156 THE MICROSCOPE. 



GLEANINGS FROM THE JOURNAL OF THE ROYAL 

 MICROSCOPICAL SOCIETY FOR AUGUST. 



C. H. STOWELL. 



Organic particles in the air of mountains. — The air of moun- 

 tains always contains germs although in different proportion to that 

 of the plain. 



The currents of air are constantly giving a circular shape to the 

 particles suspended in it, and that such particles can then be raised 

 to great heights. Insects play a certain part in this circulation. 

 The essential composition of the air itself appears to be the same at 

 all heights. 



The withering of flowers and leafy shoots. — Cut flowers wither 

 less rapidly when there are no leaves attached to the shoots, and if 

 transpiration is prevented from the leaves the flowers remain quite 

 fresh. 



Leaves absorb more water as a rule through the under than 

 through the upper surface; rain and dew, therefore, do not usually 

 supply much water directly to the plant. 



Depth of vision in photo-micrography. — The conclusion Mr. Davis 

 reaches is that large objects cannot possibly be penetrated even with 

 objectives of low angle and medium power, for what is seen through 

 the microscope is the result of the combined effects of the accomo- 

 dation of the eye and the focal depth of the objective, and when a 

 picture is thrown upon a sensitive plate the first element is nearly 

 eliminated and the only depth of vision attainable is that which the 

 objective itself possesses. 



Mounting in glycerine. — No cell is used. Just enough glycerine 

 so that it will reach the edge of the cover-glass. Canada balsam in 

 turpentine is then applied round the edge to close the cell. This is 

 done with a glass rod drawn out to a point, but terminating in a 

 little knob. 



[Mrs. Stowell has used this method for a long time and is 



pleased with it. She did not think it a new method, as given above, 



or she could have reported upon it a number of years ago.] 



The Brownian motion. — It is not dependent on the life of the 

 particle. It does not depend on the material of which the particles 

 are composed. The motion does not depend on the form of the 

 particles. It does depend upon or is affected by: The size of the 

 particles, the specific gravity of the particles and the nature of the 

 liquid. 



