(under the class definition) Apparatus comprising means for cutting the earth which cuts without requiring rotation of the cutting means about an axis coincident with its direction of advance, said cutting means being fed from an inaccessible hole.
(1) Note. For the meaning of "inaccessible hole", see the class definition.
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79, and the search there noted for tool advance guides.
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166, Wells,
100, for a lateral probe sealed against a well wall which has similar structure.