MAEVELS OF POND-LIFE. 



CHAPTER I. 



PLAIN HINTS ON MICROSCOPES AND THEIR 

 MANAGEMENT. 



Powers that are most serviceable — Estimated by focal length — Length 

 of body of microscope and its eflfects — Popular errors about great 

 magnification — Modes of stating magnified power — Use of an 

 " Erector " — Power of various objectives with different eye-pieces 

 — Examination of surface markings — Methods of illumination — 

 Direct and oblique light — Stage aperture — Dark ground illumina- 

 tion — Mode of softening light — Microscope lamps — Care of the eyes. 



HE microscope is rapidly becoming the com- 

 panion of every intelligent family that can 

 afford its purchase, and, thanks to the skill of 

 our opticians, instruments which can be made to answer 

 the majority of purposes may be purchased for three 

 or four guineas, while even those whose price is counted 

 in shillings are by no means to be despised. The most 

 eminent English makers, Wales, and Toiles, in America, 

 and Hartnack, in Paris, occupy the first rank, while the 

 average productions of respectable houses exhibit so 

 high a degree of excellence as to make comparisons 



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