. The microscope and its revelations. -H FIG. 126.—Campbellsdifferential screwfine adjustment(1886).. Fit;. 127.—Zeisssusual new fine adjustment (1880) twenty turns to the inch, whilst the screw thread T causes thetravelling socket H to move in the reverse direction at the- rate oftwenty-five turns to the inch. The combined effect, therefore, ofturning D twenty revolutions is to raise or lower T, and with it thebody-tube -l-th of an inch, or 1-^-oth of an inch for each spiral spring below H keeps the bearings in contact. Of course any desired speed can be attained by prop
. The microscope and its revelations. -H FIG. 126.—Campbellsdifferential screwfine adjustment(1886).. Fit;. 127.—Zeisssusual new fine adjustment (1880) twenty turns to the inch, whilst the screw thread T causes thetravelling socket H to move in the reverse direction at the- rate oftwenty-five turns to the inch. The combined effect, therefore, ofturning D twenty revolutions is to raise or lower T, and with it thebody-tube -l-th of an inch, or 1-^-oth of an inch for each spiral spring below H keeps the bearings in contact. Of course any desired speed can be attained by proper combina-tion of the threads: thus 32 and 30 would give ^cfth of an inchfor each revolution, and 31 and 30 would give -g-j^th of an inch. This screw has provided for the Continental model what Swiftsvertical lever lias clone for the Jackson model; Mr. Baker, ofHolborn, has adopted it and with very satisfactory results ; for ithas passed through that most crucial of tests for a line adjustment,its employment in photo-micrography, with excellent results ; and 166 THE HISTKY AND DEVELOPMENT OF T
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
