f being loss of head in feet owing to resistance of nozzle, and v the velocity of the contracted vein in feet per second.
Thirty-five experiments were made with smooth nozzles, resulting in the following formula:
f = 0.0009639 v².
f being the loss of head in feet owing to resistance, and v the velocity of efflux in feet per second.
Experiments show that a prevailing opinion is incorrect that jets will rise higher from ring nozzles than from smooth nozzles.
Box's formula for height of jets of water compares very favorably with experimental results.
IRON PILE PLANKS IN THE CONSTRUCTION OF FOUNDATIONS UNDER WATER.
The annexed engravings illustrate a method of constructing subaqueous foundations by the use of iron pile planks. These latter, by reason of their peculiar form, present a great resistance, not only to the vertical blow of the pile driver (as it is indispensable that they should), but also to horizontal pressure when excavating is being done or masonry being constructed within the space which they circumscribe. Polygonal or curved perimeters may be circumscribed with equal facility by joining the piles, the sides of one serving as a guide to that of its neighbor, and special pieces being adapted to the angles. Preliminary studies will give the dimensions, form, and strength of the iron to be employed. The latter, in fact, will be rolled to various thicknesses according to the application to be made of it. We may remark that the strength of the iron, aside from that which is necessary to allow the pile to withstand a blow in a vertical direction, will not have to be calculated for all entire resistance to the horizontal pressure due to a vacuum caused by the excavation, for the stiffness of the piles may be easily maintained and increased by establishing string-pieces and braces in the interior in measure as the excavation goes on.