An absorptiometric rapid determination of niobium in iron and steel by the molybdenum blue method without separating it from the iron, etc., has been studied. The procedure obtained is as follows: Weigh 0.10.5 g sample to a 30 ml platinum crucible, dissolve it with an acid mixture of 10 ml of nitric acid and 5 ml of hydrofluoric acid, carefully add 10 ml of dilute sulfric acid (1+2), evaporate to fumes of sulfuric acid, allow to cool down to room temperature, and add 10 ml of water and 5 ml of hydrofluoric acid (1+50). Transfer the solution to a 100 ml volumetric flask and dilute with water to the mark. Pipet a 10 ml aliquot into a 50 ml volumetric flask, to which add 10 ml of water, 2.5 ml of disodium hydrogen phosphate (0.06%), and 5 ml of ammonium molybdate (2%) by the use of a pipet. Allow to stand for 15 minutes, add 10 ml of dilute sulfuric acid (1+2) quickly; then, 30 seconds after the addition of dilute sulfuric acid, add 4 ml of stannous chloride (0.5%). In measuring the 30 seconds interval, use a stop watch. Dilute immediately to the 50 ml mark with water, measure the absorption with filter S 70. Determine the amount of niobium with the calibration curve. As the presence of more than 0.05 mg vanadium causes erratic results, follow the next procedure: Dissolve the sample with 20 ml of aqua regia, and add 20 ml of perchloric acid (60%); evaporate to fumes of perchloric acid. Cool, and add 200 ml of water, 5 ml of hydrochloric acid, 5 g of sodium sulfite anhydride, and a small amount of ashless paper pulp. Boil the solution approximately for 5 minutes to hydrolyze the niobium, etc.. Digest at 60°C about 30 minutes, filter, wash with dilute hydrochloric acid (2%) several times.
Tranfer the paper and precipitate to the platinum crucible, and ignite at a dull red heat. Treat the oxides with 10 ml of sulfuric acid (1+2), 5ml of nitric acid, 5 ml of hydrofluoric acid, follow the above procedure. The time required for the analysis about was 2530 minutes.

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The sample was fused in alkali, and the fusion product was disintegrated in water. The acidity was regulated with dil HCl, and the mixture was boiled with Na₂S₂O₃ solution for complete precipitation of Ti and separation from Ca and Mg. Two portions of this solution were measured out. One was used as follows: first impurities such as Mn and Fe were separated out by the use of Br₂-NH₄OH, and then the solution was treated with KCN and 10 cc buffer solution to pH 10, and titrated with 0.01M EDTA standard solution, using EBT as an indicator, to give the sum of Ca and Mg. The other portion of the sample solution, after removal of impurities as above was treated with 15 cc 20% NaOH for decomposition of NH₄Cl, and neutralized with HCl; then 10 cc 20% Na₂S₂O₃ and 7N NaOH to pH 13 were added and the Ca was determined by titration with 0.01M EDTA using Dotite NN as an indicator. The amount of Mg was calculated by subtracting the amount required for titration of of Ca from that required for the titration of Ca and Mg.
The standard deviation of error was ± 0.054% for MgO, and ± 0.032% for CaO, and the time required for these procedures was 230 min/sample.

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With an objective in mind of determining bromine and iodine in natural waters, procedures for the determination minute amounts of Br^-and I^- in a large amount of CI^- have been investigated. The sum of bromine and iodine was sought by Kolthoff's method and the amount iodine by Winkler's method. The amount of bromine then was caclulated from the difference. The estimation of 0.021 mg Br^- and I^- in the presence of several thousand times their weight of Cl^- was possible by this method. The presence of a normal amount of Na⁺, K⁺, Ca²⁺, Mg²⁺, Fe, Mn, HCO₃^-, SO₄^2-, etc. in hot spring water or in oil well brine did not interfere. When the sum of bromine and iodine was less than 0.5 mg/l, the solution was made alkaline with sodium carbonate and concentrated by heating on a water bath. The amount of sample solution to be taken for analysis can be determined by its chlorine content since ratio Br/Cl and I/Cl were both found to be almost constant in case of hot spring water as well as oil well brine.

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In order to simplify and speed up the determination of zinc in ore, the authors have developed method which involves the use of an anion exchanger (Amberlite IRA-410) for the separation of zinc from other elements, and the use of EDTA in the succeeding titration. A ver ygood adsorption of zinc is obtained in 0.12N HCl containing 100 g of NaCl per liter. In order to elute the zinc quantitatively, a solution of 1N NH₄OH containing 20 g of NH₄Cl per liter is passed through the column of resin. Metals often associated with Zn in ore, such as Fe, Cu, Mn, Al, and alkaline earths, are not adsorbed on the resin in the HCl-NaCl medium. Although Pb is adsorbed on the resin, can be removed by the usual method. Less than 50 mg of Cd does not interfere with the titration if a small amount of sodium diethyl-dithiocarbamate is added. In general, the ores can be analysed by this method with reliable results (see Table 9). The time required for the analysis is about 45 hours.

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The favourable conditions for the determination of nickel in crude copper have been sought with respect to the composition of supporting electrolyte, the concentration of copper, the temperature of electrolyte, the superimposed voltage, the distance between electrodes, the influence of other elements, and so on.
It was found that nickel together with lead can be determined in the presence of copper with nearly the same conditions as that already reported for the determination of lead in crude copper, except, that a definite amount of lead is to be added to the sample solution in order to diminish the errors caused by the variation of the lead content. The analytical values agreed approximately with those obtained by the usual method (dimethyl glyoxime and D. C. polarography).
The A. C. method was confirmed to be superior to the D. C. method with respect to the shape of wave, and also to be more recommendable than the latter for routine work.

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An oscillo-polarographic method has been applied to the determination of zinc in plant ashes. After an apparatus utilizing a commercial cathode ray oscilloscope had been costructed, oscillopolarograms were observed by Matheson-Nichols' method and by R. H. Müller's method to test the applicability of the appartus. For analytical purposes, the former method is better than the latter. The peak current of the former is proportional to the former method is better than the latter. The peak current of the former is proportional to the concentration of depolarizer.
The ashes of leaves of Prunus salicina Lindl. were analysed by this method. 1.0g of ashes is taken, dissolved in HCl, evaporated to dryness to remove SiO₂, the SiO₂ residue being treated with NH₄Cl+HCl. After dissolving the mixture in water, the zinc is extracted by dithizone-CCl₄ solution, and returned to 0.02N HCl solution. It is then made up to 25ml. 6ml is taken out and an oscillo-polargram is obtained in a supprting electrolyte of NH₄Cl+NH₄OH. colorimetric determination was carried out in parallel and the results of the two analyses showed good agreement. The ashes of normal leaves contained 296 ppm of zinc and those of drug-injured leaves contained 1073 ppm of zinc.

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A rapid and precise determination of thoria in monazite is described. An ARL X-ray Industrial Quantometer was used for this purpose. The analytical procedure is as follows.
Mineral monazites were ground to fine powder and screened through a 250-mesh sieve. Then, they were packed with a spatula in a holder that fitted into a sample-positioning device below the tube window.
The samples were analyzed at 45kV, 30mA, by using a tungsten target X-ray Machlett OEG-60 tube.
A curved LiF crystal and 11-inch spectrometer were used. The calibration curve was made by a linear plot of the intensity of the ThLα₁ line versus weight % of ThO₂. The comparison standards employed were a number of chemically analyzed monazites.
An internal standard procedure using SrKα₁ as the reference line for ThLα₁ was also tried, but no significant improvement in accuracy resulted.
The presence of U₃O₈ up to 2% seemed to give a slightly low value in the analytical results. But such high concentrations of uranium are seldom found in monazited analyses. Moreover, the multi-channel features of this aparatus compensate this effect very easily.

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Uranium forms a yellow colored complex with acetylacetone. It has a definite light absorbancy at pH 6.57. The estimation of light absorbancy with wave lengths of 350370 mμ and the blank of the reagent gave reproducible results. The color system followed Beer's law. The molecular extinction coefficient of an aqueous solution of uranium acetylacetonate (at pH 6.57 with an excess of acetylacetone) was 2560 at 350 mμ and 2220 at 370 mμ. Although there are comparatively many interfering elements, uranium acetylacetonate is an exceedingly stable compound and provides an excellent means for obtaining reproducible results.

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