DETAILS OF SUB-IRRIGATING. 7 jo! 
come above the top of the bench, in order to admit of 
inserting the hose in watering. When the tiles are laid 
crosswise the benches, several may be watered at once by 
means of a piece of gas pipe with holes bored at suit- 
able distances. When the tiles are laid, they are simply 
placed end to end, and no cement is needed, although it 
is sometimes used to prevent the tiles becoming dis- 
placed in filling the benches with soil. 
“Gas pipe, with holes bored at intervals, has been 
used with success; also a pipe, called ‘structural iron 
pipe.’ This differs from ordinary iron pipe in having a 
slot along one side. Where the slot is nearly closed, so 
as to not allow the water to flow too freely, this pipe 
answers very well, but 2%-inch drain tiles are cheaper 
than anything else, and are perfectly satisfactory. These 
tiles are, of course, removed and put in place again each 
time the soil in the benches is renewed. Another thing 
in favor of 2% or 3-inch tiles, is that the capacity is suffi- 
cient, so that it may be filled quickly and the operator 
may go on to another tile, allowing the water to soak 
out into the soil, knowing that enough has been given to 
last several days; but if iron pipes are used, the size 
must be small because of the cost, and the watering must 
be more frequent in consequence.”’ 
Rane speaks as follows (Bull. 33, W. Virginia Station) 
of the equipment of the sub-irrigation bench: ‘‘ The ques- 
tion of economy, when considering the advisability of using 
sub-irrigated beds, is justly a worthy and important one. 
There must be a water-tight bed to retain all the water in 
the soil, the construction of which is necessarily more 
expensive than in the ordinary method of making beds, 
provided boards are used. The pipe or tiles are likewise 
an extra expense. Now, will this expenditure be realized 
from the advantages gained? The cost of raw material, 
for example, in two houses, each 50 ft. long and 20 ft. 
wide, one being arranged for surface and the other for 
under-surface watering, would be about as follows: 
