V -^ < CV Y * f) ^i-. - % / ■ X & : ^ -% ^ ,0° ■ V s - ^. v * D S . V I 8 £°,. « i * .«5 ^ ^ .** \ ,i"; .o- 5 ^ - K 0' . \ I 1 * a< -X V X 0c ^. '^ - >^ 1 » i ■*>, ^x aV ^c ^ ^ ^Wa Digitized by the Internet Archive in 2011 with funding from The Library of Congress http://www.archive.org/details/agriculturalengiOOdavi Agricultural Engineering Farm Science Series Agricultural Engineering By J. B. Davidson, Iowa State College of Agriculture and Mechanics Arts Field Crops By A. D. Wilson, University of Minnesota and C. W. Warburton, U. S. Department of Agriculture Beginnings in Animal Husbandry By C. S. Plumb, Ohio State University Soils and Soil Fertility By A. R. Whitson, University of Wisconsin and H. L. Walster, University of Wisconsin Popular Fruit Growing By S. B. Green, University of Minnesota Vegetable Gardening By S. B. Green, University of Minnesota {OTHER BOOKS IN PREPARATION) Agricultural Engineering A TEXT BOOK FOR STUDENTS OF SECONDARY SCHOOLS OF AGRICULTURE COLLEGES OFFERING A GENERAL COURSE IN THE SUBJECT AND THE GENERAL READER BY J«4 ROWNLEE DAVIDSON, B. S., M. E. Member American Society of Agricultural Engineers Member American Society of Mechanical Engineers Member Iowa Engineering Society Professor of Agricultural Engineering, Iowa State College Joint Author "Farm Machinery and Farm Motors" ILLUSTRATED ■>' COPYRIGHT, 1913 By WEBB PUBLISHING COMPANY St. Paul, Minn. All Rights Reserved ©CI.A347046 PREFACE Believing that the study of Agricultural Engineering should fill an important place in the training of the young man who would make farming the object of his life's work, the author has attempted to furnish in this volume an aid in supplying this part of his training. The application of agricultural engineering methods to agriculture should not only raise the efficiency of the farm worker but should also provide for him a more comfortable and healthful home. This volume has been written primarily as a text for secondary schools of agriculture, and for colleges where only a general course can be offered. Claim is not. made for much new material concerning the subjects discussed; but rather an attempt has been made to place under one cover a general discussion of agricultural engineering subjects which hitherto could not be secured except in several vol- umes and hence impractical for text-book purposes. No attempt has been made to outline the exact method for the teaching of the subjects, as this must vary with con- ditions. It is desirable that classwork upon the text should be supplemented by laboratory work. The nature of the laboratory work will depend upon the equipment available. It is suggested that the equipments on the nearby farms may be used to good advantage. Sample machines to be used for study may be secured by co-operation with dealers in farm machinery. The author will be very glad to receive criticisms and suggestions from those using this text, in regard to how it may be improved and made more useful. The correction of any errors will likewise be appreciated. 8 PREFACE Although written primarily for use as a text book, it is hoped that this volume will be of interest to those engaged in practical agriculture. Many of the illustrations were made from photographs secured from the files of the Iowa State College. In addi- tion, the trade literature of the following manufacturers was drawn upon : International Harvester Company of America; John Deere Plow Co. of Moline, 111.; Moline Plow Co.; W. & L. E. Gurley; Eugene Dietzen Co.; Keuffel and Esser Co.; Parlin and Orendorff Co. ; Fairbanks, Morse and Co. ; Hayes Pump and Planter Co. ; Hunt, Helm, Ferris & Co. ; J. D. Tower and Sons Co. ; Western Wheeled Scraper Co. ; Pattee Plow Co.; Avery Company; Emerson-Brantingham Co.; M. Rumely Co. ; American Seeding Machine Co. ; Oliver Chilled Plow Works; Hart-Parr Co.; Red Jacket Mfg. Co.; A. Y. McDonald Mfg. Co. ; Louden Machinery Co. ; Gale Mfg. Co. ; Sandwich Mfg. Co.; Aspenwall Mfg. Co.; Wilder-Strong Implement Co. ; Port Huron Engine and Thresher Co. ; J. L. Owens Co.; Charles A. Stickney Co.; Twin City Separator Co.; Cushman Motor Works; F. E. Meyers & Bro.; D. M. Sechler Carriage and Implement Co.; Roderick Lean Mfg. Co.; Janesville Machine Co.; LaCrosse Plow Co.; The John Lanson Mfg. Co.; J. I. Case Plow Works; J. I. Case Thresh- ing Machine Co. ; Johnson & Field Mfg. Co. ; Racine Sattley Co. ; Kewanee Water Supply Co. ; and others. Valuable assistance was secured from Mr. M. F. P. Costelloe, Associate Professor of Agricultural Engineering, Iowa State College, who read the manuscript for Parts I to IV, inclusive. Mr. J. H. Weir, the Editor, did very efficient work on the manuscript, which is appreciated. Ames, Iowa. J. B. Davidson. February, 1913. CONTENTS Chapter I. II. III. IV. V. VI. VII. VIII. IX. X. XI. XII. XIII. XIV. XV. XVI. XVII. Introduction PART I— AGRICULTURAL SURVEYING Definitions and Uses of Surveying Measuring — -The Use, Care, and Adjustment of the Instruments Field Methods Map Making Computing Areas The United States Public Land Survey Instruments for Leveling; Definitions . Leveling Practice PART II— DRAINAGE Principles of Farm Drainage The Preliminary Survey . Laying Out the Drainage System Leveling and Grading Tile Drains Capacity of Tile Drains Land Drainage Construction of Tile Drains Open Ditches ..... Drainage Districts Page 13 16 18 24 28 34 38 42 49 56 64 67 73 78 86 96 103 108 XVIII. XIX. XX. XXI. XXII. PART III— IRRIGATION History, Extent, and Purpose of Irrigation . Irrigation Culture Supplying Water for Irrigation .... Applying Water for Irrigation Irrigation in Humid Regions and Sewage Dis- posal Ill 115 122 129 136 10 CONTENTS Chapter XXIII. XXIV. XXV. XXVI. XXVII. XXVIII. XXIX. XXX. XXXI. XXXII. XXXIII. XXXIV. XXXV. XXXVI. XXXVII. XXXVIII. XXXIX. XL. XLI. XLII. XLIII. XLIV. XLV. XLVI. XLVII. XLVIII. XLIX. L. LI. LII. LIII. LIV. PART IV— ROADS Page Importance of Roads ...... 141 Earth Roads 147 Sand-Clay and Gravel Roads .... 153 Stone Roads 160 Road Machinery 167 Culverts and Bridges 175 PART V— FARM MACHINERY The Relation of Farm Machinery to Agricul- ture .... 180 Definitions and Principles .... 186 Materials 195 The Plow 199 Harrows, Pulverizers, and Rollers . . 211 Seeders and Drills 223 Corn Planters 231 Cultivators 237 The Grain Binder or Harvester . . . 244 Corn Harvesting Machines 251 Hay-Making Machinery 258 Machinery for Cutting Ensilage .... 273 Threshing Machines 278 Fanning Mills and Grain Graders . . . 282 Portable Farm Elevators 287 Manure Spreaders 292 Feed Mills and Corn Shellers . . . 298 Spraying Machinery 303 The Care and Repair of Farm Machinery . 309 PART VI— FARM MOTORS Elementary Principles and Definitions . . 313 Measurement of Power . . . . . 316 Transmission of Power ' . 320 The Horse as a Motor 327 Eveners 334 Windmills 339 The Principles, of the Gasoline Engine . . 344 CONTENTS 11 Chapter Page LV. Engine Operation ....... 350 LVI. Gasoline and Oil Engine Operation . . . 354 LVII. Selecting a Gasoline or Oil Engine . . 361 LVIII. The Gas Tractor 370 LIX. The Steam Boiler 376 LX. The Steam Engine . . • 385 LXI. The Steam Tractor 389 PART VII— FARM STRUCTURES LXII. Introduction and Location of Farm Buildings . 395 LXIII. Mechanics of Materials 402 LXIV. Mechanics of Materials and Materials of Construction 406 LXV. Hog Houses 414 LXVI. Poultry Houses 425 LXVII. Dairy Barns . . . . . . . .436 LXVIII. Horse Barns 442 LXIX. Barn Framing 445 LXX. The Farmhouse 451 LXXI. Constructing the Farmhouse .... 455 LXXII. The Silo 461 LXXIII. The Implement House and Shop . . . 473 PART VIII— FARM SANITATION LXXIV. The Farm Water Supply 480 LXXV. The Pumping Plant 486 LXXVI. Distributing and Storing Water . . . .491 LXXVII. Plumbing for the Country House . «. . 497 LXXVIII. The Septic Tank for Disposal of Farm Sewage . 501 LXXIX. The Natural Lighting of Farm Buildings . 506 LXXX. Lighting the Country Home 510 LXXXI. The Acetylene Lighting Plant .... 515 LXXXII. The Electric Lighting Plant 520 LXXXIII. Heating the Country Home .... 525 LXXXIV. Ventilation of Farm Buildings .... 531 PART IX— ROPE WORK LXXXV. Ropes, Knots, and Splices 537 Agricultural Engineering INTRODUCTION Engineering. Denned briefly, engineering is the art of directing the forces of nature to do economically the work of man. The pursuit of agriculture requires many mechani- cal operations whose execution involves the use of engineer- ing methods. Consider the production of wheat. The plowing, the pulverizing and smoothing of the soil, the cleaning and grad- ing of the seed, the drilling of the seed, the harvesting, the thrashing, and the hauling of the crop to market, are all mechanical operations to which the skill of the mechanic or engineer should be applied in order to obtain the best results. In like manner if the production of other crops be con- sidered, it will be found that there are many operations to be performed in connection therewith, which will require the directing of the forces of nature or the application of engineer- ing principles. Agricultural Engineering. In the broadest sense, agri- cultural engineering is intended to include all phases and branches of engineering directly connected with the great industry of agriculture. In America it is only recently that the term agricultural engineering has come into general use. The term rural engineering is used by some to designate the same subject. It is only within the last few years that the importance of agricultural engineering as a branch of agricultural education has been recognized. A knowledge of soils and of the plants 14 AGRICULTURAL ENGINEERING and animals of the farm is essential to those who would make good farming the aim of their life's work, and these subjects should be carefully studied by the agricultural student. But the study of agricultural engineering is quite as impor- tant in assuring that efficiency in farm management which results in the greatest and most permanent benefits. The truth of the foregoing statement is better understood when one learns that the producing capacity or earning ability of the farm worker is in direct proportion to the amount of power he is able to control. There was a time when man tilled the soil by his own individual efforts, depending upon no other source of power than the strength of his own body. Later, one beast per worker was pressed into service to draw suitable implements. Still later, two animals were used, and development has continued, until at the present time we have reached the "age of four-horse farming." In other words, the four-horse team is now recognized as the most efficient one for field work. Man as a motor or producer of power is able to develop about one-eighth of one horsepower. When use was made of one good horse per worker, man's labor capacity was increased eightfold. When four horses became the unit, his efficiency was multiplied about 32 times. Just now there is a desire to increase still further the amount of power for each farm worker, by the use of powerful tractors or engines arranged for drawing and operating farm implements. The application of power to farm operations, which must come mainly through the use of machinery, is only one branch of agricultural engineering. Some element of agricultural engineering is concerned in nearly every department of agricultural endeavor. It serves man in one or both of two ways : (1) By making it possible to increase the capacity of the worker, as just explained; and (2) by making condi- INTRODUCTION 15 tions more desirable and satisfactory, either by relieving the worker of hard labor, or by providing more healthful and pleasing surroundings. Farm Mechanics. The term Farm Mechanics is not as comprehensive in meaning as Agricultural Engineering, yet it is often used to designate the same branch of education. Mechanics is the science of forces and their actions; whereas engineering proper is based upon a knowledge of these forces and treats more particularly of the directing of them to secure their most advantageous use. In this text the subject of agricultural engineering is presented under the following heads : Agricultural Surveying. Drainage. Irrigation. Roads. Farm Machinery. Farm Motors. Farm Structures. Farm Sanitation. The importance and relation of these various branches to agriculture are discussed in the separate parts of the text devoted to each. QUESTIONS 1. Define the term engineering. 2. Show how engineering methods are involved in crop production. 3. Define the term agricultural engineering. 4. Is there any relation between the producing capacity of a farm worker and the amount and kind of power used? 5. Distinguish between "farm mechanics" and "agricultural engineering." 6. Name the principal branches of agricultural engineering. PART ONE— SURVEYING CHAPTER I AGRICULTURAL SURVEYING Surveying. The object of agricultural, or land, survey- ing, in its generally accepted meaning, is to determine and place on record the position, area, and shape of a tract of land. The various steps taken to accomplish this end con- stitute a survey. In addition to the field work with instru- ments for measuring distances, angles, and directions, a field record, containing figures, notes, and sketches concern- ing the work must be kept; the areas must be computed; and usually a map, plat, or profile made showing the tract of land surveyed. The art of land surveying includes all of these various lines of work. Uses of Surveying. Agricultural students can well afford to spend some time in the study of land or agricultural surveying. The object of the work here presented on sur- veying is to enable the student to measure and calculate accurately the areas of the various fields of the farm and to locate the buildings; to prepare a good map setting forth the relative size and position of the fields, buildings; and fences, and indicating the drains; and to prepare the student for the study of drainage and irrigation. It is necessary for the farmer to know the areas of his fields in order that he may determine accurately the yields of the various crops grown. A survey will enable the farmer to so divide his farm into fields as to facilitate a system of crop rotation. SURVEYING 17 A good map is a means of recording the location of drains and water pipes laid beneath the surface of the ground. It will also enable the farmer to direct the work of the farm more easily, and to make a study of the most convenient arrangement of fields and buildings. This method is used by architects and engineers in planning buildings and engineering work such as factories and railroads. Divisions of Agricultural Surveying. The work of mak- ing a survey resolves itself into three stages or operations, as follows : 1. Measuring and recording distances and angles, involv- ing the use, care, and adjustment of the instruments used in the survey. 2. Drawing the tract surveyed to a suitable scale, or proportion. 3. Calculating the areas of the tracts surveyed. QUESTIONS 1. What is the object of agricultural surveying? 2. Define a survey. 3. To what use can a knowledge of surveying be put by those con- nected with agriculture? 4. In what way will a map be of use to the land-owner? 5. Describe the three divisions of agricultural surveying. CHAPTER II MEASURING; USE AND CARE OF INSTRUMENTS Instruments for Measuring Distances. Often students are led to think that it is impossible to make a survey without a very elaborate equipment of expensive instruments, but this is not true. An agricultural survey, such as is usually required by the farm owner or manager, can be accomplished with simple and quite inexpensive instruments. Where the boundary of the tract of land is known, a practical survey may be made with a surveyor's chain or tape. Gunter's, Chain. Much of the land in the United States was surveyed originally with the Gunter's chain, which is now but little used. This chain is 66 feet long, divided into 100 links, each of which, including the connecting rings at the ends, is 7.92 inches long. The links are made of steel or iron wire, and the better chains have the open joints soldered or brazed to- gether. The reason for making the Gunter's chain of the length of 66 feet or 100 links is owing to its convenient relation to the stand- ard units of length and area in use. The chain is 1-80 of a mile, or two rods. A square chain is 1-10 of an acre. Thus ten square chains make an acre, and this, together with the fact that links may be written as a decimal of a chain, greatly facilitates computations. To illustrate, 1625 square chains equal 162.5 acres, and 15 chains and 24 links equal 15.24 chains. Fig. 1. The Gunter's chain, folded. SURVEYING 19 The Gimter's chain has been used on all United States land surveys; and in deeds of conveyance and other legal documents, when the word chain is used, the Gunter's chain of 66 feet is meant. Table of Linear Measure. 12 inches (in. or ") make 1 foot (ft. or ') 3 feet " . 1 yard (yd.) 5 l A yards or 16^ feet " 1 rod (rd.) 320 rods " 1 mile (mi.) Equivalent Table Mi. Rd. Yd. Ft. In. 1 320 1760 5280 63360 1 5V 2 1VA 198 1 3 36 1 12 Table of Gunter's Chain Measure. 7.92 inches (in. or ") make 1 link (li.) 100 links " 1 chain (ch.) 80 chains " 1 mile (mi.) Equivalent Table Mi. Ch. Li. In. 1 80 8000 63360 1 100 792 1 7.92 Table of Surface Measure. 141 square inches (sq. in.) make 1 square foot (sq. ft.) 9 " feet "1 " yard (sq. yd.) 30M " yards " 1 " rod (sq. rd.) 160 " rods " 1 acre Equivalent Table A. Sq. rd. Sq. yd. Sq. ft. Sq. in. 1 160 4840 43560 6272640 1 30^ 272 14 39204 1 9 1 1296 144 20 AGRICULTURAL ENGINEERING Surveyor's Measure. 625 square links (sq. li.) make 1 square rod (sq. rd.) 16 " rods " 1 " chain (sq. ch.) 10 " chains " 1 acre 640 acres " 1 square mile, or one section Equivalent Table Sq. oh. Sq. rd. Sq. li. 10 160 100,000 1 16 10,000 1 625 Cloth and Metallic Tapes. Tapes made of linen cloth are not practical to use in land surveying, even when well made and water-proofed. They will stretch when pulled up tight, and are difficult to handle in the wind. A cloth tape is much improved when small brass wires are woven lengthwise into it to check the tendency to stretch. Such a tape is said to be a metallic tape. These tapes are made to wind into a case of sheet metal or leather, and for this reason are very convenient to carry about. Steel Tapes. The steel tape is now the standard measuring in- strument, as it has many advan- tages. It does not kink, stretch, or wear so as to change its length. The steel tape may be obtained in lengths varying from 3 feet to 1000 feet. These tapes may be marked or graduated in any form desired. The two common methods of marking the tape are by either etching the surface with acid, or stamping the marks on solder placed on the tape at the desired places. A tape Fig-. 2. A metallic tape. This tape has brass or cop- per wires woven into it lengthwise. SURVEYING 21 3. A steel tape wound on a reel. 100 feet long is usually termed the engineer's tape, and either this length or the 50 foot tape is the most convenient. The average width of the steel tape is 5-16 of an inch, and the thick- ness about .02 of an inch. Short tapes are arranged to be carried in metal or leather cases, but longer tapes are carried either on reels or are "thrown" into a coil from which they can be unwound without danger of kinking. Arrows, or Marking Pins. For mark- ing points temporarily while measuring with a tape or chain, arrows, or marking pins, are used. These are made of stout wire, pointed at one end, with a large eye or ring at the other. In order that the pins may be easily found in the grass or leaves, a piece of colored cloth should be tied to the rings. Eleven pins are required for a com- plete set, and are best carried on a ring Arrows, with a spring catch. Range Poles or Flagstaffs are used to locate points in establishing a line. They are rods or poles usually 6 to 10 feet 'long, made of wood or iron, pointed so as to be easily planted in the ground, and painted red and white alternately in foot sections. Flagstaffs should be placed directly over the points they are to mark, and great care should be used to plant them truly vertical. Much skill may be attained by practice in estab- lishing lines with flagstaffs, and this skill will be found very useful in laying out fields, fences, etc. 4. or pins. 22 AGRICULTURAL ENGINEERING The Care and Use of Chains and Tapes. The chain is folded by starting at the middle and folding in the two halves at the same time. It is opened by holding the two handles in one hand and throwing out the chain with the other. The steel tape is wound on a reel or thrown into a coil, the lat- ter method requiring some practice and skill to prevent kinks. Chains and tapes are used in measuring horizontal distances; and for this purpose they should be held horizontal, or level, when meas- uring, not parallel to the surface of the ground. The chain or tape should be pulled taut enough to overcome the shortening due to the sag. Where distances are to be obtained with great accuracy, the chain or tape should be tested often over a known fixed distance to determine the amount of pull necessary to bring it to the true length. Chains in constant use re- quire frequent adjustment for wear. Each pin should be so placed that its thick- ness will not be added to the length of the chain. Care should be taken to set the pins vertical. When chaining up or down slopes, one end of the chain must be held high to make it level, when it becomes necessary to transfer a point from the elevated end vertically to the ground. This can best be done with a plumb-bob and string, and a wooden when this is not at hand a pin may be dropped range pole. from the elevated end of the chain or tape and the point where it strikes the ground noted. In chaining practice, the man leading is called the head chainman, and the other the rear chainman. In beginning a measurement, the rear chainman marks the starting point with one of the eleven pins in the set, and gives the remain- SURVEYING 23 ing ten to the head chainman, who counts them. The head chainman then leads away with the chain or tape toward the point to which the distance is to be measured. When the rear end of the extended tape is near the starting point, the rear chainman calls "chain" or "tape," as signal for the head chainman not to go too far. The chain is then stretched full length, and the rear chainman lines the front chainman with the objective point by motioning with his head or other- wise indicating the direction he should move. When the head chainman has the chain in line, the rear chainman calls "stick," indicating that he has the chain to the pin. The head chainman then pulls the chain tight, and sets a pin, calling "stuck." The rear chainman pulls the rear pin, and both men move ahead and repeat the operation from the second pin; and so on. When the head chainman has placed his ten pins, he calls "tally," and waits for the rear chainman to walk forward to him and give him the ten pins he has collected. Pacing. The ability to estimate distances accurately by pacing is often useful. Skill may be developed by pacing known distances until the length of the individual pace is determined and can be regulated. QUESTIONS 1. What instruments are needed in making a practical survey of a tract of land where the boundaries are known? 2. Describe the Gunter's chain. 3. Recite the four tables used in measuring surfaces. 4. Describe the differences in tapes. 5. Describe the use of range poles. Of marking pins. 6. How is the chain cared for? The steel tape? 7. Describe the process of chaining. 8. In what way will the ability to estimate distances by pacing be useful? CHAPTER III FIELD METHODS Making Chain Surveys. For many practical purposes a survey made with the tape or chain alone will be quite satisfactory. To make such a survey for area, the land is divided into rectangles or triangles, or both. The areas of any of these may be easily calculated when the length of each side is known. Making Notes. In all surveys, all figures, notes, and sketches should be sys- tematically recorded in a suitable book, and these go to make what is called field notes. From these notes the map is later made and the areas cal- culated. The most simple method of making field notes is to make a free- hand sketch of the field as nearly correct as the eye can determine. All corners should be designated by letters and the same marked on the sketch, which is used as a guide. All distances between corners should be recorded, not only in the sketch, but also in suitable columns. The points where fences, streams, and roads are crossed in measurement should be noted on the sketch. If the tract surveyed is so large that the sketch is likely to become confused, the entire SURVEY or FIELD A BCD WITH TAPE AB BC CO DE EA BE SO 14 ISO BOO £50 ISO 110 155 Head chainman R.Roe Rear chainman 1. Do e Sept./ igii - J hrs- Cloudy and cool Used steel tape looft. Measured each side in turn once c A ~~~^^$: \ E Fig-. 6. A form for field notes. SURVEYING 25 tract may be sketched on one page, and details of certain parts on other pages. All field notes should be carefully recorded in a well- bound, durable, and convenient field book. The standard field book has pages about 4 by 7 inches, ruled in any one of the several forms of ruling, and is substantially bound. The notes should be neatly made with a hard pencil in order that they will not blur with use. In the sketches, the cus- tomary symbols employed in map making may be used. These will be described later. Field Methods. In making a chain survey, it is to be remembered that since angles are not measured, more meas- urements will be required. Many fields are rectangular, and their measurement is correspondingly simple. When the angles are not right angles they may be determined by measuring three sides of a triangle laid off in the corner, making two sides or the legs of the triangle coincide with the sides of the field. Marking Points in a Survey. In making a survey all the important points should be marked for future reference. In laying out fields and lots, some permanent mark should be set at the corners. If a corner post is not used, a stone or a block of concrete should be set in the ground and a cross chiseled on the surface to indicate clearly the point. Stakes of durable wood may be used to good advantage. The exact point may be indicated by driv- ing a tack in the top of the stake. A stake two inches square is often i mi r- i i , i *l.- j.1 Fi %- "'■ Sketch showing used, ihe field notes describing the how a line may be laid oft i ,. p ,-, • , i i i i at right angles to another location ol these points should be at a point a. 26 AGRICULTURAL ENGINEERING complete and clear enough to make it easy for anyone to find the corners again at some future time. PROBLEMS FOR PRACTICE (In order to carry out the following problems it will be necessary to be provided with equipment consisting of tapes, pins, and range poles.) 1. With chain and range poles lay off a right angle. Note. 3, 4, and 5 feet, or corresponding multiples of these dis- tances, are sides of a right angle triangle. Give the theorem of geometry upon which this is based. (Fig. .7). 2. Measure the distance between two points a thousand feet or more apart and check with the results obtained by the instructor. Random Lme_ -500' >< 50O' >k 5(Xf- True Line Fig. 8. Sketch showing' method of locating points on a desired line between two points not visible from each other from a random line. 3. Let each student pace this or some other known distance and determine the length of his pace. 4. Estimate certain distances by pacing, and then measure accu- rately with a steel tape. 5. Chain over a hill between two points not visible from each other. Range poles should be set at the points and then the chainmen with range poles should take such positions on each side of the hill as will enable each to see over the hill and past the other chainman to the range pole beyond. The chainmen then range each other in, mak- ing several trials. 6. Chain between two points when the view is obstructed by woods or other objects. To accomplish this, run a trial or random straight line as near as possible to the distant point, leaving fixed points at known distances. Upon finding the error at the terminus, correct all other points into line a proportionate amount. Then the desired line may be chained. SURVEYING 27 7. Determine the distance to a visible but inaccessible object. Use two similar right-angled triangles. Fig. 9. 8. Prolong a line beyond an obstacle. There are several ways to accomplish this, but the use of similar triangles is the only method suggested. Let A B be points in the line to be prolonged beyond O, an obstacle. Make A B C a right-angled triangle. Prolong A C to F, making C F equal A C, and C E equal E F, and B C equal C D. Extend D E to I, making DG and G I equal to A C, also extend F G to H, making G II equal F G. Then H I are points in the extended line AB. Fig-. 9. Sketch showing method of measuring to an inaccessible point. Sketch showing method of extend- f a line beyond an obstacle. 9. Make a survey of the lot on which the schoolhouse stands, locating buildings, etc. 10. Make a survey of the home farm or a part of it, as assigned by the instructor. 11. Make a survey of a lot or a field having an irregular side, by taking offsets at regular or irregular intervals, dividing the field into trapezoids. (See method of calculating areas of tracts with irregular sides) . QUESTIONS 1 . How is a tract of land divided in making a chain survey? 2. What care should be taken in making field notes of a survey? 3. What care should be taken in marking permanent corners? CHAPTER IV MAP MAKING Uses of a Map. When a survey of a farm or other tract of land has been made, a map should be drawn to show the location of the buildings, fences, lots, roads, and of the trees, streams, and other physical features of the land. A map enables the mind to grasp the facts in a way not possible with the field notes alone. Although not generally practiced, a good map of the farm can be used advantageously in directing the work of the farm. This map should also serve as the means of recording the location of drains and water pipes placed beneath the surface of the ground. If the fields are numbered and the map placed in the office or dining room of the home, it may be used as a basis in planning each day's work. The map will set also forth in a very forceful way any inconvenience in the arrangement of the buildings or fields. The Final Map. The final map is made from the data recorded in the field book. As has been said, a sketch map usually forms a very helpful part of the field notes. The final map must be drawn carefully as well as accurately, and should be made as durable as possible. Drawing Instruments. The equipment for making maps may be quite extensive, yet the essential instruments are not many in number nor are they expensive. A good outfit includes the following: A drawing board of soft wood and about 20 by 30 inches in size, a T square, a triangle, a scale providing at least 10 and 50 divisions to the inch, a ruling or right-line pen, a compass for drawing circles, a bottle of SURVEYING 29 India ink, and a pen, a pencil, an eraser, thumb tacks, etc. A bottle of carmine ink is convenient but not necessary. When angles are to be plotted a protractor is quite necessary. A good quality of drawing paper should be used, or one that will stand reasonably hard usage in folding and handling. A good quality of paper is known as bond paper, and a con- venient size of sheet is 18 by 24 inches. A drawing made on this bond paper may be reproduced by blue printing, a process similar to the making of photograph prints from Pig'. 11. A set of drawing' instruments, consisting" of a drawing board, a T square, a triangular scale, two triangles, a protractor, a case of instruments, an irregular curve, paper, ink, tacks, etc. This sft is more complete than is required for map making as indi- cated in text. negatives. The process is rapid, requiring but a few min- utes, and the cost of the blue-print paper is but a few cents per yard. A better print can be obtained, however, from a drawing made on tracing cloth, which is thin and so prepared as to make it practically transparent. Where expensive 30 AGRICULTURAL ENGINEERING maps are to be prepared, one of the heavy, serviceable papers, like Whatman's hot-pressed paper, is desirable. Making the Map. In making a map, the proper scale to use, that is, the ratio between the actual distances in the surveyed tract and corresponding ones for the map, must first be decided upon. In the case of an average-sized farm, 100 or 200 feet to the inch is a convenient scale. The larger the area or the smaller the maps the greater will be the dis- tance represented by one inch on the map. If the scale, (meaning the instrument used for measuring) be graduated so as to give 50 divisions to the inch, it will be easy to use with any of the ratios proposed. For instance, suppose the ratio of 100 feet to the inch be adopted, then one division on the scale will represent 2 feet ; and if 200 feet be adopted as a ratio, then one divi- sion will equal 4 feet, etc. The handling of the drawing instruments mentioned is simple. The head of the T square, when held by the hand against the straight edge of the drawing board, will permit the drawing of parallel lines. By holding the triangle against the blade of the T square, all vertical lines may be drawn accurately. The ruling or right-line pen is used in drawing straight lines on the final map with the India ink. The first operation to perform in preparing a map is to lay off the boundary of the tract to be mapped. Then the location of other features may be added. Angles may be plotted in by the use of the protractor, if angles have been 12. Laying out a tri- the length of the three SURVEYING 31 read. The use of instruments for measuring angles will be described later. If measurements have been made to determine angles, these angles may be laid out with the aid of the compass, setting this instrument with the scale and describing circles whose radius is equal to the length of the sides of the triangle. The map should first be made with a pencil, and then, after every feature has been drawn, should be inked in. Common Topographical Signs. A topographical map is one which gives the general character of the land surface, SlngleTrack. : -L.. ' -, i ' " 7 if Double Track. Second ry ■• Private or Farm. Wire Fence. "Rai7*~* _ * _ Picket^ ;• Unfenced Prop. Line. Stream. Railways. Roads. Boundaries 0000000 00 000 ooooooo 000000 "-- : ' ■ ; -. h H i L ii \: 1 ^ /' /a * 7 « \lfl Cultivated Land. Windbreak. Contour Contour & Q Q <3 & © © <3> © © © @ ® & © ^ ■> o o & o e> Lawn. Orchard. DeciduousTrees. Evergreens. Fig. 13. Conventional topographical signs. showing where there are roads, buildings, forests, swamps, etc. To facilitate the making of such maps, it is customary to use certain symbols or methods of representing certain conditions of the surface. A general use of certain symbols to indicate certain things has resulted in their being known 32 AGRICULTURAL ENGINEERING as conventional topographic signs. It is not sufficient, how- ever, that these conventional signs alone be used, but should be supplemented with notes. Lettering. Maps made by professional draftsmen or engineers have all notes and titles neatly lettered in. The ability to do lettering quickly and neatly is a part of the train- ing of the engineer. Letters for titles are often made by the abcdefghijklmnopqrstuvvJXyz IB 3 456 7 8 9 A BCDEFGHIJKLMNOPQRS TU V W X Y Z Inclined Lettering, for Description. abcdefghijkln-inopqrs + uvwxyz ABCDEF GHIJKLMN0PQR5TUVWXYZ IS345 678 9 Upright Lettering ,f or Captions. Fig. 14. Good styles of free-hand lettering. use of instruments, but on most maps the letters must be made with a form of the writing pen, the only instruments used being the T square and triangle with which the guide lines are drawn, to assist in making the letters even and of uniform height. While it is not best to attempt to duplicate the work of the professional engineer, it is desirable that all maps be of as neat appearance as practical; and few things add to or detract from the appearance of a map quite so much as lettering. The best lettering is that which is simple and easily and quickly made. A good alphabet is furnished in Fig. 14, and is a form of lettering now in general use. The beginner should first pencil the letters on the map; and when SURVEYING 33 an arrangement of the notes is found which is adapted to the map, they should be traced with drawing ink. Although not absolutely essential, it is suggested that all maps be lettered in the customary way. Field No. 1 Field No-E 35. A. 35 A Pasture 15 A Field No. 3 Field No. 4 35 A 35 A ^tf' D *aal II Ivn. Fig. 15. A farm map. QUESTIONS 1. In what way may a farm map be used? 2. What is the purpose of a sketch map? 3. What drawing instruments are necessary for map making? 4. What kind of paper should be used in making a map? 5. Describe the making of a map. 6. What is the use of conventional topographical signs? CHAPTER V COMPUTING AREAS Method of Computing Areas. One of the primary objects in making a farm survey is the determination of the areas of fields and plats. The computation of areas as here described is dependent upon a knowledge of mensuration and geometry. The general plan to be followed is to divide the tract into simple or primary figures whose areas can be easily calcu- lated. These familiar rules of mensuration will now be reviewed. Rectangles. If a tract of land is rectangular in shape, its area is found by multiplying its length by its breadth. Triangles. If a piece of ground is in the form of a tri- angle, its area may be obtained by either of the following rules: (1) If the length of one side, and the perpendicular distance from this side to the opposite angle, or the altitude of the triangle, are known, the area is one-half the product of the known side as the base, times the altitude. (2) If all three sides of a triangle are measured, then the area may be obtained by adding the lengths of the three sides and dividing the sum by two; from this half sum subtract the length of each side in turn; multiply together this half sum and the three remainders; the square root of the product equals the desired area. Thus, if a, b, and c are three sides of a triangle, , a + b + c ,. and s = , then area = [/ s (s-a) (s-b) (s-c) SURVEYING 35 Parallelogram. (Fig. 17.) The area of a parallelogram, a four-sided figure with opposite sides parallel, is equal to the product of one of its sides and the perpendicular distance be- tween it and the opposite parallel side. Trapezoid. (Fig. 18.) This is a four-sided figure with two sides par- allel. The area is equal to the pro- duct of one-half the sum of the parallel Fis ' 1S " sides by the perpendicular distance between them. a+b Area Xh. where a and b are the two parallel sides, and h the perpendicular distance between them. Trapeziums (Fig. 19) are quadrilateral figures, no two of whose sides are parallel. A practical way to obtain the area of a field of this shape is to measure a diagonal dividing the field into two triangles whose areas may be calculated. It is to be noted that averaging opposite sides and taking their product will not give the area. Area abcd = area ACD+area abc. Figures With Many Sides. First Method: (Figs. 20 and 21.) A many- sided piece of land may be likewise divided in triangles and its area ob- tained in the way described for tra- pezium. The triangles may be formed about one of the corners of the figure, or about a point wholly within the 36 AGRICULTURAL ENGINEERING Fig. 21. area. It is to be noted that if a point within is taken as the apex of all the angles, it would be necessary to measure, either all three sides of each separate tri- angle, or one side of each as a base, and the altitude. Second Method: (Figs. 22 and 23.) The area of a many-sided figure may be obtained by dividing the field into parallelograms formed by dropping a perpendicular from each corner to a base line projected either across the field or on one side. It is to be noted that all parallelo- grams which are entirely outside of the field are negative areas, and their sum should be subtracted from the sum of those having a part of their area inside of the field. Figures With Irregular Sides. First Method: The area of a field with an irregular side like that formed by a stream may be obtained by considering the irregular side to be formed of short straight lines, and measuring offsets, or per- pendiculars erected from a base line to points in this Fl§ ' 24- broken line so as to form trapezoids, whose areas are easily found. SURVEYING 37 Second Method: If the side of the irregular field is not of such a character as to be readily divided into large trapezoids, then the offsets may be taken at regular intervals along the base line. If d be the regular interval between offsets then the area of the trapezoid whose sides are h and h ' is equal to one-half their sum mul- tiplied by d, or Area ABCD = J/2d (h-\-h') PROBLEMS 1. What is the area in acres of a rectangular field whose length is 1320 feet and whose width is 347^ feet? 2. How many acres in a field 80 chains long and 13.25 chains wide? 3. What is the area in square feet of a triangular piece of ground, if the length of one side is 339 feet and the altitude on this side as a base is 92 feet? 4. The length of the sides of a tract of land in the form of a tri- angle are 220,310, and 343 feet. What is the area in acres? 5. The four sides of a trapezium are 420, 417, 380 and 375 feet taken in order around the field, the diagonal from the corner between the 417 and the 380 foot sides to the opposite corner is 528 feet. Find the number of acres in the tract. 6. Find the acre area of a road 66 feet wide and 3960 feet long. 7. Find the area in square feet of a tract of land with an irregular shaped side if offsets taken at the regular interval of 50 feet are 0, 25, 30, 28 and 50 feet, respectively. 8. How many rows of corn 3 feet 6 inches apart can be planted in a field 20 rods wide? How many hills of corn 3 feet 6 inches apart will there be in the field if it be 80 rods long? 9. How many apple trees 20 feet apart may be planted in a 1-acre tract in the form of a square? Try a different arrangement of the trees. 10. At this point the student should be prepared to take up the problem of surveying, mapping, and calculating the area of certain tracts of land, as the school house yards, lot, field, or even whole farms CHAPTER VI THE UNITED STATES PUBLIC LAND SURVEY In order to facilitate the survey, location, and designation of the lands in the United States, Congress in 1785 adopted a system since known as the United States Rectangular System of Public Land Surveys. This system has been modified from time to time but remains substantially as first adopted. The earth's surface is like that of a sphere, and it would be expected that in attempting to lay out the surface into rectangular areas one would encounter many difficulties. Yet these difficulties have been very satis- factorily met. The squares of this system are bounded on the east and west by true meridians of longitude, radiating from the north pole, and on the north and south by chords of parallels inter- secting such meridians. A principal meridian is chosen in each land district, and from this meridian a base line is run east, west, or east and west, from what is called the initial point. Standard parallels are run east and west from the principal meridian at intervals of 24 miles. These standard parallels are often T.4N. R.4-W. T.4N. R.3W. T.4N. R.SW. T.4N. RJW. 1 T.3N. R.4 W. T.3N. RJW T.3N. R.ew. T.JN R.IW. T.SN. RAW. T.3N. R.JW. T.SN. R.2W. TEN- R.I W. TIN. R.4W. TIN. RJW. T.IN. R.ew. T.IN. R.IW. Bas •e Line Initial Poinl 26. Showing bering the division and num- of townships. SURVEYING 39 called correction lines. Guide meridians are run north from the base line and from the standard parallels at intervals of 24 miles. These blocks of land are successively divided into townships six miles square and then into sections ap- proximately one mile square. Townships. The townships lying between two consec- utive meridians six miles apart constitute a range, and the ranges are numbered from the principal meridian, both east and west. The townships in each range are numbered both north and south from the base line. Thus if a town- ship lies 18 miles west of the principal meridian and 12 miles north of the base line, it is de- scribed as Township (Twp.) 2 N., Range 3 W. Sections. Each town- ship is divided into 36 sections of 1 square mile, or 640 acres more or less, the exact areas being- subject to the conver- gence or divergence of Fig. 27 the meridians, which amounts to about a foot for each mile. Sections in all of the more recent surveys are numbered, beginning with the section in the northeast corner of the township as No. 1, and proceeding as indicated in Fig. 27. Subdivisions of Sections. Each section may be divided into one-fourth section, or 160 acres, or into still smaller divisions of 80, 40, or 10 acres. Each of these divisions may be described by its location in the section. Thus a quarter section of 160 acres may be the N.E.K, S.E.^, S.W.K, or s 5 4 J 2 1 7 3 9 IO » 12 IS 11 16 « /■*- 13 19 20 21 22 23 24- 30 29 28 £1 26 25 31 JZ JJ 34- Z5 ■36 The numbering of the in the township. 40 AGRICULTURAL ENGINEERING the N.W.K of Sec— Twp— Range— . An 80-acre tract may be the E.y 2 , W.y 2 , S-34 or N.3^ of etc The 40- acre and smaller tracts may be described in a similar manner. Monuments. In making the original surveys, the gov- ernment surveyors left what are called monuments to mark the location of principal corners. These monuments were usually made of stone with suitable marks to identify them, but in some instances only wooden stakes or heaps of earth were used. Surveys by Metes and Bounds. Before the adoption of the rectangular system of A/. W % 160 A N.CK, NW!x 40A. S.\N.E.k 80 A 5e T 4 N.R.I VI. land surveying, the lands in the United States were sur- veyed by describing fully the boundaries, and it was not practical to change to the new system where land had been so surveyed. This sys- tem is still used to a certain extent to describe small tracts of land even when the rectangular system might be used. Resurveys. It is not the purpose of this text to include directions for surveying units larger than the farm, and it does not attempt to give directions for a resurvey of the loca- tion of the corners of a certain tract, yet some of the impor- tant features of such a survey may be mentioned. One of the most important considerations is that when the boundaries of the public lands established by the authorized government surveyor are approved by the surveyor general, and accepted by the government, they are unchangeable. This is true whether the corners were located where they Fig. 28. Divisions of the section. SURVEYING 41 were intended to be or not. Future surveys may be made to further subdivide the tract, but as long as the original corners are known, no additional surveys can change them. If the corners become lost, a resurvey may be made to locate them, not where the corners ought to be according to the system, but where they were first located. There are many considerations and points to be taken into account in the re- storation of lost and obliterated corners and subdivisions of sections, and it is advised that this be left to the pro- fessional and authorized surveyors. QUESTIONS 1. What was the purpose of the United States rectangular system of public land survey? 2. What is the general plan of this survey? 3. Explain how the land is divided into townships and sections. 4. How are townships numbered? 5. How are sections numbered? 6. Explain how sections are divided and the parts described. 7. How were comers marked in the original survey? 8. Describe the process of surveying by metes and bounds. 9. What is the purpose of a resurvey? CHAPTER VII INSTRUMENTS FOR LEVELING So far our discussion has been confined to instruments used for measuring horizontal distances, or those necessary to obtain areas. In farm practice, however, it is necessary in connection with drainage practice, road construction, etc., to determine vertical distances, or the height of one point above another even though these points be at some hori- zontal distance from each other. DEFINITION OF TERMS A level surface is one that is perpendicular to a plumb line at every point in the surface. It is not a plane nor is it a true oblate spheroid, owing to the fact the earth is not a homogenous body and the center of mass does not conform with the center of form. A level line is one that lies wholly within a level surface. A leveling instrument is one by which a level plane or a level line may be accurately determined. The three appli- ances upon which leveling instruments depend are the plumb line, a tube filled with liquid, and the bubble tube. A datum plane or a datum is the initial plane to which the height or elevation of points may be referred. A datum plane in common use is that of sea level. The elevation of a point is the distance of the point above or below the datum plane. A leveling rod is a graduated measuring rod or staff used for measuring vertical distances between a point on which the lower end of the rod may rest and a line indicated SURVEYING 43 by an instrument. A leveling rod which has a sliding disk or target which may be raised or lowered until the center lies in the line indicated by the leveling instrument, is called a target rod. A rod which may be read from a distance or from the leveling instrument is a speaking rod. Leveling rods are graduated to feet, and tenths and hundredths of a foot. In work requiring extreme care, the target may be so made as to be read to one-thousandths of a foot. Bench marks are permanent objects whose elevations are known or assumed, and which may be used as reference marks fcr the elevation of other points. The Plumb Line. The plumb line is per- haps the simplest and most generally used of the leveling instruments. Even the most expensive instruments use the plumb line to locate the instru- ment directly over a given point. Provisional levels may be taken by means of a combination of the plumb line and steel carpenter's square, and the difference in the elevation of points not far apart may be thus obtained. This instrument may be used not only in laying drains but also in road construction to determine the grade of the road and the slope to the side ditches. The U Tube or Water Level. This instru- ment depends upon the principle that a liquid " seeks its level." It consists in two glass tubes fastened vertically about three feet apart on a suitable arm and connected with Fig. 29. Level- ing rods: the one on the right is a non-speaking rod, known as the New York; and the one on the left is a speaking rod, known as the Philadelphia. 44 AGRICULTURAL ENGINEERING me of SiGht Height of Liquid .s-Bo/ts. Corks to be Used When L e vel is Carried a tube. Water is then poured in until it appears at a con- venient height in both glass tubes at the same time. The surface of the water in each of the two tubes gives two points in a level line, which may Vr-corks J , CLJ , a be extended to a distant leveling rod by sighting- over the surface of the liquid. A water level may be made as shown in Fig. 31; A and B are short lengths of glass tubing attached to a board, about three feet apart, and connected on the lower sides with a length of rubber tubing. For field use, the board is bolted to a staff which may be pushed into the ground to hold the instrument erect, and corks are provid- ed for the upper ends of the tubes to prevent loss of the liquid while the instrument is being carried. When leveling, these corks should be removed. The bubble tube is the basis of nearly all leveling instruments. It consists of a round glass tube bent so that the upper inside sur- face is an arc of a rat^ea^R^^^J^M^^^-^^^- circle lengthwise, or on a longitudinal sec- tion. This tube is sealed at each end and nearly filled with ether, the remaining space being filled with the vapor of the liquid. The upper surface of the tube is usually graduated V Fig. 31. A home made water level. bubble tube. SURVEYING 45 A carpenter's level sights attached. with or marked to indicate clearly the position of the bubble in the tube. If the inside of the bubble tube is truly circular length- wise, then as the bubble tube is held so as to bring the con- vex side of the tube up, it is plain that the bubble will come to the highest point. This being the case, a line tangent to the curvature of the tube at this point is a level line regard- less of the part of the tube in which the bubble may lie. If the bubble tube is attached to a frame and placed on two supports and one of these supports is raised or lowered until, as the frame is reversed on the supports, the bubble will occupy the same position, these supports are both in a level line, provid- ing the identical points in the frame come in contact with the supports in each case. Furthermore, the points on the frame will be in a level line when the bubble is brought into the position described. Thus the carpenter's level, used for leveling buildings, is made. If sights are provided on the level, the level line so obtained may be extended to a greater distance. A line tangent to the bubble tube on its inner surface at its center as indicated by the marks on the tube is known as the bubble axis. If the bubble tube be revolved about a line perpendicular to the bubble axis, the bub- ble axis will describe a level surface. The Level. The instrument used generally by engineers Fig. 34. An inexpensive farm level with horizontal circle for turning off angles. 46 AGRICULTURAL ENGINEERING for determining the difference of elevation between two points is known as the level, and involves primarily the ele- ments just described, — the bubble axis, a line of sight paral- lel to the bubble axis, and a vertical axis perpendicular to the bubble axis about which it may be revolved. To assist in extending the line of sight, leveling instru- ments are provided with telescopes. The sights in this case are provided by cross wires or cross hairs, set in the tele- scope. ■J Fig. 35. A level known as a Wye Fig. oG. A "dumpy" level, level with horizontal circle and com- pass. THE ADJUSTMENTS OF THE LEVEL The Need of Adjustment. Accurate and rapid work cannot be done with a level unless it be in proper adjustment. Even the best instruments will not remain in adjustment indefinitely, and tests of their condition should be made often. In practice some of the best engineers make it a rule to test their instruments every day. Everyone who uses a level should know how to test and adjust it. Its adjustment is not a difficult matter, yet it requires some study to master the methods used. Every instrument maker of repute will fur- nish full and complete directions for adjusting each instru- ment of his manufacture, and these directions should be given preference over general directions applicable to all SURVEYING- 47 instruments. There is more than one method of making- certain adjustments, but only one will be explained here. As has been stated, there are three elements in a level which should be kept in proper relation: namely, the vertical axis, or the line about which the instrument can be rotated ; the bubble axis, which is a level line; and the line of sight. The last two must be parallel, and the first perpendicular to both. If the line of sight be inclined upward, it is obvious that all rod readings will be too great, and the error will be proportional to the distance of the rod from the level. If the line of sight be inclined downward, all readings will be too small. If the length of sights, or the distance between the level and the stations, be equal in making front and back sights, the error in each case will be the same, and the rela- tive elevation of the stations will be obtained without error. For this reason it is desirable to make fore sight and back sight distances equal. The adjustment making the vertical axis of the level and the bubble axis perpendicular, is a matter of convenience, for this will cause the line of sight to describe a plane con- taining all the level lines through the instrument. This means that it will not be necessary to change or "level up" the instrument in sighting in different directions. First Adjustment To make the vertical axis of instru- ment perpendicular to the bubble axis: Adjust the bubble tube to the vertical axis as follows: Level up the instrument, bringing the bubble to the center of the tube, turn the telescope through 180 degrees, and, if the bubble changes position, raise or lower the adjustable end of the tube until the bubble is brought half way back to its former position. Level the instrument again and repeat the operation; and if the bubble moves in the tube, make further adjustments. Continue this process 48 AGRICULTURAL ENGINEERING until the bubble does not move in the tube as the telescope is turned about the vertical axis. Second Adjustment. To make the line of sight parallel to the bubble axis: Select a level piece of ground for the work, and locate three points in a straight line, 100 feet apart. At one end point (Sta. A) drive a hub, at the mid-point locate the level and take a reading on a rod held on the first hub with the instrument carefully leveled. Turn the instrument in the opposite direction, and, after leveling carefully, drive a hub at the second point (Sta. B) until the same rod reading is obtained as at Station A. These two stations now have the same elevation, because any error of the instrument will be the same in both cases. Now bring the instrument near Station A (two or three feet off) and adjust the line of sight until the same rod readings are obtained on both stations. The rod on Station A may be read by looking through the instrument in the reverse way and locating the line of sight on the rod with the point of a pencil. After adjusting, the operation should be repeated as a check. QUESTIONS 1. Define a level surface. A level line. A leveling instrument. A datum plane. 2. What is meant by the elevation of a point? 3. Describe a leveling rod. What is the difference between a speaking and non-speaking rod? 4. How are leveling rods graduated? 5. What is the purpose of a bench mark? 6. Describe the plumb line. How may it be used to determine a level line? 7. Describe the construction of the water level. 8. Describe the bubble tube and its use in leveling. 9. Describe the construction of the engineer's level. 10. What is meant by the "line of sight"? 11. Describe the fundamentals of the adjustment of the level. CHAPTER VIII LEVELING PRACTICE Differential Leveling. Differential leveling is the name given to the process of finding the difference of elevation of two or more points at some distance from each other, with- out reference to intermediate points except those required temporarily in carrying a line of levels between the points whose difference of elevation is required. Differential leveling is like profile leveling, except that elevations are not taken at regular intervals on the surface. It is desir- able, however, to make the sights or the distances between the instrument and rod of equal length, as this tends to equal- ize errors which may exist in the adjustment of the instru- ment. Profile Leveling. Profile leveling is for the purpose of obtaining the elevations of the surface of the ground. It is especially important in this connection, as profile leveling is required in the laying out of land drainage systems. Leveling. The process of leveling, or in other words the performance of the field work in determining the elevation of points on the surface of the ground, is comparatively simple, yet it is highly important that the work be done accurately and that a full record be made of the Work. To run a line of levels, a bench mark, or a permanent point of reference, should be chosen from which a start is made. The importance of the bench mark is all the more magnified with an increase in the size of the system of levels. If the elevation of the bench mark is not known, it must be assumed. For convenience it is usually taken as 10, 20, or 100 feet, 50 AGRICULTURAL ENGINEERING depending somewhat upon whether the levels are to be taken above or below the elevation of the bench mark. As for field surveying, a substantial field book should be provided for level notes. A book of the same size as previ- ously suggested is de- sirable, with ruling as showninFig.37. The elevationof the bench mark is placed in the second column oppo- site the entry B. M. in the first column. Set the instrument up half way between the bench mark and the first point whose elevation is desired in the line of levels. This point is called Station A, and is entered as such in the first column of the field book. After the instrument is Line of Levels. Sta B.S. HI. r.s. Elev. B.M. 6.50 16.50 10-00 A 1.00 19.40 4.10 18.40 B 4.05 21.35 e.io 11.30 C 3.60 11.15. A form for level notes. Fig. 38. Sketch illustrating the levels of Fig. 37. brought into a level position, the rodman holds the rod in a vertical position over the bench mark, and the levelman takes a reading by, over, or through the instrument to the rod. The reading thus obtained is the distance of the line of sight above the bench mark (B. M.), as the rod is graduated from the bottom up and the line of sight is a level line. This SURVEYING 51 reading is called a back sight (B. S.), and if added to the elevation of the bench mark will give the elevation of the instrument, or the height of instrument (H. I.), as generally designated. The first B. S. thus obtained is entered in the notes in the second column, opposite the B. M. elevation in the first. This B. S. plus the elevation of the B. M. is entered in the third column under the head of height of instrument, or H. I. Thus if the elevation of the B. M. be assumed as 10.00 feet, and the B. S. reading of the instrument on this point be 6.50 feet, the H. I. will be 16.50 feet. Now if the instrument be turned so as to extend the line of sight in the direction of the first point in the line of levels (Sta. A) and a reading be taken in the same way, the reading on the rod will be the distance of the elevation of this point below the line of sight. The reading is called a fore sight (F. S.), and is entered in the fourth column opposite Station A., on which the reading was taken. If this fore sight read- ing be subtracted from the elevation of the line of sight (H. I.), the elevation of Station A will be obtained. For instance, suppose the F. S. reading thus obtained is 4.10 feet, then H. I., 16.50 feet, minus the F. S., 4.10 feet, equals 12.40 feet, the elevation of Station A, which is entered in the proper column opposite Station A. To continue the line of levels, the instrument is moved to a position midway between Station A, and Station B, and, after the instrument is leveled, a B. S. reading is made on Station A. This reading added to the elevation of Station A gives a new H. I., from which the F. S. reading on Station B is subtracted to obtain the elevation of Station B. Thus the process is continued until the elevations of all the points in the line of levels are obtained. It is easy to see how additional readings may be taken with the same height of 52 AGRICULTURAL ENGINEERING instrument and thus obtain the elevation of several points between A and B. This is done in practice. It is to be noted in this connection that back sights are rod readings on stations or points whose elevations are known, and fore sights are readings on stations whose elevations are not known. Stations on which back sights are taken are generally known as turning points. Stakes. It is generally best that all stations be marked with a stake driven down close to the ground, on which the /.t ,7 ,*« ,2* .'2s- ™ /f ? leveling rod may be placed; US- as_ '22. //-? j-/5 //.*? / and turning points should always be so marked and identified. Leveling a Field. It is sometimes advisable to obtain levels at regular intervals over an entire field. This is accomplished by laying the field off into squares, usually by the chain or tape. The corners of the squares are marked with stakes made of lath and the elevation of the top of the ground is taken at each corner, as shown in Fig. 39. The various corners of the squares are designated by lettering in one direction and numbering in the other as shown in the figure. Contour Maps. Lines may be drawn over the map of the leveled field to indicate points of equal elevation. Such ' lines are called contour lines. They offer a very satisfactory means of studying the surface of the ground, and a map so prepared is especially useful in laying out drainage systems. Horizontal Circles for Levels. Many levels are pro- vided with horizontal circles or scales, graduated in degrees //.f /// 6 Fig. 39. Plat showing how levels may be taken over an entire field. The stations are indicated by letter and numbers, as B2, etc. SURVEYING 53 and fractions of degrees, which enable the angle between lines of sight in different directions to be measured. This device is especially useful in laying off right angles, as well as in obtaining the angle between two sides of a tract of land, and between lines of drains in laying out drainage systems. The Compass. A level may be provided with a compass box containing a magnetic needle, which will enable the angle to be measured between any line of sight and the north and south as indicated by the needle. In construction, the mag- netic needle is a fine hardened piece of steel carefully balanced and hung on a delicate pivot and so arranged as to swing within a graduated circle. In order to protect the pivot while the instrument is being carried about, a little device is provided to lift the needle from the pivot. In most localities the needle does not point truly north and south, inasmuch as the magnetic pole does not always lie due north ; and furthermore, the location of the magnetic pole varies from time to time. If the true north is desired, it is neces- sary to make the corrections for the location of the magnetic pole. This variance from the true north, or meridian, is called the declination of the needle. In reading the needle, if no correction is made, it is customary to indicate that the reading is magnetic (Mag.). The Bearing of a Line. The direction of a line is called its bearing; in other words, the bearing is the angle that a line makes with the direction of the magnetic needle. If the direction of a line, beginning with the instrument, lies within 90 degrees to the right or the left of the needle, it is said to have a north bearing, or a northing; and likewise, if it lies within 90 degrees of the true south, either east or west, it is said to have the south bearing, or a southing. If the line lies to the east of north, it is also said to be east, and if to the west, it is said to be west, and is so designated following the 54 AGRICULTURAL ENGINEERING number of degrees indicating the angle of the line with the true north or south. Thus, a line in the right-hand quadrant is north and so many degrees east; as, N. 4° 37 . E. A line whose direction lies in the left-hand quadrant is north, and so many degrees west. The Transit. A surveyor's transit. It is not the purpose to include here instructions in the use of the transit. It is desirable, how- ever, to explain in a brief way !*» the instrument. The transit is a universal surveying instru- ment, and it is arranged for measuring horizontal and verti- cal angles, for determining the bearings by the magnetic needle, for leveling, for measuring dis- tances .by means of an attach- ment known as stadia wires, and for determining bearings from the sun when provided with a suitable solar attach- ment, and for many other lines of work. PROBLEMS The instructor should here arrange practice work in differential and profile leveling, and surveying with the horizontal circle and com- pass as far as the equipment provided will permit. QUESTIONS 1. What is meant by differential leveling? 2. What is the purpose of profile leveling? 3. Describe the process of leveling. 4. How should level notes be recorded in the field book? 5. What is meant by a back sight? Height of instrument? Fore sight? SURVEYING 55 6. Describe the process of leveling a field. 7. What is a contour map? 8. What is the use of the horizontal circle found on some levels? 9. Describe the compass. 10. What is meant by the "declination of the needle?" 11. What is the "bearing" of a line? 12. Describe the surveyor's transit, and for what may it be used? REFERENCE TEXTS The Theory and Practice of Surveying, J. B. Johnson. A Manual of Field and Office Methods for the Use of Students in Surveying, William D. Pence and Milo S. Ketchum. Plane Surveying, John Clayton Tracy. PART TWO— DRAINAGE CHAPTER IX PRINCIPLES OF FARM DRAINAGE Regulation of Soil Water. All vegetation is dependent upon the water or moisture in the soil for life and growth. Water dissolves the plant food in the soil and enables the plant to absorb and circulate it throughout its structure. Water also being transpired or given out by the plant, has a cooling effect, which counteracts the heat of the burning sun and prevents the plant from being withered or burned up. The amount of water used by plants for their most satisfactory growth is called the duty of water. Nature does not always supply water to the soil in quantities conducive to the most satisfactory growth of the plant. Often there is too little water, and many times there is too much. Land is drained for the purpose of relieving the soil of the surplus water. History of Drainage. The practice of land drainage runs back to a very early date. Some of the most interest- ing drainage projects of early times are the drainage of the fens of England and of Haarlem Lake in Holland. Land drainage by means of tile was introduced in Europe as early as 1620, but it did not come into general use until about 1850. Land drainage by tile was begun in the United States as early as 1835, by John Johnson, a farmer of Geneva, New York. These early drain tiles were made by hand. Tile- making machines were introduced about 1848, and from this time on, tile drainage increased rapidly. DRAINAGE 57 The area of the land in the United States which may be improved by drainage is still large. It is estimated by Mr. C. G. Elliott, formerly Chief of Drainage Investigation, United States Department of Agriculture, that there are yet 70,000,000 acres of land in the United States to be reclaimed by drainage. In addition to this there are large areas of land which could be made more productive and more valuable by drainage. Water in the Soil. The water in the soil may be classified as capillary water and hydrostatic water. "Capillary water Land needing' drainage. Typical conditions in northern Iowa and southern Minnesota. is that which covers the surface of the soil particles or grains as a film. It is the water in the soil which moves toward the surface by capillarity as the water at the surface evaporates. Hydrostatic water, or ground water, is that which fills the open spaces between the soil particles and which obeys gravity to the extent that it may be drawn off at the bottom 58 AGRICULTURAL ENGINEERING of a layer of soil if a suitable outlet be provided. When water exists on soil particles in a very finely divided state it is often called hygroscopic water. It is understood that capillary water, as defined, would include this hygroscopic water or moisture. Lands Requiring Drainage. In general, land having an Fig. 4 2. A good crop of corn on land which was a swamp the year before. excess of water over that required to furnish the best con- ditions for plant growth, needs under drainage. The exact conditions prevailing when an excess is present may be out- lined as follows: 1. Comparatively flat land in which water collects in basins or ponds from the higher surrounding land. DRAINAGE 59 2. Land kept continually wet by water appearing at the surface, having seeped or passed underneath the surface from land at a higher level. Such a condition is due to the action of springs. 3. Flat land underlaid with an impervious stratum of clay which prevents the water from sinking downward through the soil. Often this condition is represented by an old lake bottom. 4. Lands on which certain crops are grown, such as rice fields or meadow lands, to which irrigation water may be applied and removed at will. 5. Lands subject to overflow by rivers or tides. Kinds of Soils. The kind of soil to be drained must by all means be considered in connection with the planning of farm drainage. The amount of capillary water that the soil will hold varies largely with the fineness of the particles ; but a very fine soil will not allow water to pass through it quickly, and for that reason is designated as a retentive soil. There are other factors involved besides the fineness of the soil particles; for example, the working or mixing of a finely divided soil, such as clay soil, while filled with water tends to make it impervious, or water-tight. An open soil is one through which the water will pass quickly, and in which the pore space is not so finely divided as in a retentive soil. The volume of the space between the soil particles may be greater in the retentive soil than in the open soil, as this space generally increases with the fineness of the particles. Kinds of Underdrainage. All soils need under drainage, that is, the hydrostatic or ground water should be drawn off from the soil in some way. In most cases this under- drainage is provided by nature, and the ground is said to have natural underdrainage. The same may be true where the 60 AGRICULTURAL ENGINEERING surface of the ground is such as to give good surface drainage, as where the land has a good slope. However, where natural underdrainage is not provided, or where the surface is such as not to provide surface drainage, artificial drainage should be installed by means of tile drains or open ditches. Underdrains. Artificial underdrainage is generally accomplished by providing conduits, as open pipes, which will provide a free , and as far as possible, an unobstructed Fig. 4 3. An open drain. passage for the flow of the water through the soil. To secure the best results, these tile lines should have as much fall or slope as is practical in order to give a high velocity of flow to the water within them, and they should be as straight as possible and free from sags and obstructions. Open Drains. Open drains or ditches are simply free, open channels for the flow of water, where large quantities are to be cared for. They are' used where a system of under- drainage made of tile would not be practical. The advan- DRAINAGE 61 tages of closed or underdrainage, where it may be used, are obvious. It does not interfere with the cultivation of crops or other operations conducted on the land. Benefits of Drainage. Preparatory to the installation of the farm drainage system, must come the consideration of the benefits to be derived and an estimate to determine the advisability of the expenditure required, from the stand- point of an investment. Certain drainage systems may be justified as a protection to the health of the people of the neighborhood. This value cannot be computed in dollars and cents. Yet most farm drainage must be considered from the business standpoint. In this connection full considera- tion should be given to all of the benefits which may be derived from the improvement of the land by drainage. In general, it is to be expected that drainage will either reclaim the land for farming purposes or make it more productive. There are various ways in which land is made more produc- tive by drainage. Soil is Made Firm. When the level of the hydrostatic water is lowered, the soil above becomes more firm. Thus the wet marshy field in which a horse would mire may be made so firm by drainage as to permit a team and load to pass over it safely. Soil is Made of Finer Texture. It has been proven con- clusively that drainage causes the soil to become divided into smaller particles, thus enabling it to hold a larger amount of capillary water. The agents which bring about a disin- tegration of the soil particles in underdrained soil are the percolation, or passing of the water down through it, and the action of air and frost. The Growing Season Is Lengthened. Drainage lessens the amount of water that evaporates from the surface and the amount in the soil to be raised in temperature, permitting 62 AGRICULTURAL ENGINEERING the soil to warm up earlier in the spring, and to remain warm later in the fall, thus indirectly increasing the length of the growing season. The cooling effect of the evaporation of water is known to all. The Soil Temperature Is Raised. In a manner similar to that just explained, the soil is maintained at a warmer temperature throughout the growing season, assisting in the rapid growth of plants. Ventilation. Underdrainage causes the soil to be aerated ; for as soon as the hydrostatic water is drawn away by the drains, the space between the soil particles is filled with air. This has a beneficial effect, since all plants require some air. Prevents Surface Wash. When the hydrostatic water of the soil is drawn away by underdrainage, the soil is in a condition to receive a very heavy rainfall before the water will run off over the surface; or, in other words, underdrainage will enable the soil to provide a large reservoir for rain water. Increases the Depth of Soil. As the soil becomes warmer and aerated, the roots strike deeper, thus increasing the depth of the soil available for plant food. Drouth. Strange as it may seem, well-drained soil resists drouth better than wet. The greater fineness and depth of the soil enable it to retain a larger amount of capil- lary water, which is the water chiefly used by plants. The Action of Frost Is Reduced. Soil which is filled with hydrostatic water expands upon freezing and is said to "heave." Although the action of frost may be beneficial, as previously explained, heaving is very injurious to certain crops which are planted in the fall. If the ground water of the soil is drained out, this action is almost entirely over- come. DRAINAGE 63 QUESTIONS 1. Why is water so necessary to plant life and growth? 2. What is meant by "duty of water?" 3. What is the purpose of land drainage? 4. When was tile drainage introduced in the United States, and by whom? 5. How many acres may be reclaimed by drainage in the United States? 6. Explain what is meant by capillary water. Hydrostatic water. 7. Give and explain five conditions of land needing drainage. 8. What is the difference between an open and a retentive soil? 9. How is artificial underdrainage secured? 10. When are open drains advisable? 11. Explain eight primary benefits of drainage. CHAPTER X THE PRELIMINARY SURVEY The Drainage Engineer. The services of a professional drainage engineer are well worth their cost. The success of any drainage system depends upon whether it is well planned or not. If not correctly installed, the whole investment may be worthless. Hence a small percentage of this investment paid in fees to those who by training and experience know how the work should be done is money well spent. It is not the purpose of this text to detract from the work of the engineer, but rather to lead to an appreciation of his work. There is a difference between surveying and engineering. Surveying includes only the taking and recording of such field observations necessary for the designing of a drainage system. The actual work involved in the designing and execution may truly be called engineering. This latter work involves much skill and experience. The Need of a Preliminary Survey. The first step in the drainage of any tract of land is the making of a prelimi- nary survey or an investigation, which should be for the purpose of obtaining a clear idea of the situation and a general knowledge of the nature and amount of drainage which will be required to accomplish the desired purpose. The preliminary survey, then, is the basis upon which the next step, involving the actual work of installing the drain- age system, must depend. There are many things to be con- sidered in the preliminary survey, such as information con- cerning the character and value of the land before and after improving. Careful investigations should be made to DRAINAGE 65 determine if possible the fertility of the land after improving. Then the drainage engineer should go over the tract in order that he become thoroughly familiar with it before under- taking any instrument work at all. If the tract is large and if the ownership is divided, care should be taken that all work from the outset shall conform to the law of the state in which the tract is located. The Extent of the Survey. In the drainage of all but the smallest areas it is quite necessary to make the preliminary survey before attempting in any way to decide upon the final plan. The purpose of the preliminary survey is to obtain the data from which the final plans must be made. The data secured should include the area of the drainage basin, location of the water-shed, direction of the slopes and water courses, and should indicate soil conditions and possible outlets. In securing this data it is necessary that the work be done carefully. Mistakes are costly and can only be avoided by careful work in securing correct information in the prelim- inary survey. Careful work with crude instruments is often more satisfactory than hasty work with expensive equip- ment. Investigation of the Subsoil. An investigation of the character of the soil and subsoil should be made a part of the preliminary survey, for on the data thus secured will depend, to a large extent, the depth of and distance between tile lines. This is quite important in land that is underlaid with sand and gravel or with an impervious stratum of clay. These investigations can best be made with the soil auger. This tool can be made by welding a long handle to an ordinary V/2 or 2-inch carpenter's auger. See Fig. 53. Preliminary Instrument Work. An engineer's level should be used in the preliminary survey to obtain elevations G6 AGRICULTURAL ENGINEERING which will show definitely the lay of the land. It is not safe for even the most experienced to estimate slopes by the naked eye. Map of the Preliminary Survey. A sketch or map should be made indicating the location and elevation of the low and wet areas in the land, and also the watershed. In some cases where the land is quite flat it is desirable to take levels at regular intervals over the entire tract, and, perhaps, to prepare a contour map as explained in a previous chapter. With this information it is possible to lay out the drainage system, if conditions show that a practical system is possible. It is desired to lay special emphasis upon the importance of this preliminary survey. The quite common practice of laying tile largely by guess, without a consideration of the land area to be drained or the capacity of the tile, cannot be too severely criticised. The large amount of insufficient and unsatisfactory drainage to be found everywhere is silent testimony to the statement that tile drainage must be done carefully and intelligently. QUESTIONS 1 . What is the purpose of a preliminary survey? 2. Why should a drainage engineer be employed on important work? 3. What is the difference between surveying and drainage engineer- ing? 4. What should be included in the preliminary survey? 5. Why should the subsoil be investigated? 6. To what extent should an instrument be used in a preliminary survey? 7. What should be included in the map of the preliminary survey? CHAPTER XI LAYING OUT THE DRAINAGE SYSTEM Definitions of Terms. Before beginning a discussion of drainage systems it is well that the meaning of some of the common terms used in connection therewith be explained. The discharge end of the tile line or main is called the outlet, and the upper or upstream end is called the head. The term lateral is used for the single tile line with no branches. The main is the line of large tile that carries the discharge from a number of laterals. If the discharges from several laterals are received into a larger tile line before it reaches the main, the line which receives the discharge from the laterals is spoken of as the submain. It is customary to designate the laterals and submains by number and the mains by letter. Direction of Drains. All drains should be placed paral- lel to the slope of the surface. The surface of the ground water, or the water which flows into tile drains, is usually parallel to the surface of the ground, and the water is con- stantly flowing down the slope. If a tile line be laid across the direction of the slope, it will not receive any water from the lower part of the slope; and, in fact, a part of the water from above may flow past the tile line. Depth of Tile Drains. Except in very retentive soil through which the water does not percolate rapidly, the tile should be placed at a good depth. It takes little time for the water to pass straight down to a tile, but it takes more time for it to flow horizontally through the soil. By 68 AGRICULTURAL ENGINEERING placing a tile deep, a large reservoir is provided for rainfall, and the tile will have a longer time to carry the surplus away. Distances between Drains. It is a practice in some- localities where an average soil exists, to consider that tile will drain the water from the soil to a distance of one rod for each foot in depth. As the ground water flows away through the tile lines after heavy rains, the level of the ground water is first lowered directly over and near the tile, which causes side flow of the water through the soil. If t"he soil is open or sandy, this flow through the soil is rapid, and the level of the _&- ^ — x — oi co -* lo t^ x © — co tj- o n oo n m © © .-I © © <-> Ol Ol Ol CO l^N- © l>- CO X co-* ^ © CO © - X © © O O i co co © co ©co coco © co LO LO t^ t^- CO ^ ^H v ..'."• ;"-'■''' Fig. 55. A large tile ditching machine at work. to furnish the power. Traction gearing drives the whole machine forward at the proper speed, which, in favorable soil, may be as much as 175 feet per hour when digging four feet deep or less. The great difficulty in the past has .been to design a machine which would dig a ditch to grade in soft soil having but little supporting power. This has been overcome to a great extent by providing caterpillar traction wheels or DRAINAGE 89 treads which provide a large area of supporting surface. These machines can be used to the best advantage on long lines of tile and where the soil is reasonably dry and free from boulders. In no case should a machine be used which does not permit of an inspection of the grade and of the tile as it is laid. The Guess System of Laying Tile. At the present time there is very little tile placed in the ground on grade lines made simply by guess. The majority of such systems are failures, and mistakes have been so evident where this method was practiced that it is uncommon now to see a system installed without a survey. The Water-Level Method. - But little better than the guess method of installing drainage systems, is the water- level method, which is used to some extent today and is responsible for a large number of failures. This method of laying tile is used where there is some water in the ditch. Where the fall is slight, water can not be depended upon to give a proper grade. The ditch is sure to be dug below the grade at certain places, giving a back fall. After the ditch has been dug too deep, there is little chance of correcting the mistake by filling in. The water-level method is so inaccu- rate that, even where the fall is great and there is little danger of creating back fall, the grade line will be so irregular that the efficiency of the tile will be much reduced. Method of Grad- ing- Ditches. Two general methods of The line method of grading tile ditches. 90 AGRICULTURAL ENGINEERING grading ditches are in vogue. One is to stretch a cord or line above the surface parallel to the grade line, using a measuring stick to locate the grade. This is generally known as the "line and gauge method." The other, the "target method," consists in locating a line of sights or targets above the ditch, parallel to the required bottom, and the depths at all points are gauged by sighting over these sights and using a measuring stick to determine the proper depth. When the line is used it must first be decided how far above the bottom of the ditch to place it, and a measuring rod of this length provided. Five or seven feet are convenient distances for the usual depth of dig- ging. The line may be stretched directly over the ditch or to one side. The first instance requires that a yoke be constructed over the ditch, while the latter requires only a single standard or stake. Some tilers object to the line stretched over the ditch, as it is more or less in the way, but there is no doubt that more accurate measurements can be made when the line is so placed. If the line be stretched at one side of the ditch, a measuring stick 'with a bracket must be used. To obtain The target method of tile ditches. grading DRAINAGE 91 greater accuracy, a level-tube is sometimes placed on the horizontal arm of the bracket. The height of the line above the grade stake at each station is obtained by subtracting the cut from the distance the line is placed above the grade line. Thus, if 7 feet be selected as the length of the measur- ing stick, and the cut at a certain station be 3 feet 5 inches, then the line should be placed 7 feet less 3 feet 5 inches, or 3 feet 7 inches above it. If this operation be performed at all stations, it will be seen that the line will be parallel to the bottom of the ditch and 7 feet above it. A fishline or a fine wire makes an excellent line to use for this purpose, as it may be stretched very tight, overcoming the sag to a large extent. Some experienced tilers prefer the "target method," as it is more convenient. It is, however, more pro- ductive of errors. Selecting Tile. Great care must be used in selecting drain tile. Farm drainage is too expensive for one to take serious risks with tile of questionable durability. At the present time there is much discussion in regard to the rela- tive merits of clay and cement tile. Attention has been called repeatedly to instances where both kinds have failed. Clay tile has the advantage in that it has been in use a much longer time than cement tile, and a good clay tile is as per- manent as any material that can be secured. Careful speci- fications for tile and methods for testing the same have not as yet been prepared or devised. Clay tile should be well burned and of uniform shape and color. They should be straight, with square ends, and when two are held in the hands and struck together they should give a good sharp ring. Large lumps of chalk or lime in the clay must be guarded against. Inferior tile are those of light color, porous and laminated. These are quite sure to become disintegrated when placed in the soil. 92 AGRICULTURAL ENGINEERING Cement tile are very satisfactory when properly made and are of recognized quality. No attempt should be made to make the tile porous, but as dense a mixture of cement as it is possible to secure should be used. Where good coarse sand is used, a mixture of 1 part cement to 23^ parts of sand has been used by the best manufacturers. A mixture con- taining less cement will no doubt make good tile. Large cement tile should be reinforced with steel. Fig. 5S. Drain tik Those at the left are of cement and those at the right are clay. In installing a drainage system, a careful inspection of the tile should be made. All inferior tile which are soft, porous, cracked, or overburned until of reduced size, should be discarded. Laying Tile. Great care should be taken in laying the tile. Small tile should be laid with the tile hook (See Fig. 59), but there is little doubt that the tile is laid more accu- rately when laid by hand. Each length should be turned as it is laid to secure the best fit. When a tile hook is used on tile which are slightly curved, the bend of the tile is quite sure to be up, leaving a larger crack at the top of the tile rather DRAINAGE 93 than at the bottom, which is undesirable. Tile should be fitted together so. that there are no cracks over 3^ inch wide. Small holes at the joints may be cov- ered by broken pieces of tile. In digging the ditch and laying the tile, the work should always begin at the outlet. The tile should be laid as fast as the ditch is dug, to pre- vent the destruction of the ditch by rain. This would happen if the water should be allowed to flow down the unprotected ditch. In most soils, the open ditches are quite apt tO Cave in if left Open F ig. 5 9. Laying- tile with the tile hook. during rain storms. Laterals should be joined to a main by "Y" connections furnished by the tile manufacturers. The cheapness of these connections does not justify the work of cutting tile to form a connection. Laterals should enter the main at as sharp an angle as convenient. When the connection is made at right angles, the flow of the water from the laterals has a tendency to check the flow of the water in the mains. Fig-. 60. Sketches showing proper method of joining lateral drains to mains. From Ohio Exten. Bui. 47. 94 AGRICULTURAL ENGINEERING In laying through quicksand, time should be given for the water to drain out and allow the sand to become as firm as possible. This is rather a slow process at times, but it is the only method to follow in watery quicksand. To prevent the sand from flowing into the open end of the tile, a screen of hay or grass may be used. If there are bad pockets, it may be necessary to lay the tile upon boards to keep them to grade. Inspection. Before the tile are covered the work should be thoroughly inspected to see that the tile are laid to grade, and that the openings between the tile are not too large. In inspecting the grade, the level may be set over the line of tile and the line of sight set to the same slope as the grade line. The reading of the rod held upon the top of the tile should be the same at all points, so long as the slope of the grade line does not change. After inspection, the tile should be "blinded in" by cutting enough dirt from the side of the ditch to cover it to the depth of two or three inches. This earth from the side of the ditch is more porous than that from the surface, and permits the water to enter the tile more readily. The shoveling and spading of the soil have a ten- dency to puddle it and make it water-tight. After blinding, the ditch may be filled. QUESTIONS 1. What is the work of the tiler? 2. Explain in a general way the digging of tile ditches by hand. 3. Name and describe the tools used in tile ditching. 4. Where may tile ditching machines be used to advantage? 5. How much ditch may be dug with a machine in an hour under favorable conditions? 6. Why should not tile be laid by guess? 7. Explain the "water level" method of installing drains. 8. Describe the line method of digging ditches to grade. DRAINAGE 95 9. What relation does the line of targets or sights in the target method of digging ditches to grade, bear to the grade line? 10. What points should be observed in selecting drain tile? 11. Explain in detail how the targets are located. The line. 12. Describe the use of the tile hook. 13. How should tile' be fitted? 14. How may tile be laid through quicksand? 15. What is meant by "blinding" the tile? 16. Why should tile lines be inspected? 17. Describe the work of inspection of tile drains. CHAPTER XV CONSTRUCTION OF TILE DRAINS Filling by Hand. After the tile are laid and blinded in, as little hand labor as possible should be used in filling the ditches. The usual price for the work of filling ditches by hand is ten cents per rod, while the same work will cost one to two cents per rod where horses and implements are used. Of course there are places near and under fences or embank- ments where the ditches must be filled by hand. ling' the ditch with a plow. Filling with the Plow. One of the most convenient and satisfactory methods of filling a tile ditch is to plow it full. To do this successfully, an ordinary stirring plow may be used, one horse being hitched to each end cf a long double- DRAINAGE 97 tree which will permit one horse to walk on each side of the ditch. The soil and waste banks are plowed toward and into the ditch until it is entirely filled. It is best that one man drive the team while another hold the plow. Three horses may be used upon a twelve-foot evener, two horses hitched to one end and one to the other. In this case the plow is attached four feet from the end to which the team is hitched. The plow is not well adapted for filling ditches dug in meadow land. Filling with a V Drag. A V drag is a useful and quick means of filling ditches. The wings of the drag should be vide enough in front to reach from the outside of one bank of excavated earth to the outside of the other, and should be brought to within a few feet of each other at the rear. Filling with Road Machines. A scraping road grader may also be used to fill tile ditches. The blade may be set at such an angle that the waste bank is scraped over into the ditch. Like the road drag, the road machine will do good work if the ground is not too wet. Another common method is to fill the ditch with a .slip Fig. 02. Filling the ditch with a mad grader. AGRICULTURAL ENGINEERING scraper or other form of handled scraper. A team is hitched to the scraper by a chain so as to pull directly across the ditch. The scraper is placed behind the waste bank, and the team stepping ahead pulls a scraper load of earth into the ditch. The team is then backed and the scraper pulled back by hand. The latter operation furnishes the greatest objec- tion to this system, for it is very heavy work. Outlet Protection. All tile outlets should be protected in such a manner that the earth will not be washed away from the end tile and cause them to be displaced. The cheapest form of outlet is made by preparing a wooden box into which the last few lengths of tile may be placed. This is not a very satisfactory form of protection. The bet- ter plan is to build a Fig. 63. a S ood outlet protection for a tile bulkhead of masonry drain. It is desirable, however, that grating or bars be placed across the outlet to keep out and ail apron UPOn small animals. which the water may spill without washing away the soil. The latter may not be needed, or a few stones will generally suffice. Concrete makes a splendid bulkhead. A six- to ten-inch wall where only two or four feet of earth is to be held back will be found sufficient. This wall should extend well below the tile to prevent undermining. The last few tile should be glazed sewer tile, as they will resist freezing and thawing better than common drain tile. Iron rods or netting DRAINAGE 99 should be placed across the outlet to prevent the entrance of small animals which might, by dying in the tile, become an obstruction. Catch Basins, or Surface Inlets. Where there is sure to be considerable surface flow, it is best that this be taken into the tile as soon as possible. The catch basin is simply a grated inlet leading directly to the tile. The basin is usually built deeper than the tile to allow dirt, which might be washed in, to settle and not be carried into the tile with the water. This sediment should be cleaned out from time to time. A concrete box, 3^ feet across and with 4-inch walls, makes a very satisfactory catch basin. The box should extend 2 feet below the line of tile and should have a removable cover. Large sewer pipes with side connections can be used conveniently for this purpose. Silt Basins. Silt basins have been recommended for tile lines where the grade is reduced, and are designed to provide a receptacle to catch the silt that is apt to settle at that point. They are constructed with remov- able covers through which the sediment may be removed from time to time. There is little doubt that these devices are very harmful in checking the flow of water in the tile, and it has been the experience of the author that these basins are never given attention when they require it. 64. A silt basin. 100 AGRICULTURAL ENGINEERING Trouble with Roots of Trees. Tile drains laid near aquatic, or water-loving, trees, are sometimes partially, if not entirely, obstructed by roots of these trees. The willow and water elm are among those that give the most trouble in this respect. Fruit trees give very little trouble, and drains may be laid in orchards with impunity. If a drain must pass within 30 or 40 feet of any of the trees that are aquatic by nature, the trees should be cut down drain which became comp] from a willow tri e. tclv obstructed by roots and killed, or sewer pipes with cemented joints should be used near the trees, which will prevent the roots from getting into the drains. Drainage Wells, or Sinks. Wells are occasionally used as outlets for tile drains. It is known that about as much water may be discharged into a well as may be pumped from it. An investigation of the success of wells as drainage out- DRAINAGE 101 lets in Iowa reveals that in certain localities wells are emi- nently successful; in others, they are failures after a very short time. The successful wells seem to be those that penetrate crevices in the rock stratum below the surface. These wells seem less apt to become clogged with the fine silt carried into the well by drainage waters. It is under- stood that these wells are to be used for no other purpose than as drainage outlets. Cost of Drain Tile. To those unfamiliar with tile drain- age, it is thought that the following schedule of tile prices at the factory will be useful. It is to be remembered that prices must necessarily vary with factories, and freight in many cases is a considerable item. Cost of drain tile at the factory. Size of tile in inches Weight. Lbs. Cost per 1000 4 5 7 9 11 17 26 35 $ 16 20 G 28 8 45 10 80 12 100 Schedule of Prices for Digging Ditches. The follow- ing schedule prices have been in quite general use through- out Iowa during the year 1911. Cost of digging tile ditches. Size of tile in inches Price per rd. 3 ft. deep or less Extra per rd. for each inch of depth over 3 ft. Extra per rd. for each inch of depth over 6 ft. 4, 5, and 6 7 and 8 $.44 .50 •62^2 .75 $.01 M .01 L> .02 .03 $.03 .03^ 9 and 10 .04 12 .05 102 AGRICULTURAL ENGINEERING QUESTIONS 1. Why is it advisable to use little hand labor in filling the ditches? 2. How may the plow be used in filling ditches? 3. Describe the use of the V drag and road grader in filling ditches. 4. Why should the outlet of a tile drain be protected? 5. Describe the construction of an outlet protection. 6. What is the purpose of a catch basin? 7. Describe the construction of a catch basin. 8. Where is a silt basin used and what is its purpose? 9. How may tile drains be protected from the roots of trees? 10. To what extent may a well be used as an outlet for tile drains? 11. Compare the prices of drain ti'e furnished in the text with those of 3 r our town or city. 12. What are the usual prices charged for tile ditching? CHAPTER XVI OPEN DITCHES Drainage of Large Areas. Where large areas are to be drained, it may not be practical to install tile of sufficient size to care for the drainage water or run-off. Thus in the large drainage systems it is to be expected that open ditches, as distinguished from covered or tile lines, will be used to supplement the tile. . Construction of Open Ditches. In the construction of open ditches, not only the size must be con- sidered, but also the form of the ditch. The size of the ditch will depend upon the capacity of ditches dug to various grades and upon the area and character of the catchment basin. The capacity of open ditch- es will be discussed later. Care should be used in construct- ing the banks of the ditch so that the ditch will remain open and not become filled by the caving of the banks. In certain soils a slope of 1 foot horizontal to 1 foot ver- tical for the sides of the ditch may be maintained; and in other cases, as in the case of loam soil, the slope must be 1% to 1, or even less. In digging a ditch it is often not possible to secure the desired slope in the beginning, but the ditch A floating dredg ditches. for digging open 104 AGRICULTURAL ENGINEERING is made deep enough so that as it caves in it will still be of sufficient size. The heap of excavated earth from a ditch is called the waste bank. The space between the waste bank and the edge of the ditch is called the berm. Waste banks present an ugly appearance and are an objectionable feature of open ditches, unless the earth is used to fill in low places. Cost of Open Ditches. Small open ditches are made with the plow or scraper. These are usually undesirable, as they do not furnish a good outlet for the ground water. Large open ditches are generally built by contractors who are provided with ditching or dredging machines. In many cases these are floating dredges which begin at the head of the ditch and dig toward the outlet. There are other types of ditching machines, which operate on tracks laid on each side of the proposed ditch. These large machines remove the earth from the ditch at a very reasonable cost, varying from 5 to 15 cents per cubic yard. Disadvantages of Open Ditches. There are many dis- advantages of open ditches. Small ditches do not furnish good outlets for the ground water because they cannot be kept open to sufficient depth. It is to be noted that an open ditch will not drain below the surface of the water in the ditch. Again, open ditches interfere seriously with the culti- vation of the land, and are very unsightly. They occupy so much land as to make their upkeep expensive. Further- more, more plant food is carried off by an open ditch than by a tile drain. If the water must pass down through the soil to a tile drain, more or less of the plant food will be left in the soil. Capacity of the Open Ditch. As in the case of tile drains, there have been many attempts to prepare a formula which would enable one to compute the capacity of open ditches. There are a good many factors which influence the flow of DRAINAGE 105 water in ditches. One of the most important of these is the cleanness of the ditch. A very little rubbish, if allowed to accumulate in an open ditch, will decrease its capacity materi- ally. Grass and weeds may grow in an open ditch to such an extent as to reduce the capacity of the ditch to less than half. Pig. 07. An excavator for digging' open ditches, which is carried on tracks laid at each side of the ditch. The following tables computed by Kutter's formula will be useful in this connection.* These tables are taken from *Kutter's formula for the velocity of flow in open ditches is as follows" 1.811 + 41.6.5 + .00281 V = 1 + Ml. 65 + .00281 X 1/ V in which v = velocity of flow in feet per second. i = sine of the inclination of the slope, or the fall of the water surface in a given distance divided by that distance. _ r = area of the cross section in square feet divided by the wet perimeter in lineal feet. n = coefficient of friction for different sizes of canals and with different degrees of roughness. 106 AGRICULTURAL ENGINEERING Bulletin 78 of the Iowa experiment station. A coefficient of roughness of .03 has been used and they are for ditches having the sides with slopes of one foot horizontal to one foot vertical . The ditches are not to run more than 8-10 full, where the capacity is mentioned. Above the upper heavy lines in the table the % inch standard of water for 24 hours is used; between heavy lines the Yi m ch standard; and below the lower heavv lines the M inch standard. Number of acres drained by open ditches. Depth of water 5 feet. Depth of ditch at least 6J^ feet. Grades Average width of water Per cent Ft. per mile 6 feet s feet 10 feet is feet 20 feet 30 feet 50 feet 0.02 1.0 980 1470 1900 5000 7150 23800 43800 0.04 2.1 1390 2090 2800 7200 20400 33500 62500 0.06 0.08 3.2 4.2 1710 1980 2560 2980 5100 6100 17600 20400 24700 30000 40800 48800 75500 88000 0.10 5.3 2220 5010 7600 23400 83400 54500 98000 0.15 7.8 2720 6300 17100 28700 40500 66700 120000 0.20 10.6 4820 7300 19500 33000 47000 77000 139000 0.25 0.30 0.40 13.2 15.8 21.1 5370 5900 6830 16300 17900 20600 21900 23900 27700 37500 40700 47000 53000 57000 67000 86000 94000 155000 170000 0.50 26.4 7600 23000 31000 0.60 0.70 0.80 0.90 31.7 37.0 42.2 47^5 16700 18100 19000 20500 25200 27300 33900 DRAINAGE 107 Number of acres drained by open ditches. Depth of water 7 feet. Depth of ditch at least 9 feet. Grade Average width of w ater Per Feet s 10 15 so SO 50 cent per mile feet feet feet feet feet feet 0.02 1.0 2300 4700 16600 28000 48000 88500 0.04 2.1 4850 6740 23400 35400 58000 106000 0.06 3.2 5920 17000 29600 43400 72000 129000 0.08 4.2 6940 19100 34200 50000 83000 150000 0.10 5.3 7720 21800 38400 56000 92600 167000 0.15 7.8 19400 27000 47200 68500 112000 202000 0.20 10.6 22400 31300 54200 78700 130000 235000 0.25 13.2 25000 34800 60500 88000 146000 0.30 15.8 27400 38200 66200 96500 0.40 21.1 31700 44100 0.50 26.4 35400 QUESTIONS 1. When may it be necessary to use open ditches as drains? 2. What are some of the disadvantages of open ditches or drains? 3. What slope is usually given the sides of open ditches? 4. What is the "waste bank"? The "berm"? 5. How much does the digging of open ditches cost per cubic yard? 6. What factors influence the capacity of open ditches? 7. What formula is generally used in computing the capacity of open ditches? CHAPTER XVII DRAINAGE DISTRICTS Definitions. The drainage district is an organization of the owners of land for the purpose of constructing and main- taining a "drainage system where the cost is to be shared in proportion to the benefits derived. Such an organization is necessary where an individual cannot drain without involving the use of the land of his neighbors. A drainage district may include at least three classes of land : First, all of the adjacent land which in itself may not be in immediate need of drainage; second, land in partial need of drainage; and third, worthless land which would be reclaimed by drainage. In every drainage district there are two kinds of work: First the co-operative work, such as the construction of large drains or ditches; second, the individual work required by land owners in supplying laterals or submains. Drainage Laws. The organization of drainage districts is a matter which involves many details and which is subject to special laws in most states. These special drainage laws usually cover the essential steps of procedure; and the features of the organization of a drainage district are as follows: First, the right of the property owners to petition for the construction of drains alleged to be of public benefit. Second, provision for making and collecting assessments, as well as the appraisement and payment of damages. Third, the establishment of the perpetual right of land owners to the use of the drains wnich are to be constructed in the district. Fourth, the authority to obtain money by incur- ring debt or selling bonds, under the proper legal regulations. DRAINAGE 109 Survey and Report. After a petition has been made for the formation of a drainage district, the law places the matter of a survey and report of the district in the hands of a board or an officer of the law to order the survey and report by an engineer. This report should be comprehensive in extent, and should furnish sufficient data concerning the district to enable the board or the officer of the law to determine whether or not it will be of benefit to the district as a whole. The report in this case should include an estimate of the cost of the work to be performed in the district, covering the actual cost of the construction of the drains and the neces- sary work in connection therewith, such as construction of bridges, etc. It should include an estimate of damages to all property owners which may be incurred from the con- struction of the drains; also estimates of the cost of the engineering, of fees of the commissioners, and of all legal expenses arising from the suits which may be carried to court. Damages. Provision is usually made for a commission of disinterested men to appraise the damages which may come to the individual property owners through the construction of the drainage work. Sometimes this board of commis- sioners is also called upon to levy the assessment of benefits. Assessment of Benefits. It is usually provided by law that the total cost of the drainage district shall be assessed according to the benefits derived. These benefits may be either specific or general; specific in that the value of the land may be increased, and general in that the health of the com- munity is improved by the drainage district. There are many things involved in levying an assessment, and these are more or less subject to state laws. Copies of drainage laws may be obtained by applying to the secretary of state in any state, and these laws may be made the subject of an interesting study- 110 AGRICULTURAL ENGINEERING QUESTIONS 1. What is a drainage district? 2. When is a drainage district necessary? 3. What three classes of land may it include? 4. What two kinds of drainage work does it include? 5. What are the four essential features of laws relating to drainage districts? G. What is required in the survey and report of a drainage district? 7. What docs the cost of a drainage district include? 8. Describe the assessment of damages in a drainage district. 9. What is meant by assessment of benefits? REFERENCE TEXTS Engineering for Land Drainage, by C. G. Elliott. Practical Farm Drainage, by C. G. Elliott. Land Drainage, by Manley Miles. Irrigation and Drainage, by F. H. King. Notes on Drainage, by E. R. Jones. Bulletins of U. S. Department of Agriculture. Bulletins of state experiment stations. PART THREE— IRRIGATION CHAPTER XVIII HISTORY, EXTENT, AND PURPOSE OF IRRIGATION Control of Soil Moisture. Attention has been called to the importance of having the soil contain the proper amount of moisture to furnish the best conditions for the growth of crops. Plants require that the soil contain a sufficient amount of moisture, not only to dissolve the plant food, but also to enable them to absorb and assimilate it. Much of the plant food in the soil is made available through the action of micro- scopic organisms. The vitality of these organisms depends largely upon an adequate supply of moisture. As has been explained, drainage is for the purpose of relieving the soil of a surplus moisture; on the other hand there may be in certain localities at times and in other localities at all times a defi- ciency of moisture from natural sources. Irrigation is simply a process of supplying water to the soil by artificial means, either to make it possible to grow crops or to increase pro- duction. Irrigation, then, is the reverse of drainage; and although this be true, it is to be noted that irrigation practice has many features in common with drainage. The management of water is much the same, regardless of whether it is to be removed from the soil as in the case of drainage, or supplied to the soil as in the case of irrigation. The importance of irrigation may be made clear by calling attention to the fact that many crops, like potatoes and corn, 112 AGRICULTURAL ENGINEERING during the part of the growing season when the tubers or ears are forming, require a large amount of plant food and moisture. At this time the plants have a wonderful root development, absorbing a great amount of soil moisture; and if maximum yields are to be secured, sufficient moisture must be supplied. History of Irrigation. The practice of irrigation runs back even before the time history began to be written. There is evidence that irrigation was practiced along the Nile and the Euphrates rivers more than 2000 years b. c. There were also large irrigation works in Baluchistan and India before the Christian era. Many of these ancient works have been abandoned, yet not a few have been maintained and are still in use. In the Western Hemisphere, irrigation was practiced at a very early date in Peru, in South America, and by the Aztec civilization in North America. The remains of ancient irrigation works are to be found in parts of Arizona and New Mexico. Settlers in the vicinity of San Antonio, Texas, began to practice irrigation as early as 1715. When the Mormons settled in the Salt Lake Valley in 1847, they soon began to give attention to the matter of irrigation, and much credit for the development of irrigation methods should be given to these pioneers. As early as 1870, a colony known as the Greely Union Colony was established in northern Colorado, and began the construction of works for irrigation. Since that time irrigation has grown by bounds in the United States. Dr. Elwood Meade, former Chief of Irrigation Investiga- tions, U. S. Department of Agriculture, has estimated that the area now under irrigation in countries from which it is possible to secure reliable statistics, aggregates 85,000,000 acres. Taking into account countries which do not have IRRIGATION 113 statistics, he estimates that the total irrigated area is not far from 100,000,000 acres, or about the area of the state of California. This area is being rapidly increased. Professor F. H. King states in his book, "Irrigation and Drainage," published in 1907, that the area irrigated in India was about 25,000,000 acres, in Egypt about 6,000,000 acres, in Italy 3,700,000 acres, in Spain 500,000 acres, and in France 400,000 acres. The following data are taken from the preliminary report of the United States Census of 1910. These figures are for the arid states of the United States, and do not include rice irrigation. Total acreage irrigated in 1909 13,739,499 acres Area irrigation enterprises were capable of irrigating in 1910 19,355,711 " Area included in irrigation projects 31,112,110 " Total cost of irrigation systems constructed $304,699,450 Average cost per acre (based upon construction to July 1, 1910, and acreage enterprises were capable of supply- ing in 1910) $15.76 Average annual cost per acre of maintenance and opera- tion $1.07 PURPOSES OF IRRIGATION To Supply Moisture. By far the most important pur- pose of irrigation is to supply moisture when needed for plant growth, as has already been explained. In some localities crops cannot be grown at all without irrigation, and in others irrigation is practiced in order to supplement rainfall and increase the crop. To Control Temperature. In some localities irrigation is practiced chiefly to control the temperature. Cranberry marshes are often flooded with water to protect the crop from frost. In other localities the soil is warmed in winter by 114 AGRICULTURAL ENGINEERING causing a thin sheet of water to flow over it, and the same process may have a cooling effect in summer. This kind of irrigation is practiced in Italy where a supply of warm water is obtainable. To Kill Weeds. In rice fields the surface of the ground is flooded in some instances largely for the purpose of killing weeds, thus reducing the labor of cultivation. Such a system also protects the crop from the ravages of birds and insects. To Supply Fertility. Irrigation may be practiced in some localities in order to supply additional fertility to the soil. Some irrigation water carries a large amount of sediment which is very rich in plant food. The water may also con- tain soluble plant food, as phosphoric acid, potash, and nitrogen. The fertility of the land along the Nile, in Egypt, which has been irrigated for ages, is maintained largely by the addition of fertility through the irrigation waters. It is true that some water supplies cannot be used for irrigation because they contain poisons injurious to plants. This is often true of the water of rivers into which the refuse from smelters and certain kinds of factories is discharged. Disposal of Sewage. In many instances the disposal of sewage waters from cities has not only been facilitated, but also made a matter of profit, through irrigation. Sewage water, when applied to the soil is quickly purified and made harmless. Sewage water is usually very rich in plant food. QUESTIONS 1. Define irrigation. 2. Why is an adequate supply of moisture in the soil important? 3. How long has irrigation been practiced? 4. How much land in the world is now irrigated? In U. S.? 5. What is the main purpose of irrigation? 6. Name and describe four other purposes of irrigation. CHAPTER XIX IRRIGATION CULTURE The Amount of Water Required for Crops. As explained in the part of the text devoted to drainage, nature does not in all cases supply the amount of water which will produce the maximum growth of plants. In this connection the question of the amount of water which, when properly applied, will produce a paying yield of crops, is one of vast importance to those interested in irrigation. In most instances irriga- tion water is expensive, and for the sake of economy no more water should be used than necessary. The question, how- ever, is very complex, and cannot be treated otherwise than very briefly in this text. The water which comes to the soil leaves it in three dif- ferent ways: First, a portion of it is transpired through plants; second, a portion evaporates from the surface of the soil ; third, a certain amount of the water flows away over the surface or as underground drainage. Plants grow by using water, as described under the first head. The other two ways in which the water leaves the soil may be considered losses, and should be reduced to the minimum. There are many conditions which modify the amount of water required for irrigation. These may be enumerated as follows. The Nature of the Crop Grown. Some crops transpire more than others, because they have more foliage to give off the moisture. The root growth of the plant is a factor in determining the amount of moisture used, as the roots of some 116 AGRICULTURAL ENGINEERING plants strike deep and are thus able to draw moisture from a larger volume of the soil. Character of the Soil. The amount of water required is dependent largely upon the character of the soil; thus the soil may be so open or porous as to permit a rather large loss of moisture by seepage. The character of the soil influences to a rather large extent the effectiveness of the soil mulch which conserves the moisture in the soil, which is to be described later. Character of the Subsoil. The character of the subsoil is a factor in determining the amount of water required by the plant, for an open subsoil will be the means of a great loss of moisture by percolation downward. Effect of Cultivation. Cultivation for maintaining a soil mulch will influence to a large extent the amount of moisture required for most satisfactory plant growth. In dry-farming localities, as well as elsewhere, moisture is conserved by keep- ing a dust mulch or fine layer of soil over the surface. Much of the moisture in the soil available for the growth of plants may be retained in this way from one wet season through a dry season. After a rain or an application of irrigating water, it is customary to cultivate the soil as soon as practical in order to form this mulch. Closeness of Planting. A dense, heavy crop that shades the ground will check the loss of moisture by evaporation, thus it is customary to irrigate grain crops most thoroughly at the time when they are heavy enough to shade the ground. Character of Rainfall. The character of the rainfall is an important factor in fixing the duty of water; one heavy rain which penetrates the soil to a considerable depth is more use- ful than several light rains which are quickly evaporated. Thus localities which have a wet season are often able to IRRIGATION 117 grow crops, even though the actual rainfall is quite small, inasmuch as it may be stored in the soil and conserved by cultivation for use during the dry season. Frequency of Applying Water. In like manner the fre- quency of applying irrigation water is a factor which deter- mines the duty of water. One good thorough irrigation, under most conditions, is preferable to several light appli- cations. The Amount of Water Used in Irrigation. It is to be expected that the student is anxious to know how much water must be applied to the soil to supply the plants where the rainfall is not sufficient, or where the rainfall is too slight to be considered. The amount of water is usually designated in inches or feet. This means that the water applied is sufficient to cover the entire surface to a depth indicated in inches or feet as occasion may require. The actual amount of water varies largely, as may be expected. Mr. H. M.Wilson, in "Manual of Irrigation Engineering," gives the following table setting forth the amount of water used in irrigation in different countries. Amounts of water used in irrigation in various countries. Name of country No. of acres per second foot * Xo. of inches per 10 days Northern India Italy Colorado Utah 60 to 150 65 to 70 80 to 120 60 to 120 80 to 100 70 to 90' 60 to 80 60 to 80 100 to 150 100 to 150 150 to 300 3.967 to 1.5S7 3.661 to 3.4 2.975 to 1.983 3.967 to 1.983 Montana 2.975 to 2.38 Wyoming Idaho New Mexico 3.4 to 2.644 3.967 to 2.975 3.967 to 2.975 Southern Arizona 2.38 to 1.587 San Joaquin Valley". Southern California . . 2.38 to 1.587 1.587 to .793 *See Chapter XXI for definition of this unit. 118 AGRICULTURAL ENGINEERING Dr. Elwood Meade furnishes the following table as the duty of water for different crops in the United States : Depth of -water used for different crops and the irrigation season for each. Crop Depth of Irrigation. Feet Irrigating season Potatoes Alfalfa Orchard Wheat 3.94 3.39 2.76 2.68 2.15 1.73 1.49 1.40 May 17, to Sept. 15 April 1, to Sept. 22 April 15, to Sept. 2 April 1, to July 26 Sugar beets Oats Barley Corn July 13, to Aug. 17 May 22, to Aug. 20 June 12, to Aug. 1 July 24, to July 29 Crops Grown by Irrigation. Most farm crops can be grown successfully by irrigation methods, and no attempt will be made here to discuss all. It is desirable, however, to discuss some of the chief crops grown in this way. Grain. One of the principal crops grown by irrigation is grain, and it is one which adapts itself well to irrigation methods. When land is brought under irrigation, grain is usually one of the first crops to be grown. There are several reasons for this. They are food crops and are always in demand. They do especially well on virgin soil and they require the least output in preparing the land. Furthermore, grain is an excellent crop to prepare the land for other crops to follow later. In most localities there is enough moisture in the soil to start the grain at the beginning of the growing season, and the number of times that irrigation water must be applied will depend upon the factors which have been described. In some localities along the Pacific coast and in New Mexico and Arizona it may be necessary to apply irrigation water during the winter or nongrowing season. In other localities IRRIGATION 119 where there is sufficient rainfall to start the grain, irrigation is not practiced until the grain is six or eight inches high. It is generally considered better, however, if it is found neces- sary to irrigate near the time of planting, to irrigate before planting rather than after. On light soils with free underdrainage it may not be possible to retain the moisture through the winter season, in which case irrigation should be practiced near the time of planting. It is to be noted, however, that in some localities it may be advisable to irrigate after planting, in order that the time of planting may not be delayed. The principal danger in irrigation after planting lies in the formation of crusts. When the crust forms it must be either softened with a subsequent irrigation or broken up mechanically by means of special rollers or peg-tooth harrows. It is considered best not to furnish so much water as to grow a large straw crop. Heavy straw crops make a large demand upon the soil moisture, and are not essential for large crops of grain. Grain is also apt to be of more value when grown on straw that does not have a rank growth. It is customary, then, to dispense with as much irrigation during the growing season as is possible without lowering the vitality of the grain. In some localities only one irrigation is necessary, and this is given at the time when grain is in the milk stage. It seems quite important that the grain be supplied with abundant moisture at this time. In other localities where it is quite dry and where the conditions of soil and climate require it, two or more irrigations may be given. Alfalfa. One of the great crops of the irrigated land in the United States is alfalfa. Like grain, if an ample supply of moisture is supplied to the soil before the seed is sown, there will be little need of another early irrigation. If the 120 AGRICULTURAL ENGINEERING land be irrigated following the sowing of the seed, the same difficulties will be encountered as in the case of grain. The first thorough irrigation is usually given after the crop shades the ground. After the first crop is harvested, each subsequent crop is irrigated, as a rule, but once. Prac- tice as regards the time of this irrigation varies in different localities. Sometimes the water is applied perhaps a week or ten days before the time of cutting. The intervening time is necessary in order that the soil may be dried out suffi- ciently to enable the mowing machine and hay tools to operate successfully. In other localities it is practical to cut the crop first and apply the water afterwards. Potatoes. Favorable conditions for the growth of potatoes are to be found generally throughout the irrigated regions in the United States. In the irrigation of potatoes, care should be used not to irrigate oftener than is necessary, as a low temperature is produced which is unfavorable to the growth of potatoes. For this reason the minimum of water is supplied, until the time for the formation of the tubers. Potatoes seem to thrive best when the irrigations are few but thorough, and cultivation is practiced to retain the moisture between irrigations. Sugar Beets. About two-thirds of the beet sugar produced in the United States comes from the irrigated sections, and it is one of the crops which can be very success- fully grown by irrigation methods. Sugar beets are grown over a rather broad range of soils, and irrigation practices vary widely with different localities. Where the soil is open and the winter season especially dry, winter irrigation is practiced; but where there is sufficient amount of moisture in the soil to start the crop, irrigation may be omitted entirely before the time of seeding. The first irrigation is generally delayed as long as possible, or as long as the beets IRRIGATION 121 are making a steady growth. Two or four applications are usually made during the growing season. The time of these applications is determined by the condition of the plants. Just as soon as they begin to suffer for want of water it is applied. The last application usually comes within four or six weeks before the harvest. This final irrigation is one that requires considerable skill in order that it may be given at the proper time; for if beets are allowed to mature too soon the sugar content will be low. Orchard Irrigation. Orchard irrigation is a general practice in certain regions. This no doubt is due to the fact that irrigation represents intensive agriculture and is well suited to the growing of fruits, both large and small, as the value of the crop per acre is generally large. It is customary in irrigation practice for orchards, to keep the moisture con- tent of the soil high enough to insure favorable conditions for the growth of the trees at all times. Methods vary more in orchard irrigation than in any other. In some localities the practice of thoroughly wetting the soil and conserving the moisture by cultivation prevails. Sometimes pipes or similar conduits are used to give a constant supply of water to the soil. Although the last system is not practiced to any extent, it is common to find it in some localities. QUESTIONS 1 . In what three ways does soil moisture leave the soil? 2. In what kind of soil will moisture losses by seepage be greatest? 3. Discuss four factors that influence the amount of water required in irrigation. 4. Why is thorough wetting better than many light applications? 5. How much water is required for the common crops in the United States, as estimated by Dr. Elwood Meade? 6. Explain the general methods followed in irrigating grain, alfalfa, potatoes, sugar beets, and orchards. CHAPTER XX SUPPLYING WATER FOR IRRIGATION Canals. One of the principal ways of obtaining irri- gation water is by the diversion of natural streams by means of canals. The design and construction of the canals vary widely with localities; but in general the principles involved are the same as those involved in the design of open ditches or drainage canals, which have been considered in a previous chapter. It is customary to compute the capacity of irri- gation canals by Kutter's formula, which is given on page 105. Diversion canals lead the water of a river away from its natural course to the upper side of the area to be irrigated. The essential engineering features of a canal consist in securing such a grade as to insure a sufficient velocity of Pig. 68. Riverside Canal in Colorado before the water was turned in for the first time. This canal where shown is 18 feet wide at the bottom. IRRIGATION 123 flow to get the necessary capacity and to keep the canal clean, or, as usually stated, cause it to "scour." The construction of a canal is an important matter. In the early stages of irrigation practice in the United States, most canals were made with earth embankment, but the increase in the value of irrigation water has led to the intro- duction of methods to prevent waste from the canals by seepage. It is estimated that 47 per cent of the irrigation water now used in the United States is wasted in this way, and in some cases the losses run as high as 85 per cent. Some irrigation canals are ranked among the world's greatest engineering achievements. The Cavour Canal in Europe cost $20,000,000; its waterway is 66 feet wide and 12 feet deep, and it crosses the drainage lines of several rivers. It passes under the Sesia River in a masonry siphon 820 feet long. . There are some large canals in Egypt and India. Among them may be mentioned the Chenab Canal, which is 250 feet wide at the bottom and carries 11 feet of water. The main canal is 400 miles long, and has 1200 miles of tributary canals. It cost $10,000,000, and it is said to irri- gate 2,645,000 acres of land. There are no canals in the United States that will compare with it. The Bear River canal in Utah cost $1,000,000 and waters approximately 100,000 acres. The Modesto-Turlock canal system of California is designed to water 275,000 acres, and cost about $3,000,000. Reservoirs. Reservoirs, either natural or artificial, obtained by the damming or storage of water in natural water courses, are often made the source of supply of water for irrigation purposes, inasmuch as water which would ordinarily be wasted is held in storage until needed. In some localities reservoirs are quite necessary, as streams furnish the minimum amount of water during the time when 124 AGRICULTURAL ENGINEERING irrigation water is needed most. Under other conditions, reservoirs are little needed. Forests are natural reservoirs to the extent that they hold the snow in mountainous countries and prevent a rapid sur- face run-off of the water. In some localities the irrigation water comes from glaciers, which have been found to regulate the supply in a satisfactory and natural way. Thus the maximum amount of water is furnished when the weather is View of the Roosevelt Dam on the Salt River, Arizona. (Bui. 235, Office of Experiment Stations.) hottest and the requirements are the greatest. Sometimes reservoirs are placed at the end of the canal in order that the supply of water may be on hand near the land to be irrigated, so that if a sudden demand for water is made which will exceed the capacity of the canal, the water from the reservoir may be released. Reservoirs have been used in connection with irrigation since very earry times. In India nearly ten million acres of IRRIGATION 125 land are now irrigated from reservoirs. In Ceylon, the Padival Dam is 11 miles in length, and 200 feet wide at the base, 30 feet wide at the crest, and 70 feet high in places. This dam is said to have cost $6,327,100. It is further stated that there are 5000 reservoirs in use in Ceylon. There are many reservoirs in use in the United States, some of which have been built by private, parties, and others by the government. One of the largest of these is the Roosevelt Dam on the Salt River in Arizona. This dam, completed in February, 1910, has a capacity of 1,824,000 acre feet of water. Pumping Water for Irrigation. In many places a supply of irrigation water can not be obtained without the aid of pumps. Usually water secured by this method is very expensive, much more so than the water obtained from canals and reservoirs by gravity. There are, however, certain advantages in pumping the water for irrigation pur- poses. Generally the water supply is under perfect control, which is not always the case with a canal or reservoir. Again, there can be no controversies over water rights or friction with other irrigators who want to use the supply at the same time. Underground water is the only source of supply in certain localities. In some places in the West the soil is so open that large streams disappear and flow away underneath the sur- face. When this water can be pumped it forms a valuable supply of irrigation water. In Egypt much of the water is elevated by hand labor either from canals or from the river Nile. In California alone, over 200,000 acres are irrigated by water which is pumped, and some 400,000 acres are so irri- gated in Texas and Louisiana. There has been a marked development in pumps during the past few decades. The power used includes animal power, steam engines, gas and gasoline engines, and electric power. 126 AGRICULTURAL ENGINEERING The cost of pumping water in certain parts of the United States has been carefully studied by the United States Department of Agriculture. In Santa Clara County, California, the cost of pumping water was investigated at 60 pumping plants. The average amount of water pumped per acre was 1.13 feet. The average cost of fuel and labor was $4.96 per acre, and the fixed charge was $5.20, making the average cost of pumping water $10.16 per acre. The average efficiency of the pumps was 41.16 per cent. It was found that the cost of pumping was reduced by an increase in the size of the plant. The cost of power varies with the cost of the fuel. In some localities the steam engine is cheaper than gas or gasoline engines, and in others the reverse is true. Electricity is more convenient than any other power; but unless it can be furnished through a water power plant or some other cheap source, it is the most expensive. In Arkansas and Louisiana the irrigation water for rice culture is pumped by steam. The following table is the summary of the cost of pumping water at 17 plants in Louisiana and Arkansas, as reported in Bulletin 201, Office of Experiment Stations. The general difference in cost at the Louisiana plants and those of Arkansas is due primarily to the lift or height the water had to be pumped. In the Louisiana plants the lift was about 20 feet, and in the Arkansas plants about 40 feet. Windmills are used quite extensively in certain localities, principally in Kansas and California. An investigation of the cost of windmill irrigation at Garden City, Kansas, indicates that the cost per acre was $2.35. Owing to the fact that power is obtained in small units and the cost of installation and maintenance is very high in the case of wind- mills, it is doubtful if they will be used to any considerable extent. IRRIGATION 127 to O « M 2 CO O CO CJ IM lO CO t^ COrt^iONON CO 1> lO GO CO l> CD t> CD ft 03 oj E OMOIOOhO lO OffiOtOON^ ** CM i-i t-h eq i-i i-i < B J e© ^ CO CO IQ GO 00 ■* iO CD O Oi CM t^ CD CO CO O CM CM ■* --I CM CM CM CM 3 a €© fa ■gE^ co -* co --I •* o oo CD CO CM CM (M O CD Oi CD fa^Q CO i-H CO CO CO CM CM m CM fn e.? CO TO iO CO CO O O TO © TO ^h GO 00 TO lO CO |t oi t> oi oc > t>5 >o !>' iO 2< m OOOiOOUJO (-) ■* O CO t^- rtH CD O lO r- 1 CO CM ^H i-i i-H CM TO *FH *> MO^OO^O CO O CO O O O O CM O Oi ° co co ■* co io io >o o as CM CM~ t}< CO CM CM TO ,_! €© CM fa OCOOiOOhN TO IS "O CO O CM O O0 CM O hi t-~ to r— co i— 1 1> co OI <-i CM CM TO CM aJ id o a > fa 1 CM TO ■* lO CO I-- GO H lift $15.92 9.80 12.19 11.60 10.61 7.10 10.72 13.33 16.20 21.92 CD 1 K? ft-- N^OCSONNOOO CMpiocoGOi-HoqoLOi-H CO TO CM TO CM i-i i-5 ■<* CO "j 95 CD GO' CM o o 3 fa O00CDTO00TO©Tt<-H^ CM CM' ^5 co CM TO «5 lO CO CO TO S so ._ o3 fa.fi o O00 00 00C0O«0C»CSiH OOoOi-HiqpTOCMGOcDOO dTOiO^iOCMCOTO^O €© r-t CM TO o 60 rH ft-- OCM00TOTOOTOCDCD'* © CO •* Oi CO iO i— 1 CO iO CD TO CM ©CMCJcOoicOCicM'l^TO Mnd clearance space. closing tightly. Cleaning will often overcome this difficulty ; but when scored or pitted, the valve must be ground on its seat with emery and oil until a perfect fit is again secured. QUESTIONS 1. What are the four fundamental essentials of gas engine operation? 2. What is meant by an explosive mixtuie? 3. What are some of the difficulties encountered in obtaining an explosive mixture? 4. What are the indications of a rich mixture? A lean mixture? 5. Explain how the quality of the mixture may be tested. 6. How does compression influence the power of an engine? 7. What are the common causes for the loss of compression? CHAPTER LVI GASOLINE AND OIL ENGINE OPERATION (Continued) Ignition. The burning of the fuel in a steam plant is continuous from the time of kindling the fire until the plant is shut down. In the gasoline engine the fire is quickly extin- guished, lasting but a part of one stroke of the piston, necessi- tating the igniting of additional fuel as it is taken into the cylinder. It is easy to see that if for any reason there is a failure to ignite the fresh fuel, no power will be obtained from that particular cylinder. As in the case of failure to secure the proper mixture and compression, the gas engine will not operate unless each charge is successfully ignited. Development. As indicated, the firing of the charge in the cylinder is spoken of as the ignition, and the devices that accomplish it the ignition system. One of the principal diffi- culties encountered by the early inventors in developing the gas engine was that of securing ignition. The early attempts consisted largely in carrying an open flame into the cylinder by means of suitable valves. Later, the hot tube was used generally, and is to some extent at the present time. The hot-tube igniter consisted of a short length of pipe screwed into the compression space and kept at red heat by means of an outside flame. During compression the unburned gases pushed the burned gases up into the tube until the fresh fuel came in contact with the hot surface of the tube, causing ignition. It is not possible to regulate the time of the ignition with the hot tube as accurately as desired, and when used with a small engine, at least, the fuel required to keep the tube hot is often an important part of the entire cost of operation. FARM MOTORS 355 These shortcomings on the part of the hot-tube igniter, and the rapid development of the electric igniter have caused the general abandonment of the former. There are two general classes of electric ignition systems in general use. These systems are generally known as the "make-and-break" system and the "jump-spark" or high- tension system. Each of these systems has its advantages. The make-and-break system is used largely in connection with stationary engines, while the jump-spark is used with variable-speed motors, like the automobile. The Make-arid-Break System. In the make-and-break system of electric ignition two electrodes or points are pro- Itpnilor * S Rod fc&ttery of Dry Cells \^ss\\\\\\\\\\\^^X Fig. 225. Sketch showing the wiring and essential parts of a make- and-break system of ignition. Four standard dry cells form the usual battery instead of six as shown. vided in the compression space of the engine cylinder, and are insulated from each other in such a way that an electric cur- rent will not flow through them unless they are made to touch each other. When an electric current is broken, there is a tendency to produce a spark at the point where the separa- tion takes place. By placing a spark coil in the circuit the size of the spark may be much increased. The system consists S56 AGRICULTURAL ENGINEERING primarily in providing a source of electricity and suitable mechanism to bring the points together at the proper time and to separate them at the proper time for the sparks so pro- duced to fire the mixture in the cylinder. The make-and-break system does not use high-tension or high-voltage electricity. Voltage corresponds to pressure, or ability of the electricity to overcome resistance. For this reason the make-and-break system does not require such careful insulation as does the high-tension system. There are, however, the moving parts inside of the cylinder, and the mechanism operating it is such that it is not convenient to make provision for varying the time of ignition. Failure on the part of the make-and-break system may be generally traced to failure in the source of current, or to a break-down of insulation. There are many other minor causes of failure, but space does not permit a discussion of them here. Testing the Make-and-Break System. When an engine fails to start, a test should be made of the ignition system. — — — , This is generally done by making and break- g* !&.--,. ing the circuit by hand outside of the engine dR| cylinder, and judgment is then passed upon the size of the spark as to whether or not it is sufficient to ignite the charge. After make- a n d-break the insulation on the wires becomes worn and damaged, there may be an escape of electricity without passing through the igniter points. The igniter points may become covered with scale, oil, or dirt which will prevent the electricity from passing from one to the other when desired. Often the movable points fail to work freely, owing to lack of oil, preventing the sharp, quick separation of the points, which is quite necessary to secure a good, fat spark. FARM MOTORS 357 227. Sketch showing the essential parts of a jump-spark system of igni- The Jump-Spark System. The jump-spark system does not have any working parts inside of the cylinder, where they are exposed to the high temperature there present. The mechanism is such that it is convenient to vary the time of ignition when this is used to regulate the speed of an engine, as it is in the case of the automo- bile engine. The jump- spark system requires the use of an induction coil, which, when connected to one of the usual sources of electricity, increases, the voltage to such an extent that when suddenly cut off the new or induced current jumps a small gap. The usual spark plug is only a provision for placing this gap inside of the engine cylinder. Owing to the high voltage of the jump-spark system, certain wires must be very carefully insulated in order that the gap of the spark plug shall be the path of least resistance for the current to escape. Testing. It has been suggested that tests be made with the make-and- break system of ignition to determine whether or Fig. 22S. A jump-spark or induction coil not the System is in WOrk- dissembled to show construction. • i v . t_i mg order when trouble is encountered. A convenient way of testing the jump-spark system is to remove the spark plug and lay it upon the cylinder and manipulate the circuit-breaking mechanism by hand. If a good spark be obtained, it may be assumed 358 AGRICULTURAL ENGINEERING Fig. 229. J spark plug ii section, show ing construe tion. that the trouble lies elsewhere than in the ignition system. The Batteries. Any form of electric ignition requires a source of electricity. One of the most general forms on the market is the dry-cell battery. It represents, perhaps, the cheapest source of electricity, as far as first cost is concerned. When the cells are able to furnish a sufficient quantity of electricity, they are very satisfactory. One of the most perplexing features of the use of dry-cell bat- teries is the matter of determining when the cells are exhausted, as there is no change in the outside appearance. There are instruments, known as ammeters, which enable one to determine how much current a dry cell will furnish ; and where many dry cells are used, this instrument should always be on hand to detect exhausted cells. If an instrument is not available, the strength of the cells must be judged from the size and character of the sparks produced when tested. Storage batteries make a very satis- factory source of electric current for igni- tion, but provision must be at hand for recharging when they become exhausted. Fig. 231. An oscii- Magnetos and Dynamos. Perhaps the lating magneto on ° J ± demonstration stand, most satisfactory source of electric current for gasoline engine ignition is the magneto or dynamo, which is a small instrument for making electricity by me- chanical means. Indications are that it will be only a 230. A storag battery. FARM MOTORS 359 comparatively short time until the magneto will be consid- ered a necessary part of the equipment of the gas engine. At the present time the magneto is regarded as almost a necessity in the operation of the automobile engine. In selecting a magneto or dynamo, care should be taken to see that it is well adapted to the service required and that it is properly installed. Valve Action. The last df the four essentials for the suc- cessful operation of the gas engine is proper valve action, or the correct timing of the valves. It is obvious, after what has already been written on this subject, that the valves must open at the proper time to let the gases into the cylinder, close at the proper time to withhold them for the power stroke, and open again to let the burned gases escape. The suc- tion or inlet valve on farm engines is usually operated by the suction produced by the piston during the suction stroke, and, outside of the adjustment of the light spring which closes the valve, it is self -timing. The exhaust valve should open before the end of the expansion stroke, to allow the free escape of the burned gases, and must close at about the end of the exhaust stroke. The exhaust valve for an average-sized engine is made to open when the crank is about 30° from dead center, but the time will vary with the speed and size of the engine. Directions should be found with each engine for the setting of the valves. 232. dynamo called the Auto- sparker. 360 AGRICULTURAL ENGINEERING QUESTIONS 1. Why is ignition so important to the success of a gas engine? 2. Describe the hot-tube igniter. 3. What are the names of the two systems of electric ignition? 4. Describe the make-and-break system of ignition. 5. Explain how this system may be tested. 6. Describe the jump-spark system of ignition. 7. Explain how this system may be tested. 8. Describe the use of dry cells as a source of current for electric ignition. 9. How does the dynamo or magneto furnish electricity for igni- tion purposes? 10. Why is valve action or timing important? 11. Describe in a general way when the inlet and exhaust valves should open and close with reference to the position of the crank. CHAPTER LVII SELECTING A GASOLINE OR OIL ENGINE The selection of a gasoline or oil engine for the farm is not easy, owing to the many features of the problem involved. First, there is the size or horsepower to be decided; second, the type, involving such features as weight and speed; third, the mounting; and fourth, the quality of the engine. The Size. The gasoline or oil engine is used on the farm for many purposes at the present time, and the power requirements for these various purposes differ widely. The following list gives the more common uses for the gasoline engine and indicates the approximate amount of power required : Washing machine, J^ to 1 H.P. Churn, 1 to ^ H.P. Pump, H to 2 H.P. Grindstone, H to 2 H.P. Electric generator, 1 H.P. or more. Feed mill, 3 H.P. or more. Portable elevator, 3 to 5 H.P. Corn sheller, 2 H.P. or more. Ensilage cutter, 5 to 25 H.P. Threshing machine, 6 to 50 H.P. It is to be noticed that the first four machines require a rather small engine, while the others either require consider- ably more power, or they may be operated more advan- tageously when of a size suitable to a medium-sized engine. The feed grinder may be obtained in almost any size; but where magazine bins are not provided and where it is expected 362 AGRICULTURAL ENGINEERING to give the grinder attention while in operation, a large one is a decided advantage. A grinder using six to twelve horse- power will grind feed at such a rate that one man will have all he can do to provide grain for the hopper and to shovel away or bag the ground feed. Ensilage cutters, when provided with a pneumatic ele- vator or blower, require considerable power, and it is an advantage to have a machine which will take undivided bundles of fodder. To operate such a machine, a 12-horse- power engine, or larger, is required. There are small threshing machines on the market which require little power for their operation, and are no doubt a success where a small amount of grain is to be threshed. The small-sized machines, equipped with the modern labor-saving attachments, such as the self-feeder and the wind stacker, require about 12 horsepower for their successful operation. The other larger machines mentioned may be procured in almost any size to accommodate the size of the engine pur- chased. From this analysis it would seem that there are two classes of work on the average-sized farm which require two sizes of gasoline engines if the work is to be performed economic- ally. A certain portion of the fuel used by an engine is needed to overcome the friction within the engine itself, or to operate it. After enough fuel is furnished to keep the engine in motion, the additional fuel used is converted into useful work. The percentage of the total fuel required to operate the engine proper, when under full load, is not far from 25 per cent for average conditions. Thus it is seen that it will require much more fuel to operate a 12-horsepower engine empty, or under no load, than to operate a 1 ^-horse- power engine under full load. FARM MOTORS 363 The average farm well will not furnish water faster than it could be pumped with a small l*^- or two-horsepower engine; so a larger load cannot be provided by increasing the size of the pump or the number of strokes per minute. The question is often asked, when the purchase of an engine for pumping is contemplated, whether it would not be best to purchase a much larger engine than actually needed in order that it may be used for other work. If the pump- ing is to be continuous, that is, every day, it will be found more economical to buy a small engine to do the pump- ing and a comparatively larger one for the other work. This will be explained by the following calculation: Fuel per year for 1 ^-horse- power engine, light pumping load, 2 hours per day, equals 0.2 gal- lons times 365, or 73 gallons. Fuel per year for 8-horse- power engine, light pumping load, 2 hours per day, equals 0.45 gal- lons times 365, or 164.3 gallons. Difference equals 164.3 — 73, or 91.3 gallons. At 15c per gallon, 91.3 times 15c equals $13.69. This will more than pay for the interest on the cost of the smaller engine, and its depreciation. If the comparison be A special type of engine ;ed for pumping. 364 AGRICULTURAL ENGINEERING made with a larger engine, the difference in the cost of oper- ation would be greater. The Type of Engine. The type of engine to select will depend largely on the kind of service required. If the engine is to be placed upon some horse-propelled machine, like the binder, to drive the machinery, a light-weight engine is highly desirable. Lightest weight may be secured by select- ing a high-speed two-stroke cycle engine. The four-stroke jasoline engine used to operate binder. the machinery of a grain cycle may be made quite light by introducing high rotative speed and using refinement in construction. Usually, high speed is conducive to increased wear and short life. Modern automobile design has, by improved methods and materials of construction, practically overcome the objections to the high-speed engine. FARM MOTORS 365 The average farm machine does not require an extremely steady power, and for this reason the hit-or-miss governed engine is the most satisfactory for average conditions, on account of its simplicity and economy. Where an engine is used for electric lighting, the throttle-governed engine or an engine with extra-heavy fly wheels should be used. The Mounting. The stationary engine has many advan- tages over the portable engine in that it can be better pro- tected and, when mounted upon a good foundation, can per- form its work under the best conditions satisfactorily. The pumping engine should be a stationary engine; it may also perform such other work as may be brought to it. It will prove highly satisfactory to locate the pump house, the farm shop, and the milk house so as to enable the power from one engine to be used in all. The Quality. A poorly constructed and inadequately equipped engine is a bad investment at any cost. A gasoline engine should not only run and furnish power for a time, but it should be so constructed and of such material as to have a long life and require the minimum amount of attention and repair. In considering the purchase of an engine, cognizance should be given to the chief factor which causes the manu- facturer to build a high-grade engine, — namely, the desire to earn a reputation for building first-class goods. The vital parts of a gasoline engine, as of any machine, are those which wear and which must be adjusted and repaired. The following points are important : First, these parts should be provided with adequate lubrication, as it is the principal factor in reducing wear. Second, the size of the parts that wear should be of liberal dimensions and of a good quality of material. Third, the parts should be easily adjusted. Fourth, the parts should be easily replaced when worn out, 366 AGRICULTURAL ENGINEERING Testing. A brake test may be made of the engine to determine the amount of power it will deliver and the amount of fuel required per horsepower per hour. In addition to Fig. 2 35. A gasoline engine arranged for a test. The brake is on the back side. determining the power of the engine, if the test be continued for a time (two hours or longer) an examination may be made of the efficiency of the cooling system and of the FARM MOTORS 367 ability of the engine to carry a full load without any over- heating of the bearings, or other disorders. Estimating Horsepower. The horsepower of a gasoline engine may be estimated from the diameter of the cylinder, the length of stroke, and the revolutions per minute. If these quantities are known for several engines, a comparison of their horsepower may be made. Such an estimate can only be considered approximate, however. A satisfactory formula for estimating the horsepower of gasoline engines of the four-stroke cycle type is as follows : D 2 L R* B.H.P. = ■ 18,000 where D = diameter of cylinder in inches. L = length of stroke in inches. R = revolutions per minute. For two-stroke cycle engines the formula should read as follows : D 2 LR B.H.P. = 13,600 Another formula which has been suggested for vertical tractor engines is: 66 D 2 L Rf B.H.P. = 1,000,000 For horizontal engines the formula is made to read as follows : 75 D 2 L R B.H.P. = 1,000,000 These formulas will agree very closely with the brake horsepower of tractor engines developed in public test. *E. W. Roberts. fW. F. MacGregor. 368 AGRICULTURAL ENGINEERING In selecting an engine, the accessories are often given little attention, when they should be carefully inspected; and if the engine is not well equipped in the way of first-class acces- sories, they should be selected. The lubricating system should be permanently installed and so arranged as to give all working parts a liberal supply of oil. The multiple oil pump is to be highly commended in this connection. Exposed oil holes, which may become filled with dirt and grit, should be guarded against. Summary. The following outline is suggested to aid a purchaser in making a comparison of the merits and value of different engines. The information asked for in this outline should be so obtained from all the engines considered. Things to Consider in Selecting an Engine. Name of engine. Type — stationary or portable. Rated horsepower. Diameter of cylinder. Length of stroke. Revolutions per minute. Piston speed per minute. Calculated horsepower by formula. Cooling system. Frame — construction. Main bearings — construction, accessibility, and adjustment. Cylinder and piston — construction. Crank — const ruction . Gears — construction. Valves — construction and accessibility. Ignition system — construction and protection. Lubrication system — construction and completeness. QUESTIONS 1. What are the principal features to be considered in selecting a gasoline or oil engine? FARM MOTORS 369 2. What will determine the size to be selected? 3. Why is it not economy to use a large engine for light work? 4. How much power is usually required to operate a farm pump? A churn? A washing machine? A feed mill? A corn sheller? An ensilage cutter? A threshing machine? 5. What should govern the type of engine to be selected? 6. Where may a portable engine be used to advantage? 7. What are some of the indications of quality in a gasoline or oil engine? 8. Of what use would a test of the horsepower be? 9. Explain how the horsepower of an engine can be estimated. 10. A four-stroke cycle engine has a cylinder 8 inches in diameter; the stroke is 10 inches long and it operates at 360 revolutions per min- ute. Estimate its horsepower. 11. What are some features to consider in selecting the accessories of an engine? 12. Give a list of the parts that should be inspected in selecting a gasoline or oil engine. Note : — The instructor here should furnish the students with problems in the estimating of the horsepower of engines, perhaps measuring certain engines and comparing the estimated horsepower with manu- facturer's rating. CHAPTER LVIII THE GAS TRACTOR The Utility of the Gas Tractor. The gas tractor — and reference is here made to the tractor with the internal-com- bustion engine — has developed faster during the past ten years than has any other machine used on the farm. On the broad prairies, where the conditions are the most favorable for its use, it is rapidly taking first place over the horse; and in less favorable localities, where intertilled crops are grown, the gas tractor is being successfully tried out. All this has A tmall gas tractor plowing. It may be successfully- operated by one man. taken place despite the fact that ten years ago the gas tractor was an unusual sight. No one reason can be given for this increase in power farming. The new broad open fields of the West, the rapid development of the internal-combustion FARM MOTORS 371 engine, and especially the factor of economy, are suggestive causes. The tractor has been regarded as unwieldy in small fields, but this difficulty has been largely overcome by using the proper system in laying out the lands. One convenient sys- tem is to lay out the fields in lands of such widths as to lose little time in turning at the ends. A strip is left at each side of the field of a width equal to the turning strip at the ends, and sides and ends are turned last by p.lowing around the entire field. The tractor was first introduced for plowing, as this requires more power than any other kind of farm work; but it is also now being generally used in seeding and harvesting. In many instances several of these operations are carried on at the same time. A gas tractor consists of an engine, the transmis- sion, and the truck. These parts will now be discussed under separate heads. The Engine. The trac- tor engine does not differ materially from any other internal -combustion en- gine. No one type of engine has been generally adopted for traction purposes. However, nearly all are of the four- stroke cycle type. The differences in these motors lie in the number of cylinders, the speed of the engine, and the method of governing. The single-cylinder engine has a decided advantage in simplicity. It is easier to manage a one-cylinder than a two- The motor of an oil-burning tractor. 372 AGRICULTURAL ENGINEERING cylinder engine. If the engine is not in proper adjustment there is no tendency to continue to operate it, as there is when there are two or more cylinders, letting the remaining ones furnish more than their share of the power. A multi- plicity of cylinders, on the other hand, for a given power, reduces the magnitude of the impulses and thus to a large extent relieves the gearing of severe shocks. The multiple- cylinder engine furnishes a steady power and is a little more agreeable to operate for that reason. There seems to be little doubt but that greater skill is required to keep the com- plicated engine in proper adjustment and repair. The Clutch. As the gas engine cannot be started under load, it is necessary to have a clutch to engage the engine with gears or with chains and sprockets that transmit the power to the drivers. This Fig. 23S. One form , , . . ... , , .. of clutch. The wood- clutch is generally used to engage a pulley en shoes are force;! . ., . . t ± i • ± _,• outward against the when the engine is used to drive a station- rim of the wheel, i • .,i 1 ix i xi x x* engaging it by fric- ary machine with a belt, when the traction tlon ' gearing is disengaged. In construction, the clutch consists of shoes usually made of wooden blocks, which, by suitable levers, are made to bear against a disk or other surface with sufficient pressure to cause the power to be transmitted through the parts in contact. The form and material of the friction surfaces vary widely. Sometimes the clutch takes the form of two cones, hence the name cone clutch. Again, the friction may take place between a series of disks, one-half of which are attached to the engine shaft and the other half to the trans- mission. This type of clutch is called a multiple-disk clutch, and the disks are usually engaged by the pressure of a spring which may be brought to bear at the most suitable time. FARM MOTORS 373 The clutch is a vital part of the tractor and should be located as close to the engine as possible. The higher the speed at which the clutch rotates the smaller force it will have to transmit. The Gearing. The gears are an important part of the tractor. They should (1) be of liberal dimensions and of great strength; (2) be constructed of such materials as to resist wear to the greatest advantage; (3) be adequately lubri- cated and protected from dirt and grit. Change of Speed. Change of speed is especially desirable with light tractors and is quite necessary where the land is rolling. The load which any tractor will draw is limited by the load it is able to draw up the steepest incline. If a reduction of speed be made for inclines or hills a larger load may be carried continuously. A reverse in direction of travel or a change of speed is accomplished in two general ways : by sliding gears, which is the accepted method now used in automobiles; and by plane- tary gears. The former is the simpler method but is not so convenient of operation. Planetary gears take their name from the gears being fitted to a revolv- ing frame or spider. The Trucks. One of the most important parts of the modern tractor is drivins wheels - the truck, which consists of the frame and the steering and drive wheels. The frame is the backbone of the tractor, and to it are attached the bearings that carry the main axle and the shafts which support the gears. The Steering Wheels. Two methods of constructing the axle of the steering wheels are in common use. In one the The truck for a gas tractor, showing frame, gearing-, and steering and 374 AGRICULTURAL ENGINEERING axle is pivoted at the center, and steering is accomplished by revolving the axle about this pivot or king bolt. The main advantage of this system is that the steering wheels may be turned while the tractor stands still. In the other style the axle is pivoted just inside of each steering wheel and each wheel is turned about its own pivot. This style of steering mechanism is easy to handle while in motion. It is quite positive, that is, there is no slack to take up in the chains, and it is of more rapid action than the other style. The Traction Wheels. The traction wheels should be carefully considered in making a selection of a tractor, because certain wheels are adapted to certain conditions. If the ground over which the tractor must pass be soft, it is highly desirable that both the drive and the steering wheels be as high as practical. Wheels of large diameter present a larger section of their periphery to the surface of the ground, and so cut in but slightly. Extensions are provided by all manu- facturers for making the drive wheels wider for work in soft ground. Where the soil is exceedingly soft, the cater- pillar tread or creeping grip should be used. It is possible to use this type of tractor in marsh or swamp soils or over sand where it is impractical to use horses. The Equipment. Too much emphasis cannot be laid upon the importance of securing a tractor which is well equipped. Often there is a serious loss of time resulting from the poor quality of parts that cost but a few cents. A purchaser should see that the tractor has modern high-class ignition, carburation, and lubrication systems. QUESTIONS 1. What are some of the conditions under which the gas tractor can be used with economy? FARM MOTORS 375 2. To what kinds of work is the present gas tractor adapted? 3. What are some of the advantages and disadvantages of the multiple-cylinder engine for a tractor? 4. Why is the clutch an important part of the gas tractor? 5. Describe the differences in the shoe, cone, and multiple-disk clutches. 6. Why is the gearing an important part of a gas tractor? 7. How may a change of speed be accomplished? 8. What is the purpose of the frame? 9. Describe two styles of steering wheels. 10. Discuss the construction of traction wheels. 11. Why should the equipment of the tractor be given careful con- sideration? CHAPTER LIX THE STEAM BOILER The Steam Power Plant. A steam power plant consists essentially of two parts, the steam boiler, for generating steam by the combustion of fuel ; and the steam engine, which con- verts into work the energy contained in the steam. It is customary, however, to refer to the entire steam plant as the steam engine, when the plant is small. When the boiler and engine are mounted on wheels and arranged with suitable gearing for propelling itself as well as for drawing loads, the outfit is referred to as a traction engine. Of late years it has become customary to refer to the steam traction engine as the steam tractor. The subject of the steam power plant will be divided into three parts, confined to as many chapters, as follows: the steam boiler, the steam engine, and the steam tractor. At one time the steam engine as denned above and the steam tractor were the principal sources of power for agricultural purposes, when large units were required. The development of the internal-combustion engine and tractor has been more rapid in recent years than that of the steam engine and tractor. The Principle of the Steam Engine. The steam engine is a heat engine, in that its function is to transfer the heat pro- duced by the combustion of fuel, usually wood or coal, into mechanical energy. It might be styled an external-combus- tion engine, in that combustion takes place outside of the boiler proper and the heat is absorbed by passing the hot gases through tubes surrounded by water. FARM MOTORS 377 In an open vessel water cannot be heated above the boil- ing point of 212° F., but heat continues to be absorbed and is used in the formation of vapor. Water under pressure boils at a higher temperature. Thus if the pressure inside the con- taining vessel were two pounds greater than atmospheric pressure, the boiling point would be about 228° F. Changing water into vapor increases its volume many fold. At atmos- pheric pressure the volume of the vapor is about 1700 times that of the liquid. At 100 pounds pressure the volume of the steam is about 240 times the volume of the liquid. Water vapor, or steam, is a colorless gas which obeys all of the laws of gases as far as expansion and change of temperature are concerned. Functions of a Boiler. The functions of a boiler are to absorb heat from the hot gases produced by the burning of fuel and to transmit it to the water contained within, causing it to vaporize into steam. The steam boilers used in agricul- tural plants and in traction engine service include the firebox, or furnace, which may be placed either directly underneath the main part of the boiler or entirely within it. Location of the Furnace. Boilers with the fire box out- side of the boiler proper are called externally-fired boilers. This type can safely be used for stationary work and are usually set in brick work, which forms a large part of the furnace. Those which have the furnace within the main body of the boiler, or shell, as it is called, are said to be inter- nally-fired boilers. Most of the boilers used in agricultural practice and all of the boilers used for traction engine service are internally fired. The Vertical Boiler. The vertical boiler is used in small units and where space is especially valuable. It consists of a cylindrical shell containing a furnace in the lower end, over which is placed a tube sheet or plate and a system of tubes. 378 AGRICULTURAL ENGINEERING These boilers are not considered very durable and are quite difficult to clean properly. The Locomotive Type of Boiler. The locomotive type of boiler is the one most generally used for trac- tion engine service. It consists of a fire box made of steel plates, in which the furnace is placed; a cylindrical shell extending forward, containing a comparatively large number of tubes; a smoke box at the front end; and a stack to carry the smoke away. The fire box is almost entirely surround- ed with water. The plate directly above the fire is called the crown sheet and the plates Fig. 240. A vertical boiler, vaive; '£, try forming the sides of the box are called side cocks; C, injec- , , x „ , tor; d, hand sheets. In some instances lire boxes are so hole; E, pressure gauge; F, gauge glass; G, fire door; H, ash door. made as to have water beneath the grates; such a boiler is said to have a water bottom. The boiler has a cylindrical chamber riveted to the top of the shell, in which the steam collects and from which it is drawn to the engine. This part is called the steam dome, and is a device for drying the steam. All parts of the boiler are made of the best steel plates, and the seams are carefully riveted together. The joints are made Fig. £41. A boiler of the locomotive type in section: A, steam dome; B, smoke box; C, fire box; D, grates; E, tubes; F, crown sheet. FARM MOTORS 379 tight by calking or battering the edges of the seams down with a special tool designed for the purpose. The flat plates of the fire box are supported by bolts or studs running from one plate to the other. These are called stay bolts, except those over the crown sheet, which are called crown bolts. The boiler is usually provided with a valve at the lowest point, which may be opened to allow any sediment in the boiler to be blown out. In the management of the locomotive type of boiler, great care should be taken to keep the water over the crown sheet at all times. Return-Flue Boilers. The return-flue boiler has a large cylindrical shell in which a comparatively large flue is placed, large enough to contain t *** E % the furnace. The heated l^M gases pass to the front end 4^1 tubes to the smoke box in ifess £u^— ; — - — -111 the back end. One ob- ;i ~_ ' \ ^^^^ggggp^a^---, : jection to this type of boiler <3C9 i?t3fc3«J0e3 (5« © «3 ©<« o /fH l_l l«* SH M / Gbrnrrv 1 GrRRDEN Fig. 253. An inconvenient arrangement of farm buildings. field should be designated by a particular name or number and the exact acreage indicated. Such a map is extremely useful in planning the operations of the farm, the rotations, and in calculating the amounts of fertilizers, seed, etc. 398 AGRICULTURAL ENGINEERING To illustrate the great differences to be observed in farm- stead plans, attention is called to the two accompanying sketches. The first of these (Fig. 253) is the plan of a farm- stead just as it is at the present time. To do the morning chores on this farm, — tending to the horses, cows, and hogs — it is necessary to walk 2400 feet outside of the buildings. Besides this bad feature notice how inconveniently the garden is placed from the house. The well, also, instead of being be- tween the house and barn, is beyond the barn. Compare this plan with the next. The house is 150 feet from the road and the barn 200 feet from the A GOOD flRRRNGEMENT . from Town « Morftinq Work - To Fields •-.. Cows Horses. IS PlJBUO HvOHWRY. Fig. 254. A good arrangement of farm buildings. The lines of travel in doing the work of the farm are indicated. house, which is not too close when located in the right direction. The prevailing winds are either from the northwest or south- east, and the odors from the barn are seldom carried toward the house. The implement and wagon shed also includes the shop and the milkhouse. If the well could be located near this shop, so much the better, as at this point a gasoline engine could be used to do all the light work. In doing the morning work, a man needs to walk only 900 feet, a saving of 1500 feet over the former plan. FARM STRUCTURES 399 Principles of Location. In locating the farm buildings, it is well to incorporate as many as possible of the following principles in the plan : 1. Have the buildings near the center of the farm, giving due consideration to other advantages. 2. Needless fences should be avoided, on account of first cost and the cost of maintenance. 3. A pasture should be adjacent to buildings. 4. The buildings should occupy the poorest ground. 5. The buildings should be located with reference to the water supply. 6. The buildings should be on a slight elevation when- ever possible. 7. A southwest slope is desirable. 8. The soil on which buildings are to be placed should be dry and well drained. 9. A timber windbreak should be secured. 10. A garden plot should be near the house. 11. The buildings should not be located on high hills, because of difficulty of access from fields and roads. 12. The buildings should not be placed in low valleys, on account of the lack of air and good drainage and the danger from frost. 13. The buildings should be located on the side of the farm nearest the school, church, or town. 14. The house should not be less than 100 feet from the highway. 15. The barn should be about 150 to 200 feet from the house, and not in the direction of the prevailing winds. 16. The barn should be in plain view from the house. 17. The lots should be on the farther side of the barn from the house. 18. Several views from the house are desirable. 400 AGRICULTURAL ENGINEERING 19. All buildings should serve as windbreaks. 20. The shop and machine shed should be convenient to the house, the barn, and the fields. Two general systems of arranging farm buildings have been developed in this country. For want of better terms, they may be designated as the distributed system, in which a separate building is provided for each kind of stock or for each purpose to which it may be devoted; and the concen- trated system, in which everything is placed under one roof as far as possible, or the buildings are at least connected. The advantages of the first system may be stated as follows : 1. A greater amount of lot room is possible. 2. Different kinds of animals are separated. 3. There is less destruction in case of fire. 4. It is more economical for the storage of certain crops and machinery. 5. Better lighting is secured: wide barns are necessarily dark. In turn, the following arguments may be advanced for the concentrated system: 1. The first cost is less: needed space is secured with the minimum of wall surface. 2. There is less expense for maintenance. 3. It is more economical of labor. 4. Better fire protection can be provided. 5. Manure can be handled to the best advantage. 6. It provides a very imposing structure. It is to be expected that opinions and tastes will differ, as well as conditions, and all of these will determine the best arrangement for any particular location. Most farmsteads are the result of growth and development, and for this reason are not what they would be if built entirely at one time. As changes are made and new buildings constructed it is well to FARM STRUCTURES 401 keep in mind the desired features and to approach the ideal as far as possible. In commercial life it has often been found a matter of good business to dismantle certain buildings designed for manufacture and entirely rebuild them. There are, no doubt, many farms so equipped that it would be a good business investment to entirely dismantle the existing buildings and rebuild in such a way as to insure a more economic operation. QUESTIONS 1. Give four reasons why the study of farm structures is impor- tant. 2. What percentage of the fixed capital of the farm is invested in farm buildings? 3. Explain how a convenient arrangement of farm buildings con- serves labor. 4. In what way will comfortable buildings conserve feed? 5. How is the quality of dairy products influenced by the character of the farm buildings? 6. Upon what general conditions will the layout of the farm depend? 7 What are the principal features to be desired in the layout of a farm? 8. What are some of the principles involved in laying out the farm? 9. Discuss the distributed system of farm buildings. 10. Discuss the concentrated system of farm buildings. CHAPTER LXII1 MECHANICS OF MATERIALS Definitions. Mechanics is that science which treats of the action of forces upon bodies and the effects which they produce. Statics is that division of the science of mechanics which treats of the forces acting on a body at rest, or in equilibrium. In architectural design, statics is the principal branch of mechanics to be considered, as nearly all the forces involved are those of rest. Action of a Force. A force acting upon a body tends to produce motion in two ways: 1. It tends to produce motion in the direction of the force. 2. If a point of the body be fixed, it tends to produce motion about that point. Condition of Equilibrium. Since a force acting upon a body tends to produce motion in two ways, the following conditions must be filled in order that equilibrium exist : 1. The resultant of all the forces tending to move the body in any direction must be zero. 2. The resultant of all the forces tending to turn the body about any point must be zero. The moment of a force about a point is the product of the force into the perpendicular distance from the line of the force to the point. Moments tending to produce clockwise rotation are called positive moments, and those tending to produce counter- clockwise motion, negative moments. FARM STRUCTURES 403 Tension Fig. 255. A sketch illustrat- ing a tensile stress. -ten- Equilibrium of Moments. The forces acting upon a body are in equilibrium when the algebraic sum of their moments about any one point is equal to zero. Stress. A stress is the resistance offered by a rigid body to an external force tending to change its form. A rope suspending a weight is under stress. If a section of the rope be taken at any point, the force exerted by the part of the rope on one side of the section on the part on the other side to prevent the rope from part- ing or breaking, is termed the stress at a section. The word strain is often used incorrectly for stress, but strain is the change of form pro- duced by a stress. Simple stresses are of three kinds, sile, compressive, and shearing. Stresses are measured in pounds or tons in countries using English units. The pound is the more often used. Tensile stresses are those tending to pull the object or material in two, or to stretch it. A rope suspending a weight is under a tensile stress. A tie rod in a truss is subjected to tensile stress. Compressive Stresses. Compressive stresses are those tending to crush the object or ma- terial, as the load that is placed on a column or on a foundation. Shearing Stresses. Shearing stresses are those tending to slide one portion l t fi -, - h — , T fc — , , of the material over another, or Fig 257 A sketch ilUlstrat . when there is a tendency to cut. in » a shearing stress. The stress on riveted joint is a good example. Complex Stresses. Complex stresses are those formed by a combination of simple stresses. The stresses in beams are usually complex. Compression Fig. 256. J sketch illustrat ing a compres sive stress. 404 AGRICULTURAL ENGINEERING Unit stress is the stress per unit area. Stresses are usually measured in pounds, and areas in square inches. The total stress divided by the area of cross section in square inches will give the unit stress. S ~ A when P = total stress in pounds. A = area of cross section in square inches. S = unit stress. This rule is applied only when the total stress is uniformly distributed and the stress is a simple stress. Elasticity. Most bodies when subjected to a stress will be deformed. The amount the body is changed in shape is termed the deformation. An elastic body will regain its former shape when a stress is removed, if it has not been too great. Up to a certain limit the amount of change in shape is proportional to the stress. If the unit stress be increased to such an extent that the material will not regain its original shape after being deformed, the stress has passed beyond the elastic limit of the material. Ultimate Strength. If the unit stress of any material be increased until rupture or breakage occurs, the stress pro- ducing the failure is the ultimate strength of the material. If the failure be produced by the tensile stress, the ultimate tensile strength is obtained. In like manner the ultimate compressive and shearing strengths are obtained. The breaking load divided by the original cross section gives the ultimate strength. Working Stress. The greatest stress allowed in any part of a framed structure is called the working stress of that part. In turn, the working strength of a material to be used for a certain purpose is meant the highest unit stress to which the material ought to be subjected when so used. FARM STRUCTURES 405 Factor of Safety. The factor of safety is the ratio of the ultimate strength to the working stress of a material. f-S s when S = ultimate strength, s = working strength, f = factor of safety. The engineer in charge of design is called upon to decide the factor of safety to be used. The factor of safety should (1) be much below the elastic limit, (2) be larger for varying loads, (3) be larger for non- uniform materials. Factors of safety for various materials. Materials For steady stress. Buildings For varying stress. Bridges For shocks. Machines Timber Brick and stone Cast iron Wrought iron. . Steel 15 6 4 5 10 25 15 6 7 15 30 20 10 15 This table is taken from an architect's handbook, and the factors of safety here recommended are nearly twice as large as are commonly used in designing farm structures. QUESTIONS 1. Define mechanics. Define statics. 2. In what two ways does a force acting on a body tend to produce motion? 3. What are the two conditions for equilibrium? 4. Define moment of force. 5. When does an equilibrium of moments exist? 6. Define stress. Define strain. 7. Describe a tensile stress. A compressive stress. A shearing stress. A complex stress. Define unit stress. 8. Explain what is meant by the elastic limit of a material. 9. Define ultimate strength. Working stress. Factor of safety. 10. Upon what conditions will the size of the factor of safety depend? CHAPTER LXIV MECHANICS OF MATERIALS AND MATERIALS OF CONSTRUCTION The Strength of Beams. The strength of a beam or its ability to support a load depends upon three principal factors : (1) The way the beam is stressed, or the way the load is applied or distributed and the beam supported; (2) the way the material is arranged; and (3) the kind of material. These factors are represented by the maximum bending moment, the modulus of section, and the modulus of rupture. The Bending Moment. The bending moment is a meas- ure of the stresses acting on a beam. Suppose a beam to be fixed solidly at one end, as would be the case if it extends into a solid wall, and a load or a weight to be suspended at the extreme end, as shown in Fig. 258. It is to be noted that the greatest stress in the beam would be at the point where it enters the wall. The force would tend to rotate the beam about a point in the beam where it enters the a cantilever iam,'* fbl&m wall. The stressesproduced would tnf^forofa y .oad 0n a e t e the'f a r n ee tend to pull the material in two end " at the upper side and to crush it on the lower. If the weight be placed somewhere between the wall and the end, the stress on the beam would be less than in the first instance; in fact, the stress would be in direct proportion to the distance from the wall to the weight. The stress would also be in direct proportion to the size of the weight. Thus the tendency to break the beam, or the FARM STRUCTURES 407 stress at the wall, would be twice as great for a 20-pound load as for a 10-pound load. It is to be noticed that the stress would be greater at the point where the beam enters the wall than at any other point; or, in other words, the maxi- mum bending moment would exist at that point. Expressed in the form of a formula: B M = W L where B M is the maximum bending moment, W the weight, and L the length of beam in inches. If the beam be supported at both ends or extend into the wall at both ends, the maximum bend- ing moment would have an entire- ly different value; thus, for a tJ&A . A o£2^K2d3[ beam resting in supports at both the center of a simple beam - ends with a load at the center, BM=MWL If the load be uniformly distributed over the beam, then B M = y 8 W L The Modulus of Section. It is generally known that a 2x4 piece of wood will support a greater load when placed on edge than when laid flat. The modulus of section is simply a measure of the strength of a beam according to the arrange- ment of the material. Thus, for a beam with a rectangular cross section, bd 2 M S = — 6 where M S is the modulus of section, b the width of the beam in inches, and d the depth of the beam in inches. Thus it is seen that a 2x4-inch beam is twice as strong when set on edge as when laid on the flat; for, when placed on edge, bd 2 2X(4X4) 32 M S = — = -= — 6 6 6 408 AGRICULTURAL ENGINEERING If placed on the flat, bd 2 4X(2X2) 16 M S = — = =— 6 6 6 or just one-half of the value previously obtained. The Modulus of Rupture. The modulus of rupture is a measure of the strength of the material to resist transverse or bending stresses. Thus oak is stronger than pine. The modulus of rupture is obtained by test. The following table furnishes the values of the modulus of rupture quite generally used. All of the values are per square inch of cross section. White pine 7,900 Yellow pine 10,000 Oak 13,000 Hickory 15,000 Cast iron 45,000 Mild steel 55,000 Formula for Beams. The general formula for beams may now be stated as follows: modulus of selection X rupture modulus Bending moment = : — ; : — — i actor oi satety This formula may be used in calculating the strength of beams, but it is given here principally to explain how the strength of beams varies. The following tables give the strength of columns or posts and of beams. Safe Strength of White Pine Beams. The following table gives the safe loads for horizontal, rectangular beams Span in feet Depth of beam 6 8 10 12 14 16 6 720 540 432 360 308 7 980 735 588 490 420 8 1280 960 768 640 548 480 10 2000 1500 1200 1000 857 750 12 2880 2160 1728 1440 1234 1080 14 3920 2940 2352 1960 1680 1470 FARM STRUCTURES 409 one inch wide with loads uniformly distributed. If the load be concentrated at the center, divide by two. For oak or Northern yellow pine, the tabular values may be multiplied by 1%; f° r Georgia yellow pine, by 1%. For a discussion of the materials used in the construction of farm machinery, see Chapter XXXI. Safe Load in Pounds for White Pine or Spruce Posts.* Size of post Length of post in feet in inches 8 10 12 14 16 4x4 4x6 5}4 round. 6x6 6x8 6x10 7}4 round. 8x8 8x10 8x12 9}4 round. 10x10 7,680 11,520 12,350 19,080 25,440 31,800 24,220 35,450 44,320 53,180 40,000 62,500 7,033 10,550 11,730 18,216 24,290 30,360 23,380 34,300 42,480 51,450 39,000 55,400 6,533 9,800 11,180 17,352 23,140 28,920 22,540 33,150 41,440 49,730 37,860 53,960 8,700 10,490 16,490 21,980 27,480 21,660 32,000 40,000 48,000 36,800 52,520 15,620 20,830 26,040 20,820 30,850 38,560 46,240 35,730 51,080 Oak and Norway pine posts are about one-fifth stronger, and Texas pine and white oak are one-third stronger. Stone. Limestone and sandstone are the kinds of stone generally used for building purposes. Granite is used to a limited extent. Limestone is the most common stone used, and when dense and compact is very durable. It often con- tains certain substances which cause the stone to become badly stained after being in use for a time. Limestone has an average compressive strength of about 15,000 pounds per square inch and weighs from 155 to 160 pounds per cubic foot. *Kidder's Pocket Book. 410 AGRICULTURAL ENGINEERING Sandstone of a good grade is an excellent building mate- rial. It has a strength of about 11,000 pounds per square inch and weighs about 140 pounds per cubic foot. The densest and strongest stones are the most durable, as a rule. A good stone will not absorb more than 5 per cent of its weight of water when soaked in water for 24 hours. Brick. Brick is a material quite generally used over the country, and when of a good quality is quite satisfactory. Brick should be of uniform size, true and square, and when broken should show a uniform and dense structure. Good brick will not absorb moisture to an extent greater than 10 per cent of its weight, and the best will absorb less than 5 per cent. The crushing strength of brick should exceed 4000 pounds per square inch. Hollow clay blocks or tile are made of the same material as brick, and should have the same characteristics. Clay blocks are lighter than brick, and so the cost of shipping is less. They cost less by volume, and more wall can be laid in a given time than with common brick. Lime. Lime is used in mortar where the greater dura- bility and strength of cement mortar are not needed. Quick lime should be in large lumps and should be free from cinders and dust. When slackened with water it should form a smooth paste without lumps or residue. Lime mortar is usually made of 1 part of lime to 2 or 3 of sand. Portland Cement. Portland cement is now generally used in the making of mortar and concrete. It should be finely Fig. 260. Hollow clay building' blocks. FARM STRUCTURES 411 ground and should set or harden neither too quickly nor too slowly. It should show a high tensile strength when hard- ened and sufficiently aged. It should not check, crack, or crumble upon hardening. Where cement is to be used in considerable quantities it should be carefully tested by standard tests. Sands. Sand should be clean, durable, coarse, and free from vegetable and other foreign matter. Coarse sand is preferable to fine sand because the percentage of voids or open space between the sand grains is less. Concrete. In a general way concrete consists of mortar in which there is imbedded more or less coarse material, like 3JA/0 STOMf COA/C/?£T£ Fig. 261. Material required to make concrete to the proportion of 1 part of cement, 2 parts of sand, and 4 parts of broken stone. gravel or broken stone, called the aggregate. Thus it is seen that if the aggregate be good, durable material and the mortar be sufficient in quantity to surround all of the aggregate, the whole will be as strong as the mortar. In preparing concrete, therefore, it is desirable to obtain as dense a mixture as is practical. The mixtures indicated in the following table are in com- mon use, and the amount of material required to make a cubic yard of concrete in each case is also given. A rich mixture is used for beams, columns, and water-tight constructions. 412 AGRICULTURAL ENGINEERING Material for one yard of concrete of different proportions. Mixture Proportions Cement, bbls. Sand, bbls. Gravel, bbls. Rich 1:2:4 1:2^:5 1:3:6 1:4:8 1.57 1.29 1.10 .85 3.14 3.23 3.30 3.40 6.28 Medium Ordinary Lean 6.45 6.60 6.80 Additional data: 1 bbl. of Portland cement weighs 376 lbs.; a sack, 94 lbs. A barrel contains 3.5 cu. ft. between heads. Concrete weighs about 150 lbs. per cu. ft. A medium mixture is used for thin foundation walls and for floors and sidewalks. An ordinary mixture is used for heavy walls which ar not subject to heavy strains. A lean mixture is used for heavy work where the material is subjected to only compressive stresses. Reinforcement. Concrete is a very good material to carry compressive stresses. Concrete and steel have very nearly the same coefficient of ex- pansion for changes in tempera- ture. This makes possible the use Fig. 262. sketch showing of a combination of j these mate- the proper location of steel in a concrete slab to resist tensile rials to the very best advantage stresses due to bending. . , .. .. . _, m building construction. the steel is placed in position to resist tensile stresses to the best advantage, and the concrete is poured around it. When used economically the cross-sectional area of the steel is equal to 34 to 1 per cent of the cross-sectional area of the beams. The steel is usually placed from % to 1 inch be- neath the surface of the concrete, in order to be thor- oughly protected from corrosion. Cj"->c^e£e Se 1 _^_ FARM STRUCTURES 413 QUESTIONS 1. Upon what three factors does the strength of a beam depend? 2. Define maximum bending moment. 3. What is the maximum bending moment for a beam 120 inches long and loaded at the center with 1000 pounds? 4. Define modulus of section. 5. What is the modulus of section for a 2x6? 6. Define modulus of rupture. 7. What is the modulus of rupture for white pine? Oak? Cast iron? 8. Give the general formula for beams. . 9. What load will a 2x6 white pine beam carry if the beam be 10 feet long and the load be concentrated at the center? If the load hi uniformly distributed? 10. Give the principal characteristics of the following building materials: stone, brick, lime, Portland cement, sand, concrete. 11. Explain rich, medium, ordinary, and lean mixtures, and the use of each. 12. Explain the principles involved in the reinforcing of concrete. CHAPTER LXV HOG HOUSES Essentials. The essentials of a good hog house are warmth in winter, coolness in summer, dryness, good ventila- tion, and adequate light. In addition it should be so arranged and located as to be convenient not only for caring for the animals but also for securing pasturage. A building which thoroughly protects the hogs from the wind and moisture is considered warm enough for all but the colder climates. Far- rowing houses must, of course, be made warm. Location. Drainage is highly important, and a well- drained location should always be selected. If the soil is of a porous or gravelly nature, it will make a more desirable site. Types of Hog Houses. There are two general types of hog houses in common use. The first type is the individual or colony hog house, or cot, as it is sometimes called, which is usually made portable and of sufficient size to accommodate one sow at farrowing time or one litter of pigs as they grow to maturity. The second type is the large or concentrated hog house, sometimes called the combined hog house, or piggery, and pro- vides several pens under one roof. This type of building is of more elaborate construction, and in many instances special care is used in the construction to secure a warm building for farrowing early litters. Advantages of the Colony House. There is much differ- ence of opinion, even among practical hog raisers and breed- ers, in regard to the relative merits of the two types of hog FARM STRUCTURES 415 houses which have been described. The advantages of the individual or colony house may be summarized as follows : 1. Each sow is free from disturbance at farrowing time. 2. Each litter is reared by itself, and too many pigs are not placed in a common lot. 3. The house may be placed at the opposite end of the lot from the feed trough, thus requiring the hogs to exercise. 4. There is less danger of spreading disease, owing to the fact that each family is quite effectively isolated. 5. If the location of the house becomes unsanitary, it may be moved. Advantages of the Large Hog House. The following advantages may be claimed for the large or concentrated hog house. 1. This type is almost essential for early litters in north- ern climates. It is possible to construct a warmer building to begin with, and, if necessary, artificial heat may be provided by means of a stove or heating plant. 2. It saves time in handling and feeding the pigs. In other words, less time is lost going from pen to pen. The distribution of feed and water becomes a big task where there are many pens to look after and where they are located at some distance from one another. 3. The concentrated house saves fencing. 4. The large house is generally of more durable con- struction and of better appearance, adding thereby to the value of the farm. 5. It permits of larger pastures, which are more con- venient to renew or cultivate when rotated with other crops. Both types of houses are successfully used by practical men, and the type to be chosen must depend upon local condi- tions and individual tastes. 416 AGRICULTURAL ENGINEERING Dimensions. A farrowing pen should contain from 40 to 140 square feet of floor. A common size is 8 by 10 feet. Stock hogs should have 6 to 12 square feet of floor, varying with their age. A farrowing pen usually has an outside pen, also, having an area of from 128 to 160 square feet or more. &- 0"- Front elevation of the "A" type of colony or portable hog house. (After Wisconsin Exp. Sta.) The cubic feet of air space per hog is not taken into consider- ation. Portable or individual hog houses are usually 6 by 8 feet or 8 by 8 feet. When ventilating flues are provided, about 8 square inches of cross section should be provided for each grown animal. FARM STRUCTURES 417 THE INDIVIDUAL HOG HOUSE Construction. The individual hog house is constructed in a variety of shapes, of which the more general are the A-shaped house and the shed- and the gable-roofed houses. There does not seem to be a great difference in the merits of one shape over the other. The A-shaped house has the walls and roof combined. It is usually made of 1x12 boards, with the cracks covered with battens. The door should be about 2 feet wide and 2 feet 6 inches high. A small window is usually located at each end of the house. A small ventilator in the ridge of the roof is desirable. It is recommended that the door be covered with burlap to prevent drafts in cold weather. Some breeders — H >r-\ z=z\==: i i r-6'-l % "=! ;rr— j^&- -8-0' Fig. 264. Side elevation of the house shown in Fig. 263. 418 AGRICULTURAL ENGINEERING gbcfof/i/S' g&rn Boards prefer a cloth covering for the windows in place of window glass. This type of house is generally built on skids or runners, which facilitate its moving from one location to another. These runners may best be made of 4 x 6 pieces, although 2x6 pieces are quite often used. Reinforced concrete skids have been used successfully for portable houses and have the advantage of being free from decay. Shed-roof House. The shed-roof house takes more material than any other shape, and is not generally made. The floor, sides, ends, and roof may be so made as to be taken apart for moving. Such construction might be an advantage where the house is to be moved a long distance; otherwise the use of skids would be far more conven- ient. Gable-roof House. The gable-roof portable house has many advantages, the principal one being the convenience of having cer- tain sections of the roof arranged for opening during mild weather and allowing the direct sunlight to enter. This can be done more effectually when the house is located east and west and a section of the south half of the roof is made to open. One or both of the sides may also be placed on hinges to open during warm weather. This house is built on skids, and should be provided with the window and burlap curtain like the A type of house. Fig. 265. Eno Vt&w End elevation of colony hog house. FARM STRUCTURES 419 THE LARGE OR CONCENTRATED HOG HOUSE Large hog houses, as distinguished from the colony house, vary largely in the arrangement of the windows, or the natural lighting. The value of direct sunlight in the hog house is generally appreciated. Construction. Houses are usually located so as to extend east and west, and when so located should have the half- monitor or saw-tooth type of roof. The windows of this type are so arranged that those in the lower row permit the sun to shine into the first row of pens, and the upper row into the row of pens on the north side of the building. Hog Fig. 266. A floor plan of a large hog house. houses built to extend north and south usually have gable roofs, and a row of windows on either side. There is much difference of opinion in regard to the rela- tive merits of these two types of roofs. It is safe to say that either will prove entirely satisfactory when properly con- structed. The half-monitor roof requires more material than the gable-roof house. The upper part of the building is solely for the purpose of letting sunlight into the black pens. Such construction prevents the proper control of the temperature, as there is a large pocket above into which the warm air may lodge. The back rows of pens with this construction is shaded more or less throughout the entire year. The open- 420 AGRICULTURAL ENGINEERING ings on the north side of the building are criticised severely by some as being highly undesirable. On the other hand, the principal redeeming feature of this type of house is that the windows may be placed so as to do the most good. The half-monitor roof is usually built about 24 or 30 feet wide. It is desirable that the alley-way be 8 feet wide, to permit a team and wagon to be driven through the house when desired. The pens at either side may be from 8 to 12 feet Fig-. 267. A cross section of a hog house with half monitor roof. This is located so as to extend east and west. deep and about 8 feet wide. Fig. 267 shows a cross section of a house with the windows well arranged. A cross sectionof a gable-roof hog house is shown in Fig. 278. The sunlight enters the east windows early in the morning and travels across the floor, as the sun rises higher, until nearly noon, when it is excluded until it begins to shine in through the west windows. It is to be noticed that this type of house uses less material than the first, owing to the fact that there is not so much space in the upper part of the house. FARM STRUCTURES 421 The lighting of this type of house is sometimes augmented by building a monitor above the alley-way and supplying two additional rows of windows. This construction adds con- Fig. 268. Cross section of a hog house with gable roof. siderably to the cost. A type of house which is being used and developed in Iowa is one with a skylight running through- out the entire length of the building. This system of lighting Green- house Vyindow. Fig. 269. Cross section of a hog house with a sky-light in the roof. Direct sunlight strikes all parts of the floor during the day. 422 ■ AGRICULTURAL ENGINEERING is obviously the best of all, as a solid band of sunlight must pass across the building every day, striking every part. With windows, only spots of direct sunlight enter the building, and even when great care is used in the design of the building this light strikes but a relatively small proportion of the total floor space. With this new type, the only portion of the entire building not covered is the south end, and windows may be provided to light this portion thoroughly. The objection has been raised that this skylight would be damaged by hail. An investigation shows that the loss of greenhouse glass is not great, and it would be possible to pro- tect the glass with a wire net if thought best. This construc- tion is the cheapest of all, as the building may be built quite low and the cost of the sash for the skylight is not much greater than the cost of regular roofing materials. In some instances it may be necessary to arrange a shade under the skylight if the house is to be used much during the summer months. The Foundation. The foundation of a hog house need not be heavy. A 6-inch concrete wall or an 8-inch brick wall will be found adequate if placed on a 12-inch footing. The foundation should extend below the. frost line if the building is to retain its shape well. Floors. Earth, plank, and concrete are used for the hog house floors. Earth is objectionable on account of the diffi- culty of cleaning the house thoroughly. Plank is not desir- able, for it furnishes a harbor for rats. Concrete makes a very desirable floor but has the objection of being cold. Many practical breeders find that this objection has little weight if the floor be placed upon thoroughly drained soil and the hogs are provided with a liberal amount of bedding. A portion of the floor may be covered with boards. The usual sidewalk construction should be used for concrete floors. FARM STRUCTURES 423 Walls. Drop siding upon 2x4 studding two feet on center is usually used for the walls of the hog house. In cold climates this construction with a layer of sheeting and building paper between should be used. Ship-lap makes a very desirable covering for the inside of the house. Clay blocks make a very good wall, and are cheap. No doubt they Will COme into more gen- Fi =- 27 °- A , sable-roof hog house made ° of concrete blocks. eral use. Concrete walls are very desirable, and, where gravel and sand can be secured cheaply, are much to be preferred over less durable construc- tion. The Roof. The usual method of constructing the roof is to lay shingles or prepared roofing over sheathing in the usual way. When nearly flat roofs are used, as with the half- monitor types, prepared roofing is preferable. Partitions. Partitions should be 3j^ feet high. Solid partitions are advised by a few, as they keep the hogs separate ; but open partitions intercept less light and when sows see one another and the attendant they give little trouble from interference or fright. Doors and troughs should be arranged for convenience. The front partitions may be arranged to .swing over the troughs for handy cleaning and feeding. Metal partitions, made of a metal frame with woven wire fencing across, have not generally proven satisfactory. As usually made they are not stiff enough, and generally give trouble from bending out of shape. If made heavy, metal partitions are quite expensive. 424 AGRICULTURAL ENGINEERING QUESTIONS 1. What are the essentials of a good hog house? 2. Where should a hog house be located? 3. Describe two types of hog houses. 4. Give the principal advantages and disadvantages of each type. 5. What is a good size of farrowing pen? 6. Describe the following types of individual hog houses: the A-shaped, the shed-roof house, and the gable-roof house. 7. Describe the arrangement of windows in the half-monitor and gable-roof hog houses. 8. Explain how a skylight may be used effectively to light a hog house. 9. Describe the construction of the foundation, the floor, the walls, and the roof of a large hog house. 10. Discuss the construction and arrangement of partitions in a large hog house. CHAPTER LXVI POULTRY HOUSES Location. Poultry houses should be located on well- drained, porous soil. Surface drainage is important, and, if necessary, it is always possible to modify the surface by grading. A gentle slope to the south or the southeast is best. A good windbreak is necessary, but there should be sufficient air drainage. Poultry houses should not be made a part of, or located near, other farm buildings which may furnish a harbor for vermin that will prey upon the young fowls. Poultry houses may be quite close to the dwelling house, as in many instances the women of the farm have the care of the poultry. Dimensions. Modern poultry houses are usually built on the unit system, that is, in sections for each flock of 25 to 100 birds. There has been much development of late years in regard to the amount of air and sunlight admitted to the poultry house; in fact, some houses are now built with one side entirely open to the weather. The poultry house is sel- dom built wider than 12 feet, although wider buildings may be more economical as far as space obtained for material used in construction is concerned. The unit or section is usually 16 feet long. Space for Each Fowl. The space for each fowl is usually based on the area of floor surface rather than upon the cubical space. Four to six square feet is usually allowed for each fowl. The breed of the fowl, the range or size of the lot, the climate, and the size of the house are factors to be taken into account in deciding upon the amount of space for each fowl. 426 AGRICULTURAL ENGINEERING Small birds require less space, and the wider the range the less the space required. More space is needed if close con- finement is necessary on account of the weather; and if the flock is large each individual bird will have more freedom, m >f b * m t—2-o'Cerien » Plan Fig. 271. Plan of an A-shaped colony poultry house. (la. Exp. Sta. Bui. 132.) requiring less space per fowl. In some instances the floor space per fowl has been reduced to 2 x /2 square feet. It is a good rule to allow at least one cubic foot for each pound of live weight, or from 5 to 20 cubic feet per fowl. If enough height be provided for convenience in caring for the fowls, there will be plenty of volume. The Foundation. Poultry houses are of light con- struction and do not need elaborate or expensive founda- tions. Colony houses are built upon skids. It is well that the foundation of the nonportable houses be so constructed as to exclude rats. If clay blocks or other masonry con- struction be used, the foundation should extend below the frost line, to overcome the damage which might be done by FARM STRUCTURES 427 Front Elevation Front elevation of the house shown in Fig. 270. the heaving action of the frost. Masonry foundations are to be preferred on account of their greater durability. Walls. Any wall construction will be satisfactory so long as it will prevent drafts, retain the heat, prevent the condensation of moisture, and furnish a smooth surface which may be entirely freed from mites and other vermin. The following wall construc- tions are generally used : 1. Walls made of a single thickness of boards, matched or battened. Usually this construction is too cold for anything except southern climates. Building paper may be used on the inside of the boards to make the walls air-tight. 2. Double wall, same as above, except ceiled on the inside. For general use this construction is fairly warm but gives trouble from condensation of moisture. 3. Same wall as No. 2, but the space between the outside and inside boards is filled with hay or other insulating mate- rial. This is a very warm wall and gives little trouble from condensation. 4. Same as No. 3, except the inside sheeting is replaced with lath and hard plaster. The latter gives a finish which may be thoroughly disinfected when desired. 5. Masonry walls of concrete or clay building blocks. Concrete makes a good wall for a poultry house if made double. 428 AGRICULTURAL ENGINEERING 6. Small houses may be covered with prepared roofing laid over plain or matched lumber. Such construction is warm and air-tight. Floors. The cheapest floor for the poultry house is the earth floor, but it is likely to give trouble from dampness, and is dusty and difficult to keep clean. Clay should be used for the floor in preference to a loam soil. The earth surface may be removed occasionally, or the entire floor may be Perspective °r nests Fig. 273. Detail of nests for house shown in Fig 270. replaced with new earth. Another objection to the earth floor is that it is not vermin-proof. Board floors are quite expensive, not very desirable, and, to be warm, should be made double, with a layer of tar paper between the two layers of boards. Board floors are likely to form a harbor for rats. Cement floors are the most durable, the easiest to clean and disinfect, and are quite reasonable in cost. The objec- FARM STRUCTURES 429 tions to the cement floor are that they are very hard, cold, and quite likely to be damp. A liberal use of litter on the floor will overcome the first two objections. If placed on Well- Note.— Roosts ond Droppinq board be removed separately F%^ Rodsts »» Drdpfinb Board Fig. 274. Detail of roosts and dropping board. drained soil or on a porous foundation of cinders or gravel the floors ought not to give any trouble from dampness. Light sidewalk construction makes a satisfactory floor. Roofs. The roofs of poultry houses are made in various shapes, the principal object sought with any style is to secure plenty of windows with the least material. Although gable Perspective Framing Fig. 275. The frame of the house of Figs. 271 to 274. 430 AGRICULTURAL ENGINEERING roofs and half-monitor roofs are used to quite an extent, the shed-roof house, extending east and west with the slope of the roof to the north, is the prevailing type in this country. This type of roof gives an abundance of room for windows or muslin curtains. Where the house is made portable and is to be moved among trees, as would be the case in an Fig. 2iG. A photograph of the house shown in Figs. 271 and orchard, the combination roof may be used to advantage. This roof is like the shed roof, except a small portion is made to slope to the front, reducing the height of the building. Shingles may be used for the roof if the pitch is one-third or greater, and building paper is used under the shingles to make the roof air-tight. FARM STRUCTURES 431 Prepared roofing is very satisfactory for the roofs of poul- try houses, as it is air-tight, and when a good quality is used its durability will compare favorably with shingles. m 1= ! HZfl g - e: 4' .Studs 2-o - Centers ¥ 5 2*4 Roo^s Horse ^«|j ^ Roosts and Center Horse can be removed separately 'from th<> rVo D - pna board (NlOTE. End doors may be omitted if only one section of +he house is built. Plan Fig. 277. Plan of a farm poultry house with shed roof. (la. Exp. Sta. Bui. 132.) Windows. It is recommended by good authority that there should be at least 1 square foot of window glass well placed for each 16 square feet of floor space. The tendency in the development of poultry-house construction has been toward large glass or curtain fronts facing the south to let in the warmth during the day. The muslin curtains are mounted on frames which permit them to be opened and closed with ease. The openings for the curtains are covered with wire cloth or netting. 432 AGRICULTURAL ENGINEERING Doors. The doors for poultry houses are found to be the most convenient when hung on double-acting hinges. Doors so hung can be pushed open even if the hands are filled. Partitions. The partitions in continuous houses may be made of boards or plaster. It is quite a common oractice to use poultry netting for the upper part, but the lower part should always be made solid. Ventilation. Although flues or the King system (see chapter on ventilation) could be used to ventilate poultry Front Elevation -io'i -j^-4'Tile Fig. 278. Front elevation accompanying Fig. 277. houses, ventilation is generally secured by means of cloth fronts. For other farm buildings this means of ventilation has not proven satisfactory, but has been successful with poultry houses. Types. Poultry houses are constructed after two plans: (1) the colony system, consisting of isolated houses usually made portable for each flock; and (2) the continuous system, consisting of several adjoining units with pens for each. FARM STRUCTURES 433 Development, however, has brought out the following three popular types of houses: 1. The scratching-shed house is built in sections con- taining two rooms, one for feeding and scratching and the other for roosting and laying. 2. The curtain-front house, commonly called the Maine Station House. In this construction the roosting and laying room is in the rear of the scratching pen. 3. The fresh air or Tolman house. In this house the front and parts of the sides are open. No more protection Fig. 279. Details of the nests of the house shown in Figs. 277, 278. is secured for the fowl at night than during the day. This is essentially a colony house, but may also be constructed on the continuous plan. Nests. The size of the nests will depend on the size and breed of the birds, but should be 12x12 inches and 5 inches 434 AGRICULTURAL ENGINEERING deep for Leghorns or small fowls, and 14x14x8 inches for Cochins or Brahmas. Special Features. The poultry house should be wind proof and free from drafts. A curtain placed in front of the roosts will keep fowls warm in severe weather. The nests should be dark, for hens lay better in such nests, and the egg-eating habit is prevented. Due protection against mites and lice should be provided by making the house smooth and free from cracks on the inside. The nests, roosts, and droppings board should be remov- able for cleaning or spraying. The roosts should be about 234 feet from the floors, with all bars at the same height, as ladder roosts cause the birds to Perspective OF Roosts Fig. 2S0. Details of roosts of the house shown in Figs. 277 to 279. crowd to the top bar. The roosts are best when about 2 inches wide and only the corners rounded, and rigid enough to prevent one bird from disturbing others on the same bar. The bars ought to be placed 12 to 14 inches apart and 8 to 12 inches allowed for each bird. FARM STRUCTURES 435 QUESTIONS 1. Where should the poultry house be located? 2. How much space should be allowed for each fowl? 3. Describe suitable foundations and walls for poultry houses. 4. Discuss the construction of the poultry house floor. 5. What are the common types of roofs for poultry houses? 6. What materials may be used to good advantage in the con- struction of the roof? 7. Discuss the management of windows for poultry houses. 8. What are the curtain fronts for poultry houses? 9. Discuss the arrangement and construction of doors and parti- tions. 10. What is the usual provision for ventilation in the poultry house? 11. Describe the usual types of poultry houses. 12. What should be the size of the nests? 13. Discuss some of the special features of poultry-house construc- tion. CHAPTER LXVII DAIRY BARNS Essentials. The essentials of a good dairy barn may be enumerated as follows: 1. Warmth. Dairy cows cannot be expected to produce well unless comfortably housed. Cows protected from cold require less feed. 2. Sanitation. Since dairy products are used for human food and since there is nothing that is so easily contaminated with filth and disease as milk, the sanitation of dairy barns is perhaps the most important factor in their construction. 3. Ventilation. In order that cows shall produce well and remain healthy, they must be provided with plenty of fresh air. 4. Light. As explained in another chapter, adequate natural lighting is necessary to cope with disease. 5. Dryness. Barns must be dry; damp barns breed disease. Ample drainage must be provided. 6. Convenience in handling stock and feed must be con- sidered. 7. Box Stalls. The barn must have provision for box stalls, also pens for young stock and the bull, unless other provision is made. 8. Storage room of sufficient capacity to suit conditions must be provided for feed. Types of Barns. Dairy barns may be classified according to the method of handling the cows and also according to the height of the building. The open feed room type of dairy barn is arranged to let the cows run loose, and has but FARM STRUCTURES 437 a few stalls for use in milking. This style is well adapted to certified milk production, as each cow may be groomed before milking. An objection to this type of barn is that the cows cannot be fed individually. It saves time in feeding, how- ever, and the cost of construction is low. The barn with stalls is the more common type. In com- parison with the other system it may be said to be economical of room and that it enables each cow to be fed her proper ration. The cows are under better control, and it is easier to save and handle the litter. Shed or single-story construction has the advantage of being well lighted and easily kept clean, but is not economical Fig. 281. Floor plan of a modern dairy barn. in construction. This type usually has a monitor roof, with a row of windows on each side. A loft or storage floor sup- plies economical space and enables the barn to be kept warm more easily. In this case all light must come from side win- dows. The Foundation. The foundation for a dairy barn should extend below frost and should be on firm soil. The width of footing may vary from 12 to 16 inches. An 8-inch founda- tion wall of concrete or hard-burned brick is sufficiently strong; a wall of rubble work should be wider. Sills should be 12 to 15 inches above the floor. 438 AGRICULTURAL ENGINEERING Walls. It is essential to have a wall dry and warm, and smooth on the inside. Drop siding is often used on the out- side of the studding and smooth ceiling on the inside. In mild climates a single wall is satisfactory, but in northern climates a double wall must be used. A cement-plastered wall on the inside is very suitable from a sanitary standpoint. In extreme cold localities the walls may be stuffed with hay or shavings. A monolithic, or solid, concrete wall is damp, but a hollow wall is very satisfactory. These walls are made with about a 4-inch air space between a 5-inch outer wall and a 3-inch inner wall, reinforced and tied together with iron or steel headers or ties. Windows. Windows should be placed to give maximum light; about 1 square foot of glass to 20 to 25 feet of floor space is adequate. Space Required. A common rule is to allow 1 cubic foot of space for each pound of live weight housed. For the av- erage dairy cow 500 to 700 cubic feet is sufficient when there is proper ventilation. The stalls should be from 36 to 42 inches wide, for average conditions. The ceiling is usually 8 feet in the clear. Floors. Cement floors are the most satisfactory, but are condemned because they are cold. But if dry and pro- vided with sufficient bedding, they should be satisfactory in every way. They are by far the most sanitary. Board floors may be used but are not durable and are more difficult to clean. No woodwork should be imbedded in cement floors. Cork and wood blocks are used to some extent but have not passed beyond the experimental stage. The Roof. Shingles or a high grade of prepared roofing may be used. Size of Gutter. The gutter is usually 14 or 16 inches wide and 4 to 10 inches deep. The bottom may be level, FARM STRUCTURES 439 crosswise, or sloping to one side. The latter is objectionable, as cows sometimes slip in a gutter with a sloping bottom. The gutter should have a slope lengthwise of 1/16 to 1/10 inch per foot for drainage. Facing of Cows. Opinions differ as to the advantages of facing cows in or out when two rows of stalls are used. Stalls that face in are convenient in feeding, and the cows do not face the light, which is said to be injurious to their eyes. Ven- tilation may also be more effective. The opposite system Fig. 2S2. Interior of a modern dairy barn. gives advantages in removing the litter and in milking and handling the cows. Mangers. The mangers for dairy barns are made of plank, concrete, or sheet steel. Concrete mangers are more sanitary and durable than wooden mangers, but are more expensive. They should be made continuous, with a drain at one end for cleaning. The back side of the manger must be from 4 to 6 inches high, enabling the cows to lie down. Mangers are usually about 3 feet in width over all. Box mangers should be made removable, to facilitate cleaning. 440 AGRICULTURAL ENGINEERING Patented mangers may be purchased which rest on the floor, having no bottoms, and which may be raised out of the way for cleaning. Ventilation. (See Chapter LXXXIV on this subject.) Stalls. Stalls for dairy cattle vary in length from 4 to 5 feet, and in width from 3 to 4 feet. The requirements of the different breeds in this respect vary widely. The length refers to the distance from the manger to the gutter. A stall 4 feet 6 inches long and 3 feet 6 inches wide is suitable for average conditions. Wooden stalls or partitions are being rapidly displaced by metal ones. The modern stall, as shown in Fig. 282, is made entirely of pipe or tubing, with bolted connections. The size of pipe or tubing generally used has an outside diameter of 1^ or 1% inches. Fig. 283. Cross section through stalls in a modern dairy barn. Cow Ties. One quite satisfactory method of securing cows in the stalls is by means of a strap around the neck snapped to a ring in a chain extending between the posts of the stall. This device permits of a reasonable amount of freedom for the cow. . The stanchion, however, is the device more generally used, and the later models of swinging stanchions leave little to be desired. The old-style fixed stanchions were too rigid, but the present forms are supported at the top and bottom by short lengths of chain, giving greater freedom of movement to the cow. FARM STRUCTURES 441 QUESTIONS 1. What are the essential features of a good type of dairy barn? 2. Describe the various types of dairy barns with reference to methods of handling the dairy cows and the height of the building. 3. Discuss the construction of the foundation for a dairy barn. 4. In like manner discuss the construction of the walls and the roof. 5. How determine the proper amount of window surface? 6. Discuss the construction of the floor. 7. How much space is required per cow? 8. What should be the size of the gutter? 9. Discuss the relative merits of having two rows of stalls face in or out. 10. What should be the size of the manger? Discuss its construc- tion. 11. What should be the dimensions of a stall for a dairy cow? 12. Describe the construction of suitable stalls. 13. Describe the chain cow tie. 14. What advantages does the swinging stanchion offer as a cow tie? 15. Discuss the construction of mangers for the dairy barn. CHAPTER LXVIII HORSE BARNS Some important features of horse-barn construction are: 1. The location should be prominent, as it is one of the most used of farm buildings. 2. Good surface and underdrainage are necessary. 3. The barn should be well lighted. 4. Provision for sufficient hay and feed must be con- sidered. 5. Vehicle storage is often needed. -6V ' *— S — ika 1 *-?-*-^^ 4-*-S^— f^-taii Fig. 2 84. Floor plan of a general farm barn. Space. Each horse will require from 700 to 1000 cubic feet of air space. The barn must be 20 feet wide for a single row of stalls and 30 feet for a double row. The foundation should be of stone, concrete, or hard- burned brick, and should extend below frost with sufficient width of footing. Piers of stone and concrete are often used. Ceiling. The ceiling of horse barns should be at least 8 feet in the clear. FARM STRUCTURES 443 Walls. The walls of horse barns need not be as warm as those for dairy barns. The single wall is often considered sufficient except in the most severe climates. Floors. The floor may be of cement or plank, but clay is often preferred for the front half of the stall, at least. A shallow, covered gutter 2 inches deep is a good thing when proper drainage can be provided. Facing. The horses may be faced in or out, and the same conditions apply that were mentioned under dairy barns. The feed alley should be at least 3 feet wide, and a width of 4 feet is desirable. A drive-way should be 8 feet wide for a wagon or manure spreader, and 12 feet wide for a hayrack. Stalls. Horse stalls are usually made of two-inch lumber. Pipe partitions have been used to a very limited extent. The ac- companying sketch shows a very satisfactory type cf stall where simplicity of construction is desired. Single stalls for horses vary much in width, all the way from 3 feet 8 inches to 6 feet. Five feet is considered a good width. Double stalls are usually made 8 feet wide. A good length of stall is 9 feet 6 inches, measured from the front of the manger to the back of the partition. Box stalls vary from 8x10 feet for a small stall to 10x12 feet for one of liberal size. Stall partitions should be about 6 feet high. Mangers, etc. Mangers are usually 2 feet wide and 3 feet 6 inches high. The floor of the manger should be about 15 inches above the floor. A general farm barn with gambrel roof. 444 AGRICULTURAL ENGINEERING Water troughs should be provided at a convenient point. A harness room is essential in order to protect the leather from stable fumes. Hay carriers should be so installed as to enable the mow to be filled readily. Ventilation. (See Chapter LXXXIV.) 6 &4- Oection thru £x-6 Fig-. 286. Detail of construction of a horse stall. QUESTIONS 1. What are some desirable features in the horse barn? 2. How much space should be provided for each horse? 3. Discuss the construction of the horse barn with reference to foundation, ceiling, walls, and floor. 4. How wide should feed alleys be? 5. Discuss the construction of horse stalls. CHAPTER LXIX BARN FRAMING Roofs. Several types of roofs are used in barn construc- tion. The hip roof, which slopes from the four sides of the barn to a point, is sometimes used for small barns. The shed roof, which slopes only one way, is used for narrow barns. The gable roof slopes in two directions and has gables, from which it derives its name. Gable roofs are quite generally used for barns. The curb or gambrel roof is much like the gable roof, except each side of the roof has two pitches. This type of roof is quite generally used for barns, and, in addition to being quite rigid when properly constructed, it adds to the capacity of the haymow. The Braced or Full Frame. In this type of frame heavy timbers are used, which are mortised and pinned together. Many barn frames have been made after this style, but the cost of the lumber and the advantages of the plank frame have caused an almost complete discontinuance of this style of frame. When now used it is a modification of the old form. The Plank Frame with Purlines. In this type of barn no attempt is made to keep the haymow free from framework, and the long rafters are supported upon the purlines resting upon posts throughout the frame. It is possible to keep the mow free from framework directly under the hay carrier track, and when so constructed it should not be inconvenient. This type of a frame is not generally popular, but there can be no serious objection to having the posts support the rafters when they are properly placed. 446 AGRICULTURAL ENGINEERING A model Wing joist barn frame. Pig. 2SS. A model Shawver barn frame. FARM STRUCTURES 447 The Wing Joist Frame. The Wing joist frame is made entirely of 2-inch lumber. The frame consists of bents or sections placed at intervals of 10 to 16 feet. The wall posts usually have five pieces of 2-inch lumber below the mow, two of which are continuous, and extend to the plate on which the rafters rest. Girders running across the barn from post to post are usually made of three pieces of 2-inch lumber. A 8'*IO~Column_ ', from 5-Z''8s Fig. 289. A sketch of the Wing joist barn frame. diagonal brace is placed from the top of the post supporting the plate to an inside post to care for the thrust of the rafters. Vertical siding is usually nailed to girts on the outside of the posts. Plates for the rafters are made of two pieces of 2- inch lumber in the form of a box. Iron rods are sometimes used to brace the plates, but wooden braces are preferable, 448 AGRICULTURAL ENGINEERING owing to the fact that they are not only strong in tension but are stiff and make a more rigid structure. A curb roof is used, and the rafters, which are usually 2x6's are strengthened at the curb by braces of inch boards or 2- inch pieces cut to fit underneath. The rafters are usually placed two feet apart on the larger barns of this construction, i 11 W'rfSrW "^ 5-2-rs- 34 -O' Fig. 290. A sketch of the Shawver barn frame. and should have diagonal braces to make the frame more rigid. The Wing joist frame is not adapted to barns over 40 feet wide. The Shawver Barn Frame. The Shawver barn frame, as now constructed, consists of bents made up of 2-inch lum- ber and placed 8 to 16 feet apart, on which the wall and rafter FARM STRUCTURES 449 coverings are placed. The Shawver frame is quite thor- oughly braced in every way, as is shown by the accompanying- drawing. It is one of the standard forms of barn frames. Steel Frames. Steel frames are now manufactured for barns to a limited extent. The frame is made entirely of steel in the shop ready to set up. They are generally more expensive than the wooden frames. Round Barns. In some localities the round barn is very popular. In general, it has two serious objections: (1) It is quite difficult to light a large round barn efficiently, and (2) it is difficult to ar- range the barn so as to prevent a considerable waste of space. A lar- ger space can be enclosed, however, within the wall of the round barn than in any other type using the same amount of ma- terial. Generally the frame for the round barn consists of studding, spaced about two feet apart, on which wooden hoops of inch lumber bent to the circle are nailed. The roof is conical in form and is very rigid. 77 \^ I H Fig. 291. A sketch of a barn frame with posts and purlins. Most round barns have a double pitch to the roof, with the rafter cuts as for the Wing joist frame. QUESTIONS 1. Discuss the merits of shed, gable, and gambrel roofs for barns. 2. Describe the braced or full frame for a barn. 450 AGRICULTURAL ENGINEERING 3. Describe the construction of a plank-frame barn with purlines. 4. Describe the construction of the Wing joist frame. 5. Describe the construction of the Shawver plank frame. 6. What are the principal advantages and disadvantages of a steel barn frame? 7. What are the objections to a round barn, and its principal advantages? 8. Describe the usual method of framing a round barn. CHAPTER LXX THE FARMHOUSE The purposes of a farmhouse are: 1. To be a home, a meeting place of the family. 2. To afford protection. 3. To house the various goods and treasures of the family. 4. To provide a place for the administration of the farm. 5. To adorn the landscape. In brief, the farmhouse should represent comfort, con- venience, and economy. Location. Consideration should be given to the follow- ing features in the location of the farmhouse. The health- fulness of the location should be given first consideration. The site should provide water and air drainage, and on this account a hillside slope offers many advantages. A well should be within reasonable distance, if a supply of good water is not supplied by other means. The barn should not be too far away. A suitable place for a table garden should be near. If located too far from the road, the house will be lonely; if too near, privacy will be lost. Designing the Farmhouse. Each house must be designed to fit particular conditions and requirements. Plenty of time should be used in preparing the plan. It is best to con- sult a practical builder or architect. The preliminary draw- ings should be drawn to scale in order that the planning may be carried on more intelligently. Arrangements should be made for possible improvements. The Foundation. The foundation should be made of goo d, durable masonry and should extend below frost for about 452 AGRICULTURAL ENGINEERING 3^2 feet, under most conditions. A brick wall 8 inches thick is sufficient. Stone walls are usually made 12 to 18 inches thick, according to the difficulty of laying a wall of less thick- ness. A concrete wall 6 to 8 inches thick is satisfactory. A double wall is preferable because it is much drier. The footing of the wall should be 6 to 8 inches wider than the wall. The Cellar. The cellar wall should extend at least 2 feet above the ground line, to provide window space for adequate lighting. Great care should be taken to make the cellar wall as dry as possible. In some instances it is necessary to plaster the outside, making it air-tight, and to lay a drain tile line outside the footing. Often material can be saved by building the cellar under the entire house. Such con- struction is regarded as the most sanitary, if the cellar can be kept dry. If a furnace is to be installed, the ceiling should be suffi- ciently high to provide room for the installation of the warm air pipes. THE PLAN . The Dining Room. The dining room is often regarded as the center of the farmhouse, and is in most instances used as the living room. When so used it should be large enough to contain not only the dining table, but also a library table and a bookcase. The dining room should have plenty of light, and a southern or western exposure is preferable. The Kitchen. The kitchen of the farmhouse ought not to be too large, if it is not used as the laundry. Large kitchens are the cause of unnecessary work. It is best to arrange the kitchen with fixed cupboards and to provide a sink and a convenient location for the range. FARM STRUCTURES 453 The Pantry. Every modern house should have a pantry, which is most convenient when in connection with both the kitchen and the dining room. The Sleeping Rooms. The sleeping rooms may be as small as 10x10 feet, but 12x14 feet is preferable. All sleeping rooms should be provided with closets. The Staircase. The staircase should be wide and not too steep. Winding steps are to be avoided. The Bathroom. The bathroom may be as small as 6x8 feet, but 8x10 feet is regarded as a good size. It is most Fig. 292. First and second floor plans of a farmhouse. convenient for the installation of plumbing when located over the kitchen. The bathroom should have an outside window for ventilation and light. The Washroom. Although not usually provided, the farmhouse should have a room where the men of the farm 454 AGRICULTURAL ENGINEERING may hang their extra coats and stable clothes. This room should have lavatory facilities, enabling the men to wash before entering the dining room. The Laundry. Nothing is more useful in a well-designed farmhouse than a room equipped as a laundry. When adequate drainage can be secured, it is best located in the basement. QUESTIONS 1. What are the purposes of a farmhouse? 2. What are the requisites of a good location for a farmhouse? 3. What course should be followed in designing a farmhouse? 4. Discuss the construction of the foundation. 5. How should the cellar of a farmhouse be constructed? 6. Discuss the special features to be considered in the planning of the dining room. The kitchen. The pantry. The sleeping rooms. The bathroom. The washroom. The laundry room. CHAPTER LXXI CONSTRUCTING THE FARMHOUSE The Full Frame. The full frame corresponds to the full frame for barns, made of dimension stuff, mortised and pinned together, and in which the wall frames are raised as a unit. This framing began to be displaced by the balloon frame about 1850, and is now used only in a modified form. It resists fire better than the balloon frame, but may not be any more substantial. The Balloon Frame. The balloon frame is made of light timbers, usually 2 inches thick and of varying widths. The usual method of construction is to lay the sills, which may be either a box sill of two 2x8 timbers, or a 4x6 timber. The latter is halved in splicing at the angles and in the corners. In the case of the box sill, one piece is laid on the wall and the other on edge upon the first. The sills support the first- floor joists, and from them, also, the studs, generally 2x4's, are erected. The studs are made double at the corners and at each side of the openings for doors or windows. They are placed 16 or 12 inches o. c. (apart), the former being the usual spacing. The studs extend to a double plate of two 2x4 scantlings. They may be extended by a second piece placed end to end and spliced with boards nailed on each side. The joists for the second floor are supported by a girt or ribbon of lx4-inch boards let into the studding. The studding at each corner should have a lx6-inch brace notched in, or a diagonal brace made from a 2x4 fitted between the studs . The rafters for the attic are supported by the top plate and the joists. A common practice is to use a box sill, lay the rough 456 AGRICULTURAL ENGINEERING flooring, and place the studding on a bottom plate nailed to the flooring. To support the studding well, the rough floor- ing should be laid diagonally ; otherwise all the studding on one side will be attached to one board. It is very difficult to prevent a one-and-a-half story house from sagging, due to the thrust of the rafters on the plate, which cannot be held together. Bridging. Bridging consists of diagonal strips, usually 1x3 inches in cross section, nailed between the floor joists to Fig. 293. A concrete block house representing a good type for the farm. stiffen and strengthen them. Joists 8 to 16 feet long should be bridged once; those 18 to 24 feet long, twice. The floor should be leveled as the bridging is nailed fast. Two lOd nails should be used at each end of the bridging pieces. The studs should extend from sill to plate in interior walls the same as for outside walls, in order that shrinkage will be uniform. FARM STRUCTURES 457 Sheathing. It is advisable to put sheathing on diago- nally, as it then strengthens the frame very much, and the extra cost of wasted material and labor is not great. The wall sheathing is best when made of matched lumber. Siding. The siding generally used is lap siding or weather boarding. White pine is the wood generally used and is regarded as very satisfactory. Drop siding, or so-called patent siding, does not give a pleasing effect, although quite satisfactory in other respects. Stucco or plastered walls are very satisfactory when the plastering is on metal lath. Lathing. The lathing should be carefully done, insuring uniform spaces between the lath. The girder carrying the second floor joists should be set in far enough to enable the lath to be nailed on strips and permit the plaster to clinch around the lath. The direction of lathing should not be changed, as there is a greater tendency to crack the plaster when shrinkage occurs. An extra 2x4 should be used in each corner so that the lath can be securely nailed in place. The Roof. The greater the pitch of the roof the better, but a half pitch makes a good roof. Wooden shingles are generally used, those of cypress or red cedar being regarded as the best. One thousand shingles laid 4 inches to the weather should cover 100 square feet; but when laid 43^ inches to the weather shingles will make a good roof. There are 250 shingles in a bale, which is made 25 layers thick and 20 inches wide. Five shingles should make a thickness of two inches. In laying the shingles, joints should be broken twice, and plenty of nails should be used in nailing them on. Creosote and other stains act as a preservative, but painting is not advisable. Shingles may be dipped in oil with good results, for which about 23^ gallons of linseed oil are required per M. The Exterior Finish. The following suggestions in regard to the exterior finish may be useful. It should be plain, and 458 AGRICULTURAL ENGINEERING all filigree and turned work should be avoided, as it is not durable. The cornice should be broad in order to protect the walls. The use of a water table, with an edge under the siding, insures a dry wall. Due provision should be made above windows and doors for excluding water. Only the best paint should be used, and perhaps there is none better than pure white lead and linseed oil colored, when desired, with the proper tints. Plastering. Back -plastering is thought to be very bene- ficial in cold, wet climates, although not generally used. Back plastering may be either between the studding or on the studding, with the second layer of finishing plaster on lath nailed to furring strips. The latter is regarded as the better method, as there is a tendency for cracks to form from shrinkage in the former method. Metal corner beads should be used on all exposed plastered corners. The lime for lime plaster should be slacked at least 24 hours before adding hair. It should be then allowed to stand stacked up at least ten days before using. Lime mortar may be made by adding to each barrel of lime 3 barrels of sand and 1 to V/2 bushels of hair. Hard plaster should be mixed according to the directions furnished by the manufacturers. These plasters give a harder wall and better protection against moisture. The first coat of moisture is called the "scratch coat," the second the "brown coat," and the third the "white" or "skim" coat. Sometimes the third coat is omitted and the walls are left rough or given a "float" finish, which is tinted with a calcimine wash. The Woodwork. Dust lines should be eliminated as far as possible, and for this reason plain finish is desirable. The architraves or casings may be mitered or fitted with blocks at the corners; the latter does not show the effect of shrinkage as badly as the mitered corners. The block placed at the FARM STRUCTURES 459 bottom of the casing to doors is called the plinth. The fol- lowing are some additional suggestions: 1. Ample head room should be provided over stairs. 2. The sum of the rise and tread of steps should be about 1734 inches. 3. "Winders, " or triangular steps,* should be avoided. 4. A half post should be placed where the banister rail joins the wall. 5. Dimensions of windows are given by the number and size of lights. 6. All sash should be carefully balanced. A good grade of cotton cord is satisfactory. 7. The stop bead should be fastened with screws to per- mit of adjustment and the removal of sash. 8. Doors are made in three grades, A, B, and C. Those of standard size and dimensions are known as stock doors. Veneered doors are usually more satisfactory than solid ones. The Hardware. The butts, locks, knobs, and escutcheon plates should be of good quality. The usual grades of hard- ware are japanned iron, bronze plated, and solid bronze. Much can be added to the appearance of a room by using artistic, high-grade hardware. Loose pin, wrought-iron butts should be used, as they are stronger than cast-metal butts. Mortise locks are to be preferred over rim locks. Hinges should be of ample size and should permit the door to swing back against a stop on the wall. The Finishing Woodwork. All woodwork should be sand-papered with the grain before the application of any finishing material. Nails should be well set and the holes well filled with putty. Two coats of hard oil or varnish make the cheapest but the least desirable finish. The best finish is five or six coats of shellac rubbed down. A wood filler may be used before 460 AGRICULTURAL ENGINEERING the first coat. The final coat should be of the best grade of varnish. Floors are usually filled and varnished, or var- nished with shellac and waxed. Woodwork may be stained with water, oil, or spirit stains. Water stains may go deeper but do not preserve the wood as well as oil stains. Spirit stains are the most expensive and must be carefully applied, as any lapping shows badly. QUESTIONS 1. Describe the full frame for houses. 2. Describe the balloon frame for houses. 3. What is the objection to a one-and-a-half story house as far as framing is concerned? 4. Describe bridging and state its use. 5. When is it advisable to put sheathing on diagonally? 6. What are the relative merits of lap siding and drop siding? 7. What care should be taken in lathing a house? 8. Describe the construction and the materials used in building the roof. 9. What are some of the important features of the exterior finish of a farmhouse? 10. Explain what is meant by back plastering. 11. What care should be used in preparing plaster? 12. What does scratch coat, brown coat, and skim coat designate? 13. What is the composition of lime plaster? 14. What is a float finish to a plastered wall? 15. Discuss some important features of the woodwork. 16. What care should be used in selecting the hardware? 17. State how the woodwork may be finished. 18. What are the relative merits of the various kinds of wood stains? CHAPTER LXXII THE SILO The Location of the Silo. In locating a silo, the matter of convenience should be given first consideration. It should be in direct communication with the feed alley in the barn. A good location is some four to six feet from the barn and joined to the feed alley by a chute extending up the entire height of the silo. A door should close the passage-way between the barn and the silo; and if the space be made to accommodate the silage cart, it will not only make feeding- easier but will also provide a good place for storing the cart when not in use. Nearly all types of modern silos are best located outside of the barn. As a rule, the silo does not need the protection of a building, and the barn space may be more economically used for other purposes. Furthermore, an inside silo is inconvenient to fill, as it is difficult to deliver the fodder to the ensilage cutter unless large driveways are provided, which again are not economical. The odor of silage is thought objectionable by some; but when the silo is located outside of the building and connected with it only by a chute, this objection is overcome. The Size of the Silo. The modern silo is round. This shape will resist the bursting pressure of the silage to the best advantage and permit of a more perfect settling of the silage, which is very important. A round silo has two dimen- sions, diameter and height. The diameter or cross section of the silo should be determined by the size of the herd. From \ x /i to 2 inches of silage should be fed from the silo 462 AGRICULTURAL ENGINEERING each day, after the silo is opened, to keep the silage fresh. If a less amount is fed, a growth of mold is quite likely to start and travel downward as fast as, if not faster than, the rate of feeding. The proper height of the silo is readily determined by the length of the feeding season. It is an advantage, how- ever, to have a deep silo. First, it is ecomonical, as addi- tional volume is obtained without adding to the expense of foundation and roof. Secondly, the silage depends upon the exclusion of air for its preservation, and the extra weight of silage in a deep silo promotes settling and assists in this direction. Two silos of medium diameter are better than one large one, as there may be times when it is desired to feed the silage lightly. Capacity of silos, and the amount of silage that should be fed daily from each. Inside diameter Height Capacity, tons Acres of corn of 15 tons per acre Amount. to be fed daily, pounds 12 12 12 12 30 32 34 36 67 74 80 87 4.5 5.0 5.3 5.8 755 755 755 755 14 14 14 14 30 32 34 36 91 100 109 118 6.1 6.7 7.2 7.9 1030 1030 1030 1030 16 16 16 16 16 16 30 32 34 36 38 40 119 131 143 155 167 180 8.0 8.7 9.5 10.3 11.1 12.0 1340 1340 1340 1340 1340 1340 18 18 18 18 36 38 40 42 196 212 229 246 i 13.2 14.1 15.26 16.4 1700 1700 1700 1700 FARM STRUCTURES 463 The usual amount of silage fed per day to various classes of stock. Kind of stock Daily rations, pounds Beef cattle Wintering calves 8 months old 15 to 25 Wintering breeding cows 30 to 50 Fattening beef cattle, 18-22 months old First stage of fattening 20 to 30 Latter stage of fattening 12 to 20 Dairy cattle " 30 to 50 Sheep Wintering breeding sheep 3 to 5 Fattening lambs 2 to 3 Fattening sheep 3 to 4 The preceding tables— which give the capacity of some of the more common sizes of silos, the number of pounds of silage which must be removed daily to lower the surface an average of two inches, and an average ration for each of various kinds of farm stock — should provide sufficient information for deciding upon the size of silo to meet ordinary requirements. To explain the use of these tables, suppose silage is to be fed to 10 head of dairy cows, 8 head of calves, and 40 head of beef stock, for 200 days. The amount of silage required per day will be about as follows: 10 dairy cows, 40 lbs. each 400 lbs. 8 calves, 20 lbs. each 160 lbs. 40 beef cattle, 20 lbs. each 800 lbs. Total silage fed per day 1360 lbs. Referring to the first table, it will be found that a silo 16 feet in diameter will furnish 1340 pounds of silage when 2 inches is fed daily; hence 36 feet, or 216 times 2 inches, will be about the right height. Some allowance should be made for settling. The Essentials of a Silo. To preserve silage a silo must have impervious walls which will not permit air to enter or 464 AGRICULTURAL ENGINEERING moisture to leave. The wall must be strong and rigid enough to resist the bursting pressure of the silage, and sufficiently smooth on the inside to permit the silage to settle readily. In addition to these absolute essentials, there are many features which add to the value of a silo and which should be considered in its selection. Some of these features are as follows: 1. It is highly desirable that a silo be as durable and permanent as possible. All parts should be constructed of materials which will insure a long term of service. 2. The silo should require a minimum expenditure of labor and materials for maintenance. This refers to the adjustment of parts for shrinkage and expansion, repainting, and the substitution of new parts for those which have become decayed or otherwise useless. 3. The silo should have a wall which will prevent as far as possible the freezing of silage. 4. The silo should be arranged in such a manner as to be convenient for filling and for the removal of the silage. This refers directly to the construction of the doors. 5. In some cases it is desirable to have a silo which may be taken down and moved from one location to another. 6. A fire-proof silo may have the further advantage of serving as a fire wall. 7. A silo should be sightly and should add to the appear- ance of the farmstead. 8. It is an advantage to have a silo of simple construc- tion, which may be erected with the minimum of skilled labor, and in the construction of which there is little chance for expensive mistakes. 9. Lastly, the silo of the lowest cost per unit of capacity, giving due consideration to the other features of merit, is the most desirable. FARM STRUCTURES 465 If these essentials and desirable features are kept clearly in mind, they will assist in comparing the various types of silos now in general use. WOOD SILOS The Stave Silo. The commercial stave silo is in more extensive use today, the country over, than any other type. When properly made, the walls are air-and water-tight, smooth and rigid, insuring the preservation of the silage. The durability of the stave silo depends largely upon the kind and grade of the material used in its construction. Redwood, cypress, Oregon fir, tama- rack, and white and yel- low pine are the more common kinds of wood used, and their respective merits and durability rank about in the order given. The Plain Stave Silo. The stave silo made of plain dimension lumber, without being beveled or grooved, is not satisfactory. Such a silo is certainly cheap, but is very unstable, when the staves are matched, and as soon as there is a little shrinkage there is a tendency for the staves to fall from place into the silo, and then the whole structure collapses. Fig. 294. A good stave silo well anchored. The walls are not as tight as 466 AGRICULTURAL ENGINEERING Full-Length Stave Silos. Full-length staves are desirable, although more expensive. If spliced staves are used, the method of splicing should be carefully examined. The ends of the staves are fitted together by a U-shaped tongue and groove; but the more common method of splicing con- sists in inserting a steel spline about 1-16 inch thick in saw cuts in the ends of the staves to be spliced. The Foundation. The stave silo should be put upon a good foundation. The foundation wall need not be wide, 12 inches being a good width, but it is well that it extend below the frost line, or about 2% to 3^ feet. As the silo is likely to be partly full during the coldest weather, the frost will not be deep near the foundation. Any masonry construction may be used for the foundation, but concrete is especially, well adapted to the purpose. Use of the Pit. It is doubtful if a pit is advisable with a stave silo. The increased capacity so secured is economically obtained ; but there should not be a shoulder or bench inside of the staves, as this will prevent the free settling of the silage. If a pit is used to increase the capacity of the silo, and the foundation wall is made flush with the staves on the inside at the time of erection, it will be difficult to keep the silo on the foundation as shrinkage occurs. Anchoring and Guying. The stave silo is a light struc- ture and when empty is more or less at the mercy of the wind. To guard against any possible damage from this source, it should be carefully anchored to the foundation and guyed or braced in all directions. The anchors to the foundation should be at least four in number, and may be made of bars extending into the masonry and bolted to the staves above. The top of the silo should be carefully braced to any adjoin- ing buildings. The guy wires or cables should run in pairs to posts and buildings in opposite directions. These FARM STRUCTURES 467 guys are more effective when extending out some distance from the base of the silo. The importance of this anchoring and bracing is urged upon all. The Roof. Every silo should have a roof: (1) It adds to the appearance; (2) it strengthens and protects the staves; (3) it is a big factor in preventing freezing; (4) it makes the silo a pleasanter place in which to work. No attempt should be made to secure ventilation; in fact, an attempt should be made to retain the warm air in the silo as far as possible. Pre- pared roofing of good quality makes a durable silo roof. It is easily fitted to a conical form. The Doorway. All commercial silos at the present time have a continuous doorway, across which there are no obstruc- tions except the crossties. This type of doorway offers certain advantages in removing the silage, and is just as satisfactory in other respects as the individual doorway. In selecting a silo, it is well that an examination be made of the door-fasteners to see whether or not the door makes a per- fectly air-tight joint with the frame. The Minneapolis Silo. The Minneapolis silo, or so- called panel silo, is constructed of pieces of planks about 2 feet long, matched at the sides and beveled at the ends, set into vertical studding. The whole is then bound together by hoops, which require practically no adjustment, as there is little shrinkage lengthwise of the grain. Defective pieces in this silo may be replaced by cutting them out, driving down the pieces above, and inserting new ones at the top. This type of silo is very rigid and stable. MASONRY SILOS The Concrete Silo. Concrete is one of the best materials for silos. It is very important to make the concrete silo wall impervious to air and water. The more common method of 468 AGRICULTURAL ENGINEERING doing this is to treat the inside of the wall, as soon as the forms are removed, with a wash of pure cement and water reduced to the consistency of paint. This wash thoroughly seals the pores of the walls and prevents the loss of mois- ture and the admission of air. A coat of coal tar has been used with good results, and there are many patented compounds on the market which ought to be entirely satisfactory. In several cases where no attempt was made to seal the walls the juices of the silage apparently accomplished that result, after two or three fillings, but this should not be relied upon. Reinforcement. Another common mistake is the lack of reinforcement or the improper use of reinforcement. The bursting pressure of silage is considerable, about 11 pounds per square foot for each foot of depth, as an average; and this pressure must be fully cared for or the walls are sure to crack. A mixture of one part of cement, two of sand, and four of broken stone or screened gravel ought to make a good silo wall. If good natural gravel and sand are at hand, a mix- ture of one to five will be satisfactory. The Block Silo. There are two methods of using con- crete: (1) in the form of blocks, which are made and cured before being laid in the wall; (2) the monolithic wall, requir- ing the use of forms. The first method involves a large amount of labor in making and handling the blocks and lay- ing them in the silo wall. So much labor is involved that it is likely to be the most expensive item of the entire cost. The use of forms in the monolithic construction dispenses with a large part of the labor, but in turn offers some serious disadvantages. To obtain good, smooth walls, rather expensive forms must be made; and as the silo reaches some height, the forms are difficult to handle without expensive scaffolding and hoisting apparatus. FARM STRUCTURE 469 Monolithic Silos. The solid wall does not offer serious objections in permitting the freezing of the silage, especially if provided with a good, tight roof. The concrete silo blocks are nearly al- ways made to contain an air space, and double forms may be used in the mon- olithic construction, mak- ing a double wall. When air circulation is restricted in the dead-air space by horizontal partitions about every three feet of height, the double wall is perhaps the most satisfactory, as far as frost-proof qualities are concerned. The cost of a concrete silo will depend largely upon local conditions. The cost of sand, gravel, and labor are the deciding factors. Under usual conditions, the cost should not greatly exceed the cost of a first-class wood- en silo. No attempt will be made here to discuss the con- struction of forms. The Hollow Clay Block, or Iowa Silo. In general, this silo consists of a wall of vitrified clay building blocks reinforced with steel laid in the mortar joints. The roof is made of concrete, and the silo has a reinforced concrete door frame. Description of the Blocks. The blocks are hard-burned building blocks, and may now be had curved to the curvature of the silo wall, making a smoother wall on the inside. These o^S monolithic silo crete roof. 470 AGRICULTURAL ENGINEERING blocks are of the same material and have the same character- istics as brick; in fact, in certain localities they are called hollow brick. If these blocks are of good mate- rial and hard-burned they are very durable. The 4x8xl2-inch block has proven to be a very satisfactory size. Larger blocks are too large to handle with one hand, and smaller ones require more labor in laying. These blocks are laid on edge, making a four-inch wall. The Cement Wash. If curved blocks are used and care is used in point- ing and filling the mortar joints, the wall will be suf- Fig. 296. The Iowa silo made of hollow ficieiltly SmOOth On the Ul- vitrified Cay building blocks or tile. ^ ^ om j t t he plastering. To seal the mortar joints and make the whole impervious, a cement wash should be applied before the mortar becomes hardened. Reinforcement. The entire bursting pressure of the silage should be carried by steel wire imbedded in the mortar joints. Number 3 wire has been found to be a very satis- factory size. It is small enough not to interfere with the laying of the blocks, and fewer strands are required than of the smaller sizes. This wire should be unannealed, and may be straightened to the curvature of the silo by drawing it through a piece of pipe bent to the proper angle. FARM STRUCTURES 471 297. The wall of the Iowa silo. The Doorframe. The doorframe is continuous with the crossties, which are at least 42 inches apart. The jambs are simply reinforced concrete beams. The crossties contain reinforced bars of equal strength to the horizontal reinforce- ment in the wall proper, and extend back to each side into the open space in the blocks, to obtain a good grip upon the wall. The blocks containing the bars are completely filled with concrete. The bars across the doorway are covered either by blocks filled with concrete or by concrete alone. The Foundation. The foundation for the Iowa silo may be of any good masonry construction. It is im- portant that the footings be placed below the frost line. Concrete and hard-burned blocks have been used with equal success. A 16-inch footing and a 6- to 8-inch wall are all that is required. The space inside of the wall may be economic- ally added to the capacity of the silo. The extra expense involved is simply that of throwing out the earth within the foundation walls. Floors. Although a floor is not absolutely necessary, it adds much to the convenience of removing and cleaning up the silage at the finish. Four inches of concrete will make an excellent floor. Paving blocks or sidewalk blocks have been used successfully. A few floors have been made by laying the hollow blocks flat and plastering with cement on top. 472 AGRICULTURAL ENGINEERING The Roof. The roof of the Iowa silo is constructed of concrete, making this part as durable and lasting as the rest of the silo. The cornice is made of blocks laid flat-wise, and the center is made of two and one-half to three inches of concrete placed upon a conical form. The conical shape is very desirable for a concrete roof, as nearly all of the reinforcement may be confined in the base of the cone. If thoroughly reinforced at this point, there is little opportunity for failure. A window must be provided in the roof for filling the silo. QUESTIONS 1. Where should the silo be located? 2. What are the factors that determine its diameter and height? 3. How does the capacity of a silo vary with its diameter? How does the amount of material in the walls vary with the diameter? 4. How much silage should be fed from the surface each day? 5. What are the essentials of a good silo? 6. Discuss the construction of the stave silo. 7. Upon what does the durability of the stave silo depend? 8. What are the merits of the plain-stave silo? 9. How are silo staves spliced? 10. Discuss the construction of the silo foundation. 11. Can a silo pit be used to increase the capacity of a stave silo? 12. Describe how a stave silo should be anchored and guyed. 13. Describe two types of doorways for silos. 14. Describe the construction of the Minneapolis or panel silo. 15. What is necessary to make a satisfactory silo wall of concrete? 16. How should the walls be reinforced? 17 What kind of mixture should be used in preparing the concrete? 18. What are the advantages and disadvantages of the cement- block silo? 19. Describe the monolithic concrete silo. 20. Describe the hollow clay block or Iowa silo. 21. What are the desirable features of clay blocks for silos? 22. How may the wall be made impervious? 23. How can the clay-block silo be carefully reinforced? 24. Describe the construction of the doorframe, the foundation, the floor, and the roof of the Iowa silo. CHAPTER LXXIII THE IMPLEMENT HOUSE AND THE SHOP The Value of an Implement House. It is not economical to have the machinery stored in the general barn or in any- expensive building. The implement house or shed need only provide protection from the weather. Barns do not furnish good storage on account of the dust which must necessarily be about and because of the inconvenience. The Location. The best location for the implement house is that which makes it a central feature of the farmstead group. A location about half-way between the house and barn and a little to one side of a direct line between the two buildings seems to be the most generally desirable. The implement house in this connection is thought of as provid- ing storage for the farm wagon and other vehicles used upon the farm. Its location should be such that it will be con- venient to hitch to a vehicle or implement upon coming from the barn with a team and enable the driver to pass as directly as possible to the field or to town without extra travel. The Size. The size of the house will depend on the number of implements to be stored. It is not best, however, to have the building too wide, as it will be inconvenient to remove certain implements on account of those stored in front, which arrangement will be necessary to utilize all of the space in a wide building. In preparing to build an implement shed, it would be well to determine the floor space required for each implement and then plan on having a certain place reserved for each. This arrangement will save much time in handling the implements. 474 AGRICULTURAL ENGINEERING The Foundation. The foundation need not be heavy; a 6-inch concrete wall will be ample if it be widened to 8 to 12 inches for the footing. Piers are very satisfactory for a frame building. If the walls of the house are to be of masonry construction, the foundation should extend below the frost line. The Floor. A dry earth floor is customary in the imple- ment house. A wood or concrete floor in the carriage or Fig. 298. A convenient open-front implement house. automobile room would be desirable, but not a necessity. Concrete is best, as boards or planks are likely to provide a harbor for rats and other vermin. The Walls. The walls need only provide protection from the sun, moisture, and wind. Either drop or matched siding or plain boards with battens may be used. The plain boards, as usually erected, make a tighter wall after they have been in use for a time, and they last longer. Concrete makes a very good wall for an implement house and is not unduly expensive if the wall is not made too thick. A four-inch wall, is sufficient if placed upon a good foundation, and, if the wall be long, it may be stiffened by an occasional pilaster. In like manner a four-inch brick wall will be found to be quite FARM STRUCTURES 475 satisfactory. Hollow clay building blocks, when such mate- rial of good quality can be readily obtained, make a very desirable wall for the implement house. Blocks are much cheaper than brick and more wall can be laid in a given time. One advantage of the masonry walls is that they are more nearly dust-proof than a single-board wall, and the imple- ments they protect will present a better appearance at all times. This feature is of little advantage except in the care of the buggies or carriages. If a good, tight wall be provided, it will not be necessary to cover the vehicles with a cloth, as is practiced by many who take pride in the appearance of their turnouts. The Roof. The roof can well be made of an assortment of materials. Roofing boards with battens make a good, cheap roof for a narrow building, especially those with the roof sloping one way only. A shingle roof, of at least one- third pitch and of a good quality of cedar or cypress shingles, is quite satisfactory, but is not nearly as dust-proof as some of the other forms of construction. A layer of building paper over the sheathing, as commonly used in house construc- tion, would improve it in this respect. Prepared roofing makes a very desirable roof for an implement house, as it is perfectly tight and when a good quality is used its durability will compare favorably with shingles. Care should be taken to make the walls tight between the roof and the plate, where it is desired to have a dust-proof building. The Framework. The framing of an implement house is not difficult. If a gable roof is used, 2x4 rafters placed two feet on center will be sufficient for a building 16 feet wide, if given at least one-third pitch. If the house has a shed roof, 2x4 rafters will be sufficient for a 12-foot span with a one- third pitch. A wider building should have 2x6 rafters, if the building is to retain its shape. If the house is to have a sec- 476 AGRICULTURAL ENGINEERING ond floor, and the joists do not support the plate and prevent the thrust of the rafters from spreading the building, there should be several diagonal braces from the plate to the joist. The implement house may be built with one side open. This is a convenient arrangement, but does not keep out the dust; and the chickens of the farm, if not confined, will find the machinery a very satisfactory roosting place, much to the detriment of the machinery. If large doors are provided, it L 48-0' -pQty&rs&lGs. °cff9!yz. A°?/y^?x ^■Corfcrof-e )sa// ,-'*- i J°1/j Cor7cfo/o p/'ors S4~-S4~ base. -' ■ 4"-6 support exfe/?as ft/// /ength ofb/c/g. Fig. 299. A cross section of the house shown in Fig. 298. will not be inconvenient to store the various machines; in fact, one entire side may be made up of doors hung on a double track, half of them being on the outside track and the other half on the inside track. This arrangement permits of the doors being opened at any point. It is often an advantage to have a second floor, to accom- modate the light implements, such as the cultivator, stalk cutter, corn planter, etc. The implements may be drawn up on a runway by means of a horse and a rope and pulley. FARM STRUCTURES 477 THE FARM SHOP Utility. From an extensive investigation on the life and care of farm machinery in Colorado, it is reported * that 71.36 per cent of the farm machinery on farms not having shops needed repairs, while only 59.25 per cent on farms having shops needed repairs. These facts are taken by the writer of the bulletin to mean that the farm shop has a "real value beyond the occasional emergency job." It is well-nigh impossible to maintain the efficiency of the farm equipment without a liberally equipped shop. It is not so much a matter of saving a few dollars by doing repair jobs, as it is a matter of getting the work done. The Location. The location of the farm shop should be similar to that described for the implement house; indeed it may be made a part of or an addition to the implement house, as its usefulness is largely directed toward the farm machinery. If a forge is installed, due thought should be taken of danger from fire. The location may also be selected with reference to any small stationary engine or other source of power the farm may have, so that the same power may be available for tools in the shop. The Size. The farm shop may be built large enough to house a wagon or similar implement, or it may be just large enough to contain a bench and tools and furnish the minimum amount of working room. A shop 16 by 20 feet will be needed to accommodate large machines. On the other hand, a shop 8 by 10 feet will house a bench, a forge, and an anvil, and may be considered the minimum size for practical pur- poses. Construction. The house should afford comfortable quarters for work during cold weather. If made wind- *Bulletin No. 167, Colorado Agricultural Experiment Station. 478 AGRICULTURAL ENGINEERING proof, a stove may be put in. If a forge be installed, it and the anvil should be placed on earth, concrete, or some other kind of fire-proof floor. The exterior of the shop should be made to conform to the style of the other buildings about the place. In buying the equipment, care should be exercised to get good, standard tools of known merit. QUESTIONS i. Why have a separate implement house on the farm? 2. Discuss the best location for an implement house. 3. How may the size of the implement house be determined? 4. Discuss the construction of the foundation, the floor, the walls and the roof of the implement house. 5. Describe how the frame of an implement house may be con- structed. 6. To what use may the second floor of an implement house be put? 7. Why is a repair shop needed on a farm? 8. Where should the farm shop be located? 9. What are satisfactory dimensions for a farm shop? 10. Discuss the construction of a farm shop. LIST OF REFERENCES FOR FARM STRUCTURES Building Trades Handbook. Farm Buildings. Radford's Practical Barn Plans. Barn Plans and Outbuildings. The Farmstead, I. P. Roberts. Tuthill's Architectural Drawing. Architectural Drawing, C. F. Edminster. Practical Suggestions for Farm Buildings, U. S. Dept. of Agri., Farmers' Bui. 126. College Farm Buildings, Mich. Agri. Exp. Sta., Bui. 250. Circular No. 15, Division of Forestry, U. S. Dept. of Agri. Architects' and Builders' Pocket Book, F. E. Kidder. Mechanics of Materials, Church. Materials of Construction, J. B. Johnson. FARM STRUCTURES 479 Farm Poultry House, Bui. 132, Iowa Agr. Exp. Sta. Building Poultry Houses, Cornell Bui. 274. Poultry House Construction and Yarding, Mich. Bui. 266. Poultry House Construction, Wisconsin Bui. 215. Poultry Architecture, George B. Fisk. Location and Construction of Hog Houses, 111. Agr. Exp. Sta., Bui. 109. Hog Houses, U. S. Dept. of Agr., Farmers' Bui. 438. Portable Hog Houses, Wis. Agr. Exp. Sta., Bui. 153. Suggestions for the Improvement of Dairy Barns, 111. Agr. Exp. Sta., Cir. 95. Economy of the Round Dairy Barn, 111. Agr. Exp. Sta., Bui. 143. Sanitary Cow Stalls, Wis. Agr. Exp. Sta., Bui. 185. Plank Frame Barn Construction, John L. Shawver. Hodgson's Low Cost American Homes. Modern Silo Construction, la. Agr. Exp. Sta., Bui. 100. The Iowa Silo, la. Agr. Exp. Sta., Bui. 117. Concrete Silos, Universal Portland Cement Co. Specifications, International Correspondence School Text. Ventilation, F. H. King. King System of Ventilation, Wis. Agr. Exp. Sta., Bui. 164. PART EIGHT— FARM SANITATION CHAPTER LXXIV THE FARM WATER SUPPLY The subject of farm water supply easily divides itself into the following heads, each of which will be discussed in turn: 1. The source of supply. 2. The quantity required. 3. The pumping plant. 4. The distribution system. 5. The storage tank or reservoirs. The Source of Water Supply. The first requisite of a suitable source of water supply is that it shall furnish pure water. It is fully realized at the present time that one of the most important places where the health of the family is to be guarded is the water supply, for so many diseases are traceable to polluted water. It is not so essential that water be pure chemically as that it be free from all germs which may cause trouble in the human system. Water may con- tain a considerable percentage of certain mineral salts and yet be quite healthful. On the other hand, water may be quite free from all salts or mineral matter, be clear, cool, and spark- ling, and still be filled with deadly typhoid or other disease germs. Wells. The well is the most common source of water supply for the farm. Wells are divided primarily into two classes, with reference to their depth, as shallow and deep wells. The shallow well refers to those either dug by hand FARM SANITATION 481 or bored with a common well auger. These wells are usually of considerable diameter in order that there may be a reser- voir for a quantity of water within the well itself. The shallow well is the one most easily contaminated and is the one which should be most carefully protected. It is best that the well be located at some distance from any leaching cess-pool, privy, or manure heaps. It is difficult to state just how far away, as some soils are much more open than others and the impurities will travel a correspondingly greater distance Fig-. 300. A sketch showing hew the water of a shallow well may be- come contaminated from manure yards and cess-pools. (Kansas Exp. Sta. Bui. 143.) through them. Then, again, drainage lines become quite thoroughly established in the soil in certain directions; and if the well and a source of contamination should happen to be placed in one of these seepage lines, the contamination would take place at a much greater distance than otherwise. It is best, however, that the well, especially a surface well, be located at least 100 feet from any disease-laden filth. Much can be accomplished in providing protection against contamination from the surface: ,(1) The curb or well wall 482 AGRICULTURAL ENGINEERING should be made water-tight for some distance below the sur- face; (2) the well should have a good, tight platform or cover; and (3) the surface of the ground should be raised about the well so that all surface drainage will be away from the well. Surface wells are the cheapest of all wells. The cost per foot, with curb, varies from 50c for a 12-inch hole, to over $2 for a well four feet across and walled with loose stone. A good platform cemented over will cost about $10. It might be mentioned here that concrete makes an ideal pump platform and will last indefinitely. One slab can be made loose to furnish access to the well. Deep wells are usually either driven or drilled. A driven well is made by attaching a sand point to a casing, usually 134 inches in diameter, and simply driving it into the ground until the point reaches a water-bearing stratum of gravel or sand. The sand point is made of perforated brass over an iron frame, through which the water will readily pass into the casing. The pump cylinder is made a part of the casing, and valves are set at proper places by expanding rubber rings to fit the casing. Driven wells never extend through a rock stratum. Drilled wells are made by operating a drill inside a casing which sinks as the drill provides the way. The mud and chips of stone are removed by pumping a stream of water through the drill and out through the casing. If the casing is of small diameter, about two inches, with the cylinder a part of it, it is called a tubular well. The usual diameters for drilled wells are 6 and 8 inches. These diameters permit the pump cylinder and piping to be entirely independent of the well casing. The usual cost of tubular wells, with casing, is $1 to $1.50 per foot. Drilled wells range in cost up to $6 per foot for an 8-inch well drilled in granite rock. Deep wells are rightly considered a better source of water supply than shallow wells, yet they are by no means entirely FARM SANITATION 483 free from contamination. Occasionally drainage lines are so thoroughly established in the soil and through fissures in the rock that the water of the deep wells may be contami- nated from the surface. Springs are sometimes used as a source of water supply. It is best that the spring discharge at as high an elevation as possible in order that there may not be many habitations above it. When springs furnish water from some depth, the Fig. 301. An improved spring showing how it may be protected from surface water. water is quite sure to be free from all organic matter. In considering a spring as a source of water supply, it should be definitely known that a sufficient amount of water will be furnished throughout the year. Most springs are irregular in their discharge and at times furnish little or no water. The ideal location for a spring is at an elevation above the farmstead, to which the water may be led in pipes and perhaps allowed to flow constantly, the surplus being wasted. If the spring is below the farmstead, yet high enough to permit a 484 AGRICULTURAL ENGINEERING waste to still lower levels, and if the flow is ample a hydraulic ram or pumping plant can be used. Brooks or running streams form another source of water supply, but should be carefully considered before using. A close inspection should be made to determine whether or not the stream is in any danger of pollution by surface washing from manured fields or house and farm yards. River water is quite apt to be turbid during the flood season. Streams flowing through uninhabited or uncultivated upland will fur- nish water of the most desirable character. Lakes usually furnish water that is clear and potable, ow- ing to the fact that the water is purified by coming to rest and allowing the impurities to settle. Often, in settled commu- nities, where the practice is not forbidden by law, the banks of lakes are used as a dumping ground for all sorts of refuse. Such practice prevents the use of the water for human composition. Drinking water obtained from a stream or lake should be filtered. A box filled with sand and gravel or charcoal through which the water must pass is the most common type of filter in use. The Quantity Required. Care must be taken, in selecting a water supply, to determine that the quantity of water available will be sufficient not only for all present needs but also for any increased demand that may be foreseen. The daily requirements must also be taken into account when planning a reservoir or storage tank. The greater part of the water consumed on the farm is required by the live stock for drinking purposes and by the household. The house requirements depend largely on whether or not plumbing fixtures are installed. The amount consumed per day by each of the various farm animals is about as follows: A horse, 7 gallons; a cow, 6 gallons; a FARM SANITATION 485 hog, 3 gallons; and a sheep, less than 3 gallons. Dairy cows giving milk require additional water in proportion to the amount of milk given. Where sanitary plumbing is installed, about 20 gallons of water per day will be consumed for each person, large or small, and for all purposes, including the laundry. QUESTIONS 1. Into what divisions or heads may the subject of farm water supply be divided? 2. What are the principal sources of water supply on the farm? 3. Explain how surface and deep wells are dug or drilled and curbed or cased. 4. Describe how the well should be protected from contamination. 5. When may springs, running water, and lakes be used as a source of water supply? 6. How may the daily consumption of water b^ estimated? 7. Estimate the amount of water required on the home farm. CHAPTER LXXV THE PUMPING PLANT The pumping plant for a farm water supply consists of some form of motor and a pump. Although many pumps are still operated by hand, a modern water system can scarcely be considered complete without a motor, for the simple reason that man caimot compete with motors in the production of power. A specific instance is on record where a gasoline engine pumped the water for a dairy herd at a cost of one cent per day for gasoline; whereas two hours of hand labor, worth at least 20 cents per hour, were formerly required. It is a waste of money to pump by hand if a large quantity of water is required daily. The forms of motors now in use for pump- ing purposes are the windmill, the gasoline engine, and, in a few instances, the hot-air engine and the water wheel. Sources of Power. A windmill is better suited by far for the pumping of water than for any other purpose. The power of a windmill is quite limited; yet an average pump requires little power. Furthermore, the power is quite irreg- ular, but if a storage reservoir is used this undesirable feature is easily overcome. As discussed in a previous lesson, the cost of windmill power consists of the interest on the invest- ment, and the depreciation and maintenance. The gasoline engine is well adapted to the pumping of water. As has been stated, the average pump requires very little power, and the gasoline engine has the advantage over other heat motors in that it is very economical in small units. A series of tests made a few years ago at the Iowa State Col- lege indicated that 20 barrels of water could be pumped FARM SANITATION 487 against a head of 100 feet, or, in other words, lifted that dis- tance, for every day in the year, at a cost of less than five dollars for gasoline. Again, the gasoline engine does not need constant attention. If anything goes wrong, the engine will likely stop without doing damage. A float or other safety device may be connected with the igniting system or fuel supply in such a way as to stop the engine when a certain height of water in the supply tank or a certain pressure has been attained. Hot-air engines have little to commend them other than their reliability and safety. Solid fuel of almost any kind, as well as oil and gas, may be used. They are not economical of fuel, but where the fuel is cheap they may be oper- ated at a reasonable expense. Water wheels can be used only in rare instances, and will not be dis- cussed for this reason. There are, no doubt, many places where they may be used to advantage. Fis 302. A good type of three-way or underground The pump is as important a ™- a ™- r fX P cyiCefto throw the windmill out of gear when a certain pressure has been reached. part of the pumping plant as the motor. Pump troubles and repairs are always very annoying, and a pump of good constructio n and properly installed is always a good investment. The amount of power required to operate a pump is small, as will be shown by the following table : 488 AGRICULTURAL ENGINEERING Pump tests. No. test Kind of cylinder 03 M o w Lift Gals, per min. H. P. used Hydrau- lic H. P. Effi- ciency percent 2 2 Yi ", brass lined 8 50 5.81 .195 .0732 57.0 3 2}4", brass lined 8 100 5.33 .255 .1343 52.5 8 3 ", brass body S 50 8.01 .21 .1019 48.4 9 3 ", brass body 8 100 7.8 .395 .1965 49.6 26 4", plain iron S 50 10.0 .52 .126 21.2 17 4", plain iron 8 100 10.3 .75 .259 34.7 Important Features of a Pump. In selecting a pump, the service to be required of it should always be kept in mind. • If the water is only to be lifted from a shallow well and delivered into a pail or tank under the spout, any common lift pump may be used. A lift pump is one in which no provision is made for forcing or lifting the water higher than the pump spout. Force pumps have the pump rod packed, making it water-tight. One of the most important parts of a pump is the cylinder, of which there are three common grades on the market; viz., plain iron, iron with brass lining, and brass-body cylinders. The first is the cheapest, but is the least durable, as iron easily corrodes. Brass-lined cylinders are quite satisfactory, in that the iron supports and protects the brass, which is a soft metal. Brass-body cylinders are used where corrosion will be unusually rapid and where space is limited. Often, in drilled wells of small diameter, brass-body cylinders with the caps screwed inside of the barrel instead of on the outside are installed, thus permitting the use of a cylinder of rela- tively large diameter. Brass-body cylinders will not stand severe service. When dented, they are almost past repair, and the screwing of the caps to the thin barrel is difficult, be- cause little material is provided for the threads. Porcelain- FARM SANITATION 4S9 lined cylinders are used where the water contains elements that corrode iron and brass. Plungers are constructed to suit the lift under which they are to work. If the lift has but a few feet, one plunger leather which expands out toward the cylinder walls, making a water-tight fit, will be sufficient; but if the well is deep or the water is to be lifted against pressure, as many as four leathers will be found best. Fig. 303. Some common types of pump cylinders. 1 is of plain cast iron, 2 is galvanized, 3 is porcelain lined, 4 and 5 are brass lined, and 6 is an all-brass cylinder. The valves are another important part of a pump. They should be designed to resist wear and to require the minimum of attention. There are at least four types of valves used in farm pumps. The hinge valve, made with a metal weight on a leather disk and attached at one side, is used where the lift is not great. It is a simple valve and the cheapest, but is not well suited for high pressures. Poppet valves are those which lift directly from the seat, and are made with one or three prongs to guide the valve to its seat. These valves are the easiest to repair. Ball valves are used 490 AGRICULTURAL ENGINEERING where the water is likely to contain sand, as the seat of the ball valve is usually quite narrow and the sand is not given an opportunity to lodge upon it. The Stock. The part of the pump visible above the plat- form is known as the stock, and is made in a variety of styles. The simplest form is the lift pump, which, as a hand pump, was formerly made with wooden stocks, but now cast iron is generally used. The next simplest is the force pump, made after the plan of the common lift pump, with provision to pre- vent leakage about the pump rod. Where the water is to be pumped into a storage tank and the pump is in a more or less exposed location, a three-way pump may be used. It provides a valve that enables the water to be pumped out of the spout, or delivered through an underground pipe to the storage tank, or drawn from the tank through the spout. In cold climates a pump should be protected against freez- ing by surrounding the valves with a frost-proof well pit and providing for the drainage of the pump stock. If a com- pressed air system of water storage is installed, a special pump must be provided which will pump a little air with the water; or a separate air pump must be used. QUESTIONS 1. Is the pumping of water by hand ever economical? 2. What are the principal sources of power for pumping water? 3. Discuss the relative merits of the gasoline engine, the windmill, and the hot-air engine, for pumping water. 4. Describe the difference between a lift pump and a force pump. 5. What are the relative merits of the different kinds of pump cylinders? Pump valves? 6. Describe the three-way pump and its use. 7. How should a pump be protected from freezing? CHAPTER LXXVI DISTRIBUTING AND STORING WATER Water Pipe. After a consideration of the source of sup- ply for a farm water system, the quantity of water required, and the pumping plant, the next thing to be considered is the distributing system or piping by which the water is conveyed to points where needed and to the reservoir for storage. For farm water systems, wrought-iron or steel pipe with screwed joints is universally used. Cast-iron pipe with leaded joints is used for pipes four inches or larger in diameter, but pipes this large are seldom required in connection with farm sys- tems. Wrought-iron or steel pipes placed underground should always be galvanized or coated with asphalt to pro- tect them from rust. They are commonly galvanized. Sizes of Pipe. The two sizes of pipe in general use are three-fourths and one inch. In rare instances half-inch pipe may be used, but the flow of water through this size pipe is very slow, especially if a long length is used. The friction between the water and the walls of the pipe counteracts the pressure which causes the water to flow. The following table, taken from the Cyclopedia of American Agriculture, indicates how great the friction is with small pipe. Referring to the table it is seen that if a pump is deliv- ering four gallons per minute through a length of 3^-mch pipe 500 feet long, it must do so against a friction head or pressure of 270 feet of water. This would be impractical. Although the table does not include %-inch pipe, the loss of pressure due to friction would lie between the values given for %- and 1-inch pipe. The average farm pump will discharge about 492 AGRICULTURAL ENGINEERING 5 gallons per minute, which would require the use of pipe at least 1 inch in diameter or larger for mains, and the smaller sizes should only be used for branches. In many cases the pump is overloaded by using pipe of insufficient size. Flow of water in pipes. Flow in gallons per minute Head in feet lost by friction in each 100 foot of length l^-inch pipe. 1-inch pipe. 0.5 1.0 2.0 4.0 10.0 4 7 17 54 224 .03 .07 1.6 5.3 9.3 Piping Systems. There are two general types of under- ground piping systems on farms. The first of these is known as the " ramified " system, which consists of a main laid in the shortest possible line from the water supply to the farthest hydrant, with branches extending out on either side like branches of a tree. The one objection to this arrangement is that the water in the branches is dead unless constantly in use. There is, however, a saving in the cost of pipe, as smaller sizes may be used for the branches. The second type is known as the "circulatory " system, in which the main pipe passes to all hydrants and the extreme ends are connected, if possible. With this system the water does not stagnate in any part. In planning the distributing system, it is best to provide large mains if fire protection is desired. Valves should be put in various parts so that a disturbance in one part will not interfere with the use of the rest of the system. Often it can be arranged to have the fresh water, as pumped, pass through the house, thus providing drinking water. FARM SANITATION 493 Water Storage. The size of the storage tank and reser- voir will depend primarily on the kind of power used for pumping. It is customary to provide in storage a supply to last five days when the pumping is done by a windmill; and when a gasoline engine is used, the storage capacity may be reduced to a two-days' supply. The two general methods of storing water are by the use of the elevated tank and the pressure tank. The first of these depends upon gravity to force the flow of water, and the second uses compressed air. Towers and Tanks. The ideal location for an elevated water reservoir is upon some natural eminence. If the emi- nence is high enough to justify it, the reservoir may be built beneath the surface like a cis- tern, thus insuring that the water will be kept cool. If there is no natural means of securing elevation, the tank must be placed upon a tower or in a building. The height of the tower will depend upon the height of the buildings to which the water is to be delivered and upon the pressure desired. The tower may be made of steel, wood, or masonry. Masonry tanks are best, but often the cost is prohibitive. A tank on a tower is exposed more or less to the weather and will give trouble from freezing. This is especially true of steel tanks. Wooden tanks are preferred over steel for out- ■■- — tf 1 A n8 ^ Fig. 304. An Iowa silo with a masonry water supply tank on top. 494 AGRICULTURAL ENGINEERING side locations, as they are easier to erect and are cheaper. Cypress is considered one of the best woods for tank construc- tion, and may be expected to last 15 to 20 years. Tanks are sometimes placed in or on buildings, but great care should be taken to determine whether or not the building is sufficiently strong for the purpose. Water in quantity is very heavy: 300 gallons will weigh 2500 pounds, to which must be added the weight of the tank. Tanks placed in residences have often caused settling of the framework under- neath and consequent cracking of the plastering. In barns they can be supported to better advantage. Cement or concrete towers and tanks are coming into use and, when properly built and reinforced, there is no reason why they should not be economical. The masonry silo provides what is seemingly a good loca- tion for a water tank for a farm water supply. The tanks themselves may be built of masonry if properly reinforced, and plastered with cement plaster on the inside. The bottom of the tank can be easily constructed of concrete, if built in a conical form and reinforced to prevent cracking at the base. The Air-Pressure System. The pressure tank, or pneu- matic system, consists of an air-tight tank, a force pump, Pig. 305. An air pressure or pneumatic water supply system. FARM SANITATION 495 and suitable piping. As water is forced in at the bottom of this tank, the air within is compressed, thus driving the water from the tank to any part of the system. As the effective capacity of the tank may be increased by having an initial pressure of air within it, and as the water con- tinually absorbs a part of the air, an air pump or a pump to supply the air with the water must be provided. As the water is thoroughly protected by being tightly inclosed, the tank may be placed where a freezing tempera- ture is not reached. The cellar is the usual location. It may, however, be buried in the ground, which has the advan- tage that the water is kept at quite a uniform temperature throughout the entire year. The air pressure tank for a water supply of small capacity is very economical in first cost. Where the storage capacity is large, however, the cost is so great as to be almost prohibitive. A ten-barrel tank with a water storage capacity of six barrels will cost about $60, and larger tanks a correspondingly greater amount. A more recent water- supply system is known as the Perry pneumatic water-supply system. It consists in a power-driven air compressor, a storage tank for the air under pressure, and an air- driven water pump which pumps the water as required, maintaining a pressure upon the entire system. There is no storage of the water at all, Outer ce>.s//7. wifh screw ce>.p .r^s^:. T~7 ■Su pply Pipe 4. below frost lira Course Or£>vel A satisfactory method of install- ing exposed hydrants. 496 AGRICULTURAL ENGINEERING other than that contained in the pipes. Definite information is not at hand concerning the cost or the success of this system. One distinct advantage of it is that water maybe pumped from as many supplies as there are pumps. Thus one pump may supply well water for drinking purposes, and another cistern water for the bath and laundry. QUESTIONS 1. What kind of pipe may be used in the distribution system, and what are the merits of each? 2. What are the sizes of pipe generally used for the farm water- supply system? 3. Explain how the loss of friction may be serious with small pipes. 4. Describe the ramified and circulatory systems of water piping. 5. What provision may be made for fire protection, for repair, and or cool drinking water in the water supply system? 6. In what way does the amount of water storage vary with the source of power? 7. Describe the two general systems of storing water. 8. Discuss the construction of elevated water supply tanks. 9. What are the objections to an exposed water supply tank? 10. What care should be taken when the supply tank is placed in a building? 11. Why does a masonry silo make a good tower for a water supply tank? 12. Describe the air pressure or pneumatic system of water supply. 13. What are the advantages of this system and the main objection to it? 14. Describe the Perry system. 15. What is the principal advantage of this system? CHAPTER LXXVII PLUMBING FOR THE COUNTRY HOUSE Modern conveniences for the country home are usually understood to include sanitary plumbing fixtures for the bathroom and for caring for the wastes of the household. The use of such fixtures is dependent upon an adequate water supply, a subject which has been discussed in the preceding chapters. There is nothing which will do as much toward relieving the housewife of hard and disagreeable labor as the plumbing. It not only provides additional comfort and con- venience to the extent that when once used it is considered indispensable, but it also guards the health of all members of the household. Opinions differ widely in regard to the details of construc- tion and design of sanitary plumbing. In all cases care must be used that unnecessary expense is not incurred in securing something which does not represent quality. As a rule the most simple fixtures are the most satisfactory. All parts of the fixtures, such as traps and overflows, should be so placed as to permit of ready inspection. Plumbing Fixtures. In installing plumbing fixtures, con- solidation should be kept in mind. The usual fixtures installed in a country home are a sink and hot water appli- ances in the kitchen, and a bathtub, closet and lavatory in the bedroom. If the bathroom can be placed above or adjoining the kitchen the installation of the fixtures will be much sim- plified and much piping saved. The number of fixtures which may be installed will depend largely upon whether or not the house is to have furnace heat. If the house is to be 498 AGRICULTURAL ENGINEERING heated with stoves, the bathroom can best be arranged to adjoin the kitchen, and the heat therefrom ought to prevent the freezing of the water in the pipes. For this reason the pipes should be protected as far as possible from the cold. It is not best, how- ever, to place them in the wall, as exposed pipes are decidedly more convenient to repair. One very satis- factory method of caring for the pipes is to provide a conduit with a removable cover, which may be panel- ed in such a way as not to detract from the appear- ance of the room. All of the fixtures requiring drainage should be clus- tered about the soil pipe which should extend from the cellar up through the building and out through the roof for ventilation. This soil pipe is univer- sally made of four-inch cast-iron pipe with fittings inserted at proper places to receive the drainage from the various fixtures. It is best that a clean-out plug be provided at the bottom. At a slight additional cost, hot water may be provided. All that is required in addition is a hot water or range tank Fig. 307. A plumbing system for a two-story house. The vent pipe may be omitted with safety in country resi- dences. (Mo. Eng. Exp. Sta. Bui.) FARM SANITATION 499 and a water front for the kitchen range or furnace, and the necessary piping. The range tank is galvanized and usually holds from 30 to 60 gallons. The kitchen sink is one of the fixtures which is well-nigh indispensable. The cast-iron sink, porcelain lined and with a roll rim and a back piece, is the most convenient for clean- ing. The porcelain-lined sink is just as serviceable, if not more so, than the solid porcelain, and is much cheaper. It is very difficult to keep a plain iron sink clean, and the advan- tages of the porcelain-lined will justify its purchase. A very satisfactory size for a kitchen sink is 22 by 36 inches, and it should not be smaller than 20 by 30 inches. Though opinions differ, 32 inches is an average satisfactory height. One side may be conveniently arranged to receive the dishes as they are washed, permitting them to drain. Bathroom Fixtures. The bathroom ordinarily contains three fixtures; namely, a bathtub, a lavatory, and a water closet. Of recent years these fixtures have been greatly im- proved and cheapened in cost until a good grade is within the reach of all. A serviceable bathtub is one of cast iron, porce- lain lined but with a wide roll at the top. Like the kitchen sink it should not have any woodwork connected with it. The best tubs have all of the piping, including the drains and overflow, exposed. The standard width for bathtubs is 30 inches, and they may be had in any length from 4 to 6 feet. The lavatory should be either solid porcelain or porcelain- enameled cast iron. To avoid cracks in which dirt may accumulate, the back should be made solid with the bowl. The water closet in general use is of solid white earthen- ware with siphon action. The cleaning jet should discharge from the rim of the closet and should clean thoroughly. Two kinds of flush tanks are in general use, the "low down" and the "high." The first does not make as much noise when 500 AGRICULTURAL ENGINEERING flushed as the second but generally u?e? more water. The water is discharged from the second wlon considerable force, and for that reason is preferred by some. Back Vents. In nearly all cities all fixtures are required by law to have vents from the traps to prevent the water which closes the pipe and prevents the entrance of foul gases into the room from being siphoned over into the sewer. This system of piping is shown in the accompanying figure; it intro- duces considerable extra expense. In country houses there is doubtless little danger in omitting this extra piping. There will be little difficulty in installing plumbing in a house not built especially for the purpose, providing there is room for it. There is some inconvenience in putting the pipes in place, but in most cases they can be left in exposed locations, which is some advantage. The plumbing referred to and of the quality suggested will cost less than $200 almost anywhere in the Middle West; in fact, the average cost should not exceed $150. QUESTIONS 1. What are some of the general considerations involved in the installation of plumbing? 2. How may plumbing be arranged in houses without furnace heat? 3. How secure convenience in cleaning and inspection? 4. What are the usual fixtures required? 5. Discuss the merits of various grades of sinks. 6. What should be avoided in the selection of a lavatory? 7. Discuss the different types of water closets. 8. What is meant by back venting? 9. How much should the plumbing in an average farmhouse cost? CHAPTER LXXVIII THE SEPTIC TANK FOR FARM SEWAGE DISPOSAL Modern plumbing fixtures for the farmhouse introduce a new problem, the disposal of the sewage. Present-day ideas concerning sanitation have made the privy and the cesspool less tolerable than formerly. The modern sewage disposal plant, if it is to fill its purpose to the greatest extent, should not only prevent accumulation of sewage to harbor disease and contaminate the water supply, but should also provide for the saving of fertilizing material which otherwise would be wasted. Disposal of Sewage into Rivers. If a large stream of water be near, the sewage may be discharged into it in a manner similar to that followed by the large cities. The organic material contained in the sewage when exposed to the light and air as it passes off down the river is rapidly purified by bacterial action. Rivers as a means of disposing of the sewage from farmhouses are rarely available and will not be discussed further. The Cesspool. While the cesspool has been the most common method of disposing of sewage in isolated places, it has but few features to commend it and should not be used if there is the least danger of its spreading disease. As usually constructed the cesspool consists of a cistern in the ground, with an open wall, usually of brick, through which seepage takes place. In some open soils this seepage is rapid, and no difficulty is experienced from the cesspool overflowing at times. In dense, retentive soils, the solid matter of the sew- age closes the porous walls to the extent that the liquids do 502 AGRICULTURAL ENGINEERING not sweep away fast enough. If there is much grease in the sewage it is apt to become hardened over the surface of the walls, making them water-tight. To overcome this difficulty common lye has been used to cut the grease, with good success. All cesspools should be arranged with a manhole, which will permit the settlings or solid matter which collects in the bottom to be removed at regular intervals, perhaps once a year. Many cesspools that have been in use for years are entirely satisfactory as far as observations go. The success of these is undoubtedly due to the purifying bacterial action which the sewage undergoes in the tank. At best, however, the cesspool is a dangerous means of disposing of sewage, and new installations should be of more improved design. Often the contamination of the water supply is effected at an un- dreamed-of distance, resulting in typhoid fever, dysentery, and other complaints. Principles of Sewage Disposal. The principle involved in the purification of sewage in the modern disposal plant, regardless of whether it be for city or private use, is largely that of destroying the suspended matter in the water by bacterial action. Outside of this, some results are brought about by settling, thus caring for a part of the suspended material. When the sewage from a farmhouse, consisting of the wash water from kitchen and dairy and the discharge from plumb- ing fixtures, is drained into a dark reservoir and not disturbed for a time, rapid bacterial action takes place. The bacteria which work in a tank of this sort do not need light or air to live. The action is simply this: the bacteria feed upon the organic matter of the sewage and thereby partially destroy it; in addition, a partof this solid matter, or sludge, as it is called, is liquified. FARM SANITATION 503 The reservoir provided for this purification by bacterial action is known as the septic tank. To secure the best results, this septic tank should be designed to exclude light and air and to bring the sewage to rest and hold it so for a time. The purification of the sewage, however, is not completed in the septic tank. To complete the process, means must be provided to permit another class of bacteria to act upon Ouf/ef Fig. 30S. A general view of a septic tank arranged to be connected with an underground irrigation or filter system without a siphon. (After Stewart.) the sewage. These must have air and light or they cannot live. To supply the proper conditions for this second bac- terial action, two plans are followed : the first is to provide a filter bed of coarse material, usually gravel, over which the sewage from the septic tank is discharged at intervals; and the second is to provide a shallow tile system from which per- colation will take place. These tile are usually placed within ten to twelve inches of the surface, and, if the soil is retentive, a second and deeper system is laid to carry away the purified sewage. In some places this filter system of drain tile is used 504 AGRICULTURAL ENGINEERING as a means of subirrigation, furnishing the growing plants on the surface with moisture and fertility. It is to be noted that the discharge into the filter system should be intermittent, in order that the bacteria at work shall not be drowned. Another plan of filtering which is used to some extent is to allow the discharge to trickle down through a bed of sand, which is placed over a perforated cover, to a second tank in which the water level is maintained several inches below. The dripping of the sewage through the air corresponds quite Fig. •SecS/osr on A3 309. Section of a septic tank made entirely of concrete. a siphon and a filter bed of sand and gravel. closely to the sprinkling system of sewage disposal which is used to some extent in city plants. Size of Septic Tank. The septic tank should be suffi- ciently large to hold the entire discharge for about one day, in which case the best bacterial action will be obtained. Another rule tried out more or less by practice is to provide 20 gallons' capacity for each person in the household. There will be a settlement amounting to several pailfuls in the septic tank each year, and provision must be made for its removal. Construction of the Septic Tank. Concrete is the best material for the septic tank. The tile line to the tank from the house should be of vitrified bell-mouthed tile with cemented joints. FARM SANITATION 505 Fig. 308 is a general view of a septic tank which has been built for as little as $18.65. It has a plank top, and the only means of cleaning it out would be to uncover the earth and remove the planks. Fig. 309 is a more expensive plant, with a filter bed attached. The filter bed complete will cost by it- self about $20. The best results can be secured with a tank provided with a siphon. Fig. 310 shows a plan for laying the tile system to filter the discharge from the septic tank. It is remarkable how thoroughly sewage can be purified by an efficient plant. Often the effluent or final discharge from the filter bed will compare in purity with the best well water. Fig. 310. A plan of filtering the discharge tank. tile system foi from a septic QUESTIONS 1. How is sewage purified that is discharged into a river? 2. What are the objections to a cesspool as a means of disposing of sewage? 3. Discuss the construction of the cesspool. 4. How is sewage purified in a septic tank? 5. How can complete purification of the sewage be obtained? 6. Why is it best to have the sewage applied intermittently to the filter bed or irrigation tile? 7. Discuss the construction of the septic tank. 8. Estimate the cost of a sewage disposal plant for a household of ten people. CHAPTER LXXIX THE NATURAL LIGHTING OF FARM BUILDINGS Development. If a comparison be made between the farm buildings of twenty-five years ago and those which are entitled to be called modern, it would be found that one of the principal differences lies in the natural lighting, or the amount of window surface provided. This change is due largely to a more general recognition of the value of light as a sanitary agent. Purpose of Natural Lighting. The natural lighting of farm buildings has a three-fold purpose: (1) The principal purpose, to make the buildings more sanitary by destroying disease germs; (2) to provide a more convenient and pleasant place for the attendants to care for the animals; and (3) to provide more pleasant and comfortable quarters for the animals to feed and live in. As stated, the principal reason for providing adequate natural light for farm buildings is to secure sanitary quarters for the animals. Direct sunlight is far more powerful and destructive to disease germs than diffused or reflected light, and for this reason as much direct sunlight as possible should be provided. Usually but a short time, a few hours, is required to kill germs by direct sunlight. In regard to the value of diffuse light for destroying germs, Dr. Weinzirl, an eminent bacteriologist, is quoted in King's book on Ventilation as follows: "The shortest time in which diffuse light in a room killed the bacillus of tuber- culosis was less than a day, and the longest time was less than a week; generally, three or four days of exposure killed the or- ganisms. Some pus-producing bacteria required a week's FARM SANITATION 507 time to kill them, while some intestinal bacteria were killed in a few hours. It was also found that bacteria are killed more quickly in moist air than in dry, contrary to general belief. The diffuse light as found in our dwellings is, there- fore, a hygienic factor of great importance, and where direct sunlight is not available it should be carefully provided for." It is believed that the above quotation represents a clear, authoritative statement of the value of diffuse sunlight in producing sanitary quarters. Location of Windows. In locating the windows, great care should be taken that sun- light will be admitted in such a way as to allow the direct beams of light to sweep the entire floor. The angle of incidence of the sun's rays, or the distance of the sun above the horizon, for latitude 42° north varies from 70° the 22nd of June to 26° the 21st of Dec- ember. For other latitudes the angle of incidence is different. At the spring and fall equinoxes, which take place March 21 and Sept- ember 21, and for 42° N. the angle is 48°. Sunlight is more useful in the winter time than in the summer, and care should be taken to make use of the winter sun rather than the summer sun. For practical purposes it can be assumed that the most desirable sunlight enters the windows at an angle of 45°. Fig. 311. A sketch showing how the angle of incidence of the sun's rays varies throughout the year. This is at latitude 42° N. 508 AGRICULTURAL ENGINEERING Fij Design of Windows. The window casings should be designed to intercept as little of the direct sunlight as possible. Stone or concrete walls of considerable thickness should be ^ beveled on the inside so as to let in the full width of the beam of sunshine passing through the glass. For this reason windows that are long vertically are more de- sirable and more effi- cient than those which are wide but low. In the latter instance the casings and wall cut off a large proportionof the direct light admitted. Again, wide, over-hang- ing eaves cut off much direct sunshine from the windows located directly below. Size of Windows. No definite rules can be given for the amount of window surface to provide in barns and other farm buildings, owing to the fact that the efficiency of the windows depends so much on their location. It is good practice, how- ever, to provide one square foot of glass for every 20 to 25 square feet of floor surface. Judgment must be used in this connection, varying the amount with the location and shape of the windows. Dairy barns are generally provided with a larger window area than horse barns. There is a tendency to go to the extreme in lighting dairy barns. Many barns have been built during recent years with entirely too much window surface. Such buildings are too cold when located in the northern climates, at least. Ade- 312. A sketch showing the effect of thick walls upon the amount of direct sunlight admitted, the greater efficiency of deep windows over shallow windows, and also the effect of over-hanging eaves. FARM SANITATION 509 quate window surface does not add materially to the cost of the construction and should not be admitted for this reason. Wide buildings and basement barns cannot be lighted well, and for this reason should be guarded against. It is to be remembered in this connection that natural lighting is only- one factor in providing sanitary quarters. Cleanliness and ventilation are more important; but none of these features should be neglected. QUESTIONS 1. Describe the changes which have taken place in the natural lighting of farm buildings. 2. What is the threefold purpose of the natural lighting of farm ouildings? 3. What value has direct sunlight in destroying disease germs? 4. Discuss how windows should be located to be the most effective. 5. What should be the general shape of windows, and what may- be said concerning the thickness of casings and width of eaves? 6. Discuss the relation between window surface and floor surface in different types of buildings. CHAPTER LXXX LIGHTING THE COUNTRY HOME Development. It is extremely interesting to study the development of the art of lighting, or illumination; yet it is not the function of this chapter to discuss this phase of the subject. Our fathers and mothers were compelled while young to depend on the tallow candle, the tallow dip, or the light of the fire in the fireplace. History relates how many of our famous men of the past century spent hours in the nickering light from the "back log" poring over a book which they were endeavoring to master. The petroleum industry was not developed until 1860, and the general use of kerosene in lamps did not come until many years after this. The kerosene lamp, when provided with a chimney to control the draft and produce more perfect com- bustion, was a great improvement over the ill-smelling and smoking tallow candle or dip. The various sources of light for rural conditions are the kerosene lamp, the gasoline lamp or system, the acetylene lamp or system, and the electric lighting plant. Alcohol might be burned in lamps, but at its present cost cannot compete with the petroleum oils. These various systems will be discussed in turn. The Unit of Light — The Standard Candle. In comparing lamps it is necessary to refer to the unit of illumination, the standard candle by which all lamps are rated. The standard candle for the United States and Great Britain is the sperm candle seven-eighths of an inch in diameter and burning 120 grains of sperm per hour. This standard is not very satisfac- tory, as it tends to vary. The International Unit of Light FARM SANITATION 511 was adopted by the United States July 1, 1909, and is now the legal unit of light, and is practically equal to the standard candle. The art of measuring the illumination of any source of light is called photometry. The principle involved consists in placing the source of light, or the lamp to be measured and a standard lamp whose candle power is known, at such dis- tances from a screen that the intensity of the light from each is equal. As the light from a lamp passes out in all directions, it is to be expected that the intensity of the light at all points on the surface of a sphere at a certain radius from the source will be equal. As the surfaces of spheres vary as the square of their radii, the intensity of light varies inversely as the square of the distance from the source. This assumes that the source of light is a sphere, which is not true. Kerosene Lamps. Kerosene lamps are still in common use, and, although they have some very serious objections, their merits should not be entirely overlooked. In the first place kerosene lamps are cheap as far as first cost is con- cerned. The fuel is cheap and can be obtained almost any- where. Kerosene lamps are quite safe; in fact, they excel many others in this respect. There- is more danger in the matches than in the lamps themselves. The lamps are readily portable, which is not true of all sources of artificial light. On the other hand there are many disadvantages. The odor of kerosene lamps is not pleasant, although far more offensive to some persons than to others. Kerosene lamps require attention in the way of trimming the wicks and clean- ing the chimneys. If a large number of lamps are to be cared for, the time required daily is considerable. Much heat is developed by a kerosene light, which at times may be a serious disadvantage. The lamp also consumes a large 512 AGRICULTURAL ENGINEERING amount of oxygen and necessitates more rapid ventilation. A large lamp will consume more oxygen than several persons. There is more or less smoke com- ing from the flame, which settles as soot upon the furniture and walls of the room. The light from a kerosene lamp is a yellowish orange. It is not white enough to be a perfect light. Authorities differ in regard to the effect of the light from a kerosene lamp upon the eye, but it is gen- erally regarded as a quite suit- able light. The addition of a mantle, which is a net of rare earths, to a kerosene lamp to in- close the flame, increases the efficiency many fold. This will be shown definitely in the data from tests which will follow. Mantles, however, are very fra- gile and increase the cost of keep- ing the lamp in service. The average kerosene lamp furnishes light at the rate of 15 to 30 candle power. It is to be noted from the table that the mantle has a de- cided effect upon the efficiency of lamps, raising the candle- power-hours per gallon from 600 Fig. 313. A good type of ker- , nr\r\r\ /"< v l osene lamp. The efficiency of to over 3000. Gasoline lamps are tne%^fr u manu e e. d ° ubled by in reality gas lamps, for they FARM SANITATION 513 must convert the liquid into gas before it is burned. Gaso- line lamps are either portable, with an individual generator, or are connected to a system, with a common generator for the entire system. Again, certain gasoline plants require a special grade of light gasoline which is vaporized upon mixing with air. Gasoline Lamps. Gasoline lamps are not as safe as kero- sene lamps, yet when properly handled should not be danger- The efficiency of lamps. Cost per Candle Candle- eandle- Kind of lamp Size Where tested power power-hrs. per gal. power-hr. Kerosene at lie. B. &H. Burner. \ x /l in. dia. la. Exp. Sta. 33.5 877 .0125c Common flat wick XYi in. wide Pa. Exp. Sta. 11.66 591 to .017c 12.91 789 .017c Rochester. \ x /i in. dia. Pa. Exp. Sta. 16.02 19.04 350 to 538 .023c Saronia with Ar- gand burner and mantle % in. dia. Pa. Exp. Sta. 27.46 30.26 1312 to 1515 .008c Chancester with Argand burner mantle Pa. Exp. Sta. 30.6 32.4 3134 to 3402 .0034c ous. They should be filled only by daylight, and care should be taken not to let the gasoline become exposed to the air either through a leak or by spilling. A gasoline lamp, unless of the vaporizing type, requires some time for starting, and must be heated before the gasoline can be generated. While it is burning, there is usually a hissing noise which is very disagreeable. Gasoline lamps are universally mantle lamps, and for this reason are very efficient. The most efficient lamps are those which furnish the liquid to the lamps under pressure. The gasoline lamp consumes the oxygen of the air and heats it much as the kerosene lamp. 514 AGRICULTURAL ENGINEERING Efficiency of gasoline lamps. Kind of lamp Where tested Candle power Candle- power-hrs. per gal. Cost per can- dle-power- hour at 20c. Bracket lamp Hanging lamp Pressure lamp at 34 lbs. Underneath generator la. Exp. Sta. la. Exp. Sta. la. Exp. Sta. Pa. Exp. Sta. 51.2 65.5 300.0 36 to 46 2948 3180 4550 1885 .0068c .0063c .0043c .0120c . 314. A gasoline lamp. The tubini coiled so as to appear in the pic- ture. QUESTIONS 1. What are the improved systems of lighting? 2. How were houses light- ed by artificial means in early times? 3. What is the common unit of light, and explain how it is established? 4. Explain how the illumi- nation of any source may be measured. 5. What are the advan- tages and disadvantages of kerosene lamps? 6. What effect does the use of a mantle have upon the efficiency of lamps? 7. Discuss the merits of gasoline lamps. 8. How does the cost of light from kerosene, alcohol, and gasoline lamps compare? 9. Estimate the cost of lighting the average farm- house during a period of one year with the different systems. CHAPTER LXXXI THE ACETYLENE LIGHTING PLANT The Principle of the Acetylene Plant. When a lighting system for the farm is desired which will furnish the equal of city service, the acetylene plant is one of the first to receive consideration. Acetylene gas is made by bringing calcium carbide in contact with water. In portable lamps the water is allowed to drip upon the carbide ; but with larger plants, the carbide is fed into a rather large tank of water mainly to keep the temperature of the gas as low as possible. The heating of carbide and water is like that of unslaked lime and water, and the resulting residue is the same — nothing more or less than common whitewash. Calcium Carbide.' The calcium carbide is made by sub- jecting a mixture of coke and lime to the intense heat of the electric furnace. The resulting product is of dark-gray color with a slightly crystalline structure. The carbide industry is practically monopolized in this country by the Union Car- bide Sales Company, from which all purchases must be made. Distributing depots are located at various points throughout the United States, there being one in each state, or perhaps more in some instances. The cost of carbide at these depots at the present time is $3.75 per hundred pounds. It is shipped in metal cans as third-class freight. The carbide is no more dangerous than unslaked lime; the only precaution necessary is to keep it free from moisture. There are four sizes of car- bide carried regularly in stock; viz., Lump, Egg, Nut, and Quarter. The last two sizes, Nut Y± inch by % inch, and Quarter, 34 mcn by 1/ 12 inch, are the two commonly used in carbide feed generators. 516 AGRICULTURAL ENGINEERING Acetylene Gas. Acetylene is a colorless, tasteless gas composed entirely of carbon and hydrogen. It is lighter than air, but much heavier than coal gas. Acetylene burns with a very white light, almost like sunlight. It is easy on the eyes Fig. 315. A 35-Iight acetylene generator. and enables one to distinguish colors accurately. The com- bustion of acetylene deprives the air of about 23^> cubic feet of oxygen for each cubic foot burned. The flame, for equal candle power, produces less heat than the kerosene lamp. FARM SANITATION 517 Being a rich gas, acetylene will form a dangerously explo- sive mixture with air; yet an explosive mixture, which must contain between ^ to 25 times as much air as gas, is so unlikely to occur, on account of the ease by which gas leaks are detected, that accidents are seldom heard of. Acetylene gas will cause asphyxiation, yet not nearly so readily as coal gas, which is used for illumination in the cities. No fatal results from inhalation are on record, and it is claimed that death could not occur until the gas was present in the proportion of at least 20 per cent. Production of Acetylene Gas. When calcium carbide is mixed with water, each pound should, if the carbide is chem- ically pure, yield 5}4 cubic feet of gas. This gas is very rich, containing about 1700 British thermal units per cubic foot, nearly three times that of coal gas. The commer- cial carbide yields from 434 to 53^ cubic feet, de- pending somewhat upon its purity, the moisture absorbed, and the amount of dust present. Theo- retically, .562 pounds of water will be needed for each pound of carbide, but in practice as much as eight pounds are sup- plied. The most com- mon size of burner used consumes 3^ cubic foot of gas per hour, and gives a 25-candle-power light. Other standard sizes are the 1, %, and M cubic foot burners. These burners are all forked in Fig. 316. A section of the generator shown in Fig. 315. A is the motor or clockwork for operating the carbide feed, B is the carbide feed, C is the weight for running the motor, D is the carbide bin, E is the agitator in the water tank for storing up the residue before cleaning, F is the gas holder, G is the gas filter, and H is the pipe line to supply lamps. 518 AGRICULTURAL ENGINEERING such a way that two jets of flame are directed toward each other, forming a fan-shaped flame. Mantles are not used with acetylene burners, owing to the fact that it is almost impossible to light the gas without a slight explosion or jar which would destroy the mantle. If mantles could be used they would raise the efficiency of the lamps many fold. Cost of Light. If it is assumed that one pound of carbi de, costing $4 per hundredweight, will furnish five cubic feet of gas, and that a burner using one-half cubic foot per hour will furnish a 25-candle-power light, it is easy to calculate the cost of acetylene light per candle-power-hour for comparison with other lighting systems . Thus if }4 cubi c foot of gas costs 4/10 cent, which is the cost of 25 candle-power-hours of light, one candle-power-hour will cost 1/25 of 4/10 cent or .016 cent. In a test of a portable lamp, made at the Pennsylvania agricultural experiment station, from 127 to 140 candle- power-hours were obtained from a pound of carbide, costing 5 9/10 cents per pound. This would make the cost of light per candle-power -hour .043 cent. Essentials of a Good Acetylene Generator. All acetylene light plants must have a generator whose function is to feed the carbide to the water, or the water to the carbide, which is less usual, as the gas is used. The essentials of a good acetylene generator may be summarized as follows: 1. There should be no possibility of the existence of an explosive mixture in the generator at any time. The National Board of Fire Underwriters has prepared a list of generators which have passed inspection; and each buyer should see that the makeof machine purchased has been inspected and listed. 2. The generator must insure cool generation. 3. The construction must be tight and heavy enough to resist rapid deterioration. FARM SANITATION 519 4. It should be simple in construction so as to be readily understood and not likely to get out of order. 5. It should be capable of being recleaned and recharged without loss of gas into the room. 6. There should be a suitable indicator to show how much carbide remains unused. 7. The carbide should be completely used up, generating the maximum amount of gas. Size and Cost of Plant. Generators are made in various sizes, the rating being based upon the number of 3^-foot lights that can be supplied with gas. The sizes vary from 20-light to 1000-light, but 25, 30, and 35 are the usual sizes. The list prices of these are 120, 135, and 150 dollars, respec- tively. In addition to the cost of the generator, the cost of the piping, fixtures, and installation must be added. For an eight-room house, the total cost will be about as follows : Generator $150 Piping system 40 Drain and foundation for generator 10 Fixtures, eight rooms and basement 40 Barn additional . . 15 Total $225 It is to be understood that this estimate cannot be made very definite owing to the varying number of fixtures required and the cost of labor, freight, etc. QUESTIONS 1. How is acetylene gas made? How is carbide made? 2. Discuss the cost and sizes of carbide. 3. Describe the characteristics of acetylene gas. 4. Discuss the cost of light from acetylene gas. 5. What are the essentials of a good generator? 6. Itemize the cost of an acetylene plant. 7. What care should be used in installing an acetylene system? CHAPTER LXXXII THE ELECTRIC LIGHTING PLANT Development. Two great improvements have recently been brought about which have done much to make the private electric plant far more successful than ever before. In the first place, the new tungsten incandescent lamp has practically reduced the consumption of electricity per candle- power-hour to about one-third the former rate. In the second place, there have been some very decided improvements in storage battery construction, not only making them more reliable, but cheaper. Electric Light. Illuminating engineers agree that the incandescent electric light is the nearest approach to the ideal light that is now to be obtained. Its first great merit lies in its convenience. It is only necessary to turn a button or switch and the light is on or off as desired. It is the cleanest of all lights, no dust, no soot, and no odor. Furthermore, the electric light does not vitiate the air by consuming the oxygen. Of all lights it is by far the safest and may be taken directly into places filled with combustibles. The serious objection to the electric light which has been raised in the past is its cost. The new tungsten lamp has done much to remove this objection, where it can be used, although it is rather fragile and cannot be used where the lamp is subject to shocks or sharp vibrations. Further, the cost of electric light may be somewhat overlooked on account of the advantages enumerated. The first cost of installing an electric plant is large, but not so much greater than the cost of installing an acetylene or gasoline plant. In addition to FARM SANITATION 521 lighting, the electric current may be used for other purposes- small motors, electric irons, etc. The Electric Plant. It does not seem practical to install an electric plant large enough to furnish power to the various machines used on the farm. Not only would the cost of in- stallation be very great, but such a plant when used for light- ing would be very inefficient. An electric lighting plant consists primarily of a source of power or a motor of some sort, a generator or dynamo to furnish the current, the wiring, the lights, and, under all normal conditions, a storage battery to supply cur- rent when the motor and gen- erator are not running. The Source of Power. Water- power makes an ideal power for the plant, as it is almost always very cheap. It is, however, not often available ; hence the princi- pal source of power for the farm electric plant is the gasoline or kerosene engine. These, as has been shown, have developed to the point where they are quite reliable, and the power is furnished in small units at a very reasonable cost. Furthermore, the gasoline engine requires the minimum of attention while running, which is an essential feature of the entire private electric plant. Definitions. In discussing an electric plant, recourse must be made to some electrical terms. Electric current has two properties: (1) The pressure or the voltage, which is the measure of the tendency on the part of an electric current to flow; and (2) the amount of current flowing, or the amperage. Thus a 110- volt lamp requires 110 volts of pressure or voltage to make its filament glow brightly. If the lamp be a 16- candle-power carbon filament lamp only one-half ampere will s the common carbon filament electric lamp; B is the new tungsten lamp, which is much more efficient. 522 AGRICULTURAL ENGINEERING pass through the lamp. The product of the volts by the amperes gives the electric power in watts, the watt being the unit of power. Thus for the lamp just referred to, the current consumption would be 1 10 x^, or 55 watts. One horsepower is equal to 746 watts. The output of dynamos or generators is rated in kilowatts, or units of 1000 watts. Electricity is purchased by the kilowatt-hour, which is electric current at the rate of one kilowatt continued for one hour. One kilo- watt equals 1.34 horsepower; thus to drive a one-kilowatt dynamo, a V/r or 2-horsepower engine is provided, as some power is lost in the friction of the dynamo itself. Selection of the Plant. In deciding upon a plant one of the first questions that arises is the matter of the voltage at which the plant is to be operated. Electric light plants are now made to furnish current at 25 to 110 or even higher voltage. The common voltages are 25, 60, and 110. The lower voltages have some advantages; viz., (1) first cost of the storage battery is lower; (2) the battery has fewer parts; (3) it can be used better with low candle-power lamps; and (4) the lamps, having shorter filaments, are stronger. The disadvantage of a low voltage lies primarily in the fact that it is not standard with any lighting plants and is inconvenient to procure lamps and other fixtures for it. There is a decided saving with high voltage, however, in connection with the wiring, especially if the current is to be transmitted far, since the size of wire required to furnish a given light with electricity varies inversely with the voltage. In other words, a wire will transmit twice as much electricity through a given size at 110 volts as at 55 volts. If the maximum number of 25-watt lamps in service at one time does not exceed 20, or the demands upon the dynamo from miscellaneous sources such as motors, flat iron, etc., does not exceed 500 watts, a one-half kilowatt generator may be used. A one-horsepower gasoline engine will furnish FARM SANITATION 523 the power unless required to do other work while running the generator. If pumping, churning, and other forms of light work are contemplated, a two-horsepower engine will usually be found very satisfactory. The storage battery must con- tain 56 cells, and if they are of the 20-ampere-hour size they will furnish all of the lamps with current for four hours. Engine, dynamo, storage battery, and switchboard of an elec- tric lighting plant. The Cost of the Plant. The total cost of plant may be estimated as follows: 1 2-horsepower gasoline engine $125 1 J^-kilowatt generator 60 1 storage battery, 20-ampere-hour, 56 cells at $2.50 140 1 complete switchboard 75 17 tungsten lamps 17 12 carbon lamps 3 Wiring 50 Fixtures 30 Total cost $498 The Cost of Light. The cost of operating the plant will be principally that of gasoline, which, at the usual price, will 524 AGRICULTURAL ENGINEERING be between 1% and 2 cents per hour. Twenty 25-watt lamps will furnish 400 candle-power. Thus the cost per candle- power-hour might be at a minimum .00375 to .005 cents. As the plant will seldom be operated at full capacity, the aver- age cost will be much greater, perhaps double. Operation. The electric plant is not difficult to operate by one who has some knowledge of electrical machinery. The engine and the dynamo will not require a great amount of attention. The storage must be supplied with electrolyte from time to time. The battery is also the least durable part of the entire plant. Perhaps a new set of electrodes for the battery will be needed at the end of five years. A good engine ought to last at least ten years. QUESTIONS 1. What improvements have made the electric lighting plants practical for farm homes? 2. What are the advantages of electric light? 3. Discuss the most serious objections to electric light. 4. Is it generally practical to install an electric lighting plant large enough for power service? 5. Discuss the various sources of power for electric lighting plants. 6. Define voltage. Amperage. 7. What is a watt? A kilowatt? 8. What is the relation between watts and candle power with tung- sten lamps? 9. What are the advantages of a low-voltage system? 10. What are its disadvantages? 11. Itemize the cost of an electric lighting plant. 12. Discuss the cost of electric light. 13. Discuss the care and maintenance of an electric lighting plant. CHAPTER LXXXIII HEATING THE COUNTRY HOME Systems of Heating. There are four systems of heating farm houses in use : 1. By stoves. 2. By a hot-air furnace. 3. By a hot-water furnace and radiators. 4. By a steam furnace and radiators. Stoves. The first of these is in common use, and perhaps little can be written here which will add to the general infor- mation upon the subject. The stove was invented to burn coal shortly after coal was discovered, for the fireplaces of the time were not adapted to the purpose. As usually designed the stove is not an efficient device, as perhaps 50 per cent of the heat is lost up the chimney. It has other more serious shortcomings, however. In the first place the stove d ">es not produce a uniform temperature, owing to the fact that the air circulation within the room is not perfect. The success of any heating system depends primarily upon perfect circulation of the air. Air near the hot stove expands upon heating, becomes lighter and rises to the ceiling, and colder air takes its place. As the warmest part of the stove is several feet from the floor, the upper part of the room is usually much warmer than the lower. The inconvenience of handling and storing the fuel in the room, and the dirt, smoke and gases that are apt to result are also objectionable. If several rooms are to be heated, the management of the stoves becomes a troublesome matter. Almost any kind of fuel may be used in a stove, which is an advantage decidedly 526 AGRICULTURAL ENGINEERING in its favor. Although coal requires less labor, wood is a clean and very desirable fuel. In certain sections of the country the fuel used is mainly corn cobs and other trash, and the stoves used are the so-called air-tight stoves which have a large magazine into which a bushel or more fuel may be placed at one time. This magazine obviates the necessity of feeding the fuel at short intervals. There is, however, some danger from the explosion of the gas which is generated from fresh fuel before the flames start. The heat of the smoulder- ing fire upon which fresh fuel is placed drives off certain combustible gases, which are ignited as soon as a flame starts up. By far the most satisfactory stove for the cold winters of the North is the hard-coal burner. When of sufficient size and well designed, with a good large magazine, the hard-coal burner may be used to heat several rooms to a comfortable temperature. The high cost of hard or anthracite coal in certain sections of the country renders the use of such a heater quite expensive. Radiators. In houses equipped with stoves an upper room can be comfortably heated by extending the stove pipe into the room and providing a radiator. This plan is highly commendable, as there is no additional expense connected with its use other than the cost of the radiator, which should not exceed $8, the value of a good one. Warm-Air Furnaces. Heating houses by means of warm- air furnaces does not differ materially from the use of stoves. The furnace is simply a large stove placed in the basement, with pipes to convey the heated air to the various rooms above. By placing the furnace in the basement many of the objections to the stove are overcome. First, the dirt con- nected with the firing and cleaning is kept where it is least objectionable. Proper circulation of the air may be secured FARM SANITATION 527 by arranging the pipes so that the temperature may be kept uniform in all parts of the house. The warm-air furnace has an advantage in that a house may be heated up quickly, and likewise the disadvantage that the house will cool quickly when the fire goes down, owing to the fact that there is no storage of heat. The hot-air furnace is very bad about conducting dust and smoke into the rooms. Often cheesecloth strainers are provided in the fresh air out- lets to keep out the dust. The average life of a hot-air furnace will not exceed 8 to 10 years, and when it becomes old the plates are quite apt to be cracked or warped in such a way that there is a serious leakage of smoke and gas into the rooms. It is to be noted in this connection that the furnace is so large that it must be built in sections, and seams cannot be avoided. As air does not have the property of absorbing a large amount of heat quickly, the plates and castings are easily overheated. In strong winds the circulation of the air in the flues is seriously interfered with. Often there is a corner room more exposed than the others that cannot be heated with the hot- air system. Installation. In planning a house in which the warm-air system is to be used, thought should be taken to give the fur- nace a central location, that there shall be no long horizontal air pipes through which it will be difficult to start a draft. The size of the hot-air furnace is usually designated by the diameter of the fire pot, which ranges from 20 to 30 inches A typical warm-air furnace. 528 AGRICULTURAL ENGINEERING and over. The hot-air system of heating is much less expen- sive, as far as cost of installation is concerned, than the hot- water or steam system. The cost of a first-class furnace with double pip- ing to protect the wood- work from becoming over-heated, in a house of six rooms, ought not to exceed $200. The Hot-Water Sys- tem. The hot-water fur- nace with suitable radi- ators represents the most perfect system of house heating, but it is the most expensive of all and is slightly more difficult to regulate. Water is heated by the furnace, and the consequent ex- pansion and reduction in weight cause it to flow to the radiators above, where it becomes cooled and consequently heav- ier, causing it to flow downward to be heated Fig. 320. A hot-water heating system, again. An expansion The locomotive type of furnace or boiler, -j 1 U although not in general use, is said to be tank IS provided aDOVe quite satisfactory. ^ ^ ^^g fo &c _ commodate the extra volume of the heated water. The success of the hot- water system consists in providing a fur- FARM SANITATION 529 nace, piping, and radiators of sufficient size. The capacity of a furnace depends primarily upon its heating surface, al- though the size is commonly designated by the size of the fire pot. Radiators. Radiators, designed to give off heat from the water heated in the furnace, are made of cast iron, pressed steel, or pipe. In any case the amount of heat furnished is determined by the amount of surface from which the heat may radiate. This is always measured in square feet, and one feature of the design of a hot-water system is to provide a sufficient amount of radiating surface to heat each room. Radiators may be obtained with greater or less number of sections in various sizes, to furnish any amount of radiating surface desired. Estimating the Radiation. One rule for determining the amount of radiation for climates where the temperature occa- sionally falls below zero is as follows : cubical contents of room Square feet of radiation = — — — ■ — — ■ ■ — ■ -(- 200 square feet of glass + lineal feet of exposed wall. 2 The hot-water system will successfully heat rooms on the side of the house exposed to strong wind. It is much cleaner and the plant will last at least twice as long as the hot-air system. The cost will, however, be from one-half to double that of the hot-air system. It is claimed that the hot-water system uses one-third less fuel than the hot-air furnace. A steam system may be installed for heating residences, but it requires close attention and so is seldom used. In large buildings and factories it is universally used, the use of steam reducing to some extent the size and cost of piping. 530 AGRICULTURAL ENGINEERING QUESTIONS 1. What are the four systems of heating farm houses now in use? 2. Discuss the advantages and disadvantages of stoves. 3. What are the fuels commonly used in stoves, and what are the advantages of each? 4. What is considered the most satisfactory stove for cold climates? 5. How may upper rooms be heated with the stoves below? 6. What are the advantages of a warm-air furnace over stoves? 7. How durable is the warm-air furnace? 8. How much will a warm-air furnace installation cost for a six- room house? 9. What arc the advantages and disadvantages of the hot-water syst em? 10. Upon what does the capacity of a hot-water furnace depend? 11. Of what materials are radiators made? 12. Explain by a practical example how the radiating surface required for a house may be estimated. 13. How will the cost of a hot-water system compare with a warm- air system? 14. What are some of the objections to a steam heating system for farm houses? CHAPTER LXXXIV VENTILATION OF FARM BUILDINGS Importance of Ventilation. One of the most important features involved in the design of farm buildings is that of ventilation. It is generally recognized that men and animals must have fresh air, and the most favorable conditions for life and health are attained when the air is as pure as the open atmosphere. It is not practical to provide air as pure as this to animals housed in buildings designed primarily for shelter and warmth. The Standard of Purity. The standard of purity, or the extent to which pure air may be vitiated with expired air and still be fit to breathe, is a much-argued point. For conven- ience, the purity of air is designated by the number of parts of carbon dioxide in 10,000 parts of air. Pure air contains about four parts of carbon dioxide in each 10,000 parts. De Chaumont, an authority on ventilation, holds that six parts of carbon dioxide in 10,000 parts of air should be the standard, and other authorities recommend various and greater amounts. The late Professor F. H. King, of Wiscon- sin, recommended 16 parts as the correct standard, but em- phasized the great need of experiments to determine definitely the correct standard. There is little doubt but that if this lower standard were maintained generally, ventilation condi- tions would be much better than they are now. Purpose of Ventilation. The purpose of ventilation is threefold: (1) To supply pure air to the lungs of the animals; (2) to dilute and remove the products of respiration; and (3) to carry away the odors or the effluvium arising from the 532 AGRICULTURAL ENGINEERING excreta. The first of these is the all-important purpose; for no animal can live more than a few minutes without air, but is able to go for some time without either food or water. The quantity of air breathed daily by an animal greatly exceeds the total quantity of food and water. This is indicated by the following table: Amount of air breathed by different animals. {Collins Table.) Per hour Per 24 hours Cu. ft. Pounds Cu. ft. Horse 141.7 272 3402 Cow 116.8 224 2804 Pig 46.0 89 1103 Sheep 30.2 58 726 Man 17.7 34 425 Hen 1.2 2 29 To maintain the standard set by Professor King, which requires that the air at no time shall contain more than 3.3 per cent of air once breathed, the following amounts of air will be required each hour for the various animals indicated. This standard may be stated as 96.7 per cent, representing the purity of the air, and, as before stated, it is equivalent to between 16 and 17 parts of carbon dioxide per 10,000 parts of air. Amount of air required per hour to maintain a standard of g6.J per cent. Horses 4296 cu. ft. per head Cows 3542 " " Swine 1392 « " Sheep. . 917 " " Hens 35 " " Man 537 " " Ventilation finally resolves itself into the problem of find- ing a process of dilution or mixing the air in the building with FARM SANITATION 533 fresh air fast enough to prevent the air from becoming foul beyond the permissible standard. The process of dilution may be accomplished in at least four different ways, as follows: 1. By a process of diffusion through cloth curtains. 2. By the action of winds. 3. By the difference in weight of masses of air of un- equal temperature. 4. By mechanical methods. Cloth Curtain Ventilators. Poultry houses quite gener- ally and dairy barns in several instances have been ventilated by providing thin muslin or cheesecloth curtains in place of the usual window glass. The theory of ventilation in this case holds that there is a diffusion of the foul air outward and the pure air inward through these curtains. Experiments which have been conducted to date, to deter- mine definitely the efficiency of this system, would indicate that it is unsatisfactory and unreliable. It is quite possible with any reason- able amount of curtain surface to provide the necessary pure air. Action of Winds. The action of the winds is one of the sim- plest methods of producing venti- lation. For instance, the wind pro- vides ventilation when two windows are opened on opposite sides of a 321. A window ar- ranged so as to allow air to enter with the least draft. It may be hinged at the bottom building. Such an arrangement and made to close between the side pieces. would not be satisfactory on ac- count of the direct drafts produced, subjecting the animals to chills. The dangers from drafts are overcome to a large extent by providing suitable inlets and outlets. 534 AGRICULTURAL ENGINEERING The Sheringham valve makes a satisfactory inlet. This is arranged by hinging the window at the bottom and allow- ing it to drop inward at the top between cheeks or triangular- shaped side pieces. The air in striking the inclined window is thrown upward toward the ceiling and is not allowed to pass directly onto the animals which may be housed in the building. The fresh air is diffused through the room and the foul air passes out through suitable flues, not unlike those to be described later. Cowls or cupolas are used in connection with outlet flues and are designed in such a manner that the winds in blowing across them produce a suction or aspirating effect in the flues. Temperature System. The principle that heated air rises is the theory basis of the majority of the successful ventilating systems now in use. The King system, named after the designer, the late Professor F. H. King, uses this principle as well as the principle that foul air is heavier than pure air when both are at the same temperature, and tends to settle towards the floor. For this reason, the inlets in the King system discharge pure air near the ceiling and the out- let flues receive the air near the floor. Fig. 322 ; Showing one method of ar- ranging ttie outlet flues in the King sys- tem. The flues may be brought together to form a common outlet. FARM SANITATION 535 J (7 y Size of Inlets and Outlets. Professor King advises four square feet each of outtake and intake flues for each 20 adult cows, for an outlet flue 20 feet high; or, in other words, 36 square inches of cross section of flue should be provided for each cow. If the outlet flue be 30 feet high, 30 square inches of cross section will be sufficient. To be successful, there should be a rather large number of intakes and few out- takes. The outtakes should be air-tight, as straight as pos- sible, and as smooth as practical on the inside. One common ^ cause of failure of this system of m ventilation is incorrectly con- structed outtakes or outlet flues. Often the flues are made of one thickness of tongued and grooved lumber which dries out and leaves open cracks which prevent the flues from working. Again, it is a com- mon occurrence to find that the flues are made with many sharp turns which restrict the flow of air through them. A good cupola, so designed as to produce a suction on the flues connecting into it when the wind is blowing, increases the efficiency of the system materially. Mechanical Ventilation. Mechanical ventilation is prac- tically unknown at the present time for farm buildings. It consists in providing fans or other positive means of forcing air into or out of a building, and is considered the only modern method of ventilation. The time may come when it will be considered in connection with farm buildings. All other systems depend more or less upon varying conditions of wind and temperature, which cannot be controlled. TTTTT 1 Fig. 323. Different methods of arranging the inlet flues in the King system of ventila- tion. 536 AGRICULTURAL ENGINEERING QUESTIONS 1. Why is the adequate ventilation of farm buildings important? 2. Explain what is meant by "standard of purity." 3. What are some of the standards recommended? 4. What is the three-fold purpose of ventilation? 5. How much air is breathed per hour by the various farm animals? 6. How much air is required per hour for each of the various farm animals to maintain a standard of 96.7 per cent purity? 7. In what four ways may ventilation be secured? 8. Describe the construction and discuss the efficiency of cloth- curtain ventilators. 9. How may the action of the wind be used in securing ventilation? 10. Describe the Sheringham valve. 11. What is the purpose of cowls or cupolas on ventilating flues? 12. How may the heating of air be used as a basis of ventilation? 13. Describe the construction of the King system of ventilation. 14. What are the possibilities for mechanical ventilation? LIST OF REFERENCES Rural Hygiene, Henry N. Ogden. Sanitation, Water Supply, and Sewage Disposal of Country Houses, Wm. Paul Gerhard. Electric Light for the Farm, N. H. Schneider. Disposal of Dairy and Farm Sewage and Water Supply, Oscar Erf. Bulletin 143, Kansas Agricultural Experiment Station. Sewage Disposal Plants for Private Houses, A. Marston and F. M. Okey. Bulletin VI, Vol. IV., Iowa Engineering Experiment Station, Ames. Sanitation and Sewage Disposal for Country Homes, William C. Davidson, Bulletin No. 3, Missouri Engineering Experiment Station. Electric Power on the Farm, Adolph Shane. Bulletin 25, Iowa Engineering Experiment Station, Ames. Ventilation, F. H. King. PART NINE— ROPE WORK CHAPTER LXXXF ROPE, KNOTS, AND SPLICES A practical knowledge of the correct ways of tying, hitching, and splicing ropes is valuable to any farmer. His work is such that an extended use must be made of ropes; and such knowledge will not only be convenient and save time, but will also be a means of averting accidents. Only the more important knots, hitches, and splices will be dis- cussed. Kinds of Rope. Mention has been made in a former chapter concerning the various kinds of rope in use for transmitting power. The rope used for general purposes about the farm is hemp rope. As most of it is made from Manila hemp imported from the Philippine Islands, it is generally known as Manila rope. Cotton rope is some- times used for halters or ties. In making rope, the fibers are first spun into a cord or yarn, being twisted in a direction called "righthand." Sev- eral of these cords are then made into a "strand" by being twisted in the opposite direction, or "left-hand." The rope is finally made up of three or four of these strands twisted "righthand," and is known as a three- or a four-strand rope, depending upon the number of strands used. The four- strand rope is constructed on a core, and is heavier, more pliable, and stronger than the three-strand, in any given size. Strength of Rope. The following table gives the strength and weight of some of the common sizes of three-strand Manila rope when new and free from knots. The smallest 538 AGRICULTURAL ENGINEERING size of pulley upon which the rope should be used is also given. The working strength, or the greatest load the rope should carry with safety, is given as about one-seventh of the breaking load. Strength of different sizes of three-strand Manila rope, and size of pulley to use. Diameter of- Diameter 100 lbs. rope Safe load Breaking load pulley Inches Pounds Pounds Pounds Inches l A 3 55 400 2 v% 5 130 900 3 y* 7.6 230 1620 4 Vs 13.3 410 2880 5 H 16.3 520 3640 6 Vs 23.6 775 5440 7 1 28.3 925 6480 8 Good Knots. The three qualities of a good knot have been stated as follows: "(1) Rapidity with which it can be tied; (2) its ability to hold fast when pulled tight; and (3) the readiness with which it can be undone." In Kent's Mechan- ical Engineer's Pocket Book it is stated, "The principle of a good knot is that no two parts which would move in the same direction if the rope were to slip should lay along side of, and touching, each ther." Parts of the Rope. For the sake of clear- ness in the discussion of knots which is to follow, the student should understand what is meant by the following parts of a rope : The The standinq part is the long unused parts of a rope: a r o b b!-hr n c ?o a rt - P ar * °^ ^he ro P e > as represented by A, D, end. ' ' ° ' Fig. 324. The bight is the loop formed whenever the rope is turned back upon itself, as B. ROPE WORE 539 Square, or reef knot. The end is the part used in leading the rope, as D in the figure. A loop is made by crossing the sides of a bight, as C. KNOTS The square or reef knot is one of the commonest knots used in tying together ends of ropes or cords. It is the knot that can best be used in bandaging or in tying bundles. It does not slip and is quite easily untied. In tying the square knot, the ends are crossed, bent back on themselves, and crossed again, making the outside loop pass around both strands of the opposite end. As usually tied both ends are on one side instead as shown in Fig. 325. The Granny or False Reef Knot. If the ends of the rope are crossed finally in the wrong direction, the result is not the true square knot but what is known as the granny or false reef knot, as shown in Fig. 326. This knot, when compared with the true reef knot, illustrates the first principle of knots. It is not a good knot, and is given to explain this principle. The sheet bend or weaver's knot is universally used by weavers in tying together two ends of threads and yarns, Granny knot, or false reef. Sheet bend, or weaver's knot. 540 AGRICULTURAL ENGINEERING Bowline knot. and is a good knot inasmuch' as it is very secure, can be rapid- ly tied, and easily untied. This knot is tied by forming a loop with one rope end, as shown in A, Fig. 327, and then passing the other end back through this loop, as shown at B. When pulled tight the knot takes the form shown at C. The bowline knot is the best knot for forming a noose or loop which will not slip when under strain, and which can be easily untied. Fig. 328 shows one method of tying the bowline. In tying this knot a loop is formed in the standing parts of the rope, as shown at the left in Fig. 328 ; then the end of the rope is passed through this loop around the rope and back through the loop, as shown at the right. This, perhaps, is the simplest way of tying this knot, but there are several other ways. s,i P knot - The halter, slip, or running knot is used where it is desired that the rope shall bind, as on a post when tying a halter rope. This knot is made by bending the end of the rope over itself and carrying it around the standing part of the rope and back through the loop thus formed. Often, in tying a halter rope, it is safer to use a bight of the rope through the knot and then pass the end of the rope through the loop so formed, as shown in Fig. 330. This knot unties somewhat more easily. 329. 330. Hitchin ROPE WORK 541 HITCHES The Half Hitch. The half hitch, as shown in Fig. 331, is not very secure, but is easily made. The clove hitch, as shown in Fig. 332, is more secure than the half hitch. It is often used to fasten timbers together. The Timber Hitch. The timber hitch, (Fig. 333) is used in attaching a rope -to timber, for hauling, and similar purposes. It is made by leading the end of the rope around the timber, then around the standing part, and back, making two or more turns on its own part. The strain in the rope will prevent the rope from slipping. The Blackwall hitch is used to attach a rope to a hook; and, al- though simple, it holds the end very securely. See Fig. 334. Two Half Hitches. Two half hitches may be used to good advantage, for they prevent the rope from slipping under any strain. They are easy to form, as may be learned from Fig. 335. The Sheepshank. The sheepshank is used in shortening a rope. It is made by gathering up the amount to be shortened and taking a half hitch around each end, as shown in Fig. 336. If it is desired to make the knots more secure, the ends of the rope may be passed through the bights. FINISHING THE END OF A ROPE Whipping. Whipping is one of the best ways of prevent- ing a rope from raveling; and, as the size of the rope is not Clove hitch. Timber hitch. 542 AGRICULTURAL ENGINEERING ■ig. 334. Black- wall hitch. materially increased, it can be used where the rope is to pass through pulleys and small openings. Good, stout wrapping cord should be used for the whipping. A loop of cord is laid along the end of the rope, as shown at A, Fig. 337. The loop is then used to wrap the rope, allowing the side of the loop to pass over the end of the rope. After the rope has been wrapped for a sufficient distance, the ends of the cord are pulled tight and then cut off, as shown at B. Crowning the end of a rope consists in unraveling it for a short distance, usually 5 or 6 inches ; then knotting the strands and turning them back and weaving them into the rope. This increases the size of the rope end, but makes a very firm finish. The strands are first knotted as shown at A, Fig. 338. Then with the aid of a pointed, smooth, hardwood stick the loose strands are woven al- ternately over and under the strands in the rope. When passed under three or more strands of the rope in this manner, the end of each loose strand may be cut off. To prevent kinks and to make a smoother finish, the loose strands may be slightly untwisted as they are woven into the rope. When finished, the crown should have shefpshamc the appearance of D, Fig. 338. ROPE WORK 543 "Whipping SPLICING The Short Splice. The short splice makes the rope larger at the splice, as a double number of strands are woven into the rope at one place. Thus in case of a three-strand rope the splice is six strands thick at the splice. This splice cannot well be used where the rope is to run over pulleys. To make the short splice, the ends of the rope are unlaid for a suitable length, which will vary from 6 to 15 inches, depending on the size of the rope. The strands are then locked together by tying by pairs strands from opposite ends of the rope, with a simple overhand knot, as shown at B, Fig. 339. After tying, the strands are woven into the rope in each direction by opening the rope with a hardwood pin and tucking them under every other strand of the rope. This tucking may be repeated two or more times and the ends then cut off, leaving a splice as shown at D. The Long Splice. The long splice is not so bulky as the short splice, and should be used where the rope is to run 544 AGRICULTURAL ENGINEERING over pulleys. It is so made that ends of the strands are joined at different places, making the largest number at any one place only one greater than the number of strands in the Short splice rope. Thus with a three-strand rope the number of strands through the splice is four. In making the long splice, a much longer length of each end of the rope is unlaid. For a ^§-inch rope, this should be about 18 inches; for a 3^-inch rope, 24 inches; for a ^-inch rope, 36 inches; for an inch rope, 36 Fig. 340. Long' splice, three-strand rope. inches and so on. After unlaying the rope ends for the proper distance, they are locked together as shown at A, Fig. 340. By unlaying one strand from each of the rope ends and filling ROPE WORK 545 in with one of the loose strands, bring the splice into the form shown at B. Then tie the strands and weave the loose ends into the rope as in the case of the short splice, as shown at C, finishing the splice as shown at D. The Side Splice. The end of a rope may be joined into the side of the rope in a similar way, as is shown in Fig. 341. Rope Halters. Rope halters can be conveniently made in a variety of forms, as shown in A, B, and C, in Fig. 342. The size of these halters will depend upon the size of the animals for which they are intended. Fig". 342. Rope halters. Their making does not require the use of any new princi- ples other than those discussed. QUESTIONS 1. To what practical use may a knowledge of knots be put? 2. Of what materials are ropes made? 546 AGRICULTURAL ENGINEERING 3. Describe the making of a rope. 4. What size of rope should be used for a 500-pound load? A 1000-pound load? 5. What are three qualities of a good knot? 6. What is the most important principle of the knot? 7. Name and describe the parts of a rope. 8. Describe the following knots, and explain where they arc useful : The square or reef knot; the granny knot; the weaver's knot; the bow- line knot; the halter or slip knot. 9. Describe the following hitches and their use: The half hitch; the clove hitch; the timber hitch; the Blackwall hitch; two half hitches. 10. What is the sheepshank used for? Describe how it is made. 11. Explain how the end of a rope may be finished by whipping. By crowning. 12. Describe the making of a short splice. The long splice. The side splice. 13. Describe how three styles of halters may be made. INDEX Acetylene plant, 515; cost of, 519; generator, 517; produc- tion of gas, 517. Agricultural Engineering, de- fined, 13. Air, amount breathed by ani- mals, 532; amount in gas mixtures, 350; standard of purity of, 531. Air pressure water system, 494. Alfalfa, under irrigation, 119. Alfalfa harrow, 217. Ammeters, 358. Angle of incidence of sun's rays, 507. Angle of traces, 331. Areas, computing, 34; problems, 37. Arrows. 21. Ash wood, use in tools, 196. Babbitting boxes, 192. Ball bearings, 191. Balloon frame, for houses, 455. Barns, dairy, 436; horse, 442; round, 449. Barn framing, 445. Basin method of irrigation, 132. Bathroom fixtures, 499. Batteries, 358. Beams, strength of, 406; form- ula for, 408. Bearing of a line, 53; of a plow, 201. Bearings, ball, 191; adjust- ment of, 193; harrow, 218; ring oiling, 191; roller, 191; self-aligning, 190. Beech wood, 196. Belting, 320; canvas, 321; horsepower of, 320; lacing of, 322; leather, 321; rubber, 321. Bench marks, 43, 49. Bending moment, 406. Berm, 104. Bessemer steel, 197. Binder, grain, 244; adjustment, 248; causes of failure to tie, 248; engine drive, 246, 269; operation of, 246; selection, 244; size, 244; tongue truck, 246. Birch wood, for machines, 196. Blower, ensilage, 275 ; thresher, 280. Boiler, steam, 376; capacity of, 379; .locomotive, 378; management of, 383; return flue, 379; vertical, 377. Boiler feeder, 382. Border method of irrigation. 133. Boxes, of machines, 190; bab- bitting, 192; enclosed wheel, 191. Brick, building, 410. Brick roads, 165. Bridges, concrete, 177; design of, 175; foundation for, 177; importance of, 175; size, 175. Bridging, 456. Brooks, as farm water supply, 484. Bubble tube, 44. Buildings, farm, capital invest- ed in, 395; heating, 525; lighting, 506; location of, 395; ventilation of, 531. 548 INDEX Cable transmission, 324. Calcium carbide, 515. Canals, 122. Candle, standard, 511. Canvas belting, 321. Capillary water, 57. Carburetors, 345, 351. Carriers, hay, 271. Cart, harrow, 213. Cast iron, as machine material, 196. Cast steel, 197. Catch basin, 99. Cement, Portland, 410. Center, dead, 387. Cesspool, 501. Chaining, 23, 24. Check method of irrigation, 131. Chilled cast iron, 197. Clay roads, 153. Clutch, on tractors, 372, 392. Coefficient of friction, 188, 189. Combustion of gases, 344, 350. Compass, 53. Component forces, 314. Compound engines, 386. Compression, 352. Concave, 279. Concrete, 411; proportions for. 412; reinforcement of, 412. Concrete roads, 166; bridges, 177. Connecting rod, 385. Contour maps, 52. Corn harvesters, 251; binders, 252; huskers, 256; pickers, 254; shocker, 254; shredder. 256; sled cutters, 251. Corn planters, 231; adjust- ment, 236; conveniences, 235 ; dropping mechanisim 226; essentials of, 231; fur- row-openers, 234; graded seed for, 238; wheels, 234; variable drop, 233. Correction lines, 39. Cow ties, 440. 'Crank shaft, 385. Crowning a rope, 542. Crown sheet, 378. Cultivators, 237; construction, 238; balance frame, 240; disk, 242; guiding devices, 241; seats, 241; selection of, 237; surface, 242; walk- ing, 238; wheels, 240. Culverts, 175; concrete, 178; design of, 175; importance of, 175; pipe, 178; size, 175. Cutters, ensilage, 273; con- struction, 276; elevating me- chanism, 275; mounting, 275; selection of, 276; self-feed, 275; types, 273. Cylinder, 488; threshing, 278. . Dairy barns, 436; construction details, 437; essentials of, 436; types, 436. Datum, 42. Dead center, 387. Declination of the needle, 53. Deep-tilling machine, 206. Deere, John, 181. Differential, 393. Disk harrow, 213. Disk plow, 204. Ditches, cost of digging, 101; digging for tile, 86, 93; fill- ing, 96; grading, 89; open, 103. Ditching machines, 87. Draft, of plows, 204; principles of, 330. Drainage, 56; benefits of, 61; districts, 108; history of, 56; land drainage, 86; lands needing, 58; open ditch, 103; systems of, 67; underdrain- age, 59. Drainage districts, 108; assess- ments, 109; defined, 108; laws for, 108 ; survey of, 109. Drainage engineer, 64. Drainage system, 67. Drainage wells, 100. INDEX 549 Drawing instruments, 28. Drills, 225; adjustment of, 229; force feeds, 227; furrow- openers, 225; horse lift, 229; press drill, 228; seed tubes, 228; selection of, 228. Dynamometers, 317. Dynamos, 358. Earth, roads, 147; construction, 147; crown, 149; drainage of, 147; extent, 147; grades, 151; maintenance, 150. Efficiency of lamps, 513; of a machine, 186. Elasticity, denned, 404. Electric light, 520; cost of, 524; plant, 521; selection of plant, 522; source of power, 521. Electrical terms, 522. Elements of machines, 186. Elevation of a point, 42. Elevators, ensilage, 275; por- table farm, 287. Energy, kinds denned, 313. Engineer, drainage, 64. Engineering, defined, 13. Engine gang plows, 208. Engines, gasoline or oil, 344; measuring power of, 316: operation of, 350; steam. 376, 385; tractors, 370, 389. Ensilage machinery, 273. Equilibrium, defined, 402. Essentials of a machine, 187. Eveners, 334; four-, five-, and six-horse, 336; placement of holes, 334; plain, 337; three- horse, 335. Factor of safety, 405. Fanning mills, 282. Farmhouse, the, 451; con- structing, 455; features of construction, 451 ; location of, 451; plan of, 452. Farm machinery, 180. Farm mechanics, defined, 15. Farm sanitation, 480. Farm structures, 395. Feed mills, 298. Feed water heater, 382. Fields, leveling, 52. Fixtures, bathroom, 499 ; plumbing, 497. Flagstaff, 21. Flooding method of irrigation, 131. Flow of water, in ditches, 105; in pipes, 491; in tile, 78. Foaming in boilers, 383. Foot pound, defined, 314. Force, action of, 402; defined, 314. Forks, hay, 270. Friction, coefficient of, 188, 189; defined, 187; of rest, 188; rolling, 188. Friction gearing, 325. Fuels, for engines, 344. Full frame, 445, 455. Furnaces, for boilers, 377; for houses, 526. Furrow method of irrigation, 133. Fusible plug, 382. Gang plows, 201; engine, 208. Gas mixture for engines, 350; testing, 352. Gasoline engines, 344; classes, 344; estimating horsepower of, 367; four-stroke cycle, 346; fuel for, 344; operation of, 350; for pumping, 486; selection of, 361; testing, 366; two-stroke cycle, 347; types, 345; use on binders, 246, 364. Gasoline lamps, 514. Gas tractors, 370. Gauge, cocks, 380; glass, 381; pressure, 381. Gearing, for transmitting pow- er, 324; traction, 373, 393. 550 INDEX Governor, engine, 387. Graders, grain, 282. Grading tile drains, 73, 89. Grain, under irrigation, 118. Graphite, as a lubricant, 189. Gravel roads, 154; binder, 155; cost of, 158; drainage of, 156: maintenance of, 158; surface construction, 156. Grease cups, 192. Grip, of horse, influence on draft, 331. Gunter's chain, 18. Gunter's chain measure, 19. Halters, rope, 545. Harrow attachment for plows, 219. Harrows, 211; cart for, 213; construction of, 212, 215; disk, 213; smoothing, 211; spring-tooth, 213. Harvester, corn, 251; grain, 244. Hav machinery, barn, 270; field, 258. Heating systems, 525; fur- naces, 526; stoves, 525. Hickory wood, qualities and uses, 196. Hillside plow, 207. Hitch, length of, influence on draft, 332. Hitches, 541. Hog houses, 414; individual, 417; large, 419. Horse, amount of service from, 329; as a motor, 327; capa- city of, 328; draft, 330; size of teams, 329; weight, etc. of, influence on draft, 330. Horse barns, features of con- struction, 442. Horsepower, 314; estimating, engines, 316, 366. Hot water heating system, 52S.- Husker, corn, 256. Hussey, Obed, 181. Hydrostatic water, 57. Ignition, in oil engines, 354; jump-spark system, 357; make-and-break system, 355. Implement, defined, 186. Implement house, 473; details of construction, 474; loca- tion, 473; size, 473. Incandescent lamp, 521. Injector, 382. Instruments, for leveling, 42; for measuring, 18. Iowa silo, 469. Iron, cast, 196; wrought, 197. Irrigation, 111; amount of wa- ter used in, 117; applying water in, 129; crops grown by, 118; history of, 112; pre- paring land for, 130; pur- poses of, 113; sewage dis- posal by, 138; supplying water for, 122. Irrigation culture, 115; in humid regions, 136. Jacks, lifting, 287. Journal, 190. Jump-spark ignitors, 357. Kerosene lamps, 511. Knots, essentials of a good, 538; kinds, 539. Knotter, binder, 248. Kutter's formula, 105. Labor, farm, influence of ma- chinery on, 181; of inconven- ient buildings on, 395. Lakes, as farm water supply, 484. Lamps, efficiency of, 513; gas- oline, 514; kerosene, 511. Land rollers, 220. Laundry, in farmhouse, 454. Laying out the farm, 396. Leaks, in oil engines, 353. INDEX 551 Leather belting, 321. Lettering, 32. Level, 45; adjustments of, 46. Leveling, definition of terms, 42; practice, 49; tile drains, 73. Light, unit of, 511. Lighting systems for buildings, acetylene, 515; development, 510; lamps, 511; natural, 506; electric, 520. Lime, for motar, 410. Linear measure, 19. Liners, 193. Link belting, 323. Loaders, hay, 266. Locomotive boiler, 378, 528. Lubrication, 189; choice of lubricant, 189. McCormick, Cyrus W., 181. Macadam roads, 160; bitumi- nous, 163. Machine, defined, 186; ele- ments of, 186. Machine shed, 473. Machinery, farm, 180; binder, 239; care of, 309; corn harvester, 252 ; corn shellers, 299; definitions and princi- ples, 186; elevators, 287; ensilage, 273; fanning mills, 282; feed mills, 298; hay, 258; influence of, 181; in- troduction of, 180; manure spreaders, 292; motors, 313: threshing, 278 ; spraying, 303; windmills, 339. Magnetos, 358. Manure spreaders, 292. Malleable iron, for machines, 197. Maps, contour, 52; final, 70; preliminary survey, 66. Map making, 28. Maple wood, qualities of, 196. Markets, influenced by roads, 143. Materials, mechanics of, 402, 406; used in machinery, 195. Measurement of power, 316; of water, 134. Measuring, 18; instruments for, 20; tables for, 19. Mechanics, defined, 15. Mechanics of materials, 402, 406. Meridian, guide, 39; principal, 38. Metes and bounds, surveys by, 40. Modulus of rupture, 408. Modulus of section, 407. Moment of a force, 402. Monuments, 40. Motors, classification of, 344; farm, 313; horses as, 327. Mowers, 258; adjustment, 262; construction, 258; size, 258; types, 258. Newbold, Chas., 180. Notes, field, 24, 50. Oak, as material for machines, 196. Oil cups, 192. Open ditches, 103; capacity of, 104; construction of, 103; cost of, 104; disadvantages of, 104. Orchard irrigation, 121. Pacing, 23. Perry pneumatic water supply system, 495. Pine, for machines, 196. Pipes, water, 491; flow of wa- ter in, 492; sizes, 491; sys- tems, 492. Plank frame for barns, 445. Planter, corn, 231. Plastering, 458. 552 INDEX Plows, 199; adjustment, 200; construction, 200; disk, 204; draft of, 204; engine gang, 208; gang, 201; harrow at- tachment for, 219; hillside, 207; selection of, 199; size, 199; sulky, 201; types of, 199. Plumb line, 43. Plumbing, for houses, 497; fix- tures, 497. Plungers, for pumps, 489. Poncelet's formula, 79. Population on farms, 183. Poplar wood, qualities and uses, 196. Potatoes under irrigation, 120. Poultry houses, 425 ; construc- tion details, 426'; location, 425; size, 425; types, 432. Power, defined, 314; for light- ing plant, 521; for pumping, 486; from horses, 327; meas- urement of, 316; required for machinery, 361; trans- mission of, 320. Power mills, 298, 340. Preliminary survey, 64. Pressure gauge, 381. Prime movers, 313. Profile, leveling, 49; grade, 74. Prony break, 316. Pumps, 487; important fea- tures of, 488. Pumping plant, 486. Pumpinng water, cost of with engine, 363; for irrigation, 125. Pulleys, 322; calculating speed of, 323. Purlines, 445. Pulverizers, 221. Quadrants, for transmitting power, 324. Radiation, estimating, 529. Radiators, 526, 529. Rakes, sweep, 268; sulky, 259; side delivery, 260. Range of townships, 39. Range pole, 21. Rating, of tractors, 392. Rectangle, area of, 34. Reinforcement of concrete, 412. Repair of machinery, 309. Reservoirs, for irrigation, 123; home water supply, 493. Resultant, defined, 314. Resurveys, 40. Reversible plow, 207. Road drag, 150, 173. Road grader, 97; elevating, 169; scraping, 168. Road machinery, 167; classes, 167; scrapers, 167. Roads, 141; benefits of good, 142; brick, 165; clay, 153; earth, 147; extent of, 141; gravel, 154; history of, 14; requisites of good, 145; sand, 153; sand-clay, 153; scrapers for, 167; stone, 160. Road rollers, 170. Road stone, 160; testing, 161. Rock crushers, 172. Roller bearings, 191. Rollers, for roads, horse, 170; land, 220; power, 171; tan- dem, 171. Rope transmission, 323. Round barns, 449. Rubber belting, 321. Run-off, computing, 80. Safety valve, 381. Sand, for building, 411. Sand-clay roads, 153. Sand roads, 153. Sanitation, 480. Scrapers, for disk harrows, 218: road, 167. Sections of townships, 39. INDEX 553 Seeders, end gate, 224; hand, 223; seed-box broadcast, 224; utility of, 223; wheelbarrow, 224. Self-aligning bearing, 190. Septic tank, 501; construction of, 504. Sewage disposal, principles of, 502; by irrigation, 114, 138; systems of, 501. Shafting, 325. Shawver barn frame, 446, 448. Sherringham valve, 534. Shredders, 256. Shop, farm., 477. Side draft, overcoming, 337. Silos, 461; essentials, 463; lo- cation, 461; masonry, 468; size, 461; wood, 465. Silt basins, 99. Sled corn cutters, 251. Slings, hay, 271. Soils, improved by drainage, 61; kinds of, 59. Splices, 543. Spraying machinery, 303. Spraying method of irrigation, 134. Springs, as water supply, 483. Spring-tooth harrow, 213. Stackers, hay, 269; straw, 280. Stalls, cow, 440; horse, 443. Standard of purity of air, 531. State Highway Commission, 178. Statics defined, 402. Steam boiler, 376; accessories, 380; capacity of, 379; func- tions of, 377; management, 388; principle of, 376; types, 377. Steam engines, 376, 385; kinds. 386; principle of, 385. Steam, formation, 377; quality of, 380. Steel, Bessemer, 197; cast, 197; mild, 197; soft center, 198; tool, 198. Stone, building, 409. Stone roads, 160; construction of, 162; cost of, 165; main- tenance of, 165. Stoves, 525. Strength of materials, 402, 406. Stress, defined, 403; kinds of, 403. Subirrigation, 133. Subsurface packer, 220. Suction of plows, 200. Sugar beets under irrigation, 120. Sulky plows, 201; adjustments of, 203. Sunlight as a sanitary agent, 506. Surface measure, 19. Survey, defined, 16; prelimi- nary, 64. Surveying, agricultural, 16; divisions of, 17; problems, 26. Surveyor's measure, 20; uses of, 16. Sweep rakes, 268. Tanks, water, 493. Tapes, 20; care and use of, 22. Teams, size of, 329. Tedder, hay, 267. Telford roads, 160. Temperature system of ventila- tion, 534. Tests, of concrete, 411; engines, 316, 36"6; horse, 328. Threshing machinery, 278. Tile, blinding, 94; cement, 92; inspection of, 94; laying, 92; roots of trees in, 100; select- ing, 91. Tile drains, capacity of, 78; cause of flow in, 78; construc- tion of, 96; cost of, 101; depth, 67; digging ditches, 86; distance apart, 68; filling, 96; outlet of, 98; size of lat- erals, 84 ; staking out, 71 ; systems of, 69. 554 • INDEX Tongue truck, 338; for harrows, 218. Tool, denned, 186. Tool shop, 477. Topographical signs, 31. Towers, water, 493; windmill, 342. Township, division and num- bering, 38; sections of, 39. Traces, proper angle of, 331. Tracks, hay, 272. Tractor, steam, 389. Transit, 54. Transmission of power, 320. Transportation, cost of, 142. Transport truck, 219. Trapezium, area of, 35. Trapezoid, area of, 35. Ti-iangles, area of, 34; trans- mission of power by, 324. Trucks, transport, 219. Turning point, 52. Ultimate strength of materials. 404. Underdrainage, 59. United States system of land survey, 38. Valve action in oil engines, 359. Valves, for pumps, 489; safety, 381. Ventilation of farm buildings, 531; influence of wind, 533; mechanical, 535; purposes of, 31; temperature system, 534. Ventilator, cloth curtain, 533. Vertical boiler, 377. Wages, influence of farm ma- chinery on, 182. Warm-air furnace, 526. Waste bank, 104. Water, capillary, 57; control of, 111; duty of, 56; hydrostatic, 57; measurement of, 134; reg- ulation of soil water, 56; re- quired for crops, 115; used in irrigation, 117. Water level, 43; laying tile by, 89. Water pipe, 491; flow of water in, 491; sizes, 491; systems, 492. Water supply, 480. Water wheels, 487. Weigher, 280. Weir, 134. Wells, 480. Whipping a rope, 541. Windmills, 339; construction, 341; development, 339; power of, 341; regulation, 341; size of, 340; towers, 342; types of, 340; utility of, 339, 486. Windows, design of, 5'08; loca- tion of, 507; size of, 508. Wing joist barn frame, 446. Wire rope transmission, 324. Wood, as a material for ma- chines, 195. Work, defined, 186, 314. Working stress, defined, 404. Wrought iron, 197. Wye level, 46. Agricultural Text Books FOR HIGH SCHOOLS Published by WEBB PUBLISHING CO., ST. PAUL, MINN. This series of agricultural books, of which Agricultural Engineering is a representative, is planned especially for high schools in which agriculture is taught. The books constitute a complete four-year graded course in agriculture. Each book is complete in itself, and its scope is well within the limits of the course. They are written by men eminent in their line, and who are well known for their clear and concise presentation of facts. Each of the books listed below has suggestive subjects for discussion and demonstration at the close of each chapter. The series constitutes a complete, concise, and practical course that will meet the urgent needs of the modern agricultural high schools and of short courses in schools and colleges. FIELD CROPS By A. D. WILSON, Sup't of Farmers' Institutes and Exten- sion, Minnesota College of Agriculture, and C. W. WARBURTON, Agronomist, U. S. Dep't of Agriculture. 544 pages, 162 illustrations, cloth, $1.50 net. The aim of this book is to present the peculiarities of each of the various classes and varieties of farm crops, the handling of the soil, selections of seed, and general crop management. The book covers the cereals, including corn, wheat, oats, rye, barley, etc.; forage crops, including hay grasses, clover, alfalfa, cowpeas and other legumes; how to make good meadows and pastures, and the art of hay making, etc.; root crops; sugar crops; fiber crops, including cotton, flax, hemp; tobacco, potatoes, in fact every farm crop of any importance is dis- cussed. The introductory chapters are devoted to the general classi- fication of farm crops and their uses and relative importance, and reviews the subject of how plants grow. The concluding chapters discuss the theory and practice of crop rotation and weeds and their eradication. A list of the best supplementary reading, including farmers' bulletins, is given at the close of each chapter. The style is easy, subject matter well arranged and vital, and the book is of excel- lent mechanical makeup throughout. BEGINNINGS IN ANIMAL HUSBANDRY By CHARLES S. PLUMB, Professor of Animal Husbandry, College of Agriculture, Ohio State University. 395 pages, 217 illustrations, cloth, $1.25 net. Beginnings in Animal Husbandry is the only book published that is specially designed to meet the needs of students in Animal Husbandry courses in secondary schools. Among the subjects discussed are: The Importance of Animal Husbandry; Breeds of Horses, Cattle, Sheep and Swine; Animal Type and Its Importance; Reasons and Methods in Judging Live Stock; Points of the Horse; Judging Horses, Cattle, Sheep and Swine, etc.; Heredity: Its Meaning and Influence; Selection and Its Importance; Pedigrees and Their Values; Suggestions to Young Breeders; Composition of Plants and Animals; Influence of Foods on the Body; Feeding Standards, Origin and Use; How to Calculate a Ration; Coarse Feeds and Their Values; Concentrated Feeds and Their Value; Care of Farm Animals; Poultry: Types and Breeds, Judging, Feeding; Eggs and Incubation; Poultry Houses. Topics for discus- sion and suggestions for observation and application are included at the close of each chapter. SOILS AND SOIL FERTILITY By A. R. WHITSON, Professor of Soils and Drainage, and H. WALSTER, Instructor in Soils, of the University of Wisconsin. 315 pages, well illustrated, cloth, $1.25 net. No other book on Soils presents the relation of the soil to the production of crops in so clear and agreeable a manner as this. There are chapters on the following: Conditions Essential to Plant Growth, Origin and Classification' of Soils; Primary Relations of Soil and Plant; Nitrogen; Phosphorus and Potash; Soil Analysis; Farm Manure; Com- mercial Fertilizers; Physical Properties of Soils; Water Supply; Tem- perature and Ventilation of Soils; Drainage; Erosion; Tillage; Humus; Relation of Crops to Climate and Soil; Soils of the United States; Management of Important Types of Soil; Dry Farming. Explicit language and the avoidance of technical matter make the book ideal for beginners in this subject. A well-chosen set of fundamental labora- tory exercises and demonstrations, with complete directions, is included. POPULAR FRUIT GROWING By SAMUEL B. GREEN, late Professor of Horticulture and Forestry, University of Minnesota. 300 pages, 120 illustrations, cloth, $1.00 postpaid. This book covers the factors of successful Fruit Growing, with lists of fruits adapted to each state; Orchard Protection; Injurious Insects and Diseases; Spraying; Harvesting and Marketing Methods; Propagation of Fruits; etc. A very popular book for schools and col- leges. A new, revised edition by Le Roy Cady, Professor of Horticul- ture, University of Minnesota, is just out. VEGETABLE GARDENING By SAMUEL B. GREEN, late Professor of Horticulture and Forestry, University of Minnesota. 252 pages, profusely illustrated, cloth, $1.00, postpaid. A manual on the growing of vegetables for home use and for the market. The immense sale of this book to farmers and gardeners, and its wide adoption for class-room work in agricultural schools and col- leges, prove it to be the standard work published on this subject. This is the 12th revised edition. We have a paper covered edition of this book which sells for 50c. DAIRY LABORATORY GUIDE By G. L. MARTIN, Professor of Dairying, North Dakota Agricultural College. 140 pages, illustrated, cloth, 50c. postpaid. This laboratory manual offers a carefully organized series of exer- cises covering the principles of modern dairy practice, with sugges- tions for their practical application. It covers the Production and Care, Testing, Manufacture, and Marketing, of Dairy Products. An indis- pensable guide for classes in Dairying and for Creamerymen. SILOS: CONSTRUCTION AND SERVICE By M. L. KING, formerly Silo Expert, Iowa State College, and Orig- inator of the Iowa Silo. 100 pages, well illustrated, cloth, 50c. postpaid. There is no recent American book on silo building, and none of any date that covers the many types of silos now in use and gives details of their construction. Mr. King here presents to the intended builder the principles of silo construction, and the advantages and dis- advantages of each type; but more particularly he gives the actual method of construction, with the main points of silo management. RULES OF ORDER FOR EVERY DAY USE AND CIVIL GOVERNMENT MADE PLAIN By HENRY SLADE GOFF, Author of the Goff's Historical Maps. 113 pages, illustrated, cloth, 50c, postpaid. There has long been a demand for an accurate Rules of Order text that was brief yet sufficiently complete for all practical needs. This is such a book. The matter is so clear, so well arranged, and so suc- cinct that those interested in social centers, clubs, societies, etc., will be delighted with it. The book also presents the main points of civil government that everyone ought to know. OTHER STANDARD AGRICULTURAL BOOKS AGRICULTURE FOR YOUNG FOLKS By A. D. WILSON and E. W. WILSON. A thoroughly practical treatise on Elementary Agriculture dealing with the every-day problems of the farm. This book avoids the vague generalities and scientific theories and treats each subject, in a manner easily understood and readily applied to existing conditions on every farm. Prepared especially for beginners and contains many valuable suggestions which would prove interesting to the most experienced farm manager. Among the numer- ous subjects discussed are: Preparing the Soil; Seeding; Rotation; Care of Crops; Marketing; Farm Business; Management of Cattle; Roads; etc., etc. Over 300 pages profusely illustrated. Price, $1.00 postpaid. AMATEUR FRUIT GROWING, by Samuel B. Green. A practical guide to the growing of fruit for home use and the market, written with special reference to cold climates. Illustrated. 134 pp. Price, 12 mo. paper, 25 cents; cloth, 50 cents. ELEMENTS OF AGRICULTURE, by H. J. Shepperd and J. C. McDowell: A complete treatise on practical agriculture, covering plant and animal breeding; thoroughly illustrated. A complete text book, adopted in public and agricultural schools throughout the Northwest. 12 mo., cloth, 100 pp. Price, $1.00. WEEDS AND HOW TO ERADICATE THEM, by Thomas Shaw, giving the names of the most troublesome weed pests east and west and successful methods of destroying them. Price, 16 mo., 210 pp., cloth, 50 cents; paper, 25 cents. FARM BLACKSMITHING. A complete treatise on black- smithing by J. M. Drew. Written for farmers who want a workshop where they can profitably spend stormy days. Illustrated, 100 pp. Price, 12 mo., cloth, 50 cents. STANDARD BLACKSMITHING, HORSESHOEING AND WAGON MAKING, by J. G. Holmstrom, author of "Modern Black- smithing, " gives practical instructions by a successful blacksmith. The latest and most complete book on the subject published. Thoroughly illustrated. Price, 12 mo., cloth, $1.00. GRASSES AND HOW TO GROW THEM, by Thomas Shaw. Discusses the economic grasses fo the United States and Canada from the standpoint of the farmer and the stockmen. Price, 450 pages, cloth, $1.50 postpaid. WEBB PUBLISHING CO. . ST. PAUL, MINN. ■'/. ' • 1 1 - N* s • • / * - - U I 4 ^ It. * a i \ '" *' / V. LIBRARY OF CONGRESS Q0DE757E3^A