4 BouyoucoB, Transpiration of Wheat Seedlings as Aflfected etc. 



each basket, aud pressed firmly at the bottom and at their sides so 

 it would form a very close contact with the walls. The baskets were 

 next dii)ped several times in melted paraffine slightly above the 

 lower edge of the jiaraffined rini, until a thick coating was formed 

 which cemented the outer surface of the niass of soil to the walls 

 of the pots. The soil was next brought iip to the desired nioisture 

 content by the addition of a certain amount of the Solution and 

 then an equal number of well selected seeds were ])lanted in each 

 pot, the weight of the pot being then recorded. When the seeds 

 were germinated and the seedling-s were about one inch in heig'ht, 

 each basket was reweighed and the loss in weight was replenished 

 by the addition of water. Then an equal number of the healthiest 

 and most vigorous seedlings of as near as possible the same size, 

 were selected and the remainder pulled out. The baskets were 

 next sealed and their final weight recorded. 



The sealing of the baskets was done somewhat differently 

 from that recommended by the Bureau of Soüs. The new niethod 

 was devised in the course of the investigation and cousisted of 

 placing- over the selected seedlings small glass tubes with a dia- 

 nieter sufficiently large to permit the fitting of the seedlings through 

 them, and then melted paraffine was poured over the surface of 

 the soil. The glass tubes, being pushed a little below the surface 

 of the soil, prevented the hot paraffine from coming in contact 

 with the seedlings and thus injuring them. 



This method has given very satisfactory results and is probably 

 the better of the two, for the following reasons: 1) it takes less 

 time to seal each basket; 2) it reduces the evaporation from the 

 sui'face of the soil more, because it forms a better uniform cover; 

 it gives less amount of exposed surface of the soil through the 

 holes; it creates a closer contact between the surface of the soil 

 and the cover; and 3) it reduces to the minimum the possibility 

 of inJury to the plants during manipulation. 



The only serious objection to this method is that if the 

 paraffine is too warm it may heat the glass tubes. and if the seed- 

 lings are in close contact with them, they maj^ probably be scalded. 

 This danger can be easily avoided, however, by placing over the 

 glass tubes very thin rubber tubing before they are placed over 

 the plants, and also by not using too warm paraffine. 



Just as in the case of the water cultures, the baskets were 

 weighed at intervals of from three to four days and the loss in 

 weight was attributed to transpiration. The loss was replenished 

 in this case not by the Solution as in the case of the water cul- 

 tures, but by distilled water only. 



The sand cultures were prepared and conducted exactly like 

 the above, excepting that the sand was added in the baskets after 

 they were entirely paraffined. 



The seed employed throughout the work was Pringels Champion. 

 In Order to eliminate errors which are due to inherent differences 

 in the individuality of the plants, a large number of seedlings of 

 the same variety was used for the different kinds of cultures withiu 



