Table I. Weight, Absorption, And Hardness Of Various Bricks

No. Description of Brick.

Locality Where Mads.

DlMENSIONS.

Dry Weight.

Absorption of Water Per Cent

Of Dry Weight in

Degree Of Hardness.

1 Brick.

Per Cub Ft.

l Sec.

1 Min.

30 Min.

1 Day

1 Wk.

1

Wire-cut Metallin ...............

Buckley, near Chester, .......

Inches .

Lbs. Ozs .

Lbs.

_

•38

•38

•77

1 16

9

8.9 x 4.2 x 2.5

18 0

148.5

2

Pressed " .............

"

8.6 x 4. 1 x 2.4

7 7

151.8

42

•42

•84

1.26

1.26

9

3

Vitrifield Plain Paving .....

Heathfield, Newton Abbot,

91 x 4.4x20

6 12

143.8

-

-

-

1.38

1.85

8.5

4

Blue Facing ........

Ruabon, N. Wales,.....

8.8x4.2x2.9

8 9

136

•36

•36

•36

1.46

2.54

8.5

5

Red ,...............

"

88 x 42 x 30

8 13$

137.8

•35

1.06

2.12

5.31

8

6

Best White Glazed,..........

Heathfield, Newton Abbot,

8.8 x 4.3 x 2.8

7 9|

123.8

•41

•82

2.88

5.76

617

8.5

7

Brook Hill Blue,............

Bucknell, Berks, Chester........

9.1 x 4.3 x 2.5

7 4

128

1.72

517

6.03

6.90

8.18

7.5

8

Flintshire White ...............

"

9.0x4.3x 2.6

7 4

124.5

2.15

6.46

8.62

1034

10.34

7

9

Bed handmade Facing (No. 12),..

Bracknell, Berks,......

8.9 x 4.1 x 2.5

6 4.

118.9

•49

2.94

10.94

12.93

12.93

3

10

Machine-made wire-cut Red Facing (No. 13x),...............

"

9.0x4.3x2.6

6 9.

113.6

•47

1.89

9.47

13.74

13.74

3

11

Hand-made pressed Red Facing (No. 4),................

" "

8.8 x 4.3 x 2.5

5 15.

109

2.09

7 84

1361

1413

1413

2

12

Red,....................

Dunton Green, near Sevenoaks, ..................

9.1x4.3x2.5

6 4

110.4

1.00

400

13.50

15.00

15.00

3.5

13

Red Rubber (No. 9),.........

Bracknell, Berks,......

9.8 x 4.9 x3.1

9 3

106.6

2.04

6.80

13 94

15.30

15.30

1.5

14

White Gault,..............

Dunton Green, nearSevenoaks, .................

9.0 x 4.3 x 2.5

6 4

111.6

1.50

6.50

18.00

20.00

20.50

7

A description of the raw materials, and of the processes of brick-making; would be out of place here, but it is necessary to point out that bricks may be handmade or machine-made, the latter being now most common. Machine-mado bricks are of two kinds, wire-cut and pressed. In making the former, the clay is forced through a die a little larger than the bed-measurements of the finished bricks, - that is to say, about 9 inches by 4 inches, - and after leaving the die, is cut into slices about 3 inches thick; wire-cut bricks are therefore without indentations or "frogs". Pressed bricks are each submitted to pressure in a machine before being burnt, and have usually frogs on one or both beds, and often also the name or initials of the maker impressed on them. Pressed bricks, as a rule, are more dense and impervious, and have smoother faces and truer anises; they are therefore almost invariably used for good external work. The frogs afford a key for the mortar, but are the cause of kiln-cracks in the bricks, and lessen their ultimate strength.

Facing-bricks may be obtained of various colours, - white, buff, numerous shades of red, and blue-black, - the colour alone being no guide to the real quality of the brick.

Cutters or rubbers are somewhat soft and absorbent bricks, of a yellow or red colour, prepared from materials of an extreme degree of fineness, and used for panels, arches, splays, and other positions, where the bricks must be carved, or cut and rubbed to shape. They are now being largely superseded by bricks which have been moulded to the desired shape before being burnt, and by terracotta, as these are as a rule much more durable, and at the same time - if a considerable number of pieces of one pattern are required - cheaper.

of ordinary facing-bricks there are so many varieties, and these so constantly changing, that only a cursory glance can be attempted.

Good white bricks arc made from the gault clay in Kent and Bedford, while some of the best are burnt from the china-clay deposited in pockets among the Devonshire hills. They may also be obtained from several other counties.

The red bricks made at Ruabon in Denbighshire are among the best in the country. The Leicestershire and Hampshire pressed bricks also enjoy a good reputation. In all these counties moulded bricks for plinths, sills, string-courses, jambs, and many other purposes are made. Other red pressed facing-bricks of good quality are manufactured at Peterborough, and in Berkshire, Staffordshire, Lancashire. Yorkshire, and other counties.

Staffordshire is the centre of the blue-brick industry, the best bricks being produced in the southern part of the county. The peculiar colour is due to the large quantity of iron in the clay. The bricks are not all blue to the core; usually the middle of the brick is red, shading gradually into the blue, but, whatever the colour, the material should be vitrified throughout. The best Staffordshire bricks are known as "best pressed"; wire-cut bricks are often called "seconds", and are cheaper, and not so dense and true.

Much inferior stuff is now sold as Staffordshire ware, - stuff made of coarse gritty materials, artificially coloured, and warped and cracked in every direction. Quite recently I had to condemn a number of such bricks which had been brought to a building for heavy foundation work; some of the bricks were so badly cracked that one could see right through them.

Good Staffordshire blue bricks are extremely hard, heavy, impervious, and durable, suitable for all situations where great weights have to be carried and damp to be resisted; hence their value for foundations and basement-\valls, and for engineering works. Their colour renders them objectionable for the facing of houses above the level of the plinth or base-course.

The best bricks for external facings in towns are undoubtedly "best" salt-glazed bricks, those made in the neighbourhood of Leeds and Halifax being of excellent quality.

Salt-glazed bricks are of two kinds, namely, common salt-glazed (known also as "seconds"), which are merely ordinary pressed bricks fused on the surface by common salt being thrown into the kiln, and best salt-glazed, the faces of which are dipped into a "slip" of the finest sifted clay before being fired and salted. Bricks of the former kind are chiefly used for sewers, manholes, and other places, where a clean impervious surface is required at a comparatively little cost. The "best" bricks, however, are used for external facings, and for internal walls, dadoes, urinals, etc. They are hard, durable, true in shape, and free from surface-cracks, and, being vitrified on the face, they are clean, easily washed, and practically non-absorbent. As the "slip" is of the same clay as the brick itself, the whole is fused into one mass in the kiln, and the glaze cannot shell off as it sometimes does from " enamelled" bricks.

An artistic advantage in favour of salt-glazed bricks consists in their rich and varying colour, which imparts a character and movement to a wall very different from the dull monotony of ordinary (or indeed of enamelled) brickwork. An exceedingly picturesque example of their use - by what architect I do not know - may be seen in Great George Street, London. They have also been used in the plinth of the Clerkenwell town-hall. There can be no doubt that they will be more frequently adopted in years to come.

Enamelled bricks are good pressed bricks which, after being fired once, are dipped several times into "slips" and then into a glaze before being burnt a second time. In the "wet-dip" process the preliminary firing is omitted. They are really bricks to the face of which a porcelain plate (or, in inferior bricks, an earthenware plate) is fused. They are not greatly to be commended for external use as the glaze may fly under stress of weather, but of their advantages for internal work there can be no question. In water-closets, urinals, lavatories, bath-rooms, sculleries, corridors, basements, areas, and other places where dirt and darkness are wont to abide, enamelled bricks may be used with vast improvement of "sweetness and light". They may also be adopted in larders, pantries, and kitchens, and even in dust-bins and the inspection-chambers of drains. The "best" bricks of the best makers are now of such excellent quality that little fear of "shelling" or decay need be entertained.