Chapter XIX: Lead and Its Compounds (4)

File cutting by hand is properly regarded as a dangerous industry. Although it claims annually large numbers as the victims of plumbism, it is difficult to say exactly in what form lead enters the system. In Sheffield the work is for the most part carried on in small, badly-ventilated, and overcrowded shops, more like outhouses, often situated in backyards or in the rear of dwellings, and not unfrequently contiguous to privies. Of 546 hand file cutting shops, in only 48 was there any means of ventilation provided, and in many of these “the means of ventilation consisted of a brick taken out of the wall.” Inside, the floor in nearly all of them is the bare earth, or bricks badly placed together. The workers are closely packed together without any consideration of the cubic space of the workroom. Hand file cutters as a class are anything but cleanly. Possibly their sense of indifference to dirt is largely the outcome of the long custom of the men taking their meals in shops totally unprovided with washing appliances. As a consequence of hammering and brushing the files, a considerable amount of dust is created, some of which must be inhaled, as the man or woman--for both sexes follow the occupation--bends closely over the stock. In several samples of dust removed from the stocks and rafters of the shops, lead[66] was found, the other constituents of the dust being particles of iron, charcoal, and chalk. File cutting is a sedentary occupation. In order to get as much light as possible upon their work, the men sit close up to the window, but they object to any part of the window being open on account of the cold and draughts. Owing to the close and dusty atmosphere in which the work is carried on, the general health of the file cutter becomes gradually undermined. As a consequence of this diminished vital resistance, and the practice of eating his food with unwashed hands, the licking of his fingers when at work, and inhalation of dust, the file cutter, in course of time, becomes the victim of lead poisoning. It is metallic lead dust that is given off during the blows with the hammer and chisel upon the file. Lead in this form is certainly much less harmful than when in such a soluble combination as the oxide or carbonate, but oxidation of the surface of the lead is constantly taking place, thereby rendering the metal more or less absorbable.

In addition to the ill-health caused by lead, pulmonary consumption carries off a large number of file cutters. The men work in a stooping position in overcrowded and ill-ventilated shops for long hours daily, with the result that the trade occupies an unenviable position on account of its mortality from phthisis. It is not, therefore, lead _quâ_ lead that is the sole danger, but the unhealthy conditions under which the labour is carried on.

In Sheffield, file cutting has received considerable attention from members of the medical profession. Thirty years ago Dr J. C. Hall denounced the trade as unhealthy, and demonstrated how, with such simple means as the free use of soap and water, much of the suffering and ill-health traceable to lead could be averted. Drs Sinclair White, Porter, and Harvey Littlejohn have in recent times written upon the evils of the trade from different standpoints. Notwithstanding all the attention the subject has received, hand file cutting still remains a most unhealthy industry. All the workers look anæmic. Many whom I examined both in Sheffield and in Rainhill had suffered from colic; several were completely disabled on account of paralysis of the extensor muscles of the fingers and wrists. It is rather in the chronic forms of plumbism, and in those persons in whom the kidneys become affected and health breaks down, that the worst effects of file cutting as an occupation are seen. Out of 100 file cutters examined by Dr Sinclair White, 74 had a blue line on the gums, 28 had had lead colic, and 20 paralysis of the wrists and fingers. The trade is characterised by a high mortality, the figures being 316 against 123 for occupied males in general.

The possibility of finding a substitute for the lead bed upon which the file is cut is, although not a new subject, one to which the Dangerous Trades Committee gave considerable attention. It was felt that if lead could be eliminated, the occupation would be rendered much less harmful. It was ascertained that in Germany pads of paper had been tried for small files, also that clay and sand encased in canvas, bars of wood, copper, vulcanite, and various combinations of indiarubber and gutta-percha had been tried, but each in turn discarded, owing to its unsuitability as a bed. This is a field of inquiry that would well repay any practical file cutter.

File cutters may work at their trade for years without becoming ill. Others again early suffer from colic, and the attacks of abdominal pain keep recurring every few months. Gradually, or suddenly, in those who have been thus afflicted, or even in those who have not had colic, paralysis of the fingers and hands develops. The peculiarity of file makers’ paralysis is, that while the extensor muscles of the fingers and wrists may become affected, so as to constitute a veritable “wrist-drop,” there is observed more frequently paralysis with wasting of the smaller muscles of the fingers and thumb. The loss of power is usually confined to the fingers of the left hand. It is with the left forefinger and thumb that the chisel is grasped, and as a consequence of the workman holding the chisel in this position during a great portion of the day, there is an amount of muscular strain experienced which cannot but play a part in determining the paralysis and its location. It is not the sole explanation, however, for the paralysis also affects at times the muscles of the right hand of the file cutter. This is the hammer hand that really does the hardest work, though not of the same strained character.

While it is to the fact of the work being conducted upon a lead bed, and the want of personal cleanliness on the part of the file cutter, that plumbism is mainly due, there are, as seen in Sheffield, contributory causes in operation which tend to increase the harmfulness of the occupation. One of these is, that file cutting is often a home industry. The work is frequently carried on in the living room or kitchen of a dwelling-house. Domestic and family duties come to be disregarded by the mother, for she, no less than the other members of the family, interruptedly lends a hand to increase the income of the home. Readers of this paper are prepared to learn that work under these circumstances is usually carried on in houses of the poorest description, and that, as a consequence of the dangerous character of the occupation, the unhealthy atmosphere of the workroom, and the constitution of the workers having become undermined through poverty, lead poisoning when it occurs is not only extremely severe, but may affect those who are simply living in the house and not actually engaged in file cutting at all. How to grapple satisfactorily with this most unhealthy trade is one of the many difficult labour problems that have been presented to the Home Office. Both for it and the peculiar tenement conditions under which the industry is carried on in Sheffield, fresh legislation is required.

In file cutting shops generally, the air space ought to be extended to 450 cubic feet at least for each person (it is 600 feet in cotton factories); there should be greater distance between the stocks, say 4 feet; better ventilation; washing appliances, with plenty of soap, water, towels, nail-brushes; wearing of overalls; periodic lime-washing of the workshops; concrete, asphalt, or wooden floors, which can be damped and swept regularly; prohibition of the taking of food into the workshops; and in the event of new buildings being erected, submission of the plans to the Home Office. For ventilation purposes Dr John Robertson recommends an inlet of the type of a Sherringham valve.

The report on the sickness experience of the Society of File Cutters by Hand in Sheffield, by Mr Stuart Uttley, Secretary of the Federated Trades Council, and which is published in the Fourth Interim Report of the Dangerous Trades Committee, 1899, p. 21, shows the extent to which file cutters are thrown off work every year through illness, including lead poisoning. This Society does not contribute any sick benefit, but during the illness of members their contributions to the Society cease. In this way it is readily known how many members are off work. The report deals with adult males only, and the dates chosen are 1891 and 1896, two years when trade was good, when all the members were at work, and malingering was practically beyond question. Out of 1092 members in the Society in 1891, the claims for exemption on account of sickness were equivalent to 1109 weeks, or a fraction of over one week per man per year. It is not maintained that all the sickness was due to plumbism. In 1896, 961 file cutters who were working in Sheffield claimed 951 weeks’ exemption from payment of contributions on account of sickness, or a fraction under one week each per man per year. There were 36 cases of plumbism in file cutters notified in Sheffield from July 1898 to June 1899, and of these 35 were men. A glance at Dr Tatham’s tables of comparative mortality, in an earlier part of this book, will show to what a large extent pulmonary consumption prevails in file cutters.

Dr Harvey Littlejohn found that in twelve years there occurred 91 deaths from plumbism in Sheffield, and that of the 91 people who died, 56 were file cutters. These statistics, however, do not represent the total number of deaths from lead poisoning. Plumbism is sometimes so tardily developed, and the constitution of the workman so gradually undermined, that as pathological changes are very slowly induced in internal organs, such as the kidneys, an individual may die long after he has given up working in lead, and the death be registered as having been caused by chronic disease of the kidneys, which but for lead poisoning would probably not have developed at all. It is thus that many fatal cases of lead poisoning fail to be attributed to their proper cause, owing to the fact that as death is the result of well-defined disease of internal organs, the connection of which with plumbism is overlooked, the occupation of the patient is either not inquired into or is completely ignored by the medical attendant. It was with the view of minimising this error, and of bringing into greater prominence the connection of lead poisoning with industrial occupation, that the Dangerous Trades Committee suggested in its final Report, 1899, p. 6, that if all deaths among workpeople who had been employed at any time within three months immediately preceding death in a trade in which Special Rules are established were compulsorily reported to the coroner, many facts of intrinsic and statistical value would be ascertained, and much light shed upon some of the occupations that give rise to industrial disease. By this means much injury and suffering might be mitigated at an earlier date than at present through alteration of the conditions under which the particular industry is carried on. Possibly six months would be better than the three suggested in the above sentence. Usually lead poisoning is so slowly and insidiously developed in file cutters, that the workpeople become indifferent to the dangers, and yet when symptoms of plumbism occur they can be very severe. Occasionally in female file cutters the malady shows itself at an early date after exposure, and the symptoms are those rather of the acute than the chronic form of plumbism.

Since, doubtless, the tendency to plumbism in file cutters is favoured by the nasty habit indulged in of licking their left thumb in order to get a better grip of the chisel, the application of resin to the finger has been recommended, but the suggestion does not appear to have met with much approval. Allusion has been made at the commencement of this article to the fact that it is only hand made file cutters who suffer from lead poisoning. In the United States all file cutting is done by machinery, and in that country plumbism among file cutters is unknown. In Britain machine-made files are slowly supplanting those cut by hand, but the customs of a trade die hard.

_Use of Lead in Potteries._

Staffordshire is the home of the pottery industry in this country. In Stoke-on-Trent, Burslem, Hanley, Longton, Fenton, and Tunstall, the trade is centred. These towns form what is called the “Potteries,” a district of about ten miles in length and four in breadth. Here nine-tenths of the earthenware produced in the United Kingdom are manufactured. The location of the manufacture of pottery in Staffordshire is an illustration of how industries cling to particular districts. At the present time none of the clay which is used in the manufacture of the finer earthenware is found in the neighbourhood. Originally there was plenty of coarse clay, and there is still abundance of marl, which is used for making saggers and firebricks. Coal, however, is abundant, and cheap fuel is an important item in the manufacture of pottery. In the early part of the seventeenth century there was a good supply of clay and fuel in the locality. The ware produced at that time was made from yellow or red marl, glazed with galena, or crushed raw lead ore brought from the Derbyshire mines; but in 1680, common salt was substituted for galena in the glaze. The articles produced were known as Crouch ware. It was in Burslem that this ware was first made. In 1759, Wedgwood perfected the white cream ware, and introduced many improvements into pottery, especially in the manufacture of green, black Egyptian, and jasper wares. Although England never outrivalled France and Germany, _e.g._ Sèvres or Dresden, in the manufacture of soft china, yet she has produced earthenware on a larger scale and supplied more of the world’s markets than other pottery districts, and is still doing her utmost to maintain her supremacy. In Staffordshire there is plenty of common clay, marl, or fireclay which, as already mentioned, is useful for making saggers, _i.e._ the large vessels in which earthenware is fired. The clays necessary for making the finer earthenware and china are brought from Dorset, Devon, and Cornwall. The clay or felspar used is, roughly speaking, a silicate of alumina in combination with water, potass, soda, lime, or iron. These ingredients act as fluxes on the silicate, and therefore help its vitrification. For earthenware, two kinds of clay may be used, the blue or ball clay and kaolin, but for porcelain only kaolin. It is estimated that upwards of 70,000 tons of ball clay are annually imported into the Potteries from the south of England. Kaolin, the Chinese word for the clay out of which porcelain is made, is in Staffordshire called China or Cornish clay, and is got from granite rocks. Workmen mix this Cornish clay with water in a large tank. The quartz, mica, and undissolved felspar sink to the bottom, while the thick white water in which the fine particles of kaolin are suspended is run off into another tank in which the kaolin is allowed to become precipitated. The precipitate is subsequently removed, dried, and exported from the south of England as a very fine white clay, which contains more alumina but less iron than the untreated clay. Of this material about 130,000 tons are sent to the Potteries every year. In Staffordshire what is called Cornish stone is also used. This is a kind of granite in which the felspar retains its alkaline elements, and is also useful as a vitrifying agent. Ground flints, too, are employed in the manufacture of earthenware. Ball clay forms the foundation of earthenware; flint is simply the whitening material. The addition of Cornish clay makes the body still whiter and less liable to break under a heavy weight and changes of temperature, while Cornish stone renders the ware more compact and of a closer texture. A mixture of these substances when fired would not produce earthenware of a perfectly white colour. The iron contained in them would impart a yellow tinge. This is overcome by adding oxide of cobalt, which neutralises this tendency so completely that white ware is produced.

It is unnecessary to describe at any length the process of manufacture. Once the ware is made it is gently dried by exposure to the ordinary air; afterwards it is placed in saggers and fired in large cylindrical ovens, slowly at first to prevent too sudden evaporation of moisture and to prevent splitting. When the ware has undergone its first firing it is known in the trade as _biscuit_. Common terra-cotta and stoneware only require one firing, but for all English ware it is necessary that it should be placed twice in the oven so as to get a denser texture of the ware, also for the purpose of glazing, or that process whereby the article is dipped in a liquid in which usually raw or ground vitrified lead is suspended. If the ware is to remain white, it is, after it has been biscuited, sent to the dipping department to be glazed, and if it is to be decorated and sold as an inexpensive ware it goes in addition to the printing shop, where by means of thin paper transfers it receives the desired coloured impression. The more expensive ware is painted by hand in the ordinary way by means of small brushes. In underglazed colouring the decorated ware is placed in a kiln and brought to a red heat so as to burn off the oil in the colouring. The earliest glaze used in Staffordshire contained galena or sulphide of lead. The materials used for glazes are the same as those for the body, viz., silica as found in flint, and felspar, to which is often added Cornish stone. These are called the hard materials, and they are vitrified by such fluxes as oxide or carbonate of lead, borax or boric acid, potash, soda, carbonate of lime and barytes. In the Potteries each manufacturer has his own receipt for glazes, and he guards it with a conservatism that to outsiders seems unnecessary in these days of advanced chemical research. The ingredients or the glaze can be rendered very insoluble by vitrifying them in a reverbatory furnace or crucible by exposure to an intense heat, whereby a compound like green glass is obtained, which is called a _fritt_. This is subsequently ground and mixed with water. Into this liquid the ware is dipped, and having been biscuited, the porous ware rapidly absorbs the water, leaving the solid particles of the glaze on the surface. Instead of fritting the lead, many manufacturers until lately simply added raw lead, _i.e._ white lead or carbonate, to the other ingredients in the dipping tub, and it is owing to persistence in this practice that lead poisoning has been so prevalent in the Potteries. After the ware has been dipped in the glaze it is fired for a second time in a manner similar to the first, only in smaller ovens, and with greater care, the individual pieces being better separated from each other. On removal of the ware from the oven it is ready for the market. In most factories the ware, after having been dipped, is dried and _cleaned_ by women, _i.e._ the borders are scraped with a knife to remove any surplus glaze. When this process of cleaning is conducted over a trough that is aspirated there is very little dry glaze dust scattered about the room, but if performed in a room without proper ventilation the atmosphere becomes dusty and dangerous. Ware cleaning ought never to be conducted in the same room as the dipping.

What is called _porcelain_ or _china_ differs slightly from earthenware. There are three kinds of porcelain: (1) that made from kaolin and felspar, with the addition of quartz: this is manufactured in Limoges in France; (2) soft porcelain, which was formerly made at Sèvres, near Paris; and (3) English porcelain, which, like the first, is made from kaolin and Cornish stone, but differs from it in containing calcined bones. For hard porcelain, the glaze is made from felspar, which contains a variable quantity of quartz, while in the glaze used for the other two there is usually some silicate of lead and borates, the presence of which allows of a lower temperature being used for the biscuited ware. Thirty-five firms in the Potteries make china, and 195 earthenware.

The population of the Potteries and of the district immediately round about is probably not less than a quarter of a million. It is estimated that there are from 46,000 to 50,000 people working in the Potteries, of whom 4703--viz., 3123 males and 1580 females--are engaged in what might be called lead or dangerous processes. In his Annual Reports the Chief Inspector of Factories shows that in 1898 there were 457 cases of lead poisoning notified to the Home Office from the Potteries, 249 in 1899, and 200 in 1900, whereas for the same periods the following numbers were reported from all other trades combined, excluding house painters, 1278, 1258, and 1058. The number of persons working “in the lead” in the Potteries in July 1898 was 4703, and were classified as follows:--

NUMBER OF PERSONS employed in Processes where Lead is used in
the manufacture of Earthenware and China, North Stafford
District, July 1898.

+------------------------+---------------+---------------+---------------+ | Persons Employed. | Under 13. | 13 to 18. | Over 18. | +------------------------+------+--------+------+--------+------+--------+ | |Males.|Females.|Males.|Females.|Males.|Females.| |(_a_) Dippers | ... | ... | 9 | 15 | 486 | 66 | |(_b_) Dippers’ | | | | | | | | Assistants | 7 | ... | 408 | 49 | 103 | 58 | |(_c_) Ware Cleaners | ... | ... | 15 | 76 | 90 | 382 | |(_d_) Glost Placers | ... | ... | 58 | 8 | 1747 | 38 | |(_e_) Majolica | | | | | | | | Paintresses | ... | ... | ... | 62 | ... | 233 | |(_f_) Ground Layers | ... | ... | ... | 9 | 89 | 373 | |(_g_) Colour Dusters | ... | ... | ... | 24 | 7 | 118 | |(_h_) Enamel Colour & | | | | | | | | Glaze Blowers | ... | ... | ... | ... | 9 | 12 | |(_i_) Other persons | | | | | | | | coming in contact| | | | | | | | with lead, not | | | | | | | | enumerated in the| | | | | | | | foregoing list | ... | ... | 19 | 13 | 76 | 44 | +------------------------+------+--------+------+--------+------+--------+ | Totals | 7 | ... | 509 | 256 | 2607 | 1324 | +------------------------+------+--------+------+--------+------+--------+

Males 3123
Females 1580
----
Total 4703
====

At the date of the Report on the Use of Lead in Potteries, presented by Professor Thorpe and myself to the Home Secretary (1899), the total number of cases of lead poisoning in the Potteries during the previous three years, _i.e._ since the Act of 1895, as to compulsory notification, came into force, was:--

Males 478
Females 607
----
Total 1085
====

These were distributed thus:--

NUMBER OF PERSONS reported as suffering from Lead Poisoning
during the years 1896, 1897, and 1898.[67]

+------------------------+-----------------------------------------------+ | | 1896. | 1897. | 1898. | | +-------+-------+-------+-------+-------+-------+ | | 13 to | Over | 13 to | Over | 13 to | Over | | | 18. | 18. | 18. | 18. | 18. | 18. | +------------------------+---+---+---+---+---+---+---+---+---+---+---+---+ | | M.| F.| M.| F.| M.| F.| M.| F.| M.| F.| M.| F.| |Dippers | 3| 1| 50| 14|...|...| 48| 9|...| 1| 41| 6| |Dippers’ Assistants | 9| 6| 3 | 12| 26| 2| 3| 8| 14| 2| 6| 17| |Ware Cleaners |...| 3| 2 | 54|...| 2|...| 66|...| 3| 1| 55| |Glost Placers | 1|...| 57| 1|...|...| 53| 2|...|...| 48| 1| |Majolica Paintresses |...| 1|...| 38|...| 7|...| 41|...| 4|...| 27| |Ground Layers |...|...|16 | 34|...|...| 15| 40|...|...| 10| 45| |Colour Dusters |...| 2|...| 11|...| 9|...| 1|...| 6|...| 9| |Litho. Dusters, or | | | | | | | | | | | | | | Cleaners in making | | | | | | | | | | | | | | Litho. Transfers |...| 10|...| 11|...| 8| 4| 10| 4| 8| 6| 9| |Other persons coming in | | | | | | | | | | | | | | contact with lead, not | | | | | | | | | | | | | | enumerated in the | | | | | | | | | | | | | | foregoing list |...| 1| 10|...|...| 2| 25| 5|...|...| 22| 3| +------------------------+---+---+---+---+---+---+---+---+---+---+---+---+ | Totals | 13| 24|139|175| 26| 30|148|182| 18| 24|134|172| +------------------------+---+---+---+---+---+---+---+---+---+---+---+---+

Age. 1896. 1897. 1898.
13 to 18 { Males 13 26 18 = 57
years. { Females 24 30 24 = 78

Over 18 { Males 139 148 134 = 421
{ Females 175 182 172 = 529

Grand total in 3 years { Males 478
{ Females 607
----
1085
====

COMPARISON of Number of Persons “Working in Lead” in July
1898, with number of cases of Lead Poisoning reported
in year 1898.

+----------------------------+---------------+---------------------------+ | | Workers. | Lead Cases. | | +------+--------+------+-----+--------+-----+ | |Males.|Females.|Males.| Per |Females.|Per | | | | | |cent.| |cent.| +----------------------------+------+--------+------+-----+--------+-----+ |Dippers | 495 | 81 | 41 | 8.2 | 7 | 8.6 | |Dippers’ Assistants | 518 | 107 | 20 | 3.9 | 19 |17.8 | |Ware Cleaners | 105 | 458 | 1 | 1.0 | 58 |12.7 | |Glost Placers | 1805 | 46 | 48 | 2.6 | 1 | 2.0 | |Majolica Paintresses | ... | 295 | ... | ... | 31 |10.5 | |Ground Layers | 89 | 382 | 10 |11.3 | 45 |11.8 | |Colour Dusters and Litho. | | | | | | | | Dusters | 16 | 154 | 10 |62.5 | 32 |20.8 | |Other persons in contact | | | | | | | | with lead | 95 | 57 | 22 |23.2 | 3 | 5.3 | +----------------------------+------+--------+------+-----+--------+-----+ | Totals | 3123 | 1580 | 152 | 4.9 | 196 |12.4 | +----------------------------+------+--------+------+-----+--------+-----+

These statistics were obtained for Professor Thorpe and myself by Mr J. H. Walmsley, H.M. Inspector of Factories, Stoke-on-Trent, and are reproduced from our Conjoint Report to the Home Secretary on Lead Compounds in Pottery. From these figures it is seen that of the total male workers 4.9 per cent. become “leaded,” whereas of the female workers, who form the smaller body, the proportion is as high as 12.4 per cent.; and if the official figures for 1897 had been taken, the results, it is believed, would have been even higher. Before Professor Thorpe and myself commenced our investigation of lead poisoning in the Potteries, _Special Rules_ had been issued by the Chief Inspector of Factories in 1898, the good effects of which were already being felt at the time of our visits to Staffordshire. From the Annual Report of the Chief Inspector of Factories it appears that in 1900, 200 cases of lead poisoning in the Potteries were reported, as against 249 notified in 1899. Dr Morison Legge in alluding to this subject remarks that it is natural to attribute the diminution partly to the new _Special Rules_ (1898), and to the fact that in some factories the use of raw lead has been discontinued. The numbers of cases of both sexes in 1899 are much fewer than in 1898; but of the total persons, it is to be noted that whereas females constituted 55.2 per cent. and males 45.8 per cent. during 1898, the reverse occurs in 1899, viz., 51.4 per cent. males and 48.6 females. The alteration in sex distribution among persons attacked is attributed by Dr Morison Legge to the medical examination, in which adult males did not participate. It would appear, too, that there is a diminution in the number of severe cases reported, a circumstance which is also attributed to the medical examination. The diminution is most observed among ground layers and colour dusters, but not in ware cleaning or dipping operations.

What are called the dangerous processes of pottery manufacture are those in which the worker is brought into contact with lead. The preceding tables show that from lead poisoning a very high percentage of colour and litho-dusters suffer, also that dippers’ assistants, ground layers, ware cleaners, majolica paintresses, and dippers run a considerable risk from plumbism. There are fewer women than men working as dippers, and in this department the incidence of plumbism is nearly equal in the two sexes. With the exception of glost placing, _i.e._ filling the ovens with the ware about to be fired, and which is heavy labour and only fit for men, females predominate in all the other departments. From these figures it is seen that males who are colour dusters suffer in much larger proportion from lead poisoning than do females, but in nearly all the other processes it will be observed that the percentage of lead poisoning is higher in females than males. It is the lead processes that have justly caused pottery manufacture to be regarded as one of the dangerous industries, and whatever may be said to the contrary, women, especially young women from seventeen to thirty years of age, and all _young_ males or females, are especially susceptible to plumbism. Lead poisoning in pottery manufacture has for long been known, but neither had the Home Office, nor employers and the public, any adequate idea of the extent to which the evil prevailed until industrial plumbism became notifiable. It was with the view of throwing light upon this subject that the Secretary of State invited Professor Thorpe and myself, in May 1898, to institute a special inquiry into the hygienic questions involved in the use of lead in pottery processes, and to ascertain--

(1) How far the danger may be diminished or removed by
substituting for the carbonate of lead ordinarily used, either
(_a_) one or other less soluble compound of lead, _e.g._ a
silicate; (_b_) leadless glaze.

(2) How far any substitutes found to be harmless or less
dangerous than the carbonate lend themselves to the varied
practical requirements of the manufacturer.

(3) What other preventive measures can be adopted.

Professor Thorpe and myself, either singly or together, visited not only the potteries in Staffordshire and in Scotland, but several of the leading manufactories on the Continent, _e.g._ at Delft, La Louvière, Maastricht, Copenhagen, Charlottenburg, Dresden, Limoges, Choisy-le-Roi, etc., and our opinions and recommendations are embodied in a Blue Book which was presented to the Home Secretary, Sir Matthew White Ridley, in February 1899. These, it is to be hoped, will ultimately form the basis of legislation for the trade in this country. At present our recommendations have been challenged by the manufacturers, and are the cause of considerable dispute between the master potters of this country and the Home Office. I therefore reproduce our recommendations:--

(1) That by far the greater amount of earthenware of the class
already specified, _i.e. white and cream-coloured ware_, can
be glazed without the use of lead in any form. It has been
demonstrated, without the slightest doubt, that the ware so made
is in no respects inferior to that coated with lead glaze. There
seems no reason, therefore, why in the manufacture of this class
of goods the operatives should still continue to be exposed to
the evils which the use of lead entails.

(2) There are, however, certain branches of the pottery industry
in which it would be more difficult to dispense with the use
of lead compounds. But there is no reason why, in these cases,
the lead so employed should not be in the form of a fritted[68]
double silicate. Such a compound, if properly made, is but
slightly attacked by even strong hydrochloric, acetic, or lactic
acid. There can be little doubt that if lead must be used, the
employment of such a compound silicate--if its use could be
insured--would greatly diminish the evil of lead poisoning.

(3) The use of raw lead as an ingredient of glazing material, or
as an ingredient of colours which have to be subsequently fired,
should be absolutely prohibited.

(4) As it would be very difficult to ensure that an innocuous
lead glaze shall be employed, we are of opinion that young
persons and women should be excluded from employment as
dippers, dippers’ assistants, ware cleaners after dippers, and
glost placers in factories where lead glaze is used, and that
the adult male dippers, dippers’ assistants, ware cleaners,
and glost placers should be subjected to systematic medical
inspection.

These were our recommendations, and while they received a considerable amount of approval throughout the country, some of them, as might be expected, have been the subject of hostile criticism on the part of the pottery manufacturers. It should be borne in mind that a few years previous to our inquiry a Committee appointed by Mr Asquith, then Home Secretary, and composed of Mr S. W. May, H.M. Superintending Inspector of Factories (Chairman), Dr John T. Arlidge, Mr W. D. Spanton, F.R.C.S.E., Mr A. P. Laurie, M.A., Mr J. H. Walmsley, H.M. Inspector of Factories, and Mr W. D. Cramp, H.M. Superintending Inspector of Factories (Secretary), had reported to the Secretary of State, and made certain recommendations, including one specially by Mr Laurie, in which it is suggested that the manufacturers should be circularised from the Home Office to experiment with and test the uses and the effect upon the health of the workpeople of glazes and colours in which all the lead had been fritted; also the practicability of making a glaze that would be harmless to those employed in the manufacture, and at the same time would not injure the ware. It remains a cause of disappointment that, considering the assistance rendered by the 1893 Committee, the pottery manufacturers did so little to introduce the improvements that were recommended so as to minimize the evils that were yearly increasing. Periodical medical examination of the workers, male as well as female, they certainly encouraged, and they admit that the result was beneficial. There is a feeling that, had the manufacturers bestirred themselves a little more in the direction of using properly fritted lead compounds instead of raw lead in the glaze, and of again experimenting with leadless glazes to see what they could accomplish, plumbism in pottery manufacture would have materially diminished, our inquiry might not have been necessary, and certainly the recommendations made by Professor Thorpe and myself would not have been viewed, as they are by employers, in the light of a menace to the industry and a check to its commercial prosperity.

If there is one thing upon which the British public has made up its mind in regard to some of the important labour and social questions of to-day, it is, that there ought to be fewer cases of lead poisoning in the manufacture of pottery generally, and that plumbism should be practically abolished in the production of certain kinds of earthenware. It would therefore be rather to the advantage of the industry than otherwise, were the Staffordshire employers to meet the wishes of the public in this respect, by making a greater effort to produce ware dipped in leadless glaze. When the Home Secretary published our recommendations, and stated to employers that it was his intention to give effect to them, the pottery manufacturers assumed an attitude partly of agreement and partly of disagreement. They at once stated their willingness to discontinue the use of raw lead in glazes; they asked for a lengthened period to test and experiment with fritted lead, while in regard to leadless glazes they have taken up the position which, up to the time of writing, may be regarded as one of no compromise. The abolition of raw lead, if carried out, would mark a very important stage in the pottery manufacture of this country, and of itself would do much to reduce the number of cases of lead poisoning. The use of fritted lead compounds would also prove helpful; but in order to obviate the risks of plumbism from the use of these substances, the fritting of the lead compounds has to be done carefully, for although less soluble than raw lead, yet plumbism has followed their use. A simple silicate of lead possesses advantages over the carbonate, both in its physical and mechanical characters; it is, for example, less dusty and clammy than either white or red lead, and is more easily removed from the skin by washing. Such an ordinary silicate may contain as much as 70 per cent. of lead oxide, and 25 per cent. of silica, with small quantities of alumina, lime, magnesia, and alkalis, corresponding in fact to a crude mono-silicate, “and this compound, which is generally understood as ‘fritted’ lead, is hardly less soluble in acids than basic lead carbonate,” besides “glazes in which the whole of the lead has been fritted as a properly compound lead silicate--that is, fritted directly with the other components of the glaze, so as to form a double silicate--have been found to possess greater covering power than a glaze containing the same relative amount of lead in the ‘raw’ state, with the further advantage of enhancing the colour.” When the amount of silica is increased the fritt becomes more innocuous, but there is a limit to which silica can be added to litharge, so as to produce a homogeneous silicate. Even bisilicate of lead is not wholly insoluble in acids. Professor Thorpe found in his experiments, conducted in the Government Laboratory, that it was not desirable the fritted lead should be a simple silicate, also that a properly compounded double silicate could be made that would fulfil all the requirements of the potter, and at the same time be practically insoluble in acids. He suggested the following as a suitable constituent of glaze, and as a compound that would be only slightly attacked by hydrochloric acid, viz.--

Lead Monoxide 22.0
Alumina 7.5
Lime 8.3
Alkalis 3.9
Boracic acid 3.5
Silica 54.8
-----
100.0

This combination can be obtained by “fritting an intimate mixture of litharge, flint, felspar, tincal, and chalk, or an intimate mixture of litharge, flint glass, borax, china clay, and ground flint; or, as is done on the Continent, a portion of the flint may be replaced by white sand, the colour if necessary being corrected by cobalt.” There is a very strong feeling that in Staffordshire the pottery manufacturers have been using more lead than is actually required to make a good glaze. Lead has been used without proper discrimination. As to what the amount of combined lead, calculated as oxide, which the glaze of “glost” ware should contain, the opinion of even practical potters is divided. It has been thought by some that 20 per cent. is required, while others fix the limit at 10. Professor Thorpe found excellent examples of lead-glazed ware in which the monoxide of lead did not exceed 12 per cent. of the total weight of the glazing materials, while on analysing some of the liquid taken from the dipping tubs in the potteries, he found the amount varied from 13 to 24 per cent., and even higher. If, therefore, the use of lead compounds is still to be permitted, and, as has been shown, fritted lead in the form of a simple silicate is not much less soluble than raw lead, it is apparent that, with the view of preventing injurious consequences, their use must be restricted and regulated. It was with this object that the Home Office insisted upon all fritted lead compounds conforming to a certain test of solubility, and it is around this point there is considerable disagreement between the master potters and the Home Office. In a Report on the “Use of Lead in the Manufacture of Pottery,” presented to the Secretary of State by Professor Thorpe (1901), the Government chemist deals, among other things, with the relation between the composition and solubility of lead silicate, as shown in the following table:--

+-------------------------------------------+------------------+--------------+ | | Oxide of Lead | Percentage | | | dissolved by | Composition. | |Fritts arranged in order of Increasing |0.25 per cent. of | ---- | | Solubility. |Hydrochloric Acid.|Oxide of Lead.| +-------------------------------------------+------------------+--------------+ | | Per cent. | | |Preparation from Maastricht fritt (Belgium)| None. | 18.04 | |Preparation from Boch’s fritt (Belgium) | Traces. | 21.83 | |Boch’s fritt | 2.6 | 22.44 | |Ålmström’s fritt (Sweden) | 4.8 | 44.06 | |Maastricht fritt | 5.6 | 18.97 | |Owen’s glaze fritt | 6.6 | 16.23 | |Owen’s fritt | 23.8 | 45.77 | |Doulton’s fritt | 60.4 | 37.92 | |Owen’s lead silicate (No. 2 sample) | 99.6 | 70.40 | +-------------------------------------------+------------------+--------------+

I have not reproduced in the table the percentage composition of the other ingredients of the fritt, but it is maintained that the solubility does not depend upon any of the constituents, nor does any single base or acid increase or decrease continuously as the solubility of the fritt increases. Although in a general sense the solubility increases with the sum of monoxides present in the fritt, yet there is no regular progression. The solubility, according to Thorpe, depends upon the value of the ratio bases/acids which, judging from the results obtained by him, should not exceed 1.45, or thereabouts, if the fritt is to be practically insoluble in 0.25 per cent. hydrochloric acid and be therefore safe. With the view of coming to some understanding upon this question a conference was held between representatives of the pottery industry and the Home Office on 31st October 1899. Two months afterwards the Secretary of State intimated that it was his intention to propose that after a certain interval a standard of insolubility for fritted lead employed in glazes should be observed by the manufacturers--the standard of insolubility being that the glaze should not yield more than 2 per cent. of lead when acted upon by hydrochloric acid, under certain conditions. Permission was granted to manufacturers to submit specimens of fritted lead to Professor Thorpe, so that they might have the necessary chemical assistance if wanted. Several samples were received, and on examination it was found that they could contain amounts of lead ranging from 24 to 53 per cent., and yet be capable of conforming to the standard of solubility required by the Home Office, although generally speaking they yielded slightly larger quantities of lead oxide to dilute hydrochloric acid than the insoluble silicate prepared from Continental fritts. In a short Report by Dr Thorpe, dated 20th November 1900, are published directions for the fritting of lead. The manufacturer, for example, “may, in the first place, fritt together all the materials given in the receipts--that is in one operation. If he chooses to take this course it would, as a matter of economy, be preferable to substitute litharge, if not for the whole of the raw lead, at least for the white lead. It seems absurd to pay for the trouble of putting the carbonic acid and water into the white lead, when these ingredients are expelled by the heat of the kiln. The required alteration in the receipt may easily be calculated from the fact that 1 lb. of litharge contains the same amount of lead oxide as 1.02 lb. of red lead or 1.18 lb. of white lead. Or the manufacturer may make up his fritt by commingling two other fritts. Thus he may fritt together borax, stone and flint, and fritt also the lead oxide, flint and stone, each in such proportions that the two when mixed with the whiting and china clay form a composition containing 18 per cent. of lead oxide.” It was urged by the manufacturers that the 2 per cent. solubility of lead in a glaze would be materially affected by the degree of fineness to which the fritt might be ground, but experiments showed that while within limits increased solubility of the fritt and fineness of grinding were concurrent, yet this question was rather of an academic nature, and had no practical bearing upon the use of fritted lead compounds in pottery. In our Conjoint Report, dated 1889, when discussing the amount of combined lead that might be allowed in glazes, we stated as the opinion of practical potters that it should be from 10 to 20 per cent. We ourselves suggested 12 per cent. Subsequent experience and experiment convinced Professor Thorpe that 12 per cent. is higher than is actually necessary in earthenware and china glaze. Nor does he regard the limit of 2 per cent. of solubility as too hard or stringent a requirement. The manufacturers pressed the Home Office to raise the limit to 5 per cent., but to do this in the face of existing evils was far from helping the object that the Home Office had in view. The stamping out of lead poisoning in pottery manufacture is a most desirable object, and one all must wish to see accomplished without, if possible, any injury to the trade. “If the limit is raised, as suggested, to 5 per cent., it means that the lead in an ordinary earthenware or china glaze, as at present used, may be so soluble that one-third of it may be extracted by very dilute acid at ordinary temperatures in one hour.” More than that, to raise the limit to 5 per cent. would be to throw away all the result of the experience that has been gained by experiments conducted over a period of three years, and would tend to perpetuate the evils that at present exist.[69]

No matter in what form lead is used for glazing pottery, there is always a risk of plumbism. The French pottery manufacturers employ for enamelling purposes a glaze the principal ingredient of which is _calcine_--an alloy of 15 to 20 parts of tin, and 100 parts of lead. An ordinary composition for white glaze for table ware is--

Calcine 44
Minium (lead oxide) 2
Decize sand 44
Sea salt 8
Soda 2

Yellow and green coloured enamels are got by adding to the white glaze a quantity of antimoniate of lead, but for other colours no lead is used. (_Poisons Industriels_, Office du Travail, Paris, 1901, p. 45.)

Since the publication of the Report on Pottery Manufacture in 1899, by Professor Thorpe and myself, in which we recommended the use of leadless glazes for cream and white ware, electrical fittings, sanitary ware, etc., attempts have been made to place leadless glazed earthenware and china on the market. Commercially the thing can be done. The Worcester Porcelain Company, also Messrs Mortlock, Maling & Sons, and others, are willing to supply china finished with a glaze quite free from lead. The Coalport China Company state that they have used a leadless glaze for the past eighty years, and that they have never had a case of lead poisoning in their works. Messrs Maling & Sons, Newcastle-upon-Tyne, regularly produce a large amount of ware dipped in leadless glaze, particularly jam-pots.

In France a circular issued by the Minister of the Interior, and bearing date 19th June 1878, interdicts the manufacture and sale of pottery, either of French or foreign manufacture, glazed by means of oxide of lead which has been incompletely fritted, and which gives up readily oxide of lead to feeble acids. I am not in a position to say how far this has been given effect to.

In potteries where red or brown ware is used plumbism is not unknown. It has generally been traced to the use of red lead. Occasionally lead poisoning from red earthenware potteries, mostly in the form of wrist drop, has come under my notice at the Newcastle Infirmary. Some of the cases have been drawn directly from the immediate district, while others have come from Sunderland. With the view of diminishing plumbism in the manufacture of red and brown earthenware, Professor Thorpe suggested that where employers decline to use fritted lead, on the ground of expense, there would be no practical hardship in adopting the use of ground blue lead or galena, _i.e._ the native ore, instead of red or white lead. It is cheap, but it requires to be ground. The drawback to it is that it gives off sulphur fumes when fired, but the amount of sulphur oxides given off is small to that formed in the combustion of the coal in the oven. It gives a faint yellow or brownish tinge to the glaze, but this does not seem to be objectionable. In visiting potteries in Holland, I found one firm in Gouda which used ground galena for glazing this kind of ware. They had not only every reason to be satisfied with the results, but in the factory plumbism was unknown. Several decades ago galena was similarly used in Staffordshire.

I have dwelt at considerable length upon the question of fritting lead compounds and the use of leadless glazes, both in defence of the attitude which Professor Thorpe and myself have assumed, and to show the reasonableness of our recommendations.

If our recommendations were adopted they would certainly make for better health of the operatives engaged in pottery manufacture. At the time of writing they have not been adopted. Some months ago a statement was issued by a joint committee representing 283 of the 579 manufacturers coming under the Special Rules, challenging our Report. The manufacturers say that it is impossible to glaze the greater part of their ware without lead, and that serious injury will be done to the trade if a radical measure of so sweeping a character is enforced without giving sufficient time to test the products so treated. Employers maintain that from a trade point of view existing regulations are hard enough. They suggest that there should be an extension of the medical examination of all operatives engaged in lead processes quite irrespective of age or sex. The Home Secretary subsequently indicated to the manufacturers the steps he proposed to take with the view of protecting workers from lead poisoning in china and earthenware, viz.--(1) relaxation of the Special Rules for factories or processes in which no lead is used; (2) medical examination of male workers in lead processes; (3) use of fritted lead--six months being allowed before this becomes compulsory; (4) fixing of standard of safety in fritts as regards solubility in acids.

There is everything to show that within the last three or four years the conditions of labour in the Potteries have materially improved, and that there has been a distinct diminution in the number of cases of lead poisoning. The operation of the Special Rules, the periodical medical examinations, and a more restricted use of raw lead have largely contributed to this satisfactory result. A return of cases of lead poisoning reported under the Act 1895, occurring in the manufacture of earthenware and china from 1st January 1899 to 31st December 1900, and presented to the House of Commons by Mr Jesse Collings, 27th February 1901, conveys information upon this particular point. During the year 1899 there were in the Potteries 129 persons suspended from work on account of lead poisoning, and in the following year 95. In 1899, 34 of the 129 persons were ware cleaners, 29 worked in the dipping house, 26 were majolica paintresses, ground layers formed 14 of the total, and 10 were colour dusters, while for 1900 the numbers were respectively 20, 42, 8, 6, 13. The districts of Hanley, Burslem, Tunstall, and Stoke include practically the whole of the North Staffordshire Potteries, where about 46,000 persons are at present employed in the manufacture of china and earthenware, and of whom 4700 are employed in lead processes. Taking, therefore, the cases of lead poisoning in the Potteries for the last four years, they run as follows: in 1897, 446; in 1898, 457; in 1899, 249; and in 1900, 200.[70] Allowing a margin on either side for discrepancies and incompleteness in the statistics, these figures at once show how in a trade that has hitherto been regarded as dangerous the conditions of labour can be materially improved, with a very marked gain in health to the workers. These encouraging results are, it is hoped, only a forecast of others yet to come.

There is considerable discrepancy in the returns of lead poisoning in the Potteries, due to the source from which the statistics have been obtained, and the manner in which the cases have been notified. All the statistics concur in showing a declension of plumbism. From an article in the _Times_, 24th September 1901, the following has been taken:--“That lead poisoning has rapidly diminished among potters and increased among other trades is proved by the following table of cases reported in the last four years, and compiled from the _Labour Gazette_ and other official sources.”

Potters. Other Trades.
1897 469 745
1898 463 954
1899 249 1009
1900 200 1057