ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
645 
employed for a short time by Oberhauser, circa 1840*; but rackwork 
was first applied to the draw-tube by Benj. Martin, circa 1780. The rack- 
Fig. 150. 
See Quekett on the Microscope, 1st ed., 1848, p. 326. 
