Tubular Spirit

Some articles on tubular spirit:

Theodolite - Concept of Operation
... This can be tested by aligning the tubular spirit bubble parallel to a line between two footscrews and setting the bubble central ... A horizontal axis error exists if the bubble runs off central when the tubular spirit bubble is reversed (turned through 180°) ... is then set level using levelling footscrews and circular and more precise tubular spirit bubbles ...

Famous quotes containing the word spirit:

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