226 TEE POPULAR SCIENCE MONTHLY 



Per Cent. 



Bacon 22 



Eggs 65 



Butter 11 to 16 



Richest Milk 87 



Cucumbers 97 



Salmon 75 



Beef 73 



Cabbage 89 



Potatoes 75 



Cheese > 25 to 50 



Strawberries 90 



Apples and Grapes 80 



It would take volumes to tell of all the effects of water as a dynamic 

 agent in geology — of the action of frost, of percolating waters, of rain, 

 of waves, of rivers, glaciers, lakes, oceans, subterranean waters, etc., 

 of all these and more on the exterior and interior of the earth. As 

 justice can not be done to any one of these topics in a few words, they 

 can only be mentioned here. 



The prime importance of water to chemical reactions has already 

 been spoken of above, but in conclusion, one or two examples will help 

 to further show how really essential it is. 



Concentrated sulphuric acid and metallic sodium will react with 

 the most explosive violence if brought together in the presence of only 

 a trace of water, but if proper precautions are taken to exclude every 

 particle of moisture, drying them first and then bringing them together 

 as quickly as possible, there will be no reaction whatever. The fuming 

 of hydrochloric acid and ammonia in the presence of each other is pro- 

 verbial in the chemical laboratory. They combine to form ammonium 

 chloride, which appears in the form of a white cloud. Here again there 

 is no combination, if the two are perfectly dry. Soda and tartaric acid 

 (both solids) can be intimately mixed together, in solid form, without 

 undergoing any reaction. But as soon as water is added, a tremendous 

 effervescence takes place. 



Many other cases might be cited, but these, as well as what has 

 gone before, will, I hope, give some idea, at least, of the all importance 

 of this wonderful yet common substance. 



