Full text of "A Memoir on British Resources of Sands and Rocks Used in Glass Making"

See other formats

Published at the Instruction of the Ministry of Munitions of War 
by the Imperial College of Science and Technology. 



A MEMOIR ..^-""' 



ON 

BRITISH RESOURCES 

OF 

SANDS AND ROCKS USED IN GLASS-MAKING, 

, WITH 

NOTES ON CERTAIN CRUSHED ROCKS AND 
REFRACTORY MATERIALS. 



BY 



P. G. H. BOSWELL, D.Sc., 

George Herdman Professor of Geology in the University of Liverpool, 

formerly of the Imperial College of Science and Technology, London, S.W. 7, 

Scientific Adviser (Geological) to the Department of Optical Munitions 

and Glassware Supply, Ministry of Munitions of War. 



WITH, CHEMICAL ANALYSES BY 
H. F. BEARWOOD, M.Sc., Ph.D., and A. A. ELDBJD&E, B.Sc., P.I.C. 



SECOND EDITION COMPLETE IN ONE VOLUME. 



LONDON : 

LONGMANS, GREEN AND CO., 
39 PATERNOSTER ROW, LONDON, 

AVENUE & 3OTH STREET, NEW YOBK, 
BOMBAY, CALCUTTA, AND MADBA8. 
19l8. 



1179 



First edition, Original Memoir December Wlfi. 

Supplementary Memoir November 1917. 

Second edition, complete in one Volume May HHR. 



PRTN'l'KD BY TATtOIt AND FRANCIS, 
nwn T.TON rounr, FLEET STRHBT. 



PREFACE TO ORIGINAL MEMOIR. 



study of the sands employed' i in the manufacture of 
glass has revealed the fact that the veiy exceptional qualities 
displayed by the best of them are not merely those due to chemical 
composition, but are the outcome of their exact mineralogical 
nature, and .even of the size and shape of their constituent grains. 

In nearly all kinds of glass there are certain permissible irre- 
gularities in both . form and composition of the raw materials 
which, allow the employment of. a larger range than had hitherto 
been suspected. A search in localities where Glass-Sand has been 
worked in the past, and at other " likely " places, has shown that 
large supplies are available, and has given, indications of directions 
in which further search might be profitably undertaken. The 
search cannot be regarded as quite exhaustive indeed, it is still 
being prosecuted with vigour, but it has been thought best not 
to delay publication, in order to set free as soon as possible the data 
already collected. ' - 

This work embodies the practical results which flow from a 
series of investigations carried on by Dr. Boswell, with the support 
of the Imperial College from the beginning and of -the Ministry of 
Munitions in its later stages. Large quantities of material have 
been accumulating since 1912, every locality described has been 
personally studied by the Author, and with the exception of 
certain Scottish and Irish sands received by favour o the Assistant 
(for Scotland) to the Director of H.M. Q-eological Survey, and of 
the Department of Agriculture for Ireland only samples collected 
by himself have been subjected to analysis. The chemical analyses 
have been made, by kind permission of Professor Baker, in the 
Chemical Department of the College. They are the work of 
Dr. H. F. Harwood and Mr. A, A. Eldridge, who have devoted 
much thought and care to the methods employed. All the 
mechanical and microscopic analyses and other work have been 



V PREFACE. 

carried on in the laboratories of the Geological Department. 
Much assistance in indexing and in the preparation of photographs 
, has been given by Mr. Or. S. Sweeting. 

Our hearty thanks are tendered to many glass-manufacturers 
and quarry-owners who have given the Author every facility for 
his work, and have freely discussed with him the technique of 
glass-making and the economic factors of the industry. We are 
also indebted for help on the chemical side, both in the discussion 
of results and in the indication of promising lines of enquiry, 
to Professor Herbert Jackson, of King's College, London, and 
to Dr. Walter Eosenhain, F.E.S., of the National Physical 
Laboratory. 

As the study of sands and related sediments has become a 
matter of pressing national importance, and as this is the first 
work published on British resources of these materials, it has 
been thought well to go a little outside the obvious scope of the 
Memoir in two directions : 

(1) The properties of sands are so varied, and the requirements 

of the different industries so diverse, that the Author 
has entered into some detail both on the best methods 
of investigation and on the most convenient modes of , 
expressing the results thus obtained. 

(2) At the same time, the properties of sands suitable for 

glass-making-are in some cases identical with or allied 

^ to those useful for refractory purposes, such as steel- 

moulding, fettling of furnaces, and the making of silica 
bricks. Reference has been made in passing to proper- 
ties of this' nature, and the applicability of the same 
modes of enquiry has been indicated. 

It should be stated, however, that the sands actually described 
in Chapter VI. are only a very small fraction of the total number 
examined and analysed. Hosts of others have been "turned 
down," either because they were wholly unsuitable or on account 
of the possession of properties with which the manufacturer has 
not so far been able to deal. As the chemistry of glass-making 
advances it is probable that some of these disabilities may dis- . 
appear indeed, some of them are all but overcome and then the 
large amount of apparently unproductive information obtained and 
filed by Dr. Boswell will mid its use. 

W. W. WATTS, 

Imperial College of Science and Technology. 
November 1916. 



PREFACE TO THE SUPPLEMENTARY 
MEMOIR. 



THE reception given "by those interested in glass, whether as 
manufacturers or investigators, to the Author's "Memoir oft 
British Resources of Sands suitable for Glass-making," published 
by the Imperial College at the instance of the Ministry of 
Munitions of War, renders it desirable that the information 
accumulated up to 1916 should be supplemented by that acquired 
since. 

Not only has search for suitable quartzose sands been followed 
up, but collateral enquiries have been carried out, particularly with 
reference to deposits bearing constituents so essential to the Glass 
Industry as potash and alumina. It is believed that the survey of 
British resources of glass-sand is now fairly exhaustive, and the 
Author has again made a point of visiting all the sources of supply 
described. A more complete account of crushed rocks and their 
possibilities is now furnished, together with a description of the 
American glass-sands in more common use, 

The work for the "Memoir" received the active support of the 
Imperial College, the publication being approved and its cost 
guaranteed by the Ministry of Munitions. The supplementary 
work detailed in the present publication has been carried out 
entirely under the auspices and with the support of the Ministry, 
the College setting free as far as possible the services of the Author, 
and finding, as before, all necessary laboratory facilities in the 
Geological Department. 

W. W. WATTS. 

Imperial College of Science arid Technology. 
November 1917. 



AUTHOR'S NOTE. 



As the respective Prefaces to the Original Memoir and Supplement 
indicate, the greater portion of the information included in this 
volume has been the subject-matter of two earlier publications. 
It appeared imperative that such information should be, , put 
forward as it became available. But the appreciation of the earlier 
memoirs by those connected with the industries concerned has 
been such as to result in the exhaustion of the first issue and to 
necessitate a second edition. 

In this volume the original and supplementary publications 
have. been combined. A few portions have been re-written and 
further information appended, including additional analyses. 
Repetition has been avoided as far as possible, but the stress of 
the times and the need for rapid re-issue has prevented as exhaustive 
a scrutiny as might have been desirable. The Author therefore 
begs the reader's indulgence in this respect. 

The Department of Optical Munitions and Glass-ware Supply 
of the Ministry of Munitions of War has, by its energetic and 
prescient measures, done much to place the Glass-making Industry 
of the United Kingdom on a sound basis. The scope of manufacture 
has been enlarged and the quality of the products much improved 
by the co-operation of men of business with men of pure science. 
The linking of scientific with industrial elements, to their mutual 
benefit and for the good of the Country, both under the conditions 
of. actual warfare and of the trade-revival which will follow the 
War, is in no small measure due to the far-seeing policy of the 
Controller of this Department, A. S. Esslemont, Esq., C.B.E., who 
has granted every facility to the Author and freely rendered him 
every possible assistance. 

The Author desires to record his indebtedness, in general to the 
Glass-manufacturers, and in particular to Professor Sir Herbert 
Jackson, K.B.E., F.K.S., for the help which has arisen out of many 
visits and discussions. Thanks are again due to Dr. H. F. Harwood 



AUTHOR S NOTE. Vli 

and Mr. A. A. Eldridge, of the Chemical Department of the Imperial 
College, who have carried out nearly a hundred complete chemical 
analyses and over seventy partial analyses purely for this work. 
Ahout one hundred and seventy mechanical analyses and almost as 
many mineral analyses have also been made by the Author in 
connexion with the investigation. Mr. W. B. Wright, B. A., F. Q-.S., 
of the Q-eological Survey of Ireland, kindly adds a note on some of 
the Irish supplies of felspar, communicated by permission of the 
Director. Assistance has at all times been freely rendered by 
Dr. W. E. S. Turner, M.Sc. and Mr. ,T. H. Davidson, M.Sc., 
of the newly-created Department of Glass Technology in the 
University of Sheffield. Prof. C. G. Cullis, D.Sc., of the Imperial 
College, has kindly read the proofs and offered many useful 
suggestions. The Author is also indebted to Mr. G. S. Sweeting, 
who has devoted much time and trouble to checking proofs, and to 
assisting with the photomicrographs and index. 

At the time of the publication of the original " Memoir " a new 
organization, the Society of Glass Technology, had just been in- 
augurated. The valuable papers in the Journal of the Society 
demonstrate the need which existed for such a Body, and arc- 
indicative of the interest now being taken in scientific and technical 
questions relating to glass-manufacture. The work of Mr. C. J. 
Peddle, M.Sc., Chemist to Messrs. Wood Bros, of Barnslej'-, calls 
for special note from the geological point of view, in that he has 
shown the possibility of using in the Works even second-grade 
British sands for making the best qualities, not excepting even 
the optical varieties, of glass. 

Finally, the Author gladly takes this opportunity of expressing 
his indebtedness to Professor Watts for reading the manuscript and 
proofs, both of this and the first edition. The work has benefited 
greatly by the valuable suggestions which have been the outcome 
of Professor Watts' success in popularizing geology by teaching 
and writing, and in promoting the application of geological science 
to industry. The plan of the original Memoir was also due in 
no small measure to the assistance freely and continually given 
by his one-time teacher of geology. 

March 1918 




TABLE OP CONTENTS. 

Page 
PREFACE TO ORIGINAL MEMOIR (by Professor W. W. WATTS, Sc.D., 

LL.D., E.R.S., F.G.S.) ................................................... iii 

PREFACE TO STJPPLEMBNTABY MEMOIR ....................................... v 

ATTTHOR'S NOTE ...................................................................... vi 

LIST OF ILLUSTRATIONS ........................................................... r 

CHAPTER I. Introductory. Utility of Sands. Grade, etc. Some Uaea 
of Sand& in agriculture, as abrasives, for building purposes, 
for water-filtration, as refractories and moulding-Bands , for 
glass-making ............................................................... 1 

CHAPTER II. The Nature of Sands. How Sands are formed. Com- 
position, of Sands. Coating of Sand-grains. Association with 
organic material. Form of Sand-grains. Size of grains ......... 8 

CHAPTBB HI. Methods of Study of Sands. Chemical Composition. 
Mineral Composition. Mechanical Composition screening, 
elutriation, graphical expression of results .......................... 14 

CHAPTER IV. Glass-Manufacture. Literature on Glass-Sands. Raw 
materials importance of sand. Colour, eto. of glass. The 
process of glass-making ................................................... 33 

CHAPTER V. The Requirements of a Good Glass-Band. Characters of 
J?ontainebleau Sand general characters, ohemioal composition, 
mineral composition, mechanical composition, shape of grains, 
economics. Requirements of Glass-Sands. Chemical, mineral, 
and mechanical analyses. Angularity of Glass-Sands. The 
Ideal Glass-Sand .............................. : ............................. 39 

CHAPTER VI. . British Sands etc. Suitable for Glass-making. A. Purely 
Siliceous Deposits, (a) Sands Aylesbury, Fairlight (Hast- 
ings), Bnlverhyth, Ashurstwood, Lynn, Leighton Buzzard, 
Godstone, Eeigate, Aylesf ord, HolHngbourne & Bearsted, 
Lancashire, Huttons Ambo, Burythorpe, South Cave, Denford, 
Tfl.rl-mn.rt.nTi, Longdown, Fordingbridge, Isle of Wight, Charlton, 
Worksop, Alderley Edge. Dune-sands and shore-sands ...... 49 

CHAPTER Vll. A. Purely Siliceous Deposits (continued). (6) Crushed 
! rooks, treatment. " Sand" from Muokish Mountain, Guiseley, 

\.;, Mold, Spital, Caldwell, Kilwinning, Levenseat, Bally- 

I castle, Cookstown, Coolkeeragh, Port-a-oloy, Stiperstones, 

Appin, Anglesey, Achill I. (Westport Silica), Tinahely, eto... 79 



Sections marked thus deal with sands and rooks which are also of value 
for. refractory purposes. 



I , 



TA.BLE OP CONTENTS. ix 

Page- 

OHAPTEB Yin. ^British Resources of Glaaa-Sands, etc.' (continued). 
B. Deposits containing Alumina and Silica, (a) Sands, clays, 
etc. : kaolin from Devon and Cornwall, from Anglesey ; sands 
from South Devon, Nprth Devon, Cornwall, Derbyshire, Staf- 
fordshire, North Wales 98. 

CHAPTBB IX. British Resources of Rocks used, in Qlasa-makvng (Felspars, 
etc.). (b) Siliceous rocks bearing Alumina and Potash. Potash- 
felspars from Cornwall, Scotland, Ireland ; Meldon rook 
(Devon) ; potash-bearing sands 106- 

CHAPTBB X. Special Treatment of Sands and Rocks. Colour of Glass- 
Sands. Washing, drying, screening, burning. Chemical methods 
of treatment. Magnetic methods. Grinding. Crushing strengths. 119 1 

CHAPTBB XI. Foreign Glass-Sands : European : Lippe, Fontainbleau, 
Belgian, Dutch. American : Ottawa Silica Company, Ottawa, 
111. ; Wedron Silica Company, Ottawa, HI. ; Berkshire Glase- 
Sand Company, Cheshire, Mass. ; Berkeley Glass-Sand Com- 
pany, Berkeley Springs, W. Va. ; Juniata White Sand Company, 
Baltimore, ltd. ; Tavern Rock Sand Company, St. Louis 130- 

OHAPTBB XIE. Location of British Supplies of Glass-Saiids \ General 
Geological considerations : Location in England, Scotland, 
Ireland. Distribution of the Glass-making Industry in the 
British Isles 14O 

CHAPTEB XIII. Economic Coimiderat'ionti. Cost of Foreign Sands. 
Economic Factors in working Glass-Sands : workability, treat- 
ment, transport. Statistics. General Remarks 147" 

TABLE I. British Glass-Sands : Iron-Content 154 

TABLE II. Chemical Analyses of British Glass-Sands 155 

TABLE HE. Sundry Chemical Analyses of Alumina- and Potash-bearing 

Rooks, etc 158. 

TABLE IV. Chemical Analyses of Felspar-bearing rocks (Pegmatites) ... 160 

TABLE V. Mechanical Analyses of British Glass-Sands 161 

TABLE VI. Chemical Analyses of European Glass-Sands 166 

TABLE VII. Mechanical Analyses of European Glass-Sands 167 

TABLE VIII. Analyses of Danish Glass-Sands , 16S 

TABLE IX. A. Analyses of American Glass-Sands 16> 

TABLE IX. B. Additional Chemical Analyses of American Glass-Sands . 169- 

TABLE IX. C. Additional Mechanical Analyses of American Glass- 
Sands 170 

INDEX 171 




b 




. CHAPTER I. 

INTEODUCTORY-: USES OF SAITDS.. 

OF the many mineral resources of Britain none are more abundant 
or more varied in quality and use than sands. Their utility, in 
the national economy of this country at least, has never "been tully 
appreciated. Yet the agriculturist, the builder, the glass-maker, 
the metal-founder, and even the housewife, all turn in their need 
to the natural sand-resources of the country. 

To the man in the street to-day the differences between one sand 
and another are neither striking nor important. This attitude has, 
of course, not been shared by those who are concerned with the use 
of sands in industry, hut it is noteworthy that little or no systematic 
investigation of the special properties of British sands of commercial 
value has hitherto been attempted. 

In many industries the best sand available for the purpose has 
been found by a lengthy process of trial and error, but the reason* 
for its suitability or the reverse have rarely been systematically 
looked into. The inevitable result is that when material of value 
for some specific purpose is no longer available serious delay and 
inconvenience are caused. Especially has this been the case in 
glass-manufacture and in the casting of particular steels, for which 
the most suitable -materials in use up to the present were said to be 
certain foreign sands with properties peculiar to themselves. The 
restriction or stoppage of such imported supplies in war-time, owing 
to shortage of ships and labour, has set on foot enquiries as ta. 
Avhether suitable sands occur in Britain, and, if so, whether they can 
be profitably worked. 

Such an enquiry necessitates not only a thorough knowledge of 
the sands themselves, their mode of occurrence and properties, but 
an investigation into the materials previously in use in each 
industry, and an attempt to ascertain the reasons for their special 
suitability. Why, for example, should one moulding-sand " burn 
on " to the steel poured into a mould and another yield a clean 
smooth casting ; or one sand produce a clear, sparkling, white 
glass, fit for table-ware or for optical instruments, and another 
only a poor green bottle-glass ? 

All sands consist, in the main, of silica in the form of broken 
grains of crystalline quartz associated with various forms and 
proportions of impurities, partly impregnating or coating the 
quartz, and partly in the form of grains or dust of other ingre- 
dients. When sand is used as a source of silica, as in glass-making, 
the most obvious requirement is that it should be as pure as 

B 



USES OF SAJfDS. 



possible and especially free from ingredients which would diminif 
the utility or beauty of the finished product. For other purpose 
however, the " impurities " themselves may give the sand its speci 
value. In certain industries the hardness and shape of the grai: 
are more essential than the composition, and the difference betwei 
" angular " and " rounded " grains becomes an important matte 
Again, the size of the individual grains, and more particular 
the relative proportions of material of different sizes in a sarn.pl 
has sometimes a bearing on the use of sand : this is spoken oi ; 
the " grading " or " grade " of the sand. 

In a material xised in such large quantities as sand, suppli 
must be cheap. This means that the sand must be abundar 
loose, or at least easily disintegrated, and cheaply worked; th 
seams or beds must run very evenly in nature and compositio 
and must be cleanly marked off from other seams or material 
above all, that the market must be easily accessible and carria) 
inexpensive and convenient. 

The term "sand" to the geologist connotes a limited range 
chemical and mineral composition, and a definite grade. Theater 
is generally extended to include other minerals than quartz, and 
used in commerce for material of varying grades irrespective 
composition or angularity. It is also applied to consolidati 
sandstones and even to hard siliceous rocks which have be< 
crushed for commercial purposes. In this Memoir the most e, 
tended commercial application of the term will be taken. 

Some Uses of Sands. 

Before passing on to discuss the special properties which it 
desirable for gkss-sands to possess, it will be well to consid 
briefly how desiderata vary in different industries and applicatior 

Sands bearing minerals of the rare earths such as monazit 
xenotime, thorianite, zircon, etc., are worked for the eleinen 
yttrium, zirconium, cerium, thorium, lanthanum, and others, wliw 
are used in the manufacture of incandescent mantles and filamen 
and _ for refractory paints. Those bearing gems, gold, platirmi 
cassiterite, and wolfram are similarly worked for the preckr 
materials they contain. 

Shore-sands, and others auch as the East Anglian " Crags," ri< 
in shell-fragments, form an admirable dressing for the land < 
account of the lime that they yield ; this ingredient promot 
drainage by^ flocculating the clay of the soil, and helps the pla: 
by neutralizing the organic acids naturally produced. Tho val- 
of such shell-sands is enhanced when they occur near to agj 
cultural country and lime has to be imported from a distanc 
It is desirable that all coastal deposits should be investigated . 
ihis connexion. Even if the sands are not calcareous they rend 
heavy clay soils lighter and more open, breaking them up by t 
admixture of coarser grade material, and making the land wannt 
more permeable to air, gases, and water, more easily drained, a: 



ABEA.S1VES, ETC. O 

more amenable to working. Here grade, as well as composition, 
is an important factor. 

The " Greensands," so-called because they are coloured by the 
mineral glauconite which they contain in quantity, have long been 
used as fertilizers. The deposits of economic importance in the 
United Kingdom are of Cretaceous and Eocene age. Glauconite 
is a silicate of iron, aluminium, and potassium ; it decomposes 
much more readily than other potash-bearing silicates such as the 
felspars, orthoclase and microcliue, and thus liberates the valuable 
plant-food, potash. Some greensands are of additional value on 
account of their carrying calcium phosphate, an ingredient also of 
importance in agriculture. Glauconitic sands have also been used 
for softening water. 

The use of sand for abrasive purposes depends on the hardness 
and toughness of its constituents, and on the " sharpness " of its 
grains. Quartz is not only hard, but, as it has no cleavage, it 
breaks irregularly and does not easily comminute under wear. 
It is employed for grinding marble and other stone, plate-glass, 
and metal. It is also used for arming stone-saws, and in the 
.sand-blast applied to glass-cutting and etching, the cleaning of 
castings, and innumerable other industrial processes. In this work 
it soon loses its " sharpness " and requires frequent renewal. In 
the old days the housewife used a cheap, fine, sharp sand for 
scouring purposes, now she buys scouring-soap consisting largely 
of similar tine angular sand bound together with clay, soap, and 
gum *. " Silver-sand " is a term used for a fairly pure fine white 
sand, used mainly for scouring and for lightening soil. Samples 
sold by hardware dealers in London appear, from their mineral 
composition, to come from the Lower Greensand. 

Large quantities of sand are now consumed in the soap-induslry 
for the making of sodium silicate, which is a constituent of some 
of the commoner soaps. Not only have pure quartzites and vein- 
.quart/ been crushed to yield " sands " for abrasive and other soaps, 
but also the relatively impure Glacial sands of Lancashire have 
been pressed into service on account of their proximity to the 
seat of the manufacture. Sodium silicate (" water-glass ") is also 
manufactured for preservative purposes. 

In the manufacture of the artificial abrasive, carborundum 
(silicon carbide), sand and coke are heated together in an electric 
furnace. Carborundum is also used in refractory bricks, as a 
.source of silicon in steel-making, and for certain chemical purposes 
where its reducing properties are of great value. 

Closely allied to abrasives are friction-sands such as those used 
to increase the grip of wheels on metal rails. These sands must 
be not only hard, tough, and angular, but also dry and of even 
:grade so as to slip freely down the feeding-funnel. Similar sands, 
which are better if not angular, are used in hour-glasses and 

* By on order of the German Government in Aug. 1916, the use of sand 
instead of soap for scouring purposes was made compulsory. 



4 USES OJ? SANDS. 

egg-timers. A well-known geologist, when faced with tl^e enquiry as 
to the geological age and characters possessed by these sands, gravely 
avoided the issue by pointing out that it was not the custom of 
geologists to measure time with hour-glasses ! 

The practice of sanding floors has almost died out, but the use 
of sands for road surfaces and for making road materials is- 
increasing rapidly. Angular sands, free from clay, are utilized in 
the asphalt industry, the mixture of sand and pitch being of 
considerable value for road-dressing. The sands utilized are, as- 
far as possible, of local origin ; Lower Greensands from Surrey 
and Bedfordshire, and Corallian sand from Oxfordshire, have been 
exploited for this purpose. 

Considerable quantities of sand are worked for building-purposes. 
Most sands are suitable for mixing with lime and water to make 
mortar, and usually each district is able to satisfy its own demands. 
Shore-sands are, however, avoided on account of the tendency of 
mortar made from them to " sweat " owing to the thin films of 
deliquescent sea-salts having been left as a' coating on the grains 
when the sea-water evaporates. These salts are brought to the 
surface by percolating water, and left on evaporation. A similar 
effect is observed in the complete breaking up of Chalk fossils 
collected from spray -beaten cliffs, unless they have been well soaked 
in fresh water before storing. Building-sands should be fairly 
angular and not too fine, in order that their grip on the calcareous 
matrix may be strong, the mortar becoming . truly a miniature 
concrete. Sands used with Portland cement ought not to be 
rounded in grain and should previously be washed to ensure 
cleanness of surface. 

The clays worked for brick-making are often stiff deposits of 
almost pure cla}'. As such they can only be used for making flat 
tiles and pipes where great strength and adhesion are required. To 
reduce shrinkage and cracking during the drying and firing of 
bricks, sand is added to the clay and thoroughly mixed with it. A 
porous brick of g'ood shape and soundness results. Here, again, the 
grade-composition is a leading factor. Manj r of the so-called clays- 
in the geological formations of Britain are not true clays, but 
contain already a variable admixture 'of sand and are thus really 
loams. The G-lacial brick-earths, the Keuper " Marls," and the- 
London "Clay" are deposits of this character largely employed 
,for brick-making. 

Parting-sands, which are usually dry, sharp, fine, quartzose- 
sands, are used in metal-casting and in the manufacture of bricks 
and pottery. In the case of brick- and tile-making, the sand used 
to "dust " the mould exercises considerable influence on the texture 
and colour (due usually to oxides of iron) of the surface of the- 
article. The ability to withstand weathering and the aesthetic 
value thus depend in part upon the sand. The use of sand, as a 
substitute for flint when the latter is not procurable in the 
making of glasce, has not found much favour in the Potteries. 
Sand is used for repairing and lining kilns or " ovens " and for 



REFBACTOEY S-AJTDS. 5 

dusting tlie floors. In metal-casting, "burnt" moulding-sand 
from near the surface of previously-made castings is frequently 
and successfully used as a parting-sand. 

In connexion with water-supply, sands are of considerable im- 
portance for purposes of filtration. In order that there may be a 
large proportion of interspace between the grains, the sand should 
be fairly coarse and its grains preferably rounded, with as large as 
possible a percentage of grains belonging to one grade. Thus the 
sand should be free from clay, and of course from organic matter, 
while the absence of lime is an additional advantage. 

Before the introduction of blotting-paper sand was of service as 
an^absorbent f or 'superfluous writing-ink. It is said to be similarly 
utilized in modern industrial practice as an absorbent for explosive's 
of the mtro-glycerine type, in substitution for such natural siliceous 
earths as diatomite and kieselguhr. 

The most important commercial uses of sand, namely, those 
connected with the property of refractoriness to high temperatures, 
have been left until the last. Silica, of which quartz is the com- 
monest crystalline form (though other allotropic modifications such 
as tridyrnite and cristobalite exist), has to be raised to a very high 
temperature (1650 Centigrade) before effective fusion takes place. 
Quart/ose sands and sandstones bearing a high percentage of silica 
and no fluxes such as alkalies or alkaline earths are therefore in 
great demand for the floors, sides, and roofs of kilns and furnaces, 
and for the bottoms of soaking-pits. Sands of corresponding 
composition are also required for fettling furnaces (that is, re- 
coating with silica the baths which hold the molten metal), making 
crucibles and fire-bricks, and other similar purposes. 

"Silica-bricks," used so largely for furnace-work, gas-ovens, and 
similar purposes where very high temperatures must be successfully 
withstood, are made from refractory sands. No lime or other 
alkaline earths, no alkalies, and very little, if any iron, should be 
present. Highly quartzose sands are therefore required, and a 
great advantage accrues if such sands possess a " bond " which is 
itself refractory. As examples may be quoted the kaolin-bearing 
whitish sands of Devon and Cornwall, associated with kaolinized 
granite, and the similar deposits of the Mountain Limestone district 
of Derbyshire and Staffordshire. 

Included in the subject of refractories comes the wide and 
difficult problem of moulding- sands. These vaiy according to the 
metal which is being cast, the shape of the mould, and their position 
with respect to the metal. Thus there are facing- and core-sands 
in addition to ordinary moulding-sand, and the range in composi- 
tion is from true sands almost entirely composed of quartz to loams 
containing no small proportion of clayey bond. The problem of 
moulding-sands is too large and controversial to be entered tipon 
here, and demands a memoir to itself, but a few points may be 

Sections marked thus deal with sands and rocks which are also of value 
for refractory purposes. 




CHAPTER II. 

THE NATURE OP SANDS. 

Formation of Sands. Sands and similar deposits are the 
result of the gradual breaking down of rocks. The sun's heat, 
frost, rain, and gravity are among the geological agencies which 
are chiefly engaged in this work of disintegration and attrition. 
Fragments of rock, in their continual movement to lower levels, 
are reduced in size by wear and tear, and broken up into their 
constituent mineral grains. Chemical, as well as mechanical, action 
assists in this work. The more easily decomposable minerals rot 
away, and the more obstinate are loosened from one another. In 
the decay of minerals the more soluble salts are carried off in 
solution, while the less soluble yield fine clayey or micaceous 
material which may be carried in suspension for long distances. 

The disintegration of rocks thus results in the production of 
simple individual mineral grains varying considerably in size. 
This material is carried downwards towards the sea, and collected 
at lower levels. In transit it is winnowed by wind and washed by 
water. Most sands and related sediments are either deposited in 
water or have been washed down and assorted by water at some 
time in their history. The sorting is controlled by the S'VM and 
weight of the grains, coarser grains and denser minerals being 
.dropped down near to the source of supply. This sorting is never 
perfect, and it is not usual to find in geological strata a deposit 
made up entirely of material of one size. Nor even do we find, 
with very rare exceptions, that one grade sand, silt, or- clay 
makes up the whole of a single bed. The manner of transport 
and deposition leads in any one deposit to a mixture of grades 
which may be valuable or inimical from a commercial standpoint. 1 

A tendency generally exists for the collection in basins of 
deposit of material which has been brought from many different 
sources. Working against this tendency towards the production of 
rocks of mixed grades we have the selective transport and depo- 
sition due to currents of air and water. Heavier and larger fragments 
are dropped first, finer ones are canned farther, and the finest 
frequently travel long distances before the velocity of the stream 
is so far reduced that they come to rest. A fairly complete.- 
natural grouping therefore takes place, gravel, sand, silt, and mud 
boing found at successively greater distances from their place of 
origin. But this grading by water or air is not a perfect ono ; 
the manner of transport varies accordingly as the small particles 

Sections marked thus deal with sands and rooks which are also of valuo 
for refractory purposes. 



iSi LIBRARY ) 

AND COMPOSITION jGff", SA1TDS. 9 /S 




are held in suspension, rolled along the boi 
by leaps (saltation), and the final deposition^ 
variation of direction and velocity of the currents^ 1 
upon the precipitating power of dissolved salts. 

Sudden arrest of material near to its source, especially where 
it has been brought down by torrent-action, results in deposits 
consisting of about equal proportions of coarse and fine grades ; 
they may be termed " non-graded " (see Fig. 8 and page 32). Such 
a case is exemplified by many of the Cretaceous and Tertiary deposits 
around the Dartmoor and Cornish granite-masses. Torrential 
streams of water poured down the slopes and ravines in past ages, 
rolling pebbles and boulders of granite and limestone, fully charged 
with grains of quartz, felspar, tourmaline, etc., and milky-white 
with china-clay from the decomposed felspar of the granite. The 
sudden checking of their velocity when they reached the still waters 
of the lakes, the larger sluggish rivers, or the lower ground, caused 
the bulk of the transported material to be thrown down higgledy- 
piggledy, all grades mixed, frequently as an alluvial fan. 

On the other hand, the continual sorting of sediments along the 
shore by the action of waves and winds has resulted in the elimination 
from shore- and dune-sands of both very coarse and fine material. 
The clay and silt particles are carried far away by wind and water, 
and the coarse sand and gravel left alone; thus the percentage 
of medium-sized sand rises very high, and the deposit is almost 
perfectly graded. 

Composition of Sands. Usually each grain of sand is an indi- 
vidual mineral fragment contributed by the parent rocks which 
have undergone denudation. While sands are frequently made up 
of a large variety of different minerals, quartz and, to a less extent, 
felspar usually constitute more than nine-tenths of their bulk. 
The chemical composition of the constituent minerals, their prone- 
ness to decay, and the compounds resulting from their partial 
or complete decomposition, are all important factors when the 
commercial use of the sand is under consideration. 

While the grading of sands and the sorting of minerals according 
to density are never perfect, a strong tendency exists towards 
simplification, which is helped by the proneness to decay of the 
less stable minerals. J3y repeated geological action, sorting again 
and again, very pure and well-graded sands come to be formed, 
and it is noteworthy that ah 1 the best glass-sands occur in the later 
geological formations. On the other hand, the ancient Ordovician 
and Silurian "sands" are usually ill-sorted and very variable in 
composition. 

As a rule, sands contain only a small proportion, of the minerals 
known as the heavy minerals, which possess a density greater 
than 2'8. These, like quartz, have proved themselves sufficiently 
stable to withstand decomposition, and their presence is often a 
useful indication of the source of the sandy material. Most of 
the common rock-forming minerals occur in sediments in more or 



10 THE NATTTKE OP SANDS. 

less relative abundance. In ordinary sands the proportion of 
heavy minerals varies from O02 per cent., or even less, to 4 or 5 per 
cent, by weight (the latter quantity in sands of fine or superfine 
grade only). 

The minerals composing sands may be divided into two groups : 
the allothigenous or detrital minerals, derived from older rocks, 
and the authigenous minerals, which were formed at the time 
the sands were deposited or at some later date. "We are mainly 
concerned with the allothigenous minerals. Some of the heavy 
detritttl minerals are fixed chemical compounds, others are molecular 
mixtures which vary somewhat in their composition, the colour and 
optical properties changing- sympathetically with the chemical 
constitution. In the latter group are the pyroxenes (augite, etc.), 
amphiboles (hornblende, etc.), olivines, epidotes, etc. 

The chief heavy minerals occurring in sands are the following: 

OXIDES > Anataae, brookite, mtile (TiO a ). 

Oassiterite (SnOs) ; corundum (Al a O a ) ; hematite (Fe a O n ) ; limonite 
(2Fe.,O., . SH.,0) ; magnetite (Fe-,0,); spinel (oxides of Fe, Cr, Mg r 
Al, eto.'); titanoferrite or ilmenite (FeTiO ;1 ); 



SILICATES : AndaluRite (silicate of Al) ; augite (metasih'oate of Al, Fe r 
Mg, Ca, Na, eto.) ; biotito (silicate of Al, H, K, Fe, Mg) ; enstatite 
(MgSiO a ) ; epidote (hydrated silicate of Ca, Al, Fe) ; garnet (silicate- 
of Mg, Ca, Mn, and Fo, Or, Al) ; glauoonite (ailioa^e of K, Al, Fe) ; 
hornblende (metasilicate of, Al, Fa, Mg, Ca, Na, etc.) ; hypersthene 
(MgFe)SiO;, ; kyonite (silioate of Al) ; musoovite (silioate of H, K, 
Al) ; olivino (orthosilioate of Mg, Fe) j sillimanite (silioate of Al) ; 
sphene (CaTiSiOJ ; staurolite (silioate of Fe, Mg, Al) ; topaz (fluo- 
silioate of Al) ; tourmaline (boro-ailicate of Al) ; zircon (ZrSiOJ. 

Oilier compounds : Apatite (caloium phosphate with calcium, fluoride or 
chloride) ; caltrite (CaGO.,) ; monazite (phosphate of Co, La, eto.) - t 
pyrite (FeS.J ; pyrrhotite (approximately FeS). 

Where older sediments have been broken down to make new 
rocks, only the most obstinate detrital minerals, such as iron ores- 
(including particularly ihnenite), mtile, zircon, tourmaline and 
others, survive, and the proportion by weight is low. When 
crystalline rocks of igneous and metamorphic origin are subjected 
to denudation, they yield a rich and highly varied assemblage of 
minerals. It is noteworthy that most of the heavy minerals 
occurring in sediments are of raetnmorphic origin ; as examples 
may be quoted, spinels, garnets, rutile, tourmaline, staurolite, 
andalusite, sillimanite, sphene, epidote, muscovite, biotite, chlorite, 
kyanite, and amphiboles (including common hornblende, glauoo- 
phane, actinolite, etc.). Igneous rocks appear to provide an 
assemblage of minerals more liable to decomposition. However, 
those derived from an area of pneumatolysis are fairly stable, and 
include garnets, cassiterite, tourmaline, topaz, andalusite, etc. 
Minerals derived from other igneous rocks include zircon, rutile, 
anatase, apatite, brookite, white and dark micas, hornblende, and, 
less commonly, augite, together with a few others. 

The mineral constitution of a sediment varies not only with the- 



COATING Ol- 1 SAJTU-aKAUra. 11 



parent rocks laid under contribution, but with its distance from 
the source of origin, the grade, and the conditions of deposition. 
Unless local concentration is produced by wind- or stream-action, 
or by the oscillatory effect of currents, the proportion by weight 
of the heavy crop will tend to decrease the farther we go afield, and 
the variety will be reduced as minerals prone to decay are eliminated. 
The exact connexion between mineral composition and grade is 
not yet thoroughly understood; it is undoubtedly a close one. 
During the process of deposition, other minerals may be formed 
through organic agency, among them being glauconite, calcium 
phosphate, Hmonite. 'secondary silica, etc. 

Finally, we have those minerals (authigenous) which develop 
subsequently in sedimentary deposits as a result of alteration of 
other minemls ; a few such are iron oxides, secondary silica, 
leucoxene, anatase, chlorite, etc. 

If the heavy minerals are present in quantity in a sand they 
affect its chemical constitution very considerably. Alumina might 
be expected to be abundant in a heavy residue, and it is note- 
worthy that lime is usually low, the lime-bearing minerals, Avith 
the exception of some hornblende, pyroxene, epidote, etc., tending 
to decompose. In sands subjected repeatedly to the action of 
geological agencies, the latter group of silicates first disappears, 
then the ferro-magnesian minerals, and, finally, the aluminous 
silicates, when certain iron ores, zircon, rutile, and tourmaline only 
survive. 

Coating of Sand-grains. On the principle that, chemically, 
dirt is only "matter in the wrong place," the detrital minerals 
of a sand may be regarded as impurities when we desire to find 
a sand pure enough for a particular purpose such as glass-making. 
More important, however, are the impurities resulting from decom- 
position of these minerals and those introduced either during 
deposition of the bed or subsequently by the action of percolating 
water. An example of such an impurity is the iron staining in 
tints of red, brown, and yellow, so widely met with in rocks. 
Oxide of iron (as hematite, Fe.,0.,, or limouite, 2Fe 2 O.,.3H a O), 
"Nature's colour-box," acts as a coating to the mineral grains 
and at times cements them together into a compact rock. Other 
minerals, such as silica itself, clay, fluorspar, barytes, calcite, 
dolomite, phosphates, etc., also play a cementing rdle. Certain 
unconsolidated sands, while apparent!}' fairly pure and clean, have 
a fine dust-like coating of clay or calcareous material deposited 
upon the grains. 

Association with Organic material. Sometimes organic 
material such as plant-remains has the effect, either bj r acting as 
a reducing agent or ~by the production of humic acids, of clearing 
a sandy deposit of impurities or of rendering them more easily 
soluble in percolating water. Some of the purest quartz-sands 
known to us, remarkable on account of the freedom or the grains 



12 



THE MATU11E OP SANDS. 



from the slightest ferruginous coating, are associated with carbon- 
aceous material ' (see Chapter VI.). The famous glass-sands of 
Fontainebleau in France, Lippe in Saxony, Hohenbocka in Prussia, 
and Aylesbury in England, are apposite examples. The purity of 
Coal-Measure Sandstones is interesting in this connexion, and the 
bleaching, to the depth of a few feet, of the yellow and red sands 
on our heath-lands is a well-known phenomenon. This question is 
considered in more detail on page 140. 

Form of Sand -grains. During their progress from the dis- 
integrated parent-rock to their final resting-place, mineral grains 
suffer continual abrasion. If the habit is needle-like, or the 
cleavage good, there is a general tendency for rapid fragmentation 
and disappearance. Brittleness and softness help the speedy reduc- 
tion in size of grains, but when a soft mineral, such as mica, has a 
single perfect cleavage, it may be buoyed up and travel a long way. 

The continual battering to which grains carried by water are 
subjected results in the wearing down of the sharp edges and 
angles, and the sands become suhangular. Prolonged rolling 
action produced by currents up and down a shore-line, or repeated 
action on the same grains through successive geological cycles, may 
gradually round even quartz sand. Pot-hole water-action in a con- 
fined space (e. g. under glacier-ice) produces sometimes a beautifully 
rounded sand. Much more rapidly, however, are sands rounded 
by the action of wind, when the grains are continually rubbed 
against one another, or meet other obstacles, with no water present 
to act as a cushion or a lubricant to reduce friction. Many 
desert-sands consist of grains which have been rounded in this way, 
but just as the want of rounding does not imply the absence of 
desert-conditions, so also its presence may not necessarily he due 
to wind-action. Sand-dunes, so common around the shores of the 
British Isles, consist of shore- sands which have been blown up into 
mounds by wind-action, hut that action has usually not been 
sufficiently prolonged to change the angular or subangular shape of 
the grains. 

Size of Grains. The sorting effect of water and air upon 
sediments has been briefly referred to early in this chapter. It is 
necessary to consider systematically the sixes of the grains con- 
stituting sediments and their relative proportions by weight. At 
the outset it should be repeated that the term " sand " has different 
significations to the layman and to the geologist. In the above 
remarks '' sand " has been used in its wider commercial sense, and 
therefore includes related loose deposits bearing some amount of 
clay and other material in their composition. In its stricter geo- 
logical use sand is a ' grade " term, that is, one depending 
only upon the size of the constituent grains. Although most 
sands happen to be made up largely of one mineral quart/, the 
real criterion upon which the geologist bases his definition is the 
high percentage of grains with average diameter between 1 mm. 



SIZE OF GRAINS. 13 

and O'l mm. (about 0'04 and 0'004 of an incli). Very coarse 
sands may have grains up to 2 mm. diameter, and very fine ones 
down to O05 mm., but these, are extreme limits. Pebbles of 
diameter over 2 mm. fall into the grade known geologically as 
" gravel " (not the commercial term of the building-trades, which 
connotes a coarse concrete-making bouldery deposit with a good 
deal of sand and fine clayey "bind"). Particles of diameter less 
than 0'05 mm. constitute "silts." A further limit exists, and 
deposits made up of mineral fragments the diameter of which is 
less than 0-01 mm. (0'0004 in.) are true "clays" or "muds." 
A useful classification of the size-limits or grades is therefore : 

Q. Greater tliau 2 mm. dium. Grnvel (G). 

VCS. 1 mm. and loss than 2 mm. Very coavse sand. --> 
CS. O'o mm. 1 mm. Coarse sand. 
MS. 0-26 mm. 0'6 mm. Medium sand. Sliud - 

FS. 0-1 mm. 0-26 mm. Fiiie sand. J" e ^ e 

r 0'05 mm. O'l mm. Superfine sand or N ... 

\ .,, 1 oilt- 

s.-j coarse silt. J Lgj.^ 

V 0-01 mm. 0'05 mm. Silt. J (a), 

c. Leas than O'Ol mm. Clay or mud grade (c). 

The letters Gr, S, s, c, etc., denoting the various grades are for 
use in this Memoir only as a means of shortening the expression 
of the mechanical analyses quoted in later chapters. Thus, a 
sand from the Eed Crag at Foxhall, Suffolk, consisting of 11'8 per 
cent, by weight of very coarse sand-grade ( > 1 mm. & < 2 mm. 
. diam.), 44'1 per cent, of coarse sand-grade (>0'5& <lmm.), 
41-5 per cent, of medium sand-grade f>0'25 & <0'5), 2'2 per 
cent, of fine sand-grade (>0'1& <0'25), 0'2 per cent, of silt- 
grade (>0-01 & <0-1), and O2 per cent, of clay-grade (<0'01> 
would be represented thus : 

YCS 03 MS FS jj c S 
11-8' 44-1' 41-5' 2-2' 0-2;' ; 2 ; 99-6' 

where S represents the total sand-grade ( >0'1 mm. diameter). 



14 METHODS OF STUDT Of SANDS. 



CHAPTER III. 

METHODS OF STUDY OF SANDS. 

For His proper knowledge of sediments, considering both their 
geological interest and economic value, it is desirable that we 
should be acquainted with the chemical, mineralogical, and 
mechanical compositions of each sample. In the reading of " the 
riddle of the sands," each of these three analyses yields interesting 
.and valuable data, and for glass-sands in particular the chemical and 
mechanical analyses are most important. Although desirable, it 
is not so essential for commercial purposes that we should also be 
.acquainted with the mineral composition ; the knowledge is, never- 
theless, of considerable value in special cases and may give an 
indication of the particular treatment required and of the presence 
of minerals detrimental to the industry, or may enable the user to 
ensure that successive consignments of sand come from the same 
quarry or bed. 

Chemical Analysis. 

Since quartz and felspar usually make up the bulk of a sand; 
and aluminous silicates that of a clay, the silica-percentage gener- 
ally runs fairly high, reaching in very pure sands and sandstones 
9S or 99 per cent. Complete analyses are very desirable, especi- 
ally of moulding " sands," but where only fairly pure sands 
are investigated, as in connexion with glass-making, it is often 
sufficient to estimate silica, iron oxide (as Fe a 3 ), alumina, and 
water. Other elements will rarely be present in quantities larger 
than "a trace." If they should be, however, it is highly desirable 
that even small percentages should be recorded. Their effect in 
the actual making of the glass is not known, but .numerous 
problems and difficulties have arisen in the processes and have not 
jet been explained. Small quantities of foreign substances may 
play a greater part than has hitherto been suspected in determining 
the character of satisfactory or unsatisfactory glass. 

The chemical composition varies according to the amount and 
character of the cementing material upon the individual grains, 
but more according to the variety and relative abundance of 
detrital minerals present. As previously remarked, the heavy 
detrital minerals are mostly oxides and silicates, but borates, 
fluorides, phosphates, chlorides, etc., also occur. The total silica 
estimated in a sand is therefore made up of free silica, that of the 
quartz-grains themselves, together wi^h the combined silica of the 
other minerals. If it is not desired to carry out a complete 
chemical analysis involving fusion with alkaline carbonates, the 
iron-content of the sand may be estimated for glass-purposes after 



MINERAL ANALYSIS. 15 

digesting the sand with hydrofluoric and sulphuric acids in a 
platinum basin, as mentioned below. 

In carrying out cheinical analyses of glass-sands the following 
precautions should be observed. . Silica should be estimated in the; 
usual way, being separated by three evaporations with hydro- 
chloric .acid with intervening filtrations. The purity of the 
weighed silica must in all cases be checked by evaporation with 
pure hydrofluoric acid and a drop of sulphuric acid ; if this pre- 
caution be omitted the results obtained will invariably be slightly 
higher than the true value. 

Iron is best determined by a colorimetric method in a separate 
sample after solution in hydrofluoric and sulphuric acids. As in 
some cases iron-bearing minerals which are only incompletely 
attacked by these acids are present, any insoluble residue, especially 
if dark coloured, should be filtered oft', ignited, and fused with a 
little sodium carbonate or potassium pyrosulphate. The melt is 
dissolved in dilute sulphuric acid and added to the main portion. 
A blank test with the reagents alone should always be made to 
ascertain whether these are free from, traces of iron. 

Titanium may be conveniently estimated colorimetricallj- in the 
portion used for the determination of the iron. Care must, how- 
ever, be taken to ensure the complete expulsion of the hydrofluoric 
acid, as even small amounts of this render the colorimetric estima- 
tion inaccurate. 

No constituents should be estimated by difference, and the 
ordinary commercial chemical analyses of sands (which usually 
give a total of exactly 100 per cent.) are of little value for glass- 
making or refractory purposes. 

Mineral Analysis. 

Apart from the determination of the actual species present, 
the mineral analysis is useful as giving an indication of the 
relative amount of heavy detrital minerals and the quantity of 
such lighter minerals as quartz and felspar. The earliest method 
in use for the purpose of conducting a mineral analysis was that 
of "panning," so well known to the miner. Gentle agitation of 
the sand beneath water, combined with a slight rotary movement 
with a jerking "throw," has the effect of causing the heavier 
minerals to segregate at the bottom. The lighter constituents 
above, making the bulk of the sand, are washed off carefully in 
a gentle water-current. Separation of minerals such as quartz 
from gold or cassiterite (tin ore), each of which differs considerably 
> from it in density, proves very successful, but for geological in- 
vestigation, where it is desired to separate minerals of density a 
little below and a little above 2-8, the method by itself is not 
suitable. To reduce the bulk of the sediment, and to increase 
the relative proportion of heavy constituents in order to obtain a 
larger quantity for qualitative examination, panning is adopted. 
If carried too far, some of the less dense of the heavy minerals 
may be washed away with the lighter. 



16 



METHODS OF STUDr OF SA.NDS. 



Before being analysed inineralogically, a sediment is sifted free 
from larger compound grains, and, if necessary, washed clean from 
clayey matter. The dried sand or silt is then treated with heavy 
liquids to obtain the small crop of minerals the density of which 
is greater than 2-8. The proportion of these is usually so small 
that examination of the untreated sand only revetls occasional 
grains. The densities of quartz and felspar, which make up the 
bulk of sands, vary from 2'54 to 2'76, while those of the more 
interesting detrital minerals mentioned vary from 2'9 to 4 or 
more. Quartz, felspars, and certain other light minerals therefore 
float in a liquid of density 2-8, while the heavy minerals sink. 
The apparatus required for mineral analysis is very simple. An 
ordinary funnel (dropping funnels have been used, but the open 
conical form is perhaps preferable) fitted with a ground-glass tap 
or rubber- tubing and pinch-clip is all that is required (Figs, 1#, 1 i). 



Fig. 1 a. 



Fig. II. 





\l 



Funnels for separating "heavy minerals from sands. 

The most suitable heavy liquids in use are brornoform (density 
about 2-84) and Thoulet's (Sonstadt's) solution (mercury potassium 
iodide in aqueous solution, density from 2*8 to 3 - l, according to 
concentration). The heavy liquid is poured into the funnel and 
the sediment added, the whole being well stirred at intervals to 
permit of the easier settling of the heavy grains. When the 
separation is complete (in practice it is probably never perfectly 
so) , the light grains form a belt at the top of the liquid, there is 
usually an intervening clear portion, and a sediment of heavy 
grains occurs below. The latter portion of the sand is tapped off, 



MIITEBAL ANALYSIS. ' 17 

filtered from heavy liquid, and washed with benzene if bromof orm has 
been employed, or distilled water if use has been made of Thoulet's 
solution. The light crop is similarly dealt with, the Avashings in 
each case being saved and concentrated later over a water-bath or 
by distillation. Heavy liquids are thus used many times over. 

If necessary, the heavy crop may be further separated for diag- 
nostic purposes by magnetic, electromagnetic, electrostatic^ rolling, 
and other methods, and by treatment with heavier liquids, such as 
inethylene iodide (density 3'3) *. 

After some practice, many of the tiny heavy mineral grains may 
be recognized by examination with a high-power hand-lens ( x 15 
or 20 diameters). Eor permanent use under the microscope they 
are mounted in the usual manner in Canada balsam (refractive 
index about 1'58), and examined in transmitted and reflected light. 
Tor rapid temporary examination it is useful to immerse some of 
the residue in such a medium as clove oil (refractive index about 
1-53), but then the mount is not permanent. The minerals are 
-identified by their shape, crystalline form, cleavage, fracture, en- 
closures, alteration, and such optical properties as colour, refractive 
index, pleochroism, birefringence, extinction -angle, interference 
figure (directions-image), twinning, etc. For these mineral 
characters reference must be made to any good book on rock-f orming 
minerals. The size of the different mineral grains is measured by 
means of eyepiece and stage micrometers. 

The heavy detrital minerals usually stand out in relief (owing 
to their higher refractive indices) when examined in balsam or 
clove oil (see Plate II. figs. 2, 3, and 4). It is also useful to- 
examine some of the lighter crop in the same way. Since quartz, 
and felspar have refractive indices very near to that of the medium 
(clove oil or Canada balsam), the grains if fresh and clean have- 
very faint borders in ordinary light (see Plate II. fig. 1). A very 
slight ferruginous coating on the grains is then easily detected. 
Q-rains of a highly pure glass-sand immersed in clove oil almost 
disappear. Felspar is usually turbid with alteration products con- 
sisting of micaceous material or clay (kaolinization) . 

In certain exceptional cases, where the grading has been well 
earned out by natural agencies and a good proportion of heavy 
minerals is present, ordinary sifting will separate, to a remarkable- 
degree, the coarser light minerals and the finer heavy ones which 
required the same strength of wind- or water-current to transport 
them. As an example may be quoted the dune-sand from Bal- 
gownie Links, near Aberdeen. A mechanical analysis of this 
deposit yields : Coarse sand 2 - per cent., medium sand 91-2 per 
.cent., fine sand 3'3 per cent., superfine sand or silt 2'9 per cent., 
dust, etc., 0'6 per cent.; total sand-grade (>0'1 mm. diameter) 
96'5 per cent. The portion of diameter greater than O25 mm. 

* T. Orook, " Tlie Systematic Examination of Loose Detrital Sediments,"' 
Appendix to Hatch & Rastall, ' Sedimentary Books,' London, 1913. Wein- 
sohenk (translated by Clark), " Petrographio Methods," New York, 1912,. 
and other works. 

C 



jg METHODS OF STUDY OF 

(medium and coarse sand) consists of quartz and felspar, while 
that of diameter 0'25 to O'l ram. (fine sand) consists almost 
entirely of heavy detrital mineral grains, epidote, augite, garnets, 
tourmaline, and zircon being conspicuous. 

In very pure sands or sandstones, the heavy crop may be less 
than O'Ol per cent, in weight, but it sometimes increases to 4 or 
5 per cent., as, for example, in some samples of Bagshot Sands, 
Inferior Oolite Sands, and others. Usually it is found that the 
coarser the sand becomes the smaller is the heavy crop yielded ; 
silts and fine sands often cany the highest proportion. Estimation 
of the heavy crop of true clays is very difficult to make, as it has 
not been possible to obtain a good separation in a heavy liquid of 
the very fine material which takes a long time to settle. 

Complete mineral analysis may, as a rule, be earned out within 
an hour, that time serving also for the identification of all the 
important detrital minerals. Mineral analysis is much more rapid 
than chemical analysis, and yields general information as to the 
chemical compounds present and then; relative abundance. A check 
upon the chemical analysis and a knowledge of what elements to 
look for are thus obtained. Chemical, mineral, and mechanical 
analyses may all be in operation at the same time. 

Mechanical Analysis. 

A mechanical analysis of a sediment seeks to record the various 
sizes of the constituent grains, and the relative proportion by weight 
of grains between certain limits of size. These size-limits are 
known as " grades," and a useful classification has been given in 
Chapter II. on page 13. 

The general importance of mechanical analyses in industry is 
only being realized very slowly. Agriculturists have long recognized 
the value of mechanical soil-analysis ; indeed, the methods of work 
were first introduced in this connexion. Mining-engineers subject 
their battery-pulps to such analysis in order to determine the effi- 
ciency of their machinery, and they use various forms of apparatus 
designed to separate pulps into grades*. Water-engineers have 
recognized the importance of the knowledge of relative proportions 
of certain sizes in coarser sands and gravels in the matter of 
water-filtration, and the distribution and movement of underground 
waters f. The significance of the method has been realized to 
some extent in pottery -work. Not yet, however, have glass-manu- 
facturers, metal-founders, brick-makers, and others fully appreciated 
the value and importance to themselves of a knowledge of the. 
mechanical constitution of the clays, silts, loams, and .sands which * 
form their raw materials. ITrequently there has been some realiza- 
tion of the value of the investigation^ but crude methods of sifting 

* H. Stadler, " Grading Analyses by Elutriation," Trams. Inst. Mitring & 
Metall.-rrii. (1912-1913) page 686. 

f C. S. Sliebter, "Motions of Underground Waters." Water-Supply and 
Irrigation Papers, U.S. Gaol. Surrey, No. 67 (1902); King, U.S. G. S. 19th 
.Annual Eeport, 1897-8, page 67. 



MECHANICAL ANALYSIS : SCJtEENINtf. 19 

rare often deemed sufficient. That the old order of things is 
changing is evidenced by the fact that elutriation apparatus has 
been set up in a few works as well as in a few scientific institutions 
in this country. Some managers of glass-works have recognized that 
the grade-analysis of a glass-sand is of as much importance as tne 
chemical composition (provided, of course, that the latter does not 
fall outside certain limits). Otherwise no scientific investigation 
.as to a suitable mechanical composition has been made, experience 
being trusted to as a genei-al rule. Usually only sifting through 
wire-screens has been adopted by sand-merchants or manufacturers 
.and founders. 

(a) Screening. Sifting or screening may be resorted to for 
^coarse sands, but for fine material the procedure is objectionable 
both because of liability to contamination and want of accuracy. 
Moreover, very fine grades cannot be separated by sieves, as the 
.-apertures cannot be made sufficiently small. Prom a scientific 
standpoint the sifting of sediments through wire-screens with 
.square or rectangular mesh does not give accurate results, since 
grains of various diameters up to the length of the diagonal of the 
.aperture pass through. It is the mean and not the major dia- 
meter of the grains which determines what shall pass the screen. 
Sifting, therefore, does not guarantee sizing. Where sifting is 
.adopted, round-holed sieves, with the holes punched out and set in 
60 triangular spacing, should be used. It is even then questionable 
whether sifting much below 0'5 mm. (about 0-02 inch) is entirely 
satisfactory. Smaller holes than 0'5 mm. cannot be punched with- 
out difficulty, and O25 mm. (O'Ol inch about) sieves are therefore 
wire screens *. The latter mesh is the minimum limit of screening 
.adopted by the writer. In these screens and in the smaller " 120 
to the inch," supplied by makers, the apertures are square and 
tend to become clogged by use. Contamination thus occurs, 
-especially if the metal of the screens be iron, which inevitably 
rusts in time. All sieves for scientific work should be made of 
copper or brass. 

Before passing on to a description of the forms of apparatus 
used in elutriation, a note is desirable upon the standardization of 
.grade-measurements. As in other scientific work, the use of the 
metric system units is preferable and simplifies all calculations. 
r The grade-sizes adopted in this Memoir are therefore expressed 
in millimetres, and may be converted to English units if required 
(25'4 mm.. 1 inch). Screens are frequently made according to 
English units, 30, 60, 90, etc., meshes to the inch. In the I.M.M. 
mesh screens (inch-units) the thickness of the wires is equal to 
the diameter of the aperture, hence, for example, a 120-mesh screen 
has apertures about 0'004 inch iii diameter (about O'l mm.). In 
other screens (30, 60, 90 mesh, etc.) this is not the case, the wires 

* Perforated brass or copper screens are now supplied down to O'l mm. 
lay Messrs. J. & P. Pool, Ltd., Hayle, Cornwall. 

02 



20 



METHODS OP STUDY OP SANDS. 



being of smaller diameter than the apertures. Accurate grading 
caunot then be carried out. 

A plea must be made for uniformity in the expression ot grade- 
sizes, preferably in millimetres. The brass screens in use in this 
country for soil-analysis and other grading work, while often made 
according to metric units (frequently in Germany) are in nests ot 
2 mm., 1 mm., 0'5 mm., and 0'25 mm. diameter holes, the last 
being square wire-mesh, and the others punched round holes. In 
some of the literature on mechanical analysis of sands, the last 
mesh-size or elutriation -size is taken at 0'2 mm. diameter instead 
of 0'25 mm. It is then difficult to institute comparison between 
analyses. The size 0'25 mm. diameter is adopted here, on account 
of the exigencies of the apparatus used. 

(b) Elutriation. For determining smaller grades of sand, 
screening should give place to elutriation. The process of elutrin- 
tion is a classification of particles according to size by means of 
upward currents of water. The final velocities attained by small 
grains of a particular mineral of known size, when they are allowed 
to settle freely in water, have been determined both by calculation 
and experiment. The results have proved to be remarkably con- 
cordant and indicate that the controlling factor in the settling of 
small particles is surface-area, and not density. The free settling 
of particles in a liquid is due to gravity, but the velocity attained 
is controlled by the viscosity of the liquid. The settling of ^ grains 
of diameter up to about 0'2 mm. thus conforms to a law which has 
been termed* " the law of viscous resistance." The velocity varies 
as the square of the diameter of the particle. The settling of 
grains above about O2 mm. diameter is controlled by another law, 
that of " eddying resistance,-" where the velocity varies as the 
square-root of the diameter. Elutriation, hoAvever, is concerned 
only with separation of grains up to about 0'25 mm. diameter ; 
above that size, sifting is usually adopted. In elutriation the 
assumption is made, and lias been found to be justifiable, that the 
final velocity of any grain of known size is approximately that of 
the upward current of water which will just keep the grain in 
suspension. The process enables us to classify sediments into 
grades, if desired, down to a limit of 0'005 mm. (about 0-0002 inch) 
diameter. 

The velocities of water-currents required for separating [suitable 
grade-sizes are as follows : 



0'4 mm. diameter, 

0-3 

0-25 

0-2 

0-1 

0-05 

0-01 



47 
32 
25 
20 
6-7 
1-78 
0-12 
(Temperature 15 C.) 



mm. per second. 



* Sir Q-. G-. Stokes deduced the law on purely theoretical considerations. 
Richards, ' Text-book of Ore-Dressing, ' New York, 1909, p. 264. 



21 



The viscosity of water decreases rapidly with rise of temperature. 
The grading of sands is controlled by this viscosity, and cold water 
will therefore cany off larger grains than warm water for any one 
head and jet in elutriation. Care must be taken always to elutriate 
at approximately the same temperature. The difference in tem- 
perature of tap- water in summer and winter is sufficient to alter 
appreciably the results obtained in grading a fairly coarse sand. 

The two chief forms of elutriators used by the writer in the 
investigation of sediments are the Crook pattern and a modification 
by Stadler of the Schoene type. The former apparatus *, designed 
by Mi-. T. Crook of the Imperial Institute, is simpler to make and 
work and enables a mechanical analysis to be made more rapidly 
than the Schoene, many grades being separated at once. The 
apparatus will be best understood from the sketches. The Crook 
elutriator consists (Pig. 2, page 22, & Plate I. fig. 1) essentially of 
two cylinders, a lower narrow one A and an upper broad one B. 
In order to obtain a constant rate of flow upwards for the water in 
these cylinders a small movable reservoir C is used, with an over- 
flow funnel and tube D. The reservoir C can be moved up and 
down, and a constant head and pressure of water may be obtained 
in the apparatus when these vary in the water-taps of the labora- 
tory. The vessel B is fitted with a double-holed stopper through 
which passes a straight tube E acting as a manometer, and a bent 
tube F with a jet at the end. The velocity of the upward current 
of water in A and B is regulated by the size of the jet-opening, and 
the height of the water-level in C, which may be moved up and 
down ; the velocity is indicated by the height to which the water rises 
in E. For separation of the sediment into sand-, silt-, and clay- 
grades (1 mm. to 0-1 mm., Ol mm. to O'Ol mm., and less than 
O01 mm. diameter) the internal areas of cross-section of the cylin- 
drical parts of A and B must be closely in the ratio of 1 to 50. 
Convenient sizes are found to be 1-4 cm. diameter for A, and 
9-8 cm. diameter for B, in which case to obtain the required 
upward velocities of the water, of nearly 7 mm. per second in A, 
and 0-15 mm. per second in B, the jet F is found to bo about 
1 mm. diameter, and must permit an outflow of nearly 100 c.c. in 
90 seconds. The outflow is controlled and varied by movement 
of C, and when the correct measure is found, the height of the 
water-column in E is marked and should be kept constant. The 
tube A should be about 30 cm. long with a slight constriction in 
the drawn-out bottom end (wliich may also be roughened) to 
facilitate the grip of the rubber tube upon it. The vessel B is 
about 14 cm. long in the conical part and 12 cm. long in the 
cylindrical part. The lower portion of B and the tube A should 
be of the same diameter and joined by rubber tubing of the same 
internal diameter fitted with a clip. Another clip is used to cut 

* T. Crook, Appendix to Hatch & Rastall, * Sedimentary Rocks,' London, 
1913, p. 349. Apparatus made by Messrs. A. G-allenkarnp & Co. Ltd., Fiusbury 
Square, London, J. Monorieff, Ltd., Perth, and Muller, Oione & Co., 148 High 
Holborn, London, 



22 



METHODS OF STUDY OF SJJS'DS. 



off A from C. Other details will commend themselves to the* 
user of the apparatus. A weighed quantity of sediment (10 or 
20 grammes) sifted to 1 mm., after being suitably treated if clay is 
present (boiled with water and deflocculated by the addition of pyro- 
gallol or such an alkali as ammonia or Avashing-soda) is introduced 
into B. When the clips are released, the upward cm-rents of water 
separate the material into grades, the sand-grade from 1 mm. to- 

Fit?. 2. Crook's Elutriator. 



A. Lower cylinder for sand-grade. 

B. Cylinder for silt-grade. 

C. Movable reservoir giving head of water. 

D. Overflow tube. 

E. Pressure-gauge. 

F. Outlet tube and jet. 




0-1 mm. diameter being buoyed up in A, the silt-grade from 01 to 
0-01 mm. diameter being held in suspension in B, and the clay-grade 
being earned over by the water through F. The last grade may be 
collected in large jars and allowed to settle. The water may then 
be decanted off, and the sediment dried and weighed As it is 
sometimes necessary, Avith clayey deposits, to keep the apparatus 
going tor 12 or more hours, until the separation is complete 
(shown by clear water passing over from B), a very large bulk 



ELUTETATTON. 23 

of water accumulates, and settlement takes much time ; moreover, 
the fine clayey material is difficult to deal with. When separation 
appears to be complete, the screw-clip between A and B should 
be closed a little for a short time before the grades in A and B 
are finally clipped off from one another. It is the usual practice, 
after drying and weighing the separated grades in A and B 4 to 
find the grade of < -01 inin, diameter by difference. The proportion 
of material of diameter > 1 mm. may be found by sifting before 
elutriation. The grading obtained by this apparatus is there- 
fore >1 mm., >O1 and <1 mm., >CK)1 and <0'1 mm., and 
< O'Ol mm. As it is often desirable to know the percentages of Hne r 
medium, and coarse sand, the dried portion of diameter > - 1 and < 1 
mm. may be subjected to sifting through 0*5 and 0-25 mm. sieves. 

In the case or time sands, very little material should be found 
in B or pass over through F. The height to which a knoAvn 
weight of sand is borne up in A during the experiment gives the 
observer an idea of the proportion of the coarse, medium, or fine 
sand-grades. For example, in the elutriation of Fontainebleau 
sand, a seething mass ot grains. 10 cm. high, with a sharp upper 
limit and almost clear column of water above, is seen in A. The 
sharp upper limit indicates a high percentage of one grade such as 
coarse sand, medium sand, etc. An indefinite, hazy border, or the 
complete occupation of A denotes a niixture of grades, and the 
sand is therefore not of the best for glass-making. Crushed rocks 
invariably give the latter result. 

The great feature of Crook's apparatus is its simplicity and 
rapidity of working. By adjustment other grades than those 
>1 mm., >0'1 mm. and <1 mm., >0'01 and <0'1 mm., and 
<0'01 mm. can be separated. The Schoene apparatus (or its 
modification here described) enables grades between any desired sizes 
to be separated, as many as eight or nine grades being obtained if 
desired. The apparatus requires much more attention, and, since tbe 
grades are separated one at a time, a complete analysis of a sediment 
may take a considerable time (sometimes a week of working days). 

The Stadler modification of the Schoene apparatus * is repre- 
sented simply in Fig. 3, page 24, and Plate I. fig. 2. Essentially 
it consists of a cylindrical vessel A about 40 cm. long and 5 cm. 
in diameter drawn out and bent round at the bottom, and fitted at 
the top with a stoppered funnel B, and outlet tube C. The tube 
C divides into the vertical piezometer tube D which registers the 
pressure and therefore the velocity of water passing through A, 
and a jet E. The tank F gives a fixed head of water; the latter 
passes down the tube Gr, controlled by a stop-cock H, into A. 
A short length of glass tubing and a clip are attached to the 

* H. Stadler, loc. cit. p. 689. Made by Messrs. Griffin & Co., Zingsway, 
London. Mr. T. Crook suggested a modification of the Sohoene apparatus, 
using jets of varying size, in Roy. Dublin Soo., Eoon. Proo. vol. i. pt. 5 (1904) 
p. 267. On elutriators generally, see Keilhack : * Lehrbuob der praktischen 
Geologie,' 1908, 2nd ed., Stuttgart, and Edes : ' Clays, their Occurrence, 
Properties, and Uses,' 1908, 2nd ed., New York. 



METHODS OF STUDY OP SANDS. 



lower end of A, which may be fitted with a glass stop-cock. The 
tube D is about 100 cm. long and is suitably graduated. A 
aeries of jets (best made by the operator and standardized with 
the instrument) with holes from 2 mm. diameter down to an 
extremely small size (about 0'25 inna.) are fitted in turn at E. 
Knowing the internal diameter of A, and measuring the volume 
of water outflowing per second from each jet, we can plot curves 
and draw up a table showing the jet used and the piezometer 
reading for all the velocities of water in A we require. 

Fig. 3. Stadler's modification of the Sclioene JSlutriator. 





1=-* 

F 



A. Elutriating; cylinder. 

B. Intake funnel for sediment. 

C. Outlet tube. 

D. Piezometer. 
B. Variable jet. 

P. Tank to provide fixed head of 
water. 

G. Connecting tube for water-supply. 
H. Screw-tap. 




. A weighed quantity of sediment, previously treated as described, 
is washed down through B into A, and separated into grades com- 
mencing with the finest, by attaching the proper jet E and suitably 
adjusting the water-level in D by means of 'the screw-tap H. 
To distribute the water-current entering A, shot or mercury may 
be placed at the bottom. The grades are thus separated one at a 
tune and the procedure is slow, so slow, indeed, as to give time for * 
complete settlement of the finest grades as they come over, and 
permit decantation and estimation. The grades to be separated will 
depend on the nature of the investigation. Mr. H. Stadler, while 
at the Royal School of Mines, classified battery-pulps in a series of 
grades in a reduction ratio of the weight of a grain of each grade of 
four to one. For glass-sands, moulding-sands, and general geological 
work, it is more advantageous to adhere to the classification detailed 



ELTTTBIATION. 



25 



above, but the apparatus permits the estimation of certain useful 
intermediate grades ( > O01 and < 0'05, > O05 and < 0*1 mm. etc.). 
The relative advantages and disadvantages of the two forms of 
apparatus cannot be discussed here, but it may be repeated that 
for work dealing largely -with deposits which are essentially sands, 
Crook's apparatus, combined with careful sifting, is simpler and 
more rapid in its action. The wide cylinder B in Crook's elutriator 
may be substituted for the cylinder A in the Schoene apparatus, 
giving greater accuracy in the separation of the fine grades, while 
using the latter apparatus. 

As some difficulty has arisen at the present time in getting the 
necessary glass-ware blown for such elutriators as that designed by 
Crook, it may be of service to give a brief account of the single- 
vessel elutriator which can be constructed from wide glass tubing 
usually kept in stock. Tubing one and a half, two, or three inches 
in diameter is eminently suitable for all but the small grades of 
diameter less than 0-05 mm. By changing the head of water, 
small differences in velocity may be obtained, but for such variation 
as is required for the separation of suitable grades of a sand, the 
size of the outlet must be varied by means of jets of differing 
apertures. 

The single-vessel apparatus is indicated in Fig. 4 (page 26). 
Separation of the grades takes place in the tubular vessel A. The 
length of the vessel is a matter of importance, and the lower 
drawn-out conical portion should be equal in length to the upper 
cylindrical part. For two-inch tubes, each should be about 8 inches, 
but for the separation of grades in three-inch tubes, 6 inches for 
each part is sufficient. It is advisable to have the lower end of the 
tube opened out slightly to enable the rubber connexion tubing 
to obtain a grip upon it. A constant velocity for any one jet is 
obtained by adjusting the height of the vessel B, which gives the 
head of water. The vessel A is fitted with a two-holed rubber 
stopper, into which are inserted the manometer tube C and the 
outlet tube D fitted with the jet E. When the desired velocity of 
water passing through A is obtained for any one jet, the height 
of the water in C is marked. The area of cross-section of A is 
determined accurately, and a number of jets may be standardized to 
give the required velocities by measuring the outflow yielded by 
each. Small differences in velocity may be adjusted by raising or 
lowering B. Approximate sizes of jet-holes and head of water, usirig 
the two-inch and three-inch cylinders, are as follows : 





2-iiich (51 mm.) 
cylinder. \ 


3-inch (76 mmj 
cylinder. 


Diameter of grains separated 
jet-aperture ... 
Head of water 


mm. 
0-4 
7 
1880 


mm. ' 
0-2 
3 
1400 


mm. j mm. 
0-1 I 0-05 
3 2 
700 j 400 





26 



METHODS OF STUDY OP SA1TD3. 



As in the Schoene apparatus, described on page 23, successively 
coarser grades are run off, one at a time, beginning with the smallest. 
The Schoene apparatus differs in having a fixed head of water. 

Fig. 4. A single-vessel JForm of Elutriator. x fa. 



Water 
Inlet. 



A. Elutriating Cylinder. 

B. Movable reservoir giving 

bead of water. 
G. Pressure-gauge. 

D. Outlet-tube. 

E. Jet. 

T. Spring- olip. 




Usually two or three jets to each cylinder will be found to be- 
sufficient. The jets may conveniently be made of glass-tubing, 
partially closed in the blow-pipe flame and blunt-nosed. Each is 
attached to D by rubber connexion-tubing, close up so that the- 



GRADE-SIZES OP BAUDS. 27 

glaas parts are touching. Care should be taken that if the rubber 
or glass-tubing connecting A and B is replaced by longer or wider 
material, the overflow should be remeasured and any necessary 
correction of head made. Friction plays a very great part in 
retarding the flow of water through tubes, especially when the high 
velocities necessary to grade to O3 and o4mm. are obtained. The 
tubes connecting A and B are therefore made as wide as possible, 
and they should not be changed in length or diameter nor should 
rubber be replaced by lengths of glass, without checking all 
velocities again. (These remarks apply als,o to the Crook and 
Stadler elutriators.) 

The accuracy of the ehitriation processes has usually been 
checked by examination and measurement of grains from the 
separated grades under the microscope. A word of warning is here 
necessary. In data relating to mechanical analyses of sediments 
(for example, moulding-sands, fire-clays, etc.), the average diameter 
of the grains constituting each grade is given. Both geologists 
and mining-engineers have found that the average diameter 
obtained by microscopic measurement has usually too high a value. 
When almost spherical grains of known specific gravity from 
any one grade are counted and weighed, the average diameter 
may be found by calculation. This value is usually less than 
that obtained by microscopic measurement, because the grains 
are rarely true spheres. They tend to lie in their "flattest" 
position, and thus the minimum diameter is usually not measured. 
Particularly is this the case with certain crushed minerals, among 
which is quartz. Quartz, although it has no cleavage, tends to 
crush into a very flaky form, and elutriation products of this 
material, which has been recommended as a glass-sand, always appear, 
when examined under the microscope, to be coarser than they 
really are (compare, for example, figs. 2 and 6, Plate IV.). 

It is an interesting fact that the average diameter of the grains 
of a sand is frequently a very small figure which is not at all the 
size of grain that appears to the eye to be representative of the 
sand. An example will best illustrate the point. 

Taking a well-graded, washed sand, such as that from Lynn, of 
mechanical composition: >0'25 and < 0'5 mm., 9O8 % ; >O1 
and < 0-25, 8-7 % ; > O'Ol and < O'l, 0-2 : / ; < 0-01, 0-3 % ; we 
find that the true average diameter (the sum of all the diameters 
divided by the number of grains) is OO103 mm. This appears to 
be a very low figure, and is due to the fact that even in a tiny 
' percentage of a small grade an immense number of grains occur. 
(Care must, of course, be taken before elutriating to ensure that 
.the sand is dry, or moisture may be* estimated as clay-grade by 
difference.) Lynn Sand was chosen as being one of the best-graded 
materials. The average diameter of Lippe Sand (see page 131 
and Plate III.) similarly worked out at 0'009 mm. If, however, 
we multiply the percentage weight of each grade by the average 
size of that grade, add together the results and divide by the total 



METHODS OF STUDY OF SANDS. 

percentage weight (t. e. 100), a method adopted by H. Eies*, 
we obtain a result which' is certainly not the average diameter, 
but which is a size apparently representative of the sand when 
examined and measured under the microscope. In the case of 
ihe Lynn Sand above, it works out at 0-285 nrm. The latter 
result might be termed the " dominant diameter " ; it has been 
called erroneously the average diameter. That it is not the latter 
may easily be seen by making a similar calculation upon a sandy 
clay. 

In connexion with the underground passage of water through 
.sands, Hazen desired to find the mean or average-sized grain of 
each sample f. This mean size he termed the effective size, and 
it was to be such that, if all the grains were of that diameter, the 
sand would have the same transmission capacity that it actually 
possessed. Hazen adopted screening, and decided that the effective 
size should be determined from the mesh of the sieve which allowed 
10 per cent, to pass and retained 90 per cent, by weight of the 
sand. The variety of sizes present in a sample he indicated by the 
uniformity coefficient. To determine this, he found the size of 
the sand-grain such that 60 per cent, was of smaller and 40 per 
cent, of greater diameter. Then the uniformity coefficient 

"tlllS Si Zf 1 

= ~~at- ~ - ' Hazen found that 10 per cent, of small grains . 
etrective size r 

had the same effect on water-flow as 90 per cent, of the larger 
grains, provided that the uniformity coefficient was not greater 
than 5. 

The uniformity coefficient for the majority of British sands here 
described (dominant grade == medium sand >0'25 and < 0-5 mm. 
diameter) is nearly 2. , 

(c) Graphical Expression of Results. The expression of 
mechanical analyses in the form of curves brings out contrasts 
and similarities in sediments more graphically than does the use 
of space (e. g. " strip " or " butterfly ") diagrams. Similar graphs 
have been used for screening-analyses in connexion with water- 
supply and pei-colation, in the publications of the United States 
Geological Survey, and for analyses of moulding-sands in. those of 
the Geological Survey of Denmark. The curves here drawn are to 
be regarded as approximations only, serving to visualize the lists of 
figures given in the tables of mechanical analyses. Reference 
should always be made to the latter. Cumulative percentages by 
weight of material above the grade-size (marked horizontally) are 
set off vertically as ordinates. For example, in the curve XW ' 
(Fig. 5) representing a specimen of London Cky, about 17 per 
cent, of the sample is of diameter greater than O'l mm. and about 
55 per cent, of diameter between O'l and 0-01 mm. ; the ordinate ' 
at the latter grade-size is therefore 17+55=72 per cent. The 

* Trans. Amer. Foundrymen'B ABBOO. 1906, page 63. 
f 0. S. Sliohter, " Motions of Underground Waters." Water-Supply and 
Irrigation Papers, U.S. Gaol. Survey, No. 67 (1902). 



^s* 

^? ; 

.'.'" ':f /" ^> 

EXPHESsroaf. 1 *--Y 29" :* 

" l ^- I I H R A R V j ' 

horizontal scale adopted is proportional to th^tpgarrthms or the- / 

diameters quoted, in order to keep the scaltT representing the- V X''^> 

^K .^ 





various grades down to clay within the compass . 

The curves are plotted from four or five points,' witfr m 
for intermediate points obtained from microscopic examin.. 

Horizontality in any part of the curve means the absence ofTnt? 
grade-size, corresponding to the distance that such horizontality 
extends. Verticality in the graph means a considerable percentage 
of the grade-size corresponding to the position of the vertical 
portion. In the figures for glass-sands and other similar well- 
graded sands the verticality is probably greater than represented, 
but the absence of information as to percentages of intermediate 
grades prevents more accurate plotting. All the curves eventually 
turn up at the right-hand eud (in the clay-grade portion) when 
the total reaches, as it must do, 100 per cent. The approach to the 
upper line may be asymptotic, i. e. the particles may gradually 
become smaller and smaller to vanishing point; but it is more 
probable that in most sediments a lower limit of size of particle is- 

reached, when the curve turns up thus ', Probably solution 

eventually causes the disappearance of tiny particles "before they 
disintegrate mechanically. 

Representing the mechanical composition of a sediment as a 
curve (Fig. 5) obtained by plotting cumulative percentages of the- 
various grades against the diameter of particles in the grades, we 
see that a pure gravel, 100 per cent, of diameter not less than about 
2 mm., is represented by the vertical line AB, a pure sand of 
medium grade by CD, a pure silt by such a line as EF, and a 
pure clay by another vertical line such as G-H beyond. Such ideal 
sediments do not seem to be present in nature. The curves TU, 
WX, and YZ represent actual British sediments which have been 
subjected to mechanical analysis. The curve TU is that of a true 
medium sand from. the shore at Kynance Cove, Cornwall, WX is- 
a true loam, worked for brick-making, from the London Clay at 
Ipswich, and YZ is a true clay of Upper Glacial age from 
Hasketon, Suffolk. These three sediments approach very nearly 
to the highest perfection to be expected from natural deposits. 
With them should be compared the curves indicated in Fig. 6,. 
which are of some well-known and successful moulding-sands. 
The upper curves, representing the famous "Belgian Red" and 
"Cornish Red" (Pliocene Beds, St. Erth, Cornwall) moulding- 
sands, etc., are clearly from their position indicative of coarser- 
sediments than the other represented, which is the well-known 
"Erith" sand from Charlton (Kent), much finer in grain. In spite 
of the variation in size of the constituent grains, the proportion 
of the grades is constant and causes the curves to be remarkably 
sympathetic. The graph of the "Belgian Red" moulding-sand is 
seen from the figure to cut across the others, owing to that deposit 
containing a greater proportion of clay, apparently, ferruginous 
kaolin. ActuaUy it is more nearly the ideal moulding-sand expe.cted 
on theoretical grounds, i. e. one with high clay-grade fo. J bJjad T: aflj]l, 



1179 





30 METHODS OF 8TTJDT OF SANDS. 

Fig. 5. Mechanical Analyses of Sediments : Graphical representation. 
. Sand . Silt x __Clay 



100^ 






A /*"" U 


go 




x E 
I. 


G 








1 


w. 


x/ 








X 








eo 




| 




^ 




60 




4* 




s<5> 




1 70- 




e| 




^ 




<u 

w 3 eo 

C 




fi 

0* 




/*' 


Z 


2 50- 




u l 

u 1 




& 


' 


Q) 










* 


c. 








4 




5 40 






v x 


e 




ra 

= 30 




?* 


0^ 


// 




E 




m 1 


<>x 


jpO 




a 




y 


^v 


f 




V 20 




| 


V f 


s-jpo 




f 




1 

K 


/ 


<^o^ 




10 




J 


D ' F 


$$' 






B 


.T^/ 


^ vV . VL ^-o 


>~ H 





2-0 



1-0 



0-5 0-25 0-1 0-05 

> Grade Sizes (diameter in Millimetres} 



0-01 mma 



Fig. 6. 



Analyses of Sands : Moulding- and Glass-Sands 
compared. 



Sand x '-Silt *---Clay 




2-0 



l-O 



0-5 0-25 0-1 0-05 0-01 

'Grade Sizes (diameter /'" Millimetres) 



EXPRESSION. 



31 



Fig. 7. Mechanical Analyses of Sands. An attempt towards 
representation of Ideal Q-lass- and Moulding- Sands. 

irtn?a. <-- Sand < Silt ---,- .g Clay --- 



90 . 

^ 80 . 
oo 
I 70 . 

3 60 J 
S 50 . 

Q_ 

-^ 40 

JO 

3 

I 30.- 

T 20 . 

10 . 




2-0 



i-O 



0*5 0-25 0-1 0-03 O-OI. 

>Grade-St2es f diameter in Mil/trnetres) 



Fig. 8. Mechanical Analyses : Unsorted Deposits. 

-Gravel -x:- Sand -- ,->< -.-Silt ><--Clay-- 




4-0 ,2-0 



1-0 0-5 -Q-.25 0-1 0-05 

-* Grade Sizes (diameter in Millimetres) 



32 METHODS OF STUDY OF SANDS. 

with a good quantity of sand-grade (other than fine sand) for 
openness and ventilation. The ideal moulding-sand for "greensand 
moulding " would he graphed as in Fig. 7, AB, the horizontal part 
of the curve passing over the fine sand- and silt-grades. Some of 
the Pliocene, Eocene, and Cretaceous Beds fringing the kaolinized 
granite-masses of Devon and Cornwall approach very closely to 
this ideal. Moreover, the clay-grade is composed largely of kaolin, 
the refractory properties of which are excellent. The difficulty to 
he solved is that of making the kaolin, which is not a very plastic 
clay, into a good "hind." 

Fig. 9. Mechanical Analyses : possible variation in true sands. 

+ Sand -X Silt -$H<- - Clay- 




2-0 1-0 0-5 0-25 0-1 0-05 0-01 mms. 

-> Grade 5i7es /diameter in millimetres) 

On the other hand, a perfect glass -sand should be all of one 
grade, preferably among those sizes not so desirable in a moulding- 
sand. In other words, a sand from which glass is to be made 
shotdd have all its grains of one size, not greater than Q-5 mm. 
or less than O'l mm. diameter. The curve CD (Fig. 7) would 
represent such a sand. 

With these ideal cases should be compared those of Fig. 8, " 
representing such unaorted deposits as those mentioned in 
Chapter II. The curves in Fig. 9 show the possible variations 
in grade of British sands, and from a comparison of Fig. 9 with 
Figs. 10 & 11, page 50 (see also Plate III. figs. 1-5), the special 
grading of sands for glass-making will be realized. The badly- 
graded products obtained by crushing rocks are indicated in Fig. 12, 
page 79 (see also Plate III. fig. 6). 



GLASS-MANUFACTURE. 83 



CHAPTER IV. 



Literature on G-lass- Sands, etc. Comparatively little appears to 
have been written upon the important subject of glass-manufacture, 
and especially in this country is there a dearth of literature bearing 
upon the problem. Only a small amountj too, of the available 
literature refers to modem processes and developments. For those 
interested in the methods used, and those .who desire to realize 
to what extent knowledge of our geological resources may help 
the trade, the following works are recommended : 

Glass Manufacture (Constable), by Walter Kosenhain, 1908. 

Glass (Sir Isaac Pitman & Sons), by P. Maraon. Just published. 

The Prinoipleirof Glass-making- (G. Bell & Sons), by Powell and Chance, 

1885. 
Glass. Articles in ' Enoyolppaadia Britannioa,' llth edition, by Harry 

J. Powell and W. Rosenhain. 
Jena Glass (MacmiHan & Co.), by Hovestadt ; translated by J. D. and 

A. Everett. 

Glass-blowing and Glass-working, by Thomas Bolas, 1898. 
Abridgments of Patent Specifications of Glass : 10 volumes, 1855-1915. 
Glass-blowing, by W. A, Shenstone, 1886. 
Glass : Article in Thorpe's Dictionary of Applied Chemistry, 1912. 

Le Verro et le Criatal, by J. Hemivaux, 1897. 

La Vevrerie an XXme Sieole, by J. Henrivaux, 1911. 

Die Glasfabrikation, 2 vols., by E. Dralle and others, 1911. 

Die Glasfabrikation, by K. Gerner, 1897. 

Die Herstellung grouser Glaskorper, by C. Wetzel, 1900. 

Die Glasmduatrie in Jena, by E. Zschimmer, 1909. 

Glas : being Part I. of Ghemischo Teohnologie, by B. Miiller, 1911. 

Die Glasatzerei, by J. B. Miller, 1910. 

Zeitgemasse Herstellung, Bearbeitung, und Verzierung des feineren 

Hohlglases, by E. Hbhlbaum, 1910. 

Die Bearbeitung 1 des Glases anf dem Blasetisoh, by W. Lermantoff. 
Scbmelzen nnd Krystallisieren, by G. Tammann. 
Die feuerfesten Tone, by C. Bisohof . 

The following catalogues and periodicals may usefully be con- 
sulted : 

Catalogue of works on glass in the Library of the Society of Glass 

Technology. 
Catalogue of works on glass in the Library of the English Ceramic 

Society. 
Catalogue of works on glass in the Public Reference Libraries of 

Birmingham, Leeds, and Manchester, 1913. 

D 



34 GLA-SS-MAJSTUFACTTJEB. 

Catalogue of works in the Patent Office Library dealing -with Ceramics 

and Glass, 1914. 

Spreehsaal Kalendar, annual volumes. 
Periodicals : 
Die Glaainduatrie. 
Spreonsaal. 
Glashiitte. 
Diamant. 

SUlkatB-ZeitBohrift. 
Keramisohe Rundsohau. 
Tonindustrie Zeitung. 

Journal of the Society of Glass Technology. 
Transactions of the Optical Society. 

English. Ceramio Society. 

American Ceramio Society. 

References to other scattered papers, etc., and to additional French 
and German literature, will be round in the works cited above. 

Lists of formulae for various glasses have recently been issued by 
the Institute of Chemistry *. Others are supplied confidentially. 

On the important question of glass-sands, less still has been 
written; indeed, the literature may almost be said to be non- 
existent. In veiy few countries do we know the properties, 
quantity, and workability of the Band-resources generally, and 
little of this knowledge concerns glass-sands. 

No thorough discussion of the properties and desiderata of 
glass-sands is known to the writer. Scattered notes are to be 
found in publications of the Q-eological Surveys of the United 
States, Denmark, etc. These are referred to in their appropriate 
places hereafter t- 

The dearth of literature upon glass-sands in this country is 
doubtless due to the fact that before 1914 manufacturers of 
glass in the United Kingdom used large quantities of foreign 
sands, notably from France, Belgium, and Holland. The use 
of such imported sands, frequently to the entire exclusion of 
our own resources, was due to two main causes : in the first 
place, the sands were generally purer than the obtainable British 
sands, and, in the second, the cost was less, particularly when 
foreign sands were brought back as ballast on a boat's return 
journey. The latter state of afEairs arose because the British 
.supplies of sand were frequently situated inland ; thus the cost 
of transport by water from abroad was less than that by rail from 
one part of the country to another. So little has Britain investi- 
gated and relied upon her own resources of sand, that it is not 
surprising to find a Q-erman writer upon glass-making declaring 
-categorically in 1885 that the English sands were iron-bearing, 
while only those of the Isle of Wight were considered worthy of 
mention. It is stated that the English obtained glass-sand from 

* Proceedings, 1915, Parts ii., iii., & iv. 

f Since the above was written, there has appeared a discussion of the 
^lass-sands of the U.S.A., by Pettke, Trans. Amer. Cer. Soc. 1917, vol. 19, 
page 160. 



BAW MATBHIALS. 



.35 



France, America, and Australia ! * Such statements are hardly 
correct; for as far back as 1858 Northampton Sands, Ashdown 
and Tunbridge Wells Sands, Aylesbury sands, Aylesford sands, 
Lynn sands, Thanet Sands, Bagshot Sands, and others were 
.already in use f. 

Tscheuschner, the German writer referred to above, mentions that 
glass-sands were obtained in France from Maintenon, Fontainebleau, 
Nemours, and Champagne ; and in the Q-erman Empire from 
Nievelstein in the Rhine Province, Hohenbocka in Prussia, and 
Lemgo in Westphalia. 

Raw Materials : Importance of Sand. The various kinds of 
glass may be regarded as mixed silicates (and, to a smaller extent, 
borates) of the alkalies, sodium and potassium, the alkaline earths, 
calcium, barium, magnesium, etc., and lead, iron, zinc, and 
aluminium. 

' Probably the silicates, borates, and oxides are in a state of 
mutual solution in one another; but, just in the same way as 
much dispute exists among petrologists as to the combinations 
into which the various elements enter in a natural molten rock- 
magma (of which a natural glass such as obsidian is only a 
solidified form), so authorities on the chemistry of glass are by no 
means agreed upon tbe actual compounds formed. The geologist 
is mainly concerned with the fact that the finished product, glass, 
consists of 60 to 75 per cent, of silica, which is contributed 
to the raw mixture in the form of a sand. 

The " batch 1J or mixture of raw materials such as sand, soda- 
.ash CNa.COJ, salt-cake (Na S0 4 ), potash (as K a CO ? or KNO a ), 
limestone (CaCO,,), red lead (Pb^OJ, manganese dioxide (MnO a ). 
coke or anthracite (C), alumina (A1 2 3 ), boric anhydride (B a 3 ), 
barium carbonate, calcium fluoride, etc., according to the kind of 
glass required, usually consists of 52 to 65 per cent, by weight 
of sand. A small amount of silica is sometimes added in the 
form of felspar; but the percentage of silica is increased in the final 
product (which, when molten, is termed "metal"), as a result 
of the loss of such gases as S0 2> C0 a , etc. The silica-percentages 
in some well-known glasses are as follows : Window 53 per cent,, 
lead flint 53 per cent., soft soda (chemical laboratory ware, X-ray 
tubes, etc.) 54 to 56 per cent., green bottle 57 per cent., miners' 
lamps 59 per cent., combustion tubing 60 to 62 per cent., plate 
62 per cent., resistance (very like Jena) 63 per cent., soda-lime 
(Venetian) 73 -4 per cent., potash-lime (Bohemian), 71'7 per cent., 
1 .and so on, the proportions varying somewhat in actual practice. 

In point of bulk, therefore, the sand is the most important 

* 'Handbnch der Glasfabrikation,' B. TschenBonner (Weimar, 1885), 
page 72. AnalyBes of various glass-Bands are also given in Dralle's ' Die 
Glaafabrikation,' and of German glass-sands in the 'Spreohsaal Kalendar' 

t 'Mineral Statistics : Mem. Geol. Snrvey (1860, being Part ii. for 1858), 
-.page 874. 

D a 



86 GLASS-MAJSTIFACTUEE. 

ingredient, and its properties influence to a large extent the 
character of the glass obtained. 

As emphasizing the bearing of the sand used upon the qualities 
of the glass, an example given by Hovestadt may be quoted. 
Thermometer-glass, made in the Thuringian Forest district, owes 
its special quality to certain sand found only in the neighbour- 
hood of the village of Martinroda. The glass withstands repeated 
melting, blowing, and fusing without change ; while ordinary 
glass, such as that of windows, becomes rough and dull of surface 
even after short exposure to the flame. Other sands are believed 
to be unsuitable, especially the pure sand from Brandenburg. 
The cause of excellence is attributed to the alumina present, 
which forms 8'66 per cent; (page 21, Everett's translation). 

The raw materials used in glass-manufacture may be conveniently 
grouped, from the geologist's point of view, into two classes : 
(a) Bocks and minerals such as native silica (in the form of vein- 
quarfci, sands, sandstones, or quartzites), felspar, kaolin, limestone, 
anthracite, fluorspar, cryolite, etc., which are used, except perhaps 
for washing, in the state in which they aj-e won ; and (b) Chemical 
products which have been prepared from naturally-occurring sub- 
stances. Among the latter are salt-cake, soda-ash, borax and boric 
anhydride, potash, alumina, arsenic, and compounds of lead, barium, 
manganese, cobalt, chromium, nickel, zinc, and other metals. 

The resources of silica, potash-felspar, and kaolin are referred to 
in the following pages. No difficulty exists in obtaining fairly 
pure limestone (that from Buxton in Derbyshire is most widely 
used) and anthracite. Cryolite is indirectly imported from Green- 
land and does not occur in the United Kingdom, nor is it known 
to occur in the British Empire ; the resources of fluorspar have 
recently been dealt with in a publication by H.M. Q-eological 
Survey *. 

Of the second group, the minerals from which potash can be 
obtained are mentioned hereafter. British resources of alumina 
have yet to be described in detail. Those of barium (as barytes 
and witherite) and manganese ores have been dealt with by 
H.M. Q-eological Survey t- Ores of arsenic and zinc occur in 
Great Britain, but the resources have not at present been syste- 
matically described. The minerals which yield boron compounds, 
cobalt, chromium, and nickel are imported from abroad, and are 
used in small quantities only. 

Colour etc. of the Glass. Upon the sand depend the trans- 
parency, brilliancy, lustre, and hardness of glass. The uniform 
density of glass, as will be seen in the sequel, is influenced to no 
small extent by the mechanical composition of the sand. In 

* Special Eeports on the Mineral Resources of Great Britain, vol. iv., 
Fluorspar; (1916). 

f Ibid. vol. i., Tungsten and Manganese Ores ; vol ii., Barytes and 
Witherite. 



THE PEOCESS OF GLASS-MAKING. 37 

order that the finished article may have plenty of "life," and 
the sparkle and " water-whiteness " of the best glass, due attention 
must be paid to obtaining, and treating suitably, the sand itself. 

For optical glass and table-ware ("crystal" and "cut-glass") 
only the purest sands can be used. 

Where the glass is blown or rolled into thin sheets, as in the 
making of laboratory-ware, lamp chimneys, incandescent electric 
globes, window-glass, etc., the requirements are not so exacting, 
but the sand must still be fairly pure. The light passes through 
only a small thickness of glass, which, although possessing a 
slight colour when seen in a thick mass (sometimes a faint green 
due to the small quantity of iron in the sand, at others a faint 
pink due to manganese which has been added in the form Mn(X 
as a corrective to the iron), appeal's colourless and has plenty of 
life in the attenuated state. The colour may then be observed by 
looking at the object " edge-on," that is, through a much greater 
thickness of material. 

While only the merest trace of iron impurity in the sands is 
permitted for optical and cut-glass, less pure sands containing 
O'l per cent, of Fe a 3 may be used for plate- and window-glass, 
. chemical apparatus, globes, etc. 

Small quantities of iron or other impurities are sufficient to 
detract from the lustre of table-ware, or to spoil the power of 
transmitting light possessed by lenses and prisms of optical glass. 

Coloured glasses are prepared in one of two ways, the more 
common being that of adding a chemical compound to the batch, 
and thus obtaining either a coloured silicate (chromium, for green 
glass, cobalt for blue, etc.), or reduction to a very finely-divided 
metallic state (copper or gold for ruby gkss). The other method is 
known as "flashing," and consists in covering the surface of 
colourless glass with a very thin coating of a coloured material 
(e. </., copper or gold ruby glass, which is opaque when only ^ inch 
thick). In either case, to obtain purity of colour, it is essential 
that no amount of impurity such as iron should be present. 

The Process of Glass-maJdng. The manner in which the batch 
is melted to form the glass has also a bearing on the kind of sand 
used and its physical properties. Two different processes are 
adopted. The batch may be placed in open or closed " pots," or 
crucibles, which stand upon a kind of " false-bottom " in the 
furnace. This floor is known as the "siege" (Fr. siege) and 
has "ports" or openings in the middle (or in the end and side 
walls of the furnaces), by which the heated gas and air enter, 
playing around the pots. The pots are arranged around the 
periphery of the furnace to facilitate the extraction of the molten 
" metal " from them as " gatherings " upon the glass-workers' 
iron rods or bio wing- irons. Melting of the batch from the bottom 
upwards is ensured as far as possible. For ordinary glass-work, 
open pots were used; but for special ware, indeed for most purposes 
nowadays, impurities are kept out by using crucibles covered with 



38 GLASS-IIAJTUFACTUBE. 

a hood, " gatherings " being taken through a mouth-like opening 
at the side. 

In the tank-furnace, the batch is melted in a long bath or 
tank constructed from blocks of highly refractory siliceous sand- 
stone. Much larger quantities of material can be dealt with in 
this way; for, besides the larger capacity, the process is a con- 
tinuous one, the batch being fed in at one end of the furnace 
(filling-hole) and the metal being continuously drawn from the 
other, and cooler, end of the tank (working-hole). Special and 
best quality glasses cannot be made in this manner. The tank is 
not covered, and the mixture of burning gas and air, forming 
sheets and jets of flame, enters through ports in the side -walls 
above the surface of the metal. 

When the fusion of the batch is complete, the metal is freed 
from bubbles of evolved gases and entangled air by means which 
vaiy according to the kind of glass made and the craft of the 
glass-maker. This procedure is known as "fining." 

The pots are usually made of fire-clay (or of fire-clay mixed 
with other highly resistant materials), and are very carefully 
prepared. The floors, sides, and crowns of the furnaces are con- 
structed from highly refractory silica-bricks and fire-bricks (e. g. t 
Dinas, Grlenboig, and Stourbridge bricks, etc.), but frequently both 
pots and bricks are partially melted in the intense heat obtained 
in the furnace (1500-1600 C.). Most furnaces are now built on 
the regenerative, and some on the recuperative, principle, by which 
the hot spent gases issuing are utilized to heat the incoming mixture 
of gas and air. 

For the respective advantages of each kind of furnace, reference 
must be made either to books or glass-makers. Briefly, it may be 
said that for special glasses, where covering of the metal is essential, 
when considerable time is occupied in complete fusion and mixture 
of the constituents, when they must be kept together long enough 
to combine, and where accurate regulation is required, the pot- 
furnace is more suitable. "When large quantities of less pure 
glass are required, maximum space and heating are to be utilized, 
and. time saved by continuous working (for pot-furnaces must 
cool down and be reheated, and pots fail and need renewing) the 
tank-furnace is better. The level of the metal is kept fairly con- 
stant, and therefore convenient for the withdrawal of gatherings, 
in a tank-furnace; while the glass left in the bottom of a pot 
frequently becomes "cordy" or "wavy" on blowing, and rarely 
is as good, or of the same composition and properties, as that 
already used from the pot. 



BEQTTIBEMENTB OF A. GOOD GTjASS-SAND. 39 



CHAPTER V. 

THE REQUIBEMEK-TS OF A. GOOD G-LASS-SAND. 

The sand hitherto used in this country for .all the best kinds of 
glass-work is that of Upper Oligocene age from Fontainebleau, 
near Paris. It is shipped from Rouen and delivered in Britain at a 
fairly cheap rate. Since the outbreak of war, manufacturers have 
found considerable difficulty in getting it through, owing to shortage 
of barges and labour, and the dislocation of trade. Enquiries 
were therefore made for suitable substitutes from the geological 
formations cropping out in Britain, with the results given later in 
this Memoir. 

, Characters of Fontainebleau Sand. As a glass-sand, that of 
Fontainebleau nearly approaches perfection *. If, therefore, w& 
look into its properties in some detail, we may hope to realize the 
desiderata of a first-class glass-sand, and know what to look for in 
any other deposits exploited for glass-purposes. 

(a) General Characters. To the unaided eye, the sand is a 
beautiful white, fine, even deposit. With a hand-lens the sand 
appears to be composed of water- clear quartz, and only here and 
there a few dark grains are to be seen. Unless the sand has been 
washed after its arrival at the works (and for all .special glasses 
for optical purposes and table-ware it is usually washed carefully), 
a little dirt and occasional specks of black coaly matter may be seen. 
Such impurities are, of course, adventitious, and obtained from 
trucks and barges in course of transit. The grains have no coating 
of white clayey matter, as many sands have, their white appearance 
being due to the ordinary reflection of light from irregular surf aces 
They are almost invisible under the microscope when mounted in 
media such as clove oil, Canada balsam, etc., the refractive indices- 
of which lie very near to that of quartz (Plate II. fig. 1). The 
grains are free from the pale yellowish or brownish coating of iron 
oxide so frequently seen in sand. 

(b) Chemical Composition. Chemical analyses (see Table VI.) 
show that the sand contains 99'65 to 99'97 per cent, of silica, and 
therefore must be composed almost entirely of pure quartz. Only 
a small quantity of iron oxide is present ; hence glass made from 
the sand is practically water-clear (provided, of course, no colouring 
compounds are added). The alumina percentage is very low, being 
probably accounted for by the rare grain or two of felspar seen, 
and by the few heavy minerals present. Lime and magnesia are 
practically absent. 

* The sand from Lippe, in Saxony, is slightly purer, but Fontainebleau 
sand being better known in t^i country, has been selected for description. _j 



40 



OP A GOOD GLASS-SAND. 



SiO, 
AL.03 
Pe a 3 
CaO 



Chemical Analysis of Fontainebleau Sand. 

1 Derby Glass Works. Barnaley Glass Works. 

99-80 per oent. 



99-67 
0-19 
0-002 
0-14 



MgO .................. none 

Loss on ignition ... 0*18 



0-13 
0-006 
traoe 
n. d. 
0-18 



Totals 100-182 



100-116 per oent. 



(c) Mineral Composition. Fontainebleau sand, like many other 
veiy pure quartzose sands, contains less than 0'02 per cent, of heavy 
minerals, which is below the average for all sands. In this heavy 
crop, of density >2'S, the minerals present are clean and fairly 
coarse in grain. They include 

magnetite, in irregular black grains ; 

zircon, in slender prismatic crystals ; 

rutile, an irregular foxy-red grains ; 

ilmenite, altering to lencoxene ; 

tourmaline, blue and brown, in somewbat rounded prismatic fragments ; 

ataurolite, in golden yellow angular grains ; 

andalusite, as small clear pleochroio grains ; 

mufloovite, in larger flakes ; 

kyanite, in almost rectangular well-cleaved fragments ; 

limnnite, etc. 

From the chemical composition of these detrital minerals it is 
seen that silica is present in some amount, and that small quan- 
tities of iron, aluminium, titanium, magnesium, zirconium, and 
boron occur. The proportion of heavy minerals in the sand is so 
smaJl, however, that even with the large bulk of sand used for the 
batch, the aggregate amount of impurities is slight. 

(d) Mechanical Composition. The evenness in grain of the 
sand (to the eye) has been commented upon, and mechanical 
analyses determined in elutriators like those described in Chapter III. 



Diams. "I 

in mm, J 


OS. 
>0-5 
&<1. 


MS. 
>0-25 
&<0-5. 


PS. 

>o-i 

&<0-25. 


B. 

>0-01 
&<0-1. 


c. 
<0-01. 


s. 

Total sand-grade: 
>0-1 & <1 mm. 


1 

2 


<o-i % 


70-6 % 
70-3 


26-6 % 
28-3 


2-8% 
0-6 


0-0% 
0-8 


97-2 % 
98-6 

















1. Obtained by the kindness of Mr. Frank Wood, Managing Director of 
Messrs. Wood Bros., Glass Manufacturers, Barnsley. 

2. Obtained by the kindness of Mr. 8. N. Jenkinson, Managing Director of 

the Edinburgh and Leith Gloss Co. Ltd., of Edinburgh. 

A suitable method of graphical expression is by means of a 
curve, as in Figs. 9, page 32, and 10, page 60. Practically no grains 



CHEMICAL COMPOSITION. 41 

occur with diameter above O6 mm., and very few are below O'l mm. 
diameter (see Plate III. fig. 1). 

(e) Shape of Grains. Lastly, as regards shape, Fontainebleau 
sand is made up of grains consistently subangular. To what extent 
the rapid and even melting of the batch depends upon the shape 
of the grains of sand is a disputed question, but it is clear that 
such a sand as that of Fontainebleau, the grains of which are all of 
similar shape, is preferable to one containing a mixture of angular, 
subangular, and rounded fragments. 

(f) .Economics. In addition to the recommendation afforded 
by chemical purity, evenness of grade, and suitability of size and 
shape, Fontainebleau sand can be transported cheaply and con- 
veniently to most British glass-making districts. This is due to 
the insular position of Britain, and to the fact that the sand can be 
directly shipped from Rouen, and without further handling may be 
discharged high up the estuaries which notch our industrial areas. 

Requirements of Q-lass-Sands. 

Up to the present time most manufacturers and writers have 
been inclined to emphasize .the importance of chemical analysis, and 
to demand a very high standard of purity in the sand. Experi- 
mental work earned out since the opening of the war has tended to 
indicate that fairly pure British sands can be used with success for 
much good flint-glass work, thus tending to destroy the fetish of 
"nothing but Fontainebleau." Indeed, a few of the managers 
who have studied the technique of their work place the question 
of the evenness of grain of their sands on an equality Avith, if not 
above, that of very high silica and very low iron-content. In the 
manufacture of glass other than that for optical purposes (where 
exceedingly pure sands are sometimes required) the mechanical 
analysis is of great importance. 

1. Chemical Composition. From the chemical point of view, 
sands for glass-making should have a very high silica- content, pre- 
ferably over 98 per cent., and for the best work over 99 ~5 per cent.*; 
they should have a low iron-content, for the best glass-work below 
O05 per cent. Iron is always present in the heavy detrital minerals, 
as magnetite, limonite, or ilmenite, or in the form of silicates, etc., 
but since the heavy crop in a suitable glass-sand is always less 
than 1 per cent., it is not the iron so present which determines 
the suitability or otherwise of the sand. Even such a very pure 
" sand as that from Fontainebleau contains a proportion of dense 
minerals, but its low iron-percentage is due to the absence of any 
coating of limonite (hydrated iron oxide) or hematite (Fe a O a ) upon 
the quartz-grains. This iron-staining in sands, which is the cause 

* See chemical analyses in Tables. In addition to these, Hohenbooka sand 
is said to contain 99'71 per cent., and sand from Nievelstein, in the Rhine 
Province, QS'Q 1 ? per cent, of silica. 



*^ BEQTJIBEMESTTS OF A GOOD UJjASS-SAElJ. 

of the rejection of a large number of English samples, usually exists 
on the outside of the quartz and felspar grains, but is sometimes- 
seen inside, due to subsequent growth of quartz after depositkm of 
the pellicle of iron oxide. Inclusions of ferruginous material also 
occur in quartz and felspar, having been caught up and enclosed 
at the time of their crystallization. 

The iron-percentage should therefore always be low, but a small 
amount present in the sand need not render it unsuitable, provided 
the mechanical analysis is satisfactory, for much good glass-work, 
such as lamp chimneys, globes, laboratory -ware, etc. The green 
or yellow colour due to iron may be corrected by the addition of 
decolorizers (including oxidizing agents or oxygen camel's) such as 
manganese dioxide, white arsenic (As a O a ), nickel oxide, selenium, 
etc. 

Glassy rocks, such as obsidian, tachylyte, etc., which are pro- 
duced by the rapid cooling of igneous magmas, similarly owe their 
dark green, black, or brown colour to the presence of compounds of 
iron, alumina, Urne, etc. Similar "black" or dark green bottle- 
glass may obviously be made from impure sands. 

In consequence of the demand for a high silica-percentage, the 
sands used are almost entirely composed of quartz-grains. The 
presence of felspar-grains in a glass-sand is desirable for many 
purposes, but, unfortunately, it generally means an increase in iron 
and other constituents. The usual method, therefore, of obtaining 
the required amount of alumina and alkalies is to add pure felspar,, 
alumina, and salts of potassium and sodium to the batch. Sands low 
in iron are for the greater part very free from other constituents 
also, _ rarely containing, except as' traces, substances other than 
alumina. To yield the proportion of alumina required for certain 
glasses, a sand consisting of 40 per cent, to 60 per cent, of felspar- 
would be required. Such sands, if they are to be free from iron 
oxide and certain other substances, are very rare, and indeed could 
only result from the denudation of such a rock as a very pure 
quartz-porphyry or a pegmatite, with no admixture from any other- 
source. In Chapter IV. (page 36) the Thuringian Forest sand, 
bearing 3*66 percent, of alumina, was mentioned as being especially 
suitable for the making of thermometer-glass. 

Calcareous sands are of frequent occurrence, but are to be 
avoided. The calcareous material is often sporadic in its distri- 
bution. The Fontainebleau deposit is well known to geologists 
for the beautiful steep rhombohedral crystals made up completely 
o sand-grams, just cemented by calcite into the crystal shape. 
The sand used for glass-work is selected free from this calcareous 
material, but occasionally the supplies received in Britain contain 
a few chalk-cemented balls. These are objected to when found, 
but usually all the consignments are similar in their purity and 
remarkably true to sample. Other impurities also tend to occur in 
calcareous sands ; and lime itself is an undesirable constituent ia 
sands used in the manufacture of certain kinds of glass 



MINERAL AND MECHANICAL COMPOSITION. 43 

2. Mineral Composition. The mineral composition is useful as 
giving an indication of the relative amount of heavy detritaL 
minerals present in the sand, and the quantity of quartz and 
felspar in the lighter crops. Sands with large crops of heavy 
minerals can only he used for rough bottle-glass. Indications of : 
the presence in quantity of minerals other than quartz are, of 
course, yielded by the chemical analysis. Mineral analysis is, how- 
ever, a shorter and less tedious process, and like the spectroscopic 
examination of sands, reveals the presence of small quantities of 
the less common elements. Naturally -panned sands namely, those 
in which the heavier minerals have been concentrated as a result of 
oscillation produced by currents of wind or water must be avoided,, 
even if, as in some cases, they are wlu'te and clean-looking. Iron 
minerals frequently make up a considerable bulk of a heavy residue. 
Sometimes, by the combined effects of wind-action and screening 
by vegetation (as in some of the Irish dune- and beach-sands), a 
kind of winnowing action takes place by which they may be purified 
locally from heavy minerals. Most of the British sands of this 
character are made up of mineral material derived from many 
sources, and while yielding interesting mineral assemblages (in- 
cluding micas in English, Scotch, and Irish samples, although 
Retgers states that these minerals do not occur in Dutch dune- 
sands) are, in spite of being washed free from some adherent 
limonite and clay, of little use except for green bottle-glass work. 

The presence or absence of certain minerals highly objectionable 
in glass-making may quickly be noted by mineral analysis. Zircon 
crystals ("ZrSiOJ, if present in quantity, are very undesirable on 
account of their highly refractory character. They remain un- 
digested in the " metal." Titanium minerals such as ilmenite 
(FeTiOJ, rubile (TiO.,) and its isorners, anatase and brookite (which 
are rarely abundant) are also detrimental to the making of good 
glass. Titanium is always an objectionable constituent of the 
" metal," and it so happens that ilmenite and rutile, like zircon, 
are among the most commonly occurring detrital minerals. 

3. Mechanical Composition (see page 21 for description of 
apparatus, etc.). Elutriation is carried out on the assumption 
that the sediment is composed entirely of quartz, or of minerals of 
the same density. Most sediments contain so small a percentage 
of heavier or lighter minerals, that the error introduced by them 
is less than that due to experimental causes. 

Mechanical analyses of glass-sands, including many from abroad 
which are successfully used in the trade, indicate that the sand 
should have at least 70 per cent., and, if possible, more than 
90 per cent., of one grade, and that this grade should be in most 
cases medium sand, i. e. with diameter between 0'25 and 0'5 mm. 
(O'Ol to 0'02 inch). Although a " medium " sand in t"he geological 
sense, it is a fine looking material to the eye. If the true " fine 
sand" grade, O'l to 0'25 mm. diameter, forms the bulk of the deposit, 



44 REQUIREMENTS OF A. GOOD GLASS-SAITD. 

.so much the better, but such sands are not abundant in the British 
Isles. A distribution of the bulk of the sand over these two grades 
is also not very objectionable, although glass-makers naturally 
prefer constancy of size. Grains over 1 ram. diameter in a sand 
reduce its value considerably, and it is best that none should have 
.a diameter greater than O5 mm. diameter. If the extra expense is 
not prohibitive, a pure and fairly well-graded sand may be sifted by 
screens to rid it of grains over 0'5 mm. diameter. Of the few sands 
used in glass-making, containing the coarse grade, we may mention 
ihat from Leighton Buzzard in Bedfordshire (Lower Greensand). 
The sand as supplied has been washed, and contains 24'6 per cent 
by weight of diameter between 0-5 and 1 mm., and 74 - 3 per cent, of 
diameter 0-25 to O5 mm. The latter grade is suitable and its per- 
centage is fairly high, but it would be desirable if the other 25 per 
cent, were of the next smaller, and not the next larger, grade, 
.as in the case of Fontainebleau sand, where the portion >O5inm.. 
diameter = O'l per cent, or less, >0'25 and <0 - 5 mm. = 7OG per 
cent., and >0'1 and <0'25 mm. = 26'6 per cent. 

If the " batch " is ground fine before being melted the question 
of grade-size in the sand is obviously not of such moment, and 
high percentage of silica and low percentage of iron are the 
desiderata. Leighton sand was used in this way by one firm making 
chemical glass-ware, but it is doubtful whether much advantage 
accrues from the grinding except in the case of the best glass- 
ware. The extra expense is considerable. 

As the Tables indicate, there are many British sands of which 
the mechanical analyses are similar to that of Fontainebleau 
sand. The regularity of grade of blown -sands in various other 
parts of the world has previously been commented upon, and the 
same holds true for British dune- and shore-sands. Altbmigh 
the evenness of these sands, due to selective transportation and 
deposition of material, renders them very suitable for glass-making, 
the colour, as previously remarked, shows the presence of too much 
iron and heavy mineral residues for the sands to be used for other 
than common bottle-glass. Dutch and Belgian sands imported into 
this country vary considerably in character. They are uniformly 
high in silica (some varieties containing pink quartz) and are 
used for other purposes, as well as glass-making, on account of 
their refractory properties. The colour and iron-content vary 
somewhat, but the grade-analysis, although variable, usually shows 
a high percentage (over 90) of the medium-sand grade. These 
are good all-round sands, and the nearest .English equivalent in 
mechanical composition is the Lower Greensand obtained from 
near King's Lynn, in West Norfolk (Sandringharn Sands). Many 
qualities of this sand are supplied, and the best has a colour and 
low iron-content equal to those of the best Belgian sand, as well as 
a high percentage (95 per cent.) of the desirable grade. Further 
notes upon the various qualities will be found under the remarks 
upon this source of supply. 

British sands with a high percentage of the grade of "fine sand" 



MECHANICAL COMPOSITION 1 . 45- 

include those of the uppermost Thanet Beds from the well-known 
Chaiiton pit in Kent, and the Kelloway Beds of Burythorpe, near 
Malton, Yorkshire. The fineness of their dominant grade and its. 
high percentage (nearly 70 per cent. diam. > O'l and < O25 mm.) 
are advantageous. 

In the Tables the cumulative percentage of all the sand-grader 
( > - 1 and < 1 mm. diameter) is given in a separate column (S)> 
This should approximate to 100 per cent, for glass-sands, and 
rarely be less than 95 per cent. The grade of diameter > O'Ol mm. 
and < O'l is best termed the silt-grade, but actually the coarser- . 
material of this grade is a superfine sand. It is theref ore sometimes 
desirable to estimate it in two portions : (a) superfine sand of diameter 
>0'05 mm., (Z) silt of diameter <0'05 mm. Certain deposits,, 
for example, are certainly sands, but contain a high percentage- 
of the grade >0'01 and <0'1 mm., the grains composing which 
are mostly above 0*05 mm. diameter. Such are the sands of the 
Inferior Oolite from Bridport, Midford, Yeovil, the Cotteswolds, 
etc., which show a remarkable uniformity of grade over a large 
area. 

These Inferior Oolite Sands are unfortunately yellow in colour,, 
contain much iron oxide, and heavy crops of dense minerals. They 
are occasionally calcareous, but clear rapidly to fine white micaceous 
sands on warming with dilute acid. Their use for glass purposes 
is therefore at present ruled out. Sands of this extremely fine 
grade are rare in the British Isles. 

Sands to be xisecl for glass-making should not contain much of 
the silt-grade. The clay-grade, of diameter < O'Ol mm., certainly 
should be absent. The percentages shown in the tables were 
estimated by difference (see page 23). The figures in this column, 
therefore, include hygroscopic water (some of the samples were 
air-dried at first, and all the grades were dried at 100 C. before 
weighing), dust accumulated by exposure and during transit of the 
sand, the limonitic coating on grains in some cases, and films of 
soluble or other salts (e. g. sea-salts in the dune- and shore-sands).. 
Probably this grade is practically absent in most cases where it is 
recorded as less than 0'5 per cent. 

Such sands as those of Triassic age from Wbrksop in Nottingham- 
shire, and Spital in Cheshire, actually contain clayey and silty 
material (including kaolin). Some of the clayey and dusty matter 
coats the grains of quartz and felspar. The Tables indicate that, 
although they are fairly clean sands, they are not sufficiently 
well-graded to be suitable for the making of other than common 
glass. 

Mechanical analyses of American and Danish glass-sands are- 
appended for comparison (see pages 168, 169, 170). 

The use of pot- or tank-furnaces has an important bearing on the- 
grade of the sand used for the batch. When a poorly-graded sand, 
containing much fine powdery silica, is used in the batch for a 
tank-furnace, considerable loss due to "blowing-out" results. The 
other constituents such as compounds of the alkalies, which may 



46 BEQTJIBBMBNTS OF A GOOD GLASS-SAND. 

be in the form of fine powder, melt more rapidly, and so are not 
lost*. A con siderably higher temperature must be attained before 
silica fuses ; fine material is therefore earned away by the blast of 
gas and air before it melts. Not only does a real loss in bulk 
thus occur, but the resulting composition of the batch is changed. 
When melting takes place in pots, this loss by blowing-out is 
obviated. Silica in a fine state of division in a sand is also open to 
objection on other grounds. Air-bubbles entangled in the fine 
material are introduced into the "metal" from whicli they are re- 
moved only with great difficulty. The fine particles melt before the 
coarser ones, and the resulting metal sinks to the bottom. The 
density of the molten material thus formed is not constant, and 
varies as the pot is depleted of its contents. If coarse grains are 
present, the batch takes longer to melt, or these remain as undigested 
or partly digested lumps in the glass (" seeds '" or " stones "). The 
results, therefore, of using non-graded sands are unsatisfactory. 
'The value of such a sand as that of Fontainebleau lies in the way 
in which the whole of the batch containing it passes smoothly into 
the molten condition at almost the same moment. Angularity or 
subangularity of the grains may contribute to rapid melting. 

No arrangements for stirring the metal exist in most furnaces. 
The result of using imperfectly-graded sands is therefore the pro- 
duction of "metal" of unequal composition, texture, and density, 
with consequent trouble in working. Clayey materials also tend to 
cloud the glass, and kaolin itself is highly refractory and formerly 
rendered unsuitable a sand containing it. 

The statement in an American publication (U. S. G-. S. Bull. 
286, p. 454) that sand of diameter less than -fa inch bums out 
in the batch, giving less glass, is not borne out by British and 
Continental practice, where so much of the sand used is of diameter 
less than -^ inch. Sand of 20 to 50-mesh, advocated by American 
writers, appears to be coarser than British glass-manufacturers 
prefer to use. 

4. Angularity of Glass-Sands. The grains composing the 
sands in general use for glass -making in Britain are either angular 
-or subangular in character. Sands containing rounded grains are 
not popular with some glass-manufacturers indeed, angularity is 
preferred in England. The most obvious explanation of the pre- 
ference for angularity seems to be that the grains fuse more rapidly, 
the process beginning at the corners and edges, the surface-area 
being greater, volume for volume, than that of rounded grains. 
.Some 01 the Belgian sands are highly angular, having a sharp feel. 
Rapid melting is desirable and saves much time and trouble ; thus 
both furnaces and sands are called upon to contribute towards this 
end. 

* In many works it is found that n-IWH dust and not silica is carried over 
into the flues and chokes them. Careful filling of the batch does much to 
prevent the loss of fine material, but rapidity of filling is essential. Damping 
-the batch has also been recommended. 



VARIATION ACCORDING TO GLASS PRODUCED. 47 

Sands composed of rounded grains appear to be successfully used 
for glass-making in America (see Plate V. fig. 2) *. 

In certain works where table- ware and bottles made of flint- 
glass have names and marks etched upon them, by sand-blast action, 
the sand used in the blast as the abrasive is the same Fontainebleau, 
Belgian, Aylesbury, or Lynn sand as that utilized in making the 
glass. Besides its marked angularity (so that its cutting power may 
be as great as possible), a sand for etching should be hard and 
tough. For common purposes a highly siliceous, i. e. quartzose, 
sand is suitable. It must' be perfectly dry and of even grade (not too 
coarse), in order that it may pass freely through the funnels, etc., 
and not clog the jets and stencil upon the sudden release of 
pressure. If water-vapour is present the adiabatic expansion and 
fall of temperature results in its condensation, and clogging takes 
place. Some sands used for grinding plate-glass are worked at 
Leighton Buzzard ; others have been dredged from the bed of the 
River Mersey. 

Variation according to the Icinds of G-lass produced. 
For the commonest glass (bottle- ware, etc.) the mechanical 
analysis is of prime importance. The sand must be well-graded 
and composed of suitably-sized grains. Greater latitude in chemical 
composition is permissible than with better-class glasses. The 
silica-percentage should still be fairly high, but low iron-content is 
not so essential: it may vaiy up to 1 per cent, (as Fe 2 OJ. The 
presence of small quantities of titanium, aluminium, calcium, and 
alkalies is but slightly harmful. 

For ah" medium-class glass-ware, including the best bottles, 
chemical ware, globes, chimneys, pressed-ware, etc., both chemical 
and mechanical analyses are of great importance. High silica- 
content (and for much laboratory-ware, etc., high alumina) and 
low iron-content are demanded. Other constituents, if present at 
all, should be in minimum quantity. Good grading is extremely 
desirable, and the size of grain should not fall outside the limits of 
0*5 and O'l mm. diameter. 

For high-class glass-ware such as optical glass, table-glass (which 
is afterwards "cut"), and other special glasses, the chemical 
composition is of prime importance, and the mechanical analysis 
often, but not always, takes a secondary rank. In the famous 
cut-glass table-ware industry of the Stourbridge district, the batch 
is not at the present time ground fine, neither do arrangements 
exist for stirring the metal ; in consequence the grade, as well as 
the chemical composition, must be of a high standard. For the 
other ware mentioned, a high percentage of silica (and at times, 
alumina) is demanded, and little or no iron should be present. 
As the batch is sometimes pulverized and as stirring is occasionally 
adopted, the " metal " being allowed to remain molten for a long 

* United States Geological Survey, Bull. 285, 1906, page 454. See also 
Mineral EesonroeB, ' Sand and Gravel' for 1915 and earlier years. 



48 BEQTJIBEMENTS OF A GOOD GLA.SS-SA1TD. 

period, crashed rocks and quartz, as well as poorly-graded sands, 
might be utilized. 

Summary : The Ideal Glass-Sand. 

A perfect " sand " in the geological sense, that is one composed 
entirely of grains belonging to one grade, which should not be a 
coarse one, yields the best material for glass-making, provided that 
the chemical composition is suitable. . As a general rule, for all 
kinds of glass-work the iron oxide (Fe a O n ) percentage should be 
low, always under 1 per cent., the higher limit being permissible 
only for glass for the cheapest class of bottles. As already stated, 
the sand used for the best varieties of glass, such as optical glass, 
best flint- and sheet-glass, best Bohemian glass, " crystal " table- 
ware, etc., should contain at the most only a few hundredths 
('02 to '08) per cent, of iron oxide. Alumina, magnesia, and 
lime may be'present in sands in the form of felspars, ferromaguesian 
and lime-bearing minerals, and calcareous cement, but are required 
only for certain glasses. These bases are very refractoiy and 
lengthen the time taken for melting. Sands free from them are 
preferable, both because the bases are required only for refractory 
glasses, and then must be added in larger quantities, and because 
the presence of minerals containing them in sand usually means 
also the presence of a prohibitive quantity of iron. The specific 
properties of optical glass are altered by the presence of such 
impurities in the sand. 

It is found desirable, therefore, to rely upon the sand only as a 
source of pure silica, and to add other bases for the purpose of 
making the various kinds of gkss desired. 

The ideal sand for the best glass-making is one with 100 per 
cent, silica and composed of angular grains all of the same size, and 
of the grade known as medium or fine sand. Such a perfect sand 
has not at present been discovered, but the ideal is approached by 
a few sands, including those of Fontainebleau in France (99 - 7 
per cent, silica), Lippe in Germany (99-8 per cent, silica), and 
Berkeley Springs in the U.S.A. (99-65 per cent, silica). Sands 
from Lippe and Berkeley Springs are described in Chapter XT. 



BBITISH SANDS SUITABLE FOB GLASS-MAKING. -19 



CHAPTEK VI. 
BEITISH SANDS SUITABLE FOB G-LASS-MAKIN&. 

The Tables of chemical and mechanical analyses on pages 154 to 
170 give an indication, in the light of what has heen said before, as 
to how far British sands may be used to replace those imported from 
abroad. In the first place, there does not appear to exist, anywhere 
in the British Isles, a sand so suitable, from all points of view, for 
the making of the best kinds of glass, as those from Lippe and 
Fontainebleau. The best sands from Aylesbury in Buckinghamshire 
and from Fail-light in Sussex are equal to Fontainebleau sand, and the 
sands from Huttons Ambo and Burythorpe in Yorkshire, and other 
places, are certainly as good as much of the Belgian sand imported. 
Lynn sand, at its best, is also equal to much of the Belgian 
material, and is superior to some of the Dutch sand. The same- 
remarks apply to Grodstone and Reigate sands (Lower Greensand, 
Surrey), but the deposits are irregular. A large number of British 
sands, especially dune- and shore-sands, are less pure, but are well 
suited to the making of common bottle-glass. Mechanical analyses 
of some representative examples of these are given in the Tables, 
on page 165. 

The writer is unable to agree with Dr. W. Kosenhain, who, in 
the Cantor Lectures before the lioyal Society of Arts in 1915, 
said : " In this respect [_i. e., suitability of sands] glass-makers in 
England are unfavourably situated, since there are at present no 
very suitable sands available in this country. Whether exhaustive 
search might lead to the discovery of a suitable deposit is doubtful, 
because a large number of firms have already sought for good 
glass-making sands, and find it difficult to supply even the require- 
ments for ordinary window (sheet) glass." Necessity, exploration,, 
and experience under war-conditions has resulted in the use of 
large quantities of British sands for all kinds of glass of better 
quality than window-glass. The statement is also an exagge- 
ration of the difficulties which existed before 1914. 

Analyses and notes upon some important foreign glass-sands are- 
given in Chapter XI. for purposes of comparison. A few mechanical 
analyses are graphically expressed in the curves of Figs. 10 and 11 
(page 50). 

No attempt has been made in the following pages to treat 
exhaustively British resources of common sands suitable for dark 
bottle-making. Such supplies are abundant and ubiquitous, and 
can be found at no great distance from the works. 

The descriptions are given under the heads : A. Purely siliceous- 



50 



BRITISH SANDS SUITABLE FOR Q'LA.SB-'MA.TS.TSQ. 



Fig. 10. Mechanical Analyses of Glass- Sands : Foreign. 



90 . 

BO . 

I 

T 70 4 

jBO - 

I 50- 

a 

I 40 

JO 

| 30 
u 

t 20 
10 



./ /./ //" 

^p / u ;/ 
*/ ^// 

fe/ /A' 




i-o 



0-5 0-25 

Grade Sizes (diameter in Millimetres} 



Fig. 1.1 . Mechanical Analyses of Glass-Sands : British. 



90 . 

80. 

-5,70. 

1 

60. 
I 50. 

..I 40 . 

1 

| 30 . 
o 

f 
1 20 . 

10 



fil 
' 




T 



1-0 



0-5 0-25 

Grade Sizes (diameter in Millimetre*) 



0-1 



AYLESBTTBY SAND. 51 

materials, including () sands, (J) crushed rocks; B. Siliceous 
deposits caiiying () alumina, and (b~) alumina and potash 

A. PUBELY SILICEOUS DEPOSITS 

() SANDS. 
" Aylesbury " Sand. 

Worked by The Aylesbury Sand Company. Manager, Mr. J. 
Arnold (Offices, 32 St. Paul's Eoad, Oamden Town, N.W. 1). 
Maps. Geological : Old Series, 1-inch, Sheet 46 S.W. 

6-inch, Buckinghamshire, Sheet 32 N. W. 
Situation. Lot. 51 48' 22", Long. 52' 5" W. 
The quarries occur at Stone, three miles west of Aylesbury. 
The sand is also exposed in the " Windmill " pit, but is not worked 
there to any extent. 

Formation . Lower Greensand. 

Description. White seams of pure sand, suitable for flint-glass 
work, extend to a depth of about eighteen feet. Working is then 
stopped by water. Peaty and ferruginous bands occur, and since 
the seams of white sand are not very thick (four to six feet) or 
persistent, working is rather difficult. It is not easy to ensure that 
successive consignments conform to the highest standard of purity 
met with, and variability is abhorred by glass-makers. The 
whiteness and purity may be connected with the peaty bands. 
The colour is good, the best Aylesbury sand being better than 
Belgian, and selected samples being equal to Foutainebleau sand. 
Washing does not improve the colour of the best sand to any 
extent, but a second-quality sand, washed free from limonitic and 
clayey pellets (in rotary washing-plant), is also supplied. The 
latter sand is pale grey, but reddens slightly on burning, whereas the 
former shows little or no change. The chemical composition is as 
follows : 

Best Washed sand Bulk 
Band. as delivered, sample. 

SiO 99-80 99-39 98-76 per cent. 

AlA 0-32 0-48 0-37 

Fe 2 3 0-03 0-02 0-03 

CaO' n.d. n.d. 0-17 

MgO n.d. n.d. 0-10 

Na.,0 n. d. n. d. none 

K.6 n.d. n.d. 0-04 

Loss on ignition 0'22 0-18 0"33 

Totals 100-37 100-02 99-80 per cent. 

The evenness of grade is a marked feature, the sand in this 
respect very closely resembling Fontainebleau (see Plate III. 
figs. 1 & 3). The mechanical composition is as follows : 



Sections marked thus deal with sands and rooks which are also of use 
refractory materials. 

E2 



62 BRITISH SANDS SUITABLE FOR GLASS-MAKING. 

>0'5 mm., few grains only; >0'25 & <0'5, 78-3 % ; >01 & <0'25, 15'0 % - 
>0'01 & <0-1, 6-8 % ; <0-01, 0-9 %. Total sand-grade, >0'1 mm., 
93-3 %. 

PCS MS JFS _s_ _o S_ ~j 

Ltr.' 78-3' 15-0' 5'8' 0-9 ; 93-3' J 

The detritnl mineral suite is very characteristic of the Lower 
Greensand throughout England. Heavy minerals are fairly 
abundant (0'2 to 0-3 mm. diameter), and the residue consists 
almost entirely of coarse, angular kyanite, staurolite, and brown 
and blue tourmaline, together with iron ores (magnetite, limonite, 
and altered ilmenite), zircon, rutile, etc. 

The sands, after being carted to Hartwell Siding near Aylesbury 
Station (GK C. Railway), were put on trucks, before the war, at 
7s. Qd. per ton. At the time of writing the price is 10s. This is 
rather high, and freight charges increase it to about 15s. or 17s. Qd. 
by the time it reaches a glass-making district as far distant as 
London or Yorkshire. 

The estimated quantity available in the area is two million 
tons *. 

Sands from Fairlight and Hastings. 

(1) FAIKLIQHT. 

Worked occasionally for sand, Milward Estate (Agent : Mr. G. 
E. Barr, 23 Havelock Rd., Hastings). 

3fapts. Geological : Old Series, 1-inch, Sheet 5. 
6-inch, Sussex, Sheet 58 S.E. 

Situation, Lett. 50 52' 30", Long. 38' 36" E. 

The pit is situated by the roadside, close to, and immediately to 
the south of, Fail-light Church, east of Hastings. 

Formation. Ashdown Sands (Wealden). 

Description. The bed of snow-white sand occurs at the base of 
the Ashdown Sands and immediately above the Fail-light Clays, 
of which a splendid succession is exposed in the cliffs below the 
Church. G-lass-sands were recorded as having been worked at 
Hastings long ago f ; they were doubtless sands like those exposed 
in this pit, and in that at Bulverhyth described below. The 
association of lignites with the Ashdown and Tunbridge Wells 
Sands has been recorded by Topley J and others, and the reducing 
action of the vegetable matter probably accounts for the freedom 
from ferruginous compounds. Fairlight Church stands towards 
the eastern end of a strong sandstone ridge overlooking Hastings. 
For two or three miles this ridge has, as its backbone, the white 
Ashdown Sands which are mentioned above. In an old quarry 

* In eaoli case the estimate of the resources IB by the writer, and is to be 
taken as well -within the upper limit. 

f Mineral Statistics : Memoir Geol. Survey, 1860, p. 375. 

t W. Topley, " The Geology of the Weald," Mem. Geol. Surrey, 1875, 
page 395 ; Ashdown Sands, pages 59, 80 ; Tunbridge Wells Sands, pages 78, 
85, etc. 



FAIRLTQHT AND lIASi'INGS SANDS. 53 

about a quarter of a mile west of the Church, a wall of about 
twelve feet of white sandstone, not bottomed, is shown over about 
a hundred yards of quarry face. Water stands in the quarry. 
The deposit is well jointed and bedded and easily workable. Only 
three to six feet of valueless overburden occur above the white sands 
in the Church pit. The beds jdeld a firm solid face, many of the 
joints being superficially dirt-stained. A sample, which is almost 
as pure in colour as Fontainebleau sand, burned up slightly pink. 
Its chemical composition is as follows : 

SiO., 99-47 per cent. 

Al,0. t 0-24 

Fe~O 3 0-002 

CaO 0-29 

MgO trace 

Loss on ignition 0-20 



Total 100-202 per cent. 

The high percentage of silica and low percentage of iron are 
noteworthy. This sample was not intentionally selected, but 
happened to be very low in iron. Another sample from the same 
bed contained 0'016 per cent, of iron oxide. 

The mechanical analysis shows : 

>0-5 mm., none; >0'25 & <0'5, 83'7 % ; >0'1 & <0'25, 16- 1 % ; >0'01 & 
<0-1, 0-1 % ; <0-01, 0-1 %. Total sand-gi-ade, >0-1 mm., 99'8 %. 

cf incj ,-. A cj 

H J? (3 S C B 

SS 7 ?' 16 7 !' (FT* (KP OJRT. 

Washing would doubtless improve the deposit both chemically 
and mechanically. 

The mineral composition indicates the presence of a few stable 
heavy detrital minerals in very small quantity, the proportion of 
density greater than 2 - 8 being only O'Ol per cent. The heavy 
residue is rather fine in grain, and the assemblage of minerals 
uninteresting. All the readily decomposable compounds have been 
eliminated before or since deposition. A little magnetite occurs, 
and limonite in small quantity is seen, llmenite is abundant 
(0'2 mm. diameter), but practically always altered to leucoxene. 
Brown tourmaline (0'15 mm.) is plentiful, and zircon (0-1 mm.), 
reddish rutile (O'l mm.), and muscovite (flakes 0*2 mm. diameter) 
occur. 

The most serious consideration is that of transport. A good 
road links the pit to Hastings, the Station (L. B. & S. C. and 
S. E. & C. Railways) and quay being four miles distant. The road 
is, however, downhill all the way, and motor-traction should be 
economically possible. The sand might then be shipped at 
Hastings. An alternative suggestion is that of taking the sand 
eastwards down to Cliff-End, near Winchelsea, and shipping it 
i'rom there. The nearest station to Fairlight is actually Ore 
(three miles), but it is badly situated in a hollow with a steep 



64 BUIXISH SANDS SUITABLE FOE GLASS-WAKING. 

gradient from ,the pit. The proximity of the London market and 
the possibility of water-transport to an even greater distance are- 
noteworthy. 

The available resources are over fifteen million tons. 



(2) BULTEEIIYTH, WEST Off HASTINGS. 

Worked occasionally for sand, Filsham Estate (Agent : Mr. T. 
W. Ellworthy, 81 London Ed., St. Leonards). 

JUiaps. Geological: Old Series, 1-inch, Sheet 5. 
6-inch, Sussex, Sheet 71 N.W. 

Situation. Lot. 50 51' 0", Long. 32' 18" E. 

The pit lies by the side of and north of the main road from 
St. Leonards to Bexhill. It is situated half a mile west-south- 
west of St. Leonards (West Marina) Station (L. B. & S. C. 
Bailway). 

Formation. Ashdown Sands (Wealden). 

Description. The great thickness of overburden (about 3D feet), 
consisting of brown sands, silts, and clays, renders doubtful the 
profitable working of the few feet of white sands at the base. The 
strata dip to the north into the rising ground, so that shallow 
excavations farther northward are unlikely to reach the bed. 
The ground falls towards the west, and, on the opposite side of the 
small lane which runs northward by the western end of the pit, the 
glass-sands crop out at the surface. Although they do not appear 
to be so pure here, improvement might be seen as they are worked 
inwards. The white sand is similar in chemical and mechanical 
composition to that at Eairlight described above. The iron-content 
is 0'04 per cent., and the grade-analysis is as follows : 

>0-5 & <1 mm., 0-8 % ; >0'25 & <0-5, 77'9 % ; >0'1 & <0'25, 20-3 % ; 
>0-01 & <0-1, 0-5 % ; <0-01, 0'5 %. Total sand-grade, >(KL mm., 
99-0%. 

res MS jrs _a_ _. s ~i 

L.O-8' 77-9' 20-3' 0-5' OV 99-0'J 

The mineral composition is also similar to that of the sand from 
Fairlight, but the heavy crop is distinctly coarser in grain. The 
most common rninerals, in order of abundance, are ilmenite, altering 
to leucoxene, grey-brown tourmaline (O'l mm. diameter), foxy-red 
and, less commonly, yellow rutile (O'l to 0-25 mm.), zircon in 
pinkish, purple, brown, and zoned crystals (O'l to 0'25 mm.), and 
uruscovite flakes, the average diameter of Avhich is about twee that 
of the other grams. 

The pit is favourably situated for transport, being at the side of 
a main road, and only a quarter of a mile from West St. Leonards 
Station (S. E. & C. .Railway). Small quantities of the white sand 
have been carted to the station for despatch. 

The available resources are under a million tons. 



ASHTTRSTWOOD SAMT>. 55 



Sand from Ashurstwood, near East Q-rinstead. 

Not at present being worked. 

Owner. Mr. A. H. Hastie, 66 Lincoln's Inn Fields, W.C. 2. 

Maps. Q-eological : Old Series, 1-inch, Sheet 6. 
(3-inch, Sussex, Sheet 5 S.W. 

Situation. Lat. 61 6' 60", Long. 1' 15" W. 

Large excavations at Ashurstwood, particularly in Cherry Garden, 
north and north-west of the Church, south-east of East Grinstead, 
yield evidence of extensive early working. 

formation. Tunbridge Wells Sands (Wealden). 

Description. The sand stands up in firm faces and blocks, 
sufficiently so to be described as a soft sandstone. The combined 
effect of weathering and excavation is to yield picturesque " rocks," 
the creamy-colour of the sand being subdued upon, the weathered 
surfaces. A considerable thickness is indicated. Some of the 
seams are ferruginous, and washing would doubtless improve 
the whole deposit. 

Samples of the sand, creamy- white in colour, turn browner on 
burning. The chemical composition is as follows : 

Si0 2 98-77 per oent. 

Al,0 3 0-73 

Fe 2 3 0-01 

CaO 0-14 

MgO trace 

Loss on ignition 0'43 

Total 100-08 per oent. 

The sand is small in grain, and the mechanical analysis 
indicates : 

>0-5 mm., a few grains only; >0-25 & <0'5, 9-8 % ; >0'1 & < 0-25, 85'5 % - f 
>0'01 & <0-1, 2-0 % ; <0-01, 2-7 %. Total sand-grade, >0'1 mm., 
95-3 %. 



[-OS MS JTS _s_ o . S "I 
|_tr. J 9-8' 85-5' 2-0 1 2-7' 95-3' J 



The heavy residue is abundant and fine-grained, amounting to- 
O24 per cent. It consists largely of zircon, yellow and foxy-red 
rutile, ilmenite, and tourmaline of about 0'05 mm. diameter. 
Although the crop is abundant, the mineral assemblage is not 
very interesting. Muscovite (flakes O f 5 to 0'6 mm. diam.), 
glauconite, and yellow anatase also occur. 

The pits are situated about two miles from East Grinstead 
Station and a mile and a half from Forest Row (L. B. & S. C. 
Railway). There is a good road connecting them. Road- traction 
to London, about thirty miles distant, might also be possible. 

The available resources are over fifteen million tons. 



56 BEITISH SANDS SUITABLE FOB GLASS -MAKING-. 

"Lynn." Sand. 

(1) Worked by Messrs. Joseph Boam, Ltd. (Offices, Silver 
Street, Leicester). (See Plate VI., and also Plate IV. fig. 6.) 

Maps. Geological : Old Series, 1-inch, Sheet 66. 
6-inch, Norfolk, Sheet 33 S.E. 

Situation. Lat. 52 44' to 52 45', Long. 28' to 29' E. 

The sand is worked over an extensive area at Middleton and 
G-ayton, three miles east of King's Lynn, and numerous scattered 
quarries occur. 

formation. Sandringharn Sands (Lower Greensand). 

Description. The deposit is fairly persistent and thick, so that 
large supplies of sand running true to sample can he supplied. 
Little variation occurs in successive consignments. The sand is 
won for foundry- work, glass-making, building-purposes, etc. The 
red sands are used for the last-named purpose and also for the 
making of black-bottle glass. In considering the sands suitable for 
general glass-making, it is to be noted that the colour of the best 
Lynn sand is equal to that of the Belgian, but most of the sand is 
rather darker, three qualities, besides a washed and a double-washed 
sand being supplied. Rotary washing-plant is employed. The 
washed sand has a pale grey to brown colour. The iron-content is 
rather higher than that of Aylesbury sand, and on burning there 
is a marked change to redder or greyer tints. The chemical 
composition of the best sand is as follows : 

SiO, 99'23 per cent. 

AlA -50 

Fe,0' -04 

CaO' -11 

MgO -02 

Loss on ignition . , . '25 

Total 100-24 per cent. 

Note. A duplicate determination of the silica and also of the alumina 
carried out as a control gave the figures 99'20 % and 0'56 % , respectively. 

In mechanical composition the sand is seen to be well-graded, 
but rather coarser than either Aylesbury or Fontainebleau sand. 
The curve representing its composition in Fig. 11, page 50, is there- 
fore sympathetic with, but to the left of, those for Aylesbury, etc., 
sands. Typical analyses yield the following results : 

>0'5 & < 1 mm., none ; > 0'25 & < 0'5, 94'8 % ; > 0-1 & < 0'25, 4'9 % ; 
> 0-01 &<0'1, 0-2 %; <0-01, O'l %. Total sand-grade, >0'l&<lmm., 
99-7 %. 



["MS FS _s_ o _S I 
|_94-8' 4-9' 0-2' 6 V 1 ; 99'7'J 



From the point of view of glass-making, the remarkably good 
grading of the sand calls for special note. Although not so low 
in iron -content as some other British sands, it is certainly the 



LYNN SAND. 57 

most even in grain, and for that reason has heen preferred hy 
certain glass-manufacturers on account of its rapid melting. 
These remarks apply particularly to the sand from the pits near 
Middleton Station (G. E. Railway). This sand is washed to remove 
clayey and ferruginous matter, and, a new washing-apparatus 
(Rikof's pattern) has recently heen installed (see page 122 and 
Plate VII.). 

The sands "become less pure and more felspathic in the area near 
Gayton Road Station (Midland & Q-. N. Joint Railway). They 
are worked to a large extent for pale bottle-making, and are also 
of considerahle use for furnace-hearths. A chemical analysis of a 
sample of one of these sands is as follows : 

SiO a 97-34 per cent. 

11.03 1-34 

Ti<X trace- 

Pe 2 a 0-19 

CaO 0-09 

MgO trace 

K.,0 0-37 

Na.jO trace 

Loss on ignition 0'76 



Total 100-09 per cent. 

The mechanical analysis of the same sample indicates : 

>0-5 & <1 mm., 0-5 % ; >0'25 & <0'5, 95'1 % ; >0'1 & <0'25, 2-7 % ; 
>0-01 & <0-1, 0-8 %; <0-01, 0-9 %. Total sand-grade, >0'1 mm., 
98-3 % . 



PCS MS FS _s_ o S "1 
LO-5' 95-1' 2-7' 0-8' 0-9 ' 98'3'j 



Greenish seams of glauconitic material are not uncommon, hut 
as the glauconite (silicate of iron, aluminium and potash) is usually 
present as a coating to the grains of quartz, washing improves the 
sand considerably. 

The mineral composition indicates rather more felspar than in 
the other Greensand deposits discussed (note A1 2 3 percentage in 
chemical .analyses). The heavy detrital mineral assemblage is 
similar to that of the Lower Greensand generally, but, in addition, 
occasional garnets are found. 

The residue is a coarse one, the grains averaging 0'2 mm. 
diameter. The sand is extensively used for general glass-work, 
including window- and plate-glass, laboratory-ware, incandescent- 
lamp globes, chimneys, white and coloured bottles, etc. It has the 
great advantage of being cheap. 

The prices of the sands put upon the market are as follows : 
Brown Sand 3s. Qd. per ton, Unwashed White Sand 3s. 9d. per ton, 
Washed Sand 5s. Qd. per ton, Double-washed Sand 6s. per ton, 
Specially Selected and Double-washed Sand 8s. per ton, F.O.R. at 
Middleton Station (G. E. Railway) or Gayton. Road Station (Mid- 
land & G.N. Joint Railway). 



T>8 BEITISH BANDS SUITABLE FOE 

The washed sand is from the Middleton area, and the unwashed 
from near Gayton Eoad Station, but further washing is being 
contemplated. 

(2) Worked by Messrs. Gay & Wilson (Managing Partner, 
Mr. G. W. Smart). , 

Maps. Geological : Old Series, 1-inch, Sheet 65. 
6-inch Norfolk, Sheet 33 N.E. 

Situation. Lat. 52 46' 0", Long. 29' 0" E. 

Formation. Sandringham Sands (Lower Greensand). 

Description. The quarries occur immediately north-west of 
Bawsey Signal Box, about a mile north-east of Gayton Eoad Station 
(M. &G. N. Joint Eailway). The description given above applies 
equally well to these deposits, except that the sand is on the whole 
rather finer in grain and contains more iron (O16 per cent.). The 
results of mechanical analysis are given in the Tables on page 163. 
The pits reveal a thirty-foot wall of sand (at times approaching 
forty feet where excavations have been made in the floor of the 
pits), in places rather regular in quality, capped by Glacial Drift, 
which occasionally forms pockets. 

The sand is used to a considerable extent in the Yorkshire district 
for bottle-making, and also in the manufacture of soap. It is put 
on truck at Bawsey siding, Gayton Koad Station, at from 2s. 2d* 
to 3s. per ton, a better quality also being selected when desired 
and supplied at a correspondingly higher price. 

The available resources in the Lynn area are at least three- 
hundred million tons. 

"Leighton Buzzard" Sand. 

Worked by (1) Mr. Joseph Arnold, (2) Mr. George Garside, 
(3) Mr.. Gregory Harris. 

Maps. Geological : Old Series, 1-inch, Sheet 46 N.W. 
6-inch, Bedfordshire, Sheet 28 N.E. 

Situation. Lat. 51 56' 15" to 51 57' 10", Lona. 38' 20' ' 
to 39' 10" W. J 

The sand is worked over a large area north and north-east 
or Leighton Buzzard. Numerous quarries and old workings occur 
(Mile Tree, Shenley Hill, Stone Lane, Chance's Quarry, etc.). 

Formation. Lower Greensand. 

Description. The deposits are worked for a variety of pur- 
poses, glass-making being subordinate. 

Both chemical and mechanical compositions vary considerably. 
The coarse sands are supplied for water-filtration plant, connrete- 
making, grinding, etc. The highly ferruginous sand is used for 
building, and most of the pale-coloured medium-grained sands are 
worked and washed by a rotary method for foundry purposes, parti- 
cularly in connexion with steel-casting. This is on account of the- 



LEIGHTON BUZZARD SAND. 59 

high silica-percentage, there being very little felspar. For the 
greater part the sands are neither so pure and free from iron nor of 
so fine a grade as those of Aylesbury ; they are therefore not so well 
suited for good glass. They are used for the making of pressed 
gkss and laboratory-ware. The iron-staining is patchy in its 
occurrence, and the pale sands are thus impersistent. The whitish 
sands are again associated with peaty bands. 

The chemical composition of some of the samples of glass-sands 
is as follows : 

(1) (2) (3) (4) 

SiO 99-05 99-59 96-77 99-58 per cent. 

A1 2 6 3 0-23 0-25 1-77 0-27 

Fe a 3 0-14 0-21 0-27 0-03 

CaO 0-31 n.d. 0'15 0'22 

MgO 0-08 n.d. 0-03 none 

KjO none none 0-60 none 

Na a O none none 0'02 none 

Loss on ignition ... 0-81 0-27 0-63 0-13 ' 



Totals 100-12 100-32 100-24 100-23 per cent. 

(1) Arnold's pita, washed. 

(2) unwashed. 
(3j a fine grade. 
(4) Garaide's pit. 

For the most part, the sands are coarse, passing into line quartzose 
and cherty gravels. The latter are screened and used for abrasive 
purposes, including the grinding of plate-glass. Seams of fine 
white and grey sand occur, but are not common. 

The whitish and pale yellow sands supplied for glass-making are 
rather coarser than manufacturers like. A typical mechanical 
analysis is as follows : 

> 0-5 & <1 mm., 24-6 % ; >0'25 & <0'5, 74'3 % ; >0'l & <0'25, 1-0 % ; 
>0-01 &, < 0-1, less than 0-1 %. Total sand-grade, >0'1& <lmm.,99-9 %. 

r_CS_ MB FS _s_ S ~| 
|_24-6' 74-3' 1-0' 0-1 ; 99 '9' J 

The mineral composition is like that of Lower Greensand deposits 
generally. The description of the mineral assemblage of Aylesbury 
sand applies here. 

The sand is put on boat upon the Grand Junction Canal, or on 
truck at Leighton Buzzard, at 6s. per ton (Arnold), and 6s. QcL 
per ton (Grarside). 

The available resources are at least five hundred million tons. 

The Lower Greensand of Plitwick (pit one-third mile north of 
the railway station, worked by Mr. Joseph Arnold) is similar, but 
less pure. Analyses of this sand are given in the Tables on pages; 
156 and 163. 



<30 BEITISH SANDS SUITABLE TOE GLASS-MAKING. 

Sand from Q-odstone, Surrey. 

Worked by Messrs. Goodwyn & Sons, Granville Chambers, 
Portman Square, London, W. 1 (owner Sir W. R. Clayton, Bart.). 

Maps. Geological : Old Series, 1-inch, Sheet 6. 
6-inch, Surrey, Sheet 27 S.E. 

Situation.Lat. 51 15' 0", Long. 4' 0" W. 

The pit revealing the whitest sand occurs half a mile north- 
west of Godstone Church. 

Formation. Folkestone Beds (Lower Greensand). 

Description. The whitest and best glass-sands occur as irregular 
patches in beds more iron- stained. No great supply of standard 
material can therefore be guaranteed, an unfortunate fact in view 
of its proximity to London and the Thames area. The pit is also 
some distance from a railway station. Sand has been sold for glass- 
making, but never in quantities of more than 90 tons a week, an 
amount hopelessly too small. The bulk of the deposit, consisting 
mainly. of the upper beds, is worked for building-purposes, and 
some probably reaches London and is sold as silver-sand for soil- 
dressing and scouring purposes. The lower beds were used for the 
manufacture of glass. 

Of the sands suitable for glass-making the colour is white to 
faint yellow, at its best almost equal to jihat of Fontainebleau 
sand. It changes to faint pink on burning. Washing would 
probably improve slightly some of the second-best sand, which 
would then serve for white bottle-work. The chemical analysis 
yields : 

SiCL 99-56 per cent. 

ALjO 3 0-26 

Fe.,0,, 0-06 

Loss on ignition 0'24 

Total 100-12 per cent. 

From the point of view of glass-making the grade-analysis is 
good (Hate III. fig. 4). It is as follows : 

>0'5 & <1 mm., 0-6 % ; >0'25 & <0'5, 73-0 % ; >0'1 & <0'25, 25'7 % ; 
> 0-01 & < 0-1, 0-2 % ; < O'Ol ,0-5 %. Total sand-grade, >0-1 4<Imm., 
99-3 %. 

res MS j?s _s_ o_ _s_ -i 

Lo-6' 73-0' 25-7' 0'2' 0-5 ; 99'3' J 

_ In mineral composition the sand closely resembles other deposits 
of the same age, such as those from Aylesbury, Leighton Buzzard, 
Lynn, etc., described. The list of minerals and description there 
given hold good for the Godstone deposits. 

The price is 6s. 6d. per ton on truck at Caterham Station 
(S. E. & G. Railway). 

At Oxted and Limpsfleld in Surrey, about two to three miles 
east of Godstone, and at other places along the outcrop, the same 
salhds (Folkestone Beds, Lower Greensand) are rather coarser in 



AND BEICKA.TE SANDS. . 61 

character, the mechanical composition (see Table V. on page 163) 
resembling that of Leighton Buzzard sand. More iron is present, 
and the sands burn redder, but they would be suitable for bottle- 
glass work. The mineral composition is again typical of the Lower 
Greensand. 

Sands of the same age (Lower Greensand), but rather less pure, 
occur at Westerham in Kent and at other localities near. 

Similar sands occur in the Folkestone Beds (Lower Qreensand) 
in Sussex, e. g. near the village of Rogate. The overburden is, 
however, great, and the sands frequently contain patches of 
calcareous material. 

Sand from Reigate, Surrey. 

Worked (1) Doods Road Pit : by Mr. A. B. Apted, Doods Road, 
Reigate; (2) Park Lane Pit: Agent, Mr. H. Sims, Old Town. 
Hall, Reigate. 

Maps. Geological : Old Series, 1 inch, Sheet 8. 

6-inch, Surrey, Sheet 34 N.E 

Situation. Doods Road Pit. Lat. 51 14' 25", Long. 11' 
0" W. ; Park Lane Pit. Lat. 51 14' 5' , Long. 12' 45" W. 

The smaller pit, in Park Lane, is situated about one-third of a 
mile south-west of the Castle, and the larger, Doods Eoad Pit, 
occurs by the northern side of the railway half -way between Reigate 
and Reclhill. 

Formation. Folkestone Beds (Lower Greensand). 
Description. The Reigate sand is similar in age and character- 
to that at Godstone, but the purer parts are of greater extent. 
The iron-staining is distributed in patches, but is never so serious 
as to prevent the sand being worked for second-quality glass 
(sheet-glass, pressed ware, laboratory- ware, etc.). Topley, in the 
"Geology of the Weald," stated (page 141) that Reigate sand was 
used for glass-making. The best seams of sand are equal in colour 
to Fontainebleau sand. The presence of calcareous material in 
places will probably necessitate washing. The chemical analysis- 
is as follows : 

SiO a 98-93 per cent. 

A1 2 6 3 0-67 

Fe 3 3 0-02 

CaO trace 

MgO none 

KaO n.d. 

Ma^O n.d. 

Loss on ignition 0-28 



Total 99-90 per cent. 

The mechanical analysis indicates : * - 

>0-5 & <1 mm., 2-7 % ; >0'25 & <0-5, 79 % ; >0'1 & <0'25, 14'5 % - f 
>0-01 & <0-1, 1-8 % ; <0-01, 2-0 %. Total sand-grade, >0-1 mm., 
96-2 %. 

PCS MS^ FS j_ o^ JL1 

l_2'7' 79-0' 14-5' 1-8 2-6 ; 96-2'J 



62 BEITISH SANDS SUITABLE FOE GIA SB-MAKING. 

The grading is rather variable, a gradual passage from coarse to 
fine sands being frequently observed. The mineral composition is 
typical of the Lower Green sand. The sands should be worked 
with care, both from the point of view of grade and of iron-content. 
That the available resources here are very great is indicated by the 
abundance of caves throughout the Keigate area. Large quantities 
of cream-coloured sand have been removed from these excavations. 
Doods Eoad Pit shows a 40-foot face of sand. 

From the Doods Road Pit, selected fine silver sand is put on 
truck at Redhill Station at Qs. per ton (unwashed). 

The available resources in the area are over one hundred million 
tons. 

Sand from Aylesford, Kent. 

Worked by Mr. Silas Wagon, Aylesford. 

Maps. Q-eological : Old Series, 1-inch, Sheet 6. 
6-inch, Kent, Sheet 31 S.W. 

Situation. Lat. 51 18' 25", Long. 29' 0" E. 

The pit exhibiting the whitest sand lies immediately north-east 
of Aylesford Church. The Nickle pit, a quarter of a mile west of 
the church, contains rather yellower sand (worked by the Nicopits 
Sand Company, Ltd.). 

Formation. Folkestone Beds (Lower Greensand). 

Description. Whitish sands with a northerly dip are covered 
in one part of the pit by the red ferruginous sandstone known as 
carstone. About twelve feet of the sand are worked, but the 
floor of the pit was covered with water at the time of writing. 
White chalky matter is often present. The general characters 
Are similar to those of the other Greensand deposits described. 

The colour is pale grey to cream, but the sand burns up pink. 

The chemical analysis of the best sand is as follows : 

SiO,, 99-06 per cent. 

A1 2 6., 0-56 

Fe 2 3 0-04 

CaO 0-17 

MgO trace 

K,0 0-26 

Na a O 0-11 

Loss on ignition -22 



Total 100-42 per cent. 

The grading is good, a mechanical analysis being as follows : 

>0-5 & <1 mm., few grains only ; >0-25 & <0'5, 88-7 % ; >0'1 & <0-25, 
16'0 % ; >0-01 & <0-1, 0-3 % ; <0-01, none. Total sand-grade, 
>0-1 & <1 mm., 99-7 %. 

es MS JFS a_ s -i 

fa? 83-7' 16-0' 0-3 : 99-7' J 



SAND FBOM HOLLINGBOITBNE AND BEAE8TED. 63 

The mineral composition is that o the Lower G-reensand 
generally, tourmaline, staurolite, and kyanite being large and 
conspicuous in the heavy mineral crop. 

The sand is supplied on ship upon the Medway at Aylesford at 
8s. per ton, and on truck at Aylesford Station (S. E. & C. Rail- 
way) at 9s. Qd. It is used for bottle-making at Queenborough, 
but would be of service for better glass. 

The available resources are about five million tons. 



Sand from Hollingbourne and Bearsted. 

Not at present being worked. 

Maps. Geological : Old Series, 1-inch, Sheet 6. 
6-inch, Kent, 43 N.W. 

Situation. Lat. 51 16' 0", Long. 35' 30" E. 

The chief excavations, in the form of caves, lie nearly half a mile 
east-south-east of Bearsted Church, and one mile south-east of the 
railway station. 

Formation. Lower Greensancl (Folkestone Beds). 

Description. Sands were stated to have been worked formerly 
at Bearsted, Hollingboume, and Aylesford*, for making the 
commoner kinds of glass, "about 1000 tons being annually shipped." 
The caves at present existing at the first two localities testify to 
the extent of the former working. The sands are similar in 
diameter to those of the same age at Aylesford, Godstone, and 
Keigate, the caves being very similar to those of the last-named 
place. The sand is cream-coloured, turning after ignition to a 
browner tint. A chemical analysis yielded the following result : 

SiO, 99-25 per cent. 

A1 2 0, 0-31 

Fe 2 3 0-04 

CaO 0-09 

MgO none 

LOBS on ignition 0-31 



Total 100-00 per cent. 

Alkalies absent. 

A mechanical analysis yielded the following figures : 

>0-5 mm., none; >0-25 & <0'5, 94' 6 % j >0'1 & <0'25, 4'2 % ; >0'01 & 
<0'1, 0-8 % ; <0-0], 0-4 %. Total sand-grade, >0'1 mm., 98'8 %. 



PMS PS B_ e . S "I 
I_94-6' 4-2' 0-8' 0-4' 98'8'J 



The mineral composition is similar to that of the Lower G-reen- 
sand generally (see pages 50,54-59), the percentage of heavy detrital 



* Mineral Statistics : Mem. Geol. Snrv. I860, p. 374. 



64 BRITISH HANDS SUITABLE FOB GLASS-MAKING. 

minerals of density greater than 2'8 being 0'026. Large kyanite 
(0 - 4 mm. diameter), staurolite, and tourmaline grains (0'2 mm.) 
are abundant; ilmenite, zircon, rutile, and linaonite (O'l mm.) 
are common, and flakes of muscovite mica (O'G mm.) are also 
present. 

The sand requires to be carted one mile by road to the nearest 
station, Hollingbourne (S.E. & C. Railway) ; Bearstead Station is 
about two miles away by road. 

The available resources in this district are over twenty million 
tons. 

Lancashire Sand. 

Worked by a considerable number of glass-manufacturers and 
sand-merchants. 

Maps. Geological : Old Series, 1-inch, Sheet 89 S.W. 

6-inoh, Lancashire, Sheets 92 N.E., S.E. ; 100 N.E., 
S.E. ; 101 N.W., S.W. 

Situation Lett. 53 28' to 53 33', Long. 2 44' to 2 50' W. 

The pits and excavations are situated in the belt of country 
running south-east to north-west from St. Helens to Onnskirk. 

Formation. Glacial Sands. 

Description. The sands are worked extensively for the making 
of bottles and window-glass (at and near St. Helens), also in 
connexion with the soap-industry. The deposits occur at Crank, 
Rookery, Kainford, Kings Moss, Upholland, Skelmersdale, etc.*, 
north-west of St. Helens, and are used locally, so that no great 
amount of transport takes place. Skehnersdale, the farthest distant, 
is about nine miles from St. Helens. The sands are brown, 
frequently dark brown, in colour, and are very peaty. They occur 
in a series of hollows now drained by the small streams which flow 
south-eastwards to St. Helens and Warrington, and so into the 
Mersey. In late Glacial or post-Glacial times, these hollows were 
doubtless badly drained, and became filled with vegetation which has 
yielded the present peaty material. The abundance of place-names 
containing " Moss " is very significant. The decomposition of the 
vegetable matter has had a reducing effect on the ferric oxide in 
the sands, and in many cases, by the action of the acid peaty waters, 
has dissolved the iron out. The sands are worked to the drainage- 
level, usually a depth of about four feet only, and the turned-over 
knd is again devoted to agriculture. The sands are washed at the 
various localities where they are won, and it is interesting to see 
in operation all styles of washing, from the most primitive to the 
latest and most effective. In the former case, the sands are washed 
by being run into shallow troughs and boxes let into the ground, 
where the material is kept in motion by shovelling. Paddle- 
methods of washing are also used, as well as modern rotary, 
dredging, and worm appliances. Vegetable matter is screened off, 

* The Shirdley Hill sands of the Geological Survey Memoir, " The Superficial 
Geology of S.W. Lanos." 1877. 



LANCASHIRE AND HFTTONS AHO SANDS. 



and the water after washing is coffee-coloured with -peaty and 
dissolved ferruginous compounds. 

Mechanical analyses of washed and unwashed samples from 
Rainford are as follows : 





OS. 
>0-5 & 

<1 mm. 


MS. 
>0-25& 
<0-5. 


FS. 

>o-i& 

<0-25. 


a. 
>0'01 & 
<0-1. 


0. 

<0-01 
mm. 


S. 
Total sand-grade : 
>0'1 mm. 


Unwashed ... 
WaBhed 


3-3% 
1-3 


83-0 % 
84'5 


11-7% 
18-1 


0-9% 
0-2 


M% 
0-9 


98-0% 
98'9 

















The material is thus fairly well-graded and of suitable size in 
grain. 

Although the sand is of a medium brown colour even after 
washing, the iron-content is low. The following are chemical 
analyses of Kainford Sands : 



Washed. 

SiO 96-59 

3 1-72 

3 0-03 

OaO 0-19 

MgO 0-08 

K a O 1-05 

Na.,0 0-05 

Loss on ignition 0*43 



Unwashed. 
Fe tt O a 0-05 percent. 



Total 100-14 per cent. 

Duplicate determination, K a O, I'Ol % ; Na 2 0, 0-08 % . 

The available resources are over a hundred million tons. 

Sand from Buttons Ambo, near Malton, Yorks. 

Worked by The High Silica Sands Company, Commercial 
Street, Norton, Malton. 

Maps. Geological : New Series, 1-inch, Sheet 63. 

Old 93N.E. 

6-inch, Yorkshire, Sheet 141 N.E. 

Situation. Lat. 54 5' 50", Long. 51' 40" W. 

Greyish and pale yellow sands occur at Sleights and Hutton 
Bank, and the working is in process of development. 

Formation. Upper Estuarine Series (Lower Oolites). 

Description. The sections at present exposed show in the lower 
part ten to seventeen feet of cream-coloured sands with a small 
admixture of kaolin. Black specks of ilmenite are in places rather 
abundant. The sand is improved by washing, which removes 
calcareous and aluminous material also. The kaolin may be' an 
advantage in the making of certain glasses, and for other purposes 



66 BEITISH SATTDS SUITABLE FOR GLASS-MAKING. 

it is easily removed if desired. Unwashed, this deposit serves 
excellently for bottle-glass making and for lining the hearth- 
bottoms of steel furnaces. (See Plate IV. figs. 1 & 2.) One seam 
of the sand is extremely pure, but most will have to be washed. 
The sand reddens slightly on burning. 

A chemical analysis of a washed sample is as follows : 

SiO a ..................... 99-04 per cent. 

A1A ................. 0-84 

Fe.O.j .................. 0-03 

CaO ..................... 0-10 

MgO .................. 0-18 

Loss on ignition ...... 0'19 



Total ......... 100-38 per cent. 

Before being washed, the sand contains 0-13 per cent, of iron oxide. 

The mechanical analysis indicates : 

>0-5 & <1 mm., 1-4 % ; >0'25 & <0'5, 84'9 % ; >0'1 & <0'25, 75 % : 
>0-01 & <0-1, 4-1 % ; <0-01, 2-1 %. Total sand-grade, >0'1 & 
<1 mm., 93-8 %. 

PCS MB ES _a_ _o JJ_ -I 
Ll'4' 84 ; 9' 7-5' 4-1' 2'1 ; 93-8-J 

The upper part of the sections reveals beds, twelve feet in thick- 
ness, of yellow and brown clayey sands with greyish carbonaceous 
layers. Much more " bind " occurs in these beds, and the deposit 
is of great value for refractory purposes such as steel-casting. 

The chemical analysis of the latter refractory sand is as follows : 

SiO, ........................ 83-8 per cent. 

^AiA ........................ 9-2 

Fe 2 3 ..................... 1-6 

CaO ........................ 0-6 

MgO ........................ trace 

LOBS on ignition ......... 4*7 



Total 99-9 percent. 

Anal. : S. Hewitt. 

The sand is quartzose, felspar being much less abundant than in 
the Kelloway Beds. In mineral composition the sand does not 
exhibit a rich variety of minerals, the heavy residue being coarse 
(averaging O2 mm. diameter). Very little magnetite is present, 
but ilmenite is abundant. Limonite and leucoxene occur. Large 
red garnets are common, and also tourmaline, staurolite, deep red 
rutile, and zircon. Grains of serpentine are occasionally seen. 

The workings have now been considerably developed, a seventy- 
yard face having been opened up. A siding from the N. E. 
Kailway, between Castle Howard and Ehrtfcons Ambo, has been 
built. It is hoped that the sand will be delivered at Knottingley 
and other places in the Yorkshire area at 7*. to 9s. per ton. It is 
put on truck at Huttons Ambo at 3s. 3d. per ton. 

The estimated resources are one million tons. 



BimYTHOJtPE SAND. 67 

Sand from Burythorpe, near Malton, Yorks. 

Working given up some years ago. 

Maps. Geological : New Series, 1-inch, Sheet 63. 

Old 93N.E. 

6-inch, Yorkshire, Sheet 42 N.W. 

Situation. Lat. 54 4' 40", Long. 48' 40" W. 

Whitish sands are exposed in several pits, the chief of which 
lies near the Fox Cover, and three-quarters of a mile north-west 
of Burythorpe Church. 

Formation. Kelloway Beds of the Jurassic. 

Description. As in the case of the countiy around Leighton 
Buzzard, Middleton and Gayton, Q-odstone, etc., the sand supports 
only a poor heath flora by means of which its fairly extensive 
outcrop is vaguely defined. Some years ago it was worked for 
glass-sand, but the Avorldng was given up; it may be re-exploited 
shortly. 

The sand possesses a slight brown tint, due to irou -staining, but 
the best quality is nearly white (cream-coloured). The tint 
becomes slightly browner on burning, but the original colour, 
which lies between those of Fontainebleau and Belgian sands, is 
not improved to any extent by washing, although calcareous 
material is removed. 

The chemical composition is as follows : 

Pox Cover Burythorpe 

Pit. Pork. 

SiO, 96-79 96-70 per cent. 

Al.,6, 1-63 1-49 

TiO,' n.d. 0-35 

Fe.d, 0-22 0-07 

Cab' n.d. 0-12 

MgO ' n.d. 0-07 

K. 2 n.d. 0-84 

Na.,0 n.d. 0-08 

LOBS on ignition 0-60 0*56 



Totals 99-24 100-28 per bent. 

The dominant grade of the sand is smaller than that of foreign 
and also other British glass-sands, but this is an advantage, 
for the deposit is well-graded (see Plate III. fig. 5). 

In the mechanical composition the grade-percentages are : 



>0'5 & <1 mm., few grainn only; >0-25 & <0'5, 39-2 % ; >0'1 & 

59-0 % ; >0'0i & <0-1, I'O % ; <0'01, 0'8 %. Total sand-grade, >0'l' 
&<1 mm., 98-2 %. 

rCS MS FS s o S 
l_tr.' 39-2' 59-6' 1-0' 0'8 ; "98 1 ! 

The grains mostly consist of subangular clean quartz, but grains 
of turbid felspar are not uncommon. The heavy residue is abundant 
and consists of much fine-grained dark material (average diameter 



68 BBTT1SU SANDS SUITABLE l'0il G-LASS-MAKIKG-. 

O'l mm.). In character it most resembles the mineral assemblage 
of the Inferior Oolite, which is remarkably similar all over its 
outcrop across England, from the Dorset coast to Yorkshire. 
Abundant magnetite and ihnenite occur, and colourless to pale 
brown and pink angular garnet grains (O12 mm. diameter) make up 
most of the residue. Kutile is extremely plentiful and zircon is 
common (both about Ol mm. or less diam.). Staurolite and grey- 
brown tourmaline grains occur. Muscovite is present, but the 
diameter of the flakes (0'12 mm; diameter) is not much larger than 
that of the average for the rest of the grains. 

The question of transport to the nearest railway station, Malton 
(almost 5 miles), the high railway freights, and also the distance to 
the nearest port are serious considerations. The great glass-making 
area of Yorkshire is, however, near at hand. 

Some trial-borings and a trial-hole have recently been put down 
a short distance away in Burythorpe Park by the owner, B. JB. 
Colton JFox, Esq. The best of the sand brought to the surface 
looks very promising, and subject to an improvement in the 
economic conditions specified above, development of the area may 
be expected. (For analyses, see Tables, pages 156, 162.) 
The available resources in the area amount to three million 
tons. 

Less pure sands in the Kelloway Beds are worked at South Cave, 
near the station (by Messrs. T. H. Lyon and Partner, of Norton, 
Malton). They are of service for white bottle-glass and much 
other ware. Similar sands occur at Newbald. At Sancton, near 
by, white micaceous sands are found in the Estuarine Series. 

Sand from Denford, Northamptonshire. 

Worked by the Ebbw Vale Steel, Iron & Coal Company, Ltd., 
Irthlingborough. 

Maps. Geological : Old Series, 1-inch, Sheet 52 N.W. 
6-inch, Northamptonshire, Sheet 33 N.W. 

Situation. Lett. 52 22' 20", Long. 33' 45" W. 

The pits, which have really been opened for the purpose of 
exploiting the Northamptonshire Ironstone below the sand, occur 
nearly one mile west-south-west of Denford Church. 

Formation. Estuarine Series (Inferior Oolite). 

Description. Sands occur at the same geological horizon near 
by at Corby, Wansford, Apethorpe, Blatherwyke, etc., and were 
mentioned as having been worked for glass-making about 1860. 
Unfortunately, the variability and limitation in quantity which 
detracted from the value of these affect also the Denford deposits. 
It might be possible to get a good average quality by washing, 
but the sand is too fine in grain to be easily washed without 
considerable loss (see page 122). 

The sand is cream-coloured and burns up pink. A chemical 
analysis of an average sample is as follows : 



DENFOBD AND LONGBOWS' SANDS. 69 

Si0 2 98-19 per cent. 

Al,0 3 1-23 

Fe,0 3 0-06 

CaO 0-15 

MgO none 

LOSB on ignition 0'46 



Total 100-09 per oent. 

The effect of washing would be to remove certain ferruginous 
pellets that occur, and to reduce appreciably the iron-percentage, 
which is already low. 

The sand is veiy fine in grain and is well-graded, a mechanical 
analysis indicating : 

>0-5 mm., none; >0>25 & <0'5, 2-9 % ; >0'1 & <0-25, 92-3 % j >0'01 & 
<0-1, 3-0 % ; >0-01, 1-8 %. Total sand-grade, >0'1 mm., 95'2 %. 

[-MS F8 a o S "I 
|_2-9' 92-3' 3-0' 1-8 : 95'2'J 

The sand carried an abundant and dark residue of heavy detrital 
minerals, the portion of density greater than 2'8 being 0'38 per cent. 
The residue is dark as a result of the preponderance of ilmenite, 
.and the mineral assemblage resembles that of the Inferior Oolite 
generally in its outcrop across England. The following is a list of 
the common mineral species in order of abundance : Ilmenite and 
iron ores, garnets, zircon, red rutile, kyanite, tourmaline, glauconite, 
.staurolite, muscovite, and yellow anatase. 

The available resources, owing to the variability of the beds, are 
probably small. 

Sands of similar age ("Inferior Oolite), but less pure, occur at 
Tadmarton, about four miles west-south-west of Banbury. The pit 
is situated half a mile east of Tadmarton Church (Lai. 52 2' 12", 
.Long. 1 25' 5" W.), and is worked by Mr. H. H. Salmon. About 
.sixteen feet of rather variable sands containing peaty layers may 
be seen. Some of the bands are more iron-stained, rendering the 
profitable working of the pit for glass-sands, in view also of 
the location, improbable. The sand is coarse] 1 than that from 
Denford (see Table of Mechanical Analyses, page 162), but the 
mineral composition is similar, large pink and brown garnets, large 
staurolite, grey-brown tourmaline, abundant ilmenite and iron ores, 
.zircon, and red rutile being characteristic. 

Sand from Longdown, near Southampton. 

Worked by Messrs. Sandell Bros., 79 High Street, Southampton. 
Maps. G-eological: New Series, 1-inch, Sheet 315. 
Old 11. 

6-inch, Hampshire, Sheet 72 N.E. 
Situation. Lat. 50 52' 30", Long. 1 29' 10" W. 



BEITISH SANDS SUITABLE FOB GLASS-MAKINCK 



The pits are worked a little to the south-east of the hamlet of 
Longdown in the New Forest, and are situated about four miles 
west-south-west of Southampton West Railway Station (L. & 
S. W. Kailway). 

Formation. Barton Sand (Upper Bagshot Beds). 

Description. Sand from Longdown, situated upon land in 
the New Forest belonging to the Crown, was mentioned as 
having been worked for glass-making, and sent to the north of 
England, as early as 1858*. It is said to have been nearly 
as white as the Isle of Wight sand, and to have cost Qd. per 
cubic yard. Assuming a cubic yard to contain 30 cwts., we- 
should now consider this price exceedingly low. 

Two sets of pits are at present being worked. At the western end 
may be seen a fifteen-foot section of fine-grained, cream-coloured 
sand, containing yellowish patches and streaks which are more- 
plentiful near the top. The overburden is very small. At the 
eastern end of the excavation red and yellow sands form a thicker 
topping, and the white sand is less constant. The latter is worked 
down to ground-water level. 

If the sand were washed the iron-content and grading would 
doubtless be much improved, but the washing-plant at present on 
the market is not well suited to the rather fine grain of the sand. 
Inevitable loss of fine sand would result. Washing improves the 
colour slightly, and samples of the sand on ignition become a 
rather darker brown. The chemical composition indicates : 

SiO, 95'41 per cent. 

Al.,0., 2-35 

Fe 2 On 0-09 

CaO! 0-26 

MgO 0-18 

K a O 1-33 

Na.^0 trace 

Loss on ignition 0'50 



Total 100-12 per cent. 

After being washed the sand contains 0-06 per cent, of iron oxide- 
(asFeA)- 

The deposit is fine-grained, mechanical analyses being as 
follows : 





MS. 


FS. 


B. 


0. 


S. 




>0-25& 


>0-1& 


>0-01 & 


<0-01 


Total sand-grade : 




<0'5mm. 


<0-25. 


<0-1. 


mm. 


>0-1 mm. 


Western end . . . 


8-9% 


84-6 % 


3'8 % 


27% 


93-5 % 


Eastern and , . . 


5-9 


91-2 


1-5 


1-4 


97-1 



* Mineral Statistics : Mem. Gteol. Survey, 1860, p. 374. 



SAND. 71 

The heavy minerals of density greater tban 2'8 constitute 
0-08 per cent, of the whole. Large flakes (0'4 mm. diameter) of 
a greenish nmscovite are very abundant. Brown tourmaline 
(O'l mm.), kyanite (0'2 mm.), iron ores, including ilmenite 
(altered to leucoxene), magnetite and liinonite, are plentiful. 
Zircon and rutile in small grains about 0'05 mm. in diameter 
occur commonly, and the presence of epidote and green hornblende 
(O'l mm.) was also noted. 

The sand is carted by road about two miles to Lyndhurst Eoad 
Station (L. & S. W. Railway), where it is put F.O.R. at Qs. per 
ton. Two miles' cartage eastwards will also bring the sand to a 
small quay on Southampton Water owned by Messrs. Sandell Bros., 
the water-freight to the London area being about 2s. Qd. and to 
Bristol 3s. per ton before the war. The sand is at present being 
supplied to the Bristol area (railway-freight about 10s. per ton) for 
bottle-making, but it is sufficiently good for better quality glass. 

The sand occupies several square miles of wooded country, and 
the available resources are certainly not under four million tons. 

Sand from near Fordingbridge, Hants. 

Working being undertaken by Mr. A. J. Terrill, Eosebank, 
Fordingbridge ; Lybum Estate, owned by Cecil Lee, Esq. 

Maps. Geological, 1-inch. New Series, Sheet 315. 
6-inch, Wiltshire, Sheet 77 S.E. 

Situation. Lat. 50 57' 30", Long. 1 39' 30" W. 

The locality is actually across the county boundary in Wiltshire, 
but Fordingbridge is the nearest town. 

The pits occur near "No Man's Land" about five miles east- 
north-east of Fordingbridge, and nine miles south-east of Salisbury. 

Formation. Bagshot Sand. 

Description. Wide stretches of sandy heath occur in this area. 
For the greater part the sands have been bleached white, or are 
coloured grey by an admixture of peaty material. So far as the 
small excavations enable the observer to judge, a bed of pale grey 
sand at least six or seven feet thick (the greatest depth yet proven), 
and probably much thicker, extends over a considerable area. 

The sand is pale brown in colour and becomes grey on ignition. 

The chemical analysis of a bulk sample as collected is as 
follows : 

SiO a 99-28 per cent 

AL,0., 0-17 

TiO a '. 0-07 

Pe..0 a 0-02 

Cab: , 0-11 

MgO none 

K.jO none 

Na 2 none 

Loss on ignition 0'27 

Total 99-92 per cent. 



74 BRITISH SANDS SUITABLE FOll Q-LABS-MATCINO. 

The chemical analysis is as follows :--- 

SiO, 95-21 per cent. 

ALP, 2-43 

Fe^O'a 0-42 

CaO 0-19 

MgO none 

K.,0 0-89 

Na,0 0-19 

Loss on ignition . . . 0'88 



Total 100-21 per cent. 

The mechanical analysis indicates that the grade of " fine sand " 
is dominant, as in the Burythorpe deposit : 

>0-5 & <1 mm., none; >0'25 & <0'5, 16-2 % ; >OvL & <0-25, 79'6 % ; 
>0-01 & <0-1, 3-1 %; <0-01, 1-1 %. Total sand-grade, >0'1 & 
<1 mm., 95-8 %. 



TMS JF3_ _B_ _c S -I 
Ll6'2' 79-6' 3-1' 1-1 ' 95'8'J 



In mineral composition the sand resembles the Thanet Beds 
generally along the southern outcrop, the detrital minerals being 
fairly abundant, and occurring in angular grains. Ilmenite 
(altering to leucoxene) and limonite (O2 mm. diam.), zircon 
(O'l.rnm.) and rutile (0 - 2 mm.) abound, and tourmaline (0'2 mm.), 
staurolite, ? andalusite, and flakes of muscovite (0'2 mm. diam.) are 
also found. 

Bail and river are near, and the sand is supplied at about 3*. Qd. 
to 5s. per ton at the pit (Is. 6rf. and upwards per " foot "). 

The available resources of glass-sands are over two hundred 
thousand tons. 

Thanet Sand near Rochester is similarly worked for the bottle- 
industry at Queenborough, Higham, etc. 

Sand from Worksop. 

Worked by Messrs. Jas. Turner & Son, Ltd., Kiveton Park, 
near Sheffield, and at Worksop. 

Maps. Geological : Old Series, 1-inch, Sheet 82 N.E. 
6-inch, Nottinghamshire, Sheet 8 S.W. 

Situation. Lot. 53 18' 48", Long. 1 7' 64" W. 

The quarry, in which the sand suitable for glass-making is. 
exposed, lies about one-third of a mile west of Worksop Station 
(Q-. C. Eailway). 

formation. Lower Bunter. 

Description. The excavations being made for Messrs. Turner's 
new glass-works, which are in course of erection, have revealed 
an excellent section of Permian marls. The marls are purple and 
green in bands, and the basal Bunter Sands rest upon their wavy 
upper surface. Fifteen feet of pale-coloured sands are seen, of 



WOKJCSOP SAJfJ). 75 

which the lowest seven or eight feet are worked for glass-making. 
In places these sands have a pale greenish appearance, and certainly 
appear to have a better colour where they occur below ground- 
water level. This may be due to solution of ferric compounds 
by algal or bacterial action. It is proposed to treat this bed by 
tank-washing, but at present the sand is being shipped to the 
Tyneside glass-works just as it is quarried. The uppermost few 
feet of the pale sands contain ferruginous streaks and patches, 
lied sand, strongly current-bedded and rather coarse in grain, 
forms the upper part of the section, fifteen to twenty feet high. It 
is worked as an " open " moulding-sand and for building-purposes. 

The glass-sand is pale brown in colour and darkens on heating. 

A washed sample analysed by Mi-. J. H. Davidson, M.Sc., of the 
Department of Glass Technology in the University of Sheffield, 
gave the following result : 

SiO., 95-10 per cent. 

ALA 2- 32 

TiO.> trace 

Fe,6., 0-51 

OaO! 0-22 

MgO 0-24 

Loss on ignition 0-54 

Alkalies, by difference . 1'07 

Total 100-00 per cent. 

An average sample of unwashed sand (as sent to the North of 
England) collected by the writer contained only O10 per cent, 
of ferric oxide. 

The mechanical analysis is as follows : 

>l mm., 2-0 % ; >0-5 & <1 mm., 6'6 % ; >0'25 & <0-5, 58'65 % ; >0'1 & 
< 0-25, 26-15%; >0-01 &<0-1,4'5 %; <0-01, 2'1%. Total Hand-grade, 
>0-1 mm., 93-4%. 

rvcs cs MS PS_ _B _o_. s I 

L 2-0 ' 6-6' 58-65' 26 ; 15' 4-5* 2-1 ' 93'4' J 

The percentage of alumina in the sand is an advantage for bottle- 
making, as it strengthens the glass. The alumina is present partly 
as felspar, and partly as its decomposition product kaolin. Much 
of the latter washes' out of the sand, and its presence is indicated 
by the high clay-grade in the mechanical analysis. 
L In mineral composition the deposit resembles many other Bunter 
Sands. Ilmenite is abundant but very much altered to leucoxene. 
Yellow-brown and grey tourmaline in highly rounded grains are 
very abundant. Pink garnets (0-2 mm.), angular staurolite, and 
apatite also occur. Zircon and red rutile (O'lxO'03 mm.) are 
plentiful. 

The quarry lies by the side of the G. C. Railway from Sheffield 
to Ketford (via Worksop), and the Chesterfield Canal, which has, 
hoAvever, fallen into disrepair, especially in the adjacent Norton 



76 BRITISH SAjSDS SUITABLE FOB GLASS-MAKING-. 

Tunnel. The sand is supplied F.O.R. at Worksop (unwashed) at 
3s. Qd. per ton. It could be put on boat on the canal for about 
4s. Qd. per ton. 

The available resources are over six million tons. 

At Alderley Edge, Cheshire, occur large tips of sand which 
have accumulated from the copper and lead mines (6-inch Map, 
Cheshire, 28 S.W. Lot. 53 17' 40", Long. 2 18' 15 <( ). The 
Keuper Waterstones are impregnated at this locality with galena 
(lead sulphide) and malachite (copper carbonate). The sandstones 
were formerly mined, and after being crushed were treated with 
acid to dissolve the metalliferous ores. The resulting sand was 
washed to recover as much as possible of the metallic salts, and 
has thus accumulated as waste material. 

The acid treatment has doubtless removed part of the iron oxide, 
but about 0'12 per cent, remained in a sample tested. The sand is 
pale brown and becomes greyer after ignition. It is markedly 
felspathic. The alumina present in the felspar would add to the 
value of the sand for bottle-making, when the iron-content would 
certainly not be too high for pale bottles. 

In consequence of the washing, the grading is fairly good, as the 
following analysis indicates : 

>0'5 & <1 mm., 2-4%; >0'25 & <0'5, 76'9%; >0vl & <0'25, 17'2%; 
>0-01&<0-l,l-6%; <0-01,1'9%. Total sand-grade, >0'1 mm.,96'5%. 



PCS MS FS a o S ."I 
l_2 T 4' 76-9' 17-2' 1-6' 1-9 J 96 : 5j 



Unfortunately the deposits are not situated upon a coalfield or a 
bottle-making area, and it is doubtful whether it would pay to 
move the sand as far as either the Manchester or Yorkshire districts. 
The mines are situated about one and a half miles south-east of 
Alderley Edge Station (L. & N. W. Railway), the road being u 
good one and downhill. , 

Dune-Sands and Shore-Sands. 

Although some of these sands, the analyses of which are given 
in the Tables (pages 157, 165), have been used for bottle-glass, no 
blown-sand or shore-deposit from the British Isles pure enough 
(with the exception of that from the Isle of Jura) and in sufficient 
quantity for the making of flint or better-class glass lias yet been 
seen by the writer. The constituents of these sands have usually a 
very mixed origin ; but if local derivation from, decomposing pure 
sandstones or quartzites can be ensured, suitable sands may be found. 
Usually, in dune- and shore-sands, current-action tends to defeat 
this object. Nevertheless, the dune- and shore-sands of the 
United Kingdom (especially those bordering the Archaean areas of 
Scotland and Ireland) ought to be more thoroughly investigated 
than they have been. The colour of such sands varies from pale 



iDUJS'E-SAJSDS A5TD SHOJtE-SAlTDS. 77 

grey and brown to deeper tints, and usually darkens considerably 
on burning. Too much iron is present, and the heavy mineral 
crop is frequently large. Commercial electromagnetic separation 
will hardly clean the sands sufficiently. They are of little use 
except for "black" glass-work when the industry is located close 
at hand. 

The purest shore-sand met with is that occurring on the western 
shores of the Isle of Jura, and derived from the Dalradian 
quartzites forming the greater part of the island. This sand is 
said to have been formerly worked for glass, but it is of limited 
extent and, although very white-looking, contains O07 per cent, 
of iron oxide. 

The beach-sand from the Isle of Eig'g is also of fairly good 
quality, and consists of very clean and colourless angular quartz, 
mixed with a considerable quantity of dark kaolinized felspar, but 
it yields a large crop of heavy minerals derived from neighbouring- 
igneous masses (augite, olivine, epidote, garnet, zircon, etc.). 

Similar sands from near Dublin (Sandymotuit Strand) have 
been used in the dark-bottle industry of that city. 

Additional shore- and dune-sands from Ireland have, also been 
examined in view of the needs of the bottle-industry *. Samples of 
blown sands .from Button (Kilbarrick) near Dublin, Washing Bay, 
Coalisland (on Lough Neagh), Ballycastle (Co. Antrim), etc., 
have been examined and analysed, with the results given oi> 
page 165. 

GK H. Kinahan. in his account of the economic geology of Ire- 
land f, mentions the occurrence at Ballycastle of a white sand suitable 
for glass-making, stating that it occurs as Drift. It lies upon and 
is presumably derived, at any rate in part, from the Carboniferous 
Sandstone. The sand worked for the old Ballycastle Glass-works, 
(up to 1820) was blown-sand from the dunes, not a very pure 
material, and the glass made was a rough thick green bottle-glass 

only- 
Specimens of a shore-sand from Maghera, Ardara, Co. Donegal, 
have been forwarded by the Officer in Charge of the Coastguard 
Station, who says that the quantity available is unlimited. The 
sand is unfortunately somewhat shelly and rich in heavy detrital 
minerals. The iron -percentage (Fe a 3 ) is 0'7 per cent. A similar 
but slightly less pure sand has been obtained from Sandflelds, 
Ardara. Mechanical analyses of these sands will be found in the 
Tables. 

Besides those sands analyses of which are given later (see 
pages 167, 165), samples from the following localities (sent by the 
courtesy of Sir Bertram Windle, F.R.S., President of University 

* Prof. Gilbert Morgan issued a report on Irish Glass-sands shortly after 
the outbreak of war. This statement mentioned, besides Muckish Mountain 
Sand, deposits which might bo worked for bottle -making', and whioh occurred 
at Sutton near Dublin, Bosslare, Silver Strand (Wicklow), Ardara (Co. Done- 
gal), and Washing Bay (Lough Neagh). 

f Journal Royal Geol. Soo. Ireland, vol. viii. (1887). 



78 BRITISH SAtfDS SUITABLE FOR GLASS - 

College, Cork) have been examined : Castlefreke (Cork), Clay- 
castle (Youghal), Glenbeigh (Keny), Kilkee (Kerry), and Rush- 
mere (Tramore). 

Information regarding other sands investigated will be found in 
the Tables or, incidentally, in the remarks below. Sandstones and 
quartzites naturally disintegrated or crushed to produce "glass- 
sands " are discussed in Chapter VII. 



CRUSHED BOOKS. 79 



CHAPTER VII. 

A. PURELY SILICEOUS DISPOSES (continued}. 
(6) CRUSHED BOCKS. 

Many crushed quartzose rocks have been placed upon the market 
as proposed substitutes for glass-sands. At the outset, it may 
be said that they have never found much favour with British 

Fig. 12. Mechanical Analyses of Glass- Sands : Crushed RocTcs, etc. 
100%-t m 



10 - 



, 

- 



'0 0-5 O-Z5 0-1 mms. 

> Grade Sizes (diameter in Mil I i metres) 

manufacturers, although such materials appear to be exten- 
sively used abroad. The great evil of rock-crushing lies in the 
quantity of dust, which is waste material, produced. Mining 
engineers are still endeavouring to devise a machine that will grind 
or crush rocks to a fine even grade without producing slime. 
So far as glass-making materials go, the remarks regarding the 
un suitability of sand not of even grade apply still more empha- 
tically here. Several pure sandstones and quartzites, of various 
geological ages from pre- Cambrian to Coal Measures, occur in the 
British Isles, and a few have been crushed and exploited. Mechanical 
analyses of the products are given in the Tables. Sifting is usually 
carried out at the quarries, and so those coarse grades which are 
objectionable are eliminated. Large quantities of fine grades and 



80 CRUSHED EOCKS. 

t 

dust are, however, produced, and, in order to yield an effective 
sand, these ought to be washed away with water-currents of 
strength calculated as above from elutriation data. It is frequently 
necessary to remove electromagnetically the iron particles derived 
from the crushing-plant. The cost of quarrying, crushing, and 
sifting has generally been too great to permit of washing also, 
and the price of the unwashed material is often prohibitively high, 
even in the neighbourhood where it is produced. Much more is 
the cost increased by the usual heavy freights, so that there is 
little likelihood of such materials replacing glass-sands to any 
extent for ordinary work in this country. High-content of silica, 
and alumina also if that is desired, low iron, and general purity 
and angularity are their chief recommendations. Difficulties 
occur in the use of these crushed rocks. Often it does not pay 
to wash them, and consequently loss results from the burning 
out of the fine grade, and unevenness in the " metal" is caused by 
irregular melting. The fine material carries with it air-bubbles, 
from which the "metal" is cleared with great difficxilty. As in the 
case of crushed quartz-crystals themselves, it is also objected by 
many glass-manufacturers that the "metal" produced from' the 
crushed material tends to be "cordy" or "wavy" and to remain 
" sticky " too long upon cooling, which also takes a longer time 
than is desirable. Whether this is the result of the mixture of 
fine grades, of the presence of two allotropic low temperature forms 
of quartz, differing crystallographically, one possibly as a cement, 
of the different hydration of the silica acting as matrix, or of the 
presence of certain inclusions in the quartz, is not known. Greater 
heat, or more prolonged melting of the batch, appears to be re- 
quired when crushed rocks are used *. It is noteworthy that the 
sand obtained from Muckish Mountain, Co. Donegal, Ireland, is a 
naturally disintegrated pure pre- Cambrian quartzite. It is often 
difficult to draw the line between a true sand and such a disinte- 
grated sandstone or quartzite. The mechanical analyses on page 82 
indicate, however, that it has been well-graded, probably a result 
of percolating waters for a long period, helped by the fact that the 
original sandstone was also well-graded, and most of the cement 
has since been removed. It contains rather too much coarse 
material, but this is very friable, and can be rubbed down in the 
fingers, compound-grains thus breaking up. The analyses (see 
also Fig. 12) should be compared with those of Guiseley material 
(which was supplied sifted to 40 -mesh), Port-a-cloy Silica, 
Westport Silica, etc. Even after washing and sifting, the residual 
rock-particles are distributed over several grades and the mixture 
is still unsatisfactory. 

Among decomposed or crushed sandstones and quartzites ex- 
amined were the following : 

* On the behaviour of the forms of silica, see Fenner, Ainer. Journ. Science, 
vol. 36 (1913) p. 331, and Jonrn. Wash. Acad. So. TO]. 2 (1912) p. 471 ; Wright 
& Larson, Amer. Journ. Science, vol. 27 (1909) p. 421, and others. 



MUCE:ISH MOUNTAIN SANDSTONE. 81 

Muckish Mountain Sand, Co. Donegal. 

Worlced by Messrs. Arkwright & Rapaport, 22 Bank Buildings, 
Kingsway, W.C. 2. 

Maps. Geological: Old Series (Ireland), 1-inch, Sheet 10. 
6-inch, Donegal, Sheet 34. 

Situation. Lat. 55 6' 20", Long. 7 59' 50" W. 

The sand lies on the top and upper slopes of a hill (Muckish 
Mountain) of quartzite about four miles from the sea, and about 
thirty- three miles east of north of Donegal. It consists of scree 
material resulting from the decomposition of the quartzite. 

.Formation. Pre- Cambrian (Dalradian) . 

Description. Trial- workings are being carried out to ascertain 
the extent of the sand. Many pits and trenches, including one 
driven twenty feet into the hillside, have now been made, and a 
considerable area of rock cleared of grass, peat, and rubble. The 
amount of sand still appears to be small, but the excavations have 
proved the existence of several beds of considerable extent, 
consisting of soft white sandstone a result of the partial disinte- 
gration of the quartzite. All the chemical analyses of Muckish 
Mountain material reveal the presence of a small quantity of lime 
(CaO), so that it is possible that the sandstone was once cal- 
careous, perhaps bearing a calcareous cement, and that the calcium 
carbonate has been leached out as a result of the weathering 
agencies and acid peaty waters. The rock is seen in all stages of 
decomposition, from hard flinty quartzite to a friable sandstone 
which can be broken up in the fingers. The quantity of actual 
unconsolidated sand present is very limited. 

As the seams of soft rock occur immediately below the flat top 
of the mountain, over two thousand feet above sea-level, it is 
probable that much of the soft rock will be reduced to sand in the 
process of running it down the shoots to the foot, However, 
a certain amount of the material will not be broken up in this way 
and will require crushing. (See Plate IV. figs. 3 & 4, which show 
the manner of cementation of the grains.) Owing to the softness 
of the cement, this will not be a difficult or expensive matter. 
Screening is also necessitated, since the crushed and decomposed 
products contain coarse compound grains which remain as "stones" 
in the glass made from the rock. Washing is desirable to assist 
the grading by clearing the sand of fine dusty silica, etc., and to 
reduce the iron-content of the browner varieties. The available 
water-supply is small, especially in the summer. 

The chemical analyses, of some samples of the rock recently 
collected are as follows : 
Bulk sample, mixed from all the trenches. 



SiO., .................. 99-55 per cent. 



Fe,0, ............... 0-02 

CaO ' ................. 0-20 

Mg-0 ............... trace 

Loss on ignition ... 0-16 

Total ......... 100*10 per cent, 



Iron-content. 

Trench 1 0-028 per cent. 

2 0-022 

3 0-009 



CRUSHED ROCKS. 



The brown colour of many specimens is due to staining by peaty 
waters and is not detrimental. One such brown variety contained 
only 0*029 per cent, of iron oxide (Fe a O s ). 

Mechanical analyses of the same samples are as follows : 





vos. 


OS. 


MS. 


FS. 


s. c. 


S. 




>1 


>0-5& 


>0'25& 


>0'1& 


>0'01& 


<0-01 


Total sd.-gr, : 




mm. 


<1 mm. 


<0'5. 


<0'25. 


<o-i. 


mm. 


>0'1 mm. 


Trench 1 ... 




2-5% 


72-3 % 


19'9 % 


3-0 % 


1'8 % 


95-2% 


2 ... 


2-0 % 


14-7 


73-9 


7-9 


0-5 


1-0 


98'5 


2a... 




9-8* 


73-1 


15-8 


0-8 


0-5 


98-7 


3 ... 


2-5 


13-6 


75'4 


7-5 


1-0 


o-o 


99-0 


A fine seam . 




0-3* 


36-7 


58-3 


3-2 


1-5 


95'3 



* Compound grains. 

The rock contains a very small proportion of heavy detrital 
minerals, little else but zircon being present. The sand was used 
by the Irish Department of Agriculture in the reproduction of 
Waterford Glass for the Cork Exhibition in 1902. Good glass has 
also been made from it in the London, Birmingham, and Yorkshire 
.areas. 

The price at which this material is to be supplied has not yet 
been fixed. Should it not be low enough to enable the sand to 
replace foreign supplies in England, we may still be assured, in the 
Muckish Mountain deposit, of a large supply of material of excellent 
quality, sufficiently good for the making or the best optical glass. 

The nearest port is Ballyness, six miles from the foot of the hill. 
The Donegal Eailway runs about a mile from the foot, and the 
port of Dunfanaghy is six miles distant. 



Crushed Sandstone from Guiseley, near Leeds. 

Worked by The Guiseley Ganister Company. 

Maps. Geological : Old Series, 1-inch, Sheet 92 S.E. 
6-inch, Yorkshire, Sheet 202 N.W. 

Situation. Lat. 53 52' 5", Long. 1 44' W. 

The quarry lies one mile west-south-west of Guiseley. 

Formation. Coal Measures. 

Description. The purity and high silica-content of certain 
sandstones of Coal Measure age are well-known and the rocks on 
that account are prized. The Guiseley rock is much shattered, and 
is washed at the quarries, being supplied at present to the steel 
industry. It is proposed to crush and sift the rock for glass-making. 
The sifted product is free from coarse grains, but naturally is spaced 
over several grades, and contains objectionable fine material. The 
cost of washing, to rid the sand of' the latter, is somewhat pro- 
hibitive, the price without washing varying from 15s. to 17s. per ton 
even in the neighbouring Yorkshire glass-making area. However, 



AXD MOLD SANDSTO2O3S. 83 

certain glass-manufacturers are trying the sand. It is white, 
bears only a small quantity of iron, and does not darken on burning. 
The chemical analysis of the crushed rock is as follows : 

SIC., ........................ 97<45 per cent. 



Fe,0 3 ........................ 0-09 

Cab ........................ 0-13 

MgO ........................ trace 

Loss on ignition ......... 0'78 



Total 100-21 per cent. 

An un crushed sample of rock yields the following analysis : 

Si0 2 98-93 per cent. 

AU). } : 0-60 

Fe^O 3 0-03 

CaO 0-24 

MgO none 

Loss on ignition 0-29 



Total 100-09 per cent. 

The greater amount of iron in the crushed sample is therefore 
presumably due to additional impurity obtained from the crushers. 
The mechanical composition, after sifting to 40-meshj is : 

>0-5 & <1 mm., 0-1 % ; >0-25 & <05, 40-1 % ; >0'1 & <0-25, 
44-3 % ; >0'01 & <0-1, 9-2 % ; <0-01 mm., 6'3 %. Total sand- 
grade, >0-1 mm., 84'5 %. 

? j?. s A j 

l' 40-1' 44-3' 9-2' 6*3 ; 84-5' 

The mineral composition indicates the presence of very rare 
felspar, a colourless flake of garnet (?), anatase growing on ilmenite, 
abundant small red-brown rutile, zircon, limonite, leucoxene, etc. 

Sandstone from Mold, Flintshire. 

Worked by The Mineral Milling Company, Mold. 

Maps. 1-inch Geological, Sheet 79 S.E. 
6-inch Flintshire, Sheet 13 N.W. 

Situation. Lat. 58 10' 20", Long. 3 11' 12" W. 

The mine occurs at Waen, immediately north of the Smithy, 
one hundred and fifty yards north of Trinity Church and about two 
miles west of Mold. 

.Format ion . Carboniferous Limestone. 

Description. The bed of white sandstone is about twenty- three 
feet thick and occurs below a bed of Carboniferous Limestone, 
which in the shaft is about twenty-two feet thick. Impure 
limestone also occurs below the sandstone. At present the rock is 



84 CRUSHED HOCKS. 

mined and brought up the shaft, but a drift is being run eastwards 
from the surface down to the working. The sandstone is of good 
colour \\ith little or no iron-staining. It is constant in quality and 
grade, and is soft and easily crushed. After ignition, the colour 
remains unchanged. The unwashed product contains only 0-024 per 
cent, of iron oxide. The washed product has the following chemical 
composition : 

SiO, 98-97 per cent. 

Al,6 a * 46 

TiO, 0-04 

Fe 2 s 0-02 

CaO 0-10 

MgO 0-07 

K 2 0-08 

Na^O none 

Loss on ignition 0*34 



Total 100-08 per cent. 

The crushed material is fairly well-graded, as the following 
result of a mechanical analysis indicates : 



>0-5mm.&<lmm. 5 9'2 % ; >0'25 & <O5, 78'1 % ; >01 & <0'25, 10'5 % ; 
>0-01 & <0'1, 0-9 % ; H)1, 1-3 %. Total sand-grade, >0-1 mm., 
97-8%. 

? 5! JL S JL _2_ J? .1 

2' 78-1' 10'5' 0-9' 1-3' 97*8 J 

Washing improves it by removing the fine dusty material. 

The heavy detrital minerals form a very small percentage of the 
whole (0-01 per cent.). The assemblage includes only the stable 
commonly-occurring detrital minerals, such as magnetite in well- 
shaped crystals, ilmenite altering to leucoxene, and with crystals of 
anatase growing upon it, tourmaline in bluish, greenish, and brown 
grains (all O'l to 0'2 mm. diameter), together with tiny zircons 
and rutiles (0-05 mm. diameter). The sandstone also contains- 
decomposed felspar. 

The material is utilized in the manufacture of abrasive soaps, 
but should also be of much value for glass-manufacture and for 
refractory purposes. 

Two miles of good road connect the mines to Mold Station 
(L. & N. W. Railway), where it is put uncrushed F.O.R. at 
17s. 6^. per ton. The crushed product can be similarly supplied 
at about 20s. to 22s. per ton. 

The available resources are over ten million tons. 

The deposits of sandstone at Pant du and Minera are similar in 
character to that described above, but are on the whole less pure. 
The highly siliceous ^ sand " from Mow Cop in Cheshire is of the 
same character and is worked for pottery purposes (see pages 155 
and 161). 



SPITAL SANDSTONE. 85 

The pulverized material obtained from the cutting and dressing 
of sandstones of Millstone Grit age at Eowsley, in Derbyshire, is 
used for the making of common bottle-glass in Derby. 

"SpitalSand." 

Worked by Mr. H. A. Walker, 13 Imperial Buildings, Exchange 
Street East, Liverpool. 

Maps. Geological: Old Series, 1-inch, Sheet 79 N.E. 
6-inch, Cheshire, Sheet 13 S.E. 

Situation. Lat. 53 21' 5 ', Long. 3 1' 45" W. 

The quarry is situated at Higher Bebington, near Spital, half a 
mile south-south-west of the Church, and over one mile west-south- 
west of Bebington Railway Station. 

Formation. Keuper Waterstones. 

Description. About thirty to forty feet of creamy-white, soft 
sandstone are exposed in a large quarry, showing strong faulting on 
the western side. Like many of the Keuper deposits, the sandstone 
is felspathic, much of the orthoclase felspar having decomposed to 
kaolin -like material. The sandstone, which is easily crushed, 
therefore yields a poorly-graded deposit. Washing would effect a 
considerable improvement in the sand, so far as glass-making is 
concerned. 

In its present state it is used for making pale bottles (Dublin, 
Belfast, etc.), and as a refractory material in the iron, steel, and 
copper industries. 

Although the grains are coated in part with white clayey matter, 
the sand, which is about equal in colour to that of Lynn, darkens 
on burning. The chemical composition is as follows : 

SiO a 94-60 per cent. 

Al.,0., 2-99 

Fe"0 3 0-06 

CaO 0-20 

MgO 0-14 

K 2 1-44 

Na 2 none 

Loss on ignition O65 



Total 100-08 per cent. 

Another sample, after being washed, showed an iron-content of 
0-09 per cent. 

Although the clayey matter is objectionable, there is little doubt 
that the alumina present strengthens considerably the bottle-glass 
made from the sand. 

The mechanical analysis is as follows : 

>0-5 & <1 mm., 0-7% ; >0-25 & <0'5, 81-7% ; >0-1 & <0-25, 13-6% 
>0'01 & <0-1, 1-4%; <0-01, 2-6%. Total sand-grade, > 0-1 mm., 
96-0%. 



r^ -? - . . s - ~i 

|_0-7' 81-7' I3 7 6 5 1-4' 2-6 ; 96-6 J 



86 CRUSHED HOCKS. 

The microscopic examination of the rock indicates that the 
heavy minerals are remarkably well-rounded, but that the variety 
among the commonly-occurring minerals is not great. A. little 
magnetite is found, but ihnenite (0-2 mm. in diameter) is much 
more abundant, fellow-brown, highly rounded grains of tour- 
maline are veiy plentiful (0'2 to 0*3 mm.), and characteristic deep 
blue and purplish grains occur. Tiny zircons and rutiles (0*1 mm. ) , 
and yellow to colourless anatase crystals (0*1 mm.) also are seen. 
The heavy detrital residue amounts to 0'06 per cent.. 

The crushing strength, tested on 3-inch cubes (average of four 
tests) is 1450 Ibs. per square inch. 

The price is 7*. W. per ton F. O.E. at Spital Station (L. &N.W. 
& G.W. Joint Railway), and 9s. 6d. F.O.B. at Birkenhead. 

The available resources are over twenty million tons. 

Sand from Caldwell, tf.B. 

Worked ly The Caldwell Sand Company Ltd., per Mr. Wm. F. 
Pirrit, 96 Eenfielcl St., Glasgow. 

Maps. Geological, 1-inch, Sheet 22. 

6-inch, Renfrewshire, Sheets 15 N.E. and 16 N.W. 

Situation, Lot. 55 46' 15", Long. 4 29' 0" to 20" W. 

Several quarries occur on the south-east side of the Barrhead 
Eoad, nearly a mile north-east of Caldwell Station (Glasgow & 
South Western Railway). The quarry at present being worked is 
the most westerly of them-. 

Formation. Carboniferous Limestone Series. 

Description. The quarry exhibits about twenty to thirty feet 
of soft decomposed sandstone of variable colour, from cream to red- 
brown. The strata dip north- westwards towards the road, and 
shale is revealed in the bottom of the quarry, underlying the 
sandstone. Pebbly seams occur, and in parts the sandstone is coarse 
and not well-graded. 

On ignition the sand darkens slightly to a brown tint. The 
chemical analysis of an unwashed sample of the best material 
available for glass-making is as follows : 

SiO 2 , 93-74 per cent. 

A1 2 3 4-11 

EeoO'a 0-04 

CaO 0-27 

MgO 0-12 

K,0 0-46 

Na.jO 0*03 

Loss on ignition 1-37 



Total 100-14 per cent. 

Another washed and screened sample contained 0-08 per cent, 
of iron oxide. 

The mechanical analyses of washed and unwashed samples 
(collected at different times) are as follows : 



CALBWELL AND KILWHTNTNG SANDSTONES. 



87 







i 










OS. 


MS. 


FS. 


s. 


c. 


S. 




>0-5 & 
<1 mm. 


>0'25& 
<0'5. 


>0-1 & 
<0-25. 


>0-01 & 
<0-1. 


M)1 

mm. 


Total sand- 
grade : 
>0'1 mm. 


Unwashed ... 


5'5 % 


82-9% 


5-8% 


1-1 % 


4-7% 


94-2 % 


Wasted 


21-0 


69'4 


8-9 


0-5 


0-2 


99-3 



The mineral analysis indicates the abundance o large pink and 
colourless garnets (O5 mm. diameter) with good crystal form, 
uruscovite flakes (0*4 mm.), grey tourmaline (0*1 mm.), limoiiite, 
ilmenite, abundant zircon and red rutile, and, rarely, epidote. The 
heavy mineral crop constitutes 0'08 per cent, of the sand. 

The material is crushed in a pan -mill, washed in rotary apparatus, 
and screened before being supplied to the G-lasgow steel-area. 
Some of the other quarries were formerly worked for glass-sand, 
but at present the output is taken entirely for refractory purposes. 

The prepared material costs 10s. per ton F.O.R. at Caldwell 
Station (Glasgow & South Western Railway). 

The available resources are over two million tons. 

Sand from Zilwinning, N.B. 

Not at present being worked. 

Maps. G-eological, 1-inch, Sheet 22. 

6 -inch, Ayrshire, Sheet 11 S.JE. 

Situation. Lat. 55 39' 33", Long. 4 44' 45" W. 

The outcrops of white sandstone occur close to the south-western 
end of Ashgrove Loch, near to Lochcraigs Farm, about a mile and a 
half west-north-west of Kil winning Station. A less pure sandstone 
of slightly different age crops out by the roadside near Bankend 
Farm, north-east of the Loch. 

Formation. Carboniferous Limestone Series. 

Description. A considerable area of rough ground and crags 
overlooking the southern end of the Loch is occupied by the 
outcrop of a bed of white sandstone which is apparently over 
twenty feet thick. The sandstone is white and breaks down easily 
in the fingers. It looks decidedly promising for glass-making and 
refractory purposes, and after being washed yields a well-graded 
and pure sand, which becomes greyer on ignition. 

The chemical composition of an unwashed sample is as follows : 

SiO.> 98-85 per cent. 

Al.,6 3 0-53 

Ti6 2 ! 0-06 

Fe O 3 0-02 

OaO 0-11 

MgO . 0-06 

K 2 O trace 

Na.,0 none 

Loss on ignition O f 38 

Total 100-01 per cent. 



88 



CBUSHED BOOKS. 



The iron-content of another washed sample is OO28 per cent. 

Some of the material is fine in grain and rather well-graded 
(sample J). Other samples collected were much coarser. Mechanical 
analyses are as follows : 





















VOS. 


OS. 


MS. 


FS. 


S. 


0. 


s. 




>1 mm. 


>0-5 & 
<1 Tnnn. 


>0-25 & 
<0-5. 


>o-i& 

<0-25. 


>o-oi & 

<0'1. 


<0-01 
mm. 


Total Band- 
grade: 
>0'1 mm. 


Unwashed (a) . 


13-5 % 


30-0 % 


54-6 % 


1'1% 


0-2% 


0-6% 


99-2 % 


Washed (6) ... 




0-5 


92-5 


5-5 


0-5 


1-0 


98-5 



[(a) and (Z>) were different, samples of sand.] 

A mineralogical analysis shows the presence of ilrnenite and 
leucoxene, limonite, muscovite (flakes Q'5 mm. diameter), brown 
tourmaline (0*3 mm.), sillimanite, red. rutile, and zircon (O'l mm.) 
among the heavy crop of minerals, which amounts to O02 per cent, 
of the whole. The heavy residue of the sample examined was 
rather coarse in grain. 

Difficulties may arise over transport. The nearest station is 
Kilwinning, hut to reach it half a mile of rough farm-track and a 
quarter of a mile of fairly good road have to he traversed. 

The available resources appeal 1 to he not less than half a million 
tons. 



Sand from Levenseat, K.B. 

Worked by Messrs. J. & T. Thornton, Levenseat Quarries. 

Maps. Geological : 1-inch, Sheet 31. 

6-inch, Edinburgh, Sheet 10 S.E. 

Situation. Lat. 55 48' 30" to 45", Long. 3 41' 40" W. 

The sandstone is being worked in several quarries, about one and 
a half miles east-south-east to south-east of Fauldhouse Station, 
and one mile south-east of Crofthead Station (Caledonian Railway). 
.The chief quarry is the most southerly and lies on higher ground 
about three-quarters of a mile south of Levenseat Hamlet. 

Formation. Millstone Grit. 

Description. The best face of sandstone is that revealed in the 
quarry on the higher ground, where a thirty -foot wall of the deposit, 
practically free from overburden, is to be seen. In the lower 
quarries several feet of Drift occur above the bed, and shale is met 
with about four feet below the floor of the pit. In all, the workable 
sandstone bed is probably about eighty feet thick and covers a wide 
area. The stone, yellowish to brown in colour, has decomposed 
until it breaks down readily into sand when rubbed in the fingers 
or on being dropped into water. On ignition it darkens to a red- 
brown tint. Much of the yellow 'or brown staining washes away 
freely from the grains of quartz, clayey matter is removed from 



LEVENSEAT SANDSTONE. 



89 



tlie decomposed felspar, and a well-graded cream-coloured sand is 
yielded. On ignition the washed product becomes slightly darker. 

The chemical analysis of a washed sample is as follows : 

SiO a 99-46 per cent. 

ALO. 0-16 

TiO, 0-04 

Fe 2 a 0-03 

OaO 0-13 

MgO none 

K 2 none 

Na 2 none 

Loss on ignition 0*19 



Total 100-01 per cent. 

Before being washed, a sample of the sand was found to contain 
0'07 per cent, of ferric oxide. 

The result of washing is also to improve the grading veiy con- 
siderably indeed, a well-graded material is produced : 





OS. 


MS. 


FS. 


s. 


c. 


S. 




>0-5 & 


>0-25 & 


XML & 


>0-01 & 


<0-01 


Total sand- 




<1 mm. 


<0-5. 


<0'25. 


<0-1. 


mm. 


>0-1 mm. 


Unwashed ... 


3-7% 


88-5 % 


6-0% 


0-2% 


1'6% 


98-2 % 


Washed 


a few 


94-3 


5-5 


0-1 


0-1 


99-8 




grains. 













The mineral composition of the sand calls for little note and the 
heavy crop amounts to only 0-09 per cent. The most commonly- 
occurring heavy detrital minerals are ilmenite altering to leucoxene, 
zircon, rutile, and brown and grey tourmaline. The heavy residue 
is fine-grained, the average diameter being O'l mm. 

In its unwashed state, the sandstone, after having been crashed 
in a pan-mill and screened, is sent to the Edinburgh district for the 
making of green bottles, floats, etc. The alumina present adds 
considerably to the tensile strength of the glass. Arrangements 
have now been made, it is satisfactory to add, by Mr. Hugh Reid 
of Motherwell, to wash the sand in tank-washers. The washed 
product should be of high quality, and, as the above analysis 
indicates, of great value in the steel industry for furnace purposes. 

The unwashed crushed material is put F.O.R. at Crofthead 
Station at 9s. a ton. 

The available resources are probably over fifteen million tons. 

Other Carboniferous Sandstones of the Midland Valley of Scot- 
land have been worked extensively for building-stone. Among 
these are the rocks from Cowle and Plean, two localities near 
Stirling, Kingacavil, near Linlithgow, Grlenboig, and Hailes near 



90 CRUSHED BOOKS. 

Edinburgh. Most of these are soft greyish-white or pale brown 
sandstones, with occasional carbonaceous layers. 

The sandstone of Corallian age which is associated with coal and 
oil-shale ("parrot") at Erora is greyish- white, and is fine and 
regular in grain. The best exposure is in Clyneleish Quarry, half 
a mile north-west of Brora, but although the rock is fairly soft, it 
could not be crushed and transported to a glass-making area at 
other than a prohibitive price. A certain amount of sand, the 
result of decomposition of the rock, is also to be found. The 
material is not pure enough for the making of good gkss-ware, 
the iron-content (as Fe 2 s ) being 0-12 per cent., but it might 
serve for refractory purposes. 



Sand from Ballycastle, Co. Antrim. 

Not at present being worked : Ballycastle Estate ; Agent, 
Capt. S. J. Lyle, M.C. 

Maps. 1-inch Geological, Sheet 8. 
6-inch, Co. Antrim, Sheet 5: 

Situation. Lat. 55 12' 50", Long. 6 11' to 6 13' W. 

The exposures of cream-coloured sandstone occur in the cliff- 
sections, east of Ballycastle, from "White Mine to Gobb, a distance 
of about a mile. 

Fwrnation. Lower Carboniferous Sandstone. 

Description. About sixty feet of whitiah sandstone occur above 
the Main Coal of the Ballycastle Coalfield. In the upper portion 
shale bands occur, and the best sandstone material is the "post" 
which forms the roof of the Main Coal. The sandstone crops out 
along the shore and is visible in the cliffs at White' Mine, where it 
is seemingly purest and best-graded, Griffin Mine, Gobb, and other 
places. Much lateral variation in particular sandstone beds is to 
be observed. The Main Coal is at present worked by Messrs, 
Heckie, Aiton & Kerr (Ballycastle Colliery). In view of the 
proximity of fuel, availability of machinery, and abundant water- 
supply, it should be possible to work and treat this sandstone 
economically. The rock is soft and easily crushed. It would 
also need washing and screening. ' 

The sand, which is cream-coloured, becomes browner after 
ignition. The chemical composition is as follows : 

Si0.j 98-57 per oent. 

ALO 9 0-52 

TiO 0-05 

Pe a O a 0-02 

OaO 0-20 

MgO 0-05 

Z a O 0-06 

Na.,0 0-05 

Loss on ignition 0*42 



Total 99-94 per cent. 



BALLYCASTLE AND COOKSTOWN SANDSTONES. 

The mechanical composition of a crushed sample is : 



91 





OS. 


MS. 


FS. 


s. 


0. 


S. 




>0'5& 
<1 mm. 


>0-25<fc 
<0'5. 


>0-1 & 
<0-25. 


>0-01 & 
<0-1. 


<0-01 

TTlm. 


Total sand- 
grade : 
. >0-1 mm. 


Unwashed ... 


3-3% 


82-8 % 


12-0% 


1-1% 


0-8% 


98-1 % 


Washed 


5-3 


87-3 


6-5 


0-6 


0-3 


99-1 



In mineral composition, the sandstone resembles other Coal- 
Measure Sandstones of the north of Ireland. The heavy residue, 
forming O03 per cent, of the sand, is coarse in grain, and consists 
chiefly of the stable and common minerals, zircon, rutile, limonite 
(all about - 2 mm. in diameter), muscovifce (O4 mm.), and 
anatase. 

The railway facilities are not good (the Ballycastle Railway 
links Ballycastle to Ballynioney on the Midland, N. C. I., Railway), 
but a pier and a jetty are also close at hand. ' 

Messrs. Heckie, Aiton & Ken* propose to work the deposit at 
White Mine, and the British Silica & Minerals Company Ltd. 
that at Gobb. The material, being a high-silica sand, is ot value 
as a refractory material (for furnace-linings, etc.) as well as glass- 
making. 

The available resources are undoubtedly large. 



Sand from Cookstovni, Co. Tyrone. 

Worked by Richard duff, Esq., Kildress House, Cookstown. 

Maps. 1-inch Geological, Sheet 26. 
6-inch, Co. Tyrone, Sheet 29. 

Situation. Lat. 54 38' 40", Long. 6 47' 0" W. 

The pit is situated in the townland of Lower Kildress about 
half a mile east of Kildress House. 

formation. Calciferous Sandstone (Upper Group). 

Description. About thirty feet of soft sandstones are exposed in 
the pit which is by the side of the small stream known as the 
Ballinderry River. The upper portion is stained red and brown, in 
part as a result of the percolation of peaty waters and in part by 
oxide of iron. Ferruginous bands, often wedge-shaped, also occur 
lower down, but the iron oxide is not present in large quantity, 
and washing frees the quartz-grains easily from the pink pellicles. 
Some six or seven feet of pure white sandstones are seen. The 
sandstone is thoroughly decomposed and washing in water serves to 
disintegrate it. Screening, however, must be adopted to free the 
product from quartz-pebbles and harder sandstone pellets. 

The red sands darken in colour on ignition, and the cream- 
coloured sand becomes greyer. 



92 



CHTTSHED HOCKS. 



The chemical composition is as follows : 

SiO a 96-97 per cent. 

Al,0 3 1-61 

Fe a 3 0-04 

GaO 0-20 

MgO 0-11 

K a O 0-15 

Na a O 0-03 

Loss on ignition 0'72 



Total 99-83 per cent. 

- The iron -content of a washed sample of reel sand is O04 per cent., 
and of the cream-coloured sand, P 02 per cent. 

Much clayey material (kaolin) is present a result of the 
decomposition of felspar. After "being washed, the sand is well- 
graded, as the following mechanical analyses indicate : ' 





vcs. 


OS. ! MS. 


FS. 


B. 


c. 


S. 




>1 mm. 


>0-5 & 
<1 mm. 


>0-25 & 
<0-5. 


>0-1 & 
<0-25. 


>o-oi & 

<0-1. 


<o-oi 

mm. 


Total sand- 
grade-. 
>0-1 mm. 


Unwashed. 


1-8% 


9-7% 


80-6 % 


4-2% 


0-8% 


S'4% 


96-8 % 


Washed ... 


2-0 


8-1 


79-0 


10-1 


0-8 


,0-5 


99-2 


, 




i 











The heavy mineral residue (0-03 per cent.) is fine in grain and 
consists mainly of zircons (0'05 mm. diameter). Other minerals 
noted were yellow rutile, anatase growing on ilmenite, and brown 
and blue tourmaline. 

At the present time the mixed and unwashed sand is sold for 
bottle-making in Belfast at about 20s. per ton, which represents a 
cost of 14s. tid. per ton at Cookstown Station. From the quarry 
to the station three miles of road-transport are necessary. If the 
* white sandstone were washed and screened, the material would 
serve for the making of glass of much better quality. Water-power 
and an abundant water-supply are available. 

The resources are difficult to estimate, but are considerable. 
The liability of the rocks to vary laterally introduces difficulty in 
computation. 



Sand from Coolieeragh, Londonderry. 

On the eastern side of the Foyle, and north-east of Coolkeeragh 
House, five miles north of Londonderry, a small excavation has been 
opened by Mr. John Bums, the owner of the estate. Soft white 
and pale-reddish sandstones are visible, apparently of about the 
same age and very similar in appearance to those at Cookstown, 
etc. (Upper Calciferous Sandstone). ,The same rock occurs also at 
White Castle on the shores of the Foyle, but is much less accessible. 



BOOKS PEOM COOLKEEBAGH AND POBT-A-CLOT. 



93 



The Coolkeeragh rock breaks down very easily, disintegrating when 
placed in water. In its present state it serves for bottle-making, 
but if washed and screened would be useful for better-class glass- 
making. On ignition it becomes greyer, and the chemical com- 
position of an unwashed sample is as follows : 

SiO., 84-96 per cent. 

Al a Oj 8-59 

TiO s 0-18 

Fe-jO,, 0-18 

CaO 0-34 

MgO 0-31 

Z a O 4-54 

Na a O .., 0-08 

Loss on ignition 1-54 



Total 100-72 per cent. 

Another sample collected by the writer contained 0-13 per cent, 
of feme oxide, while the content of a washed sample was 0-075 
per cent. 

Washing removes also the kaolin yielded by the decomposing 
felspar, and results in the production of a well-graded sand, as the 
following mechanical analyses indicate : 





VCS. 


OS. 


MS. 


FS. 


B. 


c. 


S. 




>1 mm. 


>0-5 & 

<1 mm- 


>0-25 & 
<0-5. 


>0-1 & 
<0-25. 


>o-oi & 

<0-1. 


<0-01 
mui. 


| Total Band- 
grade : 
>0-1 mm. 


Unwashed ... 




M% 


75-9% 


7-5 % 


3-0 % 


6-5% 


90-5% 


Washed 


M% 


2-7 


90-4 


4-6 


0-5 


0-7 


98-8 



The mineral assemblage is like that of other sandstones of 
similar age in northern Ireland (Cookstown, Ballycastle, etc.), the 
commonly-occurring heavy minerals (which form 0'05 per cent, of 
the sand) being muscovite and chlorite (flakes 0'6 mm. diameter), 
brown tourmaline, small irregular and angular garnets (O'l mm.), 
small zircons and rutiles, leucoxene, and plentiful anatase, in yellow 
tablets or growing upon ilmenite. 

The deposit is favourably situated for transport. The Midland 
Kailway (Londonderry to Coleraine and Belfast) is only a few 
yards distant, and the deposit is close to the Eiver Foyle. 

Further exploration is desirable before the resources can be 
estimated. 



" Port-a-cloy Silica." 

This material is apparently a decomposed or crushed quartz-mica 
schist (Dalradian), and is to be worked by the China-Clay, Felspar, 



96 



CHUSHED BOOKS. 



A compact and good quality quartzite is worked by Messrs. Win. 
Wild & Sons in extensive quarries 011 Holynead Mountain, Anglesey. 
It is crushed and used for the making of silica-bricks, and for 
" gannister " for lining Bessemer converters, etc. In places it is 
very pure, but joint-planes stained with ferruginous matter spoil it 
for use in glass-making. The quartzite is of pre- Cambrian age 
and frequently exhibits a foliated structure. It is traversed by 
abundant quartz-veins. The chemical composition of a typical 
sample of rock is as follows : 

SiO g 99-32 per cent. 

Al/) 3 0-19 

Ti0 2 0-03 

Fe 4 3 0-02 

Cat) 0-12 

MgO 0-08 

KjO none 

Na 2 none 

LOBS on ignition T. 0'21 

Total 99-97 per cent. 

A similar quartzite, but less pure, has been worked at Forth. 
Wen, near Amlwch, Anglesey. 

The vein-quartz from Slieve More, Achill Island was formerly 
crushed and supplied by the Irish Industrial Minerals Company, 
Westport. 

The chemical composition of a sample of the crushed rock supplied 
(quality No. 3) is as follows : 

SiO., 99-20 percent. 

AijO;, 0-24 

Fe a 3 0-04 

CaO 0-09 

MgO trace 

Loss on ignition 0*23 



, Total 99-80 per cent. 

The uncrushed roek contains 99-51 per cent. SiO a and OOG4 per 
cent. Fe a 9 . Some of the iron seems to have been introduced as a 
result of crushing the material (see page 128). 

The flaky form of the crushed product is seen in Plate IV.fig. 5. 

Mechanical analyses of numbered samples supplied are as 
follows : 





OS. 


MS. 


PS. 


s. 


c. 


S. 


Quality. 


>0-5 & 
<lmm. 


>0-25 & 
<0-5. 


>0'1 & 
<0-25. 


>0-01 & 
<0-1.' 


<0-01 
mm. 


Total sand-grade : 
>0-1 mm. 


.... 






0-3 % 


0-7% 


99-0% 


0-3 % 


1 .... 




fewgrs. 


3-5 


1-8 


94-7 


3-5 


la .... 




2-0% 


17-9 


36-5 


43-6 


19-9 


2 .... 


0-2% 


9-0 


53-5 


23-5 


13-8 


62-7 


3 .... 


1-0 


85-5 


11-6 


0-4 


1-5 


98-1 


4 .... 


54-9 


42-9 


0-5 


0-2 


1-5 


98-3 



QTTAETZITBS AJTD TEDT-QTrAETZ. 97 



Examination of the samples for heavy detrital minerals by means 
of bromoform reveals the fact that, in the crushed material of 
quality 3 as supplied, a large part of the crop of density greater 
than 2'8 (O'l per cent.) consisted of rust-reddened metallic iron 
easily attracted by a bar-magnet. Most of the remainder of 
the residue consists of flakes of a greenish biaxial mica (O3 mm. 
diameter) containing plates and dendritic growths of hematite. 

Before the war, the No. 2 material fetched 27s. to 30s. per ton 
for use in the making of abrasive soaps. 

A foliated micaceous quartzite has also been worked at 
Kildownet in the south of Achill Island. 

At White Bock, about four miles north-west of Tinahely, Co. 
Wicklow, a knob of vein-quartz occurs associated with quartz-mica 
schists. The mass forms a prominent feature on the landscape, and 
is at least a hundred yards long by fifty yards wide. Quarrying 
indicates that it is more than thirty feet deep. The rock quarried 
is a pure white vein-quartz of good quality. It is carted to Tinahely 
Station by road, and thence delivered on the quays at Arklow or 
Dublin. The cost at Arklow of the uncrushed rock is about 6s. Qd. 
per ton, and at Tinahely Station about 4s. Qd. Crushed, rolled, and 
screened material (1 inch to -fa inch) can be delivered into an 
English port at from 28s. to 50s. per ton. Larger-sized material. 
could be similarly delivered at about 25s. per ton. 

The quartz is said to contain 99'50 per cent, of silica. The quarry 
is worked by Mr. E. Page, "Woodenbridge, Co. Wicklow. 

Similar vein-quartz has been supplied from near Ynyslas Station, 
Cardiganshire. The crushed product is far from well-graded, and 
its cost is prohibitive for glass-making. 

Veins of quartz are of wide distribution among the older rocks 
of the west and north of Ireland, Wales, and Scotland. They are 
not often sufficiently thick or persistent to be of economic value. 
Samples have been collected from Anglesey, the Lleyn Peninsula,, 
Bardsey Island, and other localities. 




98 



CHAPTER VIII. 

BBITISH RESOURCES OP GLASS-SANDS, ETC. (continued?). 
B. DEPOSITS CA&RYIN& ALUMINA AND SILICA. 

Alumina commonly occurs in sands and rocks used for glass- 
making in the form of the mineral felspar or the decomposition 
product, kaolin (china-clay), which results largely from the 
.alteration of felspar. Certain rocks as, for example, those of the 
Triassic and Carboniferous Systems are rich in decomposed felspars 
.and contain a certain amount of clayey material. This renders their 
crushed products poorly-graded, but the small proportion of alumina 
present may actually be an advantage, as in the case of bottle- 
making, where strength and toughness are required in the glass. 
Unfortunately, most British sands bearing a high proportion of 
.alumina contain also much iron, and are useless for the manufacture 
of glass-ware other than common bottles. 

A prejudice against alumina in sands for bottle-making was 
formerly met with, but it is now slowly dying out. In rare cases 
Alumina is even added to the batch for bottle-making. Dr. W. E. S. 
Turner, of the Department of Grlass Technology in the University 
of Sheffield, is of the opinion that, far from having a tendency to 
cause devitrification, alumina if in moderate amount has just 
the opposite properties and will prevent glass from devitrifying. 
Experiments have shown that when alumina is added to a window- 
.glass batch, the glass which is produced does not undergo devitri- 
fication when heated in a blow-pipe flame. If the amount of 
-alumina is high, it is possible for a clouded glass to be produced, 
-as when felspar itself is used. According to the investigations of 
Singer *, it is possible to add to a glass-batch containing alumina 
more sand and more lime, and to reduce in proportion the amount 
of alkali, thereby cheapening the cost of production. 

Of the sands and rocks described or mentioned in the foregoing 
pages, those from Sandymount Strand (Dublin), Parsley Hay and 
Brassington (see below), Charltou, South Cave, Huttons Ambo, 
and Leyenseat, carry appreciable, and sometimes large, quantities 
of alumina f. 

The sand from Sandymount Strand is used in the Dubh'n black- 
bottle industry. To give greater "body" to the glass, broken 
lumps of Bridgwater or other homogeneous brick are added to the 
bajxih. The brick is red and is highly ferruginous, as the following 
analysis indicates : 

* F. Singer, 'Die Keramische Rundachau,' yol. v. 1915, "TJeber den 
Einfluss von Tonerde anf die Sohmelzbarkeit von GHasern." 

t See note on page 34 ref erring to sand from Martinroda used for ther- 
mometer-glasB. 



DEPOSITS .CABBYING ALTJimTA AJO) SILICA. 99 



Analysis of Bridgwater Brick. 

SiO, ..................... 58-20 per oent. 

AlA ..................... 16-42 

TiO' ..................... 1-29 

Fe 3 3 ..................... 6-74 

FeO ........................ 0-13 

CaO ..................... 7-37 

MgO ..................... 3-02 

K a O ........................ 3-65 

Nft.,0 ..................... 0-93 

C0 2 ........................ 0-13 

P.,0, ..................... 0-07 

MiiO ..................... 0-08 

LOBS on ignition ......... 2-50 

1 [HjO flJid carbonaceous 

matter.] ' - 

Total ......... 100-53 per oent. 

The addition of the brick increases the depth of colour of the 
"bottles, and undoubtedly strengthens them by toughening the 
glass a result of the addition of the 16 per cent, of alumina. 
"This is a distinct advantage where the bottles have shoulders and 
.are required to stand considerable pressure from contained gases. 

In the St. Helens district a baked clay is added to the batch for 
the same purpose. A partial analysis of such a baked clay from 
.Messrs. Nuttall's works is as follows : 

SiO., ..................... 63-99 per cent 

AlA ..................... 15-17 

TiO a ..................... 0-65 

Fe,0 3 ..................... 6-13 

Total ......... 85-94 per cent. 

" Spital sand " is used for bottlfc-raaking, and contains almost 
:3 per cent, of alumina. The sand from Worksop is similar in 
mineral composition and might well be more extensively used in 
the bottle industry of Yorkshire, which is located close at 
hand. 

Eaglescliffe " sand," mentioned in Chapter X., is a chemically- 
treated rock of the same age. The iron-content has been very 
much reduced (see analyses), but the alumina, forming 3'51 pe*r 
cent., has been retained. The Stiper Quartzite and the Appin 
Qtiartzite are felspathic, and in consequence contain about 2 per 
cent, each of alumina. The Port-a-cloy rock has already been 
described (page 93) and, contains, before washing, 12'66 per cent. 
of alumina. A washed material from it contains still -23 per 
cent, of iron oxide (Fe.,0 a ) and 11'57 per cent, of alumina. 
Kaolin-bearing sands ancl crushed rocks cannot be washed to 
reduce the iron-content without loss also of the alumina (see, 
-for example, the analyses of Huttons Ambo sands on page 65 : 
before washing, 8'68 .per cent. Al.jO n , 1'28 per cent. Fe a 3 ; after 
-washing, 0-84 per cent. Al a 3 , 0'03 per cent. Fe,0 3 ). 

ir 2 



100 -DEPOSITS CAERYINa ALUMINA. AND SILICA. 

In addition to the a"bove, the following alumina-bearing sands* 
and rocks may be mentioned : 

(fl) SANDS, CLATS, ETC. 

Kaolin, as prepared in Cornwall and Devon from the altered and 
decomposed granite, is used in glass-making where resistant or 
tough glasses are required. It is added to the batch in the usual 
way, but since it is a refractory body, greater heat is required to 
get it into solution than is usually required in glass-making. 
Moreover^ aggregates of the mineral sometimes form and are 
difficult to melt up. They tend to remain as "stones." Any 
natural sandy deposit therefore which is low in iron-content and 
rich in kaolin, and has its sand-grains coated evenly by the latter, 
is of considerable value for particular glasses such as those used for 
chemical and pharmaceutical purposes (laboratory apparatus, com- 
bustion tubing, thermometers, ampoules, etc.). Such materials 
cannot, of course, be well-graded. 

The kaolin resources of England have been carefully described 
in detail by J. Allen Howe, in a Memoir of the Geological 
Survey, " A Handbook to the Collection of Kaolin, China-Clay 
and China-Stone in the Museum of Practical Geology " (1914). 
Since the production of the Handbook, fresh but smaller resources . 
have been discovered at Holyhead Mountain, Anglesey (worked by 
W. Wild & Sons Ltd., Brassfounders, Liverpool St., Sheffield), and 
Port-a-cloy, Co. Mayo (The China- Clay & Felspar Company Ltd.,. 
Dublin), as well as a few other localities. 

In the preparation of china-clay (of theoretical composition- 
Alp., . 2Si0 4 . 2H 2 0), great care is taken to eliminate all micas, etc., 
partly because of their coarseness and partly because of the alkalies 
and alkaline eai-ths in their composition which render the clay 
less refractory. For glass-inanufacture the small quantity of 
alkalies in the settlings known commercially as "micas" is not 
objectionable and may even be advantageous. An analysis of 
" coarse micas " mechanically separated at the Standardised China- 
Clay Company's Works at Eoche, Cornwall, is as follows : 

SiO., 48-18 per cent. 

. AlA 36-14 

Ti0 2 ' : 0-15 

Pe,0 3 0-98 

Cat) 0-13 

MgO 0-28 

K,0 2-12 

Na.,0 0-23 

* Loss on ignition H'98 



Total 100-14 per cent. 



The tips of rejected coarse material from the kaolin workings in- 
Devon and Cornwall contain high silica and .fairly high alumina- - 
content. The tourmaline could be extracted by electromagnetic- 



SANDS. 101 

means, and the alumina, is mostly present as micas, kaolin, and 
partially decomposed felspar. The deposits are poorly graded, con- 
taining much coarse quartz and felspar. It is a pity the material 
cannot be made use, of ; sands with a good proportion of alumina 
.are desirable for certain glass-work, and a market is badly needed for 
the rejectamenta from the kaolin-works. The material is utilized 
for the making of refractory bricks. 

Refractory Sands, etc., of Devonshire. 

^The deposits occur in two well-marked basins, south and north 
of Dartmoor respectively. The basin of Bovey has long beeii 
known and has frequently been described and discussed*. Kaolin- 
bearing sands and fireclays, associated with lignites, have been 
worked on a large scale at Heathfield, and also near Newton' 
Abbot. For the greater part, 'the sands bear too much tourmaline 
(boro-silicate of aluminium and iron) to be of use for glass-making, 
-and the electromagnetic separation of the mineral would prove too 
expensive. The deposits are of considerable value for refractory 
purposes. 

The second basin occurs north of Hatherleigh and south of 
Tomngton, in North Devon, and has not yet been described in 
detail. In recent years, large open-cast workings and mines have 
been made in order to obtain the peaty clays and clayey sands for 
the making of fire-bricks and for pottery purposes. The material 
is kaolin-bearing and undoubtedly derived from the Dartmoor 
Granite. A chemical analysis . .of , .Torrington sand is given in the 
Table on pige 157. 

Sands, etc., from St. Agnes, Cornwall. 

Sands of white to yellowish colour, felspathic and kaolin-bearing, 
occur in association with refractory clays near St. Agnes Beacon, 
Cornwall. The deposits, which occur on the 400 ft. platform, are 
believed to be of Pliocene age. They have been used as refractory 
materials, but are of limited extent and thickness. The principal 
pits are close to Beacon Cottage, one mile west-south- Avest of the 
Church and half a mile north of the Beacon (west and west-north- 
west of the Church). The best whitish sand occurs below red 
sand and " candle " clays. The material can be shipped from 
Trevanaunce Cove or Chapel Combe near by, or carted to St. Agnes 
Station (two miles). The resources of the area would very soon be 
exhausted. 

Kaolin from Anglesey. ^ 

On Holyhead Mountain, Anglesey, several dykes occur in the 
pre-Cambrian quartzite (see page 96). They have a north-south 
strike J and vary in width from about twenty feet to a very small 

* See, for example, Mem. Geol. STLTV., "The Geology of the Country 
around Newton Abbot" (Sheet 339), 1913. 



102 DEPOSITS CARHTI>'Q ALUMINA AJU? SILICA. 

amount. It is difficult to say what the original rock of these dykes; 
has "been. In places, the clay now tilling them is somewhat sandy, 
hut in others the clayey material is so pure as to discounfcenance- 
the suggestion that they were originally rnicrogranite. The 
presence of- quartz- veins in the adjacent rock, and at times the- 
abundance of limonitic matter in the ctykes, together with plentiful 
evidence of alteration of the quartzite walls of the veins and dykes, 
suggests hydrothennal action and that the dyke'-niaterials in their 
present form may he secondaiy in origin. The dykes at present 
being worked occur in Messrs. Wm. Wild & Sons' quarry, where 
the clay has heen used as a hinder for the broken quartette in- 
making " gannister " for lining steel-converters. A very good 
grade kaolin has been washed out of the material from another 
of these dykea. The chemical composition of a sample of the raw 
material, which is a clayey sand, is as follows : 

SiO, 94-90 per cent. 

Al.,0., 2-31 

Ti0 ' 0-45 

FeCf 0-48 

Fe 3 0., 015 . 

CaO.' 0-13 

MgO 0-12 

K.0 0-74 

Na a O 0-02' 

MnO tnwe 

Loss on ignition 0'68 

- Total 99'98 per oent. 

The alumina-content of this sample is surprisingly low. It 
probably cannot be taken as typical. 



The Refractory Sands of Derbyshire and Staffordshire. 

The irregular accumulations of sands and clays which occur in 
hollows in the surface of the Carboniferous Limestone district of 
Derbyshire and Staffordshire are well-known on account of their 
highly refractory character. They have been mentioned by Greo. Maw, 
J. Allen Howe, Dr. A. Strahan, and others, but no systematic account 
of them seems to have been written. At present they are utilized 
for the making of high-class silica-bricks, when variability in 
iron-content, up to several per cent., is not detrimental. Selected 
deposits of white to cream-coloured sand or clayey sand might be- 
of considerable value for glass-making, but the* available resources 
are very limited and it will be difficult to keep to sample. 

Tflese kaolin -beaiing sands are free from alkalies, lime, etc., 
and at times cany very little iron oxide. They are worked at 
Carsington Pastures, near Harborough Bocks, at Longcliffe, Low 
Moor, Friden, Blake Moor, Parsley Hay and Alsop en le Dale in 
Derbyshire, and also at Eibden in Staffordshire. The hollows, 
are clean-sided, with fresh limestone walls, steep and sometimes. 



SANDS FROM DERBYSHIRE AND STAJETOJIDSHIRE. 

overhanging. The limestone displays no evidence of ordinary 
weathering. Signs of stratification are visible in the material 
filling the hollows ; the association is not turbulent as described, 
but appears to yield evidence of a definite order related to the; 
succession of the Triassic sediments, which at one time were con- 
tinuous over the whole district. Bunter Sandstone, the Pebble-bed, 
Keuper Marls, and black shale probably belonging to the Bhsetic, 
have foundered into the hollows. The oldest deposits occur nearest 
the walls of the basin. The various sediments have suffered a 
curious alteration, characterized by the production of kaolin 
material and the almost complete elimination of alkalies and alkaline 
earths. The appearance of the workings, especially of the white 
deposits of the central and deeper portions of the basins, is strikingly 
similar to that of the china-clay pits of Devon and Cornwall. One 
area at least reproduced the conditions of the Bovey deposits indeed, 
Geo. Maw noted the similarity long ago, lignites, pipe-clays, and 
refractory sands indicating the filling up of a swampy hollow ^with 
vegetation and kaolin-mud at a time when the bulk of the Triassic 
rocks had been removed, but when foundering was still hi progress. 
Chemical analyses of some of the purest of these deposits are : 

Parsley Hay. Brassington. Ne-wnaven. 



SiO 


. 74-64 




18-04 


TiO "" 


, n.d. 


Pe.,0, , 


0-05 


CaO , 


a-19 


MgO 


none 


E Q 


. n. d. 


Na a O 


. n.d. 


Loss on ignition . , . 


. 7-24 



Totals 



100-06 



90-40 
6-56 
n. d. 
0-18 
0-16 
trace 
n. d. 
n. d. 
2-48 

99-78 



98-17 per cent. 

a- 71 

0-42 

0-025 

0-11 

0'07 

0-09 

0-02 

0-41 



100-025 per cent. 



The composition of the Parsley Hay material corresponds to a 
mixture of about 53 per cent, of pure silica sand, and 45 per cent, 
pure kaolin (of composition A1 2 S . 2SiO a . 2H a O). 

Mechanical analyses of some of the deposits, whieh are neces- 
sarily not well-graded, since they are clayey sands, are : 





OS. 


MS. 


IB. 


8. 


0. 


S. 




>0-5 & 


>0-25 & 


>0-1& 


>o-oi & 


<o-oi 


Total sand-grade; 




<1 mm. 


<0-5. 


<0-25. 


<o-i. 


mm. 


>0-1 mm. 


Parsley Hay ... 


0-3% 


20-2 % 


35-7% 


18-5 % 


80-8 %i 


56-2 % 


rassington ... 


1-5 


71-4 


11-8 


os. 2 ' 1 fs. 


13-2 


84-7 










>0-05. 


<0'05. 






Bibden 


4-6 


43-6 


23-8 


0-6 


10-5 


16-9 


72-0 


Newkaven 


0-2 


49-9 


30-4 


l-o 


10-9 


7-6 


&0-5 


Longoliffe 


2-2 


58-6 


23-7 


0-7 


5-2 


9-6 


84-5 


Oaraington ... 


2-0 


68-7 


11-0 


0-8 


4-1 


18-4 


76-7 



104 DEPOSITS CULRBYING ALUMINA A3TD SILICA. 

' The mineral assemblages of certain of the deposits include well- 
Tounded grains of heavy minerals. Among the species noted were 
anatase, apatite, cassiterite, epidote, rutile, spinel, staurolite, and 
zircon. 



Deposits in North Wales. 

Similar materials, but more siliceous and apparently derived 
also from Millstone Grit or Carboniferous sandstones which 
have long since been worn away, occur in the surface of the 
Carboniferous Limestone areas of Flintshire (Haliyn, Rhes y cae, 
Pant du, etc.), Denbighshire (near Llandudno and Afoergele), and 
Carnarvonshire (Conway, etc.). Analyses of some of these 
deposits are given in the Tables on pages 157 and 164. With the 
possible exception of Abergele, they are of small extent and for the 
most part not now worked. 

In the recent quarrying of the limestone at Kinmel Park Camp, 
near Abergele, a fair amount of this material seems to have been 
exposed. The quarry, however, has since been partly filled in, and 
little can be seen except clayey matter which is reminiscent of the 
Derbyshire deposits and may be derived from the Trias. Indications 
.are seen all over the area of similar deposits and of likely hollows, 
.and explorations might reveal supplies of . valuable refractory 
materials. The white sand from Abergele (Kinmel Park) forwarded 
to the writer by Mr. E. D. Griffith of Bethesda, is rather sugary in 
character, containing many compound grains. It may have been 
derived from the Millstone Grit, and is much less aluminous than 
most of the other deposits mentioned. Its chemical composition 
is : 

Si0 3 99-35 per oent. 

ALA 0-54 

Fe 2 3 0-04 

loss on ignition .- 0'36 



Total 100-29 per cent 

Alkalies and alkaline earths not determined ; probably absent. 

It is of a good white colour and does not change on ignition. 
The mechanical analysis indicates that treatment by washing and 
screening would improve it : 

>1 mm., 2-6 % j >0'5 & <1 mm., 8'8 % ; >0-25 & <0'5, 77'7 % ; >0-1 & 
<0-25, 8-6 % ; >0-01 A <0'1, 2'3 % ; <0'01, none. Total sand-grade, 
> 0-1 mm., 97-7%. 

BCS OS _MS_ FS ' _s_ _c_ S ."I 
6 ' 8-6' 77-7' 8-8' 2-3' O'O ' 97'7 J 

The detrital mineral residue is very small in amount (O'Ol 
per cent.) and shows the presence of minute zircons and rutiles 



SANDS FEOM MtJETH WALES. 105 

(0'02 to 0'05 mm. in diameter), ihnenite and limonite, anatase, and 
muscovite flakes (0'4 mm. diameter). 

Without further exploratory work, no opinion can be given as to 
the available resources. In any case, the material has no great 
areal extent; it merely occupies hollows and cracks in the 
Carboniferous Limestone. 



106 SILICEOUS HOCKS BEABIN-G ALUMINA AND POTASH. 



OHAPTEK IX. 

BEITISH RESOURCES or BOCKS USED IN GLASS-MAKING 
(FELSPABS, ETC.). 

SILICEOUS BOCKS BEABLN& ALUMINA AND POTASII. 

Although large quantities of rocks rich in alumina and silica 
occur in the British Isles, few contain little or no ferruginous 
material. The otherwise pure felsites and rhyolites are open to 
this objection. The chief rocks, therefore, which may be of value 
to the glftss-manufacturer are pegmatites, aplites, rniorogranites, 
and modified granites free from iron-bearing minerals. Some 
likely-looking rocks were analysed and yielded the following 
results : 

(1) (2) (3) 

SiO, 80-12 82-88 78-84 per cent. 

ALA 10-68 9-39 10-50 

0-14 
0-26 
0-33 
0-20 
0-07 
8-65 
0-41 
0-03 
0-02 
0-57 
0-10 
trace 
none 
n. d, 
0-23 



TiO a 


-0-09 


0-15 


,PeO 


0-49 


0-56 


Ee 


0-06 


0*22 


Oab' 


1-01 


0-09 


MgO 


0-63 


0-20 


K a O 


1-42 


1-88 


Na a O 


3-44 


3-98 


BaO 


0-01 


trace 


MnO 


0-05 


0-01 


H 3 0+ 


0-80 


0-48 


H 2 0- 
00, 


0-28 
1-20 


0-13 
01.., trace 


P a O B 


trace 


none 


ZrO 2 


0-03 


0-02 


S 


0-09 


none 




100-40 


99-99 


Leas f or S , . , , 


0-03 


' 



100-35 per cent. 
08 



Total 100-87 100-27 per cent. 

(1) Granophyre from Brandy Gill (Carrook Pell Syndicate Co.). 

(2) Pelsite from Wioklow, H. 5. 

(3) Tramore (Waterford), C 2. 

Other partial analyses are given in Table III. page 168. These- 
analyses are given as fairly typical examples of what may be 
expected, so far as glass-making is concerned, in rooks of this, 
character. The iron-content is too high for good glass-making. 

The best and most accessible British rocks of this kind 
(pegmatites, aplites, etc.) are mentioned below. They generally 
occur as dykes, that is, more or less narrow parallel-sided sheets of 
rock intruded into other rocks, usually standing almost vertically.. 
The outcrop of such rocks at the surface is rarely more than 



CORNISH FELSPARS. 107" 

a hundred yards wide, and is often only a few feet, but it may 
be of considerable length, and the rock may extend to a great 
depth. 

The pegmatites consist mainly of quartz and felspar crystallized 
together. The felspar may contain potash, soda, and lime. Those- 
rocks which bear potash are most in demand by the potter and 
glass-manufacturer, and have therefore been investigated more- 
fully. 

Felspar is chiefly used in the glass- industry of this country in- 
the manufacture el chemical ware, being imported for the purpose- 
from Norway and Sweden. Owing to the fact that felspar is- 
usually delivered in the form of either pegmatite or graphic granite,, 
the exact composition of the rock is always liable to vary in 
successive consignments. The use of kaolin (china-clay) is open 
to the same objection, but to a smaller degree. For the best 
qualities including optical glass, where, however, the requirements- 
of raw materials other than sand are relatively small in amount, it 
is found advisable to add the soda, potash, lime and alumina, in a 
form of purity and in the required proportions. For second-grade- 
glass-ware, the use of felspar is a convenient and cheap means of 
adding both potash and alumina. Care must be taken, of course, to- 
ensure that the iron-content of the felspar-rock is low (as it is 
in many British pegmatites). Little use is made of felspar at the- 
present time in the bottle-trade. As already mentioned, the 
requisite alumina-content is obtained in rough work by the addition, 
to the batch of brick, baked clay, or even raw ball-clay. For flint- 
glass bottles, pale bottles, etc., where strengthening and toughening 1 
are required, china-clay is sometimes used. British felspars, if 
properly worked, should be cheaper to procure than foreign material, 
and might be used with advantage much more extensively. 

Potash. Felspars. 

The chief potash-bearing felspars which occur in Great Britain' 
(but not in Ireland) have already been dealt with in one of the- 
Special Eesources Memoirs of H.M. Geological Survey*, recently 
issued. One at least of .those described, besides others not mentioned, 
are at present being worked. 

The following account includes notes on Koche felspar additional 
to those published. 

Felspar from the old quarry of Tresayes, near Koche r 
Cornwall. 

The following description of the deposit is given in the Memoir 
of the Geological Survey upon Bodmin and St. Austell, 1909- 
(pages 61, 62) : 

" At Tresayes Downs there is a wide extremely coarse pegmatite 
vein in the Killas a few yards from the margin of the granite. It 

* " Special Reports on the Mineral Besouroea of Great Britain. Yol. T. 
Potash. Felspar, etc." Mem. Geol. Survey, 1916. 



108 SILICEOUS HOCKS BEAHING ALUMINA. AND POTASH. 

consists mainly of enormous orthoclase crystals, 'roughly parallel 
and arranged vertically, some of which are graphically intergrown 
with quartz. Some quartz occurs interstitially, frequently asso- 
ciated with tourmaline and a little fluorspar. There is also a little 
pale mica. The vein has a north and south direction nearly 
parallel with the margin of the granite at this pkce, and is nearly 
50 yards in width. The vein was formerly worked for felspar for 
use in glass-making, but the work was abandoned about 1880." 

Some half-a-dozen trial holes have recently been put down and 
the rock proved over an area one hundred yards long by fifty yards 
wide. At the time of the writer's visit, the pegmatite was visible 
in the old quarry to a depth of about ten feet, the bottom being 
occupied by water. The pegmatite is rather iron-stained along 
joint-planes and contains crystals of tourmaline. For glass and 
pottery purposes, the felspar is hand-picked. The best means of 
transport is down the small valley to Carbis siding. A mineral line 
already extends almost up to the quarry, which at the time of 
writing has once more been opened up. Good-quality felspar is 
being extracted. 

The f ollowing are analyses of Roche felspar : 

(1) ' (2) - (3) (4) 

SiO, 65-00 65-33 62*98 64-21 per cent. 

AljO., 19-00 19-16 18-92 19-66 

Pe^Oa 0-50 0'50 1-18 0-18 

CaO 1-57 1-68 0-75 0'35 

MgO tr. tr. 0-36 0-07 

K 2 10-87 10-37 11-68 12-35 

Na,0 2-40 2-40 4-18 2-79 

H 2 0-83 0-50 0-30 0-73 



Totals... 99-67 99'94 100-35 100-34 per cent. 

(1) & (2) J. A. Phillips, Phil. Mag. Feb. 1871. 
(3) W. Orossley, 281 Dunstan's HU, E.G. 

(4) Dr. H. P. Harwood. Analysed -with especial regard to gla.BH.Tna.1rmg 
requirements. No titanium or barium was present. 

'The quantity of iron in (3) may be due to included tourmaline 
crystals. 

The chemical analysis (4) corresponds to the 'following approxi- 
mate mineral composition (percentage weights by calculation) : 

Potash-felspar 73'18 per cent. 

Albite (soda-felspar) 28-67 

96-85 
Remainder (mainly quartz) . . . 3-49 



Total 100-34 per cent . 

Other dykes of pegmatite are now being opened up at Kemick, 
near Trevisco, and on Trelavour Downs. Chemical and mineral 
analyses of these deposits will be found in Table IV., page 160, 



SCOTTISH FELSPABS. 109 

Felspar from Pegmatites occurring in Scotland. 

A fairly full account of the most accessible pegmatite veins in 
Scotland has been given in the memoir cited*. The veins at three 
localities (1) between Lochs Laxford and Inchard, (2) between 
Durness and Eriboll, and (3) at Overscaig, Loch Shin, are described 
in detail with accompanying sketch-maps for the first and second 
localities. The veins at the first two places occur in the Lewisian 
G-neiss in the extreme north-west of Scotland, where the working 
conditions and questions of transport leave much to be desired. 
The Overscaig pegmatite occurs in the Moine Schists and is also 
difficult to work from rail or boat. The estimated resources 
from the most accessible veins at the first locality mentioned are 
not less than 190,000 tons. At the second locality, not less than 
twelve million tons of pegmatite are available. 

A chemical analysis of the rock from the third locality is given 
as follows : 

Si0.j 72-94 per oent. 

ALfl, 14-26 

TiO a 0-06 

FeA 0-21 

FeO 0-22 

(CoNi)O nt.f<L 

OaO 0-23 

MgO 0-08 

E 2 7-42 

Na a O 3-49 

Li 2 trace 

BaO 0-25 

H.,Oatl05C 0-05 

H a O above 105 C. ... 0-17 

P a O, 0-49 

MnO 0-11 

FeS. nt.fd. 

C0 a " 0-06 

Total 100-04 per oent. 

E. G. Eadley (Anal.). 

Calculation from this analysis gives (percentages by weight) : 

Miorocline 43-96 

Albite 29-61 



Felspar 73-57 

Minor Constituents . . . 2*38 

Quartz 24-09 by difference. 



Total 100-04 per cent. 

Chemical analyses carried out by Dr. Harwood, with especial 
reference to the requirements of the glass-industry, of samples of 

* " Special Reports on the Mineral Besourees of Great Britain. Vol. v. 
Potash Felspar, etc." Mem. Geol. Survey, 1916. 



110 SILICEOUS BOCKS JBEAltlira ALUMINA AND POTASH. 

Scottish pegmatites collected by the writer may be added for 
comparison : 

(1) (2) (3) 

Bi0. 2 69-05 71-53 70-36 per cent. 

Al,O 3 16-84 15-33 15-97 

Ti6 2 none trace none 

IV> 3 0-07 0-05 0-08 

CaO 0-21 0-28 0'12 

MgO 0-06 0-15 0-08 

Z a O 10-08 10-43 10-42 

Na,0 2-83 1-91 2-19 

BaO 0-12 0-60 0'53 

Loss on ignition 0-42 0-21 0*29 



Totals 99-68 100-49 100-04 per cent. 

(1) From the exposure on the shore of Loch Shin, a little more than 

600 yards south-east from Overscaig Farm. 

(2) From a vein 300 yards north of Badcall Pier, about a mile north-west 
from Laxford Bridge, Sutherlandshire. 

(3) From a thick belt of veins on the north-west slope of Beinn Oeannabeinne , 

near Durness, close to locality A of the sketch-map in the Beport on 
Potash-Felspar by H.M. Geological Survey. 

The approximate mineral composition of each sample calculated 
from these analyses is : 

(1) '(2) (3) 

Potash felspar 59'71 61-80 61-74 per cent. 

Albite (soda-felspar) 24-01 16'20 18-58 

83-72 78-00 80-32 
Quartz and other constituents... 15'96* 22-49* 19-72* by difference. 



Totals 99-68 100-49 100-04 per cent. 

The following note t as to the composition of the Scottish 
pegmatite veins is of importance to glass-manufacturers : 

" The pegmatite material consists predominantly of quartz and 
felspar. Iron -bearing minerals, such as .biotite and hornblende, 
are present, but generally constitute less than 1 or 2 per cent., and 
though the proportion may sometimes reach 5 per cent., it is only 
in certain infrequent bands. Where the pegmatites are un crushed, 
these ferromagueskn minerals (which tend to be associated with 
the plagioclase felspars) could be hand-picked from the quarried 
material." 

, [Such iron-bearing minerals as biotite and hornblende are very 
undesirable in felspars used for glass-making. The iron-percentage 
in the analysis quoted above (FeO+Fe 3 3 , 0;43 per cent.) is too 
high for good glass-making. 

f - * The content of barium felspar (celsian) in 1, 2, and 8 is 0-48 %, 2-42 / 
mid. 2-14 % respectively. The remaining minor constituents are small in 
amount. 

f "Special Reports on the Mineral Eesouroes of Great Britain. Vol. v. 
Potash Felspar, etc." Mem. Geol. Survey, 1916, p. 9. 



IRISH FELSPARS. Ill 

The average mineral composition of the pegmatites is said to 
be : quartz 24-8, and f elspai 1 75'2 per cent. Figures in particular 
analyses vary between the extremes : quartz 17*65, and felspar 
82'35 per cent. ; quartz 39'0, and felspar 61'0 per cent. 

The average value for the potash-percentage in the Sutherland 
felspar is stated by H.M. Geological Survey to be 12-81, which 
agrees closely with that of felspar from other localities. The 
potash-content of the pegmatites would, thus amount to about 
9'2 'per cent., which is in accord with the results of the analyses 
made by the Survey. 

For the following notes, published by permission of the Director 
of the Geological Survey of Ireland, on the Belleek felspar, the 
writer is indebted to Mr. W. B. Wright, B.A., F.G.S : 

The Pegmatite Deposits of Belleek, Co. Fermanagh. 

" The felspar deposits of Belleek, the presence of which in the 
district was one of the inducements which led to the establishment 
of the Belleek Pottery, occur in the area of gneissose rocks to the 
north of Belleek and Caatlecalclwell. They are not, however, 
exploited at the present time, because the requirements of the 
Pottery are so small that it would not pay anyone to mine for the 
purpose of supplying this demand alone, as long as materials can 
be obtained from Norway at prices which are reasonable. The 
Manager of the pottery states that from his point of view there is 
little to choose between the native felspar and that which is now 
imported. 

" The felspar occurs as the main constituent of pegmatite dykes, 
which are found traversing the gneissose rocks. It is, to a varying 
extent, graphically intergrown with quartz, and in some places 
penetrated by coarser veins of quartz. White mica also occurs 
here and there as an impurity. 

" The following are the localities (as far as they could be ascer- 
tained by local enquiry extending over two days) in which attempts 
have been made in the past to test the extent and quality of the 
felspar-bearing veins. 

" (1) Townland of Derryrona Glebe, north of Lough Scolban, 
and three and a half miles E.N.E. of Belleek. The pit is now 
filled tip, but the vein is reported by a local farmer to have been 
four feet wide. There is a heap of felspar containing about three 
tons beside the pit. It is graphically intergrown with quartz. in 
the proportion of say one part of quartz to three or four parts of 
felspar. The felspar crystals are sometimes as much as 18 inches 
square. 

" (2) Townland of Scardans Lower, two miles north of Castle- 
caldwell. The vein appears to bo about 4 feet wide and the shaft 
that has been sunk in it is reported to be about 30 feet deep. The 
felspar got out here is not so pink as elsewhere. The crystals are 
up to a foot in length. There is, if anything, less graphically 



112 SILICEOUS BOCKS BEABIKG ALUMINA AND POTASH. 

intergrown quartz than at Lough Scolban. The vein is said to 
have a definite wall and to part easily from it. 

"In this townland there are several other localities where felspar 
can be seen exposed at the surface, or where the local farmers state 
that explorations have been carried out in the past. 

" (3) Townland of Larkhill, in the bog to the north of Croagh 
More, a vein has been opened up in this locality running N. 35 E., 
and dipping N.W. at 50 or 60 degrees. It appeal's to be 4 or 5 
feet thick and was excavated to a depth of about 20 feet at the 
N.E. end. There is a heap of about 20 tons at one side. It 
varies greatly in quality and in its quartz content, which seems to 
be somewhat greater than at localities (1) and (2). 

" There have been some other minor openings in the same 
townland. 

" (4) On the moorland between Loughs TTnshin and Columb- 
kille, about a quarter of a mile S.W. of Lough Unshin and two 
and a half miles north of Belleek there is a nine-foot vein of 
pegmatite running "W. 35 N. and traceable for about 50 yards. 
Only surface quarrying has been done on this vein. It varies a 
good deal in quality. In some places it contains a fair amount 
of quartz and mica, but in others it is almost entirely composed of 
large felspar crystals with minute graphic intergrowth of quartz. 

"The localities numbered (1) to (4) are, as regards size and 
content of the veins, the best which are at present known in the 
district. Veins up to two feet in thickness occur in many places, 
as for example at Grarvary, near Castlecaldwell, where several 
openings have been made. These, however, are hardly worth 
considering until it is known that the larger veins could be made 
to pay. 

"As regards the continuity, laterally and in depth, of these 
veins or dykes of pegmatite, it is impossible to make any confident 
statement, as the country in which they occur is so much obscured 
by drift and bog. Smaller veins in better exposed ground are seen 
to be fairly continuous for considerable distances but vary much 
in width. There ought to be about the same ease or difficulty in 
following them as there is in following an ordinary lode, and they 
have about the same chance of maintaining their width. 

" From the nature of the rocks and the reports regarding the 
shafts already sunk, it is not anticipated that any difficulty would 
arise from water in the mines. A certain amount of felspar could 
undoubtedly be got out by surface quarrying, but in the end 
mining would have to be resorted to. 

" The following are distances from the railway : 

" Locality (1). 1 mile from Castlecaldwell Station. 

(2) & (3). Lmile from rail, 2 miles from Castlecald- 
well Station. 
(4). 2 miles from Belleek Station. 

" The railway freight for coal from Londonderry to Belleek is 



IBISH FELSPAB.8. 



113 



4s. 6d. a ton. The harbour at Ballyshannon is difficult of navi- 
gation." 

Chemical analyses of the Belleek Pegmatite (by Dr. H. F. Har- 
wood and Mr. A. A. Eldridge) are as follows : 

Locality (1) 

SiO, 73-18 

AlA 14-58 

TiO. 2 , none 

Fe.,0 3 0-06 

CaO 0-22 

MgO 0-08 

K 2 10-48 

Na a O 1-52 

BaO trace 

Loss on ignition 0-27 



(2) 


(3) 


(4) 


73-07 


65-74 


70-96 per cent. 


14-71 


18-36 


15-53 


none 


none 


none 


0-05 


0-06 


0-27 


0-22 


0-21 


0-28 


0-05 


0-13 


0-07 


10-14 


13-08 


10-95 


1-60 


2-07 


1-55 


0-02 


0-03 


0-16 


0-46 


0-25 


0-48 



Totals 100-39 100-32 99'93 100-25 per cent. 

The approximate mineral composition of each sample calculated 
from these analyses is : 

(1) (2) (3) (4) 

60-07 77-49 64-90 per cent. 
13-57 17-56 13-15 



Potash felspar ..................... 62-10 

Albite (soda-felspar) ............ 12'89 



74-99 
Quartz and minor constituents 25"40 



73-64 
26-68 



95-05 
4-88 



78-05 
22-20 



Totals ............ 100-39 100-32 99-93 100-25 per cent- 

A few other workable veins of pegmatite were also visited in 
this area by the writer. A chemical analysis of rock from Garvary 
Wood is given in Table IV. page 160. At a very conservative- 
estimate many thousands of tons occur. On the whole, these Irish 
deposits are more easy of access than the Scottish and seem to have 
less quartz intergrown with the felspar ; their soda-content is also 
less. Occasionally stringers of ferromagnesian minerals are met 
with, as in the Scottish pegmatites, but hand-picking will generally 
remove these. 

At Ballymanns, near Aughrim (Co..Wicklow), felspar was said 
locally to have been worked and used in glass-making or pottery 
work. Prof. Grenville A. J. Cole, F.B.S., Director of the Geological 
Survey of Ireland, has kindly examined G. H. Kinahan's field-maps 
for the writer, and finds upon them dykes (running from north- 
east to south-west) of quartz-felspar rook at Ballymanus. Working, 
except for the granite, has been given up for a long time. 

In point of bulk the Scottish deposits stand first, but their 
relative inaccessibility reduces the value of the large resources 
present. The Cornish pegmatites are very limited in quantity, and 
are liable to contain tourmaline. The chief iron-bearing mineral in 
the pre- Cambrian pegmatites is biotite. Other occurrences of 



114 SILICEOUS ROCKS BEAMING ALUMINA AND POTASH. 

felspars in Argyllshire, Co. Donegal (Fintown, Dooey, Glenties, and 
Q-weebarra), and Co. Mayo (Belmullet, Ems Head, Doolough, etc.) 
have heen visited and their workability is being considered. They 
will shortly be described in detail* ; in the meantime, chemical and 
mineral analyses are given in Table IV. page 160. 

For comparison with the analyses of English, Scotch, and Irish 
felspars, may be quoted that of one of the Swedish felspars 
imported in large quantities for glass-making and pottery 
purposes t- 

SMX ........................ 65-78 per cent. 

19-01 



TiOj ..................... none 

Ee.,0, ..................... 0-23 

CaO.' ....................... 0-27 

MgO .................... 0-28 

K 2 ........................ 11-01 

Na 2 ..................... 2-21 

Loss on ignition ......... 0-36 



Total 99-10 per cent. 

The Scandinavian felspar at present in use at the Belleek Pottery 
"has the following composition (H. F. H. & A. A. E.) : 

Si0 9 65-60 per cent. 

AlA 19-05 

TiO a none 

Fe 2 3 0-02 

CaO 0-26 

MgO trace 

K a O 12-12 

Na a O 3-08 

Loss on ignition 0-28 



Total 100-41 per cent. 

Analyses of " Mixed Stone " and " Purple Stone " are also 
given : 

Mixed Stone. Purple Stone. 

SiO a 72-15 70-31 per cent. 

ALO 3 16-28 16-62 

TiO 2 0-20 0-17 

Fe 2 O, 1-45 FeO 1-50 

MgO 0-20 0-08 

CaO 1'65 1-50 

K a O 5-01 5-69 

Na a O 1-50 2-62 

LOBS on ignition ... 1'15 1-25 



Totals 99-59 99-74 per cent. 

* An account is being published by the writer in the Trans. Soo. of Glass 
Technology, vol. ii. (1918). Dr. A. Campbell has recently dealt with further 
Scottish resources in a paper before the Edinburgh Geological Society 
(Jan. 1918). Additional supplies have since been discovered and will shortly 
be described. 

t Trans. Ceramic Soo. vol. rii. (1912-13) p. 65. 



MELDON HOCK. , 115 

With these may be compared the analyses made by Dr. H. F. 
Harwood of china-stone from the West of England China Stone 
A Clay Company Ltd., St. Austell : 

SiO a 75-23 per cent. 

Al.,0., 14-27 

Fe,0 3 0-08 

Cab 1-64 

MgO 0-20 

K.0 4-35 

Na.,0 ' 2-81 

Loas on ignition 1-44 



Total 100-02 per oent. 

Duplicate determination of SiO.,, 75-19 per cent. 

This rock is crushed and ground to a fine powder in the works 
at Par, and is sent to the Potteries. The analyses are quoted as 
indicating that china-stone and related material, if they can be 
secured free from, or with a low percentage of, iron oxide, may be 
of considerable value to the glass-trade as sources of alumina and 
silica, and at times also of potash. 

The British resources of china-stone have been fully dealt with 
in the Memoir quoted above (" A Handbook to the Collection of 
Kaolin, China-clay, and China-stone in the Museum of Practical 
Geology," Mem. Geol. Survey, 1914). 

The following rock is of a similar character :- - 

Meldon Rock and "Sand." ("Devonshire Hard Purple 
Stone.") 

Worked by the Meldon Valleys Co., c/o Messrs. Fox, Eoy, & 
Company Ltd., Plymouth. 

Maps. Geological : Old Series, 1-inch, Sheet 25. 
6-inch, Devon, Sheet 76 S.E. 

Situation. Lat. 50 43' 0", Long. 4 1' 50" W. 

The quarries occur about half a mile east-north-east of Meldon 
Church and near the viaduct of the L. & S.W. Railway, about 
four miles south-west of Okehampton. 

Formation. Aplite dyke intrusive into Culm Shales (Carboni- 
ferous). 

Description. The rock occurs as a broad dyke running roughly 
parallel with the edge of the Dartmoor Granite, and separated 
from it by an outcrop of Carboniferous (Culm) Shales about sixty 
feet or more broad. The rock is a fine-grained aplite, varying 
1 in colour from grey to pale purple. One band runs very true to 
sample, and the good conditions of quarrying, the water-power 
present, and proximity of the L. & S.W. Railway, permit profitable 
working and crushing. Water-power and therefore electric-power 
being available, it is possible that at some later date, if the market 
permits it, washing, screening, and also electromagnetic treatment 
will be instituted to grade the product and free it from some of 
nts iron. 

i2 



116 ' SILICEOUS BOCKS BEABING ALUMINA AND POTASH. 

A chemical analysis of the rock is as follows : 

Si0 2 71-07 per cent. 

AU> 3 16-79 

TiOj 0-06 

Fe a O, 0-27 

CaO 0-87 

MgO 0-05 

K 2 3-83 

Na. 2 4-92 

01 trace 

Loss on ignition 1-87 



Total 99-73 per cent. 

Duplicate determination of Si0 2 gave 70-98 per cent., and of K^O, 
3-81 per cent. 

The iron-content of a sample of the crushed hut untreated 
product is 0-15 per cent. FeO (Fe a O a absent). 

The mechanical analysis of the crushed product is as follows, 
tut it should be mentioned that no attempt has yet heen made 
commercially to grade the " sand." 

>2 mm., 24-6 % ; >1 mm. & <2 mm., 18-5 % ; >0'5 & <1 mm., lO'l % ; 
>0'25 & <0'5, 20-2 % ; >0'1 & <0'25, 12'5 % ; >0'01 & <0-I, 8'2 % ; 
<0-01, 5-9 %. Total sand-grade, >0'1 mm,, 85-9 %. 

F VCS OS_ MS _FS _s ^ G&S -i 
L24-6' 18-5' 10-1' 20-2' 12-5 ' 8-2 ' 5-9 ; 85'9 J 

The mineral assemblage in the rock is a full and interesting one. 
Apart from the minerals occasionally occurring in veins, etc. 
(axinite, green tourmaline, lithionite, fluor-spar, etc.), separation 
with bromoform enabled the following to he identified : greenish 
and pale yellowish tourmaline, purple to colourless fluor, topaz, 
ilmenite, zircon in very small grains, muscovite, etc. 

The crushing strength is 24,100 Ibs. per square inch. 
,.- The rock may be valuable for the alumina it contains and also 
for the proportion of potash. For hottle-glass, the addition of 
limestone and alkali only is required. The rock is at present 
worked for pottery purposes, the crushed material "being supplied 
at 15s. per ton. The freight to Staffordshire is now about 19s. 
per ton ; before the war it was about lls. The available resources 
are very considerable. 

/ 
Potash-bearing Sands. 

Very few of the minerals which occur in sands or racks carry 
potash. The felspars have already been mentioned. Muscovite, 
or potash-mica, rarely occurs in quantity in Britain. As a partial 
decomposition product of felspar (of which the final stage is repre- 
sented by the formation of kaolin), it occurs in the "micas" of 
the china-clay works (see page 100 for analysis, etc.). The amount 
of f erruginous impurity in these " micas " almost prohibits their 
use for glass-making. The only other potash-bearing mineral of 



G-LAUCONITIC SANDS. 



117 



anything like common occurrence is glauconite, which is a silicate of 
iron, aluminium, and potassium. It lias been used as a fertilizer 
because of its potash-content, and it is also of service for softening 
water. The mineral varies in colour from olive and deep bluish- 
green to such pale tints as to be practically colourless. It does not 
Appear to have a fixed chemical constitution indeed, the term 
probably includes a number of minerals of similar composition, but 
with varying quantities of iron, potash, soda, etc. Being an iron- 
bearing material, it cannot be utilized directly in glass-manu- 
facture. Chemical analyses of some samples of glauconite are as 
follows : 



(1) 

SiO, 49-42 

Al a 3 10-23 

Pe a 3 16-01 

PeO 3-00 

MgO 3-78 

CaO 0-31 

K a O 7-91 

Na-O 0-26 

H.,6 8-08 



P,0< 



Totals 99-00 



(2) 

50-42 
4-79 

19-90 
5-96 
2-28 
3-21 
7-87 
0-21 
5-28 
tr. 

99-92 



(3) 
46-91 per cent. 

7-04 
23-06 

2*64 

4-40 

2-95 

7-31 

0-91 

4-71 



99-93 per cent. 



(1) Borne. 

(2) A Continental Q-lauoonite. 

(3) Channel Islands. 



Some highly glauconitic deep green Br 
following composition : 

(1) 
SiC^ 60-61 


itish sands have the 

(2) 
44-76 per cent. 
5-02 
0-45 
9-21 
2-05 
14-56 
2-20 
4-40 
0-09 
0-02 
.. 3-24 
.. 2-48 
.. 10-64 
.. 0-07 
. trace 


ALO n 


9-73 


H 2 0+ . 
H,0- . 
C6 a .... 
MnO .... 
01 


TiO 2 


0-70 


Pe,,0, 


9-67 


PeO 


0-45 


CaO 


1-22 


MeO 


1-89 


K,O 


2-98 


Na a O 


0-83 


P.O. 


0-13 






BaO 


. trace 



ices on ignition 12*38 



Totals: 100-09 



99-79 per cent. 



(1) Prom the Thanet Beds at Bramford, near Ipswich. 
{2) Prom the Upper Greensand, Coffin Glen, Belfast. 



118 SILICEOUS HOCK8 BEA.BING ALUMIXTA AND L'OTASII. 

The potash-content of other British glauconites will be found 
in the Table on page 169. 

It may be possible in the future to utilize glauconite as a source 
of potash, but no British deposits yet found cany sufficient of that 
compound. A satisfactory chemical process must first be devised 
and made commercial. Although the potash-percentage is lower 
than in potash-felspar, the supplies of glauconite are large and 
widely distributed. 

Numerous processes have been worked out for extracting the 
potash from felspar. A summary of some of these is given in the 
" Special Reports on the Mineral Resources of Great Britain. Vol. v. 
Potash-Felspar, etc." an account similar to that in the Mineral 
Resources .Reports of the United States Geological Survey. "Refer- 
ence may also be made to " The World's Supply of Potash," BulL 
Imperial Institute, 1915. A modification of earlier processes lias 
been suggested by E. A. Ashcroft (lust. Mining & Motall. Doc. 
1917). One of the most promising and interesting of rc-cout 
processes is that suggested by Frasser, Holland, and Miller (Journ. 
Indust. &Bngin. Chemistry, vol. ix. No. 10, page 985, Oct. 1917) j 
it aims at producing aluminium sulphate, with potash us a. by- 
product. 

The results on British felspars of procedure patented by Mr. J. 
Rhodin were given in the ' Journal of the Board of Agriculture ' 
for February 1917 (Br. Pat. 13,448 of 1914, 21,097 of 1911, and 
16,780 of 1899). 



TBEATMEHT OF SANDS AND BOOKS. 119 



CBCAPTER X. 

SPECIAL TREATMENT or SANDS AND ROOKS. 

Sands, like many other natural products, can be improved by 
washing. If the process is carried out effectively, a third-quality 
sand may be brought up to the rank of second-quality, but it does 
not produce, in the case of most British samples, a first-quality 
glass-sand. Moreover, the question of extra expense due to washing 
(and sometimes drying also) and consequent additional handling 
and movement, is here an important factor, since very large quantities 
of second- and third-rate sands are used for making glass for lamp- 
chimneys, electric -light globes, flint-glass bottles, window-glass, 
commoner table-ware, etc., individual firms each using as much a 
three hundred tons of sand a week. 

Colour of Glass-Sands Although in the field a considerable 
number of sands appear by comparison to be white, it is remark- 
able how very few are snow-wliite. The colour is frequently a good 
indication of the relative freedom of the sand from oxide of iron. 
The best English sands are locally white, but usually grey, cream- 
coloured, or faintly yellow or brown. To realize the true colom 1 ,. 
samples may be placed upon white paper or compared with Fon- 
tainebleau sand. Small quantities may also be mounted in clovo 
oil and examined under the microscope, when the faint yellow, 
brown, or grey pellicles of ferruginous material are easily visible. 

A dark colour is not necessarily an indication of much iron ; 
organic matter, which may subsequently be burnt out, produces 
this effect. A pink colour may be due to pink quartz and not to 
iron oxide. Similarly, glass itself may be water- white and brilliant, 
and yet contain no small percentage of iron. 

(a) WasJiing. Hematite-coated grains (like those in Permian 
and Triassic deposits) cannot be cleaned without very great 
difficulty, eveii where the coating is thin and the sand pale-coloured. 
In the case of sand-grains having a thin pellicle of liraonite, 
mere washing by water may improve the quality considerably. 
Seeond-ckss sands from the Lower Greensand of Aylesbury, 
Leighton Buzzard, and King's Lynn have been improved and 
made suitable for flint-glass work in this way, but the results are 
not even then so good as the best of the Aylesbury or Lynn sands 
actually found in the quarries. The best sands are not improved 
in the matter of iron-percentage by washing, but the adoption of 
washing does obviate to a considerable extent the trouble or careful 
selection, and enables variable sands to be profitably exploited. 



120 TBEATMENT OF SANDS AITO BOOKS. 

Apart fi-oin the question of the increased cost of washing, which is 
considerable (at least 6d. per ton, but reaching at times, with the 
extra handling, as much as 2s. 6d. per ton), the expense of drying 
has also to be taken into account. 

The coating of sea-salts around the grains of dune- and shore- 
sands does not appear to be objectionable for glass-making (as it 
is when such sands are used for concrete or for building-purposes), 
similar salts being added in the batch. The sands have the advantage 
of being well-graded (see Table V., page 165) as a result of repeated 
sorting by wind and water, but since their colour is not good and 
they often contain abundant shell-fragments, it is clear that repeated 
washing will not produce purity without the intervention of living 
organisms and percolation of water (c/!, for example, the patchiness 
of colour in the red sands of the Permian and Trias due to reduction 
around organic remains). 

The value and importance of washing must be strongly empha- 
sized. It is satisfactory to note that the producers of sand are now 
becoming alive, under war-conditions, to the improvement thus 
affected in sands and the correspondingly enhanced market value. 
Sands for refractory purposes, as well as glass-making, are now 
being washed in many instances by the producers. Although the 
process is frequently earned out at the sand- quarries, water is not 
always available in the quantities desirable. It will often pay 
glass-manufacturers to wash or re- wash their sand at the works, as 
dirt, dust, etc., are usually picked up during transit. The effect 
of washing is two-fold. It removes much adherent iron oxide, 
calcareous material, etc., and also clay, silt, and fine sandy matter 
which are undesirable in a glass-sand. A comparison of analyses 
of glass-sands before and after washing is of considerable value. 
Improvement will be noted in both grading and chemical 
composition. (See Tables on next page.) 

In this connexion, as indicating the material washed out of a 
glass-sand, it is of interest to quote the following analysis from the 
remarks upon American Glass-sands in Bulletin 285 of the United 
States Geological Survey (page 461) : 

Analysis of a Slime from washings of a sand from Ottawa, 111. 
Si0 2 87-21 per cent. 



Fe 2 a 0-52 

CaO none 

MgO none 

Na.,0 ' 20 



Total 95-43 per cent. 

Bflmainder mainly water. 

This analysis indicates that besides ferruginous and clayey 
matter, much fine silica had also been removed from the sand. 



WASHING OF BANDS. 



121 






5 

& 



B 

a 



5 

O "PO 

^ 8 



!i 


us oo 


OS OS 


-$ 




as m 


OT ls 

H 


O 00 
OS OS 


]> do 

OS OS 


CO -* 
00 OS 


us 00 

OS OS 


CO OS 
OS OS 


*d 


US I> 


00 OS 


OS rH 


OS 00 


OS CO 


y 1 


to o 


O 


M TH 


IM O 





. 
. r " 1 T 1 


O US 


OD N 


TH US 


to us 


00 IN 




CO O 


rH 


do -^ 


TH 





* 


US CO 


rH iH 


CO I> 


O O 




Pq Ai O 


r- -^ 


os eo 

TH 


OS ^ 


a* 


fi CO 


5 


OS 't 


t>- US 


to i> 


r-l OS 


iH CO 


A 


us o 
r- os 


COCO 


lO OS 


TH iH 
t- OS 


us O 
OS OS 


rt2i 


S-S 

TH I> 


TH n 


to . 






AV 


r- N 


OS iH 




^H TH 


o : 


g 1 


^ 










^ A 














Untreated. 
Washed. 


-0 
-? 
J| 

ri ^ 


JH 
3 

fl . 


Untreated. 
Washed. 


Untreated. 
Double washed. 




























r 

o 


ShirdleyHill... 
i> ,, ... 


Port-a-cloy . . . 

. " " '" 


o 

i- 
1 " 


1 = 




122 TREATMENT OP SANDS AND EOCZS. 

A method of washing sand adopted abroad is on the principle of 
acid-scrubbers, the sand being arranged upon tiers of platforms 
above one another and washed by distributed descending sprays of 
water. 

Various methods, including tank-washing, have been adopted in 
this country, but some form of rotary process is most commonly 
used. 

In some cases the sand is washed twice over to ensure better 
cleansing. It is often an advantage, especially when washing is. 
adopted in order to cleanse a sand from iron oxide, to have the- 
cylinder much longer than it usually is. Care should be taken 
to ensure that rotary washing-plant is suited to the grade of the 
sand. If the latter is too fine for the apparatus, much loss will 
result owing to the carrying off of fine sand in the stream of dirty 
water. 

The most efficient machine for washing sand at present in use in 
this country is, in the writer's experience, that devised by Mr. 0. 
Bikof of 159 Pentonville "Rd., London, N. 1. A short description 
may be of use to sand-merchants and gl^ss-manufacturers. 

The Washing and Screening Machine (Eikof's Patent) is 
illustrated in Plato VII. and Fig. 13, and is so designed that it will, 
with small modifications to suit particular cases, wash any material 
from coarse gravel to fine sand. By an automatic feeding device 
the material is delivered into the slightly inclined revolving 
washing cylinder, the feeding being continuous and uniform so that 
all the materials are subjected to an equal amount of washing. 
The machine can therefore be run at maximum output without 
incurring the risk of temporarily overtaxing its capacity, which 
might happen in the case of manual feeding. 

The length of the washing cylinder is fixed in accordance with 
the time required by the water for removing the binding materials 
and for separating the particles from each other. The cylinder is 
divided into sections or compartments so arranged that while the 
washing water overflows from a cleaner compartment into one- 
containing dirtier material, and is finally discharged at the higher 
end of the cylinder, the material travels in the opposite direction 
and is automatically propelled over the partitions, each time 
into a compartment containing cleaner water. Eventually the 
materials are delivered into cylindrical screens, the number and 
fineness of which depend on the grades into which the said 
materials are to be divided. The screens are arranged concen- 
trically, the innermost cylinder having the largest holes. The 
holes in the outermost cylinder determine the largest grains of the 
finest sand. Water-sprays between the screens facilitate the 
screening and subject the particles to a final cleansing. The water 
is led away with the sand into a special sediment separator, which 
constitutes a novelty in sand-washing machines and is necessary 
for securing clean, drained, sand (Fig. 13). This contrivance is 
most simple in construction as well as in working. It consists 
of a steel cone fixed at its larger end on to a wide flange centred 



BIKOP'S WASHING MACHINE. 



123- 



on an almost horizontal slowly revolving shaft. On the outside 
of this cone are numerous vanes or blades forming pockets- 
for receiving the washed sand and the cleansing water. The 
pockets are so arranged that the top edge of each is level when 
reaching the horizontal plane containing the cone axis, and in this* 
position it cuts off the supply of water and sand, which then goes into 
the next pocket. The contents, which during the filling are most 
vigorously agitated, become calm after the supply has ceased, and 

Fig. 13. Cone-attacliment to JtiJcofs Washing Machine, 
fw cleansing and draining Sand. 





the sand settles quickly in the lower portion of -the pocket near the 
flange, the water with the silt in suspension being gradually tilted 
off: at the smaller end of the cone as the latter revolves and the larger 
end of the pocket is elevated over the top of the cone. When 
farther advanced, the sand is discharged at the other side of the 
cone, and the empty pocket proceeds on its way to receive a new 
charge. > 

The efficiency of the machine is dependent on its being worked 
at the proper speed and with a water-supply suiting the nature of 
the materials under treatment. Once carefully studied, however, 



124 TREATMENT OP SANDS ATST) ROCKS. 

and properly adjusted, the machine works automatically and with 
excellent results. 

- The arrangement described above for draining the sand renders 
the question of drying it a much less serious matter. Air-drying 
is usually effective and sufficient. The users of .sand naturally 
prefer it to be delivered in a dry condition, but methods of artificial 
drying are frequently too expensive for the sand-merchant to 
undertake. The transport of perfectly dry sand is also at times a 
troublesome matter. 

Other devices are employed to hasten the drying by draining off 
the water, and sometimes the process is carried out in large ovens 
(two tons at a time), but systematic drying- plant like that used 
in America has not yet been introduced. Drying is carried out in 
the Mississippi valley and other places by the use of tier dryers, 
rotary methods, or steam coils. Small quantities of dry sand are 
frequently required in this country during the winter, for use as 
parting-sand in facing moulds for brick-making, etc. In this case 
a small oven is built of bricks, a fire lighted within it, and the sand 
heaped over and around the oven. 

(b) Screening, etc. In the matter of the improvement of the 
grade of a sand, screening may be combined with washing without 
much difficulty, and clayey and silty materials may be washed out 
by suitably controlled streams of water. If an elutriator is set up 
in the works' laboratory, analysis of the sand or crushed rock will 
give an indication of the velocity of the stream of water which will 
cany off all grades below that desired. For certain gksses it is not 
too expensive to treat local sands on a large scale in water-currents 
adjusted to this determined velocity. The process, in addition, 
will clean the sand of dirt and possibly some iron oxide. A velocity 
of 3 - 5 mm. per sec. (42 feet per hour) is the theoretical velocity 
which will carry away all particles (which can move freely) of 
diameter less than '075 mm. The use of a greater velocity than 
this will be necessary on account of the friction of sluices, etc. and 
the bulk of sand treated. An air-blast may be used, as it is occa- 
sionally in engineering practice or for filtration purposes, to clear 
a sand of fine material. Such a blast of about l - 5 metres per second 
(about 4'9 feet per second) will carry off all particles of diameter 
less than O'l mm. 

The importance of screening sands and crushed rocks to free 
them from coarse grains and fragments which Avould remain 
as undigested " seeds " or " stones " in the glass, has already 
been emphasized. It is frequently of value to fine-screen n 
glass-sand also. Mr. C. J. Peddle, chemist to Messrs. Wood Bros. 
Q-lass-Works of Bamsley, lias demonstrated the improvement in 
the properties of glass-melts made from sands sifted to 80-mesh 
ft)'22 mm.), the portion passing the screens being rejected. The 
reason for this is threefold. Clay and silt are removed as by 
washing. The surface 1 -area of grains increases relatively as they 
decrease in diameter. The grains composing the line grades of a 



SCREENING AND BURNING OF SANDS. 



125 



sand therefore tend to carry a relatively greater proportion of 
ferruginous and clayey coatings. In the third place, the pro- 
portion of heavy detrital , minerals in a sand (including the 
objectionable zircon, rutile, and iron-bearing minerals) rises with 
decrease in grade-size. The following figures* illustrate this, 
point : 

Heavy Minerals in Q-lass-Sanfa. 

Variation with grade of percentage of crop having a density 
greater than 2'8. 





Grade-size in mm. 


0-025-0-05. 


0-05-0-1. 


0-1-0-2. 0-2-0-4. 


Pork Lane Reigtvte 




407 % 
253 
302 
870 
700 
356 


098 % 
191 
050 
230 
060 
098 


014 % 

024 f 
008 


Ashurstwood 


1-26 % 


Longdown 


Denford 




Jarvis Brook, Crowborough . . 









Dry-screening may be adopted to improve the grade and iron- 
content of certain sands, where the coating of the quartz-grains, 
consists of the valuable kaolin and not feme oxide, 

(c) Burning. The better-class sands are undoubtedly improved 
by ignition. Water, often an objectionable constituent, is driven 
ofE. Organic substances are burnt out, and an improvement in 
whiteness results. Impurities which have been introduced during 
transit, e.g., dirt and coal (when the sand is brought back by 
coal-barges as ballast) are eliminated. For very special work, such 
as optical glass or the finest crystal ware, it is advisable to wash 
and burn even a very pure sand like that from Fontainebleau. 

Burning, therefore, cleans a sand if it has been darkened by in- 
cluded peaty matter, but if the discoloration is due to staining by iron 
in a slight degree, the sand becomes a darker grey, brown, pink, 
or red colour, the usual change being that from the hydrated oxide, 
limonite, to the anhydrous oxide, hematite. The effect of burning 
thus yields in most cases a rough indication of the amount of iron 
present as staining, that in the heavy minerals, as already stated, 
usually being of little importance. If the burning is earned on 

* These are a selection from the results of a lengthy series of experiments 
which were carried out by my friend, Mr. Y. C. Tiling, M.A., P.G.S., of the- 
Eoyal School of Mines (Imperial College of Science and Technology), and 
which he kindly permits me to quote. 

f The heavy crop in the grade >0-4 mm. diameter amounted to less than. 
0-001 per cent. 



126 THEATilENT OF SA2O)S AXD DOCKS. 

under standard conditions, the temperature being; recorded by means 
of a pyrometer, and the increase in colour compared with the tint 
of known standard materials, an approximate id^a of the amount 
of iron and organic matter present may be obtained. Most of the 
British deposits under consideration darken on heating, as do also 
the Belgian glass-sands so extensively used in this country. The 
latter are almost white, but attain a slightly pinker colour, while 
Dutch sand becomes greyer. Of the few British deposits which, 
like Fontainebleau sand, show no change on heating, the following 
may be mentioned : the best quality sand from Aylesbury and 
selected Godstone and lieigate sands (Lower Greensancl), sand 
from Muckish Mountain, Co. Donegal, and a sand from Abergele, 
North Wales (the last two contain ferruginous patches which 
darken considerably). Pure white sandstones, such as the Coal- 
Meaeure Sandstone from Ghiiseley, near Leeds, also show no change 
-of colour on heating. 

Many glacial sands appear to be light-coloured and fairly pure, 
but on examination are usually found to contain limonite pellets 
(often representing decomposed iron -bearing minerals). They burn 
up to a much darker colour. 

(d) Qliemieal Methods. Other processes for the purification of 
sand from iron are too costly if any great quantity of the sand ia 
required in industry *. Acids only partiallv clean the sands, even 
with application of heat. Hydrochloric acid has been used in this 
way, but the solution of iron oxide is never complete. By raising 

,a mixture of a sand with about 2J per cent, of common salt to a 
red heat, and afterwards lixiviating with water, complete purifica- 
tion from iron is obtained t- Treatment with sodium hydrosulphide 
is said to yield the same result at lower temperatures. Nitre-cake 
has been successfully used on a small scale for dissolving out 
ferruginous and other compounds from sands. It consists of a 
mixture of acid and neutral sodium sulphates, its bleaching 
properties depending upon the unrecovered free sulphuric acid 
present. Nitre-cake has also been recommended for use in glass- 
making as a partial substitute for potash. A by-product from 
explosive works, it was obtainable before the outbreak of war for 
the mere carrying away from the tips, or for a nominal price of 
I/- per ton. Since 1914 the demand for it has largely increased, 

-owing to the unrecovered acid present, and the price is now 

. about 17/- per ton at the works. 

As an example of what can be done in the way of cleansing 
sand, the following analyses may be quoted. A yellow-brown 

* The largest glass-making firms each use 100,000 to 150,000 tons of sand 
. a year. 

t Patent No. 8495 (1914) by J. G. A. Rhodin, "Improved Means for and 
Process of Bleaching Sand." The same idea was suggested in Bassett's 
patent for the extraction of potash from felspar, U.S. 1913 (see Potash Salts, 
U.S. G. S. Mineral Resources, 1913). 



CHEMICAL AND MAGNETIC METHODS. 



127 



impure Triassic sandstone from EaglesclifPe was treated with 
nitre-cake, and yielded a clean white sand : 

Before treatment : Fe.,0., 0-20 per cent. 

After treatment : Fe^OJ, (a) 0-03, (i) 0-048, (c) 0-045 per cent. 

Analysis of treated sand. 

SiO., 93-59 per cent. 

A1,O 3 3-51 

Fe" 2 3 0-03 

CaO 0-16 

MgO * 0-14 

K.,o 0-94 

Na^O 0-83 

LOBS on ignition 0'66 

Total 99-86 per cent. 

This white sand does not change colour on burning. 

The amount of alumina in this material is noteworthy. The 
product having been well screened and washed, several different- 
sized sands can be supplied. The products are well-graded, as the 
following mechanical analyses indicate : 















| OS. 


MS. 


FS. 


S. 


c. 


S. 


, i >0-5 & 
Sample. |<lmm 

i 


>0-25 & 
<0-5. 


>0-1 & 
<0-25. 


>0-01 & 
<0-1. 


<o-oi 

mm. 


Total 
sand-grade : 
>0-1 mm. 


i ! o-i % 


15-3 % 


82-7 % 


1'5 % 


0-4 % 


98-1 % 


2 i ... 




94-7 


4-2 


1-1 


94-7 


i 













Material of rather coarser grade than this will also be available. 

Sodium carbonate (washing soda) may also be employed for 
cleansing purposes, as the following figures of a sand from Leighton 
Buzzard indicate : 

Before treatment, Fe a O.,, 0'04 per cent. ; after treatment, 0-015 per cent. 

These methods are usually too costly except where pure sand is 
required for very special work, such as optical glass. 

(e) Magnetic Methods. Endeavours to remove objectionable 
heavy minerals from a sand are not, as a rule, paying propositions. 
Electromagnetic methods have, however, been applied in glass-works 
in the United States of America to the freeing of an otherwise 
suitable sand from such iron ores as magnetite. . Separators have 
only been employed where high -class gkss is made, and it is 
claimed that the colour and brilliancy are improved as a result 
of the treatment of the sand. Other iron-bearing minerals 
(including silicates, etc.) less permeable to electromagnetic action 
can at the same time be removed. 

If hard rocks, such as well-cemented sandstones and quartzites, 



12S TKEATMKS'T OF SA2TDS AND BOOKS. 

art- crushed for glass-purposes (see below), magnetic separation 
must be resorted to in order to free the product from frag- 
ments of iron or steel obtained from the rolls or jaws of the 
crushing-plant. The process is similar to that employed in the 
{reparation of raw materials for the manufacture of pottery, .It 
has not been found necessary to apply this treatment to sand 
t btained from soft grits and sandstones. 

As an example illustrating the necessity of electromagnetic 
treatment of the product obtained by crushing a rock, the folio wing- 
may be mentioned : 

West of England China Stone & Clay Company. 
China-stone crushed at Far, Cornwall: 

Product before electromagnetic treatment : Iron estimated as Pe a 3 , 0-12 \>. c. 
after ,. 0-08 p. o. 

About one c\rt. of iron is abstracted Weekly from about fifty tons 
of the crushed rock. 

(For analysis of this china-stone, see page 120.) 

The amount of ferruginous matter introduced by crushing rooks 
may be gauged from the following figures : 

Iron-content estimated as I"e 2 s . 
Westport Silica (vein-quartz from Adhill I.) : 

before crashing, 0'004 per cent, ; omened product, 0-04 per cent. 
Meldon Valley rock (aplite) : 

before crushing, 0'15 per cent. ; crushed product, 0-27 per cent. 

Griadingor Milling. Onlj for the best glasses for optical 
Sa" V^^' * ,?* ^ ^-grind the sand to 1 line 
rt L 5 T^IF and moi>e re S nIar and ^a melting 

W ^ T i\\ * the 6X P ense is ^siderable. The process 
has been adopted in the making of laboratory glass-ware but t i s 
doubtful Aether any great advantage accrues. 5 The procedur s 






eco r ic 

the rock breaks down, of the chie rn^? ?J Pr T Ure 
mended as sources of si^a and al^' ^ ^ been rccom - 
mcidentally for refractoj ^^^oses " ^ 5S ^^S, and 



CRUSHING STRENGTHS. 129 

The crushing strength of pegmatites is very similar to, but 
perhaps rather less than, that of granites, which varies from ahout 
12,000 to 38,000 Ibs. per square inch. An average figure is perhaps 
18,000 Ibs. per square inch. 

Sandstones vaiy very much in their crushing strengths according- 
to the degree of their consolidation and character of the matrix. 
A moderately soft sandstone from Plean, N.B., has a crushing- 
strength of 953 Ibs. per square inch, while a finely-cemented 
quartzite may have a crushing strength of over 30,000 Ibs. per 
square inch. Some sandstones used as building-stones give way at 
less than 3000 Ibs. per square inch. Others withstand successfully 
a pressure of 16,000 Ibs. per square inch. 

The average crushing strengths of some of the rocks which 
have been crushed and put on the market as glass-sands or refractory 
materials are given in the following table. The tests were earned 
out in the Laboratories of the City and Guilds (Engineering) 
College (Imperial College of Science and Technology), with the 
kind co-operation of Prof E. F. D. Witchell, cubes of 2*5 ins. side- 
being used, except where otherwise stated .- 

Spital Sandstone 1,450 Ibs. per square inch (3-inoh cubes) 

MeldonBook 24,100 (3-inoh cubes). 

Stiper Qimrtzite 32,000 

Appin Quartzite 32,200 

Holyhead Quartzite... 30,600 



180 FOBEIGN GLASS-SANDS. 



CHAPTER XI. 

FOREIGN GLASS-SANDS. 

A discussion of suitable British glass-sands would not be 
complete without comparative notes upon some widely-used Con- 
tinental and American examples. Notes upon a few well-known 
foreign glass-sands are therefore appended. 

EUROPEAN SANDS. 
Lippe Sand. 

This sand was imported into Britain before the war for the 
making of silica- ware and certain special varieties of glass ; but 
its use was not extensive. Two different samples of this famous 
glass-sand from DOrentrup, Saxony, were supplied to the writer 
through the kindness of Dr. Walter Rosenhain, F.R.S., Director 
of the Metallurgical Department, National Physical Laboratory, 
Teddington, and were subjected to analysis and examination. 

The sand occurs in deposits of Miocene age, and is associated 
with rafts of braunkohle*. In this connexion it may also be 
noted that the valuable glass-sand of Hohenbocka in Prussia, 
occurring in Miocene strafe, is also associated with carbonaceous 
layers f. 

Both samples of Lippe sand are beautifully white, of better 
colour even than that from Fontainebleau. The better sample is 
finer in grain and remarkably even, while the second is rather 
coarser. The chemical analyses are as follows : 

I. H. 

SiO a 99-88 per cent. 99-73 per oent. 

A1 2 3 0-18 0-20 

Fe a 3 J n.d. n.d. 

Loss on ignition . . . 0*21 0-23 



Totals 100-27 per oent. 100-16 per oent. 



* Jahresb. nieders&onB, geol. Yer, 1910, p. 185 ; and Zeitsohr. deutsoh. 
.geol. Geaellsoh. Band xl., 1888, p. 310. 

f K. Keilhaok, Jahrb. K.-prenss. geol. Landesanat. 1908, Band "rix. pt. ii. 
p. 214. 

J Separate estimation of iron gave : I. 0-02 per oent., II. 0-03 per cent. 
Analyst ; B. Spencer. These values are probably too high. 



LIPPB SAJrt). 131 

It is said that, such is the remarkable constancy of chemical 
purity, the sand is guaranteed when sold to contain 99 '98 per 
cent, of silica. 

The mechanical analysis of the finer and better sample is : 

>0-S & <1 mm., one or two grains; >0-25 & <0'5, 78'6 % ; >0-1 & 
<0-25, 19-9 % ; >0'01 & <0'1, 0'4 % ; <0'01, 1-1 % *. Total eand- 
grade: >0'1 &,<! mm., 98'5 %. 

PCS NS FS _s_ _c S "I 
L tr.' 78-6' 19-9' 0-4' 1-1 5 98-5 'J 

Measurement under the microscope shows that the average dia- 
meter of the grains is O3 mm. (or perhaps slightly less). They 
are composed, with the exception of the tew detrital minerals, of 
colourless clean quartz and a very little felspar, subangular to 
angular in shape. The mechanical analysis (if the second 
sample is : 

>0'5 & <1 mm., 10-2 % ; >0'25 & <0'5, 85'8 % ; >0'1 & <0-25, 1-4 % ; 
>0-01 & <0'1, 1-0 %j <0-01, 1-6 % *. Total sand-grade: >0'1 & 
<1 mm., 97-4 %. 

PCS MS FS ^_ _c _S -1 
LlO'2' 85-8' 1-4' I'O' 1-6 J 97 : 4'J 

The grains, which are subangular, are similar under the micro- 
scope, but are for the most part nearly 0'5 mm. in diameter. 

The heavy residue of minerals was small in each case (less than 
O'Ol per cent, by weight), but, as is often the case, was greater in 
the finer sand than in the coarser. 

The former yielded a pretty residue consisting of abundant zircon 
and red-brown rutile, rather rounded, and averaging 0*12 mm. 
diameter, together with large Icyanite fragments up to 0'7 mm. 
long, and coai-se staurolite and tourmaline grains. The stiiurolite 
is deep golden-brown in colour, of diameter 0'2 to 3 mm. The 
tourmaline occurs in grains up to 0'3 mm. diameter, of brown, 
greyish, greenish blue, and deep blue colour. Magnetite, ilmenite, 
leucoxene (0'2 to O3 mm. diameter), and limonite occur. Small 
.and non-pleochroic dusky grains of andalusite occur less com- 
monly, and chlorite also was seen. 

The second sample yielded a rather coarser residue, consisting of 
.abundant pleochroic andalusite (0'3 mm. diarn.), krge, yellow, 
grey-brown, and greenish tourmaline (O3 mm. diam.), deep green 
hornblende (0'2 mm. long), and ilmenite. Staurolite and zircon 
occurred in small grains 0'05 mm. long. Chalcedony wa,s also 
seen in the sand. 

* Hygroscopic water included. 

K2 



132 



TOBEIGN GLASS-SANDS. 



Fontainefcleau Sand. 

The sand, of Upper Oligocene (Stampian) age and associated 
with lignites *, occurs in considerable quantities at Fontainebleau, 

near Paris. . ... 

The- mechanical and chemical composition are given in the 
Tables, and the general properties are discussed in Chapter V. 

The sand costs upon delivery at British works from 12s. to 39s. 
per ton (rising to 50s. and 60s. through war-difficulties), according 
to distance brought on mil, an average price being 17s. The cost 
lias, of course, increased owing to the war ; and for some time after 
the outbreak of war, as well as again at the time of writing, diffi- 
culties existed, due to shortage of labour and ships, in getting it 
through to England and Scotland. 

Belgian Sand. 

The sands cost, upon delivery in this country, from 4s. to 1G. 
per ton. They often arrive as balkst, packing for bottles, etc. 
Large quantities were sent from the Campine. 

Some of the sands are shipped from Rotterdam, and the unequal 
qualify since the outbreak of war leads to the suspicion that some 
of those now being supplied may be inferior Dutch sands. Much 
variability in tint and slight differences in mechanical composition 
occur (see Tables, pages 166, 167, and Fig. 10, page 50). The sands 
may he almost white, a very pale grey, or a marked pale pink, in 
part due to the presence of pink quartz. Their iron-content is 
slightly greater than that of Fontainebleau sand, and they burn to 
a rather darker pink shade. Washing does not improve the colour 
noticeably. 

One sample from Barnsley Glass-works, which was analysed, 
proved to have the following chemical composition : 

Si0 2 99'38 per cent. 

ALfl n 0-30 

Fe.,0., 0-02 

Losa on ignition 0'28 



Total 99-93 per cent. 

Mechanical analyses show the following grade-proportions : 



- 


CS. 
>0-5 & 
<1 mm. 


MS. 
>0'25 & 
<0-5. 


FS. 
>0-1 & 
<0-25. 


s. 
>0-01 & 
<0-1. 


0. 

<0-01. 


S. 
Total sand-grade : 
>0-1 & <1 mm. 


Knottingley 
Glass-works. 
Barnsley Glass- 
works 


9-6% 
<0-1 


83-3 % 
99-3 


5-9% 
0-3 


1-2% 

fl-4. 


0-0% 

A.A 


98-8 % 














yy G 



TVT * liS^" 1 . 3 * k Fenme de Fontainebleau," Bull. Serv. Carte g<5ol. France, 
No. 122, vol. xuc. (1909) p. 9 ; and numerous other references. 



BELGIAN AND DUTCH .GLASS-SAJfDS. 



133 



Quartz, somewhat rounded to subangular, makes up the bulk o 
the sand, but cleavage-flakes of felspar are to be seen. The heavy 
residue is small, and of the type which in Britain characterizes the 
Pliocene deposits. Among the coarse dense grains are kyanite, 
andalusite, staurolite, rutile, yellow-brown tourmaline,, iron ores, 
etc. 



Dutch Sand. 

The prices of Dutch sand have varied considerably in pre-war 
and present times, the range being from 9s. to 28s. per ton. 

Only a few samples have been analysed. They had a slight 
grey or brown colour, some darker than Belgian sand, and differed 
to some extent in grade-percentage (see Tables, pages 166, 167, and 
Fig. 10, page 50). Occasionally the sand is white and equal in 
quality to that from Fontainebleau. 

The chemical analyses of two samples are as follows : 



Al,0., 

Pe.,0'., . 

CaO ' 

MgO 

LOBS on ignition 



Knottingley 
Glass-works. 
99-23 per cent. 
0-50 
0-02 
n.d. 
n.d. 
0'22 



Edinburgh & Leith 
Glass-works. 
99-63 per cent. 
0-35 
0-03 
0-08 
trace 
0-19 



Totals 99-97 per cent 



100-28 per cent. 



The grading composition is indicated by the following results of 
mechanical analyses : 





OS. 


MS. 


PS. 


B. 


c. 


s. 




>0'5& 


>0-25 & 


>o-i & 


>o-oi & 


<fO-l 


Total sand-grade : 




<1 mm. 


<0-5. 


<0'25. 


<o-i. 


' 


>0-1 mm. 


Knottingley 














Glass-works. 


0-7% 


68-0 % 


30-8 % 


0-5 % 


o-o % 


99-5 % 


York Glass- 














works 


0-4 


93-5 


4-8 


1-3 


o-o 


98-7 

















The heavy crop is a rich and abundant one, consisting of well- 
rounded grains 0'15 to 0-2 mm. diameter. The minerals present, 
besides quartz and felspar, include purple and brown tourmaline, 
epidote, staurolite, kyanite, red gamet, green hornblende, scircor, 
andalusite, muscovite, ilmenite and leucoxene, magnetite, limonite, 
etc. 



134 FOREIGN GLASS-SANDS. 

AMERICAN HIGH-GRADE GLASS-SANDS *. 

For the samples of sands upon which the following descriptions- 
are based, the writer is indebted to Dr. G. Otis Smith, the Director 
of the United States Geological Survey. 

The beauty and high quality of the best American glassware 
have long been known to those concerned with the industry in 
Britain. It may therefore be of interest to give a brief description 
of the best glass-sands produced in the United States. The 
samples were collected by Mr. Ralph W. Stone, whose valuable 
accounts of the American glass-sands and their treatment have 
been of great use to British workers. For additional information, 
therefore, reference should be made to his descriptions of some of 
the sands in Bulletins 285 and 815 of the United States Geological 
Survey and to the Annual Reports on Mineral Resources (e. g., 
1911-15). The following notes are based upon examination of 
the samples supplied, but the accompanying letters from the 
sand-merchants have given information as to the treatment to- 
which the materials have been subjected. 

It will be observed that the crushing, screening, washing, and 
drying of the sands are more carefully and thoroughly carried out 
across the water than here. British glass - manufacturers will 
doubtless note this with interest, and endeavour to impress the 
fact upon the sand-merchant at home. We should remember, 
however, that the American quarrying and treatment are earned 
out upon a large scale and that greater facilities for transport appear 
to exist in the United States than in this country. 

For comparison with British deposits, it is interesting to note 
that the glass-sands are obtained by the treatment of friable sand- 
stones, all of which are of considerable geological age. They 
range from Cambrian quartzite to Carboniferous sandstone. 
Similar materials have been recommended from these islands, 
and the writer has dealt elsewhere with such resources. It is. 
interesting to note, however, that all the best West European 
glass-sands, including many of those from the British Isles, come 
from geological deposits of Tertiary age, /. e., are comparatively 
recent in formation. 

The fact that practically no compound grains are present in 
these American glass-sands points to friability of material and 
care in treatment. All are highly quartzose and none very 
aluminous in character. The alkalies have not been estimated, 
since in most cases they are either absent or exceedingly small in 
amount f. The mineral-content in all the sands is small, and the- 
few detrital minerals are mostly of the common, very stable, type. 
The iron-content throughout is remarkably uniform, and low, 

* This aooonnt is reprinted with slight modifications from the ' Trans- 
actions of the Sooiety of Glass Technology, 1 vol. i. (1917) p. 147, by permission 
of the Council of the Sooiety. 

t All the analyses have been made upon the treated samples aa received. 



SANDS FHOH OTTAWA, ILLINOIS. 185 

namely, about O02 per cent. In some of the sands, such as those 
from the St. Peter's sandstone, the very pure appearance of the sand 
would lead the observer to expect a smaller percentage even than 
this. When the heavy minerals are examined, the reason is clear. 
In these cases, the iron-percentage is due to the authigenous pyrite 
(FeS a ) present. Most of the sands show no change of colour on 
ignition. 

Sufficient material could not be spared for the purpose of working 
out the mineral composition of each sand exhaustively. 

Sand from the Ottawa Silica Company, Ottawa, Illinois. 

The sand is produced by crushing the very friable St. Peter's 
sandstone of Carboniferous age ; the Company state that it lias 
been washed twice, steam-dried, and screened. It is slightly 
greyish in colour, and consists of beautifully rounded grains, a 
few of which are spherical, most being spheroidal. The surfaces 
are in many cases roughened and etched. A few large grains 
occur. 

The chemical analysis quoted by the Company is : 

Si0 2 99-82 per cent. 

Al a O a andFe a O, ... 0-05 
CaOandMgO 0-13 



Total 100-00 per cent. 

and that by Dr. Harwood and Mr. Eldridge : 

Si0 2 99-48 per cent. 

ALO., 0-16 

Ie 2 3 0-02 

CaO 0-11 

MgO 0-05 

Loss on ignition . . . 0-13 



Total 99-95 per oent. 

The mechanical analysis is as follows : 

>1 mm., 0-5 %; > 0-5 & <1 mm., 21-6 %; > 0-25 & < 0-5, 75'6 %; > O'X 
& < 0-25, 1-3 %; > 0-01 & < 0-1, 0-3%; < O'Ol, 0>7 %. Total sand- 
grade, >0-1 mm., 99'0 %. 

rvos cs[ MS FS _s_ _o_ _s -i 

L.0-5' 21-6' 75-6' 1-3' 0-3* 0-7 '' 99'0'J 

The heavy detrital minerals are small in quantity (O02 per 
cent.) and of little interest. Many are well-rounded, blue and 
brown tourmaline, zircon, and large garnets (0'2 mm. diameter) 
being notable. Pyrite with excellent crystal form is abundant, 
and is undoubtedly authigenous, that is, has been produced since 
the deposition of the sandstone. It has suffered no abrasion. Its 



136 POBEIGN GLASS-SANDS. 

presence probably accounts for the 0-02 per cent, of Fe a 3 indi- 
cated in the analysis, an amount larger than the appearance of 
the sand would lead us to expect. 

Sand from the Wedron Silica Company, Ottawa, Illinois. 

This sand is of the same age as the kst, and is stated by the 
Company to be washed twice, thoroughly dried, and screened. It 
is a beautifully white, clean sand, composed of perfectly rounded 
grains (Plate V. fig. 2). The description of the Ottawa Silica 
Oompany's sand applies to this sand also. 

Dr. Harwood's chemical analysis is as follows : 

SiQ, 99-58 per cent. 

Al/) a 0-12 

Pe 3 3 0-02 

CaO' 0-13 

MgO trace 

Loss on ignition O'l 7 

Total 100-02 per cent. 

The mechanical analysis indicates : 

> 0-5 & < 1 nun., 6-1 %; > 0-25 & < Q'5, 88'4 %; > O'l & < 0-25, 5vL %; 
>0-01 & < 0-1, 0-2 %j < 0-01, 0-2 %. Total Band-grade, >0'1 mm., 
99-6 %. 

TOS MS FS _s_ _c_ S "I 
|_6-r 88-4' 5-1' 0-2' 0-2 ; 99'6j 

The heavy detrital minerals, as before, are highly rounded, 
averaging - 12 mm. diameter. The pyrite, which is again abun- 
dant, is clearly not detrital. 

Sand from the Berkshire Glass-Sand Company, Cheshire, 
Mass. 

The sand is produced from a crushed Cambrian quartzite. The 
Company state that it is washed three times and passed through 
a 40-mesh brass wire-screen. An average sample of the sand 
taken from the quarry (and therefore unwashed) by Mr. H. C. 
Demming, who was investigating silica-sands for filtration-plant, 
had a composition as follows : 

Silica 99-28 per cent. 

ATninrnii. 0'49 

Iron oxide 0-34 

Lime 0-12 

Magnesia 0-003 

Phosphorus oxide 0-0047 

Sodinm and Potassium oxides ... 0-38 

Sulphur 0-0096 

Organic matter and loss 0-17 



Total 100-7973 per cent. 



CHESHIRE AND BEBEELEY SPRINGS SANDS. 137 

Dr. Harwood's analysis of the washed sample supplied is : 

Si0 2 99-00 per cent. 

AljO., 0-30 

Fe 2 0, 0-03 

OaO 0-15 

MgO none 

Loss on ignition . . . 0-21 



Total 99-69 per cent. 

A mechanical analysis gave the following information : 

>0-5 mm., none ; >0-25 & <0-5, 76-6 % ; >0-1 & <0'25, 21'3 % j >CH)1 & 
<0-1, 0-3 % ; <0-01, 1-8 %. Total sand-grade, >0'1 mm., 97-9 %. 

T MS FS so S 
[_76-6' 21-3' 0-5' 1-8 ; 97'9' 

The sand is rather fine-grained, sugary to the touch, and fairly 
angular. The detrital mineral assemblage is greater in amount 
(0'04 per cent.) and more interesting than that of the Illinois 
sands. Much limonitic matter occurs, and rnuscovite mica, 
chlorite, green hornblende, tourmaline, and zircon are also present. 

The sand is widely used for the finest cut-glass. 

Sand from the Berkeley Glass-Sand Company, Berkeley 
Springs, W. Va. 

This sand is the well-known high-grade deposit from Berkeley 
Springs, used so largely for table-glass and the best ware. . It is 
produced by crushing the Oriskany sandstone of Silurian age. 
After being crushed, it is sent through a wet screen, then 
steam-dried, and, finally, once more screened. It is kept in concrete 
storage-bins of about 1500 tons capacity, the daily production being 
about 400 tons. 

The chemical analysis indicates (H. F. H. and A. A. E.) : 

SiO, 99-65 per cent. 

Al 2 6 a 0-11 

Pe a O a 0-02 

CaO 0-12 

MgO trace 

* Loss on ignition 0-23 



Total 100-13 per cent. 

The mechanical composition is as follows : 

>0-5 & < 1 mm., 1-5 %; > 0-25 & < 0-5, 97'1 %; > 0-1 & < 0-25, 0-8 % 
>0-01 & < 0-1, 0-2 %; <0-01, 0-4 %. Total sand-grade, >0-1 mm., 
99-4 %. 

PCS MS FS _s_ c 3 "I 
Ll-5' 97-1' 0-8' 0-2' 0-4 ; 99:4 J 

The sand is pure white and consists of somewhat irregular 
grains (Plate V. fig. 1). The detrital mineral percentage is 
small (O'Ol per cent.), and is of the usual type. 



138 TOJiEIGIT GLASS-SANDS. 

Sand from the Jtmiata White Sand Company, Hanover St.* 
Baltimore, Maryland. 

The quany of the Juniata Sand Company is at Mapleton, Pa., 
and is also in the Oriskany sandstone. The rock is crushed, and 
is said to go through five washings and three screenings. 

Dr. Harwood's analysis is as follows : 

SiO 99-33 per cent. 

A1 2 6 3 0-16 

Fe-jO, 0-02 

CaO 0-15 

MgO 0-11 

Loss on ignition . . . 0-20 



Total 99-97 per cent. 

The mechanical analysis yields the following information as to 
grades : 

>1 mm., 1-6 % ; > 0-5 & < 1 mm., 11'2 % ; >0'25 & < 0'5, 85-7 % ; > O'l 
& < 0-25, 0-4 % ; > 0-01 & < 0-1, 0-1 %;< 0-01, 1-0 %. Total sand- 
grade, >0-1 mm., 98-9 %. 

pTCS CS MS FS _B_ jo_ S ~] 
L 1-6 ' 11-2' 85-7' (P4 1 <Fl' 1/0 ' 98-9J 

The sand is subangular, a few spherical grains only being seen. 
The detrital mineral percentage is small (0'02per cent.), consisting 
largely of zircon, tourmaline (blue, green, and brown), ilmenite 
and leucoxene (O2 mm. diameter), rutile, and blue anatase. 

Sand from the Tavern Rock Sand Company, St. Louis. 

This glass-sand is produced by crushing the friable St. Peter's- 
sandstone of Carboniferous age. The Company do not wash any 
sand, but crush, dry, and screen once. The quarries are at Pacific 
Mo. 

Dr. Harwood's analysis is as follows : 

SiO a 99-08 per cent 

A1 2 0, 0-23 

Fe.,0., 0-02 

CaO 0-21 

MgO 0-05 

Loss on ignition ... 0-35 

Total 99-89 per cent 

The composition as given by the Company is : 

99-97 per cent 
0-OS 

i *_*' "ww 

CaO 



Total 100-00 per cent. 



BALTIMOBE, ST. LOUIS (u.SA.) AND COLONIAL SANDS, 139" 

For an unwashed sand, the silica-content is very high and the- 
iron-percentage very low. 

The mechanical analysis is : 

>1 mm., a few oomponnd grains ; >0'5 & <1 mm., 2'7 %; >0'25 & <0'5, 
90-1 % ; >0-1 & <0-25, 6-1 %; ><H)1 & < 0-1, 0'5 %; <0'01, 0'6 %,. 
Total sand-grade, >0'1 mm., 98'9 %. 

KCS OS MS IPS _B o^ _S_-| 
r. ' 2-7' 90-1' 6-1' : 5' 0-6 ; 98'9'J 

The sand is fairly well rounded, but not very clean. The 
percentage of detrital minerals is low (O'Ol per cent.) and the suite 
consists chiefly of zircon, tourmaline, ilmenite, and leucoxene 
(O'o mm. diameter). 



COLONIAL GLASS-SANDS. 

Chemical and Mechanical Analyses of several glass-sands, from 
India and Australia are given in the Tables on pages 154, 157, and 
165. Of these, the Jubbulpore sand is that used in the well-known 
Allahabad Glass-worls, while for the remainder of the samples the 
writer is indebted to the respective Directors of the Geological 
Surveys of India and Victoria. There is little doubt that the 
Colonies can supply their own needs in this direction ; the sands 
examined by the writer have all been of good quality. 



140 LOCATION OF BEITISH GLASS-SANDS. 



CHAPTER XII. 

LOCATION OP BRITISH SUPPLIES OF GLASS-SANDS. 
General Geological Considerations. 

With the view of realizing the geological conditions under which 
glass-sands occur, it is instructive to draw attention to several 
salient facts, in order the better to search for suitable supplies. 
The association of pure white sands with carbonaceous matter has 
frequently been mentioned in this Memoir. Indeed, it may be said 
that every example of the better-class glass-sands in Europe indicates 
that the deposit is associated with vegetable matter. Lippe sand 
occurs with rafts of braunkohle. Hohenbocka sand is associated 
with carbonaceous layers ; Fontainebleau sand with lignites ; and 
Aylesbury and Leighton sands with peaty layers. Some of our 
purest sandstones occur in the Coal Measures, and, of second-rate 
sands, the Heaclon Hill and Bagshot Sands of the Isle of "Wight 
(Alum Bay, WhiteclifE Bay, etc.), Dorset, and elsewhere are inter- 
bedded with lignites ; while the white beds of the Northampton 
Sands (Inferior Oolite) and the Estuarine Series in Yorkshire are 
found in deposits carrying plant-remains. The well-known Brora 
coal in the Jurassic of north-east Scotland is associated with white 
sandstones. The purest Ashdown Sands (Wealden) often carry 
plant-remains. The glacial sands of Lancashire, used for the 
making of window-glass, owe their low percentage of iron to the 
association with peaty material. 

The bleaching of red and yellow sands for a few feet in depth on 
heaths and by the action of peat are other examples of this pheno- 
menon. The explanation appears to lie in the reducing action of the 
vegetable matter. Ferric compounds are reduced to the ferrous 
state, and are often carried off in solution by percolating water. 
Sometimes, however, they remain and are revealed by the return 
of the red colour on burning. 

Estuarine or lagoon conditions favour the formation of white 
sands and sandstones. In our search for glass-sands, particularly 
in the Colonies, we have therefore a valuable indication of the kind 
of strata in which to look (that is, beds containing coal, lignites, 
peaty matter, etc.) and the conditions under which we may expect 
deposition of the required material to have occurred. Simplicity of 
composition and perfection of grading are more likely to be found 
in deposits of late geological age, as exemplified by the occurrence 
of glass-sands in Western Europe. It is very improbable that any 
new and large British supplies of first-class glass-sands will be 
revealed ; but, in addition to the extension of supplies now being 



GENERAL GEOLOGICAL CONSIDERATIONS. 



141 



exploited, deposits .of small extent, at present unknown, probably 
occur in many cases in proximity to, or along the outcrops of, 
strata previously worked. 



Location of 'British Supplies of G-lass-Sands. 

(a) England. Considered stratigraphically (that is, according 
to geological age), the chief localities for English supplies, with 
their corresponding geological horizons, may be detailed as 
follows : 



Recent (blown & shore) Sands. 
Glacial. 

Deposits of Doubtful Age (pre-GHaoial). 



Upper Eocene. 

Lower Eocene. 
Lower Oretaoeous. 



Middle Oolites. 
Lower Oolites. 

Upper Trias. 

Lower Trias. 
Carboniferous. 



Headon Hill Sands. 
Barton Sands. 

Thanet Beds. 
Lower Greenaand. 



Tunbridge Wells Sands. 
Ashdown Sands. 

Kelloway Beds. 

Upper Estuorine Beds. 
Lower Estuarine Beds. 

Keuper Waterstones. 

Lower Bunter Sands. 
Coal Measures. 
Carboniferous Limestone, 



Lower Ordovioian. Arenig. 



Passim. 

Crank, Roinford, etc, (Lanes). 

Parsley Hay (Derbyshire). 
Brassington (Derbyshire). 
Low Moor (Derbyshire). 
Eibden (Staffs). 
Abergele (Denbighshire). 
Ehes y oae (Flintshire), etc. 

Alrnn Bay, I. of Wight, etc. 
Fordingbridge (Hants). 
Longdown, New Forest. 
Charlton (Kent). 
Rochester (Kent). 
Aylesbury (Bucks). 
Aylesford (Kent). 
Blackgang Chine (I. of W.). 
Godstone (Surrey). 
Hollingbonrne & Bearsted 

(Kent). 

Leighton Buzzard (Beds). 
Lynn (Norfolk). 
Oxted (Surrey). 
Eeigate (Surrey). 
Ashurat wood ' (Sussex) . 
Fairlight (Sussex). 
Bulverhyth (Sussex). 
Burythorpe (Yorks). 
South Cave (Yorks). 
Huttons Ambo (Yorks). 
Corby, etc. (Northants). 
Denford (Northants). 
Spital (Cheshire). 
Alderley Edge (Cheshire), 
Workaop (Notts) 
Guiseley (Yorks). 
Mold (Flintshire). 
Minera (Denbighshire). 

Stiperstones (Shropshire). 



Most of these localities and geological horizons are marked upon 
the map, Plate VIII. The outcrop of each formation is shown, in 
order that the direction of the possible extension of glass-sand 
resources may be indicated. Take, for example, the deposit known 
as the Lower Greensand, from which so many of our best glass-sands 



142 LOCATION OF BRITISH GLASS-SANDS. 

.are obtained. The bed is worked for glass-making at Lynn, Leighton 
Buzzard, Aylesbury, and Aylesford; it was formerly worked at 
Keigate, Godstone, Hollingbourne, and in the Isle of Wight. 
Many of these localities are marked upon the map, and will be 
seen to ba distributed over the outcrop of the bed. The area 
marked by the outcrop is therefore that over which extension of 
the supplies may be expected, and which should be explored for the 
purpose. Another important horizon is that of the Inferior Oolite 
(and in Yorkshire, of the Middle Oolites also). The beds are 
frequently variable in this series of deposits, but investigation 
of the outcrop will doubtless reveal extensions or new deposits of 
the glass-sands. 

The Tunbridge Wells Sands and the Ashdown Sands of the 
Wealden area yield important supplies of pure sand-: The resources 
have not been properly explored, and are certainly great. Unfor- 
tunately, the localities where they are at present worked are not 
well situated, for transport. 

The Triassic System rarely yields sands pure enough for glass- 
making, and when such are found the best glass- ware which can 
be made from them is the class of work exemplified by pale bottles. 
The Bunter Sands of Worksop, the Keuper Sandstone of Spital, 
Cheshire, and possibly the similar rock at Alderley Edge, are 
deposits of this character, the first two being fortunately situated 
near to coalfields. 

We may classify these localities broadly according to the kind 
-of glass for which the sand may be used. Obviously the limits 
will not be easy to define, and moreover, as mentioned in the 
Preface, and also on page 151, with the advance of chemical 
research upon glass, the latitude permitted in the composition of 
sands for certain glasses is increasing. 

The shore- and dune-sands occurring around our coasts are never 
sufficiently pure for making other than common bottle-glass. The 
Glacial Sand from Eainford, Crank, and Shirclley Hill in Lancashire 
is used (after washing) for the making of window-glass and for 
bottles. The Eocene sands mentioned from the Hampshire Basin 
have at present been used only for better-class bottle-making, but, 
-especially if they are washed, would be of value for such better 
qualities as lighting-glass, laboratory-ware, etc. The Thanet Sands 
from Kent are utilized for bottle-making only. Highly siliceous 
sands, but less pure and more indurated than those from the Lower 
Greensand occur in the Upper Greensand over a wide area from 
the Isle of Wight to Wiltshire and Kent. Of the Lower Greensand 
deposits, Ayles bury sand can be used for the manufacture of optical 
glass, table-glass, chemical and pharmaceutical apparatus, and 
many other varieties. Leighton and Lynn sands are successfully 
employed for lighting-glass of all descriptions (electric-globes, 
chimneys, etc.), for laboratory- ware, flint-bottles, pressed- ware, etc. 
Aylesford sand at present goes only to bottle-making areas, but 
like the sand from Reigate, could be successfully used for better 
kinds of gkss. The Tunbridge Wells Sands and Ashdown Sands 



UTILIZATION OF PARTTOULAK SANDS. 143 

mentioned as occumng in Sussex, are not at present worked for glass 
purposes, but as their analyses indicate (see pages 5254) they will 
be of service for much good glass-ware, if economic considerations 
permit their exploitation. 

The English Jurassic strata are very variable, and it is possible 
"that sands of great purity not known to us at present may turn up, 
but their thickness and extent must be limited. The Corallian Beds 
often contain claye}' or calcareous sands, and the Portland Sands 
are too grey or brown and impure for glass -making. 

The Kelloway Beds of Burythorpe and South Cave in Yorkshire 
are of great value for the bottle industry of that county, and with 
washing could be utilized for window-glass, lighting-glass, etc. 
The Estuarine Sands from Huttons Ainbo, when washed, are 
suitable for the manufacture of all qualities of glass, even up to 
certain optical varieties. Unwashed, they would serve for bottle- 
making, when the alumina they contain would be of much value 
on account of its strengthening properties. 

The Inferior Oolite " Sands " of the western area (Dorset Coast, 
Bridport, Yeovil, Midford, Wotton, Cotteswolds, Cheltenham, etc.) 
are too ferruginous and are occasionally calcareous. In the North- 
ampton Sands and Estuarine Series, beds of whitish sand occur, but 
are usually calcareous and never very pure. The detrital mineral 
percentage is also high. Sands are said to have been worked for 
glass-making about 1860 from Wansford, Apethorpe, Blatherwyke, 
Burleigh, Gas wick, etc.; but the glass cannot have been of good 
quality. Analyses of sands from Corby, Denford, etc.. will be 
found in the Tables. The Estuarine Sands of the Midlands are 
difficult to work owing to their variability, and are rather fine in 
grain. Their suitability may be determined from their analyses 
(pages 69, 156, and 162). 

The Triassic sands are usually only of value for bottle-making, 
when their alumina-content is a distinct advantage. They are 
not sufficiently well-graded, nor are they very pure. "Washing 
may improve the Spital sand sufficiently to render it pf value for 
better-class glass. 

The Lower Permian Yellow Sands are often incoherent, but are 
too deeply iron -stained and calcareous all along their outcrop to be 
of service. 

The Carboniferous Period was one in which very pure sandstones 
were laid down, the association with much organic matter being 
here noteworthy. The decomposition of pure sandstones (e. gr., in 
Ireland, near Glasgow, in Yorkshire, etc.) has given suitable sands, 
and some very good examples have been found. Such rocks are 
often crushed and washed before being put upon the market. In 
some pale-coloured sandstones the cement is barytes (often derived 
from Permian deposits above), when crushing hardly pays. Nothing 
suitable seems to occur, nor would it be expected, in Devonian 
strata. 

Incoherent glass-sands are not to be expected from Archtean and 
Palaeozoic rocks. Very pure quartzites occur, but the objections 



144 LOCATTO^ OP BBITISH GLASS-SANDS. 

to crushed, rocks (see page 80) and the question of expense almost 
rule them out. Where veiy pure rocks have rotted in situ and 
been exposed to washing by rain, etc., glass-sands may be pro- 
duced. The whitish Cambrian quarbzites of the Midlands are not 
sufficiently pure. Other Cambrian sandstones are less pure still, 
and the same objection applies to Ordovician and Silurian Rocks. 

The high alumina-bearing deposits of Derbyshire and Stafford- 
shire (Parsley Hay, Newhaven, LongclifEe, Eibden, etc.) are of 
very great value for refractory purposes, and so far as glass- 
making goes, may be of importance for resistance-glasses such 
as those required in the making of thermometers, ampoules, 
combustion-tubing, etc., as well as for certain varieties of optical 
gkss. 

(b) Scotland. The Scottish deposits fall into two well-marked 
groups. In the first group, and of little importance, are the dune- 
and shore-sands worked for bottle-making. Those from Jura and 
Islay are pure enough for better quality glass. In the second 
group are the white, grey, or pale brown, soft and decomposed 
sandstones of the Carboniferous System, which have been crushed 
and treated to provide " sands " for refractory purposes and glass- 
making. Such are the deposits belonging to the Millstone Grit, 
Carboniferous Limestone Series, and Calciferous Sandstone Series 
from Caldwell, Glenboig, Hailes, Kolwinning, Kongscavil, Levenseat, 
and Plean. Of these, the best are the Levenseat, Caldwell, and 
Kihvinning materials. The deposits are at present utilized for 
low-grade glass-work only. 

Many of the pre- Cambrian quartzites (e. g. Jura, Islay, Appin, 
Killiecrankie, etc.) seem to be pure enough to crush as sources 
of silica for glass-making and furnace purposes. The expense 
involved in the crushing and subsequent treatment is, however, 
prohibitive. 

It is possible, though unlikely, that the pale-grey sandstone of 
Brora (Middle Oolites) will be worked for glass-purposes, although 
a low-grade fuel is close at hand. 

The glass-sand resources of Scotland (and also of Ireland) are 
thus much more limited than those of England. This is due to a 
geological fact that of the absence or small development of those 
stratigraphical horizons such as the Inferior Oolite, Lower Green - 
sand, Eocene, Miocene, and Oligocene, which carry the best 
glass-sands of "Western Europe. 

(c) Ireland. The Irish supplies, in the same way, fall into two 
well-defined classes. Shore- and dune-sands, usually suitable for 
bottle-glass only, occur at Arda/ra (Co. Donegal), Ballycastle (Co. 
Antrim), Coalisland (Lough Neagh), the shores of the river Foyle, 
Millisle (Co. Down), Portrush (Co. Antrim), Rosslare (Co. Wick- 
low), Saudymount Strand near Dublin, Silver Strand near Wick- 
low), Sutton near Dublin, and other localities. The more valuable 



DISTBIBUT1ON OF THE GLASS-MAKING INDUSTET. 145 

" sands " are obtained from the decomposition or crushing of pre- 
Oambrian rocks from Muckish Mountain (Co. Donegal), Westport 
(actually from Acliill Island), Port-a-cloy (Co. Mayo), Tinanely 
(Co. Wicklow), and other places, and of the sandstones of Carboni- 
ferous age from Ballycastle, Cookstown, and Coolkeeragh. 

The best Irish material is undoubtedly that from Muckish 
Mountain, Co. Donegal. If the rock, which has already been 
described as a partially decomposed quartzite, is *properly treated 
by crushing, screening, washing, and drying, much of it will be of 
service for the best optical glass and table-ware; the material 
generally will be of use for all qualities of glass. 

The old Irish glass-industry, carried on at Ballycastle, Limerick, 
Cork, and Waterford among other places, was dependent upon 
sands from Alum Bay (Isle of Wight), Lynn, and Eeigate. 



Distribution of the Glass-making Industry in the 
British Isles. 

The Maps (Plates IX. & X.) show the localization of the chief 
British glass-making areas *, and also indicate the localities 
where glass-sands are worked, the ports into which foreign sands 
are brought, and the coalfields. It is noteworthy that, with the 
exception of the London district, in which almost everything is 
bought, manufactured, or sold, the glass-making areas are situated 
upon, or veiy close to, the coalfields. The industry consumes a 
large quantity of fuel either directly as coal, or indirectly as 
producer gas, etc., made from it. About a ton and a quarter of 
fuel are consumed for each ton of finished glass produced in tank- 
furnaces, and the consumption is greater in pot-furnaces. To yield 
a ton of finished glass about a ton and a third of raw materials are 
required. Coal, as is well known, is much more bulky and trouble- 
some to move than the same weight of such raw materials as 
sand, hence the location of the manufacture. 

A general statement only is possible regarding the distribution 
of the various kinds of glass-manufacture. 

Optical glass is made in the Birmingham and Derby areas. 
Table and decorative ware is manufactured in the Stourbridge 
area near Birmingham, and in Manchester. London, Glasgow, 
Wan-in gton, and Tutbury also contribute a certain amount. The 
Stourbridge area (including Brierley Hill, Dudley, Walsall, etc.) 
has long been famous for its beautiful "crystal" ware, both on 
account of the quality of the glabs and the artistic character of the 
work. 

Scientific and technical glass is made in Edinburgh and Perth 
as well as the following localities notable for laboratory and 

* The writer was able to make this analysis as a result of visits to most 
of the glass-works in the United Kingdom, and by using freely the excellent 
card-catalogue of British Glass-Manufacturers, compiled by the Board of 
Trade. 



146 LOCATION OP BHITISH GLASS-SANDS, 

medical apparatus: London, Leeds, Birmingham, Bamsley, Man- 
chester, Dudley, and St. Helens. Gauge-glasses have been manu- 
factured at St. Helens, Manchester, Birmingham, and Perth. 

The manufacture of electric bulbs, etc. is now being earned on 
near and far, but possibly the following may be considered the 
chief areas : Stourbridge, Birmingham, Tutbury, Knottingley, 
Barnsley, Leeds, London, and Tyneside. 

For lighting-glass generally, the districts including London, 
Manchester, Glasgow, Stourbridge, and Birmingham are note- 
worthy, but the industry is carried on in many other towns. 

For pressed-ware, Glasgow, Gateshead, Manchester, Warrington, 
and Sunderland should be mentioned. Ship- and lamp-lenses are 
made in the same areas. 

The plate-glass industry is practically confined to the St. Helens 
and Birmingham areas. Sheet-glass (window-glass, stained glass, 
etc.), is made at St. Helens, Birmingham, and Oldbury, and staining 
is earned on at Edinburgh. 

In the matter of the total amount of raw materials used and fuel 
consumed, the bottle-making branch of the industry is of course by 
far the most important. It would be laborious to enumerate the 
places at which bottles are made ; the manufacture is ubiquitous, and 
only the chief localities can be mentioned. The South Yorkshire 
area is, of course, the district par excellence for this work. The 
bottle-industry of Tyneside has declined considerably. Medical 
bottles are made in the London, Yorkshire, Gateshead, Manchester, 
and St. Helens ^areas. Flint-glass bottles are produced in the same 
districts, and for ordinary pale and dark bottles the following 
localities also must be added : the districts of Sunderland, Edin- 
burgh, and the Firth of Forth, Bristol, Newport (Mon.), Queen- 
borough, Dublin, and Belfast. 

Finally, as we should expect in a city winch manufactures 
everything from a pin to a steam, engine, " egg-boilers " and time- 
glasses, as well as the largest and most beautiful glass objects, 
have their birth in Birmingham. 

From what has been stated above concerning the kinds of glass 
for which various British sands tire suitable, and the location of 
both these sands and the corresponding glass-making areas, an 
idea may be obtained of the transport required. To assist the 
reader, the most important canals and navigable river-systems have 
ben inserted on the Maps (Plates IX. & X.) together with tho 
chief railway connexions. Transport by cnnal, sea, or rail, and 
the very variable freightage iiites on diffeiimt railways will, however, 
prevent comparison of the cost of moving any individual supply into 
any particular manufacturing area. Nevertheless, the maps aro 
given for what they are worth. 



ECONOMIC CONSIDERATIONS. 147 



CHAPTEK XIII. 

ECONOMIC CONSIDEKATIONS. G-ENEEAL 

i 

In the development of the national resources of iu\v materials for 
glass-making, questions of the cost of working, suitable treatment, 
and transport play a most important part. 

The margin of profit upon sands is small. This and the fact 
that our large export coal-trade to the Continent enabled foreign 
sands to be brought back very cheaply as ballast have been mainly 
responsible for the small development of home resources of sands 
and allied rocks, and for the lack of investigation into them. The 
glass-manufacturer hitherto has not experimented to any great 
extent with British sands, and is thus not generally acquainted 
with their potentialities. Moreover, before 1914 it was by no 
means certain that the best British sands actually reached the 
manufacturer. Owing to lack of systematic working, want of 
proper treatment and careful transport, British materials sent to 
the glass-making areas have to overcome the prejudice which they 
previously caused. This state of affairs is now rapidly being 
remedied, since the cutting off of a considerable proportion of foreign 
supplies of sand, due to the shortage of labour and shipping caused 
by the war, has necessitated the systematic surveying and exploita- 
tion of British mineral resources. 

"When brought as ballast or packing for bottles, Belgian and 
Dutch sands could formerly be delivered in our East Coast estuaries 
at from 4s. to 5s. per ton. Fontainebleau sand was similarly 
delivered (although it was not usually brought as ballast) at 10s. 
per ton. These prices were doubled or trebled by the time the sand 
reached inland glass-making districts, the railway freights on sands 
being high. Even then the prices were below those of British sands, 
since the cost of production of the latter was, as a rule, greater. 

The prices at which sands etc. can be supplied are, of course, liable 
to fluctuation according to the state of the labour market, cost of 
fuel, etc. The figures quoted in the foregoing chapters therefore 
vary within small limits. 

Since the outbreak of war, partly owing to the greater demand 
for British materials and partly as a result of certain facilities 
having been granted which permit cheaper working, British 
sands are being delivered at a price which will enable them to 
compete successfully with foreign supplies. This improvement has 
been effected and a systematic development made possible by the 
high cost of foreign sands at the time of writing. Fontainebleau 



148 ECONOMIC CCXN'SIDEBATIOB'B. 

sand costs from 20s. to 60s. per ton, and Belgian and Dutch 
sands 17s. to 28s. per ton, when procurable at all, according to the 
position of the glass-making area. Even when prices return to 
the normal level it will be possible for sand-merchants to exploit 
their deposits if the demand is sufficient and if railway and canal 
facilities are given. Some British sands have for many years been 
carried as balkst from one part of the coast to another. 

High class glass-sands, like the sand from Fontainebleau, have 
frequently been used in this country in what might be termed 
a wasteful manner for common glass-manufacture. In certain 
maritime areas the sand can be obtained as cheaply as a less pure 
one, and is therefore used. In other areas, rather than have 
two different sands in use in the same glass-house, entailing 
possibih'ty of confusion (which is perhaps unnecessarily feared), 
the manufacturer uses the same sand for crystal table-ware and 
also for commoner glass. 

As a result of the importation of foreign sands, many British 
supplies which were formerly worked have been abandoned. Giass- 
sand appears to have fallen very considerably in price during the 
last fifty years, for, in 1858, Aylesbury sand fetched 26s. per 
ton at Aylesbury. In comparison with the present prices of 
British glass-sands given in the previous chapter, it may be 
stated that the average price in the United States of America 
is 4s. per ton. 

Each of the economic factors will be considered in turn. 

Workability. In recommending sources of sand suitable for 
glass-making (or, for that matter, any other industry) due con- 
sideration must be given to the very important question of work- 
ability. Since the margin of profit on sands and gravels is low, 
attention must be paid to many factors other than those concerned 
with the actual properties of the sand. Of the latter, the high 
silica and low iron-content, low heavy-mineral percentage, absence 
of harmful minerals, the even grade (medium or fine sand), and 
possibly the shape, are the chief points to be considered. High 
content of alumina and potash are at times valuable. 

In the field occurrence of the sand, due regard must be paid to 
the regularity of the deposit, the quantity available, the location 
with respect to supplies of fuel and markets, and to transporting 
routes, whether by road, rail, canal, or sea. The accessibility of the 
deposits on hills, near bogs and marshes, on river-bottoms (from 
which they are dredged), or in sea-cliffs as well as the conditions 
of quarrying (workable depth below ground-level, position of water- 
table, direction of drainage, thickness of overburden, etc.), and the 
state of the local labour market have to be considered. 

Treatment. The cost of washing sands is usually about 6d., or 
perhaps rather more, jper ton. The additional handling and moving 
consequent upon washing, drying, or treating magnetically a sand or 



149 

crushed rock, raise the cost considerably. Little washing is done 
in England, and where it is carried on, ordinary draining and air- 
drying are generally considered sufficient. The question is, of 
course, one of cost ; hut washed deposits ought to be dried before 
being put on rail or on board ship, for carriage should not be paid 
upon water. Sands have the power of retaining a considerable 
quantity of water, and their hygroscopic nature should be clearly 
recognized. When crushing, washing, and drying are earned on, 
the proximity and price of fuel supplies and the available water- 
supply are important factors. If the crushing, screening, etc., of 
pure sandstones and quartzites ever becomes a paying proposition 
in this country, a considerable quantity of raw materials will be 
found to occur in the older rocks, especially in Scotland and Ireland. 
At present, for all but the best glass-ware, most of these are 
ruled out. If a rock which has to be crushed is to be worked 
successfully, it must be exceedingly good in chemical composition, 
and fairly accessible. 

Such rocks are at times of value for the alumina or the alumina 
and potash, as well as the silica, which they contain. If they are 
very hard, subsequent electromagnetic treatment is necessary, after 
crushing, to free the sand from particles of steel, etc., derived from 
the crushers. The cost of electromagnetic separation is Qd. or 
more per ton, according to local conditions. 

Where sandstones and quartzites are disintegrating under atmo- 
spheric conditions, working may be carried out profitably, for the 
crushing, washing, and drying are done by natural meins for 
the exploiter, and the deposit often needs screening only. If such 
deposits or other glass-sands are situated at a suitable elevation 
and water-power is available, the use of monitors to wash down 
the sand may be found advantageous. Gravity will then assist 
in transport, and the washing may well improve the quality of 
the product, both as regards mechanical composition and iron- 
content. 

The enormous glass-industry of the Middle Mississippi Basin is 
supplied by crushing the St. Peter's Sandstone, which crops out in 
the States of Minnesota, Wisconsin, Iowa, Illinois, Missouri, 
Arkansas, etc. It is blasted, crushed, screened, washed, and dried. 
The well-known Oriskany sandstone of West Virginia (Berkeley 
Springs, etc.) is similarly treated (see Chapter XI.). Certain pure 
quartzites are, it is said, now being crushed and treated in Sweden 
to provide the sand for the manufacture of the well-known 
laboratory glass. Before 1914, Fontainebleau and Lippe sands were 
imported for the purpose. 

Transport. Carriage by road is expensive, and aerial transit, 
even for short distances and when aided by gravity, does not 
always appear to be satisfactory, besides being frequently costly. 
Railway freights upon sand (as well as upon the finished article, 
glass) should be reduced so as to permit the transportation of 
English glass-sand over any distance. Glass-sands, being purer, 



150 ECOITOMIO 

are unfortunately at present subject to a more expensive rate than 
ordinary sands. Canal -transport should replace rail -transport 
wherever possible in developing British sand-resources, and must 
be further revived and reorganized for this purpose, as too few of 
our deposits are situated near the sea or large rivers (see Plate IX.). 
There is urgent need for the improvement, repairing, and widening 
of canals. With a decrease in the cost of transport, it may well 
be that the sand-merchant will find it possible to treat and 
improve his sand (perhaps to dry as well as wash and screen it) 
before delivery, and thus more successfully compete with foreign 
supplies. Co-operation between users and producers ought to lead 
to increased demand, and therefore to more extensive and cheaper 
exploitation. 

. The levying of greater import duties upon foreign sands may not 
be desirable, but it may have to be considered. If British sands are 
to be exploited to any large extent, the question of the necessity 
for a revision of freights, leading to standardization and reduction 
is urgent. It should be noted that certain Continental supplies 
of glass-sand are larger, more regular and persistent, and in part 
purer than deposits in our own country, 

Statistics. The available figures relating to the imports and 
exports of sands are of the most meagre character. In the Home 
Office Returns of Minerals, etc. *, it is stated that the Production 
of Gravel and Sand in 1913 was 2,409,152 tons of value 184,818, 
and in 1914 was 2,498,872 tons of value 215,351. The value 
was therefore about 1*. 6d. to Is. 8d. per ton. The production of 
sandstone in 1913 was 3,977,303 tons of value 1,143,431, and 
in 1914 was 3,464,528 tons of value 1,057,096. The value was 
therefore about 5s. 9d. to 6. per ton. In 1915 the output of sand 
and gravel was 2,350,267 tons of value 213,373 (Is. lOd. per ton), 
and of sandstone, 2,520,856 tons of value 758,325 (6s. per ton). 
No separate figures exist to indicate even what proportion of the 
total was occupied by sand, much less to show what was the 
separate production of building-sands, glass-sands, moulding-sands, 
soap-making sands, filtration-sands, abrasive-sands, etc. 

For the following figures dealing with imports and exports of 
sands, the writer is indebted to the Comptroller- Q-eneral of the 
Department of Commercial Intelligence of the Board of Trade. The 
total value of the exports of Earth and Sand of British production 
during the five years 1911 to 1915 was as follows : 

1911 .38,884 

1912 23,912 

1913 23,470 

1914 15,773 

1915.... 10,655 



* Home Office : Mines & Quarries General Eeport : Part 1H., Output for 
1915 (1917), -and previous issues. 



GKENEBAL BEMABKS. 



151 



STATEMENT showing the Imports and Ke-exports of SAND into 
and from the United Kingdom in the years 1911-1916. 







Total 
Imports. 


of which 
Belgium. 


from: 
France. 


Total 
Be-exports. 


1911 


Tons 


Tons 



223,095 
85,322 

228,822 
89,338 


197,670 
68,623 

197,187 
68,712 


25,554 
15,377 

27,582 
18,399 


7 
15 

8 
27 


1912 




1913 


Tons 



273,352 
103,095 


233,754 
79,085 


35,157 
20,724 


1 
2 


1914 


Tons 



195,860 
80,643 


150,945 
54,165 


33,523 
19,173 




1915 


Tons 




102,103 
65,433 


35,043 
20,239 


33,662 

24,815 


537 

741 



With the exception of a little special moulding-sand and fumace- 
sand, this imported material may be taken to be sand for glass- 
making purposes. The figures tell their own story of war-conditions. 

General Remarks. As a result of the chemical investigation 
which has been going forward while this geological enquiry has 
been in hand, it has been found that a lower standard of purity 
than that hitherto admitted may be permissible in glass-sands. 
Owing to the paucity of chemists and works' laboratories in the 
glass-trade generally, little check has been kept upon other raw 
materials, and these have frequently been found to be impure. It 
should be possible to obtain the latter in a high degree of purity, 
and if any latitude is permitted, it should certainly be in the sand, 
where freedom from iron and casual impurities is more difficult to 
ensure than in manufactured chemical products. The sand has 
often been suspected, while the manganese dioxide, red lead, lime- 
stone, or even felspar, have been responsible for the^ iron. On the 
other hand, by varying the composition of the glass, less pure sands 
may be used to produce excellent ware, of water- whiteness and great 
brilliancy. The limit of iron oxide in sands for certain optical 
glasses may, according to Professor Sir Herbert Jackson, even 
reach 0'04 per cent. 

The cost of chemical treatment of sand may also not be 
prohibitive when the manufacture of optical glass is under con- 
sideration. 

While there are deposits in this country equal in quality to 
Eontainebleau sand, they do not appear to equal that deposit 
in ' extent and maintenance of sample. Our very pure and well- 
graded sands are of limited extent, bxit we possess large supplies of 
sand suitable for flint-glasses, soda-glasses, laboratory- ware, lamp- 
chimneys, globes, bottles, etc. Suitable sands for black and green 
bottle-work are common enough, and are widely distributed. The 



152 .ECONOMIC) CONSIDB!RA.TIO]!fB. 

price paid for sands for common glass in many British areas is far 
nigher than it need be. 

Q-ood crystal -ware has been made from Aylesbury sand, and 
the application of this and other sands to best glass-work is steadily 
growing. Selected samples might well be tried for certain optical 
glasses *. For such glass the variation in cost of sand is small 
compared witb the considerable cost of production. It has been 
said that the whole world's trade in optical glass would not yield a 
stockbroker's profit. Before the war the production of optical 
glass probably did not amount to more than a. few tons a year. 
The price of the sand is therefore not such an acute question, 
and a highly desirable sand will be obtained at any reasonable price, 
even where transport is expensive. 

Early in this Memoir it was pointed out that sands suitable for 
glass-making (and therefore carrying a high percentage of silica, 
or silica and alumina) were of great value to the steel-founder 
for furnace-bottoms, soaking-pits, moulding- sands, silica-bricks, 
crucible-making, etc. We must note that the price paid for 
such sands by steel manufacturers and founders is usually well in 
advance of, and sometimes double as much as, that which the gla.ss- 
maker is prepared to pay. Freedom from iron oxide or a very low 
percentage of it is not essential to the steel-maker ; it is therefore 
desirable that the best silica-sands should, if possible, be retained 
for glass-making. Many deposits exist which are of great use as 
refi'actories, but are quite unsuitable for glass-making. 

Glass-manuf acturers have been very fortunate in being able to 
obtain from abroad large and constant supplies of their essential 
raw material, pure sand, at a comparatively low price. The con- 
stancy in grade and chemical composition has enabled them to go 
forward with very little alteration of batch, and with no apparent 
need for investigation and analysis. The future cannot be ignored. 
It must be understood that foreign deposits, in particular those 
of Fontainebleau, are not inexhaustible, nor is it likely that they 
will always arrive in this country so cheaply or so true to sample 
in consignment after consignment as they did before 1914. The 
output of Fontainebleau sand might at any time be restricted for 
domestic reasons, or a tariff might be put upon it. It therefore 
behoves glass-manufacturers to investigate the properties of their-, 
glass-sands and the questions of suitability or unsuitability of 
British supplies. More skilled chemists must be employed .in the 
works to investigate not only the finished products and the neces- 
sary mixtures for special glasses, but also the chemical and 
mechanical composition of their raw materials, including sand. 
The discussion of the uses and nature of sands, and of the methods 

* While this Memoir has been, in the press, excellent optical glass has 
actually been manufactured from a number of British sands, many less pure 
than Ayleabury Baud. 



CONCLUDING fiEMAEKS, 168 

of study, together with the requirements of good glass-sands, have 
been expanded in this Memoir with the view of aiding glass-manu- 
facturers to investigate sands for themselves. Chemical analysis 
is familiar to all. Mechanical analysis can he carried out with 
very little apparatus, which is also such as can generally be blown 
in the works. Mineral analysis indicates the presence or absence 
of certain objectionable minerals in glass-making, and will enable 
the manufacturer to determine, within certain limits, whether his 
successive consignments come from the same bed or quarry. The 
last method of work, for example, is sufficient to prove at the 
present time whether the consignments of sand, which may well 
vary slightly in chemical or mechanical constitution, are the same 
Belgian or Dutch sand as that hitherto obtained. 

Our Colonial resources of sand, particularly with reference to 
moulding (or, perhaps, refractories generally) and glass-making, 
ought to be thoroughly investigated. If it becomes desirable that, 
for certain special glasses, such as the valuable and important 
optical glass, the Empire should become self-supporting, it is 
highly probable that sands of sufficient purity and of suitable grade 
will be found in the Colonies, and may be shipped home, possibly 
as ballast. Such sands occur, among other places, in India, British 
Guiana, South Africa, and Victoria. The pulps obtained by crushing 
quartz-rock for extracting gold are often very pure ; they accu- 
mulate in large quantities, but the remoteness of their location 
possibly rules them out. A ' revival of interest has recently 
taken place in Indian glass-making. The Tertiary deposits of 
Northern India are of similar age and character to those of 
Western Europe, which contain such excellent glass-sands. India 
may, therefore, well be self -supporting in the matter of glass-ware, 
and, if desired, may provide the necessary pure sands for British 
pptical glass-making. This is one case among many, but it serves to 
emphasize the desirability of further investigation and of closer union 
in industrial and scientific questions between the Colonies and the 
Mother country. 



M. 



154 



STATISTICS. 



TABLE I. BKITISH Q-L ASS-SANDS : IBON- CONTENT. 

"With a few exceptions, complete analyses -were not made of the sands 
mentioned below. 

Percentage weights, as Fe a O s . 



Page 






Page 






81 


Pre-Gambrian : 
MTirik]R'h MoTiTitflrin, Trench 1 .. 


028 


90 


Jurassic : 
Brora 


12 


: 81 
81 


2.. 
3- 


022 
009 


65 

65 


Huttons Ambo, unwashed 
washed 


13 
03 


81 
96 


Bulk sample 
Westporfc, unoruHhed 


02 
004 




Weald&n 




96 


crushed, No. 3 


04 




"RnTliin 


Ofl 


93 


Port-a-cloy (a) 


1-82 


52 


Pairlight, old pit 


02 


93 


(6) 


09 


52 


"htiroh pit (hnlk) 


02 


93 


(c) 


23 


52 


,1 9 , another 


023 




Carboniferous : 




52 

54 


selected.. 
Btdverhyth 


002 
04 


86 


Caldwell, washed and screened . 


08 


55 


AshurHtwood (a) 


01 


91 


Idookstown, red sand 


04 


55 


(b) 


015 


91 


washed 


02 








92 


Goolk'OWB'gli j TiTvwftBJ 1 I'd , - . 


13 




Lower Qreensand 




92 




075 


58 


Leighton Buzzard, unwashed 


14 


89 


Glenboig, N.B 


27 


58 


washed , ... 


09 


82 


(^niRftley, TinoTTi^herl 


03 


56 


Tiynn (Boara), imwashed 


19 


82 




09 


56 


,, ,, double washed 


04 




Londonderry 


11 


56 


(Gay & Wilson) 


16 


115 


Meldon rook, A ^ 


Fe a 8 
03, 




Eocene : 








PeO ; 


71 


PoTfJingbTldg^, A , 


03 




[ 


26 | 


71 


B 


02 


115 


Tt -f 


FeO ! 


69 


Longdown, unwashed 


09 






15 ! 


69 




06 


83 


Mold, unwashed ' . . 


024 








83 




020' 








115 


Par china-stone, uncruahed 


08 


102 


Doubtful age : 
Edbden 


38 




9> ornahed 

Permian : 
Pontefraot, treated 


09 




Glacial : 


71 










washed 


68 




Trias: 




64 


Tfraipfnrd, irnw-nlied , . . . ...,.,,.,. 


05 


76 


.Alderley TMge ., , 


12 


64 


,, washed 


03 


127 


TJagleRoliffe, irntrefttfld , . . . 


20 








127 
127 


treated (coarse) . . . 
(fine) 


03 \ 
048 | 


77 


8hor0-8aiids : 
^TdaTft, Mftghflrft 


70 


84 


Spitftl, unwashed , ,. . 


06 




fflnTin.lri1ty , , , , , 


1-23 


84 
74 


washed (another sample) 
Worksop, unwashed 


09 i 
51 i 


139 


India, 21/186 


08 


74 


,', washed (anaLJ.H.D.) 


19 ' 


139 


Z/624 


24 















These sands are also of value for refractory purposes. 



155 



aj 

I 



I J 




. . _ J CO <M tO (M * 

ooooor-ioocsicp o o o 
-^-------.Ai o oo 



d o o d d d p' d d o d o p 



do p B 66 do 



N r-l 
O -^ 



<-IOOOi-IOO(MO 



ta if 

cb co 




Pre-Ca 
Appi 
Holy 
TTip.Ti 
M 



rS 



ed, 
B 



.B 



, 
N 



111 S H = s" ^ 

OOP H E i2 i2 

ooci3 MM a a 

(0? too :03t04 e^a tO^ 



OiOiOOCOCOCOCOOO OO 



M2 



d 6 J 6 66 d d 



0666 66 ooo 



Q r rQ r^ r^ T3 . w . w - w - v w - g 

riodd dd dddddddddfldd^a 



oOOi-lOOi-lO 



ssss s s 



ill 4 itlll . .li||I . 




157 



(N <N 

gs in 
cs o 

as o 



CO OS CO <N CO 



'"Nri o'T'S 

2 cil -'S o eo "? 

< ?o o -5 oo 



a 

00 OS 5 OS O O i-H 

i> a. g o> ,-! o 
ds as -p ^ O ra o 

01 os . J3 a <g o 



+ r I * 
ooSP 

-ii riO 



00 CO 10 
CO CO CO 

o o o 



d a 



<D O 

i i 






fl a 



rH CD 
rH oa 






ogooo 



OOOOO 



-g 



IM CS 

O O 

6 6 



-^ co N 10 

O iH O O 

0006 



o o => ri s fl o 



ONiHOtoOOiH 



o -* 
6 eb 



ri d 



OS rH 
rH CO 



OS O CO -^ CO 




S 

eg - 



o cq -<ji * vp 

iH O O 00 

o o o o o 



Cb 



i-H O 



O O U7) CO O O^ 
t^ CQ Qd ifD tH CO 

I s - 00 i>- 00 <3i 



cis 



lf>8 



o 

w* 

I 




S -d 






O 1 




o 



159 



S- 9 r 1 



ss, 

o<=Si 



Q 5^8 I 3 




1J9 O iH CJJ ^H O N 00 CO CS Op o3 
OCvIi lOOOOOlN ^ OilO 



3 o 






oo co oo oo 



160 



co o t~-* 

CO OS CO OS 

o t- eb 6s 
^i I-H cq i-i 



00 O rH 

jft N O 
do cb -^ 

rH i-H Oq 



co co 

rHl> 

cb eo 
cq cq 



OSprHO-^OSCpOSrHOS Cq 
CO CO CO CO J> US -* Tfl CO rH US 



03 

PH 

v_/ 
M 

W 
o 

o 
% 



I> rH 'f OS 

ep to cp 1-1 

OS OS O O 




^. mmosoieoos osmco 

9> ?> N co cp os o os o os 

" - .6666696 6s 6 os 

elO O O O O OS O OS O OS 

QrHrHrHrHrH i-H rH 




in eq * eq 

OrHOOOO 'OOO 



CO OJ 

05 (M 

6 6 



CO rH Ot US 
J>- rH J>- CO 

-^ cq oq eq 



ifti-icqoi>incooscoos 



eq eo mr- 
rH 'f ep o 
cb cq eq cO' 



666 



os os -^ IH o cp rH eq eo in * 
6us66cb6st-i?-6oq cb 



oo co r* co 

rH rH O O 

6666 



CO ift CO 
O rH O 

666 



O 00 O O rH O : ri O lH 

666666 660 



COrH 

rHO 
66 



OHCOCq .COCO 

ooo : eqo 
666 'oo 



o CD us en 
eq oq cp rn 
At 6 6 6 



co us t- I-H o eq 
o o o eq o eq 

666 6 rS 6 



r^iftcoiftcoeo .OOios 
eqpOOprH ;0qoqcp 

666 



eq co 

o o 
6 6 



* rH CO CD 
CD ^1 CO 10 
O OS OS OS 



* co ^? 

OS CO CO 
ift ift eb 
rH rH rH 



1ft CO 

O Oi 

6s do 



co i> oo i> -* co moos 

OS-^rHpl^-OD .J>-lpp 

: co 6 do 
r- c- t- 




161 



a 




V 



^ 

. 6 o 
A V 



V 



OrH 

AV 






rH e_q co in .cq cq eq os M op <p eq 
00 -* cb o ob cs cb A os i>- co -^ 

OS OS OS OS OS OS OS 00 OSOSOOOS 



COOinOinor-CDOOninOST-ICOin 



OS OS "* l-l 



op i>- <? us ep ep co os !> co op * 

O-JpeOcbrHOrH lh r-l OS -ih no 



i r-i co o in cq cq eq cq os cq * a 
i rH o eb <b o 6 oo ooojiH 5, 



gsgsopinepcpinosincpirtopt-O'* cp co cq us eo r-i o in oqincsioo-g 
~ ~' '--'-'-'- ' ' ' ' ' ' i Ai cb cq o o r-i in 53 

^ ^^ I 



i m I-H 



coosrH-^it* .KOOinoscpr-cqeo oooseposcpcpin cq iMrH<pcp 
cq co co in cb : r~cq osiheqihos-^irH CNicsioihcvi'^cb o cboooo 
t-t-*-co P oo-*in-*eoco oo oo oo t- oo in co cq inrinoo 



i r- cp cp co . . . eq ep os ep 
i -^i os cb o : : : <b rn * cq 



cpuai>i-icpc>^- rn cpcqirtcp 
ebinoiJ>rHoeb o iHOsebr- 



A 



e 
o 



-^Q 
i> : co -P 



(M rH 

AA 



;:;;;;;;;;;;; i 


: : 1 1 '. '. '. 




i....iN!!!M!l ! 

|" Hi : : : : : 






i S ^^^"s o 

5 -p 11^ 

d "3 g 


: \ -. :m 
R IJig^-S 

tfirtMhi H 


^ 





C 
JjC 
C 
G 





ill 



COCOCOCOCOCOCOCQCOCO 



162 







Kb w t*. . 5 S . 9 . 

* - g . & I s i g B g a g a J a 

ll I "fr-i-S ^1 tils' 1& ll 

r "ft &ftS S'a 'Qja'uaj rafi) d n 




! 
& 





i ss 



i 



1 



ffi 

I 

r- 



-3 

ii 

: el - fe-3a" 

,K,S d "63'Sm 
60 c3 & JQ Pi P oj 




O3 01 01 03 04 OS Od Oft 



CS 00 W OT SO t- W US W *D r-i N OS O 
Oi OD eb as QDco(6itbbdbai 



rt -Jl l/S O 
O O O iH 



OOOOOTNOO 



1H -* 00 00 

o o o w 



oq p cq cq 

O iH N O 



O O 



iH ?O M l/S 
> (jq * ih 
1-1 }< 



pos 
< o da * 



oq ob - o <i -* 



i>- oa i>- 

M >rt * CS 
00 US * 00 



eg TH op op 

eboihoaojTpcqcbeb 0j r- oihob-* ihoiHeo-^cioloTH obebdb 



ft 



: r-t oq : 


:tH<ra.f 


3 .9 :t-o eo < I*--*? ; 


; irtti^c^r^-cooq Tti 


' rH O 


' 9 

V 


3g-66o USOTHW- 
1 & eq n eq 


o ' ' eq -* oq cq TH . - . 

iH 




| 


t fc 






j 


D 03 ^A > 

l *H 








^ 








<b3 








<?> a cT 1 ?^ 

:::::. * a a to to : 


M . . . . 

: :::::: 6 : : : : 



A r ^ 

AA 



3 =f 




s, _ c3 ta hH 

I.lllii I 





164 






I 



gj g 



- S 



rilf 

H 



A 



H fe 



eq op 
oo o> 



ajosooroooi> t- 



I> >JS O 
OS - US 



OrH oocar-^woso oo 

rH rH rH O rH O O O -^ 



- : BS ss ^2- 
ll 1 1 " 



10 ob co as t~ 03 



A^ 



oorH oepcpo<prH J>- 




W - 



m 
g 



0^6 
A V 



w f 3 

Ivli 



> 

00 S t- rH 00 OS t- O 



OO CO Cv] 
(N CM 



t-CJi oeoosgsifscpt- cp 

rH 00 i-H t> 00 rH 



^-iooicaoao3pcp 
oawoNoo^o 



A 



AA 




. 






f! P 




t- to so f- t- 



165 



a 



H 

<D rjfl | 



fp 
lll 



SI 



" 8 - ft rt 

& e . 1 



p 01 
c3o do 

05 OS 



us w GO o o w 
i> 01 as cs 6i 6s 



01 ra oo CT> 



O OS I> OD 



O rH O O 



tp VI 

o 6 



osMOdiceo ip ( ? 11 P'? l 9l 3 '? 1 ? l r Hl r i y i P < ?'9 ) ^? 1 * ;l "? ^'J'T 1 

Qq <~^ o O O O O ^^ O O O ^? i^t i~l O O O O OO ^^ O O O i~l ^? O 




qo rHr-t- 
do r-ioaw 

1> J> 00 Ci OJ OS (N I 5O I> CJ i-l O5 00 W OS 00 




t I>t r- 'r-t~I>- ;I>r~ ;t- ;t ; ; ; ; ; ;J>t~I> 
r ^ft>i> ; '. Ic-r r^ .c^c^ .i> !* i> t* - 



166 




I 

fc 

d 

PH 



I 







rf.S 



oo o eo 

rH oq rH 
000 



6 6 



i 



H 

M 
O 




167 



-!) 

OQ 



I 



a 

PH 
O 

g 

a 

PH 

O 



H 

3 
J3 

hH 

i 

w 

I 




168 



49 

rt 



H , 



I 



P 
^ 
H 



4 

f 

IT 

s 

I 

PM 



o o o o o o o 



IX) lH OS W 

^ 6 co J> 

OS OS OS OS 



O r-l 

6 6 



o 
V 



o o 
AV 



O 00 CO Oi 
<N 






t P. 



V 



i :S> 



N 

6 6 
V V 



rfi rfi CO I^ 



O OS V> CO 00 r-l 

os : os IH cb t- in 6 

i I ^" CO 



, 3 



O> 7< r-l d M "ft 

6 IH Ai a A< 6 



A 



, EH 

! f 

, ! 
M 



jerg 
aek.. 



le Fjord, H 



1 if -a 

S fi P 



m to o .3 

'S 1 '5* tc> ?d 

. H " i* -P 

r* O C3 \> ffi 



? 
bo 



JT CQ 

1 ^ 



48 



ja 's- . 
v J ra 

I Sli 

J-i O 'O 

a <g 

IB 
R^ 
* & 



170 



02 



Ct5 

fe 

I 



O 

S 

Q 
1 

d 



3 

EH 



I I 
W I 1 

f& 



;! 


1 * 

on & 
^" 8 * "* 
ta 








S 







| 




.3i s *a 


O tO ^) O5 'C^3 


en 


M llAS 


o> o> o co J> 

O OS Oi Cft Cft 


CO 

.09 


s 


r^ on "^ o co 


CO 


o o a 


O O O iH rH 





V H 






. 96a 


CO OQ CQ rH CO 


10 


V 1 


O 


o 


38 


CO rH CO ^ CO 


I-l 


QCJ ^ G fj 


r-l "3 O O TH 


to 


AV S 


ea 




rf Sd 


I-l -^1 H I> tO 


iH 


* A^ 


to co t* 10 CD 
t^ co OS co J> 


o 

A 


ft -i _s 
mi. \/ H 


CO T-H 1ft N 


^ 




iH CO i-l r-l : 




A-e 


CQ i-l 




00 r-l Q 


to 




A | 


I-l 






: M 






I" 






d | 


ID 




*. B . * 1 


jj 




S fc * 3 


3? 








id 







g 


r ^ ^ e> 


q-j 


. 


6 & | ' S S 


1 




5? 3 "3 'd g 


j^ 






2 




ig H3 QJ 


R 




| j> -a -1 g. 


i 




1 & 1 1 


H 


1 " 


CO CO CO CO CO 


CO 


OH 







II 7 9 



^ ' 

F,- ^' * 



SKIT. Xtiss 



J?L. I. 




' n 



c 
o 
i " 

rt o 

o .H 

ip rt 

11 

E LU, 



=5 o 

3 -c 

4J O 

WOT 

oi 

bb 
iZ 



tt-J 



f "' 



1U 



O 

e 

o 



ho 

iZ 




BRIT. RES, 



Pz. II. 




: ig. 1. Quartz (faint and^clear) and fel- 
spar (turbid) In a good glas8 T 8and. 



X40. 

ig. 2.--Heavy mineral residue from a 
British glass-sand: kyanite, stauro- 
lite, tourmaline, ilmenite,/etc. 



Epidote and a crystal 
of Tourmaline (dart). 



Fig. 3. Zircon and Rutile: harmful 
minerals in glass-sands. 



Photomicrographs of M{ 



Kyanite. 



40. 




Staurolite. 
lS;.4v- Heavy minerals from Sands. 

itted light). 




RES. Q-LASS-SANDS, PL. Ill 



Ftg. 1. Fontafnebleau Sand. 



FFg 2 LippeSand. 



f fr 
..J 




>, 

cc 



Ffg. 3. -Aylesbury Sand. 



&*?('* --'"' ; i /^' 

"^' ; S "'' V, .:'-.''.' 



Fig. 4. Godstone Sand, 



' -" i V -. -' 
. i . -^ .if. 1 1 ,., 

" '' 



Fig. 5. Burythorpe Sand. 




Fig. 6. Crushed pock : Guiseley. 



Photomicrographs of Glass-Sands (reflected light). 

[All figures magnified 20 diameters,] 



SETT. RES. Q- LASS- SANDS, PL. IV 



*- 





FTg. 1. Huttons Ambo Sand, 
before being washed. 



Fig. 2. Huttons Ambo Sand, 
after being washed. 





Fig. 3. Muckish Mountain Quartzite Fig. 4." Muckish Mountain Quartzite ; 

ordinary light. crossed nicols. Same field as Fig. 3. 




Fig. 5. Crushed Vein-Quartz, 
Achill Island (Quality 3). 




Fig. 6. Sand from King's 



Photomicrographs of Glass-Sands (reflected light);*/ - 

[All figures magnified 21 diameters.] - i / i " _1 



SUIT. RES. GLASS-SANDS, PL. V. 




X 21. 



Fig. 1. Sand from Berkeley Springs, West Virginia, U.S.A. 



r 







Fig. 2;^ Sand from Ottawa, Illinois (Wedron Silica Company), 
U.S.A. 

Photomicrographs of American Glass-Sands 
(reflected light). 



Hun: MKN. <V/..-i,s-,s-/?,;:V/;.v, JP/.. 7 r /. 




*.-'-* - 

-' '-.' 



/' 

tfv- 



* ; -/; 

*,^y -i*-. ; '*"*" J :' JA x 

; .' h ^. . -.-%*. IF.. 

. . , ' J ~"b 

, -.- -.,;:# ,*; 



J 2 

-d 



ho 




I!, 



f 

y 



SKIT. 



. Til: 




Rikof's Machine for the Washing of Sands. 

(Tha draimjg-oone shown in Kg. 18, p. 128, is partly obscured by the staging 
and is marked by a white dross.) 



Plate Yl 



SKETCH-MAP SHOWING THE OUTCROPS OF THE GEOLOGICAL 
FORMATIONS IN WHICH GLASS-SANDS OCCUR, AND ALONG 
WHICH THE EXTENSION OF SUPPLIES MAY BE EXPECTED. 

By Professor P.G.H.BOSWELL 



ENGLAND & WALES 




Bagahot Beds. etc. Oolite Somfc 

Qreenaonrf [>^^S| Tnewaic Sonrfs 

fl*o/s Sands for commm bottJe-gltus are not included. 



PlateX 

SKETCH-MAP SHOWING THE LOCATION OF THE CHIEF IRISH RESOURCES OF 
GLASS- SANDS IN RELATION TO THE GLASS-MAKING AREAS, 
COALFIELDS. RAILWAYS, AND INTERNAL WATERWAYS. 

By Professor P. G.H. BOSWELL. 




Glw-jnaking anas. 
i!iO CoaJFiettte. 

Gbw-sand producin. 



The depth of colour in tht gktM- making or&ta yields tut indication of the 
'. the greafoet depth of coJour reprettntiny 



fia.ilna.ys in red. 
Canals Waterways it 



nd produced the palest colour 





INDEX. 



Note. Descriptions of particular Glass-Sands, etc. occur on pages 
marked in black figures. 



Aberdeen, 17, 165. 

Abergele (Denbighshire), 79, 104, 

126, 141, 157, 164. 
Abrasive Sands, 3, 47, 59, 84, 97. 
Absorbent Sands, 5. 
Accuracy of Elutriation, 27. 
Achffl Island (Co. Mayo), 96, 128, 

145. See also Westport. 
Acid Treatment of Sands, 126. 
Agriculture, Irish Department of, 82. 
.Agriculture, Sands used in, 2. 
Air-blast, 124. 
Alderley Edge (Cheshire), 76, 141, 

142, 154, 162. 

Allahabad Glass Works, 189, 157. 
AUothigenous minerals, 10. 
Alaop en le Dale (Derbyshire), 102. 
Alum Bay, Isle of Wight, 72, 14,0, 

141, 145, 156, 163. 
Alumina-bearing Books, 14, 36, 42, 

89, 98, 99, 106, 127, 143, 158. 
AlnmiTiti., used in Glass-manufacture, 

107. 
American Glass-Sands, 34, 45, 48, 

120, 134, 135, 136, 137, 138, 169, 

170. 

Amlwch, Anglesey, 96. 
Ammonia, Use of in Elutriation, 22. 
Analyses of raw materials, 152. 
Anglesey, 96, 155. 
Angularity of Sands 2, 8, 12, 46. 
Antrim Co., Sands from, 77, 90, 

165. 

Apethorpe (Northants), 68, 148. 
Aplite, 106, 115, 129, 159. 
Apparatus required for Analysis, 

16, 21. 
Appin (Argyllshire), 95, 99, 129, 144, 

155 
Apted, A. B., 61. 



Archasan Rooks, 76, 143. See also 

Pre-Oambrian. 
Ardara, Maghera (Co. Donegal), 77, 

144, 154, 165. 
Arenig deposits, 141. 
Argyllshire, Quartzite from, 95, 99, 

129, 144, 155. 

Argyllshire, Pegmatites from, 114. 
Arkansas, U.S.A., 149. 
Arklow (Co. Wioklow), 97. 
Arkwrig-ht find Eapaport, 81. 
Arnold, Joseph, 51, 58, 156. 
Arsenic, Use of, 36, 42. 
Ashcroft, E. A., Process for extrac- 
tion of Potash, 118. 
Ashdown Sands, 35, 52, 54, 140, 141, 

142, 156, 162, 163. 
Ashford (Kent), 162. 
Ashgrove Loch (Kilwinning), 87. 
Ashurstwood (Sussez), 55, 141, 154, 

156, 162. 

Aughrim (Co. Wioklow), 113. 
Australia, Sands from, 139, 153, 

157. 

Authigenous minerals, 10, 117, 135. 
Average Diameter of Grains, 27. 
Aylesbury (Bucks), 12, 35, 47, 49, 50, 

51, 56, 119, 126, 140, 141, 142, 

148, 152, 156, 163. 
Ayleaford (Kent), 35, 62, 141, 142, 

156, 163. 
Ayrshire, Sand from, 87. 



BadcallPier (Sutherlandshire), 110. 
Bagshot Sand, 18, 35, 69, 71, 72, 73, 

140, 141, 154, 157, 163, 164. 
Baked Clay added to batch, 99, 

108. 
Balgownie Links (Aberdeen), 17. 



172 



INDEZ, 



BaUinderry E. (Cookstown), 91. 
Ballyoastle (Co. Antrim), 77, 90, 144, 

145, 155, 161, 165. 
Ballymanus (Go. Wicklow), 113. 
Ballymoney (Co. Antrim), 91. 
BallynesB (Oo. Donegal), 82. 
BallyphetriBli (Tiree), 165. ; 
'Ballyshannon (Co. Donegal), US. 
Baltimore, U.S.A., 138, 169, 170. 
Bank-end Farm, Kilwinning, 87. 
Banbnry, 69. 

Bardaey Island (CarnarronBliire), 

Vein-quartz from, 97. 
Barium Felspar (Celsian), 110. 
Bamsley Glass- Works, 40, 124, 132, 

146, 166, 167. 
Barton Sands, 70, 141 

Barytes, Cementing Sandstone, 36, 

143. 

"Batch" for Glass-making, 35. 
Bawsey Siding, near Lynn, 58. 
Bawtry (Yorkshire), 154. 
Bearsted (Kent), 63, 141, 156, 163. 
Bebington (Cheshire), 85. 
Bedfordshire, Sands from, 4, 44, 58, 

141. See also Leighton Buzzard. 
Beinn Ceannaheinne, Dumess, 110. 
Belfast, Bottle-making at, 85, 92, 

146. 

Belfast Lough, 157. 
Belfast, CoUin Glen, 117, 159. 
"Belgian Bed" Moulding - Sand, 29, 

30. 
Belgian Glass-Sands, 34, 44, 46, 49, 

50, 51, 56, 67, 126, 132, 147, 153, 

166, 167, 168. 
Belleek (Co. Fermanagh), 111, 112, 

113, 114, 160. 

Belleek Pottery, 111, 114, 160. 
Belmnllet (Co. Mayo), 114, 160. 
Berkeley Sand Co. ("W. Va.), 137, 

169, 170. 
Berkeley Springs (W. Vs.), 48, 137, 

149, 169, 170. 
Berkshire Sand Co., Cheshire, Mass., 

136, 169, 170. 

Bexhill (Sussex), 54, 154, 162. 
Birkenhead, 86. 
Birmingham, Glass-making at, 82, 

145, 146. 

Birmingham Public Library, 33. 
Birmingham Moulding-Sand, 30. 
Bisohof, C., 33. 

"Blaokfoot" Moulding-Sand, 73. 
Blaokgang Chine (Isle of Wight), 141, 

168. 

Blackheath (OldhaTen) Beds, 164. 
Blake Moor (Derbyshire), 102. 
Blatherwyke (Northants), '68, 143. 
" Blowing-out" of fine material, 45. 



Blown-Sands, 17, 32, 44, 77, 141, 

165. 

Blyth (Northumberland), 165. 
Boam, Joseph Ltd., 56, 154, 163. 
Bodmin (Cornwall), 107. 
Bohemian Glass, 35, 48. 
Solas, T., 38. 
Bottle-Glass, 35, 42, 43, 48, 56, 64 r 

66, 68, 73, 75, 76, 85, 89, 92, 99 r 

116, 142, 143, 146. 
Bovey Beds, 31, 101, 103. 
Brandenburg, Sand from, 36. 
Bramford (Suffolk), Glauoonite from,, 

117, 159. ' 

Brandy Gill, Granophyre from, 106, 

158. 
Brasaington (Derbyshire), 98, 103, 

157, 164. 

Braunkohle associated with Glass- 
Sands, 130, 140. 
Briok added to batch, 98. 
Brick-making, Sands for, 4, 29. 
Bridgwater Brick added to batch, 98, 

158. 

Bridport (Dorset), 45, 148. 
Brierley Hill (Staffs), Glass-making- 

at, 145. 

Bristol, Glass-making at, 71, 146. 
British Guiana, Sands from, 153. 
British Sands suitable for Glass- 
making, 49. 
British Silica and Minerals Co. Ltd.,, 

91. 

Brockenhurst (Hants), 73, 163. 
Bromley (Kent), 32, 164. 
Bromoform, Use of, in separating- 

minerals, 16. 

Brora, N.B., 90, 144, 154. 
Buckinghamshire, Sands from, 49, 51, 

141, 156, 163. 

Building-Sand, 4, 56, 58, 60. 
Bulverhyth (Sussex), 52, 54, 141 r 

154, 162. 
Bunter Sands, 74, 103, 141, 142, 154, 

162. 

Burleigh (Northants), 143. 
Burning of Sands, 125. 
Burns, J., 92. 
Burythorpe (Yorkshire), 32, 45, 49 r 

67, 68, 141, 156, 162. 
Burton (Derbyshire), limestone from, 

36. 



Calcareous Sands, 2, 42. 
Caloiferoua Sandstone, 91, 144, 145, 

154, 155, 161. 
Caloite in Sands, 42. . 
CaldweU, N.B., 86, 144, 154, 155, 

161. : 



INDEX. 



173 



Caldwell Sand Co. Ltd., 86. 
Callovian Sand, 32. See also Bury- 

thorpe. 

Comas, Eigg, 77, 165. 
Cambrian Books, 134, 136, 14,4, 169, 

170. 

Campine (Belgium), Sand from, 132. 
Canal-transport, 146, 150. 
" Candle Clays," 101. 
Cantor Lectures on Optioal Gloss, 

49. 
Carbonaceous matter associated with 

Sands, 11, 51, 52, 90, 101, 103, 

130, 140. 
Carboniferous Limestone, 5, 83, 104, 

141. 
Carboniferous Limestone, Hollows in 

surface, 102, 104. 
Carboniferous Limestone Series 

(Scotland), 86, 87. , 
Carboniferous Sandstones, 77, 82, 83, 

84, 86, 87, 88, 89, 90, 91, 104, 

134, 135, 143, 144, 145, 154, 155, 

161. 

Carboniferous System, alumina- 
bearing Sands from, 98. 
Carborundum, Sands for making, 

3. 

Cardiganshire, Rooks from, 97, 164. 
Carnarvonshire, Hooks from, 97. 
Carsington Pastures (Derbyshire), 

103, 164. 

CastlecaldweU (Co. Fermanagh), 111. 
Castiefreke (Cork), 78. 
Castle Howard (Yorkshire), 66. 
Caswiok (Northants), 143. 
Caterham (Surrey), 60. 
Celsion (Barium Felspar), 110. 
Cement, Sands for, 4. 
Cements of Sandstones, 11. 
Ceramic Society (American), 34. 
Ceramic Society (English), 83, 34. 
Champagne, Sands from, 35. 
Chance's Quarry (Leighton Buzzard), 

58. 
Channel Islands, GHauoonite from, 

117. 

Chapel Combe (Cornwall), 101. 
Charlton (Kent), 29, 45, 50, 73, 98, 

141, 156, 164. 
Cheltenham, 143. 
Chemical Analyses, 121, 154, 155, 

156, 166, 168, 169. 
Chemical Composition of Glass-Sands, 

41. 
Chemical research on Glass, 142, 

151. 

Chemical Ware, 35, 100, 145. 
Cherry Garden (Ashuretwood), 55. 
Cheshire, Mass., 136, 169, 170. 



Cheshire, Sands from, 45, 84, 141, 

142. See also Spital. 
Chesterfield Canal, 75. 
China-clay, 9, 98, 100, 101, 107. 
Ohina-olay, Felspar and Silioa Co., 

Ltd., 93. 
China-stone, 114, 115, 128, 154, 

159. 

Classification of Grades, 13. 
Clayoastie, Toughol, 78. 
Clay grade, 9, 11, 100, 124. 
Cliff-End, Winohelsea, 53. 
Clonakilty (Co. Cork), 154. 
Cluff, R., 91. 

Clyneleish Quarry, Brora, 90. 
Coalisland, L. Neagh, 77. 144, 165. 
Coal-Measure Sandstones, 12, 79, 82, 

91, 140, 141, 155, 161. 
" Coarse Micas," 100, 159. 
Coating on Sand-grains, 11, 17. 
Colcerrow (Cornwall), 159. 
Cole, Prof. G. A. J., 113. 
Coleroine, 93. 
Collin Glen, near Belfast, Glauoonite 

from, 117, 159. 
Colonial Sands, 139, 140, 153, 157, 

165. 

Colouring of Gloss, 37. 
Colour of Glass-Sands, 119. 
ColumbHQe (Co. Donegal), 113, 160. 
Combustion-tnbing, 35. 
Composition of Sands, 1, 9. 
Concrete, Sands for, 4, 58. 
Connemara Quartzite, 155. 
Continental Glass-Sands, 89, 130, 147, 

149, 150, 160, 166, 167. 
Continental Glauconites, 117. 
Conway, 104. 
Cookstown (Co. Tyrone), 91, 145, 

154, 155, 161. 
Coolkeeragh (Co. Londonderry), 92, 

121, 145, 154, 155, 161. 
Oorallian Sands, 4, 90, 143. 
Gorby (Northants), 68, 141, 162. 
" Oordy" Glass, Cause of, 38. 
Core-Sands, 5. 

Cork Co., Sands from, 78, 145. 
Cork Exhibition (1902), 82. 
" Cornish Red" Moulding-Sand, 29. 
Cornwall, Rocks from, 5, 9, 29, 32, 

100, 101, 107, 113, 154, 159, 160. 
Cost of foreign Sands, 147. 
Cotteswold Sands, 32, 45, 143. 
Cowie, N.B., 89. - 
Crank (Lanes), 64, 141, 142. 
Greeohbarrow (Dorset), 73. 
Cretaceous Deposits, 3, 4, 9, 81, 141. 
(See also Greensanda and Weolden.) 
Croagh More (Co. Fermanagh), 112. 
Crofthead, N.B., 88. 



174 



INDEX. 



Crook's Elntriator, 21, 22, 25. 
Crook, T., on Sands, 17. 
Crucible-making, Sands for, 5. 
Crushing of Rooks, 48, 79, 128. 
Crushing Strengths, 86, 95, 128, 

129. 

Cryolite, 86. 
"Crystal" Ware, 37, 48, 128, 145, 

152. 

Culbin (Nairn), 165. 
Culm Shalea (Carboniferous), 115. 
Curracloe, Eoaalare, 77, 165. 
"Cut-glass," 37, 47, 48, 128, 137, 

145, 152. 



Daliadian Books, 77, 81, 98, 95. 
Danish Glass-Sands, 34, 45, 168. 
Dartmoor, Alumina - bearing Sands 

near, 9, 101. 

Dartmoor Granite, 9, 101, 115. 
Davidson, J~. H., 75, 94. 
Decolorisers of Glass, 37, 42. 
Decorative "Ware, 145. 
Denbighshire, Sandstone from, 104, 

141, 164. 
Denford (Northants), 68, 141, 143, 

156, 162. 
Denmark Geological Surrey. 28, 34, 

168. 

Deposition of Sands, 8. 
Deposits carrying Alumina and 

Silica, 98. 

Deposits in North Wales, 104. 
Derby Glass-works, 40, 85, 145, 166, 

167. 
Derbyshire, Sands and Books from, 

5, 36, 85, 102, 141, 144, 157, 

164. 
Derrylogan (Co. Donegal), 113. 

160. 
Derryrona (Co. Fermanagh), 111 

160. 

Desert-Sands, 12. 
Detrital Minerals, 10, 43. 
Devon, Kaolin from, 100. 
Devon, Refractory Sands from, 5, 32 

101. 

Devon, Aplite from, 115, 159, 161. 
Devonian Rocks, 143. 
" Devonshire Hard Purple Stone " 

115. 

Diatomite, 5. 
Dinas bricks, 38. 
Distribution of Glass - making in 

British Islea, 145. 
Dog-Trap Gully, Victoria (Australia), 

139, 157, 165. 
' Dominant Diameter," 28. 
Donegal, Pegmatites from, 114, 160. 



Donegal, Rocks from, 77, 81, 112, 

113, 154, 155, 160, 161, 165. 
Dooey (Co. Donegal), 114. 
Doolough (Co. Mayo), 114, 160. 
Dorentrup (Saxony), 130. 
Dorset, Sands from, 45, 68, 73, 140, 

143. 

Down, Co., Sands from, 165. 
Downie, W. Maoalpine, 95. 
Downton (Hants), 72. 
Dralle, R., 33, 35. 
Drift-sand, 77 See also Glacial 

Deposits. 

Drying of Sands, 120, 124. 
Dry-screening of Sands, 125. 
Dublin, Glass-making at, 77, 85, 

146. 

Dublin Co., Sand from, 77, 165. 
Dudley, Glass-making at, 145, 146. 
Dune-Sands, 9, 17, 43, 44, 49, 76, 

142, 144. 

Dunfanaghy (Co. Donegal), 82. 
Dumess (Sutherlandshire), 109, 110, 

160. 
Dutch Glass-Sands, 44, 49, 50, 126, 

133, 147, 158, 166, 167. 



Eaglesoliffe "Sand," 99, 127," 154 r 

156, 162. 

East Anglian Sands, 2. 
East Grinstead (Sussex), 55. 
East Hoathly, 162. 
East Mills, Fordingbridge, 72. 
East Wickham (Kent), 164. 
Ebbw Vale Steel Co., 68. 
Economic Considerations, 41, 147. 
Edinburgh, Glass-making at, 89, 145, 

146. 
Edinburgh and Leith Glass- Works, 

40, 133, 166, 167. 

" Effective size " of Sands, 28. 
Egg-timers or " egg-boilers," Sands- 

for, 4, 146. 
Eigg, KB., 77, 16B. 
Electric Globes, 37, 42, 142, 146. 
Electromagnetic treatment of Sands, 

etc., 17, 80, 128, 149. 
EUworthy, T. W., 54. 
Elntriation, 20, 43. 
Elutmtors, 21. 

English Glass-Sands, 43, 141. . 
English Ceramic Society, 33, 34. 
Eocene Deposits, 3, 29, 31, 45, 69 r 

71, 72, 73, 141, 142, 154, 156. 

163. 

Eriboll (Sutherlandshire), 109. 
Erith Moulding-Sand, 29, 30, 73. 
Ends Head (Co. Mayo), 114, 160. 
Estuarine Series, 68, 140, 141, 143. 



INDEX. 



175 



Etching of Glass, 47. 
Etruria (Staffs), 160. 
European Glass-Sands, 39, 130, 132, 

133, 134, 153, 166, 167, 168. 
Everett, J. D. and A., 33, 36. 
Examination of Sands under the 

microscope, 17. 

Exportation of Sands, 73, 150. 
Extraction of Potash from Silicates, 

118. 



Facing-Sands, 5. 

Fsen0 (Denmark), 168. 

FairHght (Sussex), 49, 52, 54, 141, 

154, 156, 163. 
Fauldhouse, N.B., 88. 
Felsites, 106, 158. 
Felspar, 9, 17, 35, 36,42, 43, 56,106, 

107. 
Felspar - bearing Books, 107, 108, 

109, 110, 111, 112, 113, 114, 

160. 

Felspar used in Glass-making, 106, 
Fenner, On behaviour of Silica, 80. 
Fermanagh, Bocks from Co., Ill, 112, 

113, 160. 

Fertilizing, Sands for, 3, 117, 159. 
Fettke, On American Glass-Sands, 

34. 

Fettling Furnaces with Sands, 5, 7. 
Filtration-Sands, 5, 58, 95, 136. 
" Fining " of glass, 38, 128. 
Fintown (Co. Donegal), 114. 
Fire-bricks, 38. 
Fire-bricks, Sands for, 5. 
Fire-clay, 38. 
Firth of Forth, Glass-making near, 

146. 

" Flashing," 37. 

Flint-glass, 7, 35, 48, 142, 146. 
Flintshire, Sandstone from, 83, 104, 

141, 164. 
Flitwiok (Bedfordshire), 59, 156, 

163. 

Fluorspar, 36. 
Folkestone, 159. 
Folkestone Beds, 60, 61, 62, 63, 156, 

103. 
Fontainebleau Sand, 12, 32, 35, 39, 

40, 42, 44, 46, 47, 48, 50, 53, 56, 

60, 61, 67, 126, 132, 140, 147, 149, 

151, 152, 166, 167. 
Fordingbridge (Hants), 71, 141, 154, 

157. 
Foreign Glass- Sands, 34, 50, 130, 

166, 167, 169, 170. 
Forest Row (Sussex), 55. 
Form of Sand-grains, 12. 
Formation of Sands, 8. 



Formulsa in Glass-making, 34. 

Foundry-Sand, 5, 56, 58. 

Fox, E. B. Colton, 68. 

Fox Cover Pit, Borythorpe, 67. 

Foxhall (Suffolk), 13, 32. 

Fox Boy and Co. Ltd. (Meldon Book), 
115. 

Foyle, Biver, Sand from, 92, 144. 

France, Sand from. See Fontaine- 
bleau. 

Frazer and others, Extraction of 
Potash from Felspar, 118. 

Friction- Sands, 3. 

Friden (Derbyshire), 102. 

Fuel, Consumption of, in Glass- 
making, 145, 146. 

Furnace-Sands, 5, 56, 66, 91, 144. 

Furnaces for Glass-making, 37, 38. 



" Gannister," 82, 95, 96, 102. 

Garside, G., 58, 156, 163. 

Garvary Wood (Co. Fermanagh), 112, 

160. 

Gateshead, Glass-making at, 146. 
Gauge-glasses, 146. 
Gay and Wilson, 58, 154, 163. 
Gayton (Norfolk), 56. 
Geological Survey of Denmark, 28, 

34, 168. 

Geological Survey of Great Britain, 

35, 100, 101, 109, 110, 115, 118, 
160. 

Geological Survey of ludia, 139, 

157. 
Geological Survey of Ireland, 111, 

113. 
Geological Survey, TT.S.A,, 28, 34, 46, 

47, 118, 134, 169. 
German Glass-Sands, 35, 49, 130, 

166, 167, 168. 
Gerner B., 33. 
Gilbert, E., 73. 
Glacial Deposits, 3, 4, 29, 58, 64, 

126, 140, 141, 142, 154, 157, 165. 
Glasgow, Glass- making at, 145, 

146. 
Glasgow, Sandstones from, 86, 87, 

143. 

Glass-making, Distribution of, 145. 
Glass-manufacture, Process of, 33. 
Glass-Sand, Ideal, 31, 48. 
Glass Technology, Department of 

University, Sheffield, 75, 94. 
Glass Technology, Society of, 33, 34, 

134. 
Glauoonitio Sands, 3, 57, 117, 118, 

159. 

Glaze, Sands used for, 4. 
Glenbeigh (Kerry), 78. 



IBDEX. 



Olenboig, N.B., 38, 89, 144, 154 t 

181. 

Glenties (Co. Donegal), 114. 
Gobb, Ballyoastle, 90. 
Oodatone (Surrey), 49,50, 60, 61, 63, 

67, 126, 141, 142, 156, 163. 
Goodwyn and Sons, 60. 
Orade-aizes, 13. 
Grading of Sands, 2, 8, 43. 
Granham'e Moor Quarries, Pontea- 

bury, 95. 
Granite, 5, 100, 106, 108, 115, 129, 

159. 

Granophyre, 106, 158. 
Graphical expression of Mechanical 

Analyses, 28. 
Gravel, 9, 13. 

Great Haldon Bolls (Devon), 31. 
Oreensands, 3, 4, 57, 117, 118, 159. 
See also tipper Greensand and 
Lower Greensand. 
Grejs Dal (Denmark), 168. 
Grejs Mjzflle (Denmark), 168. 
Griffin Mine, BallycastLe, 90. 
Grinding of Glass, 47, 59. 
Grinding of Glass-Sands, 47. 
Gniaeley (Yorkshire), 79, 80, 82, 141, 

154, 155. 

Gniseley Gannister Co., 82. 
Oweebarra (Co. Donegal), 114, 160. 



Hailes, KB., 89, 144. 

Halkyn Monntain (Flintshire), 104. 

Hampshire, Sands from, 69, 71, 72, 

73, 141, 142, 154, 156, 157, 163, 

164. 
Harborongh Books (Derbyshire), 

102. 

Harris, Gregory, 58, 163. 
Hartiepool (Durham),, 165. 
Hartwell siding, near Ayleabury, 52. 
Hasketon (Suffolk), 29, 30. 
Hastie, A. H., 55. 
Hastings Sands, 52, 54, 141. See 

also Ashdown and Tnnbridge Wells 

Sands. 

Hatherleigh (Devon), 101. 
Hazen on Grade-size, 28. 
Headon Hill Sands, 72, 140, 141, 156, 

163, 164. 

Heathfield (Devon), 101. 
Heavy Liquids, 16. 
Heavy Minerals in Sands, 9, 10, 16, 

125. 
Heokie, Alton and Kerr (Ballyoastle), 

90. 
Hematite coating Sand-grains, 11, 41, 

119, 125. 
Henrivanx, J., 33. 



TTigha. (Kent), Glass-making- at, 

74. 

Higher Bebington (Cheshire), 85. 
High Peak (Derbyshire), 102, 157, 

164. 

High Silica Sands Co., 65. 
Hohenbocka (Prussia), 12, 35, 41, 

130, 140. 

Hohlbanm, R., 33. 
Holland, Sands from, 34. 
Hollingbonrne (Kent), 63, 141, 142, 

156, 163. 
Holyhead Monntain (Anglesey), 96, 

100,101,129,155. 
Horn-glasses, Sands for, 3. 
Hovestadt on Jena Glass, 33, 36. 
Howe, J. Allen, 100, 102. 
Huttons Ambo (Yorkshire), 49, 65, 

98, 99, 121, 143, 154, 156, 162. 
Hvidbjerg (Denmark), 168. 
Hydrochloric acid for cleaning 

Sands, 126. 



Ideal Glass-Sand, 31, 48. 

Ideal Moulding-Sand, 31. 

Ignition of Sands, 125. 

LUing, V. 0., 125. 

Illinois, U.S.A., 135, 136, 149, 169, 

170. 

Djnenite in Sands, 43, 65. 
Importance of Sand in Glass-making, 

35, 45. 
Importation of Sands, 34, 147, 150, 

151. 

Impurities in Sands, 11, 151. 
Inohard, Loch (Sutherlandshire), 

109. 

Inchnadamff (Sutherlandshire), 155. 
Indian Sands, 139, 153, 154, 157, 

165. 
Inferior Oolite, 18, 45, 65, 68, 69, 

140, 141, 142, 143, 156, 162. 
Institute of Chemical Glass-formula, 

34. 

Institute of Chemistry, 34. 
Institution of Mining and Metallurgy ; 

Screens, 19. 
Iowa, U.S.A., 149. 
Ipswich, 29, 30. 
Ireland, Pegmatites from, 111, 112, 

113, 160. 
Ireland, Sands from, 43, 77, 90, 91, 

92, 93, 97, 134, 144, 155, 157, 158, 

159, 161, 165. 

Irish Glass Industry, Ancient, 145. 
Irish Industrial Minerals Co. Ltd., 

96. 
Iron-bearing Minerals, 10, 110, 

113. 



INDEX. 



177 



Iron, Impurity due to crushing, 83, 

96. 

Iron, Impurity in Glass, 87. 
Iron, Impurity in reagents, 15. 
Iron oxide in Sands, 10, 11, 14, 87, 

119, 151, 154. 
Iron-percentage in Glass-sands, 41, 

42, 48. 

Islay, N.B., 95, 144, 165. 
Isle of Eigg, 77. 
Isle of Jura, 76, 77, 95, 144, 157, 

165. 
Isle of Wight Sands, 34, 70, 72, 73, 

140, 141, 142, 145, 156, 163, 

164. 



Jaokson, Sir Herbert, 151. 

Jena Glass, 33, 35. 

Jenkinson, S. N., 40. 

Jet-holes, Size of, for Elutriators, 

25. 

Jubbulpore, India, 139, 157, 165. 
Juniata White Sand Co., Baltimore, 

Md., 138, 169, 170. 
Jura, N.B., 76, 77, 95, 144, 157, 

165. 
Jurassic Deposits, 65, 67, 68, 140, 

143, 154, 156. 



Kaolin, 36, 100, 116. 
Kaolin-bearing Sands, 5, 9, 32, 46, 

85, 93, 94. 

Keilhaok K., on Elutriation, 23. 
KeUoway Beds, 32, 45, 50, 66, 67, 68, 

141, 143-, 156,. 162. 
Kent, Sands from, 29, 32, 45, 62, 63, 

73, 74, 141, 142, 156, 163, 164. 
Ken-fallen (Argyllshire), 95. 
Kerniok (Cornwall), 108, 160. 
Kerry Co., Sanda from, 78. 
Keuper Marls, 4, 103. 
Keuper Sandstone, 76, 85, 141, 142, 

156, 162. 
Kieselguhr, 5. 

Kilbarriok, Sutton (Dublin), 77. 
Kildownet (Aohill Island), 97. 
Kilkee (Kerry), 78. 
Killieorankie, N.B,, 144. 
KUwinning, N.B., 87, 144, 155, 

161. 

Kinahan, G. H., 77, 113. 
Kingsoavil, N.B., 89, 144. 
King's Lynn (see Lynn). 
Kings Moss (Lanos), 64. 
Klondike, Mo., 169. 
Knottingley Glass -Works, 132, 133, 

166, 167. 
Kynance Cove (Cornwall), 29, 30. 



Laboratory-ware, 35, 87, 42, 57, 59, 

61, 100, 142, 145. 
Laggas Bay, Islay, 165. 
Laig Bay, Eigg, 77, 165. 
Lancashire Sands, 3, 64, 121, 140, 

141, 142, 157, 165. 
Twit-hill (Co. Fermanagh), 112. 
Larson, On Behaviour of Silica, 80. 
Laxf ord Looh (Sutherlandshire), 109, 

110, 160. 

Leavening (Yorkshire), 162. 
Lee, Cecil, 71. 

Leeds, Glass-making at, 146. 
Leeds Public Library, 33. 
Leighton Buzzard (Bedfordshire), 44, 
47, 50, 58, 61, 67, 119, 121, 127, 
140, 141, 154, 156, 163. 
Lemgo (Westphalia), 35. 
Lenses, 146. 
Lermantoff, W., 33. 
Levenseat, N.B., 88, 98, 144, 155, 

161. 

Lewisian Gneiss, 109. 
Lighting Glass, 37, 42, 57, 119, 142, 

146. 
Lignites associated with Glass-Sands, 

52, 132, 140. 
Limerick, 145. 

Limestone in Glass-making', 36. 
Limonite coating on Sand-grains, 11, 

41, 45, 119, 125. 
, Limpafield (Surrey), 60. 
LinlithgowBhire, Sand from, 89. 
Lincolnshire, Sand from, 165. 
Lippe Sand, 12, 27, 48, 49, 50, 130, 

140, 149, 166, 167. 
Literature on Glass-Sands, 33. 
Little Haldon Hills (Devon), 31. 
Llandudno, 104. 
Lleyn Peninsula, Vein-quartz from, 

97. 
Location of British Glass-Sands, 

140. 

Loohoraigs Farm, Kilwinning, 87. 
London, Glass-making in, 52, 54, 60, 

73, 82, 145, 146. 
London Basin, Sands of, 73. 
London Clay, 4, 29. 
Londonderry, 92, 112, 154. 
Longoliffe (Derbyshire), 103, 144, 

164. 
Longdown (Hants), 69, 141, 154, 

157. 
Lower Estuarine Sands, 162. See 

also Corby. 
Lower Greensand, 3, 4, 49, 50, 51, 

58, 58, 59, 60, 61, 62, 63, 119, 

126, 141, 142, 144, 154, 156, 163. 
Lower Kildress, Oookstown, 91. 
Lower Oolites, 65, 68, 141. 



178 



INDEX. 



Low Moor (Derbyshire), 102, 141. 

Luxullian (Cornwall), 160. 

Lyle, Capt. S. J., 90. 

Lymington (Hants), 73, 164. 

Lynn (Norfolk), 27, 30, 35, 44, 47, 

49, 50, 56, 67, 141, 142, 145, 154, 

156, 163. 
Lyon, T. H., and Partner, 68. 

MacriliaiiiBh Bay (Argyllshire), 165. 
Maghera, Ardara (Oo. Donegal), 77, 

154, 165. 

Magnetic separation, 17, 97. 
Magnetic treatment of Sands, 17, 80, 

127, 128, 148. 

Maiden Bradley (Wilts), 159. 
Maintenon (Prance), 35. 
Malton (Yorkshire), 45, 50, 65, 67. 
Manchester, Glass-making at, 76, 

145, 146, 167. 

Manchester Pnblic Library, 33. 
Manganese dioxide, Use of, for de- 
colorising, 37, 42. 
Marson, P., 33. 
Martinroda (Saxony), 36. 
Maryland, "U.S.A., Sand from, 138, 

169, 170. 
Massachusetts, Sand from, 136, 169, 

170. 

Maw, George, 102. 
Mayo, Books from, 93, 96, 114, 

160. 
Mechanical Analyses, 18, 121, 161, 

167,168,169,170. 

' Mechanical Composition of Glass- 
Sands, 43. 

Medical apparatus, 146. 
Medway, E., 63. 
Meldon Eock, 115, 128, 129, 154, 

159, 161. 
Memoirs, Geological Survey of Great 

Britain, 35, 36, 52, 61, 68, 64, 

70. 

Mersey, E., 47, 64. 
" Metal " in Glass-making, 35. 
Methods of investigating sands, 14. 
Mica in Sands, 12, 43, 68, 101. 
Micaceous Sands, 68, 71. 
" Micas " of China-clay works, 100, 

116, 159. 

Miorocline, 3, 109. 
Miorogranite, 106. 
Microscopic examination of Sands, 

17. 

Middleton (Norfolk), 56. 
Middle Oolites, 141, 142, 144. 
Midford (Somersetshire). 45, 143. 
Midland Valley of Scotland, 89. 
Mile Tree (Leighton Buzzard), 58. 



Miller, J. B., 33. 

MiUisle (Co. Down), 144, 165. 

Millstone Grit, 85, 88, 104, 144. 

Minera (Denbighshire), 84, 141, 161. 

Mineral Analyses, 15. 

Mineral Composition of Sands, 10, 

43. 
Mineral Impurities in Glass-Sands, 

43. 

Mineral Milling Co., Mold, 83. 
Miner's Lamps, Glass for, 35. 
Minnesota, "U.S.A., 149. 
Miocene Deposits, 81, 101, 130, 144, 

157. 
Mississippi Basin, Glass-sands of, 

124, 149. 

Missouri, U.S.A., 149. 
" Mixed Stone " for Pottery work, 

114. 

Moine Schists, 109. 
Mold (Flintshire), 83, 141, 154, 155, 

161. 

Monazite-bearing Sands, 2. 
Monorieff, J. Ltd., for Elutriators, 

21. 

Montana, Sands from, 188, 169, 170. 
Montrose, 32, 165. 
Morgan, Prof. Gilbert, 77. 
Mortar, Sands for, 4. 
Moulding-Sands, 5, 29, 31, 73, 75. 
Mow Cop (Cheshire), 84, 155, 161. 
Muckish Mountain (Co. Donegal), 

77, 79, 81, 126, 145, 154, 155, 

161. 

Mud-grade, 13. 
Muller, B., 33. 
Muscovite Mica, 116. 



Nature of Sands, 8. 

Neagh, Lough, 77, 165. 

Nemours (France), 35. 

Newbald (Yorkshire), 68. 

New Forest (Hants), 70. 

Newhaven (Derbyshire), 103, 144, 

157, 164. 
Newport (Mon.), Glass-making at, 

146. 

Newton Abbot (Devon), 101. 
Nioopits Sand Co. Ltd., 62. 
Nievelstein (Ehine Province), 35,. 

41. 

Nitre-cake for bleaching Sand, 126. 
" No Man's Land," 71. 
Non-graded Deposits, 9, 31. 
Non-graded Materials, 79, 80. 
Norfolk, Sands from, 27, 30, 35, 44, 

49, 56, 58, 60, 67, 85, 141, 142, 

145, 154, 156, 163. 
Northamptonshire Ironstone, 68. 



INDEX. 



17& 



Northampton Sands, 35, 143. 
Northamptonshire, Sands from, 68, 

141, 143. 

North Wales, Sands from, 104. 
Norton Tunnel, 75. 
Norway, Felspar from, 107, 111. 
Nottinghamshire, Sands from, 45, 

74, 76, 99, 141, 142, 154, 162. 



Obsidian, 42. 

Okehampton (Devon), 115. 
Oldbury, Glass-makhig at, 146. 
Oldhaven (Blackheath) Beds, 32. 
Old Irish Glass, 145. 
Oligooene Strata, 39, 144. 
Oolites, 141. 
Optical Glass, 37, 47, 48, 82, 128, 

145, 151, 152, 153. 
Optical Society, Trans., 34. 
Ordovioian Rocks, 95, 141, 144, 155. 
Organic matter in Sands, 5, 11, 119. 
Origin of Sanda, 8. 
Oriskany Sandstone (U.S.A.), 137, 

138, 149. 
Orthoolane, 3. 
Ottawa, Illinois, 120, 135, 13C, 169, 

170. 

Ottawa Silica Co., HliiioiH, 135. 
OverHcaig (Suthorlandehire), 109, 

160. 

Oxfordshire, Sands from, 4. 
Oxted (Surrey), 60, 141, 163. 



Pacific, Mo., 138. 

Page, E,, Woodenbridge (Co. Wick- 
low), 97. 

PaltBOZoio Books, 143. 

' Panning " of Sands, 15. 

Pant dn (near Mold), 84, 104. 

Par (Cornwall), 115, 128, 154, 159. 

Paris, Sand from near, 39. 

" PaiTot," 90. 

Parsley Hay (Derbyshire), 98, 102, 
103, 141, 144, 157. 

Parting-Sands, 4. 

Patent Office Library, 33, 34. 

Patent Specifications on Glass, 33. 

Pirrit, W. P., 86. 

Pittsburg Plate Glass Co., Montana, 
169. 

Peaty matter in Sands, 51, 64, 69, 71, 
140. 

Pebble-bed, Bunter, 103. 

Peddle, C. J., 121, 124. 

Pegmatites, 42. 107, 108, 109, 110, 
111, 112, 113, 114, 129, 160. 

Periodicals on Glass-making, 34. 

Permian Marls, 74. 



Permian Sands, 119, 143, 154. 
Perth, Glass-making at, 145, 146. 
'Pharmaceutical Glass, 100, 142. 
Plate Glass, 47, 57, 146. 
Plean, N.B., 88, 89, 129, 144, 161. 
Pliocene Deposits, 29, 31, 101, 138. 
Pontefraot, 154. 
Pontesbury (Salop), 95, 155. 
Pool and Co. Ltd., for Screens, 19. 
Port-a-oloy (Co. Mayo), 79, 80, 93, 

99, 100, 121, 145, 154, 155, 161. 
Porth Wen, 96. 

Portland Cement, Sands for, 4. 
Portland Sands, 143. 
Portrush (Co. Antrim), 144, 165. 
Potash extraction from Silicate a, 

118. 

Potash Felspars, 86, 42, 107. 
Potash - bearing Books, 106, 158, 

160. 

Potash-bearing Sands, 3, 116. 
Pot-furnaces, 37, 45, 145. 
Potteries, 4, 114, 160. 
Powell, H. J., 83. 
Pre-Cambrian Pegmatites, 109. 
Pre-Oambrian Books, 79, 81, 93, 95, 

96, 101, 109, 113, 144, 154, 155, 

161. 
Precautions in Chemical Analyses, 

15. 
Pre-Glaoial Deposits of doubtful age, 

141. 

Pressed-ware, 59, 61, 142, 146. 
Process of Glass-making, 37. 
Producer-gas in Glass-making, 37, 

145. 

Production of Sand, 150. 
Profit on Glass-Sands, 148. 
Prussia, Sands from, 12, 35. 
Pulps from Gold-bearing Books, 24, 

153. 
" Purple Stone " for Pottery-work, 

114, 115. 

Pyrite in Glass-Sands, 135. 
Pyrogallol, Use of in Elutriation, 22. 



Quartz, 1, 3, 5, 9, 12, 14, 16, 27, 36, 
41, 43, 47. See also Vein-quartz. 

Quartzites, 36, 77, 79, 81, 93, 94, 95, 
96, 143, 145, 155. 

Quartz-Porphyry, 42. 

Queenborough, Glass-making at, 74, 
146. 



Badley, E. G., Analyst, 109. 
Bainford (Lanes), 64, 121, 141, 154, 

157, 165. 
Bapaport, Arkwright and, 81. 



CHECKED 2000 

IgQ 



INDEX. 



Raw Materials for Glass-making, 35. 
Recent Sands, 77, 141, 164, 157, 

169. 

Recuperative Furnaces, 38. 
Bed Crag Sands, 13. 
Redhffl (Surrey), 61, 62. 
Refractory Clays, 101. 
"Refractory Minerals, 43. 
Refractory Sands, 3, 5, 51, 52, 55, 56, 
58, 60, 61, 62, 63, 65, 73, 74, 81, 
82, 83, 84, 85, 86, 88, 90, 91, 95, 
101, 102, 120, 128, 152, 154, 155, 
156, 161-167. 

"Regenerative Furnaces, 38. 

Reid, Hugh, 89. 

Reigate (Surrey), 49, 61, 63, 126, 
141, 142, 145, 156, 163. 

Renfrewshire, Sand from, 86. 

Requirements of Glass-Sands, 39. 

Resistance Glasses, 35, 36, 48. 

Retgers on Dune-sands, 43. 

Rhffltic Shales, 103. 

Rhes y oae (Flintshire), 104, 141, 
164. 

Rhine Province, Sands from, 35, 41. 

Rhodin, J.Q-.A., Patent for Bleaching- 
aands, 126. 

Rhodin, J. G-. A., Patents for Extrac- 
tion of Potash, 118. 

Ribden (Staffs), 102, 141, 144, 154, 
164. 

Ries, H., On Clays, 23. 

Ries, H., On Sands, 28. 

Rikofs Washing Machine, 57, 122. 

Road-dressing, Sands for, 4. 

Roche (Cornwall), Felspar from, 107, 
160. 

Roche, " Micas " from, 100, 159. 

Rochester (Kent), 74, 141. 

Rogate (Sussex), 61, 163. 

Rome, Glauconite from, 117, 

Rookery (Lanes), 64. 

Rosenhain, Dr. W., 33, 49, 130. 

Rosslare (Co. Wicklow), 77, 144, 
165. 

Rouen, 39. 

Rounded Sand-grains, 27, 135, 136. 

Rounding of Grains, 2, 12. 

Rowsley (Derbyshire), 85. 

"Ruby" Glass, 87. 

Ruahmere (Waterford), 78. 

Rutile, 10, 43, 94. 



St. Agnes (Cornwall), Refractory 

Sands from, 101. 
St. Erth (Cornwall), 29. 
St. George's Hill (Surrey), 73, 164. 
St. Helens, Glass-making at, 64, 99; 

146. 



St. Ives (Cornwall), 165. , 

St. Keverne (Cornwall), 31. 

St. Leonards (Sussex), 54. 

St. Louis (TLSA.), 138, 169, 170. 

St. Peter's SandstonS (TT.S.A.), 135, 

138, 149. 
Salisbury, 71. 
Salmon, H. H., 69. 
Sancton (Yorkshire), 68. 
Sand-blast, 47. 
Sand-dunes, 12. 
Sandell Bros., 69. 
Sandfields, Ardara (Co. Donegal), 77, 

165. 
Sand-grade, 13. 

" Sand-paper," 7. 
Sandringham Sands, 44, 56, 58. 

Sands for Abrasive purposes, 3, 47, 
59, 84, 97. 

Sands for Absorbent purposes, 5. 

Sands for Agricultural purposes, 2. 

Sands for Brick-making, 4, 29. 

Sands for Building purposes, 4, 56, 
58, 60. 

Sands for Crucible-making, 5. 

Sands for Filtration, 5, 58, 95, 136. 

Sands for Fire-bricks, 5. 

Sands for making Carborundum, 8 

Sands for making 1 Cement, 4. 

Sands for making Concrete, 4, 58. 

Sands for Mortar, 4. 

Sands for Refractory purposes, 5. 

Sands for Silica-bricks, 5, 36, 96. 

Sands for Silicate of Soda (' "Water- 
glass"), 3. 

Sands for Soap-making, 3. 

Sandstone, 36. 

Sandstones, Crushing strength of, 
129. 

Sandymonnt Strand (Dublin), 77, 98, 
144, 157, 165. 

Saxony, Sands from, 12. 

Scandinavian Felspars, 111, 114, 
160. 

Scardans Lower (Co. Fermanagh), 
111, 160. 

Sohoene Elutriator, 21, 26. 

Scientific Glass, 145. See also La- 
boratory-ware. 

Soolban, Lough (Co. Fermanagh), 
. 111. 

Scotland, Glass-sands from, 43, 144. 

Scotland, Pegmatites from, 109, 110, 
160. 

Scouring-sand, 3, 61. 

Screening of Sands, 19, 122, 123, 
124, 161. 

Sonnthorpe (Linos), 165. 

Secondary Minerals, 11. 

" Seeds " in Glass, Cause of, 46. 



INDEX. 



181 



Selenium in Glass, 42. 
Shape of Grains, 41, 46. 
Sheet-Glass, 48, 49, 61, 146. 
Sheffield, Sand from works, 1H7. 
Sheffield, Sand from near, 74, 75. 
Sheffield University, Department of 

Glasa Technology, 75, 94. 
Shell Sands, 2. 

Shenley Hill (Leighton Buzzard), 58. 
Shenatono, W. A., 38. 
Shin, Looh (Sutherlandshire), 109. 
Shirdley Hill (Lanos), 64, 121, 142. 
Shore-Sands, 2, 9, 29, 43, 44, 49, 76, 

77, 141, 142, 144, 154, 157, 165. 
Shropshire, Quartzite from, 95, 155. 
Sieves, Use of, 19. 
Silioa-brioks, Sands for, 5, 38, 96. 
Silica, Estimation of, 15. 
Silicate of Soda, Sands for, 3 
Silica-ware, 130. 
Silt-grade, 9, 13, 12-4. 
Silurian Rooks, 144. 
Silver-sand, 3, 60. 
Silver Strand (Co. Wioklow), 77, 

144, 165. 
Sims, H., 61. 

Singer, F., On Use of Alumina, 98. 
Single-vessel Elutriator, 25. 
Size of Grains, 12. 
Skelmersdale (Lanes), 64. 
Sliohter, G. S., On Grading, 18, 28. 
Slieve More (Aohill Island), 96. 
Slime from washing Glass - Sands, 

120. 

Smart, G. W., 58. 
Smith, Dr. G. Otis, 134. 
Soaking Pits, Sands for, 5, 7. 
Soap-making Sands, 3, 
Society of Glass Technology, 33, 34, 

134. 

Soda-ash, 35. 
Soda-glass, 35. 
Sodium Carbonate for cleaning Sand, 

127. 
Sodium Carbonate, Use of in Elutri- 

ation, 22. 
Sodium Hydrosulphide for Bleaching 

Sands, 126. 

Sonstodt's Solution, 16. 
Sorting of Sands, 12. 
South Africa, Sands from, 153. 
Southampton, G9. 
South Cave (Yorkshire), 68, 98, 141, 

143, 156, 162. 
Spital (Cheshire), 45, 85, 99, 129, 

141, 142, 143, 154, 156, 162. 
Spreohsaol, 34. 
Spreohsaal Kalendar, 34, 85. 
Stadler, H., On Elutriation, 18, 21, 

23. 



Staffordshire, Freight to, from Mel^ 

don, 116. 
Staffordshire, Sands from, 5, 102, 

141, 144, 164. 
Stained-glass, 146. 
Statistics dealing with Sands, 150. 
Steenberg,N., On Danish Sands, 168. 
Staling (Denmark), 168. 
Stiperatones (Salop), 95, 99, 129, 

141, 155. 

Stirling, N.B., 89. 
Stoborough (Dorset), 73, 164. 
Stone, near Aylesbury, 51. 
Stone, Balph W., 134. 
Stonefield (Co. Mayo), 94. 
Stone Lone (Leighton Buzzard), 58. 
" Stones " in Glass, Cause of, 46. 
Stourbridge Fire-bricks, 38. 
Stourbridge, Glass-making at, 47 r 

145, 146. 

Strahan, Dr. A., 102. 
Sudbury (Suffolk), 159. 
Suffolk, Sands from, 13, 29, 159. 
Sunderland, Glass-making at, 146. 
Superfine Sand, 13, 45. 
Surrey, Sands from, 4, 49, 60, 61, 

141. 
Sussex, Sands from, 49, 52, 54, 61, 

141, 143. 
Sutherlandsliiro, Rocks from, 109, 

155, 160. 

Button (Co. Dublin), 77, 144, 165. 
Svendborg (Denmark), 168. 
" Sweating " of Mortar due to Sand, 

4. 

Sweden, Felspars from, 114. 
Sweden, Glass- Sands of, 149. 



Table-glass, 47, 48, 142, 145. 

Tables, 121, 125, 154-170. 

Taohylyte, 42. 

Tadmarton (Oxfordshire), 69, 162. 

Talargooh (Flintshire), 98, 164. 

Tammann, G., 33. 

Tank-furnaces, 38, 45, 145. 

Tank-washing, 64, 89. 

Tavern Rook Sand Co., St. Louis, 

138, 169, 170. . 
Technical Glass, 145. 
Temperature Effect on Elutriation, 

21. 
Tertiary Deposits, 9, 72, 73, 134, 

153, 156, 163, 168. 
Terrill, A. J., 71. 
ThanetBeds, 35, 45, 50, 73, 74, 117,. 

141, 142, 156, 159, 164. 
Thermometer-glass, 36, 42. 
Thorianite in Sands, 2. 
Thornton, J. & T., 88. 



182 



INDEX. 



Thorpe, T., 33. 

Thoulet's Solution, 16. 

Thuringian Forest-sand, 36, 42. 

Time-glasses, 4, 146. 

Tinahely (Go. Wicklow), 97, 145. 

Tiree, N.B., 165. 

Titanium-bearing Minerals, -13. 

Titanium in Sands, 15, 94. 

Topley, W., On Wealden Sands, 52, 

61. 

Torrington (Devon), 101, 157. 
Tramore (Waterford), 78, 106, 158. 
Transmission Capacity of Sand, 28.. 
Transport of Sands, 146, 149. 
Treatment of Sands and Eocks, 76, 

80, 119, 134, 148. 
Trelavour (Cornwall), 108, 160. 
Tresayes (Cornwall), 107, 160. 
Trevanaunce Cove (Cornwall), 101. 
Trevisoo (Cornwall), 108, 160. . 
Triassio Books, 45, 74, 84, 98, 103, 
' 104, 119, 120, 127, 141, 142, 143, 

154, 156, 162. 
Tridymite, 5. 
Tscheuschner, E., On Glass-Sands, 

.35. 
Tunbridge Wells Sands, 35, 52, 55, 

141, 142, 156, 162, 163. 
Turner and Sons, James, 74. 
Turner, Dr. W. E. S., 98. 
Tutbury, Glass-making at, 145, 146. 
Twelve Pins (Co. Galway), 155. 
Tyneside, Glass-making at, 146. 
Tyrone Co., Sand from, 91. fr'ee also 

Cookstown. 
Tyrsbaek (Denmark), 168. 



Uniformity Coefficient in Sands, 28. 
United States Geological Survey, 28, 

34, 46, 47, 118, 120, 184, 169. 
Unshin, Lough (Co. Donegal), 112. 
Upholland (Lanes), 64. 
Upper Estnarine Series, 65. 
Upper Glacial Deposits, 29. 
Upper Greensand, 117, 118, 142, 

159. 

Uses of Sands, 1. 
Utica (Illinois), 169. 

Variation in Glass-Sands, 47. 
Vegetable Matter associated with 

Sands, 5, 11, 75, 119. 
Vein-Quartz, 36, 96, 97, 128. 
Vejle Dal (Denmark), 168. 
Vejle Fjord (Denmark), 168. 
Velocities of Water and Air-currents 

for separating Sands, 20, 124. 
Venetifin Glass, 35. 



Victoria (Australia), Sand from, 139, 
153, 157, 165. 



Waen (Flintshire), 83. 

Wagon, S., 62. 

Walker, H. A., 85. 

Walsall, Glass-making at, 145. 

Wansford (Northants), 68, 143. 

Wareham (Dorset), 73. 

Warrington, 64, 145. 

Washing, Apparatus for, 57, 89, 122. 

Washing Bay, Coalisland, L. Neagh, 

77, 165. 
Washing- of Sands, 57, 58, 64, 89, 

119, 148. 
Washing-soda, Use of in Emtriation, 

22. 

Waterford Glass, 82, 145. 
Waterfoid, Eocks from, 78, 106, 

158. 

" Water-glass," Sands for, 3. 
Water-supply, Sands used for, 5. 
Wealden Deposits, 85, 52, 54, 55, 

140, 141, 142, 154, 156, 162. 
Wedgwood's Pottery, 160. 
Wedron Silica Co., Ottawa, Illinois, 

136, 169, 170. 

Weinsohenk on Petrographio me- 
thods, 17. 

Westerham (Kent), 61. 
Western Europe, Glass-sands of, 3.9, 

130-133, 144, 153, 166, 167. 
Westphalia, Sands from, 35. 
" Westport Silica," 80, 96, 128, 145, 

154. 155, 161. 
West Virginia, U.S.A., 137, 149, 169, 

170. 

Wetzel, C., 33. 

Werford, Sands from, 77, 165. 
Weybridge (Surrey), 73. 
White Castle (Londonderry), 92. 
Whiteoliff Bay (Isle of Wight), 72, 

73, 140, 141, 164. 
White Mine (Ballycastle), 90. 
White Book, Tinahely, 97. 
Wioklow, Felsite from, 106, 158. 
Wioklow Co., Sands from, 77, 97, 

165. 

Wild & Sons, William, 96. 
Wilson, Sir Spenoer Maryon, 73. 
Wiltshire, Sands from, 71, 142. 
Winohelsea (Sussex), 53. 
Windle, Sir Bertram, 77. 
Window-glass, 35, 36, 37, 49, 57, 64, 

140, 142, 146. 
Wisconsin, U.S.A., 149. 
Witchell, Prof. E. T. D., 129. 
Wood, W. Frank, 40. 
Workability of Sands, 148. 



INDEX. 



183 



Worksop (Notts), 45, 74, 76, 99, 141, 

14,2, 154, 162. 

Wotton (Ootteswolds), 32, 143. 
Wright, On Behaviour of Silica, 80. 
Wright, W. B., 111. 
Xonotime in Sands, 2. 



Yorkshire, Glass-making in, 52, 68, 

76, 82, 99, 146. 
Yorkshire, Glass-Sands from, 32, 45, 

49, 65, 67, 68, 82, 98, 99, 121, 140, 

141, 142, 143, 156, 162. 
Youghal, 78. 



Yeovil (Somerset), 45, 143. 
Ynyalas (Cardiganshire), 97, 164. 
York Glass-Works, 133, 167. 



Zsohimmer, B., 33. 
Zircon, 2, 10, 43. 




PRINTED BY TAYLOR AND PBANOIS, BED 1ION COUBT, FLBBT STREET.
Internet Archive Audio

Featured

Top

Images

Featured

Top

Software

Featured

Top

Books

Featured

Top

Video

Featured

Top

Mobile Apps

Browser Extensions

Archive-It Subscription

Save Page Now

Full text of "A Memoir on British Resources of Sands and Rocks Used in Glass Making"

See other formats
