Archimedes' Screw, a device used to raise water from one level to another. An Archimedes' screw consists of a helix, or spiral, fitted inside a cylinder that is open at both ends. In use, the lower end of the device is placed under water at a slant and a handle, attached to the helix, is turned. As the helix revolves, small amounts of water are slowly raised in wells formed by the side of the cylinder and the surfaces of the helix. The Archimedes' screw was developed in ancient Egypt and, it is believed, improved by Archimedes (287?-212 B.C.); it is still used occasionally in the Middle East. The device can also be used to lift loose materials, such as grains.
We love it. We wear it glittering around our necks and sparkling at our ears, wrists and feet. We pass it down to our children and hoard it in secret stashes. Why is this precious metal so prized?
If a drugstore is the equivalent of a 7-Eleven where you can pick up ready-made apple pie pockets, then a compounding pharmacy is your corner bakery where an individual tart is made just for you. But are these specialized pharmacies safe?