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Watering places, sanitary condition of, 550 White lead, manufacture of. 223

Wood paving for Paris thoroughfares, 614
Watford, Medical Officer of Health, report,

poisoning, 65, 142

Woollams & Co.'s exhibits at Sanitary Institute
412

Whyte & Bradford's exhibits at Glaszov, 218 Exhibition, 205
rural, Sanitary Inspector's report of, Wigton sewerage works, 375

non-arsenical wall papers, 510
81

Willesden, the patent roc-proof paper, 316 Woollen clothing, Dr. Jaeger's, 414
urban,

Williams, Dr. Dawson, on insanitary dwell. Worcestershire sauce and cholera, 163
326

ings in Whitechapel, 243

Workmen's dwellings at Mulhausen, 307
Watts' patent asphyxiator, 316
Williams' sewer gas trap, 82

in Plymouth, 2;8
Wedgwood & Son's tiles, 345.
Willington Quay, insanitary state of dwellings

improved in Leeds, 469
Wellington (Somerset), Medical Officer of

at, 523

Worksop. Local Board and Urban Sanitary
Health, report of, 33

Williton rural (Western Divi-ion), Medical Authority, 95.
Wellington's water-closet, 84

Officer's report, 325

Workshops in Birmingham, sanitary condition
Wells, pollution of, 447

Willoughby, Dr. E. F., on baths and bathing,
Wells, Sir T. Spencer, on

cremation or
434

Wright & Co., awards to, 165
burial, 609

on the sewerage of Frankfort,

Dr., on Southport, 171
Welwyn rural, Sanitary Inspector's report of,

Wright's exhibits at Glasgow, 216
326
Window.gardening, society for promoting, 40

flush cisterns, 36
Wentworth's exhibits at Glasgow, 221

Windsor, Medical Officer's repori, 89
Weobley rural, Sanitary Inspector's report of,

outcasts, 374
35

Winlaton sewage scheme, 434
Wery' (the) atmospheric cowl, 277

Winter, Mr. F. B., on lodzing-houses for the
West Cowes water supply, 524

poor as an investment, 296

Yorkshire Association of Medical Officers of
West's, A. J. & C., gas heating exhibits, 514 Withers (the) patent gas engine. 558

! Health, 139
West Kent combined district, 23

Withington urban, Medical Officer's Report, Young, Mr. J., on the scavenging of towns,
What is a pauper? 449

136

190 : discussion, 198
Wheeler's exhibits at Glasgow, 221
Woking, water supply of, 143

Young's patent for creating sewage, 36
Where to take a holiday (Holiday number of Wolstanton and Burslem rural, Medical
the LONDON MEDICAL RECORD), rov, 91

Ofñcers' report, 136
Whitechapel, insanitary dwellings in, 243 Wolverhampton Corporation and sewage farms,
swimming bath at, 589

312
Whitehall, sanitary statistics at, 594

Sanitary Protection Association, Zenith (the) air or steam screw-propeller, 316
White lead factori:s on the Tyne, 231

457

Zymotic diseases, 361

251

“THE WEEKLY EXHIBITION RECORD.'
THE WEEKLY EXHIBITION RECORD-a temporary weekly supplement of the SANITARY RECORD-
contains full accounts, profusely illustrated, of the exhibits in the Health Division of the International
Health Exhibition, and the principal papers read at the Sanitary Conferences organised by the Society
of Medical Officers of Health, the Sanitary Institute of Great Britain, the Parkes Museum of Hygiene,
the Social Science Association, and the National Health Society. The EXHIBITION RECORD is at
present being published weekly, price 2d. to Non-subscribers, free to Subscribers. The first Number
was published on May 7, and will be continued till the work of description has been adequately carried
out. Publishers : Smith, Elder, & Co., 15 Waterloo Place, London, S.W.

British Plumbing Company in the present Exhibition, ORIGINAL PAPERS.

Before coating cast iron, care should be taken that

the surfaces are thoroughly free from sand and other ON THE USE OF CAST IRON FOR

foreign substances. A steel wire brush, circular,

and provided with a long handle, is useful for scourHOUSE DRAINS.*

ing out the interior of pipes, and they may afterwards

be wiped out with an oily cloth. I have here two By W. D. Scott MONCRIEFF, C.E.

specimens of Dr. Angus Smith's composition kindly The materials used for the construction of house

lent me by Mr. Rawlinson. One of them has lain drains are practically limited to bricks, earthenware, the composition does not seem originally to have

in the ground for twenty-eight years, and though and cast iron. The advantages of cast iron are 1; been very well applied to begin with, the iron its superior strength and capacity to resist fracture; 2, the greater lengths in which it can be manufac- is still in an excellent state of preservation. The tured, and the corresponding reduction in the num

other specimen shows the application of the prober of joints ; 3, the greater facilities for making the tecting medium in the greatest perfection, and the

test of its condition as regards consistency and temjoints secure by means of lead, sulphur, oxidised iron filings, &c.

perature is to be found in the high glazing or varnish

which is given to the surface of the iron when it is The points to be considered in adopting cast iron

properly applied. The Bower-Barff process has are a, the available means for preserving it; b, the determination of the capacity and weight of the recently been brought prominently into public notice.

It consists of coating the surfaces of the iron to be pipes ; 6, the character of the connections best suited to the material ; d, the nature of the joints; exhibit of some specimens of pipes treated in this

preserved with magnetic oxide. There is also an e, the comparative cost. The experience of gas and water companies, in any particular neighbour

way. They were coated at St. Neots, Huntingdon

shire, under the direction of Mr. Bower, to whom hood, ought to be a guide as to the life of a

my thanks are due for having done so for the purcast-iron drain pipe in regard to corrosion from

pose of this exhibition. I have no doubt of the the outside inwards. When there is no oxide of iron in the soil through which they are laid, the destruc.

efficacy of this plan when the surfaces of the iron to

be dealt with are so exposed as to be capable of tion of the pipes from exterior rusting is so slow as to justify their use without any special means of pro

thorough cleansing. The interior of cast-iron pipes

require special care in this respect. The cores' tection. In the case of drain pipes there is no rea

from which they are made being of 'green sand' son to exclude a good protecting medium because it is poisonous, an objection which of course holds

leave rough particles behind them which at the high good in the case of pipes used for the distribution of temperature required for the production of the drinking water. In addition to the ordinary kinds magnetic oxide must be apt, I think, to form a of paint made from preparations of lead, &c., there

vitreous glazing unless the pipes are very carefully

cleansed beforehand. are two methods of preserving pipes from oxidation which deserve more than a passing notice. One of have adopted for ordinary house drains is 5 inches,

To return to the pipes themselves the diameter I these consists in coating with a preparation of tar known as Dr. Angus Smith's composition, and the by the engineers of the London Sanitary Protection

This is the same as has been recently recommended other I refer to is known as the Bower-Barff process, in which the surfaces are covered with magnetic especially when the drain is flushed by means of a

Association. In cases of considerable fall, more oxide produced at a high temperature in a furnace Mushing tank, a velocity of Aow is obtained which built for the purpose. În a letter with which Dr. Angus Smith 'favoured me a few days ago, he men

would be apt to tell severely upon the joints of tioned a temperature of 400° Fahr. as the most suit- earthenware pipes laid in cement, and considering able for the application of his preparation. A

the great sanitary importance of the rapid movecertain amount of practice is required in dealing Ducie's house in Portman Square, the sanitary

ment this is a point in favour of cast iron. In Lord with it in order to insure the proper consistency of the material when cooled. If it has been subjected by the North British Plumbing Company under

arrangements of which have recently been altered for some time to the necessary temperature, evapo- the direction of the Association just spoken of, ration makes the residual mixture hard and brittle after cooling. To avoid this a barrel of oil must be diameter and 99 feet in length, with a fall of i in

there is a direct line of cast-iron drain pipe, 5 inches kept at hand to mix with the composition, so as to keep it in its original proportions. If too much oil

33. The end nearest the street sewer is provided is added the coating will not be hard enough. I

with a Kemyon air chamber floor and manhole. At have arranged an apparatus consisting of a trough

the other extremity of the length of 99 feet there is heated by means of gas jets for applying the mix

a similar provision for inspection but upon a smaller ture, but it is better, I believe, to have the pipes cast-iron drain-pipe, about 70 feet in length, passes

scale ; beyond this point a further stretch of 5-inch dipped vertically. The use of steam in a doublelined chamber appears to me would be an advan

on to the back of the premises and is provided with tageous method of working it if the temperature of

an 80-gallon flush tank. It is found that the velocity 300° Fahr. recommended in the printed circulars is along the length of 99 feet first spoken of, is at the

of flow between the two disconnecting chambers sufficient. In that case a steam boiler would need to be provided, capable of standing a working pressure ning nearly full bore this condition of things senders

rate of 5 feet per second. As the drain pipe is runof 75 lbs. to the square inch. There are several specimens of the composition shown by the North

it impossible that any obstruction in the shape of sewage matter can remain behind. The elements

essential to the creation of sewer gas being wanting Read at the National Health Society's Exhibition, June 5, 1883. t ! 400 ° F. is necessary the boiler would require to be able to

its absence from the drain is practically guaranteed. stand a working pressure of 250 lbs.

The after part of the flush, in this case, always runs

B

Bore

16*1

22'1

319

40-6

clear.* I do not think much is to be gained by At the further or house end of the drain, instead of making the pipes less than 5" in. diameter and, on building a shallow manhole a cast-iron terminal is the other hand, a greater capacity is certainly not provided which is easily accessible and made secure required for the purposes of an ordinary household. by means of a similar plug to the one in the front I therefore look upon it as a useful dimension for just spoken of. In making a connection between a ordinary cases.

lead soil pipe and an iron socket, it is well to have a As there is an absence of hydraulic pressure in strong copper piece with a brazed lap seam slipped cast-iron pipes used for the conveyance of ordinary over the lead pipe and securely soldered to it. house-drainage, no extra thickness of metal is re- This allows for an oakum and red lead joint to be quired on that account, and they may therefore be made with sufficient substance to admit of caulking: made thinner than ordinary street mains. The As regards the comparative cost of iron and following is a table of the thickness and weight of earthenware for house drains, it must be borne in pipes of different diameters suitable for the purpose. mind that a great proportion of the total expense of

lifting an old drain and laying a new one is common Thickness of Metal.

to both systems. For instance the cost of excavaInches

ting, filling in, and making good is practically identi

cal. The time occupied in making good the joints 3"

of an earthenware drain is as six to one as compared 28.3 Ibs. per foot.

to an iron drain, the number of joints being as three 1998

269 34'4 23'4

to one in the case of 2 feet lengths of stoneware, and

6 feet lengths of iron, and I consider the time occuIn practice, I believe, pipes 5-16ths of an inch in pied in each as two to one in favour of the metal. thickness are sufficient for drainage purposes, and This nearly balances the extra cost of the matethis would give about 100 lbs. as the weight of a 6 ft. rial. The connections, including the air chamber length of pipe, 5 in. diameter.

floor, are more costly than earthenware, but this, in Among the various kinds of joints that known as the case of an ordinary London house drain should the.socket joint' appears to me to be the best not amount to more than 51. in all. I think that the suited for iron house drains, and although the pipes greater security to be obtained from the use of cast themselves may be made lighter than main pipes, iron quite justifies the expenditure of the additional the socket should not be reduced in weight or cost, and this will hold good so long as cast iron is strength because they are subjected to the same to be obtained at its present price. strain from the staving of the lead. Great care I shall now say a few words about the other kinds should be used in this respect, the more so as works of materials used for house drains, omitting bricks as men may be employed who are not so experienced obsolete. The practical objections to the use of as those in the service of water companies.

earthenware pipes are, ist, their liability to twist in A joint has been brought under my notice which firing. (Mr. Ernest Turner, in his excellent book has been patented by Mr. Eaton, C.E. It is in- 'Hints to Househunters,' speaks of having rejected tended for the use of Spence's metal or sulphur, and as many as 60 per cent. of pipes 'sent from wellconsists of an eccentric ring with a pouring hole on known manufacturers') ; 2nd, their liability to fracits top side. This overlaps the joint on both ends, ture. Concussion, without fracture of the surface, is and would be useful I think where it was required often sufficient to detach a branch piece from a pipe in to insert a length of pipe between two already in which the material seems to be continuous, although position, as this could be done without the necessityof the connection is often secured by little or nothing lifting more than the piece which was to be removed. but the glazing. As such a contingency may delay

The North British Plumbing Company have a squad of workmen for several hours until another carried out work upon the plan shown at the pipe and branch has been obtained, there is a tempNational Health Society's Exhibition under my tation to make use of defective pipes. Experience direction for Mr. Wills, M.P., in his house at shows that workmen are not above yielding to the Hyde Park Gardens. The cast-iron air chamber temptation of concealment. Broken bends and bad floor which was exhibited is an effort to simplify the connections are frequently found in places which arrangement now so frequently adopted with ad- are most available for the passage of sewer gas into vantage of having a manhole with a floor composed a dwelling. 3rd. The short lengths in which earthenof half pipes as a channel for the passage of the ware pipes are made necessitate an excessive numsewage and a trap beyond it to cut off the drain ber of joints in order to make up the length of an from the main sewer. In the cast-iron substitute ordinary house drain. The joints when made with for this appliance the mouth of the trap is practically clay are inefficient, and when made with cement are extended so as to form a floor for the manhole in subject to many drawbacks which nothing but great itself, and this extension has the advantage of and uncommon pains on the part of the workmen affording a provision for side inlets for the passage can overcome. The projection of cement to the of surface water and for other purposes. At the interior of the joint is a necessary condition, and this same time provision is made for a cleansing eye must be removed. In doing so the pipe is liable to towards the sewer which is fitted with a brass plug. movement during the critical period when the

cement is setting. The position of a pipe at the # The formulas which are commonly used for calculating the velocity of water in pipes running full must be considerably modified

bottom of a deep cutting renders it difficult to pack for the flow of house-drainage in 5-inch pipes. Taking

the joint from the bottom. Only a small proportion V=140 V75-u3rs

of earthenware house drains are found to be tight inclination, the rate of flow in the case of Lord Ducie's house drain, head of water. These are among the considerations in which r is the hydraulic mean depth in feet, and s the line of the when tested with a pressure of even a few inches already spoken of, in which the length approximately was 99 feet and the fall 3 feet, the velocity should have been at the rate of 6*22 feet which have led me to adopt iron in preference to per second. The difference between this and 5 feet is what is due to other materials, and I shall be glad if this paper has the pipe not running full, and further allowance must be made for the character of the discharge.

the effect of calling further attention to the subject.

a

BUILDING MATERIALS.

they have been re-used in later work. St. Alban's

Abbey, which was built in the latter part of the BY JOHN SLATER, B.A.

eleventh century, is a good example, a very large Fellow of the Royal Institute of British Architects.

number of bricks used in its construction having

been taken from the ruins of the old Roman city of II.-BRICKS AND MORTAR.

Verulam. The art of making bricks in England The geological nature of a country always deter- seems to have languished if not to have died out mines the character of its buildings. Where good altogether from the time of the departure of the natural building stone is abundant it is sure to be Romans until towards the end of the thirteenth cenquarried and used, but where this does not exist tury; the oldest existing example of brickwork being recourse is had to some artificial material which will Little Wenham Hall in Suffolk, which was built take its place. The material which has been more about 1260. In the time of Henry VIII. brickextensively used than any other is brick, the manu- making had considerably developed, and very elabofacture of which dates from the most remote anti- rate mouldings were executed which were probably quity of which we have any record.

copied from some of the specimens of brick archiHerodotus relates that the walls of Babylon were tecture which are to be met with in many parts of constructed of this material, and there are numerous the low countries. The seventeenth and eighteenth very interesting pictorial representations of brick- centuries afford many excellent examples of moulded making and brick-laying in the hieroglyphic litera-brickwork, and the number of bricks made in this ture of ancient Egypt which has been preserved to country kept on increasing until the manufacture us in stone blocks and mural tablets. Moreover, the received a temporary check at the end of the last existing ruins of some of the most ancient monu- century by the imposition of a tax, which varied at ments of Egypt have enabled modern explorers to times from 2s. 6d. to 5s. iod. per thousand until it obtain specimens of bricks which must be several was entirely repealed in 1850. Since that date the thousand years old, the great care taken in their manufacture has developed very largely in consemanufacture and the extreme dryness of the climate quence of the great increase in building operations, having tended to preserve them. For instance, and the number now made annually in this country there is at Memphis a pyramid still partially stand- cannot fall far short of ten thousand millions. ing built entirely of brick, and it is very probable The subject of bricks and brick-making is a very that this was erected by Asychis, who succeeded the wide one, and it would be obviously impossible to son of Cheops, the builder of the Great Pyramid. It is treat it fully in a short article. The number of probable that burnt bricks, such as were used in this different kinds of bricks is so large, the processes of pyramid, were the exception, and that Egyptian manufacture vary so widely in different parts of the bricks were for the most part sun-dried only, nearly country, and the scientific principles underlying all the common dwellings being constructed of this these processes—involving, as they do, a wide knowmaterial, but burnt bricks were occasionally used. ledge of physical science-are so complicated and

In Assyria, also, sun-dried bricks were very largely so little understood that several volumes might easily used, the huge mounds upon which the palaces were be written on the subject. I shall merely attempt erected being thus built, and the walls of the palaces to describe briefly what are the qualities of a good themselves having a brick backing faced with ala- brick, and upon what these qualities depend, and to baster. But the recent researches of M. Botta and point out the sanitary evils which result from the M. Victor Place have resulted in the discovery of use of such bricks as are too frequently employed some admirable examples of Assyrian brickwork of in the erection of those suburban villa residences burnt bricks, the most interesting being the arched which are the mushroom growths of the happy gateway of the entrance to the palace of Khorsabad, hunting-grounds of the speculating builder. which, both in materials and execution, would do no A brick is not an ultimate fact of nature, but its discredit to the best modern builder. The archivolt qualities as a building material depend upon the of this gateway is formed of wedge-shaped burnt constituents of the earth from which it is made and bricks, which are enamelled in six different colours. the manner in which this earth is prepared, dried,

Vitruvius mentions three kinds of bricks as having and burnt. It is frequently imagined that a brick is been used by the Greeks, called didoron, tetradoron, simply a rectangular piece of burnt clay ; but the and pentadoron; these differed only in size, and varieties of clays are very numerous, and, as a were more like tiles than our bricks. The two latter matter of fact, it is extremely rare to find natural kinds were square on plan, and Vitruvius says earths suitable for brick-making : nearly all require that those called tetradoron were used for private the admixture of sand, loam, chalk, or other subbuildings, the others for public. Roman bricks dif- stances. fered considerably in size : they were frequently Brick-earths may be divided into three classes, square, and in thickness rarely exceeded an inch and clays, marls, and loams. These all contain silica and three quarters : the clay was evidently well tem- alumina, and generally a trace of oxide of iron. pered, and the bricks thoroughly burnt, the surfaces Among the natural earths suitable for bricks is being in many cases scored deeply in order to form that mild alluvial clay or marl which used to be a key for the mortar. The Romans carried the art found near London combined with a calcareous of brickmaking to very great perfection, and used substance called “race.' This clay produced the this material for nearly all their principal buildings, fine yellow malms which give a special character to employing it as a backing to their walls even where London brickwork of the early part of the century. more costly materials were used for facing. They The marls have a considerable portion of lime introduced brickmaking into the various countries mixed with them, and the loams are light, sandy which they conquered where suitable earth was clays with an excess of silica : firebrick clays are found, among others into England, and frequent re- almost entirely free from lime, magnesia, &c. All mains of Roman brickwork still exist : in fact so these constituents are chemically combined, and it good were their bricks, that in numerous instances is a curious fact that it has hitherto been found im

а

possible to mix artificially the component parts in quite rotten, and falls to pieces at a single blow. the same proportions in which they exist naturally, This kind of brick is called a shuff, and if it iš atand to obtain that quality of plasticity which is in tempted to use such in a building damage is sure to the natural substance.

result. During the drying process the bricks have Pure clays are nearly always too strong for brick- to be protected from frost and wet. The next operamaking, and require to be mixed with milder earth, tion is burning, and London bricks such as have just and the loams are so sandy that the admixture of been described, in which the breeze is mixed with lime is required in order to bind together the the earth, are always burnt in a clamp. A clamp is siliceous particles.

an erection formed mainly of the raw bricks to be As the natural marls became exhausted, some burnt, cased in and partially supported by burnt one—it is not known who-discovered the possibility bricks. The raw bricks are placed in layers slightly of making an artificial marl or malm by mixing inclined towards an upright wall in the centre of the chalk and clay together, after thoroughly washing clamp, and between each layer of bricks is one of them and reducing them to pulp, much in the same breeze or cinders, the latter being thicker at the way as in the preliminary process of making Port- bottom of the clamp than at the top. Open flues land cement; and this process is now very largely are left at intervals which are filled with faggots for adopted for the best bricks in the neighbourhood of the purpose of firing the clamp, and after these have London. The general routine of brickmaking is as been ignited and the breeze is well alight the openings follows :—The ordinary brick-earth is dug in the of the flues are stopped up with clay, and the whole autumn, and turned over so that it may be broken up mass burns until the breeze is all consumed. The by the frosts of winter. It is then laid on a hard courses of brick are laid on the incline, and not floor, and malmed' in the spring ; that is, the horizontally, in order that as the breeze burns away liquid artificial malm, made as above stated, is con- there may be no tendency for the bricks to fall outducted on to the earth and covers it completely. wards. It is manifest that in this method of burning The proportion of malm to brick-earth depends it is quite impossible that all the bricks should be entirely upon the nature of the earth. The whole equally burnt, those near the cutside being undermass is left to settle for some weeks, and it is then burnt, and those close to the flues, where the draught

soiled '--that is, covered with fine sifted ashes ; is greatest, being frequently completely fused. The and this operation is a very important one, as upon former are called place bricks, and should never be the proportion of ashes to the whole bulk of earth used for outside work, or in situations where they are the quality of the brick when burnt will mainly de- subject to great pressure, which they are not calcupend. No general rule can, however, be laid down, lated to resist : the fused bricks are called burrs or as very much depends upon the nature of the ma- clinkers, and are extremely hard ; they may safely terial itself, also upon its state of humidity and be used for foundations, if not too irregular in shape, upon the meteorological conditions of the atmo- but are of course not suitable for facings. Between sphere at the time of mixing. A very large amount the two extremes of place bricks and clinkers there of actual experience is required, and it frequently are many gradations in the bricks from the same happens that the individual who has this experience clamp, and they are sorted out and sold as malms, is unable to impart it to others.* After soiling, the seconds, &c. It is frequently imagined that the heap is again left undisturbed till the moulding season variations in the quality of bricks when burnt are commences, when it is tempered—that is, turned owing to differences in the making, but in nine cases over with a spade and watered to bring it to a proper out of ten these are due solely to the burning. consistency, after which it is thrown into the pug In the provinces generally the processes of digging mill and thoroughly kneaded together when it is and turning over the brick earth are carried on ready for moulding, in which process a small quantity much in the same way as in the London brick-fields, of sand is mixed with it, and it is formed by hand but in many cases the earth is very hard, and coninto the size and shape of an ordinary brick. Now tains lumps of limestone, and here the process of all these processes, which have been briefly de- grinding and crushing the earth is resorted to. This scribed, have to be conducted with great care. The is an excellent practice so long as ordinary care is clay is hardly ever found without pebbles, and if used in the selection of the earth, but just as is found means are not adopted for screening them off or to be the case when a mortar mill is used for crushing them they will become imbedded in the grinding and mixing mortar, there is a strong tempbrick, and will cause it to crack during burning ; if tation to use almost any earth, whether suitable or the chalk is not thoroughly ground up, unslacked not, and the consequence is that bricks are frequently nodules will find their way into the bricks and will turned out that are quite worthless. For the best eventually slack and blow the brick to pieces ; if the class of bricks the earth is passed through the washtempering in the pug mill is not well done the brick ing mill, but for ordinary kinds the tempering is done will not be homogeneous ; and if the moulder does by treading and by the spade, as in the London disnot press the clay well and uniformly into the mould trict, but no breeze or fuel is mixed with the earth, it will when burnt lack density, and probably be very and this constitutes the principal difference between porous. Equal care has to be given to the next the stock brick and other kinds. The tempered process, which is that of drying the bricks in hacks earth is moulded and dried in the usual way, and the before burning, and it is this stage that probably is bricks are then burnt, or rather baked, in a kiln or most neglected. A considerable proportion of the oven, which is in some districts rectangular in shape contained water must be evaporated before it is safe and in others circular, with a domed top. Arched to burn the brick, and if this is not done it turns out fire-holes are formed opposite each other and con

nected by flues formed of the bricks which are to be A similar peculiarity has been noticed in the case of men who are accustomed to mix colours for dying purposes, the proper pro

baked : the number of the fire openings depends portion of the various tints being very important; and often the best upon the size of the kiln, which varies considerably. mixers use no measures at all, but are able to tell by a species of

The arrangement of the bricks in the kiln is a work instinct the amount that is required to bring about the desired result,

of some skill, as care must be taken that the heat

a

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