=Alkali Soils in Montana.=--Mr. F. W. Traphagen, of the Montana Agricultural Experiment Station, ascribes the origin of the alkali soil in the arid regions to the failure of the elements to remove the soda salts set free on the disintegration of the rocks, which in humid regions are taken up and washed away by the rains. The soluble salts are dissolved by the water that falls on the surface, and are carried down when it soaks through the ground, to form an element in the ground water. They return thence to the soil when water is brought up by capillary action to supply the place of that lost by surface evaporation, and accumulate there. Then, as the water evaporates they are left on the surface, forming, when in sufficient quantity, the white crusts seen in badly alkalied places. The most effective remedy for alkali might probably be found in underdrainage, which would prevent the ground water rising to the top, and would carry off the salts. This being at present impracticable on the large scale that would be required, such expedients as surface flooding and such cultivation of crops as would tend to check evaporation are suggested. The pernicious effects of “black alkali” or sodium carbonate are seen when it forms as much as about one tenth of one per cent of the soil, in the corrosion and solution of vegetable matter--the stems of plants--exposed to it. It also dissolves the humus or vegetable mold, forming dark-colored solutions and depositing a black residue upon the evaporation of the water--whence its name--and it destroys the tillability of many soils. The “white alkali” or sodium sulphate can be borne in much larger proportions in the soil, and promotes the best crops just before it completely destroys them. The author remarks that the foundations of a number of buildings in Billings, Montana, are gradually becoming insecure because of the disintegration of the rock, due to the absorption of alkali salts, followed by the evaporation of the water and the deposit of salts within the pores of the rock. As the process continues, the rock particles are forced apart. * * * * *