101 



estimates at hand now (from Mr. Henry Birkinbine) give the following 

 for the Schuylkill river in its periods of least annual flow at Philadel- 

 phia: 



1816, there were sent down 500,000,000 gallons daily. 



1825, there were sent down 440.000,000 gallons daily. 



1874, there were sent down 245,000,000 gallons daiiyr 



1875, there were sent down 245,000,000 gallons daily. 

 1878, there were sent down 220,000,000 gallons daily. 

 1881, there were sent down 215,000,000 gallons daily. 

 1895, there were sent down 195,000,000 gallons daily. 



If these figures are correct, as they probably are, it would seem that 

 in 1895 there was available at Philadelphia only 39 per cent, of the 

 water there was in 1816. Or, in other words, that in eighty years 61 

 per cent, of the w r ater that should have been available during autumn 

 in the Schuylkill, at Philadelphia, had disappeared that is, if we as- 

 sume the reported flow of 500,000,000 gallons as a fair average mini- 

 mum flow f or earlier years. 



There is a striking fact in connection with the table just given. It 

 is the progressive decrease, and as if to reinforce the belief in the 

 general accuracy, it will be noted that in 1874 and 1875 the flow is 

 stated roundly at 245,000,000 gallons. It is hardly probable that there 

 will be any dispute over the general statement that we are having less 

 flowing water available at the critical season of the year than form- 

 erly. How it is to be accounted for is quite another question. Three 

 explanations might be, or are, offered : 



1st. That we are passing through a period of less rainfall than form- 

 erly. 



2d. That the disastrous change is due to disturbing the former bal- 

 ance of natural conditions by removal of the forests. 



3d. That much of this missing water has been used before it reaches 

 the point or points at which the estimates were made. 



Taking the last of these explanations first, it may be briefly stated 

 that it does not seem possible, or even probable, that the deficiency of 

 flow can be caused by use of water, because, in the first place, the 

 diminished) flow is often as marked at the head of the streams, and 

 above any point of use, as it is below. In the second place, very much 

 of what is used is not carried out of the country by the users^and must 

 again find its way into the soil, or stream, at, or near, the point of use. 

 In the third place, for that which is carried off by locomotives, either 

 as water or as vapor, almost as large a portion is returned in the one 

 form or the other to the region from some other points. It would be 

 very interesting to learn the exact quantity of water consumed by our 

 railroads. 



Of the two remaining explanations that which seems least appli- 

 cable to existing conditions of water flow is the one which assumes a 



