2 TOWERS AND TANKS FOR WATER-WORKS. 



In scope such works were necessarily limited by topograph- 

 ical conditions, and permitted only the application of the 

 principles governing what is to-day known as "The Gravity 

 System." 



For centuries this method of water-distribution prevailed, 

 varied and modified to suit different conditions, but being 

 shorn from time to time of original crudities, and participating 

 in the general advance toward a higher civilization, the system 

 has reached a high degree of efficiency. 



The wonderful advancement of the present epoch in scien- 

 tific knowledge and mechanical development has made possible 

 the economical production and transmission of power, along 

 with which has come the knowledge of, necessity for, and ad- 

 vantage to be derived from the employment of mechanical 

 means and methods for the accomplishment of required results 

 by other than the primitive principles of gravity flow. 



The reference to advantages to be derived from the em- 

 ployment of artificial methods as applied to water-distribution, 

 rather than the utilization of natural agencies, is relative, and 

 is intended to apply only to a broadening of the possibilities; 

 for in the consideration of the question of general or particu- 

 lar source of water-supply, the first investigation should deal 

 with the possibility of procuring a gravity flow, and all sub- 

 sequent propositions should be referred to the cardinal princi- 

 ple and initial hypothesis that for economy, efficiency, and 

 consequent desirability, Nature's methods take precedence 

 over mechanical means. 



Methods of Distribution. Since the application of scien- 

 tific methods to natural forces, the problem of water-distribu- 

 tion may be broadly separated into three general schemes or 

 systems "The Gravity," "The Reservoir," and "The Di- 

 rect"- each showing particular advantage in individual cases. 



Of the first of these, for the purposes of this discussion, 

 possibly enough has been said. 



