345 



by the rain gaii^e; (3) supplied artificially, either by surface watering 

 or by watering from below, ?. e. pouring water into the glass tube; (4) 

 removed as drainage water througli the tube. The height of the water 

 table (gr<uind water), which was occasionally raised by pouring water 

 into the tube, was also noted. By adding the amounts su])plied by 

 rain and artificial watering and subtracting fiom this sum the anu^unt 

 removed by drainage, allowance being made for change in the height 

 of the water table, an estimate was made of the amount which eseai)ed 

 by evaporation from the surface of the soil and by transpiration through 

 the plant. To make the estimates accurate, determinations of the 

 moisture at the end as well as at the beginning of the experimental 

 period would have been necessary, but such determinations were not 

 convenient, and it was thought that the error would not be large 

 enough to rob the estimate of value as a general indication of the 

 amounts of water which escape from plant and soil under similar condi- 

 tions in ordinary field culture. 



In a number of the specimens of drainage water determinations were 

 made of the proportions of nitrogen, phosphoric acid, and potash. 



Dr. Wohltmann began the exi)eriments in 1885, repeated them in 



1886, and was then comiielled by illness and absence from Gennany to 

 leave them. They were continued in 1887 by Dr. H. Schefifler. But 

 the labor involved was large, and, what was still more serious, leaks 

 appeared in a number of the boxes, thus interfering with the studies of 

 moisture supply and drainage, .and the investigation was therefore 

 given up. The boxes of soil have since been used for the study of dis- 

 eases of i)lants, to which the experimental work of the institute is 

 especially devoted and for which these arrangements are well adapted. 

 The experiments of 1885 and 1886 were reported by Dr. Wohltmann in 



1887. Those of 1887, with final conclusions, have just been published. 

 The whole memoir, which fills some 240 quarto pages of text, is supple- 

 mented by numerous and extensive tables of numerical details. 



ResulU of the experiments. — The experiments with beans and lupines 

 were unsuccessful, partly because of diseases for which no adequate 

 remedy was found and partly for reasons which could not be explained. 

 The lupines developed very unequally in the duplicate boxes. Dr. 

 Wohltmann attributes this to individual ditferences in the plants and 

 thinks that the lupine can hardly be regarded as a suitable plant for such 

 experiments as these (in which relatively few jilants are used for each 

 trial) until means shall have been found, by studies of the seeds or 

 otherwise, \o secure like plants for all the trials of the experiments. In 

 the compilatiou of average results the beans and lupines were left out 

 of account. 



The exi^eriments with barley, oats, wheat, and peas were in the main 

 successful, though in a few instances the plants were injured by dis- 

 eases. In several cases, in which the germinating seeds or very young 

 plants were thus affected, second sowing was resorted to. The cases in 



