GLASS    SAND    OF    MIDDLE    MISSISSIPPI    BASIN. 
basin  of  possible  value  for  glass  making. 
States  Geological  Survey.] 
463 
Constituent. 
Silica  (SiOg). 
Magnesia  (MgO). 
Lime  (CaO). 
Oxide  of  iron 
(Fe203). 
Uumina 
(Al,<>3). 
Total. 
Per  cent . 
97.59 
98.00 
97.  50 
97.94 
97.08 
97.80 
96.45 
Per  cent. 
Per  cent . 
Per  cent. 
0.  33 
.37 
.43 
.  63 
.72 
.84 
.37 
.07 
.09 
.22 
.07 
.07 
Per  cent. 
P(   '  Ct  ill 
!i7.  92 
os.  37 
99.  05 
98.57 
97.  SO 
98.  04 
99.  58 
99.60 
99.  77 
99.  64 
99.  54 
99  75 
0.10 
1.62 
2.70 
2.  03 
.13 
.25 
96.90 
99.  55 
99.  17 
99.47 
99.52 
.16 
Sieve  tests.     (  Percentages  are  approximate.) 
Larger  than  20  mesh. 
Small  lumps. 
....do 
do 
do 
Few  small  lumps. 
Few  lumps 
....do 
A  few  grains 
....do 
1+per  cent 
Fin?  lumps 
1 'asses 
20  mesh. 
Per  cent. 
100 
100 
100 
100 
100 
100 
100 
100 
99+ 
99+ 
98+ 
100 
Passes  Passes 
40  mesh.        00  mesh. 
Per  cent. 
99 
100 
85 
80 
100 
100 
100 
1C0 
97 
80 
35 
Pt  /•  i  f  a! . 
60 
05 
35 
00 
95 
80 
100 
90 
50 
40 
6 
80 
Passes 
100  mesh. 
Per  ct  ni . 
15 
20 
10 
15 
35 
20 
90 
50 
10 
15 
1- 
10 
