxidized and then further the carbonization of the lubricant. CONCLUSIONS.
I t has been shown that the addition of various oils and other substances t o a straight mineral oil affects the amount of carbonization, as measured by the percentage of precipitate thrown out by petroleum ether, in various ways. Lubricants containing soap in quantity (see No. 13), rosin and asphalt, or which have been exposed to the action of sunlight and air, are to be avoided. One must not conclude, however, from the low results obtained with mixtures containing tallow, lard oil, etc., that the addition of these oils is t o be recommended. The presence of the fatty acids resulting from the decomposition of the oils may greatly increase the corrosion of the cylinder and in actual practice cause a s much carbonization as the addition of ferric oxide would do. I t is intended in the near future t o make a series of determinations by heating the above mixtures, and possibly others, with polished strips of iron, brass and other metals. B U R E A U OF STANDARDS. WASHINGTON, D.
c.
1
J. SOC.Chem. I d . .
19, 525 (1900).
Nov., 1911
THE FLUORESCENT TEST FOR MINERAL AND ROSIN OILS. E. W. BOUGHTON. Received Sept. 23, 1911.
B y PERCYH. WALKERA N D
The 0ute.rbridge method’ of detecting and estimating mineral and rosin oils in fatty oils, b y taking advantage of the fact t h a t the fluorescence, which is a property of some oils, is very much magnified b y examining the oil in the light of a n inclosed arc, introduces a n entirely new method of oil-testing. The author of this method has made the interesting discovery that samples of oil which in sunlight show no fluorescence, when examined b y the light of an inclosed arc frequently show a very strong fluorescence. He further states that the examination of a large number of vegetable oils failed t o show a trace of fluorescence in any of them, while all samples of heavy mineral and rosin oil, whether debloomed or not, showed strong fluorescence in the proper light. Based upon this observation, he proposes t o rapidly detect and determine mineral or rosin oil in fatty oils b y matching the fluorescence of the oil under examination with t h a t of a prepared set of standard mixtures. Outerbridge’s statement t h a t fluorescence is very greatly magnified b y making the observation in the light of an inclosed arc has been verified in this laboratory. I n addition to the lights used b y Outerbridge, the uviol light was tried but found t o be in no way equal to the inclosed arc, which is far superior for this purpose t o any other source of light. Fluorescence in an oil does not, however, prove the presence of mineral or rosin oil. Of the 1 6 samples of pure linseed oil furnished by Committee D-Iof the American Society for Testing Materials, Nos. 3, 5 , 6, I O , 1 2 , 13, 14 and 16 showed no fluorescence, Nos. I , z and 1 1 showed slight fluorescence and Nos. 4, 7 , 8, 9 and 1 5 showed marked fluorescence. A number of samples of other fatty oils of known purity, some of which were cold-pressed from the seed in the Bureau of Chemistry, showed marked fluorescence, in some cases as marked as t h a t of many pure mineral oils. In order t o test the delicacy of the method, a sample of kerosene, which alone showed very strong fluorescence in the light of the arc, was mixed with linseed oil S o . 3. This mixture, containing I per cent. of kerosene, which could easily be detected b y its odor, showed a slight fluorescence, but it was not so marked as that shown b y linseed oil No. 4 without any addition of other oil. The pure linseed oil No. 3 was then heated to 300’ C. and after cooling was found to be strongly fluorescent. The same development of strong fluorescence was observed in a sample of pure olive oil, which, before heating, showed no fluorescence. The examination of a number of turpentines demonstrated t h a t while many of these samples show no fluorescence, some containing mineral oil also show none, and some samples of undoubted purity show marked fluorescence. I t appears, therefore, that while i t is interesting t o know t h a t the inclosed arc is a very 1 “A Novel Method of Detecting Mineral Oil and Rosin Oil in Other Oils.” B y A. E. Outerbridge. Jr. Proceedings, Fourteenth Meeting American Society for Testing Materials.
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Nov.,
I ~I I
T H E JOLiRiZ‘AL OF I X D U S T R I A L AIVD E,YGI.YEERISG CHEJTISTRY
only that part passing readily being used ; the potash was added in one series as sulphate, in a second as muriate. The mixture contained about 8 per cent, CONTRACTS LABORATORY, of potash and 7.8 per cent. of phosphoric oxide soluble BUREAUOF CHEMISTRY, in water, in addition t o the phosphoric oxide in the WASHINGTON. tankage, which was not determined. The ingredients were thoroughly mixed and portions weighed out NITRIC NITROGEN IN MIXED FERTILlZERS. as follows: Six Io-gram samples on watch glasses, BY S. S. PECK. and twenty-eight 2 . j-gram samples on paraffined Received September 5 . 1 9 1 1 At the 25th annual convention of the Association paper, on watch glasses, half of each lot containing of Official Agricultural Chemists, the referee on the the potash as sulphate and half as muriate. The determination of nitrogen devoted his report t o the weights of all being recorded, one each bf the IOdetermination of nitrogen in mixtures containing gram and two each of the a.5-gram lots were analyzed nitrate of soda. I n neglecting the instructions of a t once. The remainder were set aside for various intervals of time, being covered with large beakers 1906, he apologized by saying:’ “Another phase of the nitrogen .question considered so as t o prevent contamination by dust or insects, last year and discussed in correspondence with the but not hindering the free entrance of air. A further National Fertilizer Association seemed t o outweigh portion of each series was used for the determination in importance and urgency all others, namely, the of moisture according t o the official method. The 2.5-gram samples were analyzed a t intervals determination of total nitrogen in mixed fertilizers to which nitrate of soda is added.” In accordance by the modified Gunning method with the addition with his instructions a number of determinations were of 0.7 gram of mercury. A remarkable irregularity made b y the modified Gunning and Kjeldahl methods was obtained in our nitrogen figures, which we were of mixtures, in which the source of nitrate was a finally able to trace to the imperfect manner in which solution of nitric acid, accurately standardized. The the samples on the paraffined papers were covered results of the different analysts showed wide varia- by the salicylic-sulphuric acid mixture. A second tions, in the words of the author “mostly impos- set of determinations was started, with more regular sible.” I t seems very probable that the divergences results. The final figures in both sets, however, were due to the heat generated by the acid and water, lead to the same conclusions. The ten-gram samples were analyzed as follows: and Trescot expressed in his report to the referee The sample was washed into a beaker and stirred his conviction that on dry samples, the modified in water for about an hour. It was then filtered Gunning method gives correct results. onto a S. & S. paper, the nitrogen in a similar lot of I n the Hawaiian Islands, about 40,000 tons of ferwhich having been previously determined and found tilizer are used annually, a large proportion of which to be negligible in quantity. The entire sample ,consists of high-grade mixtures containing from ‘8 t o I O per cent. of nitrogen from ammonium sulphate, having been transferred t o the paper, it was washed nitrate of soda, and organic sources, principally until the entire leadings amounted to 500 cc. The blood or tankage. The reliability of the modified residue was then dried a t a low temperature, and digested with mercury, sulphuric acid, and sulphate Gunning or Kjeldahl methods is therefore of parof potash. The nitrogen constituted the residual ticular interest to both the fertilizer companies suporganic nitrogen. plying the material and this Experiment Station, Twenty-five cc. portion of the leadings were rewhere samples of a greater part of the shipments t o the. plantations are analyzed. In the latter part of spectively distilled with caustic soda for ammonia last year, complaints were received from a fertilizer nitrogen, and reduced with iron and sulphuric acid company that even when the utmost care was observed for the citric and ammonia nitrogen, according to A like quantity was pipetted in compounding mixtures containing nitrate, ammonia, the Ulsch-Strwt method. into a 500 cc. I
