THE MICROSCOPE. 18? 



179. Are the prices quoted in the advertisement of Watson & Sons, 

 in the Microscope, the prices in the United States duty paid? — G. H. G. 



No. They are the prices in London, the purchaser to pay 

 freight and duty. 



180. I have a \ inch objective and desire a higher power for the 

 study of vegetable histology. Would a 1-7 inch, or i inch, dry objec- 

 tive, student grade, serve the purpose t My time for microscopic work 

 is limited. Would 1 be able to get satisfaction from an immersion 

 lens, working one or two hours daily ? — G. H. C. 



A low angle, dry 1-7 inch, or i inch objective would not be 

 satisfactory in practice. A $■ inch, or i inch, immersion lens 

 will give cleaner and brighter images and is to be preferred. 

 Get an oil immersion objective. It will have a good working 

 distance, and respond to a comparatively small movement of 

 the collar. Such an objective is easier to master thau a water 

 immersion lens, and will give much better satisfaction in actual 

 work. 



PRACTICAL SUGGESTIONS. 



By L. A. WILLSON, 



CLEVELAND, OHIO. 



An Evening With Mosses. — The other evening a scien- 

 tific friend called to have me show him some mosses with my 

 'scope. He had twenty-five or thirty different species that he 

 had gathered, named, and mounted. The mounting was quite 

 unique. Spreading the plant without any mounting medium 

 upon a glass slip, taking pains that all parts should be displayed, 

 he covered with thin glass or mica and fastened the covers by 

 pasting strips of paper at their margins. On these slips he wrote 

 their generic and specific names. The specimens looked ele- 

 gant either as opaque or as transparent objects. 



Mounting of Mosses. — The method above described is a 

 quick way but requires a great deal of patience to get the leaves 

 spread out and the fructification displayed. As the tissue is a 

 light cellular tissue with no vascular parts, I find that balsam, 

 especially benzole balsam, is a suitable medium. To mount, 

 use a shallow cell. Tease and soak the specimen well in alco- 



