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I ' 


Topographic and Geologic Survey 

of Pennsylvania 

RICHARD R. HICE, State Geologist 


Glass Manufacture 


Glass Sand Industry 









o T 


Topographic and Geologic Survey 

of Pennsylvania 

RICHARD R. HICE, State Geologist 


Glass Manufacture 


Glass Sand Industry 











GEORGE W. McNEES, Chairman, Kittanning. 
ROSWELL H. JOHNSON, Pittsburgh. 

KIOHARD R. HICE, State Geologist, Beaver. 







Letter of transmission 17 

lutrodaction , 19 

Chapter I. Definition and composition of glass, 21 

Cliapter II. Classification of glasses ' 27 

Chapter III. Chemical properties of glass, 29 

Chapter IV. Physical properties of glass, 33 

Chapter V. Raw materials of glass manufacture, 38 

Acid oxides 38 

Silica, 38 

Boric acid, 67 

Phosphoric and Arsenious acids, 67 

Bases, 68 

AlkaUes. 68 

Sodium oxide, 68 

Potassium oxide, 72 

Lithium oxide, 73 

Lime, 73 

Magnesia, 76 

Barium oxide, 76 

Strontium oxide, 77 

Zinc oxide, 77 

Lead oxide, 78 

Alumina , 79 

Thallium, .-: 79 

Igneous rocks and slags, 79 

Clarifiers, 80 

Arsenic trioxidc, 80 

Soda nitre, 81 

Nitre, 81 

Vegetable substances, 81 

Decolorizing agents, 82 

Manganese dioxide, 82 

Selenium, 83 

Coloring agents, 84 

Violet color, 84 

Manganese dioxide, 84 

Nickle oxide, , 85 

Blue color, 85 

Cobalt oxide, 85 

Copper oxide, 85 

Green color, 85 

Ferrous oxide, 85 

Copper oxide, 86 



Chapter VI. 

Chapter VII. 

Chapter VIII. 

Chapter IX. 
Chapter X. 
Chapter XI. 

Chapter XII. 
Chapter XIII. 

Chapter XIV. 

Chapter XV. 

Chromium oxide, 86 

Uranium oxide, 86 

Yellow color, 87 

Ferric oxide, 87 

Sulphur, 87 

Cerium oxide, 87 

Uranium oxide, S7 

• Silver, 87 

Red color, 88 

Copper oxide, 88 

Gold 88 

Selenium, 80 

Opacifiers, S9 

Calcium phosphate, - , 89 

Fluorine preparation , 89 

Tin oxide, 89 

Preparation of the batch, 90 

Composition of the batch, 90 

Methods of calculating glass batches, 93 

Mixing of the batch , 96 

Fuel, 97 

Natural gas , 97 

Producer gas , I'X) 

Pots and furnaces for the fusion of glass, 106 

Fire clay 106 

Silica brick 109 

Manufacturing of tank blocks, 110 

Pot furnaces, 114 

Manufacturing of tank blocks, 116 

Tank furnaces, 117 

Relative merits of tank and pot furnaces 118 

The process of fusion , 120 

Annealing, 125 

Process used in the working of glass, 128 

Bottle glass, 128 

Blown and pressed glass, 132 

Window or sheet glass , 136 

Rolled or plate glass, 139 

Optical glass 143 

Statistics of the glass industry of Pennsylvania, 147 

Glass sand deposits of Pennsylvania 149 

Introduction , 149 

Location of the Industry , 149 

Formations involved, 149 

The Oriskany formation , 161 

Character of the distribution of the Oriskany formation, 151 

Geologic History of the Oriskany formation, * 158 

Oriskany glass sand deposits 163 

Characteristics due to conditions of original deposition, 163 

Characteristics due to secondary changes, 166 


Preparation of the sand for market, 173 

Examination of undeveloped areas, 174 

Distribution of the workable deposits in Pennsylvania , . . . 176 

Chapter XVI. Glass sand deposits of Huntingdon CJounty, 177 

Location of outcrops, 177 

Workable portion, 1T8 

History of the glass sand industry in Huntingdon County, 192 
Description of glass sand quarries and plants in operation, 193 
Mapleton Works of the Pennsylvania Glass Sand Com- 
pany, 193 

Keystone Works of the Pennsylvania Glass Sand Com- 
pany , 195 

Columbia Works of the Pennsylvania Glass Sand Com- 
pany, 100 

Pittsburgh White Sand Company, 107 

Juniata White Sand Company, 100 

Hummel Sand Company, -. 200 

Undeveloped areas, 201 

Chapter XVII. Glass sand deposits of Mifflin County, 203 

Location of outcrops, 203 

Workable portions, 203 

History of the glass sand industry in Mifflin County, . . . 211 
Description of glass sand quarries and plants in Mifflin 

County, 213 

Juniata Works of the Pennsylvania Glass Sand Com- 
pany, 213 

Hatfield Works of the Pennsylvania Glass Sand Com- 
pany , 215 

Enterprise Works of the Pennsylvania Glass Sand Com- 
pany, 216 

Crystal Sand Company, 217 

John Miller's Sand Mine at Burnham, 218 

Chapter XVIII. Gloss sand deposits of Oriskany age in other parts of Central 

Pennsylvania , 220 

Bedford County, 220 

Blair County, 222 

Carbon County, 222 

Centre County 222 

Monroe County, 223 

Chapter XIX. The Pottsville formation, 224 

Character and distribution of the Pott8\'ille formation, . . 224 

Geologic history of the Pottsville formation, 231 

Chapter XX. Pottsville glass sand deposits, 235 

Preparation of the sand for market, 237 

Examination of undeveloped areas, 238 

Distribution of the workable deposits in Pennsylvania, 239 

Chapter XXI. Description of glass sand quarries in Pottsville of Penn- 
sylvania , by counties, 240 

Clearfield County 240 

Elk County 240 

Fox Silica Sand and Stone Company, 241 

Ridgway Sand and Stone Company, 242 



Ridgway-Croyland Silica Ck>mpany, 243 

White SiUca Sand Company, 244 

Fayette County, 245 

Dunbar Furnace Company, 245 

Yough Sand and Stone Company, 246 

Forest County, 247 

Spring Creek Glass Sand Company, 248 

Jefferson County, 249 

Falls Creek Sand and Stone Company, 249 

Gocella Stone and Sand Company, 260 

Jefferson and Clearfield Stone and Sand Company, 250 

Silica Stone and Sand Company, 251 

McKean County, 252 

Venango County, 252 

Pittsburgh Plate Glass Company, 252 

Venango Sand and Stone Company, 254 

Warren County , '. 255 

Warren Silica Company, ^. 255 

Altham Sand Company , 257 

Portlieuum Sand Company, 257 

Westmoreland County , 258 

American Window Glass Company 258 

Derry Glass Sand Company, 260 

Millwood Glass Sand Company, 260 

Chapter XXII. Other glass sand deposits in Pennsylvania, 262 

River terrace sand, 262 

The Tuscarora sandstone as a possible source of glass sand, 262 

Bibliography, 264 

Index 271 



Plate I. 
Plate II. 

Plate III. 

Plate IV. 

Plate V. 

Plate VI. 

Plato VII. 

Plate VIM. 

Plate IX. 

Plate X. 

Plate XI. 


Gclstharp and Parkinsons Diagram, *. 26 

Figure 1. Sand dunes along dry channel of Rio Puerco, 

south of Adomona, Arizona, 47 

Figure 2. Cross bedding in wind blown sand, Rio Puerco 

valley, Andomona, Arizona. 

Photomicrograph of quartzite from Tuscarora formation, 
Jacks Mountain, Mapleton, Pa., Crossed 
nicols, 40 

Figure 1. Sand grains passed through 20 mesh sieve 
and caught on a 28 mesh sieve. Number 
1 sand, Keystone Works, Pennsylvania 
Glass Sand Co., Mapleton, Pa., 56 

Figure 2. Sand grains of same size, Wedron White 
Sand Co., Ottawa, Illinois, No. 1 sand. 

Figure 1. Sand grains passed through a 28 mesh sieve 
and caught on a 35 mesh sieve. Keystone 
No. 1 sand, 56 

Figure 2. Sand grains of same size, Wedron No. 1 

Figure 1. Sand grains passed through a 35 mesh sieve 
caught on a 48 mesh sieve. Keystone No. 1 
sand, 56 

Figure 2. Sand grains of the same size, Wedron No. 1 

Figure 1. Sand grains passed through a 48 mesh sieve 
and caught on a 65 mesh sieve. Keystone 
No. 1 sand, 56 

Figure 2. Sand grams of same size, Wedron No. 1 

Figure 1. Sand grains passed through a 65 mesh sieve 
and caught on a 100 mesh sieve. Keystone 
No. 1 sand, 66 

Figure 2. Sand grains of same size, Wedron No. 1 

Figure 1. Sand grains passed through a 100 mesh sieve 
and caught on a 150 mesh sieve. Keystone 
No. 1 sand , 56 

Figure 2. Sand grains of same size, Wedron No. 1 

Figure 1. Sand grains passed through a 150 mesh sieve 
and caught on a 200 mesh sieve. Keystone 
No. 1 sand, 56 

figure 2. Sand grains of same size, Wedron No. 1 

Figure 1. Sand grain^ passed through a 200 mesh sieve. 

Keystone No. 1 sand , 56 

Figure 2. Sand grains of same size, Wedron No. 1 


Plate XII. 

Plate Xlll. 

Plate XIV. 

Plate XV. 

Plate XVI. 

Plate XVII. 

Plate XVIII. 
Plate XIX. 
Plate XX. 

Plate XXI. 

Plate XXII. 

Plate XXIII. 
Plate XXIV. 
Plate XXV. 


Figure 1. Standard Blake Type Crusher. Built by 

Lewistown Foundry and Machine Co. , . . . . f 7 
Figure 2. Cross section of Blake Type Rock Crusher. 

Built by Phillips and McLaren Co. 

f^igure 1. Standard 8 foot Chaser Mill and screens, as 
built by Lewistown Foundry and Machine 
Co 57 

Figure 2. Eight foot Sand Mill, as built by PhUlips and 
McLaren Company. 

Figure 1. Double Flight Sand Washing Screws, as^ 

built by Phillips and McLaren Company, . . 58 

B'^gure 2. The 18 inch by 12 foot washers, arranged in 
parallel. As manufactured by Lewistown 
Foundry and Machine Co. 

Three batteries of three screws each, arranged in tandem. 
As erected by Phillips and McLaren Com- 
pany, 08 

Figure 1. Cummer Style "F** Dryer, Self-contained, 

exhaust fan , 59 

BHgure 2. Cummer Dryer, semi-self-contained type, with 
disc fan. 

Figure 1. Style "A," Triumph Steel Disintegrator, as 
manufactured by C. O. Bartlett and Snow 
Co., 61 

Figure 2. Cross section of No. 24 Pulverizer, as manu- 
factured by American Pulverizer Company. 

Figure 3. Number 24 Pulverizer, with top removed. 

Water- jet sand washing plant, as manufactured by 

Schulte and Koerting Co. , 62 

Washing sand by water jets to a Number 5 Nye Pump, 

after blasting, ' 63 

Figure 1. Nine foot, iron frame, dry pan, motor driven, 

as built by the Stevenson Company, .... 63 

Figure 2. Nine foot dry pan, pulley driven, as built by 
the American Clay Machinery Co. 

Number 2, type "MM," Single Magnet Separator, as 
built by the Dings Electro- Magnetic Separa- 
tor Co., 64 

Figure 1. One ton Smith Glass Batch Mixer, arranged 
for mechanical handling of batch to and 
from mixer, 96 

Figure 2. Number 117 Smith Glass Batch Mixer discharg- 

Diagram showing how gas, oil and water may occur in 

the same sand , 99 

Map showing distribution of the oil and gas fields in 

western Pennsylvania, 99 

Diagram showing tlie value of Natural Gas produced and 
consumed in Pennsylvania, during the 
period 1900 to 1914, 100 


Plate XXVI. 

Plate XXVII. 
Plate XXVIIl. 

Plate XXIX. 

Plate XXX. 
Plate XXXI. 

Plate XXXII. 

Plate XXXIII. 
Plate yXXIV. 

Plate XXXV. 
Plate XXXVI.. 
Plate XXXVII. 
Plate XXXIX. 

Plate XL. 
Plate XLI. 

Plate XLII. 
Plate XLIII. 

I'jat** XLIV. 
Plate XLV. 
Plate XLVI 

Plate XLVII. 
Plate XLVIII. 

Plate XLIX. 
Plate L. 


Diagram showing the amount of Natural Gas produced 
and consumed in Pennsylvania during the 
period 1906 to 1914. 100 

Cross section of Bradley Gas Producer, 101 

Figure 1. Ckml hopper for charging producers 103 

Figure 2. Steam jet blower. 

Figure 1. Bradley hand poked gas producer, installed, 104 
Figure 2. Duff gas producer (Elevation and section 
through neck.) 

Hughes Producer (Standard type) , 104 

Mechanically stirred producer, as built by R. D. Wood 

and Company , 105 

Map of Pennsylvania, lowing distribution of coals by 

fuel ratios, 105 

Different styles of glass pots , Ill 

Figure 1. Building glass pots, 113 

Figure 2. Various sises and ^apes of tank blocks. 

Section through a regenerative pot furnace, 114 

A regenerative pot furnace, Ill 

Jlorizontal section of a continuous glass tank , 117 

Cross section of a typical producer gas glass tank, .... 117 

Figure 1. Two piece floaters, 118 

Figure 2. Three piece keyed floaters. 

Side port tank furnace, with crane filling shovel 120 

Figure 1. Lehr fronts, 127 

Figure 2. Endless carrier for lehrs. 

End port tank furnace, 120 

Figure 1. Semi-automatic pressing and blowing madiine 

for narrow neck bottles, 130 

Figure 2. Semi-automatic pressing and blowing madiine 
for wide mouth bottles. 

Figure 3. Pressing and blowing machine for milk jars and 
wide mouth ware. 

Owens automatic gathering and blowing machine, 130 

Sectional diagrams showing evolution of a tumbler, . . . 134 

Figure 1. Blowing and moulding lantern globes, 134 

Figure 2. Pressing a bowl. 
Figure 3. Hand presses. 

Sectional diagrams showing evolution of a cylinder of 

window glass, 137 

Figure 1. Forming the dap of a cylinder of window glass, 137 
Figure 2. Blowing the cylinders. 
Figure 3. Cracking open the cylinders. 

The Colburn Window Glass Drawing Machine and An- 
nealing Lehr, 139 

Figure 1. Casting table (H. L. Dixon Co.) , 140 

Figure 2. Electrically driven glass casting machine for 

rolling ribbed or figured glass (Rosedale 

Foundry and Machine Co.) 


Plate LI. 
Plate LII. 

Plate LIII. 
Plate UV. 
Plate LV. 

IMate LVI. 

I'late LVII. 

Plate LVIIL 

Plate LIX. 

Plate LX. 

Plate LXI. 

Plate LXll. 


Figure 1. Casting plate glass, 141 

Figure 2. View in a glass grinding and polishing plant. 

Diagram showing value of glass production of seven lead- 
ing states compiled from United States 
Census Reports, 147 

Photomicrograph of a thin section of calcareous Oriskany 

sandstone from Kingston, N. Y., 153 

Paleogeography of the Eastern United States during 

Oriskany time, 150 

Figure 1. Photomicrograph of a thin section of bluish 
gray quartzite from North Quarry of West- 
brook Glass Sand Company, Mill Creek, 
Pa., 163 

Figure 2. Photomicrograph of a thin section of sandstone 
stained by limonite, Juniata White Sand 
Company's Quarry. Looking southwest, 
Mapleton, Pa. 

Working face of North Quarry of Pittsburgh White 
Sand Company, looking southwest, Maple- 
ton, Pa., 167 

Figure 1. Cross section of North Quarry of Westbrook 

Glass Sand Company, Mill Creek, iPa., .. 168 

Figure 2. Looking northeast in North Quarry of the 
Westbrook Glass Sand Company, Mill 
Creek, Pa. 

Figure 1. Cross section of syndine at Granville mine of 
Pennsylvania Glass Sand Company, south- 
west of Lewistown, showing position of 
Oriskany outcrop , 169 

Figur^ 2. Cross section of syndine at old Macklin mine, 
McVeytown, showing position of Oriskany 

Figure 1. Cross section of Sandy Ridge north of North 
Quarry of Keystone Works of Pennsyl- 
vania Glass Sand Company, Mapleton, Pa., 170 

Figure 2. Looking northeast from Mapleton Quarry of 
the Pennsylvania Glass Sand Company, 
Mapleton , Pa. 

Outcrop of Oriskany sandstone north of Keystone Works 
of the Pennsylvania Glass Sand Company, 
Mapleton, Pa., 171 

Near view of a portion of the outcrop of the Oriskany 
sandstone north of the Keystone Works of 
the Pennsylvania Glass Sand Company, 
Mapleton , Pa. , 174 

Figures 1 and 2. Near views of portions of the outcrop 
of Oriskany north of the Keystone Works 
of the Pennsylvania Glass Sand Company, 
Mapleton, Pa., 174 

Figure 3. Pulpit rocks along Huntingdon-Alexandria 
road, northwest of Huntingdon, Pa. 

Plate liXIII. 
riate LXIV. 

I'late LXV. 

Plate LXVI. 

Plate LXVII. 

mate LXVIII. 

mate LXIX. 

I'late LXX. 

I'late LXXI. 

liate liXII. 

Plate LXIII. 
Plate LXXIV. 

Plate LXXV. 
Plate LXXVI. 

Plate liXXVII. 



Pulpit rocks along Hantingdon- Alexandria road, north- 
west of Huntingdon , Pa., 174 

Gross section showing structure of the formation under- 
lying Huntingdon County, 177 

Map showing Oriskany outcrops in Huntingdon, Mifflin 

and portion of Bedford counties, 178 

Map showing location of glass sand quarries in the 

vicinity of Mapleton , 178 

Figure 1. Gross section of Sand Ridge one quarter mile 
south of South Quarry of Pittsburgh Wliite 
Sand Gompany, Mapleton, Pa., 183 

Figure 2. Gross section of Sand Ridge 3 miles north of 
Saltillo, Pa. 

Sand Ridge in the vicinity of the Keystone Works of 
the Pennsylvania Glass Sand Gompany, 
north of Mapleton, Pa., 184 

Portion of the northeast working face at the North 
Quarry of the Keystone Works of the 
Pennsylvania Glass Sand Gompany, at 
Mapleton , Pa. , 185 

Figure 1. Iiooking northeast in the South Quarry of the 
Golumbia Works of the Pennsylvania Glass 
Sand Go., at Mapleton, Pa., 186 

Figure 2. Looking southwest in the abandoned quarry of 
the dismantled Franklin Works of the Penn- 
sylvania Glass Sand Go., at Mapleton, Pa. 

Figure 1. Gross section of Sand Ridge, 3} miles north of 

MiU Greek, Pa., 188 

2. Abandoned quarry in Oriskany sandstone at Mc- 
GonneUtown, Pa. 

Figure 1. View in quarry of Standard Sand Gompany 
at Brumbaugh's Siding, south of McGon- 
nelltown. Pa. , 190 

Figure 2. View in quarry on farm of H. B. Brenneman, 
Marklesburg, Pa. 

Flow sheet of Mapleton Works of the Pennsylvania 

Glass Sand Gompany, Mapleton, Pa., ... 194 

Figure 1. Mapleton Works of the Pennsylvania Glass 

Sand Gompany, Mapleton, Pa., 194 

Figure 2. Keystone Works of the Pennsylvania Glass 
Sand Gompany, Mapleton, Pa. 

Flow sheet of the Keystone Works of the Pennsylvania 

Glass Sand Gompany, Mapleton, Pa., .... 195 

Figure 1. Keystone No. 1 sand as it appears under the 

miscroscope, 196 

Figure 2. Working face at North Quarry of Golumbia 
Works of the Pennsylvania Glass Sand 
Gompany, Mapleton, Pa. 

Flow sheet of the Golumbia Works of the Pennsylvania 

Glass Sand Gompany, Mapleton, Pa., .... 197 




Plate I/XXVIII. 

Plate LXXXIX. 
Plate LXXX. 
Plate LXXXI. 
Plate LXXXII. 
Plate LXXXI II. 

IMati' LXXXI V. 

Plate LXXXV. 

Plate LXXXVI. 



Plate LXXXIX. 
Plate XC. 

Plate XCI. 
Plate XCII. 


Figure 1. View in North Quarry of Pittsburgh White 
Sand Company Ijooking northeast, Maple- 
ton, Pa., 197 

Figure 2. View of quarry of Hummel Sand Company at 
Hummel Station, Pa. 

Flow sheet of North Plant of Pittsburgh White Sand 

Company , Mapleton , Pa. , 199 

Flow sheet of South Plant of Pittsburgh White Sand 

Company, Mapleton , Pa., 199 

Flow sheet of plant of Juniata White Sand Company, 

Mapleton, Pa., 20O 

Geologic cross section of Mifflin County in the vicinity 

of McVeytown, Pa. , 2(KJ 

Figure 1. Cross section of the ridge northeast of Bum- 
ham, Pa., at John Miller's Sand Mine, 
showing position of the Oriskany sandstone 
with respect to the surface, 2(H 

Figure 2. Similar section at the sand pit of the Standard 
Ste^l Company. 

Figure 3. View in the sand pit of the Standard Steel 
Company northeast of Bumham, Pa. 

Figure 1. Near view of the Oriskany sandstone in Hat- 
field Quarry of the Pennsylvania Glass 
Sand Company at Vineyard, Pa., 209 

Figure 2. Hatfield Works of the Pennsylvania Glass 
Sand Company at Vineyard, Pa. 

Diagram showing method of mining employed at Juniata 
Mine of Pennsylvania Glass Sand Com- 
pany at Granville, Pa. , 211 

Flow sheet of Juniata Works of the Pennsylvania Glass 

Sand Company at Granville, Pa., 215 

Flow sheet of Hatfield Works of the Pennsylvania Glass 

Sand Company at Vineyard, Pa., 216 

Figure 1. View in Enterprise Quarry of the Pennsylvania 
Glass Sand Company, looking northeast, 
Vineyard, Pa., 217 

Figure 2. View in central portion of above quarry. 

Figure 3. View looking southeast in above quarry. 

Flow sheet of the Enterprise Works of the Pennsylvania 

Glass Sand Company at Vineyard, Pa., .. 217 

Figure 1. View in quarry of Crystal Sand Company, 

Vineyard, Pa 217 

Figure 2. View in quarry of Calvin Ritchey, TatesviUe, 
Pa. Looking north. 

Flow sheet of Crystal Sand Company Plant, Vineyard, 

Pa., 217 

Figure 1. Diagram of old quaory of BHtzpatrick Glass 

Company, Falls Creek, Pa., 240 

Figure 2. View in quarry of Fox Silica Sand and Stone 
Company, Daguscahonda, Pa. 



Plate XCIII. Flow sheet of Fox Silica Sand and Stone Company, 

Daguscahonda, Pa., , 241 

I'late XCIV. Figure 1. View in quarry of Ridgway Sand and Stone 

Company, Ridgway, Pa 241 

Figure 2. View in quarry of Ridgway-Croyland Silica 
Sand Company, Garovi, Pa. 

Plate XCV. View in quarry of Dunbar Furnace Company, Dunbar, 

Pa 245 

Plate XCVI. Plant of the Spring Creek Glass Sand Company at 

Straight, Pa., 248 

Plate XCVII. Flow sheet of the Spring Creek Glass Sand Company's 

plant at Straight, Pa., 249 

Plate XCVIII. Figure 1. Diagram of Pittsburgh Plate Glass Company's 

quarry at Kennerdell, Pa., 253 

Figure 2. View in main portion of above quarry. 

Plate XCIX. Figure 1. Working face at southeast end of Pittsburgh 

Plate Glass Company's quarry at Kenner- 

deU, Pa., 253 

Figure 2. Glass sand plant of Pittsburgh Plate Glass 
Company at Kennerdell, Pa. 

Plate C. Flow sheet of glass sand plant of Pittsburgh Plate Glass 

Company at Kennerdell , Pa. , 253 

l*late CI. Figure 1. Diagram of working face at quarry of Warren 

Silica Company, Torpedo, Pa., . . rs 256 

Figure 2. View in above quarry. 

Plate CII. Plant of Warren Silica Company, Torpedo, Pa., 250 

Plate CIII. Flow sheet of Warren Silica Company's plant. Torpedo, 

Pa., 257 

Plate CIV. Figure 1. Diagram of glass sand quarry at American 

Window Glass Company at Derry, Pa., .. 259 
Figure 2. View in above quarry. 

Plate CV. Flow sheet of glass sand plant of American Window Glass 

Company at Derry, Pa. , 259 

I*late CVI. Figure 1. View in old quarry of Derry Glass Sand Com- 
pany at Derry, Pa., 260 

Figure 2. Plant of Derry Glass Sand Company at Derry, 
* ' . y Pa- 

Plate CVII. W • / -, -»t^ iheet of plant of Derry Glass Sand Company at 

' Derry, Pa., 260 

Plate CVIII. Map of Pennsylvania showing location of glass sand 

quarries and glass factories in pocket. 






Glass sands are sands that are almost entirely made up of quartz 
grains, founid in nature either in the form of loose, unconsolidated 
sediments, or in deposits in which the individual grains are iQore 
or less thoroughly bound together by some cementing agent. Such 
sands are now used almost exclusively in the manufacture of glass 
as the source of the silica which is the major constituent of this 
useful substance. While deposits of sands and sandstones occur both 
widely and abundantly in nature, deposits that are sufficiently free 
from other constituents than quartz grains, so that they can be 
employed in the manufacture of glass, especially of the better grades, 
are, comparatively speaking, of rare occurance. 

Pennsylvania holds a leading position among the states of the 
Union in the production of this grade of sanid as weU as in the 
manufacture of the various kinds of glass products into which it 
enters. It was, therefore, thought a description of the glass sand 
deposits would be of interest and of value to the citizens of Penn- 
oylvania. In connection with the preparation of such an account 
the necessary qualifications of glass sands for different kinds 
of glass were also investigated, as well as the methods of manu- 
facture of the different glass products, since many difficulties en- 
countered which are charged by the manufacturer to the sand used, 
may often be traceld to some other source. For this reason a brief 
description of all materials used and the methods of manufacture 
employed are also incorporated in this report. 

The preparation of this report was undertaken for the Topographic 
and Geologic survey Commission of Pennsylvania, under the super- 
vision of Richard R. Hice, the State Geologist. The chemical and 
screen analyses and petrographic examinations of the san^ were 
performed in the geological and mineralogical laboratories of the 
Carnegie Institute of Technology of Pittsburgh. For assistance 
lendered in carrying on the work the writer wishes £o express his 
thanks to the owners and officers of the various Companies pro- 
ducing glass sand in the State, who practically without exception 




.allowed him entire freedom in examining tiieir plants and quarries 
and furnished him with all the information desired in regard to 
their operation. Especial thanks are due to W. P. Stevenson, of Mc- 
Veytown, for an account of the early history of the glass sand in- 
dustry in Mifflin county. The writer also wishes to thank the officers 
of the Thomas Carlins Sons Co., the Lewistown Foundry and Ma- 
chine Co. and the Phillips and McLaren Co., for data in regard to 
the cost of machinery and other equipment used in connection with 
sand plants; to Geo. W. Cochran of the Ohio Valley Clay Pot Co., 
H. A. Eatherton of the Findlay Clay Pot Co., Chas. O. Grafton of 
the Gill Clay Pot Co., J. G. Quay of the Beaver Vallqr Pot Co., and 
A. S. Zoppi of the Buckeye Clay Pot Co., for information in regard 
to the manufacture of clay pots; and the officers of the American 
Window Glass Co., the Fidelity Glass Co., the H. C. Fry Glass Co^ 
the Hazel-Atlas Glass Co., the Jeanette Glass Co., the McKee Glass 
Co., the Pittfi/burgh Plate Glass Co., and the Tarentum Glass Co., for 
permission to inspect their plants. Dr. S. R. Scholes, of the Mellon 
Institute of the University of Pittsburgh, also furnished the writer 
with valuable information in regard to the properties necessary for 
glass sands used in the manufacture of flint glass and the methods 
employed in the manufacture of glass pots. 

The examination of the various glass sand quarries in the State 
of Pennsylvania upon which this report is based were made during 
the summer and fall of 1914« 




It is a paiher difficult matter to give a definition of glass that will 
hold gooid for all cases. For example, if one takes such a property 
as transparency, which the term glass at once suggests, one findh 
that while most glasses possess it, there are a number which do not, 
some are not even translucent, and yet they are true glasses. The 
same holds true for any of the characteristics of glass. There is, 
however, one property which all substances that may be classified a« 
glass possess in common, that is an amorphous structure. 

By amorphous structure is meant an entire absence of any mole- 
cular arrangement in a particular substance. This distinguishes 
glasses from most mineral and other inorganic bodies, which on solid- 
ifying usually take on a definite molecular or crystalline structure, 
which gives them certain optical and other physical properties, 
characteristic for each substance. These properties will usually vary 
along different directions in the same substance. For example, in 
the case of a crystal of quartz a ray of light travelling through it 
in the direction of the vertical axis will behave differently from one 
passing through it at right angles to that axis, due to the nature 
of the internal structure of the crystal. In the case of a piece of 
glass light will be transmitted through it in the same manner in 
all directions. This is due to the fact that there is an entire absence 
of any structure which would affect the ray ^differently in different 
directions. Liquids and colloid bodies also show this same indefinite 
arrangement of their molecules. 

There is still another characteristic which also emphasizes the 
close relationship between glass and ordinary liquids. When a 
glass is cooled from the molten or liquid condition it gradually be- 
comes more and more viscous until finally the solid state is reached. 
At no particular stage in this process is there a definite amount 
of heat liberated, the loss of heat being an entirely uniform one 
from start to finish. In the case of crystalline substances, however, 
this is not true, for when they are cooled from their liquid state 
a certain tPinporatnro will be reached at which a definite amount 
of heat will be released, and the temperature instead of dropping 
uniformly will remain stationary for a time, until the solid state 
has been assumed. It is at this point that the crystalline struc- / 

ture is taken by the molecules. This is accomplished by the libera- 
tion of energy in the form of heat. In contrast, therefore, to the 


crystalline structure of true solids, glasses may be considered to be 
highly viscous or congealed liquids. 

The chemical composition of glasses as a rule is a rather complex 
one. In most cases it consists of one or more anhydrides or acidic 
oxides, in combination with several basic oxides. In the ordinary 
glasses of commerce silica (SiO.^) is the anhydride present, while 
sodium oxide (Na20), lime (CaO), potassium oxide (KjO) and lead 
oxide (PbO) are the most common basic oxides. In addition to 
these, however, several other acidic oxides, such as boron trioxide 
(B2O3) and phosphoric anhydride (PgOg), and a large number of 
other basic oxides besides those mentioned above, enter into the 
composition of certain^ special glasses, such as those used for optical 
purposes and in chemical laboratories. The various compounds 
formed by the combination of these oxides are present in the glass in 
Folution in one another, for, as has been before stated, glasses may 
be regailded as being simply rigid solutions. 

One other distinction besides that of amorphous structure must be 
made to distinguish glasses from such products of the clay industry 
as porcelain, which, so far as their outer appearance are concerned, 
resemble certain glasses very closely. In the case of the glasses it is 
necessary that the materials which go to make up the final product 
are first brought to the molten condition by fusion, and then allowed 
to assume the solid form by cooling, being given their desired shape 
\^ hile still plastic. In the case of porcelain, or other clay wares, 
the raw materials are mixed with water to a paste and this paste 
h molded into the desired form while cold. It is then heateU to a 
high temperature to harden it, but not suflSciently high to fuse it. 

The following analyses will illustrate the chemical composition of 
some of the more common kinds of glass: 


Window Glass. 







































1 1 
(4) 1 (4) (1) 

1 ' 





AlaOs. — 
FeaOs, — 

1 1.42 

1 to 2 





( 1.4 

72.5 1 00.05 
l.CO \ 1.82 

.4 ) 








Na«0. — 






13.1 1 13.81 
13.0 1 15.22 










100.0 , 100.00 




'Including MnOt. 


Plate Glasfl. 








Total. . 

























) 1.0 

1.0 to 8.0 































Plate GXaxjS — Goiitinned. 








Total. . 


























Lime Flint Glass. 

















j .44 






1 tract 























Bottle Glass. 




















1 2.68 


y 7.96 

^ ,:« 








































*Not reported. 

Lead Flint Glass. 





Na«6. "Zilllllinill-IIIIII 

pbo*. miiiiiiiiiziiiiiiiiiii 






I .90 


1 liTso' 


j 1.12 

J .70 

} 7.80 








(1). Qlau. Robert Linton, Mineral Industry for 1890, Vol. 8, pp. S84-208. 

(2). Olasi. Sir Edward Tborpe. Dictionary of Applied Ohemlatry, Vol. 2, pp. 710-789. (1012). 

(8). The Requirements of Glass for Bottling Purposes. R. L. Frlnk. Trans. American 

Oeramie Society, Vol. 15 (1918), pp. 700-727. 
(4). The Commoner and Glass Worker, Vol. 21 (1890, No. 11. Quoting from EngUah Piottarj 

Gazette . 
(6). Handbuch der Glasfabrikation, Fifth Edition, Dr. E. TKbeuschner, Welmer, 1885. 
(0). Die Glasfabrikation. Second Edition. Raimund Gemer, Vienna, 1897. 
(7). Glass. James Gillinder. Industrial Obemlstry, edited by Allen Rogers and Alfred B. 

Aubert. New York, 1918, pp. 813-828. 

An inspection of the foregoing analyses shows there may be con- 
siderable variation in the chemical composition, even in the case 
of glasses used for the same purpose, and yet all of them will possess 
the properties necessary for that particular use. This is true of all 
the ordinary varieties of glass, such as window, plate, bottle, lime 
flint and lead flint for tableware, but does not hold good in the case 
of special glasses, such as those used for optical purposes, where 
small variations in chemical comjK)sition are often accompanied by 
considerable differences in optical properties. In the manufacture 
of this kind of gla.*5s, therefore, great care must l)e exercised to obtain 
the proper composition. 

Even in the case of the ordinary glasses of commerce, however, 
although a certain amount of variation in composition is permissable, 


there are certain limits to which these variations in the molecular 
ratios or proportions of the various oxides composing the glass must 
be confined, or the glass will not show the necessary resistance to 
the action of the air, moisture, acids or other decomposing agents, 
and will 'be deficient in other physical and chemical properties. The 
molecular ratios of the various oxides are obtained by dividing the 
percentage composition of each oxide by its molecular weight. 

From a comparison of the analyses of a large number of different 
samples of glass Tscheuschner derived the following formula for the 
best or "normal glass": 


x R% O, y R" O, ;q — + y |SiO, 

In this formula R*2^ represents the sum of all the molecular ratios 
of the alkalies present in the glass, namely NagO and KjO, while the 
R"0 represents that of the alkaline earths, CaO, MgO and BaO, 
and the metallic oxides sometimes present such as PhO, ZnO and 
FejOg. In the case of AlgOg there is still some doubt as to whether 
it plays the part of a metallic or an acidic oxide in the glass. 
Dralle claims that satisfactory results may be obtained by classing 
it with the silica in the above formula, even when the percentage of 
AljOj present is fairly large. X represents the coefficient obtained by 
adding the molecular ratios of the alkalies, while y represents the 
one obtained by adding those of the alkaline earths and other 
metallic oxides present. The coefficients x and y must fall within 
certain limits in order to give the glass the necessary properties to 
make it desirable. According to Dralle a good lime-soda glass will be 
obtained if when the coefficient y is made equal to 1.0, x falls between 
0.5 and 1.0 and the coefficient of SiOg is equal to 3(x^+l)- 

For window glass Tscheuschner states that x can vary between 
0.6 and 1.0 when y is made equal to 1.0, and for lime flint between 
0.8 and 1.5 and give good results. In the case of the potash glasses 
more silica should be used, so that insteaid of 3(x'-|-l) the coefficient 
of SiOj should be ^(x^+l). 

The alkali glasses melt more readily than those high in lime, but 
the latter are cheaper. The above formulas can also be used for 
lead glasses, but on account of their greater fluidity, the Amount 
of silica specified by the above formulas may be exceeded. Like- 
wise lead glasses very low in alkalies may be made, which are very 
durable on account of the slight solubility of the lead silicate formed. 

Gelstharp and Parkinson have carried out a number of interesting 
experiments which have enabled them to prepare a triaxial dia- 
gram in which the approximate practical limits of variations in 
composition for lime-soda glasses are shown, especially those used 


in the manufacture of plate glass, but also applicable to t)ottle glass, 
table ware and winklow glass, where lime, soda and silica are the 
principal constituents present, and other oxides, such as those of 
potassium, magnesium, barium, zinc, lead, manganese, iron, aluminum 
and bOron are practically absent. This diagram is reproduced in 
Plate I. 

Below the line joining 2Na20.S102 and CaO.SiO, basic slags and 
infusible mixtures of silicates and bases are formed. Between this 
line and the one joining Na^CSiOa and 2Ca0.3Si02 transparent 
glasses are formed only on very rapid cooling, otherwise only opaque 
crystalline masses result. Between the latter line and the one j6in- 
ing NajO-SSiOg and 2Ca0.3Si02 transparent glasses proper, including 
those of technical importance appear, while above this area only 
opalescent opaque glasses result on slow cooling. In the area repre- 
senting the composition of the transparent glasses, the good mechan- 
ically strong and durable ones may be separated by a line on the 
left cutting off those containing sodium in excess of 22% of the silica 
content, and below by a line joining Na20.2Si02 and Ca0.2SiO,. 
Below this latter line the glasses formed are, for the most part, 
mechanically weak, have not sufficient resistance to withstand the 
action of dilute acids, water or the atmosphere and tend to devitrify 
or crystalize readily. The desirable glasses formed are rep- 
resented by the shaded portion of the diagram. It is divided 
into two parts by a line drawn from the apex of the triangle te a 
point which represents a molecular ratio of soda to lime of 2 to 1. 
Only in the small jK)rtion to the left can soda ash (NajCO,) alone be 
the source of the alkali. In the portion to the right of this line, 
according to Qelstharp and Parkinson, salt cake (NajSO^) must be 
used, at least in part, or white scum and flakes will be produced. 

In the diagram, in order to determine the percetange composition 
of any glass, such as one represented by the point "A," measure off 
the distance A-b to the 10% line for NagO, using the scale of the 
diagram, to get the percentage of NaaO. In a similar manner measure 
off the distance Ac to the 10% line for CaO, to get the CaO percent- 
age and the distance A-d to the 70% line for SiOj to get the SiOj per- 
centage. In the above case the results are 18.8% CaO, 13.2% NajO 
and 73.0% SiOj. If the percentage composition of a lime-soda glass 
is known its jK)sition on tne diagram may be found by reversing the 
operation as above outlined. 









In as much as there are a large number of different substances 
available for supplying the acid and basic oxides in glass, and no 
definite proportions are necessarj% but the relative amounts may vary 
considerably and still give glasses of technical value, a wide range of 
glasses is possible. On examination, however, it will be found that 
the great majority of those actually used will belong to one or another 
of a few main types. 

A great many different classifications of glasses have been proposed, 
based on different factors, such as chemical composition, technical 
use, method of manufacture, etc. On the following pages several of 
these are given. The first one is based chiefly on chemical composi- 
tion, the second two on technical use, and the last one on method of 

Thorpe's Classification of Glasses.^ 

A. Glasses In which the add Is entirely silica, combined with two or more 

bases, one of which is an alkali. 

1. LIrae-Sodu Glass.— This type is very extensively employed for win- 

dow glass, chemical glassware, bottles, etc. The precise composi- 
tion varies in different cases. CaO is sometimes partially replaced 
by BaO, and a small amount of alumina Is generally present. 

2. Alumina-Lime-Soda Glass.— This Is chiefly used for beer, wine and 

spirit bottles, owing to its strength and Insolubility. 

3. Lime-Potash Glass.— Generally known as Bohemian glass. Used for 

hollow ware. 

4. Lead-Potash Glass, Lead Flint.— Used extensively in the manufac- 

ture of hollow ware, Ijottles and optical glass. 

B. Glass containing other acids in addition to silica. 

1. Boro-Sllicate Crown.— Like type A-1 above, with silica partially re- 

placed by B-Oa. Used for optical glass, thermometer tubing, and 
laboratory ware. 

2. Boro-Sllicate Flint.— Like type A-4 above, with silica partially re- 

f)laced by BaOs. Used for optical glass, in the manufacture of 
enamels, "strass" for imitation gems, etc, 

3. Phosphor Glass.— In which the silicon is partially replaced by phos- 


0. Glass containing no silicon: "Borate" and "phosphate" glasses. Occasion- 

ally used in optical work. 

D. Simple silicfites consisting of silica and alkali only. This type is soluble 

In water, and is known as soluble or water glass. 

E. Quartz glass, consisting of pure silica In the amorphous state. 

Knapp's Technical Classification." 

1. Lead Free Glasses. 

A. Bottle glass with its varieties. 

a. Common bottle glass, composed of SiOa, a little AlsOa. and 

FciO., OaO, and NasO. 

b. Glass for druggists' bottles, made of the same materials, though 

usually with only a very little AhOs and FcaOa. 

c. White bottle glass, for bottles, drinking glasses, tubes, etc., 

made of SlOa, CaO, and NaaO or KaO, usually the former. 

B. Window glass, composed of SiOi, a very little AUOa, CaO, NaaO. and 

very rarely some KaO. 
O. Plate glass, made of SiOi, a very little AlaOa, CaO, NaaO. or very 
rarely KaO. Distinguished from window glasp by the fact it is more 
nearly colorless. 

1. Glass, Dictionary of Applied ChemlBtry, by Sir Edward Thorpe, Vol. 2., (1012) pp. 710-780- 

2. Handbuch dcr glass labrlkatlon by Dr. ©. O^jheuschnar, 6th edition. Weimar, 1886. 


IL Qlasses containing lead. 

D. Orystal glass, for cut glass, made of SiOt, PbO. and KiO. 
£. Flint glass (most of the optical glasses), made of SiOa or BtOs, or 
both, more PbO than the crystal glass, and KiO. 

F. Flint glass (most of the imitation gems), made of SiOt, a greater 

lead content than either D or £, and KaO, colored with different 
metallic oxides. 

G. Enamels, made of SiOt, PbO and NasO. Rendered opaque with ZnO 

or Sb.Ot. 

Linton*s Commercial Classificatiou.s 

1. Polished plate.— Embraces all glass cast upon a smooth table, rolled to 

the required thickness with a roller, annealed, and then ground and 

2. Rough Plate.— Embraces all glass cast as above, but not ground and 

polished. The principal varieties are ribbed plate, colored cathedral, 
rough plate, wire glass and heavy rough plate for skylights. 
). Window Glass.— Embraces glass blown in cylinders, and afterwards cut, 
flattened out and polished while hot. Ohieflly used for glazing, pic- 
tures, mirrors, etc. 

4. Crown Glass.— Embraces glass blown in spherical form and flattened to a 

disk shape by centrifugal motion of blow pipe. A little is made at the 
present time for decorative purposes. 

5. Green Glass.— Embraces all the common kinds of glass, and is not neces- 

sarily green in color. It is used in the manufacture of bottles, carboys, 
fruit jars, etc. 

6. Lime Flint.— Embraces the finer grades of bottles used for the prescription 

trade, tumblers, certain lines of pressed table ware, and many novelties. 

7. Lead Flint.— Embraces all the flncst products of glass making, such as fljie 

cut glass, table ware, optical glass, artificial gems, etc. 

Benrath's Classification, According to Method of Manufacture.* 

1. Glasses which are cooled rapidly and which are not given any definite 

shape, as water glass, smalt, and fritts. 

2. Glasses which are only worked after very slow cooling and complete solidifi- 

cation, such as optical glass and artificial gems. 

3. Glasses which are cooled moderately and in a still semi-fiuld, viscous state 

are given their shape. Green glass or bottle glass, semi-white hollow 
glass ware, white hollow glass ware, tumbler glass, turbid and colored 
tumbler glass, milk or opal glass, cryolite glass, colored glass, lead 
crystal, tubes and bead glass, and sheet or window glass. 

4. Glasses in whose formation the more fiuid condition of the glass at a higher 

temperate is made use of. such as rolled and pressed glass. 

3. Glau. by Robert Linton. Tlie lOnenU Indostry for 1890, Vol. Vm, New York, 1900, pp. 


4. Handbuch der glass fabrflcation by Dr. E, fTsobeaschiier. 6tb edition, Weimar. 1886. 




It has already been shown that glass may be considered as a con- 
gealed solution of a number of chemical compounds, usually silicates 
of various metallic elements, in one another. The bases most com- 
monly employed are the alkalies, sodium and potassium, the alkaline 
earths, calcium, magnesium, barium, and rarely strontium, and the 
oxides of lead and in minor quantities of alumina and iron, the latter 
two being usually present as impurities in some of the ingredients 
.used in the manufacture of glass. Many other metallic oxides in 
addition to those enumberated above are occasionally used to impart 
special properties to the glass. The acid radical usually consists of 
silica, but in some special glasses the boric and phosphoric acid 
radicals are also' employed to replace the silica, in whole or in part. 
Inasmuch as the chemical composition plays an important part in 
determining both the chemical and the physical properties of the 
resulting glass, with this wide range in possible ingredients a great 
many different types of glasses may be produced. 

Although molten glass if cooled sufficiently rapidly takes on an 
amorphous structure, during this cooling a certain point will be 
reached where there will be a tendency for certain of the constituents 
to crystallize out. If crystallization actually takes place, it is known 
as devitrification. 

The facility with which this crystallization will occur depends 
largely upon the chemical composition of the glass. In some cases 
it sets in so readily that it is almost impossible to prevent it, while 
in other cases the glass must be kept at the proper temperature for 
hours before any crystallization can be induced. 

As the glass is cooled below the temperature at which devitrifica- 
tion tends to take place the liquid becomes more and more viscous 
and the tendency of the molecules to arrange themselves in a definite 
crystalline structure is not sufficient to overcome the resistance which 
the liquid presents and an amorphous structure results. 

There exists then a critical range in temperature for every glass 
through which the crystallizing forces have the greatest tendency to 
overcome the internal resistance of the glass and if the glass is not 
cooled sufficiently rapid devitrification sets in at this point. Below 
this temperature this tendency becomes less and less marked, until 
at ordinary temperatures the internal resistance prevents it entirely. 

As has already been stated the chemical composition plays an im- 
portant role in devitrification, glasses of certain compositions tending 
to devitrify much more readily than others. This tendency, thereforr 
places a limit on the range of substances and their relative pi 



portions which can be employed under the conditions ordinarily 
met with in the manufacture of glass. This subject will be discussed 
somewhat further under the various ingredients employed in the 
manufacture. Among other things excess of lime in the glass in- 
creases its tendency to devitrify. Alumina, on the other hand, when 
present in small quantities tends to prevent it. 

Most glasses are exceedingly stable and chemically inert at ordinary 
temperatures, which is an important pfoperty in determing their 
use for many purposes. None of them are, however, by any means 
perfect in this respect. The degree of stability depends largely upon 
the composition of the glass. 

The resistance of glass to atmospheric influence is a matter of 
great importance in the case of window, plate and other glasses ex- 
posed to its attack. This action is a very complex one involving 
attack by water, carbon dioxide, and other gasses and vapors often 
present in the atmosphere, combined with constant variation in 

Pure water will attack all glass to a certain extent by dissolving 
some of the alkali present, but in the cold the action is practically 
negligible except in the case of very poor glass. With rise in tem- 
perature, however, this action increases. Superheated water, that is 
water under steam pressure, is a very active corroding agent, and even 
the best glasses can only resist its action for a limited time. For the 
guage glasses of steam boilers, therefore, especially durable glasses 
are required. In the case of certain glasses this action is not con- 
fined to the surface, but the water penetrates into the mass of the 
glass and combines with it, probably forming hydrates with some of 
the silicates present. This action sometimes takes place where a 
poor grade of glass is stored in a damp place for a considerable length 
of time. 

Alkaline solutions attack glass much more readily than pure 
water. They first combine with the silica of the glass, thus setting 
free the bases, which are carried away in solution. In this way a 
fresh surface of glass is exposed to attack. 

The ordinary dilute acids on the other hand, with the exception of 
hydrofluoric, have relatively little action on glass, much less than 
pure water. The strong acids also, with the same exceptions, have 
practically no action on the silicate glasses. Where boric or phos- 
phoric acid replaces part of the silica, however, this does not hold 
true. Hydrofluoric acid rapidly decomposes all types of glasses by 
combining with the silica to form volatile fluorides. Highly basic 
glasses are less readily attacked than those rich in silica. The action 
on an ordinary lime-soda glass is sho'.vn by the following equations: 



On account of this property, hydrofluoric acid is used extensively 
in etching glass in the decoration of hollow ware. 

Carbon dioxide, a gas which is always present in small quantities 
in the atmosphere, is also instrumental in decomposing glass, es- 
pecially in the presence of moisture. The action is probably a more 
or less indirect one. Some of the water vapor in the atmosphere 
condensing on the surface of the glass as a thin fllm of moisture, 
exerts its dissolving action and a certain amount of alkali is ex- 
tracted from the glass in the form of the hydroxide. Carbon dioxide 
is readily absorbed by this alkaline solution and the carbonate, either 
of sodium or potassium, depending on the composition of the glass, is 
formed. If the moisture evaporates again in the case of soda glass 
a thin coating of minute sodium carbonate crystals will remain be- 
hind on the surface of the glass giving it a dull, dimmed appearance. 
These may be removed by washing, the silica set free by the reaction 
being removed at the same time mechanically. Potassium carbonate, 
en the other hand attracts moisture so readily from the atmosphere 
that it would not under ordinary conditions crystallize out in the dry, 
solid state, and therefore a potash glass would not be as liable to 
exhibit this dim surface, although it would be attacked just as readily 
as a soda glass. 

Bosenhain also calls attention to the fact that the films of alkaline 
solution which are formed on the surface of the glass, especially the 
less resistant varieties, form a ready breeding ground for certain 
kinds of bacteria and fungi, whose growth occurs partly at the ex- 
pense of the glass itself. Specks of organic dust falling upon the 
glass give rise to local decomposition probably for the same reason. 
It has been noticed that the presence of small proportions of boric 
acid in some glasses renders them more resistant to attack from 
atmospheric agencies and much less sensitive to the effects of organic 
dust particles lying upon their surface. This may be due to the fact 
that small quantities of boric acid entering into solution in the film 
of surface moisture exert an anticeptic action which prevents the 
activity of bacterial and fungoid growth. 

Numerous efforts have been made to devise satisfactory means for 
determining the relative resistance of a glass to atmospheric agencies 
without actually awaiting the results of experience through a long 
interval of time. One of the earliest of those proposed consists in 
exposing the surface of the glass to the vapour of hydrochloric acid. 
For this purpose some concentrated hydrochloric acid is placed in a 
glass or porcelain basin and strips of the glass to be tested are placed 
across the top of the basin, the whole being covered with a bell jar. 
After several days the glass is examined and usually the less stable 
glasses show a duU, dimmed surface as compared with the more stable 
pnes. Another test proposed by Tscheuchner is to take several 


samples of glass, pack them in the same crucible with pulverized 
ferrous sulphate and heat for a time to dark red heat. The ferrous 
sulphate liberates vapors of SO3 which attack the glass. A com- 
parison may be made by washing, drying, and weighing the different 
samples. A somewhat more satisfactory test than either of the above 
depends upon the fact that aqueous ether solutions react readily with 
the less stable kinds of glass, and if a suitable dye, such as iod-eosin, 
is dissolved in the water-ether solution when one of the less stable 
glasses is immersed in the solution, a strongly adherent pink film 
will form on it. The density and depth of color of this film will be a 
measure of the stability of the glass. The best grades of glass will 
remain free from any colored film even on prolonged exposure. Dr. 
Zschimmer has devised a test somewhat different from the above. 
This depends on the fact that the disintegrating action of moist air 
can be very much accelerated if both the moisture and the tempera- 
ture of the air surrounding the glass be considerably increased. The 
samples of glass are, therefore, exposed to a current of air saturated 
with moisture at a temperature of about 80 degrees C or 176 de- 
grees F. in a specially arranged incubator, usually for several days. 
Different glasses will show different appearances after being sub- 
jected to this treatment. The most stable glasses will remain en- 
tirely unaffected, less stable ones will show small specks where they 
were attacked, while the least stable ones will show a dulled surface. 

All thes^ tests give one only a relative idea in regard to the stability 
of different glasses and it is somewhat of a question whether they will 
always fall into the same relative order under the influence of ordi- 
nary atmospheric action that they do under the influence of the 
agents used and under the conditions imposed upon them in the 

Almost all glasses undergo changes when exposed for a long time 
to the action of strong light, especially sunlight, or ultra-violet light. 
These changes are usually made manifest by a change in color. For 
example, many glasses containing manganese although at first they 
may be practically colorless, after prolonged exposure to the light 
will assume a purple or violet tinge. This may often be seen in the 
case of the glass globes surrounding arc lights or street lamps. 

The chemical behavior of different glasses at high temperatures, 
while they are still in the molten condition, is of great importance 
to the manufacturer. Some glasses will attack the clay vessels in 
which they are contained muclv more readily than others. 




The two most valuable physical properties of ordinary glass are 
transparency and rigidity at ordinary temperatures, passing to 
plasticity at high temperatures. These in addition to hardness and 
resistance to chemical change make glass such a useful substance. As 
in the case of the chemical properties of glass, the physical properties 
also vary with the chemical composition, so that glasses of different 
compositions may show widely different physical properties. 

The density of glass varies with the molecular weight of its con- 
stituents. Thorpe gives it from 2.25 in the case of the lightest borate 
glasses to 6.33 in the case of the heaviest lead and barium glasses, 
the average for lime-alkali glass being 2.5 and for lead flint 3.00. 
Trautwine gives the specific gravity of common window glass as 2.52 
and according to Kent the specific gravities of the ordinary lime- 
soda glasses of commerce vary from 2.5 to 2.75, and of lead flint 
from 2.88 to 3.14. 

Attention has already been called to the fact that transparency is 
one of the important physical properties of most glasses. Colorless 
glass transmits practically the whole of the visual spectrum in equal 
amounts, but the whole of the light falling on it does not pass through. 
A certain portion is reflected at the surface of entry, another at the 
surface of exit, while a still further portion is absorbed during its 
passage through the glass. In the case of the purest colorless 
glasses the portion absorbed is very small and practically 
uniform for rays of different wave lengths, as far as the 
visual spectrum is concerned, but it is never entirely so. Even 
these glasses will, therefore, show a slight color, usually a blue or 
green tint, if considerable thicknesses are examined. The best plate 
glass shows a slight greenish-blue tint, which is quite marked when 
the glass is viewed edgewise. Window glass, as a rule, has a decid- 
edly deeper Color. 

The optical properties of glass are very sensitive to variation in 
chemical composition and the methods of treatment employed in 
their manufacture. One of the most essential properties of optical 
glass is homogeneity, that is the glass must have the same density 
throughout. This is a rather difficult thing to attain in glass and 
ordinary glass never possesses it, so that when a thick piece of such 
glass is examined the threads or layers of different densities can be 
recognized in the form of minute internal irr^ularities in the glass. 
These defects are known as striae or veins and they must be avoided 
in glass which is to be used for the better kinds of optical work. 
Special means*are used to accomplish this. 



Transparency and color are also of prime importance. A good 
optical glass should absorb as little light and be as nearly colorless 
as possible. This can only be accomplished by using very pure raw 
materials in the manufacture and clay pots which will not react with 
the glass in such a way as to introduce undesirable impurities. 

The fundamental optical constant of each variety of optical glass 
is known as its index of refraction. Its value is obtained by divid- 
ing the sine of the angle of incidence by the sine of the angle of 
refraction. This ratio really represents the ratio of the velocity with 
which the light waves are propogated through the glass to the velocity 
with which they travel through the air. This ratio varies with the 
chemical composition of the glass and its physical condition, and 
also has a different value for light waves of different lengths. It 
varies directly with the specific gravity of the glass, a high specific 
gravity being accompanied by a high index of refraction while a low 
specific gravity gives a low index of refraction. The indices of re- 
fraction of different glasses used for optical purposes range from 
about 1.49 to 1.71. 

Attention has already been called to the fact that light waves of 
different lengths will be refracted differently in passing through 
glass. This property of glass is known as dispersion. It is of ex- 
treme importance in optical work. 

The lustre of glass depends largely upon its index of refraction and 
upon its ability to resist the action of atmospheric agents, for if the 
surface of the glass is attacked it will become dim and dull. The 
glasses with high indices of refraction have a more brilliant lustre 
than those with low ones. 

Hardness is a property which is of some importance in many of 
the applications of glass. By hardness we mean the ability of the 
glass to resist abrasion. This property varies with the chemical com- 
position and also with the rate at which the glass is cooled. As a 
general rule it may be said that glasses rich in silica and lime are 
hard, while those rich in alkilies, lead, or barium, are soft. Rapid 
cooling will produce a great increase in hardness even in compara- 
tively soft glasses. No satisfactoi*y method for measuring hardness 
has yet been devised. 

The mechanical properties of glass are often of considerable im- 
portance, as in the case of handling large sheets of plate glass or 
sheet glass, also in the case of guage tubes for high pressure boilers 
and other instances where glass is called upon to withstand consider- 
able pressure. These properties vary considerably with the com- 
position and also with the manipulation during manufacture, more 
particularly the rate and condition of cooling. Kent quotes the 
following figures from Fairburn for the mean tensile and crushing 
strengths of ordinary glasses: 


Tensile and Crushing 

Strengths of Glasses. 
























Mean Bpeclflc gravity, 

Mean teniile tsrength. pounds psr sq. In. in bars, ^ 

In thin plates, 

Mean crunblng strength, pounds per sq. in. in cylinders, 
In cubes. _. .- 






The bars In the tensile strength tests were about | inch In diameter. The crushing tests were 
made on cylinders about 3 inch in diameter and from 1 to 2 inches high and on cubes approxi- 
mately one Inch on aside. 

Trautwine gives the ultimate tensile strength of glass as 2,500 to 
0,000 pounds per square inch and the crushing strength as 6,000 to 
10,000 pounds per square inch. In a series of special glasses in- 
vestigated by Winkelmann and Schott at Jena the modulus of 
elasticity (Youngs modulus) varied from 3,500 to 5,100 tons per 
square inch, the value being largely dependent* upon the chemical 

Olass is an exceedingly brittle substance at ordinary temperatures. 
Its brittleness increases with the rapidity at which it is cooled. 
Measureable ductility has not been observed in glass under ordi- 
nary conditions. 

The electrical properties of glass are of Considerable importance, 
as glass is frequently used in electrical appliances ds an insulating 
medium. Its insulating properties vary greatly with the chemical 
composition. As the rule the harder glasses, that is those high in 
silica and lime, are the best insulaters, while soft glasses, such as 
those high in alkali and lead, are much poorer in this respect. As 
has already been stated glass tends to condense a thin film of mois- 
ture from the atmosphere upon its surface which attacks the glass 
to a certain extent, different glasses varying considerably in the de- 
gree to which they display this hygroscopic tendency. As a rule the 
softer glasses are much more hygroscopic than the hard ones, and in 
some cases the resulting film of surface moisture serves to lessen or 
even break down the insulating power of the glass by allowing the 
electricity to leak away along the film of moisture. In the case of 
appliances for static electricity, where very high voltages are diealt 
with, an attempt is sometimes made to avoid this leakage by varnish- 
ing the surface of the glass with shellac or some similar substance. 

The thermal properties of glass although not of such general 
importance as the mechanical properties nevertheless have to be 


taken into consideration in the case of a large number of uses to 
which glass is put. One of these properties is that known as thermal 
endurance, which measures the amount of sudden heating or cooling 
to which glass may be exposed without fracturing. This depends 
upon a number of factors, the chief of which are tensile strength 
iind elasticity, and the relation between thermal conductiveity and 
expansion. An illustration will show how these operate in determin- 
ing the thermal endurance. If a hot liquid is poured into a glass ves- 
sel, the material of the inner layer of ^ass expands or endeavors to 
do so, being restrained by the resistance of the central and outer 
layers of material which are still coM. The inner layer is, therefore, 
in a state of compression while the middle and outer layers are 
under tension. If this tension is sufficiently great the outer layers 
will fracture and the vessel will be shattered. A high coefScient of 
expansion and a low modulus of elasticity will b6th favor fracture, 
while a high tensile strength will tend to prevent it. The thermal 
conductivity of the glass will also affect the result, because the in- 
tensity of the tensile stress set up in the colder layer will depend 
upon the difference in temperature. The heat capacity, or specific 
heat of the glass, also has an influence on the thermal endurance, as 
heat will penetrate more slowly through a glass whose own rise 
in temperature absorbs a greater quantity of heat. The endurance 
ife higher in glass rich in silica and low in lime and alumina, and 
is greatest in pure quartz glass, which is able to withstand extensive 
variations of temperature without fracture. 

Glass is always a comparatively poor conductor of heat. The coeffi- 
cient of thermal expansion varies considerably in different glasses. 
Trautwine gives the following linear expansion for glass for 1 degree 
F. rise in temperature. 

Glass rod 1 foot in 221,400 feet 
Glass tube 1 foot in 214,200 feet 
Glass crown 1 foot in 211,500 feet 
Glass plate 1 foot in 209,700 feet. 

Rosenhain gives the limiting values for the cubical expansion per 
('egree Centigrade as 37x10-^ for the lower and 122x10-^ as the upper 
limit. Thorpe gives the mean cubical expansion of soda-lime glass 
as lying between 0.000023 and 0.000027. The relative expansion 
becomes of great importance when two different glasses have to be 
fused together, as in the case of flashed glass and the decoration of 
glass by enamels. In most cases the expansion is not uniform and 
for the construction of instruments like thermometers, where such 
a defect introduces serious error, special glasses have to be made. 

The fusibility of glass depends upon its chemical composition. 
This restricts the range of possible compositions of glasses which 


can be manufactured on a commercial basis to those which can be 
obtained under the temperature of 1,600 degrees C, or 2,900 degrees 
F., as temperatures exceeding this cannot be produced in the ordin- 
ary type of furnace. 

In working glass it cools so rapidly that a tension is developed 
between the outer and inner layers. The outside layer cools and 
hardens first, while the inside layers are still soft. When the inside 
layers cool and harden they tend to contract and draw away from 
the outer ones, but as the latter are already harti and rigid the 
result is not a contraction of the whole mass but the development of 
a tension between the layers, the amount depending upon the rapid- 
ity of the cooling. This tension makes the glass tough, bard and 
strong and gives it great thermal endurance as long as the surface is 
left unbroken. As soon, however, as the surface becomes scratched 
or broken, thus relieving the tension, the glass files into fragments. 
For this reason glass intended for ordinary use must be cooled 
Rlowly so that the outside and the inside layers will cool nearly simul- 
taneously and all tension between them avoided. This is known 
as annealing the glass and will be idiscussed in more detail in a later 




The raw materials employed in the manufacture of glass may 
he divided into two groups: — those which on being melted together 
make up the glass substance itself and those which are used to bring 
about a change in the raw substances or the glass in any direction, 
but are not necessary for the formation of .the glass substance itself. 

The first group may again be divSded into two classes of sub- 
stances: — those which furnish the acidic ingredients of the glass and 
those which furnish the basic ones. There are a number of raw 
materials, however, which furnish both types. These will be taken 
np under the basic oxide yielding class. In the second group are 
included all materials for clarifying, decolorizing, and coloring glass. 

Silica. SIO,. 

Silica is the most important constituent entering into the com- 
position of glass. There is no glass in the technical sense which 
does not have silica as an important constituent. It can only be 
replaced to a small extent by other acidic oxides, which is done in the 
case of some of the glasses used for optical and other special pur- 

Silica, next to oxygen, is the most abundant element found in 
nature. It occurs in combination with oxygen as the oxMe, SiOj, in 
the form of such minerals as quartz, tridymite, chert, flint, chal- 
cedony, and opal, and in combination with many of the basic oxides 
it enters into the composition of a large group of minerals known 
as the silicates. According to F. W. Clarke 59.85% of the earth's 
lithosphere consists of SiOg. 

For purposes of description the many forms of quartz may be 
divided into three groups, namely: vitreous, chalcedonic, and jaspery 
cryptocrystalline varieties. Besides quartz, silica also occurs in na- 
ture as the mineral tridymite, and combined with varying amounts 
of water as opal. The following list is that given in Dana's Manual 
of Mineralogy and Petrography. A few of the less common forms 
have been omitted by the writer. 

Vitreous Varieties of Quartz. SiOi. 

Rock Crystal, Pure pellucid quartz. Specific gravity 2.65. 

Amethyst. Purple or bluish violet, and often of great beauty. 
Color disappears on heating and is probably due to a little manganese. 
Specific gravity 2.G5 to 2.66. 



Rose Quartz. Pink or rose colored. Seldom -occurs in crystals; 
generally in masses much fractured, and imperfectly transparent. 
The color fades on exposure to light. Probably colored by titanium 
or manganese. Specific gravity 2.65. 

Yellow Quartz, or False Topaz. Light yellow pellucid crystal*. 

i^moky quartz. Crystals of a smoky tint ; the color is sometimes so 
ilark as to be nearly black and opaque except in splinters. The 
smoky color is due to some carbon compound. Specific gravity 2.G5 
lo 2.66. 

Milky Quartz, Milk white, translucent to nearly opaque, massive, 
and of common occurance. It is a constituent of many rocks. 
Often has a greasy lustre, and is then called greasy quartz. Specific 
gravity 2.64 to 2.66. 

Aventurinc Qnnrtz, Common quartz spangled throughout with 
scales of golden yellow mica hematite, or goethite. Usually translu- 
cent, and gray, brown or reddish brown in color. 

Ferruginous Quartz. Opaque, anid either of yellow, brownish-yel- 
low, or red color from the presence of iron oxide. 

Ohalcedonic Varieties. 

Chalcedony. Translucent, massive, with a glistening and some- 
what waxy lustre, usually of a pale grayish, bluish, whitish, or light 
brownish shade. Not found in crystals. Frequently nodular, mam- 
millary, or stalactitic. Often occurs lining or filling cavities in 
amygdaloidal and other rocks. The cavities are little caverns into 
which siliceous waters have, at some period, filtered and deposited 
their silicaw 

Chrysoprase. Apple green chalcedony, colored by nickel. 

Canwlian. Bright red chalcedony, of a clear, rich tint. 

Sard. A deep brownish-refl chalcedony, of a blood-red color by 
transmitted light. 

Agate. A variegated chalcedony. The colors are distributed in 
clouds, spots, or concentric bands. These bands take straight, cir- 
cular, or zigzag form. 

Onyx. A kind of agate having the colors arranged in flat hori- 
zontal layers. The colors are usually light clear brown and an opaque 
white. When the stone consists of sand and white chalcedony in 
alternate layers it is called sand onyx. 

FUnt, Homstone, Chert. Massive compact silica, of dark shades 
of smoky gray, brown or even black, feebly translucent, breaking with 
sharp cutting edges and a conchoidal surface. Flint occurs in no- 
dules in chalk, not infrequently the nodules are chalcedonic. Hom- 
stone differs from flint in being more brittle, impure homstone. 
Limestones containing hornstone or chert are often called cherty 



Silicified Wood. Petrified wood often consists of quarts, quartz 
having taken the place of the original wood. In some specimens 
the wood is converted into chalcedony and agate of various colors, 
having great beauty when polished. 

Jaspery Varieties. 

Jasper. A dull opaque red, yellow, or brownish siliceous rock. It 
olso occurs of green and other shades. 

. Bloodstone or Heliotrope. Deep green, slightly translucent, con- 
taining spots of reld, which have some resemblance to drops of blood. 
Contains a fevi, per cent of clay and iron oxide mechanically combined 
with the silica. The red spots are colored by iron. 

Lydian stone, TouchstonSy Bassanite. Velvet black and opaque 
and used on account of its hardness and black color for trying the 
purity of precious metals ; this is done by comparing the color of the 
mark left on it with that of an alloy of known character. 

Opal. SiO.H-nH.O (1% to 20% H,0). 

Compact and amorphous, texture colloid; also in reniform and 
stalactite shapes; also earthy. Color white, yeUow, red, brown, 
green, blue, and gray. The finest varieties exhibit from within, when 
turned in the hand, a rich play of colors of 'delicate shades. Lustre 
waxy to subvitreous. Hardness 5.5 to G.5. Specific gravity 1.9 
to 2.3. - 

Precious opal. External color usually milky, but having a rich 
play of delicate tints ; a gem of rare beauty. 

Fire opal. An opal with lellow and bright hyacinth -or fire-red 

Common opal, Semi opal. Has the hardness of opal and its waxy 
or resinous luster, but no colored reflections from within, though 
sometimes a milky opalescence. The colors are white, gray, red, 
yellow, bluish, greenish, to dark grayish green. Translucent to 
nearly opa'que. 

Hyalite. Glassy, transparent; occurs in small concretions, occa- 
sionally stalactitic. Resembles somewhat transparent gum-arabic. 

Wood opal. Gray brown, or black, having the structure of wood, 
being wood petrified by hydrated silica (or opal) instead of quartz. 

Siliceous Sinter, Oeyserite. A loose, porous, siliceous rock, grayish 
to white in color, deposited around geysers, as those of Icelantd and 
Yellowstone Park, in cellular or compact masses, sometimes in sta- 
lactitic or cauliflower like shapes. 

Tripolite. Diatomaceous or Infusorial Earth. A white or grayish- 
white earth, massive, laminated or slaty, made mainly of siliceous 
secretions of microscopic plants, called diatoms. Forms beds of con- 
siderable extent and often occurs beneath peat (because diatoms 

. Wniriiii N.i. 

Fig. 2. Sand groini of same sise, Wedron No. 1 sand. 

lived in the waters of the shallow pond before it became a dying 

Quartz crystallizes in the rhombohedral division of the hexagonal 
system. When the crystal form develops it often consists of an 
hexagonal prism terminated by two rhombohedrons or sometimes only 
of double six siided pyramids made up of two rhombohedrons. Us- 
ually it occurs in the massive form with no crystal faces developed. 
These occurrences vary in their texture from coarse to fine grained 
or even to crypto crystalline, as in the case of the chalcedonic and 
jaspery varieties. Quartz does not tend to break along any well 
defined planes, in other words it has no cleavage, but breaks with 
equal readiness in any direction. It usually breaks with a more or 
less rounded or curved surface, and is therefore said to have con- 
choidal fracture. Its hardness accoitiing to Moh's scale is 7, which 
makes it a comparatively hard mineral. In specific gravity it varies 
from 2.653 to 2.654. In thin sections quartz is colorless, but often 
shows inclusions of various kinds which serve as pigments and give 
a color to thick slabs and masses of the mineral. At times, therefore, 
it may be yellow, red, brown, green, blue, or even black in color. It 
has a glassy or vitreous lustre. 

According to Day and Shepherd quartz fuses at a temperature of 
about 1,600° C, or 2,91^° F. When finely ground quartz is heated 
with tungstate of soda it remains unchanged until a temperature of 
about 870° C is reached. At temperatures above this it is gradually 
converted into tridymite. Tridymite occurs in nature as a mineral in 
certain volcanic lavas, especially the more siliceous and feldspathic 
kinids, as small aggregations in the massive rock, or also frequently 
in cavities associated with quartz or opal massive rock, or also fre- 
quently in cavities associated with quartz or opal and feldspar. 
It has also been found in meteorites. Tridymite is stable at all 
temperatures from 870°dbl0C up to 1,470°±10C, where the inversion 
to a third form known as Cristobalite takes place. From 1,470°C on, 
no further change occurs up to the melting point.^^ 

Quartz is unattacked by acids other than hydrofluoric, and is 
only slightly attacked by solutions of the fixed caustic alkalies. This 
resistance to the attack of the ordinary acids explains the general 
absence of alternations in the quartz crystals of rocks, except where 
they have been subjected to profound alteration or metamorphism. 
Ordinary processes of alteration antt decomposition do not affect 
quartz. It appears fresh and unaltered when other minerals have 
been decomposed. 

Attention has already been called to the fact that quartz isn)ften 
colored by the presence of inclusions. These may be divided into 

11. The TtrioQs forms of tiUcm and their mntnal relttlonn. Clarence N. Fenner. Jomva] of **** 
Washington Academy of Sciences. December 4, 1012. (Vol. 2.) 


^'aseous, liquid, and solid substances, the latter usually consisting 
of minerals of various kinds. The gas and liquid inclusions usually 
occupy irregular shaped cavities in the quartz, although sometimes 
they have the form of the enclosing mineral. The liquid in most 
cases is water, but liquid carbon dioxiJde may also be present. Gas- 
eous babbles, sometimes movable, often accompany the liquid. Cubes 
of some colorless mineral, possibly sodium chloride, are also found 
at times in these cavities. At other times a carbide is present in 
the liquid. This causes the fetid Oder of certain samples of quartz 
when struck a sharp blow. The milky white color developed in 
certain quartzes is generally due to the reflection of light from these 
inclusions of gas and liquid. 

Among the solid inclusions found in quartz are a considerable 
number of minerals. One of the most common of these is nitile, a 
titanium oxide, which often occurs in quartz as extremely thin 
microscopic needles. Minute crystals of apatite arid plates of ilmenite 
abound in blue quartzes found in certain granites and porphyries. 
Other minerals occasionally found in quartz as inclusions are needles 
of tourmaline, epidote, actinolitc, tromolite, and chlorite. These are 
the most common mineral inclusions, but others have also been found 
in certain quartzes. They are often arranged along linos, curved sur- 
faces, or sometimes parallel to the cr^-stal faces of the quartz. 

Quartz is one of the most abundant minerals found in nature. 
It is an essential constituent of many igneous rocks, among the more 
important of which may be enumerated rhyolitc, granite, dacite, 
quartz dioritc, and granite pegmatite. In such sedimentary rocks 
as sandstone and conglomerate and the corresponding loose mate- 
rials, sand and gravel, from which these are derived, it is usually 
the chief, and often nearly the only constituent present. In many of 
the metamorphic rocks such as the quartzites, gneisses and mica 
schists it is also important constituent. In addition to the above 
occurrences it is a very important vein forming mineral, frequently 
filling fissures and other cavities and crevices in the rocks. Consider- 
able quantities are also deposited at times by hot springs and geysers. 
F. W. Clarke estimates that quartz fonns about 12% of the entire 

From its widespread distribution in nature it will be readily recog- 
nized that the mineral quartz must form under a great many different 
conditions. Where it occurs as an important constituent of certain 
types of igneous rocks it has cr\\stallized directly from the molten 
contdition. It is usually one of the last minerals to separate out 
when crystallization takes place in a cooling Liva or niacfnia. Quartz 
cccuring as a vein filling in fissures and otiier crevices in the earth's 
crust has crystallized out from water solutions. These solutions 
ay have been at high temperatures at the time the crystallization 


took place or they may have been at ordinary temperatures, the 
mineral being found in both types of veins. Quartz therefore forms 
in nature either as a direct crystallization product from molten 
magmas or by precipitation from water solutions. 

From the standpoint of the glass manufacturer only a few of the 
many occurrences of quartz are of interest as a possible source of 
silica for his use. At the present time pure quartz sands made 
up entirely of little quartz grains varying in size from 0.1 to 0.4 
millimeters in diameter furnish practically the only source of silica 
for the glass industry. 

As has been stated before, quartz is an important constituent 
of many of the rocks which make up the lithosphere or solid portion 
of the earth. Rocks are simply aggregates of one or more minerals. 
They can be divided into three large groups, namely: — igneous, 
•sedimentary and metamorphic. Igneous rocks are those which have 
lieen formed by consolidation direct from the molten state, sedi- 
mentary are those which have been formed by the accumulation 
and consolidation of materials derived from the mechanical disin- 
tegration and chemical decomposition of previously existing rocks 
of any one of the above types, by the various agents of weathering, 
and metamorphic rocks are those which, originally igneous or sedi- 
mentary, have been altered in texture, structure or composition 
through any one or more of the various geologic agencies. Rocks 
are found in all three of these groups which have quartz as an 
essential constituent. Among igneous rocks such types as rhyolite, 
granite, dacite, and quartz diorite may be mentioned, in the case of 
sedimentary rocks, sandstones and conglomerates, and among meta- 
morphic rocks, quartzites, mica schists and gneisses.^ 

For the purpose of glass manufacture, however, it is necessary, 
that quartz be not only an essential constituent of the rock but it 
must be practically the only constituent present. This type of rock 
is found only in the case of certain sandstones among the sedimentary 
rocks. Sand deposits and sandstones are found in nature that anal- 
ize over 99% SiOg. It is therefore in the occurance and origin of 
this type of sedimentary rock that the glass manufacturer is par- 
ticularly intersted. 

As has already been stated, sedimentary rocks are derived from 
materials produced from the mechanical disintegration and chemical 
decomposition of previously existing rocks on the earth's surface 
which have been exposed to the action of the various atmospheric 
agents, such as the gases present in the air and rain, frost, and 
changes of temperature. The alteration which takes place when 
rocks are thus exposed is known as weathering. Under ordinary 
conditions it involves both mechanical and chemical changes in tb** 
locks exposed at the earth's surface. 


Temperature changes and frost are the most active in producing 
mechanical disintegration of the rocks which crop out at the earth's 
surface. Where naked rocks are exposed to the direct rays of the 
bun during the day the outer layers become heated and expand. 
As rocks are poor conductors of heat only a comparatively thin 
shell is affected. At night these same rocks are cooled from the 
surface inward and contract, the outermost portion cooling off first, 
while a little further down the rock is still heated. This causes 
stresses to be set up in the rock, which after a time are sufficient to 
cause it to exfoliate or split off from the surface. Crevices and 
lissures in the rocks are also gradually widened by these stresses. 

Most rocks are made up of aggregates of more than one mineral. 
Each of these minerals will have a different coefficient of expansion. 
When, therefore, the temperature rises the minerals expand and 
crowki against each other, and when the temi)erature drops they 
contract and draw further apart. The stresses thus produced by 
the unequal expansion and contraction of the minerals making up 
ii rock will cause the formation of small cracks, by which water will 
get access to the rock and set up chemical action, or in which the 
roots of plants will get a hold and further disintegrate it. 

Most rocks are traversed by fractures, cracks and joints of various 
kinds, running in different directions. They are also more or less 
porous. Water gets into these openings and, if the temperature 
drops sufficiently, it freezes. In doing so it expands about 1-10 of its 
original volume and exerts a pressure of about 150 tons to the 
square foot. When the entire opening is full of water at the time 
the freezing occurs a tremendous force will thus be exerted on the 
rock, which terids to disrupt it. In this manner rocks are broken 
• down into smaller and smaller fragments at the earth's surface. 
The above examples illustrate some of the more important ways 
in which rocks are mechanically disintegrated. These do not involve 
changes in the chemical composition of the rock. 

Moisture, especially when it condenses in the form of rain, is the 
most active agent of the atmosphere in producing chemical decomposi- 
tion. A part of the rain which falls on the earth's surface evaporates 
again and passes into the atmosphere, a part runs off the surface 
and finds its way into streams and rivers, while a third portion 
soaks into the ground. It is this portion which is the active agent 
in producing chemical decomposition of the mineral constituents 
which make up the rocks. 

Rain water always contains in solution varying amounts of the 
gases present in the atmosphere, among which oxygen and carbon 
dioxide are the most active chemically. As has already been stated 
]>ractically all rock masses are traversoW by fractures and cracks of 
varying size and the rocks themselves are more or less porous. 
The water which soaks into the ground traverses these crevices in 


its downward course and thus comes in contact with the minerals 
of the rock, which it attacks. 

The most important chemical reactions which result are hydra- 
tion, oxidation, carbonation, and solution. Hydration consists, in 
the absorption of water which rei^ults in the production of hydrous 
minerals. Oxidation consists in the conversion of compounds of 
a lower state of oxidation to ones of a higher state. Carbonation 
consists in the union of carbon dioxide with bases to form car- 
bonates. Carbon dioxide replaces silica in silicates. Many of the 
compounds formed by the above reactions are more or less soluble in 
water and are, therefore, dissolved by the ground water as it perco- 
lates through the rocks and are carried away in solution. 

As a result of these processes of weathering, involving mechanical 
disintegration and chemical decomposition of the rocks exposed at 
the earth's surface, a loose mantle of material accumulates when- 
ever the various agents of transportation, such as wind and water, 
are not sufficiently active to remove it as fast as it forms. Soil 
is the name which is commonly given to this mantle. It consists 
largely of unaltered, or only partially altered, fragments of the 
original rock, in addition to the various secondary minerals (derived 
from the alteration of the original minerals which made up the 
rock from which it is derived. Certain of the rock minerals are 
attacked readily and, therefore, disappear in the soil, being repre- 
sented only by alteration products derived from them. The mineral 
orthoclase, which is one of the important minerals in certain igneous 
rocks, may be taken as an example to show how the agents of the 
atmosphere will attack and decompose a mineral. The reaction 
is as follows: 

2KAlSi308+ 2H20+CO,=H,Al2Si20,+48i02-f K2CO3 
Orthoclase+water-[-carbon=kaolin +silica+potassium 

dioxide carbonate 

In the above case the kaolin will remain behind in the soil as a 
fe^oft clayey mass. The silica when first liberated is a little more 
soluble, and may be carried away in part in solution, to be precipi- 
rated again at lower levels in the form of quartz. The potassium 
carbonate is readily soluable in water and goes into solution. Most 
of the other rock making minerals are attacked in a similar man- 
ner, some more and some less readily than orthoclase, the resulting 
I roducts forming a soft, loose, clayey mass. The mineral quartz, on 
the other hand is very resistant and remains practically unaltered 
by the above agents of weathering. It is therefore left behind in its 
original condition in the residual mantle formed after the process 
of weathering has gone to completion. 

The little grains of quartz of the original rock will, therefore, bf 
distributed through the soft, loose clayey material derived froi 


the alteration of the other important rock making minerals. In 
order to get a quartz sand it is now necessary for one or more of 
the various agents of transportation present in nature to remove 
this weathered material from its original position and separate the 
quartz from the clayey material or soil in which it is imbedded. 

Running water is one of the most important transporting agenta 
found in nature. A part of the rain which falls on the earth runs 
over the surface, carrying portions of the soil with it. This runs 
off, collects to form streams, whicli unite to make rivers. Weathered 
material is thus washed into the streams and is carried along by 
them, either in mechanical suspension or rolled along the bottom. 
The amount of material transported depends upon the velocity and 
volume of the stream. Whenever the velocity is checked, deposition 
occurs. The coarser materTal is deposited first, likewise the heavier. 
A separation according to size and specific gravity therefore results, 
anld thus streams act as sorting as well as transporting agents. 

The coarsest material, known as gravel, consists largely of more 
or less rounded fragments of unaltered, or partially altered, rock 
which have been washed into the streams. The next material in size, 
ir. called sand. This is made up of grains which approximate in size 
those of the minerals which made up the original rock. Therefore 
sand carried by streams consists largely of quartz grains, for, as 
has been pointed out, the other rock making minerals tend for the 
most part to be decomposed by the process of weathering into soft, 
readily pulverized, secondary minerals, which give rise to the fine 
ilt and mud carried by the streams. The relative percentage of 
quartz present Idepends largely on the degree of completion which 
the process of weathering has attained 'before the material was 
washed into the streams. Quartz is also harder than the other 
common rock forming minerals and does not suffer so much from 
wear, due to attrition of colliding grains during transportation as 
do the other minerals, unaltered fragments of which may be present 
in the sand, these latter being gradually worn to a fine silt. The 
finest material, the silt and mud, carried by streams in mechanical 
suspension consists largely of secondary minerals, such as kaolinite, 
and other hydrated silicates of aluminum, limonite. etc. This is the 
last material to settle out when the velocity of the stream is checked. 

Streams deposit the material which they carry mechanically at 
various places along their courses and at their mouths, where they 
enter bodies of standing water. Deposition occurs wherever there 
is*a decrease in velocity. When streams flow from mountainous 
regions onto plains, large deposits, in the shape of alluvial fans and 
cones, are often built up on the plain at the base of the mountains. 
A number of these fans may coalesce to form a large alluvial plain. 
As a rule sorting is very imperfect in these deposits and sand of 

Fis. 1. Saail liunca along dry channel of Rio Puorco, south of Adamana, AriEODO. 

h '* 




, Rio I'lirn'o vail.T, Aiiiilnana. Ari: 


sufficient purity for glass making is rarely found in them. At times, 
however, especially if the stream is deriving its material from an 
already fairly pure quartz sandstone formed during some previous 
geologic period, fairly pure quartz sands may accumulate under ' 
those conditions. The Pottsville sandstone of western Pennsylvania, 
formed during the early part of the Pennsylvania period, represents 
such a deposit. 

Streams also deposit considerable amounts of material at various 
places along their courses, especially the lower portions, so that 
sand deposits are often found along the flood plains of rivers. At 
times these ideposits are of sufficient purity to be used in the manu- 
facture of glass. Such deposits were formerly worked along the 
Monongahela river in the vicinity of Belle Vernon, Pa. 

Finally, all material still carried mechanically by the stream when 
it enters a body of standing water is deposited at or near the 
mouth of the stream. Here sorting is usually more perfect. • The 
coarse material, or gravel, come to rest first, then the sand, and 
finally the mud and silt. Where the stream enters a large lake or 
the ocean wave action further assists in the sorting, by washing 
out the finer material from the sand. In the case of the ocean the 
waves, undertow, rising and falling tides, and shore currents due to 
v/aves striking the shore at oblique angles, all assist in this soiling, 
so that at times deposits of nearly pure quartz sand result. The 
attrition of the colliding grains also gradually wears the softer ones 
down to a fine powder which is washed away, until eventually only 
the harder ones like quartz remain behind. If the coast is a grad- 
ually subsiding one such deposits may reach a thickness of several 
hundred feet. The Oriskany sandstone of central Pennsylvania rep- 
lesents a deposit of this character formed during the early part of 
the Devonian period. Sands running over 99% SiOj are reported as 
accumulating at the present time along the gulf coast of Florida 
in the vicinity of Pensacola and Tarpon Springs.^^ 

Wind is another transporting and sorting agency which at times 

in conjunction with running water, or at times alone, is instrumental 

in the accumulation of extremely pure quartz sands. The ultimate 

source of the material transported by the winds is also derived largely 

from the products of atmospheric decay, which may or may not have 

been transported by water previous to the time it was taken up 
by the wind. Dry sand is readily blown about by the wind. Where 
the wind is in some prevailing direction it carries the sand along 

with it, heaping it up in the form of dunes, which are hills of sand 
similar to the drifts formed in the case of snow which is being borne 
along by the wind. Plate II shows the appearance of such dunes 
occuring along the valley of the Rio Puerco at Adamana, Arizona. 

12. United States Oeologlctl Sonrey. Mineral Resoureet of the United States, 1011, Part 2, pi» 


The large grains of sand are carried along close to the surface, 
while the finer particles are carried to considerable heights by the 
wind. In this way the fine material is separated from the coarse. 

The unequal hardness of different minerals plays a much more 
important part in the separation which occurs in wind blown sands 
than it does in river sands. The grains do not have a cushion of 
water to protect them from abrasion by one another as they are 
llown along by the winds. As a result the softer ones gradually 
l>ecome reduced to dust, which is blown away by the wind, while the 
harder ones remain behind. Quartz is among the hardest of the 
common minerals present in sand so that the more handling the 
sand receives by the wind the greater becomes the percentage of 
quartz present. Until finally a practically pure quartz sand, made 
up of well rounded grains results. The rounding of the grains 
may often be used as a criterion to distinguish wind blown sands 
from 'water laid sands, as the latter are usually more or less angular, 
because grains the size of ordinary sand are protected from abra- 
sion by the cushion of water around them. Victor Ziegler carried on 
some experiments which letd him to the conclusion that quartz grains 
less than 0.75 milimeters in diameter could not be rounded under 
water, but if rounded they were wind worn.** Wind worn grains 
also loose their glassy character and become dimmed by attrition, 
so that the surface of the grains assume the appearance of ground 

Wind blown sands frequently occur along low lying sea-coasts, 
fllong river flood plains in arid and semi-arid regions, and in desert 
legions. The St. Peter sandstone, which is quarried so extensively 
for glass sand around St. Louis, Missouri and at Ottawa, Illinois, 
is an example of a wind blown sand, deposited on a low-lying plain, 
• occupying the upper Mississippi valley region during the early part 
of the Ordovician period. 

Sands which are deposited over a gradually subsiding area may 
become burieil to very considerable depths by later sediments laid 
down on top of them. If a little clayey material was deposited with 
the sand the pressure may be sufficient to consolidate the mass into a 
rock. At other times the sand is bound together by mineral matter 
deposited between the grains from water solutions percolating 
through the sand. The most common cementing agents are silica 
(SiOa), calcite (CaCOg), dolomite (CaCOg.MgCOg), and iron oxides, 
usually the hydrated ferric oxide, known as limonite, but at times 
also the simple ferric oxide, hematite. Where iron oxide forms the 
bond the sandstone is rendered unfit for glass making. 

Deposits of sand and resulting sandstones formed as outlined above 
may, during a later stage in the geologic history of a region, become 

'^. Journal of Geology. Volnmc XJX, pp. 646-664. 

I'LATt; 111. 


mii'msmiili o 

iiuiirt^iiti' frcim Tusi- 

JnokH Moimti 

a. Mmil.ton, Fn. Cn 


elevated vertically to varying heights above sea level. Erosion may 
remove the overlying sediments and expose the sandstone again 
at the surface. At times also in its geologic history a fegion which 
has undergone gradual subsidence over a considerable interval of 
time, with the deposition of a thick series of sedimentary rocks, 
may become subject to lateral compression produced by the gradual 
shrinkage of the earth. The horizontal layers of the rock are then 
thrown into a series of arches and troughs, called anticlines and 
synclines respectively, and the beds thus become tilted at various 
angles. The great pressure brought about by this lateral compres- 
sion, acting in conjunction with a somewhat higher temperature 
due to the burial of the rocks to a considerable depth beneath the 
earth's surface, often causes considerable recrystallization to occur 
in the rocks, so that a sandstone becomes converted into an ex- 
tremely hard and tough quartzite. Small amounts of water present 
between the grains of sand also assist in this recrystallization. 
During this process the original grains become entirely obliterated 
and a clear quartz mosaic results. Plate III is a photograph of a 
thin section of quartzite, used for silica brick, from Mapleton, Penn- 
sylvania, as it appears under a petrographic microscope with cross- 

When the sandstone is again elevated above sea level by move- 
ments underneath the earth's surface and exposed to weathering by 
the process of erosion, the tendency again is to convert it into loose 
sand. The rate at which the agents of weathering disintegrate it 
depends largely upon the bond. A sandstone with calcite as a bond, 
for example, disintegrates to a loos^sand much more readily than 
one with a silica, clay material, or iron oxide bond, because calcite 
is comparatively realdlly soluble in water containing carbon dioxide. 
At and near the surface, therefore, sandstone often become quite 
friable, due to weathering, and can be readily crushed to sand for 
glass making purposes, provided the stone is sufficiently free from 
deleterious constituents. 

An ideal sand or sandstone for glass making would consist entirely 
of quartz grains. In as much as absolutely pure quartz sands or 
sandstones are not found in nature, however, it becomes necessary 
to determine what impurities are permissable and to what amounts 
they may occur in a sand and still not render it unfit for the manu- 
facture of glass. This depends largely upon the kind of glass for 
which the sand is to be used. Optical and high grade lead flint 
glass require a much purer sand than ordinary or bottle glass. The 
size and shape of the sand grains are factors which must be con- 
sidered, but these are not nearly so important as the chemical 
composition of the sand. 


When a quantitative analysis is made of a glass sand there are 
I Kually found in addition to the silica small amounts of AljO,, Fe,Og, 
MgO, CaO, H2^> ^^^ TiOg, also occasionally a little NajO, B^jO, and 
organic matter. This is due to the fact that there are usually 
present, even in the purest sands, minute amounts of other minerals, 
such as mica, especially muscovite and sericite; feldspar, including 
orthoclase, microcline, and plagioclase; hornblende; titanite; mag- 
retite; ilmenite; sphene; rutile; zircon; apatite; kaolinite, or other 
hydrated aluminum silicates; limonite, hematite, calcite, dolomite, 
chlorite, etc. 

Alumina occurs in glass sands usually either in the form of feld- 
spar (either orthoclase (KAlSigOg), or plagioclase (mNaAlSijO,- 
+nCaAl2Sia08) ), muscovite (H2(K,Na)Al8( 8104)3), or kaolinite (H^- 
AlgSijOg). The latter is the most frequent occurrence. The small 
quantities of ciayey material associated with most sand deposits 
consist largely of this or «^ome very similar hydrated aluminum 
silicate. Kaolinite and muscovite may be removed, at least in large 
part, by washiLg the sand. Grains of unaltered feldspar, on the 
other hand, cannot be very well separated from quartz grains in 
this manner. 

There is still some difference of opinion among manufacturers 
as regaVds the effect on the glass of alumina in sand. Some regard it 
as a harmful constituent, while others do not. In fact there is con- 
siderable evidence to show that in the case of certain glasses it is 
even advantageous to have it present in small quantities. 

Dralle cites a number of examples and gives the results of experi- 
ments which indicate that alumina in high lime glasses tends to 
leduce their tendency to devitrify. Hovestadt also cites an example 
which occurred in actual practice. This was a thermometer glass 
made in the Thuringian Forest of Germany which would stand re- 
peated melting, blowing, and fusing without change, while ordinary 
glass, such as is used for windows, became rough and dull of sur- 
face even on short exposure to the flame. Upon inquiry it was 
found that the Thurningian glass owed its special qualities to a 
certain sand used in' its manufacture, which was only found" in the 
neighborhood of the village, of Martinsroda. Upon analysis it was 
found that this sand contained 3.66% alumina. Experiments with 
pure quartz sands to which this amount of alumina was added gave 
exactly the same results as the Martinsroda sand, showing that the 
special properties imparted to the Thuringian glass by the Martin- 
sroda sand were due to its alumina content. Schott suggests that 
the presence of the alumina hinders the volatilization of the alkalies 
at the surface of the glass, but it is also possible that the dulling 
of the glass is due to incipient crystallization or devitrification and 

that the alimina tends to prevent this. Frink^* has also observed 

, *^ 

14. TranBactloni American Certmlc Society, Vol. IT, 1909, pp. 99-103. 


that when alninina exists to the extent of 3 or 4 per cent in a finished 
glasH the glass is not nearly so susceptible to the carbonizing or 
reducing action of the fire, or to the formation of cords and strings, 
cr production of a laminated condition, whether soda or salt cake 
be used for supplying the soda content. Dralle also states and 
gives examples indicating that alumina has a very favorable in- 
fluence in the durability of glass by decreasing its solubility in water, 
^-^eak acids, etc. Frink^^ has found the same thing to hold true of a 
large number of bottle glasses of known composition. 

Alumina has also certain favorable influences on the physical prop- 
erties of glass. Frink*® states that from his observations he ia 
lead to conclude that alumina has the tendency to increase ihe 
surface tension when the surface is rapidly chilled. This is a valu- 
able property in the manufacture of glass in molds, for when a glass 
containing 3 to 5 per cent of alumina has been gathered or ladled 
from a mass of molten glass at a temperature of about 1150® C, its 
surface immediately becomes lower in temperature, dropping to about 
825*^ C, and the skin or overlying stratum will become very tenaceous. 
When a glass of this character is placed in the molds and is pressed 
or blown it has less tendency to take on the various small imper- 
fections in the mold, but at the same time it will 'be sufficiently 
plastic to be forced into any shape. Alumina is an especially val- 
uable ingredient in the manufacture of bottle glass because it re- 
duces the coefficient of expansion and increases the tenacity of the 
glass. It also facilitates annealing, because a bottle will stand much 
more severe usage without breaking and the glass does not require 
annealing to be conducted in as careful a manner as in the case of 
other glass. An alumina glass is also somewhat harder and a little 
more brilliant than ordinary glass. 

One of the disadvantageous properties of alumina is that it de- 
creased the fusibility of the glass. Likewise it increases the viscosity 
when present in amounts exceeding 3%. Also glass containing 
alumina does not mix well with other glass to form a perfectly 
homogeneous mass, free from cords. Care must, therefore, be ex- 
ercised in using such glass as cullet. 

The above observations leads one to conclude that for all ordinary 
varieties of glass the small amount of alumina usually present in 
glass sands has no injurious influence on the glass, and if anything is 
beneficial. Frink^^ cites an interesting case where a sand containing 
7.26% AL^Og and 0.31% Fe^O^ gave a class of superior physical 
properties to that of sand containing but 0.68% of ALOg and FCgOg 
combined. The glass made from the first sand contained 70.51% 
SiO^, 5.98% Al2O3,.0.23% Fe.Og, 9.57% CaO, 0.81% MgO and 12.87% 

15. TransfictionR Amprican fVramlc Society, Vol. IR, 1913, pp. 700-727. 

16. Trnnsactlonii Amerlcau Ceramic Sodoty, Vol. 11, 1909. pp. 99-102. 

17. Transactions American Ceramic Society, Vol. 11, 1909, pp. 296-319. 


NajO, while that from the second or purer Bsntd contained 72.01% 
tiioj, 1.81% AI2O3 and FegO, combined, 12.48% CaO, 0.41% MgO 
and 13.21% NajO. The former showed an increased resistance to 
tension 8.3% in modulus of rupture, and had a higher lustre. It 
had a remarkable power of resistance towards alkalies and was 
not attacked as readily by acids. It also annealed readily, but was 
somewhat more susceptible to changes in temperature and had a 
considerable higher viscosity at given temperatures. 

Iron occurs in glass sands both in the ferrous and ferric condi- 
tions. It is usually present as limonite (Fe2(OH)6Pe,Oa), hematite 
(FejOg), or magnetite (Pe204), but sometimes such minerals as Umen- 
ite, hornblende and chlorite, present in some quantities in the sand, 
will also contribute towards its iron content, Limonite usually 
occurs intimately mixed with the kaolinite or other hydrated alum- 
inum silicates, forming the small amount of clayey material asso- 
ciated with the sand, or thin films of limonite sometimes coat the 
little sand grains or fill minute crevices in the grains due to frac- 
turing. Where the iron is present as limonite mixed with clay it 
may be largely removed by washing. Sands that are cream colored, 
yellowish brown or brown, contain limonite, the shade of color 
depending upon the amount of limonite present. Hematite colors a 
sand reddish brown. The color of the sand cannot always be taken 
as a criterion of the amount of iron present, however, as a light 
colored or nearly white sand may contain sufiScient magnetite or 
iiraenite to make tlie iron content higher than that of a yellowish 
brown Hand containing the iron in the form of limonite. When iron is 
present largely as magnetite or ilmenite it may be removed by mag- 
netic separation. 

Iron is the most detrimental impurity found in glass sands on 
account of its coloring effect on the glass. Ferrous iron gives the 
^lass a bluish-green tint. Because nearly all glasses contain at least 
traces of iron, when glass is viewed through a thick section it always 
has a greenish cast. The color becomes more intense as the per- 
centage of iron increases, so that ordinary bottle glass which contains 
a relatively high percentage of iron is often spoken of as green glass. 
Ferric iron, on the other hand, gives the glass a yellow tint, which 
is not nearly as noticeable. Certain decolorizing agents are often 
added to glass batches to neutralize these coloring effects of the iron, 
when it is present in only small quantities. These are described in 
a later paragraph. 

The percentage of Fe20, which is permissable in the sand depends 

upon the kind of glass which is being manufactured. In the case 

of optical and the best grades of crystal or lead flint glass, if the 

other raw materials are very pure, the percentage of FCnOg in the 

^nd may run as high as 0.02 according to Dralle. Rosenhain 


places the upper limit as high as 0.05%. For plate glass Dralle 
gives the upper limit as 0.2% when the glass is viewed by trans- 
mitted light and 0.1% where it is used for mirrors. In the case of 
window glass, where thinner sheets are employed, and the glass is 
viewed by transmitted light, the iron content may run up to 0.5%, 
but should not exceed this figure. This is also the upper limit per- 
missable for white bottles. For ordinary green and brown bottles 
Bands tunning from 0.5% to 7.0% FegOj are often used. 

A rough insight into the amount of iron present in a sand may be 
obtained by taking 5 to 10 grams of the sand and warming with 
not too concentrated hydrochloric acid solution. This acid is then 
filtered off and treated either with a solution of potassium ferrocy- 
anide or with potassium sulphocyanide. In the former case a blue 
precipitate will be obtained while with the latter the solution will be 
colored red if iron is present. The intensity of the color gives one 
an approximate idea as regards the amount of iron present in the 
sand. An exact determination, however, is not possible by this means 
because some of the iron may be present in the sand in such combina- 
tions with other elements as not to be soluble in hydrochloric 
acid. It is always necessary, therefore, in order to get the exact 
amount to make a regular quantitative analysis of the sand, either 
by fusing it with about four times its weight of equal amounts of 
fodium and potassium carbonate, or treating it with hydrofluoric 
j'cid to which a few drops of sulphuric acid have been added. The 
exact methods of procedure are given in standard books on inorganic 
quantitative analysis. 

Magnesium and calcium oxides are frequently found to be present 
in minute quantities in glass sands, usually occuring in the sand 
as carbonates. In most sands used for glass making, however, the 
quantity is so small as to be negligible. They have no detrimental 
influence on the glass. Lime is a part of the composition of most 
of the ordinary glasses of commerce. Magnesia is much more apt 
to be introduced into the glass in appreciable quantities through 
the limestone employed as a ^raw material for lime than through 
rhe sand, and its effect on glass is, therefore, taken up under that 

Where sand is used for the manufacture of the better grades of 
glass, such as optical, lead flint, lime flint and plate glass, it is 
nsually dried artificially before it is introduced into the glass batch. 
For the cheaper grades of glass such as window and ordinary green 
bottle glass, wot sand is often employed. Where it is necessary to 
keep a close chock on the composition of the batch dried sand alone 
Mhould be used, as the percentage of moisture in wet sands is apt 
to vary greatly even in different parts of the same shipment of sand, 
making numerous determinations of moisture content, at frequc 


intervals, necessary. Most of the water in sands is present as little 
tilius adhering to the grains. A little, however, may occur in chem- 
ical combination with other elements in the form of such minerals 
as kaolinite, limonite, chlorite, or muscovite. 

A small amount of titanium oxide is found in practically all glass 
sands, whenever a determination of this element is made. This 
varies from a few hundredths to a few tenths of a per cent. Most 
of it is present in the form of little needles of rutile (TiOj) which 
occur as inclusions in the quartz grains, especially in those which 
have been originally derivefl from igneous rocks. A little of it may 
also be present in the form of small grains of ilmenite (FeTi),Oa, 
or tilanite (CaSiTiOg). The writer has not come acro^ any data 
showing what effect titanium has on glass. The very small amounts 
usually present in glass sands undoubtedly are negligible as far as 
;iny influence on the properties of the glass are concerned. 

Frink'^ has called attention to the fact that small grains of round 
pebbles, sometimes referred to as "ganister" by the glass men, when 
present in appreciable quantities produce small white stones in the 
glass because the temperature of the glass furnace is not suflBciently 
high to cause them to go into solution in the molten glass. According 
to Frink these pebbles usually consist of silicates of magnesium and 
lime, or lime and alumina. They are silicate minerals which were 
present in the original rock from which the sand was derived, which 
were not completely decomposed in the process of weathering and 
were not sorted out during the transportation and deposition of the 
sand. Such pebbles can be distinguished readily when the sand is 
examined under the microscope. 

The size and shape of the grains is also a factor of some im- 
portance in determining the value of a glass sand, but usually this 
k only a matter of secondary consideration compared with the chem- 
ical composition of the sand. In regard to the most desirable size 
there is still considerable difference of opinion. Many hold that 
the majority of the grains should not pass a sieve having 120 meshes 
uer linear inch. That is the majority of the grains should be over 
0.136 millimeters in diameter. On the other hand the bulk of the 
sand should pass through- a 30 mesh sieve, that is the grains should 
have a diameter of less than 0.64 millimeters. These sizes, how- 
ever, are not adhered to by all glass manufacturers, and when 
'he sand is otherwise nearly chemically pure variations are per- 
missable. One glass manufacturer in Pennsylvania has been using 
<and pulverized so as to pass an 100 mesh sieve in the manufacture 
of the finer grades of his lead flint for cut glass articles, holding 
that the sand thus reacts more readily ^ith the other raw materials 

1R. Glass Workpr. Vol. 81, 1012. No. 9, pir. 2. 


of the batch, as the quartz per unit of weight oflfers a relatively 
greater area to be acted upon than in the case of coarser grains. 
It is* doubtful, however, whether enough is gained in this way to 
pay for the extra cost incurred by having the sand pulverized to 
this fineness. Thorough mixing of the sand with the rest of the ma- 
terials of the "batch also becomes more difficult when it is in such a 
finely divided state and when the sand is too fine there is apt to be 
a greater loss due to particles being carried away by the draught. 
This holds true especially in the case of tank furnaces. When the 
grains are uniformly larger than will pass a 30 mesh screen more 
time is required to have them react with the other materials of 
the batch and go into solution in the resulting molten glass. This 
necessarily decreases the output of the furnace. 

The determination of the size of the grains of sand is made by 
passing a weighed amount of sand through a series of sieves arranged 
in regular order, with the coarseet mesh at the top. One hundred 
grams is a convenient amount to take as it obviates all calculations, 
the weight of sand remaining on each screen being the percentage 
by weight of the grains which have a diameter between that of 
the screen opening they are on and the next screen above. In 
making determinations of the size of sand grains the writer re- 
commends the use of the Tyler Standard Screen Scale Sieves, manu- 
factured by the W. S. Tyler Company of Cleveland, Ohio. This 
screen scale has as its base an opening of 0.0029 inches, or 0.074 
iiiillimeters, which is the opening of a 200 mesh, 0.0021 wire stand- 
ard sieve as adopted by the United States Bureau of Standards. 
The openings increase in size from that upwards in the ratio of 
the square root of two, or 1.414. Unless some such standard is 
t'dopted it is very difficult to compare size determinations made by 
different individuals using different screens. The above screens were 
used in all size determinations made by the writer in connection 
with the preparation of this report. 

It was formerly thought that the sand grains should be sharp and 
f^ngular to give the best results. With the opening up of deposits 
of exceptionally pure quartz sands and sandstones in the Mississippi 
Valley region, around St. Louis, Missouri, Ottawa, Illinois, and in 
certain areas in Michigan, which are made up of well rounded grains. 
i+ h?^s been fornd that these sands give excellent results in the case 
of ordinary varieties of cjlnss, including lime flint, plate and window 
glass, and also lond flint for fine ware. The chemical purity of the 
glass used is the important factor. In this coTinection it mnv be 
said, however, that in the case of two sands of like purity and simlhir 
«ize of frrains, the one in which the <Trains nre shi^^p n^^ n'^^r'i^ 
is somewhfit more dpsirnble thnn th^ one made of well rounded 
Drains, hecnuse for the snme size grain in volume and weight the 
angular grain will have a greater area of surface exposed to the 


action of the other ingredients of the glass batch when melting oc- 
curs, and will therefore react with them more readily. 

Plates IV to XI show comparisons of shape of different sized 
grains in a sharp, angular sand, like that produced at the Keystone 
Works of the Pennsylvania Glass Sand Company, near Mapleton, 
Pennsylvania and a well rounded sand like that produced by the 
Wedron White Sand Company, of Ottawa, Illinois. The results of 
the size determinations of these two sands were as follows: 

Percentage of Sands Passing Through Different Screens. 

Remaining on 20 mesh screen, — 

Remaining on 28 mesh screen, but through SO mesh, . 
Remaining on 3S n^esh sen en, but through 28 mesh. 
Remaining on 48 mesh screen, but through 35 mesh, 
Remaining on ft'i mesh serpen, but through 48 mi-sh. 
Remaining on 100 mesh screen, but tlirougb 96 mc. h. 
Remaining on 150 mesh screen, but through 100 mesh, 
Remaining on 20O mesh screen, but through 150 mesh. 
Remaining on 200 me«h, — 

No. 1. 


No. 1. 




















Deposits of glass sansd are found in nature in which the individual 
grains are not held together by a bond or cement of any kind, but 
occur simply as bodies of loose, unconsolidated material. Often, how- 
ever, the individual grains are held together by a bond, forming what 
is called a sandstone. In the latter case it is necessary to crush the 
rock, so that the bond between the grains becomes severed and the 
rock crumbled to a loose sand. For making glass sand only such 
sandstones are desirable as break comparatively readily along the 
bond between the individual grains and not across the actual grains 
themselves. Very thoroughly cemented sandstones or quartzites are 
not desirable, as the process of crushing them to the desired size is 
an expensive one and much material of undesirable sizes results. 

The method of preparing a glass sand from sandstone is taken 
up first. There are two methods in common practice. One is to 
crush, wai^-h, dry, and screen the sand, while the other is simply to 
crush and screen. The former method is used in the preparation 
of the better grades of sand used in the manufacture of lead flint, 
lime flint, and plate glass, while the latter method is occasionally 
used for the cheaper grades of sand used in the manufacture of win- 
dow glass and ordinary bottle glass. 

By washing the sand the fine clayey material, consisting largely 
of kaolinite or some other hydrated aluminum silicate, with usually 
i{ little limonite mixed with it, is removed from the sand. This oper- 

Tig. 2. Sand erains of a- 

cliinl Hhikf TyiH> Cninii.T. Unilt by L.>\vislij«-[i Fmiiiilry nnii Mndiine C.i. 

I'LATK Xlil. 


atloiiy therefore, reduces the alumina and ferric oxide content of the 
band. When there are appreciable quantities of limonite mixed with 
the clayey material, therefore, it is important that the sand should 
be washed carefully. If on the other hand the iron is present in the 
sand as magnetite or some other mineral which occurs as little 
grains, or if the quartz grains themselves are coated with a closely 
adhering film of iron oxide, washing does not improve the quality 
of the sand to any extent. 

In the wet treatment the sandstone, as it comes from the quarry, 
is first passed over a grizzly, consisting of a series of parallel 
steel rails placed about two inches apart, in an inclined position. 
The fine material drops into the slots between the rails while the 
the larger pieces pass over into a jaw crusher. The Blake type of jaw 
crusher is the one usually employed. Plate XII shows some of 
the various styles of Blake type rock crushers commonly used in 
Pennsylvania. A 20x12 inch crusher handles from fourteen to twen- 
ty-five tons of material per day, depending upon the nature of the 
rock crushed, reducing it down to about three inch diameter. It 
works at a speed of 250 revolutions per minute, and requires from 15 
to 25 horse power to operate it. 

The material from the jaw crusher an<d that which passes through 
the grizzly goes next to a chaser mill or grinding pan. Plate XIII 
illustrates several chaser mills and grinding pans designed for this 
purpose. Thes6 mills consist of circular steel pans, varying in dia- 
meter from 6 to 9 feet, in which two heavy steel rolls or mullers, 
mounted on horizontal axles, revolve. The pan itself is stationary. 
"Water is fed into the pan and the material as it is crushed passes 
out through screens at the sides of the pan. Two opposite ends of 
the pan are usually perforated for this purpose. The capacity of 
a mill varies with the diameter of the pan and the liardness of the 
material treated. A nine foot pan will handle anywhere from 100 
to 250 tons of material per day of ten hours, depending upon the 
readiness with which the sandstone crumbles under the mullers. 
For a nine foot mill the rolls usually have a 12 inch face, and 
weigh from five thousand to six thousand pounds each. They re- 
volve about the central shaft at from 30 to 33 revolutions per minute, 
sind require about 35 horse power to operate them. 

From the chaser mill the material goes to a revolving screen. 
Sometimes only one screen is used, sometimes two, placed at opposite 
sides of the pan. Figure 1, plate XIII, shows these screens in place. 
They have a diameter of from 7 to 8 feet and a 24 to 36 inch face. 
They revolve about a central spindle at about fifteen revolutions per 
minute. These screens are made of brass wire with from 10 to 12 
meshes per linear inch. The undersize material passes through the 
screen to the washer, while the oversize is returned to the chaser 


mill. Occasionally when there is apt to be considerable coarse ma- 
terial present the sand is run through two of these revolving screens, 
the first one having only about six meshes per linear inch, while 
the second has twelve. This is done to protect the finer screen with 
the smaller diameter wire from too rapid wear 'by abrasion from 
the course particles of rock. 

From the revolving screens the undersize material goes to the sand 
washers. These consist of inclined wooden boxes or troughs, ten 
to twelve feet long and 18 to 22 inches wide on the inside. In these 
troughs are cast iron rotating screw conveyors, with wide blades, 
which carry the sand from the bottom to the top of the troughs. 
Plate XIV shows the appearance of these screw washers and illus- 
trates the way in which they are set up. About one horse power 
is required to operate each screw. The washers are set up in bat- 
teries of two, three, four, five, and sometimes six washers each. 
They may be set up either parallel to one another or in tandem. 
Plate XV shows three batteries of three screws each arranged in 
tandem. The troughs are inclined at angles varying from 18 to 20 
degrees from the horizontal. The sand enters each washer at the 
foot, while water runs in at the head. The revolving screws thus 
carry the sand up the trough against the stream of water, which 
carries away with it the fine clayey material present in the sand. 
When the sand reaches the head of one washer, where they are ar- 
ranged in parallel, it is dumped into a trough and is carried to 
the foot of the next washer by a stream of water. It passes on up 
this washer in a similar manner, and thus on through the other 
washers of the battery. Where the washers are set up in tandem 
they are so arranged that one washer discharges into the lower end 
of the next oncj, and so on through the series. 

A plant with a nine foot grinding pan requires at least 150 gallons 
of water per minute. In some plants 400 to 600 gallons are used. 
An adequate supply of water, therefore, is an absolute necessity for 
a washing plant of this type. 

If the sand is to be shipped wet it is ready for the cars after 
leaving the washers. If it is to be dried it goes to the draining 
sheds, where the excess water is allowed to run off. The sand from 
the washers is discharged onto a rubber conveyor belt, inclined at 
the end near the washer and horizontal at the end over the draining 
floor. The belt runs near the roof of the draining shed and the 
sand is allowed to drop from it so as to buiid up large cones, reach- 
ing from the floor to the belt. These sheds ordinarily have suffi- 
cient length to permit discharging at various points along the belt, 
and thus several of these cones of sand may be built up. The sand 
is usually allowed to drain at least twelve hours. 


•J V 

J J ' 

ViR. 1. Ciininii-r siyl^ "l-- lirycr. Sc-lf-o..iitiLiur,l. with .-ilmust fm 

Fig. 2. Ciinimi-r drjc-r. Somi-si'lf-eontiiiuod ly|ic, wiili iliw' fiiii 


After the surplus water has been drained off, the sand is ready 
for the dryer. It is usually shoveled by hand onto a bucket elevator 
which carries it to a horizontal belt conveyor running to the 
dryer. This bucket elevator is so arranged that it can be moved 
about from place to place in the draining shed. 

There are several types of dryers in use. Of these the steam 
dryer is the most recent invention and is gradually replacing the 
others. Steam dryers are usually built in sections about 20 feet 
long, 8 feet wide and 6 feet high, with hopper shaped bottoms. 
The walls of thjB dryer are built of ordinary red brick. Inside are 
horizontal steam pipes resting on inverted angle irons. These pipes 
are arranged in tiers one above the other, and are placed closer and 
closer together towards the bottom of the dryer. The sand is dis- 
charged onto these pipes from a belt conveyor running over the 
dryer, and gradually drops down between them and finally is dis- 
charged onto another belt conveyor at the bottom of the dryer. The 
pipes are heated by passing steam through them. This evaporates 
the water in the sand. The resulting steam and damp air accumu- 
late under the angle irons on which the pipes rest, and are drawn 
off by means df an exhaust fan. 

Direct heat dryers are also used in the drying of sand, although 
they are no longer as popular as formerly, and in many plants are 
being replaced by steam dryers. The Cummer Salamander Type of 
Direct Heat Dryer, manufactured by the F. D. Cummer & Son Co. 
of Cleveland, Ohio is the style of this type of dryer most frequently 
found in Pennsylvania sand plants. A Cummer dryer consists of 
a revolving steel plate cylinder, carried on steel tires, which run 
on steel rolls at each end. The rolls are supported on structural 
steel foundation plates. Compound gearing is used for revolving 
the cylinder, with a reduction of 10 to 1. Figure 1, plate XVI 
shows the Cummer style "F" dryer, self contained type, with ex- 
haust fan. Figure 2 shows the semi-self-contained type. The sala- 
mander type is very much similar to this, the only difference being 
that the internal construction of the cylinder is modified to suit 
it for drying sand which is not necessarily injured by overheating. 
The setting is also different. In this dryer the wet material is fed 
continuously into the dryer at the one end, through the feed spout 
"A'*, and is discharged at the rear end dried. The heated gases 
resulting from combustion in the furnace pass into a large comming- 
ling chamber which extends the entffe length of the dryer cylinder. 
This cylinder, which revloves slowly, has a great many large square 
openings in it, each of which is covered with a cast iron hood or 
cap, as shown. A suflScient number of hoods are put into each cyl- 
inder to allow about three fourths of the heated air and gasses to 
enter the cylinder. The balance of the heated air and gasses enter 


the cylinder through the rear - end. The result is there is com- 
paratively little circulation at the rear end of the cylinder where 
the material is practically dry, and consequently there is little or no 
dust hlown out through the stack. 

The fan, which is located at the front or feed end of the dryer, 
draws the products of perfect combustion from the furnace into the 
commingling chamber, also air through the registers in the side 
walls of the dryer, which reduces the temperature towards the rear 
end of the dryer cylinder. The same fan draws the heated air and 
gasses at different temperatures from the commingling chamber into 
the cylinder through the hoods into direct contact with the material 
being dried. The highest temperature gasses enter through the 
I'ront hoods in contact with the wet, cold material as it enters the 
cylinder. The material immediately on entering the cylinder com- 
mences to dry as it travels rearward towards the discharge, rapidly 
becoming more dry, the temperatures of the heated air and gases are 
relatively lowered by the cold air coming in through the registers 
in the side walls of the dryer. The drying material is constantly 
cascaded in the cylinder as it travels towards the rear or discharge 
end of the cylinder in the opposite direction to the heated air and 
gases. The air, gases and moisture pass into the atmosphere from 
the cylinder through the fan. For drying glass sands coke must be 
used as fuel. Where ordinary bituminous coal is used there is apt 
to be a coat of carbon formed on some of the sand grains, due to 
imperfect combustion. This is not permissable where the sand is 
to be used for glass making purposes. 

Another type of direct heat dryer occasionally used consists of a 
brick stack about thirty or forty feet high. At one side of this 
stack is a fire box, provided with artificial draft, air being forced into 
the fire box by means of a blower. A bucket eleyator carries the 
sand to a point near the top of the stack, down which it is allowed 
to drop. It is discharged at the bottom of the stack by means of 
a screw conveyor. The moisture in the sand is driven off by the 
heat of the rising gaseous products of combustion through which 
it falls. Coke must be used as a fuel for the same reason as in the 
case of the Cummer dryer. 

One of the objections against the direct heat dryers is, that if 
they are not carefully watched the sand is apt to become heated to 
a temperature that sets fire to any wood work with which it comes 
in contact. Disastrous fires have resulted from this cause. It is 
also claimed by those who have installed the steam dryers that the 
cost of operating them is less. 

After the sand has been dried it is screened. The size of screens 
varies in different plants, sizes from 14, 16, 18, 20, to 22 meshes per 
linear inch being employed. Eighteen meshes per inch is probably 


Fig. 3. No. 24 Pulvcriiser, with top removed. 


WiKrr J.'t S:iii(t WusIiImk I'litut, os miiriiifii<.-tiir>'il by Koliiitti' uiiil K<h' 


the most common size used. After the sand has been screened it 
is elevated to the storage bins, ready for shipment. 

Some of the larger and more modern sand plants of Pennsylvania 
are capable of producing three hundred tons of dried' sand per 
day, and cost in the neighborhood of ?45,000 to erect, according to 
figures quoted by the Lewistown Foundry and Machine Company. 
This includes all the equipment and buildings, also erection costs. 
Phillips and McLaren of Pittsburgh estimate that the machinery 
for turning out two hundred and fifty tons of wet sand per day, 
including a 20" x 12" Blake crusher, a nine foot grinding pan, a 
revolving screen, and the necessary sand washers, cost about $4,000. 
This does not include the wooden boxes for the washers. 

Thomas Carlin's Sons Company of Pittsburgh, furnished the writer 
with the following cost data for erecting a 100 ton daily capacity 
wet sand plant. 

Electric Power. 

1 8' pan, without pulley and pinion shafe. but with double screens. $1,350 00 

1 20"xl2^ crusher 600 00 

5 Screw washers. WxW, _. 600 00 

1 9'x32^ revolving screen 250 00 

1 Elevator. 250 00 

Line shaft, pulleys and bearings, 187 00 

Belts. 185 00 

1 50 H. P. 220 volt. 3 phase, 60 cycle, 695 R. P. M. motor 600 00 

1 30 H. P. 220 volt. 3 phase, 60 cycle. 865 R. P. M. motor, 415 00 

Erecting machinery, including transportation and board of men, . 500 00 

Lumber and.carpenter labor 650 00 

Foundation bolts and pipe, — __ 100 00 

Engineering and drafting 100 00 

Steam Power. 

1 8' pan $1,300 00 

1 20^x12" crusher - 600 00 

5 Screw washers 600 00 

1 8* screen, 200 00 

1 Elevator, _ 210 00 

Line shaft, pulleys and bearings 222 88 

A Rubber belt. I Fithercan be used I ^^ H 

1 Ruboil belt. S ^^^^^^^^° DC usee, j 249 26 

1 100 H. P. engine , £69 00 

1 Boiler and fittings. 600 00 

(Tt mnAt be trnderatood these flgtirese are aa of the time flren. and subject to conitant chanfea 
In pricea of material and auppUea.) 

A Number 1, Semi-self contained Cummer Salamander Dryer of 
12 to 15 tons capacity per hour costs from §2,400 to $2,500, complete. 
The iron work costs about |2.200. It requires 18,000 red brick 
and 2,500 fire brick to erect, and about 10 H. P. are required to 
operate it. 

In the above estimate no figures for the erection of bins and suit- 
able buildings to house the machinery are included. 

Instead of the chaser mill or grinding pan for crushing the sand- 
stone other types of disintegrators are occasionally used. Figure 1, 
plate XVII shows the internal construction of the style "A", triumph 
Disintegrator, manufactured by the C. O. Bartlett and Snow Co., 
of Cleveland, Ohio. The style "B" machine, which is adapted t 


breaking up sandstone of the type suitable for glass sand, is of similar 
construction, but is heavier, and made of a better grade of material. 
The two sets of spokes, which are made of high grade Swedish 
iron, revolve in opposite directions. The sandstone as it falls be- 
tween them is caught and crushed. A No. 2 disintegrator of this 
type, having a diameter of 36 inches and a speed of 400 revolutions 
per minute, has a capacity of 30 tons of sandstone per hour. The 
Warren Silica Company, at Torpedo, Penna. uses such a disin- 
tegrator. They find, however, that with the kind of rock they are 
crushing they can only get a capacity of 20 tons per hour. 

The American Pulverizer Company, of East St. Louis, also manu- 
facture a pulverizer designed to crush sandstone to sand. The 
grinding is accomplished by means of revolving rings, weighing 
about 27 pounds each, made of manganese steel or semi-steel chilled 
iron which are placed between grate bars of manganese steel. Th^ 
rings and bar» do not touch, but as the sandstone is carried between 
them it is crushed by impact. The machine is operated at a speed 
of 600 revolutions per minute. Figures 2 and 3, plate XVII, illus- 
trate the construction of this pulverizer. The material should be 
reduced to pieces not over two inches in diameter in a gyratory or 
jaw crusher before it is fed to the pulverizer. A No. 24 Pulverizer 
of this type will reduce about 15 to 20 tons of sandstone to sand 
per hour. 

One of the diflBculties encountered in using disintegrators and pul- 
verizers of the above types to crush material which is as hard as the 
quartz grains of sandstone is the excessive wear of the grinding 
parts. This makes it necessary to replace them at frequent inter- 
vals. Some iron is thus introduced into the sand in this manner, 
which of course is another objectionable feature, especially in the 
case of the better grades of sand. ^ 

For washing sand the Schutte and Koerting Co. of Philadelphia 
have designed a water jet and washing device, illustrated in plate 
XVII r, which operates on a different principle from that of the 
screw washer commonly used for this purpose. This consists of a 
series of iron boxes B, placed in one or more rows, or in a circle, 
with a water jet eductor A installed in each box. In the first box 
the sand which is to be washed is admitted at I, and at the same 
time is stirred by means of a clean water jet at X. The sand 
eductor is operated by means of clean water taken from pressure 
pipe P and lifts . the sand to the second box. As the sand is 
heavy it drops to the bottom of the box, while the water mixing 
with the clayey material on account of the violent stirring rises and 
overflows near the top. In this way there is obtained a cleaning 
of the sand by the use of clean pressure water only, without the 
assistance of any mechanical means. It is desirable that the water 



be as clean as possible and the pressure at the eductor should be 
under a head of 30 to 40 feet. These boxes are made in two sizes; 
No. 1 having a capacity of 140 cubic feet of sand per hour and cost- 
ing f 120 per box, and No. 2 having a capacity of 210 cubic feet per 
hour costing |200. Two and one half cubic feet of water are required 
per cubic foot of sand. The number of boxes through which it is 
necessary to pass the sand depends upon the amount of clayey ma- 
terial present. 

When the sand occurs as loose, unconsolidated material, the neces- 
sary plant to prepare it for the market is much simpler. No jaw 
crusher, chaser mills^ grifiding pans, or other crushing devices are 
necessary, the sand going directly from the quarry to the washers. 
It may be loaded into cars and thus transported to the plant, or if 
there is sufficient slope from the quarry to the washers, it may be 
washed into sluices by means of a stream of water played against 
the sand bank and thus transported. Sometimes if the bottom of 
the sand deposit is below the level of the washer, it is first washed 
into a sump by means of a stream of water, and then pumped through 
pipes to the washer by means of a sand pump. Plate XIX shows a 
No. 5 Nye Sand Pump, manufactured by the Nye Steam Pump and 
Machinery Co. of Chicago, installed in a saud pit. A pump of this 
type, with a six inch suction and five inch discharge pipe, handles 
ninety tons of sand per hour. The sand is first blasted down from 
the face and is then washed by water jets to the pump, which forces 
the sand and water through pipes to the washer. 

Sometimes the cheaper grades of glass sand are not washed, the 
sandstone being simply crushed and screaned. When this method 
of preparation is used a different type of grinding pan is employed. 
Plate XX Dlustrates types of dry grinding pans desinged for this 
purpose. In a pan of this type the mullers or rolls do not revolve 
about a central shaft, although they turn about the horizontal axis 
on which they are mounted, but the pan itsel| is rotated. The rolls 
run on false plates which may be renewed when they are worn, while 
the outer portion of the bottom of the pan consists of screen plates 
through which the crushed material passes. After the material has 
gone through the grinding pan it is conveyed to a revolving or shaking 
screen, from which the undersize is conveyed to storage bins, stock 
piles, or directly to the cars, while the oversize goes back to the 

Glass sands occasionally occur in nature in which most of the 
iron is present in the form of little grains of magnetite (Fe304) or 
ilmenite ( (FeTi)o03). Both these minerals are attracted by a mag- 
net and, therefore, magnetic separation can be resorted to to lower 
the iron content of the sand. Some iron also gets into the sand 
from the machinery. Quartz is a hard substance and as the wearing 
parts of the machines in which sandstone is crushed are of iron, fine 


particles of iron get into the sand through abrasion. A magnetic sep- 
arator removes these also, as well as the magnetite and ilmenite which 
may be present. Plate XXI shows a magnetic separator manufactured 
by the Dings Electro-Magnetic Separator Co., of Milwaukee, which 
may be used for this purpose. The sand is charged into the hopper 
at the top and passes down a vibrating conveyor under the magnet, 
which picks out particles of iron, magnetite or ilmenite which may be 
present and carries them beyond the sides of the conveyor where 
they are dropped into a hopper. The writer does not know of any 
sand plants where magnetic separation is employed, and of only 
one glass factory where the sand used is treated in this way. 

Kiimmel and Gage" have called attention to the fact that many of 
the minerals containing iron that are ^pt to be present in glass 
sands pass* an 80 mesh sieve. Cleansing the sand by screening there- 
fore is possible. They carried on experiments in the laboratory with 
two samples and obtained the following results: 

Screening Tests on Sands. 




First Sample. 

Second Sample. 

B«fore After 
Screening. Screening. 





1 .117 










These figures show that they were able to reduce the content of 
iron to one third, of titanium to one fifth, and of alumina to one 
third or less of the amounts originally present in the sand. As far 
as the writer knows this method has never been tried out in actual 
practice, and it appears very doubtful whether it could be carried 
on commercially, as almost perfect screening would be required 
to make it successful and a considerable percentage of fine quartz 
sand would also be lost, as inspection of screen analyses of glass 
sands will show. 

Tscheuschner-® describes a rather expensive method for purifying 
yellow sands which contain considerable quantities of limonite. For 
this purpose 64 parts of sand are sprinkled with 8 parts of water, 
to which 3 parts of salt and 2 parts of concentrated sulphuric acid 
have been added. The whole is placed in a container lined with lead, 
and allowed to stand for several months. The iron gradually goes 
into solution as the chloride. Finally the sand is carefully washed 
and drie<l. This method was at one time used in Europe in locali- 
ties where pure white quartz sands were not available, but with 

19. CJeoloiflciil Surrey of New Jersey. Annual Report for 1906. pp. 77-96. 

20. Handbnch der Glasfabrikatlon, 6th. ediUon, Weimar, 1885. 



improvements in transportation facilities it became obsolete* Olass 
manufacturers have never resorted to such methods in this country 
on account of the ease with which high grade quartz sands that re- 
quire no such expensive treatment may be obtained. 

Other sources of silica besides quartz sand have be^i made use 
of in the past in the glass industry, but at the present time their use 
has been practically discontinued. One of these is massive quartz^ 
0i:curing as a vein filling in fissures in the earth's crust. Before this 
quartz can be used it must be crushed, which is an expensive opera- 
tion. It was, therefore, early in the history of the glass industry 
replaced by quartz sands in which the grains are already of the re- 
quired fin^iess. 

An attempt was recently made^^ to revive the use of ground 
quartz as a substitute for glass sands by manufacturers at San 
Francisco and Los Angeles, California, because deposits of high 
grade glass sands have not as yet been discovered on the Pacific 
Ck)ast, while massive quartz, occuring as filling in fissures, is abund- 
ant. The attempt, however^ was a failure. It was found cheaper 
to import glass sand from other portions of the United States than 
to crush the massive quartz to the necessary fineness. 

Flint was also employed at one time as a source of silica in 
glass. T^e term ^^flint glass'' which still survives in the glass 
industry, was derived from this usage. Flint consists of an intimate 
mixture of quartz and opal. It has a dark gray to black color and 
is extremely compact, so that it has the appearance of a homogen- 
eous substance. The fracture is conchoidal, and chips have a trans- 
lucent edge. The coloring matter consists of organic material and 
disappears when the chip is heated before the blow pipe. Flint 
occurs in chalk, in the form of irregular nodules or concretions, 
which vary widely in size. When examined under the microscope 
it is often found to consist of the hard, siliceous parts of various 
organisms, chiefly sponges and radiolarians which lived in the seas 
in which the limestones were deposited. The silica was first de- 
rived from the sea-water by these organisms and when they died 
their skeletons accumulated on the ocean floor, together with the 
more numerous calcareous skeletons of other organisms which fur- 
nished the material for the chalk. Afterwards, this silica again 
went into solution and was chemically deposited around certain 
centers, and in certain places when favorable conditions obtained 
thus forming the flint nodules and concretions as they exist today 
in the chalk deposits. 

Such concretions are often abundant in the chalk beds along 
thp northern coast of France and the southern coasts of England, 
and in the Danish Isles. They are there freed from the chalk by 

21. Mfntny and Sdentlflc PreM, Oct 16. 1018, pp. 690-eoo. 



wave erosion and accumulate along the beach^ where they were 
formedly obtained for glass manufacture. They are no longer gath- 
ered for this purpose, however, as they have become much more 
valuable as pebbles for grinding in tube mUls, to which their use 
is now restricted. Quartz sands are a much more desirable and 
cheaper source of silica and have, therefore, replaced them . as a 
source of silica even in those localities in Europe where flint was 
formerly used. 

Before opening up a new glass sand deposit and install- 
ing the necessary machinery to prepare the sand for the mar- 
ket, a number of factors upon which the success of the enterprise 
will depend must be taken into consideration. Of course it is first 
necessary to determine whether the sand stone or sand is of suffi- 
cient purity to allow it to be employed in the manufacture of glass. 
The size of the deposit must next be taken into consideration. A 
careful investigation should be made to determine whether it la 
sufficiently large to warrant the investment of the necessary capi- 
tal for buildings, machinery, etc., which are needed to operate a 
glass sand plant. 

Variations in the texture or composition of the sand or sand- 
stone, both across and along the bed should be looked for, as these 
often occur due to slight variations in the conditions und^r which 
the sand was deposited. Portions of a bed thus often become too high 
in iron to be used for glass manufacture, and have to be sorted out 
from the sandstone, which increases the cost of production. Like- 
wise, lenticular shaped masses of conglomerate often occur in beds 
of sandstone. On account of their pebbly nature they also have to 
be sorted out. 

Attention has already been called to the fact that the sandstone 
should be rather friable and the rock should break down fairly read- 
ily along the cementing material between the grains and should not 
be of such a nature as to break across the grains rather than along 
the bond. 

The geologic structure of the deposit must also be considered. 
If the beds are inclined or tilted it must be remembered that they 
can only be followed down on the dip a relatively short distance 
until underground mining methods become necessary. This can be 
done profitably only under very special conditions, when the sand 
deposit is an exceptionally pure and extensive one, and mining con- 
ditions are favorable. When the beds are horizontal, or nearly so, 
the amount of overlying material which it is necessary to strip must 
be determined. There may be so much of it that the deposit cannot 
be worked at a profit. 

Where the sand is to be washed, the water supply must be ex- 
amined. Sometimes this factor is neglected and sand plants are 

reed to shut down during the summer and early fall on account 


of a lack of sufficient water to wash the sand. This may mean very 
serious loss. 

The nearness of a market and transportation facilities are of ex- 
treme importance. Sand is a bulky material, sold at a comparatively 
low price, so that the margin of profit is small. The distance of 
various sand deposits from a certain market, therefore, is a big 
factor in determining which ones are able to compete for that mar- 

Boric Acid. BsOa. 

Boric acid is sometimes used as a partial substitute for silica in 
glasses manufactured for special purposes. By replacing part of 
the silica of a lime flint glass with boric acid, a boro-silicate crown 
is obtained which is used for optical glass, thermometer tubing, 
and laboratory ware. When boric acid replaces part of the silica 
in a lead flint glass a boro-silicate flint is obtained which is also 
used for optical purposes and for the manufacture of enamels and 
"strass" for imitation gems. 

Boron when it occurs in a glass is present either as boric acid 
or else combined with the bases as borates. It lowers the melting 
point of a glass and also causes it to become more fluid at any par- 
ticular temperature than the corresponding silicate glass without 
the boron. This allows the gases to escape more readily during 
clarification. Boron lowers the coefficient of expansion and imparts 
toughness to the glass. It also gives the glass special optical prop- 
erties and is used on this account in the manufacture of various 
kinds of optical glasses. It is also used for assisting the develop- 
ment of certain colors in glass. It has one disadvantage in that 
it causes the glass to become more susceptible to attack by acids, 

Boron is usually added to the glass batch in the form of borax, 
(Na2B4O7.10H2O). During fusion the water passes off leaving only 
the NagB^Oy to enter into the composition of the glass. Borax oc- 
curs as a mineral in nature, but most of the borax of commerce is 
manufactured artificially from the mineral colemanite (CaoBoOu- 
5H2O). In the United States the principal deposits occur in south- 
em California. Here borates are abundant in the dried up marshes 
of the desert region. Colemanite occurs over considerable areas in- 
terstratified with clays and sandstones, deposited in former lake 
basins whose waters have long ago evaporated. One of the most 
noted localities is Death Valley in Inyo County. 

Phosphoric Acid and Arsenloue Acid. 

Phosphoric acid and arsenious acid are sometimes added to glass, 
the former in the shape of bone ash, which is a calcium phosphate 
and the latter as arsenious oxide, AsaOg. As acid radicals, however, 


they play a very unimportant role. Phosphoric acid is occasionally 
used in the production of certain special glasses, such as Jena phos- 
phate crown, which contains 60% F^O^, The more common use for 
phosphoric acid in glass, however, is an opacifier, and of arsenious 
acid as a clarifier. These substances are, therefore, again "briefly 
referred to under those heads. 



An alkali base, either sodium pr potassium, is present in' prac- 
tically every commercial glass. In the case of bottle, window, plate 
and lime flint glasses the alkali employed is sodium, while in the 
case of lead flint it is potassium. 

Sodium Oxide. . NasO. 

Sodium is introduced into the glass batch either as sodium car- 
bonate, called soda ash, or as sodium sulphate, called salt cake by 
glass men. Sodium in small quantities is also introduced occasion- 
ally as sodium chloride or sodium nitrate, but not with the object 
of supplying alkali. These salts assist in various ways, which are 
taken up later in the chemical reactions which take place when the 
batch is fused. The mineral cryolite (AlNagFe), which is occa- 
sionally used as an opacifier, also contains sodium, as does borax, 
which has already been referred to. 

Sodium carbonate is manufactured from sodium chloride (common 
salt or rock salt) either by the **black ash" or "Le Blanc" process, or 
by the "ammonia soda" or "Solvay process." The latter process 
is the more economical of the two, the product is purer, and there 
are no troublesome by-products, such as tank waste. Therefore it , 
has gradually replaced the "Le Blanc" process. 

In the Le Blanc process the sodium chloride is first converted into 
the sulphate by treatment with sulphuric acid. The reaction takes 
place in two stages as follows: — 

NaCr + H^SO^ =NaHSO, + HCl 
NaCl + NaHSO^ = Na.SO, + HCl 

The sulphuric acid should have a strength of between 57°and 60° 
Baume. The first action takes place at a comparatively low tem- 
perature at the back of the furnace. When it slackens the charge 
is raked forward and is exposed to a higher heat, thereby causing 
the second reaction to take place. When the carbonate is to be 
used for the glass industry, lead pans are usually employed in the 
furnace. The sodium sulphate produced in the above manner is then 


mixed with limestone and powdered coal in about the following pro- 
portions: — 

Sodium sulphate 100 parts. 

Calcium carbonate, - 100 parts. 

Carbon, - 50 parts. 

This mixture is introduced into the back end of a long reverbera- 
tory furnace heated to a rather low temperature at first and is then 
raked forward nearer the grate, where the tempeature is much higher, 
reaching 1000° C. The mass is constantly stirred. After a while it 
stiffens and a blue fiame appears, indicating that the reaction is 
complete. It is now worked into a ball and raked into wagons 
where it rapidly solidifies. Revolving furnaces are replacing the 
hand worked reverberatory furnaces. 

The black ash from the furnace is of a very dark brown or gray 
color, with porous fracture. It contains about 45% sodium carbon- 
ate, 30% calcium sulphide, G% calcium carbonate, and small amounts 
of sodium silicate, sodium aluminate, sodium sulphide, sodium chlor- 
ide, ferric oxide, and coal. Usually very small quantities of cyanide, 
ferro cyanide and thiosulphate are also present. 

The material is placed in tanks with false bottoms and leached 
with water. The temperature is kept as low as possible, and air is 
excluded from the ash by keeping it covered with water to prevent 
secondary reactions from taking place in the ash, which would reduce 
the yield of carbonate. 

The principal impurities present in the solution obtained by the 
above leaching are caustic soda, sodium sulphide, sodium thiosul- 
phate, sodium ferrocyanide, sodium ferrosulphide, and traces of other 
compounds. It is allowed to stand for a time that material held in 
suspension may settle out. Then one of a number of methods of 
purification is employed. 

One way is to allow the solution to pass through carbonating 
towers, where it trickles over porous substances and comes into con- 
tact with a current of carbon dioxide and air. The caustic soda 
and sodium sulphide are here converted into carbonate, while any 
iron, silica and alumina present are precipitated. Another method 
is to add manganese dioxide, MnOj, to the solution, and pass super- 
heated steam and air through it. Sodium sulphide is oxidized to 
sulphate, and any iron, silica and alumina present are precipi- 

The purified solution is then evaporated in cast iron pans. As 
it becomes concentrated as crystalline powder, consisting of NajCOg- 
HjO, separates out. This on calcination to a red heat is converted 
into Na^COj. The mother liquor, which usually contains a large 
amount of caustic soda and sodium sulphide, is either further puri- 
fied, or else used for the production of caustic soda. 


In the ammonia soda or Solvay process a pure concentrated solu- 
tion of sodium chloride is saturated with ammonia. This is done 
in tanks with perforated false bottoms, through which' the ammonia, 
in the form of gas, is forced. The saturated solution is then run 
into a carbonating tower, consisting of a cast iron cylinder forty to 
sixty feet high and five to six feet in diameter, in which, at intervals 
of three to three and one-half feet, are fixed plates with a central 
openings. Over these plates are placed dome shaped diaphragms, 
which are perforated with numerous small holes. The ammonia 
brine is forced under pressure into the carbonating tower through 
a pipe which enters near the middle of the tower. The carbon diox- 
ide at a pressure of twenty-five to fifty pounds is forced into the 
lower end of the tower and allowed to bubble through the many 
perforated diaphragms. The following chemical reaction takes place 
in the tower: 

NaCl + NHg+HjO + CO, == NH^Cl + NaHCOj 

The bicarbonate of soda (NaHCOa) is insoluble in the ammonium 
chloride solution and precipitate out. It is drawn off, filtered, washed 
with cold water and calcined in cast iron pans. The carbon dioxide 
liberated during the calcining operation is pumped to the carbonat- 
ing tower and any ammonia given off is condensed and returned 
to the ammonia still. The gasses from the carbonating tower are 
likewise condensed to recover any ammonia which they contain. By 
treating the ammonium chloride formed with lime, the ammonia is 
regenerated. The carbon dioxide is derived from limestone, which 
also furnishes the lime for the regeneration of the ammonia from 
the ammonium chloride. 

The manufacture of sodium sulphate, or salt cake, from sodium 
chloride by treatment with sulphuric acid is carried on by the meth- 
ods outlined in the first step in the LaBlanc process. As shown two 
products are obtained, namely, sodium sulphate and hydrochloric 
acid. Salt Cake is, therefore, a by-product in the manufacture of 
hydrochloric acid. 

When salt cake, or sodium sulphate, is used as the source of sodium 
M is necessary to add a reducing agent to the batch, as silica alone 
cannot decompose sodium sulphate under the conditions existing 
in a glass furnace. A certain portion of^arbon, in the form of 
coke, charcoal or anthracite coal, must, therefore, be added to all 
glass mixtures containing salt cake, to enable the silica to decom- 
pose the sulphate. The reaction may be illustrated by the following 
equation : 

2Na2S04 + C + 2Si02 = 2(Na20.2Si02) + 280, + CO^ 

Coal to the extent of 4% to 7% of the weight of the sodium sul- 
phate, usually 6.5% to 7%, is necessary. 


There is still considerable difference of opinion in regard to the 
relative advantage of soda ash and salt cake as a source of sodinni. 
Salt cake is cheaper than soda ash, the difference in price, however, 
is no longer as great as formerly, when all the soda ash was manu- 
factured by the Le Blanc process. Salt cake has the disadvantage 
that it requires the addition of a reducing agent to the batch, which 
amount must be carefully regulated. 

Dralle favors the use of sodium carbonate. He claims a saving of 
30% in fuel by its use. The furnace may also be worked at a lower 
temperature, which causes it to have a longer life. The fining or 
clearing process proceeds more regularly and there is no formation 
of glass gall. 

American practice, on the other hand, seems to indicate that under 
certain conditions salt cake may be used to advantage. For ex- 
ample, Gelstharp and Parkinson^* found by experiments that in order 
to have no white scum or flake in a lime soda glass, where the ratio 
of soda to lime was less than 2:1, it was necessary to have sulphate 
of soda present. Frink^' found that glass made with salt cake, 
the furnace conditions being the same, is harder, has a higher soft- 
ening point, greater strength, and is less viscous at 845° C, than that 
made from soda ash, analyses showing that their composition is prac- 
tically the same. Also, the molten glass made from salt cake has 
the property of retaining any impressions made in or upon it in 
the form of a cord or wave to a much greater degree than does 
soda ash glass, and it requires temperatures in excess of 955** C to 
eliminate these defacts or to cause the chilled surface of the glass 
to again amalgamate with the main body. In the case of glass made 
from soda ash this takes place readily at a temperature of 900° C. 
Gelstharp in discussing the above paper states that plate glass made 
from ammonia soda ash, without any addition of salt cake, is more 
often reamy, and more diflOicult to free from fine seed than when 
salt cake is added, or when salt cake alone is used. He points out 
that the reaction between soda ash, limestone and sand takes place 
about 1040° C, and is finished at 1200° C, at which stage the mass 
is a mixture of silicates of soda and lime, with a large quantity 
of soda and ultimately a glass is produced full of fine gas bubbles 
and ream, due to the dissolving of the excess sand, the solution of 
which is very imperfectly mixed with the mass of the glass. To 
overcome this difficulty the glass must be raised to a higher temper- 
ature so that it will become very fluid. On account of the danger 
of the glass pots collapsing under these conditions, the heat is often 
shut off before the glass is perfect. On the other hand, when a cer- 
tain amount of salt cake is added to the soda ash batch, a new re- 

22. TransftctlonB Am<>rlcan Ceramic Society, Vol. IC. pp. 109-116. 

23. Transactloni American Ceramic Sodetj, Vol. 11, 1P09. pp. 290-810. 


action is caused to take place in the melt at a temperature of 
1310^ C. The sodium sulphate in the presence of carbon is decom- 
posed by the free sand, with the evolution of sulphur dioxide (SO,). 
This reaction becomes especially active at 1370° C. The fine seed 
from the first reaction is collected together by the new generation 
of gas, and the molten glass is thoroughly mixed by the violent 
evolution of gas, so that the reaminess caused by the dissolving of 
the free sand disappears. Qelstharp believes that the other differences 
in the properties of two similar glasses, made from soda ash and 
salt cake respectively, are due to the presence of small quantities of 
undecomposed sodium sulphate in the latter. 

Sodium chloride, or common salt, is sometimes added to the glass 
batch in small quantities. It melts at the low temperature of 800° 
C and thus assists in the fusion. As the temperature rises, however, 
it is largely lost by volatilization. In the presence of water vapor 
or steam it is decomposed by silica, with the formation of sodium 

2NaCl + HjO + SiO, = NaaO-SiO, + 2HC1 

Sodium chloride is of interest to the glass manufacturer because 
from it are produced the sodium sulphate and sodium carbonate 
which are the source of the sodium in glass. Salt occurs in nature 
in beds of varying thickness interstratified with sedimentary rocks. 
These deposits ^ere formed from bodies of salt water cut off from 
salt water lakes, which gradually evaporated under arid climatic 
conditions. At present the most important deposits from the stand- 
point of production occur in the states of Michigan, New York, Ohio, 
Kansas and Louisana. 

Potassium Oxide. KtO. 

Potassium is used in place of sodium in the manufacture of lead 
flint glass, which is a lead potassium glass, and in Bohemian glass, 
which is a lime potassium glass. Potassium gives a greater brill- 
iancy and smoothness to the glass than does sodium. On the other 
hand a sodium glass is said to melt clear more quickly and easily 
than potash glass. Potash is much more expensive than soda, and 
therefore it can only be employed in the better grades of glass, where 
low cost of production is not such an important factor as in the 
case of the more common varieties. 

Potassium is added to the glass batch in the form of the carbonate. 
Up to the outbreak of the present European war Germany has been 
the principal source of supply of potassium carbonate for this coun- 
try. Potassium salts, such as sylvite (KCl) and carnallite (KCl,- 
MgCl-GHjO) occur in vast beds at Stassfurt, Germany. From these 
salts the carbonate is manufactured in much the same way as sod- 
ium carbonate is prepared from sodium chloride. 


Nitre (KNO3) and orthoclase feldspar (KAlSiSOg), which are some- 
times added to the glass batch, also contain potassium, but these are 
added for other purposes than the supply of potassium to the glass. 

Lithium Oxide. Li.O. 

Lithium is occasionally used in the manufacture of fine optical 
glass. Its rarity and cost debar it from general use. 

Lime. OaO. 

Lime is an important constituent of most of the ordinary varie- 
ties of glass, including lime flint, plate, window, and bottle glass. 
It imparts smoothness and brilliancy to the glass and greatly in- 
creases its power of resistance to chemical agents. Glass with 
a high proportion of lime is hard and brittle and therefore more 
difficult to work, and must be annealed more carefully than one with 
less lime. > Increase in lime increases the fusibility of the glass up 
to a certain point, and tends to prevent the formation of cords, but 
it also increases the tendency to devitrify. Frink states that to in- 
crease the lime so that the glass contains more than 12.83% CaO 
tends to make the glass hard, brittle, and more difficult to fuse into 
a perfect glass. Tenacity and hardness increase up to 13.2% CaO, 
after which there is quite a rapid decrease in these properties. 

The source of the lime used in the glass industry is limestone, a 
rock occuring in nature in beds interstratifted with other sedimentary 
rocks. Calcium carbonate is present in solution in ocean waters, 
having been brought there by the streams whose waters dissolved 
it from the rocks through which they percolated. This calcium car- 
bonate is held in solution as HjCa (COa^j ^7 ^^^ carbon dioxide 
present in the water. There are a great variety of animals living 
in the sea that are constantly extracting this calcium carbonate for 
their own uses, by converting it into the normal insoluble CaCO, 
form. Out of it they build shells and skeletons to protect the soft 
parts of their bodies. Among them are such organisms as clams, 
oysters, corals, etc., down to forms not larger than a grain of sand, 
such as the foramenifera. When thes6 organisms die their skeletons 
drop to the ocean floor and accumulate there, forming deposits which 
often reach the thickness of several hundred feet. When other 
sediments are laid down on top of them these calcareous sediments, 
by pressure, become compressed and more or less recrystallized, form- 
ing the rock called limestone. But later diastropic movements of the 
earth's crust they may become elevated above sea level and exposed 
at the surface by erosion. Calcareous deposits are sometimes formed 
in a very much similar manner in fresh water lakes, but these are 
comparatively rare. 

When first deposited limestones consist of lime carbonate (CaCO,), 
but in time in certain places they sometimes become partially or 


completely converted into dolomite, CaMg (CO,) 2. This change 
probably largely takes place while the deposits are still beneath the 
sea, especially when the water is warm and shallow. 8ea water 
contains magnesium salts in solution. This change may, however, 
also be produced by waters containing magnesium in solution per- 
colating through the limestone, after it has been elevated above sea 

Limestone, therefore, is composed of calcium carbonate of varying 
degrees of purity, the more common impurities being magnesia, silica, 
clay, iron, oxide, and bituminous or organic matter. These impuri- 
ties may have been deposited with the calcareous matter in suffi- 
cient quantities to give character to the rock. The terms dolomitic, 
siliceous, argillaceous, ferruginous, or bituminous are, therefore, often 
applied to limestones to describe them. The color of limestones 
varies with the amount and nature of the impurities present. When 
pure the rock is light in color, but various shades of gray to black 
are the more common colors on account of the impurities. 

The limestones likewise show great variations in chemical composi- 
tion. Magnesium carbonate may be present from traces up to the 
percentage amount required for dolomite (CaMgCCOj),). Silica may 
range from a trace up to the point where the rock becomes a calcar- 
eous sandstone. Similar gradations of limestone into calcareous 
shales occur, according to the amount of clayey material present. 

In quarrying a particular bed of limestone variations in chemical 
composition may be encountered both laterally along the bed and 
vertically across its thickness. A particular stratum does not neces- 
sarily remain of uniform composition over any very extensive area. 
When the composition of the limestone is an important factor, 
therefore, as in the case of the glass industry, chemical analyses 
should be made from time to time. , . 

For glass making purposes the limestone should be as pure as 
possible. Small quantities of silica and alummina are not necessar- 
ily detrimental. The iron content, however, must be low when a 
white glass is being made, but since a smaller quantity of limestone 
is used for a given weight of glass produced than the quantity of 
sand used for the same purpose, the presence of a somewhat higher 
percentage of iron is permissable in the limestone than in the sand. 
For the better grades of glass, however, Rosenhain states that the 
iron jhould not exceed 0.3%. 

There is still some difference of opinion in regard to the amount 
of magnesia permissable in the limestone for glass making. The ten- 
dency is to allow a somewhat higher percentage than formerly. 
Frink" states that it may be present in amounts up to 6% in the 

24. Trannactloni American Ceramic Society, rol. 11, 1900, pp. 296-Sll. 


lima Usually a high calcium lime^ that is one containing only 0.0 
to 5.0% magnesia is demanded by the glass manufacturers. 

Magnesia makes the glass less soluble and lowers its coefficient 
of expansion. It also decreases the tendency of the glass to devitrify. 
On the other hand it tends to make the glass less fusible and in- 
creases its viscosity. There is not likely to be any trouble from this 
source, however, unless the magnesia content is extremely high. 
It also increases the hardness of the glass and makes it more diffi- 
cult to plain. 

Limestones sometimes contain flint concretions, which have al- 
ready been described under silica. If they remain in the crushed 
stone in the form of fragments they prove very refractory, and are 
apt to remain as opaque enclosures or stones in the finished glass. 
Amorphous calcium phosphate in connection with fossil remains 
and silicates of lime, magnesia and alumina are also present at times 
in limestones. They also tend to form small white stones in the 
glass. The same care, must, therefore be taken in selecting a suit- 
able limestone for glass making purposes as is observed in the case 
of the sand. 

Lime may be added to the glass batch in any one of three different 
ways: either as crushed limestone (CaCOg), as burnt or quick lime 
CaO, or as slaked lime (Ca(0H)2). The burnt lime is made from 
limestone by heating the latter to a temperature of about 900° C in 
a kiln. At this temperature the carbon dioxide is driven off, as 
shown by the following equation: 

CaCOg +heat=CaO + COj ' 

To produce slaked lime water is added to the burnt lime, which 
causes the following reaction to take place, with the evolution of 
considerable quantities of heat: 

CaO-fH20 = Ca(OH)2 

The tendency at the present time is more and more to use the 
ordinary crushed limestone instead of either the burnt lime or the 
slaked lime. With modern improvements in crushing machinery it 
is a comparatively easy matter to crush the limestone to the desired 
fineness. This was. not the case in the early days of the glass in- 
dustry, when the use of burnt lime and slaked lime was started. 

When burnt lime is used there is a saving of heat in the furnace, 
because the carbon dioxide has already been removed, an operation 
which requires considerable heat. On the other hand the liberation 
of the carbon dioxide from the carbonate helps stir the glass during 
the melting process. One great disadvantage in the use of burnt 
lime or slaked lime is that the former absorbs both moisture and 
carbon dioxide from the atmosphere, while the latter absorbs carbon 
dioxide. This naturally causes the composition to vary, the amount 


depending upon the conditions under which the lime is stored and 
the length of time. Such variations in composition naturally intro- 
duce errors into the calculated composition of the batch, unless the 
lime is analyzed each time before using. This is rarely done. 
Crushed limestone on the other hand, no matter how long it is 
stored, retains a constant composition. 

Lime is sometimes introduced into the glass in the form of fluorite, 
a calcium flouride, or as bone ash, which consists of calcium phos- 
phate. These substances are not added on account of their lime 
content, however, but are occasionally used to produce translucent, 
opal, and opaque white glasses. 

Magnesia. MgO. 

Magnesia is only introduced intentionally in notable quantities 
in special glasses, where the properties it confers are of special 
value. In the case of ordinary glass it often enters into its com- 
position in small quantities on account of its presence in the lime- 
stone used. 

Magnesia occurs in nature as the mineral magnesite, MgCOg. This 
is sometimes used, but often where extreme purity is desired the 
artificially precipitated carbonate or else calcined magnesia is pre- 

Barium Oxide. BaO. 

Barium oxide is sometimes used in the manufacture of glass. Com- 
pared with lime, barium compounds increase the density or speci- 
fic gravity of the glass and gives it a higher index of refraction, 
so that a barium glass has a gi^ater brilliancy than a lime glass, 
causing it to closely resemble a lead glass in this respect although 
not quite equal to it. There is also a considerable increase in the 
elasticity, tenacity and modulus of rupture, and a lowering of the 
specific heat in the c^e of barium glasses as compared with the 
lime ones. This makes barium glass very desirable for many usejs, 
such as table ware, lamp chimneys, globes, etc. In hardness and 
coefficient of expansion barium glasses are practically identical with 
lead glasses. Barium has the advantage over lead that its silicates 
remain unaffected by the products of combustion, whether reducing 
or oxidizing, of the glass furnace, so that barium glasses can be 
melted in open pots or in tanks. 

Barium is sometimes added, both in the case of lime alaki and lead 
alkali glasses. There is still considerable difference of opinion wether 
the barium should be used to replace the alkali or the lime, or 
whether it should partially substitute both. Satisfactory glasses 
have been made according to all three of these views. When bariupi 
carbonate is used to replace calcium carbonate, 1.97 parts of the 
former must be employed to replace one part of the latter. In 
case barium sulphate is used 2.34 parts must be employed for each 


part of calcium carbonate. In this case, as in the case of salt 
cake, a reducing agent must be added, usually some foim of carbon. 
Theoretically 2.7% of carbon are needed, but in practice it is found 
that 4% to 7% must be added. When barium carbonate is substi- 
tuted molecularly for lead oxide (PbO), 0.88 parts of the former must 
be used to replace one part of the latter. In the case of a lead glass, 
barium sulphate cannot be used, as it is impossible to add carbon to 
a lead glass batch on account of the danger of reducing some of the 
lead and thus blackening the glass. 

Some of the disadvantages of using^ barium are, as pointed out by 
Prink^^, that when a barium glass is melted in a pot or tank it has 
a disagreeable and unsatisfactory way of separating, stratifying, and 
laminating, so that when a lump is gathered and this is work^ in 
any manner, it is quite likely to show a cordy condition. Also, if 
the barium exists in about the right percentage it causes the glass to 
devitrify very easily and rapidly. A fine brilliant polish, with 
hydrofluoric acid, like that obtafned with lead glass cannot be pro- 
duced in the case of barium glass. 

Barium occurs in nature both as the carbonate, in the form of the 
mineral witherite, and as the sulphate, in the form of the mineral 
barite. The latter is more abundant than the former. It cannot be 
employed in connection with lead glasses for reasons already men- 

On account of its high cost as compared with lime, barium cannot 
be used in the manufacture of the cheaper grades of glass. It finds 
it chief application in the production of certain types of rolled glass, 
holloware, crystal, and table glass, and in special glasses such as Jena 
phosphate crown, which contains among other things 28% BaO and 
60% P^O,. 

Strontium Oxide. SrO. 

Strontium is seldom used in the manufacture of glass as it imparts 
no special properties to the glass. It occurs in nature as the car- 
bonate in the fonn of strontianite, and as the sulphate in the form 
of celestite. 

Zinc Oxide. ZnO. 

Zinc oxide is used occasionally in the manufacture of glass, but 
usually only in the case of certain special glasses, as optical and heat 
resisting glasses. A glass containing zinc has an index of refraction 
only a little higher than that of an ordinary lime glass. Zinc 
glasses have a high tenacity and compressive strength, are very re- 
sistant to chemical decomposition, and have a high fluidity and low 

25. Transactions American Ceramic Society, toI. 12, 1010, pp. .370-875. 


coefficient of expansion. One serious disadvantage is that a high 
zinc glass tends to devitrify readily. When zinc is added in large 
amounts to a glaiss batch it remains in suspension in the glass, or 
separates out on cooling/ causing the glass to become opaque. 

Zinc is added to the glass batch in the form of the white oxide of 
zinc, prepared artificially by the oxidation of the metal itself or of 
carbonate ores. This is a very volatile substance and care must be 
taken in its use or volatilization losses will be high. 

Lead Oxide. PbO. 

Lead oxide is an important constituent of lead flint glasses used 
extensively in the manufacture of cut glass ware and many optical 
glasses. Lead increases the specific gravity, or density, of glass, 
and gives it a high refractive index. This accounts for the brilliance 
of lead flint glasses which makes them so desirable for the manu- 
facture of fancy cut glass ware. They are also softer than ordinary 
lime glasses and can, therefore, be exit and polished much more read- 
ily. Lead glasses are resistant to chemical action and do not devitrify 
readily. They are also more easily fusible and more plastic than 
lime glass. 

Lead is added to the glass batch either as minium or red lead 
(Pb304), or as litharge (PbO). Litharge is produced on a com- 
mercial scale by oxidizing metallic lead. This is accomplished in 
cupellation furnaces, by heating the molten lead under oxidizing con- 
ditions in oval or rectangular shaped pan like hearths, placed on 
carriages which may be moved in and out of small reverberatory 
furnaces. The lead is thus converted into litharge (PbO) which 
when further heated at a temperature of about 300 °C, with the ready 
access of oxygen, is converted to red lead (PbgO^). If the tempera- 
ture is raised much above this, however, it will give off some of its 
oxygen and gain go back to litharge (PbO). 

Red lead is preferred to litharge by glass manufacturers because 
it liberates oxygen upon heating and, therefore, creates an oxydizing 
atmosphere in the glass pot. This is very desirable as reducing con- 
ditions are disastrous in a melt of lead glass on account of the tend- 
ency of the lead oxide to become reduced to the metallic state, and 
thus blacken the glass. It is for this reason that lead glasses must 
always be made in closed pots, where all reducing furnace gasses can 
be kept from the molten glass. 

Red lead for use in the manufacture of glass must be free. from 
metallic lead and discoloring metallic impurities, such as copper and 
iron. The percentage composition of lead in red lead is apt to vary 
so much that chemical analyses are necessary from time to time to 
keep the composition of the glass batch constant. 


Alumina. AUOs. 

The effect of alumina on glass has already been discussed under 
the heading of alumina as an impurity in glass sands. Due to its 
extremely slight solubility it increases the chemical resistance of 
the glass and also gives it valuable physical propertiea Large 
quantities cannot be added on account of its high melting point. 
On account of the lowering of this by the presence of other oxides, 
however, it is often added up to 10%, according to Dralle. 

In the case of alkali free glasses it is added in the form of the 
mineral kaolin (H^AlgSijOg), in other cases as feldspar, usually 
orthoclase (KAlSijOs). Orthoclase in conjunction with fluorine 
preparations is used as an opacifier. Alumina also enters into the 
composition of the glass when the mineral cryolite (AlNagFo) is used 
as an opacifier. 

J Thallium. 

Thallium is a rare metal which is occasionally used in the manu- 
facture of optical glass of high refractive power. It is found in 
nature in certain specimens of pyrite and in some mineral waters. 
The metal is generally extracted from the flue dust of furnaces iir 
which pyrite containing the element is burned. The dust is treated 
with dilute sulphuric acid and the thallium precipitated in a crystal- 
line form by means of zinc. 

Igneous Rocks and Slag. 

Ingeous rocks consist chiefly of silicia, alumina, ferrous and ferric 
oxides, magnesia, lime, soda, and potash. The relative percentages 
of these oxides shows a considerable variation in different types of 
igneous rocks. Those that have a high silica content are called 
acid or silicious, while those which have a relatively high iron, 
magnesia and lime content, are called basic. From an inspection 
of the above constituents it is seen that these are the oxides which 
are present in glass and that, therefore, igneous roc^s, except inso- 
far as the iron content may interfere, can be used as raw material 
in the manufacture of glass. In the case of green or brown bottle 
glass the iron content would not necessarily be detrimental. The 
siliceous rocks which as a general rule also have the highest alkali 
content are the most desirable, because alkalies are more expensive 
than lime. 

Igneous rocks have been used to a slight extent in Europe as a 
raw material by crushing and adding to them the necessary constitu- 
ents,: so that the composition of the batch yields a workable glass. 
At tjhe best, however, only the cheapest grades of glass, such as bottle 
glasfj, may be made from these materials. 

Iii a similar manner blast furnace slags, from the manufacture of 
pig/iron, have been employed as raw materials in the manufacture of 
th^ cheaper grades of glass. One of the greatest difficulties in th 



manufacture of glass from either igneous rocks or slag is to keep the 
batch uniform in composition. These materials vary greatly in com- 
position so that numerous chemical analyses are necessary to obtain 
a glass of approximately uniform composition, day after day. 


In the melting of the glass batch, when the last trace of unde- 
composed raw material has disappeared, the resulting glass is found 
to have thickly disseminated through it small bubbles of gas derived 
from the decomposed carbonates, sulphates, etc. In order to free 
the glass from these bubbles it must be heated further and more in- 
tensely. This causes it to become more fluid and, therefore, allows 
the gas bubbles to escape more readily. This process is known as 
'^fining." It takes place much more readily if the bubbles are large, 
and in fact it is almost impossible to get rid of very minute bubbles 
in this way. An attempt is therefore made to prepare a batch of 
such composition that it will yield only large bubbles. Sometimes 
where this is not possible some substance is added which rapidly 
evolves a great many large bubbles of gas. These in their upward 
course sweep the small bubbles ayay with them. Substances used 
in this manner are called ^^clarifiers." 


Arsenic Tri oxide. AstOs. 

Arsenic trioxide vaporizes without melting. It has several effects 
on glass in fining, the most important of which is a mechanical one. 
It has a higher specific gravity than molten glass, the former being 
about 3.7, while that of the latter is only about 2.6. Therefore when 
a piece of arsenic trioxide is thrown on top of the molten glass, it 
sinks into the melt on account of its high specific gravity, and vapor- 
izes very rapidly. The rising bubbles stir up the glass, sweep up the 
smaller bubbles in it, and tend to cause it to become homogeneous. 

Dralle thinki^ that at the same time it may have a chemical influ- 
ence. It may act as an oxidizing agent, by becoming reduced to 
arsenic. It can then form arsenic trisulphide with sulphur. Both 
arsenic and arsenic trisulphide are volatile, and a purification from 
coloring matter due to sulphur thus results. On account of the high 
volatility of arsenic trioxide it is only rarely that any arsenic remains 
in the glass. 

A further use of arsenic is to remove over coloring when an excess 
of selenium or manganese has been added in decolorizing, and the 
glass has a slight pink color. By the careful addition of arsienic 
this may be removed. In the case of selenium an oxidation of! the 
selenium results. In the case of the manganese dioxide the reaction 
is not so well understood. The colors obtained with the other me- 
tallic oxides may also be clarified by "fining" with arsenic. 



Soda Nitre, or Ohili Saltpetre. NaNO«. 

Soda nitre melts at 318°C. At a little above its melting point it 
breaks up into sodium nitrate as follows: 


At a still higher temperature Ihe nitrite is decomposed still further 
as follows: 

2NaN0,= Na,0+N,0+02 

Only the sodium oxide enters into the composition of the glass. The 
other constituents pass off as gases. Sodium nitrate is found in 
large deposits in northern Chili. 

Nitre, or Saltpetre. KNO.. 

Nitre is prepared artificially from sodium nitrate and potassium 
chloride according to the following reation : 


It melts at 340°C and breaks up into the nitrite at 500°C, while at 
very high temperatures it is further decomposed, thus behaving like 
the sodium nitrate. 


Only the i>otassium oxide enters into the composition of the glass. 

The importance of both nitrates rests on the evolution of oxidizing 
gasses, which burn off organic compounds and the yellow coloring 
sulphur. They also facilitate fusion because they melt at compara- 
tively low temperatures and then dissolve the more difficultly fusible 
constituents of the batch. The evolution of the gas also tends to 
stir the melt. They are not as valuable as arsenic in this respect be- 
cause the decomposition has been largely completed before fining 
.sets in. 

The usefulness of salpetre lies in the fact that the bad effect of car- 
bonaceous materials or reducing flames may be counteracted by its 
use. It cannot be employed, therefore, where the glass must be 
melted under reducing conditions, as in the case of copper red glasses, 
or where carbon is added to sulphate batches. The solvent power 
of the molten and decomposing saltpetre on the pots is bad. Its 
high price is also against its more common use. On account of the 
fact that sodium nitrate absorbs water, potassium nitrate is more 

Vesetable Substances. 

Frequently some vegetable substance containing much moisture 
is introduced into the glass to produce the desired evolution of gas. 
One method is to place a potato in the crook of a forked iron rod 


and then to dip the rod with the attached potato into the molten 


It has already been shown that it is practically impossible to en- 
tirely keep iron out of the glass batch, inasmuch as there are usually 
minute amounts of this substance present in the glass sand, lime- 
stone, soda and other materials employed. Of courae the purest 
varieties of glass contain only the merest traces of this element. 
Cheaper grades, however, always contain iron in measureable quanti- 

Iron may exist in the glass either in the ferrous or the ferric con- 
dition. If the glass is produced under reducing conditions, which 
is usually the casern a glass making furnace, the iron is present in 
the glass in^faSra^ras state. It then shows a decided greenish-blue 
tint, wh(»i^ depth depends upon the amount of iron present, pro- 
vided/fu) "decolorizer" has been added. If an oxidizing agent is 
add^ to the molten glass the iron is brought into t^e^fCTric^ondition. 

then colors the glass a characteristic yellow tint, which is much 
less intense and vivid than the corresponding green color of the same 
amount of ferrous iron. To overcome these color effects of iron and 
produce a glass which appears colorless to the eye, certain decolor- 
izing agents are sometimes added to the glass batch. 

Manganese Dioxide. BinOt. 

Manganese is one of the important decolorizers employed by the 
glass manufacturer. It is usually added to the glass batch in the 
form of the black manganese dioxide (MnOj), which occurs in nature 
as the mineral pyrolusite in a form sufficiently pure to be employed 
for this purpose. Analyses should be made from time to time, how- 
ever, to see that the pyrolusite used is free from iron, as oxides of 
iron sometimes occur as impurities intimately mixed with the pyro- 
lusite. Such occurrances of the mineral cannot be used for decolor- 
izing purposes. 

When manganese is introduced into glass in the absence of other 
coloring ingredients a pinkish purple to violet color is produced, 
according to the chemical nature of the glass. The exact color pro- 
duced depends not only upon the chemical^ composition of the 
glass, but also on the heat and duration of the "fining" process, and 
the reducing or oxidizing conditions of the furnace. Its employ- 
ment, therefore, requires much skill and care in order to get the de- 
sired results. 

If some iron is present in the glass batch, and a little manganese 
dioxide is added, instead of obtaining a colored glass, the two tints 
due to iron and manganese appear to neutralize one another and 
a glass which is apparently colorless, as far as the eye is concerned, 


is obtained. Two theories have been advanced to explain this decol- 
orizing effect of manganese dioxide. One is that the pink color pro- 
duced by the manganese is approximately complimentary to the green- 
ish blue of the ferrous iron and that the glass, therefore, transmits 
light of approximately neutral color. The other is that the man- 
ganese dioxide acts as anjUKl'winj^ iigenl, OXldlalllg the ffFwiifi, to 
ferric ironT The laiteras already stated gives the glass a very lif i ;ht 
ye llow ti flge,.^a(Ltiiai ii beco mes practica lly colorless. There seems 
to be a little moreeviaence in favor oi the iirsi th^fy than the sec- 
ond (Transactions, American Ceramic Society vol. 13, 1911, pp. 251- 

The greenish blue tinge produced by iron can only be neutralized 
when vei7 small proportions, not over 0.1% of iron are present. 
When larger quantities are present the addition of manganese modi- 
fies the resulting color, but is no longer able to neutralize it. In this 
country about one ounce of manganese dioxide is added to one hun- 
dred pounds of sand, while in Europe fifteen to two hundred grams 
per one hundred kilograms are used. The best results are obtained 
with l ead flint, but it is also us e d tf ^ ^^rttiin e rti ii l In i h i i nut of 
r the lime-soda glassea One of the difficulties in the latter case is 
\ jha^ ^hen salt c^fep in ^iiripi/^y^i/^ ^q^i myt^t ^ added, which exerts a 
I reducing action on the manganese^and Interferes with its coloring 
I properties. Manganese cannot be added to the glass very readily 
I aft er the batch has been melted, as it sinks to the bottom and colors 
the mixture unevenly. The color also depends on the length of the 
melting process and the temperature attained. 

Olass containing manganese loses its pink color to a certain extent 
during annealing in a lehr, making it necessary to have the glass 
slightly pink before it goes into the lehr, for otherwise the glass 
would come out with a slightly greenish-blue tinge. On. the other 
hand glasses in which manganese has been used as a decolorizer on 
prolonged exposure to sunlight, or ultro-violet light, often assume a 
pink, purple or brown tinge. 

Nickel Oxide. NIC. 

Nickel oxide, which Is also occasionally used as a decolorizer, ex- 
erts a powerful coloring influence on glass^ The color produced de- 
pends on the chemical composition of the glass, and the state of oxi- 
dation of the nickel. It is usually of a greenish-brown tint. 

In sodium glass about five grams of nickel oxide per one hundred 
kilograms of sand are required to act as a decolorizer, while in po- 
tassium glasses the amount is still less. Nickel does not act as a 
decolorizer in the presence of lead, therefore its use is confined to 
the lime-alkali glasses. With nickel, as with manganese, only the 
effects of comparatively small quantities of iron can be neutralize<? 


Selenium. Se. 

Selenium can be used as a decolorizing agent for glasses of a cer- 
tain chemical composition. Under suitable conditions selenium pro- 
duced a yellowish pink coloration, the intensity of the color depend- 
ing upon the chemical nature of the glass and the amount of selenium 
left at the end of the melting process, this in turn depending upon 
the duration and temperature of the fusion. The pink color can be 
best developed in glasses containing barium as a base, but lime-potash 
glasses also give satisfactory results. It is not very successful in 
the case of lime soda glasses, and when added to a lead glass there 
is a tendency to develope the black selenide of lead, which prevents 
its use as a decolorizer in this type of glass. 

In the case of the lime potassium silicate glasses selenium gives 
very satisfactory results as a decolorizing agent to neutralize the 
color effects of small amounts of iron present in the glass. J One to 
one and one-half grams of selenium per one hundred kilograms of 
sand are usually employ3d, and the amount should never exceed five 
grams per one hundred kilograms of sand used. 


The different types of glass that have been referred to may be pro- 
duced in a large variety of different colors by the addition of a small 
quantity of one or more of certain chemical compounds, or elements, 
to the batch. The same material does not produce the same color 
in all glasses, this varying with the composition of the glass and 
also with the conditions under which the glass is produced. 

Colpirgd glasses may be divided into two classes: — namelyj_those 

in which_the^"color is introduced by a colored compound present in 
a state of solution in"the glass, and those in which the color is due 
to the optical effect of minute particles held in suspension by the 
glass. In the forme^case the intensity of t he col or is proportional 
to the concentration onEe"8bTution of the coloring material, while 
in the latter case the color depends upon the size and distribution 
of the particles. 

The coloring agents commonly employed to produce violet, blue, 
green, yellow, and red in glass are taken up in^the order named. 

Mnnganesc Dioxide. MnOa. 

Manganese has already been referred to under the head of decolor- 
izers. It produces a range of colors from amethyst to violet, ac- 
cording to the composition of the glass. The full color is only de- 
veloped when the manganese is in the completely oxidized condition, 
and it can be altered or discharged by introducing reducing sub- 
stances. In a lime-potash glass, manganese gives an amethyst color, 
while in the case of lime-soda or a^lead glass the color is reddish 


By adding manganese and iron together in considerable quantities, 
amber and brown glasses are produced. If the quantity is greater 
than the glass can dissolve the excess remains in suspension, pro- 
ducing black glass. 

Manganese is usually added to the glass batch as the black man- 
ganese dioxide, which occurs in nature as the mineral pyrolusite. 
For the finer grades of glass refined manganese dioxide or manganese 
carbonate are sometimes used. For bottle glass cheaper grades of 
manganese ores are employed, but their analyses must be watched. 

A little cobalt, in the form of the oxide, is sometimes added in con- 
nection with manganese to improve the violet color. 

Nickel Oxide.- NIO. 

Nickel oxide has already been referred to under decolorizers. It 
exerts a powerful coloring influence on glass, but the color varies 
considerably with the composition of the glass and the state of oxi- 
dation of the nickel. Its successful use therefore requires a great 
deal of skill. Nickel produces an amethyst color in a lime-potash 
glass, a reddish-brown color in a lime soda glass, and a purple color 
in a lead glass. A little cobalt oxid e is sometimes added with it 
to improve the violet color. 

Coft^t Oxide. yDoO. 

Cobalt is one of the most powerful coloring agents in glass, and is 
the oxide commonly used in producing all varieties of blue glass. 
The blue of cobalt is very little affected by the composition of the 
glass or by the state of oxidation of the metal. With lime-potash 
and lime-soda glasses it yields a violet blue color, while with lead 
glass it gives « spectrum blue. Only a very little is necessary, 0.1% 
being sufficient to produce a strong blue, while even as low as 0.01% 
yields a pale blue. Cobalt is usually added to glass in the form of 
the oxide, CoO. 

Copper Oxide. CuO. 

When copper oxide is added to a lime potash glass, under oxidizing 
conditionrL a pale blue color is produced in the glass by the formation 
of a cupric silicate, which is soluble in the glass. In the case of a ^ 
lime soda glass, under similar conditions, the color is a greenish- 
blue. ^^'^"^ ^^N 


F\N»a*»-exttre. FeO. 

The effect of ferrous iron as a coloring agent has already been dis- 
cussed under decolorizers. Ferrous iron colors a lime-potash glass 
a greenish-blue tint, a lime-soda glass a blueish-green, and a lead glaF 
a yellowish-green. The depth of the color depends upon the amoui 


of iron present. Attention has been called to the fact that iron is 
present as an impurity, at least in minute quantities, in practically 
all glass batches, and that ordinary varieties of glass, such as bottle, 
window, and plate, owe their blueish-green tint to the presence of 
small amounts of ferrous iron in the glass, occurring undoubtedly in 
the form of a silicate which is soluble in the glass. 

Copper Oxide. OuO. 

Copper oxide, under oxidizing conditions, produces a green color 
in lead glasses by the formation of a cupric silicate which is soluble 
in the glass. 

Ohromlum Oxide. CriOt. 

Chromium is a very active coloring substance and is therefore used 
extensively. Chromium colors glass various depths and shades of 
green^, the depth and shade depending upon t|ip proportion! of 
chromium used and the composition of the glasa In a lime-potash 
glass the resulting color is yellow-green, in a lime-soda glass a grass- 
green, and in a lead glass a reddish-green. 

Chromium has the advantage over many other coloring agents in 
that it is relatively cheap and can be readily obtained and introduced 
into the glass in the form of pure compounds, whose coloring effect 
can be accurately anticipated. It has the further advantage that 
colors produced by it are little affected either by reducing or oxi- 
dizing conditions in the furnace, and only slightly by the length or 
temperature of the melting process. The rate of cooling does, how- 
ever, have considerable influence on the color. 
♦ Chromium is only slightly soluble in glass and if added in amounts 
exceeding 4% or 5% the excess separates out on cooling producing 
an opaque, green glass. By careful manipulation it is possible to 
get the oxide to separate out in the form of crystalline flakes. The 
result is a translucent green glass filled with minute spangles, known 
as chomium aventurine. 

Chromium is added to the •glass batch either as the green oxide 
(CrgOa), as potassium dichromate (KaCrgO^), as potassium chroma te 
(K2Cr04), as a lead chromate (PbCrOJ, or as barium chromate 
(BaCr04). Of these potassium dichromate is the form most com- 
monly employed. Chromic oxide itself is an extremely refractory 
body, and is, therefore, comparatively difficult to incorporate into a 
glass. On the other hand if the chromium is added in the form 
of potassium dichromate its solution in the glass is very much facili- 

Uranium Oxide. UOi. 

Uranium produces a yellowish-green color in a lime-soda glass. 
While this is slightly fluorescent, it cannot compart in beauty with 


the yellow fluorescent color developed by Qranium in a lime-potash 
glass. Uranium may be added to the glass batch either as the oxide 
(UOg), which is a yellowish- hrnwij^ pnwHpr op as sodium uranate 
(NajUOy-SHgO), which ha>-a-^iitewish orang^olor. 


Ferric Oxide. Fe«0«. 

When iron is present in the ferric state it gives the glass a yellowish . 
tint which is not as marked, however, as the green color produced by 
an equal amount of ferrous iron. In the the case of a lime-potash 
glass ferric iron gives a yellowish-green tint, in a lime-soda glass a 
greenish-yellow, and in a lead glass a yellow-green. 


Sulphur produces a greenish-yellow coloration in alkali glasses by 
combining with the alkali and lime to form sulphides. Sulphur 
must be kept out of lead glasses, as the formation of lead sulphide 
throws lead out of solution and renders the glass opaque. 

Cterium Oxide. Ce0«. 

Cerium oxide produces a yellow color in glass. 

Uranium Oxide. UOs. 

Uranium produces a characteristic and beautiful yellow color in 
glass, which possesses a marked greenish fluorescence. This is 
especially true in the case of the lime-potash glasses. The fluor- 
escence is not so marked in the case of lime-soda glasses, and is ab- 
sent in the lead glass. Uranium may be added to the glass batch as 
the oxide (UO3), or as sodium uranate (NagUO^-SHjO). Sometimes 
it is added as uranyl-acetate (U02(C2H302)22) or uranyl-nitrate 
(UO^CNO,),). ? 

Silver. Ag. 

Silver under favorable conditions imparts an orange color to a lime- 
potash glass and a deep yellow to lime-soda and lead glasses. The 
color varies from light to dark according to the quantity used. By 
gradually increasing the amount a point is reached where opacity 
results. Repeated melting intensifies the color. The yellow color 
of silver is due to the colloidal suspension of fine particles of silver 
through the glass, which transmit yellow light. Silver may be in- 
troduced into the glass as the nitrate (AgNOg), as the chloride 
(AgCl), or as the borate (AggB^O^). When it is added in the form 
of silver chromate (AggCrO^) a beautiful greenish-yellow glass is 

Silver is usually applied to the surface of the glass as a stain. It 
is readily absorbed by the glass and this is taken advantage of to 


color sheet glass yellow by penetration. The glass is painted with 
one of the salts of silver and heated to about 400°C, causing it to 
absorb a certain amount of silver. When it is further heated to 
about 800°C the silver compound decomposes, and the silver goes into 
colloidal suspension producing a yellow color in the surface film of 
the glass. The temi)erature of combination and precipitation varies 
with the composition of the glass, lime-potash glass, low in silica, 
producing the richest colors. ^ 

OotiT>e*-O*4€ter''6u0 . 

When copper oxide is added to glass under reducing conditions, 
and the glass is cooled slowly, or is exposed to repeated heating fol- 
lowed by slow cooling, an intense ruby coloration is produced. The 
copper is precipitated in the glass in colloidal suspension. Carbon 
or some other organic reducing agent is usually employed, but in- 
organic substances, such as stannous chloride (SnClg), stannous 
oxide (SnO), or metallic tin, are also used. It is a matter of con- 
siderable skill to obtain the proper division and suspension of the 
copper to produce the ruby color. If the particles become too large 
and unevenly distributed, a streaky, opaque red results, resembling 
sealing wax. By exceedingly slow cooling and under other favorable 
conditions the particles of suspended cooling material grow in size 
and appear as minute shimmering flakes, producing what is known as 

The ruby color of copper is usually so intense that it can only be 
employed in very thin sheets by "flashing" it upon the surface of a 
colorless glass. This is accomplished by^ first taking a small gath- 
ering of ruby glass upon a pipe and then taking the remaining gath- 
erings required from a pot of colorless glass. When such a com- 
posite gathering is blown into a cylinder, the ruby glass lies as a 
thin layer over the inner surface of the cylinder. Care must be 
taken that this layer is evenly distributed and of the right thickness 
to produce just the tint of ruby required. The chemical compo- 
sition of the ruby glass and the colorless glass must also be such that 
the two glasses will have very nearly the same coefficient of thermal 
expansion, or internal strains will be set up in the glass which are 
apt to result in fracture. 

Gold. Au. 

Gold can be used for the production of brilliant ruby tints in the 
same manner as copper. Since gold has a greater tendency to return 
to the metallic state than copper, no reducing agents are necessary. 
The rate of cooling, however, must be carefully regulated. Rapidly 
cooled glass containing gold shows no special color, but when the 
glass is reheated and cooled slowly a rich, rose-ruby tint is developed. 


It is easier to obtain this color with gold than with copper as there is 
not the danger of oxidation to contend with. Lighter shades of red 
may also be obtained so that "Hashing" is not essential. 

The gold is added to the glass by mixing gold chloride (AuClg) 
with sand and scattering it over the surface of the batch. A mole- 
cular solution of gold in the glass is obtained. When this is re- 
heated and slowly cooled the gold particles become enlarged and a 
colloidal suspension of red gold in the glass results. 

Selenium. 8e. 

Selenium produces a pale, rose-red color in glass. The intensity of 
the color depends upon the chemical composition of the glass and the 
duration and temperature of the melting process. The pink color of 
selenium is best developed in those glasses which contain barium as 
a base. Lime-soda glasses do not show it as well. The use of 
selenium as a decolorizer has already been referred to. 


Under opacifiers are included those materials which when added 
to the glass both produce translucent, opal, alabaster or opaque white 
glasses. Opalesence is produced by bringing about a colloidal sus- 
pension of some suitable compound in the glass. If the particles 
are increased in size the glass becomes opaque. The following com- 
pounds are most frequently used for producing these types 6f glass. 

Calcium Phosphate. Oaa(P0«)a. 

Calcium phosphate when added to a glass batch in sufficient quant- 
ity produces a turbid white glass. In smaller amounts an opal 
glass is produced, which transmits a reddish light. The glass at 
first is colorless, the opalescent effect appearing only after the glass 
has been reheated. 

Fluorine Preparations. 

Certain fluorides when added to a glass bath produce opacity. 
Glass rendered opalescent by them does not transmit red light, as 
does an opalescent glass produced from bone ash (calcium phosphate) 
but is pure milk white. Alumin\im fluoride is usually employed. 
It is introduced into the glass batch either as a mixture of the min- 
erals fluorite (CaF^) and orthoclase (KAlSigOg), or as cryolite 

Tin Oxide. SnOj. 

Tin oxide in a fine suspended state, also produces opalescence in 
glass and in large quantities white opacity. 




The necessary mixture of raw materials, which when melted to- 
gether forms gla^, is known as the batch. One of the primary essen- 
tials of a good glass batch is that it be well proportioned and thor- 
oughly mixed. The exact composition varies considerably, even 
for the same kind of glass, depending upon a number of different 
factors, among which are the character of the raw materials em- 
ployed, the kind of fuel used, and the style and construction of the 
furnace. The success of the operation, therefore, depends largely 
upon the skill and intelligence w^th which the factors are studied 
and applied. A good batch for one furnace and a certain set of 
materials often proves unsatisfactory when used for another type of 
furnace, Or when the raw materials are procured from some other 
source. Recipes for glass batches which are derived from the prac- 
tice in one section do not always give successful results in some other 
locality, where working conditions are somewhat different. 

There is still considerable opportunity for improvement in con- 
nection with the preparation of glass batches. By keeping a better 
control of the chemical composition of the batch better results could 
be obtained in many cases. By making analyses from time to time 
of the raw materials going into the batch, the gaseous fuels em- 
ployed, and the glass itself, information can be acquired which if 
rightly understood and applied would undoubtedly lead to the more 
uniform obtaining of good results. The composition of the raw 
materials should be watched in particular. Variation in the com- 
position of any of these cannot but affect the resultant glass. 

Composition of the Batch. 

In the following tables the composition of several batches for each 
of the more common kinds of glass are given. They are calculated 
on the basis of 100 parts of sand. 

Window Glass Batches. 









LlTneatooe. -.- - 









Slaked Jlrae, i — - 



Soda ash. -_ 






Salt cake, 

Carbon. __- 







Window Glass Batches. Oontinued. 

Sand, — . 

Limestone. ^. 

Slaked lime, 

Soda ash. 

Salt cake, 

Oarbon, _. 





















Plate Glass Batches. 









Limestone, — 










Slaked lime. - 



Soda ash, 

8«)t cake, - * .. 







Oarbon, _ 



Manganese dioxide, 



Plate Glass Batches. Oontinued. 








Sand -.. 

Limestone, .... 









Lime, -_ _. 

Slaked lime, 




Soda ash, 








Salt cake, 


Arsenic, - — 

Maganese dioxide, 


Lime Flint Batches. 


Soda ash, 

Salt cake, J 


Chili saltpetre, 



Manganese dioxide. 



















Bottle Glass Batches, 



Soda ash, 

Salt cake, 

















Lead Flint Batches. 



Nitre — 

Red lead. 



Manganese dioxide, .. 

Lead Flint Batches, Continued. 








Sand, -^ 














Red lead, 



Manganese dioxide, . 






"" % 



Lead Flint Batches, Continued. 


Potash, — 


Red lead, 



Manganese, .. 















1. The Commoner and Olassworker, Vol. 21, No. 11, 1899. Quoting from EngMsh Pottery 

2. Die O'as-fabrlkatlon, 2nd edition, Raim and Gemer, Vienna, 1897 p 295 

8. Report on the Manufacture of Glarss. by Jos. D. W«eks, 1883. Census Rieport 

4. Glass. Robert Linton. The Mineral Industry for 1899, Vol. 8, pp 234-263 

6. Glass. Dictionary of Applied Chemistry, by Sir Edward Thorpe, Vol. 2, 1912 pp 719.7V 


At the time the batch consisting of the well mixed raw materials 
is charged into the furnace, some cullet or broken glass is also ad- 
mitted. This should preferably be crushed to the size of about one 
inch in diameter, but in practice in the case of the cheaper grades of 
glass this is seldom done. For the higher grades it becomes neces- 
sary to do so, or the glass lacks homogeneity, as lai^e pieces of cullet 
do not diffuse readily through the rest of the melt. In the case of 
such glasses it is also necessary to have the composition of the cullet 
similar to that of the glass produced, and the cullet should be clean. 

Cullet fuses at a much lower temperature than the raw batch, and, 
therefore,^ assists in the melting. Its presence also holds up and 
makes the mass more open, thereby allowing the ready escape of the 
gases during the early stages of the fusion. An excess of cullet, 
however, produces a brittle or weak glass. Just how much may be 
added without injury to the glass is still a disputed question. Some 
recommend the addition of a weight of cullet equal to the weight of 
the sand used, while others think that as low as one-third that 
amount is nearer the right figure. 

Methods of Calculating Glass Batches. 

To calculate the composition of the glass from that of the batch. 


Sand - - - 100 pounds 

Limestone. - - 35 pounds 

Soda Ash 32 pounds 

Salt Cake 6 pounds 

Coal - - 0.4 pounds 

Analysis of Sand. Analysis of Limestone. 

SiO,. 99.7 % SiO, .92 % 

AhO. 24 % Al,Os 1.00 % 

Fe.Ot. .„ 026% Pe^Os .10 % 

CaOO, 95.20 % 

99.966% MgCOa - 2.40 % 

99.62 % 

Analysis of Soda Ash. Analysis of Salt Cake. 
Na,CO« 98.00 % Na«SO«, 97.00 % 

Assume, a volatization loss of 5% of the sodium in the furnace. 
This is a somewhat higher figure than usually occurs in practice. 

Molecular weight of NaiO 62.1 

CO, 44. 

Na.CO. 106.1 

Molecular weight of NaaO 62.1 

SO3 _ 80.06 

Na.SO* 142.16 

Molecular weight of CaO, 56. 

COa. 44. 

CaCOa 100. 

Molecular weight of MgO, 40.36 

CO. 44.00 

MgCO., 84.36 


100 X .997 = 99.7 pounds SlOt in the sand. 
100 X .0024 = 0.24 pounds AlsOa in the sand. 
100 X .00026= 0.026 pounds FesOa in the sand. 


35 X .952 X = 18.659 pounds CaO in the Limestone. 


35 X .024 X = 0.402 pounds of MgO In the limestone. 

35 X .0092 = 0.322 pounds of SiO* in the limestone. 
35 X .01 = 0.35 pounds of AlaOa in the limestone. 
35 X .001 = 0.035 pounds of FeaOa in the limestone. 


32 X .98 X = 18.35 pounds Na«0 in the Soda Ash. . 



6 X .97 X = 2.54 pounds of Na.O in the Salt Cake. 


18.35 + 2.54 = 20.89 pounds of NasO. 

20.89 — 5% (volatization loss) = 19.85 popnds of NaaO for the glass. 

99.7 pounds SiOs in sand. 0.24 pounds AlaOa in the sand. 

.322 pounds SiOa in limestone. 0.35 pounds AlaOa* in the limestone. 

100.022 pounds of SiOa for the glass. 0.59 pounds of AlsOa for the glass. 

0.026 pounds FeaOa in sand. 
0.035 pounds FeaOa in limestone. 

0.061 pounds FeaOa for the glass. 

100.022 pounds SiOa Oalculating on the basis of 100%. 

.59 pounds AlaOa SiOa 71.6 

.061 pounds FeaOa AlaOa - .4 

.402 pounds MgO FeaOa. — .06 

18.659 pounds CaO MgO 8 

19.85 pounds NaaO OaO 18.4 

NaaO 14.2 

139.584 pounds. 


To Calculate the composition of the Batch from that of the Glass. 

Analysis of the Glass. 

SiOa 72.68 

AljOa, FetO, 1.06 

MgO, ._ 26 

CaO 12.76 

Na,0 13.24 


The same sand, limestone, and salt cake as in the previous calcu- 
lation are to be used. No soda ash is to be employed in this case. A 
volatization loss in the furnace of 5% for sodium is assumed. 

start with 100 pounds of glass. 

100 X .1276 = 12.76 pounds of CaO in the glass. 

100 100 

12.76 X X = 23.93 pounds of limestone required to furnish the OaO. 

56 95.2 
100 X .7268 = 72.68 pounds of SiOa in the glass. 
23.93 X .0092 = 0.22 pounds of SiO« in the limestone. 
72.68 — 0.22 = 72.46 pounds of SiOa to come from the sand. 

7''. 46 X = 72.68 pounds of sand required. 

99 7 
100 X .1324 = 13.24 pounds of NaaO in the glass. 


13.24 X = 13.94 pounds of NaaO after volatization loss is added. 



142.16 100 

13.94 X X = 32.9 pounds of NasSO« (Salt Cake). 

62.1 97 

23.93 X .01 = 0.24 pounds of AlsOs In the limestone. 
72.68 X .0024 = 0.17 pounds of AUOa in the sand. 

0.41 pounds of AltO» in glass resulting from this batch. 
23.93 X .001 = 0.02 pounds of Fe,Os in limestone. 
72.68 X .00026 = 0.02 pounds of FeaO» in sand. 

0.04 pounds of FeaO» in 100 pounds of glass resulting from 

this batch. 

0.41 + 0.04 = 0.45 pounds of AltO« and FesO». This amount is 0.61% less than 

that of the glass for which the batch is being calculated. The difference is 

due to using a sand and limestone of slightly different composition Irom 

that used in the original glass. 


23.93 X .024 X = 0.27 pounds of MgO in 100 poimds of glass resulting 

from this batch. This is the same as that of the glass for which the batch is 
being calculated. 

Resulting Batch. Calculating on the basis of 100 pounds 

72.68 pounds of sand. of sand. 

23.91 pounds of limestone. Sand, 100 pounds 

32.90 pounds of Salt Oake. Limestone. 33 pounds 

45.4 X .065 = 2.95 pounds coal. Salt Cake, 45.4 pounds 

Coal. 8 pounds 

To Calculate the Composition of the Batch from the Molecular Relationship 

of the Lime. Soda and Silica. 

Tscheusehner has derived the following formula for a normal glass: 


xRSO . yR^O . 3 (— + y) S10«. 

xR^t represents the sum of the molecular ratios of the NaiO and KiO. 
yR" represents the sum of the molecular ratios of the CaO, MgO, BaO, PbO. 
ZnO and FeiOs. 

For a lime soda glass, according to Dralle, when y is made equal to 1. x 
can vary between .5 and 1.0. 
Assume therefore a case where x = 0.9 and y = 1. 
Then 3 (— + y) = 5.4. 


Tlie same sand, limestone and salt cake as in the previous calculation are 
Ko be used. A 5% loss of sodium in the furnace is assumed. 
The limestone contains 95.20% CaCOa and 2.40% MgCOa. 


2.40 MgCOa are equivalent to 2.4 x = 2.84% CaCOa. 

95.20 + 2.84 = 98.M% limestone. 

To get 1 molecule of CaO requires 1 molecule of CaCos. 
1 pound molecule of CaCOs weighs 100 pounds. 

100 X = 102 pounds of limestone. 

102 X .0092 = 0.94 pounds of SiOs in limestone. 
Molecular weight of SiOs is 60.4. 
5.4 molecules of SiO« are required. 
5.4 X 60.4 = 326.16 pounds of SiOt. 

326.16 — 0.94 = 325.22 pounds of SiOs to be derived from the sand. 

325.22 X = 326.2 pounds of sand. 

0.9 molecules of Na«0 are required. 
This will require 0.9 molecules of NagSOi. 
NasSOi = 97% pure and there is a 5% volatilization loss. 
100 100 

0.9 X X X 142.16 = 138.8 pounds of salt cake. 

95 97 

Batch. Calculating on the basis of 100 pounds 

Sand. 326.2 pounds of sand. 

Limestone. 102.0 pounds Sand 100 pounds 

Salt Cake, 138.8 pounds Limestone. 31.3 pounds 

42.6 X .065 = 2.769 pounds of coal. Salt Cake. 42.6 pounds 

Coal. -. 2.75 pounds 


The alumina and ferric oxides were neglected in the above calcu- 
lation, as they are present in only small amounts. 

Mixing the Batch. 

It is absolutely essential that the batch be thoroughly mixed before 
it is charged into the furnace. A special room which can be kept 
clean is usually provided for this purpose. In it are storage bins 
for the various raw materials, and scales for weighing these out. 
Materials which are used only in very small quantities are weighed 
out on special balances. 

In small factories the mixing is done by hand in large wooden 
boxes or bins. The various ingredients of each batch are turned 
over a number of times with shovels, or hoes, and are then usually 
passed through a sieve of suitable mesh. In the lai^er factories, 
however, machinery is employed for this purpose. Plate XXII shows 
types of glass batch mixers manufactured by the F. L. Smith Com- 
pany of Milwaukee, Wisconsin, which have found a rather wide spread 
usage in the glass industry. This type of mixer consists of a revolv- 
ing, double conical shaped, drum, inside of which are placed blades 
riveted at an angle to the central axis. These blades are arranged 
in V shaped sets, to pick up, spread out, and turn over the batch. 
The material is charged into the drum at one end through a feed 
chute or batch hopper, and is discharged at the other end by tilting 
the mixer a' hile running. 


Pig. 2. No. 117 Smitli Glnfw Butdi Mixor disriliarginf;. 



, FUEL. 

In the early days of the glass industry furnaces were fired with 
solid fuel, such as coal an<? wood. Later, however, with the dis- 
covery of large gas and oil pools in various parts of the United States, 
especially in Pennsylvania and West Virginia, these furnaces were 
almost entirely replaced with ones in which gaseous fuel is em- 
ployed. This type of fuel has many advantages over solid fuels, 
especially in the manufacture of glass. There is no ash or dust to 
contend with, and the burning is easy to control, so that furnace tem- 
peratures can be easily regulated. This is a factor of great import- 
ance in glass manufacture. 

Natural gas is the best fuel of this type on account of its high cal- 
orific value. The great glass manufacturing centers of the United 
States have, therefore, sprung up where there has been an abundant 
supply of natural gas available. In recent years, however, with the 
gradual exhaustion of the older gas fields and the constantly increas- 
ing demand for gasseous fuel by various industries and domestic 
uses with the consequent increase in the price of natural gas, there 
has been a growing tendency to replace natural gas by producer gas 

made from coal. 

Natural Gas. 

Natural gas is colorless and practically oderless. It burns readily 
with a luminous flame and is the most valuable of the gaseous fuels 
from a heating point of view. In composition it consists chiefly of 
methane or marsh gas (CH^), but higher members of the paraffin 
series of hydrocarbons, such as ethane (CaH^) and olefine (C2H4) 
are also frequently present in small quantities, as are carbon mon- 
o^^ide (CO), and carbon dioxide (COg) and varying amounts of nitro- 
gen, and oxygen. 

' ! 


Analysis of Natural and Producer Gas", 

















Marah saa (CH4) 

Other hydrocarbons. 


Carbon dioxide. 

Carbon monoxide, 


Hydrogen sulphide 


British thermal units per 1,000 cubic feet, - 
























.00 I 

100.00 j 
















80. U. S. Geological Survey. Mineral Resources of the U. 8. 1006. p. 807. 

One British thermal unit indicates the heat necessary to raise one 
pound of water at 39°P one degree. 

Oil and gas are, with few exceptions, always found in sedimentary 
rocks. There is usually, at least, a little gas found associated with 
oil, but at times the gas occurs alone. The two may occur in sepa- 
rate beds, or in different parts of the same bed, having accumulated 
in the pore space of the rocks, or in joint planes, or other cavities. 
The bed containing the oil or gas is known as the oil or gas rock, or 
sand. Usually this is a porous sandstone of varying coarseness, but 
occasionally porous limestones or fractured shales act as reservoirs. 
The portion of the formation which contains the oil or gas is known 
as the oil or gas pool. There may be several pools in one district, 
and likewise several formations lying at different levels that contain 
oil and gas. The thickness of the producing beds may be anywhere 
up to seventy-five or one hundred feet, or even more. The depth of 
the producing formation below the surface also varies greatly. 

Oil and gas are usually found under pressure, so that as soon aa 
the stratum containing them is penetrated by the drill they rise to the 
surface. This pressure often amounts to several hundred pounds 
per square inch when a field is first opened up, but gradually di- 
minishes as more wells are drilled and the oil and gas are extracted. 
The yield of different wells and pools varies greatly. 

The structure of the rocks usually determines the position of the 
pools in any particular district, the oil and gas being found in the 
highest portions of the productive beds, associated with any arch like 
structure, or anticlines, that may be present. Other types of struct- 
ure, however, may also determijje the position of the pools, and 
whether the oil and gas sands are saturated with water is another 
factor which influences their location. 


taken from the reports of the United States Geological Survey on 
Mineral Resources. The quantities g^ven are in units of one thou- 
sand cubic feet and the average price per thousand cubic feet for 
the same period is also given. The accompanying diagram, plates 
XXV and XXVI illustrate the increasing tendency of the consump- 
tion to exceed the production, and the gradual increase in cost of 
the natural gas on this account and also on account of the gradual 
diminution in yield of the gas fields. 

Natural Gas Produced and Consumed In Pennsylvania from 1900 to 1914. 
(Compiled from Natural Resources Reports of U. 8. Geological Survey.) 
















& • 







1900. — . 

1901. ... 
1903, — . 


1904. — . 
1906. ... 

1906. — . 

1907. — . 

1908. — . 

1909. — . 

1910. — 

1911. — . 
1918, — 


1914, ... 
















According to statistics collected by the Topographic and Geologic 
Survey of Pennsylvania in co-operation with the United States 
Geological Survey, of its own production of natural gas in 1914 Penn- 
sylvania consumed 95,889,861 M. cubic feet, the remaining 12,604,526 
}/L. cubic feet, valued at $3,576,605 being marketed in New York, West 
Virginia and Ohio. Of its enormous total consumption, 68,944,681 
M. cubic feet, valued at ?1 1,61 4,634 was piped into the State from ad- 
joining states, almost entitrely from West Virginia. 

The greatest prospect for future development of natural gas in 
Pennsylvania lies in drilling to deeper sands. At present it no 
longer seems likely that new gas fields of importance will be found 
in the State, but a number of old gas fields threatened with extinc- 
tion because of the exhaustion of the gas in the producing sands, 
have in recent years been rejuvenated by drilling to deeper sands, 
and further development along this line may be looked for. 

Producer Gas. 

Producer gas is a combustible mixture of several simple and com- 
pound gases, the chief ones of which are hydrogen, carbon monoxide, 




ed.oo 0.000 

eo. 00 0.000 


/ Volua of production. 



? 500.000 

1900 1901 1902 1903 1304 /^OJ 1906 1907 iSOfl J903 13l0 I9l| IBIH |9k3 IBI^ 


Disif^ram showing tin* valuo of natural gas produced and consumed in Penn- 
sylvania, during the i)eriod 1900 to 1914. 

100.000,000 M Cw. rn 

Constifmption in M Cu Ft. 

15 ©."o 00.000 ^v 




Production in M Cu Ft. 



80.00 0.0 

eo. 000,000 


1906 1907 I90e 1909 1910 1911 1912 IdlO 1914^ 


Diagram showing the amount of natural gas produced and consumed in 

Pennsylvania during the i»oriod 1906 to 1914. 



carbon dioxide, and nitrogen. It is manufactured by means of 
drawing by natural draft, or a fan or blower, air through a fuel bed of 
certain thickness confined in a fire brick lined steel shell, known 
as a producer. Some steam is also admitted in the process. Plate 
^XVII illustrates one type of gas producer. The entering air com- 
bines with the carbon of the bottom layer of fuel, which has been 
heated to incandescence, and carbon dioxide is formed (C+02==C02). 
This is a gaseous, non combustible product of complete combustion. 
It passes up through the higher layers of fuel and is reduced to car- 
bon monoxide (C+C02=2CO). This is a combustible gas, and is one 
of the principle constituents of all producer gas. A minimum tem- 
perature of lOOO^C is necessary for a perfect reduction of the carbon 
monoxide, although a partial reduction takes place at temperatures 
even as low as 450°C. 

Carbon monoxide has a comparatively low heating value. It has 
been found that by blowing a mixture of steam and air, instead of 
pure air, through the fuel bed, a gas of much higher thermal value 
is obtained. When the steam reacts with the incandescent fuel it 
is decomposed, and carbon monoxide and hydrogen are formed 
(C+H20==CO+H2). The hydrogen has a much higher calorific 
power than the carbon monoxide. Considerable nitrogen is added to 
the gas from the air passed through the fuel, and some of the car- 
bon dioxide always remains undecomposed. 

The following analyses, taken from Bulletin No. 13, United States 
Bureau of Mines, page 14, illustrate the composition of producer gas 
made in the same plant from two types of fuel. The analysis of 
natural gas quoted is taken from Power Gas and Gas Producers by 
J. C. Miller, page 35. 

Analyses of Producer Gas. 


00 O 



a a 

s • 



&« . 

as f 


O ] 


s « 


Oarbon monoxide, — — 




Carbon dioxide. — - — 


British thermal units per cu. ft.. 





















The composition of producer gas varies greatly, depending upon a 
large number of different factors, such as the type of the prod 


used and the method and skill of operating it, the uniformity and reg- 
ulation of the air and steam supply, the kind and quality of fuel used 
and the depth of the fuel bed, and its distribution and uniformity. 
The heat value of a producer gas is determined by the relative pro- 
portions of hydrogen and carbon monoxide which are present in the 
gas. The methane and ethylene are also combustible gases and pro- 
duce heat. The nitrogen, carbon dioxide, and oxygen, on the other 
hand being non combustible add nothing to the heat value, but act 
as dilutents. 

As has been alraady stated a temperature of not less than lOOO^C 
is required for the complete tormation of carbon monoxide. Tempera- 
tures higher than this, however, are not* desirable, as they result in 
a rapid destruction of the fire bnck lining and in the formation of 
slag from some of the ash, which is difficult to remove from the types 
of producers in common use today. The temperature at which the 
formation of slag gives trouble depends upon the composition of the 

In order to reduce the fuel bed temi)erature, which otherwise might 
become too high for successful commercial operation, especially when 
bituminous coal is employed, water in the form of steam is added 
to the gassifying air. This not only lowers the temperature but 
increases the thermal value of the gas. Its decomposition to hydro- 
gen, with the formation of carbon monoxide, has already been referred 
to in a previous paragraph. This reaction consumes considerable 
heat, which results in the lowering of the temperature of the fuel bed. 
The reaction is also most complete at a temperature of about 1000°C. 
At lower temperatures more and more carbon dioxide is produced, 
and some of the water remains unchanged, and thus increases the 
moisture content of the gas. This moisture in the gas if present 
at the time of combustion consumes heat, and, therefore, lowers the 
heating value of the gaa Care must, therefore, be exercised in using 
steam to prevent the chilliug of the fuel bed to such a point that the 
necessary decomposition of the steam cannot take place. The amount 
of steam that can be used to advantage, therefore, is comparatively 
small. In the case of bituminous coal Nagel gives it at from 150 to 
200 grams of water per cubic meter of air introduced. 

In the upper portions of the fuel bed, especially when bituminous 
coal is used, considerable volatile matter as well as some tarry ma- 
terials are distilled from the fresh coal by the heat of the gases which 
rise up through it. With bituminous fuels, therefore, too high a fuel 
layer is not to be used, as this causes an increased formation of the 
tar and soot, because the moisture and volatile matter will have time 
to escape from the higher zones before the material reaches the in- 
candescent zone of reduction. For three-fourths inch bituminous 
coal about twenty-two inches is the proper height, according to Nagel, 



while for nm of mine sixty to eighty inches is not too much. The 
higher the temperature of the upper layers the less tar wiU be pro- 
duced, and the more hydrogen and methane will be found in the gas. 
The two latter components increase the thermal efficiency of the gas, 
while the tar is an undesirable impurity. It has to be removed where 
the gas is to be used in gas engines, but when it is used for fuel, this 
is not generally done. 

The simplest type of gas producer consists of a vertical shaft built 
of fire brick and surrounded by an iron shell. The top is sometimes 
made of an arch of fire brick, but frequently it is only provided with 
water cooled covers made of iron. It is furnished with hoppers for 
charging fresh fuel. The shaft is usually circular, with vertical 
walla The fuel moves downward in this shaft while the air and 
gas travel upwards. The gas formed passes up through the green 
fuel, carrying along water and volatile matter, and is led off through 
a large pipe at the side of the shaft, near the top. 

Poke holes are generally placed in the cover and side walls that the 
layers of fuel may be stirred up from time to time and any clinkers 
which may tend to form broken up. The' charging of tr€8h. fuel is 
generally done through a bell hopper in the cover of the producer (See 
Plate XXVI II, Figure 1). In these hoppers the fuel is first placed 
in an upper nopper space, separated from the producer proper by an 
air tight bell. Then the upper door of the hopper is closed and the 
bell opened, allowing the change to run ito the producer. In this 
type of device the charging is intermittent. Various devices for 
continuous charging have been tried. One of the simplest ways to 
accomplish this is to provide the producer with two hoppers. 

A number of devices for removing the ash and clinkers from the 
producer are in use. This has always proven a difficult problem. 
The aim has been to reduce the manual labor and decrease the loss 
of combustible through the ash. Grates for holding the fuel bed 
have been largely done away with in gas producers because their life 
is short, and the removal of clinkers from them is a very tedious and 
difficult operation. Another disadvantage is that during the period 
in which the clinkers are being removed the producer has to shut 
down. In modern continuous producers the ashes and clinkers are 
removed during the operation of the producer. This is affected 
either by a water seal or by mechanical draught processes. 

The draft in nearly all cases is produced by means of a steam jet 
blower. Plate XXVIII, Figure 2, illustrates one type in use. Steam 
jet blowers when properly constructed have the advantage of being 
easy to regulate, and not get out of order readily. Also each pro- 
ducer is independent with respect to blast when equipped with this 
type of blower. 

Plate XXVII shows a cross section of a Bradley Gas Produ 


manufactured by the Duflf Patents Company, Inc., of Pittsburgh, 
Pa, Figure 1, Plate XXIX, shows this producer as it appears when 
set up over a water seal. The fuel bed is supported by its own ash, 
which rests on the bottom of the water seal, which completely seals 
the base and prevents the leakage of gas or air. The ash is shoveled 
out of the water sealed bottom from time to time, no skUled labor 
being necessary for this operation. No heat is lost in the ashes 
taken out, such heat being utilized in the formation of steam which 
rises up through the fuel, and, therefore, lessons the amount of steam 
required for blowing. Thei^ are two sets of grates running parallel 
with the steel water pan and from wall to wall. A dividing plate is 
provided in the center of each grate for the purpose of securing four 
separate and distinct blasts from four steam jet blowers. The grates 
are provided with numerous slots for the distribution of the air. 
l^iis results in an uniform and even combustion of the coal and also 
gives a perfect control over the temperature in the different parts of 
the furnace. 

Plate XXIX, Figure 2, illustrates the Duff Gas Producer as manu- 
factured t^y the H. L. Dixon Ck)mpany of Pittsburgh. This is very 
similar to the Bradley. These producers are made in two sizes. 
The standard has a shell ten feet in diameter and 11 feet in height ; 
measures 7 feet by 7 feet inside of the lining and has a steel water 
pan 7 feet wide. It has a brick arched top, provided with one cen- 
tral bell hopper and six poke holes. The large size has a shell 12 
feet 3 inches in diameter and 11 feet 6 inches in height, measures 7 
by 9 feet inside the lining and has a steel water pan 9 feet wide. It 
has a brick arched top provided with two bell hoppers and nine poke 
holes. There are two blow pipes. The shells in both sizes are con- 
structed of 3-16 inch gauge material. 

Plate XXX shows the standard type of Hughes producer, manu- 
factured by the Wellman-Seaver-Morgan Company of Cleveland, Ohio. 
This producer consists of a revolving brick lined shell with water 
seals at top and bottom, enclosing the coal to be gasified', an ash sup- 
port attached to and revolving with the shell, carrying a blower sup- 
plying steam and air, and water-cooled top plate with a depending, 
vibrating, water-cooled poker. In operation the incandescent zone 
of fuel rests upon a bed of ashes extending from the ash pan to a 
point ranging from 6 to 10 inches above the blower hood. The in- 
candescent zone is from 10 to 30 inches deep, according to the demand 
for gas, and the consequent condition of the fire. Over this, green 
coal is spread to a depth of 4 to 8 inches. The water-cooled poker, 
supported by the stationary top of the producer, and extending 
through the green coal zone and partly into the incandescent zone, 
moves in an arc between the center of the pirodncer and a point within 
a few inches of the shell lining. As the poker swings backward and 


Hiift Ens pniiliiper (rlrvntiuu 


Hughes i)roilu<*r (stamlard tpyi 

Mp<:liDiii('ul[)' HtirriHl iirixlu^T. as built by R. O. Wood and Co. 


forward, the pniducer shell slowly revolves, so that the path in the 
fuel taken by the poker forms a series of ellipses. This prevents in- 
equalities in the fuel bed due to uneveness of feed and blow holes 
which tend to develope in the incandescent zone. It is also designed 
to overcome the dilDeulty experienced with many bituminous coals 
which tend to coke. These coals tend to become semi-plastic during 
the coking process and form a more or less solid mass which inter- 
feres with the free discharge of the gas generated. The revolving 
firie bed and mechanical poker keep this mass disintegrated. There 
are two types of the Hughes Producer, a standard type in which the 
ashes are discharged through a water seal, and a self cleaning type. 

Another type of gas producer with mechanical stirrer is shown in 
Plate XXXI. This is built by the R. D. Wood Company of Phila- 
delphia. It also consists of a lower revolving shell with a water seal 
at the top and bottom, and an upper stationary one with an arched 
fire brick top. There .are two water cooled stirrer bars, whose lower 
portions are curved to permit a thorough agitation of the fuel bed. 
These bars are given a rotary motion by means of worm gears while 
at the same time the whole fuel bed is revolving about a central axis 
with the rotation of the lower portion of the producer. This keeps 
the material thoroughly disintegrated and tends to prevent the forma- 
tion of clinkers. A plough attached to the rotary shell removes the 
ash uniformly and discharges it at a fixed point. 

All the producers described are designed for the use of bituminous 
coal, which is the principal fuel used for making producer gas in 
Pennsylvania. Plate XXXII shows the distribution of the coal fields 
of Pennsylvania by fuel ratios. 




Two types of furnaces are used in the manufacture of glass, namely, 
pot furnaces and tank furnaces. In the former the glass is fused 
either in open or closed pots, while in the latter it is fused in large, 
usually rectangular shaped, open hearths. 

Fire Clay. 

Pots for pot furnaces and blocks for tank furnaces are made from 
special grades of refractory clay, which according to Bies should 
conform to the following requirements.'^ 

1. Sufficient refractoriness to withstand the highest heat used, 
without changing form. 

2. Great plasticity, such that the addition of 50% to 60% of grog 
will not affect it appreciably. 

3. The clay must bum dense at as low a temperature as possible. 

To these may be added that the clay should have little tendency to- 
wards the separation of substances from it which will contaminate 
or color the glass, and also that it must possess toughness and have 
low air and fire shrinkage. 

A clay is generally considered sufficiently refractory for making 
glass pots if its fusion point is the same as that of cone 30, approxi- 
mately 1,690°C, or 3,074^P. In judging the tensile strength, the 
size of the grog grains must be considered, and the relation in which 
the different sized grains are mixed. Olass pot clays should bum 
dense at a low temperature, so that when grog is added the tempera- 
ture will not have to be raised too much to get the required density. 
The addition of grog raises this temperature, the extent depending 
upon the amount added. 

Plasticity, shrinkage, temperature at which the clay burns dense, 
fusion point, and chemical composition are the properties of a clay, 
therefore, which must be investigated in order to determine its value 
for glass pots or tank blocks. Clays that fulfill all these conditions 
satisfactorily are comparatively rare in the United States. Thus far 
clays for this purpose have only been mined to any extent at St. Louis, 
Missouri, and Mineral City, Ohio. They are also known to occur in 
Pennsylvania and are undoubtedly present in other states, but up to 
the present time these have not been thoroughly tested. Before the 
present European war large quantities of glass pot clays were an- 
nually imported into this country from Germany and Belgium, but 
as this supply has now been temporarily cut off, and the stock of 

27. Bnllettn New York State MuMom, No. 86, 1900, pp. 780-787. 


foreign clays on hand is becoming exhausted, American clays are be- 
ing substituted with satisfactory results. So far as known no one 
American clay possessea all the requii*ed qualities, but it is a rather 
easy matter to so combine clays, each possessing some special quality 
or qualities, as to obtain a combination which is 'superior to any of 
the imported clays. 

The fire clays of the St. Louis district, Missouri, are derived from 
an area which has its center in a section of the western portion of 
the city, known as Cheltenham, lying south of Forest Park, and ex- 
tends southward into St. Louis County.^* Tlie geologic feature to 
which the presence of the fire clay within this area is mainly due is a 
faint geological basin. In this basin a little of the Pennsylvanian 
coal measures, usually less than one hundred feet in thicknd^s, have 
been preserved from erosion. The coal measures here lie discon- 
formably upon the St. Louis limestone of the Lower Carboniferous or 
Mississippian period. The coal measures consist mainly of shales 
and clays, with subordinate beds of limestone and a few thin beds of 
coal. At the base is a thin, but persistent, sandstone which forms 
the floor of the fire clay mines, all of which are in the very persistent 
overlying bed of fire clay, known as the "Cheltenham seam." The 
clay is secured much after the manner of coal mining, both shafts and 
slopes being operated. The depth below the surface is usually about 
seventy-five feet. 

The thickness of the main, or "Cheltenham" bed varies greatly, 
ranging from one to twelve feet within a small fraction of a mile, but 
it rarely, if ever, pinches entirely out. Most of the mining is done ' 
where the thickness ranges from three to eight feet. Where it ex- 
ceeds that thickness, as at the northeast comer of Cheltenham, the 
mining is generally limited to about eight feet from the best part of 
the bed. Near the center of the area, or within one mile to the south 
of it, the bed generally ranges about seven feet in thickness, all of 
this being good clay and taken out. At places the bed is mined where 
it has a thickness of only two and one-half feet. 

The clay bed is rarely of uniform quality throughout its entire 
thickness. Its usual variations are due to changing proportions of 
silica and carbonaceous matter, and to the presence or absence of 
pyrite and other iron minerals. In the westeni part of the field py- 
rite, the chief impurity, is found mainly in the upper part of the bed. 
The best grade of pot clay occurs in the Oak Hill district about one 
mile south of Cheltenham. 

Only the best of the clay is used for tank blocks and glass pots. The 
clay is carefully sorted in the mine and on the surface. Part of the 
clay is pure enough to be used in the crude condition, while another 

28. U. S. Ocologlcal Surrey, Bull. 316, 1907, pp. 81S-321. TruiBactloni Anierlc«n Cenunl" 
SoclPtf, Vol. XVI, 1014, pp. 101-108. 


grade is allowed to weather on the surface and is then washed and 
put on the market in raw and burnt blocks, or ground to various de- 
grees of fineness. The clay remaining after the selecting and picking 
is used in the manufacture of other products, such as brick, where the 
highest grade of clay is not required. The following analysis is that 
of a plastic fire clay from St. Louis, Missouri.^* 

Analysis oX Fire Clay from 8t. Louis, Mo. 

8iO, 67.62 

AltOa - 24.00 

FeaO. 1.90 

FeO 1.20 

CaO .70 

MgO 30 

K,0 50 

NaaP -. .20 

H.O. - 10.50 

Moisture 2.70 

SOs, 35 


The Mineral City, Ohio, flint clay, which has been used in the man- 
ufacture of glass pots and tank blocks occurs at the Lower Eittan- 
ning horizon of the Allegheny formation of the Pennsylvanian period.** 
It lies at varying distances below what is called Number 5 coal in 
Ohio and does not form a continuous bed, but occurs rather in len- 
ticular shaped masses which range from four to five feet in thickness 
down to nothing, often pinching out suddenly and reappearing again 

In color this clay is a shade of gray, tending towards brown rather 
than blue. It is very hard and flinty, breaking like glass, and showing 
a conchoidal fracture with smooth surface. 

The clay is won by mining and sent to the screening house where 
it is screened and hand picked. All doubtful lumps are broken into 
pieces with small hammers and any impure clay present is carefully 
removed. It is then ready for grinding. The clay is used in the 
manufacture of both glass pots and tank blocks. It is necessary 
to mix a plastic fire clay with it to serve as a bond. 

Small quantities of clay from Pennsylvania have been used to mix 
with imported clays in the manufacture of glass pots and tank blocks, 
but up to the present time most of the clay used in this industry 
in the State has been imported from Missouri and Germany. Ries'^ 
gives the following analysis of a glass pot clay from Layton station, 
in northern Fayette County:. 

29. Kronomio OpoIojtt, Rn!. edition, by Hotnrlch RIer, p. 129. 

80. Transactions American Ceramic Society, Vol. 8, 1906, pp. 853-398. 

81. U. S. Geological Surrey, Professional Paper 11, 1003, pp. 40-41. 

Analysis of (Jlass Pot Clay from Payette County. 

SiO. 64.89 

AlaOa 24.08 

Fe.Oa 29 

FeO. 21 

CaO - 41 

MgO ~ 19 

Alkalies _ 1.08 

H,0 9.29 


Much of the glass pot clay imported from Germany comes from 
Oross- Alma rode. Here the refractory clay beds are from 32 to 42 
feet in thickness.** The clays are of Tertiary age and according to 
Ries consist of the three following types: 

1. Upper or pipe clay. 

2. Crucible--clay. 

3. Olass pot clay. 

Numbers 2 and 3 are less fat than 1, and form the main deposit. 
The former is the most important and the most refractory, its prop- 
erties being such that it will stand great additions of grog and sand 
to diminish the shrinkage without too great loss of plasticity. It 
is used in the manufacture of crucibles. The upper or pipe clay is 
used in the manufactilre of jugs, common cooking utensils, bricks and 
roofing tile. There are several grades present. The glass pot clay 
has the following composition : 

Analysis of Glass Pot Clay from Gros-Almarode, Germany. 

SlOt present as sand grains _ 6.53 

SiOa. combined - 43.38 

AlaOa - 34.52 

Fe,Oa 1.66 

CaO - 76 

MgO 37 

KaO 1.51 

SOa 26 

Loss on Ignition 11.04 


The best grade of glass pot clay mined is not purified before ship- 
ment. It is a clay of great density, plasticity and fair refractori- 
ness. An important property is that it bums dense at a compara- 
tively low temperature. Tests made on an air dried sample, when 
mixed with 25.80% of water gave an extremely tough paste. The 
bricklets made from it had an air shrinkage of 5.95%. At cone 09 
(970^C or 1,778°F) the shrinkage was 11%. It is practically im- 
possible to bum the clay without grog and prevent it from cracking. 
The clay is not a highly refractory one, for according to Pi'ofessor C. 
Bishop its fusibility is very little above that of cone 27 (1,670^C or 

Silica Brick. 

Silica brick is another refractory material used in the glass in- 
dustry. They are employed in the construction of arches in fur 

83. U. S. Oeoloflcal Bnrrey. 19tb. Animal Report, p«rt 6, p. 418. 



naces. Silica brick are made from a nearly pure quartzite or "gan- 
ister^' as it is called by the brick maker. The quartzite should con- 
tain at least 97% silica and very little iron. The sand grains must 
be thoroughly cemented by silica so that the rock will tend to break 
across the grains rather than along the bond. In central Pennsyl- 
vania large quantities of this material are found in what is known 
as the Tuscarora sandstone of the Silurian system, the so-called Me- 
dina sandstone of the Second Geological Survey. 

The formation is very resistant to erosion and, therefore, forms the 
ridges or mountains of the central part of the State. Much of it is 
a quartzite of sufficient purity to be used for the manufacture of 
silica brick. At the surface it has been broken up into blocks of 
varying size by the several agents of weathering, such as frost and 
daily changes of temperature, so that the ridges underlain by the for- 
mation are usually covered with a mantle of broken rock or talus 
varying in thickness from a few feet up to twenty feet. This talus 
material where it is of sufficient purity and has not been too badly 
disintegrated by the agents of weathering is used in the manufacture 
of silica brick. Sometimes quarries are also opened in the massive 
rock itself underneath the talus material. The rock is first crushed 
in a jaw crusher and is then ground in a wet pan. About two per 
cent calcium oxide, in the form of milk of lime, is added and thor- 
oughly mixed with the material in the pan. The brick are then 
moulded from this mixture by hand, in steel moulds. They are dried 
at about 150°C or 400°P and then burned at about 1595° or 2900°F 
in down draft kilns. This changes most of the quartz to cristobolite 
and the lime between the quartz grains is converted into a lime silicate 
which forms the bond. The following is an analysis of burned silicia 

Analysis of Silica Brick. 

RIOs - 96.10 

AUOs -90 

Fe,Os 70 

CaO - 1.80 

UkO .14 

Alkalies 39 


Manufacture of Glass Pots. 

Melting pots used in pot furnaces are of two types, covered and 
open ; the former are used in the manufacture ot lead flint glasses and 
sometimes lime flint, although at present there is a tenikncy to grad- 
ually replace pot furnaces by tank furnaces in the manufacture of 
lime flint glass. The use of open pots is now confined almost en- 
tirely to the plate glass industry, although at one time they were 
also used in the manufacture of window and other varieties of glass. 

33. Mineral IndustiTf toI. 23, 1014, pp. &00-906. 



of KiBtiH pots. (Ohio Vnllnj' Clay Co.) 


PLATE XXX I II sliows a number of different tyi)e8 of pots used in 
various branches of the ghiss industry. 

On account of the severe service which is exacted from glass pots 
their manufacture requires the highest type of technical skill. The 
pots are of various styles and sizes, weighing anywhere from 1500 to 
4000 pounds. These pots not only have to sustain their own weight 
under the high temperature of the glass furnace, but must retain a 
ton or more of molten glass whose ingredients comprise such powerful 
fluxes as the alkalies, lime and oxide of lead. In addition to this 
they are subjected to considerable strain due to unequal contraction 
when sudden chilling of the interior results from the addition of a 
new charge. a*^ 

Three classes of materials enter into the composition of clay pots, 
namely, unbumt clay, burnt clay, and broken pot shells from old pots 
returned from service. The clays are selected with extreme care. 
Sometimes they are used in the raw state as they come from the mine, 
but frequently it is necessary to wash them to remove impurities, as 
has already been stated under the discussion of clays. The burnt 
clay and pot shells are called grog. Extreme care is exercised in 
chipping the old shells free from the adhering layer of glass on the 
inside, and the scorified and incrusted outside portion. These broken 
shells are taken from previously made and used pots whose record has 
been kept, so that their composition is known and no uncertainty of 
composition is encountered in their use. The object of adding burnt 
clay or grog is to facilitate the safe drying of the finished pots by 
diminishing the total amount of shrinkage which occurs when the 
plastic clay is allowed to dry, and afterwards when it is burnt, the 
burnt material having already undergone this shrinking process. The 
grog also acts as a skeleton which strengthens the whole mass and 
reduces the tendency to form cracks. The unburnt clay acts as the 
bond which renders the whole mass plastic, thus allowing it to be 
moulded into the desired shape and causing it afterward to bum to a 
dense product. Considerable quantities of German clay have been 
used for this purpose in the past. 

The physical structure of the clay is a factor of prime importance. 
Two pot mixtures having approximately the same chemical compo- 
sition, but containing different types of clays, will not give the same 
service unless their physical structures are also similar. 

After the raw materials have been carefully selected the next step 
is to grind them to the proper fineness. This is an important opera- 
tion. In grinding the shell care must be exercised that the small 
particals remain sharp, and of the proper size, although the fine 
powder which results from the operation is often used. Dr. Bischof 
is quoted by Dralle as recommending that the grog should be ground 
down to paH^icles one to three millimeters in diameter. In American 


practice the grog is ifsually crushed to a 4 to 8 mesh size, or to par- 
ticles 2.4 to 4.7 millimeters in diameter, and the fine grog is removed 
by passing it through a 10x30 mesh screen. There are two factors 
which determine the size to which the material is ground. First, 
the smaller the grains the denser will be the resulting mass. It is 
important to have this as great as possible for so much more re- 
sistant will be the resulting pot against the fluxing action of the in- 
gredients of the batch and the molten glass itself. On the other 
hand the denser the mass the more sensitive it becomes towards tem- 
perature changes. It is necessary, therefore, that the pot should 
have a distinctly granular structure to resist the strains set up by 
the temperature changes, thus allowing the pot to expand and con- 
tract without cracking. In practice a size must be adopted which 
strikes a mean between these two tendencies. 

The mixture of raw and burnt clay, therefore, are so selected and 
ground to such fineness that they will bum to a density where very 
little granular structure is left, this being just suflBcient to give the 
pot the necessary elasticity to withstand the temperature changes to 
which it will be subjected. The glass always tends to soak into the 
pore space between the grog particles, thereby loosening them, until 
finally they are surrounded by glass and float out, becoming stones in 
the glass. Dr. S. R. Scholes of the Mellon Institute of the University 
of Pittsburgh has, therefore, been experimenting with a vitrified sur- 
face coating for the inside of glass pots to cut down the surface of 
particles exposed and has met with encouraging results. 

After the material has been crushed to the desired fineness the glass 
pot mixture is made up about as follows: 

40% raw clay. 

60% burnt material or grog, consisting of 30% pot shell and 30% 
burnt clay. (Considerable variation exists in the practice of differ- 
ent manufacturers, however, some using as little as 30% raw clay, 
with 70% of grog, while others use as high as 50% of raw clay and 
only 50% of grog. The batch is thoroughly mixed and carried to the 
pug mill, where water is added and it is pugged several times. It 
is next piled up in large masses, compacted by hammering until solid, 
and covered with heavy canvass or sacks which are kept moist. The 
clay is then allowed to undergo a process of sweating or steeping 
which is called "ageing,", and which extends over a period of from 
three to six months, or even longer. This long soaking induces a 
softening of its nature and develops toughness in the mixture. 

When the clay has aged sufficiently to work it is again pugged and 
then sent to the clay trampers. These men tramp the clay with 
their bare feet until it gets the right consistency, sometimes tramp- 
ing it over and over again from fifteen to seventeen times. All stiff 
lumps that would pass through the pugmill are thus detected and 

ri.A'i-r, xxxr 

I KhniiCH of Tank liliti' 


removed. In some factories this tramping by foot has been replaced 
by careful pugging by machinery. 

After the clay has gone thix)ugh the tempering process it is trans- 
ported to the pot rooms, where it is made into small rolls about three 
inches in diameter and six inches long, in which form it goes to the 
pot maker. The first process in making the pot is the laying of the 
bottom. This is sometimes tramped but more often it is laid on a 
large board. The bottom of an average size pot is about four and 
one-half inches thick, laid in four or five lavers of about one inch 
each, each layer crossing the preceding one at right angles. It is 
made of sufficient size to permit the laying out and cutting down to 
the desired outside dimensions of the pot to be made. An ordinary 
covered pot has a heart shaped base with a long diameter of about 
sixty inches and a short diameter of forty. After it has been beaten 
down and cut to the shape desired the board, with the adhering slab 
of clay, is turned upside down on a special board, which has a Hning 
of plaster of paris and a coating of sand which allows the pot to 
creep as it shrinks in drying. This shrinkage amounts to one and 
one-half to two inches, according to the size of the^pot. The slab 
of clay is then cut from the original board with a wire strand and 
the mass of clay forming the bottom of the pot now rests on the 
special board. 

The pot is then ready to be started from the bottom. This is first 
scratched to make a rough surface that the clay will adhere to it. 
The clay of the sides is then put on in a series of hand and finger 
courses, each working being about three-eights to one-half inch in 
thickness. These workings alternate, first one on the inside and then 
one on the outside, until the proper thickness is reached, which is 
about four and one-fourth inches at this point. This is carried on 
until a height of from six to eight inches is reached. The pot is then 
covered with a towel and allowed to remain a few days until it has 
stiffened up sufficient to hold the next working, which is called the 
"second working.^' Plate XXXIV, Figure 1, shows several pots at 
this stage. The operation is repeated, working about six to eight 
inches at a time until the pot reaches the point where the crown is 
to be turned. The first spell of the crown is called "turning the 
shoulder." After a few days wait, until the sides of the pot will 
hold up, the crown is worked on in two or three workings, and is 
beaten down into shape with a glass beater. 

When the clay is closed in at the top of the pot it encloses a quant- 
ity of air inside the pot, which being somewhat compressed, tends to 
support the crown until it has had time to dry. Care must be gxer- 
cised to let the air out at the proper time or it will cause the pot to 
crack. This is done by making a small hole at the point where the 
pot mouth is to be made. 


The pot is now ready lor the hood. The pad forming its lip is put 
ou first, tlien the pot mouth is cut and the crown is smoothed on the 
inside, after which the hood is smoothed. The pot is now finished 
and the process of drying starts in. The pot is left on the board for 
several weeks and is then taken off and set in such a position that the 
bottom can dry. After the pot is sufficiently dry to move it is stored 
away in a warm room, where it stays from four to six months before 
being shipped. An even temperature of about 68°F is maintained 
throughout the year as the proper drying temperature, while hydro- 
meters are used to register the amount of moisture that the air con- 
tains, so that this can also be maintained at the proper point. Ex- 
cessive dryness or dampness is taad for drying poto, while- draughts 
or air currents passing through the room are fatal. After the pots 
have passed through this drying process they are ready to ship to 
the glass house. They are not burned until they reach their final 

The process of making a glass pot is a very slow one taking any- 
where from one month to six weeks. Each pot maker has from six- 
teen to twenty pots under his care at one time, working the clay on 
from five to six pots each day. 

Open pots used in the plate glass industry are made in a very 
similar manner, except that they are open at the top and have a 
tapering circular shape. Usually a slightly different mix from that 
used for closed pots, especially those used in the manufacture of 
lead glasses, is used for open pots on account of the difference in flux- 
ing action of the two types of ingredients going into these two va- 
rieties of glajss. 

Pot Furnaces. 

The general arrangement of a pot furnace for closed pots is shown 
in Plate XXXV, while Plate XXXVI shows the exterior appearance 
of such a furnace on the working floor. This type of furnace is em- 
ployed where a glass of good color is desired and where it is neces- 
sary to exclude furnace gases from the glass to avoid a reducing at- 
mosphere, as is the case in the manufacture of lead glasses. 

The regenerative type of furnace is now almost universally used in 
the manufacture of glass so as to utilize the waste heat of the gases 
escaping from the furnace in preheating the incoming air and gas. 
In thiis type of furnace the hot products of combustion, after leaving 
the furnace chamber proper, pass through chambers which are filled 
with loosely stacked fire brick, before reaching the chimney as shown 
in the illustration. The brick absorb the heat from the escaping 
gases and become heated to a temperature of about lOOO^d After 
an interval of about twenty to thirty minutes the path of the gas 
currents is altered. The incoming air and gas are now drawn 
through the heated brick checker work while the products of com- 


SrationthroDgh a regenerative pot furnoM. 


bastion are made to pass through a second set of regenerator cham- 
bers. The incoming air and gas are thus heated by absorbing the heat 
stored on the brick work of the regenerators. Two sets of regener- 
ators are thus necessary for each furnace. While one set is being 
heated by the escaping gases from the furnace, the other set is giv- 
ing up its heat to the incoming air and gas. 

In a pot furnace the "ports" or apertures by which the air and gas 
enter the furnace chamber are placed in the floor of the chamber as 
shown in the illustration. There are two of these "ports." The 
gas and air enter at one, combustion occurs, the flame strikes the 
crown of the furnace, is deflected so that it plays about the pots, and 
then the gases of combustion leave by way of the second aperture. 
As has already been stated in the case of a regenerative furnace the 
direction in which the gases enter and leave the furnace is reversed 
every twenty to thirty minutes. 

When a new pot is to be set in the furnace it is first heated slowly 
to the temperature of the working furnace in an annealing arch, or 
"pot arch" as it is called. It is then moved and set in the furnace 
proper as lapidly and with as little cooling as possible. After the 
pot has once been set in the furnace it is not allowed to cool again 
unless the furnace has to be shut down for repairs. A pot has an 
average life of about three months, although some pots may last as 
long as ten months. Pot furnaces are built to accommodate. any- 
where from ten, twelve, fourteen to twenty pots. These furnaces ai'e 
usually run at temperatures of from 1400° to 1500°C, or 2552° to 

The open pot furnace used in the manufacture of plate glass are 
rectangular in shape. They have a vidth of about three times that 
of a single pot and are usually made so as to hold twenty pots, ten 
on a side. Such a furnace is about forty-nine feet long, twelve feet 
wide, and five feet high on the inside. Opposite each pot is an open- 
ing large enough to allow the pot to be conveniently removed from 
the furnace for casting. This is kept closed by a fire clay door. 

The air and gas flues come up at either end of the furnace and 
terminate vertically, or they come up vertically above the hearth level 
and turn so as to enter the furnace horizontally. The flame travels 
from one end of the furnace to the other, describing the arc of a cir- 
cle. As regenerators are almost always installed the direction of 
the flame is reversed every twenty or thirty minutes. The regenera- 
tors are usually placed underneath the furnace, but they are so 
located that the occasional breaking of a pot will not allow the con- 
tents to pour into them. Pockets are placed underneath the fur- 
nace in which the glass resulting from such accidents may be caught 
and removed. 

The life of an open pot is considerably shorter than that of a closed 


pot, on account of the more severe useage to which it is put. The 
average life of an open pot is about six weeks. Open pot furnaces are 
heated to temperatures of from 1450° to 1540°C, op 2650° to 2800°F. 

Manufacture of Tank Blocks. 

Tank blocks are used in lining those portions of a tank furnace 
which come in contact with the molten glass. The requirements of 
a good block are that it must have high refractoriness, it must be 
able to resist the fluxing action of the ingredients used in making 
glass, such as lime, salt cake, etc., and the molten glass itself, it must 
be able to withstand the wearing action of the moving glass, and it 
should be a good non conductor of heat. The density of the block 
is also an important factor. It must be sufficiently dense to resist 
the fluxing and wearing action of the glass and yet not so dense as 
to allow cracking or checking on account of changes in temperature. 
The block must also be well burned before it is placed in the furnace, 
so as to reduce shrinkage. 

Tank blocks are made in a large number of sizes, varying anywhere 
from 24x15x8 inches or smaller, up to 120x30x18 inches. They weigh 
anywhere from 50 to 3,000 pounds. As* very few glass tanks are built 
exactly alike, each one necessitates a complete set of moulds for every 
block used in its construction. 

The manufacture of tank blocks is a rather simple process when 
compared with the making of pots, but the same care must be em- 
ployed to prepare a material which will withstand the wear to which 
these blocks are put in a tank furnace. The selection, grinding, pre- 
paring, and pugging of the clay is practically the same as that for 
pots, and very much similar mixtures are used. 

After grinding, the clay mixture is tempered in wet pans to a cer- 
tain consistency, learned by experience, for the particular clay used. 
After it has been tempered it is packed in bins and allowed to age. 
The longer this curing process lasts the better the clay will work. 
It is then run through a pug mill and comes out in the shape of cylin- 
ders about six inches long and three inches in diameter, ready to be 
taken to the moulding room. 

The moulds simply form the four walls of the block.^ These are lined 
with water soaked clothes. The clay cylinders are thrown into the 
molds, one at a time, pounded firmly with the hand and carefully 
kneaded with the fingers to insure density, homogeniety and freedom 
from laminations and air holes or cracks. Sometimes the clay is 
tnmped into the molds with pneumatic rammers, operating at an 
air pressure of 80 to 100 pounds. 

As soon as the block is moulded the frame is removed and the block 
is covered with a cloth. It is allowed to stand until it has become 
leather dry. Then it is turned up on it side to allow the bottom to 

After Gillioder: 

Horizontal section of a continuous glass tank. 


dry. The drying is done on floors which are heated from above, 
rather than from below, by steam pipes. This insures a more uni- 
form temperature. 

After drying the blocks are dressed to a given size, the angles be- 
ing made true right angles and the faces being also trued up. Most 
of this work is done by hand with two edged axes and chisels. Finally 
the block is finished to the square and straight edge with a rubbing 

After dressing the blocks are ready to be burned. In the case of 
large blocks the drying is finished in the kilns. Round, down draft 
kilns are used. Great care must be exercised in this operation. The 
water smoking requires from one week to ten days or more, depend- 
ing upon the dryness of the blocks. When the steam is all off the 
fire is raised rapidly and finished at a temperature of about 1370°C, 
or 2500°F in from two to three days. 

Two grades of blocks are used in the tanks, one known as the com- 
mon or furnace grade, and the other as the flux line grade. The 
furnace grade blocks are used in the bottom and part way up the 
sides where the glass is very viscous and in a chilled condition, so 
that the fluxing action is not very great, the blocks being thus pro 
tected from the intense heat of the upper part of the tank. The 
flux line blocks are used along the upper part of the sides of the tank 
where the glass is in the most fluid condition and hence most active 
as to its action on the blocks. Plate XXXIV, Figure 2, shows a 
number of different shapes of tank blocks. 

Tank Furnaces. 

Tank furnaces are glass furnaces in which the glass is brought to 
the molten state in large tanks, or basins, constructed of fire clay 
blocks, whose preparation has already been described. These fur- 
naces may be divided into two types, namely : — continuous tanks and 
intermittent tanks. The former are worked continuously and are 
the type in most common use, while the latter are filled with batch one 
afternoon and worked the next day. 

Plates XXXVII and XXXVIII show plan and cross section views 
of continuous tanks and illustrate their general arrangement. Great 
care must be taken that the blocks of the tank fit together perfectly, 
as the glass is sure to search out any cracks or fissures in the retain- 
ing walls. The depth of these tanks ranges from as little as twenty 
inches up to sixty inches in the larger ones. Their length and width 
also varies greatly. Continuous tanks for the manufacture of win- 
dow glass are made over 110 feet long and 25 feet wide. 

The ports for the entry of the gas and air and the exit of the pro- 
ducts of combustion are usually placed in the side walls of the fur- 
nace, just above the level of the glass, but end port tanks are also 


built. B^enerators are provided as a rule, and air and gas come in 
first at one side of the furnace, and then at the other, the products 
of combustion always leaving at the opposite side. This change is 
made every twenty or thirty minutes. The tank itself is covered by 
an arch of silicia brick, as shown in the illustration. 

These brick withstand high temperatures and have great mechani- 
cal strength. On heating they expand instead of contracting, as 
do bricks made of fire clay, which makes them especially valuable in 
the construction of arches in furnaces. Allowance must be made for 
this expansion in constructing the furnace. This can be done by 
gradually slackening the tie bolts that hold the arch together, and 
correspondingly "taking up the slack" as the vault cools when the 
furnace is shut down. Silica brick is rapidly attacked by molten 
glass and, therefore, can only be employed where it will not come in 
contact with the glass itself. 

Continuous tanks, as a rule, are divided by means of fire clay ob- 
structions, or floats as they are called, into several compartments, 
consisting of a melting or charging chamber, a refining chamber, and 
a working chamber. See Plate XXXI X. The batch is charged into 
the tank at one end, and after melting flows under the obstruction to 
the working end. As fast as the glass is worked out new batch is 
introduced at the other end, so that the melting and worthing goes on 
continuously, thus maintaining a n^rly constant level of glass in 
the tank. Continuous tanks are operated at temperatures in the 
neighborhood of 1510°C or 2750^F. The temperature is usually de- 
termined by means of pyrometers, chiefly of the thermo-electric type. 

In the case of intermittent tanks the batch is shoveled into the 
tank and the work holes are closed. Heat is supplied until the glass 
has reached the molten state and frees itself of gas bubbles. Then 
the heat is reduced, the work holes are opened, and when the temper- 
ature has dropped sufficiently the glass is worked. These tanks as a 
rule are filled in the afternoon and are ready to work the following 
morning. For this reason they are often spoken of as "day tanks." ^ 
Such tanks are very wasteful of heat and hence are not used to any 
extent at the present time. 

Relative Merits of Pot and Tank Fumacefl. 

Continuous tank furnaces have a considerable number of advantages 
over pot furnaces which have led to their adoption wherever they can 
be made to produce glass of adequate quality for the purpose desired. 
For this reason practically all bottle and window glass is now pre- 
pared in continuous tank furnaces. On the other hand when special 
qualities of glass are required, in relatively small quantities, the pot 
furnace still remains indispensable. Optical glasses and most col- 
ored glasses are examples of this kind. 


o-|>iece floater. (II. L. Dixi 


Some of the more important advantages of continuous tank furnaces 
over pot furnaces are the more efficient utilization of the heat in the 
former, the greater output for a given size plant on account of the 
fact that the tank furnace is operated continuously, the economy in 
labor, the greater durability of the tank furnace owing to uniformity 
ot temperature as compared with pot furnaces, and, finally, the saving 
in the costs of pots which are much more expensive to replace and 
have a shorter life than tank blocks. 

Pot furnaces have the advantage over tank furnaces, on the other 
hand, in, that the composition of the glass cAn be more accurately 
regulated and the molten glass itself can be more effectually protected 
from contamination from matter dropping into it, and from coming in 
contact with the furnace gases. In the manufacture of <!ertain 
glasses, such as those containing lead, tank furnaces cannot be em- 
ployed on account of the reducing action of the furnace gases and 
closed pot furnaces therefore must be used. 




The process of fusion is conducted in three stages. First, the raw 
materials are heated to a sufficiently high temperature so that the 
ingredients melt and react with one another to form glass. Then 
the temperature is raii^ somewhat to cause the glass to become more 
fluid, thus allowing the gases held by it to pass off more freely. This 
is called the "fining" process. Finally, the glass is allowed to cool 
down to working viscosity. 

After the glass batch has been prepared as described in a previous 
chapter it is ready to be charged into the furnace. In the case of 
pot furnaces the material is charged into a pot which has been al- 
most entirely emptied during the previous working out process. Dur- 
ing this process the temperature has fallen considerably, so it is first 
necessary to raise this before a new charge is added^ or the melting 
will not proceed satisfactorily. During the early stages of the melt- 
ing large quantities of gas are given off which cause considerable foam- 
ing. The raw materials also occupy much more space than the fin- 
ished glass. For this reason the charging cannot all be done at once, 
but fresh batches of raw material have to be added at proper inter- 
vals of time. Sometimes as high as four to eight "fillings" are neces- 
sary when closed pots are used. In the case of open pots one "top- 
ping," after the first charge has melted, is usually sufficient. 

In the case of continuous tank furnaces the introduction of the 
batch into the furnace is a more simple matter, as the temperature 
is kept as near constant as possible. This allows the addition of 
new materials at almost any time. The amount added is so regulated 
that the level of the molten glass in the tank is kept as nearly con- 
stant as possible. The charge is introduced through a large open- 
ing or door at the "melting" end of the furnace, closed by means of a 
large fire brick block, suspended by a chain running over pulleys and 
counterbalanced by a weight. When charging is to begin this block 
is raised and the batch is introduced, either by hand with the aid of 
long handled shovels, or by means of a long scoop moved by mechan- 
ical means forward into the furnace, which is given a half turn to 
empty it, and is then rapidly withdrawn. See Plate XL. 

The exact reaction which takes place in a, glass mixture during the 
process of fusion are not definitely known, but the general lines along 
which these occur may be inferred from the end results and a few of 
the intermediate products that are known. The c,ase of a lime soda 
glass, made from the proper mixture of sodium carbonate, limestone 


and sand; will be considered timt. As the batch becomes heated 
the sodium carbonate is the first to melt. As the temperature rises 
it and the silica, the latter acting as a strong acid at the temperature 
of the furnace, react and sodium silicate forms and carbon dioxide 
is set free as a gas. in like manner the silica attacks the calcium 
carbonate of the limestone and a calcium silicate is formed, which is 
also accompanied by the liberation of carbon dioxide. Finally, all 
the carbonate present is decomposed with the complete liberation 
of the carbon dioxide* The molten glass now consists of a mixture 
of sodium and calcium silicates, probably partly present in a state of 
mutual combination and partly of mutual solution. These reactions 
may be expressed as follows: 


When the sodium is added in the form of a salt cake (NajSO^) a 
more complicated set of reactions takes place. Silica alone, as has 
already been stated, is not able to decompose sodium sulphate suf- 
ficiently rapidly for successful glass manufacture at the working tem- 
perature of the furnace. For this reason a certain amount of carbon, 
in the form of coke, anthracite coal, or charcoal, has to be added to 
the batch. This aids in the reduction of the sulphate and its decom- 
position by the silica. The reaction may be expressed as follows: 

2Na2SO,+4Si02+C=2(Na20 2SiOj+2S02+C02 

In the case of a lead potash glass the silica attacks the potassium 
carbonate of the batch in the same manner that the sodium carbon- 
ate is decomposed in the lime soda glass batch. The silica also com- 
bines with the lead of the red lead (Pb^O^) employed with the forma- 
tion of a lead silicate and the liberation of a portion of the oxygen 
of the lead oxide. The result in this case is a mixture of lead and 
potassium silicates. 

If the batch has been satisfactorily selected and prepared and the 
process of fusion has been properly conducted, as soon as the last 
trace of the raw material has disappeared a transparent mass of 
molten glass results, which has numerous gas bubbles disseminated 
through it. It is now ready for the second stage in the^ melting 
process that is, freeing it from these bubbles. This is done by heat- 
ing it further and to a higher temperature, thereby rendering it more 
fluid and thus allowing the gas bubbles to rise and pass off more read- 
ily. The larger these gas bubbles are the more readily 
they rise to the surface. In fact, in the case of very minute bub- 
bles it is practically impossible to cause them to rise. An attempt 
is, therefore, made to compound such a mixture of raw materials as 
win yield large bubbles. If this is unsuccessful some substance may 


be added to the molten mass that evolves a great many large bub- 
bles, which on rising up through the molten glass sweep the small 
bubbles along with them. An inorganic volatile body, such as arsenic 
trioxide, is frequently used for this purpose, as are certain vegitable 
substances that contain a high percentage of moisture, such as pota- 
toes. In this case the potato is usually placed in the crook of a 
forked iron rod and is dipped into the molten glass. The heat at 
once begins to drive off the moisture and decomposes the potato, there- 
by causing a violent ebullition of gas which carries the smaller bub- 
bles present in the glass with it, and aids very materially in the 
"fining'* process. 

These latter methods can only be adopted in cases where the glass 
is melted in pots. They cannot be used in continuous tank fur- 
naces. In the latter case only such mixtures can be employed as are 
capable of freeing themselves from their enclosed bubbles without 
assistance, and the furnace must be constructed in such a manner 
that the melting batch and glass as it flows from one end of the tank 
to the other meets at each point that degree and kind of heat which 
is required for that particular stage of the melt. 

After the glass has become free from its enclosed bubbles of gas 
the temperature is allowed to drop until the glass assumes the proper 
working viscosity. This stage of the melt is called the "standing off" 
process. In the case of pot furnaces this is done by lowering the 
temperature of the entire furnace, while in the case of a continuous 
tank furnace the glass is allowed to flow to the working chamber of 
the furnace, which is always kept at the working temperature. After 
the dust and impurities have been removed from the surface of the 
glass, or "metal," as it is termed, it is ready to work. The scum 
which rests on the surface of the glass is called "gall." 

Closed pot furnaces are heated up to temperatures of 1400° to 
1500°C, or 2500° to 2730°F., while open pot furnaces are heated to 
temperatures of about 1400° to 1540°C., or 2550° to 2800°F. Con- 
tinuous tanks are worked at temperatures somewhat higher than 
those of pot furnaces as a rule, that is from 1400° to 1510°., or 2550° 
to 2750° P., the higher temperatures being the more common ones used. 
Temperatures in glass furnaces are usually measured by means of 
pyrometers, chiefly of the thermo-electric type. Such a thermo-elec- 
tric pyrometer, with platinum-rhodium couples, is capable of meas- 
uring temperature up to 1650°C., or 3000° P., within one per cent of 
accuracy. This instrument consists of a sensitive galvanometer, 
which indicates by the movements of a pointer over a carefully cali- 
brated scale the current of electricity produced by heating the junc- 
tion of a fine platinum and plantinum-rhodium or platinum-iridium 
wire, commonly termed the element. * Each instrument has to be 
standardised and the scale graduated accordingly. 


In the case of covei-ed pots the ordinary practice is to work a pot 
every other day. No definite time, however, can be given for the 
length of melting, as this varies with the size and thickness of the pot, 
the kind of glass being melted, and the temperature of the furnace. 
Open pots in the plate glass industry are usually cast once each day. 
In the case of continuous tanks the operations of charging and work- 
ing go on simultaneously at the two ends of the furnace. 

In addition to the chemical reactions which take place in the batch 
materials, the chemical influence of the furnace gases on the glass is 
a factor of vital importance. The flame of a glass furnace is in- 
variably reducing, yet the reducing effect varies ip degree, depending 
upon the condition of firing. On account of this reducing action 
certain glasses, such as lead glasses (which must be melted under oxi- 
dizing conditions to prevent the reduction of any metallic lead in the 
glass, which would blacken it), have to be prepared in closed pots 
where the furnace gases cannot come into contact with the molten 
glass. Even in the case of lime flint glasses, when as nearly color- 
less product as possible is desired, the closed pot must be employed to 
obtain the best results. 

Defects in the glass may usually be traced to impure materials, 
improper composition of the batch, improper mixing of the raw ma- 
terials, or improper firing. Difficulty is also encountered at times if 
the clay pots or tank blocks employed in the furnaces are of poor 
grade. Some of the most common and troublesome faults encountered 
are excessive amounts of glass "gall," or scum, on the surface of the 
glass, excessive foaming during the melting operation, the presence 
of bubbles, stones, cords, or striae in the finished glass, devitrification, 
and high color or low color of the glasa 

Glass gall is removed from the surface of the glass by skimming. 
Excessive gall is generally due to the undecomposed sodium sulphate 
in the glass which has either been added in the form of salt cake or 
was present in the soda ash used, or to sulphates present in some of the 
other raw materials employed. Glass gall usually rises to the sur- 
face, where it can be removed if the fining process is properly con- 
ducted. Otherwise it may remain suspended in lumps in the molten 
glass and finally separates as white blotches in the finished glass. 
One of the remedies is to use materials containing Jess sulphate. When 
sodium sulphate is used as a source of sodium it may be necessary to 
add more carbon, that the decomposition of the salt cake may go on 
more readily. Care must be taken, however, not to add any excess 
of carbon, as this is apt to produce a smoky or yellow color. Greater 
care in the "fining" operation and more thorough mixing of the 
batch may also prevent this difficulty. 

Excessive foaming is usually due to the slow heating of the batch 
in the early stages of melting. This terids to cause a separation of 


the heavier uufused material aud the lighter fused material. The 
liquified salts enclose the slowly escaping bubbles of gas and the batch 
froths or foams. This can be prevented by heating the pot to a 
higher temperature before introducing the batch, so that melting will 
proceed more quickly and the rapid evolution of gases will prevent the 
separation of the fused and unfused portions of the batch. 

The presence of bubbles in the glass produces what is known as 
**seedy" glass. This is usually due to too low a temperature or not 
allowing sufficient time during the ^^fining" process. It is very 
difficult to free a glass entirely from bubbles and in the case of some 
glasses this is impopible. 

Stones in the glass consist of undissolved portions of the batch, or 
small particles of clay from the walls of the pot or tank. Cords are 
knotty or wavy veins having a greater viscosity than the surrounding 
mass, while striae are streaks or layers of different density running 
through the glass. By avoiding impure materials, improper mixing 
and proportioning of the batch, and too slow fusion, these difficulties 
may usually be overcome. Striae may also be due to large lumps 
of cullet. The addition of too much cullet may also produce these 
difficulties. Very often stones and cords are produced by charging 
the batch into too cold a pot or furnace. Striae are especially apt to 
be developed in lead glasses on account of the tendency of the lead 
silicate to settle out, due to it« greater specific gravity. Such glasses, 
therefore, should not be allowed to stand any length of time in the 
pot before working. 

Devitrification in glass is due to the tendency of the silicates which 
compose the glass to crystallize out on cooling. Certain silicates 
have a much greater tendency to crystallize than others, and there- 
fore glasses containing them will tend to devitrify more readily. 
Devitrification rarely occurs in the pot or tank, but sometimes oc- 
curr. during the working of the glass or the annealing operation. It 
may be due to too slow chilling of the molten glass during the work- 
ing, or keeping it at the. maximum temperature of the annealing 
oven too long, and cooling it too slowly. Often it is due to an im- 
proper composition of the glass batch. 

A pink tinge in the glass is known as high color and is due to an 
excess of mangane»«;e. A green color on the other hand is known as 
low color, and is produced by an excess of iron. 




In working glass if it is allowed to cool at ordinary tc^iuperatiii'es 
hardening takes place so rapidly that a tension develops between the 
molecules of the outer and inner layers of the gl^ss. The outside 
layer naturally cools and hardens first, while the inside layers are 
still soft. Then as the inside layers cool and solidify they tend 
to contract and draw away from the outside layers, but, as the latter 
are already hard and rigid, instead of the whole mass contracting as a 
unit a tension is developed between the outer and inner layers, the 
amount of which depends upon the rapidity of the cooling. This ten- 
sion makes the glass very tough and strong and gives it the quality 
of resisting sudden changes of temperature as long as the surface 
remains unbroken. If this is scratched or cracked, however, the 
tension is relieved and the glass flies to pieces. For this reason all 
glass intended for ordinary uses has to be cooled slowly, so that the 
outside and inside layers will cool as nearly simultaneously as pos- 
sible and all tension thereby avoided. This operation is called an- 
nealing the glass. 

Some interesting investigations have been conducted by Mon. L. 
Grenet, a French engineer, to determine the limits within which an- 
nealing takes place.'* His results lead him to the conclusion that 
those limits are quite small and that there is only a comparatively 
short range of temperature where tension develops. For St. Gobain 
plate glass he found that these limits were between 943° and 1087°F., 
for a glass of composition 55% SiOj, 15.50%CaO, and 13% NagO, be- 
tween 941° and 1154°F., and for an extremely basic silicate compound 
of composition 55% SiOg, 18% CaO, 21% NaA and 6% BaO, be- 
tween 788° and 932°F. The temperatures at which these glasses 
first began to soften and lose form were ascertained to be 1440°, 
1521°, and 1350°F., respectively. If thes^ observations prove to be 
correct, the range of temperatures through which great care must be 
taken in annealing is approximately but 200°F. Above this maxi- 
mum, and below this minimum, temperature the glass may be cooled 
quite rapidly without developing tension. Grenet also observed 
that devitrification may take place below the temperature at which 
glass softens, but that in as much as the softening point was so much 
above the maximum temperature at which tension may develop, this 
should never be a source of trouble in annealing. 

There are two types of annealing kilns or ovens in use at the pres- 
ent time; namely the intermittent kiln and the continuous kiln or 

34. LlDton. The Mineral Indnatrj for 1800. Vol. 8, p. 237. 


lehr. The intermittent kiln consists of an arch and hearth on which 
the ware is laid. It is usually heated with gas, but coal or wood 
may also be used. In the case of hollow ware and flint glass kilns 
of this type of firing are so arranged that the heat is evenly dis- 
tributed over the interior while the glass is laid in. The draught 
is kept at a minimum at this stage, so that the kilns becomes filled 
with the products of combustion. When the kiln is filled, it is sealed 
and the proper Bate of cooling is accurately regulated by adjusting 
the draught with the stack damper. 

This type of kiln is still in use in many plants for annealing plate 
glass, although there is a tendency at the present time to introduce 
continuous kilns or lehrs in this branch of the glass industry.' Usually 
a separate chamber is provided for each plate of glass to be annealed. 
The slabs are laid flat on the stone bed of the kiln. This bed is 
built up of carefully dressed stone, or blocks of fire brick imbedded 
in sand, in such a way they can expand freely laterally, without caus- 
ing any tendency for the floor to buckle upwards during the heating. 
The whole chamber is heated to a temperature at which the glass 
still shows slight plasticity. The hot glass slabs from the rolling 
table are slid upon this bed and in the course of a few hours grad- 
ually settle dowif to the contour of the bed, from which they are not 
removed until quite cold. This takes anywhere from three to five 
days. Care must be taken in arranging the air passages in the walls 
and floor of the kiln in such manner that the whole kiln will cool at 
an uniform rate. 

Optical glass has to be put through a very careful final annealing 
process in cooling it, from the red heat at which it has been moulded, 
down to ordinary temperatures. The length of time occupied by 
such cooling depends very much upon the size of the object and the 
degree of refinement to which it is necessary to carry the removal 
of small internal strains in the glass. For many purposes this can 
he accomplished in from six to dght days in large kilns. In other 
cases where perfect freedom from internal strain is required much 
greater refinements are necessay and special annealing kilns whose 
tempeature can be more accurately regulated and maintained are 
oniT^loYod. In these furnaces the coolinsj can be carried on so grad- 
ually that a rate in which a fall of one degree C, occupies several 
hours can. be maintained. 

Continuous kilns, or "lehrs" have replaced intermittent kilns to 
a large extent. They are now employed for annealing much of the 
hollow ware and flint glass produced, all of the window glass and a 
considerable amount of the plate glass manufactured. This is due 
to the fact the lehr can be operated much more cheaply than the in- 
termittent kiln. The capacity of the factory is considerably in- 

Fig. 2. Enillcsa carrior for li-lirs. (II. 1.. Dixoii Cm,) 


creased for the same space occupied, and the same outlay for con- 
struction and fuel. 

A lehr consists of a long tunnel heated at the entrance to a tem- 
perature just below the softening point of the glass. The tempera- 
ture falls gradually from this point until at the other end the glass 
emerges at ordinary atmospheric temperature. In the case off lehrs 
for hollow ware the articles are stacked on trays, linked together by 
an endless band, and as each tray is filled it is pushed forward into 
the lehr, the trays thus following one another down the tunnel at a 
speed depending on the rapidity with which each trays is filled. When 
a tray has been emptied at the cool end it is returned to the charging 
end. Figure 1, Plate XLl shows a front view of three such lehrs, 
while figui*e 2 shows a slightly different type of carrier than the 
trays described above. This is an endless carrier which can be moved 
continuously or intermittently at any desired speed. This does away 
with the carrying of the trays from the back to the front of the lehr. 
When bottles are being annealed the first twenty feet of such lehrs 
are usually heated to a temperature of about 540°C., or 1,000°P. 
They are made about seventy feet long and it takes the bottles about 
three hours to pass through the lehr. 

Window glass is annealed continuously in connection with the flat- 
tening process. After the sheet of glass has been flattened it is laid 
in at one end of the lehr, which opens into the flattening oven and 
is drawn slowly to the other end. The Tondeur rod lehr is the type 
which is commonly used today. This consists of two sets of hori- 
zontal rods or bars, so attached to a series of shafts that one set may 
be raised or lowered below the other set, and slides free in a series 
of sheaves. The glass is laid upon this movable set of rods and is 
drawn for^vard the width of one sheet. The shafts are then revolved 
suflSciently to drop this set below the other set, which receives the 
glass, while the movable rods are allowed to slide back to their origi- 
nal position and raised to receive another sheet. These lehrs are 
made in sizes varying from 6^ feet wide and 44 feet long, to 8J feet 
wide and 52 feet long. 

The Tondeur rod lehr system has also been adopted for annealing 
plate glass in the case of sheets under 200 square feet in size. Lehrs 
in use for plate glass are made as long as 600 feet. The temperature 
at the heated end is usually raised to 650^C., or 1,200^P. 




Glass owes its value to the fact that it is a hard, transparent, rigid 
body at ordinary temperatures, offering great resistance to chemical 
change, which becomes plastic at high temperatures, thereby allow- 
ing itself to be moulded into any desired shape. As has already 
been stated under the fusion of glass, the last stage in the melting 
operation is the cooling of the glass to the viscosity necessary for 
working it into the shape of the various articles that are made from 
it. The procedure followed after that in manufacturing the dif- 
ferent kinds of glass goods varies somewhat for each type. Therefore, 
a brief outline of the processes employed in the manufacture of bot- 
tle glass, blown and pressed glass, rolled or plate glass, window or 
sheet glass, and optical glass is taken up here. 


Ordinary bottle glass is one of the cheapest grades of glass manu- 
factured, therefore, great economy must be exercised both in the se- 
lection of raw materials and in the methods employed in its manu- 
facture. Bottle glasses as a rule are of the lime soda type, but 
other constituents, such as iron oxide, alumina, are also invariably 
present. Fortunately color is not an item of great importance and 
a considerable range in composition is permissable, so that the purity 
of the raw materials entering into the batch does not have to come 
up to the high standards set for the better grades of glass. 

A good bottle glass must, however, come up to certain i-equirements. 
It must be sufficiently strong to resist the internal pressure to which 
it will be subjected when used for the storage of fermented or effer- 
vescent liquors, as well as the shock of ordinary use. It must re- 
main practically unattacked when called upon to contain more or 
less corrosive liquids. There are also certain requirements essential 
from the manufacturer's standpoint. These are that it shall be com- 
paratively fusible, easily worked, and readily annealed. 

Since color is not such an important item in ordinary bottles, sand 
used in their manufacture may contain a higher percentage of iron 
than those used for other types of glass, and therefore a cheaper 
grade of sand may be employed. For white bottles the iron content 
should not exceed 0.5% FeoOg, but in the case of other bottles sands 
containing anywhere from 0.5 to 7.0% FejOj are used. Iron as has 
already been stated, gives the glass a green or greenish yellow color, 
deepening to a black opacity if the quantity of iron is high. The 
lighter shades of green may be practically neutralized by adding small 

• • • • • 

■» • • < 

• • 9 « • 


quantities of manganese oxide to the glass. If the percentage of 
iron is higher, however, colors ranging from light amber to purple are 
produced hy the addition of manganese. This is sometimes done, as 
in the case of brown beer bottles. 

The raw materials commonly employed in the manufacture of bot- 
tle glass are sand, salt cake, soda ash, and limestone. A certain 
amount of manganese oxide is also usually added, and where salt 
cake is used some carbon, in the form of charcoal, coke, or anthracite 
coal must be employed. Some typical bottle glass batches have al- 
ready been given in a previous chapter. As has been stated the 
absolute chemical purity of these materials is not an item of such im- 
portance as in the case of otlier kinds of glass and, therefore, cheaper 
grades of material can be used. 

Practically all bottle glass is now produced in continuous tanks, 
as these are much more economical to operate than pot furnaces and 
give very successful results in the manufacture of this type of glass. 
Both the end port and the side port tanks are used. In the end port 
tank the gasses both enter and leave at the charging end, the flame 
being of the horse shoe type. Plate XLII illustrates such a furnace. 
The side port furnace has already been described. The working end 
is usually made semi-circular in shape. The raw materials are 
thrown in at the charging end and the molten glass flows uninterrupt- 
edly down the length of the tank to the colder, semi-circular end, 
where the working holes are situated. Fire clay rings are some- 
times kept floating in the glass at this end to retain on their outside 
the scum or **gall" carried down by the glass. The gatherer takes 
his glass from within these rings. 

Great improvements have been made in recent years in the methods 
used in manufacturing bottles. The tendency at present is to do a 
large part of the work formerly done by men by machinery, and some 
marvelous mechanical devices have been developed to accomplish 

Where bottles are still made by hand the first step is to gather the 
requisite amount of glass from the furnace. This is done by means 
of the bottle blowers pipe, which is an hollow iron rod, five to six 
feet long provided with a f^lightly enlarged end or "nose" upon which 
the glass is gathered. Several gatherings are usually necessary, 
some skill and practice being required on the blower's part to judge 
when the right weight of glass has been gathered to produce the 
bottle desired. This mass of glass is next distended slightly by the 
blower, and is then placed in a cast iron mould whose interior has 
the external shape of the bottle. This mould is made of several 
parts, usually two working on a hinge. The mould is opened by 
means of a pedal op lever to receive the glass and is then closed. By 
blowing into the pipe tlie glass is made to assume the shape of the 


mould. After this is accomplished the mould is opened and the neck 
of the bottle is broken from the rod to which it is attached* The 
shaping of the neck is done by hand by another workman. It is 
first heated up to the desired viscosity in a small furnace, or "glory 
hole/' and is then moulded into the desired shape by the aid of 
specially shaped tongs. After this has been done the bottles are 
ready to be annealed. 

Very few bottles are any longer made by the above process. At 
present machines are used in which not only the neck of the bottle is 
pressed to the desired shape, but the bottle itself is blown in a mould 
by means of compressed air. In the simplest type of these machines 
the glass is still gathered from the furnace by hand. Instead of 
using a blow pipe for this purpose, however, a light iron rod is used. 
The necessary amount of glass is gathered from the furnace by the 
gatherer and placed in a mould, which has the form of the neck with 
a space underneath, usually in the shape of a tapering cylinder, to 
hold the requisite amount of glass to finish the bottle. As soon as 
the viscous glass has been placed in the mould a plunger is brought 
down which presses the upper portion of the glass into the shape of 
the neck, while the glass underneath takes the shape of the tapering 
cylinder. This mass of glass is now called a blank. It is removed 
from the first mould by means of a ring, either by hand or mechanic- 
ally, and is placed in another mould which has the form of the fin- 
ished bottle. It is then blown to the shape of the mould by com- 
pressed air. When the bottle comes from this mould it is ready 
to be annealed. Two men are required to operate such a machine, 
a gatherer and a presser. A further improvement consists in hav- 
ing the glass flow in a thin stream from the furnace into the first 
mould, the stream being cut off automatically by a knife each time 
sufficient glass has flowed into the mould. The rate at which the 
glass flows out can be regulated by enlarging or decreasing the size 
of the opening through which it flows. This done away with the 
hand gathering. In order to have this process go on continuously 
duplicate mould have to be provided with each machine, so that as 
one is withdrawn another takes its place. These machines are of 
the semi-automatic type and require only one man to operate them. 
In addition one boy is usually employed to each machine to take 
away the finished bottles. Plate XLIII illustrates machines of the 
type above described, in which both the pressing of the neck and the 
blowing of the bottle itself are done mechanically. 

The greatest invention in the bottle industry in recent years has 
been a still better type of machine than the ones thus far described, 
one which operates entirely automatically. . This is known as the 
Owens automatic gathering and blowing machine, from the name of 
its inventor. It is shown in Plate XLIV. This machine takes the 

I'LATE XLlll. 

Fig. 3. I'ri'wiiig and blowing maHiiiu- for niilk j moult wore. (U. L. Dixon Co.) 


c] hlnwiiiK mnrhinc. 


molten glass from the furnace, shapes the neck and the bottle itself, 
and turns out a finished product ready for the annealing lehrs, the 
whole operation I'equiring practically no attention and going on con- 

The Owens bottle machine takes the glass from the furnace by dip- 
ping a preliminary form into the molten glass, mouth down, and ex- 
hausting the air, so that the glass rises in the form. To make the 
process continuous a number of forms are attached to a revolving de- 
vice, the rotation of which brings each of these in its turn to the fill- 
ing station. This brings in the difficulty that each form is brought 
to the same point to be filled. But the first form plunged into the 
molten glass cools it sufficient at this point to make it unfit for use 
for the next form. To overcome this difficulty a furnace with revolv- 
ing fore-hearth is used. 

This fore-hearth consists of a rectangular brick chamber adjoining 
the tank furnace proper and covering a fan shaped hearth, into which 
the forms of the machine dip. This pan has a depth of about ten 
inches, and a diameter of 6| to 8 feet. It is covered by the brick 
chamber except where a small strip of the glass surface is exposed by 
the rounding out of the wall of the covering chamber. The machine 
is brought up as close as possible to this wall, so that the forms pass 
over the exposed surface of the glass in their revolution and through 
the sinking of the machine dip into it. The space above the circular 
hearth, which has a height of about six feet, is heated by means of 
burners which can be regulated so as to keep the glass at an uniform 
temperature. The glass flows from the melting tank proper through 
a clay trough, with the smallest possible fall, in a slow continuous 
stream to the circular hearth. 

The space underneath this hearth is left open to allow the better 
cooling of the iron structure underneath. This consists of a platform 
built of iron supports upon which the bottom of the hearth rests. 
These supports rest upon croas pieces, with set screws which allow 
the hearth to be leveled. The cross pieces are supported upon a 
vertical shaft which rests on a bed of conical rollers on the floor of 
the plant. The pan is caused to slowly revolve by means of a worm 
gear attached to this shaft, which is made sufficiently long that the 
driving gear is kept away from the heat of the furnace. 

The4iearth makes about two and one-half revolutions per minute, 
so that every form is dipped into a new place where the glass has not 
been chilled. The cooled places, and the glass strings falling back 
at the cutting ofif of the glass mass from the mould, are again warmed 
dnrirg the revolution of the pan before another mould strikes this 
pfirticular spot. Tnnsjmuch as the pan and the machine revolve in 
opposite directions, at the place of dipping the form and the pan 
travel in the same direction at approximately the same speed. Di- 



rectly after the form has been dipped into the glass it begins to fill 
by suction. At the end of the filling the glass is cut off by a knife 
which passes underneath the form^ and the form is raised and again 
passes over the edge of the hearth. 

The first step in the operation of making a bottle is the dipping of 
the preliminary form, which is placed underneath the head piece, into 
the molten glass. The head piece has a mouth stem projecting into it 
to which a suction pipe is attached. The glass rises up into the pre- 
liminary form and head piece and around the stem and is automatic- 
ally cut off by a knife. Then the form is raised and passes beyond 
the hearth, the preleminary form separates, leaving the viscous glass 
hanging free from the head piece, and the final form rises with open 
halves from below and closes around it. The mouth stem is next 
withdrawn from the head piece and the bottom form is brought into 
place. The blowing head is now brought over the head piece and 
the bottle is blown into shape. The final form and head piece then 
open and the finished bottle rests free on the bottom form, from which 
it is thrown into a conveyor trough. Just before the final mould 
and head piece open the mouth stem sinks a little into the mouth of 
the bottle so that the bottle, in case it should cling anywhere to the 
mould, will not fall over. 

The whole operation is carried on automatically. The machine 
itself rests on a truck which can be moved on a track to and from 
the furnace by its own power. Six or ten sets of forms are arranged 
symmetrically around a central vertical shaft and are through rota- 
tion of this axis brought in turn over the revolving hearth. After 
the preleminary form has been brought over the hearth it must be 
dipped into the glass. To accomplish this the whole revolving por- 
tion of the machine is lowered. This is done by having it rest in a 
lowering and raising device, which works automatically. The moulds 
are kept cool by means of a blast of air from the outside. The inside 
of the moulds are treated with lubricating oil from time to time. 
With the larger Owen's machines, wliich have ten moulds, from 24 to 
25 bottles of ordinary size may be turned out in a minute. 

Tn the annealing of bottles the continuous kilns or lehrs have en- 
tirely replaced the old stjle intermittent kilns. Such lehrs are built 
about 70 feet long and have the first 20 feet heated to a temperature 
in the neighborhood of 1,000°F., which then gradually drops to that 
of the atmosphere. The lehrs are run at such a speed that it takes 
about three hours for the bottles to pass through the lehr. 


In the manufacture of hollow glass vessels, such as are used for 
table ware, lamp chimneys, etc., the process of manufacture are very 
much similar to those used in the production of bottles, the principal 


difference between bottles and the better grades of hollow glassware 
lying in the composition and quality of the glass used. There are 
two types of glass used in the tnanufacture of tliis kind of glassware, 
namely, lime-alicali-silicate and lead-alkali-silicate. Soda is the alkali 
usually employed in the tirst glass on account of its cheapness. Such 
glass is often spoken of as lime flint. In the case of Bohemian ^'Crys- 
tal/' however, potash is substituted for the soda.. In the lead alkali 
silicate glass, potash is the alkali commonly employed on account of 
the added brilliancy which it imparts to the glass. Tliis type of 
glass is usually spoken of as lead flint. The lime flint glasses are 
made from sand, soda ash or salt cake, and limestone or burnt lime. 
When salt cake is used some carbon has to be added. A little man- 
ganese oilde also is used as a rule to counteract the coloring efl'ects 
of the small amount of iron present in the sand and other raw ma- 
terials used. The lead flint glasses are made from sand, potassium 
carbonate and ired lead. Besides these principal constituents, some 
oxidizing agent, such as nitre, and a decolorizer, such as manganese 
dioxide, are also added to the batch in most cases. Typical batches 
for lime and lead flint glasses have already been given in a previous 

In the better grades of blown and pressed glassware it is important 
that the raw materials used be as pure as possible with respect to 
harmful constituents, such as iron oxide. Sands used for this grade 
of glass, therefore, should not contain over 0.02% ferric oxide. In 
the manufacture of lead flint glass closed pot furnaces must be em- 
ployed. For the better grades of lime flint ware these are also used 
because a glass of better color can be made in such a furnace than 
can be produced in a tank furnace. For the poorer grades, however, 
continuous tank furnaces are frequently used at the present time. 

Formerly all hollow glassware was produced by hand. By intro- 
ducing moulds in which the articles can be blown to the desired shape 
a part of this hand work has been eliminated. A still later improve- 
ment has been the development of machines, very similar to those 
used in the bottle industry, for blowing the articles into the desired 
shape by means of compressed air. All of these methods are in use 
at the present time, although the most primitive of these, in which 
hand work is employed entirely, is used only in special cases where 
but a comparatively small number of articles of a particular shape 
are desired, so that it would not pay to make a special mould for 

In shaping glass articles by hand the glass blower requires a bench 
provided with two projecting side rails or arms, across which the 
blow pipe may be laii in such a position that it can be kept in gentle 
rotation by rolling it backward and forward. An ordinary blowerV 


pipe, similar to the one used in making bottles, and a rod to which 
the glass article upon which work is being done can be attached by 
means of a little viscous glass taken ft'om the furnace, are employed, 
as well as a number of ditlerent sized and shaped shears and pincers 
for cutting off, pressing in, and distending the glasa A flat board 
and a stone or metal plate upon which the glass can be moulded com- 
plete the equipment. 

The first step in the production of such an article as a tumbler 
consists in gathering the proper amount of glass on the pipe and blow- 
ing it into a small bulb, which is then blown to the proper size and 
elongnated by gentle swinging the pipe. Then the lower end of this 
elongnated bulb is flattened by gentle pressing it on the flat plate 
provided for the. purpose. The lower portion of the bulb now has 
the shape of the finished glass but remains attached to the blow pipe 
by means of a shoulder and neck. In the hand process the tumbler 
is next separated from the pipe at the point which leave it of the 
correct length. An iron rod is then attached to the bottom by means 
of a little molten glass and the broken edge of the tumbler is held in 
a flame to round it. The brim of the glass can then be widened or 
otherwise shaped by rotating it or pressing it in or out by means of a 
piece of wood. Plate XLV illustrates the various steps necessary 
in the production of such a tumbler. 

Iron moulds are now used almost exclusively in the blowing of such 
tumblers. These facilitate the operation very much. The glass is 
gathered on a hollow pipe, blown into a bulb, and after shaping by 
rolling on a polished plate or by revolving in a hollow iron or wooden 
block, is blown into the mould and takes its shape. In the case of 
lamp chimneys, tumblers, and other cylindrical articles, the glass is 
revolved in the moulds and shows no joint or mould marks. Such 
moulds are lined with charcoal or special paste which enables the 
glass to be turned. In the case of lantern globes, or articles with 
raised or sunken patterns, the glass is blown without turning and 
takes the exact impression of the mould. Figure 1, Plate XLV [ illus- 
trates the blowing and moulding of lantern globes. 

The final process in the manufacture of a tumbler after it comes 
from the mould consists in breaking it from the pipe, well above the 
shoulder, and annealing it. It then goes to the trimming room where 
it is cut off at the desired point, either by being heated locally and 
suddenly by a specially shaped flat blow pipe flame, or by an elec- 
trically heated wire. The rough edge is then rounded off, either by 
the aid of a blow pipe flame or by slightly grinding and polishing the 
edges. In the case of such articles as lamp chimneys the bottom 
must also be cut off. A. lamp chimney and tumbler are sometimes 
blown together, the lower portion constituting the tumbler while the 
upper portion constitutes the lamp chimney. 












FiE 3. Hanil proRH. 


At the present day almost all hollow glassware is blown in moulds. 
Compressed air has to a great extent replaced the blowers pipe. In 
the finishing of certain articles pressing in conjunction with blowing 
is resorted to, as in the case of the bottle industry, and similar ma- 
chines are employed. 

Many glass articles, such as saucers and heavy tumblers, are made 
by pressing alone. The glass is gathered on the end of an iron rod, 
by revolving it rapidly in the molten glass. It is then carried to the 
presser who cuts off with a pair of shears the amount desired and 
allows it to drop into the mould. A metal plunger is then lowered 
into the mould and the glass is forced to fill the space between the 
plunger and the mould. When the glass has become firm the plunger 
is withdrawn, the mould is opened, and the article is either sent direct 
to the annealing lehr or is first reheated in an auxiliary furnace or 
glory-hole to remove mould marks or to alter its shape. 

Press moulds are made of cast iron and are constructed in such a 
manner that the article can be readily removed. The mould and 
plunger are kept cool by streams of air blown against them. The 
plunger is usually operated by hand power, but for some purpose 
i^team or compressed air is used. Figure 2, Plate XLVI shows a 
press in operation, while Figure 3 illustrates the construction of 
such a press. The moulds are not shown. 

Almost all blown and pressed glassware at the present day is an- 
nealed in continuous kilns or lehins. Where the glassware is to be 
cut and polished afterwards, as in the case of many articles made 
from lead flint, after it comes from the lehr it is put through a second 
annealing operation in intermittent kilns of the type already de- 
scribed. This is necessary because it is essential that all internal 
strain be removed before the glass undergoes the cutting and polish- 
ing operation, or it will crack and fly to pieces. 

Cut glassware is made from lead flint glass on account of its soft- 
ness and brilliant lustre. The articles are first given their shape by 
any one of the processes described above. Often all or part of the 
raised or sunken patterns on the glass are produced in the moulds. 
It is then only necessary to go over these lightly in cutting and then 
to polish them to bring out the brilliant lustre of the glass. In other 
cases, * ho wever, the patterns are cut into the glass entirely, after it 
has been shaped and annealed. When the articles come from the 
moulds before they are cut they are known as blanks. 

The design is first cut into the glass of the blank by pressing it 
against an iron wheel fed with sand. The rough surface thus pro- 
duced is then smoothed on similar wheels dressed with a finer 
abrasive, and is finally polished by a felt covered wooden bobbin 
dressed with French "rouge" or putty paste. ^ 

In etching or embossing hollow ware hydrofluoric acid is employeil. 


The portions of the glass to remain^ unacted upon are covered with a 
"resist," composed generally of a solution of bitumen and beeswax in 
turpentine, either by first coating the whole article and then scratch- 
ing out the portions to be etched, or by applying the "resist" wilJi a 
brush, or by means of a transfer. The article is then immersed in 
the acid for a short time, washed, and cleaned. If a weak solution of 
hydrofluoric acid is used the etched portion is clean and transparent, 
but if a bath of acid sodium fluoride is used a matte surface is pro- 


Window glass is made from sand, limestone, salt cake, and a few 
accessory substances, such as carbon in the form of anthracite coal, 
or coke, and manganese oxide. Occasionally some soda ash is used 
to replace part of the salt cake. For window glass the sand employed 
should not contain more than 0.5% FCgOs. In practice the sand is 
not always dried, but where wet sand is used determinations of the 
moisture contents are made from time to time, and allowance is made 
for this in the preparation of th^batch. But even where such de- 
terminations are made, in as much as the moisture content is apt 
to vary considerably even in different parts of the same shipment of 
sand, (which could only be checked by a large number of determina- 
tions), variations in the composition of the batch result which are 
only permissable in the manufacture of a cheap grade of glass, such 
as window glass. For the better grades of glass the sand is always 
dried before using. v 

Window glass is now prepared almost entirely in continuous tank 
furnaces of the regenerative type. Tanks up to 113 feet long, 27 
feet wide, and 5 feet deep, holding 1,400 tons of molten glass are in 

Until comparatively recently all window glass was hand made, but 
now machines have been developed which are gradually replacing the 
hand labor. In the old hand process the blowers pipe consists of an iron 
tube, about 4^ feet long, provided at one end with a wooden sleeve or 
handle and a mouth piece, while the other end is thickened into a sub- 
stantial cone with a round end. The nose of the pipe is first heated 
up to the temperature of the molten glass and is then dipped, into 
the glass and turned slightly, once or twice, for the first gathering. 
This is allowed to cool until it has become fairly stiff, the whole pipe 
being meanwhile rotated so as to keep the gathering nicely rounded. 
A small hollow space is formed in the mass of glass through a slight 
application of air pressure by blowing. As soon as the first gathering 
has become sufficiently viscous a second one is taken, care being taken 
that no inclusions of air bubbles result between it and the first one. 
This is done by gradually rotating the pipe as it is lowered into the 


After Ro.senhQiri. 
S««tionaI iliugnim sliuwinK cvolutiuii of n cyliiiilrr nf wiiiilon' ftlnss. 


[''is. 3. Cracking open the cylinders. 


molten glass. Three, four to five gatherings are sometimes necessary 
to obtain sufficient glass on the end of the pipe. 

After the last gathering has been taken up and the mass has cooled 
to a working viscosity, the gla>$s forms an approximately spherical 
shaped mass, with the nose end of the pipe near its center. The next 
step is to bring the bulk of the glass beyond the end of the pipe and 
then to form, just beyond the end of the pipe, a widened shoulder of 
thinner and, therefore, colder glass of the diameter required for the 
cylinder into which the glass is to be blown. This is done by the aid of 
specially shaped blocks and other instruments in which the glass is 
turned and blown. The final shape attained at this stage is that of 
a squat cylinder which has the bulk of the glass at its lower end. 
Plate XLVII illustrates the various shapes through which the mass 
of glass passes during this operation. 

The next step is to blow this mass into a cylinder of equal thick- 
ness throughout. The thick lower end of the cylinder is first held 
in a heating furnace until the glass become of the proper viscosity, 
and then the pipe is swung with a pendulum movement in the blower's 
pit. The cylinder thus becomes elongnated under its own weight 
and any tendency to collapse is counteracted by the application of 
air pressure from the mouth. A rotary motion is also given to the 
pipe from time to time. The reheating of the lower portion of the 
cylinder is repeated several times until the cylinder has reached an 
equal thickness throughout. Then the rounded end is opened. The 
lower end is heated until it becomes very soft. The cylinder is with- 
drawn from the furnace, held in a vertical downward position in the 
blower's pit, and spun very rapidly about its longitudunal axis. The 
glass is thus caused to open out under the centrifugal action and by 
increasing the speed of rotation eventually is brought to form a true 
continuation of the rest of the cylinder. It is then allowed to solidify. 
Plate XLVIII shows several views in a window glass factory where 
the hand process is employed. 

The completed cylinder is next placed upon a wooden rack and the 
pipe is severed from the cylinder. After the cylinder has cooled, the 
neck and shoulder are removed by passing a wire heated by electricity 
around the cylinder at the point where it is to be cut off, and then 
applying a cold or moist iron along this heated portion. As a rule 
a crack immediately runs com[>letely around the cylinder along the 
line occupied by the wire. The neck and shoulder of the cylinder 
are thus removed and the cylinder is ready to be split. This is done 
on a special stand upon which it is laid in a horizontal position. The 
splitting is done by drawing a heavy diamond skillfully down the 
length of the cylinder on the inside. A hot iron, followed by moist- 
ening, is sometimes used for the same purpose. 


After the cylinder has been split it is ready to be flattened and 
annealed. For this pui^pose the cylinder is first taken to a special 
kiln, or flattening oven, where they are heated to a dull red heat. 
They are then lifted, one at a time, onto a smooth fire clay tile and 
flattened and polished with a wooden block on the end of a long 
handle. From there the flattened sheets go to a continuous anneal- 
ing kiln or lehr, which has already been described in the chapter on 
annealing. The flattening ovens and lehrs are usually built to- 
, gether. The split cylinders are placed into a short, tunnel shaped, 
heated kiln, through which they are slowly conveyed to a large re- 
volving circular table, carrying four flattening tiles, one in each quad- 
rant. -In the kiln they are heated up to the necessary temperature 
for flattening. The cylinder then drops onto a tile on the flatten- 
ing table, is carried to the front of the furnace where a inan flat- 
tens it through a large opening by means of a wooden block attached 
to a long handle and it then continues around to the lehr, where an- 
other man through a second opening, lifts it onto the rods of the lehr 
conveyor. After the glass comes from the annealing lehr the sheets 
are examined for defects, sorted, cut and trimmed to the desired 
shape, and packed for shipment. 

"Ground glass" is prepared by abraiding the surface of the glass 
by impinging a stream of fine sand upon it by means of a powerful 
air blast. This renders the surface of the glass rough and opaque. 
Any desired design may be produced upon it by protecting portions 
of the surface by means of metal stencil plates. When glass is to 
be frosted it is first sand blasted and then coated with a hot solu- 
tion of hard glue, several coats being applied. It is then placed in a 
warm chamber, where the force exerted by the contraction of the 
glue on drying tears away the surface of the glass in a peculiar man- 
ner, giving it the appearance of a frosted window pane. 

What the Owen's bottle machine has done for the bottle industry, 
the Lubber's cylinder drawing machine has accomplished for the win- 
dow glass industry. Machine made window glass has through the 
advent of this machine largely replaced the hand made glass. In 
using this machine the glass is first ladled from the furnace into a 
flat, shallow clay pot. These pot are made double, so that while 
one is full of glass the other one is in an inverted position underneath, 
thus allowing the glass adhering to the sides to flow out under the 
heat of burners placed beneath it for this purpose. The glass cylin- 
ders are drawn from these pots. A large blow pipe is immersed into 
the molten glass, compressed air is introduced, and the blow pipe is 
gradually withdrawn from the molten glass. By carefully regulat- 
ing the speed of the withdrawal and the amount of air introduced 
cylinders of uniform diameter and thickness of glass can be made. 

The factors which determine the diameter of the cylinder and thick- 


hese of the glass are the pressure of the surrounding air, the rapidity 
with which the cylinder is withdrawn, and the temperature of the 
glass. It is necessary to have the pressure inside of the cylinders 
a little higher than the surrounding air, or a cylindrical shape will 
not be maintained. As the air gradually cools in the cylinder more 
air must be admitted. Air must also be admitted to occupy the new 
space inside the gradually enlarging cylinder. For these reasons 
there must be a slow increase in the rate of admitting the air. This 
is controlled automatically. The speed of withdrawal of the cylin- 
der has to be gradually increased also, on account of the slow cool- 
ing of the glass. This is done by having a pulley with a conical or 
tapering face, thus making its diameter increase as the operation 
proceeds, upon which the cable which raises the blow pipe and cylin- 
der is wound. The temperature of the glass has an important bear- 
ing on the thickness, the glass becoming thicker as the temperature 
becomes cooler. Cylinders 20 to 24 feet long and 30 inches in 
diameter can be made with these machines. The trimming, splitting, 
flattening and annealing are conducted in a manner similar to that 
used in the hand process. 

Other types of window glass machine have been developed, though 
hardly beyond the experimental stage, in which continuous sheets of 
glass are drawn from the tumace. Plate XLIX shows the outer ap- 
pearance of a glass drawing machine of this type. 


Ordinarily when the term plate glass is mentioned, polished plate 
is referred to, but there is another type known as rough "rolled plate," 
. used for skylights, etc., that is also made by being rolled out into a 
sheet on a metal plate. Rough rolled plate is a cheap type of glass 
and is only used where appearance is not considered an impoptant 
factor, the chief requirement being cheapness. The color is only of 
importance in so far as it affects the quantity and character of the 
light which it admits to the building. Sand, salt cake, and limestone 
are the chief raw materials used, together with the addition of carbon 
in the form of anthracite coal, coke or charcoal, and usually some 
clarifying and decoloring agents. Sands similar to those used for 
window glass may be employed for rough rolled plate. 

Continuous tank furnaces are employed to melt the glass. Since 
the cheapest glass batches to prepare are those poor in alkalies and 
high in lime this type of glass has comparatively high melting point, 
and the furnaces must be constructed so as to be able to work at high 
temperatures. Otherwise the construction of the furnace is very 
simple, as no requirements for regulating the temperature of the vari- 
ous parts in order to insure perfect fining of the glass are required, 
because absolute freedom from enclosed gas bubbles is not necessary 


The furnace, therefore, generally consists simply of a rectangular 
taDk, into one end of which the raw materials are fed, while the glass 
is withdrawn by means of iron ladles from one or two suitable open- 
ings at the other end. The size of the ladle used depends on the size 
of the sheet to be cast, the object being to have just the amount of 
glass for the sheet to be rolled. Sometimes ladles carrying as much 
as two hundred pounds of glass are used for large sheets. They are 
suspended from slings that run on an overhead rail. 

The rolling table used in the manufacture of rolled plates consists 
essentially of a cast iron slab of the proper size to accommodate the 
largest sheet to be rolled. A massive iron roller is moved over thii 
slab, driven either by hand or mechanical power, usually the latter. 
The thickness of the sheet to be rolled is regulated by means of strips 
of iron placed at the sides of the table, in such a way as to prevent 
the roller from descending any further towai'ds the surface of the 
table. So long as the glass is thicker than these strips the entire 
weight of the roller rests on the glass and presses it down until the 
requisite thickness is attained and the weight of the roller is taken 
by the iron strips. The width of the glass is regulated by means of 
a pair of guides, formed to fit the forward face of the roller and the 
surface of the table. The roller pushes these guides ahead of it and 
the glass is confined between them. When the sheet of glass has 
be«n rolled out it is left on the table until it has cooled and hardened 
sufficiently to be safely moved, Plate L shows two types of casting 

The sheet is next moved to the annealing kiln or lehr by being 
drawn onto a stone slab and pushed into the mouth of the kiln. This 
kiln consists essentially of a long, low tunnel, heated at one end and 
cool at the other, the temperature decreasing gradually and uniformly 
between the hot and cold ends. The sheets slowly pass down this 
tunnel and are gradually cooled and annealed. They are moved down 
the tunnel by a series of rods similar to the Tondeur rod system used 
in window glass annealing lehrs. Ordinarily the. sheets lie flat on 
the floor of the kiln tunnel. Their movement is effected by a system 
of moving grids which run longitudinally down the tunnel and can 
be lowered into recesses cut in the floor for them. At regular inter- 
vals the iron grid bars are raised sufficiently to just lift the sheets 
from the bed of the kiln, and are then moved longitudunally down 
the kiln a short distance, carrying the sheets forward with them, and 
again depositing them on the floor of the kiln. The grids return to 
their former position while lowered into their recesses below the 
level of the kiln bed. 

After coming from the annealing lehr the sheets of rolled plate 
glass are taken to the cutting and sorting rooms where they are classi- 

^ and trimmed to the. desired shape and size ready for the market. 

Fig. 1. Casting tablo. (H. L. Dixc 

i glass grimling and poliHhing plant. 


Polished plate glass requires much greater care in the selection of 
raw materials than does either window glass or rough rolled plate. 
Color is an item of considerable importance on account of the greater 
thickness of the plate glass as compared with window glass, which 
makes slight shades of color much more pronounced than in the thin- 
ner glass. It is made from sand, limestone, and salt cake, together 
with some soda ash. Carbon in the form of coke or coal has to be 
added to the batch to help reduce the salt cake, and some clarifying 
and decoloring agents are also as a rule employed. Batches for plate 
glass have already been given in a previous chapter. The sand used 
for ordinary plate glass should not contain more than 0.2% Fe^Oa 
and where it is used in making mirrors not more than 0.1%. 

The glass is melted in large open pots, varying in diameter from 
38 to 52 inches. The larger ones weigh up to 2,400 pounds and hold 
2800 pounds of molten glass. Twenty pots are usually placed in a 
furnace, ten on a side, as has already been described.^ The furnaces 
are heated up to temperatures of about 2800°F. Care is required to 
insure perfect melting and fining, since even minute defects are 
readily visible in plate glass, and detract seriously from its value. 
The pots usually have to be filled three times with batch before they 
contain a sufficient charge of glass. About twenty-four hours are 
required to melt and fine the glass in each pot. 

When the glass in a^pot is ready to be cast the furnace door in 
front of the pot is raised and the pot is withdrawn from the furnace 
and carried by means of an overhead crane to the casting table. To 
facilitate this operation the pots are provided with projections on 
their outer surface by which they can be held in suitable shaped 
tongs or cradles. Before the pot is poured it has to be carefully 
skimmed to remove the glass "gall" which collects on top of the molten 
glass. When the pot has been brought into position over the rolling 
table, it is tilted and the glass is poured out in a steady stream upon 
the table, care being taken to avoid the inclusion of air bubbles during 
this operation. As soon as the pot is empty it is returned to the fur- 
nace as rapidly as possible to avoid excessive cooling. 

The casting table consists of a large, massive, flat table of iron, 
having as an attachment a he^vy iron roller which has a length equal 
to the full width of the table. The sides of the table are fitted with 
adjustable strips which permit the producing of plates of diflferent 
thicknesses. As the half fluid glass is poured onto the table from the 
melting pot, the roller quickly passes over it and rolls it out into a 
sheet of uniform thickness. The heavy roller is then moved out of 
the way and by means of a stowing tool the red hot plate is shoved 
into an annealing oven. Figure 1, Plate LT shows the method of cast- 
ing a plate of glass. 


At the present time there is a tendency to introduce continuous 
kilns or lehrs for annealing plate glass, although many plants stiH 
use the intermittent type of kiln. The difficulties with the continu- 
ous lehrs have been to devise mechanical means to handle sheets of 
glass as large as those frequently rolled in the plate glass industry 
in such a manner as to prevent them from warping, and to design such 
type of lehr that the temperature would drop sufficiently uniformly 
from one end to the other to insure perfect annealing of the glass, 
so that the plates would be able to stand the rough usage of grinding, 
polishing, etc., to which they are later subjected. These difficulties 
have now been practically overcome so that continuous lehrs are 
used in some factories. A modification of the Tondeur rod lehr sys- 
tem has been adopted for handling plate glass in continuous kilns 
which work admirably for plate up to two hundred square feet in 
size. Intermittent kilns for plate glass have already been discussed 
in the chapter'on annealing. One kiln is usually provided for each 
casting table, so that the glass may be shoved from the table directly 
into the kiln, the floor of the latter being on the same level as the top 
of the table. The plates remain in these kilns for several days, while 
the temperature gradually drops to that of the atmosphere. 

When the plate comes from the annealing oven it has a rough, 
opaque, almost undulating appearance on the surface, although the 
inside is perfectly clear. It is first inspected carefully so that bub- 
bles or other defects may be marked for cutting out. It then goes 
to the cutter who takes off the rough edges and squares it into the 
right dimensions. After this has been done it is ready for the grind- 
ing rooms. 

The process of grinding and polishing plate glass consists essen- 
tially of three steps. First, the surface of the glass is ground so as to 
make it as perfectly flat as possible. A coarse abrasive is used for 
this purpose which leaves the glass with a rough, gray, surface. The 
second step consists in grinding this rough, gray surface by means 
of a finer abrasive until it becomes as smooth as possible. The gray 
surface is still retained. This is removed in the final process of 
polishing with rouge, by means of which a brilliant, clean surface 
is produced. 

The grinding is done on large, flat, revolving platforms or tables 
made of iron, and usually twenty-five or more feet in diameter. The 
grinding table is prepared by being flooded with plaster of Paris and 
water. The glass plates are carefully fitted and lowered upon this 
surface and tramped into place until the plaster has set. AfJ^&r this 
greater security is obtained by pegging them with wooden pins, and 
then the table is set in motion. The grinding is done by revolving 
runners. The runners consist of iron slabs or wooden boxes shod 
with iron, but much smaller in diameter than the grinding table. 


These runners also rotate about a central vertical axis, being set in 
motion either by the frictional drive of the revolving table under 
them, or by the action of an independent driving mechanism. 

Sharp sand is HxBt fed upon the table and a stream of water con- 
stantly flows over it. An attempt is usually made to roughly clas- 
sify the sand, the coarser being first fed an? then finer and finer. 
The final grinding is done by means of emery. Pigure 2, Plate LI 
shows a view taken in the grinding room of a plate glass factory. 
After one side of the plate has been ground down to a smooth, gray 
surface, the plates are taken up, turned over, and the other side is 
ground in a similar manner. After the plates have two smooth, par- 
allel, gray surfaces, they are ready to be polished. This is usually 
done on another special table. Rouge, a variety of finely pulverized 
iron oxide, applied with water is the polishing medium used. The 
rubbing is done by blocks covered with felt. Reciprocating ma- 
chinery is so arranged that every part of the plate is brought un- 
derneath the rubbing surface. After the glass has been polished it 
is sorted, classified into seyeral^rades, and cut to the desired sizes, 
ready for shjppiagr"' " 

^,„^Jffrr€'fisL8B is rolled plate glass in which during the rolling process 
wire has been imbedded, which adds to its strength and prevent it 
from flying to pieces when cracked. It is used to considerable extent 
in fire proof construction for this reason. This type of glass is 
usually made by rolling a sheet half the thickness of the final sheet, 
placing the wire mesh on this and then rolling another layer of glass 
on top of it. Two difficulties are encountered in the manufacture of 
wire glass. The most serious one of these is the difference in thermal 
expansion of the glass and the wire. As glass and wife cool down 
from the heated condition, the wire contracts considerably more than 
the glass, and breakage results either immediately, or the glass is 
left in a condition of severe strain and is apt to crack spontaneously 
afterwards. The second difficulty lies in the fact that most metals 
when heated give off considerable quantities of gas, and when this 
gas is evolved after the wire has been imbedded in the glass, numer- 
ous bubbles are formed which not only render the glass unsightly 
but also lessen the adhesion between the wire and the glass. This 
difficulty can usually be overcome by keeping the wire clean and ex- 
pelling all gas from it by preliminary heating. 


^ In the production of optical glasses the kinds and relative propor- 
tions-of -the raw materials-«sed- depends upon the chemical compo- 
sition of the particular glass desired. A glass of such chemical com- 
position is produced as has been shown by previous experiments to 
possess the optical properties desired. Extreme care has to be exer- 




cised so that only such raw materials are used 4is possess the greatest 
possible chemical purity and these must be thoroughly mixed, since 
optical glass must be absolutely homogeneous. In order to make 
this mixing more nearly perfect the raw materials are usually em- 
ployed in a more finely ilivided state than in the case of the ordinary 
varieties of glass. A little **cullet" or broken glass from previous 
meltings is usually added to the batch. This must have the same 
chemical composition as the glass which is being produced. 

Optical glass is made in covered pots. The pot furnaces differ 
from the ordinary type in that each furnace holds but one pot, so 
that the time and temperature of the melting operation can be care- 
fully regulated for each individual fusion, this extreme care being 
necessary in the manufacture of optical glasses. In addition to the 
I>ot furnaces kilns are also required for the preliminary heating and 
the final cooling of the pots. The pots employed for this purpose 
have thinner walls than those used for flint glass and the fire clay 
from which they are made has to be. even more carefully selected, so 
there will be no contamination of the glass by iron or other impuri- 
ties from the walls of the pot. 

The covered pot is first carefully dried, as in the case of flint 
glass pots. It is then placed in one of the preliminary heating kilns 
and the temperature is gradually raised over a period of four or five 
days to a red heat. In the mean time the pot furnace has also been 
brought up to about the same temperature. The pot is transferred 
to it as rapidly as possible, so as to reduce the amount of cooling to a 
minimum. The melting furnace is then sealed up by a temporary 
brickwork, leaving only the mouth of the pot's hood accessible. It 
is heated five or six hours longer until the melting temperature of 
the glass is reached. Then pieces of cullet, from previous meltings 
of the same chemical composition, are charged into the pot and the 
bottom and sides of the pot are glazed with this glass by means of 
a large iron ladle. This is done to prevent the raw materials at- 
tacking the walls of the pot during the early stages of the melting 

As soon as the pot has been thus glazed it is ready to receive the 
first charge of batch. The raw materials are introduced a little at 
a time, a fresh layer being added as soon as the previous one has 
melted. This is kept up until the pot contains the requisite amount 
of molten glass. The charge cannot all be introduced at once, be- 
cause it occupies more space than the resulting glass, and also be- 
cause it froths considerably during the early stages of melting. If 
too much material is added in one charge an overflow of half melted 
glass is apt to occur through the mouth of the pot. 

As soon as the batch has all been thoroughly fused, the glass is 
ready for the "fining" process. To accomplish this the temperature 


of the furnace is raised. This allows the glass to become more fluid 
and also causes the bubbles of gas to expand, both of which facilitate 
their escape. This temperature is maintained until the glass is en- 
tirely free from bubbles, which takes anywhere from six to eight, and 
in some cases even thirty hours. Great care and considerable ex- 
perience are required during the "fining" to maintain the right tem- 
perature. If it is too low the bubbles will not rise, while if it is 
raised too high the glass may attack" the pot and dissolve some of 
the clay. 

When the "fining" operation has been completed the tempemture 
is allowed to drop somewhat and all scum which has collected on the 
surface of the glass is carefully removed. The glass is now ready 
for the stirring operation, which is necessary to render it perfectly 
homogenous and free from striae. A stirrer consists of a hollow 
fire clay cj'linder, 4 to 4J inches in diameter, provided with a deep 
square hole at the upper end, into which a small iron bar passes. This 
clay cylinder is first raised to a red heat and is then dipped into the 
molten glass by means of the iron bar. It is left in this position for 
an hour or so to allow the bubbles forming on it to escape to the sur- 
face. The stirring consists in holding the cylinder in a vertical po- 
sition and giving it a rotary motion by means of the bar attached to 
its upper end. From four to twenty hours are required for this 
operation. The stirrer is then removed. By this time the glass 
has become sufficiently cooled that the stirrer can only be moved in 
it with difficulty. The pot is next lifted out of the furnace and 
placed on a fire brick platform where it is allowed to cool freely for 
half to three quarters of an hour. This causes it to solidify com- 
paratively rapidly and prevents any aggregation of heavier and lighter 
parts to occur. 

When the glass has been chilled down to a certain point, however, 
this rapidity of cooling must be arrested, or the whole contents of 
the pot will crack and splinter into minute fragments. It is, there- 
fore, taken to the annealing furnace, where during the next three 
days, or so, the mass is allowed to cool down slowly to ordinary tem- 
peratures. As soon as this has taken place the pot is drawn out 
and the fire clay shell, which is generally found cracked into many 
pieces, is broken away from the glass, which ^ usually found to be 
more or less fissured, a number of large pieces being accompanied by 
a large mass of small fragments. These are carefully sorted and 
all those which are free from visible imperfections, or can be readily 
detached from such defects by the aid of chipping hammers, are laid 
to one side for further treatment. 

These rough broken lumps are next moulded into the shape of plates, 
blocks, or discs, depending upon the use to which they are to be put 
by the optician. To accomplish this the glass is reheated in mould 



until it almost melts. Tills is done in a long, tunnel shaped furnace 
wliich is lieated to a red heat at one end while the other end is just 
cool enough to allow the moulds to be pushed in. After the glass 
has been moulded to the desired shape it is placed in the final anneal- 
ing kiln where it is cooled for ten to twelve days. When cool the 
glass is polished on both sides and carefully examined for any remain- 
ing defects. These pieces of glass are now termed blanks, and are 
ready to be cut into lenses and other optical ware. The yield from 
each pot usually amount to only ten to twelve per cept of the total 
glass melted in the pot, twenty per cent being considered a very sat- 
isfactory production. 

When large lenses are made, in which absolute freedom from stress 
acquired in cooling is necessary, the final annealing must be carried 
out with extreme care. A special type of annealing oven has been 
designed for this purpose in which the source of heat, the tempera- 
ture, and the rate of cooling can be automatically controlled. This 
consists of a very thick, cylindrical shaped copper vessel, on which 
a large gas flame plays. The glass is placed inside of this cylinder. 
The temperature of the interior is measured by means of the pressure 
of mercury vapor, which is balanced by a column of mercury in an 
open tube, whose heights regulates the flame. It has been found 
that the" highest temperature necessary to make all stress vanish is 
465^0., while the lowest temperature required to insure complete 
hardening is about 370°C. The fall of 95*^ is spread over an interval 
of four weeks by means of this annealing device. 

* •' 'i 



J 0000,000 




• » • 




Wesf Virginia 
New Jersey 

Wew YorK. 


vflifPiiJ*^ showing value of glass production of soven leading states from 1880 
- - * to IIKM). Compiled from United States Census Reports. 

• • 



(Taken from Reports of the United States Census.) 

Table 1. 
Value of Glass Produced In the United States. 






West Virginia. 

New Jersey, 


New York, 





All other states, 

United States, 























































*No figures available. 

The above table shows that Pennsylvania is by far the most import- 
ant glass producing State in the Union, having in 1909 produced 
35.6% of the total output of glass in the country. Its rank in this 
resi>ect as compared with other glass producing states is better 
brought out by the production diagram shown in Plate LI I. Western 
Pennsylvania has become the great center of the glass industry in 
this country on account of the large supplies of cheap fuel, both coal 
and natural gas, which it possesses, and on account of its proximity 
to the important markets for glass. Another factor of perhaps some- 
what less importance is the large deposits of glass sands which occur 
in the State. The location of the different glass plants in operation 
in 1914 in Pennsylvania are shown on the map of the State accom- 
panying this report. 

Table 2. 

Value of Glass Production In Pennsylvania In 1909 by Varieties. 

Building glass (plate and windew), $14,958,649 

Pressed and blown glass, — 9,847,228 

Bottles and Jars _ 7,778!787 

Other varieties not Included in above, 233!272 

Total $32,817,936 



Table 3. 

Statistics of the Glass Industry in Pennsylvania in 1909. 

Number of establishments, — - 112 

Persons engaged in the Industry (total), 24,924 

Proprietors and Arm members 34 

Salaried employes 1,180 

Wage earners (average number), 23,710 

Capital invested $58,632,000 

Salaries paid, 1,730.000 

Wages paid 13,436.000 

Cost of materials used, 12.634,000 

Value of products, $32,817,936 

Table 4. 
Pot and Tank Furnaces in the United States and in Pennsylvania jji 1909. 

In Operation, 

United States. — 

Pennsylvania, >. 

370 pot furnaces (4945 pots) 
369 continuous tanks (3759 

73 intermittent tanks (433 

tons capacity) 
144 pot furnaces (2,086 pots) 
99 continuous tanks (1178 

26 intermittent tanks (145 

tons capacity) 


59 pot furnaces (697 pots) 
48 continuous tanks (436 

13 intermittent tanks (56 

tons capacity) 
23 pot furnaces (301 pots) 
12 continuous tanks (93 

6 intermittent tanks (27 

tons capacity) 





In the annual production of glass sand Pennsylvania ranks as the 
leading state. In 1914 there were 512^718 tons of glass sand produced, 
valued at $611,173." This was 32% of the total tonnage and 39% 
of the total value of the glass sand produced in the United States 
during that year. In 1915 the production was 455,512 tons, valued 
at $550,706, as reported by operators to the United States Geological 

Pennsylvania holds this important position for two reasons. One 
is that excellent deposits of pure quartz sandstone suitable for crush- 
ing into glass sand are available in various parts of the State, and 
the other is that the western part of the State offers an excellent 
market for such sands, as a large portion of the glass factories of 
the United States are there located, for economic reasons already 
discussed in a previous chapter. 

Location of the Industry. 

At present the glass sand industry is practically confined to t\vo 
parts of the State, namely: the central portion, and the western part. 
Of these the central area is by far the most important, both as re- 
gards the total tonnage of glass sand produced and its better quality 
for glass making. The productive area is confined to several locali- 
ties in Huntingdon and Mifflin counties, in the vicinity of Mapleton, 
Vineyard, and Granville along the main line of the Pennsylvania Rail- 
road, between Huntingdon and Lewistown. In the western part of 
the State the workable deposits are distributed over a much greater 
area, but the quality of the sandstone available is not as good as that 
of central Pennsylvania. In this region glass sand quarries are be- 
ing operated in Elk, Fayette, Forest, Jefferson, Venango, Warren and 
Westmoreland counties. 

Formations Involved. 

Deposits of sand and sandstone of sufHcient purity to be suitable 
for glass sand occur in several of the geological formations present 
in Pennsylvania. For the benefit of those who are not familiar with 
the various eras and periods into which geologic time has been divided 
the following table, taken from Chamberlin and Salisbury's Textbook 
of Geology, will probably make this part of the discusion more in- 

n.'S. Mineral Resonrcea of the United States. Part IT, Non-Hetala, 1914. U. 8. Geolo^cal Bnrrcj, 
p. 278. 


telligible. The different periods are given in their order, beginning 
with the most recent. 







{ Human or Recent. 
/ Pleistocene or Glacial. 

















The glass sands of central Pennsylvania are derived from the Oris- 
kanj formation, which is one of the formations deposited over this 
portion of Pennsylvania during Lower Devonian time. Those of the 
western part of the State come from the Pottsville formation, the 
lowest member of the Pennsylvanian in this State. Quartemary 
deposits along certain of the river valleys of southwestern Pennsyl- 
vania were at one time made use of in the manufacture of cheap 
grades of glass, but with the extensive exploitation of the better grade 
of sand derived from the Pottsville, and the practical exhaustion of 
the valley deposits, they are not longer of economic importance. 
There are, therefore, at the present time only two formations, the 
Oriskany and the Pottsville, that are the source of all the glass sand 
produced in the State. Of these the Oriskany is the most important. 




At its type locality in Oneida county, at Oriskany Falls, in central 
New York, the Oriskany formation has a thickness of about twenty 
feet, and consists of nearly pure, white, fossiliferous quartz sand rock. 
It differs considerably, however, both in composition and in thickness 
over the large area in which its outcrops occur in the eastern part of 
the United States, the composition ranging all the way from a prac- 
tically pure quartz sandstone to a siliceous limestone, with thick- 
nesses varying from a few inches up to several hundred feet. 

Character and Distribution of the Oriskany Formation. 

The succession of Silurian and Devonian formations as they occur 
in New York, and the position of the Oriskay among them, is shown 
in the following table taken from Handbook 19, of the New York 
State Museum: 

Chautauquan, . 

[ Ohemung beds. 
Oatskill sandstone. 
Portage beds. 
Naples beds. 1 

Senecan, - 

Ithica beds. } local facies. 
Oneonta beds. J 
Genesee beds. 
Tully limestone. 


Hamilton beds. 



[Marcellus beds. 
Onondaga limestone. 

Ulsterian — 

Schoharie grit. 
Esopus grit. 


Oriskany sandstone. 
Port Ewen limestone. 
Becraft limestone. 


New Scotland limestone. 


Kalkberg limestone. 
Coeymans limestone. 

Manlius limestone. 

Oayugan — 

Rondout waterlime. 
Oobleskill limestone. 

Salina beds. 

Guelph dolomite. 



Lockport dolomite. 

Clinton beds, including Rochester shale 
at top. 

[Medina sandstone, including Oneida con- 



Oswego sandstone. 

In Albany County, New York, southwest of the city of Albany, the 
Oriskany sandstone has a thickness of but one op two feet. West- 
ward, in Schoharie County, the thickness increases somewhat. Id 
the West Hill section, near Schoharie, it has a thickness of 6 feet 3 
inches."* Here it consists of a dark siliceous and very fossiliferous 
limestone, apparently a mixture of quartz and lime sand 

36. New Tork State Musenin Bulletin 02» 1906. 


graiob. At this place it overlies the Port Ewen limestone and is in 
turn overlain by the Esopus shale. Further west, in southern Herki- 
mer County, it disappears entirely, but in Oneida County, in the vi- 
cinity of Oriskany Falls, the locality after which the formation was 
named, it is again represented by 20 feet of nearly pure quartz sand- 
stone. Westward, it thins again, until at Manlius, in Onondaga 
County, it has decreased to one foot, five miles further west it 
again increases to 3 feet 6 inches. Four miles beyond this point it 
thins to 1 foot 6 inches and one and one-half miles further decreases 
to 6 inches and finally disappears entirely. In this region the for- 
mation is represented by a very light gray, occasionally pinkish, 
granular quartzite. In some of the localities the sand grains are 
well cemented and the rock durable, while at others it is friable and 
weathers to a rusty brown." It rests upon 40 feet of limestone 
which belongs to the New Scotland and Coeymans formations, the 
Becraft and Port Ewen limestones being here absent.^^ Overlying 
it is the Ononadaga limestone. The sandstone appears again at 
Split Rock, southwest of Syracuse, and thickens going westward un- 
til at Skaneateles Falls it is 18 feet thick. Beyond it thins rapidly 
until six miles westward it is down to 10 inches. From this point 
westward, with two exceptions, there are no more large lenses ob- 
servable, the formation being represented by a thin sheet of sand- 
stone, seldom more than a few inches in thickness. In the Buffalo 
region the formation disappears as a continuous sheet and is repre- 
sented only by masses of dark shale and a conglomerate composed 
principally of small water worn fragments of water lime in a matrix 
of indurated clay, present in well defined erosion channels and irreg- 
ular depressions in the top of the underlying water lime of the Coble- 
skill formation. All of the Devonian formations of eastern New 
York below the Oriskany, together with that portion of the upper 
Silurian above the Cobleskill, are absent in this region.'* 

Beyond the Niagara river in Ontario the Oriskany reappears irreg- 
ularly over a very limited area and finally disappears. Where it 
is present the thickness ranges from 6 to 25 feet.*' It varies some- 
what in composition. In some places it consists of a white, compact 
quartzite, while in others it is made up of coarse grains of quartz, 
some of them being an eighth of an inch in diameter, and pretty well 
rounded. Occasional grains of feldspar are also present. Some- 
times the rock is slightly calcarous. Fossils are abundant.*** 

South of Albany, New York, at Becraft Mountain, on the east side 
of the Hudson river, near Hudson, the Oriskany is represented by a 

.•^7. »w York State Mnwura BtiJlpfln fi2. 190R. 

?H. N(»w York State Musetim Bnllcttn 09. 1006. 

SO. BnllMln Ooolotrtcal Society of America, Vol. 11, pp. 241-S32. 1900. 

40 Cnnadlan Oeological Surrey. Report of projp'esa from its commencemeDt to 1863. pp. 359-389. 


stratum 1 to 2 feet thick, varying in composition from a siliceous lime- 
stone to a quartzite rich in fossils, it is underlain "by the Port Ewen 
limestone and overlain by the Esopus and Schoharie grits. Still 
further south, in the vicinity of Kingston, in Ulster County, the thick- 
ness increases, being 5 to 60 feet in this region. The formation here 
consists of a quartz conglomerate and sandstone or quartzites, cal- 
careous quartz and rock and siliceous lime sand rock. It is likewise 
underlain by the Port Ewen limestone and covered by the Esopus 
and Schoharie grits.*^ 

A typical specimen of the calcareous quartz sandstone from the 
Oriskany formation, collected by the writer in the vicinity of King- 
ston, has a light gray color, and consists of quartz grains cemented 
by calcite. Under the microscope, in this section, many of the grains 
are seen to be pretty well rounded, the majority of them having at 
least had their comers rounded off. Dust like particles, too fine to 
be determined, but probably in part consisting of fluid or gaseous in- 
clusions occur in most of the grains. These often occur along defi- 
nite lines which under the high power of the microscope are seen to 
be incipient fractures. Hair like inclusions of rutile are present in 
some of the quartz grains. Under the cross-nicols most of the grains 
prove to be portions of individual crystals of quartz, but a few are 
seen to be made up of an aggregate of still smaller grains. Many of 
the grains show strain shadows or undulatory extinction under the 
cross nicols. The space between the grains is occupied by calcite. 
Plate LIII shows the appearance of a thin section of this rock under 
the microscope. Another thin section of a more calcareous specimen 
was also examined. In this case the calcite is in excess of the quartz 
grains. The latter show very ragged outlines. Apparently the 
quartz has been attacked on the inargins and replaced in part by cal- 
cita Almost all of the grains show undulatory extinction. Inclu- 
sions are not abundant. 

To the southwest of Kingston, in southeastern New York and ad- 
jacent portions of New Jersey, the Oriskany becomes involved in the 
Appalachian folding, which is described in a later paragraph under its 
geologic history. Isolated outcrops occur along a belt starting north 
of Greenwood Lake and extending south beyond Newfoundland, while 
the main belt of the formation continues south, from near Kingston, 
through New Jersey into Pennsylvania. Along the west shore of the 
southern end of Greenwood Lake the formation consists of a white, 
light gray, or buff colored quartzite, containing much coarse sand and 
a considerable number of quartz pebbles. It has a thickness of 
about 28 feet. In the Newfoundland region the thickness is about 

41. New Toric State Mnsenni Bulletin 92. 1906. 


50 feet. Some portions of the quartzite at this place are calcareous 
and weather to a loose grit. These portions are usually fossilifer- 
ous.*^ Along the upper Delaware valley the strata referred to the 
Oriskany have a thickness of 170 feet. They are for the most part 
siliceous limestones, but the summit of the formation along the south- 
ern half of Wallpack Ridge becomes a sandstone. These beds rest 
upon 80 feet of shale which have been referred to the Port Ewen 
of New York, on account of their position. Overlying the Oriskany 
are 375 feet of grit correlated with the Esopus of New York. A 
limestone, probably the Onondaga, rests upon this grit.** 

The Oriskany enters Pennsylvania in southeastern Monroe county, 
as a single outcrop, in the form of a narrow belt dipping towards the 
northwest It continues southwest along this belt through south- 
eastern Carbon and Schuylkill counties. From that point on, how- 
ever, there are a large number of nearly parallel outcrops, running 
in a general southwesterly direction and occupying a belt approxi- 
mately 56 miles wide, in Perry, Juniata, Mifflin, Huntingdon and 
Centre counties. This is the area in which folding occurred at the 
close of the Paleozoic Era, so that the Oriskany has been brought to 
the surface many times on the flanks of the eroded anticlines. 

Along Broadhead Creek, near the Delaware Water Gap, the Oris- 
kany formation consists, from the top down, of 5 feet of pebbly, mas- 
sive, calcareous sandstone, 38 feet of cherty, fossiliferous, calcareous 
shale, and 1 foot of quartz conglomerate. It is underlain by a fossilif- 
erous, argillaceous limestone and overlain by a shale.** South, in the 
vicinity of Bossardsville, in Monroe county, the formation consists of 
a grayish-white, rather coarse grained sandstone, with many small 
flat pebbles, which have a darker appearance than the enclosing 
matrix. It is usually much disintegrated and has been used in the 
mnufacture of bottle glass. No exact measurements are possible 
here, but it is estimated the sandstone has a thickness of 150 to 
200 feet." 

Continuing southward, in the vicinity of the Lehigh Gap, the Oris- 
kany formation consists of sandstone and conglomerates of resistant 
character that are responsible for Stony Ridge. The formation is 
divisible into two portions. The upper member is composed of a 
coarse sandstone or conglomerate, varying in thickness from 150 to 
175 feet. The cementing material is mainly calcareous and its re- 
moval in many cases causes the rock to disintegrate. Numerous 
sand quarries are, therefore, located along the ridge. The sand 
grains are usually well rounded and the stone has a white to light 

42. Bulletin, Oooloirtcal Society of America. Vol. 5. pp. 867-S94. 1804. 

43. Journal of GeoloRT. Vol. 17. pp. S51-370. 1009. 

44. Second Oeolofrlcal Sarrey of PenneylTanla. Pinal Smmnary Report. Vol. 2, pp. 1034-1141. 

45. Second Geological Snrrey ©f Pennsylvania. Report O. «, pp. 288-284. 1881. 


ydlow color. The lower member of the formation consists of quart- 
zitic shales, which are very fossiliferous. Those shales vary in thick- 
ness from 200 to 300 feet/« 

In Perry county the formation nowhere exceeds 20 to 25 feet in 
thickness. It varies from white, through yellow to red in color, and 
in hardness from loose sand to a flinty rock. In some places it is a 
fine conglomerate made up of a mass of small, white quaHz pebbles, 
while in other places it is a sandstone. In the vicinity of New 
Bloomfield, central Perry county, the grains are more or less round- 
ed.*' According to Grabau the Oriskany of Perry county overlies 
90 feet of flinty shale, the upper portion of which contains New Scot- 
land fossils.*^ 

To the west of this area in Mifflin and Huntingdon counties the 
Oriskany sandstone reaches its maximum development. Northwest of 
Ijewistown, according to Dewees*^, the Oriskany sandstone has a thick- 
ness of 110 feet and is overlain and underlain by shale. Remnants 
of it are here preserved in three synclinal flexures. While in most 
cases it is considerably stained by limonite, there are several places 
where it has weathered to a practically white, pure quartz sand. The 
formation as exposed in the vicinity of Lewistown is very fossiliferous, 
especially in its upper portion. At McVeytown, about 12 miles south- 
west of Lewistown, it reaches a thickness of 140 feet. Here under 
favorable conditions it has also in places disintegrated to a white 
quartz sand through weathering. Twelve miles further to the south- 
west, at Mount Union, along the same belt of outcrops as those occur- 
ring at Lewistown and McVeytown, it has decreased in thickness to 
95 feet. The exposures in this* vicinity are poor, but boulders mark- 
ing the outcrop indicate that the formation consists of a fairly pure 
quartz sandstone. 

Four miles west of Mount Union, on the opposite limb of the Jacks 
Mountain anticline, in the vicinity of Mapleton, the Oriskany again 
reaches a thickness varying from 125 to 212 feet. Here it also con- 
sists of a practically pure quartz sandstone or quartzite, with occas- 
ional thin fosailferous conglomeratic layers containing quartz pebbles 
up to three eighths of an inch in diameter. Continuing westward, 
just beyond the town of Huntingdon, the Oriskany occurs in the east- 
ward dipping flank of the syncline of which the outcrop through 
Mapleton forms the eastern limb. Here along Warriors Ridge, in 
the vicinity of McConnellstown, it has a thickness of only 60 feet. It 
is still a fairly pure quartz sandstone but contains more oxides of 
iron. Still further to the westward, at Altoona, the Oriskany hori- 
zon appears at the surfa(je for the last time, dipping westward un- 

46. Top. and Gcol. Surr. Penna. Report No. 4, pp. 62-S6. 

47. Second Geol. Sarr. of Penna. Report F2. 

48. New York State Maseum. Bnll. 02. 1916. 

40. Sc«ODd Geol. Sury. of Penna., Report F. p. 40. 


demeath the later Paleozoic strata which underlie the Appalachian 
plateau. In this region it has a thickness of only 20 feet and consists 
of a thick bedded, generally coarse grained, gray or buff colored sand- 
stone.^® It is overlain by the Marcellus black shale, the Onondaga 
apparently being absent. 

Southward from its area of maximum development in MifQin and 
Huntingdon counties, the Oriskany outcrops continue in Bedford and 
Fulton counties wherever this horizon of the Devonian has been 
brought to the surface by the erosion of the anticlinal folds, but it 
rarely exceeds a thickness of 90 feet.'^ It is still a sandstone but 
in places considerable calcareous material is present, thus strongly 
contrasting it with the Juniata valley section just described, where 
in no case in the numerous thin sections of the rock examined by the 
writer under the microscope was any calcite noticed. 

The Oriskany of Maryland has been studied in detail and described 
at considerable length in a recent monograph on the Lower Devonian 
published by the Maryland Geological Survey. The outcrops form a 
continuation of the belt which occupies the Appalachian mountain 
region of central Pennsylvania and extend across Maryland into West 
Virginia. In Maryland the Oriskany consists in its lower portion 
of a black cherty shale, which has been called the Shriver Chert mem- 
ber and in its upper part of a calcareous sandstone or arenaceous lime- 
stone, to which the term Ridgeley sandstone has been applied. The 
Shriver Chert member consists of a dark silicious shale, containing 
large quantities of black, impure chert in the form of layers or no- 
dules. In the most easterly of the Oriskany outcrops in Maryland 
it is absent, while in those farthest to 'the west it reaches a total thick- 
ness of 100 feet. The Ridgeley sandstone member is composed of a 
calcareous sandstone which passes in places into an arenaceous lime- 
stone because of the great development of calcareous ce- 
ment. It also contains conglomeratic * beds, one of which 
in the vicinity of Cumberland contains pebbles resembling 
grains of wheat. Upon weathering, the calcareous cement is dissolved 
out by the surface waters and the rock disintegrates, forming sand 
and large boulders of samlstone. The character of the rock under- 
goes a change towards the eastward, becoming more calcareous, until 
in the North Mountain area it is a limestone sufficiently pure to be 
used as a source of lime. Here it contains numerous beds of chert. 
In thickness the Ridgeley member varies from 250 feet in the western 
exposure to 50 feet or less at the North Mountain outcrop. The 
boundary between the two members of the Oriskany is not sharp. 
The amount of chert diminishes in the upper part of the Shriver 
member and thin beds of sandstone appear, forming transition beds 

50. Journal of Geolofpy, Vol. 14, 1906, pp. 018-030. 
61. S<H;ond Geol. Snnr. of Penna. Keport T2. 


into the overlying sandstone. In Maryland the Oriskany in most 
places comes to rest upon the New Scotland, the Becraft appeanng 
only in Washington county, where it consists of an arenaceous lime- 
stone with much biterbedded chert, having a thickness of about 85 
feet At the top of the Oriskany there is evidence for at least a 
short erosional unconformity, followed by the deposition of the Rom- 
ney shale, which in its lower part contains a fauna of Onondaga age. 

South of Mar}'land, in West Virginia, especially in the area cov- 
ered by the Pawpaw-Hancock folio of the tJnited States Geological 
Survey, the Oriskany formation is again developed to an extent com- 
parable to the deposits of central Pennsylvania, except that often 
considerable quantities of calcareous material are present in it. In 
general it is a pure white to gray calcareous sandstone with minor 
amounts of quartz conglomerate. Calcareous material predominates 
in places, especially in the eastern areas, and forms a limestone suf- 
ficiently pure to be burned for field lime. Further west in the area 
along Tonoloway and Warm Spring Ridges, the sandstone is entirely 
free from lime at the surface and is quarried for glass sand. A fine 
quartz pebble conglomerate is usually present at or near the top, 
whose pebbles range up to a quarter of an inch in diameter. Along 
Warm Spring Ridge the formation has a total thickness of about 150 
feet, while on Tonoloway Ridge it reaches a thickness of 417 feet. 
The Oriskany of this area is very fossiliferous. In the sandstone the 
fossils are present only as interior casts, as in the case of the Penn- 
sylvania occurrances, while in the calcareous portions of the forma- 
tion, in the eastern area, the entire shells are usually present. The 
fossils are all characteristic of the upper Oriskany of New York and 
as the formation comes to rest on limestone of Becraft and New 
Scotland age (with the exception of one occurance exposed in the 
Western Maryland railroad cut opposite Great Cacapon, io the west- 
ern part of the area) an erosion unconformity evidently exists, here 
represented by the absence of the lower Oriskany. In this area the 
Oriskany is also overlain by the Romney shale, the lower member of 
which contains fossils of Onondaga age. There is evidence of a 
minor erosion unconformitv between this member and the sandstone, 
represented by the irregular surface of the latter at the contact and' 
by the sudden transition from sandstone into shale. A conglomer- 
ate also occurs locally at the base of the Romney. 

To the sonthwestward, in Virginia, the Oriskany has been described 
by N. H. Darton in the vicinity of Stanton, as consisting of from 1 50 
to 300 feet of buff colored, fine grained, massive sandstone, contain- 
ing an abundance of casts and impressions of fossils.*' The forma- 

52. U. 8. Geol. Snnr. Folio 14. 


tion at this place has b^en called the Monterey sandstone. To the 
southeastward it thins rapidly and in places is entirely absent, due 
to an erosional unconformity. 

In northeastern Alabama and northwestern Georgia the Oriskany 
formation is represented by what is locally called the Frog Mountain 
sandstone. In the vicinity of Home, Georgia, it is a formation of 
chert and sandstone, carrying fossils of Oriskany age. The sand- 
stone is either a white, quartzitic variety, or a yellow, porous one, 
with some feldspar. It rests with an erosional unconformity upon 
the Rockwood formation of the middle Silurian and is overlain by 
a black shale, known as the Chattanooga shale, also of Devonian age. 
In the Birmingham, Alabama, region it is rather coarse quartz sand- 
stone or quartzite, ranging in thickness from 4 to 20 feet, also resting 
upon the Clinton of Rockwood formation of the middle Devonian and 
overlain by the Chattanooga shale. 

In going westward from central Pennsylvania attention has al- 
ready been callefd to the fact that the Oriskany formation passes un- 
der beds of later age. This horizon of the Devonian does not again 
come to the surface until central Ohio is reached, where Devonian 
strata have been exposed by the erosion of the Cincinnati dome. Here, 
however, the Oriskany has disappeared along with all of the strata 
representing the lower Devonian of the Appalachian Mountain region, 
so that the Onondaga limestone (locally called the Columbus lime- 
stone in Ohio) comes to rest upon the Monroe formation of the Upper 
Silurian, indicating an erosional unconformity during lower De- 
vonian time, during which this part of Ohio was dry land. To the 
southwestward, in north central Kentucky, this uneouforinity repre- 
sents a still greater interval of time, as here the Onondaga (Jeffer- 
sonville) limestone comes to rest upon the Louisville limestone of 
the Middle Silurian. 

Geologic History of the Oriskany Formation. 

From the preceding description of the Oriskany formation it is seen 
that it consists for the most part of a quai*tz sandstone or quartzite, 
which in part of the area over which it is distributed is exceedingly 
•pure, so that where it has been sufficiently weathered it can be used 
as a source of glass sand. Occasionally thin beds of fine conglom- 
erate are found in it, while at other times it is either argillaceous or 
calcareous. The fact that marine fossils are found in it indicate 
that it was deposited upon the sea floor, but in as much as it is a 
comparatively coarse sediment over most of the area where it is 
found, it shows that the shore line could not have been very far 
away from the place where it was laid down. It represents a near 
shore, shallow water deposit, laid down in a narrow arm of the 

Paleogeograpliy of the Eastern United States during Oriskany time. 


sea which occupied the present Appalachian Mounta'in region dur- 
ing Devonian time. 

Plate LIV shows the probable maximum extent of this interior 
sea as indicated by the present distribution of the Oriskany sediments 
over the eastern United States. A connection with the Atlantic 
Ocean is shown by the way of the St. Lawrence valley region. The 
map shows a land area along the present Atlantic border of the 
United States, extending out some distance into the Atlantic from 
the present shore line. The evidence for the existence of this land 
area is furnished by the coarse nature of much of the Oriskany sedi- 
ments found in the Appalachian region. Such sediments could only 
be deposited near shore. A study of the formations exposed to 
erosion around the shores of this interior sea during Devonian time 
indicates that along its western margin, (with the possible exception 
of a small area in northern Ohio, where the Sylvania sandstone of the 
Upper Silurian, which has a thickness of about 20 feet feet may have 
been exposed to erosion), no other formations except shales and lime- 
stones were furnishing sediments. This leaves only the land area to 
the east and to the north as a possible source for the extensive sand- 
stone deposits of Oriskany age in central Pennsylvania and north- 
eastern West Virginia. It is not likely that much material was 
washed as far south as central Pennsylvania and northern West 
Virgina from northern New York State, so that undoubtedly the 
source of the sands was a land area exposed to erosion to the east, 
from which streams flowed in a westerly direction into the Oriskany 
sea, washiug sands down with them. Below the Oriskany sandstone 
of Pennsylvania are found, besides limestones and shales, the Tus- 
carora sandstone, which is a very pure quartz sandstone ; the Juniata 
formation, made up in great part of sandstone, and a considerable 
thickness of Cambrian sandstones, of the lower Paleozoic, which rest 
upon pre-Cambrian gneisses and schists, which also contain abundant 
quartz grains. It is highly probable that parts of all of these for- 
mations were exposed to erosion during Oriskany time over portions 
of the eastern land area, as all occur outcropping over areas farther 
east than any of the known Oriskany outcrops. These formations, 
therefore, must be considered as the source of the present Oriskany 

The question arises as to how the quartz grains, in places, were so 
completely separated from the minerals which accompanied them in 
the original rocks as to give rise to sand deposits which analyze over 
99% silica, as is the case in central Pennsylvania and northeastern 
West Virgin!^. The methods by which nature accomplishes this 
have already been discussed in a previous chapter, dealing with the 
raw materials used in the manufacture of glass, so that it is only 


necessary liere to state briefly the conditions which must have pre- 
vailed over this area during Oriskany time and the interval just 
prior to it, which resulted in this type of deposit. 

The lower Devonian formations, just below the Oriskany, are pres- 
ent only in a small portion of the area occupied by the Oriskany for- 
mation itself, namely eastern New York, central Pennsylvania, west- 
em Maryland, and northeastern West Virginia. Passing southward 
from this area the Oriskany comes to rest upon lower and lower for- 
mations until in northern Alabama it lies upon the Clinton formation 
of the Middle Silurian. The same thing holds true in going westward 
from central New York, where in the vicinity of Buffalo only a few 
thin patches of the uppermost Oriskany are found on top of the Coble- 
skill limestone of the Upper Silurian. This shows that during this 
part of the Devonian the seas were much more restricted. Ahao dur- 
ing this interval only limestones and shales were deposited over the 
areas of deposition, which shows that the land to the east was low 
lying and, therefore, not undergoing the rapid erosion necessary to 
furnish coarser sediments. 

When land areas are low, chemical decomposition is the predomi- 
nating process of weathering, rather than mere mechanical disinte- 
gration of the rocks. As has already been pointed out, in the previ- 
ous chapter^referred to, such a thorough decomposition is necessary 
as the first stage in the formation of a pure quartz sandstone, in order 
that all the silicate minerals accompanying the quartz in the rocks 
will be thoroughly altered and disint^rated into soft, readily pulver- 
ized secondary products, leaving the quartz grains free. Then it 
is only necessary to have these grains separated from this thick mantle 
of residual soil by some sorting and transporting agent, such as a 
running water or the wind. 

In the case of the Oriskany sandstone some of the formations from 
which it was derived were already fairly pure quartz sandstone, run- 
ning as high as 07% in silica, such as the Tuscarora sandstone, for 
example. This fonnation reaches a considerable thickness wherever 
the Oriskany sandstone is well developed, so that much of the sand 
of the latter may have come from parts of this formation, exposed 
to erosion along its eastern outcrops during Oriskany time. 

Running water, in the form of sreams, apparently was the prin- 
cipal transporting agent which carried the Oriskany sands from the 
eastern land area into the shallow Appalachian sea. At the begin- 
ning of Oriskany time this land was elevated slightly, so that coarse 
material was washed down by the streams. This is indicated by the 
fact that where, during the lower Devonian, only limestones and 
shales had been accumulating, sands were deposited at this stage. 
The thickest beds of sand were laid down at the mouths of the larger 


streams in the form of large deltas, while the fine material was car- 
ried farther out into the sea, where it finally settled out around the 
margins of the deltas. Wave action and shore currents undoubtedly 
also played a part in the separation of. the coarse material from the 
fine. In the area beyond, and between the deltas, in places a little 
limestone also accumulated. 

Wind action may also have played a part in the separation of the 
quartz grains from other accompanying minerals, although the evi- 
dence for this is not at all conclusive. None of the Oriskany sand 
stones examined by the writer under the microscope showed as per- 
fectly rounded grains as are often found in wind blown sands. In 
the description of a section of calcareous sandstone from Kingston, 
New York, attention has already been called to the fact that many of 
the grains show imperfect rounding. In numerous sections of Oris- 
kany sandstone from central Pennsylvania examined under the micro- 
scope, they were seen to be made up of an interlocking mosaic of 
angular quartz grains. This angular shape, however, may in part 
be due to secondary changes which have occurred in the rock since 
it was deposited. Silica is the bond of these sandstones and it has 
crystallized around the original grains of sand in such a manner that 
the new molecules of silica have taken on the same crystallographic 
orientation as those of the grains about which they formed, so that 
under the microscope the two appear to be continuous. It is only 
occasionally that the original shape of the grain can be determined 
fit>m the distribution of inclusions in it. Rounded grains can at 
times be detected in this manner in the Oriskany sandstone of Penn- 
irylvania. As has already been stated the Appalachian sea was much 
more restricted during the early part of the Devonian, just prior to 
the deposition of the Oriskany. It is possible that sands were washed 
out onto the low lying plain, which was later occupied in part by the 
Oriskany sea. Winds may have shifted these sands about and sepa- 
rated much of the finer material from them in a manner already de- 
scribed. Then when the sea encroached upon this territory the waves 
reworked it and marine fossils became imbedded in it. Also with 
the elevation of that part of the plain to the east streams picked up 
the sand again and carried it westward to deposit it on their deltas. 
In some of the Oriskany sandstones of central Pennsylvania distinct 
cross bedding of the stream or fluviatile type may be recognized. 

After the Oriskany sediments had been deposited conditions favor- 
able either for marine or continental sedimentation, with only oc- 
casional periods of erosion, continued to exist throughout the Appa- 
lachian area until the end of the Paleozoic. At the close of this 
era a great crustal disturbance set in over the region occupied by 
the Appalachian trough, which had been gradually subsiding through- 


out the Paleozoic. The thick series of horizontal strata which had 
accumulated were now subjected to enormous lateral pressure brought 
about by the gradual shrinkage of the earth, which caused them to 
become folded into a series of anticlines and synclines, following a 
northeast and southwest trend. At the same time they were ele- 
vated high above sea level. 

During this period of folding the Oriskany sands of central Penn- 
sylvania were converted into hard quartzite, in part by recrystaliza- 
tion of the quartz grains and in part by the deposit of seconda^ silica 
around them. 

The region has not been submerged below sea level again since this 
disturbance, but has been exposed to erosion continuously from that 
time to the present. Several periods of vertical elevation have oc- 
curred, which from time to time have re-elevated the area after it 
had been worn down almost to sea level by erosion. The first one 
of these uplifts occurred towards the close of the Cretaceous. By 
that time the Appalachian area had been worn down to a nearly 
level plain, standing only very slightly above sea level. Much of 
the Paleozoic strata, especially along the arches or anticlines of the 
folds, had been removed by erosion so that the lower Paleozoic strata 
had been bi*ought to the surface in places. After this uplift erosion 
again became active and broad valleys were formed along the softer 
strata, exposed to erosion, leaving only the more resistant ones, 
standing out as long, nearly parallel ridges, the tops of which still 
approximately approached the level of the old elevated Cretaceous 
peneplain. This period of erosion was again interrupted by an up- 
lift which occurred during early Tertiary time, causing the streams 
to again commence to incise their channels in the broad vaUeys de- 
veloped during the previous cycle of erosion. Since then there has 
probably been at least one other such movement, at the close of the 
Tertiary period. The tops of the higher ridges of central Pennsyl- 
vania, therefore, mark the level of the old erosion plain developed 
prior to the close of the Cretaceous. This accounts for the fact that 
they all have approximately the same level, thus furnishing an even 
sky line when viewed from the top of any one of them. The broad, 
nearly level areas which are usually more or less dissected by stream 
valleys between these ridges of resistant rock, represent areas under- 
lain by softer and more readily eroded formations. These areas were 
developed during the second cycle of erosion, after the Cretaceous 
peneplain had been elevated. THie valleys which are cut in them 
were formed after this second cycle was brought to a close by another 




Those portions of the Oriskany formation suitable for glass sand 
occur in two main areas, one in central Pennsylvania, confined mainly 
to Huntingdon and^ Mifflin counties^ and the other in northeastern 
West Virginia, in Morgan county. These portions of the formation 
owe their value as glass sand deposits to two causes. First, they 
were laid down under conditions which resulted in an almost com- 
plete separation of the quartz grains from other minerals, so that 
a very pure quartz sand resulted, which later on became consolidated 
into a sandstone or quartzite, and, secondly, these portions of the 
formation were later exposed to weathering under conditions which 
have resulted in the partial, or in places complete disintegration of 
the rock to friable sandstone or loose sand, without the infiltration 
of any iron bearing solutions. Wherever these two conditions have 
prevailed, and the formation has a sufficient thickness, it is suitable 
for glass sand. 

Characteristics Due to Conditions of Original Deposition. 

Attention has been called to the fact that only these portions of 
the Oriskany formation are suitable for glass sand in which consider- 
able weathering has occurred, so that the sandstone has been disinte- 
grated suflSciently to become friable. A number of thin sections of 
the least altered portions of the formation in the vicinity of glass 
sand deposits were therefore examined by the writer to determine 
what the rock was originally like, before it had undei^one any dis- 
integration. An excellent exposure of only very slightly weathered 
Oriskany sandstone is in the abandoned quarry of the Westbrook 
Glass Sand Company, a short distance northeast of Mill Creek, in 
Huntingdon county. It consists of a hard, bluish grey, vitreous 
quartzite, which in thin section under the microscope, with crossed 
nicols, is seen to be made up of an interlocking mosaic of angular 
quartz grains. An occasional grain of altered feldspar is present 
and minute quantities of iron oxide occur along a few of the irregu- 
lar incipient cracks developed between some of the grains of quartz. 
Dust like inclusions, too fi»e to be determined, are abundant in many 
of the grains. Occasionally a piece of quartz contains abundant 
rutile needles and now and then one with a few small prismatic 
crystals of apatite may be observed. Much of the quartz shows 
strain riiadows, revealed by undulatory extinction when viewed be- 
tween crossed nicols. From the distribution of the minute inclusions 


in a few of the grains it can be seen that originally some of them 
had a rounded outline, which has been obliterated by the crystalliaa- 
tion of additional silica around them, whose molecular orientation is 
similar to that of the original grain, so that the two behave as an 
unit when viewed between crossed nicols under the microscope. The 
secondary silica, however, is free from inclusions. The deposition of 
this silica has resulted in the tilling of all the original pore space of 
. the rock and forms the interlocking mosaic of quartz grains now seen 
under the microscope. Figure 1, i'iate LV, shows a photograph of 
this sandstone as it appears in this section between crossed nicols 
under the microscope. As seen from the above description the rock 
consists practically entirely of quartz grains, the small quantities of 
other constituents present being negligible. A chemical analjrsis of 
this rock shows it has the following composition: 

SiO. - 99.39% 

Al.O. 30% 

Fe.O., .12% 

MgO, none 

OaO „.- 29% 

H.O 17% 

TiO,. _ 03% 


Another sample taken from a ledge of the harder rock left in the 
northeast comer of the north quarry of the Pittsburgh White Sand 
Ck)mpany, south of Mapleton, Huntingdon county, consists of a white 
sandstone, grains of which can only be removed with difficulty with 
the fingers. Here and there through it are small specks of limonite. 
When examined in thin section under the microscope it shows a very 
much similar composition and texture to the specimen from the West- 
brook quarry. A few grains were also present in it which, from the 
distribution of their inclusions, appear at one time to have been 
rounded. One well rounded grain of hornblende was noticed. Un- 
doubtedly the alteration of this mineral, which is silicate contain- 
ing some iron, accounts for the scattered specks of limonite. An- 
other very much similar specimen from the Juniata White Sand Com- 
pany's quarry, south of the above locality, which was also speckled 
here and there with limonite, likewise showed a well rounded grain 
of hornblende in a thin section examined. The following screen 
analysis shows the size of the grains of sandstone encountered in the 
North quarry of the Pittsburgh White Sand Company: 



Screen Analysis of Sand from North Quarry of Pittsbursfh White Sand 


Remaining on 6 mesh (.131 inch diameter) » .42% 

Tnrough 6, remaining on b mesh (.OITJ inch diameter). .42% 

Througn 8, remaining on 10 mesh (.065 inch diameter), 1.73% 

'rnrougn 10, remaining on 14 mesh (.(M6 inch uiumeier), 1.57% 

Tnrougn 14, remaining on 20 luesn (.uiii8 inch aiameter), 2.42% 

Tnrougn 20, remaining on 26 mesn (.0^32 iucn diameter), 7.36% 

Through 28, remaining on 35 mesn (.0164 inch diameter), 18.90% 

Through 35. remaining on 48 mesn (.0116 inch diameter), 47.84% 

Through 46. remaining on 65 mesh (.0082 inch diameter), 14.71% 

Through 65, remaining on loO mesh (.0058 inch diameter), 2.18% 

Through 100, remaining on 150 mesh (.0041 inch diameter), .48% 

Through 150, remaining on 200 mesh (.0029 inch diameter), .37% 

Through 200 - 42% 


A Specimen of only partially weathered Oriskany sandstone taken 
from an outcrop on the southeast dipping limb of a narrow syncline, 
on whose northwest dipping portion the Gi*anville mine of the Penn- 
sylvania Glass Sand Company, southwest of Lewistown, Mifflin 
county, is located, consists of a hard white sandstone, stained with a 
little limonite along a few minute crevices. Under the microscope, 
in thin section, it is also seen to be made up of a mosaic of interlock- 
ing quartz grains, some of which between crossed nicols show undu- 
latory extinction. Dust like inclusions are also abundant in many 
of the grains, and from these it can be seen that some of the grains 
were originally rounded. The size of the grains of the Oriskany 
sandstone in this vicinity is indicated by the following screen analy- 
sis, made from a sample taken from the Granville mine. 

Screen Analysis of Sand from Sample of Oriskany Sandstone from the 

Granville Mine. 

Remaining on 14 mesh (.046 inch diameter), .01% 

Through 14, remaining on 20 mesh (.0328 inch diameter), .28% 

Through 20. remaining on 28 mesh (.0232 inch diameter), 1.31% 

Through 28. remaining on 35 mesh (.0164 inch diameter), 5.15% 

Through 35. remaining on 48 mesh (.0116 inch diameter), 20.77% 

Through 48, remaining on 65 mesh (.0082 inch diameter), 86.80% 

Through 65, remaining on 100 mesh (.0058 inch diameter), 24.32% 

Through 100, remaining on 150 mesh (.0041 inch diameter), 5.14% 

Through 150, remaining on 200 mesh (.0029 inch diameter), 2.91% 

Through 200 2.28% 


The Oriskany sandstone of Warriors Ridge, where the Juniata 
river crosses it juBt above Huntingdon, is a light buflf colored quart- 
zite. Under the microscope it is seen to also consist of an interlock- 
ing mosaic of quartz grains, some of which from the distribution of 
their inclusions appear originally to have been rounded. Dust like 
inclusions are abundant in many of the grains. An occasional grain 
with nitile needles or apatite is present. A little limonite or other 
iron oxide occurs between some of the grains, which give the rock its 
buflf color. This rock has weathered to a loose sand in places on 
Warriors Ridge, southwest of the river. A screen test of the sand 
gave the following results: 


Screen Test of Sand from Warriors Ridge. 

Remaining on 14 mesii, (.046 inch diameter), .20% 

Through 14. remaining on 20 mesh (.0328 inch diameter), 1.04% 

Through 20. remaining on 28 mesh (.0232 inch diameter). 2.41% 

Through 28. remaining on 35 mesh (.0164 inch diameter). 4.94% 

Through 35. remaining on 48 mesh (.0116 inch diameter), 14.24% 

Through 48. remaining on 66 mesh (.0082 inch diameter). 43.97% 

Through 65, remaining on 100 mesh (.0058 inch diameter), 30.12% 

Through 100, remaining on 150 mesh (.0041 inch diameter), 1.48% 

Through 150, remaining on 200 mesh (.0029 inch diameter), .50% 

Through 200 ~. 78% 


The sand has a light brown color, indicating that it contains too 
much limonite to yield a first class sand. 

Another sample obtained along Warriors Ridge south of Hunt- 
ingdon, between Entriken and Hummel station, also consists of a 
buff colored quartzite, which shows very much the same character- 
istics under the microscope as the specimen described irt)Ove, except 
that a little more iron oxide was present between the quartz grains. 
More of the grains showed that they were originally rounded. Some 
of the grains showed undulatory extinction between crossed nicols. 
Occasiolial grains of hornblende are present, one of which showed a 
secondary growth of a lighter colored amphibole around the original 
grain, whose crystallographic orientation was similar to that of the 
latter. All of the sands derived from the weathering of the quartzite 
between this locality and Huntingdon contain too much limonite to 
yield the best quality of glass sands. 

From the description of the above samples of Oriskany sandstone, 
from localities where these have yielded glass sand, it is seen that over 
the areas during the time they were deposited, conditions were such 
that nothing but quartz grains were laid down, as no other minerals 
occur in them, except now and then an occasional grain of hornblende 
or altered feldspar. Silica forms the bond between the grains. 
This siliceous cement has been deposited in crystalline continuity 
with the original quartz, as a new outgrowth of the grains, the new 
material extinguishing simultaneously with the grain about which 
it was deposited when viewed under the microscope between crossed 
nicols. The result is that a slice of the rock has the appearance of 
an irregular mosaic, between crossed nicols. This compacting and 
cementing of the Oriskany sands into quartzites, accompanied by the 
partial recrystallization of the quartz grains themselves along their 
points of contact, occurred after their deposition, probably during 
the time this formation was subject to the great lateral compression 
towards the close of the Paleozoic era, which brought about the folded 
structure of the Appalachian Mountains. 

Characteristics Due to Secondary Changes. 

After the Oriskany sandstone, together with the other Paleozoic 
formations of the Appalachian trough, had been compressed into a 


series of parallel anticlines and synclines running in a northeasterly- 
southwesterly direction, and elevated high above sea level, erosion 
set in. As has already been stated, sufficient time had elapsed by 
the close of the Cretaceous to allow the various destructive agents of 
nature to wear the whole region down to a nearly level plain, which 
stood only a short distance above sea level, and across which the 
major streams flowed in broad meandering courses in an easterly di- 
rection to the Atlantic. Through this erosion of the folded strata 
the Oriskany, which had been covered over the whole area by later 
Poleozoic sediments, was exposed at the surface in a series of nearly 
parallel narrow belts, which follow the trend of the folds. Toward 
the close of the Cretaceous the region was again elevated vertically 
above sea level. This time the uplift was not accompanied by any 
lateral compression. The stream again begto to cut their valleys 
downward, the major streams keeping their old meandering courses 
in an easterly direction towards the ocean, while the minor ones ad- 
justed themselves to the structure of the underlying rocks, by shift- 
ing their courses to the softer, more readily eroded formations. For 
this reason these streams in general flow either in a northeasterly or 
a southwesterly direction, as the outcrops of the various strata follow 
along this line, parallel to the axes of the folds. As has already been 
stated this cycle of erosion was again interrupted, after broad val- 
leys had been developed in the softer strata, by a third vertical up- 
lift, which occurred during early Tertiary time, and possibly by a 
fourth during the late Tertiary. 

When the Oriskany is first brought near the surface, and before 
it has undergone any change, it consists of a well cemented, pure 
quartzite over those areas where the glass sand deposits occur. In 
order for it to become available for glass sand it has to undergo 
sufficient disintegration through weathering to be converted into a 
friable sandstone or loose sand. This has occurred only along com- 
paratively small portions of its entire outcrop, where conditions were 
especially favorable. 

During the period of folding, and possibly also during the later 
crustal disturbances which resulted only in vertical uplift, the Oris- 
kany sandstone was fractured to a considerable extent, while the 
more plastic shales with which it occurs interbedded yielded by flow- 
age to the stresses to which they were put. This shattered nature 
of the Oriskany is illustrated in Plate LVI, which shows the south- 
west working face in the North Quarry of the Pittsburgh White Sand 
Company, south of Mapleton. These fractures allow the surface 
waters to get access to the sandstone formation wherever it is exposed 
at the surface, and from them this water gradually penetrates the 
sandstone itself along the contacts between the individual grains. 
The water undoubtedly dissolves a little of the silica, so that the 


Bandstone gradually becomes friable and eventually crumbles into 
a loose sand. This process is well illustrated in the abandoned quarry 
of the Westbroo]^ Qlass Sand Comp^ny^ northeast of Mill Creek, 
Huntingdon county. The strata at this place dip 60^ to the north- 
east. The outcrop of the Onskany on the northeast side is marked 
by a ste^ escarpment shown in Figure 1^ Plate LVII, which is a 
cross section of the quarry taken at right angles to the strike. Fig- 
ure 2, Plate LVII, is a reproduction of a photograph taken in the 
quarry looking northeast. At this place from 20 to 30 feet of that 
part of the sandstone nearest to the surface was disintegrated suf- 
ficiently to be utilized for crushing into glass sand. This portion is 
shown by the cross hatching in the section of Figure 1, Plate LVII, 
referred to above. Underneath, the formation was found to consist 
of a hard white to bluish gray vitrious quartzite. That the disinte* 
gration starts at the surface and out from the joint planes or frac- 
tures in the quartzite is clearly shown in this quarry. 

The bluish gray quartzite occurs farthest away from the surface, 
and also at some distance from the most pronounced zones of frac- 
turing, where surface waters have not yet had access to it Often, 
where joints do traverse it, the bluish gray color has disappeared 
along the fracture and the rock has become white, gradually grading 
out into the bluish gray color away from the joint. Where it has 
been acted on still more by surface waters the white quartzite has 
become disint^rated into a friable white sandstone, and in some 
places even into a loose white quartz sand. All gradations between 
bluish gray quartzite and white quartz sand are present in this quarry, 
the relative amounts of loose sand and friable sandstone being great- 
est nearest the surface where the leaching by surface waters has 
reached farthest into the sandstone from the joint planes. 

The following analysis gives the chemical composition of the bluish 
gray quartzite and the loose white quartz sand derived from it by 

Analyses of Quartzite and of Derived Sand. Westbrook Quarry. 

Huntingdon Oounty. 














Sand derived 
from quartzite 
by weathering. 





LiKikiTiB niirtLi^nst iii Ncirtli Qiinrry 

of Wostbnxik liliiHH Siimi Co., 

Mill t'm'k, I'vimn. 

-i— Oriihuny aa.idalonc 

McVeytown BlmwinR 


The analysis of the quartzite emphasizes the fact that no bond ex- 
cept silica is present between the grains. 

The change from bluish gray quartzite to friable white sandstone 
and loose sand seems to involve the solution of minute amounts of 
silica along the contacts between the individual grains of the rock, 
which gradually allows the \yater to work its way further and further 
into the quartzite and thus continue th^ disintegrating process. 
Quartz is ordinarily regarded as a mineral practically insoluble in 
water, but there seems to be considerable evidence that under certain 
conditions it does go into solution in small amounts. C. W. Hayes, M. 
L. Puller, and C. H. Smyth cites examples where pebbles and grains 
of quartz in conglomerates have been attacked and etched by atmos- 
pheric waters, not only at the surface but also along bedding planes 
In the interior portions of the rock.*^* Hayes and Fuller attribute 
this solvent action of the water to the presence of organic acids in 
it derived from decomposing vegetable matter. Smyth has observed 
this same action of atmospheric water on quartz pebbles under cer- 
tain conditions, but has not been Able to satisfactorily explain just 
what substance present in the water produced the effect. In the case 
of the weathering of the quartzite in the Westbrook quarry, just de- 
scribed, the evidence also seems to indicate that such a solvent action 
has occurred along the contacts between the quartz grains, and that 
this has reduced the quartzite to a friable sandstone, or even to a 
loose sand in places. Thin sections of the rock in question, when 
examined under the microscope, as well as chemical analyses, show 
that the only bond present is silica. 

It is a very difficult matter sometimes to explain just why the 
quartzite has become disintegrated sufficiently to be available for 
glass sand in one place while at another locality it appears as a hard 
vitreous quartzite practically at the surface. Several factors prob- 
ably determine this. One of these is the relative position of the 
outcrop with respect to the topographic features of the land, and an- 
other is the amount of fracturing which the rock has undergone. In 
central Pennsylvania the Oriskany sandstone occurs interbedded be- 
tween two layers of shale, which are comparatively impervious to the 
circulation of ground water. From observation made' over this area 
upon a large number of outcrops of the formation it was found that 
as a rule disintegration was-always most thorough where these were 
situated on the sides of the hills, so that the drainage down their 
slope would have to cross the sandstone outcrop, in other words an 
abundant supply of water to the outcrop appears to be a necessary 
requisite in producing thorough disintegration. Figure 1, Plate 

63. Bull. Geoloirlcal Society of America, rol. VTTT. 1896. pp. 218-220; Joar. of OedofT, Vol, 
X, 1902, pp. 815-821: Am. Jour, of Sden'** 4th. series, rol. XIX, 1905, pp. 277-285, 


LVIII, shows the position of the outcrop at the Granville mine of the 
Pennsylvania Glass Sand Company southeast of Lewistown, and 
Figure 2 that at the old Macklin mine at MeVeytown. In both cases 
the northwest dipping limb of the synclines, whose outcrops are situ- 
ated on the lower portions of the hillsides, have been thoroughly dis- 
integrated by circulating ground waters^ so that the sandstone crum> 
bles readily to a loose sand, while the southeast dipping limbs, form- 
ing the tops of the ridges at these places, are still hard white quartz- 
ite. A number of other similar occurrences were observed in Mif- 
flin county, some of which are referred to in a later chapter on the 
glass sand deposits of that county. Figure 1, Plate LIX, shows the 
position of the Oriskany outcrop on the northwest flanks of Jacks 
Mountain, just north of the North Quarry of the Keystone Works 
of the Pennsylvania Sand Company, northeast of Mapleton. The 
Oriskany outcrop in this vicinity forms a low ridge, known as Sand 
Ridge, on the northwest slope of Jacks Mountain, which is underlain 
by the hard, resistant Tuscarora quartzite. In places furthest away 
from the main streams flowing across the formations this low ridge 
disappears entirely, and there is only a slightly steeper escarpment 
along the northwest slope of Jacks Mountain and its northeast con- 
tinuation in Standing Stone Mountain, this depression from a geo- 
logic standpoint is usually one of the most recent of the topographic 
features developed, so that for a long time all along the greater part 
of Sand Ridge the drainage from the higher ridge to the Southeast 
flowed across it. This outcrop, therefore, in its relation to the surface 
topography is very much similar to the Granville and MeVeytown oc- 
currences, and it also has been sufficiently disintegrated along the 
greater portion of its length to be available for glass sand. Figure 
2, Plate LIX, shows a view looking northeast along Sand Ridge, from 
the Mapleton Quarry of the Pennsylvania Glass Sand Company. The 
Mapleton quarry in the Oriskany sandstone appears in the foreground 
at the left. The quarry back of it is in the Lewistown limestone 
which lies stratigraphically a short distance below the Oriskany 
sandstone. The Juniata river crosses the formation at nearly right 
angles between the two quarries. Jacks Mountain is the high ridge 
at the right, ' The bare white surface appearing in places on its 
flanks marks the outcrop of the Tuscarora quartzite. The valley 
between the Tuscarora and the Oriskany is deepest near the Juniata 
river and becomes less and less pronounced to the north until the next 
cross valley is approached. The town of Mapleton, on the south side 
of the Juniata river, appears to the right in the photograph. Quar 
ries are located at intervals all along the Oriskany outcrop in this 
vicinity, both north and south of the river. 
The position of the formation with respect to the surface to- 

l'l,ATK LX. 

< of OriMkiiiiv HiimlKtorii' mirtli '>r Ki'y- 
c Works <if I'l-iiiiKvlvniiin <:1iikh Sniid 
Co., Mniilctoii , I'd. 


pography, therefore, is one important factor which determines the 
amount of disintegration which it has undergone. The amount of 
fracturing which the quartzite underwent during the crustal move- 
ments in which the region has been involved is also important, as it is 
along these cracks that the water first gains access to the formation. 
The depth beneath the surface to which the disintegration has taken 
place depends upon the depth to which the water could circulate with 
relative ease. In the vicinity of Mapleton none of the quarries have 
been opened below the level of the Juniata river. At McVeytown, 
however, in the old Dull Mine, the sandstone was found to be well 
disintegrated to depths of 180 feet below the level of the river at that 
place. It is very likely, therefore, that both at McVeytown and 
Granville the bottoms of the synclines formed the lower channels of 
circulation, towards which the surface waters tended to flow, and that, 
therefore, the major portion of the northwest dipping limbs have been 

The whole of the quartzite has not always been sufficiently weath- 
ered to crush readily into loose sand. Often only a portion of the 
formation has been thus affected, so that in conducting quarrying 
operations it frequently becomes necessary to leave parts of the harder 
quartzite behind. At times a quarry may even have been abandoned 
because a poor location has been selected, where only a small portion 
of the exposed part of the formation has been disintegrated. This 
was found to be the case in the Westbroofe quarry, north of Mill Creek, 
in Huntingdon county. 

The rapidity with which the outcrop of the formation is being eroded 
is also an important factor in determining the amount of disinte- 
grated sandstone available. If this is situated in such a position 
that it is being worn away comparatively rapidly, the weathered 
sandstone may be removed practically as fast as it is formed, so that 
the outcrop will always consist of unaltered quartzite. 

There is usually a considerable contrast between the outcrop of . 
those portions of the Oriskany which have been disintegrated in the 
manner described above and the portions which are still quartzite. 
The latter are usually marked by sharp ledges, with angular edges, 
and an abundance of angular boulders strewing the surface in their 
vicinity, while in the case of the former considerable quantities of 
loose white sand are usually* found in their vicinity, especially on 
the lower portions of the slope. If ledges do crop out at the surface 
they have their edges rounded off and their joint planes or fractures, 
where disintegration has been most pronounced, have been deeply 
etched out by the destnictive forces of nature. 

Plate I»X shows the Oriskany outcrop just north of the North 
quarry of the Keystone Works of the Pennsylvania Glass Sand Com- 


pany; at Mapleton. Plate LXI, which is a nearer view of a smaller 
portion of the same outcrop, illustrates the rounded nature of the 
projecting ledge and the manner in which the joint planes have been 
etched out by erosion. Figures 1 and 2 of Plate LXIl, taken in the 
same vicinity also show this feature. At this place the Oriskany is 
a friable sandstone which can be readily crushed to loose sand. Where 
detached boulders occur along the outcrop these alsq, have their corn- 
ers rounded off. This difference in the appearance of the outcrops, 
therefore, can often be taken as a criterion in determining whether 
the formation underneath has been sufficiently disintegrated for glasB 
sand or not 

The picturesque pulpit rocks on Warriors Ridge, west of Hunting- 
don, along the Huntingdon-Alexandria road, shown in Figure 3, Plate 
LXII, and in Plate LXIII, are another example of this differential 
weathering. The Oriskany beds at this locality lie almost horizontal, 
while the joint planes are nearly vertical. Much of the sandstone 
here has weathered to a loose sand, unfortunately, however, too high 
in iron to be available for a first class glass sand. The pulpit rocks 
simply represent erosion lemnants of the least weathered portions of 
the formation. They consist of more or less isolated pillars of sand- 
stone, formed by the washing out of the loose disintegrated rock along 
the vertical joint planes, and to a less extent along certain of the 
bedding planes. They rise to heights of about fifty feet in places. 
Even the sandstone of which they are composed has been disinte- 
grated sufficiently that it can be readily crushed to a loose, light 
brown sand between the fingers. 

Practically the only deleterious impurity which is apt to occur in 
sands derived from Oriskany formation in central Pennsylvania is 
iron, in the fonn of limonite. This may come from two sources. 
Iron oxides, or occasionally such a mineral as hornblende, may have 
been present in sufficient amounts in the original sandstone that the 
sand derived from it will have too high an iron content to be suit- 
able for glass sand, or the waters which later penetrated the sand- 
stone and brought about its disintegration may have had iron in so- 
lution which they deposited as a thin film around the grains of quartz. 
The sandstone for some distance on either side of joint planes, along 
which such waters penetrated the rock, are frequently found to be 
stained brown by limonite deposited in this manner. Figure 2, 
Plate LV shows a thin section of such a sandstone with thin films 
of limonite deposited around the quartz grains, as it appears under 
the microscope. This section also shows that the percolating waters 
enter the sandstone along the contacts between the individual grains, 
as it was along these that the limonite was deposited. Occasionally 


Near view of OriKkniiy outcmii north of Kpj- 

Gtouc \Vork», IVniixylviiiiin CInss Sand 

Co., MaplL'ton, Pa. 


also a little occurs along minute cracks in the grains themselves, where 
the iron bearing solution had access to thenu 

At the outcrop the outer few inches of rock are frequently stained 
a yellowish brown or grayish brown by small amounts of organic 
matter and limonite, while further down the rock turns into a white 
friable sandstone. This phenomenon was observed at many localities 
along Sand Ridge in the vicinity of Mapleton. An anaylsis of rock 
stained in this manner, taken from the outcrop at the Keystone works 
of the Pennsylvania Glass Sand Company, showed J2^ % FejO,, while 
the white sand rock quarried at this place has the following compo- 

Analysis of White Sand Rock at Keystone Works. 

SiO,. 99.76 

Al.Oa - 14 

Fe.O. - .07 

MgO, — none 

CaO .28 

H.O 09 

TiO,. — 02 

Total 100.36 

From the above discussion it is seen that the Oriskany formation 
of central Pennsylvania yields glass sands only in those places where 
the deposits consisted originally of practically pure quartz sands, 
which later become quartzites, and were then exposed to conditions 
favorable for weathering without access of iron bearing solutions. 
Under these circumstances friable sandstones or loose sands have re- 
sulted, which yield some of the highest grade glass sands produced 
in this country or abroad. 

Preparation ol the Sand for the Market. 

At the present time, with the exception of the Granville Mine of 
the Pennsylvania Glass Sand Company southwest of Lewistown, in 
Mifflin county, and small sand mine operated by John Miller near 
Bumham, a suburb of Lewistown, all of the Oriskany sandstone mined 
for glass sand is taken out in open quarries. At Granville under- 
ground mining operations are carried on, which are described in a 
later chapter on the glass sand deposits of Mifflin county. In the 
open quarries the sand rock is blasted down, loaded onto cars and 
taken to washing plants, where it is crushed, dried and screened. 

The methods used in preparing the sand for market by the large, 
operators in central Pennsylvania are about the same throughout 
the region. Practically all of them wash and dry their sand* The 
sandstone as it comes from the quarry is first passed over a grizzly, 
consisting of a series of parallel steel bars, placed about two inches 
apart, on an incline. The fine material drops through the slots be- 
tween the bars, while the larger pieces pass over into a jaw crusher. 
The material from the jaw crusher, and that which passed through 


the grizzly, then goes directly to a chaser mill or wet grinding pan, 
which crushes the sandstone to sand. The crushed material next 
goes through a revolving screen, with from 10 to 12 meshes per linear 
inch. This separates the sand from uncrushed fragments of sand- 
stone, which are returned to the grinding pan. The sand passes 
on to a battery of screw washers, where it is washed as free as pos- 
sible from clayey material and limonite. It is then piled up in large 
cone shaped heaps and allowed to drain for about twelve hours be- 
fore it is dried. Several types of dryers are employed, among 
which the steam dryer is the most common. After it has been dried, 
the sand is again screened and either loaded into cars or stored in 
bins for later shipment. 

The above methods for crushing, washing, drying, and screening 
the sand have already been described in detail in Chapter V, under 
the head of "Silica as a raw material for the manufacture of glass.'' 
The equipment of the different plants operating in central Pennsyl- 
vania, and minor variations in the methods practiced in preparing 
the sand, are discussed in later chapters dealing with the individual 
properties. In some cases the sandstone has been sufficiently disin- 
tegrated by weathering that jaw crushers and chaser mills are not 
required and the sand is waited directly as it comes from the mine or 

Usually the sandstone is roughly sorted into different grades in 
the quarry on the basis of the amount of iron stain or limonite which 
it shows. Only the purest portions of the rock are used for what is 
called Number 1 sand. In addition to this two other grades, namely 
numbers 2 and 3, are usually made which contain more iron. These 
cannot be used in the manufacture of the better grades of glass, but 
are available for window glass, bottle glass, etc. 

Examination of Undeveloped Areas. 

In determining whether a certain outcrop of Oriskany sandstone 
has any value as a possible source of glass sand, the first two things 
to investigate are whether the rock is sufficiently pure and whether 
it has undergone the requisite amount of disintegration by weather- 
ing to cause it to crumble comparatively readily into loose sand when 
.put through the chaser mill. Often it is very difficult or even impos- 
sible to do this from the mere outcrop and some exploratory work 
is necessary to open up the deposit sufficiently to enable one to see 
the true nature of the rock. If small particles of the rock can be 
crumbled into loose sand between the fingers, the rock is sufficiently 

Attention has already been called to the fact that one can often 
obtain a pretty good idea of the nature of the sandstone from the ap- 


pearance of its outcrop. If there are many projecting ledges, with 
sharp edges, and the surface over the outcrop is strewn with angu- 
lar holders, one is pretty safe in concluding that the underlying for- 
mation is a quartzite too hard to be economically crushed for glass 
sand. On the other hand if the outcrop is marked by the presence 
of considerable quantities of white sand and the projecting ledges 
have had their cornel's rounded off and their joint planes etched out 
as already described in a previous paragraph, and loose boulders of 
the rock overlying the outcrop are rounded instead of angular, the 
formation underneath, as a rule, has undergone the requisite amount 
of disintegration to cause it to become crushed readily into sand. 
Occasionally the outer few inches of rock next to the surface may 
be stained a grayish or yellowish brown, while the rock itself, when 
broken intO; is found to be white and practically free from iron oxidea 
This must also be kept in mind when examining outcrops. 

The position of the outcrop with respect to the topography of the 
surface, and the inclination of the beds from the horizontal are also 
important factors that determine the relative value of a particular 
occurrence of the sandstone. Upon these factors the drainage of 
the quarry and the amount of overburden that will have to be re- 
moved largely depend. A particular deposit of sandstone often 
cannot be economically worked because these conditions are not favor- 
able. Sometimes the sandstone occurs in such a position that it 
can only be worked by carrying on underground mining operations. 
This increases the cost of production considerably and the rock must, 
therefore, be exceptionally pure and well disintegrated to make such 
an undertaking profitable. 

The location of the deposit with respect to transportation facilities 
is another factor to be taken into consideration. Sand is a bulky 
material, produced with only a small margin of profit. CJonvenient 
and cheap transportation facilities to good markets are therefore, 
highly essential. An adequate water supply for washing the sand 
must also be available in the vicinity of the deposit. 

Even after the above conditions have all been found to be favorable 
some exploratory work should be done on the deposit before any ex- 
tensive plant for preparing the sand for the market is erected. If 
the outcrop is badly covered with overburden some of this should be 
removed and either bore holes with core drills, cross cuts, or shafts, 
should be made at intenals sufficiently close to give one an idea of 
the thickness and nature of the sandstone over an area sufficiently 
large to warrant the erection of the necessary plant for treating it. 
Ck)nsiderable sums of money have often been wasted by erecting 
plants at deposits where outcrop indications alone were taken into 
consideration, which on further development proved misleading. 


Distribution of Workable Deposits in Pennsylvania. 

In Pennsylvania the Oriskany sandstone is being extensively quar- 
ried for glass sand in the vicinity of Mapleton in Huntingdon county 
and at Vineyard and Granville, in Mifflin county. These three places 
are at present the great centers for the glass sand industry in cen- 
tral Pennsylvania. Deposits of sufficient purity to be available for 
first class sand also occur in the vicinity of Everett, in Bedford 
county, but have not as yet been exploited for this purpose. At a 
number of other localities in central Pennsylvania, outside of the 
above areas, small quantities of Oriskany sandstone have been quar- 
ried for glass sand, but these have only been used in the manufacture 
of the cheaper grades of glass, such as bottle glass. 

In describing the deposits of central Pennsylvania, those of Hunt- 
ingdon and Mifflin couties are taken up in detail first, and then the 
other occurrences are referred to briefly. 




' /. 

Tus^e^ Ml: 



Warrior Ridqe. 






' -i 



2. t^ 
3 r 

£ < 






\ N 







5ond Ridqe 



JqcKs fV/t. 

Che3ir}ui Ridqe 





Location of Outcrops. 

In Huntingdon county formatipns ranging from Ordovician through 
Pennsylvania age are exposed at the surface. This is due to the 
fact that the strata are involved in the Appalachian folding, which, 
as has already been stated, occurred towards the close of the Per- 
mian period. Plate LXIV is a cross section showing the structure 
of the formations underlying Huntingdon county. By the erosion 
of the arches or anticlines, formed by this folding, strata as low as 
the Ordovivlan have been brought to the surface, whDe in the trough 
or syncline between two anticlines in the southwestern portion of the 
county Pennsylvanian strata have been preserved to the present day. 
The coal deposits of the Broad Top Mountain area occur in these 
Pennsylvanian beds. The axes of the anticlines and synclines fol- 
low a northeasterly and southwesterly direction, with a southwest 
pitclL Therefore, the outcrops of the various formations follow a 
similar course. 

In Huntingdon county the Tuscarora sandstone or quartzite of 
lower Silurian age, the so-called Medina sandstone of the Second 
Geological Survey of Pennsylvania, is the formation which is the 
most resistant to erosion. It is the mountain or ridge forming for- 
mation of central Pennsylvania ; Tuscarora, Shade, Black Log, Jacks, 
Standing Stone, and Tussey Mountains marking its outcrops in Hunt- 
ingdon county. At Mt. Union, Mapleton, and Three Springs, this 
massive white quartzite is extensively quarried as ganister for the 
manufacture of silica brick. 

The Oriskany formation of the lower Devonian is also represented 
by a quartzite varying from white to bluish gray in color, but it is 
not as resistant to weathering as the Tuscarora, nor does it have the 
great thickness of the latter. For this reason, although the out- 
crops of the Oriskany are also usually marked by ridges, these are 
insignificant in height when compared with those formed by the Tus- 
carora. Very often they occur as minor ridges on the flanks of the 

In Huntingdon county the Oriskany occurs in the syncline between 
Tuscarora and Shade Mountains in the southeastern part of the 
county. Its outcrop here forms two narrow belts, one on the west 
side of the Tuscarora and the other on the east side of Shade moun- 
tain. In the syncline itself it is buried under Devonian shalr 


Similarly it occurs in the syncline between Black Log and Jacks 
Mountain, with outcrops on the west side of Black Log and on the 
east side of Jacks Mountain. North of Shirleysburg several minor 
flexures in this syncline bring the Oriskany strata to the surface 
several times. The outcrop on the east side of Jacks Mountain 
forms Chestnut ridge. It runs in a northeast and southwest direc- 
tion through Mount Union. The Oriskany formation also occurs 
in the broad syncline between Jackyand Tussey Mountains. Here 
it is covered not only by middle and upper Devonian shales and sand- 
stones, but also by Mississippian and Pennsylvanian strata. nie 
outcrop on the west side of Jacks Mountain in the vicinity of Maple- 
ton is known as 8and Ridge. This outcrop joins with that of Chest- 
nut Ridge around the southside of Jacks Mountain, on aceonnt of the 
southwest pitch of the Jacks Mountain anticline, and on the north- 
west with that along the west side of Tussey Mountain on account of 
the similar pitch of the syncline. This last outcrop forms Warrior 
Ridge in the vicinity of Huntingdon. Plate LXV is a map showing 
the distribution of the Oriskany outcrops in Huntingdon, Miffliin and 
Bedford counties. 

Workable Portions of the Oriskany. 

From the standpoint of economic value as a source of glass sand 
the outcrop of Oriskany which forms Sand Ridge is by far the most im- 
portant in the county. This is the source of the glass sands quarried 
so extensively in the vicinity of Mapleton. The sands of Warriors 
Ridge have also attracted some attention as possibly being of value 
for the manufacture of glass, but no very extensive industry has as 
yet been developed along this ridge. For the location of places men- 
tioned in the following description, reference should be made to Plate 
LXV and to Plate LXVI, which shows the location of the sand quar^ 
ries around Mapleton. 

Sand Ridge, as has already been stated, forms a low ridge along 
the west side of Jacks Mountain, which north of Mill Creek, (where 
Jacks Mountain divides into two ridges, the easterly one of which 
is still known as Jacks Mountain, while the westerly one goes under 
the name of Standing Stone Mountain), continues along the west side 
of Standing Stone Mountain until, in the northern part of the county, 
it swings to the west and joins Warriors Ridge northwest of Hunt- 

At Mapleton a gap occurs in the ridge, as well as in Jacks Mountain, 
where the Juniata river crosses the formation at right angles. South 
of the river there is a small valley occupied by Scrub run, between 
Sand Ridge and Jacks Mountain. TUs valley has been eroded in 
the softer limestones and shales of the Lower Devonian and the 





Map showing Oriskj 

Map sho\ 





/;*> WesfbrooK 
/^^* 6 la sb band Co, 

'iV Creek. 


^y!^/^bandonedfTonKlin Quarry 
'<v Columbia Quarries. 


//> Ke>*5fohe/0uarned. 
'Iv^ /\bondone^ Empire Ouorri« 

ed Quarry, 


.^"^ Junfoio White 5cindCor 
>j^^Pctt5bur^h White 5ond Co. 



• ^* 



tion of glass sand qiiarrios in vicinity of Maploton. 


Silurian which occur between the Oriskany and Tuscarora formations. 
Further south this valley disappears and the Oriskany forms a low 
ridge on the flanks of Jacks Mountain. In places this ridge disap- 
pears entirely, although the outcrop of the Oriskany is usually marked 
by a rather steep cliff or escarpment on the west side. On the north 
side of the river similar conditions exist. 

South of the Juniata Biver Sand ridge appears in the form of a 
low ridge in the town of Mapleton and gradually rises to a high, steep 
ridge to the southward. The nature of the rock comprising the ridge 
may first be studied to advantage in an old abandoned quarry on 
the southern margin of the town. Here the ridge has an elevation of 
about 130 feet above the surrounding country. The sandstone for- 
mation strikes N. 25°E, and dips 65^ to the northwest. It has un- 
dergone considerable fracturing so that joint planes are prominent. 
One set is nearly parallel to the bedding plane, another is parallel to 
the strike and nearly vertical, while a third occurs at nearly right 
angles to the strike and is steeply inclined. Other sets are also 
present but are less prominent. These fractures or joints have given 
access to downward percolating rain water, which has produced ex- 
tensive disintegration in the sandstone. Soil is almost entirely ab- 
sent from the top of the ridge and erosion has therefore etched out 
these joint planes, so that the outcrop is marked by a series of fan- 
tastic shaped forms, similar to those illustrated in other portions of 
this report. 

The rock is somewhat less disintegrated than that of some of the 
other quarries at present operated around Mapleton. The sharp 
edges are still retained by the angular blocks left in the quarry face, 
although it has not been operated for^many years as is shown by the 
size of the trees growing in it. When small pieces of the rock, how- 
ever, are taken between the fingers they can be broken down into loose 
sand. A little iron oxide has been deposited in the form of limonite 
along some of the joints by percolating waters, and here and there 
little yellow specks of limonite occur in the main body of the rock it- 
self. Otherwise it is a pure quartz sand^one which can be quite 
readily crushed down to a light cream colored sand. 

A short distance south of the above quarry, along the ridge, is the 
quarry of the Mapleton works of the Pennsylvania Olass Sand Com- 
pany. At the north end of the quarry the ridge rises about 120 feet 
above the level of Scrub run at this place, while at the south end it 
rises to an elevation of 165 feet. The floor of the quarry is about 
50 feet above the level of the run. The formation has a strike of N 
29® E, and dips 53® to the northwest. It has a thickness of 168 feet. 
At about the middle of the north end of the quarry a bed of conglom- 
erate three feet in thickness is present. Some of the pebbles, which 


consist entirely of quartz, have a diameter of i inch, but most of 
them are smaller. The conglomerate is very fossiliferous. Twelve 
hundred feet south, at the other end of the quarry, it has a thickness 
of only one foot. Small pebbles are also present occasionally at 
other horizons in the formation at this quarry, especially in the upper 

The sandstone at this place has also undergone considerable frac- 
turing. A moderate amount of iron oxide in the form of limonite 
has been bit)ught in along some of the joint planes. In some cases, 
where the fracturing has been very intense, this limonite has pene- 
trated the rock itself. In a^ew places a little black oxide of man- 
ganese in the form of dendritic growths has also been deposited along 
some of the joints. Portions of the rock show little rust spots con- 
sisting of limonite scattered here and there through the mass. These 
have evidently resulted from the weathering of some mineral in the 
rock which contain iron. Outside of this the rock is a pure white 
quartz sandstone. 

On the whole, the rock has undergone considerable weathering, so 
that most of it can be readily disintegrated into loose sand between 
the fingers. There are portions of it, however, which have escaped 
this weathering process. These are still hard, a white to buflf col- 
ored quartzite, and when encountered in considerable masses in the 
quarry have been left behind while the softer rock around them was 

The Mapleton quarry of the Pennsylvania Glass Sand (Company is 
adjoined on the south by the North quarry of the Pittsburgh White 
Sand Company. At this place the Oriskany sandstone has been 
quarried for a distance of nearly 2000 feet along the strike. The 
highest ledges along the crest of Sand Ridge rise about 160 feet above 
the level of the present quarry floor. The formation dips 65i® to 
the northwest and has an approximate thickness of 130 feet, of which 
the lower 90 are being quarried at the present working face. Plate 
LVI shows the appearance of this face. The rock has been con- 
siderably fractured. One set of joints is practically parallel to the 
bedding plane, while another set has a strike of N 69® E and dips 
69** to the northwest. Most of the sandstone crumbles readily to 
loose white sand. A screen analysis of a series of samples taken 
across the sandstone gave the following results: 


Screen Inalysis of Sand from North Quarry, Pittsburgh White Sand Co. 

Through 4 mesh, on 6 mesh (.131 inches diameter) 42% 

Through 6 mesh, on 8 mesh (.093 inches diameter) 73% 

Through 8 mesh, on 10 mesh <. 065 inches diameter), 1.73% 

Through 10 mesh, on 14 mesh (.046 inches diameter), 1.57% 

Through 14 mesh, on 20 mesh (.0328 inches diameter) 2.42% 

Through 20 mesh, on 28 mesh (.0232 inches diameter), 7.36% 

Through 28 mesh, on 35 mesh (.0164 inches diameter), 18.90% 

Through 35 mesh, on 48 meah (.0116 inches diameter), 47.84% 

Through 48 mesh, on 65 mesh (.0082 inches diameter) 14.71% 

Through 65 mesh, on 100 mesh (.0058 inches diameter) 2.18% 

Through 100 mesh, on 150 mesh (.0041 inches diameter). .48% 

Through 150 mesh, on 200 mesh (.0029 inches diameter) 37% • 

Through 200, — 42% 


In the northeast corner of the quarry, where it adjoins the Penn 
sylvania Glass Sand Company's property, the lower portion of the 
formation is somewhat harder and can only be disintegrated with 
difficulty between the lingers. It consists of white sandstone, with 
occasional specks of Umonite. Under the microscope it is seen to 
consist of an interlocking mosaic of angular quartz grains, some of 
which from the distribution of inclusions in them, appear to have 
been originally rounded. Some of the quartz grains show undu- 
latory extinction between crossed nicols. Many of them contain 
minute dust like inclusions, while in others rutile needles and minute 
prismatic crystals of apatite are visible. One well rounded grain 
of hornblende was observed. The occasional specks of limonite in 
the sandstone are probably due to the weathering of scattered grains 
of this mineral in the rock. 

Between one-third and one-half mile further south along Sand Ridge 
is the quarry of the Juniata White Sand Company. This quarry 
has been opened for a distance of 300 feet along the strike. The 
formation dips 63° to the northwest and the sandstone has a thickness 
of about 150 feet. The surface of the highest sandstone outcrop 
along the top of the ridge rises 160 feet above the level of the quarry 
floor. The most prominent set of joints is parallel to the beddiug 
plane. The cross joints have a strike of N 42° E and dip 70° N. W. 
The sandstone is white in color, except where it has occasionally been 
stained brown for several inches on either side of a joint plane by 
infiltenng iron bearing solutions which have precipitated limonite 
between the quartz grains. Here and there portions of the sand- 
stone have scattered through them minute specks of limonite. A 
thin section of such a specimen under the microscope showed one 
well rounded grain of hornblende to be present which seems to point 
to this, mineral as being responsible for the brown spots disseminated 
through the rock, since limonite is one of the alteration products of 
hornblende when the latter undergoes weathering. The hardest rock 
present in this quarry can only be disintegrated with difficulty into 


sand between the fingers. Much of the rock however^ crumbles 
readily into white sand. 

About one-quarter mile south of this quarry, along Sand ridge, the 
Pittsbui^h White Sand Company is opening up a new quarry. At 
the time of the writer's visit in 1914 no very great thickness of sand- 
stone had yet been opened by the quarrying operations, which were 
still confined to the upper portions of the formation. The sandstone 
i% somewhat harder than that exposed in the other quarries along 
Sand Ridge, south of Mapleton, it being possible to crush only small 
fragments of it with diflSculty between the fingers. The sandstone is 
white in color, except where it has been occasionally stained by a 
little limonite along a plane of fracture. 

The South quarry of the Pittsburgh White Sand Company is the 
last opening in the Oriskany sandstone of Sand Ridge south of Maple- 
ton. The outcrop continues in a southwesterly direction beyond 
Saltillo, which is about 12 miles from Mapleton, where it swings 
around the southern end of Jacks Mountain and becomes Chestnut 
Ridge along the east side of the latter. Beyond the South quarry 
of the Pittsburgh ^Vhite Sand Company Sand Ridge begins to stand 
out less prominently, due to the gradual disappearance of the valley 
between the outcrops of the Oriskany sandstone and the Tuscarora 
quartzite of Jacks Mountain. In places the Jacks Mountain slope 
continues uninterrupted across the Oriskany outcrop to Hare's Valley. 
Usually, however, even in these cases, there is a little steeper slope 
on the west side, or down hill side, of the Oriskany outcrop. 

As a rule the outcrops of sandstone are not as prominent as they are 
further to the north in the vicinity of Mapleton. Rounded boulders 
occur along the outcrop and here and there masses of the sandstone 
which are in placa From their appearance they indicate that the 
underlying formation is probably well disintegrated Tby weathering. 
The position of the outcrop on the west slope of Jacks Mountain in- 
sures a good supply of surface drainage, much of which has an oppor- 
tunity to penetrate the sandstone formation, making conditions ideal 
for its disintegration to a suflScient degree to make it available for 
glass sand. Pieces of the sandstone chipped from surface boulders 
and projecting masses of the sandstone, usually have a brown or 
brownish gray color, due to stain by limonite and organic matter. 
This cannot be taken as indicating that the underlying rock contains 
too high an iron content to yield a good glass sand, however, because, 
as has already been stated, the outcrops of some of the best sand rock 
north of Mapleton have the same appearance. The true nature of 
the rock can only be determined by carrying on some exploratory 
^'ork beneath the surface. 



Fig. 1. Cross section of Sand Riflgc one quarter mile south of South Quarry 
of PittKburgh White Sand Company, Mapleton. 

Fig. 2. Cross section of Sand Ridge three miles north of Saltillo. 


About one-quarter mile south of the Bouth Quarry of the Pittsburgh 
White Sand Company the profile shown in Figure 1, Plate LXVII 
was made to show the position of the Oriskany sandstone with respect 
to the sui'face topography. The sandstone ha« a thickness of 170 
feet at this place. The ralley between it and the Tuscarora quartz- 
ite of Jacks Mountain has practically disappeared. One disadvant- 
age in conducting quarrying operations here would be the compara- 
tively large amount of overburden which would have to be r^noved 
from the hanging wall before operations could proceed. The forma- 
tion dips 67° to the northwest. Indications upon the surface are 
that the sandstone underneath is sufficiently friable for crushing into 
glass sand. 

About 5^ miles southwest of Mapleton, just south of the place 
where the road through Singers Gap crosses Jacks Mountain, Sand 
Ridge is again marked by a rather rugged outcrop, similar to that in 
te vicinity of Mapleton, with many isolated pinnacles of sandstone 
projecting above the main mass. The beds dip 55° to the northwest, 
and about 110 feet of sandstone are exposed. The tipper portion of 
the fonnation contains some pebbles up to one-quarter inch in 
diameter. The lower portion is free from these. All of the outcrop 
rock can be crushed into sand between the fingers. It usually has a 
brown color when chipped off from the surface. Occasionally some 
limonite occurs along fractures in the rock, but as a rule this does 
not penetrate the sandstone itself. Surface indications at this 
place are favorable, but, as has already been mentioned in other cases, 
some exploratory work is necessary before any positive statement as 
to the value of the sandstone for glass sand can be made. 

About three miles north of Saltillo the formation has a thickness 
of about 110 feet, and dips 60° to the northwest. It has been pretty 
well disintegrated, judging from outcrop indications. The project- 
ing ledges and loose boulders are well rounded and considerable white 
sand lies about on the surface. Figure 2, Plate LXVII, shows the 
position of the outcrop with respect to the surface. Prominent ledges 
of sandstone occur along the hanging and foot walls, with very little 
rock exposed between. This indicates that the middle portion of the 
formation has probably been more thorovyp^hly weathered than the 
upper and lower. From outcrop indications the formation at this 
place, with the exc^ion of a few feet of the lower portion, is com- 
paratively free from iron. 

To the south of the above outcrop the formation looks less promis- 
ing as a possible source of glass sand. Where the Hare's Valley road 
crosses the outcrop, about one-half mile north of Saltillo, there is a 
small opening on the formation on the north side of the road. The 
sand exposed is v^ry argillaceous and the boulders of sandstone in 


it do not appear promising on account of their high limonite content. 
Only talus material, however, has been penetrated. 

In the vicinity of Baltillo the Oriskany sandstone forms a distinct 
ridge separated from Jacks Mountain by a wide valley, the former 
lying to the west while the latter lies to the east of the town. In 
places along the former the sandstone has been weathered to a loose 
sand, but in" other places it is still a hard quartzite, judging from 
the surface boulders occasionally seen along the outcrop. Where 
it has weathered to a sand this is stained light yellowish brown by 
limonite, and in places contains considerable clayey material. It 
would not yield a first class glass sand even on washing. 

North of Mapleton, Sand Ridge stands out very prominently, rising 
to a height of from 180 to 260 feet above the river, with a steep escarp- 
ment along the northwest side. The appearance of the ridge here is 
well shown in Plate LXVIII, which is a view taken at the quarries 
of the Keystone works of the Pennsylvania Glass Sand CJompany north 
of Mapleton, looking east. The valley between the Oriskany sand- 
stone outcrop of the Sand ridge and the Tusarora quartzite of Jacks 
Mountain is only pronounced where valleys have been cut at right 
angles by streams through Sand Ridge and developed tributaries par- 
allel to the strike of the formations in the softer shales and limestones 
between the two sandstones. The profile of the ridge shown in Figure 
1, Plate LIX, was made a short distance to the left of the quarry 
appearing near the center of the picture in Plate LXVIII. 

The first quarry along Sand Ridge north of Mapleton is situated at 
the point where the Oriskany sandstone outcrop again rises as a ridge 
north of the gap formed by the Juniata river. The formation here 
dips 61** to the northwest and is fossilferous throughout its entire 
thickness. Underneath it a fossilferous sandy shale is exposed. 
Fracturing is pronounced, the most prominent set being very nearly 
parallel to the bedding planes. The sandstone here is comparatively 
hard, only small portions of it crumbling readily into sand between 
the fingers. Most of it is white to light cream yellow in color, with 
occasional portions showing scattered specks of limonite. 

Adjoining this quarry on the north is the South quarry of the E3m- 
pire works of the Pennsylvania Glass Sand Company. This plant 
has been dismantled and the quarry, therefore, is not being operated 
at present. The sandstone at this place dips about 58® to the north- 
west, and has an approximate thickness of 130 feet, of which the up- 
per half was quarried. The sandstone on the whole is white in color, 
except where occasionally a little limonite stain occurs in it along a 
joint plane. About one-third of it crumbles readily to sand in the 
hand, while the rest can be crushed between the fingers when small 
fragments are broken off. About 500 feet beyond is the North quarry 

ivr>sLujie %% orKH or I'ennNyivunia uiass 
CV, at Maploton, Pa. 



of the same works, also abandoned at present. Here the sandstone 
dips GS'^to the northwest, and has an approximate thickness of 125 
feet, of which the upper 70 feet were quarried. This quarry has 
been opened for a distance of 280 feet along the strike. The ridgt 
rises to an elevation of from 180 to 200 feet above the level of the 
Juniata river. The sandstone here has a white color and can be 
crushed to sand between the fingers. Along some of the fracture 
planes disintegration to loose sand has occurred, which usually has a 
light cream yellow color due to the infiltration along the joints of 
small amounts of iron in solution. 

About 700 feet north of this opening is the South Quarry of the 
Keystone Works of the Pennsylvania Glass Sand Company. This 
quarry, at the time of the writer's visit in 1914, had a length of 
about 300 feet, along which the upper 80 feet of sandstone had 
been quarried for glass sand. The rock is of an excellent quality, 
only moderately hard and pure white in color. Very little iron stain 
occurs along the joint planes. The following analysis shows the 
chemical composition: 

Analysis of Glass Sand from Sonth Quarry* Keystone Works, Mapleton, Pa. 

SlOg - 99.76 

v^ AliOs. .14 

FegOa 07 

MgO. — - - none 

CaO , - 28 

H,0» — .09 

TiO, - 02 


The North Quarry of the Keystone Works is 300 feet further on 
along the ridge. It has been opened for a distance of 690 feet along 
the strike. The formation has a thickness of about 130 feet. In one 
place the foot wall has been broken through and a large amount of 
shale has run into the quarry, causing considerable inconvenience. 
The quality of the rock is the same as that taken out in the South 
Quarry. At the southwest end a streak of cream colored sand was 
encountered near the foot wall. The two quarries are shown in 
Plate LXVIII, the North Quarry being the one near the center of 
the photograph, while the south one is at the right. The sandstone 
runs up to the top of the ridge, which rises about 240 feet above the 
level of the Juniata River flood plain shown in the foreground. Fig- 
ure 1, Plate LIX, shows a cross section of the ridge made about 250 
feet to the left of the center quarry. Plate LXIX shows the api)ear- 
ance of a portion of the northeast workiug face of this quarry at the 
time of the writer's visit. 

The next opening along Sand Ridge is the South Quarry of the 
Columbia Works of the Pennsylvania Glass Sand Company, situated 
about one and two-thirds miles northeast of Mapleton. This quarry 



in located on the north side of a small cre^ which has cut a valley 
across Sand Bidge at this place. Figure 1, Plate LXX shows a view 
of the quarry looking northeast along the strike. The Oriskany for- 
mation here dips 62° to the northwest and has a thickness of about 
200 feet. The top of the ridge rises 110 feet above the floor of the 
quarry. The sandstone here is also pure white in color but some- 
what harder than that encountered at the Keystone quarries. Most 
of it cannot be crushed to sand between the Angers, It is badly frac- 
tured as the view of the quarry shows. 

About 700 feet north of this quarry the Pennsylvania Glass Sand 
Company has recently opened up another quarry to supply the Co- 
lumbia Works with sandstone. At the time of the writer's visit only 
the upper portion of the sandstone had been exposed. The rock is 
also white in color and is more friable than that encountered at the 
South Quarry. Much of it can be readily crushed between the fingers. 

Less than one-quarter mile northeast of the Columbia Works, on 
the south side of another small creek which has cut a valley across 
Sand Bidge, is located the Franklin quarry of the Pennsylvania Glass 
Sand Company. The mill which was supplied with sandstone from 
this quarry was dismantled a number of years ago and the quarry 
is, therefore, not operated at present. Figure 2, Plate LXX, shows 
a view looking southwest along the strike in this quarry. The sand- 
stone has a thickness of 120 feet and dips 62° to the northwest. The 
lower few feet and the upper portion of the formation are quite hard 
and were left behind, only the lower 65 feet being quarried. This 
part is fairly friable and crumbles readily to sand. The rock is 
white in color. About 500 feet of the formation have been removed 
along the strike. The ridge rises about 150 feet above the floor of 
the quarry and on top is fairly level, forming a terrace on the west 
slope of Standing Stone Mountain. 

Continuing northeast along Sand Bidge another valley cuts across 
it east of the town of Mill Creek. On the north side of this valley 
the Westbrook Glass Sand Company opened a quarry, which was 
abandoned when its plant at Mill Creek was dismantled. The sand- 
stone at this place has a thickness of about 125 feet, and dips 65° to 
the northwest. Most of the rock exposed in this quarry consists of 
a bluish grey quartzite, too hard to be economically crushed to glass 
sand. Where slight leaching has occurred along fractures it has been 
turned white in color, but it is still a quartzite. 

About 4,000 feet northeast of this locality the Westbrook Glass Sand 
Company opened another quarry along Sand Bidge. Conditions en- 
countered at this quarry have already been described in Chapter XV, 
under the head of secondary changes necessary in the Oriskany sand- 
stone to render it suitable for glass sand. Figure 1, Plate LVII, 


'i>liimbiti Wrirks nf 

t : 



shows a cross section of the quarry and figure 2 is a view taken in the 
quarry. The formation also has a thickness of about 125 feet at this 
place and dips 60° to the northwest. Leaching has only proceeded to 
a depth of from 25 to 30 feet beyond the exposed surface of the sand- 
stone. When this was removed along the face of the cliff formed by 
the outcrop a white to bluish gray quartzite was encountered which 
has already been described. The ridge rises to an elevation of about 
225 feet above the floor of the quarry which was opened up for a 
distance of 200 feet along the strike. The following two analyses 
give the composition of the qimrtzite and the white sand derived from 
it by weathering: 

Analyses of Quartzite and Sand from Near Mill Creek. 

Sand derived 
from quartzite 
by weathering. 

SiOa - 

AhOa — . 


MgO -. 


Total _ 




A careful examination of the outcrop at this locality with those 
features in mind which indicate considerable disintegration of the 
underlying rock would have shawn that the rock would very likely be 
too hard for economically crushing into glass sand. Such an investi- 
gation would have saved a considerable sum of money spent in the 
erection of a plant, which later had to be abandoned. The outcrop 
is marked by prominent ledges cropping out at the surface. Joint 
planes are not deeply nor widely etched out. . Along the top of the 
ridge large masses of loose boulders occur, many of which are quite 
angular, although some are partially rounded. Along the steep 
cliflP on the west side, where very little soil is present, the rock is 
sometimes a quartzite at the surface. 

About one mile northeast of the Westbrook Quarry, Saddler Run 
has cut a wide gap in Sand Ridge. South of the gap the ridge rises 
sharply, with steep slopes on either side. No prominent pinnacles of 
Oriskany sandstone project, however, the outcrop being simply marked 
by more or less isolated boulders. Some of these are almost white in 
color, but most of them are stained a light yellowish brown or gray- 
ish brown by limonite and organic material. Chips from these 
boulders can be cnished to sand in the hand. 

North of the Saddlers Run gap, Sand Ridge again rises to an ele- 
vation of 235 feet above the level of the run and continues along the 


northwest slope of Standing Stone Mountain^ in some places as a sepa- 
rate ridge on the slope of the latter, while in other places merely as 
a somewhat steeper escarpment on the west side, near its base. At a 
number of places where the outcrop was examined by the writer it 
looks favorable as a possible source of glass sand, but no definite state- 
ment can be made without some preliminary exploratory work. Fig- 
ure 1, Plate LXXl, shows a profile of the ridge made about 3i miles 
north of Mill Creek. The foimation dips 60° to the northwest at this 
place and about 80 feet of sandstone are exposed. The outcrop is 
very prominent, there being many isolated pinnacles projecting along 
the ridge. Some of the outcrop rock is pure white in color, although 
most of it is stained somewhat by limonite and organic matter. There 
is also considerable loose white sand on the slopes below the crest of 
the ridge. On the whole this portion of the ridge appears favorable 
as a possible site for a glass sand quarry. 

Continuing northward the Oriskany outcrop makes a broad curve 
in northern Huntingdon county, until, northwest of the town of Hunt- 
ingdon, it becomes Warriors Ridge, which then continues in a south- 
westerly direction into Bedford county. Between Sand Hidge and 
Warriors Ridge the Oriskany is covered by a thick series of Devonian, 
Mississippian, and in the southern part of Huntingdon County by 
Pennsylvanan strata, which have been preserved from erosion in a 
broad synclinal basin pitching toward the southwest. 

West of Huntingdon the Oriskany has a very broad outcrop, due 
to the fact it has only a very slight dip to the southeast and several 
minor flexures are present in the stratta. Where the Juniata River 
crosses Warriors Ridge through a gap the sandstone is well~exposed 
on both sides of the River. Most of it consists of a light buff colored 
quartzite. In thin section, under the microscope, it is seen to be 
made up of an interlocking mosaic of irregular shaped quartz grains, 
with occasionally a little iron oxide between them. Dust like in- 
clusions are abundant in many of the grains, while others hgve needles 
of rutile or minute prismatic crystals of apatite. From the distri- 
butions of the inclusions in them some of the grains show that origin-, 
ally they had a rounded outline. 

On the southwest side of the river, along the top of the ridge, which 
is broad and fairly level with only minor valleys, the quartzite at 
numerous places has been disintegrated sufficiently by weathering to 
cause it to crumble readily into sand. The pulpit rocks of this r^on 
have already been referred to in Chapter XV, under the head of sec- 
ondary changes in the Oriskany sandstone. A number of sand pits 
have been opened in the Oriskany on Warriors Ridge along the Hunt- 
ingdon-Alexandria road, northwest of Huntingdon, but this sand is 
only used at present for building purposes in the neighborhood, be- 

ruTi: I.XXI. 

I I I I 1 400 feet 

n of Saiiil Gkltn- 3} milra n»rth of Mill Crpok. 

FiK- '2. Abnnil»ni'<l 

1 Oriskany saniUtonc at AIcConiirltntoWD. 


k • 



ing hauled to Huntingdon in wagons* The first quarry along this 
road is that of £• C» Jones. It is located about one and one-half miles 
northwest of Huntingdon, a little northeast of the main highway. 
The working face is about 240 feet long and 20 to 25 feet high, with 
one or two feet of surface soil. The sandstone for the most part has 
become disintegrated to a loose cream colored sand, too high in iron 
\ to be available for glass making. A few boulders of sandstone are 
I still present in this sand, which require crushing. These are thrown 
■ aside at present. Not far beyond, and also on the northeast side of 
the road a similar sand. bank has been opened by Scott Hewitt for 
supplying Huntingdon with building sand. A few hundred feet-be- 
yond is the sand bank of John Schulz. Most of the sandstone at this 
place also disintegrates readily into a loose light yellowish brown 
! sand, which can be shoveled into wagons. Some rock is also present 
which would require crushing and is, therefore, thrown aside at pres- 
eiit. This rock is usually nearly white when broken into. In sum- 
marizing it may be said that no deposits have been opened up along 
this portion of Warriors Ridge which could be marked as first class 
glass sands. 

Southwest of Huntingdon, at McConnellstown, a stream has cut 
V a gap through Warriors Ridge. On the south side of this gap a 
quarry was operated in the Oriskany sandstone to supply the Colonial 
Iron Company of Riddlesburg with furnace sand. At present it is 
idle. At this place the formation has a thickness of 60 feet and dips 
19** to the southeast. The upper portion contains very little iron 
and crumbles readily to a very light cream yellow sand. Parts of 
this should yield a fairly good quality of glass sand. The lower half, 
on the other hand, is badly stained by limonite. Figure 2, Plate 
LXXI, is a view taken in this quarry looking southwest. The ridge 
rises about 75 feet above the bottom of the quarry and is covered by 

from two to three feet of soil. 


I Continuing southward along Warriors Ridge the next opening en- 

countered is that of the Standard Sand Company at Brumbaugh's 
r Siding. At the time of the writer's visit in 1914 this property was 
f also idle. The sandstone has a thickness of 85 feet and dips 20° to 
j the southeast. It has undergone considerable disintegration so that 
f it crumbles readily into loose sand in the hand. Most of it con- 
i tains a good deal of argillaceous or clayey material and practically 
I all of it is discolored by limonite to a yellowish brown. The upper 
portion of the formation contains the least amount of iron. No 
first class glass sand can be produced at this place and it is doubtful 
if even a No. 2 sand could be obtained by washing. From the equip- 
j ment of the plant erected at the quarry it is evident that no attempt 

i was made to produce any glass sand, as this consists simply of a jaw 


crusher, dry grinding pan and revolving screen, with the necessary 
elevators to handle the sand, and a boiler and engine to run the ma- 
chinery. Figure 1, Plate LXXII, shows a view of this quarry. It 
has been opened up in two benches, the upper one of which has a 
depth of from 3 to 20 feet, consistiing largely of strippings, while the 
floor of the lower one is 16 feet below that level. 

At Marklesburg, along the north side of the road leading to the 
west, a sand bank for local use has been opened on the north side of 
the road on the property of H. B. Brenneman. The Oriskany in 
this vicinity has a very flat dip, this being o^ly about 4*^ to the south- 
east. As a result the outcrop is wide. It has been opened up for a 
horizontal distance of 420 feet at right angles to the strike. At pres- 
ent the main quarry has a working face 240 feet long and varying in 
height from 20 to 25 feet, wifh one to two feet of soil. The rock is 
all thoroughly disintegrated and crumbles readily to sand in the hand. 
Considerable argillaceous material is present and it is rather badly 
stained by limonite, which renders it unfit for glass making pur- 
poses. • Figure 2, Plate LXXII, shows the appearance of this quarry. 

South of Marklesburg the Oriskany sandstone has not been disin- 
tegrated to loose sand at all places along Warriors Ridge. North 
of Hummel Station, where it rises as a very prominent topographic 
feature to an elevation of nearly 300 feet above the level of the valleys 
on either side, it consists of a hard, buff colored, quartzite. At Hum- 
mel Station and for some distance to the south it has again under- 
gone considerable weathering, so that it crumbles comparatively read- 
ily into sand. 

At Hummel Station on the southwest side of the gap through the 
ridge, which is comparatively low at this place, the Hummel Sand 
Company has opened a quarry in the Oriskany sandstone from which 
they intend to ship some glass sand. Seventy-five feet of sandstone 
are exposed. The dip is 38° to the southeast. At the time of the 
writer's visit, in August 1914, exploratory work had hot yet proceeded 
very far so that the formation was nowhere exposed more than ten 
feet below the surface. The lower portion of the formation is the 
most disintegrated. Considerable loose sand of a yellowish brown 
color is present, with masses of readily crushed sandstone, usually 
stained somewhat with limonite, imbedded in it. The upper portion 
is firmer. * Considerable fracturing has occurred and some discolor- 
ation by limonite along the joints thus developed has taken place. 
Much of this rock has a white color, although often when blocks of ap- 
parently white sandstone are broken into discoloration by limonite 
is found on the inside. The upper ten feet of the formation have 
very coarse texture. The type of rock thus far opened up at this 
place will yield only a second class sand on washing. 

I'l.ATI-; LXXll. 

iiirry <in farm «f H. D. llnnnrman at Harklesbnrg. 



Not far beyond the above quarry Warriors Ridge passes into Bed- 
ford County. It is therefore referred to again in the discussion of 
the sand deposits of that county. 

Along Chestnut Ridge, on the east side of Jacks Mountain, the Oris- 
kany sandstone does not crop out at the surface in the form of promi- 
nent ledges. Usually the outcrop is marked simply by loose boulders 
of sandstone along the top of the ridge, with occasionally a project- 
ing mass of the formation itself. At Mount Union its thickness is 
95 feet, with a dip of 24° to the southeast. At Three Springs, where 
it ia exposed in the railroad cut, the thickness is 75 feet and the dip 
35° to the southeast. 

Nowhere along Chestnut Ridge, so far as observed by the writer, 
does the outcrop have an appearance indicating that the underlying 
sandatone might be suitable for glass sand. The boulders of loose 
rock are usually only moderately rounded and are fairly hard. Where 
the formation itself crops out at the surface this is often a bluish 
gray quartzite. Mr.l. N. Swope of Huntingdon, informed the writer 
that the att^npt was at one time made to quarry the sandstone of 
Chestnut Ridge for glass sand on the northeast side of the Juniata 
river, near the railroad bridge, but that the enterprise was abandoned 
because too much calcareous material occurred in it. The writer 
made a number of thin sections of the sandstone from the least altered 
rock found along Chestnut Ridge at various places, but in no case 
was he able to detect any calcite in them under the microscope. It, 
therefore, seems more likely that the attempt was abandoned be- 
cause the rock was found to be too hard to crush economically. 

Between Jacks Mountain and Black Log Mountain the Oriskany 
sandstone is covered by later Devonian strata in another southwest- 
erly pitching syncline. Oriskany outcrops occur again on the west 
side of Black Log Mountain. Attention has already been called to 
the fact that north of Shirleysburg several minor flexures in this syn- 
cline bring the Oriskany sandstone to the surface several times. 
The writer did not have sufficient time to examine the whole out- 
crop of this region in detail. Prom observation made, however, it 
was seen that much of the formation was still a hard quartzite at 
the surface. At a number of places, however, weathering to friable 
sandstone and even loose sand has occurred. 

One of these occurrences is located one and one-half miles north- 
east of Shirleysburg, along the road up Fort Run valley, on the 
property of David Gumbert. Here along the southeast side of 
the road there is an opening about 30 feet wide and 15 feet high, 
from which sand has been taken for local use largely for building 
purposes. Tlie Oriskany formation, which dips 50® to the northwest 
at this place, ba^ become disintegrated into a loose cream colored 


sand. South from this opening the ridge formed by the Oriskany 
rises to an elevation of about 95 feet above the level of the road. The 
entire thickness of the formation is not exposed and for this reason 
could not be determined. Very likely, however, a considerable de- 
posit of sand is present, but from present exposures indications are 
that it would not be suitable for anything better than a second class 
glass sand, even after washing. 

About one mile northeast of Orbisonia, along the road. leading up 
the valley on the west side of Black Log Mountain, not far north of 
the place where the creek has cut a gap through Sandy Ridge, which 
is underlain by the Oriskany, disintegration has also gone on to such 
an extent that much of the sandstone near the surface is a loose sand. 
Several openings have been made along the outcrop to supply the 
local demand for sand. The sand exposed varies from a light gray, 
through cream, to light yellowish brown in color, and should on wash- 
ing readily yield a second class sand. From surface indications a 
considerable deposit of it seems to be present. Along the sand ridge, 
southeast of Orbisonia, on the south side of Black Log Creek gap, 
another opening has been made to supply sand for concrete. The 
sandstone at this place, with the exception of a hard ledge along the 
upper portion of the formation, also crumbles readily into a light yel- 
low sand. 

The outcrop along the southeast side of Shade Mountain and the 
northwest side of Tuscarora Mountain were not examined. Even 
if good glass sand deposits are there they would not be available at 
present for lack of transportation facilities. 

History of the Glass Sand Industry in Huntingdon County. 

The first glass sand from the Mapleton district was shipped in 
1852. At that time the sand rock as taken from the quarries was 
shipped direct to the glass factories without any further treatment. 
After a time crushers were introduced and still later the practice of 
washing and drying the sand came into vogue. 

In 1876 two quarries were opened along Sand Ridge, south of the 
Juniata river, one in the borough of Mapleton and the other in Union 
township, just south of the borough limits. The one in the borough, 
called the South Side Sand Quarry, was operated by Samuel Hatfield, 
Jr. It is at present owned by the Pennsylvania Glass Sand Com- 
pany. The other, named the Glendower Sand Quarry, was opened 
by the J. M. Maguire Company, but was purchased in the autumn of 
1881 by Dull, Wilson and Gray. In 1883 about 15 men were employed 
at each of these quarries and the aggregate monthly shipments 
amounted to 100 car loads of sand. At present the latter quarry is 
operated by the Pittsburgh White Sand Company. This Company 


has recently opened another quarry farther to the south along the 
ridge. South of the first quarry of the Pittsburgh White Sand Com- 
pany the Juniata White Sand Company also has a quarry in operation 
at present. 

At the time Report T of the Second Geological Survey of Pennsyl- 
vania was published (1885) the first quarry along Sand Ridge north of 
Mapleton had already been abandoned At the present site of the 
Keystone Works of the Pennsylvania Glass Sand Company, B. F. 
Faust and Son operated a quarry. The rock at that time was first 
burnt and then crushed, dry, with a stamp machine, without wash- 
ing. The present South Columbia quarry of the Pennsylvania Glass 
Sand Company was operated by J. W. Mattem. Only the lower por- 
tion of the formation was used. About 20 to 25 tons of sand were 
shipped daily, largely to Pittsburgh factories. The abandoned Frank- 
lin Quarry of the Pennsylvania Glass Sand Company was then owned 
by the Juniata Sand Company, which produced a second class sand 
for bottles, fruit jars, and window glass, from the lowest 30 feet of 
the sandstone, which are the purest and most friable. A steam 
crusher and washer were used to prepare about 35 tons of sand daily 
for shipment to Pittsburgh, Wheeling, Bellaire and other glass 

The WcBtbrook Glass Sand Company operated a two pan mill of 
about 300 tons daily capacity for a time at Mill Creek, but on ac- 
count of the hard quartzite nature of the rock in its quarry, the 
project was abandoned several years ago. 

Description of Glass Sand Quarries and Plants Now in Operation. 
In 1914 four companies were operating glass sand quarries in Hunt- 
ingdon county, namely: — the Pennsylvania Glass Sand Company, the 
Pittsburgh White Sand Company, the Juniata White Sand Company, 
and the Hummel Sand Company. Of these the Pennsylvania Glass 
Sand Company is the largest producer. This Company operates three 
plants at Mapleton, known as the Mapleton Works, the Keystone 
Works, and the Columbia Works, respectively. The Pittsburgh White 
Sand Company has two plants south of Mapleton, and the Juniata 
White Sand Company one, situated along the Juniata River in the 
town itself. The Hummel Sand Company was erecting a plant 
at Hummel Station on the Huntingdon and Broad-Top Mountain rail- 
road, 18 miles south of * Huntingdon, in 1914. 

Mapleton Works of the Pennsylvania Glass Sand Company. 

The Mapleton Works of the Pennsylvania Glass Sand Coiiipany are 
located just south of the town of Mapleton, on the east side of Sand 
Ridge. The plant which is connected with the main line of the Penn- 
sylvania railroad by a siding, is located at the quarry. 
13 - 


Sand Ridge rises to an elevation of about 120 feet above the level 
of Scrub Run at the north End of the quarry and 165 feet at the south 
end. The valley of this creek separates Sand Ridge from Jacks 
Mountain at this place. The floor of the quarry is about 50 feet 
above the level of the run. The Oriskany sandstone has a .thickness 
of 168 feet and dips 53^ to the northwest. At about the middle of 
the formation is a fossileferous bed of conglomerate, with quartz peb- 
bles up to one-quarter inch in diameter. This conglomerate ranges 
in thickness from three feet at the north end to one foot at the south- 
em end of the quarry. Quartz pebbles are also present occasionally 
at other horizons in the sandstone. 

The sandstone has been badly fractured. Along the joint planes 
thus formed moderate amounts of iron in the form of limonite have 
been deposited from iron bearing solutions. Where the fracturing 
is especially intense in some cases the limonite has penetrated the 
rock itself. Portions of the rock also show occasional rust spots, 
dut to the weathering of some iron bearing mineral present in the 
rock. Occasionally a little black oxide of manganese has also been 
deposited as dendritic growths along some of the fracture planes. 
Outside of this the rock is nearly pure white quartz sandstone. It 
has undergone considerable disintegration through weathering, so that 
most of it crumbles readily into sand between the fingers. There 
are portions, however, which have escaped this weathering process 
and are still white to buff colored quartzites. Where these are en- 
countered in considerable masses in the quarry they are left behind, 
the softer rock around them being removed. 

The sandstone has been quarried for a distance of 1200 feet along 
the strike. At present both ends of the quarry are being worked, 
the highest portion of the north face rising about 70 feet above the 
floor of the quarry and the south face 115 feet. The rock is blasted 
down, advantage being taken of the fracture planes, and loaded into 
cars which are hauled to the plant by mules. 

The Mapleton Works is equipped with two jaw crushers, and two 
siz foot chaser mills to crush the stone into sand. Washing is done 
in screw washers of the type already described in a previous chapter 
of this report For drying the sand, steam dryers are employed. 
The flow sheet of this plant is given on Plate LXXIII. The ma- 
chinery is operated by electric power. Figure 1, Plate LXXIV, 
shows the external appearance of the works, while Figure 2, Plate LIX 
shows at the left in the foreground, the northern end of the quarry 
and at the right the plant for treating the stone. Most of the out- 
put is sold as No. 2 sand, although No. 1 sand can also be produced 
by sorting the rock in the quarry and using only the portions lowest 
in iron content for this grade. 

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Keystone Works of the PenDsylvania Glass Sand Oompany. 

The Keystone Works of the Pennsylvania Glass Sand Company are 
located about one mile north of Mapleton, on the east side of the 
Juniata River and on the west side of Sand Ridge, which in this vi- 
cinity rises as a steep escarpment to about 240 feet above the level 
of the valley. Plate LXVIII shows the appearance of the ridge 
at this place as seen from the west with the two quarries of the Key- 
stone works at the right. Figure 2, Plate LXXIV is a nearer view 
of the plant with the North Quarry as a background. It is con- 
nected with the main line of the Pennsylvania railroad by a siding, 
which runs along the east side of the Juniata River at the foot of 
Sand Bidge. 

The Oriskany sandstone in the vicinity of the Keystone Works has 
a thickness of about 130 feet. At the South Quarry the upper 80 
feet of the formation have been quarried for a distance of ^300 feet 
along the strike, while at the North Quarry, which is 300 feet to the 
northeast along the ridge, it has been quarried for a distance of 690 
feet. The rock at both places is of excellent quality, being pure 
white in color and only moderately hard. Very little iron stain oc- 
curs along the joint planes. The following analysis of a sample of 
the sandstone from this vicinity shows its chemical composition : 

Analysis of Sandstone from Keystone Works, Mapleton. 

SiO, 99.76 

AlaOa - 14 

FeaO». .07 

MgO, ^ none 

CaO. .28 

HaO, 09 

TlOa. - - - .02 


In one place in the North Quarry the footwall has been broken 
through, thereby allowing a large amount of the underlying shale 
to be washed into the quarry. This has caused considerable incon- 
venience. At the south end of the quarry a streak of cream colored 
sand was encountered near the footwall. The quarries are both 
worked in two directions and it will, therefore, not be long before 
they meet. Plate LXIX, shows the appearance of a portion of the 
northeast working face of the North quarry at the time of the writer's 
visit in 1914, The rock is blasted down and loaded into cars which 
are hauled to the plant by mules. 

At the plant the stone is crushed to sand by passing it through 
jaw crushers and chaser mills. Screw washers are used for washing 
the sand. After it has been allowed to drain for about 12 hours the 
washed sand is passed through a steam dryer before it is given a 
final screening. Plate LXXV gives a flow sheet of the mill, showing 
the treatment the sand receives from the time it reaches the plant 


until it is ready to be loaded on cars. There are two six foot and 
one eight foot chaser mills. WUh the type of sandstone encountered 
in the two quarries these ai*e capable of turning out 300 tons of sand 
per day of ten hours. About 1000 gallons of water, obtained from 
the Juniata River, are used per minute. The two six foot mills 
are run by steam, while electric power is employed to operate the 
eight foot mill. 

The greater portion of the output is No. 1 sand for glass manu- 
facture. The following two analyses show its composition: 

Analyses of No. 1 Sand from Keystone Works. 

1. 2. 

SiO«. - - - - 99.36 99.70 

AlaO. .17 .24 

FeaOs - 06 .026 

MgO, -.-. - _ none trace 

CaO, _- _ 28 trace 

H,0 18 

TiO* 02 

100.02 99.966 

No. 1 analysis by Charles R. Fettke. 

No. 2 analysis by Booth, Garrett and Blair of Philadelphia. 

The size of the grains is shown by the following screen analysis: 

Through 14 mesh remaining on 20 mesh (.0328 inches diameter), .07 

Through 20 mesh remaining on 28 mesh (.0232 inches diameter) 1.59 

Through 28 mesh remaining on 35 mesh (.0164 inches diameter). 13.11 

Through 35 mesh remaining on 48 mesh (.0116 inches diameter), 61.71 

Through 48 mesh remaining on 65 mesh (.0082 inches diameter), - 20.35 

Through 65 mesh remaining on 100 mesh (.0058 inches diameter). - 2.79 

Through 100 mesh remaining on 150 mesh (.0041 Inches diameter). — 16 

Through 150 mesh remaining on 200 mesh (.0029 inches diameter), 03 

Through 200 01 


Figure 1, Plate LXXVI shows the angular shape of the grains of 
this sand. The amounts of numbers 2 and 3 sand produced at the 
Keystone Works is relatively small on account of the excellent quality 
of the sandstone encountered in the quarries which supply this plant. 
The sand is divided into diflPerent grades on the basis of its iron con- 
tent, the division being made in the quarry by roughly sorting the 
rock into different classes according to the amount of iron stain or 
limonite which it shows. 

Columbia Works of the Pennsylvania Glass Sand Company. 

The Columbia Works of the Pennsylvania Glass Sand Company is 
situated about three-fourths of a mile northwest of the Keystone 
Works, on the same side of Sand Ridge. They are also connected 
with the main line of the Pennsylvania railroad by a siding. Two 
quarries supply this plant with sandstone. 

The South Quarry is located on the north side of a small creek 
which has cut a gap in Sand Ridge at this place. The Oriskany for- 
mation here has a thickness of about 200 feet and dips 02° to the 









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t Hummel Stntinn, Pcnnu. 


northwest. The top of the ridge rises 110 feet above the floor of 
the quarry. Figure 1, Plate LXX shows a view looking northeast 
towards the present working face. The sandstone is also pure 
white in color, but is somewhat harder than that encountered in the 
Keystone Quarries. Most of it cannot be crushed to sand between 
the fingers. It is badly fractured, as the illustration referred to 
above shows. Recently another quarry has been opened up about 
700 feet to the northeast along the ridge. At the time of the writer^s 
visit only the upper portion of the formation had been exposed. This 
is also pure white in color and is more friable than that encountered 
in the South Quarry. Much of it can be readily crushed to sand be 
tween the fingers* Figure 2, Plate LXXVI shows a portion of the 
working face of this quarry as it appeared in 1914. 

At both quarries the sandstone is blasted down and loaded into 
cars which are hauled to the plant by mules. Here it is passed 
through jaw crushers and chaser mills. The'i*esulting sand is then 
washed and dried in steam dryers. Plate LXXVII, gives the flow 
sheet at this plant, which is divided into two separate and independent 
units, each of which is provided with an eight foot chaser mill. The 
machinery is operated by steam power. Water for the chaser mills 
and screw washera is pumped from the Juniata River. 

The output of the Columbia Works consists largely of No. 1 sand. 
The following analysis made by Booth, Garrett and Blair of Phila 
delphia, shows its composition : 

Analysis of Sand from the Columbia Works. 

SiOt 99.72 

Al.O. „ 25 

FetOa. -. 014 

MgO - — trace 

CaO, - - - trace 

Pittsburgh White Sand Company. 

The two plants of the Pittsburgh White Sand Company are located 
about two-thirds of a mile southwest of Mapleton, on the west or 
Hares Valley side of Sand Ridge. They are connected with the main 
line of the Pennsylvania railroad by a spur up the east side of Hares 
Valley. Two quarries are operated to supply these plants with sand- 

The North, or oldest quarry, is situated at the sand washerids. On 
the northeast this quarry adjoins the Mapleton quarry of the Penn- 
sylvania Glass Sand Company. The two properties overlap one 
another here for a short distance, the boundary line running along 
the top of the ridge. The quarry has been opened for a distance of 
about 2000 feet along Sand Ridge. Figure 1, Plate LXXVIII, shows 
a view of it taken from the southern end looking northeast. The 


ridge rises to a maximum elevation of 160 feet above the bottom of 
the quarry. At the southwest end there is a bench 450 feet long, 
rising 95 feet above the present floor of the quarry. This bench is be- 
ing taken out at the present time. Plate LVI shows a portion of 
the working face at this end of the quarry. 

The Oriskany has a thickness of approximately 130 feet and dips 
65J° to the northwest in this quarry. There has been considerable 
fracturing, producing one set of joint practically parallel to the bed- 
ding plane, while another set has a strike gf N 69*^ E and a dip of 65° 
to the northwest. A screen analysis of a series of samples taken 
across the sandstone gave the following results: 

Screen Analysis of Sandstone from Pittsburgh White Sand Company's 

Quarry, Mapleton. 

Passed through 4 mesh, remaining on 6 mesh (.131 In. diameter), .42 

Passed through 6 mesh, remaining on 8 mesh (.093 in. diameter), .73 

Passed through 8 meshe remaining on 10 mesh (.065 in. diameter), 1.73 

Passed through 10 mesh, remaining on 14 mesh (.046 In. diameter). 1.57 

Passed through 14 mesh, remaining on 20 mesh (.0328 In. diameter), 2.42 

Passed through 20 mesh, remaining on 28 mesh (.0232 In. diameter), 7.36 

Passed through 28 mesh, remaining on 35 mesh (.0164 in. diameter), 18.90 

Passed through 35 mesh, remaining on 48 mesh (.0116 in. diameter), 47.84 

Passed through 48 mesh, remaining on 65 mesh (.0082 In. diameter), 14.71 

Passed through 66 mesh, remaining on 100 mesh (.0058 in. diameter), 2.18 

Passed through 100 mesh, remaining on 150 mesh (.0041 in. diameter), .48 

Passed through 150 mesh, remaining on 200 mesh (.0029 In. diameter), .37 

Passed through 200 .42 


The sandstone is blasted down, as at the other quarries, loaded 
into cars and hauled to the plant by mules. Only one working face 
on the lower bench, near the southwest end of the quarry, is main- 
tained at present. 

In the northeast comer of the quarry, where it adjoins the prop- 
erty of the Pennsylvania Glass Sand Company, the lower portion of 
the formation is somewhat harder and can only be disintegrated be- 
tween the fingers with difficulty. It consists of white sandstone 
with occasional specks of limonite. A miscropic examination of the 
rock showed that these occasional yellowish brown specks in the 
sandstone are probably due to the weathering of scattered grains of 
hornblende in the rock. 

About three-fourths of a mile to the south, and along the west side 
of Sand Ridge, the Pittsburgh AVhite Sand Company is opening up 
another quarry. At the time of the writer's visit no very great 
thickness of sandstone had yet been opened up by the quarrying opera- 
tions, which were still confined to the upper portions of the formation. 
The sandstone at this place is somewhat harder than that exposed in 
the other quarries along Sand Ridge south of Mapleton, it being only 
possible to crush small fragments of it between the fingers with dif- 
ficulty. It is white in color, except where it has been stained by a 
little limonite along a plane of fracture. The broken rock from this 












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Sand Rock from Quarry 


Jaw Crusher 


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Id-me^h Revolvmo Screen IE-mesh frevolvmci >5creen» 

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3 ^cnew yf>/p3hens 3 5cre^ Washers, 

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^crew Conveyor4. 

Disfnbuhncj BeltConve^r 
Drotnincf Floor 
Shoveled by Honci 
Bucket EievQ for 
Belt donveyfor 
BucHet Elevator 

Brich Dryinq Stach 

^cre\^^ Conveyor 

Bucket Elevator 

3heei Iron Coolino Tower 
BucHef Elevotot 
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Flow slieet of South Plant of Pittsburgh White Sand Company, Maplcton, Penna. 

quany is hauled to the washeries by means of a small steam loco- 
motive running on a track along the foot of Sand Bidge. 

Two separate plants have been erected for preparing the sand for 
market. The method employed is essentially the same as that of the 
other plants in the Mapleton district. Plates LXXIX and LXXX 
give the flow sheets of the two washeries. Direct heat dryers, burn- 
ing coke, are used instead of steam dryers. Two different types 
are employed, that at the lower plant being a Cummer dryer, 26 feet 
long and 10 feet in diameter, and that at the upper works a brick 
stack dryer. At the lower plant there are two chaser mills, while 
at the upper one only one has been installed. The machinery at 
both places is operated by steam power. Water for the chaser mills 
and washers is obtained from Hares Valley creek. It is first pumped 
to a tank on top of a hill west of the plant and is then allowed to 
flow to the plant by gravity. Three grades of sand are produced by 
roughly sorting the stone in the quarry. The following analysis of 
a sample of No. 1 sand from the plant of the Pittsburgh White Sand 
Company, made by the Chief Chemist of the Pittsburgh Plate Glass 
Company, gives the chemical composition: 

Analysis of No. 1 sand from plant of Pittsbargh White Sand Company. 

SiO. 99.885 

Al.O. 022 

Fe,0. -. 047 Pe .033 

MgO, trace 

OaO _ 020 

Loss on ignition, .020 


Juniata White Sand Company. 

The plant of the Juniata White Sand Company is situated in the 
town of Mapleton, on a short siding of .the Pennsylvania railroad. 
The quarry from which the sandstone is obtained is located about 
one and one-fourth miles south of the town, on the west side of Sand 
Ridge. It is connected with the plant by a narrow gauge track, 
over which the sandstone is hauled by a small steam locomotive. 

The quarry has been opened for a distance of 300 feet along the 
strike. The sandstone has a thickness of about 150 feet and dips 
63** to the northwest. The surface of the highest outcrops along 
Sand Bidge at this place rise 160 feet above the level of the quarry. 
The sandstone is white in color, except where it has been occasionally 
stained brown for several inches on either side of a pronounced joint 
plane, which allowed iron bearing solutions to filter in and precipi- 
tate limonite between the quartz grains. Here and there portions of 
the rock have scattered through the minute specks of limonite, 
which are probably due to the weathering of occasional grains or horn- 
blende, which a microscopic examination of the rock showed to be 
present. Fracturing in the sandstone is pronounced. While the 



Abundant deposits of somewhat inferior grades of sand also oc- 
cur along Warriors Ridge at places where at present they are only 
made use of in small quantities for local use as building or furnace 
sand. Where only a second grade glass sand is desired these de- 
posits are available. Similar deposits occur at several places along 
the Oriskany outcrop on the western side of Black Log Mountain, 
especially in the vicinity of Orbisonia, but these are not as con- 
veniently situated with respect to transportation facilities as are the 
Warriors Ridge deposits. 




Location of Outcrops. 

Miftlin County, which adjoins Huntingdon County ou'the northeast, 
has had the same geological history that the latter has passed 
through. It is underlain by the same fonnations and the gologic 
structure is similar. The youngest beds of which any remnants- 
have been left by erosion belong to the upper Devonian, while the 
oldest strata exposed are of Ordovcian age. The Tuscarora sand- 
stone is also the ridge making rock of the region. Its outcrop forms 
Standing Stone Mountain along the northwestern boundary of the 
county, Jacks Mountain along the center, and Blue Ridge along the 
southeastern boundary. Between Standing Stone and Jacks Moun- 
tains there is an anticline while between Jacks Mountain and Blue 
Ridge a syncline occurs. 

A comparatively small remnant of the Oriskany, which at one 
time covered this entire area, has been preserved from erosion in the 
syncline between Jacks Mountain and Blue Ridge. *A number of 
minor flexures occur along the axis of this syncline, which runs across 
MifSin county in a northeast-southwest direction. As a result the 
outcrop of the Oriskany formation forms a number of roughly par- 
allel bands which cross the central portion of Mifflin County from 
the northeast to the southwest boundary, as shown on the map of 
Huntingdon, Mifflin and Bedford counties given in Plate LXV, which 
has the outcrops of the Oriskany sandstone indicated on it. Plate 
LXXXII shows a section at right angles to the strike of the forma- 
tions in the vicinity of McVeytown. Tliree of the minor synclinal 
flexures present here in the broad syncline of southeastern Mifflin 
county contain remnants of the Oriskany sandstone, which have been 
])reserved from erosion. Much of the Oriskany sandstone of Mif- 
flin county is still a hard white quartzite, which is fairly resistant to 
erosion, so that it often forms minor ridges in central Mifflin County. 
Under certain favorable conditions, however, it has been thoroughly 
disintegrated by circulating water to a friable sandstone, and in 
places even to a loose sand. 

Workable Portions. 

Portions of the Oriskany sandstone suitable for glass sand occur 
in the vicinity of Bumhara, north of Lewistown; near Granville, 
southwest of Lewistown ; at McVeytown, and in the district around 
Vineyard. ^ 


The syucline northeast of Bumham contains a narrow belt of Oris- 
kany sandstone, together with a little overlying Devonian shale, pre- 
served from erosion along its axis. It pitches toward the north- 
east so that this strip of overlying Devonian shale gradually be- 
comes wider and wider as the Oriskauy along the axis becomes 
bnried deeper and deeper toward the northeast A low ridge 'is 
formed by the northwest or steep limb of this syncline northeast of 
Bnmham. The southeast limb has a gentle dip, as a rule, and crops 
out along the east side of this ridge. Usually it is covered by soil 
which has been washed over it from higher up the slope. At Burn- 
ham, Kishickoquillas Creek has cut a valley through it where it 
crosses at right angles. All of the Oriskany has been removed at this 
gap, the valley being deeper than the former level of the Oriskany 
-along the axis of the syncline at this place. Northeast of Burnham, 
along this ridge, Oriskany outcrops are encountered, which in places 
have weathered to loose sand. 

The first opening is that on the property of John Miller, situated 
about one and three-fourths miles northeast of Bumham. The south- 
east limb of the syncline which crops out on the southeast slope of 
the ridge at this place has a very gentle dip to the northwest. Mr. 
Miller has driven a tunnel into the hill, approximately 700 feet long, 
to cut the sandstone at a level of about 100 feet below its outcrop. 
The sandstone of this limb of the syncline has been disintegrated to 
loose sand by the agents of weathering. As exposed in the caved 
openings along the outcrop above the mine workings, it is seen to be 
a light, yellowish brown in color and appears as though it ought to 
yield a No. 2 sand on washing. An analysis made by the writer of a 
sample obtained at this place gave .18% FOjOa. The following screen 
analysis gives the percentage of the different sized grains present in 

this sand: 

Passed through 14 mesh, remained on 20 mesh (.0328 inches), — 02% 

Passed through 20 mesh, remained on 28 mesh (.0232 inches), 21% 

Passed through 28 mesh, remained on 35 mesh (.0164 inches) 1.13% 

Passed through 35 mesh, remained on 48 mesh (.0116 Inches) 10.48% 

Passed through 48 mesh, remained on 65 mesh (.0062 inches) 56.76% 

Passed through G5 mesh, remained on 100 mesh (.0058 inches), 25.43% 

Passed through 100 mesh, remained on 150 mesh (.0041 inches) 2.64% 

Passed through 150 mesh, remained on 200 mesh (.0029 inches) 1.30% 

Passed through 200 mesh 1.58% 


The outcrop of the northwest limb of the syncline at this place 
occurs along the top of the ridge. It is marked by a prominent pro- 
jecting ledge of fairly hard sandstone and a large number of detached 
boulders. The boulders and outcropping ledges are mostly angular, 
only a little rounding of the comers having occurred. This indicates 
that the rock underneath is fairly hard. The rock of the ledges and 
boulders is also spotted more or less by limonite which renders it 
unfit for a first class glass sand. Figure 1, Platfe LXXXIII, shows a 


I I 1 1 ' 120/eef. 

Fig. 1. Cross section of ridge northeast of Burnham, at John Millers Sand 

Mine, showing position of Oriskany sandstone. 

• « « 



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Fig. 2. Similar section at sand pit of Standard Steel Company. 
(See figure 3 on other sheet of illustrations.) 


Friable sandstone and loose sand also occur in the middle syncUne 
between Lewistown and Burnham, on the southwest side of Kishicko- 
quillas valley. Some sand has been taken out on the southwest side 
of the road, up a small vaUey, which has been cut across the Oris- 
kany outcrop at this place. Most of the rock is exceedingly friable 
and breaks up readily into a light, yellowish brown sand. Portions 
of the formation are very fossiliferous. On the northeast side of 
this same valley a quarry has been opened on the northwest limb of 
the syncline. The floor of the quarry is a little above the level of 
the creek and the working face is about 55 feet high. Northeast 
of the quarry the ridge formed by the Oriskany outcrop is about 110 
feet wide. Most of the sandstone disintegrates readily into sand; 
Considerable iron in solution has filtered in along joint planes and 
has been deposited in the sand on either side as limonte, as a result the 
sand derived from it is not white and careful sorting in the quarry 
would have to be resorted to to make even a No. 2 grade of glass 

About 700 feet northeast of the above quarry a pit has been opened 
in an open field in the loose sand occurring along the Oriskany out- 
crop. It is about 120 feet long, 50 feet wide, and 20 feet deep, with 
about 3 feet of surface soil. This pit is also on the northwest limb 
of the syncline. The sand docs not contain as much limonite as that 
from the quarry described above, being lighter in color. 

Another sand bank to supply the local demand for building and 
other sand has been opened in the southwestern part of the town of 
Lewistown, on the southeast limb of the easternmost of the three 
synclinal flexures between Bumham and Lewistown, where a small 
creek has cut a valley across the formation south of EishickoquiUas 
creek. This sand bank is situated on the northeast side of this 
valley. The formation here dips 40° to the northwest. Its upper 
portion is very fossiliferous and is stained with considerable limonite. 
It crumbles qute readily into sand. The lower porton on the other 
hand contains very few fossils and is mtich lighter in color. Portions 
of it are almost pure white. The hill at this place rises about 120 
feet above the floor of the lower opening. About 25 feet below the 
top is anotlier opening. In it the upper 20 feet are also very fossilif- 
erous and are pretty badly discolored by limonite, while the lower 25 
feet consists of fairly friable sandstone which crumbles readily into 
sand. ' Here and there, however, some limonite occurs in it along 
seams running in various directions. A fault, nearly parallel to the 
strike, separates the upper and lower portions of the formation, which 
is, therefore, undoubtedly over 45 feet thick at this place. 

About three and three-fourths miles southwest of Lewistown, in the 
vicinity of Granville, along the same limb of the easternmost of the 
synclines containing Oriskany sandstone, the sandstone has also been 


disintegrated by weathering into loose, and at this place, pure white 
sand. It is being mined by the Pennsylvania Glass Sand Company. 
Figure 1, Plate LVIII, shows a cross section of the syncline at this 
place. The southeastern limb, which has a thickness of 100 feet, 
dips 42^° to the northwest. It has been intersected by a cross cut 
tunnel at a depth of about 200 feet below the outcrop. Nearly all of 
the sandstone down to this level has been disint^rated by circulating 
water to a practically white sand, and indications are that this dis- 
integration has extended to still greater depths, perhaps even as far 
as the bottom of the synclinal trough. A sample of this loose white 
sand taken from one of the chutes in the mine showed on analysis the 
presence of .11% FejOa. Along the top of the ridge which is formed 
by the northwestern limb of this syncline the rock consists of a com- 
paratively hard white quartzite. 

Following southwestward, along the belt of Oriskany outcrops, ex- 
cellent deposits of glass sand are again encountered in the vicinity of 
McVeytown. These are also developed on the southeast limb of the 
easternmost of the three synclinal flexures containing Oriskany sand- 
stone, which are present northwest of McVeytown. This sand has 
been mined for a distance of nearly 4300 feet along the strike, south- 
west from the gap northeast of McVeytown. Two mines were for- 
merly situated along this outcrop, one at the gap northeast of McVey- 
town, known as the Dull mine, and the other 1700 feet to the south- 
west along the outcrop, known as the Macklin mine. Both were 
owned by the Pennsylvania Glass Sand Company at the time they 
were shut down. 

The lower workings in the Dull mine are down 180 feet below the 
present level of the water in the pit at the shaft, which is about 35 
feet above the level of the Juniata river. The outcrop of sandstone, 
dipping 62® to the northwest, on which these mines are located also 
occurs on the side of a ridge on top of which the northwestern limb 
of the syncline crops out as a comparatively hard white quartzite, 
dipping 73® to the southeast. According to J. H. Dewees'^ the Oris- 
kany sandstone at the Dull mine has a thickness of about 140 feet, of 
which the lower portion is yellow and the upper layers are bluish 
gray and yellow white, the middle 100 feet are almost pure white 
sand of excellent quality for the manufacture of glass. Mr. W. P. 
Stevenson, of McVeytown, informed the writer that the formation 
yielded a very pure white sand for a width of 110 feet in the Dull 
mine. Figure 2, Plate LVIII, shows a section of the ridge on which 
these outcrops occur at the abandoned Macklin works of the Penn- 
sylvania Glass Sand Company. It shows the hard quartzite limb of 
the syncline cropping out near the top of the ridge, while the friable 
disintegrated limb, in which the mines were opened, crops out at the 

fiS. Second Geological Surrey of PennsylTaiila, Report F, 1878, p. tt. 


surface along its southeastern side, pretty well down toward the foot 
of the slope. I^racUcally all of the sandstone of this limb crumbles 
readily into white sand in the hand, much of it being already loose 
sand as it occurs in place. 

As has already been stated loose white sand was encountered in the 
Dull and Macklin mines for a distance of over 4300 feet, southwest 
along the strike of the Oriskany formation from the gap northeast 
of McVeytown, where the Dull works of the Pennsylvania Glass Sand 
Company were formerly situated. This same bed continues north- 
east along the southeast slope of the ridge for a distance of several 
miles, but as yet has not been explored to any extent except by shal- 
low pits. It is very likely that sand of good quality will also be 
encountered when this portion of the formation is exploited. 

The other outcrops of the Oriskany to the northwest, as exposed 
along the valley which forms the gap northeast of McVeytown, were 
also examined. The rock at these places was found for the greater 
part to consist of hard white quartzite. A similar examination was 
made of the outcrops in the gap of about three miles northeast of Mc- 
Veytown. Here only two synclines containing Oriskany sandstone 
are present. The southeast limb of the easternmost of these is cov- 
ered, while the northwest limb forms the first ridge northwest of the 
Juniata Valley. A light brown sand occurs in a cut along the road 
which follows the northeast side of the valley forming the gap through 
the ridge at this place. To the northeast the ridge rises 230 feet 
above the level of the valley. There are no prominent ledges cropping 
out along it, but more or less rounded boulders of Oriskany sand- 
stone are scattered over its surface. When broken into, they are 
seen to have a light, yellowish brown color and are moderately hard, 
although pieces of the rock can be crumbled into sand between the 
fingers. Considerable quantities of white sand have also been washed 
out along the ridge. On the whole, surface indications are such as 
to warrant further exploration here for possible bodies of rock suit- 
able for glass sand. The other outcrops examined along the north- 
west-southeast valley, which connects Juniata with Ferguson Valley, 
did not look very promising for glass sand. 

About two miles southwest of McVeytown the road to Mount Union 
crosses the southwest limb of the syncline on which the Dull and 
Macklin mines are located. The outcrop is quite low at this place 
but to the southwest, beyond the creek which crosses it, it rises again 
as a rather prominent ridge. At the road the sandstone has become 
disintegrated into a light yellow sand. To the southwest the disin- 
tegration has not gone quite so far, but the rock can still for the most 
part be readily crushed into sand between the fingers. Where traced 
for a distance of about one and one-half miles the appearance of the 
outcrop is such as to indicate that the Oriskany sandstone along it 



Pig. 2. Hatfield Works ot Penuaylvauia Glass Sand CompanT, Vineyard, Pa. 


may be suitable for glass sand. Only very small amounts of limonite 
are present in the outcrop rock. Following northwest, along the 
creek referred to above, several nioi*e synclines containing Oriskany 
are crossed, but some of these outcrops have a very favorable api-ear- 
ance as possible sources of glass sand. 

Continuing further to the southwest portions of the Oriskany sand- 
stone suitable for glass sand are again encountered in the vicinity 
cf Vineyard. The first deposit is that of the Hatfield works of the 
Pennsylvania Glass Sand Company, about one mile northeast of Vine- 
yard. This quarry is located on a portion of the Oriskany sandstone 
which forms the cap rock of a synclinal ridge. Since the sand.<=!tone 
at this place occurs along the axis of the syncline it is badly fractured 
as is shown in Figure 1^ Plate LXXXIV. The Juniata River swings 
in a broad curve against the ridge at this place and has cut back 
beyond the axis of the syncline so as to expose the formation, as \ 
shown in Figure 2, Plate LXXXIV. The rock at the extreme left 
of the picture, covered largely by vegetation, is limestone dipping to- 
ward the right, while that in the railroad cut to the extreme right is 
also limestone dipping toward the left. The Oriskany sandstone 
above the limestone is shown in the quarry back of the Hatfield works 
at the center of the picture. The ridge, with the sandstone outcrop 
along its crest, can be followed for about 1500 feet northeast from 
the Hatfield quarry. Beyond, the sandstone disappears, having been 
removed by erosion along the axis of the syncline, which rises higher 
and higher in a northeast direction. At the quarry, the crest of the 
ridge is about 300 feet above the floor of the quarry. The present 
working face reaches within about 100 feet of the top and is about 
150 feet wide at the base, with a slope of 36^*^. 

Reference has already been made to the fact that the sandstone at 
the Hatfield quany is badly fractured. This has allowed ground 
water to circulate freely throughout it and has resulted in the thor- 
ough disintegration of the rock, so that most of it crumbles readily to 
a loose sand and can be washed down from the face of the quarrj^ 
by turning a stream of water under pressure against it. Some rem- 
nants of less disintegrated sandstone, however, are also present be- 
tween the fracture planes. The sand along the joint planes is dis- 
colored somewhat by limonite, while the less disintegrated sandstone 
masses as a rule are white in color and are very little stained by iron 
oxides. An average sample of the loose sand from the quarry showed 
.17% FejOg to be present on analysis. 

At Vineyard the Pennsylvania Glass Sand Company operates an- 
other quarry known as the Enterprise. This is situated on the ridge 
northwest of Vineyard on the northwest limb of the syncline on whose 
axis the Hatfield quarry is located. The formation has been quar- 
ried here for a distance of about 650 feet along the strike to a maxi- 


num depth of 125 feet below the surface of the outcrop. At the north- 
east end the quarry has a width of 180 feet at the surface and at the 
southwest end 240 feet. The dip at the middle is about 20"" to the 
southeast. This increases toward the northeast. The sandstone im 
badly fractured and disintegration along joint planes has been pro- 
nounced. Unfortunately the loose sand thus formed has been stained 
with limonite to such an extent that it is only available for No. 2 
glass sand. The masses of less disintegrated rock as a rule are white 
and comparatively free from iron so that they yield a No. 1 sand. 
The outcrop is on the side of a gentle sloping hill underlain by shale 
and limestone. The sandstone forms a low ridge on the side of this 
hill and dips away from it Drainage down the hill is toward the 
sandstone outcrop. Conditions are, therefore, favorable for an 
abundant supply of surface water getting across to the sandstone 
which explains the thorough disintegration of the latter at this 
^ quarry. 

About one mile southwest of the Enterprise quarry, along the same 
limb of the syncline, the Crystal Sand Company has opened a quarry. 
The sandstone at this place is almost horizontal and is much less dis- 
integrated than at the Enterprise quarry. It can only be crushed 
into sand with difficulty between the fingers. Considerable fractur- 
ing has occurred in the rock and some limonite has been deposited 
along practically every joint plane thus developed, but it does not 
penetrate the rock itself to any extent. The rock itself is white in 
color. The quarry has been opened for a length of about 600 feet 
along the strike and is 300 feet wide. The working face at the west 
end is 40 feet high and at the east end 20 feet. The upper 8 feet of 
sand are badly discolored by limonite. These 8 feet, together with 2 
feet of soil, have to be stripped before the underlying rock can be re- 

Continuing southwest along the outcrop the rock gradually be- 
comes more and more of the nature of a quartzite. About one-fourth 
mile south of the Crystal Sand Company's quarry the Juniata Silica 
Company at one time operated a sand plant, which was dismantled 
and abandoned a number of years ago. The Oriskany sandstone 
at this place is also very nearly horizontal. It is harder than the 
sandstone encountered at the Crystal Sand Companys quarry. The 
amount of fracturing is about the same. Limonite has been deposited 
along joint planes in small amounts, but does not penetrate the rock 
itself. Ten feet of stripping, consisting mostly of well disintegrated 
but badly iron stained Oriskany sandstone, were necessary before 
quarrying operations could be conducted. Both underground min- 
ing and open quarry methods of obtaining the sandstone were em 
ployed. This is the last place in southwestern Mifflin county at 
which any attempt has been made to obtain glass sand from the Oris 
kany sandstone. 


History of the Glass Sand InduBtry in Mifflin County. 

In 1868 openings were first made along the Oriskany outcrop in 
Granville township, three miles southwest of Lewistown, by Bum- 
gardner & Franklin, of Lancaster, Pennsylvania, who were pros- 
pecting for glass sand. A deposit of high grade silica sand was dis- 
covered and mfning operations were, therefore, commenced. A small 
plant was erected with a daily capacity of forty tons of prepared sand, 
which was hauled to Lewistown for shipment. In 1875 a cable trans- 
mission line to Granville station on the Pennsylvania railroad was 
erected and the sand was conveyed in buckets a distance of one and 
three-fourths mile to the shipping point. At the same time the out- 
put was increased to 60 tons per day. 

After the Pennsylvania Canal along the Juniata Valley was aban- 
doned, a siding from the Pennsylvania railroad Was laid down on the 
tow-path which brought shipping facilities closer to the mines. A 
large storage and drying plant were erected and the aerial tramway 
was dismantled. The sand was conveyed by means of a pipe line 
from the crushing mill to the drying and storage building and the 
capacity of the plant was increased to daily output of 75 tons. 

About this time the firm of Bumgardner & Franklin was dis- 
solved and the Juniata Sand Company was incorporated in its place. 
The stockholders were Lancaster investors, George M. Franklin of the 
old firm being the principal stockholder and president of the com- 
pany. In 1899 the output of the mine was handled by the Pennsyl- 
vania Glass Sand Company, a Delaware corporation, which also 
controlled the output of all the glass sand producing plants in the 
Juniata Valley. 

In 1902 the Juniata Sand Company sold the plant to the Pennsyl- 
vania Glass Sand Company, jvhich corporation also purchased all the 
plants whose output was at this time handled by the Pennsylvania 
Glass Sand Company, of Delaware, mentioned above. The new own- 
ers enlarged the plant and increased the output to two hundred tons 
daily capacity. - ^ 

In 18G9 Wirt & Davis operated a primitive plant at McVeytown, 
washing the sand in boxes, with a daily capacity of ten tons. The 
enterprise was a failure and in 1870 they ceased operations. B. A. 
Bradly and C. P. Dull formed a partnership under the name of Bradly 
& Dull and took over the property. They erected a small mill with 
more modem methods than their predecessors used, and increased the 
daily output to forty tons. The sand was hauled a distance of a mile 
across the Juniata River to McVeA'town station on the Pennsvlvani.i 
railroad. At this time the average capacity of a railroad car was 


twelve tons. First class glass sand sold in Pittsburgh market for 
112.00 a ton and the freight rate from MeVeytown was |3.75 per ton. 
B. A. Bradly died in 1800 and the business was continued by C. P. 
Dull, the daily capacity of the plant having been increased to 75 tons. 
In 1807, Dull installed a pump and pumped the sand through a four 
inch pipe line to a drying and storage building at the railroads, at 
the same time considerably increasing the output. In 1902 Dull sold 
to the Pennsylvania Glass Sand Company. 

In 1885 Charles Miller opened a sand deposit on the lands of D. 
M. Dull near MeVeytown. Only a small amount of sand was mined 
and the methods used were primitive. In a short time he was suc- 
ceeded by Dull, Wilson & Gray. The partnership had existed only 
a short time when Gray withdrew and the business was continued by 
Dull and Wilson. In 1800 they ceased operations and Macklin and 
Stevenson succeeded them and operated the plant until 1902 when 
they sold to the Pennsylvania Glass Sand Company, which company 
operated the Dull, and the Macklin and Stevenson plants along with 
the Granville mine until 1912, when the two plants at MeVeytown 
were abandoned. 

In 1878 David S. Forg}' and Samuel Witherow made an opening at 
Vineyard station, seven miles west of MeVeytown. They continued 
operations until 1881 when the partnership was dissolved and Wil- 
liam Ewing, James Macklin and W. P. Stevenson took a lease on the 
sand property, operating it under the name of the Enterprise Sand 
Company. 1882 the property was purchased from D. S. Forgy by 
Macklin & Stevenson who continued to operate it until 1902 when 
the business was sold to the Pennsylvania Glass Sand Company, 
which has operated the plant since its purchase by it. 

In 1886 an opening was made on the property of James and Joseph 
Forgy, one mile southwest of Vineyard by John S. Bare & Com- 
l)any. Works were erected and operated. This plant was operated 
during th^ year following under various names, among them Bare 
& Walton, and Walton & Fleming, and was finally in 1896 merged 
into the Crystal Sand Company, of which the largest stockholders 
are the former partners. These works are still in operation. 

In 1892 an opening was made a short distance southwest of the 
Crystal Sand Company's plant. After some prospecting, quite a 
large sand crusher and flint mill was erected. The parties inter- 
ested were from Wellsville, Ohio, the manager being W. 8. Steven- 
son. The business was not successful and after some years of opera- 
tion under the name of Juniata Silica Company, the works were 
closed, dismantled and the property sold. 


In 1912 the Pennsylvania Glass Sand Company erected a large 
cmshing and grinding plant between Ryde and Vineyard station, six 
miles southwest of McVeytown, The buildings are of brick, concrete, 
and steel. This plant has a capacity of 600 tons of washed sand and 
a drying capacity of 400 tons. Power is electric and steam. The 
sand is largely mined by the hydraulic system. The harder rock en- 
countered is put through a jaw crusher and chaser mill. 

While there have been quite a large number of other sand properties 
opened up beside those mentioned, they have all been abandoned on 
account of an inferior quality of sand, or on account of poor location 
with respect to shipping facilities. For the above account of the 
glass sand industry of Mifflin county the writer is indebted to Mr. W. 
P. Stevenson of McVeytown. 

Description of Glass SaDd Quarries and Plants at Present in Operation 

Dumg the sununer of 1914 there were two companies producing 
glass sand in Mifflin county and one operator who was installing the 
machinery necessary to wash sand for the glass industry. The two 
companies referred to are the Pennsylvania Glass Sand Company and 
the Crystal Sand Company. John Miller, of Lewistown, was in- 
stalling equipment to prepare some glass sand for his mine northeast 
of Bumham. The Pennsylvania Glass Sand Company operates three 
plants in Mifflin county, namely, one at Granville known as the 
Juniata Works, and two at Vineyard known as the Hatfield and En- 
terprise Works respectively. The Crystal Sand Company has one 
plant at Vineyard. 

Juniata Works of the Pennsylvania Glass Sand Company. 

The Jimiata Works of the Pennsylvania Glass Sand Company is lo- 
cated on the west bank of the Juniata River about three and three- 
fourths miles southwest of Lewistown. It is connected with the 
main line of the Pennsylvania railroad by a spur which joins the 
former near the station of Granville. The mine which supplies this 
plant with sand is located about 2700 feet northwest of the plant, 
in a synclinal ridge which rises about 500 feet above the level of the 
river and trends in a northeast and southwest direction. 

Figure 1, Plate LVIII, shows a cross section of the ridge and the 
position of the Oriskany outcrop on it. As has already been stated 
in a previous paragraph the northwest limb which crops out at the top 
of the ridge has undergone very little change and is still a white 
hatd quartzite. The southeast limb on the other hand has undergone 
considerable disintegration, so that it now consists entirely of loose 
white sand and very friable sandstone. An analysis of this sand 
showed .11% FejOj. A screen analysis showed that it is made up of 
the following sized grains: 


Passed through a ID mesh sieve, caught on a 14 mesh (.046 Inches), .01 

Passed through a 14 mesh sieve, caught on a 20 mesh (.0328 inches). .28 

Passed through a 20 mesh sieve, caught on a 28 mesh (.0232 inches), 1.31 

Passed through a 28 mesh sieve, caught on a 35 mesh (.0164 inches), 5.15 

Passed through a 35 mesh sieve, caught on a 48 mesh (.0116 inches), 20.77 

Passed through a 48 mesh sieve, caught on a 65 mesh (.0082 inches). 36.80 

Passed through a 65 mesh sieve, caught on a 100 mesh (.0058 inches), 24.32 

Passed through a 100 mesh sieve, caught on a 150 mesh (.0041 inches), 5.14 

Passed through a 150 mesh sieve, caught on a 200 mesh (.0029 inches), 2.91 

Passed through a 200 mesh sieve -2.28 


The formation is 100 feet thick at the mine and dips 42^*^ to the 

The present tunnel, which is about 140 feet above the level of the 
river and 1200 feet long, cuts the sandstone at a depth of about 220 
feet below the surface. From this tunnel a gang way has been run in 
the sandstone along the hanging wall for a distance of 1100 feet to 
the northeast and 1500 feet to the southwest. Foiiy feet above the 
gangway a drift has been run parallel to it and also next to the hang- 
ing wall, with chutes eveiy 200 to 300 feet to connect it with the 
former. Plate LXXXV, shows the method of mining employed to 
obtain the sand. An old tunnel which cut the sandstone 90 feet 
above the level of the present main gangway was employed to mine the 
sandstone above that level, so that there are about 40 feet of sandstone 
between the present upper drift and the abandoned workings above. 

The main gangway is 8 feet wide at the bottom, 5^ feet at the top, 
and 6 feet high. The upper drift is 7 feet wide at the bottom, 4^ 
feet at the top and 6 feet high. Rooms are driven from the upper 
level across the formation to the footwall every 15 feet. These rooms 
are of the same width and height, when first driven, as the level itself. 
They are then gradually widened and increased in height from the 
footwall toward the hanging wall as shown in the illustration. The 
men stand on the loose sand and broken sandstone in the rooms to 
drill and shoot dftwn the rock overhead. From one-half to two-thirds 
of the sand present is recovered. In the rooms the sand is loaded 
into cars which are trammed by hand to the chutes along the upper 
level. The sand from these chutes is then allowed to run into cars 
in the main gangway below and is hauled to the mouth of the tun- 
nel by mules. From there it is hauled to the washing and drying 
plant by a small steam locomotive. A great deal of timber is re- 
quired in the drifts and rooms. The sand is mostly loose and at 
times, when it is saturated with water, runs almost like quicksand. 
A great deal of difficulty was experienced when the lower tunnel was 
first driven on account of the water in the abandoned upper workirffes. 
This had to be drained oflf. 

The sand as it comes from the quarry is already a loose white sand 
containing only a few lumps of friable sandstone which crumble 
readily to sand between the fingers. No crushing machinery is, 


therefore, required at the Juniata Works, the sand being simply 
screened and then sent directly to the screw washers. A Cummer dryer 
is used to dry the sand. Plate LXXXVl shows the flow sheet of the 
mill. The washing plant has a capacity of 125 to 135 tons of sand 
per day of ten hours, while the Cummer Dryer has a capacity of 120 
tons. A pulverizing miU is located at this plant in which part of 
the sand is pulverized in tube mills to a fine powder. The greater 
portion of the output of the Juniata Works of the Pennsylvania Glass 
Sand Company consists of an excellent grade of No. 1 glass sand, 
due to the fact that the sand as it comes from the mine consists of 
practically nothing but quartz grains and contains almost no iron 

Hatfield Works of the Pennsylvania Glass Sand Oompany. 

The Hatfield works of the Pennsylvania Glass Sand Company are 
situated along the west side of the Pennsylvania railroad about one 
mile northeast of Vineyard. This quarry is located on a portion of 
the Oriskany sandstone which is an erosion remnant preserved along 
the axis of a syncline. It forms at this place the cap rock of a syn- 
clinal ridge which rises about 350 feet above the level of the Juniata 
Valley, and can be followed for a distance of 1500 feet in a northeast 
direction from the quarry. The river in making a broad curve has 
cut back beyond the axis of the syncline thus exposing the sandstone 
in a favorable position for quarrying. Figure 2, Plate LXXXIV 
shows the plant and the quarry back of it. 

The rock is badly fractured as is shown in Figure 1, Plate LXXXIV. 
Disintegration along the joints thus developed has been pronounced 
so that large quantities of loose sand are present and the sandstone 
between them is friable that it crumbles readily to sand between the 
fingers. The sand along the joint planes is, as a rule, discolored 
somewhat by limonite, but the writer was informed that No. 1 sand 
can be made from it by washing. The sandstone itself is usually 
white and shows very little iron stain. An analysis of a representa- 
tive sample of the loose sand found in the quarry shows the presence 
of .17% FcsOg. Another sample of sand which had been washed 
to the foot of the quarry contained .16% FejOg. An analysis of the 
No. 1 glass sand produced at the Hatfield works indicated the pres- 
ence of .06% FejOi,. Screen analysis of the loose sand from the 
quarry and the No. 1 sand gave the following results : 

Passed through 10 mesh, caught on 14, 36 

Passed through 14 mesh, caught on 20. 1.26 .05 

Passed throutrh 20 mesh, caught on 28, 8.04 1.23 

Passed through 28 mesh, caught on 85 7.45 4.88 

Passed through 35 mesh, caught on 48 35.82 84.80 « 

Passed through 48 mesh, caught on 65. ._ 88.51 41.08 

Passed through 65 mesh, caught on 100. 11.09 15.04 

Passed through 100 mesh, caught on 150 2.38 2.09 

Passed through 150 mesh, caught on 200 1.55 .49 

Passed through 200 mesh 3 30 .16 

99.26 99.77 





The present quariy face is about 150 feet wide at the base and 
100 feet high with a slope of 3Gi°. Most of the sand is sufficiently 
loose so that it can be washed down the face of the quarry into flumes 
which carry it to the mill, by turning a stream of water under pres- 
sure on it. The boulders oi less disintegrated sandstone accumulate on 
the slope near the base, and from time to time are loaded into cars 
and are taken to the mill to be crushed. Occasionally a blast is set 
from holes drilled down from above, back of the quarry face, to loosen 
large quantities of rock. 

At the Hatfield Works all of the No. 1 .sand is put through a nine 
foot chaser mill before it is washed. Steam dryers are employed for 
drying. Plate LXXXVII shows the flow sheet of the mill. This is 
one of the most up to date and the largest sand plant at present 
operated in the State. It has a daily capacity of 600 tons of washed ^ 
sand and a drying capacity of 400 tons. The building in which the 
mchinery is housed is of brick, concrete, and steel construction. The 
drainage room has a capacity of 4500 tons.- At present the sand is 
shoveled by hand from the draining floor onto belt conveyors which 
carry it to the steam dryers, but the intention is eventually to install 
a traveling crane and scoop to accomplish this. The mill is equipped 
with radiators and steam pipes to prevent the wet sand from freezing 
in the chaser mill, screw washers, and on the belt conveyors during 
the winter months. Exhaust steam is used for this purpose. The 
machinery can be operated either by steam or electric power. The 
dry sand is conveyed through pipes underneath the hopper bottom 
bins into cars so that no hand labor is required in loading. A pul- 
verizing mill is operated in connecton wth the plant. 

Enterprise Works of the Pennsylvania Glass Sand Company. 

The Enterprise Works of the Pennsylvania Glass Sand Company ia 
located on a short siding at the station of Vineyard, on the Pennsyl- 
vania railroad. The quarry is situated a short distance to the north- 
west in a body of Oriskany sandstone dipping 20° to the southwest, 
which foiTOS the northwest limb of a syncline at this place, and which 
is the southerly extension of the southwest pitching syncline on which 
the Hatfield Quarry is located. 

The sandstone is badly fractured and disintegration along joint 
planes is pronounced. Unfortunately the loose sand thus formed 
has been stained with limonite to such an extent that it is only avail- 
able for No. 2 glass sand. The masses of less disintegrated rock a^ 
a rule are white and comparatively free from iron, so that they yield 
a^\). 1 sand. The sandstone outcrop forms a low ridge on the side of 
a gently sloping hill underlain by shale and limestone, which rises to 
the northAvest of the Juniata Valley at Vineyard. 

The sandstone is cut by a tunnel through the overlying shales at 






00 f 



5 f*. 


^ >j 3) ^ 

3 - 















1'1-\T1-: LXXXVlll 

Fie- n. Vii-w InokinB soutliwpst in nbiivf quarry. 





^0 fNj 

C33 ^ 



^ Co 

























1-iii IlitHu'v. T.ili'svillc. 



!5 I 

cm ff ~« 1 


a depth of about 125 feet below the outcrop. No underground min- 
ing is done, however the deposit being worked as an open quarry. 
The formation has been opened for a distance of 670 feet along the 
strike. The southwest 520 feet have been worked in two benches, 
the upper bench^ with a maximum depth of about 75 feet, was taken 
out before the present tunnel was driven. This cut the sandstone 
50 feet further down and about 190 feet of sandstone along the strike 
at the northwest end of the upper bench have been mined to this 
new level. The northeast 150 feet of quarry have been worked as 
^one bench. The quarry has a width of 180 feet at the top at tile north- 
east end, and 240 feet at the southwest. Figure 1, Plate LXXXVIII 
shows a view of the quarry looking northeast, Figure 2 one in the cen- 
tral portion, and Figure 3 one looking southwest. 

The sandstone and sand are loaded into cars at the quarry and 
hauled to the mill by mules. The mill is equipi)ed with three six 
foot chaser mills, and a steam dryer. Plate LXXXIX gives the flow 
sheet. It has a daily capacity of about 240 tons of sand. Only the 
sandiE^one can be used for preparing No. 1 sand, the loose sand con- 
taining so much limonite that it yields only No. 2 sand No. 3 grades. 
About one-third of the output of the quarry is sold as No. 1 sand, the 
balance being Nos. 2 and 3. The No. 3 sand is not passed through 
the dryer but is sold wet. 

Crystal Sand Company. 

About one mile southwest of the station of Vineyard on a short 
siding of the Pennsylvania railroad, the Crystal Sand Company is 
operating a sand plant of 200 tons daily capacity. The quarry is 
situated at the works on the same limb of the syncline on which the 
Enterprise quarry is located. The dip is a very gentle one toward 
thiB southwest. The rock encountered in this quarry is moderately 
hard, it being possible to disintegrate it only with difficulty between 
the fingers. The rock is badly fractured and some iron oxide stain 
occurs along practically all the joints thus developed, but does not 
penetrate the rock itself to any extent. The upper 8 feet or so of 
the formation contain large amounts of limonite and together with 
about two feet of soil have to be stripped. This is done by loading 
the material into wagons and hauling it to abandoned portions of 
the quarry or other places off of the outcrop that are convenient. The 
present working face is about 300 feet long and 30 feet high at the east 
end and 50 feet at the west. Figure 1, Plate XC shows a view taken 
in the quarry. 

The plant is equipped with two chaser mills and the necessary jaw 
crushers, screens, screw washers, conveyors, etc. For preparing the 
sand a steam dryer is used for drying the sand. Plate XCI shows 
the flow sheet of this mill. 


John Miller's Sand Mine at Burnham. ' 

During the summer of 1914, John Miller, of Lewistown, erected a 
small sand washing plant on KishickoquiUas creek below Burnham 
to treat sand obtained from his mine about one mile northeast of this 
place. Loose sand is mined and therefore, no crushing machinery 
is necessary. Mr. Miller does not intend to dry any sand at first, 
but expects to sell it wet. Later on if he opens up considerable 
bodies of first class sand in his mine a dryer may be installed. The 
washing plant and mine are connected by a narrow gauge track, over 
which cars are run by a small electric motor. 

The mine is located on the southeast limb of a syncline, the strata 
dipping gently to the northwest as is shown in Figure 1, Plate 
LXXXllI which is a cross section of the ridge in which the mine is 
situated. A tunnel has been driven into the hill for about 700 feet 
through the underlying shales to cut the sandstone at a depth of about 
100 feet below its outcrop. 

The sandstone of this limb of the syncline has been disintegrated 
to loose sand by the agents of weathering. As exposed in the^ved 
openings along the outcrop over the mine workings it is seen to be 
a light yellowish brown in color and appears as though it ought to 
yield a No. 2 glass sand on washing. An analysis of a sample ob- 
tained here gave .18% Fe^Os. A size determination of the grains 
gave the following results : 

Screen Analysis of Sand from John Miller's Mine, Burnham. 


Passed through a 14 mesh and caught on a 20 mesh sieve, 0828 .02 

Passed through a 20 mesh and caught on a 20 mesh sieve. .0232 .21 

Passed through a 28 mesh and caught on a 35 mesh sieve, .0164 1.13 

Passed through a 35 mesh and caught on a 48 mesh sieve .0116 10.48 

Passed through a 48 mesh and caught on a 65 mesh sieve. 0082 56.76 

Passed through a 65 mesh and caught on a 100 mesh sieve. .0058 25.43 

Passed through a 100 mesh and caught on a 150 mesh sieve. .0041 2.64 

Passed through a 150 mesh and caught on a 200 mesh sieve. 0029 1:30 

Passed through a 200 mesh. 1.58 


During the winter of 1914 the writer was informed by the officials 
of the McEee Glass Company of Jeannette, that they had used two 
carloads of sand from John Miller's plant and found it entirely sat- 

Undeveloped Areas. 

One of the most promising occurrences of Oriskany sandstone in 
Mifflin Gk)unty which is not as yet utilized for glass sand is the one 
opened up in the sand pit of the Standard Steel Company about 2 
miles northeast of Burnham. Unfortunately there is a large amount 
of overlying shale and iron stained sandstone, so that underground 
mining methods would probably have to be used to recover the white 
sand. Most of the other outcrops of Oriskany in the area around 


Lewistown, with the exception of the occurrence northeast of Bum- 
ham, do not look very promising. 

Bodies of white sandstone suitable for glass sand undoubtedly oc- 
cur between the Juniata Mine at Granville and the Dull Mine at Mc- 
Veytown. Some of this' ground is already under the control of the 
Pennsylvania Glass Sand Company, including onfe and one-half 
miles of out crop northeast of the Dull mine, which this Company 
expects to open up as soon as better railroad transportation facili- 
ties are available. 

Southwest of the Dull & Macklin mines the outcrop also has a 
favorable appearance, especially beyond the creek which crosses the 
outcrop on which the former are located, two miles southwest of Mc- 
Veytown. A great diflSculty here is the poor facilities for transpor- 
tation, as this portion of the outcrop is located at a considerable dis- 
tance from the railroad. 

At Vineyard practically all the available sites for quarries are al- 
ready utilized. On the whole the disintegrated sandstone in this 
vicinity contains a little more iron in the form of limonite than that 
at the other glass sand producing centers of the Juniata Valley, and 
it also becomes fairly hard southwest of Vineyard where the forma- 
tion lies nearly horizontal. 





Bedford County. 

The outcrop of Oriskany sandstone along Warriors Ridge, in Hunt- 
ingdon County', has already been described in a previous chapter deal- 
ing with the Oriskany of that county. This outcrop continues in 
a southwesterly direction through the whole length of Bedford County. 

It was examined in some detail by the writer between Tatesville 
and Everett, where it has undergone considerable disint^ration, and 
in many places crumbles readily to white or light yellow sand. 

At Tatesville, which is about 3 miles north of Everett, a small 
stream has cut a gap across the Oriskany outcrop. The sandstone 
has a thickness of about 100 feet at this place and dips 30® to the 
southeast. The part which is well exposed here is a hard white 
quartzite, containing comparatively little iron oxide. South of this 
gap, however, portions of -it begin to show disintegration, whch be- 
comes more and more pronounced as the outcrop is followed away 
from the creek. The rock is free from iron stain and where it has 
disintegrated to sand this is almost white in color. 

About one-half mile south of the gap at Tatesville, Calvin Ritchey 
has opened a quarry on land belonging to the Huntingdon & Broad 
Top Mountain Railroad and Coal Company. The sandstone at this 
place has, for the most part, been disintegrated to loose sand, varying 
in color from white to light yellow. An analysis of an average 
sample of unwashed sand from this quarry gave .10% Pe,Oj. A 
sizing test gave the following results. 

Screen Analysis of Sand, Ritchey Quarry, Bedford County. 

Passed through 10 mesh and caught on a 14 mesh sieve, '.046 .11 

Passed through 14 mesh and caught on a 20 mesh sieve, .0328 .74 

Passed through 20 mesh and caught on a 28 mesh sieve .0232 3.27 

Passed through 28 mesh and caught on a 35 mesh sieve, .0164 10.56 

Passed through 35 mesh and caught on a 48 mesh sieve, .0116 37.35 

Passed through 48 mesh and caught on a 65 mesh sieve 0082 33.47 

Passed through 65 mesh and caught on a 100 mesh sieve, .0058 10.59 

Passed through 100 mesh and caught on a 150 mesh sieve — .0041 1.35 

Passed through 150 mesh and caught on a 200 mesh sieve 0029 .64 

Passed through 20O mesh sieve 1.45 


This quarry has been opened for a distance of 150 feet along the 
strike and has a maximum height of 35 feet, with 1 to 2 feet of soil 
covering the sand. The ridge, on the west side of which the quarry 
is located, rises about 65 feet above the bottom of the quarry and on 
the quarry side has a slope of 28°. The formation drops 30° to the 
southwest, Figure 2, Plate XC shows a view looking north in this 



At present the sand is mined with picks and shovels, and is loadeti 
into wagons which haul it 200 feet to a siding on the Himtiugdon & 
Broad-Top Mountain Railroad. Boulders of sandstone which are 
encountered are crushed into sand with hammers. The sand is sold 
largely to the Colonial Iron Company of Riddlesburg, the Earlston 
Furnace at Everett, and the Sax ton Furnace at Saxton, for furnace 
sand. Some is also used locally for concrete. None of it is being 
sold for glass sand at present, although a good quality of glass sand 
could be produced from it by washing and drying. 

Sand was at one time t^ken from this locality for an old glass 
works at Everett. It was used without washing or drying, and there- 
fore was not found satisfactory, and sand was imported 
from Mapleton instead. Mr. H. F. Gump of Everett, who 
was interested in this glass works informed the writer that 
the sand they took out contained too much iron. It is very 
likely they happened to make an opening at a place where some iron 
bearing solutions had filtered in and locally precipitated limonite in 
the sandstone. Practically all the sand exposed in the present work- 
ing face could on washing and drying be sold as No. 1 sand. Oc- 
casionally a little iron oxide has been brought in along a joint plane 
but this forms a relatively insignificant percentage and could be 
readily sorted out^ 

About 100 feet south of the above quarry is another one which 
has been opened for a distance of about 550 feet along the strike, 
with a maximum height of working face of 35 feet. Most of this 
sand as exposed is also either white or else only a light yellow in 
color and apparently of excellent quality. At several places some 
limonite has been deposited locally in the sand by circulating waters. 

One and one-half miles south of Tatesville, along the ridge formed 
by the Oriskany outcrop, the sandstone has been uncovered for a 
short distance and some of it has been quarried for use in building 
a reservoir on the side of the ridge at this place. The rock is white 
in color and only moderately hard, resembling the sandstone at the 
Keystone and Columbia quarries at Mapleton in these respects. About 
one-fourth of a mile further to the south an opening about 500 feet 
long partially expose the Oriskany sandstone along its outcrop. As 
far as can be seen the sandstone has been disintegrated to loose sand 
and is comparatively free from iron oxides, so that it is practically 
white in color. 

About one-half mile south of the above opening and one mile north 
of Everett, another sand pit has been opened along the Oriskany 
sandstone to supply the local demand for building sand. This pit 
is about 90 feet long and has an average depth of 20 feet. The ridge 
rises 60 feet above the bottom of this quarry and has a slope of 28^° 
on the west side in which the quarry is located. The sandstone dips 


45** to the southeast. All of it crumbles readily to white or light yel- 
low sand. Only occasionally is a little iron stain present along joint 
planes. From outcrop incUcations it appears that the upper por- 
tion of the formation, which has not been opened up as yet, is some- 
what harder and less disintegrated. 

Although no glass sand had been prepared from the Oriskany sand- 
stone between Tatesville and Everett up to the time of the writer's 
visit in 1914, with the exception of a little for local use at a former 
glass works in Everett, excellent deposits of such sand are available 
at this locality. The only disadvantage is that in shipping to west- 
em Pennsylvania the sand would have to be sent over two railroads, 
namely, the Huntingdon & Broad-Top Mountain, and some other 
line, to destination which would involve higher freight rates than 
from points more favorably located. 

Blair County. 

According to Franklin Piatt ** the Oriskany sandstone reaches a 
thickness of only 20 to 50 feet in Blair county. It is highly fossilif- 
erous and usually friable, decomposing rapidly into loose sharp sand 
at the surface. Piatt reports the occurrence of a fine deposit of 
glass sand on the poor house farm one mile northwest of Hollidays- 
burg. The sand is clean and sharp and has been used for foundry 
purposes. This locality was not visited by the writer. 

Carbon County. 

Prof. B. L. Miller*' in describing the Oriskany of Carbon County 
states that it consists of sandstone and conglomerates of resistant 
character that are responsible for Stony Ridge. These sandstones 
and conglomerates vary in thickness from 150 to 175 feet. The 
cementing material in mainly calcareous and its removal in many 
places has caused the rock to disintegrate. Sand quarries are abund- 
ant all along the ridge for many miles, the material being shipped 
to many point in the State for use as molding sand, concrete and other 
purposes. The silica frequently runs as high as 98%. In working 
the sandstone for>iand, the places where the rock is most greatly 
decomposed are selected, and little crushing is. required. The sand 
grains are usually well rounded. The color is white to light yel- 

Centre County. 

In Centre County according to E. V. d'lnvilliers^* the Oriskany 
sandstone has a maximum thickness of not exceeding 130 feet. Ah 
outcrop occurs along the southeast margins of Boggs, Howard and 
Liberty townships, dipping toward the northwest at an angle of from 

R4. Second Oeoloirlcal Snnrey of Pennsylranla Report T. 1881, pp. 8B-ft6. 
BS. Toposrraphlc and Oeolojflc Snrvey of Pcnniylranfa Report No. 4, pp. 62-55. 
66. Second Oeoloffical Surrey of PennsylTanla Report T-4, pp. 202-203. 


20 to 40^, which according to d'Invilliers, has weathered to friable 
white sandstone and loose sand suitable for glass working at a num- 
ber of places. It was at one time quarried for this purpose to sup- 
ply a glass works at Bellefonte. 

Monroe County. 

According to I. C. White*^ sand for glass working was at one time 
quarried from the Oriskany formation of Monroe county, in Hamilton 
township. Glass sand was for a long time obtained from the Oris- 
kany on the summit of Godfrey's Ridge for a bottle glass factory at 
East Stroudsburg. The rock is a grayish white, rather coarse 
grained sandstone with many small pebbles, which have a darker ap- 
pearance than the enclosing matrix. The rock was hauled seven 
miles to East Stroudsburg. It contained too much iron for window 
glass. There are a number of other places along the ridge where 
sand for bottle glass has been obtained. The formation has a thick- 
ness of from 160 to 200 feet 

57. Second Oeoloflcal Bnrrej of PenoiylTanU, Beport 0-6, pp. S88<284. 




The Pottsville formation comprises the lowermost of the four for- 
mations into which the upper Carboniferous or Pennsylvania strata, 
of western Pennsylvania have been divided, the others being the Alle- 
gheny, Conemaugh, and Monongahela respectively. It is composed 
of conglomerates, sandstones, shules, clays, including fire clays, coals 
and limestones, with conglomerates and sandstones predominating. 

Character and Distribution of the Pottsville Formation. 

The Pottsville group has a widespread distribution over a large por- 
tion of the Appalachian mountain and plateau provinces of the East- 
ern United States. It underlies the anthracite coal measures of 
eastern Pennsylvania and the later Pennsylvanian strata of western 
Pennsylvania and adjoining parts of eastern Ohio, and extends south- 
west through Mar^iand, West Virginia, Virginia, Kentucky and Ten- 
nessee into northern Georgia and Alabama. 

The group received its name from the town of Pottsville, which is 
situated near the center of the Southern Anthracite Coal Field of 
Eastern Pennsylvania, in Schuylkill County. In this vicinity it 
reaches a tftal thickness of 1200 feet. At its base it is apparently 
conformab!(^ with the Mauch Chunk shales of the Mississippian, or 
Lower Carboniferous Period, the latter grading into the former 
through the gradual intercolation of more and more conglomerate 
beda On top, the line between it and the overlying coal measures 
has been drawn at the lowest workable coal in the type region at 
Pottsville,, known as the Twin or Buck Mountain bed'*. The con- 
glomerates in the lower portion of the Pottsville formation are pre- 
vailingly greenish, feldspathic, and poorly cemented. Cross bedding, 
indicative of current movement from the northeast, is conspicuous. 
The relatively small amounts of shales and coaly matter in the type 
section are for the most part contained in the middle third. Toward 
the top the conglomerate material becomes lighter in color, on ac- 
count of the predominance of quartz grains and pebbles. At the type 
section near Pottsville a few thin coals occur in the formation, none 
of which, however, are profitably workable. To the north of Potts- 
ville on the other hand, on Broad Mountain, and to the west through 
out the Southern Anthracite Field, coals occur in greater develop- 
ment, especially locally, and have been extensively mined. These 
are known as the Lykens coals. Sometimes as many as six distinct 
beds are present. David White has divided the Pottsville of the 

58. David White. 20th Annual Report of the United States Oeoloflcml Svrrer. Put H. 1898-90. 


Southern AJithracite Field into four parts, namely : a Lower Lykens 
group, a Lower Intermediate division, an Upper Lykens group, an 
Upper Intermediate division, on the basis of the fossil flora found as- 
sociated with these coal beds. 

To the northward the Pottsville gradually becomeis thinner. In 
the Western Middle Anthracite Field the average thickness is about 
850 feet*^*. Near the western end of the field two workable coal 
beds occur in the formation. In crossing the Eastern Middle Field 
from the south toward the northeast, the Pottsville diminishes in thick, 
ness from 500 feet to about 200 feet. It also shows a decrease in the 
size of the materials composing it. The one coal bed found here 
in the conglomerate has locally a workable thickness. In the North- 
em Anthracite Field the formation has an average thickness of about 
225 feet, but is thinner at either end than in the central portion of 
the field. The diminished coarseness of the material is very marked, 
and toward the northeast end of the field the pebbles in the conglom- 
erate are much scattered and rarely exceed pea size. No coal beds 
of workable thickness are found. At Campbell Ledge, near Pittston, 
in the Northern Anthracite Field, the formation has a thickness of 
only 56 feet, and at its base, according to David White, contains a 
flora which is similar to that of the Upper Intermediate division of the 
Southern Field, The three lower divisions, therefore, are not repre- 
sented here. 

In the Broad-Top coal field of Huntingdon and Bedford Counties 
in South Central Pennsylvania, according to James H. Gardner *° the 
Pottsville has a thickness of 192 feet and consists mostly of sandstone, 
with some interbedded carbonaceous shales which contain thin streaks 
of coal. 

Section of the Pottsville In the Broad Top Coal Fields. 

Sandstone (Homewood) hard, medium grained, mlscaceous, gray, but 

weathers reddish brown, ., 45 

(Mt. Savage or Mercer Horizon ?) 2 

Shale bituminous, carrying kidney-shaped siderlte concretions In upper 

portions, «- _ 80 

Sandstone (Oonnoquenessing?), hard, medium grained, micaceous, gray 

but weathers reddish brown 80 

Shale, carbonaceous with streaks of coal (Sharon?) I 1 

Sandstone, brown, gray, and greenish gray 84 

Concealed, probably samlstone, 25 

Sandstone, gray, -containing white quartz pebbles less than one Inch 

In diameter .v jq 

Sandstone, similar to above, with thin layer of conglomerate lenses. -..I 15 


The lower sandstone comes to rest with a disconformity on the 
Mauch Chunk shales of the upper Mississippian, indicating an erosion 
interval between the two. 

W;,8«wnd O«oloflcal Surrey of PennsylTtnla. Pinal Report, Vol. 8, Part I. pp. 1808-1864. 
pp. 755-030. 

60. Topofrraphle tod G«oIofflc Surrey of Peiui§ylTtii!t, Report 10. 1018. p. 26. 



In the central part of northern Pennsylvania, in Tioga and Potter 
counties, the Pottsville has a thickness of 260 to 300 feet according 
to M. L. Puller*^ and can be divided into two members, the lower of 
which consists of 60 to 100 feet of white quartz conglomerate and 
sandstone, black shale, and fireclay with a three foot coal bed in the 
upper part. The lower member has been called the Glean or Sharon 
CJonglomerate. The Olean conglomerate, from paleobotanic evidence, 
is known to belong to the upper division of the Pottsville of Eastern 
Pennsylvania. The fossil plants associated with the coal bed in the 
upper part of the formation indicate that the bed belongs to the Mer- 
cer horizon of the Pottsville. The Olean conglomerate lies discon- 
formably upon the Mauch Chunk shale of the Mississippian Period. 
The Pottsville is the highest formation left by erosion in this area. 

In Warren County^* in northwestern Pennsylvania, the Pottsville 
has been divided into three members, namely : — a lower one known as 
the' Olean conglomerate, a middle one called the Sharon shale mem- 
ber, and an upper one called the Connoquenessing sandstone. The 
Olean is a coarse conglomerate, being composed almost everywhere 
of well rounded pebbles of white quartz, ranging up to 2J inches in 
diameter, though for the most part measuring 1| inches or less. These 
pebbles are imbedded in a fine groun'd mass of quartz grains and are 
cemented by iron oxide and silica. This bed rests unconformably 
upon the Mississippian strata underneath, with overlap towards the 
north. The Sharon shale member consists of about 40 feet of dark 
shale with limonite nodules and a few thin sandstone layers. One 
or two thin seams of coal are also present. The Connoquenessing 
is uniformly a very coarse, saccharoidal, white quartz sandstone, with 
a few small pebbles in places. Poorly preserved plant stems are com- 
mon in it. It reaches a thickness of about 100 feet in places, while 
sometimes it thins down to 20 feet or even less. 

The Olean conglomerate does not extend as far south as Clarion 
County. In this county the Connoquenessing member comes to rest 
unconformably upon upon Mississippian strata. It is thick bedded, 
persistant, saccharoidal sandstone, which ranges in color from buff 
to white and is nonfossiliferous*''^. Some layers are not well consoli- 
dated and appear much like granulated sugar. On the whole the 
rock is very clean and free from everything but silica. The beds are 
more or less lenticular. In thickness the Conoquenessing sandstone 
ranges from 30 to 50 feet. Above it, in Clarion County, is a series 
of shales, thin coals, and clays which has received the name of Mercer 
shale, because in Mercer county these beds are a prominent part of 
the section and one of the coals is worked. In Clarion County it 

61. United States Oeologrlcal Surrey, Polio 92, 1903. 

62. UnltM SUtes Oeologlcal Surrey Folio 172, 1910. 
68. United States Geological Surrey, Folio 178, 1911. 


varies in thickness from 6 inches to 40 feet. The topmost member 
of the Pottsville in Clarion County is the Homewood sandstone, which 
averages about 40 feet in the thickness. In some cases, however, the 
member is represented by shale. As a rule, it is a clean, white, finely 
cross bedded, and loosely cemented sandstone. 

The following section of the Pottsville has been measured by I. C. 
White in Mercer County in Western Pennsylvania'*: ^ 

Pottsville Section in Mercer County. Pennsylvania. 


Homewood sandstone, ., - 60 

Shales, - — 6 

Iron ore, — 2 

Mercer limestone (contains marine fossils), -. — 21 

Mercer upper coal 2} 

Shales 25 

Iron ore, — 2 

Mercer lower limestone (marine mollusca), - 2| 

Shales 10 

Mercer lower coal, - — 2| 

Shales — _ 10 

Iron Ore - . 1 

Shales, - ^ 6 

Upper Connoquenessinff sandstone * . 40 

Shales with iron ore, , 10 

Quakertown coal, — .- 2 

Shales ^ 40 

Lower Connoquenessing sandstone, - 80 

Sharon iron shales, . 80 

Sharon coal, 4 

Fire clay and shales, 5 

Sharon conglomerate, - 20 


In northern Ohio'* conglomerate, or coarse grained sandstone, which 
has generally been called the Sharon conglomerate, and which is per- 
haps equivalent to the Olean conglomerate of southwestern New 
York and northwestern Pennsylvania, lies at the base of the Potts- 
ville. On top follow the Sharon coal, the lower and upper Massilon 
sandstones, the lower and upper Mercer groups, and the Homewood 
sandstone. Dr. J. J. Stevenson regai^ds the Massilon and Connoque- 
nessing sandstones as equivalent. 

Returning to Blair county in south central Pennsylvania, north- 
west of the Broad-Top mountain coal field, the Pottsville formation 
lies unconformably upon the Mauch Chunk shale of the upper Mis- 
sissippian, and has a thickness of about 130 feet**. It is composed 
of two sandstone members separated by shale and fire clay. These 
are the Connoquenessing sandstone, the Mercer shale and clay, and 
the Homewood sandstone. The Connoquenessing member in this 
section is 80 to 100 feet thick and consists of a rather coarse, gray 
sandstone with small lenses or layers of gray sandy shale. Above 
the Connoquenessing are 5 feet of shale overlain by 9 feet of fire clay, 
at the top of which, partially included in the overlying Homewood 

64. Second Qeoloi^fcil Surrey of PenDsylTania Report 0-8, 1880, p. 88. 
66. OeoIofTlcal Snrrey Ohio. Bulletin No. 7, Fonrtn Series. 
66. United Statei Oeolofflcftl Surrej, Folio 188. 


sandstone, are small pockets of coal, 2 inches thick. Above the fire 
clay is the Homewood sandstone, coarse, massive and 15 feet thick. 
Neither the Connoquenessing nor the Homewood sandstone is con- 
glomeratic in this section. 

In southwestern Pennsylvania, in Fayette county'^ the Pottsville 
formation has a thickness of about 180 feet and can also be divided 
into three members, namely: — the Connoquenessing sandstone, the 
Mercer coal and shale, and the Homewood sandstona The Conno- 
quenessing sandstone rests disconformably upon the Mauch Chunk 
shales. It is usually less than 100 feet thick in this area. In places 
it is a coarse conglomerate, but generally it is a coarse, irregularly 
bedded sandstone. It frequently contains lenses of shale. The 
Mercer shale member varies from 20 to 50 feet in thickness. Irregu- 
lar beds of sandstone occur in the shale and usually a thin streak of 
coal. A study by David White of the fossil plant remains from this 
horizon has shown that this coal is the equivalent of the Mount Sav- 
age coal of Maryland. The Homewood sandstone ranges in thick- 
ness from 30 to 80 feet. The upper portion is generally conglom- 

In western Maryland at Swallow Falls'" in Garret county, the fol- 
lowing section of Pottsville is exposed: 

Section of PottSTllle at Swallow Falls. Maryland. 

Feet. Inches. 

Massive sandstone (Homewood), .. 50 

Fire clay (Mount Savage) - - 4 

Coal (Mount Savage), 3 

Shale _ 5 

Sandstone - 5 

Coal (Lower Mercer), >. ,;. 10 

Conglomeratic sandstone (Upper Connoquenessing, 15 

Black Shale _ 2 

Coal (Quakerstown), — - -. 1 6 

Shale 6 

Concealed. - - — - 8 

Massive conglomerate sandstone (Ivower Connoquenessing), .15 

Concealed 60 

Shale, - 5 

Coal (Sharon) 1 4 

Shale - 6 

Sandstone — 25 

m 4 

Along Cheat River, in Preston County, in northern West Virginia, 
the following section of Pottsville has been measured by I. C. White**: 

Section of Pottsville in Preston County, West Virginia. 

Feet. Inches. 

Sandstone, massive (Homewood), .- 60 

{Coal, feet 5 inches, 1 

Shales, sandy, 6 feet Inches. \ 6 10 
Coal, 4 feet 5 inches. J 

Shales, brown, sandy, 45 

Coal, slaty 2 

Shales 3 

67. United States Geoloprlcal Smrej, FoUo 82. 

68. MarxUnd Geolorical Surrer, Geolocr of Garrett Cowaty, ] 
60. WMt Virginia Geological Barrej, Beports, Vol. 2, p. 614. 


Sandstone, massive, 

Sandstone, flaggy. 

Sandstone, massive, gr'iyish. white. 

Sandstone, flaggy 

Shales, brown. 

Sandstone, grayish white. 

Shale, brown 


26 ' 








New River coal bed. 

Shales, brown. 


Shales, buff, sandy 

Sandstone, massive, pebbly, 

Shales, gray. 


Shales, sandy. 

Iron ore. 





Shales, sandy. 


feet 5 inches, 

4 feet inches. 
feet 4 inches. 
8 feet inches. 
feet 6 inches. 

5 feet inches. 

10 feet 

25 feet 



feet 6 inches, 







Mauch Chunk Red beds. 


Passing southwards through West Virginia the Potisville becomes 
much thicker. In southern Payette and northern Raleigh Counties 
the following members are present^®: 

Pottsville in Fayette and Raleigh Counties, West Virginia. 


Nuttall sandstone lentil to 200 

Sandy and argillaceous shale and sandstone (containing Harvey 

conglomerate lentil and Sewell coal near base), 600 to 625 

Raleigh sandstone — 75 to 150 

Berkley coal. 

Quinnimont shale, sandy ^ _- 180 to 200 

Quinniroont coal. 

Sandstone and shale (Thurmond) 460 to 550 

Total, exclusive of Nuttall lentil 1.306 to 1.525 

In southern Raleigh, northern Wyoming and Mercer Counties the 
section is as follows : 

Pottsville in Southern Raleigh. Northern Wyoming and Mercer County, 

West Virginia. 

Sandy and argillaceous shale and sandstone containing Harvey 

conglomerate and lentil and Guyandat sandstone lentil, 650 to 

Raleigh sandstone, coarse, 75 to 

Berkley coal. 

Quinnimont shale, - 200 to 

Quinnimont soal. 

Sandstone and shale (Thurmond, with Pocohontas No. 3 coal 

near middle), 600 to 




1,525 to 1,800 

South of the above locality, in southern Wyoming and Mercer 
Counties, West Virginia, in the Pocohontas region the Pottsville has 
the following development^*: 

70. United Stitei Ocolof^cal Bmrey, Polio 77, 1902. 

71. West Vlrfinla Oeoloflc«l Surrey Reportii, Vol. 2, 1902, p. 619. 


Pottsville in Southern Wyoming and Mercer Counties. West Virginia. 


Sandy and argillaceous shale and sandstone, 650 to 700 

Raleigh sandstone, coarse. _ 80 

Quinnimont shale, containing thin sandstone and a few coal seams 300 

Sandstone, heavy beds at top and bottom, with some shale and coal 

seams, — _ 380 

Pocohontas No. 3 coal. 

Gray and green argillaceous sandstone and sandy shale 360 


West of the above area in McDonald County, the general section of 
the Pottsville is as follows: 

Pottsville in McDonald County. West Virginia. 


Datson sandstone, coarse with sandy shale at base. 180 

Bearwallow conglomerate, coarse sandstone. 60 

Sandstone and shale with several important coal beds and Dismal con- 
glomerate lentil near center of formation in western area 490 

Haleigh sandstone, sometimes conglomerate, 100 

Sandstone and shale with many beds of workable coal. 700 

Coal, Pocohontas No. 3. 

Sandstone and shale, with the beds of coal, 360 

Mauch Chunk red shales. 

Further to the southwest, in the Cumberland Gap coal field of south- 
eastern Kentucky, the Pottsville group consists of the following 

Pottsville in Cumberland Gap Coal Field. 

Bryson formation containing one or two coal beds of workable thick- 
ness, — 200 

Hygnite formation, largely sandstone, coal beds at top and bottom,.., 460 

Catron formation, largely sandstone, contains several coal beds, 300 

Mingo formation, largely sandstone with several coal beds. 
Havre formation, mainly shale, although it also contains some sand- 
stone. - — 600 

Lee sandstone. — 1,200 


Still further to the southwest, in north central Alabama, in the 
Birmingham district, the Pottsville reaches its maximum develop- 
ment. In the Cahaba coal field, east of Birmingham, it is repre- 
sented by 5100 feet of strata, consisting largely of shales with in- 
terbedded coal seams and some sandstone. The sandstones predomi- 
nate in the lower portion of the formation, which comes to rest on 
the Parkwood shales of the Mississippian Period. A siliceous sand- 
stone member, 250 feet thick, forms the lower part of the group. It 
becomes conglomeratic at the base". Although the rocks are prob- 
ably for the most part of fresh water origin, yet the presence of 
marine fossils at certain horizons, from the bottom to the top of the 
formation, in the Warrior and Cahaba fields, shows that there were 
incursions of the sea at intervals during Pottsville time. 

72 United States Geolopicjil Surrey. Professional Paper 40, 1006. 
78! United BUtes Geological Swrey, Polio 175, 1010. 


Geologic History of the Pottsville Formation. 

Prom the present distribution of the Pottsville formation and the 
thickness^ composition, and relative age of its different members, 
some ideas may be obtained in regard to the conditions, under which 
it was deposted. Prom the description of the sections from various 
portions of the area over which the formation is distributed it is 
seen that it consists largely of coarse, clastic, or fragmental sedi- 
ments, such as sandstone and conglomerates, although in certain 
parts shales, with which coal seams are frequently associated, pre- 
dominate. As a rule the formation is characterized bv an absence 
of marine fossils. There are some exceptions, as in the case of the 
Mercer limestone and certain horizons of the Alabama Pottsville. 
The areas over which these occur and the vertical portions of the 
formation which they occupy are relatively speaking very small when 
compared with the total extent of the formation. Fossils of land 
plants, on the other hand, are comparatively abundant. Torrential 
cross bedding is common in many of the Pottsville sandstones and 
conglomerates. More or less lenticular shaped bodies of conglom- 
erate in sandstone, and lenses of sandstone in shale, and vice versa, 
are also of frequent occurrences. These characteristics, in addition 
to the presence of numerous coal beds in some areas, point to a 
continental origin for the Pottsville formation, that is that the for- 
mation was laid down on a low lying plain by streams flowing across 
it from adjoining more or less mountainous areas. These streams de- 
posited much of their load of sediment directly on the land in the 
form of large alluvial fans. The finer muds, however, were often 
washed out into large lakes and swamps which existed in the de- 
pressed portions, over the low lying plain on which the Pottsville 
was deposited. This plain was gradually subsiding throughout Potts- 
ville time, which accounts for the great thickness of the formation in 
places. Occasionally the subsidence was more rapid than the rate 
of deposition. Then the sea from the southwest invaded the area for 
a time, and the remains of marine organisms accumulated in the 
sediments deposited underneath its waters. Stratigraphically speak- 
ing, the lowest or oldest members of the Pottsville are found in the 
Southern Anthracite region of Pennsylvania and in the Pocohontas 
region of southern West Virginia. Attention has already been called 
to the fact that the Pottsville of the Southern Anthracite Field has 
been divided on the basis of paleobotanical evidence into four divis- 
ions, namely : the Lower Lykens, the Lower Intermediate, the Upper 
Lykens, and the Upper Intermediate divisions. The Lower Lykens 
contain coal seams 4, 5 and 6 and is about 500 feet thick, the Lower 
Intermediate is about 150 feet thick, the Upper Lykens contains coal 


seams 1, 2 and 3, and is about 300 feet thick, while the Upper Inter- 
mediate has a thickness of 250 feet. 

In southern West Virginia, and adjoining parts of Virginia, the 
roof shales of the Pocohontas coal, which form the lower part of the 
Clark formation of the Pottsville group of that section, contains a 
flora which corresponds to the No. 5 coal of the Lower Ljkens division 
of the Southern Anthracite Field thus showing that the lowermost 
beds of this section were deposited practically contemporaneously 
with the lower beds in the Southern Anthracite Field of Pennsyl- 

From the present distribution and nature of the outcrops it is 
apparent that toward the close of Pottsville time sedimentation was 
going on over an area extending from southern New York, southwest 
to central Alabama, over a strip of territory embracing the anthracite 
fields of Eastern Pennsylvania and extending nearly as far west as 
central Ohio. A large part of Pennsylvania, nearly half of Ohio, 
practically all of West Virginia, portions of western Maryland, east- 
em Kentucky and Tennessee, southwestern Virginia and northern 
Alabama and (Jeorgia were covered by Pottsville sediments. This 
area, which has been termed the Appalachian Basin, was at that time 
grdually subsiding, and sediments were accumulating over it at about 
the rate at which subsidence was going on. To the east of it was 
an old land mass which had been fui-nishing sediments to this area 
throughout much of Paleozoic time. Land also existed to the north 
and to the west. 

Deposition started in over this area, first in the Southern Anthra- 
cite Field of eastern Pennsylvania and in the Pocohontas region of 
southern West Virginia, also in northern Alabama. These are the 
areas over which the Pottsville has the greatest thickness, and were 
apparently the centers of greatest deposition. With the gradual sub- 
sidence of the Appalachian basin deposition spread out over a greater 
and greater area until the maximum was reached at the close of the 
Pottsville. In the case of eastern Ohio, the lowest member, the Sharon 
conglomerate, which contains the Sharon coal, corresponds in age to 
about the No. 2 and 3 coals of the Upper Lykens division according 
to David White. The Mercer coal corresponds to about the No. 1 
coal of the same division. In the Northern Anthracite Field of 
eastern Pennsylvania, at CampbelPs Ledge near Pittston, the dark 
plant bearing shales at the base of the Pottsville, which is only 56 
feet thick here, also correspond to the No. 1 coal of the Upper Lykens 
in age. 

Sedimentation in Pennsylvania during Pottsville time began in 
the Southern Anthracite Field and spread in a northerly and westerly 
direction. The Northern Anthracite Field was not reached until 


about the time No. 1 coal of the Upper Lykens division was being 
deposited in the southern field. The land mass to the southeast 
whici^ furnished these sediments must have been fairly rugged, as 
the Pottsville of eastern Pennsylvania consists largely of conglome- 
rates. In northwestern Pennsylvania sedimentation began with the 
Olean conglomerate, which is probably the equivalent of the Sharon 
conglomerate of Ohio, and therefore, was deposited at about the 
time of coals No. 2 and 3 of the Upper Lykens. Sedimentation com- 
menced in eastern Ohio and northern New York before it did in all 
portions of western Pennsylvania, because the Sharon and Olean con- 
glomerate are absent over much of this area, thus making the Conno- 
quenessing the lowest member. 

Attention has already been called to the fact that the Pottsville 
is made up principally of a continental type of sediments, marine 
fossils being entirely absent in most cases. It was deposited over 
the low lying plain formed by the gradually subsiding Appalachian 
basin by streams which originated on the elevated areas surrounding 
it, and which flowed across it to the sea which probably existed oflP 
in a southwesterly direction. These streams deposited much of 
their sediment in the form of huge alluvial fans on this plain. Dur- 
ing the greater part of the time deposition kept pace with the rate of 
subsidence, and the area remained above sea level. In the depres- 
sion on this plain large lakes and swamps formed in which the deposi- 
tion of the finer sediments, such as clays and shales occurred. Large 
deposits of peat accumulated in many of the swamps, which on later 
burial were converted into the Pottsville coals of today. Occasion- 
ally over portions of the area subsidence was a little more rapid than 
the rate at which deposition was going on, and the sea encroached on 
those parts of the plain thus submerged. At these times beds con- 
taining marine fossils were deposited. The two limestones of the 
Mercer horizon in western Pennsylvania are examples. The maxi- 
mum area of deposition was reached at the close of the Pottsville. 

After the deposition of the Pottsville,. sedimentation continued with 
occasional interruptions over a lai^e part of this area during the rest 
of Pennsylvanian time and on into the Permian. The Pottsville 
sediments thus became buried under a considerable load of overlying 
sediment which resulted in their consolidation and the conversion 
of the peat which had accumulated in its swamps into coal. At the 
close of the Permian most of the area under discussion, including 
eastern and central Pennsylvania, western Maryland, West Virginia, 
southwestern Virginia, eastern Kentucky and Tennessee, northwestern 
Georgia and northern Alabama, was involved in the orogenic disturb- 
ance which resulted in the folded structure of the Appalachian moun- 
tains. The strata of western Pennsylvania and eastern Ohio were 


elevated vertically above sea level by this movement underneath the 
earth's surface, but were not titlted from their original horizontal 
position to any great degree. Since the close of the Paleoawic, the 
whole region has been undergoing erosion. Over considerable por- 
tions of the original area of deposition the Pennsylvanian sediments 
have been entirely stripped, while in other cases erosion has pro- 
ceeded only down to the Pottsville, exposing it at the surface. Over 
the remaining areas the Pottsville is still buried underneath over- 
lying strata. 




Certain members of the Pottsville formation are at times sufficiently 
pure quartz sandstones to be available for glass making purposes. As 
a rule the Pottsville sandstones are aU sufficiently friable to be readily 
crushed to sand either in wet or dry grinding pans. Quartz sand- 
stones available for glass sand occur in the Pottsville of western 
Pennsylvania, eastern Ohio, and northern West Virginia, at numer- 
ous localities. No where, however, do they excel the Oriskany sand- 
stone in purity, and as a rule they rarely are equal to it in this re- 
si>ect, so that most of the glass sand obtained from the Pottsville is 
used for plate, window, and bottle glass, especially the latter two. 

In western Pennsylvania portion of the Homewood and Connoque- 
nessing members of the Pottsville formation are in certain areas suf- 
ficiently pure qtiartz sandstone to yield glass sands suitable for the 
manufacture of plate, window and bottle glass. As a general rule 
more clayey material and iron bearing minerals are present in even 
the purest Pottsville sandstones than in the Oriskany of central Penn- 
sylvania. Occasional flakes of muscovite mica are also of common 
occurrence. The clayey material is usually derived from decom- 
posed feldspar grains present in the rock. 

The following two* analyses show the composition of a selected 
pure quartz sandstone from the quarry of the Pittsburgh Plate Glass 
Company at Kennerdell, in southern Venango County, and the*com- 
position of an average sample of sand produced by crushing the sand- 
stone obtained in the quarry of the Fox Silica Sand Company at 
Doguscahonda, in central Elk county, respectively: 

Analyses of Glass Sands from Pottsville Formation. 


Fe*o«', iiiimnriiiiii ~ in..i..i"iii"iiii"iiiii 


OaO — - — _ 

H«0. - 

TIO« - ^ 

o a « 
<> > S a 




Both of the above samples are from the Connoquenessing member 
of the PottsviUe formation. The following screen analyses show the 
percentage of the various sized grains present in Pottsville sandstones 
from various localities in western Pennsylvania. 

Screen Analyses of Pottsville Glass Sands. 





Remaining in 10 mesh screen, 

Through 10 remaining on 14, — .. .. 

Throoffh 14 rftmalnInK on 90. —---———-- 



































Through 90 remaining on 88, 

Through 28 remaining on 86 

Through 85 remaining on 48, .. .. 

Through 48 remaining on 66, 

Through 65 remaining on 100 ^... 

Through 100 remaining on 150, . .. . ... 

Through 160 remaining on 200, 

Through 900, 













1. Cmshed, ecreened, and washed sand from quarry of Pittsburgh Plata Glasa Con^any at Ksn- 
nerdell, south Venango County. Connoquenneesing horlzo«i. 

S. Crushed dry, and screoied sand from quarry of Fox Slhca Sand Oo., Dogusoahonda, eeotral 
Elk County. Oonnoquennessing horizon. 

3. Crashed, screened, and washed sand from American Window Glass Co., at Derry Station, 
eastern Westmoreland County, Homewood horizon. 

4. Crashed, screened and washed sand from quarry of Dunbar Furnace Co., Dunbar, tn northern 
Fayette County, Homewood horizon. 

The Pottsville sandstones for the most part have only been par- 
tially cemented by siliceous bond, so that they can be crashed com- 
paratively readily into loose sand. Cementation has been consider- 
ably less than in the case of the unaltered Oriskany sandstones of 
central Pennsylvania. 

In the discussion on the geologic history of the Pottsville forma- 
tion it has been shown that most of its conglomerate and sandstone 
members were deposited as flood plain sediments and large alluvial 
fans by streams flowing from a more or less rugged land area, across 
a low lying, nearly level plain. In the case of some of the sand- 
stones the sorting action was sufficiently perfect to result in the 
deposition of nearly pure quartz sands. Undoubtedly the nature of 
the rocks exposed to weathering and erosion on the land area which 
contributed these sediments played an important part in determining 
the nature of the sandstones laid down. Where sandstones and quart- 
zites which already contained predominating amounts of quartz were 
the chief contributors, "the resulting sandstones were nearly pure. 

Sandstone beds deposited under these conditions are apt to show 
considerable variations both vertically and laterally. The coarsest 
material is deposited nearest the land area undergoing erosion, and 
along the stream channel nearest itself, while the fine muds and clays 
are deposited in lakes and swamps existing in the depressions be- 


tween streams. On such a nearly level plain the streams will also 
frequently shift their channels. They will also split up into numer- 
ous distributaries on the alluvial fans formed. As a result beds of 
conglomerate may be encountered in the sandstones deposited under 
such conditions as well as lenses of shale. The sandstone members 
will not necessarily remain uniform in thickness over an extensive 
area^ but will thicken and thin when followed laterally, and often 
will pinch out entirely, their places being taken by shales. 

Comparatively speaking, therefore, it is only rarely that suflSciently 
pure beds of Pottsville sandstone are found suitable for glass sand. 
Entombed plant remains, which have been converted into coal, are 
also present at times, and render portions of the sandstone undesir- 
able for glass making on account of the carbon content introduced. 

The position of the sandstone with respect to the surface topography 
is another important factor which determines whether or not it can 
be utilized. In preparing glass sand from the Pottsville there is 
only a small margin of profit and, therefore, the sandstone must 
occur in such a position that it can be quarried as cheaply as possible. 
The amount and direction of the dip of the beds, if any, and the 
amount of cover which has to be removed, are important factors in 
determining whether a certain occurrence of otherwise suitable sand- 
stone can be economically quarried or not. Transportation facili- 
ties and the distance to market are of course also factors of prime 

Preparation of the Sand for the Market. 

Two methods are used in western Pennsylvania to prepare glass 
sands from the Pottsville sandstone for the market. In one case the 
sandstone is put through a jaw crusher and chaser miU or wet grind- 
ing pan, and is then run through screw washers, in a manner exactly 
similar to that used in preparing glass sands from the Oriskany sand- 
stone of central Pennsylvania. Where the sand is of sufQcient purity 
to be suitable for plate glass, or similar grades of glass, it is also 
dried. Often, however, as in the case of sand for window and bottle 
glass this is not done, the sand being shipped wet. 

For the cheapest grades of glass sand washing is not resorted to. 
The sandstone is passed through a jaw crusher and then goes to a 
dry grinding pan, where it is crushed to loose sand. After it has 
been screened it is ready for the market. This method of preparing 
the sand, together with a description of the machinery employed, has 
already Jbeen taken up in a previous chapter under the head of Silica 
as a raw material in the manufacture of glass. 


Examination oi Undeveloped Areas. 

All of tbe sandstone of sufi9cient purity to attract attention as 
being possibly suitable for glass sand in the Pennsylvanian strata of 
western Pennsylvania are, according to the writer's observations, 
confined to tbe members of the Pottsville formation. Therefore, in 
looking for available deposits of this type of sandstone in western 
Pennsylvania particular attention should be paid to the outcrops of 
this formation. As has already been stated, however, the Pottsville 
does not every where contain beds of sandstone sufficiently pure for 
glass making purposes. 

When a bed of sandstone has been discovered, which as far as its 
appearance in the hand specimen is concerned looks favorable, chem- 
ical analyses of representative samples should be made, especial at- 
tention being paid to the iron content, as this is the most deleterious 
constituent that is apt to be present. A microscopic examination of 
the sand for mineral constituents, besides quartz, that may be present 
is also desirable, as is a furnace test of the sand where this is feasable. 

A careful determination of the extent of the sandstone should be 
made before any extensive plant is erected to crush it. On account 
of the conditions under which the Pottsville formation was deposited, 
sandstone beds in it are apt to vary considerably within a compara- 
tively short distance, both vertically and horizontally. A careful 
investigation should, therefore, be made to determine whether a large 
enough quantity of the pure sandstone is present to supply a plant 
for a sufficient length of time to warrant its erection. Some of 
the things that should be looked for in examining an area of Potts- 
ville sandstone as a possible site for a glass sand quarry are the pres- 
ence of conglomerate lenses in the sandstone, especially in the north- 
western part of the state, likewise the presence of shale lenses and 
changes in the clay and iron oxide contents of the sandstone, both 
vertically and laterally along a face of exposed sandstone. 

Occasionally thin seams of coal, distributed through the sandstone 
at particular horizons, may readily render portions of it unsuitable 
for glass sand. Variations like those indicated above may make 
large portons of a particular bed of sandstone undesirable for glass 
sand. The thickness of a particular sandstone member may also 
change rapidly. 

The situation of the bed of sandstone with respect to the surface 
topography is another factor of extreme importance. If the bed dips 
from the horizontal, the amount should be carefully noted. In this 
case the cover of overlying strata, as the sandstone is followQJ^wn 
on the dip from the outcrop, may soon become so great as to make 
further quarrying operations out of the question, and in as much as 
underground mining operations are as a rule too expensive a method 


for obtainisg glass sands of the grade available from the Pottsville 
formation, such an occurrence would not be desirable for a glass 
sand quarry. Where the sandstone bed is horizontal, the amount of 
overlying material should be carefully determined in the area over 
which future quarrying operations will probably extend. There may 
be so much cover present that stripping will be too expensive to war- 
rant the selection of that particular site for'a quarry. 

Transportation facilities and nearness to market are other factors 
of prime importance. When the sand is to "be washed, the question 
of available water supply should be looked into, especially during 
the latter part of the summer and early fall. During the fall of 1914, 
the writer came across several plants that were operating at a very 
considerably reduced rate of production on account 6t the lack of a 
sufficient supply of water for washing the sand. This usually means 
a very appreciable loss to the company. 

Distribution of the Workable Deposits In Pennsylvania. 

Outcrops of the Pottsville formation are found in the following 
counties of western Pennsylvania: Aimstrong, Beaver, Cambria, 
Clarion, Clearfield, Crawford, Elk, Fayette, Forest, Indiang, Jeffer- 
son, Lawrence, McKean, Mercer, Somerset, Venango, Warren and 
Westmoreland. Of these, as far as the writer has been able to learn, 
the following have sand quarries located within their boundaries at 
the present time that are producing some glass sand, or have had such 
quarries during the past: Clearfield, Elk, Fayette, Forest, Jefferson, 
McKeaVi, Venango, Warren and Westmoreland. These quarries are 
described in the next chapter. 





Clearfield County. 

In Clearfield County the Pottsville formation has a thickneBB of 
from 275 to 325 feet, and consists largely of cross bedded sandstones 
and shales. The upper bed is often conglomeratic in its nature 
and a coarse conglomerate is frequently found at its base^*. Outcrops 
of this formation that contain sandstone beds of sufficient purity to 
be utilized for glass sand occur in the northwestern part of the county 
at Falls Creek* 

In the northwestern portion of the town of Falls Creek, the Fit»- 
patrick Glass Company at one time operated a quarry for glass sand 
in the Pottsville sandstone. The sand was washed before being 
used. When this company ceased operations the quarry was aban- 
doned and the plant dismantled. It was located on a spur of the 
Buffalo, Jlochester and Pittsburgh railroad. The strata at this quarry 
lie almost horizontal, there being only a slight dip toward the south- 
east To the northwest, along the Buffalo, Rochester and Pittsburgh 
i«ailroad, in a cut, a shale with a thin seam of coal is exposed under- 
neath the sandstone. To the southeast the sandstone passes under- 
neath later strata. 

A sketch showing the plan and approximate size of the quhrry is 
given in Figure 1, Plate XCII. Considerable variation shows in 
the quality of the rock along the working face, as is shown in the 
diagram. The best grade occurs at the south end of the quarry. 
At this place there are one to two feet of soil overlying the sand- 
stone. Thirty-eight feet of the latter are exposed in the working 
face, of which the upper nineteen are rather coarse in texture, while 
the lower nineteen are made up of medium to fine sized grains. The 
rock is white in color and contains only small amounts of day^ 
material. Here and there a little discoloration by limonite may be 

Elk County. 

Outcrops of the Pottsville sandstone occur over large portions of 
Elk County, and in many localities they are so situated as to make 
conditions favorable for quarrying operations. The strata under- 
lying Elk County are almost horizontal and where sandstone mem- 
bers of the Pottsville cap the divides between the stream vall^s, 

74. Second Geological Surrey of PennByiraiiit, Final Siiznmanr Beport, Vol. 8, Part 1, 1M6» 
p. 1866. 


' ■>■ J ilOO -(/ 



as frequently happens, they are readily accessible for such operations. 
At St. Marys, in east central Elk County, the geologist of the Second 
Qeological Survey of Pennsylvania, measured the following section 
of Pottsville strata: 

Section of ttie Pottsville at St. Mary's.^* 

Feet. Inches. 

Johnson Run sandstone and shale (Homewood), 32 

Alton upper coal bed, 2 7 

Shale. 18 

Alton lower coal 3 

Kfnzua Greek sandstone (Oonnoquenessing) 45 

Shale and coal 10 

Olean conglomerate. 50 

IW 7 

During the summer of 1914, four companies were operating sand 
plants in Elk county, namely, the Fox Silica Sand and Stone Co., 
the Ridgeway Sand and Stone Co., the Ridgeway-Croyland Silica Sand 
Co., and the White Silica Sand Co. 

Fox Silica Sand and Stone Company. 

The plant of the Fox Silica Sand and Stone Company, is located at 
the station of Daguscahonda on the Pennsylvania railroad, about 
half way between Ridgeway and St. Marys. The quarry is situated 
on top of the hill, on the north side of Elk Creek Valley. It is about 
425 feet higher than the level of the railroad track at the plant. An 
old quarry of considerable size was at one time operated here for 
building stone. 

At present all the sandstone quarried is crushed into sand. The 
present working face runs nearly north and south, and is about 250 
feet long. At the southern end a lense of clay about 4 feet thick 
was encountered, which pinches out both in a northerly and southerly 
direction. At the north end of the quarry the following section 
was measured: 

8 feet soil with pieces of broken sandstone. 
3 feet shattered sandstone with some soil. 
14 feet white quartz sandstone. 

At the southern end of the quarry, where the clay lense referi*ed 
to above pinches out, a working face 30 feet high is being developed. 
The clay lense contains abundant plant remains, as does also some of 
the sandstone directly below it. Much of the sandstone is distinctly 

Figure 2, Plate XCII shows a view taken in this quarry near the 
northern end of the working face. 

The sandstone is blasted down and loaded into cars, which are 
hauled by a small steam locomotive about 800 feet along the hillside, 
to the head of a gravity incline. The cars are let down this incline 

« 7S. Second Oeoloflcal Snrrej of PenntTlT^nlt. Flntl Snmmtry B4>port, Vol. 8. Part I, p. 1881. 



to the mill. Dry crusliing is employed and the sand is simply 
screened without washing. Plate XCIl I shows the flow sheet of the 
plant. During the summer of 1914 an additional jaw crusher and 8 
loot di*y grinding pan were being installed* Each of these pans has 
a daily capacity of 150 tons. This brings the total possible output 
of the plant up to 300 tons per day. The gi*eater portion of the 
production is sold as glass sand, principaUy to window glass manu- 
facturers. Three grades of sand are produced, of which the first 
two are sold as glass sand, while the third or poorest, is sold for 
building purposes, etc. An analysis of an average sample of tlie 
best grade of sand produced showed the following compositions : 

Analysis of Glass Sand, Fox Silica and Stone Company. 

SiO, 96.08 

AUOa, — 2.35 

Fe,Oa 37 

MgO .08 

CaO - 18 

HtO 67 

TIO.. 15 


A screen analysis gave the following results: 


Passed through 10 mesh, remained on 14 mesh, .046 inches, 04 

Passed through 14 mesh, remained on 20 mesh, .0328 inches, 08 

Passed through 20 mesh, remained on 28 mesh, .0232 inches, . . .91 

Passed through 28 mesh, remained on 35 mesh, .0164 inches, 6.86 

Passed through 35 mesh, remained on 48 mesh, .0116 inches, 30.33 

Passed through 48 mesh, remained on 65 mesh, .0082 inches 30.85 

Passed through 65 mesh, remained on 100 mesh, .0058 incljes, 17.85 

Passed through 100 mesh, remained on 150 mesh. .0041 inches, 3.97 

Passed through 150 mesh, remained on 200 mesh, .0029 inches, 2.12 

Passed through 200 mesh, 5.00 


Ridgway Sand and Stone Company, A. A. Urmann, Proprietor. 

The plant of the Ridgeway Sand and Stone Company is situateil 
about one and one-third miles east of Ridgway, on top of the hill on 
the north side of Elk Cre^ Valley. It is connected with the Penn- 
sylvania railroad by a long spur, which leaves the line between Ridg- 
way and St. Mary's about three miles above Ridgway. 

A practically horizontal bed of Pottsville sandstone caps the hill at 
this place. This was at one time very extensively quarried for cut 
stone for masonry construction work and other building purposes. 

At present all the stone taken out is crushed into sand. Many 
loose boulders of Pottsville sandstone are scattered over the surface 
in the vicinity. These are being largely utilized for the same pur- 
pose. During the summer of 1914 rock was being quarried from the 
solid face at only one place. Here a face about 200 feet long and 
38 feet high with 3 feet of solid cover, had been opened up. Figure 
1, Plate XCIV shows its appearance. Only selected portions of 



















Fig. 2. Viflw in ijunrry of Ridgway-Croylnnd Silien Snnd Cumiiniiy, Gar 


the sandstone can be used for glass sand. A large percentage of the 
rock contains far too high an iron content to be suitable for glass 
making. As a rule the surface boulders run lowest in iron. The 
size of the grain varies considerably from place to place, both verti- 
cally and horizontally, but no conglomerate was noticed. 

Two plants for crushing the sandstone, also located on top of the 
hill, about 500 feet above the level of Elk creek, are operated at this 
property. Each is equipped with a jaw crusher and an 8 foot Steven- 
son dry grinding pan. The sand is screened but not washed. Steam 
power is employed. Each mill has a daily output of 100 tons of 
sand. The company owns two small steam locomotives to haul the 
sand from these plant over a 3 mile siding to the Pennsylvania rail- 
road along Elk creek. The siding and engine were part of the prop- 
erty of the company which formerly operated a building stone quarry 
at this site. 

The output at present is largely sand and crushed stone for con- 
crete, furnace sand, molding sand, grinding and polishing sand for 
plate glass manufacture, and a little second class glass sand. 

Rldgway-Groyland Silica Sand Company, A. A. Urmann, Proprietor. 

The plant of the Ridgway-Croyland Silica Sand Company, is lo- 
cated at Garovi station about one mile south of Croyland, on the Bidg- 
way branch of the Pennsylvania railroad running to DuBois. The 
plant is situated along the railroad, while the quarry is up on the 
hill on the east side of the valley, at ^n elevation of 470 feet above 
the level of the track. The strata are practically horizontal at the 
quarry. A face of sandstone about 240 feet long, bearing N 17° E, 
has been opened up. The following section was measured near the 
middle of it: 

Section at Quarry of Ridgway-Croyland Silica Sand Gompany. 

3 feet soil. 

10 feet conglomerate. 

6 to 8 feet clay (a lenticular bed, pinches out at north end of 

6i feet fine grain sandstone. 

IJ feet shale (lenticular. Pinches out at both ends of the quarry.) 

29 feet nearly white sandstone with occasional thin seams contain- 
ing pebbles. These however make up only very small parts of the 
bed.) . Figure 2 Plate XCIV shows a view taken in this auarry. The 
sandstone is blasted down, loaded into cars and hauled a short dis- 
tance by mules to the head of a gravity incline, which leads to the 
plant at the railroad. A jaw crusher and dry grinding pan are em- 


ployed for crushing the sandstone into sand, which is then screened 
but not washed. The plant has a daily capacity of 100 tons of sand, 
very little of this sand, however, is sold for glass making. The con- 
glomerate encountered in the quarry is crushed and sold for concrete 

White Silica Sand Company. 

The plant of the White Silica Sand Company is situated about four 
miles east of St. Marys, on the Pittsburgh, Shawmut and Northern 
railroad, along the northwest side of the track. Pottsville sand- 
stone, lying nearly horizontal, forms the upper stratum on the north- 
west side of the hill. There are a considerable number of loose 
boulders scattered over the surface, although the sandstone itself is 
covered by 4 to 5 feet of soil. These surface boulders are gathered 
and sent to the mill to be crushed into sand. The difficulty with this 
method of obtaining sandstone is that a large amount of track has to 
be laid to get any great tonage of rock. Therefore, a site was being 
stripped during the fall of 1914 that a quarry could be opened in the 
bed rock itself. This is up on the hill, about three-fifths of a mile 
from the plant at the railroad. The sandstone is loaded into cars 
and hauled to the mill by mules. 

Near the above site a small opening, about 50 feet square, was 
made during previous operations, but was later abandoned. The 
following was measured here: 

Section, White Siflca Sand Company Quarry. 


Soil. 4 

Coarse quartz sandstone containing some moscovite mica, S 

Sandstone containing abundant carbonized plant remains, 8 

Coarse white sandstone, 3| 

Fine grained sandstone, 8 

Below this a sandstone with abundant plant remains was partially 

On the whole the sandstone at this locality is not very favorably 
situated for conducting quarrying operations. The surface is nearly 
level for a considerable distance and difficulty will, therefore, be ex- 
perienced in draining any quarry which is opened. 

Considerable exploratory work is necessary to determine the nature 
of the sandstone underlying the area, as there are practically no out- 
crops of bed rock. 

A small crushing plant has been erected. The sandstone is passed 
through a jaw crusher and then goes through a No. 18 Pulverizer, 
manufactured by the American Pulverizer Company of St. Louis. 
This has already been described in a previous chapter. After screen- 
ing the sand is ready for the market The machinery is run by a 
gasoline engine. The plant has a maximum output of about 50 tons 

FLATii XV\. 
X quarry of Dunbar Kiirnneu Cuin|)ony, Dunbar, Pa. 


per day of ten hours. Very little sand has been sold for glass mak- 
ing purposes, most of it being used for concrete in building construc- 

Payette Ctounty. 

The PottsviUe formation crops out at the surface along the flanks 
of two broad anticlines running in northeast and southwest direc- 
tion across the eastern half of Payette County. In this region it has 
a thickness of from 150 to 180 feet and consists of three members, 
namely, the Homewood, the Mercer and the Connoquenessing^'. 

The highest, or Homewood member, is usually a massive quartz 
sandstone, varying in thickness from 30 to 80 feet. It is at times 
conglomeratic, but the pebbles are not abundant enough to be con- 
spicuous. The Mercer shale member varies in thickness from 20 to 
50 feet. At times it contains irregular beds of sandstone, and gen- 
erally a thin streak of coal is present. The Connoquenessing does 
not exceed 100 feet in thickness, and is usually less than this, being 
exceedingly irregular in this respect. As a rule it is coarse, irregu- 
larly bedded sandstone, that frequently contains lenses of shale. In 
places a coarse conglomerate is also present. Of these three mem- 
bers, portions of the Homewood consist at times of sufficiently pure 
quartz sandstone to yield glass sand. Buch sandstone has been 
quarried at a number of places in Fayette County. During 1914, 
two companies, the Dunbar Furnace Company, and the Yough Sand 
and Stone Company operated sand ^plants in this county. 

Dunbar Furnace Company. 

The sand plant of the Dunbar Furnace Company is situated above 
Dunbar creek, on a small tributary which enters that stream from 
the south, about three-fourths of a mile above the town of Dunbar. 
The quarry is located on the hill, east of the plant, in the Homewood 
sandstone member of the PottsviUe, which at this place has a dip of 
16® to the northwest. Figure 1, Plate XCV shows a plan of the 
quarry and Figure 2 is a view taken in the quarry to show the ap- 
pearance of the present working face. This is about 540 feet long 
and 60 to 65 feet high. The cover of soil, which has to be stripped, 
nowhere exceeds 2i feet. It is loaded into carts and hauled to one 
side. Some of the loose boulders of sandstone present in it are 
utilized for sand. The transition between the soil and the bed rock 
underneath is a sharp one. 

Practically all of the present working face consists of massive white 
quartz sandstone. Much of it crumbles readily to sand when rubbed 
in the hand, especially after it has been exposed to the atmosphere 
for some time. Near the bottom of the working face thin streaks 
of coal are present locally, and the sandstone often contains abundant 

76. United States Oeoloi^cal Surrej. Folios 83 and 94. 


car.bouized plant remains, rendering it undersirable for glass sand. 
Uei'e and there thin lenses of very coarse, almost conglomerate sand- 
stone occur, but they are not present in sufficient quantity to be very 
detrimental. Some limonite stain occurs along the joint planes in 
places, and at times irregularly distributed through the sandstone, 
so that portions of the working face are rendered valueless for glass 
sand on this account. This, however, is not very wide spread. A 
platy sandstone of reddish color occurs at the north end of the quarry, 
being present as a thin capping at the north end of the present work- 
ing face. 

The sand is blasted down and loaded into" cars which are hauled 
by mules to the head of a gravity incline, down which the cars are 
sent to the mill. This incline is about 1800 feet long and about 245 
feet higher at the top than the level of the creek on which the plant is 
located. The sandstone is passed through a jaw crusher and wet 
grinding pan. It is then screened and passed through screw washers. 
None of it is dried at present, although, the plant is equipped with a 
Cummer dryer for this purpose. It is stored in stock piles outside 
of the mill building. The plant is equipped with three wet grinding 

At the time of the writer's visit during the fall of 1914 it was not 
in operation on account of a lack of sufficient supply of water to run 
the washers. 

Glass sand and railroad sand^ are prepared at this plant. The 
former is used for making skylights, wire plate glass, window and 
other similar grades of glass. An analysis of an average sample of 
the best grade of glass sand produced showed .12% FegOg. This sand 
had a gray color with a light shade of brown. Here and there a 
grain of sand had a thin film of limonite adhering to it. Occasional 
specks of muscovite were also visible. A screen analysis gave the 
following results: 

Screen Analysis of Glass Sand, Dunbar Furnace Company. 


Passed through 10 mesh, remained on 14 mesh, .046 Inches, 44 

Passed through 14 mesh, remained on 20 mesh, .0328 Inches, .30 

Passed through 20 mesh, remained on 28 mesh, .0232 Inches, — 59 

Passed through 28 mesh, remained on 35 mesh, .01©4 Inches — 2.08 

Passed through 35 mesh, remained on 48 mesh, .0116 Inches 8.27 

Passed through 48 mesh, remained on 65 mesh, .0082 inches 13.31 

Passed through 65 mesh, remained on 100 mesh, .0058 Inches 44.49 

Passed through 100 mesh, remained on 150 mesh, .0011 inches, 22.55 

Passed through 150 mesh, remained on 200 mesh, .0029 inches, 5.95 

Passed through 200 mesh, _ 1.35 

Tough Sand and Stone Company. 

The plant of the Yough Sand and Stone Company is located on a 
siding of the Western Maryland railroad, on the west side of the 
Youghiogheny Eiver, a short distance above the point where a small 


creek enters the former south of South Connellsville. The quarry is 
situated on a side of a hill about 135 feet above the mill, and is con- 
nected with the latter by a short gravity tram. The quarry was just 
being opened at the time of the writer's visit during the faU of 1914. 
At that time most of the rock crushed was taken from large talus 
boulders along the outcrop. The rock itself, however, was also well 
exposed. The Homewood member of the Pottsville is being opened 
up. While some of it is a white quartz sandstone, there are consid- 
erable portions that are colored a light yellowish brown by limonite. 
Inasmuch as the quarry is located on the hiUside, and the rock dips 
into the hill, it will not be possible to quarry the rock any great dis- 
tance back from the outcrop. 

The plant is equipped with a No. 4 Blake jaw crusher and an 8 foot 
grinding pan, with double discharge. This mill has a daily capacity 
of about 200 tons. There are two batteries of three screw washers 
each, for washing the sand. This is shipped wet. The machinery 
is run by electric power. Water for washing the sand is pumped 
from the Youghiogheny River. During 1914 only one grade of sand 
was produced. This was sold largely as railroad sand, moulding 
sand, plasterer's sand, and building sand. One win'dow glass factoi^ 
was supplied with glass sand. 

The Homewood sandstone has also been quarried for glass sand at 
other localities in Fayette County than the two above mentioned. A 
crushing plant was formerly in operation in South Connellsville, on 
the opposite side of the river from the present plant of the Yough 
Sand and Stone Company. Another abandoned quarry is located 
on the opposite side of Dunbar Creek from the plant of the Dunbar 
Furnace Company. A plan^ was also operated at one time on the 
east side of the Youghiogheny river about a mile above Layton. 

Forest County. 

Outcrops of the Pottsville occur over a large portion of Forest 
County. Sandstone members of this formation often cap the divide 
between the streams. When sand beds are of sufficient purity to be 
utilized for glass sand they make ideal sites for quarries. During 
1914 there were no sand plants in operation in Forest County, but one 
company, the Spring Creek Glass Sand Company, was erecting a large 
up to date plant, and opening a quarry at Straits, in the southeastern 
part of the county, on Spring creek. This place can best be reached 
from Sheffield, over the narrow gauge Tionesta Valley railroad. 
The sand, however, will be shipped over a standard gauge track down 
Spring creek valley, which connects with the Pittsburgh, Shawmut 
and Northern railroad at Hallton. 


. Spring Greek Glass Sand Company. 

The plant of the Spring Creek Glass Company is located on the east 
side of Spring creek valley, near the bottom of the valley, while the 
quarry is being opened upon the top of the hill above it. A sandstone 
member of the Pottsville forms the top stratum of the hills in this 
vicinity. In the case of the Spring Creek Glass Sand Company's 
property the bottom of the sandstone member in which the quarry is 
being opened is about 260 feet above the railroad track at the mill. 
Beyond the quarry site the hill rises very gradually for another 130 
feet in elevation. The quarry and mill are connected by a gravity 
incline. Figure 1, Plate XCVI shows the appearance of the valley 
at the property of this company and Figure 2 shows a nearer view 
of the plant itself. 

The sandstone and conglomerate member of the Pottsville forma- 
tion, which caps the rather steep cliff forming the sides of the Spring 
Creek Valley in the vicinity of Straits, has, at the side of the Spring 
Creek Glass Sand Company's quarry, a thickness of 30i feet. It 
lies practically horizontal. At the time of the writer's visit, dur- 
ing the fall of 1914, quarrying operations were just beginning. The 
upper 14^ feet of sandstone has been partially opened up along a face 
about 10 feet wide, and 4 to 5 feet deep. The rock exposure was a 
very pure white quartz sandstone. Only occasionally was a little 
limonite noticed along joint planes. No conglomerate was present 
at this point. The lower half of the formation had not been broken 
into, except in a large boulder which had become detached from the 
cliff. In this boulder it proved to be badly stained by iron oxide. 
No conglomerate was noticed in the sandstone at the site selected for 
the quarry, but only a short distance to the south, along the cliff, 
layers of conglomerate make up a large percentage of the formation. 
In places over half the total thickness consists of conglomerate. 
These conglomerate beds in the sandstone are very irregular. UsuaUy 
they are not continuous, but lenticular in shape. Sometimes along 
the face of the cliff thin layers of conglomerate, one to two inches in 
thickness, are interbedded with the sandstone in such a manner as to 
practically render the entire thickness of the formation valueless for 
glass sand. North from the quarry site there is not very much con- 
glomerate, in the sandstone. Occasionally, however, pebbles up to 
one-fourth inch in diameter make up a prominent part of the forma- 
tion. The site selected for the quarry is freest from such pebbles. 
East of the quarry the gradually upward sloping surface is dotted 
with numerous loose boulders of white, nearly pure white quartz sand- 
stone, of excellent grade for glass sand. Usually only one foot or 
less of soil covers the sandstone. Excessive amounts of conglomerate 
and a rather high iron content in the lower portion of the sandstone 

1'1,ATK XC'Vl. 

I ax aO'THakc Jow Crusher 

-. T-i — 

3' lvyA/i:»to\A/n Cho:jcr Mill. 


O U 

— • I 

IC finc^h Revolvmq >3cr^en 

I 7 I 

U Q 

'^^'Scrcw Wa5he 




Inclined B^lfConv^^or 
Hon/onlal uult Conv^yjor 
Drainina f^oor. 


v3 hoi/t Ih'd ay Hand 
Hon/ on to I btlt Convesior. 
Inclined and Hor i^onful ncit Convey/or oyer Dryer 

Off am Hrytr 
Hcrucfi/ol Belt Conveyor^ 
Que kvt LlevQtor 
Rvvolvim^ df f( en 

6 If 

SforooG- J9/n^^ 

PLATi: XC/il 
Flow sheet of plant of Sprint; Oeek (Ilnss Stnul Company, Straiglits, Pa. 


member in which the quarry is located, may cause some difficulty as 
quarrying operations proceed. 

A modem sand plant has been erected at Straits by the Spring 
Greek Glass Sand Company. In it the sandstone is first passed 
through a 12x20 inch jaw crusher and then goes to a 9 foot Lewistown 
chaser mill, in which it is crushed to sand. Screw washers are em- 
ployed for washing, and a steam dryer for drying the sand. It is ex- 
pected that the plant will have an output of about 150 tons of washed 
and dried sand per day. The machinery is operated by a gas en- 
gine. A boiler has also been installed to supply the steam dryer. 
Plate XCVII shows the flow sheet of this miU. 

Jefferson Ck>uiity. ^ 

Prominent outcrops of Pottsville sandstone occur in eastern Jef- 
ferson county, north of Falls Creek, along the line of the Buffalo, 
Rochester, and Pittsburgh railroad and the Ridgway Branch of the 
Pennsylvania railroad. During the summer of 1914 four sand com- 
panies, namely: — the Palls Creek Sand and Stone Company, the 
Gocella Stone and Sand Company, .the Jefferson and Clearfield Stone 
and Sand Company, and the Silica Stone and Sand Company, were 
operating plants in this region. These companies are using sand- 
stone from the same horizon as that which is exposed in the aban- 
doned quarry at the Fitzpatrick Glass Company, at Falls Creek, in 
Clearfield county. 

Falls Creek Stone and Sand Company. 

The plant of the Falls Creek Stone and Sand Company is located 
about one and three-fifths miles north of Falls Creek, on a siding of 
the Buffalo, Rochester, and Pittsburgh railroad. The quarry is lo- 
cated on top of the hill at an elevation of about 125 feet above the 
level of the railroad at the mill. It is connected with the latter by 
a gravity incline about 1000 feet long. A working face 480 feet long 
had been opened up in a sandstone member of the Pottsville at the 
time of the writer's visit in 1914. The following section was ex- 


Section at Quarry of Falls Creek Stene and Sand Company. 

Soil 1 

Broken rock with some soil (used for crushed stone for concrete), 3 

Mnssive sandstone (upper 38 feet of medium grained texture; lower 12 

feet coarse grained texture), — - - 50 

A considerable percentage of white quartz sandstone suitable for 
glass sand was exposed in the quarry face, but reddish streaks dis- 
colored by iron oxide are distributed irregularly through much of it. 
and other portions are stained brown by limonite, thus spoiling it for 
glass sand. Careful sorting would, therefore, be necessary in order 


to use very much of the output of the quarry for glass sand. At 
present none of the output of the quarry is used for this purpose, al- 
though one or two trial ears of glass sand have been shipped which 
gave satisfaction. 

The plant is equipped with a jaw crusher, a 9 foot Stevenson grind- 
ing pan, screens, bucket elevators, a boiler and an engine. A long 
steam pipe runs from the boiler at the plant to the quarry to supply 
steam to the machine drill. On account of excessive condensation 
of the steam this arrangement has not proven very satisfactory. 

Qocella Stone and Sand Oompany. 

ThCsplant of the Gocella Stone and Sand Company is situated 
about 2,000 feet west of Harvey's Run Station, on a long spur of the 
Buffalo, Rochester, and Pittsburgh Railroad. Only a small quarry 
has been opened up, with a working face about 35 feet long. In it 
the following section was measured : 

Section at Quarry of Gocella Stone and Sand Oompany. 


Soil, 3 

Medium grained sandstone, — — 5 

' Very coarse grained sandstone 10 

^ Fine grained sandstone - 7 

A large amount of loose talus material occurs at this site, which 
has been drawn largely upon to supply the mill with sandstone. No 
glass sand has been produced, however, the output having been sold 
largely for furnace sand, engine and motor sand and building sand. . 

The plant is equipped with a No. 5 jaw crusher, and a 9 foot Steven- 
son dry grinding pan, together with the necessary bucket elevators, 
screens, etc. 

During the writer's visit in September, 1914, the mill was not in 

Jefferson and Clearfield Stone and Sand Company. 

The plant of the Jefferson and Clearfield Stone and Sand Company 
is located about one and one-fourth miles north of Falls Creek, on a 
siding of the Ridgway Branch of the Pennsylvania railroad. ' The 
quarry of the company is located at the top of the hill above the plant. 
It is about 135 feet above the level of the track at the mill and is 
connected with the later by a gravity incline. A quarry face about 
200 feet long running nearly north and south, has been opened up. 
The following section is exposed: 

Section at Quarry ol the Jefferson and Clearfield Stone and Sand Company. 


Broken stone with some soil (used for crushed stone for concrete 8 

Massive sandstone _ 45 


At the south end of the quarry the lower two-thirds of the sand- 
stone consists of nearly white quartz sandstone, while the upper one- 
third has a reddish tinge, due to the presence of iron oxides. At the 
north end the lower and upper one-third are white in color, while the 
middle one-third is reddish and contains some very coarse grained, 
almost conglomerate rock. This coarse rock pinches out toward the 
south end. Otherwise the rock is fairly uniform in texture. Some 
glass sand is produced. During 1914 two or three plants were being 
supplied. It was used for window and ribbed plate glass. 

An analysis of an average sample of this sand gave .14% Fe^O^. 
A screen test showed the following sized grains to be present: 

Screen Analysis. 

Per Ot. 

Passed through a 10 mesh, remained on 14 mesh, .046 Inches, .28 

Passed through a 14 mesh, remained on 20 mesh. .0328 Inches. 2.11 

Passed^ through a 20 mesh, remained on 28 mesh, .0232 inches. ... 8.75 

Passed through a 28 mesh, remained on 35 mesh, .0164 Inches 16.56 

Passed through a 35 mesh, remained on 48 mesh, .0116 inches 31.06 

Passed through a 48 mesh, remained on 65 mesh, .0082 Inches, 18.58 

Passed through a 65 mesh, remained on 100 mesh, .0058 inches 11.75 

Passed through a 100 mesh, remained on 150 mesh, .0041 Inches, 3.53 

Passed through a 150 mesh, remained on 200 mesh, .0029 inches. 2.13 

Passed through a 200 mesh 8.74 

In the quarry the stone is loaded into carts which are hauled to 
the head of the incline by mules. Here the stone is dumped into cars 
which take it down to the mill. 

It is the intention of the present operators to open another quarry 
along the cliff a short distance north of the present one, so that when 
blasting is going on in one quarry the men can be loading rock in the 

The plant is equipped with a jaw crusher and a 9 foot Stevenson 
dry grinding pan for crushing the sand. The capacity i& about 150 
tons daily. The glass sand is passed over an 8 mesh, shaking screen. 
It is not washed. 

Silica Stone and Sand Company. 

The plant of the Silica Stone and Sand Company is situated about 
three-fourths of a mile north of Harvey's Run station, on a siding of 
the Ridgway branch of the Pennsylvania railroad. Thus far only 
talus boulders of Pottsville sandstone have been crushed into sand. 
No quarry has been ^opened. There are no prominent outcrops at 
this place, the sandstone being every where covered by a considerable 
thickness of soil. This will make the opening of a quarry a rather 
expensive proi)osition. No glass sand has been produced by this 

The plant is equipped with a jaw crusher and a 9 foot Stevenson 
dry grinding pan, together with the necessary screens and bucket 
elevators, also an engine and boiler to oi)erate the machinery. 


McKean County. 

The Sergeant Glass Company at one time obtained some glass 
sand from talus boulders of Pottsville sandstone occurring on the 
hill above its plant at Sergeant station, along the Pennsylvania rail- 
road, southeast of Kane, in southwestern McEean county. The sand- 
stone was passed through a jaw crusher, chaser mill, and one screw 


washer. No quarry was opened, as the outcrops of Pottsville in this 
vicinity are covered by a mantle of soil of considerable thickness. 
No sand is produced at this locality at present. 

Yenanffo County. 

In southern Venango county the Pottsville formation has a thick- 
ness of from 120 to 130 feet^^. It can be divided into three members, 
namely: The Connoquenessing, the Mercer and the Homewood sand- 
8tone. The Connoquenessing is a thick bedded, resistant, saccharoid^ 
sandstone, which ranges in color from buff to white, and is non fos- 
siliferous. Some layers are not well consolidated and appear much 
like granulated sugar. On the whole, the rock is very clean and 
free from everything but silica, so that it often can be used for glass 
sand. The beds as a rule are more or less lenticular. In thickness 
this member of the Pottsville ranges from 30 to 50 feet. In southern 
Venango county the Mercer member is represented by only 6 inches 
to 2 feet of coaly shale. The Homewood, or topmost member of the 
Pottsville, is a coarse grained, massive sandstone, averaging about 
40 feet in thickness. It is generally a clean, white, finely cross 
bedded and loosely cemented sandstone. . 

During the summer of 1914, the Pittsburgh Plate Glass Company 
and the Venango Sand and Stone Company were operating sand plants 
in the vicinity of Kennerdell in southern Venango county. 

Pittsburgh Plate Glass Oompany. 

The sand plant of the Pittsburgh Plate Qlass Company is located 
on the east side of the Allegheny River a short distance below Ken- 
nerdell, on a siding of the Pennsylvania railroad. The quarry is 
on the west side of the river and back some distance from it, on top 
of the upland into which the river has cuts its valley. It is connected 
with the plant by an aereal tramway, made by the Trenton Iron 
Company, now the American Wire Rope Company, which is little 
over a mile in length. This tramway has 44 buckets, of about 900 
pounds capacity each, on it. In practice about 1200 buckets are 
run over it per fwenty hours. In as much as the quarry is only 
operated 10 hours each day, storage bins have been built at the load- 
ing station, so that the tramway can be run for 20 hours, which is 

77. United States Geolojrlcal Snrrex Polio 178. 


FJK. !■ DinRrum of qunrry of rittHbiirsli Pinto (iIush Cnm|ian3-. Kpiinrrdi'II . Pa. 

Fig. 2. View in muin imrtiuii uf tlio above quarry. 

I'LATE Xt'lX. 


























^ r 

» • 










necessary to supply the crushing plant with sufficient sandstone. 
Some auxiliary power besides gravity is necessary to operate the 

The floor of the quarry is about 400 feet above the level of the Al- 
legheny river. Figure 1, Plate XCVIII is a diagram of the quarry 
whUe Figure 2, Plate XCVIII and Figure 1, Plate XCIX are two 
views taken in the quarry. Figure 2, Plate XCVIII showing a por- 
tion of the main quarry looking west and Figure 1, Plate XCIX show- 
ing the working face at the southeast end. At the southeast work- 
ing face there are from 35 to 40 feet of practically horizontal Potts- 
ville sandstone exposed, with 1 to 2 feet of soil. Most of the rock 
exposed in this face is a white quartz sandstone. Oecaai0iially there 
is a little limonite stain along the joint cracks. An analysis of a 
selected specimen of the purer rock gave the following results: 

' Analysis of Pottsvllle Sandstone. Pittsburgh Plate Glass Company. 


810, 98.85 

A1,0. 1.14 

FeiOa - 06 

MgO — Trace. 

OaO 11 

H.O 21 

TiO, 14 


At the southwest end of the quarry 30 feet of sandstone are ex- 
posedy with about 4 feet of soil resting on top of it. Below this 
is a lower bench which is being taken out in order to make the entire 
floor of the quarry uniform in elevation. One foot of very car- 
bonaceous shale and six feet of light colored shale are exposed in 
this bench. This shale bed, however, is lenticular in shape, as it 
does not appear every where in the quarry at this horizon. Along 
some parts of the working face the rock is badly discolored -by iron 
oxides and cannot be utilized for glass sand. This is particularly 
true of a portion between the southeast face and the main quarry as 
shown in the diagram. About 60 per cent of the total output of 
sandstone at this quarry is utilized for glass sand in the manufacture 
of plate glass. The rest is used chiefly for grinding and polishing 

The rock is blasted down and loaded into cars, which are hauled 
by mules to bins at the loading station of the aerial tramway. The 
intention, however, is to eventually arrange the tracks in the quarry 
in such a manner that one will run parallel to the working face, so 
that cars can be run along it, by means of a small steam locomotive. 
Air drills are used in putting down vertical holes from the top. The 
rock is usually quarried in two benches. The air compressor is 
run by a gas engina 


The crushing plant of the Pittsburgh Plate Glass Company dur- 
ing 1914 was equipped with two 9 foot chaser mills, as shown in 
the flow sheet giyen in Plate C, another unit, consisting of a Jaw 
crusher, a 9 foot chaser mill, and six screw wafers was being in- 
stalled during the fall of 1914. This gives the plant a total capacity 
of 450 tons of sand per day. The sand is not dried at the plant, 
but is shipped wet to be dried later at the glass house. The ma- 
chinery is housed in a steel frame building, with brick walls, con- 
crete floors, and a sheet iron roof. The plant is equipped with «i- 
gines and boilers to operate the machinery. Figure 2, Plate XCIX 
shows its external appearance. Water for washing the sand is 
pumped frem the Allegheny river. 

An analysis of a sample of the washed and dried glass sand pre- 
pared at this plant gave the following results: 

Analysis of Qlass Sand from Pottsvllle Formation, Pittsburgh Plate Glass 

Company Plant. 

SIO, - 98.71 

AliO. 35 

FetO. 11 

MgO - None. 

OaO 24 

H,0 - 16 

TiO, 05 


A screen test of this sand gave the following results: 

Passed through 10 mesh, remained on 14 mesh, .046 inches, .42 

Passed through 14 mesh, remained on 20 mesh, .0328 inches. .78 

Passed through 20 mesh, remained on 28 mesh, .0232 inches ^ 2.18 

Passed through 28 mesh, remained on 35 mesh, .0164 inches, 7.28 

Passed through 35 mesh, remained on 48 mesh, .0116 Inchps 20.75 

Passed through 48 mesh, remained on 65 mesh, .0082 Inc<r • *'- 37.06 

Passed through 65 mesh, remained on 100 mesh, .0058 inch . 19.93 

Passed through 100 mesh, remained on 150 mesh. .0041 inches, - .85 

Passed through 150 mesh, remained on 200 mesh, .0029 inches, .10 

Passed through 200 mesh 03 


Venango Sand and Stone Company. 

This company is the successor of the Eennerdell Silica Sand Com- 
pany, which in turn succeeded the Kennerdell Sand and Manufactur- 
ing Company. The plant of this company is located on a siding of 
the Pennsylvania railroad about one and three-fourths miles above 
the town of Kennerdell. The Pottsville sandstone is exposed at 
the top of a steep cliff rising about 440 feet above the level of the 
river. A quarry face about 150 feet long has been opened up, which 
exposed the following section: 

Section at Quarry of Venango S»nd and Stone Company. 


Nearly white quartz sandstone, .i^ - 15 

Sandstone, with reddish color due to iron oxide. - — 3D 

Shale, with carbonaceous streaks near middle — 5 

Nearly white quartz sandstone, upper few feet slightly reddish In color, 55 


At present a new working face is being opened up on the lower 
bench of sandstone on the down stream side of the present opening. 
The heavy cover of overlying undesirable rocks makes this a rather 
poor location for a quartz sand quarry. Operations on the lower 
bench will necessarily have to be very limited, unless a large amount 
of waste material is to be handled. No glass sand is being produced 
at present, the sand being sold largely as furnace sand. The Ken- 
nerdell Sand and Manufacturing Company, however, when it operated 
this property sold some glass sand for making window glass, skylights 
and similar grades of glass. 

The plant is equipped with a gyratory crusher, and rolls for crush- 
ing the sandstone to sand. After being crushed the sand is passed 
through three screw washers and run into a flume, down which it 
passes to the railroad cars below. 

Warren County. 

In Warren Countv the Pottsville formation consists of three mem- 
bers namely": The Olean conglomerate at the bottom, the Sharon 
shale and the Connoquenessing sandstone at the top. 

The Olean is a coarse conglomerate, composed almost every where 
of well rounded pebbles of white quartz, ranging in diameter up to 
2i inches, although for the most part measuring 1^ inches or less. 
These pebbles are imbedded in a tine ground mass of quartz grains, 
and are cemented by iron oxide and silica. In Warren County it 
has a maximum thickness of about 50 feet, thinning out toward the 

.The Sharon shale member has a thickness of about 40 feet, and is 
composed o' 'k brown shales, with limonite nodules and a few 
thin sandstone layers. The Connoquenessing is uniformly a very 
coarse, saccharoidal white quartz sandstone, with a few small peb- 
bles in places. Poorly preserved plant stems are common in it. 
In thickness it ranges from 20 feet, or less, up to 100 feet. Outcrops 
of Pottsville sandstone are numerous in Warren County, but in 1914 
only one sand Company, namely the Warren Silica Company, re- 
ported any production of glass sand. The plant of the Althom Sand 
Company, one of the other sand operators of this county, was de- 
stroyed by fire during the summer of* 1914. 

VParren Silica Company. 

The mill of the Warren Silica Company is located near the depot 
at Torpedo, a station on the Dunkirk, Allegheny Valley and Pitts- 
burgh Railroad, which is leased by the New York Central and Hudson 
River railroad and operated by the Lake Shore and Michigan South- 
em railroad. The quarry is located about one and three-fourths miles 

78. United States Geological Surrex. Folio 1T2. 


from the mill and 265 feet above it on the upland of this portion of 
Warren County. It is connected with the mill by a narrow gauge 
railroad, owned by the company. At the quarry about 2 feet of 
soil occurs at the surface. Underneath this there are from four to 
thirteen feet of soil and broken rock, which is too iron stained to be 
of value for anything but the cheapest grade of sand. Below this 
lies a massive sandstone, varying in thickness from 12 to 25 feet. 
Most of this is a white quartzitic sandstone, which on crushing and 
washing yields a fairly good grade of glass sand. In places, how- 
ever, it has a pinkish tinge, due to the presence of iron oxide. At 
present the floor of the quarry consists of a bed of shale. Figure 1, 
Plate CI, shows a diagram of the working face, and Figure 2, a view 
taken in the quarry. The quarry is about 680 feet long. An analysis 
of «r sample of washed and dried sand showed the presence of .10% 
FejOj. It had a yellowish brown color. A screen test gave the 
following results: 

Screen Teat of Sand from Warren Silica Company Plant. 

Passed through a 10 mesh and caught on a 14 mesh sieve, .046 inches. .25 

Passed through a 14 mesh and caught on a 20 mesh sieve, .0328 inches. .27 

Passed through a 20 mesh and caught on a 28 mesh sieve, .0232 inches, 1.03 

Passed through a 28 mesh and caught on a 35 mesh sieve, .0164 inches. 5.80 

Passed through a 35 mesh and caught on a 48 mesh sieve, .0116 inches, 33.73 

Passed through a 48 mesh and caught on a 65 mesh sieve, .0062 inches, 34.62 

Passed through a 65 mesh and caught on a 100 mesh sieve, .0058 inches, 18.27 

Passed through a 100 mesh and caught on a 150 mesh sieve, .0041 inches, 3.32 

Passed through a 150 mesh and caught on a 200 mesh sieve, .0029 inches. 0.42 

Passed through a 200 mesh, 0.29 


The sandstone at the quarry lies horizontal, and the quality of 
most of it is excellent, but the site has the great draw back, in that 
there is such a thick cover of soil and broken and partially disinte- 
grated sandstone, badly stained by iron oxide, which must be re- 
moved, thus making quarrying operations very expensive. The par- 
tially disint^rated and iron stained sandstone can only be worked 
into the cheapest grade of sand. The plant of the Warren Silica 
Company is located near the Station at Torpedo. Plate CII shows 
its external appearance. The method of crushing the sandstone and 
washing the sand is somewhat different than that employed at other 
places. Instead of a jaw crusher a gyratory crusher is used. A 
Bartlett and Snow disintegrated of about 20 tons capacity per hour 
is employed to crush the broken sandstone into sand, in place of a 
chaser mill or wet grinding pan. Water is added to the sandstone 
in the disintegrator. The sand and water are run into long settling 
tanks. These are 36 feet long, 2J feet wide and 5 feet deep, with 
flat bottoms. They are inclined at an angle of 1^® from the hori- 
zontal. On one side, near the bottom, four inch spigots are placed 
every 18 inches to draw off the sand. The waste water and fine clayey 
material held in suspension are allowed to flow off near the top at the 

Ounfeqnifed m ana so. 1 


\ PinK 53 

Os."teqro*M 55. 

White 5Dnd5fwne. 

Vc'l.col ^ole 1_ 

Fig. 1. Diagram of working fnce nt qunrrj' of Warron Silica Co.. Torpcdi), I'n. 


operated by the Parthenum Silica Sand Company. This quarry is 
500 feet above the level of the Pennsylvania railroad track at this 
place. It is located on the north side of the first creek entering the 
Allegheny River above Thompson Run on the west side. A quarry 
face about 300 feet long, running nearly east and west, was opened 
up. At the west end there are two feet of soil cover and 18 feet of 
massive sandstone, with a few thin streaks of conglomerate. Near 
the middle there are two feet of soil and U feet of massive sandstone, 
with practically no conglomerate, while at the east end, 2 feet of soil 
overlies 10 feet of massive sandstone, underneath which there are 8 
feet of conglomerate. This conglomerate lense pinches out toward 
the west. It was left behind in the quarry as a bench. Most of the 
sandstone exposed is a white, nearly pure quartz sandstone, which is 
suitable for glass sand for window and similar grades of glass. It 
is of considerable better quality than that exposed in the quarry at 
Althom. The writer was informed that Vashed and dried glass 
S^nd was formerly produced from this quarry. 

Westmoreland County. 

In Westmoreland County outcrops of Pottsville sandstone occur 
along Chestnut and Laurel Ridges in the eastern part of the county. 
Along Chestnut Ridge'^ the formation has a thickness of from 75 to 
170 feet. It consists of two beds of coarse sandstone namely: The 
Homewood and Connoquenessing, which are separated by 10 to 15 
feet of sandy shale. In the vicinity of Derry, along Chestnut Ridge, 
the Homewood member of the Pottsville sandstone has been quarried 
for glass sand by the American Window Glass Company, and the 
Derry Glass Sand Company, while in the vicinity of Seward, in north- 
eastern Westmoreland County, where the Conemaugh River crosses 
Laurel Ridge, the Connoquenessing sandstone member in places is 
sufficiently pure quartz sandstone to be suitable for glass sand. 

American Window Glass Company. 

The sand plant of the American Window Glass Company is located 
at the southeast end of the town of Derry, ju«t beyond the town limits, 
on a small stream which has its source on the side of Chestnut Ridge. 
The sandstone quarry is located on the northwest side of Chestnat 
Ridge, on the north fork of this stream, about one and one-fourth miles 
above the mill. It is connected with the latter by a tram road. The 
quarry is about 405 feet above the mill in elevation, so that the cars 
can be let down by gravity. A hoisting engine has to be used, how- 
ever, to assist in returning the empty cars. Five loaded cars are 
let down at one time, while five empty cars are being hoisted. 

79. United SUtM Oeoloflcfll Surrey, Folio 110. 






J J" 

• J 



Fig. 2. View taken in abuve quarry. 


A working face of about 1000 feet long has been opened in this 
quarry. Figure 1, Plate CIV shows a diagram of the quarry, while 
Figure 2 is a view taken in the quarry. Five feet of soil and 25 
feet of nearly white, but rather hard, quartz sandstone occur at the 
south end. Near the middle there are from six to seven feet of 
soil, forty-five feet of nearly white sandstone, quartz sandstone, and 
fifteen feet of claj' and sandstone, badly stained by iron oxides and 
containing some thin, irregular streaks of coal. At the north end 
there are five feet of soil and forty-five feet of white quartz sand- 
stone. The best grade of rock is at this end of the quarry. Some- 
times the sandstone is stained pretty badly by limonite along bedding 
and joint planes. Only rock is sent to the miU. About one-half 
of the sand prepared from the output of the quarry is used in the 
manufacture of window glass by the An^pncan Window Glass Com- 
pany, the rest is sold as grinding sand to plate glass manufacturers. 
A sample of glass sand prepared at this plant showed .25% FcaOg on 
analysis. This sand has a xevj light brown color and contains oc- 
casional grains with coats of limonite adhering to them. A screen 
test gave the following results : 

Screen Analysis ol American Window Glass Company's Sand. 

Passed through 8 mesh and caught on 10 mesh, .065 inches 13 

Passed through 10 mesh and caught on 14 mesh, .046 inches, 76 

Passed through 14 mesh and caught on 20 mesh, .0328 inches, 1.63 

Passed through 20 mesh and caught on 28 mesh, .0232 inches 6.79 

Passed through 28 mesh and caught on 35 mesh, .01&4 inches, m. 14.76 

Passed through 35 mesh and caught on 48 mesh, .0116 inches 30.65 

Passed through 48 mesh and caught (m 65 mesh, .0082 inches, 23.62 

Passed through 65 mesh and caught on HiO mesh. .0058 inches 15.61 

Passed through 100 mesh and caught on 150 mesh, .0041 inches, 3.91 

Passed through 150 mesh and caught on 2i)0 mesh, .0029 inches 1.19 

Passed through 200 mesh, .75 


During the fall of 1914 some of the soil cover was being simply 
shoveled back from the working face onto ground from which it will 
later have to be removed if operations are continued at this site. 
Some of the soil is loaded into carts and dumped into worked out 
portions of the quarry. The rather thick cover of soil, the worthless 
nature of that part of the rock appearing along the lower portion of 
the working face near its center, and the iron stained character of 
much of the white rock, are all rather serious drawbacks, which de- 
tract considerably from the value of this quarry as a desirable source 
of glass sand. 

The plant is equipped with four eight-foot chaser mills, each of 
'which has a daily capacity of 200 tons of sand. This gives the plant 
a total capacity of 800 tons of sand per day when all the mills are in 
operation. Three of them are run by steam power, while the fourth 
is operated by an electric motor. Plate CV shows the flow sheet for 


this plant. The sand is all shipped wet, none of it being dried, al- 
though the plant is equipped with a Cummer dryer. 

Water for washing the sand is obtained from three deep wells, two 
of which are down 450 feet while the third has a depth of 500 feet. 
All the water from the small creek at the mill which the town of 
Derry does not require is also utilized. During the fall of 1914 a 
shortage of water necessitated the shutting down of a portion of the 


Derry Glass Sand Company. 

The plant of the Derry Glass Sand Company is located on a siding 
of the Pennsylvania railroad, about half way between Derry and 
Millwood, where a small stream cuts down the side of Chestnut ridge. 
During the fall of 1914 the Company was preparing to abandon its 
old quarrj\ A new one^vas being opened near the top of Chestnut 
ridge, a little over two miles southwest of the plant. This site is 
about 970 feet in elevation above the mill. Explorations have shown 
the presence of a thickness of about 45 to 50 feet of nearly white, 
massive quartz sandstone, with only three to four feet of cover. At 
the time of the writer's visit, in September, 1914, development work 
was just beginning at this place. 

The old quarry is about 136 feet lower down on the side of the ridge. 
The sandstone at this place dips 8^° to the northwest. Therefore, 
as the quarry was opened in a southeast dii^ection, back into the hill, 
the white^ quartz sandstone rose higher and higher, until finally it 
gave out. Figure 1, Plate CVf shows a view in the quarry, illus- 
trating this condition. A bed of shale and dark colored sandstone^ 
with occasional streaks of coal, underlies the white quartz sandstone. 
It was not feasible to continue operations at this site along the strike 
on account of existing topograi)hic features and the increase in soil 
covering overlying the sandstone. For these reasons the quarry will 
be abandoned. 

The sandstone is loaded into cars which are let down an inclined 
tramway leading to the mill. An electric hoist is used to assist in 
returning the empty cars. Tlie air compressor at the quarry, to 
operate the drills, is also operated by electric power. 

The plant is equipped with two six-foot chaser mills, of 125 tons 
capacity each, giving the plant a total capacity of 250 tons of sand 
per day. Plate CVII gives the flow sheet of this plant, and Figure 
2, Plate CVI is a view showing its outside appearance. All of the 
sand is shipped wet. Xo glass sand is shipped at present, although 
sand suitable for the manufacture of window glass can be prepare^f. 

Millwood Glass Sand Company. 

The plant of the Millwood Glass Sand Company is located on a 
small creek at the station of Millwood on the Pennsvlvania railroad. 


Fig. 2. Plant of Dcrry GIusb Sand Coiiiiiuiiy at Di'i'i 


• • 


The quarry is located about 2000 feet up the valley of this creek, on 
the northeast side. A narrow gauge track, with a sufficient gradient 
to allow the loaded cars to run by gravity, connects it with the mill. 
Mules are used to haul the empty cars back to the quarry. 

A quarry face about 60 feet long, with maximum height of about 
25 feet, has been opened. There are from two to two and one-half 
feet of soil overlying the sandstone. The upper one-half of the sand- 
«tone is badly fractured and considerably discolored by iron oxides, 
while the lower one-half is a nearly white quartz sandstone. It is 
rather hard. The depth of cover will probably increase as the face 
is worked back into the hill. 

The plant is equipped with a jaw crusher and seven-foot chaser 
mill. The latter has a capacity of 80 tons of sand per ten hours with 
the type of rock quarried. Four screw washers have been installed. 
The niachineiy is operated by electric power. Only building and 
grinding sand hjive thus far been prepared. 

On the west flank of Laurel Ridge, in the vicinity of Seward, in 
Dortheastern Westmoreland county, the Connoquenessing member of 
the Pottsville formation consists of a friable quartz sandstone suit- 
able for certain grades of glass sand, such as that U8<*d in the manu- 
facture of window and bottle glass. The following analysis of a 
sample from this locality, made by A. J. Phillips, is quoted by W. 
<?. Phalen in Folio 174 of the United States Geological Sur\'ey. 

Analysis of Sand from Near Seward, Westmoreland County. 

SiOs 97.54 

AI2O3 - 81 

FojOs 09 

MkO _ .06 

C'O. 1 1 (J4 

Nn:,() .02 

K,0 16 

ILO nt 1(!0 : _ 03 

Jtriiitlon loss, .49 

Ifrf) 24 

The writer did not have the oj)j)(»rtnTiity to visit thi.*^ localitv. 





River Terrace Sand. 

Sand for glass making has been obtained from deposits occurring 
along the abandoned channels of the Monongahela and Youghiogheny 
Rivers in southwestern Pennsylvania*^®. River sand of this type was 
formerly secured from the terrace opposite Bellevernon*^ and from 
the old valley back of the same town. These terraces were fonneil 
by the Monongahela river during the Pleistocene epoch, and were 
later abandoned. A similar deposit was at one time worked at 
Perryopolis on the Youghiogheny River. These sands are generally 
of very poor quality, on account of the high iron content, and were, 
therefore, only utilized in the manufacture of the chtjaper grades of 
glass, such as bottle glass. At the present time no glass sand is 
being derived from these deposits. 

The Tuscaroru Sandstone as a Possible Source of Glass Sand. 

The Tuscarora sandstone of central Pennsylvania (the so-called 
Medina of the Second Geological Survey of Pennsylvania) has at- 
tracted some attention as a possible source of glass sand. It is fre- 
quently a very pure quartz sandstone, analyzing over 98% silica, but 
it is usually veiy thoroughly cemented and recrystallized into a vit- 
reous quart zite, which is extensively quarried in central Pennsyl- 
vania as ganister for the manufacture of silica brick. This rock on 
crushing does not break up into its component grains, as does a de- 
sirable sandstone for glass sand, but instead it breaks into fragments 
of various sizes, often across the grains themselves instead of along 
their contacts. In reducing these fragments to the size necessary for 
glass sand a great deal of fine powder is produced, and the operation 
is an expensive one, as compared with the crushing of ordinary sand- 

Another peculiarity of the Tuscarora sandstone, as compared with 
the Oriskany, is that the former does not w^eather as readily to a 
friable sandstone or loose sand as does the latter, although such action 
does take place to a certain extent. J. P. Lesley^^ has called atten- 
tion to such an occurrence along Blue Mountain, in Schuylkill County, 
near Drehersville, W'here white sand had collected along the crest of 
the mountain through the disintegration of the more loosely grained 
layers of the Tuscarora sandstone. These sands furnished silica 
for glass manufacture. 

80. United States Geologrlcal Sxurey, Folio 82. p. 21. 

81. United States Geologrlcal Sorrey. Folio 94, p. 19. 

^d Geological Surrey of Pennsylvania, Report F, page xxxl. 


The Tuscarora in the vicinity of Hyndman, in south central Penn- 
sylvania, along the main line of the Baltimore & Ohio Railroad, is 
an exceptionally pui*e quartzite and has, therefore, attracted some 
attention as a possible source of glass sand. An analysis of a sample 
collected from an abandoned gauister quarry on the hill above the 
Pennsylvania railroad bridge at this locality showed the following 
composition : 

Annlysis of Tuscarora Sandstone from Near Hyndman, Penna. 

RiO. 99.54 

AlaOj - • .35 

FeoOs 09 

Mt'O _ .06 

CiiO 19 

HA> .25 

Ti(>2. — — - __ _ 03 

- 100.51 

The formation dips 2o^ to the northwest and a thickness of 80 
feet of the sandstone is expo.*ied. With the exception of several thin 
shale seams the formation is a surprisingly pure white quartzite. If 
it were not for its hardness this rock would undoubtedly yield a good 
grade of glass sand. 

The >^ilica Sand Company of Pittsburgh, a number of years ago, 
opened- a quarry for glass sand in the Tuscarora sandstone on the 
west side of Cacapon Mountain iu West Virginia, one and one-half 
miles west of Berkley Springs, on the road to Great Cacapon. A 
pit 20 feet wide and 150 feet long was quarried into the face of the 
hill, and tin up-to-date sand plant for treating the sandstone was 
erected. The enterprise had to be abandoned, however, on account 
of the great hardness of the quartzite"'. G. P. Grimsley gives the 
composition of the quartzite as follows: 

Analysis of Tuscarora Quiirtzite from Caoapon Mountain, Vi'eat Virginia. •* 

SiO^. y9>n 

AI.Oi .-3 

Voj.h. _.. m 


It is not likely that the Tuscarora sandstone will yield any large 
amounts of glass sand in Pennsylvania in the near future, since large 
quantities of more desirable sandstones, equally favorably situated, 
are still available. A very careful and detailed investigation should 
always be made by parties contemplating the erection of a plant to 
produce glass sand from the Tuscarora sandstone, before any large 
sums of money are spent in purchasing property and equipment as in 
most cases it will probably be found that the quartzite is not suitable 
for crushing economically into glass sand. 

83. rnftM Stfltcs Gpolojrlcal Surrey. Frlio 179. p. 21. 

84. West Virginia Geological Survey, V<»luTne 4, p. 39C. 



The Following References Were Consulted in the Prepari-^tion of Thia 


Glass and Glass Manufacture. 

Berry J C.W. The needs of the glass manufacturer in the way of 
refractories. Transactions American Ceramic Society. Volume 
XVI, 1914, pp. 101-108. 

Biser, Benjamin F, Elements of Olass and Glass Making, 1809. 
Chemically revised by eT. A. Koch, 1915. 

Brockhank, C. J. An investigation of the surface devitrification of 
glasses under thermal after-treatment. Transactions American 
Ceramic Society, Volume XV, 1913, pp. GOO-606. 

Chance, Henry, On the manufacture of crown and sheet glass. Lou- 
don, 1883. 

Commoner and Ghtssirorker. Some glass formulae. Volume XXI, 
Number 11, 1899. 

Commoner Publishing Company, American Glass Trade Directory, 

DraUe, Robert. Die Glasfabrikation. Berlin, 1911. 

Egleston, T. The uses of blast-furnace slags. Transactions Ameri- 
can Institute of^ining Engineers. Volume 1, 1871-1873, p. 210. 

Fenneman, X. M. Clay resources of the St. Louis District, Missouri. 
United States Geological Survey, Bulletin 315, 1007, pp. 315-321. 

Frink, /?. L. The effects of alumina on glasfj. Transactions Ameri- 
can Ceramic Society, Volume XI, 1009, pp. 09-102. 

Frink, /?. L. Some fallacies and facts pertaining to glass making. 
Transactions American Ceramic Society, Volume XI, 1909, pp. 

Frink, R. L. Barium in glass. Transactions American Ceramic 
Society, Volume XII, 1910, pp. 370-375. 

Frink, R. L. Re(piisite properties of glass for mechanical manipu- 
lation. Transactions American Ceramic Society, Volume XII, 
1910, pp. 585-613. 

Frink, R. L. The requirements of glass for bottling purposes. Trans- 
actions American Ceramic Society, Volume XV, 1913, pp. 700-727. 

OeUtharp, Frederick. Heat balance of a [date glass furnace. Trans- 
actions American Ceramic Society, Volume XII, 1910, pp. 621-627. 

Gehtharp, Frederick. Some chemical reactions of interest to the 
plate glass chemist. Transactions American Ceramic Society, 
^olume XIV, 1912, pp. 642-654. 


4jel8tharp, Frederick. 8ome chemical reactions of interest to the 
plate glass chemist. Transactions American Ceramic Society, 
Volume XV, 1913, pp. 585-590. 

4}ehth(irp, Fredcrcik and Parkinson, J. C, The limits of proportions 
of soda-lime glasses. Transactions American Ceramic Society, 
Volume XVI, 1914, pp. 109116. 

Werner, Raimnnd, Die Glasfabrikation. Zweite Auflage, 1897. 

Ressner, Frank M, The glass maker's handbook, 1891. 

Oilhnder, James, Glass. Industrial Chemistry, edited by Allen 
Rogers and Alfred B. Aubert, 19ia, pp. 313-328. 

Olos.^ Mannjacturcs. Census of the United States, Volume X, 1913. 

■Orajton, Chas. O. The art of pot making. The Glass Worker, June 
8, 1912, pp. 17-19. 

Ealik, Johann, Handbuch der Glasfibrikation. 1 Band. 1908. 

Horcstadty H. Jena glass and its scientific and industrial applica- 
tions, translated and edited by J. D. Everett and Alice Everett. 

Kcnif William, The mechanical engineer's pocket book. 1910. 

Knotc, J, M. Behavior of an acid glass in a tank furnace. Trans- 
actions American Ceramic Society, Volume XIV, 1912, pp. 655-664. 

Linton, Robert. Glass. The Mineral Industry for 1899. Volume 
VIII, pp. 234-363. 

Miller, J. C. Power Gas and Gas Producers. 1910. 

Mining and Scientifi<; Press. Thallium. .January 2, 1915, p. 33. 

Minton, Roy //. The manufacture of refractory materials for glaj^ 
works c(»nstruction. Transactions American Ceramic Society, 
Volume VIII, 1906, pp. 353-363. 

"Safiel, Oskar. The mechanical appliances of the chemical and metal- 
lurgical industries. 1908. 

Kof/el. Oskar. Producer Gas. Industrial Chemistr\% edited by Al- 
len Roarers and Alfred B. Aubert. 1913, pp. 89-110. 

Ortf*n, Edward, Jr. Glass pot manufacture. The clay working in- 
dustries of Ohio. Geological Survey of Ohio, Report Volume VII, 
pp. 231-233. 

Peffers, IT. B. Glass. Bureau of the Census. Manufactures. Part 
III, 1905. 

Pellat, Apsley. The curiosities of glass making. London, 1849. 

Ries, Heinrieh. The Kaolins and fire clays of Europe. United States 
GiH^logical Sun'ey. Nineteenth Annual Report, Part VI, 1898, 
pp. 377-467. 

Rirs, ITeinrirh. Glass pot clays. The clays of New York, New York 
State Museum, Bulletin XXXV, 1900, pp. 786-787. 

Rosenhain, Walter. Glass manufacture, 1908. 



Beaver, Kenneth. Refractory materials. The Mineral Industry dur- 
ing 1914, Volume XXIII, pp. 900-905. 

Silverman^ Alexander. The use of barium compounds in glass* Jour- 
nal of the Society of Chemical Industry, Volume XXXIV, April 
30, 1915, pp. 399402. 

Sifiger, Felix. Influence of alumina on the fusibility of glasses. 
Keram Rundschau, Volume XXIII, 1915, pp 65-66, 78-79, 95-96, 

Smully Judson O. The causes of opallescence of glass. Journal of 
the Society of Chemical Industry, Volume XXXIV, Apnl 30, 1915, 
pp. 402-405. 

Sprechsaal, Von der werking des Arseniks. August 29, 1912, 45 
Jahr, gang No. 35, pp. 531-532. 

Takashashiy T. Some experiineuts on the color of soda-lime glass. 
Transactions American Ceramic Society, Volume XIII, 1911, pp. 

Thorpe, Sir Edward, Glass. Dictionary of applied chemistry. Vol- 
ume 11, 1912. 

Ts('hcn>>ncr, E, Handbuch der Glasfabrikation, Furtte Auflage, 1SS5. 

M^ceks, Jos. D. Report of the manufacture of glass. Final report 
on the 10th Census, Volume II, 1883. 

WeeJkS, Jos, D. Glass materials, Mineral Resources of the United 
States, Calendar years 1883-1884, 1885, pp. 958-977. 

Glass Sands in General. 

Berkcy, Chas, P. Paleogeography of Saint Peter time. Bulletin 
Geological Society of America, Volume XVII, 190G, pp. 229-250. 

Burchard, Ernest F. The requirements of sand and limestone for 
glass making. United States Geological Survey, Bulletin 285, 
1906, pp. 452-458. 

BurcJiardy Ernest P, Glass sand of the middle Mississippi Basin. 
United States Geological Survey, Bulletin 285, 1906, pp.. 459-472. 

Burchard, Ernest F, Glass sand. United States Geological Sur- 
vey. Mineral Resources of the United States. Calendar year 
1906, pp. 993-1000. 

Burchard, Ernest F, Notes on various glass sands, mainly unde- 
veloped. United States Geological Survey, Bulletin 315, 1907, pp. 

Burchard, Ernest F, Glass sand, other sand and gravel. United 
States Geological Survey. Mineral Resources of the United States, 
Calendar year, 1911, Part II, Xon Metals, pp. 585-638. 

Buttram, Frank, The Glass sands of Oklahoma. Oklahoma Geologi- 
cal Survey, Bulletin X, 191?. 

Clarke, F. W, The data of geochemistiy. Second edition. United 
States Geological Sun-ey, Bulletin 491, 1911. 


Condity D. Dale. The petrographic character of Ohio sands with re- 
lation to their origin. Journal of Geology, Volume XX, 1912, 
pp. 152-163. 

Dana, James D. Manual of Mineralogy and Petrography, 12th 
edition, 1906. 

Dolhear, S. H, Non-metallic products. Mining and Scientific Press, 
October 16, 1915. 

Fennery Clarence N. The various forms of silica and their mutual 
relations. Journal of the Washington Academy of Science, De- 
cember 4, 1912, Volume II. 

Frink, Robert L. Concerning glass sand. The Glass Worker, Vol- 
ume XXXI, No. 9, 1912, p. 2. 

Fuller, Myron L, Etching of quartz in the interior of conglomerates. 
Journal of Geology, Volume X, 1902, pp. 815-821. 

OrabaUy A. W, and Sherzcry W, H. The Monroe foniiation of south- 
ern Michigan and adjoining regions, Michigan Geological and Bio- 
# logical Survey, Publication 2, Geologic Series 1, 1910. 

GrahaUy A. W, Principles of Stratigraphy, 1913. 

Grinislcf/y G, P, The glass sand indnstiT in West Virginia. The Min- 
eral Industry during 1907, Volume XVI, pp. 4G5-4G9. 

Grimslvy, G. P. Ilistory of the glass sand industry in West Virginia, 
West Virginia (Teological Survey, Volume IV, 1909, pp. ;]7r)-390. 

HayeSy C. Willard, Solution of silica under atmospheric conditions, 
Bulletin Geological Society of America, Volume VIII, 1897, pp. 

Kii)nnnl, U. B. and (luge, R. B. The glass sand industry of New 
Jersey. Geological Survey of Xew Jersey. Annual Report of 
the State Geologist for the year 190G, pp. 77-9(5. 

Kiimmely Henry B. Glass sand. The Mineral Industry for 1913, 
pp. GG6-672. 

Lesley, J. P. Laurentian, Huronian, Cambrian and Lower Silurian 
formations, Second Geological Survey of Pennsylvania, Final Sum 
mary Report, Volumel, 1892. 

Merrill, George P. Sand for glass making, the non-metallic minerals, 
2nd edition, pp. 419-420. 

Newl^nd, David JI, Glass sand. The Mining and Quariy Industry 
of New York State, Xew York State Museum, Bulletin 9, 1905, pp. 

Randolph, Beverly <S. The silica sand industry. Engineering and 
Mining Journal, December 28, 1907, pp. 1211-1212. 

Smythy C. H, Replacement of quartz by pyrite and corosion of quart2 
pebbles, American Journal of Science, 4th Series, Volume XIX^ 
1905, pp. 277-285. 


;Ston€, Ralph W. Production of glass sand in 1912. United States 
Geological Survey, Mineral Resources of the United States, Calen- 
dar'year 1912, Part 2, Non metals, pp. 621-636. 

^tose, George, The glass sand industry in eastern West Virginia, 
United States Geological Survey, Bulletin 285, 1906, pp. 473-475 

United States Geological Survey. Analyses of glass sands from Penn- 
sylvania. Mineral Rescyurces of the United States, Calendar year 
1000, Part 2, Non metals, pp. 535-538. 

The Oriskany Formation. 

Africa, J. Simpson, History of Huntingdon and Blair counties, Penn- 
svlvania, 1883. 

Btitts, Charles, The Devonian section near Altoona, Pennsylvania, 
Journal of Geology, Volume XIV, 1006, pp. 618-630. 

Butts, Charles, Geology of the Birmingham, Alabama, quadrangle, 
United States Geological Suney, Folio 175, 1910. 

Butts, Charles, Geology and mineral resources of Jefferson county, 
Kentucky, Kentucky Geological Survey, Series 4, Volume 3, Part 
2, 1015. 

Clarke, John M\ Lenticular deposits of the Oriskany formation ir 
New York, Proceedings of the American Association for the Ad- 
vancement of Science, Volume XLIX, 1000, pp. 18S8. 

Clarke, John M. and Luther, D. David, Geologic Map of the Tully 
Quadrangle, New York State Museum, Bulletin 82, 1005. 

<^la7'ke, John M, Early Devonic History of New York and eastern 
North America, New York State Museum, Memoir IX, 1008. 

Clay pole, E, W, A preliminary rejiort on the paleontlogy of Perry 
County, describing the order and thickness of its formations and 
its folded and faulted structui^e. Second Geological Sur\*ey of 
Pennsylvania, Report FF, 1885. 

Cochran, Joseph. History of Mifflin County, 1870. 

Darton, V. //. Notes on the stratigraphy of a portion of central Ap- 
palachian Virginia, American Geologist, Volume X, 1802, pp. 10-18. 

Darton, N. H. Stanton Folio, Virginia-West Virginia, United States 
Geological Survey, 1804. 

Darton, N. H. Geological relations from Green Pond, New Jersey, to 
Skunnemunk mountain. New York, Bulletin Geological Society of 
America, Vol. V, 1804, pp. 367-304. 

Detrees, John IT. Report of progress in the Juniata District on Fos- 
sil Iron Ore Beds of middle Pennsylvania, with a report of the 
Aughwick Valley and East Broad-Top District by C. A. Ashburner, 
Second Geological Survey of Pennsylvania, Report F, 1874-1875. 

D'hivilliers E. V, The Geolojxy of Centre County, Second Geological 
Survey of Pennsylvania, Report T 4. 


Foerste, A. F. Silurian and Devonian limestones of Western Ten- 
nessee. Journal of Geology, Volume XI, 1903, pp. 554-583 and 

Orabau, A. W, Guide to the geology and paleontology' of the Scho- 
harie valley in eastern New York. New York State Museum, Bul- 
letin 9, 1900. 

Hartnagel, C. A. Classification of the geologic formation of New 
York, New York State Museum, Handbook 19, 1912, 

Hayes, Chas, Will^jrd. Geology of a portion of the Coosa Valley in 
Georgia and Alabama. Bulletin Geological Society of America,. 
Volume V, 1894, pp. 4U5-480. 

Eaycs, Chas, Willard. Gadsden, Alabama, Folio, United States Geo- 
logical Suney, 189G. 

KindlCf Edward M. The Devonian fossils and stratigraphy of In- 
diana, Department of Geology and Natural Resources of Indiana, 
XXV Annual Report, 1900, pp. 529-763. 

Kindle, Edward J/. Faunae of the Devonian section near Altoona,. 
Penna., Journal of Geology, Volume XIV, 1906, pp. 631635. 

Kindle, Edward J/, et ah Middle and Upper Devonian. Maryland 
Geological Sun^ey, 1913. 

Kiimmel, Henry B,' Geological Section of New Jersey. Journal of 
Geology, Volume XVII, 1909, pp. 351-379. 

Lesley, J, P. A summary description of the Geology of Pennsylvania, 
describing the Upper Silurian and Devonian Formations. Second 
Geological Survey of Pennsylvania, Final Summary Report, Vol- 
ume 2, 1892. 

Luther, D, D, Geologic map of the Buffalo quadrangle. New York 
State Museum, Bulletin 99, 1906. 

Miller, Benjamin L. Mineral Pigments of Pennsylvania. Topo- 
graphic and Geologic Survey of Pennsylvania, Report No. 4. 

Piatt, Franklin, The Geology of Blair County. Second Geological 
Survey of Pennsylvania. Report T, 1S81. 

Rogers, W. B, Unconformity at the base of the Oriskany. American 
Journal of Science, Volume XLIII, 1842, p. 181. 

Sehurchert, Chas, Lower Devonic asj)ect of the Lower Helderberg and 
Oriskany formations. Bulletin Geological Society of America, Vol- 
ume XL, 1900, pp. 241-332. 

Sherzer, W, H. Geological Report on Monroe County, Michigan. 
Geological Survey of Michigan, Volume VII, Part 1, 1900. 

Staufer, Clinton R, Middle Devonian of Ohio. Geological Survey of 
Ohio, Bulletin X, Fourth Series, 1909. 

Stevenson, J. J, The geology of Bedford and Fulton Counties. Sec- 
ond Geological Survey of Pennsylvania. Report T 2, 1882. 


Stose, George W. and Stcartz^ Charles K, Pawpaw-Hancock Folio, 

No. 170, United States Geological Suney, 1912. 
SwartZf C, K. et ah Lower Devonian. Maryland Geological Survey, 

WcUery Stuart, Th^ composition, origin and relationship of the Cor- 

niferous fauna in the Appalachian province of Noi*th America. 

Journal of Geology, Volume X, 1902, pp. 423432. 
Weller, Stuart. Notes of the geology of southern Calhoun county. 

Illinois State Geological Survey. Bulletin 4, 1907, pp. 219-233. 
White, I, C. The geology of Pike and Monroe Counties. Second 

Geological Siir\'ey of Pennsylvania. Report G 6, 1881. 
White, L C, The geology of Huntingdon County. Second Geological 

Survey of Pennsylvania, Report T 3, 1885. 
Williams, Henry Shalcr, The Devonian section of Ithaca, New York. 

Journal of Geolog>', Volume XIV, 190G, pp. 579-598. 

Pottsvllle Formation. 

Ashley, George H, and Glenn, L. C. Geology and mineral resources of 
part of the Cumberland Gap coal field of Kentucky. United States 
Geological Sur\ey, Professional Paper No. 49, 1906. 

Campbell, Marius R. The Masontown-Uniontown FoUo, No. 82, 
United States Geological Sun^ey, 1902. 

Campbell, Marius R, The Brownsville-Connellsville Folio, No. 94, 
United States Geological Survey, 1903. 

Campbell, Marius R. The Latrobe Folio, No. 110, United States Geo- 
logical Survey, 1904. 

Gardner, James H, The Broad-Top Coal Field of Huntingdon, Bed- 
ford and Fulton counties. Topographic and Geologic Survey of 
Pennsylvania, Report X, 1913. 

Lesley, J. P. et al. Carboniferous formations. Second Geological 
Surrey of Pennsylvania, Final Summary Report, Volume 3, 1895. 

Phalen, W. C. The Johnstown Folio, No. 174. United States Geo- 
logical Survey. 

Shaw, E. W., Lines, E. F, and Munn, M, J. The Foxburg-Clarion 
Folio, No. 178. United States Geological Survey, 1911. 

Stevenson, J, J, Formation of coal beds. Proceedings of the Ameri- 
can Philosophical Society, \'olume L, 1911, Volume LI, 1912, Vol- 
ume LII, 1913. 

White, David. The stratigraphic succession of the fossil floras of 
the Pottsville formation in the Southern Anthracite coal field^ 
Pennsylvania. United States Geological Survey, Twentieth Annual 
Report, Part 2, 1898-1899, pp. 749-929. 

White, L C. Report on Coal. West Virginia Geological Survey, 
Volume 2, 1903. 

White, I, C. Supplementary Coal Report, West Virginia Qeologica 
Survey, Volume 2A, 1908. 




Aci<l oxides , 3^ 

Acids , action of on glass , 30 

JLlkalics , 68 

action of on glass , 30 

Althom Sand Co., 257 

Alumina , 79 

occurrence in glass sands 50 

American Window Glass Company's glass sand plant at Derry li5S 

Annealing glass, 39,125 

kilns or ovens , 125 

Arsenious acid , 67,80 

Atmospheric influence on glass 30 


Barivim oxide , 76 

Batch , composition of, 00 

mixing of, 76 

preparation of, 90 

bottle glass, 92 

lead flint 92 

plate glass , , 91 

window glass , ; 90 

Bedford County, Oriskany sand deposits in 220 

Benrath's classification of glasses, 28 

Bibliography, glass and glass manufacture, 2<34 

glass sands in j:»ii«'i;]! . 2<»t> 

Oriskany formation 268 

Pottsville formation , 270 

Blair County, Oriskany glass and deposits in , 222 

'Blake crusher, 57 

Blown glass , '. 132 

Bl»e colored glasj , 85 

Boric acid , 87 

Bottle glass 128 

analyses of, 24 

batches, 92 

Bradley gas producer, 103 


Calcium oxide in glass sands, 53 

Calcium phospate, 89 

Carbon County, Oriskany glass sand deposits in, 222 

'Carbon dioxide, action on glass, 31 

Carlin*s Sons Co., Thomas, 20 

-Carnegie Institute of Technology, - 19 




Ct^ntro County, Oriskauy glass sand deposits in 222* 

Cerium oxide , 87 

Chaser mill , 57 

Chemical properties of glass , 29 

Chronium oxide 86 

Chili saltpetre, 81 

Clarifiicrs 80 

Classification of glasses, 27 

Clearfield County, Pottsville glass sand deposits in , 240 

Coal fields of Pennsj'lvania .^ 105 

Cobalt oxide , 85 

Cochran, Geo. W., 20 

Coloring agents , 84 

Columbia Works of the Pennsylvania Glass Sand Co 19ft 

Copper oxide 85,8<5,8J> 

Cords in glass 124 

Crystal Sand Co 213.217 


Decolorizing agents , 82 

Density of glass , 3^ 

Derry (Jlass Sand Co., 2«<> 

Devitrification, 29,124 

Disintegrators , sand 61 

Dispersion in glass, 34 

Dryers , sand 5^ 

Dry grinding pans, 03 

Duff gas producer 103 

Dunbar Furnace Co 245 


Eartherton , II. A. , v . 2f> 

Electrical proiierties of glass, 35 

Elk County, Pottsville glass sand deposits in 240 

Enterprise Works of the Pennsylvania Glass Sand Co., 211 


Falls Creek Stone and Sand Co., 241> 

Fayette County, Pottsville glass sand deposits in , 24^ 

Ferric oxide , «S7 

Ferrous oxide , 85 

Fining 120.121 

Fire clay , ' K^ 

Fire clay of St. Louis, Missouri, district , V^ 

Flint, ''^ 

Flint clay from Mineral City, Ohio HWi 

Flourine preparations, ^^ 

Foaming , 12^ 

Forest County, Pottsville, glass sand deposits in, 24T 

Fox Silica Sand and Stone Co 241 

Fuel , 9T 


Furnaces for the fusion of glass, 106 

Fusibility of glass, 30 

Fusion 120 


Gall ; 122 

Gas, natural, 97 

Gas , producer, 100 

Geologic eras and poriotls, 150 

Gelstharp and Paikinson*8 triaxial diagram for lime soda glass, 25 

Glass, action of acids on , 30 

action of alkalies on, 30 

action of carbon dioxide on, 31 

action of hydrofluoric acid on , 30 

action of light on, 32 

analyses of, 22,23,24 

annealing of, 37 

behaviour at high temperatures, 32 

chemical properties of, 29 

classification of, 27 

composition* of , 22 ' 

definition of, 21 ^ 

density of, 33 

devitrification of, ' 29 

dispersion in , 34 

electrical properties of, 35 

fusibility of 36 

Gelstharp and Parkinson's triaxial diagram, 25 

hardness of, 34 

index of refraction , 34 

lustre of, 34 

mechanical properties of, ' 34 

optical properties of, 33 

physical properties of, 33 

processe^f working, ^ 128 

production in Pennsylvania, . . . . : 147 

resistance to atmospheric influences, 30 

thermal properties of 35 

transparency of, 33 

Tschenschner's formula for normal , 25 

batches , method of calculating, 93 

gall 123 

manufacture, raw materials of, 44 

pots, manufacture of, 110 

pot clays, occurrence of 106 

analysis of, from Lay ton Station, Fayette County, Pa., 108 

sand deposits, examination of, 66 

origin of, ; . . . . 43 

Oriskany, .^^ 163 

Pennsylvania , 149 

Pottsville, 236 

sand industry of Pennsylvania, location of, 149 

sands , alumina in , 50 



cnldum oxide in , 53 

definition of, 19 

impnritico in 49 

iron in » 52 

magnesium oxide in , 53 

preparation for market, 56 

preparation for market iu Central Pennsylvania, 173 

size and shape of grains, 54 

titanium oxide in , 54 

washing, 56 

water in, 53 

Gocella Stone and Sand Co. , 250 

Gold, 88 

Grafton, Chas. 20 

Green colored glass, 85 

Gross-Almarode fire clay, 109 


Hardness of glass, 84 

Hatfield Works of the Pennsylvania Glass Sand Co. , .- 215 

Hughes producer, 104 

Hummel Sand Co., 193,200 

Huntingdon County, history of glass sand industry in , 202 

undeveloped areas of Oriskany glass sand in, 201 

Hydrofluoric acid, action on glass, 30 


Index of refraction of glass, 34 

Iron in glass sands, 52 


Jefferson and Clearfield Stone and Sand Co., 250 

Jefferson County, Pottsville glass and sand deposits in, 249 

Juaniata White Sand Co., <. 193.199 

Juaniata works of the Pennsylvania Gla^ Sand Co., 21-^ 


Keystone Works of the Pennsylvania Glass Sand Co 195 

Knapps' classification of glasses , 27 

Kummel and Gages' screening tests on sands, 64 


Lead flint batches 9*J 

glass, analyses of, 24 

Lead oxide, » 88 

Le Blanc process, 68 

Lchrs, 126 

Lewistown Foundry and Machine Co. , 20 

Light, action of on glass 32 

Lime, 73 

flint batches 91 

glass, analyses of 23 


Limestone, 78 

impurities in , > 7i 

Lintons' classification of gliisi^eu, 1!8 

Lithium oxide , ' Vi 

Lubbers' cylinder drawing machine, 138 

Lustre of glass, 34 


Magnesia 76 

Magnesium oxide in glass sands, 53 

Magnetic separator, . •. 64 

Maganese dioxide, 82,84 

Mapleton Works of the Pennsylvania Glass Sand Ck>. , 103 

McKcan County » Pottsville Glass sand deposits in, 262 

Mechanical properties of glass, 34 

Mifflin County, history of glass sand industry in, 211 

Oriskany glass sand deposits of, 213 

Undeveloped areas of Oriskany glass sand in, 218 

Miller's Sand Mine, John, 218 

Millwood Glass Sand Co., 260 

Monroe County, Oriskany glass sand deposits in, 223 


Natural gas, 97 

analyses of, 98, 101 

mode of occurrence, 98 

in Pennsylvania , •. . . 99 

Nickel oxide 103,85 

Nitre, 81 


Opacifiers, 80 

Opal 40 

Optical glass, : 24,143 

properties of, ^ 33 

Oriskany formation, bibliography, 268 

formation, character and distribution, 151 

formation , geologic history of, 158 

glass sand deposit 163 

glass sand deposits in Pennsylvania , 176 

sandstone, characteristics due to conditions of original deposition , 163 

characteristics due to secondary changes , 166 

examination for glass sand, 174 

Kingston , New York, 153 

Owens automatic gathering and blowing machine, 130 


Parthenum Silica Sand Co 257 

Pennsylvania Glass Sand Co., 193,213 

Phillips and McLaren Co., 20 

Phosphoric acid , 67 

Physical properties of glass, 33 



Pittsburgh Plate Glass Go/s glass sand plant at Keuncnicll , 252 

Pittsburgh White Sand CJo., \ 193,107 

Plate Glass 139 

analyses of, 23 

batches, 91 

Potassium oxide, 72 

Pots, glass, 106 

furnace, 114 

PottsviUe formation, 224 

bibliography, 270 

character and distribution , 224 

geologic history of, 231 

preparation of glass sand from, 237 

glass sand deposits, 235 

glass sand deposits in Pennsylvania, 239 

glass sand deposits examination of, 238 

Pressed glass, 132 

Producer gas 100,101 

analyses of, 08, 101 

composition of, 101 

Pyrometers, 124 


Quartz, chalcedonic varieties of, 39 

chemical properties of, 41 

ground, 05 

jaslkiry varieties of, 40 

occurrence of, 4'2 

physical properties of, 41 

vitreous varieties of, 44 

Quick lime, 75 

Quay. J. G., 20 


Raw materials of glass manufacture, 44 

acidic oxides, 44 

alkalies, 68 

alumina 70 

arsenious acid, 77 

barium oxide, 7(S 

boric acid , 77 

clarifiers, 80 

coloring agents, 84 

decoloring agents, 82 

igneous rocks, 79 

lead oxide, 78 

lime, 73 

lithium oxide, i 73 

magnesia, 76 

opacifiers, : . 89 

phosphoric acid, 07 

potassium oxide, 7'J 

silica , 44 

Blag 7?) 



sodium oxide, 68 

strontium oxide, 77 

thalHum, 70 

line oxide, 77 

Red colored glass, 88 

Ridgway-Croyland Silica Sand Co., 243 

Ridgway Sand and Stone Company 242 

River terrace sand for glass making, 263 

Rolled glass, 130 


Salt cake, 68,72 

Saltpetre, 81 

Sand disintegrators, 61 

dryer, 69 

plants, cost of, 61 

washers, 58 

washing device, • 62 

Scholes, Dr. S. R., 20 

Screening sand, 60 

Screens, 65 

Seedy glass, 124 

Selenium, 84,89 

Silica, 44 

brick, 18 

Silica Stone and Sand Co., 261 

Silver 87 

Slaked lime, 69 

Soda, ash, <J8 

nitre, 81 

Sodium oxide, 88 

Solvay process, 70 

Spring Creek Glass Co., 248 

Standing off, 122 

Stevenson, W. P., 20,213 

Stones in glass, 124 

Striae in glass 124 

Strontium oxide, 77 

Sufphnr, 87 


Tank blocks, IW 

furnaces, 117 

ThaUlum , 79 

Thermal properties of glass, 45 

'D^rpes classification of glasses, 47 

Tin oxide 80 

Titanium oxide in glass sands, 54 

Tondeur rod lehr, 127 

Transparency of glass, tiS 

Tridymite, 41 

Tscheuschner's formula for normal glass, 25 

method of purifying yellow sands, <(1 

Tuscarora sandstone as source of glass sand, 262 


Uranium oxide , N! 


Venango County, Pottaville glass sand deposits in, 251! 

Venango Sand and Stone Co. , 254 

Violet colored glass, 84 


Warren County, Pottsville glass sand deiK>sit8 in, 255 

Warren SUica Co 255 

Washing device for sand, 62 

glass sand, 56 

Water in glass sand , 53 

Westmoreland County, PottsviUe glass sand deposits in, 258 

White SiUca Sand Co.. 244 

Window or sheet glass, 136 

glass, analyses of, 22 

glass batches, 90 


Yellow colored glass, 84 

Yough Sand and Stone Co 246 


Zinc oxide, 77 

Zoppi, A. S., 20 






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