94: SCIENCE OF COMMON THINGS. 



Red and green snow. "What is hail ? Meteorites. 



GO4 Does snow ever occur of any other appearance than white? 



Yes ; in the Arctic regions and on some mountains 

 it is red, and occasionally green. 



6O5 What is the cause of these appearances 1 



These singular hues are occasioned by little micro- 

 scopic plants, which germinate and live in the snow. 

 They consist of little globules from TT f To - of an inch to 

 3-500 f an inch. Each globule is divided into seven 

 or eight cells filled with a liquid, which gives a color 

 to the snow, and is sometimes green and sometimes red. 



eoe What is 'hail? 



Rain, which has passed in its descent through some 

 cold bed of air, and has been frozen into drops of ice. 



GOT* What makes one bed of air colder than another f 



It is frequently caused by electricity unequally dis- 

 tributed in the air. 



60S How can electricity make air cold ? 



Air, when electrified, is expanded, and expansion 

 produces cold. 



6O9 Why does hail fall generally in summer and autumn f 



Because the air is more highly electrified in summer 

 and autumn than in winter and- spring; and the vapors 

 in summer and autumn (being rarefied) ascend to more 

 elevated regions, which are colder than those nearer 

 the earth. 



G1O Is the occurrence and formation of hail clearly understood? 



It is not ; much information exists upon the subject, 

 but no theory has yet been formed which satisfactorily 

 accounts for all the facts which have been observed. 



Gil What are meteorites f 



Meteorites are solid, luminous bodies, which from 

 time to time visit the earth, moving with immense 

 velocity, and remaining visible but for a few moments. 

 They are generally accompanied by a luminous train, 

 and during their progress explosions are often heard. 



61Q What is an aerolite f 



The term aerolite is given to those stony masses of 



