Fig. 95. Fig. 96. 



ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 551 



may be used by an intelligent child, as well as by tbe experienced 

 microscopist. It was termed a ' Field Naturalist ' rather than a 

 ' Dissecting ' Microscope to disarm the suspicion with which some 

 people look upon an instrument with the latter name as a rack or 

 means of torture for frogs, &c." 



The woodcuts render any detailed description of the instrument 

 unnecessary, and we need only call attention to the sloping rest for 

 the hands and that there are three lenses, a condensing lens, forceps, 

 and live-box. The lenses drop into the arm which carries them, and 

 also into each other, so that they may be used in combination, 

 producing seven powers in all. 



Marshall's turntable can also be used with the instrument, the 

 spindle passing through a hole in front 

 of the stage, and its point revolving in 

 a brass socket below. 



Steinheil's Achromatic Eye-pieces. — 



These eye-pieces (| in. and ^ in.), exhibited 



and described by Mr. Ingpen at the June 



meeting of the Society, are shown in 



Figs. £5 and 96 in section. They are 



especially adapted for micrometry. They consist of a double convex 



lens of crown between two meniscus lenses of flint, all cemented 



together. Grooves cut in the edge and blackened, form diaphragms 



as in the Coddington lens. 



New Combination for Objectives.* — The following is the whole 

 of the note by C. V. Zenger under this heading published in the 

 ' Comptes Eendus ' : — 



" The author proposes to obtain an amplification equal to 2000 

 with a large focal distance. It would then be possible for anatomists 

 and physiologists to carry on their dissections and preparations with 

 a very considerable amplification, at a distance from the objective equal 

 to 4 mm. or 6 mm." 



Fluid for Homogeneous Immersion.']' — Professor Abbe finds that 

 pure cedar-oil may be prepared so as to render it much less fluid than 

 in its ordinary condition. By spreading it out in thin layers and 

 exposing it for a long time to the influence of air and light, it becomes 

 of the consistency of castor-oil, and without any increase in dispersive 

 power, its refractive index is raised to 1" 518-1 -520. If desired, 

 the index can of course be reduced to 1-510 by the addition of olive 

 or castor oil. 



Dr. L. Dippel considers that this fluid unites in itself all the 

 properties required for such a fluid, and that it makes all others 

 superfluous. 



Shurley's Improved Slide for the Examination of Gaseous 

 Matter.^ — Dr. E. L. Shurley describes an apparatus for the examina- 



* Comptes Eendus, xciv. (1882) p. 1542. 



t Bot. Centralbl., x. (1882) pp. 224-5. 



X Proc. Amer. Soc. Micr., 4th Ann. Meeting, 1881, pp. 65-8 (1 fig-). 



