96 BULLETIN 852, U. 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- 
perimental steel pipes were installed for observing the effect of water. 
One 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 domestic 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 
