4 Bouyoucos, Transpiration of Wheat Seedlings as Affected etc. 
eacb basket, and pressed firmly at tbe bottom and at their sides so 
it would form a very close contact witb tbe walls. Tbe baskets were 
next dipped several times in melted paraffine sligbtly above tbe 
lower edge of tbe paraffined rim, nntil a tbick coating was formed 
wbicb cemented tbe outer surface of tbe mass of soil to tbe walls 
of tbe pots. Tbe soil was next brougbt np to tbe desired moisture 
content by tbe addition of a certain amount of tbe solution and 
tben an equal number of well seleeted seeds were planted in eaeb 
pot, tbe weigbt of tbe pot being tben recorded. Wben tbe seeds 
were germinated and tbe seedlings were about one incb in beigbt, 
eacb basket was reweigbed and tbe loss in weigbt was replenisbed 
by tbe addition of water. Tben an equal number of tbe bealtbiest 
and most vigorous seedlings of as near as. possible tbe same size, 
were seleeted and tbe remainder pulled out. Tbe baskets were 
next sealed and tbeir final weigbt recorded. 
Tbe sealing of tbe baskets was done somewbat differently 
from tbat recommended by tbe Bureau of Soils. Tbe new method 
was devised in tbe course of tbe investigation and consisted of 
placing over tbe seleeted seedlings small glass tubes witb a dia- 
meter sufficiently large to permit tbe fitting of tbe seedlings tbrougb 
tbem, and tben melted paraffine was poured over tbe surface of 
tbe soil. Tbe glass tubes, being pusbed a little below tbe surface 
of tbe soil, prevented tbe bot paraffine from coming in contact 
witb tbe seedlings and tbus injuring tbem. 
Tbis metbod bas given very satisfactory results and is probably 
tbe better of tbe two, for tbe following reasons: 1) it takes less 
time to seal eacb basket; 2) it reduces tbe evaporation from tbe 
surface of tbe soil more, because it forms a better uniform cover; 
it gives less amount of exposed surface of tbe soil tbrougb tbe 
boles; it creates a closer contact between tbe surface of tbe soil 
and tbe cover; and 3) it reduces to tbe minimum tbe possibility 
of injury to tbe plants during manipulation. 
Tbe only serious objection to tbis metbod is tbat if tbe 
paraffine is too warm it mayheat tbe glass tubes, and iftbe seed¬ 
lings are in close contact witb tbem, they may probably be scalded. 
Tbis danger can be easily avoided, bowever, by placing over tbe 
glass tubes very tbin rubber tubing before tbey are placed over 
tbe plants, and also by not using too warm paraffine. 
Just as in tbe case of tbe water cultures, tbe baskets were 
weigbed at intervals of from tbree to four days and tbe loss in 
weigbt was attributed to transpiration. Tbe loss was replenisbed 
in tbis case not by tbe solution as in tbe case of tbe water cul¬ 
tures, but by distilled water only. 
Tbe sand cultures were prepared and conducted exactly like 
tbe above, excepting tbat tbe sand was ' added in tbe baskets after 
tbey were entirely paraffined. 
Tbe seed employed tbrougbout tbe work was Pringels-Champion. 
In order to eliminate errors wbicb are due to inberent differences 
in tbe individuality of tbe plants, a large number of seedlings of 
tbe same variety was used for tbe different kinds of cultures witbin 
