ANCIENT AND MODERN WORKS. 120 



divided into six panels, was proportioned to sustain the combined 

 load due to the weight of the water, the metal of the structure, 

 and the assumed wind pressure and resulting stresses. Stresses 

 were not to exceed 14,000 Ibs. per square inch for members not 

 exceeding 90 times their least radius of gyration between supports 

 and for greater lengths the allowable unit stress was to equal 

 20,000 Ibs. 70 times the length in feet divided by the least 

 radius of gyration of the section in inches. No main post was 

 to exceed 100 times its least radius of gyration and no other 

 strut 150 times the radius. 



Columns were secured to steel base plates, reinforced with 

 angle connections designed to resist vertical shear stresses not 

 exceeding 10,000 Ibs. per square inch. The bearing value of 

 the base plate was such that no more than 400 Ibs. pressure was 

 exerted upon the cap-stone, transferring not to exceed 100 Ibs. 

 per square inch upon the masonry piers supporting the columns. 

 The sub-foundations were proportioned so that the bearing upon 

 the natural soil was not greater than two tons per square foot. 

 The overturning moment of the water tower was calculated from 

 the assumed wind pressure resisted by the weight of the structure 

 when empty. 



The work in the shop corresponded to usual good practice. 

 Plates exceeding three-eighths (f) of an inch were beveled by 

 machine; other plates were sheared. 



For rivet holes, plates under five-eighths (f) of an inch were 

 punched. Those from five-eighths (f) to seven-eighths (J) of an 

 inch were reamed, and plates exceeding that thickness were 

 drilled from the solid metal. 



In general all bends were to be made cold. Plates less than 

 seven-eighths (J) inch were connected by lap-joints; all others 

 were of the butt- strap type. 



The inside of the tank was painted with an " ice machine 

 enamel," while two (2) coats of graphite was used for the exterior 

 surfaces. 



This tank had a capacity of some 150,000 gallons and the 



