850 



ZOOLOGY- 



[Sect. XI. 



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of oceanic luminosity, make it indispensable to include 

 them in directions for collecting facts in natural history. 



Whenever the surface of the sea presents a difference 

 of colour and density, in the form of pellicles, streaks, or 

 shining oil-like ^nots, lift up portions by dipping in thin 

 plates of mica or stout paper, and raising them hori- 

 zontally : dry these and preserve them in s. book, noting 

 the latitude and longitude, the time of day, and the tem- 

 perature of the sea. The animalcules remain attached 

 to the pieces of paper or mica employed in their capture, 



and may be determined by subsequent microscopical 

 observation. 



Where the sea seems pure and colourless a bucketful 

 may be raised and strained through fine linen ; by re- 



peating this act a portion will commonly remain on the 



filter, which is then generally rich in invisible animalcules, 

 and should be preserved in small glass bottles or tubes, 

 with a bubble of air between the cork or stopper and the 

 water, Anv visible o-olaf 



nous 



re 



moved and placed in spirit of wine, or the solution No. L 

 Specim^ens of sea-water thus saturated with animalcules 

 should bo prepared at each degree of latiiade and longi- 

 tude traversed on the voyage, by which means the geo- 

 graphical distribution of these minute organisms may be 

 ascertained, when the species so collected are determined, 

 after the voyage, by microscopic observation. 



bottles or tubes of the water of each mineral 

 spring or hot-spring should be preserved for the same 



In a deposit from melted pancake ice from the 



Barrier, in 78^ 10^ S. lat.. 162' W. loner., brought home 



Anta 



'0-' 



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"/oyage, Ehrenberg detected of sili- 



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