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purpose it is essential to have a good mould-store, so that the makers may return the moulds as soon as they are done with, for it is unreasonable to expect men to be responsible for moulds which have to lie about the works for want of a proper place in which to keep them. A little care on this point will soon repay itself, both in the increased life of the moulds and in the saving of time lost in hunting for a mould which has been out of use for a year or more but which is suddenly required. A catalogue of moulds in stock (preferably worked on the card index system) will be found of great service in this connection, and by keeping it strictly up to date' and weeding out all old and destroyed moulds, it may be made a valuable factor in the search for moulds which, in so many works at the present day, takes up so much time unnecessarily.

6

The use of dirty water, or water to which soda or other chemicals have been added, should be discouraged in the manufacture of plaster moulds, as it tends to lessen their durability, although sometimes increasing their initial hardness.

CHAPTER IV.

TRANSPORT, CONVEYORS, ETC.

UNDER this heading may be included the mechanism or appliances used for moving anything from one place to another. The principal requirements are: (1) rapid transit, (2) safe transit, and (3) small cost both in capital outlay and in maintenance charges. In regard to this last point, it is necessary to include all charges, whether direct or indirect, as otherwise it might be found that a method of transport which appeared to be cheap at first sight might, by its slowness or by its interfering with other parts of the works, actually cost more than another which had at first appeared more expensive.

Hand Labour and Barrows are the most elementary form of transport, but they should be used as little as possible, because they are, relatively, very expensive. There are many cases in which they cannot be avoided, but their advantages and disadvantages are so well known as to need no further mention here. Whenever the transportation of goods between two points is regular and in sufficient quantity, it will usually be found that some form of automatic conveyor will prove more economical in the long run, saving both time and goods. Where the distance is too great for this a tramway will prove satisfactory in most

cases.

Tramways are, in many respects, the most suitable means of transport for goods and material about the works, as they can be used in bad weather and under conditions when other appliances will fail to work. The original cost of construction is not excessive, and the cost of maintenance is small if the road is well looked after. If allowed to get into a bad state, tramways tend to cause great losses through broken goods and through excessive wear and tear of the waggons, as well as waste of power if the waggons are moved by rope haulage. If the waggons are to be moved by men it is not well for them to hold more than

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three-quarters of a cubic yard of material, and for most purposes rather less than this capacity is preferable, whilst for pony traction on a fairly level track about twice this capacity will be found convenient. If the waggons are unnecessarily small, time will be wasted, but if they are too large additional men will be required to assist, who, at the same time, do not need to exert much power and hence cause a waste of money.

If the track crosses the public road, it is desirable to have some form of brake attached to the waggon, or, if this is not thought advisable, the pony should be fitted into fixed shafts and not into the usual form of loose chain traces. In this way the pony, by backing, will be able to stop the waggon almost instantaneously, unless the track is very steep, whereas with the chain traces the momentum of the waggon may lead to a greater difficulty in drawing up suddenly if necessity arises. entirely on the works this precaution is not quite so necessary.

For tracks

As transport by waggon may easily form an expensive item in the cost of production, it is wise to keep a careful look-out on the average cost per waggon of the different kinds of material, and, in some cases, to pay by the waggon-load, or ton, rather than by time. This remark applies with equal force to horse haulage, but to a less extent when the transport is worked mechanically.

The requirements of a good waggon, tub, lorrie, bogey, or whatever other name these articles may be known by, in different parts of the country, are: (1) strength, (2) lightness, (3) stability, (4) compactness, (5) easy running. Ball-bearings are increasingly used in the construction of waggons, and it is, in any case, desirable to oil or grease the waggons at very frequent intervals if they are to run freely; (6) easy discharge. This is particularly important in the case of tipping-waggons.' Some of the more recent designs of waggon for clayworks are particularly convenient in this respect, and combine great natural stability with remarkable ease in emptying.

Waggons and tubs drawn by ropes and chains are referred to on page 103 (Haulage).

It is essential that the track for tramways should be well laid on soundly bedded sleepers to which the rails are securely fastened, preferably by means of bolts, which are cheaper in the long run than the more usual nails. Special care is needed in the case of points, particularly movable ones. In planning the tramway system of a works care should be taken to avoid inserting too many points, as these affect the smoothness of the running, and may consequently cause damage to clay articles in transit to the

kilns, etc., and also make it necessary for the waggon to run more slowly over the points in order to prevent it being derailed. Points are, however, to be preferred to turn-tables, and the latter should only be used when really necessary; it will often be found quicker to take the waggon several yards further and use points than to have a shorter distance and use a turn-table. Much will depend on circumstances, and in some cases turn-tables cannot be avoided. When used they should be kept in first-class condition so as to turn easily.

It is highly advisable that the maintenance of the rails and turn-tables should be in the charge of one man, who should also be compelled to keep all the tools, nails, bolts, etc., he requires for this work in a special box, which he should take with him to the places where repairs are needful. If this is done, and great care taken that the tools, etc., are not allowed to lie about on any pretext whatever, and the disused bolts, etc., carried right away to their proper place, many annoying incidents which result from iron getting access to the clay will be avoided, and much of the time wasted in fetching tools, etc., will be saved. These may appear to be little points truly, but they are none the less important.

If care is taken in arranging the working places of the different workmen, considerable sums of money may often be saved in the transport of clay to the makers. Thus in many yards it is easily possible to run the clay direct on to the maker's bench by a little arrangement, whereas at the present time it is all carried to one heap and is re-distributed from thence by means of barrows or other conveyances, thus involving a double handling. This clumsy plan may often be avoided by having a gangway some 8 feet above the floor of the making sheds for the waggons to run on. These waggons are preferably of the side-tipping pattern, as the rails need not then be broken to allow of emptying out the clay.

Road Traction, whether by horse and cart or by the more modern traction engine or motor van, is usually cheaper for local deliveries than the railway. The most convenient type of cart is an ordinary tip-cart of about 2 cubic yards capacity, but if the district is very hilly a somewhat smaller cart would probably be more convenient. With steam waggons much greater loads can be carried and over roads which would be almost impassable for a horse, but the roads must be sufficiently good to stand the weight. This is a difficulty in some districts where there is a considerable number of bridges. Quite apart from these heavier vehicles, however, there is a great field for the use of motors to replace the ordinary horse-drawn vehicles

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for cartage, especially in brickworks with a large local trade or situated some little distance from the railway. Except for motors of the light delivery-van type, it is necessary that the driver should be a skilled motor mechanic, capable of telling from the beat of his engine whether anything is the matter and of repairing it at once. This means higher wages than a horse-driver's, but the increased output of the motor as compared with that of a horse and cart will largely compensate for this. It is strongly to be recommended that all motors and traction engines in regular use should not be used more than five working days and should be thoroughly overhauled on the sixth. Including such repairs as re-boring cylinders, re-tubing boiler, and other more extensive repairs, it is not safe to reckon on more than 240 working days per year.

It is almost impossible at the present time to institute a really reliable comparison of working costs and standing charges of the different forms of traction available, as so much depends on local conditions. The question of depreciation also complicates the problem. It is probably correct to write off a quarter of the cost at the end of the first year's working, and each succeeding year to take off one quarter of what is left; thus a motor engine costing £800 would depreciate to £600 at the end of one year, to £450 at the end of two years, to £190 at the end of five years, and after eight years' use it would have on the books a value only one-tenth of its original cost. This method of calculating depreciation is much safer and fairer all round than the more usual one of writing off 10 per cent. of the original cost each year. In estimating the cost of motors and engines with a view to comparing different types in actual use, errors of considerable magnitude often creep in owing to the careless way in which repairs are not charged to the transport, but to a general account for the whole works.

As regards the size and type of motor, it may be taken roughly that loads under 5 tons are most economically carried on the motor itself, but larger loads are best distributed between the motor and a trailer. The relative advantage of oil (petrol, etc.) over steam are most marked in the smaller loads-10 tons and under-and consist chiefly in economy of power production per ton-mile, in the rapidity of starting, and the smaller cost of attendance. For larger engines the cost of spirit is too great for economy, but if an engine burning heavy oil could be constructed, the adoption of a heavier type of motor waggon would make great progress.

In consequence of the expense of repairs, many firms now sublet