. The microscope and its revelations. rlytouches the crystal; then focus with the draw-tube exclusively. Thesuit-stage condenser should be racked up close to the under side ofthe crystal. The use of monochromatic light is frequently desirable in micro-scopic work, especially blue light, although of less moment thanin p re-achromatic days. The usual method of obtaining colouredlight is to pass sunlight through coloured glass, or through acoloured solution, such as the ammonio-sulphate of copper ; but thisis a most imperfect and unsatisfactory method, and does not givemonochromatic light. This m
. The microscope and its revelations. rlytouches the crystal; then focus with the draw-tube exclusively. Thesuit-stage condenser should be racked up close to the under side ofthe crystal. The use of monochromatic light is frequently desirable in micro-scopic work, especially blue light, although of less moment thanin p re-achromatic days. The usual method of obtaining colouredlight is to pass sunlight through coloured glass, or through acoloured solution, such as the ammonio-sulphate of copper ; but thisis a most imperfect and unsatisfactory method, and does not givemonochromatic light. This most valuable mode of illumination hasbeen made possible by the use of what is now known as the Gifford screen, from the name of itsinventor, Mr. J. \V. (Jittnrd ;and when artificial light isused one of these screensshould be interposed betweenthe lamp and the sub-stagecondenser. It is shown in , and consists of a glasstrough, about 3 inches long by2 inches broad and y^ths deep,filled with a solution of methyland glycerin mixed.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
