EECREATIVE SCIENCE. 



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tliem to the paper, aad prevents their being 

 rubbed off. 



I use three ounces of corrosive sublimate 

 at the time (sufficient to poison a little mul- 

 titude), and have always several preparations 

 in hand ; but I should advise amateurs not to 

 manufacture for themselves, as poisons are 

 dangerous tools to play with. 



MOUNTING. 



The larger species must be glued on paper 

 the size of the herbarium. For this purpose 

 the best transparent glue must be obtained, 

 broken and soaked in cold water two days 

 before using. There can be no rule with 

 such an extensive and variable order as 

 this, but in some cases oil, in others mutton 

 fat, and in others lime-water must be mixed 



with the glue. For the smaller a solution of 

 gum acacia should be used, with a little 

 whiting and moist sugar, and four drops to 

 the pint of oil of cinnamon. The most 

 delicate may be floated on paper from gum- 

 water, and when dry by exposure to the air, 

 lightly coated with varnish; the same process 

 as used for seaweeds will be useful for many 

 fungi. Leaf fungi will form good practice 

 and good objects for drawing or tracing, 

 mounted between two sheets of glass ; the 

 smaller species should be mounted on small 

 pieces of paper, and pinned on the herbarium 

 paper, they can then be removed from time 

 to time, as others are added. Both sides of 

 the fungus shoidd be shown when pos- 

 sible. 



Feedeeick. y. Beocas. 



DIATOMS: 



HOW TO EXAMINE AND PEEPAEE FOE THE MICEOSCOPE. 



Having obtained, as supposed in our last, 

 the materials for examination in a satisfactory 

 condition for working with, let a little of the 

 brown jelly-like substance be taken up on the 

 point of a pen-knife, and placed on a slip of 

 glass, three inches by one, called a slide ; 

 over this put a piece of thin covering- glass, 

 and, if necessary, add a drop or two of the 

 water from which our objects were taken. A 

 very small portion will suffice, for the power 

 to be employed makes it seem two or three 

 hundred times as much as it really is. In such 

 an examination as this, use for the ordinary 

 slide a larger one, with a slip cemented at 

 the bottom, called a glass "table ;" this will 

 prevent water running down on to the frame 

 of the microscope, which would, particularly 

 if it contain salt, quickly injure it. • 



If now we have got hold of naviculge or 

 their allies, a very curious sight will be pre- 

 sented, the whole of the objects in the field 



of view being endowed with active life and 

 moving about in different directions. This 

 motion is well calculated to arrest atten- 

 tion ; it is not the rapid meteor-like whirl of 

 most of the infusorial animalcules, but a 

 gentle gliding in one direction, the distance 

 and the time occupied in traversing it being 

 clearly defined and readily noted by a good 

 watch ; there is then a brief period of rest, 

 and the return journey is duly proceeded 

 with. Should two meet in their paths, they 

 may either glide past one another, or, after 

 being stopped in their forward course for an 

 interval, they will set off back again ; so also 

 if it be a fragment of stone by which they are 

 arrested. That the force with which they 

 move is considerable will be readily seen by 

 the vigorous way in which bits of stone, etc., 

 will be pushed aside. Calculations of the 

 rate of speed in different species have been 

 made, to the effect that the most rapid will 



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