196 HIDDEN BEAUTIES OF NATURE 



through a layer of warm air it arrives on the earth as 

 sleet. As snow is one-tenth the weight of an equal 

 bulk of rain, it follows that a fall of snow ten inches 

 deep will be equivalent to a fall of rain one inch 

 deep. The loose texture of snow renders it an 

 extremely bad conductor of heat, hence a fall of 

 snow thus acts like a mantle of fur thrown over 

 the earth.' 



Dr. Maddox, the skilful microscopist, is credited 

 with the following experiment : 



It is said that he breathed on the window-pane in 

 his room during frosty weather, then bringing his 

 microscope towards the pane he carefully focussed 

 the objective, and looking through, he saw that a 

 number of curious crystals were formed. Possibly 

 the chemical contents of the breath along with the 

 moisture took on definite shapes, as is the case in 

 most mineral substances. He is then said to have 

 attached his camera to the microscope, and to have 

 taken a photograph through the microscope. A copy 

 of that photograph, which I purchased some years 

 ago at How's, in Farringdon Street, forms fig. 53. 

 This must not be mistaken for a direct photograph of 

 a considerable portion of the surface of the pane of 

 glass, for, at the time, I was led to understand the 

 space photographed was about the tenth of an inch 

 in diameter. 



If this be so, and I have no doubt about it, we have 

 a wonderful collection of crystals, each different 

 pattern representing some special chemical substance, 



