Egyptian screw

BC Archimedes explores the Egyptian screw, later to be known as the Archimedes screw, as described in his work Elements of mechanics ... 

Also with the low-alkali mixtures, more Egyptian Blue crystals were produced when the samples were pelleted by using a screw press than when using hand pressure. 

Figure 13. Laboratory sample (single firings coarse-grained quartz, 0.3% Na20, screw press, 1000 °C 27 h) coarse texture, continuous, hardness 2 Mohs, dark blue. Thefollounng phases can be identified copper oxide (white spots) in calcium silicate matrix (medium gray), Egyptian Blue (white/light gray), and quartz ( rk gray).

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