DUST AND ITS DANGERS. 



CHAPTER I. 



THE NATURE OF DUST IN GENERAL. 



IF this were not a practical age, and if the 

 title on the back of this little book did not 

 fairly promise a reasonably practical theme, it 

 might be thought incumbent on the writer, 

 in this age of nice analysis of very small things, 

 to be explicit at the outset as to what he does 

 or does not mean when he says dust. For af- 

 ter all, when we think of it, there are a good 

 many kinds of dust. There is, for example, 

 molecular dust, which swaying ever in space 

 catches and breaks the sunbeams, giving us 

 now the deep blue of full day and again the 

 gorgeous colors of the earlier and later hours. 



