. The microscope and its revelations. oscopes which had preceded it was madeby one devised by M. Joblot, and illustratedin fig. 106. The ornamental plate holds thelens, the focus being adjusted by the nut andscrew; the plate next to the ornamental oneis a concentric rotary stage, of good mechanicalquality. The tube A was called by Joblot the Canon, and was lined with black clothor velvet, and has a diaphragm at each diaphragms are movable, which waspractically a considerable optical benefit. In 1738 Dr. IS. LieberkUhn devised,what had been employed in principle byDescartes a century
. The microscope and its revelations. oscopes which had preceded it was madeby one devised by M. Joblot, and illustratedin fig. 106. The ornamental plate holds thelens, the focus being adjusted by the nut andscrew; the plate next to the ornamental oneis a concentric rotary stage, of good mechanicalquality. The tube A was called by Joblot the Canon, and was lined with black clothor velvet, and has a diaphragm at each diaphragms are movable, which waspractically a considerable optical benefit. In 1738 Dr. IS. LieberkUhn devised,what had been employed in principle byDescartes a century before,1 the instrumentthat has ever since been known by his name,and which is still of considerable value to themicroscopist. Fig. 107 is a reproductionfrom the earliest drawing known of Lieber-kiilms microscope. A A is a concave mirrorof silver ; from its form the light is reflected from it to a focus on the object C. The mirror is pierced in thecentre at B, and the lens, or object-glass, is inserted and adjusted. 1 See pp. FIG. 108—Culpeper and Scarlets microscope (1738). 140 THE H1STOKY AND DEVELOPMENT OF THE MICROSCOPE the eve being placed behind in tlie direction D at any point the>iiiide lens or ii coin)ihiatiiin might require. (ulpeper mid Scarlets microscope requires a note, and is illus-trated in tig. His. It was inappropriately designated a reflectinginicroM-ope. but this arose merely from the fact that it was the firstKnuli-li model which employed an illuminating mirror. It was,however, a dioptric, not a catoptric instrument, and is figured inDr. Smiths Opticks, 1738. •A Pocket Reflecting Microscope was figured by BenjaminM;irtin in his Micrographia Xova in 1742, having the interestingfeature of a micrometer eye-piece depending on a screw with a certainnumber of threads to the inch, and by which accurate measurementscould be t;d<en. It was called a reflecting microscope because it hada mirror lilted into its cylindrical base; but it was, in realit
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
