| an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle. |
| a screen or mat covered with a dark material for shielding a camera lens from excess light or glare. |
polarographic analysis
in analytic chemistry, an electrochemical method of analyzing solutions of reducible or oxidizable substances. It was invented by a Czech chemist, Jaroslav Heyrovsky, in 1922.
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