Search results
Results from the WOW.Com Content Network
A pet door (also known as a cat flap or dog door) is an opening in a door to allow pets to enter and exit without the main door's being opened. It may be simply covered by a rubber flap, or it may be an actual door hinged on the top that the pet can push through.
A Dutch door with the top half open, in South Africa Woman at a Dutch Door, 1645, by Samuel van Hoogstraten Old half-door in East Crosherie, Wigtownshire, Scotland. A Dutch door (American English), stable door (British English), or half door (Hiberno-English) is a door divided in such a fashion that the bottom half may remain shut while the top half opens.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Steam engines promoted automation through the need to control engine speed and power.. The introduction of prime movers, or self-driven machines advanced grain mills, furnaces, boilers, and the steam engine created a new requirement for automatic control systems including temperature regulators (invented in 1624; see Cornelius Drebbel), pressure regulators (1681), float regulators (1700) and ...