w 7 t Vj be } Ya ay 4 te y Y Ye topypee i LO P Uy Yjfyy pe PARALLEL tee HL OUT MOLLE Yj Y Y Wy Up (;, y f a a ee BOCUMENTS DiW.sIOT Ua — \Y 76 w 2 oY = FOREST PRODUCTS : LABORATORY A BRIEF ACCOUNT OF ITS WORK AND AIMS HE FOREST PRODUCTS LABORATORY is a unit in the Branch of Research of the Forest Service, United States De- partment of Agriculture. It is located at Madison, Wis., and is conducted in cooperation with the University of Wisconsin. Public § ervice. ‘HE purpose of the Forest Service in the adminis- tration of the Forest Products Laboratory is to conserve American forests by developing the most ee economical methods of converting standing trees into finished products. ‘The purpose is also to make the growing of timber more profitable by increasing the possibilities in the utilization of both used and unused species. The Laboratory seeks to develop not only new and’ more efficient processes, but to find ways of utilizing material which would otherwise be wasted, to find new uses for old materials and new materials for old uses. In a word, the aim is to render practical assistance to the manufacturers and users of wood and wood products and at the same time to promote forest conservation and the practice of forestry. Every American industry and class of consumers which uses or grows wood or any other product of the forest may thus be a beneficiary of the work done atthe Laboratory. Every such industry, class of con- sumers, and timber producers is a potential cooperator in the Laboratory’s work. Its objects are sought not only through experiments conducted at the Laboratory but also through the detail of its men to work on Value of Work. Results Available to Public. Place in Forest Con- servation. Forest Products Laboratory. important problems in the mills and factories and the recetving of representatives of the industries at the Laboratory to work beside its scientific men. a The value of this work has already made itself apparent. ‘he reduction of waste, the better utiliza- | tion of the products of the tree, the utilization of species hitherto wasted, the added life given to many kinds of wood products by more efficient preservative methods, the reduction of the degrade in lumber by efficient dry-kiln methods, and many other savings are -an enormous help in conserving our timber supply. The financial advantage to industries and consumers may be indicated by an example. If the methods of nailing boxes recommended by the Forest. Products Laboratory and adopted by the National Association _ of Box Manufacturers saves but 1 per cent of the annual loss for claims and damages in shipments _ actually paid by the railroads, the saving will be “ig $1,000,000 a year. It has been estimated that the total annual saving as a result of the work of the Laboratory has already reached not less than $30,- 000,000. a _ The value of the Forest Products Laboratory to a a. particular wood-using industry or class of consumers depends to a very large extent upon the use which that = industry makes of it. It is a Government institution supported mainly by Government appropriations, and its advice and suggestions are to be had for the asking. It presents an opportunity for every manufacturer, . user, and timber grower to supplement the information obtained by experience and hard knocks, with technical data obtained through scientific research. The work of the Laboratory is of direct value to those engaged in timber production. Toa very large extent the kinds and sizes of forest trees which should be grown and the purposes for which they should be produced are dependent on the mechanical, physical, and chemical properties of their woods and the uses to Forest Products Laboratory. a scedaaaaadadadaadasanticammacadeadicaueaiiains taiadianededaennee Thelargest of the testing machines, shown here in the process of erection, is capable of exerting a force of a million pounds and can test to destruction wooden columns 30 feet long and a foot square. Allied Problems. Laboratory Established in 1910. istration of the National Forests and of privately play an important part. By reducing the present Forest Products Laboratory. which they can most profitably be put. In the admin- owned timberlands, in the activities of the State For- estry departments, and in the instruction given by the forest schools, the results secured by the Laboratory — waste of three-fourths of every tree cut and making possible the most efficient utilization of the one-fourth — used they are contributing in a very essential way to forest conservation and to profitable timber production. — Through its forest products research the Forest Service — supplements its efforts to bring about the growing of — timber by information which should make possible the” Be. most complete and effective utilization. f In the 11 years the Laboratory has been in operate , it has accumulated a vast store of fundamental infor- mation about the mechanical, physical, and chemical properties of wood. It has also studied the application _ of this information to the problems involved in the manufacture of wood products and chemical products” derived from'wood. In studying manufacturing prob- lems, materials used with the wood often require as much attention as the wood itself. This has necessi- a tated the study of such subjects as glues, moisture- a proof coatings, wood preservatives, laminated wood, and fire-retarding materials. The Forest Products Laboratory was established ‘de 1910 by the United States Forest Service at Madison, Wis., in cooperation with the University of Wisconsin. For several years it was the only institution of its kind in the world conducted with the object of turning the searchlight of research upon wood and its uses and ‘ making the information thus obtained available to the public. eee! In this publication is presented a general outline ‘of the aims and scope of work of the organization. et Organization for Research. RESEARCH is increasingly effective in proportion as it 1s carefully planned and executed. At the beginning of each year a program covering as nearly as practicable the work of the Laboratory for the ensuing year is considered and approved. Individual initiative and responsibility are given the widest pos- sible opportunity, but at the same time the work of - different men is so coordinated by an interchange of ideas among the different sections, and other means, that duplication is avoided and cumulative results are obtained. A carefully worked out system for keeping a check on the status, progress, and correlation of investigative activities and for guiding interrelated projects through the Laboratory has been adopted. Systematically planned programs and carefully coordinated type of organization is in a large measure responsible for the _ practical value of the work already accomplished. The Laboratory is in charge of a director, an assistant director, and a staff comprised of the heads of the _ different research and administrative sections. In each section are men of broad general experience with wood and knowledge of its characteristics, and other special- ists in various wood uses, who devote their whole time Coordi- nated Re- search. Organi- zation of the Laboratory. Forest Products Laboratory. to the study of special problems. These men are recruited, in accordance with the regulations of the — Civil Service Commission, from the professions of engi- neering, chemistry, forestry, and pathology. A sharp distinction is drawn between administrative and investi- __ gative assignments. In this way, research men are re- lieved of other cares and can give their whole thought to the problems in hand. : The work of the Laboratory is distributed among | 2 the following technical sections: Timber mechanics.—Strength of wood and manuface amy tured articles. “aq Timber physics —Experimental and applied kiln- - drying, physical properties, identification, and struc- __ ture of wood. — Wood preservation. —Wood treatments, glues, and laminated construction. mee Pulp and paper—Manufacturing methods and suit- =a ability of-various woods for pulp, paper, and special products. | oe Derived products—Chemical properties and uses of wood and chemical wood products, such as turpentine, _ alcohol, acetic acid, etc. oe. Industrial investigations.—Methods and practices in the lumber and other wood-using industries, grades, a specifications, and mill scale studies. Pathology (an cooperation with the Bureau of Plant Industry).—Decay of timber, molds, stains in manu- factured wood products, and antiseptic properties of — wood preservatives. In addition, there is a section of Laboratory opera- tions which handles the administrative work involved in accounting, engineering, photography, computing, : records, supplies, and the maintenance of the Labora- tory generally. A division in the director’s office reviews and coordinates the results secured, prepares material for publication, and in other ways arranges for its most effective dissemination and utilization. Forest Products Laboratory. The work of each technical section is divided into “projects,” each of which is assigned to one or more of the staff. Before one of these projects is undertaken a preliminary investigation is made and a report pre- pared indicating the nature of the problem, the work done, and results already secured in the same field, and the recommended method of attack. A part of the effort of each section is devoted to the development and maintenance of contact with the lumber-manufacturing and wood-using industries and wood consumers and producers. ‘The resources of the Laboratory are made available to the public through personal contact with the field representatives assigned to study technical problems. Familiarity with the needs of timber growers, wood consumers, and the wood-using industries serves as a guide to direct the investigations made at the Laboratory. 70313°—22——-2 > Projects. Commercial Demonstra- tion. Strength of Various Species. 10 Timber Mechanics. | KNOWLEDGE of the mechanical properties of woods and wood products is essential for their " intelligent and economic use, whether in the factory, — on the farm, in the home, on the railroad, in the mine, — or in the air. Thus development of the airplane and progress in many other lines depend in a large measure ~ on accurate information as to the strength, toughness, elasticity, and other mechanical properties which de- termine the suitability of different woods for various: purposes. To supply this information, over 500,000 — mechanical tests have been made, as nearly as possible — under standardized conditions, so that the tests made for a single purpose will have the broadest application — and will serve for many uses. Data from tests of small clear specimens are now available in published form on 126 species of woods grown in the United States and in unpublished form on 23 native species, as well as data, in some cases — meager, in some cases fairly complete, on about 60. species, principally from South America and the Phil- ippines. ‘These data are of particular value in com-_ paring the properties of the different species, in finding substitutes for the scarcer and higher-priced woods, in selecting species for particular uses, and in estab- Forest Products Laboratory. lishing correct working stresses. ‘The results of these tests’on small, clear specimens also furnish definite information on the variability of wood and show the necessity of grading timber for all uses where strength is of prime importance. A large number of tests have dice been made on full-sized timbers, such as bridge stringers, factory- building timbers, and car sills. These tests have dem- onstrated the influence of defects, such as knots, shakes, and checks on strength; and, altogether with the results of tests on small clear specimens, furnish the basis for the establishment of grading rules and correct working stresses for structural timbers. Ea Wood is subjected to a great variety of preservative Effect of treatments, to many different drying or seasoning processes, to conditioning treatments in preparation for bending, and to many other processes with particular objects in view. Some of these treatments, particu- larly those which use high temperatures or high pres- sures, or both, appreciably lessen the strength of wood and are responsible for large losses. ‘The Laboratory has therefore been studying the effect of such treat- ments on strength, with special reference to kiln- drying and preservative treatments, and, to a smaller extent, methods of conditioning wood for bending. Both commercial sizes and small pieces free from defects are used in these studies. The form and character of the test specimens in each case are as nearly standard as possible, usually varying only in details necessary to make the tests directly applicable to the problem in hand. : Tests have been made on plywood to determine the strength of different combinations of species, the effect of increasing the number of plies, and the effect of varying the ratio of core thickness to total panel thickness. Some data are also available on factors affecting warping, on strength of fastenings for ply- wood, on the efficiency of joints in plywood, and on Treatments on Strength. 12 Forest Products Laboratory. Some of the strength-testing machines, such as the one at the right, are employed chiefly in determining the strength properties of native woods, using small, clear specimens like those on the truck. Other machines are rigged up to test wooden parts. A newly designed airplane wing rib is just being placed in the machine second in line. “v _ we Py ae bi © % 4 i ¥ CF t te Bias! os rs 2 Forest Products Laboratory. the strength in tension. Information on such points as these places the Laboratory in a position to assist users and manufacturers of plywood and veneer prod- ucts in solving problems encountered in developing new uses for these products in the various industries. The results of tests on containers are of particular interest to all shippers, box manufacturers, and trans- ‘portation companies and are also of great importance to the public in general. The damage due to the failure of containers in transportation amounts annu- ally to many million of dollars. ‘There are, in addi- tion, large losses due to improper packing. All of the work done at the Laboratory in this field tends directly to reduce these enormous losses, which are ultimately paid by the consumer. A considerable amount of fundamental data relating to the construction of boxes and crates has been obtained, which finds direct appli- cation in the redesign of faulty containers and in the development of new containers. It is frequently pos- sible to redesign a container so as to reduce the amount of material required, to save shipping and warehouse space, and at the same time to obtain greater service- ability. ‘Ihe investigations apply to all types of both wooden and fiber boxes and~to barrels and crates. One of the interesting facts established by the studies is that a chief source of weakness in wooden containers is inadequate nailing, and that the use of thicker mate- rial will not remedy this defect. | Tests on various species have furnished information on their strength, their resistance to splitting, and their ability to hold nails, which has made it possible to classify the woods in groups for box and crate con- struction. Revolving-drum tests, together with drop and com- pression tests of boxes loaded with either actual or dummy contents, have been used in determining the characteristic weakness of the various types of con- tainers. The Forests Products Laboratory standard 13 Tests on Shipping Containers. Drum Tests. 14 | Forest Products Laboratory. The drum-testing machine, developed by the Laboratoryto stimulate the hazards of transporta- tion, has become standard for shippers, packers, and manufacturers. The boxes shown are packed with electric-light bulbs. Four thousand dollars’ worth of bulbs were furnished by the electric companies concerned for this series of tests to develop a better container. Aside from its value in laboratory tests, the determination of the moisture content of wood is so _______ important in connection with the various uses of wood that every woodworking factory should be- come familiar with the simple process. A knowledge of the moisture content of the stock often makes it possible to avoid costly manufacturing difficulties. Ve 16 Forest Products Laboratory. drum is 14 feet in diameter and can accommodate — packages up to 1,000 pounds in weight. It is fitted — with hazards so arranged that the container under test — follows a regular cycle of drops which simulate those - received in actual transportation. The field for this — work is very large, and much remains to be done in order to develop fundamental relations between the weight and the nature of the commodity, the type of — box to be used, and the thickness of the bottom, side, — and end boards. | Tests of Tests on vehicle and implement parts, airplane parts, Manufac- -. doors, and other articles manufactured of wood are tured Articles. made primarily to demonstrate the fitness of substitute — sa species, to develop or improve designs, and to obtain more economical and efficient use of wood. Consider-— able data in published and unpublished form are now : available on this subject. The limitations and possi- bilities of splices and laminated construction are being — studied with a view to conserving lumber-through the — increased use of small pieces and low grades. ‘This should make possible the use of smaller trees, which | can be grown in comparatively short periods; in short, the character of material on which the country will — have to depend very largely in the future and a ; can oe grown most profitably. — Sh Timber Physics. A KNOWLEDGE of the physical properties of wood is of importance to almost every industry using wood and is essential in kiln drying, impregnation with preservatives, distillation, and other treatments. Omitting the properties already referred to.as mechan- ical—some of which might equally well be classed as physical—_the more distinctly physical properties studied are density, shrinkage, transfusion of mois- ture, hygroscopicity, specific heat, heat conductivity, heat of absorption of water in wood, and permeability _ of wood by liquids and gases. It is often necessary for financial reasons to reduce the time required properly to season wood by open-air drying. Moreover, for many purposes it is desirable to dry the wood more thoroughly than 1s possible in the open air and to employ conditions which will reduce its hygroscopicity, or tendency to shrink and swell. For these reasons dry kilns are almost univer- sally employed for high-grade lumber, and frequently even forthe poorer grades. In the drying of hardwoods it is estimated that about 10 per cent of the material dried is either ruined or lowered in grade. Much of this loss could be avoided by proper methods and kilns, 70313°—22 3 Kiln Dry- ing. _ bt 18 Establishing Scientific Principles. Commercial Kilns. Drying - Schedules. Forest Products Laboratory. and the present results might be greatly improved 1 in other respects. The Forest Products Laboratory bases all its kiln- drying practice on fundamental studies to determine the principles underlying the transfusion of moisture through wood, the effect of changes in atmospheric — conditions upon the rate of transfusion, the effect of various methods of drying and of various drying treat- ments -upon the properties of the wood being dried, and similar studies. In connection with this work a special type of kiln, known as the water-spray kiln and developed at the Laboratory, has found successful ‘ 4 application in many commercial plants where drying requirements are very exacting. Studies of commercial types of dry kilns are well under way. ‘These studies are being made to deter- mine the range of usefulness of the various types and to develop improvements wherever possible. General data on the cost of dry-kiln operation are also being obtained in so far as possible. A comprehensive series of experiments is being con- ducted to determine the proper “drying schedules” for all important commercial woods. ‘These drying sched- ules will show the proper conditions of temperature and humidity to obtain best results in drying, and they will - cover the entire range from an absolutely gréen condi- tion to absolute dryness. A number of drying sched- ules have already been published. ‘This class of work has direct application throughout the wood-using industries. In addition to schedules for lumber of various thicknesses, drying schedules are worked out for special purposes, such as the drying of gunstock blanks, wagon-wheel spokes, and felloes. Special schedules are also developed for very high-grade work, like the drying of aircraft stock and parts, where the utmost strength is essential. Experiments — have also been made to determine the best commercial Forest Products Laboratory. 19 ‘The distinctive feature of the Forest Service water-spray kiln is the control of the humidity in the kiln and, consequently, the drying rate of the lumber, by conditioning the air with sprays of water whose temperature is carefully regulated. The experimental kiln shown is drying oak bolster stock, which appears white because of the end dip used to reduce checking. 20 Steam Bending. Identi- fication. Relation of Structure to Properties. Forest Products Laboratory. “ methods of drying plywood, much of the trouble in the manufacture of which may be traced to faulty or careless drying. , | The proper steam bending of heavy wooden parts, such as artillery wheel rims, presents a number of problems on which the Laboratory has done a limited amount of work and on which it plans to do much more in the near future. The proper moisture condi- tion of the stock, the length and temperature of steam- ing or other preliminary treatment, and the mechanical details of the actual bending must all be worked out - 4 before present high losses in this process can be over- come. 3 | | The accurate identification of woods is important not only in the investigative work of the Laboratory, where it is essential that the kind of wood under test be definitely known, but to wood users generally. There is a steadily increasing demand in the various __ industries for service of this character, and several thousand specimens of wood are annually identified for outside concerns. Microscopic slides and photo- micrographs made from the slides have been prepared : for practically all American woods of importance and are available for study. Authentic specimens of most species are also available. | | Fundamental studies under the microscope to deter- mine the relation of structure to shrinkage have been — under way for some time and are nearing successful completion. Similar studies to determine the relation of structure to mechanical and physical properties are under way, and it is hoped that structure and properties may be definitely correlated. | Forest Products Laboratory. 21 Yi, YY (MillddiidlddaMMdadtiitdde Furniture and vehicle factories are concerned in the research of the Laboratory to reduce losses in the steam bending of stock. To bend a heavy wheel rim, such as is shown, without fracture, requires a careful preliminary conditioning treatment. Wood Preservation. Preservatives. ’ ‘HE amount of wood in the form of railroad ties, 22 mine timbers, posts, poles, and other products which is destroyed each year by decay is approximately equal to the loss from forest fires. It is therefore im- portant to devise methods of treating wood with pre- servatives that will reduce this waste to a minimum. An annual saving of 1% billion of board feet is esti- mated to be possible in the case of railroad ties alone, could. preservative treatment be extended to the 85 million ties at present untreated. In treating operations, the cost of the preservative, such as creosote, zinc chloride, or sodium fluoride, amounts to a high percentage of the total cost. Fur-— thermore, the ultimate success of any treatment is largely dependent upon the preservative used. Much information has already been obtained concerning the preservatives now in common use, but there is need for a great deal of further study with the object of developing new preservatives which will either be cheaper or more effective than present preservatives, or will have properties fitting them for wider use or for special purposes. The value of a preservative is not considered established until it has had a thorough trial under actual service conditions. Forest Products Laboratory. . 93 The life of railroad ties treated with preservatives is often double that of untreated ties. The illustration shows some red oak ties about to undergo an experimental treatment with creosote in the pressure cylinder. Afterwards they will be placed in actual service in one of the test tracks maintained by the railroads in cooperation with the Laboratory. 94 | Forest Products Laboratory. - In the manufacture of water-resistant plywood with casein glue, the glue is applied cold to the a veneer sheets by means of a mechanical glue spreader. The sheets are then placed one on top of another in a press. Forest Products Laboratory. 25 Closely related to the work on wood preservatives Processes of are investigations of preservative processes. These a include the relative efhiciency of commercially estab- lished processes and of new or proposed ones, as well as the fundamental principles involved in the various conditions of temperature and pressure, and other factors entering in the treating process. A third class of wood-preservation studies deals with Suitability of the suitability of various species for treatment, includ- Species. ing the relative resistance to impregnation and decay and the best methods of preparing them for treatment. The protection of wood against fire is another important field in wood preservation. The annual fire loss in the United States is estimated at $250,000,- 000, and is very much higher than the fire losses in European countries. This difference is due largely to Fireproofing. the greater proportion of wooden construction in the United States. Fireproofing the wood or designing the structure so as to offer the least fire hazard are ways of reducing the fire loss and at the same time cutting down the amount of material needed for re- building, thus reducing the drain on our forests. In connection with the manufacture of plywood, Glues for studies have been made of animal glues, such as those Poe made from hide, bone, and other products; and stand-_ ard methods of testing have been developed. A suit- able “standard glue” for aircraft work and high-class joint work in general has been developed and samples made available to manufacturers and users. This is the glue adopted as standard by Army and Navy air- craft bureaus. The development of water-resistant glues of several types, including casein glues and blood-albumin glues, has been progressing for several years, and a number of high-grade glues have been perfected. Tests and experiments are being carried forward to improve these glues still more, especially in their resistance to mots- ture. Methods of testing for the strength and water 26 Forest Products Laboratory. oe ay i ae sil ey ee > we 7 oe rer, a pen og ee sie Wooden patterns for castings can be made practically moisture proof by an aluminum leaf coating and so prevented from warping, swelling, or shrinking. Car wheel patterns protected in this way are now in use by several large foundries. ed : = ng Ferest Products Laboratory. resistance of plywood have been developed and speci- fications drafted for the glues and the plywood, as well as for the raw material from which the glues are made. ‘These specifications have been adopted by the Army and Navy aircraft bureaus. One of the lines of investigation to be taken up recently is the determination of possibilities and best practices in the design and construction of structural members built up of small pieces glued together. These investigations were carried out intensively on aircraft parts, such as wing beams and struts, when the success of the aircraft program was threatened by a sudden shortage of suitable material in the required sizes. Additional intensive work is under way on alr- craft propellers to determine the best species to use _and the best conditions of manufacture and allowable limits for specific gravity, moisture, and direction of grain in individual laminations. The knowledge gained is being applied to extensive investigations of the use of laminated and built-up construction in the various wood-using industries for the manufacture of such articles as shoe lasts, hat blocks, eae pins, wagon bolsters, and wheel hubs. The Laboratory has done considerable work on the moisture resistance of various wood coatings used on airplane propellers, and a very efficient aluminum leaf | coating has been developed which affords protection against moisture over long periods of storage. ‘Tests are now in progress on the durability of these coatings. Other work on wood finishes is contemplated. 27 Laminated and Built-up Parts. Processes of Pulp and Paper Making. Suitability of Species. 28 Pulp and Paper. HE constantly decreasing supply of suitable pulp- woods and the ever-increasing demand for paper of all kinds, especially newsprint paper, have com- bined to produce so serious a situation that investiga- tions into methods of conserving the supply of pulp- wood and increasing the production of paper are of paramount importance. 7 The Laboratory is conducting experiments on methods of making wood pulp and has already de- veloped several important improvements in the stand- ard chemical processes. A ground-wood branch lab- oratory was operated at Wausau, Wis., for several years, at which the best conditions for grinding pulp were determined. ‘The work of this laboratory was completed in December, 1913, and the results published in a series of bulletins. A very important field of research lies in determining the suitability of various little-used woods as substitutes for those most commonly used. Practically all avail- able species which give promise of suitability are being. investigated, and proper methods of grinding or cooking of most of the important ones have already been worked out. ——e oe od ee a? ee Forest Products Laboratory. 29 Special ‘small-scale digesters for the manufacture of chemical pulp provide facilities for the study of pulping problems at a moderate cost, preliminary to a cooperative mill test. 30 Utilization of Waste. Pulp Decay. Special Uses. Forest Products Laboratory. Studies of waste utilization in the pulp and paper industry have been in progress for some time along a number of distinct lines. For example, feasible methods of turning sawmill waste, such as slabs, into pulp have been determined. ‘The use of a certain’ percentage of spent tan bark in the manufacture of roofing felts has been investigated and a method de- veloped whereby what was formerly a waste of the tanning industry 1s now in profitable commercial use. The possibility of using hemlock bark waste er tannin has also been demonstrated. A commercially feasible method of pereeeae both the parafhn and the fiber from waxed paper trimmings - has been developed. Studies of the wastes incident to _ the pulp industries, such as sulphite waste liquors and © soda liquors, in which are now carried off approxi- mately half of the wood that enters into the digesters, are to be undertaken intensively as soon as funds and equipment ‘become available. The suitability for paper making of hull fiber and second-cut cotton linters, formerly of little value, has been demonstrated and a method of preparation worked out that has proved commercially successful. A recently begun investigation of the deterioration of pulpwood and wood pulp through fungous infec- tion, now estimated at $5,000,000 a year, is leading ~ to the proper remedies for this great economic loss. The possible use of wood pulp as a substitute for other material in various products has been demon- strated in a number of instances where the Laboratory has suitable equipment or where arrangements could be made with manufacturers. Molded articles, such as buttons and electrical fittings; compounds of cellu- lose, such as smokeless powder, lacquers, and artificial silk; and waterproof containers are examples of wood- pulp products the commercial use of which is possible whenever the relative costs of the pulp and of the raw ‘materials in use make them practicable. Forest Products Laboratory. 31 Old newspapers can be de-inked by the use of bentonite, a highly colloidal clay, to which the ink particles adhere after being loosened from the paper in the pulp beater. The pulp is then ready to be used again in the manufacture of newspaper. samplers. am J ey ee : : : > ; 2 TEKS . vis wen pe s . J ae : Py Fae value of the various species for different e desion, construction, and operation of commer- Operation C 4a ’ ’ p of Commer- ants for wood preservation, distillation, kiln- © | cial Plants. , and similar work may be undertaken in ex- al cases when a new process will be demon-— and the plant used, at least in part, for experi- ts, referring applicants, however, to consulting 1eers for assistance as to details. a ae may, on request, examine the a "waste et. to obtain information of general to the industries concerned. short cooperative courses of instruction are Courses of Instruction. Priority of applica- ae admission to the courses, and the classes Bele information concerning any of the se of Laboratory — will be gladly furnished. Inquiries d 1 be addressed to the Director, Forest Products rz atory, Madison, Wis. WASHINGTON : GOVERNMENT PRINTING OFFICE : 1922 ~