96 BULLETIN 852, TJ. S. DEPARTMENT OF AGRICULTURE. 



first called to the matter about 10 years ago, when it was discovered 

 that a film of bicarbonate of lime had been deposited on the interior 

 of the 36-inch concrete pipe line (No. 53, experiment FF 3) referred to 

 in the author's treatise. 



The writer then made an examination of the steel and iron pipes in 

 the domestic water system at Rialto, carrying the same kind of water, 

 and found these pipes coated in the same manner as the concrete pipe, 

 the thickness of the accretion depending upon the length of time dur- 

 ing which the pipe had been in service. 



Some of these iron and steel pipes had been laid since the year 1885, 

 and during the 20 years of their use had accumulated from one-fourth 

 to three-eighths of an inch coating on the inside. After that two ex- 



gerimental steel pipes were installed for observing the effect of water. 

 >ne of these was placed in position in the month of November, and 

 when observed again the following April there was very little evidence 

 of any deposit. At the same time, another pipe section was installed 

 new, just below the one which had been in use from November to 

 April, and an observation was made on each the following October, 

 which showed that both of them had become thinly coated with a 

 deposit resulting from bicarbonate of lime in the water. As the only 

 difference in the conditions was the temperature of the water, which 

 was cold during the winter and warm during the summer, the con- 

 clusions were that the warmer the water the more rapid would be the 

 deposit in the pipe. 



Another instance of deposit from water carrying bicarbonate of lime 

 in solution on the interior of a steel pipe was observed by the writer in 

 connection with a 36-inch steel siphon carrying the waters from the 

 Southern California Edison Co.'s Lytle Creek power plant from the 

 tailrace of the plant across the canyon to the intake of the Fontana 

 Development Co.'s canal. In 1916 the floods washed out a small 

 section of this pipe, revealing the broken ends of the pipe still in place. 

 On the interior was a deposit of about one-eighth of an inch in thick- 

 ness over the asphaltum coating. 



This pipe line was a steel riveted pipe, dipped in asphaltum accord- 

 ing to the practice in southern California, and was installed new by the 

 writer in the summer of 1904, and had therefore been in use for over a 

 period of 11 years, when it was broken by the floods and observed. 

 The deposit seemed to form over the asphaltum in exactly the same 

 manner as it had been observed to form over the bare steel and iron 

 surfaces in some of the pipes in the Rialto domestio water system. 



The conclusion from all of the above is that deposits from water 

 impregnated with mineral will form on the interior of any kind of a 

 pipe, and that concrete pipes have no greater affinity in attracting 

 such deposits than other classes of pipe. 



' DISCUSSION BY MR. HAZEN. 



The author deserves a great deal of credit for making a large 

 number of useful tests of the f rictional resistance of water in concrete 

 pipes. These pipes are now used to an important extent, and they 

 are sure to find increasing application. There is a great diversity 

 in the methods of making concrete and cement pipes, and it is not 

 surprising to find from the tests that the coefficients vary through a 

 wide range. 



It may be suggested that the coefficients depend to some extent 

 upon the quality of water, and not alone upon the smoothness of 



