334 '^he American Geologist. November, i-jui 
Another Kansas Meteorite. Still another meteorite has 
recently been added to the list of finds and falls for which 
Kansas is becominsg- celebrated. The last reported find is from 
Admire. Lvon county ; a stony iron of the type referred by 
Brezina to the Rokicky j^roup. The only other representa- 
tive of this g^roup yet found in America, is that of Eagle Sta- 
tion, Carroll county, Kentucky. 
The date of the fall of the Lyon county specimen is un- 
known, but its badly oxidized condition indicates that it has 
been lying in the ground for many years. 
St)me twelve kilograms of the material has thus far com.j 
into the possession of the National Museum at Washington, 
but the entire amount of the fall cannot be accurately as- 
certained. It will be known as the x\dmire meteorite. 
Difficulties of Deep Coal Mining. In an article 
recentlv read before the North Staffordshire Institute 
of Mining and Mechanical Engineers (England), by 
Mr. Percy Turner upon the subject of "Coal Mining at 
Depths Exceeding 3.000 Feet." he discusses the subject un- 
der the following heads: ist. Increase in Temperature; 2d, In- 
crease in Pressure ; 3d. Winding Difficulties ; 4th, Increased 
Expenditure. His conclusions are as follows : "The depth, 
then, to which coal mines may extend (le])ends ui)on human en- 
durance of high temperatures, upon the possibility of reducing 
the humidity and temperature of the air, and upon the liabilit}' 
to gob fires. The possible working of very thick seams (from 
15 to 30 feet) appears to be less than seams up to seven feet in 
thickness. Owing to the im])racticability of completely pack- 
ing horizontal thick seams, and the consequent necessity of sup- 
porting the roof with timber, and of finally allowing it to 
break dcwn, instead of settling as it would if the goaf wen' 
packed, the effect of pressure becomes a serious matter. In- 
deed at 2,000 feet the difficulties are considerable, and at a 
depth of 3,000 feet, tluy would probabl)- be such as to render 
packing impracticable. 
The possible depth from which coals can be worked does 
not appear to be limited by any consideration of a mechanical 
nature. With regard to drainage, it has been proved in mcxst 
Cornish mines that the volume of water does not incirease be- 
vond a certain i)oint. with increased depth. The comparatively 
shallow depths intercept most of the water, leaving only a fixed 
quantity to deal with in the sump. In the coal fields, water is 
rarelv if ever, met with at great depths. 
The limit of depth taken by Prof. E. Hull, in i860, and bv 
the Royal Coal Commission, in 1870. was 4.000 feet. Prof. W. 
Galloway, however, savs "it is probable that a depth of at least 
8.000 feet will be attained, even in those localities in which th<' 
rate of increase is as much as T degree Fahr. in 60 feet."' 
— Mines and Minerals. 
