Editorial Comment. 45 
described it as loess . Whatever it is i a the geological classifi- 
cation matters not to the practical farmer, as he reaps bountiful 
harvests from it. 
Alkali lands are caused by standing water. A tract thorough- 
ly drained will never be permanently alkaline. Underdraining is 
better than surface draining, because it tends to draw the mois- 
ture downward from the surface. The opposite result occurs 
where standing water evaporates. Not only are the alkalies in 
the water precipitated as the evaporation proceeds, but more 
alkali is brought up from beneath by the ascending moisture. 
Drainage and tree-planting will cure nearly all the alkali patches 
in Nebraska. 
EDITORIAL COMMEN' 
The Exhaustion of Anthracite Coal . 
In 1880 Mr. P. \V. Sheafer, of Pottsville, Penn., made esti- 
mates of the amount of anthracite coal remaining in the three 
fields of Pennsylvania,* viz. 
Area, square 
miles, Acreage. 
First; or Southern coal-field 14fi 93,440 
Second, or Middle coal-field 126 80,640 
Third, or Northern coal field 198 126,720 
Total 470 300,800 
Yards. Tonnage. 
First, average total thickness of beds 25 11,806,240,000 
Second, average total thickness of beds 15 5,854,464,000 
Third, average total thickness of beds 15 9,199,872,000 
Total tonnage 26,360,576,000 
Amount to be mined, one-third 8,786,858,666 
Total shipments to January 1st, 1888 628,612,720 
Adding 10 r local sales and amount used at mines as per Geol. Rep. 
(1887, est'd 6 per cent.) 53,119,40 
Total production to January 1st 1888 681,732,129 
Present available supply, workable S, 107,125,537 
At present rate of production would last 202 years. 
With maximum rate of production from 1890 (50,000,000 tons), 
would last 162 years. 
From which he conludes: 
The total amount of coal still to be mined is 26,300,578,000 tons. The 
total -waste, as experience has shown, is equal to two-thirds of the coal 
deposit, and reaches the appalling amount of 17,573,717,334 tons, leaving 
♦American Association for the Advancement of Science. Proceedings, 
1880. 
