74 MANAGEMENT OF THE FORCING-HOUSE,. 
periments are given. * * * No effort has been made 
to select examples, further than to secure a fair average, 
rather than to present the highest or the lowest. The 
average gain of the sub-irrigated over the surface-watered 
in the above cases was a little more than 4o per cent. 
This increase in weight was made in a little more than 
six weeks, or from the time the plants were set in the 
benches to the end of the experiments. That is, all of 
the plants were sub-irrigated while growing in the flats, 
or during about half of their period of growth, and not un- 
til they were planted in the benches was surface-watering 
commenced. This is a less favorable showing for sub- 
irrigation than is made in the last table, by the plan 
above described, of carrying the plants through the entire 
period of growth by the respective methods of watering.— 
RESULTS IN FIFTEEN SUB-IRRIGATION EXPERIMENTS 
WITH GRAND RAPIDS LETTUCE. 
Surface-watered. Sub-irrigated. 
Experiment. 
Number of | Weight, | Number of | Weight, 
plants. ounces. plants. ounces. 
Dee parr) TA, 140 474 140 637 
I es eee wore 100 374 100 512 
MU Op eet See nae ge ae 75 287 | 75 383 
WV crcc ths peas 100 299 100 453 
IW wetescte: Fe ct Sater 55 297 | 55 340 
Wiles hasan site nce 100 545 | 100 602 
Wile ec e rc 25 132 25 176 
VA hoe Be tte eee 2 25 121 25 | 130 
DOK! Boeke Goel oN 35 212 35 242 
PRON 2 ols Maen 150 477 150 572 
Gl Lage REN at on ns 107 554 | 107 644 
> ANG repens camera 144 | 262 144 337 
PUTT a as ios tora eoran 32 107 32 147 
DOIN, ey cs ek is asa 96 280: . | 96 380 
P<) EE aan ig tee aoe 160 156 | 160 452 
‘“‘In the above examples, the surface- and sub-irrigated 
plots were side by side, but a more satisfactory plan is to 
