B ouyoucos, Transpiration of Wheat Seedlings as Affected etc. 
5 
the same experiment. Special care was also taken to select seed¬ 
lings of nearly uniform size and of the same vigor and health, as 
possible. 
Experimental Results. 
As already stated the object of this line of investigation was 
to determine the effect of different densities of a complete nutrient 
solution on the amount of water transpired by wheat seedlings per 
unit of dry matter produced. For this purpose the wheat plants 
were grown in solution, sand and soil cultures, containing various 
densities of a full nutrient solution. The concentrations of this 
solution were seven in number, and ranged in strength front 0.0 
to 4500 parts per million. The sand and soil cultures were used 
first to duplicate the water cultures, and secondly, to see whether 
the different densities of the solution would affect the transpiration 
in these cultures, in the same Order or in the same magnitude as 
in the water cultures. For the determination of these two points, 
all the three different kinds of cultures were conducted at the 
same time and under the same conditions, in order that their results 
might be comparable. The sand and soil employed were of various 
sized particles. The sand consisted of three different sizes, namely, 
numbers, 1, 2 and 3 1 / 2 . In other words, those which could pass 
through a mesh of 1, 2 and 3^2 millimeters respectively, in diameter. 
The soil consisted of a Dunkirk clay loam and of a Dunkirk sandy 
loam, the first being assumed to be the finer of the two. The 
object of employing the sand and soil of different textures, was to 
ascertain whether the size of particles exerted any influence upon 
the density of the solution in affecting the transpiration. To in- 
vestigate this point, the cultures of the various sizes of sand, and 
of the two soils, were carried on at the same time, and under the 
same conditions. This part of the work, however, will be reported 
elsewhere. 
In order to obtain definite and conclusive evidence on this 
part of the investigation, the three different kinds of cultures were 
repeated a large number of times. The solution and sand cultures 
were made five times each, and the soil cultures two times, 
Inasmuch, however, as there were two different sizes of sand 
in four out of the five cases, and two different kinds of soil in 
both instances, and since all received the same treatment, there 
were really nine sand and four soil cultures, respectively. The 
solution cultures conducted at the different times, contained in each 
density, from three to five bottles with four plants in each receptacle. 
The sand and soil cultures, also carried on at different periods, 
contained in each density, from three to six baskets, with five to 
six plants in each. The total number of plants in each concen- 
tration in the different cultures was, therefore, 96 in the five so¬ 
lution cultures, 204 in the nine sand cultures and 80 in the four 
soil cultures. 
