Howe, Herbert A. (Herbert Alonzo), 1858-1926 · Meadville, Penna., Flood and Vincent · leaf 143
of cast-iron. The lens lieson a table which turns slowly. The tool is moved bytwo wooden rods, each of which is driven by a crank atits further extremity; the cranks are of different lengths,and turn at widely different rates. So complicated isthe motion that the tool never describes the same… … Fig. -Alvan Clarks Workshop. probably too high in certain regions and too low inothers ; these inequalities must receive attention. Aspherometer which will measure 5W00 of an inch is toorude to measure them. The lens is set up on edge in aspecial testing room, where the temperature is notsubject to…
Astronomy
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
