The width of static mass, the height of summit, the height of tongue end, the difference of these both heights and the angle composed by the surface of falling particles in the mixing zone and horizon in the flow pattern of particles in the cross section of a horizontal rotating cylinder were measured experimentally in order to obtain some informations for the designing and operating of such a cylindrical apparatus. The relations between the measured values of these elements and the volumetric charge ratio of particles in the cylinder F/V and the mixing Froude number N²R/g were analysed. It was examined that these values can be expressed by several simple functions of F/V and N²R/g.
The condition to obtain the similar flow patterns in different cylinders is to give a constant value to N²R/g holding the value of F/V at a constant, was confirmed as an important result of the present work.

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Experimental studies were perfomed on compressibility and tensile strength of wood fiber bed. Experimental woods, Spruce, Basswood, Sennoki and Lauan were defibrated by refiners in dry state. Refiners used were of industrial scale of Bauer type Double Disk Refiner, Bauer type Pressurereized Double DisK Refiner and Asplund type Defibrator.
The compressibility and tensile strength of fiber bed of a given apparent density were found to be expressed as a function of the index of shape of fiber (a′/a) defined in our previous paper.
With the value (a′/a), the effects of wood species and the differences of structure of refiners may be neglected in estimating the compressibility and tensile strength of wood fiber bed.

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The effect of charging methods on the incipient state of packing of various kinds of powders was investigated experimentally. Glass beads, crushed glasses and limestones with various kinds of size respectively were selected as powder samples, and screening with differnt opening mesh sizes, funnel and spatula pouring, the latest as the funnel with infinite opening, were used as charging methods. The results obtained are as follows.
The incipient bulk density (1-ε₀) of the same size particle changes remarkably with the change of the ratio of the opening size (or screen mesh size) D₀ to the particle size D_p, when the ratio is small. And this tendency in appeared to be reversed according to the particle size and there can be found a kind of equilibrium size, of which the bulk density (1-ε₀) is constant irrespective of the ratio of D₀/D_p. This specific size of particle becomes large as the irregularity of particle shape increases. Further when the size in large, the effect of D₀/D_p on the bulk density becomes large as the shape of particle deviates from sphererical.

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Critical considerations on the Zhukovskii's theoretical analysis of the movement of particles on the screening surface with constant-radius circular motion is given.
Following his analysis, Fig. 2 and 3, radius of locus for relative motion of a particle (so-called Zhukovskii's circle) are expressed by eq. (4) for monolayer movement, and eq. (18) for two-layer.
Based on the theory, generally accepted values of R and K, Fig. 4 for commercial sifters is disccussed in Eig. 5, 6 and 7.

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