the telescope, so as to follow all movements of the latter which are opened or closed at will by a handle. and to be always parallel to its line of sight. The guard or outer case is of such a form as to present to Beside this, a second needle, which turns round a point the atmosphere, in whichever… … poses of general surveys of land, and for similar operations tion will render these statements perfectly clear. which the air rushes with a force commensurate with the where they are not unlikely to effect some considerable saving The frame, A, is of cast iron securely bolted to a bench. velocity…
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