22 TOWERS AND TANKS FOR WATER-WORKS. 



was estimated to have withdrawn the water some 20 feet below 

 the top of the tank. 



The accident was preceded by a crashing sound due to 

 falling ice, followed by a loud, rending report and the rush of 

 water and ice on the east side, and ending in a rumbling sound 

 as the main upper section, containing several hundred tons of ice, 

 struck the ground. About one-fifth of the plates, consisting of 

 most of the four lower rings, were torn loose from the upper section 

 and from the bed-plate, and were projected by the reaction of the 

 escaping water to the southeast of the foundation, while the 

 upper 75 feet toppled to the east or northeast, falling vertically 

 to the foundations, and landing, a flattened mass, in a north- 

 easterly direction and free from the foundation. An examination 

 of the ruins indicated that the initial rupture occurred on the 

 east or northeast side, about four courses from the base. The 

 holding-down bolts, twenty-two in number, failed mostly in the eye. 



Twice each year since the stand-pipe was built it had been 

 emptied and its interior carefully examined. The last inspection 

 was during the previous October, when the stand-pipe was said 

 to have been in satisfactory condition. 



No leaking had been reported for at least ten years, but the 

 pitting action of the water was quite marked, perhaps not more 

 so than is usual elsewhere under like conditions. The interior 

 had been repainted twice since the scand-pipe was built, but 

 very little of the interior paint had survived the first winter owing 

 to the friction of the ice. The mean temperature from December 

 to March for six previous years was 21.8. 



For several days preceding the accident the sun had been 

 shining more or less, and there was doubtless some thawing 

 of the ice in the stand-pipe. 



It turned cold the evening before the failure and a film of 

 ice J inch or more thick formed against the inside of the plates. 



From a study of ice fragments, a great tube of ice commonly 

 formed in exposed stand-pipes against the metal shell had in 



