The Japanese people seem to have acquired knowledge of iron very early. in their history, for certain references are found in our ancient mythology. In middle ages, the art of swordmaking reached such a stage of distinction as to win for the Japanese blades an intemational fame. Technical skill in the manufacture of iron also progressed as the metal became more popular, and its utility extended to the making of farm implements, household utensils, helmets, armour and other forms of armament.
In those remote days, the iron and steel makers were dependent on iron sand for their raw material, which was found chiefly in the province of Sanin and Sanyo. Their practice of smelting iron was very crude and primitive in method, going little beyond the stage of domestic industry carried on in little individual blacksmith shops, However, the Meiji Restoration marked the beginning of a new era in the iron and steel industry of Japan, as it did in many other phases of our national life, and iron for industrial purposes came into keen demand; this situation gave birth to not a few enterprises in the iron and steel industry. First, blast furnaces of modern type were installed at Kamaishi, and Military and Naval Arsenals were constructed. Smelting, forging and casting of iron on modem lioes began to appear on many sides in response to the demand of the times, but the steel works were chiefly engaged in the making of special steel of high order, and our produetion in commercial steel fell far short of requirements. It was not until the Imperial Steel Works at Yawata had been brought into existencein 1897 that the situation was met more or less adequately. The Yawata Steel Works have, since the beginning, been enlarged no less than 3 times, apd we are now given to understand that the annual output of steel products will be increased to one million tons beforelong.
The establishment of the Imperial Steel Works at Yawata was followed by the erection of many private steel works throughout the country. At preseut, the entire demand of our country for iron and steel may be estimated at 2, 500, 000 tons ereyear.
In explaining our situation as regards the future of the industry which is in a vigorous state of growth, it will be well to describe the existing conditions of resources with reference to the requisite raw materials, especially Iron ore & coal, and the equipment of the principai iron and steel works.
In surveying the condition of iron sand smelting in Chugoku provinces and the history of the steel works at Yawata and Kamaishi, a fairly good idea may be formed of the course the industry has followed in its development.
In the last chapter the condition of research and ducational organs, as well as the economic organization, of the iron and steel industry in Japan are described.

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A tabularised report on the dimensions and the operating conditions of the various Japanese open hearth furnaces (22 basic open hearth furnaces, 7 acid open hearth furnaces and a Talbot furnace) was published in vol. XIV, no. 3 of this journal (March 25, 1928). That report requires some corrections and some additional data which seem important and were not yet collected for that report. The authors were able to correct and supplement that report after having secured the necessary data from the steel works with which the above report was concerned.
Referring to the corrected and supplemented report the authors tried the statistical surveying of the construction and operation of the Japanese basic and acid open hearth furnaces. They also compared the construction and operation of the Japanese basic open hearth furnaces with those of the German. The data for the German basic open hearth furnaces were taken from the tabularised report of German basic open hearth furnaces published by Dr. H. Bansen (Stahl und Eisen, No 14, 1925, Tables 14 to 18). Another statistical report of the Japanese open hearth furnaces was pullished alout ten years ago by Dr. K. Tawara and Dr. T. Mishima in a metallurgical report of the Tôkiô Imperial University (1920). By means of this paper the authors compared the construction and operation of present Japanese basic open hearth furnaces with those ten years ago.

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The writer measured the single potential differences between nitrified or nonnitrified special steels containing chromium, aluminium, titanium and zirconium and distilled water, sea water, saturated copper sulphate solution and normal ferrous sulphate solution. He found that special steels, when nitrified, become nobler about 0.6 volt in distilled water and abont 0.2 volt in sea water, but become baser about 0.07 volt at first and finally about 0.03 volt in normal ferrous sulphate solution. In saturated copper sulphate solution nitrified special steel has a positive potential of 0.19 volt. In distilled water nitrified steels become black but never rusty to form red hydroxide of iron (passive state). In normal ferrous sulphate solution, nitrified steels, Rpntaining no elements that produce great hardness, (except 0.3%, carbon steel) show at the begining of their time voltage curves the positive potential of 0.1 volt and become slightly baser (without exception) about 0.04 volt instead of 0.03 volt. Considering the above facts, the special elements to be added to produce great hardness may prevent the outside brittle layer from being produced and small particles of iron may be produced in the outer layer of steels as the result of nitrification.

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