Craske on the Medway Cement Industry

I was uncertain whether to transcribe this historical piece, since some stupid AI bot (or a human in the lower reaches of the IQ spectrum) is bound to cut-and-paste it into their thesis on cement industry history, without my de-bunking notes. As history, it is hair-raisingly inaccurate. However I have transcribed it because it has been quoted, as if true, by many subsequent writers, and it at least shows that disrespect for the truth is not an exclusively modern phenomenon. It appeared in the Chatham, Rochester & Brompton Observer, 7/9/1898, p 8.

The Cement Industry

Its rise and progress on the Medway

by W R Craske

The manufactures of a locality are largely determined by its natural resources, geographical position and facilities for distribution. With abundant stores of chalk and clay, its nearness to the largest distributing port in the world and its splendid water highway made it inevitable that this valley would become a centre of the cement trade.

The first discoverer

Over seventy years ago one John Aspdin (note 1) discovered that a combination of chalk and the blue clay found in the delta of the Medway (note 2), mixed in certain proportions and burnt to a clinker, and afterwards ground to a fine powder, possessed setting properties when mixed with water, and that if it were incorporated with other materials of a suitable nature a building material was produced that had the advantages of great strength, durability, and cheapness, and which would harden quickly under water as well as in the air. A small works was built on the Isle of Dogs (note 3), and the manufacture was carried on there for some years with varying success, for the engineers and contractors of those days were chary in using a material that was not uniform in its results, and which gave a large proportion of failures, some of which were serious and all of which were expensive and annoying. It was many years before Portland cement became generally known in the building trade, and many more before its value was fully recognised.

Early Works on the Medway

The late Mr J B White and Mr J C Johnston (note 4) may be credited with the development of the manufacture and an improvement of the quality that gained the confidence of users, and early in the fifties a few works were erected on the Thames and Medway. The late Mr Burge whose son is still connected with some of the Rochester works in conjunction with Mr Johnston about this time took the old oil mill at Frindsbury and converted it into the first cement works on the Medway (note 5). Their example was quickly followed by Messrs Lee at Halling, Hilton at Faversham and Upnor, Campbell at Wouldham, Hollick at Borstal, Larke at Strood, Weekes at Whorne’s Place, and one or two others, but the factories were all small and 30 years ago the total output on the Medway did not exceed 1000 to 1200 tons per week. During the next ten years there was but a very small addition to the quantity made, and the trade was not looked upon with favour by capitalists, as many mistakes had been made in the erection of the works then in operation, and a large amount of money had been sunk in experiments that had proved to be failures, but those who had money invested in it gradually profited by the experience of trial, and the knowledge gained induced more care to be exercised in the manufacture and greater reliability resulted. Engineers began to find that Portland cement could be made of such quality that it could be safely used for many purposes that had not hitherto been thought of and that it was the cheapest building material known where great resistances were required. This caused more interest to be taken in the trade by persons looking for safe investments, and the flood of commercial prosperity about 25 years ago caused a large influx of capital which was the means of erecting six or eight works on the Medway and the enlargement of almost all the old ones.

The Present Output

This was the position in 1875 when the trade may be considered to have firmly established itself as one of the most important on the river and when the wages distributed weekly by its agency became an important factor in the spending power of the working classes (note 6). Since that time new works have been built year by year, old works have been extended and at the present time the output is not much, if any, short of 15,000 tons per week This estimate is for the Medway only and does not include the large make on the Thames and Tyne and the many works in almost every part of Great Britain where suitable material and facilities are found.

Money Circulated

The statement that 15,000 tons of cement are made every week on the Medway, and that the direct wages paid in connection therewith is about £6,000 per week, gives but a very inadequate idea of the amount of money it puts into circulation. The carriage of this quantity from the works to the places where it is used, distributed, or transhipped for longer voyages gives constant employment to over 200 barges and fully another 100 can be added to this number that are employed in carrying to the works coal, coke, clay, and other materials used in the manufacture. These 300 barges earn a gross freight of about £2,000 per week, one moiety of which is paid to the crews as wages, and the other moiety is largely reduced by the amount that is paid by the owners for repairs, of which a large proportion goes for shipwrights’ wages. Add to this a further sum for the building of new barges, and it will be readily seen to what a large extent the barge building trade has profited by the growth of the cement industry (note 7).

The great wear and tear of machinery in cement works has called into existence several engineers’ shops employing a large number of men that are almost entirely dependent upon it for work, and the building and allied trades have received an impetus that is due to the same cause. If from some cause all the cement works were to be closed immediately, it may be fairly estimated that the working classes in Rochester and the neighbourhood would lose purchasing power to the extent of at least £10,000 per week. What this would mean to the tradesmen, property owners, and ratepayers generally it is impossible to overestimate (note 8).

Processes Old and New

During the first 40 years, the manufacture was carried on almost exclusively by what is known as the wet process. The chalk and clay are put into a wash mill, into which a stream of water flows, and they are reduced to a degree of fineness that will allow the mixture to pass through sieves of wire gauze, the holes of which are about one fortieth of an inch square. This mixture is technically called slurry, and flows into settling tanks, where it remains until it is of sufficient consistency to be taken on to the drying floors. These are buildings in which heat is generated by means of coke ovens, connected with an expanse of iron plates, under which the heat passes, and upon which the slurry remains until it is dry enough to be taken to the kilns. The kilns used in this system are those with high domes open at the top, and the waste heat and gases evolved in the burning pass upwards into the air. To burn the cement to a clinker the kilns are filled with alternate layers of coke and dry slurry; the mass is lighted at the bottom and allowed to burn itself out, which does not happen before all the coke is consumed. The last operation is the reduction of the clinker to a powder by grinding it in a mill, and the finished product is then ready for the consumer.

Although the manufacturer is still practically on the lines indicated in the foregoing paragraph, there have been many modifications introduced with a view to improve the quality and to reduce the cost of labour, fuel, wear and tear, &c. The first radical change was introduced by the late Mr Goreham, of Northfleet, who found that by mixing the raw materials with about one tenth of the quantity of water generally used, and passing the slurry through millstones to reduce the chalk to the requisite fineness, it could be pumped direct on to the drying floors and thus avoiding the use of settling backs. This effected a considerable saving in labour, and also enabled the manufacturer to turn the raw material into finished cement within fourteen days, the time previously occupied being from three to four months at least, and often longer. Closely following on Mr Goreham’s discovery was that of Mr J C Johnston. He closed the tops of the kilns, and built in place of the high domes long chambers into which the wet slurry was pumped to suitable depth, and through which the heat from the burning clinker in the kiln passed, and which was so regulated that enough slurry was dried each time of burning to reload the kiln, thus making the process continuous. By thus utilising the waste heat from the kilns the drying floors were not required, and the coal used in heating them was saved. Other kilns of the same type, especially those designed by Mr G Burge and Mr G Batchelor, have to a large extent superseded Mr Johnston’s, but the object of all has been the same, and the long chambers have been generally adhered to (note 9).

The Grinding Plant

No detail in the works has called forth as much inventive ingenuity as the grinding plant, and in no department has there been so much money wasted in fruitless experiments. In the old days all the grinding was done by French burr stones of a similar character to those used for grinding wheat but made of burrs especially selected for hardness and soundness. While engineers were satisfied with cement ground sufficiently fine for 80 per cent to pass through a sieve with 1,600 holes to the square inch, the need for other machinery was not felt, but in the course of time it was found that the finer the cement was ground, the greater was the strength of the mortar or concrete made with it, and it became necessary to erect mills that would do the work with less wear and tear, and taking less power to drive than burr stones. The number of mills that have been introduced, tried and generally thrown onto the scrap heap is legion. But those invented by our townsmen Mr J Collis and Mr P J Neate (note 10), and two or three that have had their origin in Germany, have proved successful and are rapidly superseding stones. At the present time engineers’ specifications for fineness vary from 90% through a sieve having 2,500 holes to the square inch to 95% through one with 5,600 holes, and in a few instances a still greater degree of fineness is demanded (note 11). The difference between the most coarsely ground cement of the present day and the best that was current a few years since will explain some of the difficulties that have had to be faced in the erection of suitable milling plant.

The Chemist at Work

Perhaps the principal cause of the rapid growth in the trade during the last few years is the greater care exercised in the manufacture and the consequent improvement in the quality. Twenty years ago there was not a works in England using chemical tests for the analysis of the raw material and slurry (note 12); now an elementary knowledge of chemistry is to be found in every testing room, and but very few makers fail in testing their slurry as it leaves the wash mill several times in the day. Our German competitors are largely responsible for this departure as they realised earlier than we the importance of making a really reliable article, and to overcome the difficulties in using very inferior raw materials they instituted such rigid chemical supervision in every department that they were soon able to compete with our superior chalk and clay on fairly equal terms (note 13).

What of the Workers? (note 14)

The establishment of large works in what had been for generations a purely agricultural district has naturally had a considerable effect upon the habits and character of the people. Much of their former simplicity and frugality has been lost; the younger men move about from place to place as new works are built, or a demand for labour arises, and a few years of contact with varying groups of their fellows develops in many a larger intellectual life than they would ever have known, had they remained, like their fathers, on the farms upon which they were born; in others the only result is a deeper depth of animalism.

The demand for houses in the villages has caused many to be built without due regard for the needs of the people, and instead of all being supplied with large gardens, they are too often huddled together, and present more the appearance of cotton villages in Lancashire or pottery towns in Staffordshire than of homes in rural Kent.

Against the evil must be placed the higher standard of living, and the greater facilities for improvement and recreation now enjoyed, and where thrift is a dominant feature in the character, opportunities offer for saving which did not exist under the old conditions of life.

It is impossible not to regret that the river has lost much of its sylvan beauty, but there are still reaches that gladden the eye, and the activity and life on it has added a charm it did not formerly possess.

Notes

Note 1. John Aspdin. And not a typo – he repeats it. He can’t even get Joseph Aspdin’s name right. This immediately establishes the limited extent of Craske’s historical knowledge.

Note 2. The idea that Aspdin invented Portland cement using Thames chalk and Medway clay is an “alternate fact” that would have been jeered at, even at the time. It is still encountered in careless accounts today. Several authors were already in print giving more authoritative accounts, including Reid, whose book had been out for 20 years, and had been read - one would have thought – by everybody in the industry. However, for a decrepit industry under threat from foreign competition, promotion of this lie supported the increasingly frantic proposition that only chalk and Medway mud could be used to make “real” Portland cement. Joseph Aspdin may have had access to ballast chalk at Wakefield, but, having never stirred from there, Medway mud was entirely foreign to him. And the Medway does not have a delta!

Note 3. Wouldn’t it be great if this were so? Of course, it is an absurd fantasy, maybe influenced by a tale of William Aspdin’s much later arrival at Rotherhithe, compounded with the fact that there were a few Roman cement plants on the Isle of Dogs.

Note 4. Again, he can’t even get I C Johnson’s name right. Johnson was still living, universally acknowledged as the “father of the industry”, and known to everybody, except, apparently, Craske.

Note 5. He means Portland cement works – there were several Roman cement plants in the area much earlier.

Note 6. Shortly after his arrival in Borstal around 1870, he was already chairman of the local Liberal party, belonging to the radical wing. His attitudes exactly convey the reasons for working class attraction to, and eventual rejection of, the Liberals.

Note 7. The excessive emphasis on sailing barge trade was one of the main reasons for the early demise of most of the Medway industry. Although a railway was projected as early as the 1850s, there was never a line on the west bank, dooming the plants on that side, including Craske’s at Borstal.

Note 8. This emphasis on importance to the local economy – if anything, augmented by the industry’s inefficiency and low productivity – ironically led a few years later to the Tariff Reform League’s use of Medway cement as a prime example of the need for protectionism. Joseph Chamberlain held a very well-publicised meeting at Martin Earles. Maybe it was influenced by this article.

Note 9. In 1898, the short-lived craze for continuous shaft kilns, most prevalent on the Medway, had yet to begin.

Note 10. Both Collis and Neate produced roller mills, which were particularly popular in the Medway area, although also used further afield. Their use died out during the following two decades.

Note 11. The “engineering standards” of the time used sieve analysis as their sole means of defining cement fineness (see article). This had a negative effect on innovation, since coarse sieves could not address the real source of cement performance – the quantity of ultra-fine material or “flour”. In particular, the local use of roller mills instead of flat stones allowed coarse material to be reduced easily – and cheaply – while failing to produce the necessary fines, leading to poor strength performance - another nail in the coffin of a backward industry.

Note 12. Craske’s knowledge was insufficient to make this broad generalisation, but it probably was not far off the mark. In fact, a contempt for chemistry was always – and remained - a characteristic of the British cement industry.

Note 13. Here Medway chauvinism underplays the vast superiority of German cements at the time.

Note 14. The owner of this website (whose working-class credentials are impeccable) dissociates himself entirely from what follows. But such language was common at the time, even among champagne Socialists. After all, G B Shaw said:

I hate the poor and look forward eagerly to their extermination.

And in the early 20th century Encyclopaedia Britannica, in the article on England, there’s this:

The old-established British stock, marked by dark hair, long head and moderate stature, appears better able than others to withstand crowding and factory conditions, provided that it gets a sufficient quantity of food, and the immigrants into industrial areas included large numbers of this type, while the fair, stalwart type has apparently been streaming off to the new lands pioneering, just as it came pioneering to Britain centuries ago.

By the latter, they presumably mean the Hunnish hoards who arrived in Britain in the 6th century, and yes – they did all go to Sithifricah. Presumably the Britannica was not meant for factory hands like me. Of course, such sentiments became less popular after 1945. But I digress . . . .