LIST OF ILLUSTRATIONS 



Page 

 Figure 1, Production of Coal in Various Countries 17 



Figure 2, Relative Value of U. S. Mineral Products 18 



Figure 3, Map of Petroleum and Gas Fields in U. S 23 



Figure 4, Average Yearly Production of Coal in U. S 24 



Figure 5, Annual Production of Petroleum 1859 to 1910 25 



Figure 6, Map of Coal Fields in U. S 26 



Figure 7, Reaction of a Small Micropterus Dolomieu to Tem- 

 perature 56 



Figure 8, Hydropsyche or Rapids Community 79 



Figure 9, Sand, Gravel or Pool Community 80 



Figure 10, Number of Observations on Weather Elements 85 



Figure 11, Barometric Pressure 86 



Figure 12, Wind Direction 87 



Figure 13, Wind Velocity 88 



Figure 14, Wind Velocity 89 



Figure 15, Temperature 90 



Figure 16, Vapor Pressure 91 



Figure 17, Relative Humidity 9 2 



Figure 18, Amount of Cloudiness 93 



Fguire 19, Frequency of Precipitation 94 



