culties in transportation of fish in a number of localities, notably on the North Carolina and Virginia coasts, where the service to the northern markets was upset by the congestion of the railroads.

MILL AND ELEVATOR DUST EXPLOSIONS AND FIRES.

A general fire and explosion prevention campaign has been carried on in order to reduce the great losses due in many instances to lack of knowledge on the part of employees. At meetings held in various parts of the country mill and elevator owners and employees were shown, by means of moving pictures, lantern slides, and miniature dust explosions, the danger of dust explosions and fires, and were made acquainted with the circumstances under which they occur. Following the meetings the various mills and elevators were inspected and recommendations made to the managers and superintendents with reference to arrangements which appeared dangerous. The men were then asked, by means of special cards, to pledge themselves to take all possible precautions to prevent fires and explosions in the plants where they were employed. The signing of the cards was acknowledged by the department and appropriate cards sent to the men. Through posters, circulars, and the like, much publicity was given to the work, and, while from the nature of the situation it is as yet impossible to prove in figures that this educational campaign has resulted in the conservation of much grain and feed that might otherwise have been lost by fire, the impression prevails in the industry that such has been its effect.

An educational campaign was conducted among the thrashermen and farmers, particularly in the Northwest, on the methods of equipping thrashing machines with devices to prevent explosions and fires. These measures include systems for grounding the machine to carry off static electricity, the installation of especially devised suction fans placed on the machine, which not merely reduce the explosion fire hazard but also collect smut spores and improve the grade of grain by cleaning and removing dust and foreign materials, and the use of automatic fire extinguishers. As a result of the campaign the equipment of thrashing machines in the Northwest with explosion and fire prevention devices has become very general, and most of the manufacturers of thrashing machines are planning to make some of these devices standard parts of their equipment.

COOPERATION WITH WAR AGENCIES.

The Bureau of Chemistry has cooperated in many ways with the United States Food Administration. It has acted in a consulting capacity, furnishing technical information concerning trade practices, methods of manufacture, and the like, and it has in many instances, especially in the early days of the war, through its inspectors, made a number of special investigations. It has been instrumental in securing the cooperation of State and municipal food and feed control officials. It has assisted particularly the Food Administration's baking division, and it organized the supervision of commercial bakeries throughout the country, working through State and municipal officials. It has caused thousands of inspections of bakeries to be made, with the result that greater compliance with the baking regulations was secured than would otherwise have been possible.

This work has been very thorough in certain States where close cooperation between the Food Administrator and the local food-control officials existed. It has been less effective in those States where such cooperative relations could be less perfectly established.

The bureau has cooperated also with the Food Administration in the control of certain perishable products, in the control of the fat and oil supply, and in the control of canned goods, especially with a view to the conservation of tin plate.

It has also cooperated in the control and licensing of the arsenic and insecticide industries. As a result, an adequate quantity of such insecticides was made available.

In this connection it may be mentioned that the control by the War Department of the acetic acid supply threatened to make it impossible for a Paris green to be manufactured. The bureau assisted in introducing the use of distilled vinegar for this purpose instead of acetic acid. It has cooperated also in controlling and licensing the ammonia producing and the fertilizer industries, a matter of much importance, since an equitable distribution of ammonia is necessary if both the refrigeration and explosives requirements of the country are to be met.

When war was declared the services of the Bureau of Chemistry were offered to the Quartermaster General, since it seemed that the organization of the bureau, with its laboratories scattered through the principal producing centers of the country, was eminently adapted to assist in the purchase and inspection of the vast quantity of foodstuffs and drugs needed by the Army. At first but little use was made of the bureau's facilities. Gradually the officers in charge of some of the quartermaster's depots outside of Washington requested representatives of the bureau to undertake the examination of supplies offered. Later similar requests were made in Washington. The volume of such requests has steadily increased until a vast amount of work of this nature is being done by the bureau. In these matters no responsibility has been placed upon the bureau, either with reference to the preparation of specifications, the letting of contracts, or the acceptance of deliveries. The bureau's function in these instances. is largely limited to the objective report of the chemical or physical examination of the goods.

The demand upon the bureau's force, already greatly depleted, became so great that, in spite of the fact that a very large proportion of the time of the bureau's field force was given to this work, it became necessary for the Quartermaster's Department to assign a limited number of additional men to the various laboratories of the bureau. These chemists work under the immediate supervision of the chemists in charge of the laboratories. The work, having developed gradually as a matter of evolution rather than according to a predetermined plan, resulted in a not inconsiderable amount of unnecessary work and duplication. In consequence it has become necessary to establish in the bureau a special office to deal with the relations between the bureau and the Quartermaster's Department, in so far as food and feedstuffs are concerned. At the same time, for the more expeditious conduct of this work, it will be necessary to establish special laboratories in localities in which the bureau now has no laboratories.

As a supplement to the chemical and physical examinations which have heretofore been requested, the bureau was asked to undertake examinations by way of factory inspection. A large amount of work has been done for the Quartermaster's Department upon the waterproofing, mildewproofing, and fireproofing of various materials, and a large quantity of such materials has been tested. Many examinations of bag, strap, harness, belting, upper, and sole leathers have been made, and investigations have been conducted on the suitability of leathers for certain special purposes. Also, a great number of samples have been tested. In addition, much work has been done for this department on the baling of goods and on shipping containers for overseas.

Very excellent cooperative arrangements have been established with the Sanitary Corps of the Army. A predetermined plan, which in practice has proved satisfactory, was developed almost with the organization of the food section of that corps. The field laboratories of the bureau were placed at the disposal of that section for use in making nutritional surveys at the cantonments, for the elimination of waste, and for the improvement of the dietary. In this connection. the bureau's field force examined a large variety of materials, varying from garbage to the foodstuffs that are privately purchased by the enlisted men in the zones about the cantonments. The Sanitary Corps placed in those laboratories, in which the volume of work required was excessive, officers well trained in methods of chemical analysis, some of whom were formerly members of the Bureau of Chemistry. The bureau has cooperated also with the Sanitary Corps in the matter of the dehydration of fruits and vegetables, and this corps has placed in the laboratories of the bureau men to assist in the securing of properly prepared and satisfactory dehydrated products. For the Surgeon General of the Army the bureau has undertaken to manufacture and supply the rare sugars which are required in some quantity and variety for the use of the bacteriologists of the Medical Corps.

Much of the chemical research and development work required by the Bureau of Aircraft Production has been placed under the supervision of the Bureau of Chemistry. This work has become so extensive that a number of men have been detailed to it by the Bureau of Aircraft Production. In this manner the Bureau of Chemistry has assisted in securing photographic chemicals and, as indicated elsewhere (p. 15), it has undertaken the production of sensitizing dyes which are so necessary in photographing under certain adverse conditions of illumination. Through its field laboratories it has examined many shipments of castor beans and castor oil offered for entry with a view to determining whether they are suitable for use in the preparation of lubricants. It has assisted in the study of airplane "dopes." It has investigated and reported upon the operation of a number of plants producing materials required in airplane manufacture, especially certain alcohols and

ketones.

Laboratory space and manufacturing equipment have been turned over to the various branches of the War Department for their use. Several members of the bureau have served on important committees of the War Industries Board, and in a number of instances

the bureau, through its inspectors, has furnished information to that board.

The bureau has furnished the War Trade Board with experts who have devoted the greater part of their time to assisting that board in considering requests for export and import licenses for chemicals. The bureau has assisted the War Department in a number of ways of value in connection with gas warfare.

TECHNOLOGICAL INVESTIGATIONS.

DUST EXPLOSIONS.

In cooperation with The Pennsylvania State College, Department Bulletin 681, "Grain-Dust Explosions: Investigation in the Experimental Attrition Mill at The Pennsylvania State College," was issued. The inflammability of a number of dusts has been determined and an experimental apparatus developed to study the ignition by different means of dusts in suspensions of varying densities. The effect of moisture content upon the inflammability of oat-hull byproducts has been investigated. Arrangements have been made with two industrial companies to test the practical value of passing inert gases containing too little oxygen to support combustion into grinding machinery as a preventive of explosions.

Various methods of designing milling equipment, to prevent the accumulation of static electric charges, have been proposed. Many special investigations of explosions and fires in grain mills, elevators. food plants, and storage warehouses were conducted to establish the specific cause and to develop methods of prevention. The numerous fires in the cotton gins of the Southwest last year led to a preliminary investigation which indicates that possibly static electricity may be a causative factor in these disasters. The matter will be pursued further during the coming season.

COLOR INVESTIGATIONS.

The guiding principle in this work is that the mechanisms of organic reactions and the laws that govern them should be studied, as well as the practical details of manufacturing processes. For these studies the works chemist has neither leisure nor opportunity. Yet such fundamental knowledge is vital to the progress of the industry. For example, the industry is seriously hampered by the lack of suitable quantitative methods for the determination of many of the substances with which it deals. It is, therefore, difficult for the works chemist to exercise such exact control over many of the processes as will yield the maximum amount of the desired product. Consequently much attention is being given to the development of quantitative methods for the determination of the more important substances. Furthermore, chlorination, sulphonation, and oxidation, especially in the vapor phase, and the behavior of catalysts have been made the subject of experimental and theoretical studies which already have yielded what promise to be new methods for the production of phthalic anhydrid, H-acid, and benzaldehyde and benzoic acid. Of these, the process for making phthalic anhydrid is being developed commercially in a satisfactory manner.

Methods have been devised for chlorinating, sulphonating, and nitrating cymene, and numerous useful compounds and dyes have been prepared from it. Cymene is a hydrocarbon obtained as a byproduct from the sulphite-spruce paper industry. Two million gallons per annum are estimated to be available. No commercial use is now made of it. A paper on the nitration of paracymene has been published.

New methods for refining anthracene pressed cake have been devised, and processes for obtaining pure anthracene, phenanthrene, and carbazol are in an advanced stage of development. Improvements have been made in the methods for purifying anthraquinone. Inasmuch as these projects required that vapor pressure measurements upon a large number of compounds be made, a new dynamic method for measuring vapor pressures was developed.

A large number of dyes necessary for the sensitizing of gelatin emulsions of silver halids required in photography are being prepared and studied in cooperation with the Bureau of Aircraft Production and the Bureau of Standards. The production of a large number of quinolines used in the synthesis of these sensitizing dyes is in progress.

A number of dyes useful in biological research are being prepared and studied. Among them are included known and new sulphophthaleins for the measurement of the hydrogen-ion concentration of solutions and vital red required in considerable quantities by the Surgeon General for certain blood studies.

A compilation of the literature of all American patents on dyes is in an advanced stage of preparation.

Five patents based on work of the Color Laboratory have been allowed and a number of others are pending.

NAVAL STORES.

Data on the extent of adulteration of turpentine and misgrading of rosin for the last three years have been compiled. Information on the commercial weighing of naval stores has been gathered. Observations which indicate that adhesives containing rosin in combination with various oils can be used satisfactorily in the manufacture of fiber and wall board requiring special waterproof properties have been made. Glass rosin type samples have been deposited with the Chamber of Commerce, Pensacola, Fla., and with the United States Food and Drug Inspection Station, Boston, Mass. The British Government Inspection Bureau has been assisted in purchasing rosin. The description of a simple colorimeter for determining the color grade of turpentine has been published. A satisfactory process of refining wood turpentine applicable to the commercial plant has been developed.

LEATHER, TANNING, AND FINISHING MATERIALS.

Data on the wear resistance of leather from different parts of the hide have been published, and a report on a mechanical wearing test of shoe-soling materials is in press. The description of a volumenometer specially designed in this connection has been printed. A bulletin on domestic sumac, giving detailed directions for the proper gathering and curing of sumac, has been published.