. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. THE CENTRIFUGED EGG OF CUMINGIA 261 proximately 74 per cent of the total volume of this zone. However, there is probably considerable variation in granule size, and it is not certain how much packing occurs. As an approximation we may take the relative volume occupied by the granules in the broad clear zone as 37 per cent. The concentration of granules at which the viscosity is infinity is assumed to be 74 per cent, though this is probably too high. The equations for the viscosity of a suspension, with the values obtained fo
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. THE CENTRIFUGED EGG OF CUMINGIA 261 proximately 74 per cent of the total volume of this zone. However, there is probably considerable variation in granule size, and it is not certain how much packing occurs. As an approximation we may take the relative volume occupied by the granules in the broad clear zone as 37 per cent. The concentration of granules at which the viscosity is infinity is assumed to be 74 per cent, though this is probably too high. The equations for the viscosity of a suspension, with the values obtained for the viscosity of the hyaline protoplasm of the Cumingia egg, by the use of each, are listed below: = 77 7 (Einstein, from Kunitz, 1926) t] = ' / 1 4- \ -4 ^ (1 ~/)4 (2) T?S = r,(l + ) (Hatschek, 1910) r? = (3) rjs~--- 77— — (Hess, 1920) (3a) 7/s = n- —„ (Hatschek, 1911) r, = (4) r,s= y7 (Smoluchowski, 1916) ry = (1 — j — 6j2jblA)bl (5) r/s = ,, —^ (Bingham and Durham, 1911) 77 - V1 /J where rjs is the viscosity of the suspension (), t] is the viscosity of the dispersion medium, / is the ratio of the volume of suspended particles to the total volume of the suspension (37 per cent), fm is the value of / at which viscosity becomes infinite (74 per cent), and a is a constant. As Kunitz points out, equation (1) is purely empirical. Equation (2) may be applied in cases where / is large. Equation (3), involving the constant a, cannot be applied except by assuming which makes this equation identical with one previously derived by Hatschek (3 a) for very concentrated suspensions (> 50 per cent) of deformable particles. Hess has applied this equation to suspensions of both low and high concentration. Equations (4) and (5) are also empirical. It is not possible to state at present which of these equations applies best to this particular case, so the values calculated are indicative only of the order of magnitude of the viscosity of
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