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We consider the problem of temperature transients in a borehole which has been drilled into an isothermal homogeneous solid and which is flowing at a constant rate. At a fixed time, the temperature of the fluid entering the borehole at the bottom is raised by a given amount. We derive the theoretical expression for the temperature response of the borehole and give a few numerical data of practical value.

The effect of side-wall friction on the uniformity of packing of beds in compression-permeability cells is examined. A large portion of pressure applied to the top of a compressible bad is absorbed in wall friction, resulting in a nonuniformly packed bed. A simplified analysis of wall friction and its effect on porosity and permeability is presented. All experimenters involived in flow through porous media are urged to examine the effects of stress distribution on the structure and uniformity of the packing. In general, compressible beds of small particles will be strongly affected by the walls.

Compression-permeability cells are utilized for measurement of porosity and permeability of compressible cakes. Shortcomings of the cells have tended to be minimized in the literature. Data are presented which show that the stress distribution in typical C-P cells is highly nonuniform because of wall friction. For compressible materials, the porosity and permeability would also be nonuniform. Use of large L/D ratios and minimizing wall friction are essential to proper use of C-P cells.

Working on the snake fish (Ophiocephalus argus, Cantor), we found that its melanophores are under two types of control, one through the pituitary which is regulated by light and darkness, and the other through the sympathetic nerve which is partly adrenergic and partly cholinergic.The Pituitary Control. After removal of the sympathetic chains at the level between the pectoral fin and cloaca, the fish developed, on a white background under the continuous illumination from a lamp of 100 W, a black color over the anterior denervated region. Subsequent enucleation of the eyes intensified this color into coal-black, whereas a previous hypophysectomy would prevent such an appearance. These results indicate clearly that the black color is due to the expansion of the melanophores produced by the pituitary principle whose continuous discharge is increased by darkness,1 and whose effect is accentuated in the absence of the sympathetic influence. Similar results were obtained from frogs (Rana nigromaculata).The Symp...