354 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



tion of the geological characteristics, chemical composition, 

 and agricultural uses of the marls of that state. The sen- 

 eral conclusions as to the agricultural value of the sreensand 

 marls which are the most important arc, in substance, that 

 (1) those containing the largest percentage of phosphoric acid 

 are the most valuable; (2) those rich in carbonate of lime 

 are the most durable; (3) the potash in them has but very 

 little, if any, present value, it being combined with silica, 

 and hence insoluble; (4) the greensands, containing but lit- 

 tle of either phosphoric acid or carbonate of lime, become 

 active fertilizers when composted with quicklime ; (5) the 

 injurious effect of sulphate of iron in the marls can be coun- 

 teracted by composting with lime ; (6) the crops particu- 

 larly improved by them are all forage crops (grass, clover, 

 etc.), potatoes, buckwheat, wheat, rye, oats, and corn. The 

 Tertiary and calcareous marls seem to be very useful, but 

 less so than the greensand. 



Percolation of Water through the Soil, and Consequent Loss of 



Plant-Food. 



The Scientific Farmer reports some very interesting and 

 instructive experiments by Dr. Sturtevant on the relation 

 between the amount of water which falls in rain and that 

 which percolates through the soil. These are made by means 

 of a lysimeter with an area of one five-thousandth of an acre, 

 on the plan of those performed at Rothamstead, in England, 

 and other places in Europe. The soil was a gravelly loam. 

 The total rainfall during the year 1876 was 43.88 inches, of 

 which only 4.76 inches leached through to a depth of twenty- 

 live inches. That is to say, only 11 per cent, of the total 

 amount of water which fell percolated to this depth; while 

 in European experiments (under varying conditions of soil- 

 depths at which tests were made, etc.) the percentage of per- 

 colation varied from 20 to 42.5 per cent. Dr. Sturtevant 

 infers that the waste of fertilizing elements from New Eno-. 

 land soils by drainage must be much less than in England. 



Loss of Plant -Food through Rivers. 



Breitenlohner and Harlacher calculate that the river Elbe, 

 which takes up all the Bohemian rivers, and carries off five 

 milliards of cubic meters of water per annum, takes with this 



