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as the burning point, e.g., 3 per cent petroleum ether lowered the flash point 93.6 deg. and the burning point only 46.8 degrees.

The burning point curves are of about the same shape as the open cup flash point curves, showing that in the case of the high and low test gasoline-kerosene mixtures the burning points did not decrease at the same rate as each other. In making up mixtures, the order of addition did not affect results, though such a difference is possible for a time at least on a larger scale.

It is evident that the flash and burning points of kerosene are greatly reduced by small admixtures of more volatile petroleum fractions, such as gasoline, so that grave danger can easily result therefrom.

DISTILLATION TESTS OF FRACTIONS USED

In order that the oils used in this work may be identified the specific gravity was determined by the hydrometer method and distillation cuts of the oils obtained.

No stem temperature correction was necessary in the case of the distillation of the petroleum ether, since the last fraction boiled off at 103 deg. C. as recorded by the thermometer and the emergent stem began at 105 deg. C. in all cases.

The solid curve represents the distillation when stem temperature corrections have been applied. The dotted curves represent the distillation without stem temperature correction.

E. W. Dean in his report on gasoline distillation (Bureau of Mines Technical Paper 214, p. 29) plots the dry point on the 100 cc. ordinate. This is not exactly correct, since the dry point is always obtained before 100 cc., the initial volume of gasoline, has been received. Plotting this results in the curve ending in a sharper bend than it should. To obviate this error, we have plotted the actual dry point on the curve where it is observed and extended a straight horizontal dotted line to the 100 cc. ordinate in order to show where the curve would come had Dean's method of

mate loss in distillation.

The distillations were carried out as prescribed in plotting been used. This actually represents approxiTechnical Paper 166 of the Bureau of Mines, with the addition of reading the number of cubic centimeters

For convenience, the ordinates are labeled both in Centigrade and Fahrenheit readings.

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distilled every 5 deg. rise in temperature as recorded by the thermometer as well as readings at every 10 per cent by volume.

The 250 cc. flask connected with the condenser was filled with 100 cc. of the oil measured in a 100 cc. cylinder. The same cylinder was then used as the receiving vessel. In the kerosene and gasoline distillation the flask was covered with an asbestos box; this being omitted in the distillation of the petroleum ether. Heat was applied so that the distillation proceeded at the rate of about 5 cc. per min., the entire distillation requiring about 25 min. The thermometer used in these distillations was the same as that previously described as being used for the open cup flash and burning point determinations. Besides applying the calibration correction, a correction was added for the emergent stem of the thermometer, varying up to 2.5 deg. C. Formula for corrections was obtained from "Physico Chemical Tables," Castell Evans, vol. 1, p. 126, J. B. Lippincott Co., Philadelphia, Pa. The condenser trough was filled with cracked ice to insure complete condensation. There were from 2 to 3 cc. of residue left in the flask at the end of each distillation. The results obtained by the distillation are shown in the tables and curves following. Fig. 7 contains all of the oils in order that a comparison may be made between them.

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We are indebted to Mr. Frank C. Vilbrandt, instructor of industrial chemistry in this laboratory, for material assistance in the search of the literature for data covering the ground of this report and kindred topics.

BRIEF BIBLIOGRAPHY

I. Adulteration of Kerosene with Gasoline.

Allen, Smithsonian Reports, 1861, 330.

Crew, "Treatise on Petroleum," 1887, 136, 395.
Brandt, "Petroleum and Its Products," 579.
Bacon and Hamor, “American Petroleum Industry,"
Vol. 2, p. 482.

Allen, "Commercial Organic Analysis," Vol. 2, part 2.
Thorpe, "Dictionary of Applied Chemistry," Vol. 4,
p. 138.

Redwood and Eastlake, "Petroleum Technology," p. 227.

Redwood, "Petroleum and Its Products," Vol. 2, 542. II. Effect of Additions of Gasoline on Flash and Burning Points of Kerosene.

Allen and Crossfield, "Fire Hazards."

Flash Points of Oils, Bureau of Mines Tech. Paper
49, p. 11.

Allen, Smithsonian Reports, 1861, pp. 334, 339.
Bacon and Hamor, “American Petroleum Industry,"
Vol. 2, p. 518.

Brandt, "Petroleum and Its Products," p. 417.
Crew, "Treatise on Petroleum," p. 359.

Redwood, "Petroleum and Its Products," Vol. 2, p. 543.
Allen, "Commercial Organic Analysis," Part 2, p. ii.

The Liability for Infections*

THE

BY CHESLA C. SHERLOCK

HE workmen's compensation acts have brought many new problems as to their own liability before employers. Not only that, but they have caused no amount of uncertainty among courts as to just what this liability amounts to.

The compensation acts serve to secure the payment of compensation to workmen who are incapacitated by means of an accidental injury "arising out of and in the course of" the employment. This naturally limits the employer's liability somewhat, but at the same time it raises a point of controversy over what is meant by the term "accident."

The courts have decided, and with good judgment, that the meaning to be given the word accident shall be its ordinary and usual meaning and that it cannot be given a technical meaning if the ultimate purpose of the compensation acts is to be kept in mind and preserved. So, they have said that an accident is any unlooked for and untoward event happening within chance and without design or intention. If a workman suffers such an accident which arises through the employment and out of it, then he is clearly entitled to compensation.

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But it is the fitting of specific cases that come up to the studied expression of the statutes and of judicial opinions that causes the real difficulty. For instance, the question of whether an infection is an accident or not has caused no end of litigation under the acts. It is a well-known fact that workmen engaged in certain occupations are constantly subjected to the hazard of infection. Those who work with paint and stains are in constant menace; those who work in refuse and débris are constantly in danger of experiencing blood poisoning, and those engaged in certain

*Other articles by this author on the same general subject have appeared in CHEM. & MET. ENG. as follows: "The Explosion of Chemicals--Common Law Liability," Vol. 21, No. 2, July 15, 1919, p. 83; "The Explosion of Chemicals-Workmen's Compensation Acts," Vol. 21, No. 3, Aug. 1, 1919, p. 131.

Redwood, "Petroleum and Its Products," Vol. 2, p.
506.

Steingräber, Oesterr. Chem. Zeit., 1900, pp. 589-594;
J. Soc. Chem. Ind., 1901, p. 352.

Weibe and Hebe, "Petroleum," Vol. 7, p. 655 (C. A.,
1912, p. 1842).

III. Explosive and Inflammable Mixtures of Gasoline Vapors.

Redwood, "Petroleum and Its Products," Vol. 2, pp.
500, 503, 504, 508, 510.

Brandt, "Petroleum and Its Products," p. 417.
Allen, Smithsonian Reports, 1861, pp. 335, 340.

Burrell, U. S. Bureau of Mines Technical Paper 127,

p. 9.

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other specific occupations are constantly subjected to the danger of infection through both the blood and the lungs by reason of the materials they work with, the fumes they breathe, or the inherent nature of the work. The long list of cases being reported each year on this subject alone is ample authority for this. statement.

In the earlier days of the compensation practice the courts were called upon almost in the first cases to decide whether or not diseases were accidents. They held in diverse opinions that they were and they were not accidents. These decisions have since given rise to a series of rules which are more or less authoritative and which embody the present law upon the subject.

Unless specifically provided for in the statute, an occupational or industrial disease is not an accident within the meaning of the compensation acts. As to what constitutes an occupational disease there may be some doubt, but the courts have pretty well defined it.

One authority states: "An occupational disease is a disease caused by or especially incident to, a particular employment."

In a New York case, the court said: "An accidental injury. . . is clearly distinguishable from an injury in the nature of a vocational disease, sustained in the course of the employment, where, from the inherent nature of the work, disease is likely to be contracted."

TRAUMATIC DISEASE

It is well known that where certain work is followed certain diseases are very apt to be contracted if the workman persists in following that employment very long. Among the most common of these diseases are various forms of poisoning such as lead and copper poisoning. Since these diseases are of an inherent danger to the work, the courts have almost uniformly held that they are not an "accident" and the workman is not entitled to compensation,

unless the act specifically mentions occupational dis- allowed compensation, it not being necessary for eases, in case he suffers from one.

The rule, however, is different in Massachusetts and other States where the compensation is payable not for accidental injuries, but for "personal injuries." The court of Massachusetts has said that an occupational disease is a personal injury within the meaning of the Massachusetts act. This does not say, however, that all diseases are deemed to be non-compensable in the opinion of the courts. While occupational diseases are excluded because they form a distinct class of their own, there has been a clear reservation on the part of other, ordinary forms of diseases.

him to prove specifically the exact instance when he encountered the poisonous substance which incapacitated him.

The compensation acts are administered in a "spirit of true helpfulness" whenever possible, and they will include infections and diseases within the limitations mentioned above.

The rule is well settled that if the disease is clearly Tat

the result of the employment, or that the employment subjected the workman to a greater hazard to the disease than he would have been subjected to in ordinary employment, or if the disease resulted from an accidental injury, then the workman will be entitled to compensation. This is what is known as the "traumatic disease" theory. If the disease has its origin in trauma, or injury, then it is clearly an accident within the meaning of the acts. For instance, a workman falls off a trestle or a train of cars and because of his injuries and bruises about the chest contracts pneumonia. This is a compensable disease within the meaning of the compensation acts.

Or, another illustration: A workman is required to work for several hours in cold water in order to save a levee or other property of his employer from damage or destruction. Because of the unusual exposure he contracts pneumonia. This is a compensable disease within the meaning of the compensation acts.

INFECTION CASES MORE DIFFICULT

Still another case might be given: A workman is required to clean up débris following a wreck. He scratches his hands and contracts blood poisoning from handling the débris and refuse matter. This is a compensable disease within the meaning of the compensation acts.

Infection, because of its nature, is often a harder matter to determine than a mere disease. An infection, being of such slow and insidious origin that it is extremely difficult to trace it, presents an entirely different problem than an ordinary disease, the symptoms of which generally have their root in some event or happening within the employment. A workman may be able to determine, from his exposure and the like, where he got his disease, but not be able to state just where he got his infection.

It is necessary, however, that the infection be linked up to the employment by some certainty as to time and place and the circumstances under which it was acquired. Generally, employers resist claims for blood poison, for instance, unless the workman reports every little scratch and cut he receives at the time. It is so easy for one to pick up such infections outside the employment that employers are certainly justified in taking these steps for self-protection.

Where the employment is clearly to blame for certain infections, however, the courts will not be too technical in their requirements. In one case a workman employed to mow weeds along a right of way contracts poisoning on his hands and face. He was

Ammonia in Producer Gas*

BY F. K. OVITZ

Assistant Chemist, Bureau of Mines

HE tests described in this paper were made at factory No. 2 of the Hazel-Atlas Glass Co., Washington, Pa., in co-operation with Mr. C. E. Frazier and Mr. C. D. Smith of that company. The object of the tests was to determine the amount of ammonia in gas from producers of the Smith type. At the time the tests were made the importance of ammonia for munitions, refrigeration and agriculture made it desirable that all possible sources of supply should be utilized.

For ammonia-recovery, gas-producers can be divided into two general classes.

1. Producers gasifying the fuel at a low temperature with a comparatively large amount of steam, 3 to 4 lb. of steam per lb. of coal.

2. Producers gasifying the fuel at a high temperature and using a comparatively small amount of steam, about 1 lb. per lb. of fuel.

From the first, or Mond type, 15 to 20 lb. of ammonia, (NH), or 60 to 80 lb. of ammonium sulphate, (NH), SO,, can be recovered per ton of bituminous coal. Information on the quantity of ammonia in gas from the second type, to which the Smith producer belongs, was not available.

DESCRIPTION OF TESTS

The producer plant consists of five producers with inclined grates, each grate having a projected area of 200 sq.ft. The coal is fed into the top of the producer through hoppers which are arranged so that they will distribute it uniformly over the top of the fuel bed. The thickness of the fuel bed during the tests was about 5. feet. The bed was kept in good condition and as free as possible from holes by hand-poking.

The coal used was from the Pittsburgh bed in Washington County, Pa., and contained about 1 per cent of nitrogen on the moisture and ash-free basis. The size was not uniform; at times fairly clean coal of No. 1 nut size was used, while at other times a large amount of fine coal was mixed with it.

Air saturated with steam at 150 to 160 deg. F. was used to gasify the coal, about 4 lb. of air and 1 lb. of steam being used for each pound of coal. The gas was cleaned before being used. From each producer the gas passed through a "hot pipe" into a "downcomer," from which it entered the bottom of a primary scrubber, where it was cooled to about 140 deg. F. by water sprays. From the top of the primary scrubber the gas passed into a large header, where gas from all the producers mixed to some extent. From this header it was sent by exhausters through the tar filters and finally through the secondary scrubbers, where it was washed with water again and cooled to about 100 deg. F. and then delivered into the gas main.

*Published by permission of the Director of the Bureau of Mines.

The water used in the system was cooled in a spray pond and recirculated. The water and tar from the scrubbers and that collected in the header ran into a common drain which emptied into the tar well, where tar was separated from the water. The water was pumped from the tar well to the spray pond, where it was cooled and then returned to the scrubbers.

Gas from a single producer was used for most of the tests. For total ammonia in the gas an open-end sampler was placed in the "hot pipe" about 5 ft. from where the gas left the producer. The sample of gas was passed through the following system to absorb the ammonia and measure the volume:

1. Bottle which served as a trap for condensed water and tar.

2. Four wash-bottles containing dilute sulphuric acid. 3. Filter made from asbestos fiber.

4. Experimental wet meter.

Suction was supplied by a small steam aspirator. The first two tests showed that it was very important to collect all the water which condensed from the gas because a considerable part of the ammonia was dissolved in it. For this reason in subsequent tests bottle No. 1 was arranged so that moisture and tar which condensed in the sampler could drain into it. To determine volatile and fixed ammonia, distilled water was used in the wash bottles in place of dilute sulphuric acid. Gas was drawn through the apparatus at a rate of about 1 cu.ft. per hour.

The liquid from all the bottles was made up to a definite volume. The ammonia in an aliquot part of this volume was determined by adding strong caustic soda solution, distilling and absorbing the ammonia in a measured volume of standard decinormal sulphuric acid. The acid which was not neutralized by ammonia was titrated with standard decinormal caustic soda using cochineal as indicator. The quantity of ammonia per ton of coal was calculated from the results of the titration and the volume of gas produced, by means of the formula given below. While no exact measurement of the quantity of gas produced per ton of coal could be made, 130,000 cu.ft. is assumed for the purpose of making the calculations and is believed to be sufficiently accurate for practical purposes. The weight of ammonia multiplied by 3.8787 gives the weight of ammonium sulphate per ton of coal.

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in the system is given in Table I. All gas volumes are expressed in cubic feet at 60 deg. F. and 30 in. of mercury. Tests Nos. 1 and 2 were made with a large tar filter in front of the wash bottles and the results given on these are low, due to condensation of water vapor from the gas and absorption of ammonia by it. These results should not be used in computing averages. Tests Nos. 7, 9, 10, 11, 12 and 13 were made with distilled water in wash bottles in order that the proportions of fixed and volatile ammonia can be determined.

In addition to the quantity of ammonia in the gas, the percentage of ammonia in the liquor from the tar well and spray pond was determined. The results of these determinations are given in Table II.

An average of 5.70 lb. NH,, or 22.11 lb. ammonium sulphate, was found in the raw gas as the result of seven tests. While the variation between individual tests was quite large, it was no greater than might be expected on account of the changing conditions in the producers during the time tests were being made.

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No detailed study was made of the effect of these changing conditions on the amount of ammonia in the gas, but by watching the variations which occurred in the experimental results and the condition of the producer, it was apparant that the temperature in the top of the producer was a very important factor. The rate of gasification and the amount of steam used, within the limits of daily variation, did not affect results noticeably. Whatever effect these factors had was less than that due to the temperature of the top of the producer.

The temperature in the top of the producer appeared to be influenced by the condition of the fuel bed more than by any other factor. If the fuel bed was not kept free from holes, unconsumed air passed through it and the oxygen burned with gas in the top of the producer, thereby raising the temperature. It required almost constant attention to keep the fuel bed free from holes, and at times it was impossible to do so. Since high temperatures are unfavorable to the formation and production of ammonia, it is very necessary to maintain as low a temperature as possible in the top of the producer

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in order to obtain the best yield of ammonia. The quantity of ammonia found in the gas from one ton of coal was of the same general magnitude as is obtained from the carbonization of one ton of coal in a retort or by-product coke oven. This seems to indicate that the ammonia obtained comes from the destructive distillation of the coal taking place at the top of the fuel bed, and that very little comes from nitrogen liberated during gasification of the fixed carbon. If ammonia is formed from nitrogen liberated during gasification of the fixed carbon, it is apparantly broken up by the passage through the hot fuel bed before reaching the top.

Between 20 and 25 per cent of the total ammonia is in the form of fixed ammonia salts and the remainder is in the form of volatile or free ammonia.

Practically all of the fixed ammonia is absorbed in the water used for scrubbing the gas and accumulates in the pond liquor. Most of it is absorbed before the gas reaches the secondary scrubber, as shown by test No. 12. At the time of the tests the quantity of ammonia in the tar well and pond liquor averaged 0.678 per cent by weight, practically all of it being fixed ammonia. This percentage varies from day to day with the quantity of water in the pond. When fresh water is added to the pond to make up for loss by evaporation, the percentage decreases temporarily, but the total quantity in the pond increases steadily in proportion to the volume of gas scrubbed by the liquor.

Practically all of the volatile ammonia is absorbed in the scrubbing water and later dissipated into the air at various points throughout the system. Tests Nos. 9 and 11 show that the cleaned gas contained only about 0.4 of a pound of ammonia per ton of coal, practically all of which was in the volatile form. The exact distribution of the volatile ammonia was not determined. It depends upon the temperature of the scrubbing water at different points in the system and varies from day to day with the changes in these temperatures and the quantity of water.

It is possible to recover practically all of the ammonia in the gas, either by cooling sufficiently and scrubbing with cold water, or by treating with sulphuric acid. However, because of the low concentration of the ammonia in the gas, less than one-tenth that of by-product oven gas, and the large volume that consequently must be treated per lb. of ammonia recovered, the cost of equipment and recovery would be high. For example, to obtain the ammonia from one ton of coal used in a gas producer, about 130,000 cu.ft. of gas would need to be treated, whereas if the coal were used in a gas retort or by-product oven, about 10,000 cu.ft. would have to be treated and the quantity of ammonia recovered in both cases would be approximately the same. The fixed ammonia, ammounting to about 1.25 lb. per ton of coal, can be recovered by distilling the pond liquor with lime.

House Passes Tungsten Protection Bill On Aug. 21 the House of Representatives passed the Timberlake bill providing for a tariff of $10 a unit on tungstic oxide, which amounts to $10 a ton on crude tungsten. Manufactured tungsten products must pay twice the amount, or $1 per lb. This tariff, in addition to the estimated import price of $8 to $10, will fix American tungsten at $18 to $20 and thus enable domestic producers to compete with imported ore from China and South America, upon which there is no tariff at present.

Recent Chemical and Metallurgical Patents

Complete specifications of any of the United States patents abstracted herein may be obtained by remitting 5c. each to the Commissioner of Patents, Washington, D. C.

Utilization of Tin Scrap.-A method of separating iron and tin based upon the fractional distillation of their chlorides is employed by DANIEL A. and SIDNEY H. WILCOX of Garden City, N. Y., for the utilization of tin scrap. The scrap is compressed and heated in a suitable furnace to such a temperature that a vigorous reaction ensues when chlorine is passed over the metal, both metals being volatilized as chlorides. Or, the scrap may be melted and the chlorine passed through or over the melted metal contained in a bessemer converter, reverberatory, cupola or blastfurnace, electric melting furnace or muffle furnace. In either case, the mixed chlorides are separated by fractional condensation. The tin chloride may be converted into metallic tin or tin oxide by well known methods. The ferric chloride is dissolved in water, reduced to ferrous chloride by passing the solution over hot iron and electrolyzed, using insoluble electrodes, so that the products are pure iron (some occluded hydrogen is present, but this may be removed by heat) and chlorine gas, which may be utilized for the treatment of additional quantities of scrap. (1,310,381; July 15, 1919.)

Method of Producing Lead Salts.-RALPH M. HARRINGTON has developed an electrolytic method for producing white lead and other lead salts. White lead similar to that produced by the "Dutch process" may be produced in the apparatus here illustrated. A cell (1) with anode (2) and cathode (3); the

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cathode is surrounded by a diaphragm (5). The anolyte is a solution of sodium acetate, the catholyte contains in addition sodium hydroxide, carbonate and bicarbonate. The passage of a current though the cell produces lead acetate at the anode and sodium hydroxide at the cathode, thus, 2Na (C,H,O,) + Pb = Pb (C,H ̧O2), + 2Na and Na + H2O NaOH + H. The catholyte is circulated by the pump (15) to a carbonating tower (16), where it meets a current of CO. The NaOH produced at the cathode and this.

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