182 FIRESIDE SCIENCE. 



found in the tobacco plant, and although the spec- 

 troscope will detect in any substance a quantity so 

 infinitesimally small as the six millionth part of a 

 grain, yet it is hardly revealed in soils in which the 

 plant flourishes. These facts open up subjects of 

 thought so interesting and instructive that it is 

 hazardous to enter upon their consideration in the 

 limits of a brief essay. I have only drawn a mere 

 outline of some of the important relations of water 

 to agriculture. It is a subject of almost limitless 

 extent, and may be studied with profit by every 

 cultivator of the soil. 



Before closing may I be permitted to ask and 

 to answer the question, What is water ? I suppose 

 some of my readers are ready to make the Dog- 

 berry-like reply, " Water, sir, is water." That 

 certainly reaches the point by a very short cut, but 

 to the thinking, inquiring man it is not quite satis- 

 factory. Let us answer the question from the 

 standpoint of the chemist. Water is rust. The 

 red powder that falls from iron which has long 

 been subjected to the action of moisture is rust of 

 iron. It is the oxide of a metal, and so is water. 

 Water is the rust of hydrogenium, a true metal. 

 This wonderful element no human eyes have ever 

 looked upon, and probably never will, as in its 

 free state it exists only in the form of an invis- 

 ible gas. Quite recently, science has demonstrated 



