The authors intend to report in the present paper as to the early stage of rapid cooling, the film state boiling, due to quenching of high temperature body. the series of experiments were carried out keeping the conditions of coolants constant inspite of the various conditions of test body. Variety of the conditions was made by changing the initial temperature, surface smoothness and diameter of the test cylinder.
Arranging the data of the experiments, the authors came to the next conclusion.
(1) When the initial temperature was lowered, the coefficient α took the higher value because of the lowering of the durability and the thickness of vapor film.
(2) α can be improved by roughing the surface of test bar, but α may decrease if the grooves on the surface are so deep that the vapor film will not be quickly scraped away.
(3) A decisive result was not obtained for the effects of diameter of test bars on heat-transfer coefficients.

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The characteristics of air-water lift pumps, diameters of which are from about 1cm to 5cm, and lengths of which are from about 1m to 6m, are obtained experimentally. The experimental results are as follows;
1) Lifted water volume Q increases proportionally to submergence σ and air volume V, but the water volume has a maximum value at some air volume for a constant submergence. And the maximum efficiency ηmax is obtained at an intermediate water volume.
Efficiency
Where Q: Lifted water volume (l/s)
ρ_w: Density of water (=1000kg/m³)
h: Head of Lift (m)
P₀: Atmospheric pressure (kg/mm²=mmAq)
V₀: Air volume at atmospheric pressure (l/s)
P_s: Pressure at the foot piece, corresponding to the submergence depth h_s=σ/(1-σ)h, (kg/mm²=mmAq)
2) The longer is total length of a pump pipe, the better are characteristics, but its effect is of small account. On the other hand, the effect of pipe diameter is large.
3) Types of pumps with double pipes and those of pipe enlarging stepwise are not good in per formance, and the roughness of a pipe is not an important factor.
4) When water temperature changes from 15°C to 60°C, the characteristics donot vary.
5) Construction of a foot piece has a large effect.
6) An inclined air lift pump gives a little lower characteristics.
7) When a new air lift pump gives a little lower characteristics.
7) When a new air lift pump is designed, we should select diameter of the pipe for the given water volume from fig. 6, and take a longer pipe length and a larger submergence if possible. The required air volume is to be given from fig. 13.
8) The characteristic curves Q-log V₀ at small volume flow become straight lines. (fig. 11)
9) The total energy loss against V₀ is given in fig. 12, and the curves obtained are straight lines at large volume flow. Kinetic energy of water, which is one of the energy loss, is not negligible as compared with the lifted water horse-power.

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The new specific grinding resistance for ball or tube mills was derived thoretically by the author, utilizing the exponential law considering that there are some doubts concerning to the validity of estimation and experiments previously performed by Mittag.
The results showed that the specific grinding resistances and the mean of those were both inversely proportional to b and xⁿ, and then the former inversely proportional to R, the latter to the logarithmic mean of R, respectively; where b and n were constants x was the Guttman diameter and R was the oversize corresponding to x.
The author explained how to determine the specific grinding resistance chart for the case of ideal grinding, whose results were strictly correlated with the exponential law.
The case affected by buffer-action owing to the very fine powder was also discussed.

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