346 



Marvels of the Universe 



Fhoto bi'] [<;. I'arkiji. 



ICE CR">STALS. 



These Crystals forming in water are the first 



stage in the production of solid ice. 



It has been said that foliage-forms assumed by hoar- 

 frost are the result of the markings of the surface on 

 which it is deposited. To a very small extent these 

 may have some effect, but they do not account for the 

 beautifully-curved lines and mimic forms of plant-life dis- 

 played bv hoar-frost. The window-pane designs are but 

 another variety of hoar-frost, and as the glass is smooth 

 and completely devoid of any guiding lines, their forms 

 must depend upon some other cause. 



Most of the curved patterns on the window-pane can 

 be accounted for by the currents of air charged with 

 moisture in the room. These currents can be detected 

 by smouldering paper or any such light combustible. 

 The air is never still or motionless unless all the air in 

 the room is of one temperature. 



Cold, the absence of heat, is one of the chief agents 

 in the condensation of vapour which the atmosphere 

 always holds in larger or smaller quantities, whether in a 

 warm room or out of doors. 



When a current of air passes over stretches of water or 

 the damp surface of the earth it becomes charged with moisture, and as it is only capable of 

 retaining a certain quantity, much less when cold than when warm, it follows that warm air, 

 when so saturated, must surrender some of its moisture on cooling. The moisture thus liberated 

 is deposited as snow, rain, or hoar-frost. This enables us to see what takes place in a warm 

 room during a frosty night. The currents of air passing along in curves part with their fog-like 



particles of water, which are frozen into some of the 

 various forms already referred to. 



So far we have said but little about the chief agent 

 in the formation of frost-figures. Water holds the pre- 

 eminent place among all the substances so extensively 

 used in the operations of Nature on our globe. It is 

 composed of invisible gases. It is almost colourless ; 

 it is brilliant, without taste in its pure state ; it has 

 no smell, and it is transparent. It assumes the gaseous, 

 liquid or solid states with great facility. It is the largest 

 ingredient in the composition of animals and plants, and 

 it forms an important part in several rocks of the globe. 



It is not generally known that the crystals and 

 window-pane frost-forms have the power of reproducing 

 lost parts. Paget, in his work on " Pathology," shows 

 that crystals, as well as certain animals, possess the 

 remarkable power of repairing their own injuries. His 

 statement is as follows : " The ability to repair damages 

 sustained by injury is not an exclusive property of living 

 beings, for even crystals will repair themselves when, after 

 pieces have been broken from them, they are placed 

 in the same conditions in which they were first formed." 



Beauty of form and of colour are both embodied in 

 the window-pane frost-foliage, but the colour is only 



Photo by'\ 



ICE CRYSTALS. 



[(/. farkui. 



Another group of the simple, first stages in the 

 formation of ice on water The Crystals are seen 

 to be long, thin and spear-like. 



