1905] LIVINGSTON—TRANSPIRATION._ AND GROWTH 181 
paper, were carried out in the laboratories of the Bureau of Soils of 
the United States Department of Agriculture, Washington, D. C. 
I am indebted to Professor Mitton Wuuirtney, to Dr. F. K. 
CAMERON, and to all the members of the laboratory staff for facilities 
and assistance without which the work could not have been done. 
Especially am I indebted to Mr. FRANK A den 
D. GARDNER, in charge of the Division ee 
of Soil Management, for cultures from us ee et 423, 
which a number of the series were pM a eT 
F 
obtained, and for the data themselves 
in case of Series IV to X inclusive. 
EXPERIMENTS. 
The cultures will be 
described in the follow- 
ing paragraphs. It is to 
be remembered that for 
any single series the only 
environmental factors op £09 
28a is O95 a9 OPT 
which were varied are "aes 0.935 Se ee eer gga wae 
those connected with the ; 
i 2 3 4 5 6 : ¢ 
nature of the medium in 
which the roots were 
growing. The criteria for comparing the growth of the different 
cultures of a series are (1) total transpiration during the period of 
the experiment, (2) green weight of tops and (3) of leaves, and (4) 
area of leaves. In these studies aerial growth alone is considered, the 
investigations into the growth of roots being reserved for another paper. 
Series I—A very poor natural soil from Takoma Park, Md., was 
used in this series. Basket no. 1 contained the natural soil = os 
others the same soil mixed with fermented stable manure in different 
amounts. The plants were weighed at intervals of from one to three 
days. The experiment lasted from October 25 to November 2 
*904- A photograph of the series at the end of the experiment 1s 
shown in fig. z. Data for the series are given in the following table. 
The baskets are arranged according to the total transpiration for the 
period of the experiment. 
These data are best presented in the form of curves (fig. 2). 
FIG. 2 
