12 BULLETIN 155, U. S. DEPARTMENT OF AGRICULTURE. 
more than that of the thin metal clips, but it is claimed that the 
difference in cost is more than offset by the time saved in building ~ 
the pipe and by eliminating expense of saw kerfs. _ 
For the ordinary clips No. 12 gauge steel or wrought iron is — 
used. As a rule they are 1$ inches wide and the length is one- 
eighth inch greater than that of the saw kerf, so as to allow the ends 
to project one-sixteenth inch at each edge of the stave. 
PROTECTIVE COATING OF BANDS. 
The bands of continuous stave pipe are nearly always dipped or 
painted with some form of protective coating, and sometimes the 
shoes also. For this purpose there are numerous patented or trade 
preparations on the market, some one of which may be specified. 
They consist usually of asphaltum in combination with linseed oil 
or other ingredients for tempering and reducing, and, as a rule, are 
to be applied hot. Some manufacturers, however, are coming to 
recommend a cold dip instead of the hot, believing it to be equally 
effective. | 
INTAKES AND OUTLETS OF PIPE LINES. 
The design of the intake and outlet of every pipe line must be a 
matter depending upon local conditions and character of service for 
which the pipe is intended. For this reason standard designs can 
not have a wide range of adaptability, but some points that usually 
require consideration in designing such structures for service of 
whatever nature are common enough to merit brief discussion.. 
The material used for intakes and outlets is usually either wood, 
concrete, or masonry. Wood has been used extensively and in first 
cost is usually cheaper than other materials. Its life is comparatively 
short, and if economic conditions will permit, something more dura- 
ble should be employed. In connection with power developments, 
wells of cribwork have often been used to give the desired entrance 
head, and the same kind of construction is sometimes employed at 
outlets also. Examples of wood and concrete intakes are shown in 
Plate II. Figure 1 shows the intake to the pipe of the Logan(Utah) 
City Power Co. and figure 2 the intake of the pipe line of the 
Kings Hill irrigation project crossing the Snake River near Bliss, 
Idaho. 
The plans of a wooden intake and an outlet box, fairly typical of 
this class of irrigation structures, are shown in a previous bulletin.’ 
These were built in 1894, and after nine years of satisfactory service 
were still in use, though to some extent decayed. Lumber at the time 
these were built cost $15 per thousand delivered along the canal. 
1U., S. Dept. Agr., Office Expt. Stas, Bul. 131, p. 49, 


