CHAPTER XVII. Description of Processes--_continued_

DESCRIPTION OF PROCESSES--Continued

=Coach-Painting.=--Lead poisoning is peculiarly prevalent in this industry, and no corresponding reduction in the number reported can be observed from year to year (see the table on p. 47), or in the many industries grouped under the heading, “Paint used in Other Industries,” such as is noted for lead industries taken as a whole.

Of the 697 cases included in returns during the ten years 1900-1909, 352 were reported from railway carriage and waggon works, 299 from ordinary carriage works and wheelwrights’ shops, and 46 (separate tabulation was only commenced in 1905) in motor-car works. In the year 1903 inquiry was made in 603 factories and workshops, including all classes of coach and carriage building, railway carriage and engine works, and agricultural implement works. Information was asked (among other things) as to--(1) The number of persons employed in painting with lead paints; (2) description of the method adopted for smoothing the coats of paint; and (3) the substitutes tried for white-lead paint. Persons employed numbered 9,608. In 52 factories and workshops smoothing of the coats of paint was not practised, while in the remaining 551 it was affirmed that a wet method alone (pumicestone and water) was used in 178, a dry method alone (sandpaper) in 39, and both wet and dry methods at some stage or other of the work in 334. Substitutes were mentioned as having been tried in 94 instances, but this was almost exclusively for filling and jointing, and not for the first or priming coat.

The figure 178 (wet method alone) is probably much too high, because, while it is true that pumicestone and water alone are used for the flat surfaces of the body--the bulk of the work--dry sandpapering of the first two priming coats and of the final finishing coats (when of white, cream, or yellow colour), of the under parts of carriages, iron chassis of motor-cars, and of curved surfaces, such as the spokes of wheels, is almost universal. The reason for thus treating the priming coat dry is that a wet process would raise the grain of the wood. The 52 factories in which it was stated that no smoothing was done were nearly all premises for the repair or manufacture of railway trucks, requiring no special finish, and the 39 factories in which only sandpaper was said to be used in smoothing were premises in which rough, cheap, or common vehicles, such as carts, were made. Use of sandpaper is quicker and less expensive than use of pumicestone, and water and wet methods cannot be used very well on iron surfaces.

In ordinary coach and carriage painting, after the sandpapering of the first two priming coats, six or seven coats of “filling” (usually ground slate mixed with gold size and turpentine) are applied, and each coat is rubbed down wet. Joints and interstices of woodwork and irregularities in iron surfaces are generally filled in with a stopping or paste of white lead, in the smoothing of which sandpaper is used.

In the manufacture of motor-cars, the terne (lead) coated sheets which form the body, after preliminary preparation, receive two coats of a lead paint. These are either lightly sandpapered or “flatted” with pumice and water. Three coats of non-poisonous filling follow, and are flatted with pumice or German brick and water. The body then passes to a skilled workman, who applies the final coats of colour. For facing mouldings and for corners throughout all stages of the processes, dry sandpaper takes the place of pumice and water. All stopping on the chassis, the first lead coat on the bonnet, and all coats of paint on the wheels, are sandpapered dry. Sometimes a third of a man’s time may be taken up in sandpapering alone.

Dangers and Prevention.--Grave risk of inhaling lead dust is present (see the table on p. 47) when sandpaper is used, often at a point just above the mouth and nostrils. Rubbing down the wheels is perhaps the most dangerous work, and for this exhaust ventilation can be applied locally. Inventive genius has yet to be directed to some modification of the vacuum-cleaning apparatus, so that an exhaust can be attached to the back of the worker’s hand or in connection with a frame in which the sandpaper is held. In the process of wet rubbing, the abraded coats drip on to the floor, and when dry may rise as dust into the atmosphere.

Precisely similar operations, or only modified in detail, have accounted for heavy incidence of lead poisoning in the painting of perambulators, of safes, of bicycles, of bedsteads, of gas-meters, the “metallic” enamelling of baths (in which also chipping off of the old paint not infrequently occasions an attack), in engineering and machine-making works, in cabinet and furniture making, in French polishing, in the making of artists’ canvases, etc. Several cases are reported among railway employees engaged in the painting of bridges, girders, and signal-posts. A method for the removal of the dust given off in these processes has not yet been arranged. Chipping off of old paint can be effectually replaced by solvent solutions, in the use of which, as they are very inflammable, precautions against naked lights are necessary.

In the making of better-class measuring tapes, the tape, after passage through the white-lead mixture and drying, is made to travel through a machine to remove roughnesses, and subsequently through the fingers of the worker, protected by leather. Dust arises in both the last operations, and requires to be removed by exhaust ventilation. Similar means of prevention are necessary wherever paint is applied, as in photo-engraving, and colouring artificial flowers by means of an aerograph instrument.

Owing to the limited extent to which exhaust ventilation is possible, reliance must be placed on substitution of wet processes for dry wherever possible. Cleanliness of floors requires special attention. Although in all painting operations dust is the most potent cause of poisoning, we would assign to contamination of the hands and the eating of food with unwashed hands a more prominent place as a cause than in any of the other processes involving use of lead or lead colours. In a post-mortem on a sign-painter employed only a few days, made three weeks after his cessation of employment on account of an attack of encephalopathy, paint was found thickly adherent under the nails.

Substitution of colours containing no lead suggests itself as a simple remedy, but the progress in this direction made so far in the industries mentioned is limited. Several important firms manufacturing motor-cars use no lead colours at all; more than one important railway company (the outside of the carriages of which has no white colour) and a few makers of perambulators do the same. It is difficult to obtain knowledge how far leadless are replacing lead colours. In the manufacture of cornice poles (in which small industry several severe attacks were reported) the suggestion of a factory inspector to employ lithopone was adopted, with entire success. A patent graphite has been substituted for orange lead, with which wooden patterns to form the moulds of articles to be subsequently cast in metal are frequently painted.

=House-Painting.=--The work of house-painting and plumbing outside a workshop does not come under the Factory and Workshop Act, 1901, except to a limited extent under Section 105 in buildings in course of erection; and even in that case the requirement of notification of lead poisoning imposed by Section 73 does not apply. If, however, a house-painter is employed for part of his time in mixing paints in a workshop belonging to a builder, then the question may legitimately be raised as to whether plumbism may not have been due in some measure to such workshop conditions. Despite the limited extent to which the Act applies to lead poisoning of house-painters and plumbers, seeing that it is industrial in origin many practitioners notify cases, with the result that the number every year exceeds considerably that from any other lead industry in the country. Thus, the number notified in the ten years 1900-1909 was 1,973, including 383 deaths. The proportion of deaths to persons notified is much higher than for lead industries generally (19·4 per cent., as compared with 4·0 per cent.). If the proportion of cases to deaths were the same in house-painting as in other industries (and it is a fair assumption to make), the number of cases would be 9,418.

When investigation is made into the reported cases, the pre-dominance of the severer symptoms--paralysis, brain symptoms, and chronic plumbism--is brought out. Causation of poisoning, in order of importance, appears to be: (1) Dust from sandpapering one surface of paint before applying another; (2) dust from mixing dry white lead with oil; (3) dust arising from paint that has dried on overalls; (4) contamination of food with unwashed hands; and (5) fumes from burning off old paint.

=Use of Leadless Paints.=--Opinion still differs as to the feasibility of substituting zinc sulphide or zinc oxide (or a combination of the two) for white lead in paints, in spite of elaborate investigation of the point by commissions of inquiry appointed notably by the French, Austrian, and Dutch Governments. There is, however, general consensus of opinion that for the painting of internal surfaces of houses and of all surfaces which are not exposed to the weather zinc paints have the advantage (apart from their non-poisonous quality) over white-lead paint of not changing colour. The technique for applying zinc oxide paint differs much from that for applying white lead. Being much less dense, it requires to be ground with a greater proportion of oil, and the vehicles and driers necessary for the thinning of the stiff paste are different from those ordinarily used for thinning and mixing white lead. Coats of zinc oxide should be applied as thin as possible, and hence there is the drawback that where three coats of white lead will suffice, four coats of zinc oxide may be necessary unless the paint is skilfully applied. The best method of applying zinc oxide paint with the brush has to be learnt in order to get the best effect. The ordinary house-painter, therefore, accustomed to the use of lead paint, cannot expect to obtain the same result from zinc paint treated in the same way. And zinc oxides differ in value as pigments according to the methods of production. That obtained by direct roasting of the ore (franklinite and zincite) is superior to that prepared by the indirect method of oxidation of spelter.

Zinc sulphide enters into the composition of many white paints mixed with zinc oxide, barytes, and often lead sulphate. Its defect in colour is thus concealed, and it adds to the mixture the important property known to the painter as “body.” Under a variety of names, such as “Orr’s enamel white,” “patent zinc white,” and “lithopone,” such mixtures have a large sale, and for many purposes can act as a substitute for white-lead paint.

Extensive inquiries have been made in recent years in Continental countries into the effect of use of white-lead paint in producing plumbism, the processes employed, and the possibility of substitutes--in Austria, from 1904 to 1907; in Germany, in 1905; in Holland, from 1903 to 1909; in France, from 1901 to 1909; in Switzerland, in 1904; and in Belgium, from 1904 to 1909. In 1902 the French Government, by a decree applying to house-painting, prohibited (1) use of white lead except when ready mixed with oil; (2) direct handling of white lead; (3) dry-rubbing or sand-papering of painted surfaces; and required (4) provision of the usual means for cleanliness, including overalls. This decree in 1904 was extended to all kinds of painting with use of white lead. Finally, in 1909, a law, to take effect from 1914, was passed prohibiting the use of white lead in paint altogether.

In Belgium, following on regulations issued under royal decree in 1905, in which, among other things, quarterly periodical medical examination of house-painters was required, the law dated August 20, 1909, came into force, prohibiting the sale, transport, and use, of white lead in the form of powder, lumps, or small pieces, and requiring, if intended for the purpose of painting, the white lead to be mixed ready ground in oil. Dry-rubbing and sandpapering are also prohibited.

In the German Empire the work of house-painting is controlled by regulations dated June 27, 1905, of which the following are the main provisions: (1) Prohibition of actual contact with white lead in grinding and mixing, and adequate protection from the dust so created; (2) mechanical incorporation of the white lead with the oil or varnish, and prevention of the escape of dust into the workroom; (3) preliminary moistening prior to scraping, chipping off, or rubbing down, dry oil colours; (4) and (5) provision of overalls and washing accommodation, including soap, nailbrushes, and towels (in erection of new buildings the workmen must be able to wash in a place free from frost); (7) instruction of the workman by the employer as to the risk attaching to the work by supplying him with a copy of the regulations and cautionary notice. Further, where painting operations are carried on in factories or workshops as subsidiary to other processes, there must be (8) provision of washing accommodation in a special room capable of being heated, and of a place in which to keep clothing; (9) periodical medical examination at half-yearly periods; and (10) prohibition of smoking and consumption of alcohol in the workrooms.

The Austrian Regulations, dated April 15, 1909, follow the German Code closely, but differ in that they (1) prohibit the use of white lead paint for the interior surfaces of houses or of any surfaces not exposed to the weather; (2) affixing of a notice on the can or cask that it contains lead; and (3) periodical medical examination at quarterly instead of half-yearly periods.

At the present time committees appointed by the Home Office are inquiring into the coach-painting and house-painting industries in this country.

The results of careful and detailed experiments made by the White Lead Commission appointed by the Dutch Government, which inquired into the subject, are summarized as follows:

I. Zinc-white paints are much better able to withstand the action of sulphuretted hydrogen gas than white-lead paints.

II. Zinc-white paints do not withstand the action of sulphurous acid in the atmosphere as well as white-lead paints.

As this gas is present in coal-smoke of locomotives, steamers, tall chimneys, etc., zinc-white paint much exposed to such smoke--for instance, in railway-stations, etc.--will soon become corroded, and cannot then replace white lead.

III. Zinc-white paints applied on zinc, Portland cement, or iron (the latter having previously been provided with first coats of red oxide of lead or iron), are able to withstand the action of the open air for a space of five years quite as well as white-lead paints, and can entirely replace the latter, provided they are not exposed to the action of vapours containing sulphurous acid.

IV. In the interior of buildings zinc-white paints, applied on wood, iron, zinc, Portland cement, and plaster, are as good as white-lead paints; and can entirely replace the latter, provided they are not exposed much to vapours containing sulphurous acid or to much damp.

V. Zinc-white paints applied on wood, if not exposed much to the action of sulphurous acid gas, will in many cases last during five years in the open air as well as white-lead paints, and can replace the latter with good results. But in all places where water accumulates, as on window-sills, the lower side of cornice-work, etc., they will, even after three or four years, deteriorate to such a degree that repainting will become necessary for the preservation of the wood; in this respect, therefore, they are inferior to white-lead paints.

VI. Zinc-white paints, such as the White Lead Commission have used successfully, cover at least equally as well as the white-lead paints customary in this country.

The zinc-white putty used by the White Lead Commission is quite as serviceable as ordinary white-lead putty.

VII. Painting with zinc-white paint, such as the Commission used on new woodwork in the open air, does not cost more than painting with the white-lead paints customary for that purpose.

VIII. Painting on existing paintwork, so-called “repainting,” in the open air, with zinc-white paints such as the White Lead Commission used, costs more than the white-lead paints hitherto in use, inasmuch as the preparation of the wood painted with zinc-white paints involves greater expense in rendering it fit for the repainting than in the case of wood painted with white lead in rendering it fit for further painting with white lead.

In the case of painted wood which is exposed to the open air, the possibility is, moreover, not excluded that, where such wood is in an unfavourable condition of humidity (see under § V.), it may have to be repainted sooner than if it had been painted with white-lead paints.

In these circumstances the cost of maintenance of wood painted with zinc-white paint, and exposed to the open air, is further increased as compared with wood painted with white-lead paint.

IX. Lithopone paints cannot replace white-lead paints in the open air; they have proved to be quite unfit in this respect.

X. For paintwork above water, first coats of oxide of iron have, during five years, proved to be quite as good and serviceable as first coats of red oxide of lead.

For coats of paint under water, oxide of iron cannot be used.

Coats of oxide of iron paint are cheaper than coats of red oxide of lead paint.

When oxide of iron is used for the first coat, much more technical skill is required for the painting of the covering coats than is the case when red oxide of lead is used for the first coat.

=Shipbuilding.=--Cases arising in shipbuilding are due not so much to mixing the paints or red-lead paste as to the dust produced in sandpapering the coats of white paint applied in cabins, etc., in chipping and scraping off old red-lead paint, often in confined spaces such as double bottoms, tanks, bilges, etc. Splashing from injecting red lead between plates, fumes from burning off old paint, and fumes from paint while using it in confined spaces, are mentioned in reports. Several attacks have occurred to persons engaged in inserting red-hot rivets into holes containing yarn soaked in red lead and oil. Lead fumes, it is suggested, are given off. The number of cases included under this heading each year has been--

1900 32 1901 28 1902 15 1903 24 1904 48 1905 32 1906 26 1907 22 1908 15 1909 27 1910 21

The figures illustrate the difficulty of obtaining a reduction in the attacks when the cause is to be found in conditions not amenable to control by exhaust ventilation. The possibility of effecting some reduction by such precautions as can be adopted is suggested by the diminution (from 110 to 60) in the number of cases in the Government dockyards in the six years 1905-1910 and 1899-1904 respectively, as compared with the increase (from 67 to 87) in all other shipbuilding yards.

In the Government dockyards, among other precautions, men employed on red-leading appear before the medical officer periodically, and no man is allowed to do the work for more than two days a week. Further, oxide of iron paint is to be used in the double bottoms, wing passages, and other confined spaces on board ships. All men employed as painters are allowed five minutes out of their working time for washing.

=Other Industries.=--The industries and processes which are gathered together under this head will be seen from the following distribution:

Industries. Cases (Ten Years: 1900-1909). (1) Iron drums and kegs 47 (2) Harness furniture 23 (3) Tempering springs 13 (4) Other contact with molten lead 103 (5) Metal sorting 13 (6) Handling lead and dust from metallic lead 122 (7) Shot-making 14 (8) Glass-making 13 (9) India-rubber 23 (10) Yarn-dyeing 28 (11) Copper letters and opal signs 28 (12) Other lead compounds 196 (13) Miscellaneous 36 --- Total 659

(1) and (2) have been described under tinning of metals, as the processes are similar, and in the year 1909 they were included along with tinning of hollow-ware under the same code of regulations.

Tempering of steel buffer springs (3), carried on in Sheffield, gives rise to poisoning from fumes of molten metal into which the springs are immersed, and from dust of skimmings, unless there is efficient hooding and exhaust. A sample of dust collected from a lampshade over a melting-pot was found in the Government laboratory to contain 48·1 of metallic lead, or 51·8 per cent. of lead monoxide. In testing the springs under a hydraulic press, and subsequent straightening by hammering on an anvil, the thin coating of lead on the surface scales off, and may be inhaled.

Other contact with molten metal (4) includes operations which do not differ from several already described, in which danger is incurred from either fumes and dust in skimming the dross or subsequent handling, such as manufacture of solder, coating cables, filling copper cylinders with molten lead for the purpose of bending them, and subsequently re-immersing them in the bath to melt out the lead, tinning of nails, making lead patterns for fenders (in which there may be danger, also, from use of a wire brush to get rid of adhering sand), etc.

Handling lead and dust from metallic lead (5) includes operations such as die-stamping, stamping tickets and other articles on a leaden slab (where the danger is akin to, though probably less in degree than in file-cutting), examining bullets, manufacture of metallic capsules, lining boxes with sheet lead, lead glazing (where the danger is essentially that of plumbing work), etc.

It includes also a number of cases which were reported previous to 1905 in the markers of testing ranges at a small-arms factory. Duckering, who investigated these cases, found that the bullets were stopped by dry sand in boxes 8 feet long. On entering the sand the bullets became disintegrated, so that, after being in use for some time, the sand contained a large amount of lead, and had to be removed. In doing this the box was turned over, and the sand deposited on the floor immediately behind the targets. The lead was then separated by sifting by hand, and the sand used over again. In these operations much floating dust was produced, which was inhaled by the markers, who stood in an open trench immediately in front of and below the targets.

=Metallic Capsules.=--Some cases have occurred from the manufacture of capsules for bottles. The capsule consists of a lead leaf rolled between two leaves of tin. Cases arising in the early processes of casting and rolling do not differ from those described as due to contact with molten metal and handling of lead. The most difficult to deal with are those which occur in the final process of cleaning and colouring. Before colouring with varnish paint, the capsule is placed on a rapidly revolving lathe, and the hand of the worker, carrying a cloth containing whitening, is placed lightly on the capsule. A slight amount of dust is inevitably raised, and this dust, collected from the bench, was found to contain from 11·5 to 25·6 per cent. of lead; while dust which had settled on a beam 9 feet from the floor contained 9·3 per cent. Of thirty-one workers employed in cleaning and colouring, fifteen showed evidence of lead absorption in a blue line on the gums, and in one there was considerable weakness of the left wrist. Similar experience of lead poisoning in this industry has been noted in German and Austrian factories.

Periodical medical examination at quarterly intervals has been instituted in the principal factory, with good results, as it enables those who show early signs of lead absorption to be transferred to other processes. Exhaust ventilation has been tried, but, except at the few lathes where cleaning alone is done, without complete success, in view of the nature of the work.

=Shot-making.=--Cases in shot-making arise from the dust given off when sifting the shot into different sizes--an operation which should be carried on in sieves entirely closed in and under negative pressure. Dust collected from the glass casing over a sifting machine contained 60·3 per cent. of metallic lead. The sample was free from arsenic.

=Heading of Yarn dyed with Chromate of Lead.=--Cotton yarn is dyed (10) on a considerable scale with chromate of lead, chiefly for Oriental markets; and it is the orange chrome--that most heavily weighted with lead--which is most in demand there. The orange chrome colour is obtained by dipping hanks of yarn into solution of lime, and then into acetate of lead. The process is repeated a second time, after which the chromate is formed by dipping in bichromate of soda, and finally boiling in lime-water.

In production of yellow chrome colour, the yarn is treated only once in a bath of lead acetate. Other colours made are lemon chrome and (by addition of an indigo bath) chrome green.

The early processes of dyeing rarely give rise to poisoning, but the strong solution of bichromate of soda readily causes characteristic ulceration of the skin--“chrome holes.” Danger arises from dust in the process of heading or “noddling,” as it is sometimes called, of the dried yarn over posts. The hanks of yarn are tugged and shaken by women as a rule, and in the case of orange chrome very considerable quantities of dust are liberated. We have been told that a hank of this kind of yarn does not commend itself to an Oriental buyer unless, when shaken, dust is visible.

The industry was certified as dangerous in 1895, in view of serious illness and death in Glasgow and Manchester, and special rules were made to apply, not only to the heading operations, but also to the winding, reeling, and weaving, of the dyed yarn--processes in which cases of poisoning are very rare.

Detailed inquiry was made in 1906 in eleven factories where yarn was dyed on a considerable scale by means of chromate of lead--in eight mainly for export to India, and in three for the home market. Yarn dyed for the home market gives off less dust when headed, as the material undergoes additional washing in water and in dilute acid; and it is also sometimes passed through a sizing of starch, which fixes the chromate of lead to the yarn more securely.

Proof of the greater danger from orange chrome is found in the fact that Dupré was able to wash 1 pound of dust (0·29 per cent.) from 345 pounds of heavy orange yarn, and only 1 pound (0·03 per cent.) could be washed from 3,300 pounds of light yellow or green yarn.

In none of the factories were the workers engaged solely on the dangerous yellow and orange chrome-dyed yarn. In some the work may last an hour or two every day, in others for an hour or two every day in alternate weeks, or for one week in every three or four weeks, and perhaps in a dozen factories the work may not be done more frequently than half a day a month, or even one in three months.

Particular attention was paid to the nature of the exhaust ventilation at the “heading” posts, as this is the most important point in the protection of the workers. It was provided in eight out of the nine principal yarn-dyeing factories. The exception was one where the work was said to be solely for the home market. In one a 2 foot 6 inch Blackman fan was placed in the wall without connection of the “heading” posts with it by means of ducts and hoods. In four, hoods and ducts of wood, square in section, with right-angle bends, had been locally applied to the posts. In other four, hoods and ducts were of metal, circular in section. The velocities in feet per minute (obtained with a Davis self-timing anemometer) were taken at the opening into the branch duct behind or under the post. The value of anemometric tests in detecting blockages or interference in the ducts is evident from the table on p. 300.

+----+-----+---------+-----+--------------+----+---------+----+ | | | | | | | | | | (1)| (2) | (3) | (5) | (6) | (7)| (8) |(10)| | | | | | | | | | +----+-----+---------+-----+--------------+----+---------+----+ |Fan.|Fan. |Fan. Fan.| Fan.|Fan. Fan. Fan.|Fan.|Fan. Fan.|Fan.| | 240| 820 | 330 Nil|1,200| 420 450 210| 780| 570 700| 850| | 450| | 450 20| | 420 510 210| | 570 700| | | | | | | | | | | | 480| 270 | 450 270| 780| 360 420 390| 660| 540 490| 850| | 480|(750)| 420 270| | 360 420 430| 540| 570 570| | | | | | | | | | | | 480| 330 | Nil 250| | 270 120 420| 510| 540 530| | | 450|(440)| Nil 300| | 300 120 490| | 540 540| | | | | | | | | | | | 324| 320 | 300 180| | 350 480 450| 300| 300 450| | | 280|(420)| 250 150| | 290 480 420| | 300 450| | | | | | | | | | | | 25| | 130 350| | 430 390 510| | 420| | | 25| | 220 180| | 420 360 460| | 400| | | | | | | | | | | | | | 360 300| | 240 420| | | | | | | 240 280| | 450 480| | | | | | | | | | | | | | | | Nil 210| | 390 | | | | | | | Nil 210| | 390 | | | | | | | | | | | | | | | | Nil| | | | | | | | | Nil| | | | | | +----+-----+---------+-----+--------------+----+---------+----+

(1) The draught here was obtained from the main chimney-shaft. The small velocities at the end post, it was subsequently found, arose from the fact that the double heading post was connected by means of a very small duct to the end of the large duct which served the other posts.

(2) Wooden duct connected up with fan. The area of the openings into the duct could be enlarged or diminished by means of a shutter. The figures in brackets were those obtained when the shutter was fully opened.

(3) In this factory originally a 2 foot 6 inch fan was simply placed in the wall. Subsequently they were boxed in and ducts of wood brought within a foot of the noddling bar. Four of the branch ducts were found to be blocked.

(5) Wooden ducts and hoods behind bar both close to the fan.

(6) Circular metal ducts with curved angles, and placed about 8 to 10 inches behind post; all connected up with a 4 foot 6 inch fan. The small velocities (120 feet) at two posts was due to loose connection of the branch ducts allowing air to be drawn in at the foot.

(7) Metal duct distant about 2¹⁄₂ feet from the post, and situated immediately below and not behind the bar. Dust was prevented from rising above the post by a glass screen, the projection of which also prevented the worker from coming too near to, or getting his head over, the post.

(8) Metal ducts, 9¹⁄₂ inches in diameter. Evidence of ill-health was greatest here, notwithstanding good draught, because the branch ducts were not brought close enough to the point where “heading” was done, but were distant 15 inches from the centre of the post, and “noddling” was done at a distance of 2 feet from the duct, one man standing between the draught and the bar.

(10) Draught arranged as in (7), below the bar, without protection of the worker by a glass screen.

Regulations now apply to the industry. So clear is it that locally-applied exhaust ventilation is of paramount importance in prevention of poisoning, that, however intermittent the operation of “heading,” exemption from this requirement cannot be permitted. Determination periodically by the occupier of the speed of the draught at each exhaust opening should prevent blockage of ducts.

The regulations do not apply to the winding of, and weaving with, yarn dyed with chromate of lead. Rarely in the spinning and weaving factories of Blackburn does the amount of the particular yarn in question constitute as much as 5 per cent. of the total quantity of coloured yarn used. Section 74, 1901, is sufficient to meet the isolated cases where injury to health arises. The habit of biting chrome-dyed thread has given rise to lead poisoning. Nor do the regulations apply to treatment of calico or cloth into which lead may enter. Such poisoning as may occur must be practically confined to persons employed in the paint-mixing house.

=Manufacture of India-rubber.=--Litharge, massicot, red lead, and sulphide of lead, are generally mixed with rubber. Litharge is regarded not only as a valuable filler for rubber, but has the faculty of hastening vulcanization. All dry-heat goods depend upon it where a dark or black effect is wanted.

Every year a few cases are reported in the process of mixing the batches in the weighing room of the rubber factory, or more frequently at the hot calender rolls, where the batch of dry powder containing the lead compound is gradually distributed by hand on to the rubber so as to effect an intimate mixture. The heated air over the rollers causes dust to rise. According to the purpose for which the rubber is wanted, the quantity of litharge in the batch varies. In one factory of fourteen men employed at the calender rolls, ten showed a blue line, five were markedly anæmic, one had weakness of the wrists, and two weakness of grasp. Only one case has been reported since exhaust ventilation was applied locally over each calender roll. In a rubber tyre factory five cases followed one another in quick succession, all in persons employed on the rolls. There should be no hesitation in requiring exhaust ventilation wherever employment in mixing the batches or at the rolls is constant. In general, however, the work in weighing out is intermittent, and reliance is placed on the wearing of a respirator.

No attempt has been made to enumerate all the industries and processes in which lead poisoning may arise. The task would become wearisome, as they are so numerous. Nor is it necessary to give details of all that are known, as it is doubtful whether there can be any different in nature or requiring different treatment from the many which have been described.

REFERENCES.

Special Report on Dangerous or Injurious Processes in the Smelting of Materials containing Lead, and in the Manufacture of Red and Orange Litharge and Flaked Litharge, by E. L. Collis, M.B. Cd. 5152. 1910. Wyman and Sons, Ltd. Price 6d.

Annual Report of the Chief Inspector of Factories for 1901, p. 213.

Ibid., p. 242.

Ibid. for 1906, p. 272.

H. O. HOFMAN: Metallurgy of Lead. 1906.

Annual Report of the Chief Inspector of Factories for 1900, p. 438.

Ibid. for 1910, p. 154.

Special Report above, p. 15.

LAYET: Quoted by Oliver in Dangerous Trades, p. 288.

DIXON MANN: Forensic Medicine and Toxicology, p. 477.

SOMMERFELD: Bekämpfung der Bleigefahr, p. 220.

SOMMERFELD: Quoted by Silberstein below, p. 257.

SILBERSTEIN: Die Krankheiten der Buchdrucker, in Weyl’s Handbuch der Arbeiterkrankheiten, p. 257. Gustav Fischer, Jena, 1908.

TATHAM: Decennial Supplement to Sixty-fifth Annual Report of the Registrar-General. Cd. 2619.

Third Interim Report of the Departmental Committee on Certain Miscellaneous Dangerous Trades. C. 9073. 1898.

Report on the Draft Regulations for File-Cutting by Hand, by Chester Jones. Cd. 1658. 1903.

Annual Report of the Chief Inspector of Factories for 1904, p. 125.

Ibid. for 1906, p. 273.

Special Report on Dangerous or Injurious Processes in the Coating of Metal with Lead or a Mixture of Lead and Tin, by Miss A. M. Anderson, H.M. Principal Lady Inspector of Factories, and T. M. Legge, M.D., H.M. Medical Inspector of Factories; together with a Report on an Experimental Investigation into the Conditions of Work in Tinning Workshops, and Appendices, by G. Elmhirst Duckering, one of H.M. Inspectors of Factories. Cd. 3793. London: Wyman and Sons, 1907.

Annual Report of the Chief Inspector of Factories for 1902, pp. 296-318.

Report on Draft Regulations on the Tinning of Metal Articles, by E. T. H. Lawes.

The Cause of Lead Poisoning in the Tinning of Metals, by G. E. Duckering.

The Health of Brass Workers, by T. M. Legge. Annual Report of the Chief Inspector of Factories for 1905, pp. 388-397.

Ibid. for 1898, pp. 119-123; and many references in later Annual Reports.

The Bischof Process for the Manufacture of White Lead, by Professor Sir William Ramsay, K.C.B., D.Sc. 1906.

Report of the Departmental Committee on the Use of Lead, and the Danger or Injury to Health arising from Dust and Other Causes in the Manufacture of Earthenware and China: vol. i., Report; vol. ii., Appendices. Cd. 5277-8. 1910.

Lead Compounds in Pottery: Report to H.M. Principal Secretary of State for the Home Department on the Employment of Compounds of Lead in the Manufacture of Pottery; their Influence upon the Health of the Workpeople; with Suggestions as to the Means which might be adopted to Counteract their Evil Effects, by Professor T. E. Thorpe, LL.D., F.R.S., Principal of the Government Laboratory; and Professor Thomas Oliver, M.D., F.R.C.P., Physician to the Royal Infirmary, Newcastle-on-Tyne. London: Eyre and Spottiswoode, February, 1899. Price 5¹⁄₂d.

Work of the Government Laboratory on the Question of the Employment of Lead Compounds in Pottery, by Professor T. E. Thorpe. Cd. 679. 1901.

H. R. Rogers: Report of a Series of Experiments for Determining the Amount of Lead in the Glaze of Finished Ware, based on the Method described by Sir Henry Cunynghame, K.C.B., in his evidence before the Departmental Committee on the Use of Lead (see 22, above).

See 22, above, pp. 93, 94.

C. R. PENDOCK: Unpublished Report.

Special Report on Dangerous and Injurious Processes in the Enamelling and Tinning of Metals, by Miss A. M. Anderson and T. M. Legge, in Annual Report of the Chief Inspector of Factories for 1902, pp. 296-318.

Annual Report of the Chief Inspector of Factories for 1910, p. 154.

Zeitschrift für Gewerbehygiene, Unfall Verhütung und Arbeiter-Wohlfahrtseinrichtungen, January, 1902.

Annual Report of the Chief Inspector of Factories for 1901, pp. 221-229.

Die in electrischen Akkumulatoren Fabriken beobachteten Gesundheitsschädigungen. Arbeiten aus dem Kaiserlichen Gesundheitsamte, by Dr. Wutzdorff. 1898.

Third Interim Report of the Departmental Committee appointed to inquire into and report upon Certain Miscellaneous Dangerous Trades, pp. 16-19. C. 9073. 1898.

D’ARCY ELLIS: Brit. Med. Journ., vol. ii., pp. 406-408, 1901.

Report on the Manufacture of Paints and Colours containing Lead, as affecting the Health of the Operatives employed, by T. M. Legge, M.D. Cd. 2466. 1905.

Painters’ Colours, Oils, and Varnishes, by G. H. Hunt, Griffin, p. 357. 1901.

Annual Report of the Chief Inspector of Factories for 1905, pp. 366-368, and references in other Annual Reports.

Report of the Departmental Committee appointed to inquire into the Dangers attendant on Building Operations, Appendix IX., pp. 184-187. Cd. 3848. 1907.

Painters’ Colours, Oils, and Varnishes, by G. H. Hunt, Griffin. 1901.

Annual Report of the Chief Inspector of Factories for 1910, pp. 175-176.

Ibid. for 1906, pp. 272, 273.

Annual Report of the Chief Inspector of Factories for 1905, pp. 368, 369.

Dangerous Trades Committee’s Final Report, C. 9509, pp. 26-30.

ALEX. SCOTT: Minutes of Evidence of Various Lead Industries Committee, 1894, C. 7239-1, pp. 105-108.

J. S. CLAYTON: Industrial Lead Poisoning among Yarn Workers. Brit. Med. Journ., vol. i., p. 310, 1906.

Annual Report of the Chief Inspector of Factories for 1901, p. 231.

INDEX

Abortion caused by lead, 35

Absorption of lead: cutaneous, 25; from lung, 23; gastric, 19; intestinal, 21, 22; in liver, 24; mechanism of, 20; prevention of, from stomach, 23

Accumulators. See Electric accumulators

Acetate of lead, poisoning by, 94

Acetic acid, solvent action of, on lead oxide, 15

Acid lemonade, 185

Acidity, gastric contents, 15

Action of lead: on gold and silver, 3; on water, 3

Acute encephalopathy, 54, 95

Acute lead poisoning, 110, 111

Acute nephritis, 60, 131

Aerographing, 272, 280

Ætiology of lead poisoning, 7

Age as affecting lead poisoning, 35, 239

Akremnin soap, 238

Albuminate of lead, preparation of, 17

Albuminuria, 128

Albuminuric retinitis, 160

Alcohol: as predisposing cause, 37, 64; gastritis and plumbism, 64; in experimental poisoning, 85; similar effect to lead on kidney, 131

Alteration in blood-corpuscles in lead anæmia, 133

Alternation of employment, 34, 251

Amaurosis, 70, 160

Amblyopia, 76

Amenorrhœa, 36

Anæmia, 39, 112, 132, 136, 227; treatment of, 190

Anemometers, 219

Antibrachial paralysis, 144, 148

Antimony, effect of, on lead fume, 199

Appointed surgeon, 112, 221

Aran-Duchenne paralysis, 149

Armit, nickel poisoning, 11

Arsenic: Cloetta’s experiments, 24; excretion of, in fæces, 24

Arterio-sclerosis, 116

Arthralgia, 50, 161

Arthritis, 40

Artificial gastric juice, action of, 17

Atrophic nerve changes, 69

Attack rate from lead poisoning (table), 55

Autopsy, points to be noted in, 162

Bacup epidemic, 4

Basophile granules, 77, 133, 135, 179

Baths, 238

Blood: action of lead salts on, 2; in lead poisoning, 70, 78, 134, 179; pressure, 116, 180; vessels, 68, 70, 75

Blue line, 122, 123, 128, 226; experimental production of, 41, 124; from diachylon, 13

Brachial paralysis, 148

Brain, analysis of, 96

Brass, presence of lead in, 263

Brassworkers and plumbism, 51, 263

Breathing experiments, 81

Bright’s disease and lead poisoning, 60

Burtonian line. See Blue line

Carbon in lung, 11

Card system, use of, 186

Central nervous system, 69, 157; treatment, 196

Cerebral symptoms, 51, 157

Certifying surgeons, reports of, 45, 221

Chandelier fitters, poisoning among, 264

Channels of lead absorption, 8

Chemical analysis of brain, 95

Chemical characters of lead salts, 4

Chemical diagnosis, 166

Chemical examination of organs, 163

Chemistry of lead, 2

Choroidal atrophy, 161

Chromate of lead in yarn-dyeing, 298

Chrome colours, 287

Chronic colic, 119

Circulatory system, 75, 137

Cirrhosis of kidney, 74

Coach-painting, 288; dust in atmosphere breathed, 205; leadless paints, 290; reported cases from, 289; sandpapering in, 289

Colic, 116, 117, 118, 119, 188, 190; differential diagnosis, 188; treatment of, 187

Colloidal lead, 5

Colon, palpation of, 126

Colours, 285

Comparative mortality, 59

Conjunctiva in lead anæmia, 132

Constipation, 115

Copper extraction, plumbism in, 246

Cutaneous absorption, 25

Death certificates in plumbism, 57

Degeneration of blood vessels, 68

Determination of lead in urine, 169

Diachylon, 13

Diagnosis: from chemical analysis, 166; of lead colic, 120, 188

Diarrhœa, 115

Differential count in lead anæmia, 134, 137, 180

Digestion experiments, 16, 17

Drink for lead-workers, 186

Drugs in lead colic, 189

Duration of employment and plumbism, 52

Dust, lead: amount of, in air breathed, 199, 207; chief cause of plumbism, 10; “laying,” difficulties of, 11; rate of settling, 7; respirators for, 207

Dysmenorrhœa, 36

Earthenware: and china, 270; attack rate, 56; decorative processes, 272; dust in atmosphere, 204, 206; glaze processes, 272; leadless glaze, 274; low solubility glaze, 274; Potteries Committee on, recommendations of, 275; reported cases in (table), 271

Electric accumulators, 281; reported plumbism in, 283; ventilation in, 216

Electrical reactions, 151, 153, 154

Electrical treatment, 194

Electro-chemical tests, 168

Electrolytic estimation of lead, 174; reactions, 5

Enamelling (vitreous), 278; aerographing in, 280; use of leadless colours in, 278

Encephalitis, case of chronic, 71

Encephalopathy, 54, 68, 71, 157

Estimation of lead: in digestion, difficulties of, 18; in urine, 169, 170, 175

Excretion: of arsenic, 24; of lead salts, 32, 127, 128

Excretory system, 72

Exhaust ventilation. See Ventilation

Experimental lead poisoning: pathology of, 81; post-mortem findings, 91; symptoms, 69, 89, 103

Experimental arsenic poisoning, 24

Experimental results, summary, 104

Eye changes, 76, 150, 158

Facial nerve, paralysis of, 195

Fæces: examination for lead in, 182; lead in, 32, 64

Family susceptibility, 30

Fans. See Ventilation

Faradism for paralysis, 195

File-cutting, 256; atrophy of muscles in, 52, 257; reported cases in, 258

File-hardening, 258; lead fume from, 200, 201; use of fused metallic salts for, 258

Forms of paralysis, 54, 142

Fritted lead: action of water on, 89; poisoning, 34, 97; solubility test, 14

Fume (lead) in atmosphere breathed, 198, 207

Gastric absorption, 19, 21, 22

Gastric digestion, artificial, 17

Gastric juice, action on lead salts, 15, 16

Gastritis in plumbism, 65

Gastro-intestinal absorption, 12, 13, 64

Generalized paralysis, 151

Glass-cutting, 283

Glaze, 272; leadless, 274; low solubility, 274

Gout, 38

Hæmatoporphyrin, 180, 182

Hæmoglobin, 113, 132

Hæmorrhages in plumbism, 76

Hæmostatic action of lead salts, 2

Hair lotions, poisoning from, 13

Harness furniture, tinning of, 259

Headache, 120

Health Register, 228

Heart, 139, 193

Heart symptoms, 193

Heat, exhaust by, 208

Histological examination of lead tissues, 163, 176

Histology: of experimental poisoning, 92; of nervous system, 67

House-painting, 291; regulations for, 293; reported plumbism in, 291

Hunter, John, “dry bellyache” from rum, 1

Hyperæsthesia, 161

Immunity, 27, 29, 113

Incipient symptoms, 112, 222

India-rubber, manufacture of, 301

Inhalation experiments (table), 101

Inoculation experiments, 83, 88, 99

Instruction of worker, 240

Interstitial nephritis, 130

Intestinal absorption, 22, 94

Intestinal staining, 21, 94, 125

Iodine in plumbism, 192

Ionization in paralysis, 195

Iron drums, tinning of, 260

Italians and lead poisoning, 30

Kidney: changes, 73, 74, 129; excretion of lead by, 128; interstitial hæmorrhages, 130

Lactic acid, solvent action of, 15

Large intestine and lead absorption, 21

Lavatories, 235, 238

Lead: compounds, 7; fume and dust in atmosphere, 198-207; in urine, 129, 167; melting-point, 2, 199

Lead bed in file-cutting, 257

Lead burning, 262; in electric accumulators, 283

Lead chloride in tinning, 200

Lead dust: minimal toxic dose, 31, 207; rate of settling, 7; size of particles, 12

Lead fume in tinning, 202

Lead oxide, danger from skimming, 200

Lead piping, 251

Lead poisoning: acute, 110; mortality, 57; entry of poison, 8

Lead silicate, 34

Lead smelting: and silver refining, 242; analysis of fumes in, 246; cupellation process, 246; Huntingdon-Heberlein process, 243; in blast furnace, 243; Parkes’s process, 244; Pattinson process, 245; reported plumbism, 248

Leadless glaze, 274

Leadless paints, 291

Lead salts: action on blood, 2; action of gastric juice on, 16, 17

Lemonade, sulphuric acid, 185

Letterpress printing. See Printing

Litharge, manufacture of, 250

Lithopone, 291, 292

Litho-transfers, 277

Liver, absorption by, 24

Loss of fat in plumbism, 112

Lumbago, 115, 192

Lung: absorption by, 98; phagocytic absorption of lead, 23

Meal-rooms, requirements of, 234

Mechanism of lead absorption, 20

Medical examination, periodical, 115, 221-229

Medical Health Register, 228

Medical practitioners and notification, 44

Melting-point of lead, 2, 199

Menorrhagia, 36

Mental symptoms, 114, 121, 158

Metallic capsules, 297

Metallic taste, 127

Micro-chemical tests, 167

Molten lead, contact with, 297

Mortality figures, 59

Motor-cars. See Coach-painting

Muscles paralyzed in experimental poisoning, 144

Muscular system, affections of, 114-161

Nephritis, 192

Nervous symptoms, 66, 67, 140; treatment, 193

Neuritis, peripheral, 66, 67

Nickel carbonyl poisoning via lung, 11

Normal lead, 33

Notification of plumbism, 44

Œdema of brain, 159

Olive oil in colic, 189

Ophthalmoscopic examination, 160

Oral sepsis, 38

Orange chrome, 299

Organic mixtures, lead in, 173

Organic compounds of lead, 5

Organs of generation, effect on, 36

Overalls and head coverings, 230

Oxides of lead, 3, 249

Painters and lead poisoning, 107. See also House-painting

Paints: and colours, manufacture of, 285; leadless, 29, 291

Pancreatic digestion, action of, 17

Paralysis: in animals, 14; electrical reactions in, 181; forms of, 64, 66, 142; general, 151; in file-cutters, 152; insidious onset of, 114; of special sense organs, 150; prognosis of, 197; statistics of, 53

Parotitis, 127

Pathology of lead poisoning, 62

“Pentarcomb” exhaust, 217, 254

Peptonate of lead, 18

Peptone, solvent action of, 19

Perambulators, painting of, 290

Perihepatitis, 264

Peripheral neuritis, 266

Peritonitis, saturnine, 65

Peroneal paralysis, 149

Phagocytosis of lead particles, 20

Phthisis: in printing, 256; not a sequela, 60

Physiology of digestion, 16

Plumbing, 261

Plumbism, reported cases (1900-1909), 46, 47

Plumbo-solvency of water, 4

Porcelain enamelling, 278

Post-mortem signs, 91, 161

Potassium iodide, action of, 32, 191

Pottery. See Earthenware

Predisposing causes, 36, 42

Presaturnine state, 184

Preventive measures: age of employment, 239; baths, 238; cloakroom, 231; exhaust ventilation, 207; floors, 240; food, 86; head coverings, 231; instruction of worker, 240; meal-room, 234; overalls, 230; periodical examination, 221; separation of processes, 239; washing accommodation, 235

Printing: compositors’ work, 255; linotype machine, 200, 211, 217, 253; reported cases from, 252; stereo-casting, 254; type-casting, 252

Prodromal symptoms: of colic, 118; of paralysis, 141

Prognosis in lead poisoning, 197

Progressive spinal muscular atrophy, 68

Pulse-rate, alteration of, 76, 115, 118

Purgatives in lead colic, 188

Putty powder, 283

Pyorrhœa alveolaris as predisposing cause, 40, 124

Qualitative tests, 166

Quantitative estimation of lead, 170

Reactions of degeneration, 152

Red lead: manufacture of, 249; reported attacks in, 249

Relative toxic dose of lead compounds, 105

Repairs in factory as cause of plumbism, 10

Respirators, inefficiency of, 217

Respiratory absorption, 9

Rheumatic pains, 121, 161, 192

Safes, painting of, 290

Salivary glands and excretion of lead, 125

“Selective” action of lead on nerves, 147

Sequelæ of lead poisoning, 57, 60

Sex as affecting susceptibility, 35

Sheet lead, 241

Shipbuilding, 295; reported plumbism, 295

Shot-making, 298

Silicates of lead, 34

Silver refining. See Lead smelting

Size of particles of lead compounds, 12, 34

Skin, colour of, 132

Smelting of lead. See Lead smelting

Solar plexus, 65

Soldering, 261

Solubility: of lead salts, 5, 15, 16, 17; test for fritted lead, 14

Solvent action of peptone, 19

Spastic paraplegia, 68

Spiegeleisen, poisoning in manufacture of, 246

Spring tempering, fume from, 201, 296

Stained-glass painting, 285

Statistics of plumbism, 44, 45

Susceptibility, 27

Tape measures, painting of, 290

Tea lead, 251

Temperature in lead poisoning, 118

Tempering files, 200

Terne plates, 260

Tests for lead, 167

Tetramethyl diphenyl test, 169

Thorpe test, 275

Tiles. See Earthenware

Tinning: of hollow-ware, 259; of harness furniture, 259; of irondrums, 260; dust in, 203; lead chloride fume in, 202-203; repeated attacks in, 261

Tolerance of lead, 28, 113

Toxic dose: of lead acetate, 110; of lead carbonate, 110; of lead dust, 31, 207; of fritted lead dust, 88, 97; of white-lead dust, 85

Treatment of acute lead poisoning, 111, 184

Tremor, 142, 156

Turpentine poisoning, experimental, 108

Type metal, 202

Urine: acidity, 181; chemical examination of, 180; determination of lead in, 167; lead in, 32, 73, 169; phosphates, 181

Vaso-motor changes, 65, 76, 140

Ventilation (exhaust), 207-220; by fans, 210; by heat, 208; composing boxes, 255; essential points, 208; in earthenware, 273; in electric accumulators, 216, 282; in enamelling, 278; in glass-cutting, 284; in india-rubber, 302; in lead smelting, 245; in litharge, 251; in paints, 215, 286; in printing foundry, 254; in red lead, 250; in spelter, 249; in tinning, 259; in vacuum cleaning, 218; in white lead, 214, 268; in yarn-heading, 300; smoke-test, 218

Volatility of lead, 2

Washing accommodation, 235

Wasting in lead poisoning, 113, 115, 145

Water, action on lead, 3, 4

White lead: Brimsdown process, 269; casual labour in, 269; cause of dangers in, 266; chamber process, 268; diminution in reported cases, 270; Dutch process, 265; precipitation process, 269; ventilation in, 214

Works’ medicines, 185

Wrist-drop. See Paralysis

Yarn-dyeing with chromate of lead, 298

Zinc: action on kidney, 130; paints, 292, 294

BILLING AND SONS, LTD., PRINTERS, GUILDFORD

Transcriber’s Notes

The text used in this document is the one used in the source document, except as mentioned below. In particular, non-English words and phrases and titles and author names of references, and summations and other calculations in tables have not been corrected, unless mentioned below. Table numbering (or the lack thereof) has not been standardised.

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Page 1, 6: Stockhusen is probably an error for Stockhausen.

Page 38, the reference to Goadby points to a publication by Garrod.

Page 52: hyperthenar eminence may be an error for hypothenar eminence.

Page 64, ... se recontrant d’une manière diffuse ...: possibly an error for ... se rencontrant d’une manière diffuse ....

Page 70, bottom row of Table IX: possibly the first column should read Average age at death.

Page 220, Literature reference : there is no footnote marker in the text.

Changes made

Tables and illustrations have been moved out of text paragraphs. Some of the tables have been re-arranged or split for legibility; ditto marks and the word Ditto have in several places been replaced with the dittoed text.

Some obvious minor typographical and punctuation errors have been corrected silently.

Page 3: ... mascicot and litharge ... changed to ... massicot and litharge ....

Page 47, Table III bottom part: value for 1911 in the row Other industries changed from 8 to 88⁴ (based on the totals given).

Page 61, Footnote : Dr. John Tathan changed to Dr. John Tatham.

Page 75: Pfleuger changed to Pflueger.

Page 76: Seiffert changed to Seifert.

Page 79, references and : Bleilähnung changed to Bleilähmung; reference : les Maladies du Pois et Reins changed to les Maladies du Foie et des Reins.

Page 88: eutetic entangling changed to eutectic entangling.

Page 137: The footnote under second table (Furniture-Makers--Sand-Paperers) has been copied to under the first table (on Lead Sulphate Workers) for clarity.

Page 151: Electrical Reactions. changed to =Electrical Reactions.=

Page 169: magnese changed to manganese.

Page 220: Leclere de Pulligny changed to Leclerc de Pulligny.