List of timber framing tools. Illustration of carpentry (charpente) in the French EncyclopÃ©die showing hewing, mortising, pit sawing on trestles. Tools include dividers, axes, chisel and mallet, beam cart, pit saw, trestles, and bisaigue . The men talking may be holding a story pole and rule (or walking cane). Shear legs are hoisting a timber. Below, the sticks on the log are winding sticks used to align the ends of a timber.
The problem of plastics. 1  Plastic is a polymeric materialâthat is, a material whose molecules are very large, often resembling long chains made up of a seemingly endless series of interconnected links.
The plastid is a major double-membrane organelle found in the cells of plants, algae, and some other eukaryotic organisms. Plastids were discovered and named by Ernst Haeckel, but A. F. W. Schimper was the first to grant them a clear definition. Plastids are the site of manufacture and storage of important chemical compounds used by the cell. They often contain pigments used in photosynthesis, and the types of pigments in a plastid determine the cell's color. They have a common evolutionary orig