Chapter XL: The Chemical Trades

_Introductory Remarks._--Under the title of the chemical trades a very large number of industries must be included which vary widely in the conditions under which the manufacturing operations are carried on. Nor must sight be lost of the great variety of chemicals used in the arts. For instance, in the department of pure chemicals and drugs for medical purposes, we find manufacturers who are engaged in producing small quantities of these substances, with the greatest precautions for cleanliness and care in the details of manufacture. These articles may be manufactured in small vessels by the pound weight at a time. At the other end of the industry we find the manufacture of such chemicals as are used in very large quantities carried on by tons. The whole conditions of such a manufacturing process are necessarily quite different, and we find laboratory fittings replaced by enormous machinery and great furnaces working under open sheds and turning out large quantities of material. It is therefore impossible to deal adequately with an industry of this description, or to give anything approaching a complete survey of the different conditions of employment found in it.

Furthermore, we have allied to the chemical trade others closely resembling it. It is, for instance, a mere arbitrary distinction to separate the manufacture of pigments from that of chemicals, as many of the pigments used at the present day are made by means of chemical processes carried on under similar conditions, and the workmen engaged in these are exposed to similar risks and dangers. The white lead industry, for example, is merely a process of chemical manufacture, although for convenience it is regarded as an industry by itself. There are other industries in which the danger to health in using certain chemicals is even more serious than it is to those actually engaged in their manufacture. For instance, it seems to be far more dangerous to dip match heads in the composition containing small quantities of phosphorus than it is to manufacture phosphorus itself, and many cases occur where lead poisoning results from the use of chemicals containing lead. The greatest danger seems to be for those who are continuously engaged in handling these substances in small quantities rather than for those who deal with the manufacture in bulk. It is evident, then, that as a matter of convenient classification we must strictly limit the meaning of the words “chemical trades.”

Dealing purely with the manufacture of chemicals themselves, we may, I think, lay down this general principle, that there is not necessarily any danger to the workman in manufacturing the most poisonous substances, if reasonable precautions are taken. Most chemicals are made by a wet process, and are crystallised or precipitated from the solutions, and therefore the danger from the inhaling of poisonous dust is not present. If deleterious gases are evolved, suitable arrangements can be made for preventing them escaping into the laboratory: moreover, we find that firms engaged in the manufacture of fine chemicals usually prepare a great variety of substances, so that the workmen are not always engaged upon the same process, and the risk of accumulated poisoning is diminished.

The experience of scientific chemists in their own laboratories goes to show that for many years experiments may be carried on with the most dangerous substances, including gases of a poisonous nature, and that they may work day after day in an atmosphere frequently loaded with the fumes of strong acids and other substances, and yet not suffer any serious damage. In the manufacture of miscellaneous chemicals and drugs conducted on a comparatively small scale, there is no reason, I believe, to look for any serious difficulty in making the work perfectly healthy. Good ventilation and obvious precautions are all that are really necessary. But when we come to consider the manufacture of certain chemicals in very large quantities, then we find conditions which make it very difficult to protect the workmen from injurious consequences. The heaviest part of the chemical trade is that devoted to the manufacture of hydrochloric and sulphuric acids, carbonate of soda, caustic soda, and bleaching powder. These chemicals are usually made in one establishment, as part of one process, or in establishments closely allied to each other, and we shall find that there are three distinct methods of producing some, at any rate, of these chemicals.

_The Le Blanc Process._--To deal first with the process by which all these substances can be manufactured, and which is the oldest and still the most important, we shall consider in some detail the manufacture known as the Le Blanc process, which is carried on in this country by the United Alkali Company and others. We shall find that the manufacturing processes necessitate the workman being exposed to the weather in open sheds, and that he is carrying on operations involving considerable bodily exertion before furnaces, and is exposed to various deleterious gases. Probably the fact that his work is carried on in open sheds, while making him more liable to sudden chills after working before the furnaces, is, on the whole, beneficial, as he is supplied in this way with fresh air. In fact it would be impossible to carry on many of the operations under any other conditions. As has been shown by statistics, the agricultural labourer, in spite of his exposure to inclement weather, has the longest life of any class of workmen. We may say, then, that the chemical worker, as his employment is practically an outdoor one, has this much to the good; but we cannot compare the air which he breathes in the chemical works with that which is breathed on the country farm.

The processes of Le Blanc manufacture are as follows: The first is the production of sulphate of soda or salt cake. This is produced by acting upon common salt with sulphuric acid or oil of vitriol. We shall have to consider the conditions of the manufacture of sulphuric acid itself, but it will be simpler in the meantime to assume that we have sulphuric acid supplied to us. Its manufacture is usually carried on in the same works in which the salt cake is made. The sulphuric acid and salt are heated on the bed of a furnace, and are raked and moved about by the man in charge, until the decomposition of the salt is complete, and it has been converted into sulphate of soda. During this process torrents of hydrochloric acid gas are set free from the mass, and are drawn away from the furnace by means of a Root’s blower or some similar contrivance.

The hydrochloric acid gas has a suffocating and irritating effect when breathed, and if present in any considerable quantities in the air, makes it quite impossible for any one to stand the suffocation and irritation produced. Even in smaller quantities the irritation of the air-passages is so great that it must in course of time prove injurious to the workmen. If we could obtain an ideal system, there seems to be no reason why workmen should be exposed at all to this irritating gas. The furnaces are, of course, arched in, and the gas is drawn off as it is generated. The main danger of exposure to the gas comes when the workman rakes the salt cake from the furnace into barrows, for removal to the next operation. Here a considerable improvement has been made of late years. The salt cake is raked into an iron box, which is connected to the furnace draught, so that the gases are drawn away while the salt cake cools, and the box is not removed from this position until by this means most of the fumes of acid have been given off.

Notwithstanding these improvements, hydrochloric acid gas is found to be present more or less in the neighbourhood of these furnaces. The state of repair in the furnaces themselves, the condition of the weather, the amount of moisture in the air, the successful working of the acid towers, the rate at which the workman is trying to get out his material, and consequently not allowing it to cool properly in the iron box--all these conditions are present, and any of them may result in the presence of a certain amount of gas. It is only necessary to be in a town like St Helens on a moist evening to realise the fact that from these various chemical works large quantities of hydrochloric acid and other gases are evidently escaping.

In order to protect himself to a certain extent from the hydrochloric acid, the workman either wears a flannel muffler tied over his face, or he bites a piece of flannel between his teeth and breathes through it. The fumes of acid quickly cause the teeth to rot away, and it has been suggested that this biting of the flannel, which gets full of acid, is one of the main causes of the rotting of the teeth. I have no evidence, however, on this point. My impression is that the rotting away of the teeth will take place whether flannel is held between the teeth or is wrapped over the mouth. Besides being exposed more or less to hydrochloric acid gas, the man is also working before a furnace door, in an open shed, and his work is of a very heavy character, so that he usually wears a minimum of clothes and perspires freely. He is thus exposed to constant chills, and to the risk of developing some pulmonary disease.

The custom of the chemical trade is to divide all work of this character into shifts of twelve hours each, though as a matter of convenience the workmen sometimes arrange to take shifts of eleven and thirteen hours. During the twelve hours the workman is supposed to have sufficient time for his meals, but he does not leave his furnace; his food is brought to him, and he so arranges his work that he is able, to get his meal while waiting for the next operation to take place. His work at the furnace is not absolutely continuous. It would be impossible for any human being to carry on such heavy muscular labour continuously. He has to watch the materials, to stir them and rake them about at the proper intervals, and to remove the charge when completed, and to distribute a new charge in the furnace. But as the method of payment universally adopted in the chemical trade is by the quantity of material turned out, he is naturally anxious to turn out as much as possible, and he produces with considerable regularity the same quantity of stuff from day to day.

The amount of labour involved in this would be impossible to a muscular man who had not been trained to it. The mere exposure to heat would make it very difficult. But it must not be supposed, that because a man going to this work for the first time would find the labour and the heat involved quite intolerable that it is so to the salt cake worker. The extraordinary power of adaptation which we find in the human subject enables him to carry out these arduous operations with comparative ease, and so far does this adaptation go, that the men working beside him, whose business it is to wheel barrow loads of the weighed chemicals to the furnace door, can wheel barrows all day, but could not carry out the furnace operations; while the furnaceman, if put into the yard, where he has general labouring work to do, will be found at first very unfit for such toil, and will do the best he can to get back to his furnace work again.

Besides the long hours involved, the exposure to the heat of the furnaces tends to make such men heavy drinkers, and I think it is the universal experience in the chemical trade that such is the case. I believe that inquiry would show that the quantity of alcoholic liquor that one of these men can take, without any apparent injurious effects, is extraordinary. In the end these drinking habits tell, and the result is that the health of the workman rapidly breaks down.

We have then four conditions which are acting prejudicially--exposure to the fumes of an irritating gas, exposure to high temperature from the furnaces, exposure to cold and chills working in an open shed, and the tendency to drink heavily when away from work. I have described these conditions in considerable detail, because the work at the salt cake furnace is so similar to that carried on in many other operations in chemical works, that it may be taken as fairly typical. The men employed in this industry are very largely Irish labourers. If they are not of Irish extraction, they are principally country labourers from the surrounding districts. The comparatively high wages earned are, of course, a temptation. A man may change from salt cake to a black ash furnace, but he is still engaged in similar operations. The work is of so peculiar a character, that a man who has once got adapted to it is not suited for other purposes. When no longer fit for so arduous a task, we may find him employed in odd jobs about the yard, acting as a night watchman, or performing some of the many miscellaneous jobs that require to be attended to in chemical works.

In the earlier inquiries into the effect on health of this and other processes in the chemical trade, very different opinions were expressed as to whether the operations which these men had to carry on, while undoubtedly of a disagreeable character, had really a serious effect upon their health. I shall not discuss this at the present stage, but I think it is proved, in spite of the difficulties, which I shall refer to later on, of obtaining definite statistics on this point, that the injury to health is of a definite and serious character. I shall also reserve for general discussion the question as to the long hours of labour, and how far that may be dealt with and improved.

The salt cake after it leaves the furnace is mixed with limestone and coal in a black ash furnace. After being heated and stirred in this furnace for a sufficient length of time, it is poured out in a molten condition, wheeled away to cool, is broken up, and the soda dissolved from it in the black ash vats. This operation of decomposing the salt cake used to be carried on in furnaces worked by hand. Such furnaces have practically disappeared, and with their disappearance a form of labour as arduous as the work of the salt cake man has also gone. Large revolving mechanical furnaces are now used for this operation, and although the labour of tending these furnaces is arduous, yet the conditions are very much improved upon those which prevailed in the old days. No fumes result in this operation, so that the workman is not exposed to deleterious gases.

After the soda has been dissolved it is subjected to various processes, according to the product which may be required. It may be converted into soda ash, into soda crystals, and into caustic soda. All these operations involve boiling, furnacing, and similar processes, but there is nothing to be said about them of special interest, except the final operation in the manufacture of caustic soda.

In order to make caustic soda, the liquors, after treatment with lime, are evaporated in large cast-iron cauldrons some 15 feet in diameter. As the liquor gets more and more concentrated, the temperature keeps rising, until finally the cauldron is full of red-hot caustic soda, which when it is finished is bailed into iron drums and there solidifies and is ready for sale. These great cauldrons of red-hot caustic are, of course, dangerous, as the substance will produce very serious injuries, if by any accident it gets out of the pot, while a drop of water will cause it to spurt, and other accidents may happen, causing similar spurting of this liquid. We find accordingly that burns are apt to happen in the caustic shop, although they are seldom of a serious character, and occasionally men have lost their lives from slipping and falling into the caustic pot.

Some of these cases were discussed in the inquiry which was made in 1893 into the chemical trades, and certain precautions were suggested for preventing such accidents in future, and were embodied in the special rules. The most important of these was taking care that the top of the pot should be at least 3 feet in height above the ground, and that the brickwork should slope to the top, and should have no ledges upon it where the workman could place his foot.

But while the manufacture of caustic may and does lead to accidents, there is nothing in the actual process of manufacture itself which seems to be injurious to the workman, beyond the exposure to heat and cold. The work of the caustic finisher is not nearly so continuous or so arduous as that of the furnaceman. He is usually highly paid, and requires to be a man of considerable skill, for the turning out of a white caustic of a high strength depends upon long experience, as well as great care in its manufacture.

The next process to be considered is the manufacture of bleaching powder from the hydrochloric acid which was given off during the operations in the salt cake furnace. In practice there are two ways of dealing with this substance, with the view to producing chlorine gas, from which bleaching powder is prepared. Either the hydrochloric acid is decomposed in large stone-covered vessels, known as stills, by means of manganese mud, the chlorine gas evolved being carried away through suitable pipes to the bleaching chambers; or the hydrochloric acid gas is passed direct from the salt cake furnace, and without condensation is mixed with proper proportions of air and steam; it is then decomposed by being brought into contact with specially prepared material, and the chlorine gas liberated. The first process is known as the Weldon process, and chlorine gas produced by decomposition of hydrochloric acid and manganese mud is known as Weldon gas. The second process is known as the Deacon’s process, and the gas is called Deacon gas.

I have mentioned both these processes because the method of preparing chlorine makes a considerable difference in the way in which bleach is prepared from gas. In order to prepare bleaching powder we must expose freshly slaked lime to the gas. The lime will then absorb the chlorine gas, forming a compound known as bleaching powder, from which chlorine can be very readily evolved, mere exposure to air and carbonic acid gas being sufficient to cause a slight decomposition to go on.

It is a matter of great importance to the manufacturer to get as high a percentage of available chlorine into every ton of bleaching powder that he sells as he can, as the buyer of bleaching powder naturally objects to paying carriage on a weak article.

As bleach is always slightly decomposing and losing in strength, it becomes specially important for export purposes, where it may be exposed to long voyages, to make it as strong as possible before it is sent away. We have then the production of an unstable compound, which can only be prepared at full strength, say 38 per cent., by taking great care in the conditions of manufacture, a compound which is always slightly decomposing, and which, if the conditions of manufacture are only slightly altered, will possibly lose rather than gain in strength in the final stages of its manufacture. For example, in order to be able to meet the competition from the Continent and America, it is necessary to turn out this product at as high a percentage of strength as possible. The bleach below 35 per cent. in strength is not saleable, except at a very reduced price, while bleach of 38 per cent. strength is considered to be of the highest quality. It is a matter of the utmost importance to the manufacturer to obtain this 2 or 3 per cent. of strength. Many of those who have discussed the manufacture of bleach, and have talked of improved mechanical processes, have not realised how difficult and delicate a business the production of bleach of full strength really is. These facts should be kept in mind when the chemical manufacturer is condemned for what is called his crude and old-fashioned methods of making this article.

If we are going to make bleach from Weldon gas, we are dealing with gas which contains a very high percentage of pure chlorine, and, consequently, the conditions for successful manufacture are quite different from those prevailing in the case of Deacon gas, in which we have only some 7 per cent. of chlorine present. The manufacture of bleach from Weldon gas is carried on to-day as it has always been, by spreading lime over the floors of chambers, which are at the present time usually made of lead, and passing the gas into these chambers, and allowing it to be absorbed by the lime. These lead chambers are of varying size, but are usually about 100 feet long, 30 feet broad, and about 6 feet high. The lime is spread over the floor, and is made up into ridges by means of a wooden rake. The doors are closed and the chlorine gas is allowed to enter. The absorption process is carried on for two or three days. During that time the lime is taking up the chlorine gas, and forming the compound which we call bleaching powder. Samples are withdrawn from time to time, the supply of fresh gas is stopped, and the lime is allowed to continue absorbing the gas still remaining upon it in the chamber. When this operation has gone as far as it can, and the bleach has reached full strength, then the chamber is again connected to another chamber, containing fresh lime, and this second chamber is then connected to a pipe and subjected to a gentle suction so as to cause a slight current from chamber No. 1 to chamber No. 2. The doors of the first chamber are now slightly opened, so as to admit a little air, and the remaining chlorine gas is then gently drawn off into the chamber which is freshly limed, while air passes in and takes its place. The doors are then thrown wide open, and free admission of air is allowed. The chamber cools, and the greater part of the gas is removed; but complete removal of the gas is not practicable, as the powder itself is always slightly decomposing, and if left long enough on the chamber floor would soon cease to be saleable bleach.

The quantity of gas which may be left in the chamber when the bleach is packed has been laid down in the Act of Parliament dealing with injurious gases from chemical works, and the works’ chemist is expected to test the air in the chamber and enter the result in a book which is inspected from time to time by the Alkali Inspector. These inspectors are not appointed under the Factory Acts. Their function is to prevent the escape of injurious gases which may injure neighbouring property. It must be remembered, however, that the bleach is always decomposing, and in summer weather the decomposition of the bleach is going on very rapidly, and unless it is packed with great promptitude it will lose in strength, while, on the other hand, the fact of this decomposition going on makes the work of packing more disagreeable.

The method of packing is as follows:--The bleach packer wraps his face in roll upon roll of flannel, the flannel being drawn over his mouth and leaving the nostrils free. These layers of flannel stand out some three inches beyond his face, and have to be of just the right dampness to prevent the gas reaching his lungs. He then puts on leather goggles to protect his eyes, and ties a piece of paper round his trousers to keep the bleach from attacking them. He then enters the bleach chamber and rapidly shovels the powder through holes made in the floor. Under these holes are shoots down into the casks which are underneath the bleaching chamber, and a covering is attached to the shoot and tied round the sides of the cask, preventing the bleach from escaping as it goes down. In this way the bleach is packed.

This operation of bleach packing is the most disagreeable to which the man in charge of the bleach is subjected. The chlorine rises from the bleach as it is disturbed, and it would be impossible for any one to remain for a few seconds in a bleach chamber unless he was protected from breathing the gas in the way I have described. On the other hand, such wrappings make breathing very difficult. In fact a man who has not got accustomed to the bleach packer’s flannel would imagine that he was going to die of suffocation, and could not bear it round his face for more than a few seconds. While the bleach packer leaves his nostrils free, he is careful to breathe out from them, while he inhales through the flannels. He may stay from twenty to forty minutes inside the chamber, then come out and take fresh air, then put on his flannels and go back again, and in the course of a day he may thus do from two or three to five or six hours’ bleach packing. The bleach chambers come up to strength in succession, and when one of these is up to strength the product is packed as rapidly as possible, and the chamber prepared for another operation. A great part of the bleach packer’s time is spent in merely looking after his bleaching chambers, seeing that the lutes are tight, that the gas is passing properly into the chambers, and so on. His life consists of periodic leisure combined with the most arduous and exceptional form of toil.

The exact conditions vary in different works, but it is usually found that the bleach packer also prepares the chamber with lime, and he may also prepare the lime himself and sift it. In large works the duties of sifting and slacking the lime are performed by a special set of men. This preparation of the lime is also a very unpleasant process, as it involves working in clouds of lime, which settle on the body and clothes, and is inhaled in considerable quantities. The lime-dresser rubs his arms and face over with grease and has also to roll his face in a flannel, but does not require to put on anything like the number of layers which are necessary in the case of the bleach packer exposed to chlorine gas. In the case of the Deacon process, the arrangement is somewhat different. The lime is distributed on shelves, and is finally removed by being pushed from these shelves down suitable holes, by means of openings from the outside; so that the Deacon man does not go into the chamber, as he does in the case of Weldon gas.

Besides the exposure to the chlorine gas under the conditions of packing, it must be remembered that, in carrying on operations on a large scale with gas having the corrosive properties of chlorine, many little escapes of gas will take place, and that accidents from this source will be found to happen more frequently when the men, not expecting such an escape, are not, consequently, prepared for it, than from actual breathing of the gas during the process of packing.

It is unnecessary to describe the effects of chlorine when breathed. A person has himself to experience the peculiarly suffocating and irritating properties of this gas, in order to appreciate its qualities. But while the inconvenience and discomfort produced are very great, and may result in vomiting and irritation of the bronchial passages lasting for some days, yet the discomfort is greater apparently than the permanent injury to health. Insensibility and death have been produced, but such results are rare. It often happens that workmen in chemical works get “gassed” accidentally, and consequently feel great irritation of their respiratory passages, and have a feeling of suffocation, followed by vomiting, but these symptoms are temporary in their duration, and do not appear to cause permanent injury. Any one who is familiar with chemical works has been gassed occasionally, and yet he has found no permanent harm come from it.

But when we come to the question as to whether the continuous exposure to this gas, combined with work under the peculiar conditions necessary in the case of the bleach packers, does not ultimately undermine the health of the workers, we approach a more difficult problem. These men are necessarily men of great physical strength and in the prime of life, and they like the trade because of the very high wages paid; but it is difficult to trace the ultimate history of such men, and decide how far the death-rate among men who are picked for their health, strength, and age would give any real information as to the injurious nature of the employment. Here again, as in the case of the furnace man, the temptation to excessive drinking is very great. The bleach packer is more highly paid, and as he has a good deal of responsibility resting upon him in the manufacture of this difficult article, he is a superior man, just as the caustic finisher is a better man than he who works at a furnace door. Many of them are in the local football teams, and I think we may take it that, at any rate for a considerable number of years, working in chlorine does not produce any very obvious bad effects.

Naturally when people first come across this industry, they remark upon the crude methods by which this manufacture is carried on, and they say at once: “Why is not some arrangement invented for the mechanical production of bleach? How easy it would be to put in lime at the one end, and carry it by means of suitable belting out at the other end, and pass the chlorine gas continually over it, and so avoid these unhealthy processes.” And the chemical manufacturer has been denounced for his inhumanity in not adopting some such plan. The question of humanity, or inhumanity, does not enter into the matter. A successful mechanical mode of making bleach would save so much expenditure in labour, the men connected with bleach manufacture being highly paid, and would save so much capital expenditure, that it would be at once adopted by chemical manufacturers. In the Home Office Report on the Chemical Trades, one piece of apparatus, known as the Hasenclever apparatus, is described, and an invention by another engineer. Hasenclever’s apparatus has been used, I believe, in Germany, and there is one works at any rate in St Helens where the apparatus has been tried. I have had no experience of its working, and consequently can say nothing about it, but the mechanical difficulties involved in the manufacture of bleaching powder are so great, that there is no indication at the present time of mechanical methods being adopted. In the case of the Deacon process, shelves are being used, and the latest plant put up by the Alkali Company consists of shelves made of slate, upon which lime is to a certain extent distributed mechanically. In processes where strong gas like the Weldon gas is produced, the lead chamber is still in use, and in modern works where the latest electrolytic plant is being erected in this country, and of which I shall have something to say presently, large lead chambers on the same plan as those used for the Weldon gas are being built. Very little progress has, therefore, been made in the replacing of the old methods of bleach making by a mechanical process. The tendency seems to be in two directions. In the case of the Le Blanc manufacture, with which we have been dealing so far, the Deacon process is replacing the old Weldon process; but in the case of the new electrolytic methods of making bleach, which are probably going to be the methods of the future, the strong gas produced under these conditions is being poured into bleach chambers, built on the old lines.

There is another possible way of getting over the difficulty, and that is by the men wearing a helmet not unlike a diver’s apparatus. There are two difficulties here: one is the awkwardness for the workman wearing such an apparatus, and his dislike to being covered in it, while engaged in heavy toil. Another difficulty is in making the apparatus of such material that it will stand continuous exposure to chlorine gas. It is a common thing for people to say, why not use a helmet covered with gutta-percha, or some other material that will resist chlorine? This sounds very simple, but the material which will continuously resist the action of chlorine, and at the same time will enable us to construct a tight-fitting helmet, with its valves and apparatus, has yet to be discovered. The practical difficulties in the way of improving the conditions of bleach manufacture are very serious indeed, and I fear that no real solution of them has yet been found.

We have still to deal with two other products of manufacture which are made by the Le Blanc process before considering other methods of manufacturing soda and bleaching powder. One of these is sulphuric acid.

The manufacture of sulphuric acid is carried on in many works besides those for the manufacture of soda. Sulphuric acid is used in many processes of manufacture, and is so expensive to carry, that it is found more convenient to make the acid on the spot where it is wanted. The method most universally adopted for making the gas is to burn sulphur or sulphide of iron in specially constructed furnaces, so as to produce sulphur dioxide, with the smell of which we are all familiar. This is drawn into large lead chambers, where it is brought into contact with air, steam, and nitrous fumes. These fumes are produced by decomposing small quantities of sodium nitrate with sulphuric acid, the nitric acid gas and fumes being drawn into the sulphuric acid chambers. In these chambers a chemical reaction is set up which results in the production of sulphuric acid, while the nitrous fumes are regenerated by the action of the air, and are consequently used for the manufacture of a fresh quantity of acid. As it is necessary to cause a current of these gases to move through the chambers, we find at the end of the series of chambers air ladened with nitrous fumes passing away; the nitrous gases are therefore absorbed and are returned to the process again, so that we have in practice the burning of the sulphide of iron going on continuously, and the gases passing into the chambers at the bottom of which the sulphuric acid collects and is drawn off from time to time, while the addition of fresh nitrous fumes, by the decomposition of small quantities of nitrate of soda, is necessary, merely in order to supply the waste which takes place in what is theoretically a continuous process. The manufacture from sulphur dioxide is too new to be considered here.

The men working at the pyrites burners are exposed to heat and cold, and at the same time are exposed to a certain amount of sulphur dioxide, and to occasional nitrous fumes. These gases are, of course, irritating, and must tend to produce similar effects on the breathing apparatus to those found in the case of chlorine and hydrochloric acid. Here again an entirely perfect system would result in the men not having to breathe either sulphur dioxide or nitrous fumes, but under practical conditions of manufacture, such substances are apt to be more or less present on occasion. The work of a pyrites burner is not so arduous as that of a man employed in making salt cake.

The other product of manufacture, introduced in recent years, is that of sulphur. Returning for the moment to the preparation of soda, it will be remembered that at a certain stage black ash was produced, which was treated with water, and the soda it contained dissolved from it. After this operation, the black ash vats are left full of material, known as vat waste, which is principally sulphide of lime. In past years this material was thrown out as a waste product, so that in the neighbourhood of such towns as St Helens immense quantities of it have accumulated, forming great mounds. It is very unsightly, as no vegetation can grow upon it, and it is gradually decomposed by air and rain, with the result that the air and the streams become loaded with sulphuretted hydrogen--a most disagreeable gas--the rotten-egg smell of which is familiar to those who drink sulphur waters. For many years attempts were made to recover the sulphur from this substance, and we now find that the problem has been solved by that part of the Le Blanc manufacture known as Chance’s process.

The tank waste is mixed with a sufficiency of water, and placed in large closed vessels, through which carbonic acid gas is passed. The result is to decompose the tank waste, and give off sulphuretted hydrogen gas, while the carbonate of lime is precipitated. When the decomposition is complete, the sludge is run off from these vessels into a suitable settling pond, and the sulphuretted hydrogen gas, which has been produced, is burned, under certain conditions as to limitation of the quantity of air, with the result that water and sulphur are formed.

This process means the manufacture in enormous quantities of sulphuretted hydrogen, and this gas, as is well known, is very poisonous. Breathing the gas for a few minutes, even if diluted with a considerable quantity of air, results in coma, very often followed by death. The smell of the gas is also so disagreeable, that if only a very little escape, the whole neighbourhood is made intolerable, and therefore the process of manufacture is so carried on as to make the chance of gas escape as remote as possible. At the same time we find here again the difficulty of carrying on a large process with absolute perfection. Consequently, in such a district as St Helens we find that at night the air will, in the neighbourhood of a Chance’s plant, occasionally smell strongly of this gas. The best remedy for gassing with sulphuretted hydrogen seems to be the breathing of pure oxygen, and consequently a cylinder of compressed oxygen is kept at the works. On the other hand, I have not been able to obtain any evidence that the occasional exposure to small quantities of this gas has an injurious effect. People living in the neighbourhood of Chance’s plant are frequently breathing this gas, largely diluted with air, and while they seem at first to suffer in health, loss of appetite, and so on, they seem soon to adjust themselves to it, and not to suffer any permanent inconvenience. At the same time it is very difficult, unless we could have a large number of cases very carefully watched for many years, to tell how far the presence of this gas is deleterious to health in its ultimate effects.

_Alkali Manufacture, other Methods._--We have now dealt with the main branches of alkali manufacture, as carried on by the Le Blanc process, and it remains to say something of the new processes which are being used in connection with this industry. Soda is very largely manufactured in England, and on the Continent, by means of the ammonia soda process. This process is carried on in closed vessels, the substance being in solution during the whole time, and we do not find the furnace introduced until the very last stage, when the soda ash has to be heated at a comparatively low temperature, so that there are no deleterious gases produced. There are no arduous furnace operations, and I have never heard any complaint made as to the conditions of the workmen in this industry. Messrs Brünner, Mond, & Co., the largest manufacturers in this country, introduced some years ago an eight hours’ day for their furnace-workers, and I believe that the result was very successful, but I shall deal with that matter later on.

The ammonia soda process, while giving us soda, does not produce bleaching powder, and consequently we have to adopt some other means of production--either by chlorine, as produced by the Le Blanc process, or by some other method of obtaining this gas. At the works of Messrs Brünner, Mond, & Co., I believe special processes are used by which chlorine is part of the manufacture, but I cannot go further into that particular matter.

One of the most important methods of producing both soda and chlorine, which is now coming to the front, is by means of the electrolysis of salt. An electric current is passed through a solution of salt, and the result is to decompose the salt directly into chlorine gas and caustic soda. The caustic soda can be concentrated, or converted into carbonate of soda, while the chlorine gas is led away and used for the making of bleach. This method of manufacture has been very successful on the Continent, and is also in use in this country, where large new works are being erected for the production of chlorine in this way. As in the case of most new industries, many different devices have been introduced for carrying on the process, some successful and some unsuccessful, but on the whole it continues to advance, and is likely ultimately to replace the Le Blanc process. By this method of manufacture we find all furnace operations are practically done away with; but, on the other hand, the chlorine gas has to be drawn from the decomposing house and converted into bleach, and we find here conditions prevailing which we have already described, and which show no indication of improvement. With the exception of the bleach packing, the conditions of labour, however, are enormously improved, and the more arduous duties of the chemical workers are absent.

We must not expect to see the Le Blanc process of manufacture entirely replaced by these new methods, and for this reason: the first stage of the manufacture consists of the preparation of salt cake as already described. This substance is used in very large quantities in glass manufactories and also in other industries. As long as there is a demand for salt cake, it will probably be prepared by the decomposition of salt with sulphuric acid. It is possible that in the future the Le Blanc process may stop at this stage, and that nothing but salt cake and hydrochloric acid will be manufactured; but salt cake in some way or other must be produced in enormous quantities quite apart from the other products resulting from the Le Blanc process.

_The Chemical Worker._--The general conditions of the chemical worker are very much as I have described them, but how far they affect his health is a more difficult matter. The earlier inquiries into this question seem to have left the effect on health very doubtful. The statistics of the death-rate of such a town as St Helens are not of any value for a purpose of this kind. The town is inhabited very largely by glass workers, coal miners, and engineers, and the chemical workers form only a small proportion of the number of hands employed. I do not find on inquiry of the medical men in St Helens, that they have very definite views on this question. Where we have, for example, lead poisoning produced by an industry, it is very easy to trace back the cause of illness, but when we are dealing with a general undermining of health, it is much more difficult to give definite figures or definite facts as to the effects of an industry. Then the chemical worker changes; he leaves the trade and goes back to it; he moves from place to place. We also find that a very large number of men who work in chemical works are simply labourers employed in the yard, and are only exposed accidentally to the injurious gases produced, and then probably in a diluted form. The construction of the works has also an important effect. We may, for example, be trying to trace the effects on health of employment at the black ash or the salt cake furnace, and in the particular works examined, the bleach chambers might be built in such a position that when the wind is blowing in a certain direction, the chlorine gas is carried to the furnace and may seriously affect the health of the workmen, while in other works the chlorine might be blown in a different direction. The gas is so heavy that under

TYNE AND SCOTLAND DISTRICT.

_Average Hours of Labour and Wages per Week._

+---------------+----------------+----------------+ | | Vitriol | Salt Cake, | | | Burner | Pot, and | |Name of Works. | | Men. | | +------+---------+------+---------+ | |Hours.| Wages. |Hours.| Wages. | +---------------+------+---------+------+---------+ |TYNE:-- | |_s._ _d._| |_s._ _d._| | | | | | | | Allhusen’s | 56 | 32 1 | 56 | 30 0 | | | | | | | | Hebburn | 56 | 33 10 | 70 | 34 6 | | Friar’s Goose| 56 | 31 6 | 71 | 33 0 | | St Bede | 56 | 31 6 | 70 | 32 6 | | | | | | | |SCOTLAND:-- | | | | | | St Rollox | 56 | 35 0 | 70 | 28 0 | | Eglington | 84 | 34 0 | 72 | 38 0 | | Irvine | 84 | 33 3 | 70 | 35 8 | +---------------+------+---------+------+---------+ | Averages | 64 | 33 0 | 68 | 33 1 | +---------------+------+---------+------+---------+