Denoting the cross-section a of a filament by dS and its mass by dm, the quantity wdS/dm is called the vorticity; this is the same at all points of a filament, and it does not change during the motion; and the vorticity is given by w cos edS/dm, if dS is the oblique section of which the normal makes an angle e with the filament, while the aggregate vorticity of a mass M inside a surface S is M - l fw cos edS.
Hence if dS and dS' are the areas of the ends, and +E and - E' the oppositely directed electric forces at the ends of the tube, the surface integral of normal force on the flux over the tube is EdS - E'dS' (20), and this by the theorem already given is equal to zero, since the tube includes no electricity.
Under Britishrule Colombo has shared in the prosperity brought to the island by the successive industri e s of coffee and teaplanting.
The formula employed by P is "and Pharaoh's heart was strong (pin)," or, "and Pharaoh made strong (p'in) his heart," as in E, but it is distinguished from E's phrase by the addition of "and he hearkened not unto them as Yahweh had spoken."
It was owing to the combination of this latter account with E's further description of the striving of the people for water at Meribah that the double name Massah-Meribah arose, xvii.
