14 



HARDWICKE'S SCIENCE-GOSSIP. 



Fig. 10. Tamarisk (Tamarix gallica). 



C. densus and C. paradoxus, Rhabdoweissa Jugax, &c. 

 Asplenium viridc is found in ascending Cader, and 



MICROSCOPY, 



An easily-made Cell. — The " American Journal 

 ol Microscopy " gives the following excellent recipe 

 for constructing cells: — "A cell which we have 

 found very durable, easily and quickly made, and 

 very neat, is constructed as follows : Having pro- 

 cured some good gold size and pure litharge, grind 

 the latter to a very fine powder. Mix the litharge 

 and gold size to the thickness of cream, and colour 

 either black or dark olive by adding lamp-black. 

 With this paint, as it may be called, make as many 

 cells as are wanted, and when made, dust finely- 

 powdered litharge over them until they are covered 

 a sixteenth of an inch deep ; allow them to stand a 

 few minutes, and then shake off all the loose litharge 

 by means of a few smart taps. The surface of the 



Fig. ii. Ladies' Tresses Orchid {Spirant 'ies aiitumnalis). 



Lastrca amithtm grows in woods near Penman Pool. 

 — J. Percraal. 



cell will now be quite rough. Allow it to stand a 

 few hours, and then press it against a plate of glass. 

 If this be done carefully, a smooth, solid ring will 

 be left on the slide. If the edges should not be as 

 smooth as they ought to be, it is easy to trim them 

 off on the turntable by means of a small chisel. 

 Such cells, after a few weeks, become very hard, and 

 may be finished so as to be very neat. For dry 

 objects they leave nothing to be desired, and as we 

 have had them in use for over five years, we can 

 speak as to their durability. For objects mounted 

 in liquids it will be necessary to coat them with 

 suitable varnish. Thus, for saline liquids, a coating 

 of gold size renders them perfectly impervious. For 

 glycerine use Bell's cement, or a solution of shellac in 

 alcohol." 



