718 EXPERIMENT STATION RECORD. [Vol.40 



conditions. Provision for a surface inlet for the removal of water from above 

 the dam and a proper foundation are deemed essential to the success of any 

 type of dam. 



The estimated cost of installing the various control methods outlined is pre- 

 sented in each case. 



Recent investigations on soil aeration, A. Howard and R. S. Hole (Agr. 

 Jour. India, 13 {1918), No. 3, pp. 416-UO, pis. 6, figs. 7; abs. in Chcm. Ahs.. 13 

 (1919), No. 1, p. 51). — This article reviews investigations by the authors and 

 others showing the importance of soil aeration in crop production and forestry. 



Vegetation on swamps and marshes as an indicator of the quality of peat 

 soil for cultivation, T. J. Duxxewald (Jour. Amcr. Soc. Apron., 9 (1917), No. 

 7, pp. S22-32.' f ). — This paper, a contribution from the Wisconsin Experiment 

 Station, briefly describes field observations made on scattered marshes and 

 swamps in the northwestern part of the State, supplemented by a laboratory 

 examination of representative samples of peat bearing different classes ><f 

 vegetation, in an effort to determine whether chemical conditions favorable 

 or unfavorable to cultivated crops obtain in different areas of peat and whether 

 the vegetation parallels such conditions. 



The field studies indicated that spruce and tamarack peat areas were the 

 wettest, having the water table practically at the surface of the soil, and pos- 

 sessed a covering of from 12 to 18 in. of spongy moss. The depth of the peat, 

 distance from shore, and extent of decomposition of the peat appeared to have 

 little effect on the kind of surface growth. While the rawest samples of peat 

 occurred in the spruce and tamarack areas, it is stated that as often the 

 peat was as well decomposed on these areas as under elm, birch, ash, or grass. 



The laboratory analysis indicated that peat bearing black spruce and 

 tamarack had approximately 20 per cent less mineral matter, a much greater 

 degree of acidity (Truog method), and somewhat less nitrogen than that from 

 areas bearing various mixtures of ash, lurch, balsam, poplar, elm, cedar, tama- 

 rack, willow, pine, or grass. As a result of these observations, the author eon- 

 eludes that " while the greater acidity present in the spruce and tamarack peats 

 may be due to more continued flooded conditions on those swamps, and while 

 drainage experience shows that this acidity often disappears largely after the 

 drainage and cultivation of the peat, we believe the data support the farmer's 

 statement that such trees as ash, elm, birch, and white pine on peat indicate 

 a better quality of the material than that where only black spruce, tamarack, 

 sphagnum moss, blaeberries, and cassandra grow." 



A study of soil solutions by means of a semipermeable membrane sup- 

 ported on a porous clay plate, (J. L SCHUSTER (Jour. Amcr. Soc. Agron., 9 

 (1917), No. 7, pp. 333-340, pi. 1, figs. 3).— This paper, a contribution from Ohio 

 State University, describes experimental work undertaken in an effort to deter- 

 mine the concentration of the soil solution in terms of a given sugar solution by 

 means of a copper ferrocyanid membrane supported on a porous clay plate. 

 The preparation of the membrane and its use in these studies are described. 



Samples of sandy loam, muck, and clay soils were taken from the surface 6 

 in. and placed in cylinders in as nearly a natural condition as possible, and the 

 strength of the soil solution measured against that of a 5 per cent sugar solu- 

 tion in the case of the sandy loam and clay, and a 2 per cent solution in the case 

 of the muck. The experiments were conducted in duplicate and frequent read- 

 ings made on graduated pipettes of the rise In the sugar solution. Although 

 the data are regarded as rather limited they are held to indicate that " the 

 concentration of the soil solution (measured in terms of osmotic pressure) 

 in sandy loam and clay appears to he below that of a 5 per cent sugar solution 

 and that of muck below that of a 2 per cent solution." 



