152 W. & L. E. GURLEY, TROY, NEW YORK 



rnu-t he changed at least every seven days, but is of sufficient 

 length to allow some variation in the exact time of making the 

 change. 



Tin* graphic record shows at a glance the stage ami lime 

 relation**, and is easily interpreted. It is adapted to any 

 graphic method of calculation. The range of stage, which is 

 unlimited, is adjusted to particular needs by the use of proper 

 gear combinations to give an appropriate scale ratio for stage. 

 'I'h:- time scale is ordinarily one inch per hour, hut lime screws 

 can be furnished to give a one day, or four day, time scale. 



Accurate in I urination in regard to the water stage in both 

 forebay and tailrace at all water power stations is necessary. 

 At such stations Gurley Graphic Registers afford a method of 

 obtaining and recording the required information in convenient 

 form. Provision should be made in designing the power plant 

 and its accessories for the proper installation (See page 140) 

 of water stage registers. 



Such records frequently prevent disputes and often assume 

 great importance in legal actions concerning the use of the 

 water. 



The successful operation of sewage disposal works requires 

 an accurate knowledge of the quantity of sewage to be treated. 

 Such knowledge may readily be obtained by the use of Gurley 

 Graphic Registers properly installed. The quantity of effluent 

 discharged and its degree of dilution may also be determined 

 by such use. See page 142. 



The quantity of sewage flowing in trunk sewers or in inter- 

 cepting sewers may be readily determined by the use of Gurley 

 Water Stage Registers. This information is essential to and 

 should precede the design of sewage disposal works. 



A record of the height of water in reservoirs, and its 

 fluctuation, is easily obtainable by the use of such registers. 

 This is desirable in all reservoirs of any domestic water supply 

 system. Such records aid in the successful operation of the 

 systems. The head and its fluctuations are very important 

 elements of efficient operation where water is pumped into 

 distributing reservoirs. In such situations records are 



