General view of the first gas pressure spinner and windup used during the early stages of nylon production and research at the DuPont Experimental Station in Wilmington, Delaware. The spinning machine consists of a small brass pipe containing nylon chips, with a hypodermic needle attached to the end. To produce a nylon filament, the pipe was heated until the nylon chips melted, after which pure nitrogen gas was fed into the pipe under pressure, causing a thin filament of nylon to squirt out of the needle. After the filament was examined under a microscope for uniformity, the fiber was stretched, or cold drawn, between two rolls rotating at different speeds. Finally, the fiber was wound onto a bobbin, with the pressure of the nitrogen gas used to control the filament's thickness, or denier.