Throughout the Angiosperms the epidermis of the shoot originates from separate initials, which never divide tangentially, so that the young shoot is covered by a single layer of dividing cells, the dermatogen.
This is known as exogenous branch-formation In the root, on the other hand, the origin of branches is endogenous The cells of the pericycle, usually opposite a protoxylem strand divide tangentially and give rise to a new growing-point.
In the Macarthy roller gin, the lint, drawn by a roller covered with leather (preferably walrus hide), is drawn between a metal plate called the " doctor " (fixed tangentially to the roller and very close to it) and a blade called the " beater " or knife, which rapidly moves up and down immediately behind, and parallel to, the fixed plate.
A south pole would be urged oppositely to the conventional " direction " of the line; hence it follows that a very small magnetic needle, if placed in the field, would tend to set itself along or tangentially to the line of force passing through its centre, as may be approximately verified if the compass be placed among the filings on the cardboard.
Resolving normally in the trajectory, and supposing the resistance of the air to act tangentially, (18) v(di/dt) =g cos i, where di denotes the infinitesimal decrement of i in the infinitesimal increment of time dt.