9 



per cent, on the "basis of dry weijfeht. This particular soil 

 with this water content was rather too wet than too dyy for 

 the best growth of the plants here studied. 



After preparing the v>ots and arranging the watering de- 

 vices the pots were then allowed to remain fallow for about 

 two weeks before planting. Thus the soil v/as fully drained 

 after the preliminary saturation £.nd had settled into a con- 

 dition somewhat approaching that of structure equilibrium 

 before the seeds wore planted. The seeds were planted 2.5 cm. 

 deep, six seeds in each pot. Oare was taken to space them un- 

 iformily and to place them about equally distant from the auto- 

 irrigator cups and from the sides of the pots so that all should 

 have, as nearly as possible under the conditions of the exper- 

 iment, the same soil moisture conditions, "^hen the plants 

 v;ere removed from a pot fabout six weeks after that pot had 

 been filled) the soil was discarded and fresh soil from the 

 stored supply Y/as used in refilling for the next folloT-rin^ 

 culture . 



The weather observations taken by the cooperative ob- 

 servers at each of the sta'^ion here employed consisted of dailv 

 readings of maximum and minimum thermometers, daily ocular 

 observations of cloudiness, daily measurements of rainfall 

 and general notes as to storm.s, winds, etc. In addition to 

 these records of the weather observers evaporation was ;neasured 

 by means of Livingston standardized cylindrical oorous cuns 

 with non-rain absorbing mountings. Of the fiv^ sets of climatic 



J^ 



Livingston, B. S. , A rotating rabl§ for standardizing 



porous cup atraometers. Plant V,'orld l.>. i:)' -162.1912. Idem, 



