The local industries of Glasgow and West of Scotland.

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Published in 1901. The following are the brick references contained within.

 

Bricks are largely made from the laminated clay beds of the raised 
beaches and of interglacial position, as also from the boulder clay, which 
is cleared of stones for that purpose. The fire clay beds of the coal 
measures and millstone grit series afford good material for the manu- 
facture of fire bricks, gas retorts, and other furnace fittings, as well 
as various kinds of enamel ware, while the red marls of the Calciferous 
Sandstone period, and the more highly ferruginous of the post-glacial 
clays, are used for the production of bright red bricks, tiles, pipes — 
the so-called terra-cotta. 

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Coltness (Coltness Iron Co.). Newmains Station, C.B. — This works 
was commenced in 1837 by Messrs. Houldsworth. It originally con- 
sisted of twelve furnaces, but the number has now been reduced to 
nine, which are of modern type, and larger than the old furnaces. Attached 
to the furnaces is a foundry for the casting of moulds for the steel works 
direct from the blast furnaces^ and there are also a steel furnace, 
briquette plant, and brick works. 

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The method of distilling the bituminous shale was revolutionised 
in 1881-82 by the introduction of the Young and Beilby retort, which 
was designed for the purpose of subjecting the spent shale of the oil- 
making retort to a further treatment with steam at a higher temperature 
than that suitable for oil making ; the primary object of this improvement
was to convert the nitrogen left in the spent shale into ammonia. 
In the Toung and Beilby retort the upper half is made of iron, and the 
lower half of fire-brick ; at the top of the retort is a hopper containing 
shale, which is heated by the hot gases passing np from the retort 
below. As the whole column of material in the retort is moved down 
by the removal of a part of the spent ash at the bottom, the shale 
passes in succession through the iron retort and the fire-brick oven. 
In the former it is exposed to a low red heat, and parts with its hydro- 
carbon oils and paraffin; in the latter, where it is heated to bright 
redness and exposed to the action of steam, the carbon is more or less 
completely burned away in steam, producing water gas and ammonia. 
The retorts are placed in chambers of fire-brick, and are heated by 
producer gas, which is burned along with the uncondensible gas in narrow 
flues around the retorts. In order to facilitate the removal of the spent 
ash, and thus to minimise the danger arising from fusion of the ash at the 
high temperature of the brick chamber, the retort is provided with an easily 
accessible curved mouthpiece and door at the bottom. This system of 
distilling the shale at two different temperatures has the effect of greatly 
increasing the yield of ammonia and of the valuable paraffin scale as well, 
as can be seen from the following figures : — 
                                            1882 Retort          1897 Young and Beilby Retort
Burning oil from 1 ton of shale,            12.6 gallons              12.9 gallons
Lubricating oil        "                    5.4 gallons               5.4 gallons
Paraffin scale         "                    3.3 gallons               4.3 gallons
Ammonium sulphate      "                    12 lbs                    36 lbs

These retorts were very generally adopted, and the system of distil- 
ling the shale at two different temperatures has been applied in all the 
more recent retorts which have been designed as improvements upon 
the original Yoimg and Beilby type. The chief changes in the newest 
forms of shale retorts, apart from structural details, are an increase 
in the capacity, so that the shale remains a longer time in the retort, 
and the adoption of various mechanical devices for the removal of the 
spent shale ash; the main results of these improvements are a great 
reduction in the cost of retorting, and an increased yield of crude oil 
and ammonia. 

In the chemistry of refining the crude oil there has been little or 
no change. Sulphuric acid is used to remove basic tars and resinous 
substances, and caustic soda solution for the removal of creosote tars 
and sulphur compounds; the different oils are separated by fractional 
distillation, and the paraffin by cooling, crystallisation, and filtration. The 
quality of the lubricating oil has been improved by distilling the heavy 
oils off caustic soda, by the plentiful use of superheated steam in the dis- 
tillations, and by the adoption of improved freezing machines and filter 
processes. A great advance in the distillation process was made when 
N. M. Henderson designed his apparatus for continuous distillation. In 
this system the stills are arranged in series, and the oil flows from charg- 
ing tanks through each still in succession, undergoing fractionation in its 
course. The most volatile fractions are distilled off from the first still 
and the least volatile from the last. The use of this process has resulted 
in considerable economy in labour, fuel, maintenance, and chemicals 
and the loss in refining has been materially reduced.

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FIRE BRICK AND FIRE CLAY. 

Extensive deposits of fire clay exist in Lanarkshire. These were worked 
to a small extent in making very moderate quantities of fire brick until 
well on in the early part of last century, when the extensive fields in the 
neighbourhood of Garnkirk and Glenboig were discovered. The fire clay is 
got here at no great depth, and the seams are specially thick. It is in these 
districts that the trade has had its greatest development. Prom very 
small beginnings the making of fire bricks grew alongside the iron and 
steel trades, and latterly has become the great industry which makes it 
so prominent a feature in the West of Scotland. 

The fire clays in the neighbourhood of Glasgow are situated geologi- 
cally in the upper coal series and limestone series. They are found 
at all depths, from the surface open-cast workings to pits 40 or 50 
fathoms. The workable seams vary in thickness from about 3 feet 
to 30 or 40 feet. The process of fire brick making is pretty much the 
same all over the West of Scotland. For precision, we will briefly follow the 
process as applied at the Glenboig works. The clay is there found 113 feet 
deep, and varies in thickness from 6 to 9 feet. In descending the shaft, we 
pass through from 12 to 20 feet of floating whinstone, which covers a con- 
siderable part of the Glenboig district; under this are numerous beds of 
fire clay and siliceous rocks, some of them almost pure silica. The system of 
mining is what is called stoop-and-room. The workings are 12 feet wide, 
and the stoops left in are 30 feet square, excepting at the pit bottom, where 
they are much larger. The stoops may be cut through, and when the proper 
time comes removed altogether. The clay in its natural state is very hard, 
and requires to be blown down with gunpowder. The average daily output
of each man is from 4 to 5 tons, according tathe thickness or the hardness of 
the clay. The clay is sent out in pieces about the size of ordinary coal. 
It is raised to a high pithead platform, whence it is run either to the 
crushing mill direct or to the bing, where it is exposed to the action of the 
weather. 

In bricks for general furnace purposes a close texture is not required. 
The brick must have sufficient flour in it to give it toughness and strength 
so that it may bear the rough shunting of our railways, and the care- 
less treatment which fire bricks too often receive in shipping and 
trans-shipping. But when that is accomplished, they are made as 
rough and open in the grain as possible, that they may be the better 
able to resist high and variable temperatures. 

The crushing and milling are effected by means of revolving pans, in 
which heavy iron-edge rollers run. The clay is first broken with hammers, 
and shovelled into the crushing mill, the bottom of which has perforations 
through which the clay is crushed. Scrapers attached to the pan beneath 
throw it into an iron box, whence it is lifted by means of an endless 
chain fitted with elevator buckets, and delivered into a cylindrical riddle 
8 feet long and 2 feet in diameter. This is so placed that the riddled clay 
drops to a second set of elevators, while the pieces too large to pass through 
X drop back into the crushing mill. The second set of elevators has two duties 
to perform — it either sends the fine-ground fire clay, which is used as mortar 
in furnace building, to an endless belt, which carries it to the waggons on the 
railway outside, or the rougher brick clay to the tempering pans by means 
of a box 60 feet long placed overhead. In this box there is a travelling 
chain fitted with clots, by means of which the clay is dragged along. In the 
bottom of the box are holes to which conductors are attached, one to each 
mill. These, from their position, are always kept full, and when the mill- 
man requires clay he has only to draw a sluice at the lower end of the 
conductor and the clay drops into the pan. He then turns on the water, 
and the mill is charged in a second or two. For mortar clay, a fine riddle 
is used, and for brick clay one of larger mesh. In preparing clay for 
glass house blocks, gas retorts, Bessemer tuyeres, and all large articles, a 
proportion of previously burnt bricks or clay is added, to prevent cracking 
in the drying and burning. Dry mills are generally employed for temper- 
ing when the clay is of a soft aluminous nature, but they are not suitable for 
hard, gritty, siliceous clays. When ready for moulding, the clay is dis- 
charged into small tipping bogeys, which are raised by means of a 
steam hoist to the upper floor of the drying store. It is 
there run along a little railway, whence it is dropped down through 
suitable openings to the moulders' benches. By this method one man 
delivers the clay to nine or ten moulders. It has also the advantage 
of taking the trafl&c off the drying floor. Once in the moulders' hands, 
the clay is rapidly turned into bricks. A good workman, with his 
carrier, will make 2500 bricks a day. Solid brass moulds are used 
for regular sizes, but for the larger sizes wooden moulds are employed. 
Iron, zinc, and glass have been tried, but hard brass has many advantages. 
The moulds are made one-twelfth larger than the size of the burnt brick, to 
allow for shrinkage. The face board on which the brick is made is covered 
with thick " plaiding," and the trade mark is fixed upon it, so that making 
and stamping are performed in one operation. No machine has yet been 
made capable of taking well-milled fire clay as it leaves the pans, turning it 
rapidly into bricks, and delivering them, square and sharp-edged, on the 
pallet-boards. When the brick is moulded by hand, the monlder discharges 
it on to a pallet board ; the carrier then places another board on the top of 
it, and between the two the soft brick is carried with safety and deposited 
on edge on the stove floor, where it remains till it is hard and ready for 
the kiln. The defects most common in fire brick (with the exception of soft 
burning) are produced in the stove, and it is here alone that soundness and 
£nish can be given to them. If the stove floor is uneven, the shape of the 
brick is spoiled, and if too much heat is applied the bricks are warped and 
cracked. Some clays are very liable to crack when too quickly dried, and 
where stoves are badly constructed this occasions loss and injures the 
quality of the brick to a serious extent. Bricks of this description give 
also increased breakage in the kiln and, indeed, in every stage of their 
existence. To meet all this, a patented construction of stove is employed at 
Glenboig. The stoves are 120 feet in length by 36 feet wide, and are fired 
from one end. The drying floors are entirely formed with cast-iron plates, 
each 4 feet by 2 feet by | of an inch. These are smooth and easily heated. 
Underneath the iron floor there is another, formed of fire-clay slabs, about 
3 inches thick, which run from the furnace end to the middle of the stove, a 
distance of 60 feet. The fires and hot flues are underneath the fire-clay 
slabs, and between the fire-clay slabs and the iron plates forming the upper 
floor there is an air space 8 inches deep. This communicates with the 
outer air at the gable over the fires. Each flue has its own air space. By 
this means the stove may be fired up so as to heat effectually the back end, 
while too much heat in the furnace end is prevented by the current of cold 
air passing between the two floors. The air so admitted joins the lower flue 
at the middle of the stove, carrying with it the superfluoi^ heat at the 
furnace end, and utilising it where it is required. Each stove of the 
dimensions named turns out 24,000 bricks a day. Every brick is ready for 
the kiln the day after it is moulded. By this system of drying the cost is 
lessened, while the production for a given space is nearly doubled and the 
quality much improved. Various methods have been tried, such as exhaust 
steam in pipes or flues, and hot air in a variety of ways. The method just 
described gives steady night and day drying, as it is not dependent on 
the boiler being off or on, and is in every respect to be preferred, 
particularly where large production and perfect regularity are required. 
When dry, the bricks are wheeled to the kilns. The firing is done very 
gently at first. This is continued for two days, till the damp is com- 
pletely steamed out of them. The kiln is then put on full fire, which 
is kept up for about two days, during which a bright white heat is 
steadily arrived at, this being maintained till the sink in the bricks 
has taken place, when the firing ceases and the kiln gradually cools
The making of a fire brick is like the making of a pin — the article looks 
a simple one, yet the process is complex and somewhat elaborate. In no 
process is close and continued attention more essential if the best results 
are to be obtained. As in scientific investigation, the smallest gleam of 
truth has its value and its place, so in the workshop every ascertained 
fact has its value also, and if it gets its place it will bring its reward 
in the general result. 

A brick rich in silica, yet containing a fair proportion of alumina, and 
comparatively free from alkalis and other impurities, is the one which 
combines in the highest degree infusibility and freedom from splitting, and 
is consequently found to be best suited for the greatest number of the most
important furnace purposes, such as puddling, rolling mill and forge 
furnaces, gas retorts, etc., where the great desideratum is the combination of 
these qualities. The following is the analysis of a Glenboig brick by Sir 
Frederick Abel, F.B.S., taken from the stock as used at the Boyal Arsenal, 
Woolwich ; — 



Silica, 62.50 

Aluminium, 34.00 

Iron per oxide, 2.70 

Alkalis loss, etc., 0.80


Two clays might be found giving a similar analysis which would yet 
produce very different fire bricks. In this very analysis we have a case in 
point. The silica and alumina are largely combined as a silicate of alumina, 
and this is much to be preferred to a clay possessing the same proportions 
of these substances but not chemically combined. 

It is not surprising, therefore, that these bricks are extensively used 
at home, and that their use has spread to England, gradually over 
Europe, and latterly, it may be said, to almost every part of the globe. 
Wherever they have gone they have made for themselves a reputation and a 
market which grows from year to year. 

Many other articles are made from this fire clay, notably gas 
retorts made in one piece, and also blocks for built gas retorts. 
Sewage pipes are also made in great quantities and of all dimen- 
sions, and as sewage works are now being constructed in many lands these 
pipes are being regularly shipped to many foreign countries. Attention 
is also given to the requirements for special furnaces, such as glass- 
works, where large blocks of varying size and shape are required. The 
manufacture of bricks with a white glazed surface is another branch 
of the trade which is rapidly developing here. These are being 
increasingly used for facing walls in back courts, xmderground railway 
stations, etc. Several makers are giving special attention to the 
development of this branch. 

It is interesting to know that in this connection several of the fire 
clay makers in the West of Scotland are working at sanitary ware, not only 
at articles of a coarse description, such as sinks, troughs, urinals for 
railway stations, etc., but also at what may be considered as the better 
articles, such as water-closet pans, wash-hand basins, etc. This branch 
is alreaidy of considerable dimensions, and, like the other branches, it is 
expanding with rapid strides. Chimney cans in greatly varying shapes and 
sizes, roof ridges, copings of walls, bottoms for sewers, vases, and other 
ornamental articles for use in gardens, the forms of some of which are 
admittedly fine, and claim to have artistic merit, are likewise made. There 
are other things which all show how this manufacture — starting with 
fire bricks, which still are its backbone — is spreading out to most varied 
productions. 

One or two of the makers show vases and other ornamental articles 
for garden use, and the forms of some of them are undoubtedly good and 
artistic. 

This brief reference — ^which is far from being exhaustive — ^to the 
varied nature of the fire-clay trade gives some idea of its great develop- 
ment. The manufacture stands out as one of the most growing 
industries of the district, and is carried on with great enterprise. 
Skill is displayed in the metHods and processes of manufacture, and 
the business is pushed with energy in every part of the world. 

Before concluding, reference must be made to a patent kiln invented 
by Mr. Dunnachie, the well-known managing director of the largest 
fire-clay works in the district. It is known as the regenerative gas 
kiln or oven. Whilst its main feature is the use of gas as the heating 
agent, it is also to some extent of the nature of a continuous kiln or 
oven — the heat from the kiln directly fired being carried into the 
next, while the air for combustion is passed through the one that had 
previously been fired, thus coming into contact with the gas at a 
high temperature. It has been in use for a good many years, and its 
success has long been established in this country and elsewhere, 
notably in America. It not only does the work well by producing 
thoroughly burnt bricks, but is far more economical than the ordinary 
method of burning fire bricks. 

At least one firm gives special attention to what are known as 
adamantine bricks, etc. These are exceptionally hard. They are used 
for the paving of railway stations, stables, etc., and are of special 
value for the foundation of tall chimneys and other erections, as 
they are able to bear almost any pressure from the superincumbent 
material. The trade employs quite an army of workmen, and its 
production is enormous, the quantities sent out from Glasgow being a 
feature in the shipping trade of the city. Moreover, it is a trade which 
seems to have no bounds to its rapid growth, which has now continued for so 
many years.
COMMON BUILDING BRICKS. 

Around Glasgow there exist extensive beds of good clay for brick 
making. In many instances these are not exhausted by the brick 
maker before the builder comes on the scene and drives him off. But 
the brick maker only moves further afield, and on fresh ground 
resumes his operations, so that now, in almost every direction around 
the city, the familiar brickfield is to be seen. Owing to the abund- 
ance of stone in the West of Scotland, bricks have been little used in 
the erection of dwellings, except in the building of partitions and, to a 
greater extent, of gables and back walls. They are, however, extensively 
used in the erection of workshops and factories of every kind. The 
clay, being well adapted for the purpose, makes excellent bricks, and 
factories are constructed in which practically no stone whatever is used, 
the bricks, when well burned, being exceptionally strong and solid. 
There are somewhere approaching forty millions of these bricks made 
in the neighbourhood of Glasgow annually, and the great bulk of these 
is used in the city and neighbourhood. There are fully one 
thousand men employed. These bricks are largely used in the 
erection of factory chimneys; indeed all such chimneys are built 
with this material in this quarter, and carefully burnt bricks 
are excellently adapted for the purpose, being well able to carry any 
weight that may be placed upon them. Formerly these common bricks 
were all made by hand, and as they were dried outside, brick making only 
continued during the summer months, the clay being prepared during the 
winter. But years ago some makers turned their attention to the possi- 
bility of making bricks by the aid of machinery, and ultimately with entire 
success. The machinery then adopted is still in use in this district, and is 
said to have been the forerunner of all such machines. These machines, 
combined with the adoption of drying sheds heated by steam and the use 
of the pug mill for preparing the clay, enables brick making to go steadily 
on throughout the whole year. As the city extends, there is also a natural 
increase in the number of bricks used. 

Some ten years ago the interesting discovery was made that the great 
heaps of blaise which accumulate around ironstone pit banks, and which 
so frequently formed part of the landscape aroimd Glasgow, could be turned 
into building bricks at very moderate expense, as a certain portion of 
this material was partly combustible, and aided in the burning of the bricks. 
This material not being plastic, the process of making differs from that used 
for bricks made of clay. It is crushed into a powder, then it is placed in 
moulds, and the brick is formed under very considerable pressure. These 
bricks are burned in kilns constructed after the Hoffman plan. In exposed 
situations bricks of clay are preferable, as it is thought they better resist 
the action of the weather ; but these blaise bricks are used chiefly for 
inside partitions, gable walls, etc., and other places where there is no 
excessive pressure or exposure, and as they are cheap they are used some- 
what extensively. Both of these branches of brick making have fully 
participated in the prosperity which has been enjoyed for several years in the 
building trade of the district. 

        
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