To prevent the accidental explosion in the reaction between aluminum and various organic halides which was reported in the previous paper, ethers, esters, nitriles, amines and acid amides were utilized as inhibitors of the reaction between aluminum particles and boiling carbon tetrachloride. It was found that they were effective to prolong the induction time of reaction.
It seemed that the inhibitors reacted preferentially with chlorine radical resulting in the extinction of activity to start the chain reaction, or formed some stable additional compound with aluminum chloride to give subsequent destructive effect on its catalytic activity. Inhibiting power of these organic compounds was considered to indicate the measure of the effect of delaying the induction period.
From these results, relation between kind of functional group of organic substances and each inhibiting power was further clarified. The inhibiting power appeared in the reaction were discussed in connection with molecular structure of organic compound and its adsorptive property on the aluminum surface.

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Corrosion resistance test of carbon steel carbo-nitrided in the mixed gas of CO and NH₃ at 550-850°C, were made in air, water, 10% NaCl, 1N NaOH, 0.1N H₂SO₄, HCl, and HNO₃ solution without agitation, by observing the change of weight and surface condition.
The result: -Carbo-nitrided steel, compared with plain carbon steel, had high resistivity in water, air, 10% NaCl, 1N NaOH solution, but low in mineral acids. That treated at 850°C showed poor result due to the precipitation of Fe₃C in surface layer (ε-phase) produced during carbo-nitriding.

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The corrosion rate and effect of electrolytic polarization of various metallic materials dipped in condensed phosphoric acid (CPA) was observed in the range of temperature from 50°C to 300°C.
The result obtained is as follows:
1) Ta is the most anticorrosive material below 200°C.
2) Hastelloy B is fairly good below 150°C.
3) Stainless steel which contains Cr, Ni, Mo and Cu has resistivity in the concentrated CPA below 150°C but is soluble in the dilute CPA.
4) Anticorrosivity of stainless steel can be improved by the anodic polarization process.
5) Duriment, Ti and Zr have not resistivity in the CPA above 100°C.

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A new good method of copper analysis in copper cyanide bath has been developed as follows:
1. Pipette a 1ml sample into 300cc beaker and add 60-70ml of distilled water.
2. Add 1-2ml of conc. hydrochloric acid and boil until the precipitate becomes a pretty white cristal.
3. Cool and add 5ml of ammonia water and 10ml of 5% EDTA Solution.
4. Boil until the white cristal is dissolved, and cool.
5. Add 5ml of ammonia water and transfer the solution to a 100ml volumetric flask.
6. Bring the Solution to the 100ml mark with distilled water and compare the absorption factor of the solution for the wave of 740mμ wave-length with that of distilled water.

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