to the prohibition of eating within the factory; cleanliness of floors, walls, and ceilings; providing running hot water, soap, and individual towels; installing exhaust. systems to dispose of the dust created in the process of manufacture; suitable place in which to eat meals; and suitable means to remove dust from the floors.

Analytical determinations.—A chemical analysis was made of air of one of the packing rooms, where filling of boxes from barrels was performed; 305 milligrams of the paris green were found per cubic meter of air at 60° F. This material in the air was generated in the process of hand filling, blown off the walls and ceiling, and stirred up from the floor in the act of walking. A proper method of weighing and filling under inclosed hoods, clean walls, and floors would have eliminated this large amount of dust.

Samples of underclothing were analyzed and found to contain 1.1 milligrams of paris green in a piece measuring six square inches.

Printed notices furnished by the Department of Labor of the State Industrial Commission, to read as follows, should be posted in every room where paris green is handled:

"Paris green is a dangerous poison and sickness results from the breathing of air containing it, through broken skin, and through the mouth.

"Don't hang any clothes to be dried in the dry room.

"Don't leave the factory in the clothes in which you work.

"Don't place your factory clothes in the same locker with street clothes, when provided for you.

"Don't eat in or about the factory, only in provided lunch room.

"Don't eat before you have washed your face and hands with hot water and soap.

"Don't scratch or touch any part of your body before you have washed your hands.

"Don't sweep the floor with a broom.

"Don't plug your nose with cotton; tie clean cotton waste over nose and mouth.

"Keep your gloves clean on the inside.

"Take a complete wash at home daily.
"Drink milk instead of beer or whiskey.

"Tie clean cotton waste, twice daily, over nose and mouth, as this is the easiest and best respirator.

"Try and keep down dust as much as possible by closing doors carefully and keeping the dust off the floor as much as possible.

"Keep your hair, mustache, and finger nails short, to prevent the paris green from settling in them."

Recommendations to employer.-Provide double lockers for men engaged in paris green manufacture.

Sweep all floors and keep ceiling and walls of workroom, halls, stairs, and lunch room free from paris green dust by using a vacuum sweeper.

Provide periodical medical examinations for men engaged in the production of paris green and Scheele's green.

Provide overalls, head and neck pieces of unbleached muslin, and gloves for paris green workers, and have same washed weekly.

Provide clean cotton waste as respirators for all paris green workers.
Not less than one hour should be permitted for the noonday meal.

It is suggested to the State industrial commission that the recommendations which are made and are not covered by law be enacted into a code in order that this industry be freed from the many dangerous conditions which now surround it.

DANGERS OF THE AIRPLANE INDUSTRY FROM A HYGIENIC

STANDPOINT.

The report of an inquiry recently made under the direction of the New York State Industrial Commission into the dangers of the airplane industry from a hygienic standpoint, is summarized in the June, 1917, bulletin of the Industrial Commission (pp. 185 to 189). This report is based on studies made in eight factories in New York State, whose products are airplanes and hydroplanes, in three of which some thought appears to have been given to insure safety and to protect the health of the men engaged in the dangerous processes connected with the manufacture of these articles. "In the other five factories no attention has been paid to these safety details, and it became evident that these conditions must be remedied at the earliest possible moment."

Attention has been called in the MONTHLY REVIEW to the danger point connected with this industry,1 namely, the "doping" of airplane and hydroplane wings, ailerons, rudders, and fuselage. This "dope" contains chiefly as its base either acetate or nitrate of cellulose mixed with a solvent which, when applied, quickly evaporates and leaves the base of acetate or nitrate of cellulose firmly fixed within the interstices of the linen. In the early days of the industry tetrachlorethane was supposed to be the one solvent which rendered the linen most taut. A chemical analysis was made of the various "dopes" used in the New York factories to determine the solvents employed, and it was found that each of seven samples contained one or more of the following solvents: Tetrachlorethane, alcohol, acetone, benzol, acetic acid, amyl acetate, and fusel oil. It is the usual custom, according to this report, for seven coats of the "dope varnish" to be applied, the first five coats being acetate of cellulose "dope,” - while the last two are of a nitrate "dope." From 30 to 45 minutes are allowed between each coat. The parts doped are then placed on racks and allowed to dry in close proximity to the workers. Since speed in manufacture is now an important consideration, the drying of the varnish is hastened by keeping the "dope" rooms at a much higher temperature than other parts of the factory, thus intensifying the discomfort of the employees.

The report recites the conditions found in each factory, noting specific cases of employees affected by the poison, and submits the following recommendations:

1. In aeroplane factories where "dope" is used a downward system of ventilation should be furnished; intakes to be located at floor level, which should be situated about 6 feet apart beneath working areas.

1 See MONTHLY REVIEW for June, 1916, p. 86; November, 1916, pp. 649-652; January, 1917, pp. 97 and 98.

2. Drying of wings, ailerons, and rudders to be done in a room separate and apart from the "dope

room.

doped" it should be done in proximity to a downward

4. Each morning and afternoon should be interrupted by a 15-minute rest period, men to go into the open air during such times.

5. Hot running water, soap, and individual towels, also overalls, should be provided for all "dope" workers.

6. Lockers, which shall be well ventilated, should be provided for all "dope" workers.

7. No eating should be permitted in any "dope" room.

8. Not less than one hour shall be allowed as a lunch period to any worker engaged in the process of "doping."

9. Active medical supervision, as an early diagnosis of "dope" poisoning prevents serious after effects.

10. No "doping" should be conducted in the open air unless the same is done under a shed so as to prevent rapid evaporation of the poisonous fumes.

11. Any workers, who complain of dizziness or sleepiness, should be immediately removed from the work for 48 hours.

INJURIOUS DUSTS IN STEEL WORKS.1

In a pamphlet on "Occurrence and mitigation of injurious dusts in steel works," issued by the United States Bureau of Mines, the author makes the statement that from the standpoint of the industrial hygienist no health hazard to which those employed in modern industries are exposed is of greater importance than that of a dustladen atmosphere. This dust may act injuriously, it is stated, in three different ways, depending on the character of the dust particles: (1) by irritant action, (2) by toxic action, and (3) by mechanical action. Sometimes the dust may act in two or more of these ways simultaneously. The paper notes briefly the different places in a steel plant where dusts of various kinds may be encountered, and gives the result of air sampling at working places in order to determine the extent to which the dusts were suspended in the atmosphere. The largest quantity of dust per 100 liters (3.53 cu. ft.) of air was found in ore bins, ranging from 3.04 milligrams to 44.2 milligrams (0.05 to 0.68 grain), and in dolomite sheds, ranging from 5.5 milligrams to 33.4 milligrams (0.08 to 0.52 grain).

How the dust may be abated in the various departments of a steel plant is suggested in some detail, but the general statement is made that the dust hazard may be mitigated by preventing dust suspension, by removing suspended dust from the air, and by providing against the inhalation of dust. To prevent suspension it may be necessary

1 United States. Department of the Interior. Bureau of Mines. Technical Paper 153, Occurrence and mitigation of injurious dusts in steel works, by J. A. Watkins. Washington, 1917. 20 pp.

to alter the usual procedure of the manufacturing processes or to change machinery or equipment in order to obtain satisfactory results. In some cases sprinkling with water may prove effective. To remove suspended dust from the air, an efficient system of exhaust and of supplying air is recommended. The prevention of inhalation of dust may be secured by requiring the employees to wear respirators or by altering their duties and places of work.

GLASSES FOR PROTECTING THE EYES FROM INJURIOUS
RADIATIONS.1

Owing to the incidence of eye injuries in some manufacturing processes, particularly those involving prolonged exposure to intense heat from furnaces containing molten metal, glass, etc., considerable attention is being given to determining the best means for protecting the eyes from these radiations. To this end the United States Bureau of Standards has recently issued a pamphlet 2 intended to meet the demand for general information concerning the protective properties of spectacle glasses, particularly glasses which shield the eyes from infra-red or so-called heat rays. While no definite proof of the injurious effect of infra-red rays from incandescent bodies, such as molten metal, is available, there appears to be a general feeling that the eye becomes fatigued, if not permanently injured, under conditions which expose the worker to these heat rays. The fact is noted that no artificial source of light used for illuminating purposes contains enough ultra-violet radiation to be injurious to the eye, under practical working conditions, while the infra-red rays have no specific action distinct from thermal effect, but that in view of the fact that the infra-red rays are in far greater abundance than the ultraviolet, the inference is that glassworker's cataract is to be ascribed to the heat rays rather than to the ultra-violet rays. It is noted that exposure to excess of ultra-violet light is injurious, causing conjunctivitis.

Tests have been made to show that most of the energy (97 per cent) radiated from a furnace at 1,000° to 1,200° C. (1,832° to 2,192° F.) is absorbed in the outer portion of the eye and that injuries caused by infra-red rays therefore must occur in that portion, while, on the

1 An annotated list of references to books and periodicals on eye injuries and diseases, with special reference to eyestrain, appears on pages 186 to 191 of this issue of the MONTHLY REVIEW.

2 United States. Department of Commerce. Bureau of Standards. Technological paper, No. 93. Glasses for protecting the eyes from injurious radiations, by W. W. Coblentz, associate physicist, and W. B. Emerson, laboratory assistant. Washington, May 5, 1917.

14 pp.

other hand, the eye is quite transparent to ultra-violet rays, some wave lengths of which can reach the retina.

Moreover, the physiological effect seems to be different. The infra-red rays appear to produce a thermal effect ("burns "), while the ultra-violet rays (although of a much lower energy value) seem to attack the tissue in a different manner, i. e., their effect is actinic.

To meet these conditions, it is stated, numerous glasses have been produced which differ from the ordinary white crown glass used in spectacles in having a high absorption (1) of the violet, (2) of the infra-red, or (3) of both the violet and infra-red. These glasses differ in the amount and color of the light transmitted.

Glasses having a gray or neutral tint are the most agreeable to wear, as they do not alter the color of objects. Hence, for outdoor wear ordinary black glasses, which can be obtained for a few cents, are quite as good as the expensive glasses which one frequently sees advertised.

The report discusses the protective properties of various glasses, with particular reference to their absorption of the infra-red, and tabulates a summary of the most important glasses investigated showing the maximum transmission in the visible spectrum and the per cent transmitted of the total radiation from a furnace heated to 1,000° to 1,100° C. (1,832° to 2,012° F.). The data collected from these investigations, representing an extensive group of glasses available for protecting the eye from the ultra-violet, the visible, and the infra-red rays, led to the following conclusions:

For protecting the eye from ultra-violet light, black, amber, green, greenishyellow, and red glasses are efficient. Spectacles made of white crown glass afford some protection from the extreme ultra-violet rays which come from mercury-in-quartz lamps and from electric arcs between iron, copper, or carbon. The vapors from these arcs emit but little infra-red radiation in comparison with the amount emitted in the visible and in the ultra-violet.

For shielding the eye from infra-red rays deep black, yellowish-green, sage-green, gold-plated, and bluish-green glasses are the most serviceable. For working near furnaces of molten iron or glass if considerable light is needed a light bluish-green or sage-green glass is efficient in obstructing the infra-red rays. For working molten quartz, operating oxyacetylene or electric welding apparatus, searchlights, or other intense sources of light, it is important to wear the darkest glasses one can use, whether black, green (including gold-plated glasses), or yellowish-green, in order to obstruct not only the infra-red but also the visible and the ultra-violet rays.

Data are given showing that of the infra-red rays emitted by a furnace heated to 1,000° to 1,100° C. (1,832° to 2,012° F.) (1) about 99 per cent are obstructed by gold-plated glasses, (2) about 95 per cent by sage-green or bluishgreen glasses, (3) about 60 to 80 per cent by very deep black glasses, and (4) about 60 per cent by greenish-yellow glasses.

At higher temperatures these data would be somewhat different, but not sufficiently so to modify the rough estimates dealt with in this paper,