1992 



Journal of Applied Microscopy 



side of the wooden base. The aperture in 

 the glass top through which the draw-tube 

 emerges is lined with felt in such a way as 

 to be dust-proof. 



The microscope is kept in fixed focus 

 with the aid of a clamping ring at the upper 

 end of the body-tube. The ocular also is 

 fastened by a set-screw. In order to avoid 

 the possibility of forcing the whole micro- 

 scope-body downward by heavy pressure 

 from above, to the detriment of the exhibi- 

 tion object, an accurately fitting block of 

 brass is now slipped in between the trans- 

 verse arm and the movable support below. 

 With these precautions, the lenses remain 

 in focus and the chance of accident to the 

 exhibition object is practically removed. 

 Most of the instruments are fitted with 

 ocular II and objective 8, giving a mag- 

 nification of about 70 diameters. 



The objects selected for display at 

 the present time are chosen from among 

 the lower plants and help to illustrate the exhibits in the neighboring show-cases 

 of the systematic museurn. Each microscope is accompanied by a label bearing 

 a moderately detailed explanation of the object exhibited. The preparations on 

 exhibition at the date of writing are as follows : 1. Plasmodium of a slime-mould 

 {Physarum cinereuni) — stained ; '1. Spore-bearing stage of a slime-mould (Dictyd- 

 ium iimbilicatum) — dry mount ; 3. A diatom {Isthfuia nervosa) ; 4. A green 

 fresh-water alga {^D raparnaldia) ; 5. A green seaweed {Anaiiyomene stcllatd) ; 

 6. A hroviw s&2i'^eed {Ectocarptis si/iculosus) ; 7. A red fresh-water alga (^a/'ra^Ty^- 

 ospermuni) ; 8. A red seaweed {Pti/ota elegans) : 0. A red seaweed {Polysiphonici) ; 

 10. A red seaweed {Ccraniiiifn) ; 11. Spores of the rose-rust {Phragmidium sub- 

 corticium) ; 12. A saprophytic fungus {Sporormia herculed) ; 13. A saprophytic 

 fungus {Ascobolus) : 14. A saprophytic fungus (^Sarcoboliis^ ; 15. Section of a 

 lichen {Soloriiia croced) ; 16. A scale-moss or leafy liverwort {Frullatiia N'isqual- 

 lensis) ; 17. Spore-case of a leafy liverwort {Frullania Bolanderi) ; 18. Cross- 

 section of a moss-leaf Polytrichnm commune) ; 19. Spore-case and peristome of a 

 moss (Punaruz hygrometricd) — dry mount; 20. Lid and ring of a moss-capsule 

 {Funaria hygrometrica) : 21. V &r\s\.ome. oi2i moss {Afnium ciispida turn) ; 22. Cross- 

 section of the leaf-stalk of a fern i^PoIypodium vulgare) ; 24. Spores of a horse- 

 tail {Eqiiiseium syhurtiaim). Marshall A. Howe. 

 New York Botanical Garden. 



Fig. 2. — Exhibition Microscopes mounted 

 on table. Heavy iron sills in the bases 

 of the tables secure the necessary 

 stability. 



