Characteristic of permeability of molding sand was made clear by inspecting the theoretical aspect which thought the space of molding sand the capillary tube due to comparing with the result of the experiment. Permeability in this report is ability by which viscous fluid is made flow through porous materials.
  The results are as follows ;
 1. The approximate equation showing permeability of molding sand was led as follows ;
    K=0.0087{p³/(1−p)³}{(1−p)^2/3}R²
      p = degree of porosity
      R = radius of green sand (assuming a globe)
 2. The experimental results agreed quantitatively upon the above equation and considerably in quantity.
 3. The more circular the sand, the more the permeability.
 4. Permeability becomes smaller by mixing sand.
 5. Permeabilities of air and water agreed upon the equation.
 6. The results obtaind can be considerably explained by thinking spaces of sand capillary tubes and by calculating head of water which sand absorbs. (M. I.)

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  The author examined cupola operation with special briquette coke and investigated the relation between operative conditions and cupola conditions, the results being as follows :
  1. Combustion ratio ηυ in the cupola furnace is hardly influenced by elemental reactivity, but by the temperature distribution in the cupola furnace.
  2. It is most important not to let the melting zone depress for the maintenance of proper atmosphere in the melting zone greatly affecting the oxidation of molten iron.
  The constant height of the melting zone assures the constant tapping temperature and adequate combustion ratio ηυ.
  3. The height of the melting zone is held constant when a constant coke ratio is maintained for the necessary tapping temperature. The "critical coke ratio", as it might be called, is about 14 per cent in the case of briquette coke for the tapping temperature 1450°C, the blast volume-melting rate ratio being about 18.
  The height of the zone in this case is nearly 1.5 times the inside diameter of the furnace ; the combustion ratio, about 0.65 and CO₂, 16 per cent or so.
  4. The heat efficiency of cupola varies 15 to 70 per cent according to the operative conditions ; with blast volume-melting rate ratio, 18 m³ ⁄ min ⁄ t ⁄ hr ; tapping temperature, 1450°C ; and combustion ηυ, 0.65, the heat efficiency is about 25 per cent.
  The author did not observe a large difference between the operation with briquette coke and the one with Class 1 foundry coke.

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  We have studied the effects of Ti up to 4% on cast iron from the practical view point, checked over the Norbury and Morgan's experiments, and considered the formation of granular and eutectic graphite. The results obtained are as follows :—
  (1) Fluidity is fallen by thp addition of Ti, and residual Ti in cast iron is generally little. Therefore, Ti must be added at least at 1400°C or more.
  (2) Ti does not always promote graphitization ; on the contrary it has a tendency to lower graphitization.
  (3) Even if combined carbon increases above 0.9%, free cementite is not observed in the microstructure, but the mixture of pearlite and ferrite is shown.
  (4) Ti reduces low grade oxides in molten iron, and entirely the composition of sand changes.
  (5) The form and size of graphite is fairly changed by the gas treatments, but it is not intended for practicai use.
  (6) The mechanical properties are good at about 0.5% Ti, and the form of graphite is granular.

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  The size of the gate of thin-wall rectangular diecastings was reported in Rept. 1. Here is reported whether the size of the gate in Rept. 1 will be applied when length of the cavity varies and moreover whether its location is thought in the similar relation of the cavity form.
  This experiment was summerized as followings ;
 (1) In the case of the narrow gate {(W / W) < ½} having vortxes on both sides of a jet, the molten alloy flow is not influenced by length of the cavity. The wider gate {(W / W) > ½} occurs a vortex in flow when length of the cavity becomes shorter. (w : width of the gate, W : width of the cavity)
 (2) The filling rate, in Silumin, is not so far influenced by length of the cavity, and in Babbit No.2 is done much.
 (3) The filling rate is remarkably influenced by the molten metal flow. It becomes worse by confusion of flow or an vortex.
 (4) The gate size reported in Rept. 1 is applied to any length of the cavity.
 (5) The location of the gate on the large side of the rectangle can be similarly thought to one on its small side and its size depends upon Rept. 1.

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  It has been believed by many foundrymen that a part of hydrogen formed at the surface of molten cast iron by decomposition of water in wet air was dissolved in molten metal and some blow holes were caused by this dissolved gas evolving again on solidification and that waste products increased particularly in the rainy season. But as shown in the report (Ⅲ) on the effect of humidity, hydrogan could not be analysed in the evolved gas of molten cast iron and consequently could not be the cause of waste products.
  In this report, hydrogen gas from a bomb was blown upon molten cast iron surface, and next the effects of water in lining materials upon molten cast iron were investigated. In both cases, however, hydrogen was scarcely found in the evolved gases.

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  Here is reported the foundry practice of the large steel casting which is a roll stand weighing 92.5 tons.
  Our practice obtained the following cautions :
  a) Accurate torelance, prevention of shrinkage and a gate should be paid the most care on planning the casting process.
  b) The first problem of the wooden pattern is prevention of its deformation. The divided pattern is recommended and should have the structure not to be destroyed on the remove from the mold.
  c) Silica sand of a large grain is recommended.
  d) The mold should have the strong structure of the flask and the brick lining to bear the large pressure of molten metal.
  e) The core is used the pipe of steel casting to prevent the burn.
  f) With the construction of mold, its parting surface should be prevented the upward penetration by the sufficient weight. (M. I.)

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