No. 6. DEPARTMENT OF AGRICULTURE. 541 



I saw enough of the deposits in Arizona and Senora to persuade me 

 to believe, or at least hope, that Arizona would ultimately yield 

 her proportion 9f the carboniferous products in the shape and quality 

 of good coal of several kinds to place her in the list of the coal pro- 

 ducing states. Within the last three years, or about eighteen years 

 after my hurried exploration down there, tbe assistants of the United 

 States Survey secured some accurate information and reliable figures, 

 whereupon they have announced, with the approval of the Director, 

 that Arizona contains as much available coal as the entire amount 

 thus far mined and used in the whole country, and, of course, this 

 Qieans many billion tons. 



Thus, while the actual epochs or periods in which coal may ''exist" 

 have been ascertained to a certainty and geologists have proved the 

 limit of the rocks that contain coal, yet the defective estimates of 

 acreage and extent is due to the superficial and hurried manner in 

 which the coal fields are in the first instance examined; and, there- 

 by, the actual extent of the coal bearing rocks not demonstrated 

 or determined in a given field, locality or state; and, as a result, 

 the maps and reports very much circumscribe the coal basins, and 

 exclude from the estimates and surveys much of their area that 

 otherwise and by careful investigation would be contained in the 

 figures that report the same. 



In after years, a revision of these reports and a more careful and 

 thorough development show a very marked increase from the original 

 figures and estimates, both of quantity and area. This applies to 

 every state that contains coal, and in which the tendency to submit 

 a conservative report has so often warped the judgment and furnished 

 a minimum computation with reference thereto. 



Thus, in my report to you two years ago, I estimated from ninety 

 to one hundred billion tons of coal in this State; so that my prior 

 figures in a venture to estimate the amount in the United States as- 

 sumed that our State contains about one-thirty-fifth of the entire 

 quantity of coal in the United States. The length of time that this 

 amount would supply the people, (varying figures having been sug- 

 gested by prominent geologists,) depends, of course, upon the increas- 

 ing demand, the economical and careful mining, with the probable dis- 

 covery of devices or methods whereby the coal waste will be reduced 

 to a minimum, its by-products utilized and the entire body of heat 

 produced be controlled and husbanded with the least possible loss. 



Again, what skill and invention may do to provide for some of the 

 needs now depending on coal and thereby reducing the demand, or 

 at least restraining the demand, no one can conjecture; and that it 

 may be many centuries, perhaps some thousands of years may elapse, 

 before the Kation shall experience a coal famine; and what may be 

 provided as a part substitute for coal ere such a calamity may ensue, 

 no one can venture to surmise, "for the thoughts of men are widened 

 with the process of the suns." Genius is limitless in its concep- 

 tions and possibilities towards contrivance and invention. Another 

 feature of the utility of coal and its value to the consumer is that 

 while analysis will determine exactly its elements and its amount 

 of combustible matter, yet its chemical composition does not alwnys 

 indicate the real or comparative fuel efficiency which ofttimes seeans 



