HEATING BY HOT WATER. 177 
were employed, and not one of them even wept a drop 
at the first trial. 
When fixing a number of lengths of piping, with 
connections, etc., the best way is to lay and roughly level 
them first; then caulk up the joints, which 
brings each into its exact position. Then 
go over them again very carefully with the 
spirit-level, and finally ‘‘make”’ the joints, 
after which they must not be disturbed in 
any way until the cement has set thoroughly. 
Fittings, or connections, such as elbows, 
T-pieces, etc., frequently require to be 
supported in place by means of blocks, etc., 
until the joints are made and the cement is set, when 
the supports may be gently removed. 
Where the currents in two pipes have to be joined 
together and carried in one, what is termed an “outlet 
syphon ’’ (see Fig. 116) is usually employed, or in some 
cases a branch-piece (Fig. 117) is preferable, but if the 
= affluent joins at right angles, an ordinary 
T will be best, naturally. Again, when 
running from a single pipe (say a flow) 
into ¢wo others (as returns), if these are 
placed one over the other, branch-pieces 
should be employed at each end, as 
shown in Fig. 118, instead of outlet 
syphons, which would render the cur- 
rent unequal, but if placed side by side the syphons will 
answer best. 
Boilers.— There are now a considerable number of 
boilers—or to speak more correctly, heaters, their purpose 
N 
Fie, 126, 
Fig. 117. 
