DEPARTMENT OF THE INTERIOR, CANADA FORESTRY BRANCH t-NRLF B 3 372 7flfl METHODS OF COMMUNICATION ill ADAPTED TO FOREST PROTECTION OTTAWA THOMAS MULVEY PRINTER TO THE KING'S MOST EXCELLENT MAJESTY 1920 Price, $1.00. i. • Forestry - Main Library DEPARTMENT OF THE INTERIOR, CANADA FORESTRY BRANCH METHODS OF COMMUNICATION ADAPTED TO FOREST PROTECTION BY W. N. MILLAR, B.S, M.F, M OTTAWA THOMAS MULVEY PRINTER TO THE KING'S MOST EXCELLENT MAJESTY 1920. 79211— A n . - Forestry - Main Library The methods of forest telephone eC'riotraeision' describVd in this manual have been adopted almost without change from the " Instructions for Forest Officers " as issued by the United States Forest Service, Department of Agriculture, in its publication entitled " Telephone Construction and Maintenance OTI the National Forests." With the permission of the Forest Service a considerable portion of these instructions has been reprinted herein and forms the bulk of Chapters VII, VIII, IX, XI, XII, and XVI, as well as parts of other chapters. Most of the diagrams illustrating telephone construction methods are also reproduced from the same publication. A few were adapted from a special circular of instructions prepared by the District Forester, District 5, United States Forest 'Service and certain material in the text was secured from the same circular. Other important publications from which material has been derived are the following: "Systematic Fire Protection in the California Forests," Dubois; "Fire Protection in District 1," Silcox; "Manual of Visual Signalling," United States Signal Corps; " Trailing Manual— Signalling 1915," British War Office. In only a few cases, however, has it been possible to quote. In addition, a large number of works on special phases of the subject have been consulted and these are for the most part included in Appendix B. Persoiial assistance of the greatest value has also been received from Mr. E. H. Finlayson, District Inspector of Forest Reserves for Alberta, who has aided in the determination of the general plan of the manual and has particularly assisted by criticism of Chapter XIV; from Mr. R. B. Adams, Telephone Engineer, United States Forest Service, Missoula, Montana, who has offered many valuable suggestions and furnished much of the material contained in Chapters X and XIII; from Mr. J. B. Somers, United States Forest Service, in connection with the use of the heliograph and flag by the Service, and from many field officers of the United States Forest Service and the Dominion Forestry Branch with whom the author has been associated in forest administration. 79211— A! ABBKEVIATIONS A. W. G.=American Wire Gauge (Brown & Sharpe) B. B. = Best Best iron wire B. & S. = Brown & Sharpe wire gauge B. I. G. = British Imperial Gauge B. S. M. G. = Birmingham Sheet Metal Gauge B. W. G. = Birmingham Wire Gauge D. B. = Double-Bitted, as of an axe D. F. B- = Dominion Forestry Branch E. B. B. = Extra Best Best iron wire E. M. F. = Electro-Motive Force N. B. S. G. =New British Standard Gauge S. B. = Single-Bitted, as of an axe U. S. S. M. G. = United States 'Sheet Metal Gauge IV CONTENTS % Page Introduction XV Part I — Communication in Specialized Forest Protection CHAPTER I — SPECIALIZED FOREST PROTECTION. Sec. 1 Specialization Defined 1 2 Communication Defined '.'. . 2 3 Present Protection Methods 2 4 Analogy to Military Operations 3 5 Functions of a Forest Protection Force 3 6 Prevention of Forest Fires 4 7 Detection of Forest Fires 5 8 Suppression of Forest Fires 7 9 Supervision of Protection Forces 8 10 Duties of Supervising Officers 8 11 Duties of Suppression Staff Officers '...''.. 10 12 Duties of Suppression Line Officers. 12 13 Value of Communication System in Field Operation 13 CHAPTER II — METHODS OF CONVEYING INFORMATION TO A DISTANCE. 14 Variety of Methods Available -..'•• 14 15 Types of Visual Signals 14 16 Types of Audible Signals >•'''•• 15 CHAPTER III — ADAPTING COMMUNICATION METHODS TO SPECIALIZED FOREST PROTECTION 17 Speed and Certainty in 'Communication Essential 17 18 Method Must be Adapted to Conditions of Use 17 19 Control Units Requiring Intercommunication Facilities 17 20 Communication Requirements of Control Units. . 19 21 Superiority of the Telephone Evident. .'....' 20 22 Auxiliary .Methods Often Required 20 Part II— Forest Protection Telephone Lines CHAPTER IV — PLANNING THE TELEPHONE SYSTEM « 23 Importance of Preliminary Plans 23 24 Plans Must Be Based on Definite Area 23 25 Primary Stations Requiring Service 23 26 External Versus Internal Systems 24 27 Connections to Lookout Stations 26 28 Test Stations 26 29 Relay Stations 26 30 Alternative Routes 26 31 Secondary Strategic Points • 27 v vi METHODS OF COMMUNICATION FOR FOREST PROTECTION CHAPTER V — SELECTING THE TYPE OF CONSTRUCTION Sec. Page 32 Pole-line 'Construction 27 33 Tree-line Construction 27 34 Construction Methods Contrasted 28 35 Relative Cost of Different Types 28 36 Sketch of the Development oi Tree-line Methods 29 37 Influence of Timber Conditions on Choice -of Construction Type 30 38 Grounded Versus Metallic Circuits 32 CHAPTER VI— TELEPHONE CONSTRUCTION POLICY IN DOMINION FOREST EESERVES 39 Construction by the Forestry Branch 33 40 Co-operative and Private Lines 33 41 Use of Forestry Branch Lines 34 42 Telephone Improvement Plans 35 43 Standard Methods 35 44 Standard Materials 36 CHAPTER VII — OPERATIONS PRELIMINARY TO CONSTRUCTION 45 Factors Influencing Location 42 46 Survey of Route 42 47 Securing Right of Way 42 48 Clearing Right of Way 41 49 Transportation and Distribution of Materials 45 50 Organization and Equipment otf Construction Crews. 46 CHAPTER VIII — POLE-LINE CONSTRUCTION 51 Selection of Poles 47 52 Skidding and Seasoning. . 47 53 Preservative Treatment 47 54 Length of Poles 49 55 Erection of Poles 49 56 Bracing and Guying . .. 54 57 Line Construction 59 CHAPTER IX — TREE-LINE CONSTRUCTION 58 General Principles 68 59 Selecting Trees .and Route t 68 60 Line Construction 69 CHAPTER X — EMERGENCY LINES, CONSTRUCTION AND USE 61 Use in Forest Protection 74 62 Line Construction 74 63 .Maintenance. 76 14 Taking up Wire 76 CHAPTER XI — FOREIGN LINES, CROSSINGS, AND CONNECTIONS 65 Location on Poles of Foreign Lines 78 66 Crossings .. 78 67 Connecting Forestry Branch Lines with Private Lines or Exchanges. ... 82 68 Branch Lines.. 8° CONTENTS „ vii CHAPTER XII — INSTALLATION OF FIXED EQUIPMENT Sec. Page 69 Wall Sets : 85 70 Condensers 85 71 Dry Batteries 85 72 Protectors 88 73 " Grounds " 90 74 Wiring 92 75 Lookout Station Telephone Sets . . . 94 76 Howler and Condenser for Vibratory Signalling 96 77 Coils .. .. 98 78 Special Installations 99 CHAPTER XIII — INSTALLATION OF TEMPORARY EQUIPMENT 79 Types of Portable 'Sets 107 80 Forestry Branch Portable Telephone 108 81 Adams Hand Set 110 82 Emergency Communication Kits 114 83 Temporary Connection to Permanent Lines 115 CHAPTER XIV — MAGNETO TELEPHONE 84 Introduction 117 85 Definition of Electrical Terms 118 86 Parts of the Magneto Telephone 121 87 Methods of Connecting Telephones to Line 137 CHAPTER XV — OPERATION 88 Operating Rules 140 89 Code Signalling 140 CHAPTER XVI — MAINTENANCE 90 General Principles 142 91 Line 142 92 Apparatus 145 93 " Trouble " 152 CHAPTER XVII — TELEPHONE " DON'TS " 94 Construction 157 95 Installation 158 96 Operation 158 97 Maintenance. . . 159 Part III— Forest Protection Heliographs and other Signalling Apparatus CHAPTER XVIII — HELIOGRAPH 98 The Instrument 160 99 Use in Forest Protection 160 ICO Range and Speed 161 101 Types of Heliographs 162 102 Heliographs at Lookout Stations 165 103 Heliographs on Patrol Routes 109 viii METHODS OF COMMUNICATION FOR FOREST PROTECTION CHAPTER XIX — USE OF THE GODWIN HELIOGRAPH Sec. Page 104 Parts of the Instrument 169 105 Using the Godwin Heliograph ' .. 170 CHAPTER XX — SIGNALLING WITH THE HELIOGRAPH 100 Selecting a Station 173 107 Position of Operator 173 108 Maintenance of Adjustment 174 109 Opening Communication 174 110 Working at Short Ranges 175 111 Working Through Haze and Smoke 175 112 Heliograph Codes 175 113 Instructions to Operators 179 114 Care of Instruments . . 180 115 Training Operators 180 116 Heliographing by Moonlight and Artificial Light 181 CHAPTER XXI — NIGHT SIGNALLING 117 Signalling Lanterns 182 CHAPTER XXII — FLAG 118 General Remarks 186 119 Equipment Required 186 120 Range and Speed 186 121 Use in Forest Protection 187 CHAPTER XXIII — USING THE FLAG 122 General Remarks . . 188 123 Selecting a Station 188 124 Wigwag Signalling 189 125 Rules for Operators and Conventional Signals 191 126 Wigwag Codes 191 127 Semaphore Signalling 191 CHAPTER XXIY — MESSAGE CODES 128 Purpose oi Codes 194 129 Use in Forest Protection \ 194 130 Combinations Available 194 CHAPTER XXY — DANGER SIGNALS 131 Risk in Fire-fighting 195 132 Use of Danger Signals 195 133 Code of Danger Signals 195 134 Miscellaneous Uses of Shot and Whistle Signals 196 CONTENTS Appendices APPENDIX A — OUTFIT FOR TELEPHONE CONSTRUCTION CREW Page 1 Ten-man Crew for Telephone Construction 196 2 List of Line Supplies 197 3 List of Station Supplies 197 4 List of Construction Tools 197 5 List of Tentage .. 198 6 List of PTOvisions 198 7 List of Kitchen Equipment 198 APPENDIX B — USEFUL BOOKS OF EEFERENCE 1 Science of Telephony 199 2 Line Construction 199 3 Preparation and Preservation of Poles 200 4 Military Signalling and Telephony 200 5 Telephone Troubles 200 6 Specialized Forest Protection 200 7 Periodicals 201 8 Trade Catalogues and Handbooks 201 APPENDIX C — TELEPHONE COSTS 1 Factors Involved i-n the Estimation oif Costs of Pole and Tree Telephone Lines 201 2 Approximate Costs of Supplies and Average Time Required for Various Operations in Telephone Line Construction 202 APPENDIX D — EULES FOR WIRES CROSSING EAILWAYS AND TRANSMISSION LINES Order No. 231 Board of Railway Commissioners of Canada 203 APPENDIX E — FORESTRY BRANCH STANDARD SPECIFICATIONS 1 Specification's for Galvanizing 209 2 Specifications for Gal van izedr iron Telephone Wire 210 3 Specifications for Hard-drawn Copper Telephone Wire 211 4 Specifications for Emergency Wire 211 5 Specifications for Rubber-covered Wire. 212 6 Specifications for Glass Insulators 213 7 Specifications for Split Tree Insulators 214 8 Specifications for Poles 215 9 Specifications for Wooden Spools 'for Emergency Wire 217 10 Specifications for Creosote 217 11 Specifications for Wooden Brackets 218 12 Specifications 'for Outdoor Protector Mounting-boxes 219 APPENDIX F — SOLDERING Methods and Materials.. 219 METHODS OF COMMUNICATION FOR FOREST PROTECTION APPENDIX G — USEFUL TABLES. Page 1 Weight of Cedar Poles of Various Lengths and Top Diameters 221 2 Number of Poles of Different Sizes Required to Make up a Carload Lot. . 221 3 Comparison of Wire Gauges 222 4 Tensile Strength of Bare Copper Wire 223 5 Properties of Hard-dra'wn Copper Telephone and Telegraph Wire 223 6 Properties of Bimetallic Wire 224 7 Properties of Galvanized Telephone and Telegraph Wire 224 8 Properties of Galvanized Steel Wire 225 9 Properties, of Rubber-covered, Lead-incased Copper Cables 225 10 Properties of Standard Wire for Telephone Construction on Dominion Forest Reserves 226 Index 227 CONTENTS Xi Illustrations Fig. . Page 1 Lookout station on a Dominion forest reserve in British Columbia 5 2 Steel lookout tower on a Dominion forest reserve in Saskatchewan 6 3 External telephone system on a forest reserve 24 4 Internal telephone system on a forest reserve 25 5 Mobley wire-CTadle as used with two coils 43 6 Mobley wire-cradle as us-ed with one coil 43 7 Mobley wire-cradle . . 44 8 Klondike pack-.frame as used for packing wire 4o 9 Pole-steps 51 10 Location of brackets on pole 51 11 Definition of rake 53 12 Definition of pull 53 13 Setting a pole. 54 14 Method of bracing 55 15 Method of guying , 56 16 Kc-ck guy bolt 57 17 Method of using guy stub 58 18 Method of ground bracing 58 19 Tripod line .supports 59 20 Home-made reel 61 21 Transposition of wires, metallic circuit 62 22 Method oi making regular tie for iron wire 64 23 Method of making " figure 8 " tie for iron wire. 64 24 Method of dead-ending iron wire 65 25 Method of dead-ending hard-drawn copper wire 65 26 Method of making regular tie for hard-drawn copper wire 66 27 Method of making " figure 8 " tie for hard-drawn copper wire 67 28 Method of splicing iron wire (Western Union joint) 67 29 Method of splicing 'hard-drawn copper wire 67 30 Zigzag system of alignment. 69 31 Reverse curve system of alignment 69 32 Split tree insulator attachment and cmsstie ". . . . 71 33 Method of dead-ending on tree lines . . . . 72 34 Method of tying up emergency wire 75 35 Method of making temporary splice in emergency wire 77 36 Emergency wire reel, open and folded 77 37 Method of crossing transmission lines 79 38 Method of connecting branch line to main line when both are galvanised- iron wire 82 39 Method of connecting branch line to main line 'when both are hard-drawn copper wire 83 40 Method of connecting branch line to main line in tree construction. ... 84 41 Wiring diagram of standard wall set 86 42 Standard telephone installation 87 43 Method of connecting dry cells for a telephone. 87 44 Method of installing line fuse when required 88 45 Wiring diagram for telephone station 90 xii METHODS OF COM MUNI CATION FOR FOREST PROTECTION Fig. Page 46 Method of making entry to building from main line 93 47 Wiring diagram of lookout station telephone set. 95 48 Lookout station telephone set installed in the field 96 49 Method of connecting lookout station telephone to line and ground 97 50 Method of connecting howler ,and condenser • 98 51 Method of installing lavite coil to drain line of static electricity 99 52 Method of installing a repeating coil on a pole 100 53 Legend 101 54 Switching station, first method 102 55 Switching station, second method 102 56 Wiring -and connections on 47^A repeating coil.. .... .. 103 57 Phantom circuit 104 58 Connecting grounded line to metallic line through a repeating coil without switches . . . 105 59 Connecting grounded line to metallic line by use of switches and two telephones ..'.. .: . 105 60 Connecting grounded line to metallic line by use of switches and one telephone . 106 61 Method of using one wire for simultaneous telegraphy and telephony. . . . 107 62 Forestry Branch portable telephone set (1375-A) 109 63 Wiring diagram of Forestry B-ranch portable telephone ........ 110 64 Adams hand set (1004-A) with carrying case Ill 65 Wiring diagram of the Adams' hand set (1004-A) . . .'! . . . . Ill 66 Forest officer preparing to use the Adams hand set with Cree knife 'for ground rod . . ..:..:.... . . .... . . . . 113 67 Forestry Branch emergency communication kit No. 1-A. . .... ...... . . 114 68 Wiring diagram of No. 1-A kit .. .. .. '. .. •• 115 69 Forest ranger using the No. 1-A emergency kit • • • • • '•' '.'. . • • • • • • 116 70 Bipolar hand receiver .!'.... .\! .. ..'.... 122 71 Longitudinal section of bipolar .receiver.. .. .. .. .. ../.^.'. 122 72 Diagram of telephone circuit, first stage .... .... . . .... 122 73 Solid-back transmitter and transmitter arm. .'.' .. . . . . .'. . . . . . . 124 74 Details of the solid-back transmitter '. . . . . . . 124 75 Diagram of telephone circuit, second stage ". 124 76 Telephone induction coil 126 77 Diagram of telephone circuit, third stage. 1 . . 126 78 Magneto generator, five-bar 127 79 Polarized ringer, unbiased type 128 80 Telephone switch-hook -''.V ".;. ' Ci :!.' . "• • '...' • • 130 81 Rolled condenser . . . . . . . . 131 82 Howler . . . . 132 83 Lightning protector for use where there are no power ox light wires 133 84 Protector with fuses for use where there .are power or light wires 134 85 Baby knife-switches: (a) Single pole, single throw (S.P.S.T.) ; (b) Double pole, double throw (D.P.D.T.) 135 86 Method of inserting a metallic circuit section in a grounded line to overcome induction disturbances 136 87 Diagram of a phantom circuit . . . 136 88 Telephones connected1 in -.series on a metallic line . 138 89 Telephones connected in series on a grounded line. 138 90 Connecting bridging telephone on ,a grounded line 139 91 Connecting bridging telephone on a metallic line.. 139 92 Method of installing test station indoors 143 93 Method of installing a' test station on a tree. . . . 144 94 Stub reinforcement of poles 146 CONTENTS xiii Fig. Page 95 Receiver -test 148 96 Ringer of No. 127^F extension bell and Nos. 1317-P, 1317^8, 300-N, and 1336-J -telephones 151 97 Wiring of No. 1317 telephone set 153 98 British Army type of heliograph, one-mirror 162 99 British Army type of heliograph, two-mirror 16-3 100 American Army type of heliograph, one-mirror 164 101 American Army type of heliograph, two-mirror 164 102 Forest Service type of heliograph, one-mirror 166 103 Forest Service type of heliograph, two-mirror 167 104 Map of California national forest showing heliograph system 168 105 Forest ranger sending message by heliograph 171 106 Acetylene signal lantern with tripod 183 107 Fischer high-power electric signalling lamp 184 1 108 Initial position in flag signalling • 189 109 " Dot " or (motion " 1 " in flag signalling 190 110 " Dash " or motion " 2 " in flag signalling 190 111 Semaphore alphabet, numerals, and special signs 192 112 Two-arm fixed semaphore code 193 Design of Forestry Branch standard pony glass insulator 214 Design of Forestry Branch standard split tree insulator .. 215 Design of Forestry Branch standard emergency wire spool 217 Design of Forestry Branch standard wooden bracket 218 Design of outdoor protector mounting-box 219 INTRODUCTION This manual has a twofold purpose. Primarily, it is intended for the instruction and guidance of those officers of the Dominion Forestry Branch who are charged witj the protection of the forest reserves and other Dominion-owned timber and who find rapid and reliable means of communication an indispensable adjunct to their work. In order to fulfil this purpose, the various methods of communication which experience has demonstrated to be best adapted for use in forest protection are dealt with in detail, and the methods herein set forth are to be followed without deviation wherever permanent lines of communication are established. Particular attention is given to instructions for the building of forest telephone lines. In some important respects these lines possess unique characteristics. The distinctive requirements of telephone Communication for forest protection purposes have been the subject of much intensive study and experiment during the past decade both in Canada and the United States, and the equipment and methods of construction which have been adopted or developed have been standardized by the United States Forest Service and adopted by many state and private forest protection organizations in both countries. These standard methods with slight modification to fit Canadian conditions are set forth in detail in this manual and form the main body of the portion devoted to the telephone. It is felt, however, that information with regard to the usefulness of the telephone and other means of rapid communication in forest protection is of timely interest to all owners of timber in Canada. Thus far, there has been relatively little specialization in the work of forest protection on Canadian timber-lands. The usual system followed by both government and private owners has been to send out each year a large number of fire rangers, each of whom works on a more or less independent basis. In many cases a new crew is raised each year and in most cases dependence is placed on chance and the native ability of the rangers for the prevention, detection, and suppression of fires in their districts, without aid from special training, organization, or equipment. There are a few notable exceptions to this practice but as a general rule forest protection in Canada is handled by forces wholly lacking the training, organization, or equipment necessary for the employment of modern specialized methods and is, therefore, of necessity, costly and inefficient. One of the prime essentials in the organization of fire protection on a specialized basis, in contrast to the present non-specialized methods, is a reliable means of rapid communication linking up all strategic points within the forest with those outside of it and forming a network of lines of communication by which every unit of its protection staff is in constant touch with every other unit, and the whole is in direct communication with the chief ranger or other officer immediately responsible for the protection work on the area. In this manual, the principal means by which this inter- communication may be maintained in an unsettled timbered country are explained. Naturally, wherever adequate commercial telephone or telegraph services exist they will be employed, but these are of little importance in forest protection in Canadp because settlement in timbered regions is extremely meagre. xv xvi METHODS OF COMMUNICATION FOR FORREST PROTECTION Being intended for non-technical readers, it has been necessary in many instances to elaborate points that might otherwise have been passed over very briefly. For the same, reason a certain amount of repetition has been thought desirable. The aim has been to bring together in one publication not only the details of telephone construction and operation practice as exemplified on the Dominion forest reserves, but also all available information on various communication methods that have proved to be useful in connection with forest protection activities. It is believed that only one subject of importance has been given very inadequate treatment and that is the question of pole preservation. This, it is planned to treat in a supplementary publication when certain investigations now being conducted are completed. PART I COMMUNICATION IN SPECIALIZED FOREST PROTECTION CHAPTER I ; v: .^ •>« » ,». r SPECIALIZED FOREST PROTECTION '.' Section 1 — Specialization Defined- /A, i«. '>.? **'*>'•'•' *>•*'• As applied to forest protection, specialization involves two primary modifications of old style methods. These are, on the one hand, an extensive centralization of executive authority in the hands of certain field officers who are responsible for the protection of certain clearly defined forest tracts and, on the other hand, a classifi- cation of the duties of the field staff into certain well-defined functions and the assignment of special men to the performance of these special functions. This is best understood, perhaps, by comparing the actual organization of the old style forest protection staff with the modern specialized staff. In the more primitive of the former the staff consists of a number of district chiefs or inspectors each of whom is responsible for the general supervision of the patrol staff in a certain area. These inspectors are most likely permanent employees. Under each is a number of patrolmen or rangers, assigned either singly or in pairs, to a certain subdivision of the inspector's district, called as a rule a " beat." Each of these rangers is responsible for his own beat only and within that area he performs all the functions of the fire prevention staff. The district chief or inspector is required to keep moving from beat to beat principally for the purpose of ensuring that the rangers are in the areas assigned to them and are performing their duties. In addition, he, being a permanent employee and presumably more skilled in those duties than the temporary staff, can assist the latter by advice and instruction. This extremely simple form of organization has, however, only one point in its favour which is that it can be employed where the field staff is wholly untrained or unskilled in modern protection methods while no other form can be so employed. It is, therefore, particularly adapted to regions where the subordinate protection staff consists of extremely low-priced labour, as in India where natives are largely employed for this work. Where our own standards of wages prevail, such a system to be effective must be tremendously expensive. This is as inevitable in forest protection as it is in other forms of organized human activity such as manufacturing, transportation, or military affairs, from all of which in the modern world this system has long since disappeared. 'Contrasted with this method of protection are the various more or less elaborated systems of specialization that have been developed by the leaders in forest protection. These developments differ in no material respect from those that have taken place in other large-scale activity but, owing to the nature of the work, they have followed more closely the methods of organization employed in military operations rather than those of most industrial activities. The most striking characteristic of a specialized staff is that instead of being a constantly moving patrol, each man confined to a limited area within which he performs all functions, it becomes very largely a stationary staff, each member of which performs only one function but may extend his activities over a large number of the old-time beats. Thus, instead of each man being individually responsible for detecting fires, certain men are specially assigned to this work and are located permanently on prominent lookout peaks or towers; instead of each man being responsible for putting out such fires as occur, special men, selected, equipped,. 79211—1 1 2 METHODS OF COMMUNICATION FOR FOREST PROTECTION and located with this one end in view are placed at strategic points and are despatched only to such fires as are discovered by the lookout men; instead of each man getting in his own supplies for himself or a fire-fighting crew, a special man operating over a large area with suitable equipment and assistants takes care of all the supplies and transportation. In short, to establish a specialized forest protection staff means nothing more or less than the extension of division .of labour on the modern basis of function to the work of protecting forests from fire. Section 2 — Communication Defined ' ;W(Ken we : spp a£'; of ^communication in connection with forest protection we may have in mind one or thf> .other of two rather distinct concepts. On the one hand, communication' refers/to, the conveyance of materials or of men from one place to another. In this sense communication becomes a problem of transportation and lines of communication become roa«ds, railways, trails, etc. With this type of communi- cation, although it is of vast importance in forest protection, this manual is not concerned. Communication in the other sense means the conveyance of information from one place to another. Obviously this does not necessarily involve any transfer of material substance, and lines of communication become telephone or telegraph wires, wireless installations, or signals of an almost endless variety. In this sense, communication is one of the prime essentials in specialized forest protection. Without well-developed means of transmitting information rapidly between all the numerous elements of a specialized force it is wholly impracticable to employ the distinctive features of specialized organization, and entire responsibility for all lines of work must necessarily be left in the hands of the patrolman, the least trained, and most poorly paid and equipped man in the whole force. This is obviously inevitable, however, in the absence of lines of rapid communication. At the same time it must be kept in mind that forest telephones and other modern devices for securing intercommunication do not of themselves produce specialization in a forest protection staff, but are merely a necessary mechanical device through the use of which functional organization and centralized control are rendered feasible. Section 3 — Present Protection Methods It is well recognized in Canada that forests if they are to be kept from burning up must have some kind of systematic protection during that portion of the year generally referred to as the " fire season." The extent of protection attempted largely depends upon the enlightenment of the owner of the timber, the value placed upon it and the fire danger or risk. This last is an extremely complex element made up of several factors which vary with the season, the character of the forest, the local causes of fire, and other local conditions which tend to favour or to obstruct the protection work. It is equally well recognized in the forested regions of Canada that the only kind of protection that has even a remote chance of success is patrol by a force of specially employed fire rangers. The patrol of timber-lands has been a feature of fire .protection in certain parts of Canada for more than thirty years. In other parts it is only of recent origin, while very large areas in all parts of the country, bearing a young growth whose value and vital national importance are unrealized, are as yet wholly unprotected. A careful study of most of these patrol forces, however, reveals the fact that they are organized and operated on extremely individualistic lines. Some of the very largest operate almost without a directive staff and in no case has there as yet been developed a staff capable of making a close scientific study of this problem of fire protection, resolving it into its elements and building up on a basis of known .facts a business-like organization and mode of procedure. In almost every case a SPECIALIZED FOREST PROTECTION 3 forest protection force in Canada consists simply of an indefinite number of more or less qualified men hired each year for the fire season only, and sent into the woods with only the most meagre instructions. In general they are told to prevent or to detect and suppress, so far as possible, forest fires in a specified district. Between rangers even in adjoining districts there is little or no relationship. There is practically no- differentiation of duties and no guidance or supervision except a very occasional visit of inspection, primarily to determine that they are actually present in their district and are not employed at some other work. Even this is successful only to a very- limited extent because of the inherent difficulties of maintaining close personal super- vision over a force which of necessity is widely scattered over a vast area of undeveloped country. The total annual expenditure for forest protection by all agencies in Canada is probably not less than $1,500,000. Single agencies spend as much as $350,000 per annum and employ 800 to 1,000 men annually. The value of the resource protected is of immense importance to the nation since fully 65 per cent of the country is capable of producing no other form of useful commodity. This resource is the raw material for the second largest industry of Canada. From this may be gained some idea of the relative importance of a scientific study of the business of protecting forests from fire. Section 4 — Analogy to Military Operations It requires but little knowledge of the operations involved in forest protection under conditions existing in Canada to appreciate the striking resemblances which exist between this work and military operations on a large scale. It is noted at once that there exist the same problems of transportation, of commissary and supply, of scouting and reconnaissance, of intercommunication, of camp management, and the handling of men on the fire-line. Also there are frequently involved problems in field engineering, and in animal management. Further, it is readily possible to divide the actual process of placing a forest fire under control by frontal attack, flank- ing trenches, or back-fires into two main sets of operations, namely tactical and strategical. The present is perhaps an opportune time to point out the vital import- ance of organization and discipline, of special training for individual units, of perfect equipment, and of a skilled and scientific directive staff in military operations. Months, even years, are spent in training men for the least responsible of military positions and we know that an army without this highly perfected organization and equipment, no matter how individually excellent, is a pitiable thing before a modern military machine. It is little realized, however, that forest protection, which in all its essen- tial operations bears such a striking resemblance to military operations, is susceptible of just as intensive study and development and that an unspecialized fire-ranger staff is, in its own sphere, just as pitiable an object when compared to a highly specialized staff as is an untrained ill-equipped army when compared to our modern troops. As is well known, the extent and perfection of control maintained in modern military operations is largely the result on the one hand of the perfection of functional control secured through the General Staff and on the other of two elements of mechanical eouipment, the gasolene engine as applied to transportation, and the tele- phone and telegraph as employed in intercommunication. It is one of the aims of this manual to indicate how these same highly developed means of intercommunication may be applied at small expense to the operation of directing forest protection forces. Section 5 — Functions of a Forest Protection Force A careful analysis of the operations involved in the protection of forests from fire reveals the fact that a fire-control force exercises four principal functions. These may be called Prevention, Detection, Suppression, and Supervision. In an unspecial- 79211— H A METHODS OF COMMUNICATION FOR FOREST PROTECTION ized staff each member of the staff exercises all four functions. Naturally there is no organized staff so completely unspecialized that there is absolutely no differentiation of functions performed by different members, but nearly* all of the forest protection forces of Canada ave so little specialized that the overwhelming majority of the staff actually does have all these functions to perform. As in other industries so in forest protection, non-specialization means independence of action and lack of close co-opera- tion. Thus we find that practically all fire rangers employed in Canadian forests are independent units, each supreme in his own district, performing individually all functions of fire control, and neither assisting nor receiving assistance from any other unit. Where specialization has been adopted, however, the whole organization is radically different. Specialization is the basis of modern industry, and the gain in efficiency that resulted from the industrial revolution is no more striking than is the improvement that results from the adoption of similar specialization in forest protec- tion. Obviously, no other result could reasonably be anticipated. Specialization in forest protection is secured by employing separate units to perform each of the distinct functions revealed by the analysis of the operations of forest protection. It is neither possible, nor necessary, to differentiate functions absolutely in all cases, but instead of each member of the control force performing all functions each is given one as a primary function and exercises the others only to a very minor degree, if at all. Section 6 — Prevention of Forest Fires The function of Prevention, as the name would indicate, includes all those activities whose aim is to ensure that fires do not start in the forest. Statistics of the causes of forest fires, upon which all prevention plans must be based, show that for the eastern part of the country human agencies are responsible for at least 95 per cent of forest fires, while in the West about 80 per cent are thus caused. This difference is due to the lightning-caused fires which are relatively more numerous in the mountainous regions of the West. Fires due to human causes may be considered almost wholly preventable, and a forest protection staff must be prepared to make an exhaustive study of the causes of the fires with which it has to deal and to apply the necessary remedies. Prevention of forest fires involves a whole host of considera- tions mostly beyond the range of this discussion and even in actual application largely beyond the influence of the direct control forces in the woods. Certain preventive measures, however, belong primarily to the woods staff. Such, for instance, are advice and warning to forest travellers and tourists. This is of very great importance in many forested regions of Canad'a. A specialized forest protection force will have certain of its members specifically assigned to this duty wherever the directive staff determines, as a result of a careful study of fire records, that such preventive measures are needed. In maintaining this observation of tourists and other travellers a well- developed system of communication by which the patrol force is kept constantly informed of the entrance of parties into the forest and of their movements while there is of immense value. By means of it every person in the force is enabled to contribute indirectly to the prevention work and to assume this as a secondary function without in any way interfering with whatever happens to be his primary function. Similarly, the supervision of " clearing " fires employed! by settlers, an extremely frequent cause of disastrous forest fires, is preventive in nature, and many other activities of this kind must be provided for, according to local conditions. In all cases, however, it is necessary to emphasize that the fundamental basis for scientific and effective prevention work is an accurate knowledge of fire causes in any given region. This is best secured by rigid investigation of all fires that occur and the accumulation of statistics of causes over a period of years. SPECIALIZED FOREST PROTECTION 5 Section 7 — Detection of Forest Fires The method of performing the function of Detection has to some degree become a distinctive characteristic of a specialized staff. In the usual type of organization with little or no internal co-operation or interdependence of units, each ranger must depend upon himself alone to detect and locate all fires in his district. To accom- plish this he adopts various methods according to the nature of the country and forest, the causes of fires, and his own energy, experience, and ingenuity. To some extent he relies upon reports received from various volunteer sources, supplementing this with patrol of routes of travel, and1, if the region is favourable, with observations from commanding peaks, ridges, or even unusually tall trees. If he sights a smoke from a distance he can determine its location only by his knowledge of the country, aided by a map if he has one and knows how to use it. In most cases his determination is likely to be only a mere approximation and much time is lost in searching for the fire and making the exact location. This done, he must then undertake its suppres- Fig. 1 Lookout station on a Dominion forest reserve in British Columbia sion either alone or with such assistance, often inadequate, as he is able to summon to his aid. During the Suppression period, the protection of his district will most lively be left entirely to chance. The fatal weakness of this system is the slowness and uncertainty with which it operates. One of the most efficient fire-preventive organizations in the world has as its motto " Minutes Count " and nowhere in the course of a fire do they count more disastrously than in the first few hours. Prac- tically all forest fires start as mere sparks. A neglected or half-extinguished camp- fire, a carelessly dropped match, the spark from a pipe or an engine, or some other similar insignificant source gives rise to the great bulk of disastrous fires. At the start and for some little time afterward, according to the weather, the season, and other local conditions, all such fires are easily within the power of one man to extinguish. But as they increase in size they increase even more rapidly in intensity. What was at first only a spark soon becomes a conflagration which only a very large crew of mon can make headway against. The lesson, therefore, that every ranger 6 METHODS OF COMMUNICATION FOR FOREST PROTECTION has learned is that the way to prevent large fires is to extinguish them when they are small — an obvious lesson — the accomplishment of which task is the primary purpose of specialization in forest protection. There are in general but two ways to ensure that all fires will be extinguished in their incipiency. The one is to put in an overwhelming force and depend upon -weight of numbers and extremely small districts to ensure success. The possibilities •of this system are soon reached, owing to the prohibitive expense. The other system is to adopt specialization, to use fewer but more highly trained men, to co-ordinate -.their activities by organization and discipline and to assist them with every form of Fig. 2 Steel lookout tower on a Dominion forest reserve in Saskatchewan mechanical appliance that will multiply their individual effectiveness. Among these appliances modern means of intercommunication are of basic importance, and in no respect is this more evident than in specialized means of Detection. The function of Detection in a specialized staff is performed by units entirely distinct from the rest of the force. The nature of their duties is such that they can rarely perform any other duties even as a secondary function, and only in a very imperfect way can other units perform the function of Detection on a secondary basis. These units, charged specifically with the duty of detecting and locating fires, are known as " lookout men " and hundreds of them are employed in specialized forest SPECIALIZED FOREST PROTECTION 7 protection forces in the United States. They are a most picturesque unit, perform- ing a little-known but valuable service under most unusual and often trying con- ditions. For the most part lookout stations are established on the tops of prominent mountain peaks; mount Hood in the Cascades, mount Fairview in the Rockies, even the active volcano, Lassen peak, in northern California, and scores of other mountains throughout the Western States are used for lookout purposes. Several have also been established in British Columbia by both the Dominion and provincial forest services. In the Eastern States, notably in New England, a very extensive develop- ment of the lookout system has taken place. Practically the entire timbered area of these states, and large parts of many others as far west as Minnesota, are watched b," permanent lookout men throughout the fire season. The location and character of the lookout stations is determined by the nature of the topography. If suitable sharp-topped peaks are not available towers must be erected. Lookout towers as high as 150 ft. have been built but ordinarily the standard steel towers which run from 30 to 80 ft. high are satisfactory. Satisfactory lookout service in a specialized organization demands the continuous presence of the lookout man at his station throughout the daylight hours ssven days in the week. This can be accomplished only by making the lookout station and dwelling-house one and the same. Accordingly a type of building has been especially designed for this work which is so arranged that no matter where the lookout may be while in the station he can always have a clear and unobstructed view of the entire area for which he is responsible. His duty, therefore, is easily defined. It is to remain at his station continuously throughout the day and maintain a constant watch over the area within his range of vision, noting all indications of fire, determin- ing 1heir location ,and reporting immediately to the proper unit of the control force. For the purpose of aiding him to fulfil his function he is provided with 'certain mechanical devices. These include tinted glasses to protect his eyes and aid him to distinguish faint smoke at long range, field-glasses with which to examine suspicious- looking smudges, a special form of lookout map correctly oriented, a fire locator (or alidade) for determining the bearing of a smoke, and finally a telephone or other means of communication by which he may report without delay. Rapid means of communication are fundamental to successful lookout service. For this purpose the forest telephone is universally preferred', but other means are sometimes used for reasons of expediency and are nearly always maintained in order to guard against temporary isolation of the station should the telephone line be broken. Wherever a region is fully covered by lookout stations, the precise location of a fire within a distance of a fraction of a mile may be quickly secured by the simple process of intersecting from two or more stations. Where the fire is visible from only one station, other methods of location, slightly less exact, have been devised. Many difficulties in the establishment and maintenance of dwellings on the high peaks of the western mountains have been encountered and many ingenious devices resorted to in overcoming them which it is beyond the scope of this manual to discuss. Also, it is impossible to discuss the human factor in lookout service which is in itself an element of much importance. Section 8 — Suppression of Forest Fires A fire having been discovered and reported by the lookout man, the third element of the specialized staff is brought into action. This is the unit whose main function is Suppression. The title " smoke chaser " applied to this unit adequately indicates the nature of the service. The " smoke chaser " corresponds to the fireman of a city fire brigade. His duty is to remain within call of his telephone bell or other communicating apparatus and upon being advised of the location of a fire to proceed to it by the shortest route in the least possible time and to extinguish it. Here, 8 METHODS OF COMMUNICATION FOR FOREST PROTECTION again, minutes count and every possible measure is taken to see that none are lost. If he travels on foot, his pack is ready to be instantly shouldered. After careful study and experiment a " smoke chaser's " pack, containing all essentials for three days and the tools needed1 for fighting a fire, has been devised to weigh only 21 pounds. If he can use a horse, it stands ready saddled and bridled; if he travels by power boat, it floats at his dock fully equipped. His only duty is to leave instantly, get to the fire in the least possible time, and d"o everything in his power to put it under control. Section 9 — Supervision of Protection Forces The " smoke chaser," however, is only the first or skirmish line of defence. Back of him stands the whole organized control force, the entire man-power of the community where this system has been most highly developed. This brings up the fourth function, that of Supervision. For the successful operation of a specialized protective force it is essential that the function of Supervision be performed by a permanent staff. In order to provide year-long employment economically this staff must necessarily be incorporated in the organization which is concerned1 with the woods operations. Private owners can incorporate it in their logging crews; govern- ments, in the scaling or inspection staff. This is a particularly easy problem in Canada where logging is confined almost exclusively to the winter season and fire- ranging almost wholly to the season when logging ceases. Keeping in mind the military analogy already alluded to, it will be evident that the supervising staff is nothing more or less than a skeleton organization composed wholly of officers, which organization can be rounded into a complete defensive unit by calling upon a large body of assistants of various degrees of training, according to the necessities of the season. In a region where anything in the nature of permanent settlement is found, this training may, indeed, be carried to considerable lengths and the efficiency of the force greatly enhanced. It will be realized, however, in studying the details of forest protection work that it divides rather distinctly into two general classes. There is on the one hand the more strictly administrative duties which fall to the various supervising officers. These include the day-by-day supervision of the work of prevention and detection forces ; the inspection of field conditions ; study of fire conditions and labour supply ; preparation and revision of mobilization schemes; the supply of provisions to field forces ; direction of construction on improvement projects and various other activities not concerned with the actual process of fighting fires, but either preventive in character or in the nature of preparation for fighting fires that are anticipated. On the other hand there is the actual forest fire-fighting, mostly on a small scale in a smoothly running organization but sometimes on a very large scale and with crews of considerable size. This, too, will as a rule be under the direction of the same supervisory officer, although in some cases the actual executive work on the fire-line is placed in the hands of a fire-line foreman while the supervisory officers devote their attention to co-ordinating the various auxiliary services and determining the general strategy of the fire-control operations. Here is seen a distinct develop- ment of staff and line functions as will be hereinafter explained. Section 10 — Duties of Supervising Officers It will be readily apparent that the duties and responsibilities of the supervisory officer in a specialized staff are much more extensive and call for a far more careful training than those of any grade of employee in a non-specialized force, or even in the other units of his own organization. He must be more carefully selected, more highly trained, and, naturally, better paid. His duties in connection with fire preven- tion are as follows: — SPECIALIZED FOREST PROTECTION 9 v 1 — DIRECTOR OF PERMANENT FORCES The maintenance of supervisory control over the entire prevention, detection, and suppression staff regularly employed in his district is of first importance to the super- visory officer. To do this it is essential that he be able to maintain communication with all units of this staff. This is accomplished by the proper planning of the permanent lines of communication witihin the district and the skilful use of the portable and emergency equipment described in this manual. 2 — MOBILIZATION OF SUPPRESSION FORCES The supervising officer must organize and direct the mobilization of all the forces needed to form the main and supporting lines of defence in fire suppression. While the aim of specialized forest protection is always to handle all fires in the incipient stage this ideal cannot always be maintained, and through delays in detection or reporting, faulty location or other failures, some fires will prove too formidable for the "smoke chaser" alone. There are few forest regions even in the more remote parts of Canada's commercial timber-belt where there is not some form of local settlement. Where agri- cultural settlers are not found there are still logging camps, miners, construction crews, or perhaps surveyors, tourists, summer residents, hunters, etc. The communication system must be planned to put the supervising officer in direct touch with all these sources of labour and he must organize this labour so that in ease of emergency it may be called upon for assistance with a reasonable certainty of an immediate and effective response. This has been accomplished in several ways but probably the most successful has been through the organization of volunteer fire companies, organized with all the necessary officers and bound by agreement to report on call at designated points. Many factors and local conditions necessarily cause wide variations in the possibilities of developing these forces for use in fire emergencies. In the more highly perfected organizations it is possible to distinguish three lines of defence or classes of forces behind the "smoke chaser." These may be called: — (a) Main line forces, which are as .a rule made up of all the available employees of the timber-owner; (&) Supports, which consist of local residents usually scattered through or on the immediate borders of the forest who are under definite contract to perform certain specified emergency fire duties; and (c) The Reserves, which may consist of organized volunteer fire companies as out- lined above or may be simply an available labour supply at some adjacent centre where arrangements for securing men have been made through labour agencies or other means. Whatever is the form and composition of the Supports and Reserves, the mobiliza- tion, equipment, and transportation of these forces to the fire-lime must be (handled by the 'supervisory officer and his staff. Fire plans, which are an essential feature of specialized fire protection, detail the means for accomplishing this concentration, but the expeditious carrying out of the features of such a plan is largely dependent upon the system of communication. 3 — MAINTENANCE AND DIRECTION OF SUPPRESSION FORCES Finally, the supervisory officer must provide for the maintenance of his forces on the fire-line and the direction of the work of suppression by these forces. In this, his problems differ, from that of the military officer in no material aspect except the merely rudimentary development of his medical service -and the absence from his transportation columns of anything corresponding to the enormous quantity of ammunition required by modern troops. A complete discussion of this phase of the function of supervision 10 METHODS OF COMMUNICATION FOR FOREST PROTECTION , might constitute the subject matter of a manual of forest protection and is beyond the scope of a manual on communication alone, but the main divisions of it may be very briefly considered. In doing so, however, it is necessary to recollect that although the object of all fire-protection forces is principally to prevent fires, nevertheless the supreme test will come in the actual handling of a dangerous forest fire and all organization must be based upon preparation for this contingency. This, of necessity, involves a somewhat elaborate organization which must be provided though it may never in prac- tice be utilized for the purpose intended. From this it does not necessarily follow that a staff is held idle merely awaiting emergencies that no effort is spared to avoid. On the contrary, the skill of the organizer is shown by the way the necessary staff is secured for emergency work without continuous maintenance. This force as already indicated is divided into line and staff according to the nature of its duties. Section 11 — Duties of Suppression Staff Officers These are five in number and give rise to five separate departments, but it is seldom, even in a very dangerous region, that all are separately organized. 1 — TRANSPORT The transportation problem becomes important only when relatively large fires must be fought at a considerable distance from a base of supplies. Its difficulties arise more from the poor quality of the lines of communication over which trans- portation takes place than from any other factor. Crews seldom exceed 100 men though more than 1,000 have at times been engaged in one locality. Distances are sometimes considerable, frequently 25 miles beyond the railways, sometimes more than 100 miles. Wagons, boats, or pack-horses are the usual equipment employed. Sometimes motor-cars may be used but on the other hand1 it is sometimes necessary to pack supplies on men's backs. When, as is nearly always the case in the western forests, pack-horses are the only feasible means of transport, the maintenance of a hundred men on a fire-line is quite as difficult a transport problem as is the main- tenance of 2,000 or 3,000 men in a country where modern motor-trucks may be employed. The transport service in a specialized force is seldom under the direct charge of the supervisory officer having immediate charge of the smallest fire-protection district or unit of area. As a rule ten or more such districts are combined under an officer of higher rank and. the transport service for the entire group is handled from a central headquarters. Where necessary a chief transport officer, genemlly called the " packmaster," is employed for this purpose. A very important element of transportation is the condition of the lines of com- munication, such as roads and trails. It must be the constant aim of a forest- protection force to improve these lines at every possible opportunity. In the accom- pF.shment of this an intercommunicating system is of the highest importance. Its value arises from the fact that in scarcely any forest region is the fire season continu- ous, but owing to rains there are periods of greater or less length when no fire is likely to occur. The efficient organization will plan to use the fire-protection staff during such periods for the extension or improvement of lines of communication. This is accomplished by preparing in advance careful plans for necessary improve- ments to roads, trails, or other permanent works, distributing the work as much as possible to all districts. Immediately on the occurrence of a heavy "rain, the fire- control force is swung on to improvement work through the medium of the inter- communication system and is kept employed on this work at the discretion of the supervising officer until conditions again require a return to fire-control duties. The SPECIALIZED FOREST PROTECTION 11 amount of work that may be accomplished in this way depends on the seasonal condi- tions but it rarely happens that a fairly considerable total does not result from careful preliminary preparation and skilful use of opportunity and of the means of communication available. 2 — COMMISSARY The bulk of the material handled by the transport service to fire-fighting crews is food'. This is supplied in the most successfully organized forest districts through a central depot which distributes to a group of fire-control districts, generally the same group as is handled by a single transport officer. The officer in charge of the commissary is called the " quartermaster " and, in fact, very often combines the duties ,of quartermaster with those of packmaster. He arranges for the delivery of the necessary food, tools, and miscellaneous camp supplies, such as tobacco, son dtry sites. In the first three the under- brush is likely to be heavy and the bark thick on old trees or the branches abundant on young trees. In large yellow pine and fir some difficulty is experienced in climbing trees because of their size and loose bark, and where trees stand in the way of the line they are very costly either to fell or to trim up. High-altitude stands are usually fairly clear of underbrush and the trees are a fair size if usable at all, but the branches are dense. The most difficult types through which to build tree lines are Do'iiglas fir on wot sites on the Pacific coast, white spruce or red spruce, Engelmann spruce at low ele- vations, cedar, and, above all, hemlock, especially western hemlock. The mixed coni- ferous forests of the moister regions of British Columbia come under this head, as well as a great deal of the northern forest belt and the eastern spruce forests. The difficulties encountered in these types arise from the large amount of underbrush* that has to be cleared, the density of the timber, and the low-branching habits of these species. Hemlocks are particularly bad because the lower branches are excessively long and have a very pronounced downward sweep. Often large branches of hemlock have to be cut from trees standing 15 to 20 feet fco one side of the line in order to free the wire. 2 — YOUNG TIMBER In building lines through very young- timber or reproduction of any species there is often no choice as to type of construction, that may be employed, since none of the young trees may be large enough to serve as supports. Very often, however, there are standing dead snags as remnants of the original forest, which may be so utilized. Unless the necessity for economy is very great or poles are extremely inaccessible, the use of such snags for long lines is not advisable. If used, care should be taken to see that as many as possible of the dead trees adjacent to the line are felled, that abundant slack is left in the line, and that it is made easily accessible for the purposes of repairs, as maintenance charges are likely to be high. The continued felling of nearby snags should be made a part of the regular work of the protection staff and a gradual replace- ment of the tree line by a pole lime should be the object of the maintenance work. If young timber, of such a size that trees large enough to furnish supports are available, is encountered very careful consideration should be given to the advisability of adopting pole-line construction. A decision will be based largely on the cost of right-of-way clearing which is determined by the size and especially by the density of the young stands. Where these are very open, pole lines will usually be preferred. A makeshift method of construction sometimes adopted under these and similar con- ditions consists in making the necessary right-of-way clearing, often in the form of a wagon ro'ad, but leaving at the required intervals suitable trees to serve as the sup- ports for the telephone line. These trees should not be topped. The cost of making arid- setting poles is thus saved but it must be realized that a line thus located is likely to interfere with the use of the road and that provision for replacing these supports with poles must be made a part of the work of line maintenance. A similar situation is often met by the builder of forest telephone lines, even in certain species of timbers of commercial size in the forests of the Prairie Provinces and of the East. This is most likely to be the case in poplar or jack pine stands. Both species frequently grow in rather open forests, and where they occur in such stands righl-of-way clearing is comparatively inexpensive. Moreover, unless th« 32 METHODS OF COMMUNICATION FOR FOREST PROTECTION poplar is old and defective, windfall is light and the width of clearing need not be excessive — 20 to 25 ft. in stands of sound green timber not over 40 to 50 ft. high being adequate. Care should be taken to cut all snags or defective trees, outside this right of way, that threaten to fall on the line. 3 — DEAD TIMBER There remains then only the question of dead standing timber. This is the most troublesome kind of .stand through which to build and maintain a telephone line. Whenever possible, such timber should be carefully avoided, even at the expense of a material lengthening of the line. The foregoing applies not only to forests in which all the trees are dead but also to forests in which a considerable proportion of the trees are dead or badly decayed and where windfalls are consequently frequent and such forests are extremely undesirable along the line. Where, as sometimes happens, it is entirely impossible to avoid constructing through such stands and an adequate right of way cannot be cleared, then the most careful attention must be given to the details of tree-line construction and the line must Toe constantly maintained in first-class con- dition. This latter is of extreme importance because the accumulation of several fallen snags across the line in a short distance will take up all the slack and cause the intervening portions to be drawn up very tightly. If this tight wire should happen to be caught on a projecting branch, or even if the ties fail to break as quickly as designed, then any new windfalls coming on the line will very likely cause a break. Even if no break occurs the line is sure to be very seriously strained and a large number of ties pulled off or broken, insulators smashed, and general havoc created. Only by careful and conscientious maintenance may lines be kept operating through large dead standing timber where windfall is frequent. Section 38 — Grounded versus Metallic Circuits A grounded circuit is one in which only a single wire is employed for the trans- mission of the calling and talking currents and the earth is utilized as the other half, or return portion, of the circuit. A metallic circuit employs two wires, the extra wire taking the place of the earth or return portion of the circuit in a grounded line. Contrary to what appears to be popular opinion it is not necessarily possible to talk farther over a metallic than over a grounded! circuit. On the contrary, since the earth for all practical purposes may be assumed to interpose no resistance to the return currents, provided the ground connections are well made and do not themselves offer a higher resistance, a grounded circuit will have only one-half the electrical resist- ance of a metallic circuit under similar conditions. From this it does not necessarily follow that it is possible to talk twice as far over a grounded circuit, because conditions other than the mere electrical resistance of the intervening wire have an important influence on the possibilities of long distance telephonic transmission. The usefulness of metallic circuits arises from the possibilities of eliminating from them, by suitable transpositions, all induced currents from other electrical circuits such as power, light, telegraph, or telephone lines that may exist in their vicinity. The extraneous noises or cross-talk on a grounded circuit of even short length which runs close to such cur- rents often make distinct speech transmission impossible, regardless of the electrical resistance of the line itself. By using a two-wire, or metallic, circuit such interference from outside sources may be eliminated by transposition, and communication is thus rendered possible where a one-wire, or grounded, line cannot be used at all. Where, however, difficulties in transmission arise, not from interference by induced currents but from excessive length of lines, poor insulation, bad joints, poor " grounds," or other defects in construction, the installation of a metallic circuit will give no relief. Excessive line length can only be remedied by using a more efficient conductor. Thus, CONSTRUCTION POLICY IN FOREST RESERVES 33 the standard galvanized-iron wire used in. ordinary forest lines would have to be replaced by a larger wire or preferably by copper wire, which is a much more satisfac- tory electrical conductor than iron wire. If the trouble arises from faulty construc- tion it can only be remedied by removing these faults. The installation of a second wire would, otherwise, be more likely to increase than to decrease the difficulties. For forest-protection purposes a grounded line is nearly always preferable to a metallic line. As previously stated, only grounded lines can be satisfactorily employed in tree-line construction. The employment of two wires not only magnifies the chance for interruptions due to breaks in the line but also renders a metallic line liable to interruption from short circuits in ways that do not occur with grounded lines. Thus, if the two wires became crossed, as would often happen when a tree fell across the line, or if a wet branch or a loose tie wire fell across both wires, the line would fail to work. Metallic circuits, therefore, should as a rule only be used on full pole lines and then only when needed to counteract interference from induced currents. Where disturbances due to induction are encountered in only a part of a line, it is not neces- sary to make the entire line a metallic circuit, but only that portion where the dis- turbance occurs. The means by which this is accomplished will be discussed in Chapters XII and XIY (See Figs. 56, 58, 59, 60 and 86). CHAPTER VI TELEPHONE CONSTRUCTION POLICY IN DOMINION FOREST RESERVES Section 39 — Construction by the Forestry Branch The intention of the Forestry Branch is to secure efficiency of fire protection on the forest reserves by such specialization as the controlling factors seem to warrant. This will involve the establishment of rapid means of intercommunication. To accomplish this, telephone lines have been built and will be extended- wherever their use will ensure more effective fire protection and more economical administration, and where the territory covered is not served, or probably will not be served, by com- mercial lines on account of inaccessibility and absence of subscribers. In general, telephone lines on the forest reserves will be located in accordance with the principles already discussed in Chapters IY and Y. For the most part, the commercial telephone lines near the forest reserves are own- ed and operated by the government of the various provinces, except in British Columbia where they are largely operated by the Dominion Department of Public Works. Wherever feasible, these lines should be utilized in order to lessen the necessary con- struction of Forestry Branch lines. Section 40 — Co-operative and Private Lines Co-operation between the Forestry Branch and companies, individuals, provinces, or other government departments that would involve joint ownership, construction, or maintenance of telephone lines, introduces a division of responsibility which may affect communication and maintenance as well as future growth and extensions, and, there- fore, should be avoided. Exceptions may be made in the case of the lines of the Department of Public Works in British Columbia and, in unusual instances, in the case of provincial telephone departments, but all such instances must be referred to the Director of Forestry for approval. 79211—3 34 METHODS OF OOMMUNICATWN FOR FOREST PROTECTION The construction of privately owned lines within the reserves should be encouraged. Permits for such lines, when they will be of material benefit to the forest reserve should be recommended for issuance under Regulation 65 (" Regulations for Dominion Forest Reserves," 1916) and the conditions varied so as to afford the necessary encouragement in each case. Regulation 21 authorizes the granting of free construction materials for structures on roads and trails on condition that they become the property of the Crown, and Regulations 18 and 19 provide for the furnishing of materials at special rates when the removal of the material will benefit the reserve. Supervisors, therefore, should accompany all recommendations for issuance of permits for the construction of private telephone lines within forest reserves by a report regarding the class of construction materials that it will be necessary to obtain from the forest reserve, if any, and a recommendation regarding the price that should be charged in case special consideration is believed justifiable. Free service for a specified number of connections made by the Forestry Branch on all such lines will be made a part of all such permits. Section 41 — Use of Forestry Branch Lines The connection of privately owned instruments with Forestry Branch lines will not be permitted. The conditions under which these lines are constructed and main- tained necessarily reduces to a minimum the number of telephones that may be operated on them. Each telephone adds to the electrical load and lessens by this amount the reserve capacity for future growth and, more particularly, for emergencies. Under no circumstances can such a number of instruments be regularly connected to a Forestry Branch line that its entire capacity is employed, since the exigencies of forest administration may at any time require the establishment of one or more additional temporary connections with portable instruments or emergency lines. The possibilities of extensions are also extremely important in this connection. A line 10 miles long might easily carry ten to fifteen telephones, but if this line is extended to form part of a circuit 100 miles long the probability is that all but one or two of these telephones would have to be removed in order to get any use of the line. Now, it is found that where telephone service has once been granted in an isolated region it is relinquished only with the greatest reluctance and therefore forest officers should weigh all these points very carefully when considering any connections other than those at ranger stations. All instruments connected with a Forestry Branch line will be provided, installed, and maintained by the Forestry Branch. Instruments may be installed by super- visors at logging camps, mines, or other private establishments, but only where such installations are necessary for the proper administration and protection of the forest, where suitable arrangements can be made for the protection of the instrument and the securing of access to it by forest officers at all times, and only after approval of the installations has been received from the district inspector. It will be the duty of supervisors contemplating such installation to report fully to the district inspector the conditions which warrant the placing of an instrument at that point, the character of the building in which it will be placed, and the service that may be secured, and to report annually as to the advisability of maintaining or discontinuing the installation. Such stations will, as a rule, be located only in buildings of a public or semi-public character such as stores, post offices, hotels, road-houses, logging-camps, etc., and only where the location is of material importance to the reserve work and the person owning the establishment is under agreement to perform some special service for the Forestry Branch. The telephone lines of the Forestry Branch are not to be considered commercial in character. It is not the intention to enter into competition with any private or provincial telephone service. Hence no action such as the granting of telephone ser- vices to settlers along these limes, with an annual charge for the privilege, will be permitted. It is obvious that any such permits will inevitably raise the question of CONSTRUCTION POLICY IN FOREST RESER^7ES 35 discrimination, since it is wholly unreasonable to expect that such service can be granted to all that may apply, as1 would be done on commercial lines. These lines are built for the specific purpose of assisting in the administration and protection of the forest reserves, their capacity is extremely limited, the connections needed by the Forestry Branch are subject to sudden and unforeseeable increases, and accidents to which these lines are particularly liable may at any time very 'greatly impair their carrying capacity. For these reasons any attempt to render commercial service will inevitably fail, and no connections will be made Which are not in the opinion of the supervisor and the district inspector essential to the proper administration and pro- tection of the reserve. Forestry Branch lines, however, are open for public use free of charge so far as the portion of the line owned by the Forestry Branch is concerned. Where provincial or other foreign lines are used in connection with a forest line the usual toll charges must be paid. Section 42 — Telephone Improvement Plans Within one year after the issuance of these instructions all supervisors and rangers in charge of Dominion forest reserves asre required to prepare and submit to the district inspector and the Director of Forestry a complete plan for the equipment of the reserve with telephone lines. This plan will include a map and a report The map should show existing Forestry Branch and private lines and their character, and the location of exchanges and instruments, also the location and character of all new construction which will be necessary to meet the needs of Forestry Branch business during the next five years. In addition, the map should show high- tension electric transmission lines, roads, trails, ranger stations, lookout stations, and all other features which may influence the establishment of the system. The report should discuss, in the order of their importance, the proposed new lines, their need, location, character, and cost. The telephone system should be grouped by natural divisions, eaich being designated by its two terminals. A branch line should be designated by its terminal and the division of which it is a branch. The district inspector will prepare, from the information furnished by the supervisors, a map of the entire district showing the existing and proposed lines. This will ensure co-ordination of plans between the various reserves and with private systems. He will then issue instructions covering the general plan of the telephone system for each reserve. Section 43 — Standard Methods Since the Forestry Branch lines are primarily for fire protection purposes they should embody the best principles of construction, and every precaution should be taken to ensure continuity and dependability of communication over them at all times and especially during fire seasons. 1 — DESIRABILITY OF STANDARDS To ensure that the best principles of construction shall be followed on all reserves it is essential that the direction of telephone development be centralized and this necessarily involves the issuance of uniform standard instructions. Such standard methods may be based on the experience, not alone of all the various Forestry Branch officers, but also on that of other protection services, and new discoveries or improve- ments can, therefore, be applied generally throughout the forest reserves. Moreover, it is only by employing standardized methods that the use of standard equipment is made possible. 2' — AMOUNT OF LINE WARRANTED BY PROTECTION STANDARDS As yet, the determination of exact standards of protection on forest lands in Canada has progressed only a relatively short dietanct*. It is possible to give only 79211—3* 36 METHODS OF COMMUNICATION FOR FOREST PROTECTION very general statements in regard to the actual degree of immunity from fire damage that may be considered satisfactory in specific instances, consequently, it is possible to state only in a very general way the amount of line that may be considered essential in any given case: On the forest reserves, where continuous forest production must be aimed at in order to justify their existence, it is obvious that if the area annually mimed over averages more than about 1 per cent this aim will be rendered wholly unattainable. It is doubtful, moreover, whether with an average annual fire loss exceeding one-tenth of 1 per cent (1 acre per 1,000) of the area protected satisfactory results are possible. Certainly an average annual loss of 2 acres per 1,000 in the reserves of the P'rairie Provinces should be the outside limit. 'What expenditure may justifiably be made to attain this degree of protection depends on many factors, not all of which are as yet known in these forests. From a study of protective services in other regions, however, it may be said that present protection standards on Dominion forests demand the connection of all district ranger headquarters with the supervisor by telephone, and the equipment of primary lookout stations at least. Further con- struction can only be of real utility as the efficiency of the staff develops and as its further specialization becomes feasible. In a general way an- internal system that will connect all district headquarters with the supervisor will be found to involve about 200 miles of line to each million acres of forest. Since this is a greater mileage than can be successfully operated on one circuit, it is necessary to divide it into two or more independent circuits in preparing the telephone plan. Section 44 — Standard Materials 1 — DESIRABILITY OF STANDARDS Several factors combine to render the adoption of equipment standards impera- tive. Certain technical reasons require the use of uniform types of instruments on the one circuit. Only by adopting a standard type for all circuits is it possible to connect up adjacent ones or to transfer equipment from one to another. Some important special instruments are manufactured for use only with certain types of equipment. Unless these types are employed it is impossible to utilize all the available facilities. Dealers will carry in stock only materials for which there is a reasonable demand. The adoption of uniform standard equipment for all the work of the Forestry Branch will make it possible for dealers to carry at local distributing- centres a supply of this material, and thus greatly expedite deliveries. For the purpose of providing uniform equipment throughout the Dominion forest reserves the following standard list has been adopted and must not be deviated from without the authority of the district inspector. 2 — LIST OF STANDARD EQUIPMENT NOTE. — For specifications of those items marked with an asterisk (*) see Appendix E. Material and Uses Description of Equipment *Wire: — Standard Line (pole and tree, grounded and metallic). No. 9. B.W.G., B.B. galvanized-iron telephone wire. Specials Line (special long distance tree lines, grounded only) No. 6 B.W.G., B.B. galvanized-iron telephone wire. CONSTRUCTION POLICY IN FOREST RESERVES 37 Material and Uses— Con. Description of Equipment — Con. Con. Line (special short pole lines only) Nos. 12 and 14 B.W.G., B.B. galvanized -iron } telephone wire. Line (special extra long distance pole lines only, mostly metallic) Nos. 8 and 12 and 14 B. & S. gauge hard-drawn copper as required. Line spans, 500 feet and over Steel wire as required. Emergency lines No. 20 stranded, consisting of 10 strands of No. 30 B. & S. gauge, hard-drawn copper wire, insulated. From line to fuse No. 14 B. & S. gauge, rubber-covered, braided, weather-proofed copper wire. Single for grounded line, twisted-pair for metallic. From fuse to protector No. 14 B. & S. gauge, rubber-covered, braided, weather-proofed copper wire. Single for grounded line, twisted-pair for metallic. From protector to all inside apparatus, in- cluding telephone No. 19 B. & S. gauge, rubber-covered and braided copper wire. Single or twisted-pair. From protector to ground No. 14 B. & S. gauge, rubber-covered, braided and weather-proofed copper wire. Single. From line wire to portable telephone Special Forestry Branch portable connector. "Poles : — Line supports (standard) 22J ft. long by 6 in. diameter at top. Green, or sound dead, peeled cedar, or other species, with open tank butt treatment. Line supports (special) 18-ft. to 45-ft. cedar poles for special construc- tion. Species other than cedar with special treatment. Attachments, Wire to Poles : — *Brackets 12-in. oak bracket, painted or oiled. Nails 6-in. and 4-in. galvanized-iron wire nails. "•Insulators Glass, regular pony long-distance 14-oz., deep groove for No. 9 iron wire. Glass No. 9 pony for copper and No. 12 iron wire. Tie Wires No. 9 B.W.G. galvanized-iron wire on No. 9 wire lines. Nos. 8, 12, 14 B. & S. gauge, soft copper wire on same gauge copper lines. Attachments, Wire to Trees : — Fastener 3-in. or 4-in. wrought-iron staples, according to bark thickness. Tie Wires Nos. 9 or 12 B.W.G. galvanized-iron wire, according to tie employed. *Insulator No. 37 improved split tree insulator No. 6651. Linemen's Tools : — Climbers Eastern type (in ordering state length desired) straps and pads are supplied separately. Belts with rings and safety straps 2}-in. (in ordering state length desired). Pliers, for cutting wire and making ties and splices /.8-in. linemen's side-cutting, with sleeve-twister, Klein make or equal. Combination wire and sleeve splicing-clamps, for making splices Reversible for sleeves (Nos. 8 to 12) and wire (Nos. 6 to 14), Klein make or equal. 38 METHODS OF- COMMUNICATION FOR FOREST PROTECTION Material and Uses — Con. Description of Equipment — Con. Linemen's Tools — Con. Hand-axe for trimming trees and driving nails and staples 26-oz. Hudson Bay hand-axe with 22-in. handle. Mclntyre sleeves, for splicing copper wire..Nos. 8, 12, and 14 copper Mclntyre sleeves for copper wire only. Pole-setters' Tools: — Shovels, for digging holes for poles 7-ft. handle, round point. Digging spoons, for digging holes for poles.. 7-ft. handle, flat-toed, medium. Combined digging spud and tamping bar, for digging holes and tamping poles in soft ground S-ft., steel. Digging and tamping bar, for digging holes in gravel or hard ground . 1-in. octagonal steel, 8 ft. long. Specials Pike-poles, for raising and steadying' poles 30 ft. and over in length 12 ft., 14 ft. and 16 ft. long, according to length . of poles. Pole supports, for raising large poles Mule or jenny pattern, generally made on the job if required. Post-hole auger, for digging holes in soft ground 10-in. auger, Iwan's type with 6-ft. handle. Guys and Braces : — Bolts, for holding top of brace to pole g-in. galvanized-iron bolt, square head, square washers, 2J by 2| by %6 in. and nut. Lengths according to size of poles. Guy rods, for fastening guy wires to anchor logs i-in. diameter by 5 ft. or 6 ft. long, galvanized- iron with washer and nut. Guy wires, for guying poles at sharp turns, long spans, etc Nos. 9 or 12 B.W.G. galvanized-iron wire, 2 or 4 strands, twisted. Line-stringing Tools : — Pay-out reel, pole and tree lines Horizontal type only. Made on job according to specifications. Pay-out reel, emergency wire lines Special Forestry Branch hand-reel made to order only. Buffalo grips, for holding and stretching wire on pole lines only Buffalo grips with pulley for No. 9 wire and smaller. Haven clamp, for holding and stretching guys and line wire Haven clamp with 2-in. to 3 -in. double blocks and 36 ft. of |-in. sash cord. Telephone Instruments : — For supervisors' offices Desk set: type, Northern Electric No. 1300-A or equal. (Note. — When it is desired to equip a desk set with a head receiver the district inspector will advise as to the equipment to order). For lookout stations, permanent Same as for supervisors. For ranger stations permanently occupied. . .Wall set; type, Northern Electric No. 1317-S or equal, with 2,500-ohm unbiased ringer and condenser. CONSTRUCTION POLICY IN FOREST RESERVES 39 Material and Uses — Con. Description of Equipment Con. Telephone Instruments — Con. For ranger and patrol stations unoccupied during winter months, open lookout towers and any outdoor stations along patrol routes or elsewhere Weather-proof iron box telephone; type, North- ern Electric No. 1336-J or equal with 2,500-ohm unbiased ringer and condenser. For speeder patrolmen, special crews, or fire- camps on lines not equipped for buzzer signalling Special Forest Service portable telephone; Northern Electric No. 1375-A. For patrolmen, special crews, " smoke chasers" and all field service units on lines equipped for buzzer signalling Special Adams portable telephone; Northern Electric No. 1004-A. Emergency Telephone Kits : — For temporary camps on fires or special pro- jects Special Forestry Branch emergency communi- cation kit No. 1-A. Protective Devices : — Lightning-arrester, for lightning only Protector; type, Northern Electric No. 60-E or equal. Order separately protector blocks, Northern Electric Nos. 20 and 21 or equal, and No. 10 protector block mica. Lightning-arrester, for lightning and high- tension currents Protector; type, Northern Electric No. 5S-F or equal. Same as above with addition of 2-ampere to 7-ampere No. 11-C tubular fuses. Fuses, for outdoor installation Type, Northern Electric No. 4 7- A or equal. Protector blocks and micas for repairs . . . . Protector blocks ; type, Northern Electric Nos. 20 and 21 or equal. Protector micas ; type, Northern Electric No. 10 or equal. *Svvitch and protector mounting-box, for all permanent outdoor telephones Type, Northern Electric No. D-400 or equal. Protector mats, to be placed under No. 58-F protector Type, Northern Electric No. 48 or equal. Lightning rods, for carrying lightning to ground, on pole lines only No. 9 B.W.O., galvanized-iron wire, 2-in. galvanized-iron fence-staples. Dry Batteries : — For station telephones, desk and wall sets ... Type, Northern Electric "3 in 1" battery Blue Label, or equal. For weather-proof lookout telephones Type. Northern Electric telephone battery or equal. For Forest Service • portable telephone No. 1375-A Columbia O.V. No. 3 or Ever Ready Tungsten No. 703. For Adams portable Telephone No. 1004-A.. Ever Ready Tungsten No. 705. Special Signalling Devices : — Extension bells For stations indoors Type, Northern Electric No. 127-F or equal, with 2.500-ohm unbiased ringer. 40 METHO'DS OF COMMUNICATION FOR FOREST PROTECTION Material and Uses — Con. Description of Eqwpment — Con. Special Signalling Devices — Con. For statons outdoors Type, Northern Electric No. 292-U or equal, with 6-in. galvanized gongs and 2,500-ohm unbiased ringers. Howlers, for signalling by means of vibratory currents as with 1004-A telephone Type, Northern Electric No. 1-C or equal. Condenser, for use with howler to impede bell-signalling currents Type, Northern Electric No. 21-F or equal. Repeating Coils : — For connecting grounded to metallic line or taking out a phantom circuit Repeating coil; type, Northern Electric, No. 47- A or equal. Station Installations : — Fasteners for outside wiring No. 4i solid, or No. 5| one-groove, split por- celain insulator; Nos. 14 or 16, 3-in. flat- head wood screws. Fasteners for inside wiring, single or double. . J-in. or 1-in. Blake insulated staples. Fasteners for inside wiring, double only.. . . i-in. milonite nails. Insulation for wires through walls Porcelain tubes, unglazed, diameter |-in. by n/ie-in. Length according to wall thick- ness. Switches, for test stations, central switching stations, unoccupied stations, etc Single or double pole 15-ampere baby knife- switches on porcelain bases. Screws, for attaching protectors, switches, howlers, etc., to walls ..Blued, round-head screws, length and gauge according to size of each article. Installation and Repair Tools : — Pliers For cutting insulated wire 5-in. oblique, side-cutting pliers, Klein or equal. For tightening binding-posts and small nuts. 5-in. or 6-in. long-nosed, oval, side-cutting pliers. Screw-drivers For setting small wood screws 4-in. machinists' style screw-driver. For setting large wood screws 8-in. machinists' style screw-driver. For setting screws in instruments 2£-in. machinists' style screw-driver. Knives, for general insulated wire work.. ..Electricians' knife; type, Northern Electric No. 402 or equal. Soldering torch, for heating soldering irons. .Clayton and Lambert gasolene blow torch No. 38. Soldering copper For soldering joints and other outside work. |-pound standard soldering copper. For interior work and repairs to instru- ments Pony soldering copper No 2, ll|-in. handle, weight, 3 oz. Installation and Repair Supplies : — Solder Resin-core flux solder, 1-pound or 5-pound spools, half-and-half bar solder. Flux Allen soldering stick, 1 by 5£-in. TaPe Black friction tape, S-in. Northern Electric grade A or equal. CONSTRUCTION POLICY IN FOREST RESERVES 41 Material and Uses — Con. Description of Equip mem --Con. Grounding Devices : — Ground rods, for all ordinary indoor and out- door instrument installations on grounded lines Galvanized-iron ground rod with copper wire attached ; i in. diameter by 7 ft. long, Northern Electric or equal. Ground rods, for metallic circuits only.. ..Galvanized or plain iron ground rod, J in. dia- meter by 6 ft. long, Northern Electric No. 388 or equal. Ground plates, for special ground installations. Copper plate No. 21 Birmingham sheet metal gauge or No. 21, U.S. sheet metal gauge; 12 by 18 in. or larger. Ground clamps, for grounding on water-pipes. . Northern Electric type A ground clamp or equal. Portable ground rod, for Forestry Branch emergency communication kit No. 1-A. . Special Forest Service portable ground rod, Northern Electric No. 313-B. Miscellaneous Tools and Supplies : — Brace and bits, for boring holes for brace bolts and guy rods and for carrying wires through walls Brace, ratchet, ball-bearing head, 10-in. sweep. Bits, auger or car bits ; i-in., fj-in., ii/ie-in., countersink. Other sizes as re- quired. Claw-hammer, for interior installations.. ..Ordinary style; light. Monkey-wrench, for setting up brace bolts and guy rods Standard wrench, 12-in. Pole-steps, for poles over 30 ft. high, bearing test station or other special apparatus. .Galvanized-iron poles-steps, |-in. by 9-in. Tree-trimmers, for trimming small branches from ground ' Type, Northern Electric Co., New Giant tree- trimmer or equal. Insulators, strain, for dead-ending line wire on trees and poles Type, White Strain Insulator No. 500 or equal. Strand, standard galvanized steel, for attach- ing strain insulators No. IS double galvanized-steel seizing strand. CHAPTER VII OPERATIONS PRELIMINARY TO CONSTRUCTION Section 45 — Factors Influencing Location The relation of the proposed line to the telephone system, present and proposed, should be kept constantly in mind. This will influence the type and character of construction. If the proposed line is a trunk line the possibility of connecting to it short branch lines from lookout points and ranger and fire stations should be con- sidered. The following additional points should be observed when locating telephone lines: — (1) The location of the most logical switching centres for connection with other lines. (2) Topographical location. By avoiding steep slopes, cliffs, high divides, river- beds, coulees, and streams, and canyons more than 500 ft. in width, the danger from snowslides, landslides, floods, and high winds will be lessened. By following roads and main trails frequent inspection will be facilitated and maintenance simplified. (3) Location of other electrical circuits. Electric-light, power, and high-tension transmission lines should be avoided whenever possible. A high-tension transmission line carrying over 5000 volts should not be paralleled at a distance of less than -one-half mile, and all crossings and approaches between telephone and power transmission lines should be at right angles. (4) The probabilities of future growth and extensions. (5) The length of the line. Other costs being equal, the cost of construction and maintenance varies as the length of the line. Section 46— Survey of Route A preliminary survey or reconnaissance is necessary in order that the length of the line may be ascertained and its cost estimated. The thoroughness of the survey will depend upon local conditions. A transit. line with chained distances may be necessary in some cases, while in others a walking or riding reconnaissance will be sufficient. The location determined by the survey, however, need not be taken as final; deviations from it should be made if it 's found during the course of construc- tion that greater reliability can thus be secured. Whenever a pole line is to be constructed, either in whole or in part, marking stakes should be set in line at the proposed locations of the holes. Each stake should be marked to indicate the height of the pole for that particular position, the depth of the hole, the kind of hole to be dug (whether an anchor-hole or a stub-hole), whether the pole is to be guyed or braced, and the amount of the rake (Fig. 11) at curves and corners. Each tree that is to be used as a tie tree should be prominently blazed fore and aft, and on the side to which the split insulator is to be attached. A cross made with blue crayon should be placed on the latter blaze. Section 47 — Securing Right of Way If it is proposed to build any part of the line off the reserve, or over alienated land within the reserve boundary, right of way should first be obtained. The proper form, which will be furnished by the district inspector, should be used. Verbal per- mission is not sufficient. 42 Fig'. 5 Mobley wire-cradle as used with two coils Fig. 6 Mobley wire-cradle as used with one coil 43 44 METHODS OF COMMUNICATION FOR FOREST PROTECTION In nearly all the western provinces the use of the public roads as the right of way for telephone lines is controlled by the provincial government. Before any lines are placed on such roads permission must be secured from the proper government department. This must in all cases be taken up through the district inspector. If it is desired to string wire on poles belonging to a private company written permission should be secured from the inspector before any construction is begun. Section 48 — Clearing Right of Way When a pole line is to be constructed, a right of way sufficiently wide to afford reasonable protection against dlamage to the line from falling trees must be cleared. It is especially necessary that dead or defective trees that lean toward the right of way and threaten to fall across it be removed. The effect of snow on adjacent trees and branches must always be considered, and all that might be borne down across the line should be cut. As a rule pole lines will not be built in the forest if a cleared right of way of greater than 25-ft. width is needed, unless the trees are exceptionally scattered. ] Fig. 7 Mobley wire-cradle. When pole lines are carried through small timber or reproduction a right of way at least wide enough for a saddle trail should be cleared through any dense under- brush. Small trees directly under the wire, which by their future growth might touch the wire, should be cut down at the outset. Everything, in fact, that might at pre- sent or in the near future cause trouble on the line should1 'be cleared before or at the time the wire is strung. If the line is to be attached to trees it is not advisable or necessary to top the trees to which the split insulators are fastened, except where the line has to cross over a windy canyon or in other places exposed to a strong wind. Under such conditions the trees should either be topped or else poles used, preferably the latter. It is usually only necessary to trim the branches on the insulator side of the tree to a sufficient height for attaching the split insulator. Undergrowth and trees between spans should OPERATIONS PRELIMINARY TO CONSTRUCTION 45 be trimmed sufficiently to allow at least a 4-ft. clearance of the line wire. Any dan- gerous snags or rotten trees in the close vicinity of the line should be cut. A right-of- way clearing for a tree line must usually be at least 8 ft. wide at the height above the ground at which the wire will hang. This is quite different from an 8-ft. clearing on the ground, particularly in long-branching species such as spruce, hemlock, and cedar, but care must be taken to see that sufficient clearing is made before the wire is strung, as otherwise annoying and costly delays result. In clearing lines through dense underbrush and reproduction, it will be found most satisfactory to scatter the clearing crew singly along the line and have all Fig. Klondike pack-frame as used for packing wire material felled into the right of way. The debris resulting from such clearing adds to the fire-danger and should, if practicable, be burned on the right of way before the wire is strung. If not practicable, the brush should be piled off the right of way and left for burning at a time when conditions are favourable. Section 49 — Transportation and Distribution of Materials The wire, brackets, insulators, and other equipment should be conveyed? from the railway point or the place of purchase to the proposed line by automobiles, teams, or horses. Time and money will be saved if construction work is ndt started until all necessary line equipment has been distributed to its proposed location or to some con- venient point. Wire and other metal should be kept off the ground. All line materials should be distributed along the right of way well in advance of wire-string- 46 METHODS OF COMMUNICATION FOR FOREST PROTECTION ing crews. Much time will be saved' if the ^-mile points (or J-mile points) at which coils of wire are to be left are marked in advance of the teams or pack-horses. Use a blaze with a red cross or some other distinctive mark. It will often be necessary to pack the wire on horses. The maximum load for one horse under best conditions is two 4-mile coils of No. 9 wire (weight 104: pounds each) and under poor conditions, one i-mile coil (weight 157 pounds). Single coils may be packed on a horse in several ways, but the following method is suggested : Run a cross-stick lengthwise between the cross-trees on the pack-saddle, tying each end securely. Then split the coil of wire in half and place it over the top of the stick connecting the cross-trees, so that one-half of the coil is on each side of the saddle. Finally, throw a diamond hitch over the whole. 1 — MOBLEY WIRE-CRADLE. A still better method adapted to packing either one or two coils is to use a pack- ing-cradle such as the one designed by Ranger Mobley of the Forestry Branch. Thi? cradle (Fig. 7) consists of a rectangular wooden frame built to fit snugly over the forks of the pack-saddle. The front and near pieces project a few inches beyond the sides and two pieces of strap-iron with upturned ends are so placed as to hold the side coils in place. In packing two coils, one is hung on each side of the horse on the pro- jecting ends of the cradle and then lashed on with a diamond hitch. When packing one coil it is laid flat on the top of the cradle and lashed in place. This cradle is par- ticularly handy when distributing coils along the line, since it is equally convenient for packing either one or two coils (Figs. 5 and 6). For packing heavy coils of wire on men's backs the Klondike pack-frame shown in Fig. 8 is an unusually effective device. f Section 50 — Organization and Equipment of Construction Crews. The foreman will be responsible for the work on the line in accordance with the instructions he receives. Whenever possible he should be a forest officer, carefully selected for his experience in telephone construction and in (handling men. The size of the crew will depend upon the extent of the work, the qualifications of the indi- vidual members, and the time available for completion. A crew may consist of a foreman, one ground assistant, two linemen, one utility man (swamper and lineman), and, if necessary, a cook. If more speed is desired, one or two additional linemen may be employed, provided arrangement is made to " swamp " the line and distribute materials with sufficient rapidity, to do which may require one or two additional groundmen. Which members of the crew will dig the holes, which distribute ttoe material, and which erect the poles will be determined by local conditions. Each man employed in digging holes for poles should foe provided with:— One 7-ft. shovel, Western Union pattern. One medium weight, straight-handled, flat-toed, spoon, Western Union pattern, 7-ft. handle. . One 1-in. by 8-ft. octagon steel digging bar. In sand or other easy digging a post-hole auger can often be used to advantage. Each lineman on tree lines should be provided with the following equipments-- One combination wire-and-sleeve splicing-clamp. This is of the reversible type, one side being used for Mclntyre sleeves and the other for Western Union connection. One pair 8-in. linemen's pliers. One pair of Eastern climbers, with straps. These run from 14 to 19-in. in length by 1-in. intervals. One belt and safety strap. One hand-axe. One bag insulators and tie wires. A construction crew on pole-line work should also be provided with : — Two Buffalo grips. One Haven's steel clamp. One 3-in. double-pulley block (with one hook). One 3-in. double-pulley block (with hook and eye). Thirty-five ft. g-in. sash cord. CHAPTER VIII POLE-LINE CONSTRUCTION Section 51 — Selection of Poles Poles should be cut as near the proposed line as practicable. The best and most durable timber, such as cedar, tamarack, and Douglas fir, should be used, if it can be obtained at a reasonable cost. All poles should be cut from live or dead standing trees and should be free from heart-rot or butt-rot, or any other defect which might weaken them. As a means of reducing- the cost of poles delivered at the hole it may in some cases be desirable to purchase poles from commercial companies. Whenever possible poles and braces should be cut in winter to secure better season- ing. They should be peeled as soon as cut and all knots and branches trimmed close. Unpeeled poles must not ~be used under any circumstances. Poles should be reason- ably straight and of the dimensions shown in the table below : — TABLE A— LENGTH AND TOP DIAMETER OF STANDARD POLES Length of pole Diameter of top Length of pole Diameter of top ft. in. ft. in. 18 6 35 7 22> 6 40 8 25 6 45 10 to 11 3>0' 6 to 7 When a line will be subjected to severe stresses from high winds or unusual strains, these diameters should be increased by from % inch to 1 inch. High poles should be very fine quality. The butts of poles should be cut off square; the tops should be cut slanting on both sides to form a right-angled " roof " as in Eig. 10. Section 52— Skidding and Seasoning It is sometimes possible to collect a number of poles or braces at one point as they are cut, and later to distribute them along the line without undue expense. In sucih cases the poles should be completely barked and piled in tiers, with a space of at least 6 inches between poles in the same tier and between tiers. The bottom tier should be of sufficient height from the ground to allow of the free circulation of air under the poles, which should be seasoned for at least two or three months. Seasoned poles are lighter and therefore easier to handle. Poles should not be held in storage too long as they are liable to start to decay. When it is not feasible to collect poles or braces at one point, the individual pieces should be peeled and raised off the ground or leaned against trees or rocks in an open position to season. Sound dead timber need not be seasoned. It is particularly necessary, when poles are to be treated with any form of pre- servative, that they be well seasoned and, so far as possible, be accumulated at a very few places along the line. In most cases it will be found desirable to prepare such poles a season before line construction is contemplated'. Section 53 — Preservative Treatment If durable woods cannot be obtained at a reasonable cost it may be necessary to give the poles preservative treatment. Before doing this, however, the district inspector should be consulted. The poles of branch lines less than 3 miles long need not be treated in any case, unless the branch is constructed at the same time as a main line of treated, poles1. 47 48 METHO'DS OF COMMUNICATION FOR FOREST PROTECTION The experience of the Forestry Branch with untreated' spruce amd poplar poles in the Prairie Provinces has shown that they have a length of life of only 3 to 5 years. Eastern tamarack poles are somewhat better, lasting from 6 to 9 years. Experiments have just been begun with lodgepole pine on Dominion reserves, but experience with this species in the United States has shown that its dependable length of life, untreated, is not over 7 years. Jack pine will, probably, be about the same. It is considered that permanent trunk lines on the forest reserves should be built to last without pole renewals on a large scale for at least 15 years. This may be accomplished by using either well-seasoned, untreated cedar poles or well-treated native poles. Special instructions with regard to the use of untreated and treated poles on Forestry Branch lines will be issued by the Director of Forestry. There are only two methods of pole preservation that may be applied with a reasonable degree of success under the conditions usually encountered on forest protection lines. These are the " open- tank " method and the " brush method." The latter gives only a very slight increase in durability and i® only desirable under certain very special circumstances. The former is the most successful method yet devised for the type of line employed by the Forestry Branch. Treatment is applied only to the portion of the pole placed in the ground. In some cases it may be preferable to treat & ft. or 9 ft. stubs and set poles as explained in Section 91. Before any treatment is applied all adhering bark, including the inner fibrous bark, should be removed with a draw-knife from the por- tion of the pole to be treated. A's the details of the treating apparatus and the methods of treatment have not yet been standardized for Forestry Branch lines, only a brief reference to these methods can be made at present amd complete instructions will later be issued in the fo'rm of a supplement to this manual. In the meantime, pole treatment will only be under- taken in accordance with specific instructions issued by the district inspectors. 1 — OPEN-TANK METHOD Wherever practicable, this method of treatment is the best that can be employed. Creosote, heated to a temperature not to exceed 200° F., is the preservative used. (See "Preservative Treatment of Poles," United 'States Forest 'Service Bulletin ISTo. 84, and "Preservative Treatment of Fence-posts," Forestry Branch 'Circular No. 6.) 2 — BRUSH TREATMENT This process requires less equipment than any other, but the results are not nearly so good as the open- tank method. Brush treatment even when well done can- not be depended on to add more than 2 or 3 years to the life of a pole. A brief descrip- tion follows : Hot creosote oir hot carbolineum is applied to the poles with iron-bound brushes for a space of about 1 ft. above the ground line and 2 ft. below it, thus form- ing a band 3 ft. wide. All seasoning checks and knot holes should be carefully filled and the preservative applied as freely as possible without waste, putting on all that the poles will absorb. After an interval of at least 24 hours the poles should be treated with a second coat applied in the same manner. In hot, dry weather the creosote should be heated to a temperature of from 120° to 150° F. and in cold weather to 180° F. These temperatures, however, should not be exceeded. In heating the creosote the utmost precaution should be taken to pre- vent accidents. If the heating vessel is allowed to boil over or if creosote is spilled and allowed to burn on the outside of the vessel, the contents are pretty sure to ignite and burn fiercely. If creosote becomes mixed with water the mixture boils violently several degrees below the boiling point of the latter. The preservative should never be applied to green timber nor when the surface of the pole is wet from rain, snow or frost, or is frozen. POLE-LINE CONSTRUCTION 49 The tops of the poles and the places where the brackets and braces are to be attached should also be treated with two coats of hot creosote, and the same is true of the butts of braces and the slanting top which is to rest against the pole. A convenient outfit for brush treatment consists of a 5-gal. or 10-gal. can or iron pot, a 3-gal. pail, i-gal. dipper, a 4-in. or 5-in. wire-bound brush, and a thermometer. A small-sized, galvanized-iron wash-tub has been used with success in some places as a vessel in which to heat creosote oil. Section 54— Length of Poles The standard pole is 22£ ft. long, and this dimension will be used in all but special cases. When for any reason non-durable poles must 'be used without preservative treat- ment, the standard length will be 25 ft. and no shorter poles may be used without specific authority from the district inspector. Poles shorter than 22^ ft. may be used, with the approval of the district inspector, provided the standard length is not available, or, for some reason, is undesirable. When a line crosses solid rock, and when it would be cheaper, the use of 2-in. or 2^-in. wrought-iron pipes for short-length poles should be considered, notwithstanding their liability to rust. Such poles may be fitted into drilled holes, thereby making blasting unnecessary. There are several forms of commercial brackets and pins which, by the use of a little ingenuity, may be set into the top of these poles or fastened to the side by carriage bolts. Poles longer than 22£ ft. may be used: — (1) Where the spacing of the poles is such that the required sag in the line would bring the wire too close to the ground. (2) Where the underbrush exceeds 10 ft. in height. Use poles that will keep the lowest wire at least 4 ft. above the highest brush at the middle of the span. (3) Where snow is likely to drift to depths exceeding 10 ft. use poles that will keep the lowest wire at least 2 ft. above the maximum height of the drift at the middle of the span. (4) Where it is necessary to grade the line to overcome abrupt changes in level. For example there should not be an abrupt change from a 22|-ft. pple to a 45-ft. pole. Instead after a 22^-ft. pole place a 30-ft. pole and then complete the change by using poles of gradually increasing length until the 45-ft. length is reached. (5) Where the line crosses wagon roads or railways. Use poles that will allow a clearance between the lowest wire and the road-bed of at least 16 ft. above a road and 25 ft. above a railway, measured from the middle or highest point of the road or track. Greater heights must be maintained if required by provincial laws. (See "Cross- ings," Section 66.) (6) Where necessary to cross over instead of under other poles. (See "Cross- ings," Section 66.) (7) At the ends of long spans (more than 500 ft.) across rivers and canyons. Special poles or construction, approved by the district inspector, should be used. Poles shorter than 22£ ft. may be used: — (1) On short lines where the standard length pole cannot be readily secured. (2) When stubs of durable species or treated with creosote are employed. Before using short poles the approval of the district inspector must be secured. No pole less than 18 ft. long or 5 in. in diameter at the top may be employed. Section 55 — Erection of Poles 1 — DISTRIBUTION OF POLES In distributing poles along a line the heaviest ones should be selected for use on curves, at corners, at the ends of long spans, and at terminals. 79211—4 50 METHODS OF COMMUNICATION FOR FOREST PROTECTION 2 — SPACING On straight sections poles should be set 176 ft. apart, which is equivalent to 30 poles per mile. For a grounded line, carried on poles, the distance apart, under favourable conditions, may be 200 ft., or about 26 poles to the mile. Changes in the direction of a line should be made gradually by spreading the curve over as many poles as possible, raking each pole outward to offset the strain. On curves and corners where the pull is from 10 to 30 ft., the pole spacing should be reduced to 100 ft. Where the pull js more than 30 ft., the turn will be made on two poles, approximately 100 ft. apart, with equal spacings in the adjacent spans on either side. At right-angled corners the length' of the section on either side next to the corner pole should not exceed 100 ft. Where it is necessary to make a span of from 200 to 300 ft., the adjacent sections' should be 100 ft. in length. Spans of from 300 to 500 ft. should have two sections of 100 ft: on each end. For spans of more than 500' ft. special construction is required. Where the line crosses solid rock, the length of spans may be increased v,p to 300 ft. to avoid the expense of blasting holes. When it is necessary to blast many holes, special construction may be d'esirable, and the matter should be taken up with the district inspector. Abrupt changes in the level of the wire should be avoided. Poles1 shoald be set on either side of a high or low point, using long poles, if necessary, to obtain the desired clearance in the span. In crossing a ridge or ravine, for example, it is better to space the poles so that one is set on each side of the ridge or ravine rather than to set a pole on the crest or in the bottom. 3 — DIGGING HOLES On straight sections holes should be vertical, uniform in siz? speci- fications are approximate and may be exceeded without harm. Rake is sorietimes necessary even though the pole is braced or guyed. POLE-LINE CONSTRUCTION 53 Poles should be set with the roof ridges at right angles to the line wire, except when cross-arms are used or when it is probable that they will later be used, in which case the ridge will parallel the line. The bracket should be exactly at right angles to the line and in the proper position to prevent the line wire from touching the pole X=/7 MOUNT OF RAKE' TO BE PROW D ED ON CURVES AND CORNERS Pig1. 11 Definition of rake POLE POLE THE PULL OA/ CORNER POLE A EQUALS D/MEM5/OU X MEASURED O/V GROUMD L/A/E USE 5 AM E METHOD DETERM/M/MG PULL OA/ EACH POLE /M /? Fig. 12 Definition of pull 54 METHODS OF COMMUNICATION FOR FOREST PROTECTION 6 — FILLING AND TAMPING In setting a pole it should he " trued " and held in position with pike-poles until firm, the dirt being filled in evenly around it and thoroughly tamped as the filling progresses (Fig. 13). The coarse soil or gravel should be put in last. The filling ean be done by one man, and the tamping by two men. After the pole is set and the hole filled, about 6 in. of earth should be closely packed around the pole above the ground. Poles set in solid rock should have rock fragments firmly wedged in around them. Fig. 13 Setting a pole Section 56 — Bracing and Guying The use of braces and guys is obviated in many cases by a proper amount of rake, but either bracing or guying will be necessary in the following cases : — (1) On any pole oil a curve or at a corner where the pull exceeds 30 ft. (2) On poles at each side of a crossing over roads and railway rights of way. (3) On the two end poles of spans between 300 and 500 ft. (4) On the poles at either end of spans above 500 ft. (5) On very steep slopes. Anchor guys may preferably be used in these cases, or a head guy from the to-p of one pole (below the lowest bracket) to the base of the pole next above it. (6) On alternate poles in exposed positions. (7) On poles in swamps or on loose ground (where necessary.) (8) On poles on both ends of high-tension transmission line crossings. (9) On the first and last poles of a line. 1 — 'BRACES Braces (Fig. 14) should be at least 8 in. in diameter at the butt end, cut slanting at the top to fit close to the pole but the pole itself should not be cut. They should POLE-LINE CONSTRUCTION 55 be set at least 2£ ft. in the ground — 3£ ft. would be better if too much difficulty is not encountered in digging. The distance between the brace and the pole, as measured on the ground, should be not less than one-half of the height of the pole above ground. The bottom end of the brace should rest on a flat stone or piece of log or plank. After boring a £-in. hole through both the brace and the pole just above the point where the bottom edge of the brace touches the latter, the brace should be bolted tightly to the pole with a f-in. galvanized-iron bolt, using galvanized-iron washer, 21-in. square and tc-in. thick under both the head of the bolt and under the nut. Do no? cuf or notch ~ff>e //ne po/e- Sroce po/e shou/d ' 6e ~f/tfe< fo //ne po/e Washer- Fig1. 14 Method of bracing 2 — GUYS (a) Anchor Guys. — Anchor guys (Fig. 15) should be made of two pieces of line wire (No. 9 B.W.G.) twisted together, and, if possible, of sufficient length to reach from the bottom of the lowest 'bracket to a point on the ground at a distance from the bottom of the pole equal to the height of the bracket above the ground1, but under no 56 METHODS OF OOMMUNICATION FOR FOREST PROTECTION condition less than 8 ft., with enough additional length to allow one end to be passed through the eye of a standard half-inch, galvanized-iron guy rod, the other to be wrapped twice around the pole, and both, secured. When a guy has been prepared, one end should be wrapped around the pole twice and stapled, the loose end beinig secured by wrapping not less than six times around the wire, using a pair of connectors or pliers. An anchor log should then be placed in the ground with a guy rod passing through it, the eye of the rod projecting above the ground. One of a pair of pulley blocks should then be hooked into the eye and the other fastened to a Buffalo grip or a medium-sized Haven clamp attached to the guy wire. The latter should then be pulled to the required' tension and the end looped through the eye and secured by not less than six wraps (Fig. 15), after which the pulley blocks and Buffalo grip can be removed. The size of the anchor log will usually be determined by the depth below ground. If the depth of the excavation be 4£ ft. the anchor log should be 4 ft. long by 5 in. in diameter; if the excavation be 3-| ft. deep the anchor log should be 5 or 7 ft. long by 8 or 6 in. in diameter. Wof fess-fhon 6 METHOD Or GUY/ KG X*- When X equals 4'/i -feet- use anchor /og 4ft et-/onobyS/n cf/ameie> - * • 3& - - « / -*• • •> - 8 . • \pr7 - - 6 - • Two wraps oround-fhe po/e Cra/van/zed iron rtuf and sefuore •asr>er on end1 of guy rod Fig. 15 Method of guying If guy rods are not available, the guy wire should be wrapped around the anchor log. This is temporary construction, as the guy wire will rust and break. When a guy is used on a public highway or street in a city or town, a guard should be used to make it readily visible. For this purpose it may be boxed up to a height of 6 ft. above the ground, or a sapling about 3 in. in diameter may be wired to it. This protection is also desirable where guy wires are necessary on open meadows, etc., frequented by men or stock. (b) Tree guys. — If there is a live tree of large diameter nearby, the guy wire may be fastened to it instead of to a buried log. Hardwood slats should be used between the guy wire and the tree to prevent injury to the latter, as in Fig 33. POLE -LINE CONSTRUCTION 57 (c) Rock guys. — A home-made iron eye-bolt 1 inch in diameter and not less than 18 in. long may be used' for anchoring a guy wire in rock. The angle formed by the guy wire and the shank of the bolt should not be more than a right angle (Fig. 16). The bolt should not be near the edge of the rock or ledge. (d) Guying across roads. — If a guy wire, as ordinarily placed, would interfere with traffic on a road, a stub should be used (Fig. 17) to provide proper clearance. The stub should be stayed with the standard guy rod and anchor log; or if this is not- possible, braced with anchor logs underground, as shown for the pole in Fig. 18. _ strands #9 B.W.6. galvanized /ro/ w/ re fwisted together^ or four stranc " 12 B. W G (shown as single w/re to simplify ///ustrat/on ) Not Jess than 6 wraps I inc-h diameter iron rod not /ess than /8 inches //? lengthfdepending on nature of roc k Do not locate near the edge of the rock Fig. 16 Rock guy bolt 3 — SELF-SUPPORTING POLES Where conditions prevent the use of any other method of guying, and especially in swampy soil, the poles should be braced with anchor logs, >as illustrated in Fig. 18. The problem of supporting poles in muskegs is often a difficult one. Where ordinary methods of single bracing or guying will not suffice two or even four brace? may sometimes be necessary in addition to anchor logs placed as shown in Fig. 18. 4 — TRIPODS The difficulties encountered in supporting poles in muskegs are often increased by unusual soil conditions which make the digging of holes very costly. Some success has been met in the employment of tripods instead of poles in crossing such muskegs. These tripods are constructed of peeled poles having a butt diameter of 5 in., top diameter of not less than 3 in., and a length of 22 to 24 ft. Lodgepole pine is the most suitable material, but spruce, tamarack, or jack pine may be used. Each tripod con- 58 METHO'DS OF OOMMUNICATfON FOR FOREST PROTECTION sists of two 22-ft. and one 24-ft. pole and these poles are wired together through holes bored 21 ft. from the butt end so that they may be raised or lowered at will. The longer pole thus projects 2 ft. beyond the other two and from it the line wire is suspended in a split tree insulator. The butts of the poles are not set in holes Fig. 17 Method of using guy stub 'ill r=~ s-7U Grouncf /?bouf/-fo<. 3p ^ & L/n& pN^lli^U^i - c//'omefe/~ 6 /nches -fo /O/nches mef/iod of ground orac/ng may be L/secf for po/es or guy &fubs when nofposs/b/e /o anchor fr/e Fig. 18 Method of ground bracing but are set directly on the ground surface, and to prevent them sinking into soft soil a 5-ft. cross-log about 4 in. in diameter may be spiked or wired1 to the lower end of each leg. POLE-LINE CONSTRUCTION 59 Fig. 19 Tripod line supports Section 57 — Line Construction 1 — LINE MATERIALS Iron wire is divided into three grades: Extra Best Best, Best Best, and Steel. The Extra Best Best (E.B.B.) wire possesses the highest conductivity, but the lowest tensile strength. It is designed for use on the main lines of telegraph companies, and by telephone companies where a wire of high conductivity combined with strength and toughness is required. The steel wire is made from a special grade of material. It is the lowest in conductivity but highest in tensile strength. The Best Best (B.B.) wire, which possesses intermediate qualities, is more generally used than the others on medium distance circuits by telephone companies and for railway work. The following table gives the physical characteristics of these three grades of wire : — TABLE C— PROPERTIES OF DOUBLE GALVANIZED TELEGRAPH AND TELEPHONE WIRE1 Diame- Weight Put up Approximate breaking strength Average resistance in ohms at No. ter in in in pounds 68° F. B W G ^ 11 1 Wire inches per mile of— E.B.B. B.B. Steel E.B.B. B.B. Steel Mile 4. . 0-238 811 i 2 433 2 676 3 000 5-98 7-15 8-32 6 •203 590 1,770 1,947 2,183 8-14 9-83 11-44 8 •165 390 i 1,170 1,287 1,443 12-43 14-87 17-31 9 •148 314 \ 942 1,036 1,162 15-44 18-47 21-62 10... •134 258 % 774 851 955 18-80 22-48 26-16 11 •120 ?06 A 618 680 762 23-54 28-15 32-76 12.... •109 170 510 561 629 28-53 34-12 39-70 14.... •083 99 * 297 327 366 49-00 58-58 68-18 Summary of tests bv John A. Roebling's Sons Co. 60 METHODS OF COMMUNICATION FOR FOREST PROTECTION All iron wire should be well galvanized to protect it from the corrosive action of the weather. (For specifications see Appendix E.) Its life is 15 to 30 years and it has little or no wrecking value when removed. Hard-drawn coppei\ wire' possesses great conductivity and high tensile strength and does not deteriorate when exposed to the weather. It is therefore well adapted for telephone lines. More difficulty is encountered, however, in obtaining good elec- trieal joints when splicing copper wire than when splicing iron wire. Copper wire is of particular value where unusual construction is required, such as on very important trunk lines over 125 miles in length, on metallic circuits, etc. It lasts almost indefinitely and has a wrecking value equal to 80 per cent of its first cost. 21 — STANDARD CONSTRUCTION A one-wire line (grounded circuit) of No. 9 B.W.G., Best Best galvanized-iron wire will be the standard construction on the forest reserves. No other method ishould be used unless the permission of the district inspector is first obtained. If the line is located outside of the reserve where there are no trees, No. 12 B.W.G. galvanized wire may be Used, provided the length is short. Metallic circuit lines are used only where there is outside interference, such as cross-talk, induction, or trouble from power-transmission lines'. It is not possible to talk any farther over a metallic circuit line than over a grounded circuit line provided the grounds of the latter are made properly. Where the length of a line exceeds 125 miles it will prob- ably be necessary to use copper wire. This cannot be used with swinging insulators and will not be employed except on a strictly pole line. Where necessary, a two-wire line (metallic circuit) of copper wire may be used. For spans up to 500 ft. the No. 9 galvanized-iron wire should be used, except when the circuit is of hard-drawn copper wire. For longer spans steel wire or other forms of special construction will be necessary. No. 12 New British Standard gauge (N.B.S.G.) hard-drawn copper wire should not be used on spans longer than 300 ft., nor No. 14 N.B.S.G. hard-drawn copper wire on spans longer than 200 ft. If the circuit is of No. 12 N.B.S.G. hard-drawn copper wire and it is necessary to make spans longer than 300 ft., No. 8 N.B.S.G. hard-drawn copper wire should be used for the spans from 301' to 500 ft. If the circuit is of No. 14 N.B.S.G. hard-drawn copper wire and it is necessary to make spans longer than 200 ft., No. 12 N.B.S.G. hard-drawn copper wire should be used on spans from 201 to 300 ft. 3 — CAUTIONS Great caution must be used during lightning storms'. While lightning is being discharged in the vicinity of the work, and as long as there is any danger from this source, no line wire or any wire electrically connected .should ~be handled or touched. 4 — STRINGING WIRE There are several satisfactory methods of removing the wire from the reel, and which one to use will be determined by the conditions in each particular case. A man familiar with the location of the line and with the transpositions should be in charge of the Unreeling of the wire. In paying out the wire care should be taken to place it on the proper side of poles or trees, in order to avoid cutting it. Splices should be as few in number as possible. When the conditions permit the use of a wagon, the reel may be placed in the back and the wire laid upon the bracket? as fast as the wagon proceeds. Another method is to have the wire pulled out by a horse, either with a rope that can be released instantly, between the ends of the wire and the traces of the horse, or by tying the end of the wire to the horn of the saddle, with a man watching the reel. Where the line is very crooked the reel should be placed at less1 than one- half mile from the starting point. POLE-LINE CONSTRUCTION 61 Instead of using a wagon or horse, the wire may be unreeled by three men, one of whom should be stationed at the reel to see that the wire is not paid out too fast and to signal in case it becomes kinked or tangled. Another method in forest reserve work is for two men to carry the reel, paying out the wire as they go. This method only should be used in stringing copper wire, as this wire should never be dragged on the ground. Wire should not be paid out from a coil held by one man, since it comes off badly twisted and? is likely to kink. Always use a reel. Hard-drawn copper wire must be handled much more carefully than galvanized-iron wire. The coil should not be thrown from a wagon to the ground. Before commenc- ing to unreel it, the first 15 or 20 loops of the coil should be carefully lifted by hand to guarantee that there are no " crossovers." Hard-drawn copper wire should never be dragged on the ground while being strung. If a wagon cannot be used1 to carry the reel, it should be carried by several men. Care must be exercised when starting to unreel a coil to see that the outer end of the wire is taken off. This end is generally indicated by having attached to it a small tin tag on which the weight of the coil is stamped. The pay-out reel handled by the supply houses is of hardwood bound with iron straps. Its weight often precludes its use on lines following trails land through timber. A home-made reel is much lighter and less expensive. This consists of two parts, a support and the reel proper (Fig. 20). Fig. 20 Home-made reel The support is made of two 2-by-4-in. pieces AA, each 5 ft. long and held 2 ft. apart by two cross-pieces BOB of 2-by-4-in. stuff, nailed between and 1 ft. each side of the centre of the long pieces. Midway between the long pieces and fastened to the cross- pieces is a 2-by-6-in. stick C. To secure greater rigidity, a 2-by-4-in. stick D is mitred to fit from the centre of one side to the centre of one of the cross-pieces. At the centre of stick C a block 6 in. square and 1 in. thick is attached, and through its centre and through stick C a f-in. hole is bored. Around this hole on top of the block a 2-in. irooi washer is attached with screws, the heads of which are well countersunk. A bolt E, 14 in. by | in. with square head is then inserted in the hole in C from below, and held in place by countersinking the square head on the underside of C and nailing a small block F over it. The reel is made of two pieces of 2uby-4-in. stuff, preferably Douglas fir or some other strong wood, GG 2 ft. 9 in. long and mortised in the middle to form a cross. After these have been fitted together a 1-in. hole is bored through the centre and a piece of 1-in. iron pipe H, 9 in. long and threaded for 2 in. at the end is screwed firmly into 'this hole. On the underside around the hole a 2-in. iron washer is fastened to act as a bearing. Nine inches from the centre on each arm G a f-in. standard K, 18 in. long and shaped as illustrated, is 62 METHODS OF COMMUNICATION FOR FOREST PROTECTION set upright and held in place by two nuts N, one on each side of the arm. Care must be taken to see that these standards do not project below the arms more than the thick- ness of the lower nut. The portion threaded should equal the thickness of the arm plus the thickness of the two nuts. The cost of the whole apparatus is so small that after the iron fittings are removed' the rest may be discarded, if necessary, when the work is completed. No more wire should be strung out than can be put up and tied in during one day. Special care should be taken not to allow the wire to lie across trails or roads where it might be run over by vehicles or trampled by animals. Kinks or nicks made in this way may weaken the wire sufficiently to cause it to break as soon as a little strain is put upon it, or when it contracts in cold weather. All kinks should be straightened before the wire is stretched. If the kinks or nicks are bad' they should be cut out and a splice made. 5 — TRANSPOSING LINES By transposition is meant changing the lo'cation of a wire from one side of the. pole to the other (Fig. 21). This is1 done to overcome the effects of outside inter- ference existing in lines which are close to or parallel with high-tension transmission lines, and wires which are on poles carrying other wires-. Brace of brocket on reverse s/c/e ofsorne /eve/ ELEV/3T/OM PL/? A/ Fig. 21 Transposition of wires, metallic circuit When building a metallic circuit, the wires should be transposed once every mile. Where the line is exposed to induction, cross-talk, power wires or electric-light wires, the line wires should be transposed at least every tenth pole. In transposing telephone lines, the wire on the left should always cross over, never under, the wire on the right, and without touching it. On a bracket line the transposition can be made very easily by changing the location of the brackets on the pole, as shown by the upper diagram in Fig. 21. When a cross-arm is used, transpositions can best be made by using a standard two-piece transposition insulator. Transpositions should be arranged for at the time the wire is unreeled; the left-hand wire crossing over on top of the right at the point where the line is to be transposed. 6 — SAG ALLOWANCE The stresses in the telephone wire undergo changes with variations in temperature, thus making it necessary to provide for the extreme variations in wire length in each POLE-LINE CONSTRUCTION 63 span. The sag in the wire at the time it is made fast to the brackets should corre- spond to the temperature at that time. TABLE D— SAG OF A No. 9 B. W. G. GALVANIZED-IRON WIRE IN A POLE LINE Length of span in ft. Sag at temperature indicated in degrees F. + 100° +80° +60° +30° + 10° -10° -30° 75... 100 115 130 150 ft. in. 4£ 7" 9 11 1 2 1 6 1 10| 3 3£ 4 7 6 6 8 0 10 0 12 6 ft. in. 3 5i 8J 11* 1 3 1 7 2 10 4 1 5 6 7 0 9 0 11 0 ft. in. "'2 4! 5| 9 1 0 1 4 2 5| 3 6£ 4 11 6 6 8 0 9 6 ft. in. 2 3i 5i 9^ 1 0 1 11 2 9 3 10 5 0 6 6 8 0 ft. in. n 3 3* 4* 6 8 10| 1 8 2 5^ 3 5 4 6} 6 0 7 6 ft. in. n 2| 3 4 5 7 9 1 5^ 2 H 3 0 4 4 5 6 7 0 ft. in. 1 2 2i 3* 4| 6 8 1 3 1 10 2 7 3 7 5 0 6 0 176.. 200 260 300 . 350... 400 450 500 NOTK. — If a strong wind is blowing, the sag value should be increased. Interpolate for temperatures and spans not given. When any other size than a No. 9 B. W. G. wire is used, it will be necessary to com- pute the sag required. Instructions for doing this will be furnished by the district inspector. Sag may be handled in the following manner: After a half-mile reel of wire has been pulled out, linemen, who follow, carry the wire up each pole 011 their shoulders and place it between the bracket and the pole. When this has been done over the entire half mile, the line is stretched by means of a Buffalo grip and stretcher-block until it is taut, or until the two or three linemen who are on the poles along the half-mile stretch pass along the signal to stop. About two minutes' rest is then required for the line wire to " creep " along the entire distance. It should then be loosened or stretched tighter, according to the signals of the men on the poles, who can sight from the bracket of one pole to the brackets of the adjacent poles and determine when the proper amount of slack has been provided, 7— TYING IN WIRE On straight lines the wire should be tied to the inside of the insulator, so as to bring it between the insulator and the pole. On curves and corners the wire should be tied to the insulator on the outside, so that the strain will be against the bracket and the pole. On pole-line construction the tie wire (the wire used to fasten the main line to the insulator) should be of the same size as the line wire. The method of tying wire to a glass insulator is shown in Fig. 22. In making the tie great care should be exercised to avoid twisting the wire so tightly that the main line will be burned. Linemen should be cautioned against nicking the line wire in making ties, especially when this is hard-drawn copper. The latter should always be tied by hand. Pliers, connectors1, or other tools should be used only with iron wire. Linemen should also be cautioned against leaving the endte of the tie wire protruding, lest through twisting of the pole a contact be made. (a) Tying galvanized-iron wire. — There are two methods of tying galvanized-iroii wire. The regular tie (Fig. 22) should be used on all poles except where there are sharp dips or changes in level in the line .wire, or in crossing railway rights of way, or on spans from 250 to 500 ft. in which cases the " figure 8 " should be used (Fig. 23). 64 METHO'DS OF COMMUNICATION FOR FOREST PROTECTION When the work of stringing wire on a pole line is stopped for a short time, or at the end of the day, the last tie put on will be a figure 8 tie. The line wire will then be continued over the bracket of the next pole without being tied, and brought down and anchored to the butt of the next farther pole by means of a Buffalo grip and either stretcher-blocks or a snub. /Vof /ess l/ia/i~3 c/ose wraps TIG w/re to be of The same s/ze fie wire Fig-. 22 Method of making regular tie for iron wire Of Ga/i/ /rorr //ne w/re ffraff 3 c/o^e wraps 7/e w/rie /o be. same, fr/'rrd 0,5 //'ne. Fig. 23 Method of making " figure 8 " tie for iron wire The figure 8 tie is made by first bending the tie wire into a horseshoe shape just large enough to fit the insulator, putting it over the line wire (first position, Fig. 23), which has been placed in the groove of the insulator, and then bringing the two ends POLE-LINE CONSTRUCTION 65 of the tie wire around the insulator in opposite directions and wrapping them tightly around the line with not less than three wraps, as close together and as tight as possible, using pliers or connectors for the purpose. The line should be dead-ended (Fig. 24) at such places as the first or the last pole on a main or branch line, or at a station. (fr) Tying hard-drawn copper wire. — All tie wires for hard-drawn copper wire should be of the same size as the line, 'but of annealed (soft) copper. >Soft tie wires may be purchased in bundles or they can be made by cutting up the line wire and heating and then cooling it slowly to make it less brittle. Care should be taken not to heat the wire too hot, so that it pits, or to cool it too quickly. Hard-drawn copper wire is dead-ended by the use of a half-length, double-tube copper sleeve. The regular tie for copper wire (Fig. 26) should be used in all cases except where a figure 8 tie is required (Fig. 27). i less than Sc/ose. wraps Fig. 24 Method of dead-ending iron wire Ha •// length x/eeve - /%> Fig. 25 Method of dead-ending hard-drawn copper wire 8 — SPLICING WIRE The standard Western Union joint (Fig. 28) or the standard three-wire splice should be used for uniting galvanized-iron wire, and the standard double-tube copper 79211—5 66 METHODS OF COMMUNICATION FOR FOREST PROTECTION sleeve for hard-drawn copper wire (Fig. 29) ; galvanized-iron sleeves should not be used. Copper sleeves should not be used for splicing galvanized-iron wire, because the resulting corrosion of the latter results ultimately in a high-resistance joint which may become the equivalent, from an electrical standpoint, of several miles of extra line. Soft' copper t/e as A/of /ess Than 5 fusris .v _ Fig-. 26 Method of making- regular tie for hard-drawn copper wire When copper sleeves are used for joining hard^drawn copper wire, they should be twisted not less than three nor more than four turns with a pair of reversible con- nectors of the No. 309 type. The ends of the wire" should project approximately 1 in. from the end of the sleeve before twisting. After the sleeve is twisted the protruding ends of the wire should be cut off not closer than \ in. and bent back slightly on the sleeve. In ordering sleeves it is necessary to specify the size of the wire for which the sleeve is required. In making joints every precaution should be taken not to nick the wire, whether galvanized iron or copper. POLE-LINE CONSTRUCTION 67 //o/t/ dnzwrr copper f/'e wire same size as line w're n of f/e wire A/oT/ess thorr & Turns Fig. 27 Method of making "figure 8" tie for hard-drawn copper wire A 'of /ess fharr 3~ c/ose wraps Fig. 28 Method of splicing iron wire (Western Union joint) DouJ)/e. Tube, coppes-js/eere before, usfrrg S/ecve. offer using. Tivtsteci 3 to 4- fuJ/ turns ctepzn dirty on its /ength Fig. 29 Method of splicing hard-drawn copper wire 79211— 5 & CHAPTER TX TKEE-LINE CONSTEUCTION Section 58 — General Principles With a telephone line passing through a heavy stand of timber, the possibility of trees falling across the line makes it essential that the line wire should be able to give way without breaking. The rigidity so necessary for standard pole-line construction is therefore undesirable and even inimical to proper tree-line construction. The. tree-line method is generally used when poles are scarce or inaccessible, when ground conditions are unsuitable to the setting and maintenance of poles, or where there is not enough money available for the construction and maintenance of a standard pole-line. The essential features of the tree-line method are the use of the split insulator and a suspending wire support. The former allows the line wire to draw through it when there is a pull from one side; the latter permits the wire to be attached 'to the tree itself. Metallic-circuit tree lines are seldom used. Short circuits, resulting from broken wire ties and from trees falling across the lines, make this method of construction im- practicable under ordinary conditions. Where the danger from high-voltage trans- mission lines makes necessary the use of a metallic circuit, but other conditions make the use of a tree line desirable, the wires should be strung on separate trees and the standard methods of transposition followed. Under no circumstances may a metallic tree line be undertaken without authorization by the inspector. Section 59 — Selecting Trees and Route Judgment and care should be used in selecting the trees to support the line, and also in determining the tying place on each tree and the method of tying. Only sound trees should be selected, of sufficient diameter to minimize the swaying, but large and smooth tret^i that are difficult to climb should be avoided. The course of the line should be varied to take advantage of trees that will lessen the cost of construction; but if suitable trees are not available, poles should be used. In tree lines the spans should not exceed 175 feet. If possible the average span should approximate 100 feet, and may be shorter if necessary. The span should be equalized, that is adjacent spans should be as nearly of equal length as possible and no abrupt changes in length of spans should be made The crooks and turns of the trail should not be followed unless to do so would mean more economical and better construction. The line wire should never touch the trunk of a tree, and care should be taken when attaching the insulators to see that the pull of the wire is away from the tree and not against it. On side-hill slopes the line will be strung, if practicable, below the trail, so that in case the wire comes down it will not fall on the trail. Wherever possible avoid crossing the trail. In selecting trees for ties two systems of alignment are followed both of which give good results. In the first system (Fig. 30) the effort is made to select the trees so that they follow a regular zigzag course, each tree being on the opposite side of the right of way from the two adjacent ones. The amount of pull between adjacent trees on the same side of the right of way should be 6 to 8 feet. The wire then forms a zigzag over the cleared right of way and pulls away evenly from each tie tree. The insulator, of course, is attached on the inner, or concave, side of each crook in the line. 68 TREE-LINE CONSTRUCTION 69 In the second system (Fig. 31) the line is built in the form of a series of long reversed curves. On curves, while all insulators are on the same side of adjacent trees the wire nevertheless pulls away from all trees on the curve. By laying out the Fig. 3>0 Zigzag system of alignment 9 Fig. 31 Reverse curve system of alignment • entire line in a series of reverse curves, each of six or eight spans in length, the desired pull away from the tie trees is secured without the frequent crooks in the line encountered in the first method. Section 60 — Line Construction 1 — THE " Six EULES " FOR TREE-LINE WORK For successful tree-line construction, the following six rules should be kept con- stantly in mind: — 1 Slack wire. 2 Equalized spans. 3 Weak ties. 4 Standard installations. 5 No sharp turns in line. 6 Avoid attaching wire too high on trees. 2 — LINE MATERIALS For tree-line work, only No. 9 B.W.G., B.B., galvanized-iron wire, or heavier, can be successfully employed. This is true, regardless of the length of line. The strains to which tree lines are exposed are much greater than with pole lines and no wire of lighter weight than No. 9 will resist them successfully. Copper wire cannot be employed at all with this method of construction. Although tree-line methods involve the building of a very crooked line with a great deal of slack, the actual length of wire is not thereby seriously increased. Only about 100 feet per mile of line wire need be allowed for the normal crooks and slack of a standard tree line. For tie wire No. 12 B.W.G.. galvanized-iron wire is employed. A mile of No. 12 wire will s make about 2,700 tie wires or enough for approximately 60 miles of line, allowing 45 ties to the mile. Split tree insulators and 4-in. staples, sufficient for 45 to 50 ties per mile of liner are the only other line materials required. The latest form of split tree insulator (See 70 METHO'DS OF COMMUNICATION FOR FOREST PROTECTION Appendix E) which, is elliptical in cross-section not only avoids several of the more serious defects of the original circular and hexagonal types but is much heavier and of better material, and therefore stronger. It will be standard on all Forestry Branch lines. 3 — STRINGING WIRE The methods given in Section 57 are also applicable to tree-line construction, al- though the latter offers less opportunity for the use of a wagon. The same precaution should be taken not to injure the wire. In most cases the only practicable way to pull out the wire is by hand from a stationary reel. Where very thick brush is encountered along the right of way it will sometimes require three or four men to pull a half-mile length of No. 9 wire, with an additional man to tend the reel. Two men should take the end of the wire to which a cross-bar is attached for a handle, while the others distribute themselves along the right of way as the strain becomes heavy. It is import- ant to remember to remove the cross-bar from the end of the wire, and to straighten out the latter after having pulled out the coil. A large amount of slack -should be provided. The exact amount will be determined by the conditions, topography, etc., but, in general, each span should be given about 4 ft. The aim in to provide enough alack so that several trees may fall across the line within a few spans without breaking the main line. This should always be tested after the wire is up by catching hold of the line wire between supports and pulling to the ground. It should have sufficient slack to permit this to be done in every, span, and, where slack-holding ties are used, at least four times simultaneously between each pair. Under ordinary conditions the use of brackets in tree-line construction should be avoided. 4 — HEIGHT OF WIRE The wire should not be hung at a greater height than on a pole line and in general should be hung about 18 ft. above the ground at the point of attachment, giving 14 ft. at centre of span. 5 — SPLIT TREE INSULATOR ATTACHMENT The method of making the split tree insulator attachment is shown in Fig. 32. C and D are the insulator attachments that have given the best results. The former uses No. 12 wire and comes loose from the staple whenever a tree falls across the line. In such cases neither the tie wire itself nor the split insulator breaks. To make repairs it is merely necessary to replace the attachment on the staple as illustrated in the figure. The attachment D involves the same principle, but uses No. 9 wire. When this is employed it is necessary to keep only one kind of wire in stock, though the tie C is the least expensive and the easiest to make. E shows a little stronger attachment made of No. 12 wire which should be used in conjunction with the crosstie shown at A. All ties should be attached to the tree by means of a 3-in. or 4-in. staple, according to the thick- ness of the bark, about 1 in. of the staple being left protruding from the tree. A 2^-in. post staple may be used in hardwood timber. When there is a possibility that the tree to which the insulator is attached may be cut into sawlogs, a wire wrapped around the tree with a loop twisted in the middle should be used instead of tne staple. The staple should be set with its two points in a vertical plane. The split insulator is attached to the line wire by the lineman before climbing the tree. Particular care must be taken in forming the loop of the tie wire around the staple to see that it is snug and that the reversed ends are left about 2 in. long and closely parallel to the shank of the tie. A very great variation in the amount of pull required to detach this tie can be secured by altering the shape of the loop around the staple, and if not pro- TREE-LINE CONSTRUCTION 71 perly made it may be found that the ties pull loose under the weight of the line wire alone. This must, of course, be avoided and the ties so made that they will not only support the wire but also withstand the shock of falling trees up to the point where it threatens to break the line. Fig-. 32 Split tree insulator attachment and crosstie 6 — CROSSTIE Fig. 32 A illustrates a complete crosstie with a No. 9 wire runing through the in- sulator. Such >a tie should be used wherever it is desired to prevent the wire from run- ning back after breakage of the main line. It should be made of No. 12 wire and be from 20 to 25 in. long. This tie is usually preferable to the insulator and bracket dead- end, in that it lessens the chance of the main line being jerked by heavy winds. The line should be stayed at the top of hills or the beginning of steep slopes. It is not necessary to stay it on comparatively level ground if spans are properly equalized. The use of crossties should be avoided as much as possible. Perfect equalization of spans will enable this to be accomplished in any but mountainous country. 7 — DEAD-ENDING So far as is practicable lines should be dead-ended and poles set and .braced for that purpose. One or, if necessary, two brackets set close together may be used, the method of fastening wire being illustrated in Figs. 24 and 25. When dead-ending on trees the bracket-and-insulator method is not desirable, but instead the No. 500 white strain insulator attached to the tree by four to six wraps of standard galvanized strand should be used. The tree should be protected by four shims or cleats of wood. This method is illustrated in Fig 33. Dead-ends should be used in the following situations: — (1) At terminals of lines (2) At the ends of all extra long spans (3) At the tops of all long stretches of line, or steep slopes where the standard crosstie is not adequate to stand the strain. 72 METHODS OF OOMMVNICATION FOR FORREST PROTECTION 8— SPECIAL TYPES OF CONSTRUCTION - In regions where there is little timber and practically no danger from windfall a No. 3^ porcelain knob fastened to the tree with a 6-in. spike may be found satis- factory. It should not be used, however, without the permission of the district •4-Cemp/ete na stuff No. 5 00 insu/otor 6- Short turns. Pieces 6 wide /2"/ong 2" thick, either sp//t, hewn or- sawed, f>n four sides of tree. Fasten So tree with 2~5in.na//s. Dec/of- en ding on po/es- Omif protecting pieces and reduce fore space to 3 inches. Seiz/ng stuff may be fastened to po/es with nai Is, or common fence stap/es. //eiser- dead-end a line of y eater weight than SO ff. ofN M <'5 SJUfti/C J • W ^ > ^ il] 80 METHODS OF COMMUNICATION FOR FOREST PROTECTION Transmission lines should always be crossed at a right angle. Unless the dis- trict inspector specifies otherwise, or unless the transmission company has provided special and safe protection, the crossing will be made as follows: Dead-end the tele- phone line on each side of the transmission line, at least 150 ft. from the cross! im. and brace or guy the lasst poles. The actual crossing should be made underground by means of an extra heavily insulated, rubber-covered, braided, and weather-proofed No. 14 B. and S. copper wire run through a 1-in. iron pipe, starting at a point on the pole about 8 ft. above the ground. The joints in the pipe should be made water- tight by the use of red lead, and1 an inverted "U" attached to the top of each pipe, so that rain-water cannot follow the wire. The rubber-covered wire should extend up the pole and be connected to the line wire. In. crossing with a metallic circuit both wires may be run in the same pipe. This method is illustrated in Fig. 37. If considerable blasting would be required to put the iron pipe underground below the frost line, it may be laid across the surface of the rock, providing it is covered with an earth embankment to a depth of 2 or 3 ft. If permission is requested for a high-tension transmission line to cross an existing forest reserve telephone line, the Director will require that the transmission line be so constructed as to provide safe and approved protection for the Forestry Branch line. Where the telephone line is exposed to voltage in excess of 5,000 volts Order 231 of the Board of Railway Commissioners for Canada for overhead crossings of electric-light and power lines will be used as a basis for determining suitable protection. (See Appendix D.) 6 — SUBMARINE In many regions, particularly in the eastern forests of Canada, the necessity for crossing wide bodies of water with telephone lines arises with great frequency. •Often many miles of aerial construction can be saved by a comparatively short sub- marine span. If properly laid with suitable material, submarine lines involve almost no maintenance charges. Cost of installation is usually very low. Against these advantages, however, there are certain serious objections to submarine lines which must be fully considered. A suitable conductor, that may be depended upon to give uninterrupted service is likely\ to be very costly, particularly where there is any current in the body of water to be crossed. A break or leak in a submarine cable causes a complete interruption of the service and it is impossible to make temporary emergency repairs as with land lines, but the cable must be raised, often at considerable expense, and permanent repairs made before service can be resumed. A submarine cable has a very great electro-static capacity, many times greater than the same length of overhead wire, and the practical result is that a mile of such caole is equivalent to approximately 2.3 miles of well-built, standard land line. The use of even short submarine spans, therefore, in long land' lines must be carefully considered, not only from the standpoint of first cost and maintenance but also from the standpoint of their effect on the operating efficiency of the line. No submarine cables shall be purchased unless authorized by the Director^ and on specifications furnished by him, and no such cable shall be installed until the proposed site has been inspected and approved by the district inspector. As sub- marine cables for still-water spans over one-half mile in length, or for spans of any length in water having a perceptible current, may have to be manufactured to special specifications, field officers will be expected to report all such cases to the district inspector at least one year before construction is contemplated. In reporting, state length of water-span, character of current, if any, nature of bottom at each shore and in the middle of the span, depth of water at intervals from shore to shore, annual variation in water level, if any; and state whether or not the water is contaminated with industrial acids or other corrosive substances or is salt or brackish. A map of FOREIGN LINES AND CONNECTIONS 81 the proposed crossing site, showing the contour of the shore on each side for 500 •ft. from the water-line, and a profile of the body of water along the proposed line of crossing should accompany each report. Submarine telephone cables may be roughly divided into three classes: (1) Rubber-covered copper wire protected by two or more heavy servings of jute impregnated with waterproofing compound. (2) Rubber-covered and taped copper conductor, inclosed in a heavy lead sheath either bare or juted. (3) Rubber-covered, taped, and juted copper conductor inclosed in an armouring sheath of galvanized-iron wires, left bare or juted. There are no standard specifications for conductors of the third1 class for forest protection telephone lines and none are contemplated by the Forestry Branch, as the use of such lines on the reserves will be comparatively small. The cost of the heavy cables is so great that each case must be studied separately so that the lowest-priced cable that will give satisfactory service may be specified. Of the cables above described, the first is the least expensive; the last, the most. Rubber-covered wires that will give satisfactory service under unusually favourable conditions may be secured as low as $50 per mile. Heavily- armoured cables, proof against injury in all but the most adlverse sites, will cost from $500 per mile, up. Intermediate types will range between these figures in cost. In waters having any perceptible current, either the ordinary current in a stream, OP tidal or wind currents in other bodies of water, nothing but an armoured cable is likely to give satisfactory service. The nature of the currents, the contour of the crossing, and the character of the 'bottom will determine the weight of armour required. In still waters, such as large lakes or ponds, either heavily insulated wire or lead-sheathed wire may be used. Insulated wire without a lead! sheath should only be used in perfectly still water where there is a mud or sand bottom in which the wire will embed itself. Such waters will usually be shallow and have a fairly regular profile. If used for navigation or log-driving or rafting, the chances of the wire being disturbed by such operations must be fully considered. In nearly all cases, where the approach to the shore is on a gradual, shelving bottom, a heavy pile or tripod properly weighted should be set in the water at a sufficient distance from 'the shore to permit of the wire being brought to the surface in a water depth of £ ft. to 8 ft. and carried to shore by an overhead span. The probable effect of ice on this construction must be considered. Such spans should! not, as a rule, be over ^ mile to £ mile in length and should always be tested for some months before permanent shore structures are erected. If they fail, replace with a lead-sheathed cable, making the shore connection as above, and use the insulated wire for station installations or for emergency or temporary land lines. For spans of over \ mile in still water with a mud, sand, gravel, or rock bottom, where excessive irregularities of profile do not occur, the most satisfactory cable will be a lead-sheathed one. On a gravel or rock bottom it should have an outer jute covering. The shore approach may be made as previously described, but in most cases it will be found more satisfactory to splice on to each end of the span a short length of armoured cable with which to make the shore approach from a depth of about 15 ft. Landings may be made with armoured cable where the rock slopes off very steeply into deep water; or the cable may be brought ashore on a sand or mud bottom sunk in a trench and, if possible, protected by a light covering of rocks or gravel and a few stakes or piles to warn off boats. However, if logs drift loose in the lake, or if the landing place is exposed to a heavy surf, an overhead landing is preferable. Always set up at each end of a submarine cable crossing a large sign warning navigators against anchoring over the cable. The actual laying of a submarine cable is very simple. The reel on which it comes wound should be mounted on the stern of a boat of suitable size, or, if none is 7*9211-— % 82 METHODS OF COMMUNICATION FOR FOREST PROTECTION available, on a barge or raft. This is done by inserting a steel bar or pipe in the hole in the middle of the reel and supporting it at each end so that the reel will revolve easily on the bar. A brake by which it may be stopped should be improvised. The end of the cable should then be made fast to the shore and the boat run across to the other landing at a slow speed. Two men should tend the reel and see that the cable comes off evenly. Where any great irregularities in the profile of the bottom are known to exist special care -should be taken to ensure that the cable lies on the bottom throughout its length and that there are no unsupported spans. Section 67 — Connecting Forestry Branch Lines with Private Lines or Exchanges Whenever it is desirable to connect a Forestry Branch line with a private line or exchange, the district inspector should first be fully advised by letter as to what ar- rangements can be made for the connection, including a statement of the ability to obtain night, Sunday, or holiday service, if needed in emergencies. There should also be stated the length of the Forestry Branch line, and, in cases where it is desired to connect directly to another line, the length of such line; the character of its construc- f?ejL//ar /ron -f/e , M-ain fine Use test clomp here Ga/v /'ron _ . tc/. of branch //'n e — enough offer cfeacf encf/no~ on /nsu/crfor- X fo GOnnccrfo //ne cr-s shown Fig. 38 Method of connecting branch line to main line when both are galvanized-iron wire tion and maintenance ; the sizes and kinds of wire used in the construction of both lines, and whether one or both are grounded or metallic circuits; the number of instruments on both lines and the ohm capacity of the instruments on the line with which connec- tion is to be made. The district inspector will decide the best method of handling the matter and making the connections. Every precaution should be taken to make sure that trouble originating beyond the Forestry Branch line will not interfere with it. Section 68 — Branch Lines 1 — METHOD OF CONNECTION In attaching a branch to a main line, the former should be dead-ended on a separate bracket attached to the main line pole for that purpose, so that the strain of the branch line will not come on the connection (Fig. 38). A Fahnestock test-clamp may be used to connect the branch line to the main line instead of wrapping the end of the branch to the latter. The Fahnestock test-clamp is made in three grades : Entire clamp fully FOREIGN LINES AND CONNECTIONS 83 tinned, elamp half -tinned, and un tinned. The first type should be used for connecting two iron wires, the second for connecting a copper and an iron wire, and the third for connecting two copper wires. When the main line is of hard-drawn copper wire, it should be cut in two and dead-ended on the same insulator from both directions, splicing in additional wire if necessary. The ends after dead-ending should bereft long enough to be spliced together in a copper sleeve, so as to complete the circuit again. The branch line should then be dead-ended on a separate bracket and insulator, and, the connection made as in Fig. 39. r/o/f /engfh s/ccve Afer/n //ne Afa/r? //ne r/ard drawn copper w/' re Afa/n //ne cuf and dead ended *v/fh haff /engfh s/eev&s -from hofhd/ reef ions on/nsu/afor/7 <7S shown f^nds /eff/ong enoug* offer dead end/ ng fo besp//ce together as shown r/ard drawn copper w/re Soffcoppcr w/re same size asorancfi //ne ~i rubber covered 6ro/dedand weafherproofcd copper M /re) 7 wraps a f each end as shown •So/dc/ •Shown ~for one w/re //nc Carounded c/rcu/f) ~fo//ow same mefhod for mcfa///c c/rcu/f Fig. 39 Method of connecting branch line to main line when both are hard-drawn copper wire Whenever any wire is connected to a hard-drawn copper line, the latter must always be dead-ended for that purpose, so that the wire may be soldered to a point on the dead-end loop between the sleeve and the insulator. When soldering is not feasible, the wire should be cleaned bright, and the wire to be connected should be closely wrapped around the line wire not less than seven times. A Fahnestock clamp may be used here also. When connecting a branch line to a tree line the branch should be dead-ended on a tree by the method prescribed in Section 60 and shown in Fig. 33. The main line should be held by a crosstie and the connection between the branch and the main line made with a piece of No. 14 insulated copper wire attached as shown in Fig. 40. In order to facilitate separation of the branch from the main line, a method of installing a switch when making such a connection is illustrated in this figure. 2 — TYPES OF INSTRUMENTS Where a Forestry Branch line is to connect with another line, either directly or by switches,. the resistance in ohms of the ringer coils in the instruments (and exten- sion bells, if used) should be the same as the resistance of those on the connecting line. The standard resistance of all ringer coils on exclusive Forestry Branch lines will be 2500 ohms. However, in connecting with lines that use other resistance ringer coils, it will be necessary to use the same resistance coil in instruments on the Forestry Branch line. Where telephones of other resistance than that specified are needed for use, the district inspector should be consulted as to the proper set to purchase. 79211— 6^ 84 METHODS OF VOMMUNICATTON FOR FOREST PROTECTION /^Copper wire soldered _, turns of f copper tv/re so/c/ered. ^Branch strain insulator. fastened with 3 "* to F. H. wood screws . No. 14- Rubber- covered, braided and weather-proof tw'sted >v/>e. S.PS.T. Knife-switch ploced 6 ff. above ground. Out of door, met hod of affachtno; branch //nes /o rna/'n //'nes .' Where trees suppor-t the //nes, c/eacf-eno/ as shown 6v • r/g.33 • r?un the branch /ine to the main fine, dit-ecf/y from the hanger. The rna/n /me shou/o/ be fastened fo a standard anchor. Run copper wire through ho/e in strain jnsu/ot~or for support: Fig. 40 Method of connecting branch to main line in tree construction CHAPTER XII INSTALLATION OF FIXED EQUIPMENT Section 69— Wall Sets The standard wall telephone set will always be the most common type employed. It is used for nearly all permanent indoor installations, except at lookouts or main headquarters, where desk sets are desirable. The sets as received from the maker are in a partly "knockdown" condition and must be assembled. This consists of putting in place the receiver, transmitter, shelf, and generator crank. Suitable screws are pro- vided, where needed, and holes bored for them. Directions for assembling accompany each set, as shown in Fig. 41. The location of the instrument inside the building will always be determined largely by convenience in using it. This location should be decided upon, however, before the line wire is brought up to the building. It is customary to stand up when using a wall set, and the height of instrument must be determined accordingly. Instruments must not be attached to walls with nails. Use the four If-in. No. 10, round-head, blued screws provided, and make Certain that the screws get a sufficient hold on the wall to support the weight of the set and the extra weight of persons leaning on the shelf. Instru- ments installed in unlined log buildings should be attached to a suitable board and this in turn fastened securely to the wall. Always try to place the instrument so that it will be directly over the point of grounding. Each standard instrument when received should have pasted to the inside of the door, a diagram of the internal wiring and complete directions for setting up and connecting to the line (see Fig. 41). It is to be noted that the wires from different parts of the set are variously coloured and these colours are indicated on the simpli- fied diagram, making it easy to identify various circuits in the set itself. The two terminals on the right-hand side of the instrument marked Ll and L2 are the ones to which the .line wire and ground wire respectively must be connected. [In some older types of instruments on a few reserves these terminals are -on the left side of the box. The diagram, however, will indicate connections.] On a metallic circuit connect one of the wires to each of these terminals. The terminal marked GND is not used at all in the set as employed on Forestry Branch lines. Section 70 — Condensers The condenser in a telephone is cut in circuit in series with the receiver. It makes possible "through" signalling when receivers at intermediate stations are off the hooks. Any telephone now in use, if not already provided, can be equipped with a condenser. The condenser may also be cut in on one side of the ringers for testing purposes. Section 71 — Dry Batteries 1 — INSTALLATION Three dry cells are required for all instruments except the lookout sets and the portables. Northern Electric, Blue Bell, Blue Label, or Columbia cells are recom- mended and those with Fahnestock clips are to be preferred to those with the common binding-post. C'onnect together as shown in Fig. 43, using insulated stranded wire rather than solid wire, since it is more pliable. Do not remove the paper cartons which are needed for proper insulation and take care that the adjacent zinc binding posts do not touch. 85 86 METHODS OF OOMMUNWATION FOR FOREST PROTECTION LINE-l GND. LINE-2 ORANGE; YELLOW GREEN BATTERIES NOT FURNISHED WITH THE SET Fig. 41 Wiring- diagram and directions for assembling standard wall telephone set Tools. — An ordinary screw-driver is the only tool that is required for all adjustments and wire connections. This set is shipped connected for service on either metallic or grounded circuits with the red ringer lead to terminal " Line 2," the black ringer lead to terminal " Line 1," and when there is no condenser, the yellow receiver lead to lower " cond " terminal. When used on metallic line circuits, connect one line wire to terminal " Line 1 " and the other line wire to terminal " Line 2." When used on grounded circuits, connect the line wire to terminal " Line 1 " and the ground wire to terminal " Line 2." When used for divided ringing, that is ringing from either side of a metallic line to ground, connect the red ringer lead in one group of sets to terminal " Line 1 " and in the other group to terminal "Line 2." In all sets connect the black ringer lead and the ground wire to terminal " gnd." The tip side of the central office line to terminal " Line 1 " and the ring side to terminal " Line 2." To connect the condenser in series with the receiver. — If not already so equipped, connect the yellow receiver lead and one condenser lead to the upper " cond." terminal, and connect the other condenser lead to the lower " cond." terminal. To connect the condenser in series with the ringer (when the set is used in connection with common battery lines). — Connect the red ringer lead and one condenser lead to the upper " cond." terminal, the black ringer lead to terminal " Line 1 " and the yellow receiver lead and the other condenser lead to the lower " cond." terminal Ringer adjustment. — The armature shall be so adjusted that the clapper ball has a move- ment of about Vir, inch. To obtain this, turn the screw " A " to the right to shorten the stroke, or to the left to lengthen the stroke. The gongs should be so set that the clapper ball strikes but does not rest against them when thrown to either side. To change position of the gongs, loosen the clamping screws " B," turn the eccentric adjusting screws " C " until the correct position is obtained and then tighten the clamping screws " B." In mounting the transmitter, connect the cord " A " of the transmitter to terminal " C " inside of the door and connect the cord " B " to terminal " D " on the door. In connecting batteries, connect wire •" E " to post " F " and connect post " G " to " H " and "M" to "N" and connect wire "P" to post " R." See that the binding-posts " G," " M " and " R," do not touch each other when the batteries are in place. Repair parts should be ordered by sample if possible, otherwise by accurate description, always mention, if possible, the code number of this set (it is stamped on the inside of the door n^ar the bottom edge). INSTALLATION OF FIXED EQUIPMENT 87 Fig. 42 Standard telephone installation (a) Front view, (&) Back view, (c) Side view 2— RENEWAL Regular systematic renewal -of all batteries at least once a year is necessary. In some cases more frequent renewals will be required'. For such places the 3-in-l bat- tery, which consists of three cells inclosed in a waterproof casing with only two exposed connecting-posts, will often be found desirable as it has a. somewhat longer life. Batteries deteriorate rapidly whether in use or not. Two new batteries should never be installed with one old battery, nor one new battery with two old batteries, as one poor battery will spoil the efficiency of the good ones. Fig. 43 Method of connecting dry batteries for a telephone 88 METHODS OF COMMUNICATION FOR FOREST PROTECTION 3 — TESTING For battery testing an Ever Ready, No. 1003 battery gauge is a cheap and fairly efficient instrument, and each forest reserve headquarters should be provided with one. Cells which test less than 10 amperes should not be accepted. 'Cells showing less than 4 amperes at the end of a one-minute test should be discarded. First-class Blue Bell, Blue Label, or Northern Electric cells when new may be expected to show 14 amperes on test; Columbia, 24 amperes. 4 — REMOVAL FROM UNUSED STATIONS Always remove the battery from the telephone in stations that are to be left unoccupied over winter, also from all outdoor sets. If left in the instrument consider- able damage may result from leakage of chemicals. This is particularly true with the 1336-J set in which the battery is immediately adjacent to the generator. Section 72 — Protectors The question of protection is a very important matter and is divided into two classes in Forestry Branch work: (a) partially exposed substations and (Z>) fully exposed substations. Porce/ain tube sloping upwards from outside through wa/lofbui/ding as shown fi To //ne /er/n/nal\ of profecfor Protector [".] /nstde ofbui/ding Telephone set /*? B &S rubber covered bra/ded and wealherproofed *+/2Porce/a,n Knob C0flper "/re (Use insulated wire for ty/ng) Line *—£nd of /me w/re /eft fong enough after dead ending fo be brought back on rfse/f doi*n to fuse and grounds fhe/ron box -Scrape enornG'/ off fo in- sure cjood confacf~af/aq s when a 'riven /n ~f~/gftf~ /fc/esired ' fh/s af ground ferm/ no/ of protector instead ofatorvvnd rod as shown Ground ffocf Fig. 49 Method of connecting lookout station telephone to line and ground 79211—7 98 METHO'D® OF COMMUNICATION FOR FOREST PROTECTION To line Howler Condenser^ To be atfoched to wo /I pieces of leather and screws Lightning Protector Ground Fig. 50 Method of connecting howler and condenser Section 77 — Coils 1 — LAVITE COILS These coils are used to remove static electricity from the line. Each coil should have a resistance of 48,000 ohms, and be inclosed in a small weather-proof box. (See Section 93, Static Electricity) . It will generally be necessary to install these coils outdoors on poles along the line. The method of installation is illustrated by Fig. 51. 2 — KEPEATING COILS The standard 47-A repeating coil is generally placed indoors as part of one of the special installations described in Sectjon 78. In such cases no special precautions with regard to the placing or wiring of the coil are required, except to see that it is guarded by the protective devices in the same manner as the other apparatus and that the eight connections are properly soldered. In some cases the necessity arises for placing one of these coils outdoors. When this is required the coil should be placed near the top of a pole and the latter may be provided with pole-steps if desired. Coils should not be installed on trees. Two protectors will usually have to be placed between the coils and the lines, and the, whole inclosed in a waterproof box. The method of making such installations is fully illustrated in Fig. 52. INSTALLATION OF FIXED EQUIPMENT 99 Fig. 51 ^Method of installing Invite -coil to drain line of static electricity Section 78 — Special Installations It is possible under this head to discuss and illustrate only a few of the more common types of special connections encountered on forest protection lines. '//£/* 0 fhro* 3W/C/? U n n n Fig. 53 Legend (1) To enable calls to be received separately from the several lines which ter- minate on a switchboard. (2) To enable calls to be received in remote parts of a building or in other buildings at a distance from the telephone instrument. (3) To enable calls to be received outdoors at a distance from the telephone instrument. Each bell is provided with two terminals and is connected to the line in the same manner as a telephone instrument, that is, on a bridging line it is bridged between line and ground or between the two wires of a metallic circuit. Extension bells must always be protected from lightning and other high-tension currents, as are telephones. Extension bells with gongs of different shapes and tones may be secured and are used to make it possible to distinguish signals on different lines from each other. Where different tone bells cannot be secured^ the tone may be altered by placing a wire across the gongs or by sawing a small notch in one or both gongs with a hack- saw. 2 — MULTIPLE LINE SWITCHBOARDS It is frequently necessary to install switching stations on long lines in order to keep circuits down to workable lengths. These will usually be placed where a branch makes possible the separation of three lines. The switching method shown in Fig. 54 should be used where the three lines are not connected most of the time. It requires the following equipment : Two extension bells, one telephone set, and three single- pole, single-throw, baby knife-switches. With the three lines connected, two exten- sion bells and the telephone remain across the line. The method shown in Fig. 55 should be used where the three lines are connected most of the time. It requires the following equipment; Three extension bells, one 102 QPF ,31' COMMUNICATION FOR FOREST PROTECTION f ~], L— J ,3 -fJ 0O {., i-t. 00 £*:/e/?5/OS> 6<2// Fig. 54 Switching station, first met-hod oo Fig. 55 Switching stat.ori, second method INSTALLATION OF FIXED EQUIPMENT 103 telephone set, and three single-pole, double-throw, ba'by knife-switches. With all the three lines connected just the telephone remains across the line, the three extension bells being disconnected. When it is desired to receive buzzer signals at a switching station, each line must be separately .equipped with howler and condenser. Since it is impracticable to vary the tones of buzzers sufficiently to enable them to be distinguished readily one from another, it may be necessary to locate the various howlers in different parts of the room or building in order to be able to tell which line is calling. Mote Fig. co//, remove Wiring and connections on 47-A repeating coil oc/or new co//s. 3 — STANDARD REPEATING COIL The 47-A repeating coil is the most reliable and serviceable coil, both from a talking and signalling standpoint, and should be used wherever possible. This coil is also used for phantom work. By " phantom " i,s meant the utilizing of both sides of a metallic line as one wire. As illustrated in Figs. 57 and 87, an additional tele- phone circuit is thereby obtained. The repeating coil is also used whenever it becomes necessary to jom a grounded to a metallic line. An 8-A repeating coil is cheaper than the above and may sometimes be used for the latter purpose. The details of construction, and the arrangement and designation of terminals of the 47-A coil, are shown diagrammatically in Fig. 56. 4 — PHANTOM CIRCUIT It is possible under certaiji conditions to carry on two or more conversations simultaneously over the same telephone wire without interference. This is done by installing a phantom circuit, the most common type used in forest lines being ;=• grounded phantom out of a metallic rural line. The following equipment is necessary: Two 47-A repeating coils, one extension bell, and one double-pole, double-throw, baby knife-switch. By the method shown in Fig. 57, the Forestry Branch utilizes both wires for their line, the connection with th« 104 METHODS OF COMMUNICATION FOR FOREST PROTECTION Branch line being made at the end of the rural line circuit, thus eliminating the necessity of stringing an additional wire parallel to the rural line telephone circuit. By the use of the phantom circuit a direct line is obtained to the exchange or town where the rural line terminates without interfering with subscribers on the latter. The circuit is so arranged that the grounded Forestry Branch line may be cut on the metallic line direct through the 47-A repeating coil in an emergency. It is also To Co// Fig. 57 Phantom circuit arranged so that, should any of the ranchers desire to talk to one of the stations on the Forestry Branch grounded line beyond the point where the rural line terminates, by calling the station at the end of this line the switch at that point may be thrown and direct connection had. This phantom circuit can only be built up where the metallic line does not parallel any electric-light, power, high-tension, or railway wires. 5 — CONNECTION OF GROUNDED TO METALLIC CIRCUIT The necessity for making this type of connection frequently arises where the Forestry Branch lines are joined to private or provincial lines near forest reserve boundaries or at ranger stations, in order to give through service from points in the reserve to points outside. It sometimes arises, also, when Forestry Branch metallic circuits are constructed in order to eliminate inductive disturbances from power lines or other circuits in their vicinity. A method of installing a switching station where a grounded Irne may be cut through to a metallic line with a 47-A repeating coil in circuit is shown in Fig. 59. Equipment necessary: One 47-A repeating coil, two double-pole, double-throw, baby knife-switches, and one telephone set. This method is used where connection is necessary with some commercial toll line, one telephone being used on the commercial line and the other on the Forestry Branch line. If a subscriber of the commercial telephone company, or provincial line, is using the toll station, the call on the Forestry INSTALLATION OF FIXED EQUIPMENT 105 Branch line may be answered at the same time, thus avoiding delay or interruption. When it is necessary to connect the grounded line to the metallic line, both switches should be closed, only one telephone being left across the line. Fig. 58 Connecting grounded line to metallic line through a repeating coil without switches. Dotted lines indicate connections when an 8-A coil is used Fig. i59 Connecting grounded line to metallic line by use of switches and two telephones A method of connecting a grounded line to a metallic line so that either can be used with the same telephone is shown in Fig. 60. 106 METHODS OF COMMUNICATION FOR FOREST PROTECTION Equipment necessary: One 47-A repeating coil, two double-pole, double-throw, baby knife-switches, one double-pole, single-throw, baby knife-switch, one extension bell, and one telephone set. This circuit is arranged with one, telephone and signal bell, so that a person at the station may talk on either line by using the same telephone. The operation of the switches is as follows: Switch 1 closed down, switch 2 open, switch 3 closed — telephone on metallic line direct. Switch 3 open, switch 1 closed down, switch 2 closed down — telephone on grounded line direct. Switch 3 closed, Fig. 60 Connecting grounded to metallic line by use of switches and one telephone switch 1 closed up, switch 2 closed up — grounded line cut on to metallic line through repeating coil direct, instrument remaining across entire line. This circuit is so arranged that the instrument may be left on the grounded line and the extension bell will ring if a person at this station on metallic line is called. Switches 1 and 2 should never be closed down at the same time without opening switch 3, as by so doing the' metallic line would be made very noisy. 6 — SUPERIMPOSING TELEPHONE ON TELEGRAPH CIRCUIT It is readily possible to use a telegraph line either grounded or metallic for simul- taneous telephone service without interference, providing automatic sending-instru- ments are not being used on the telegraph circuit or on adjacent ones on the same poles. At least two distinct methods of superimposing are employed, each of which has several modifications affording a considerable number of different systems adapted to various conditions. It will usually be found that the object sought is to employ an existing telegraph line for forest protection telephone service, but since the exact system that must be used will depend in each case on the arrangement and character- istics of the telegraph circuit it will be necessary that each case be referred separately to the district inspector for instructions. When reporting to the inspector state the number of telegraph wires available, whether they are operated as grounded or metallic INSTALLATION OF TEMPORARY EQUIPMENT 107 circuits, the number and position of all telegraph stations on the line it is proposed to- use, the size and kind of wire and whether the telegraph operates by single or double current, simplex, duplex, quadruplex, or automatic. Telegraph Instrument _cT^ Battery -=- Jeleyraph Instrument f ^U- 00 00 Fig. 61 Method of using one wire for simultaneous telegraphy and telephony Bell signals cannot be employed on superimposed circuits so that most of the standard Forestry Branch telephone instruments cannot be used on such lines without modification. The 1004- A set which employs buzzer signals may be used, however. In the majority of cases the object will probably be to superimpose a grounded telephone circuit on a grounded single-current telegraph circuit. The telegraph employs direct current while the telephone employs alternating current. If, therefore, condensers are inserted between the telephone rnstruments and the line, there will be no tendency for the telegraph current to escape to ground through them, while on the other hand the alternating currents of the telephone are not of sufficient strength to affect the telegraph instruments. The simplest form of such a superimposition is shown diagrammatically in Fig. 61. CHAPTER XIII INSTALLATION OF TEMPORARY EQUIPMENT Section 79— Types of Portable Sets Portable telephones are used for two principal purposes. To a certain extent they are required for testing lines, both during construction and in maintenance opera- tions. Portable sets used for these purposes are usually known as " test sets." These are on the market in great variety, each type being adapted by the details of its con- struction to some particular class of work. Some of these sets are very low-priced and light in weight, but none of them meets successfully the special problems ordinarily encountered on forest protection lines. In. addition to their use for testing lines, portables are required in forest protection for establishing temporary emergency stations on or adjacent to the permanent lines of communication. The average conditions met with on forest telephone lines demand a portable set of considerable power, especially in the generator. This instrument must approximate the capabilities of the very powerful standard sets employed in the per- manent stations and must be adapted for use on lines with them. Furthermore, since 108 METHO'DS OF OOMMUNICATIOX FOR FOREST PROTECTION it must be carried frequently on pack-horses and saddle-horses and be subjected to rough field usage it is essential that it be self-contained and well protected against external injury. Finally, light weight is important. To meet these requirements it was necessary to design an entirely new -style of portable set. The 1375- A set of the Northern Electric Company was the result, and it has been adopted as standard by the Forestry Branch. No other type of test set may be purchased except with the approval of the district inspector. The weight of the 1375-A set, however, was still found to be a handicap to its use -by moving patrol, especially foot patrolmen, and a still lighter instrument was designed. This is the 1004-A set of the Northern Electric 'Company which weighs oTily 2* pounds with battery and may be carried in the pocket. It uses the military method of vibratory signals and has been standardized for use by the Forestry Branch. Finally, occasions sometimes arise when it becomes desirable to provide more com'plete telephone service at temporary stations than either of the above sets is capable of affording, but where extra light weight is not essential. As a rule this is accomplished by using a wall set, but obviously these are poorly adapted to rough methods of transportation. To meet this requirement a combination of certain standard equipment into a single set known as the Forestry Branch emergency set No. 1-A has been devised. These sets are not .available for purchase but may be assembled locally or secured from the district inspector. Section 80— Forestry Branch Portable Telephone 1 — USE IN FOREST PROTECTION The special portable telephone (Northern Electric 1376-A, Fig. 6<2) being adapted for use on any line employing code signalling by polarized bells lias a wide application in forest protection wherever its weight of 9 pounds is not a serious bar. It is more widely applicable than the Adams hand set herein described, although considerably more expensive, also. The particular .advantages that this set possesses are as follows : — * . (1) It is entirely self-contained in a stout leather case and capable of with- standing very rough usage. (2) It will call by bell signals any permanent station or any temporary station provided with bells. It will also call any station equipped only with a howler. (3) It is provided with a protector and, therefore, may be left connected to the line without fear of injury from lightning. (4) It is provided with a buzzer and, therefore within limits, may receive a signal from a distant station. (5) Although normally it uses only a small flash-light battery, it may, if desirable, be equipped with ordinary dry cells. These advantages are offset only by the weight and cost of the set, and' where the former is not very objectionable the set should be used. In general, portable sets are a useful feature of the equipment of rather highly specialized forces only. They presuppose the existence of a fairly well developed system of lines of 'communication and of time standards, which make it imperative that these lines be available for use by the field staff regardless of the location of per- manent stations. No telephone system can be provided' with permanent stations so numerous that considerable time will not be required to reach them from the average point along the line. Both cost and electrical load requirements restrict the number of possible stations very materially. Wherever, therefore, the average time required to reach a permanent station in order to send an emergency message is greater than the protection standards will permit, portable sets must be made a feature of the -equipment. INSTALLATION OF TEMPORARY EQUIPMENT 109 This set will be found particularly useful for railway-speeder patrol. It should be mounted on the speed'er in a suitable box and may be connected by a switch to the ignition battery. By the exercise of a little ingenuity a speeder may be -equipped for almost instant communication from any point 'along the line, and lire may be at once reported without -the necessity of running to the nearest station. The set is also well adapted to all sorts of repair and construction work and where travel is largely by team, as in many of the reserves of the Prairie Provinces, Fig. 62 Forestry Branch portable telephone set (1375-A) with ground rod and connector it will be found superior to any other for general use 'by forest officers. It is not, however, well adapted to either foot, horse, or canoe patrol, but may be employed on motor boats. 2 — CHARACTERISTICS OF 1375-A SET The weight of the set is 9 pounds and the outsidte dimensions 3£ in. by 6J in. by 9 in. It is contained in a sole-leather case and provided with an adjustable shoulder- strap. The interior contains an aluminium angle-plate to which is attached all the equipment except the receiver, transmitter, and switch. These are combined in a very light, compact, aluminium hand set. The angle-plate is itself fastened to the leather 110 METHODS OF COMMUNICATION FOR FOREST PROTECTION case by screws. A wooden block on top bears the two binding-post connections and' a spring clip in which the detachable generator erank is carried. Inside the lid of the leather case is a diagram of the connection (Fig. 63). The hand set is carried i small compartment alongside the rest of the essential apparatus and is connected per- manently to the set by a stout receiver cord. A small, black button at the receiver end must be pressed while using the set for talking or listening. This takes the place Fig. 63 Wiring diagram of Forestry Branch portable telephone of the switch-hook in the ordinary telephone. The 'battery employed is a three-cell, Hat, flash-light type, such as the 703 Ever Ready. This battery is inserted by remov- ing the two top screws on the side bearing the generator crank and .shoving the bat- tery in with the contact plates foremost. When it is desirable to use the ordinary type of dry cell with the set, one or two may be connected by insulated wires attached under the heads of the screws that fasten the battery contact springs located in the back of the battery, chamber. As the button on the hand set closes the battery circuit it is particularly necessary to be sure that it is not depressed by the receiver cord or case when the set is packed, as otherwise the battery will rapidly exhaust itself. The hand set is of very light aluminium and must be carefully protected against injury. Dents near the switch may make contacts that reduce or destroy the efficiency of the instrument. Section 81 — Adams Hand Set 1 — USE IN FOREST PROTECTION The necessities of the more highly specialized forest protection forces demand a type of instrument that may be available to every member of the field staff, regardless of the transport facilities employed. Experience has demonstrated that oiily an instru- ment that may reasonably be described as a pocket type will meet these requirements. When it is remembered that some of the more perfectly organized forces require hourly INSTALLATION OF TEMPORARY EQUIPMENT 111 reports from the field force throughout the danger season, this need will be readily appreciated. It has been successfully met by the invention of the Adams hand set (Northern Electric 1004- A, Figs. 64 and 66). Fig. 64 Adams hand set (1004-A) with carrying case and connector and grounding knife NOTE;- CONTACT AT A SHALL NOT BE MAOIWHEN'TALK BUTTO* 'S PRESSED. Fig. 65. Wiring diagram of the Adams hand set (1004-A) This hand set is so small aTid light that it is as conveniently carried as a fair- sized field-glass. In addition it is considerably less costly than the Forestry Branch 112 METHODS OF COMMUNICATION FOR FOREST PROTECTION portable telephone and compares favourably in this respect with the low-priced test sets. Its advantages, however, are almost wholly those of weight and price, but both are so considerably in its favour that it has a very wide application in specialized forest protection. The disadvantages 'of this set are as follows: — (1) It cannot be used to call a statio-n equipped with the standard instruments, unless an auxiliary signalling device is installed. (;2) It has no protective equipment and cannot safely be left connected to a line when not in use. (3) No means are provided by which a station equipped only with this set can receive a call. Auxiliary apparatus must be available. 2? — CHARACTERISTICS OF THE 1004^ A SET The weight of the set is 2'£ pounds and the length over -all is 9-| in. This set eliminates entirely the heavy, alternating-current generator needed for ringing the ordinary type of polarized bell by substituting an entirely different system of signalling, and thereby greatly reduces the necessary weight. Transmitter and receiver are the same as with the portable telephone and a larger, three-cell, cylindrical, flash-light battery is employed. A switch with two push-buttons is provided. One of these is pressed for signalling, the other while talking and listening. The novel feature of this set is the induction coil, which, besides serving the usual purpose in speech transmis- sion, also serves to produce a very rapidly alternating current, used in signalling in place of the generator and bells. This is accomplished 'by equipping the coil with a vibrator which makes and breaks a contact in the primary of the induction coil. The whole apparatus is inclosed in a special aluminium case and equipped with two binding-posts at one end for connection to the line and ground. The proper connections are designated L and G, respectively, on the sides of the instrument near the binding-posts, and it is important that the line and ground wires be attached to the right posts, as otherwise the efficiency of signalling is reduced. Calls are made by a system* of long and short buzzes. These are produced by depressing the button marked " 'Signal." After signalling, the " Talk " button is depressed to use the instrument for conversation. Long conversations with the portable must be avoided as the longer the conversation, the greater the drain on the battery. The batteries should last with ordinary usage six or eight weeks and care should be taken to see that fresh ones are secured for renewals. The Ever Ready Tungsten No. 705 is the type employed. When inserting a new battery in the battery chamber it is necessary to put the top of the battery in first, so that the spring of the battery chamber cap has the broad surface of the bottom to bear on. The signals from this set are received by a howler. The installation of this apparatus has been described in Section 7'6. The instrument itself is described in Section 86. The presence of a number of howlers on the line is objectionable for not only do they produce a disagreeable noise when a signal is sent in either by generator or vibrator, but all conversation on the line is audible in any room where a howler is placed. Howlers should be installed only at the principal switching centres or at such stations ,as are most continuously occupied. Ordinarily they should be at least 30 miles apart and may be at greater distances. Any station not equipped with a howler may be called with the usual bell signals through one of these switching centres. In using the Adams hand set it is necessary to keep in mind that it is entirely unprovided with a protector and, also, that when it is connected to the line it acts as a direct ground. It should, therefore, not be left connected to any line when not in use, as it would not only be exposed to serious injury from lightning but would prevent other stations from ringing past it. It should also be noted that the sound of the vibrator when received in an ordinary receiver over lines of ordinary length is not INSTALLATION OF TEMPORARY EQUIPMENT 113 only painful but might be dangerous to the ear. 'Special precautions must always be taken to make sure that the line is not in use before attempting to call a station with this hand set. The aluminium case is thin, and dents or other injuries which it might receive from rough handling can easily form contacts that may destroy the usefulness of the set. These must be carefully avoided and the sets must always be transported in the leather cases furnished with them. These cases are made large enough to hold the necessary connectors and a folding ground rod. m Fig1. 66 Forest officer preparing to use the Adams hand set with Cree knife for ground rod 3 — BUZZER SIGNALLING The vibratory currents produced by the Adams hand set are of very high-tension and will traverse lines that are in such poor condition that bell signals will not pass over them. It is therefore feasible, when lines for any reason are in extremely poor condition, to call stations with this set at much greater distances than with the bells. It is even possible to signal across breaks in the wire providing the ends of the broken wire make a good ground contact, preferably with moist earth. In this case, however, signals cannot be heard in the howler but can only be heard in a receiver held to the ear, which restricts the practical utility of this capacity to those few forests that maintain permanent telephone operators with head receivers. Tests have shown that signals are plainly transmitted across a 65-ft. gap and may be distinguished very faintly across a 210-ft. gap. They will also traverse miles of bare iron wire lying on the ground, even in wet weather, and at a distance of one mile may be heard in the howler. The sound produced in an ordinary receiver at a distance of 50 miles over very poor lines can be heard several rods away. At a distance of 200 miles over lines too poor for transmission of speech, signals are plainly audible in the receiver when held to the ear. and weakly audible in the howler. 79211—8 114 METHODS OF COMMUNICATION FOR FORE 1ST PROTECTION This capacity for very long distance transmission over poorly insulated or even broken lines makes it feasible to consider the set as a possible auxiliary communication device for sending telegraph messages, even when the lines will not carry telephone messages. This buzzer telegraphy is the most common method employed for military communication over field cable and other insulated- wire lines laid on the ground. The International Morse code is used and dots and dashes are represented by short and long buzzes. The Adams hand set would require some modification if used in this way to' any considerable extent, but there are possibilities for utilizing it in emergencies wherever the protection forces have the requisite training and organization. It is also to be noted that the buzzer signals of this set may foe transmitted simultaneously with ordinary Morse signals over one wire (see 'Section 78). Section 82 — Emergency Communication Kits 1— USE IN FOREST PROTECTION It frequently happens that temporary telephone stations must be established in the field, as at fire-camps and other camps where messages must be received as well as sent. The Adams hand set alone cannot receive a call, while the sound of the Fig-. 67 Forestry Branch emergency communication kit No. 1-A buzzer in the Forestry Branch portable telephone is inaudible at a few yards. Either a howler or an extension bell must be provided where signals are to be received. Communication kits comprising the necessary instruments for two stations with emergency wire and tools for stringing it, all packed into suitable cases for pack or wagon transport, are employed by certain protective organizations. A somewhat similar kit comprising the instruments above mentioned has been devised for Forestry Branch use. It is only necessary to add a case of emergency wire and a reel to this kit to have a full emergency outfit. INSTALLATION OF TEMPORARY EQUIPMENT 115 2 — CHARACTERISTICS OF THE 1-A SET The purpose of this set is to afford a field instrument that is self-contained, will stand rough usage, receive both buzzer and bell signals, and be available for use with either of the two standard portable telephones. In addition, space is secured for the grounding and connecting devices, extra battery, and some small installation tools. The 1-A set is a shallow wooden box divided into two compartments of unequal size. In the smaller compartment is mounted the following standard equipment: 1 extension bell, 1 protector, 1 howler, 1 condenser. The larger compartment is fitted with two binding-posts, from which wires lead to the external connections on the set as shown in Fig. 68. rL /ne Prole do Connect a /Z75-A or IOO4--A portable telephone of binding posts A and B Ground) time g> Fig. GS Wiring diagram of the No. 1-A kit It is arranged so that either the 10'04-A or the 1375-A portable telephone may be placed in it, connection being made to the above-mentioned binding-posts. Plenty of space is left in this compartment for tools, connectors, etc., and a' suitable holder provided for the ground rod. On the top and ends strong leather handles are attached by which it may be lashed to a tree or other support as shown in Fig. 69. This set weighs 26 pounds complete with all equipment, including the 1375-A telephone. With the 1G04-A set it weighs 19^ pounds. It may be placed on a table or other suitable support if used indoors. The doors open downward and serve as a writing shelf. Section 83 — Temporary Connections to Permanent Lines The method of connecting emergency wire to permanent lines has been described in Section 62. It frequently becomes necessary to make rapid connection with over- head wires from the ground. Such connection must be made, for instance, when cutting in on the line with any of the portable telephones previously described, and it is essential that both connection and disconnection be made quickly without the necessity for climbing poles or trees. To accomplish this some special apparatus has been devised. 1 — EMERGENCY CONNECTORS • The type adopted by 'the Forestry Branch consists of two pieces of No. 18 stranded, insulated wire, one of which is 25 ft. long and the other 8 ft. The former is provided 79211—81 116 METHODS OF COMMUNICATION FOR FOREST PROTECTION with a flat, brass hook at one end and a cord terminal at the other. The latter has a cord terminal at each end. The total weight is 10 ounces. For use with the Adams hand set a similar connector may be made in the field 'of emergency wire. A brass hook is easily improvised from the contact plates of a worn- out 703 Ever Ready battery. Fig. 69 Forest ranger using the No. 1-A emergency kit The emergency connector, Northern Electric No. 311-D, used 011 some reserves, is not as suitable as the new type, and this connector is no longer a, part of the standard equipment. 2 — METHOD OF USE The No. 311-D connector is joined to the overhead wire by throwing one end over and then pulling it along the wire until a contact is made at the bare place in the centre of the connector. The two ends are both joined to the line terminal of the set marked L. The short wire is then used to join the ground termmal marked G to the ground rod. The standard connector is attached to the overhead wire by means of a short pole. Generally, any light pole about 10 or 12 ft. long, cut as needed, is sufficient. To the tip the end of the connector bearing the hook is attached, so that the hook projects a few inches above the pole and the rest of the connector is wound around the pole in a long spiral. It is then hooked over the wire and allowe,d to swing loose, the weight of the pole serving to ensure a good contact The end bearing the cord terminal is joined to the line post of the instrument, the short wire connects the ground post to the ground rod. The whole operation is performed in a couple of minutes. With metallic circuits two connectors must be used, but the ground wire is unnecessary. 3 — TEMPORARY GROUNDS The importance of extreme care in locating permanent grounds has already been emphasized. Ear less care is required for a temporary ground connection. Although it is true that except in very dry regions, or in the winter in the north, a workable ground for a temporary connection can be ebtained almost anywhere, yet it is always THE MAGNETO TELEPHONE 117 best to let the grounding facilities determine the place of connection if possible. The best place is the margin of a stream, pond, or slough, where the ground rod may be set in the wet soil or mud. Do not try to ground in water alone, or in a Tocky bottom. If a natural wet place is not convenient, ground in loose, moist soil and after setting the ground rod pour a pail of water over it The special portable ground rod, Northern Electric No. 313-B, usually known as the bayonet ground rod (Fig. 62), is useful with emergency kits, but for use by patrolmen with portable telephones it should be replaced by a large hunting-knife. The bayonet rod is a singularly useless instrument except for its one special purpose, and when weight is an important consideration, as with patrolmen or " smoke chasers," the hunting-knife is preferable. A fairly large blade is necessary in order to make a good ground. At the base of the blade close up against the handle a brass binding-post should be inserted and soldered to the blade. The Cree knife shown in Figs. 64 and 66 has a blade 9 in. long by 2 in. wide and serves admirably for grounding a portable telephone, but a smaller knife may be used. Very good ground rods -can be made of heavy jointed brass rifle cleaning rods, and these may be car- ried in tne case of either of the portable telephones. It is probable that the need for a satisfactory portable ground will result in development in this direction. CHAPTER XIV MAGNETO TELEPHONE Section 84 — Introduction It is a matter of common knowledge that the purpose of the telephone is to enable conversation to be carried on between two persons who are beyond ordinary talking distance from each other, and that this is accomplished by converting the air vibrations of the voice into electrical vibrations which are carried to the distant person over a wire or electrical conductor and there converted into air vibrations or sounds of the same character. The modern commercial instruments have been brought to such a high state of perfection and are so nearly " foolproof " that it is possible for persons entirely without knowledge of the principles on which these instruments operate to install and use them with entire success by observing a few simplo precautions, following directions, and using plain common sense. It is very desirable, however, that those who have charge of extended telephone systems, such as are now commonly used in specialized forest protection, should have some under- standing of the fundamentals of the telephone. Unfortunately, to understand the operation of this instrument requires some knowledge of practically every branch of electrical science, because nearly every branch is to some extent utilized in the modern telephone. For the benefit of those desiring a full understanding of this instrument a comprehensive list of books of reference has been inserted in Appen- dix B. The description of the telephone instrument contained in 'this manual is intended •for those who have little or no knowledge of the science of telephony, and should be regarded only as an introduction to this science. It is necessary, however, to assume the possession of a knowledge of the funda- mental electrical phenomena. Those unacquainted with even the elementary facts of electrical science will first have to consult some standard text booK oil the subject. Certain definitions, however, of technical terms most frequently employed in the s-cience of telephony may assist in an understanding of the text, and are therefore included in this manual. 118 METHODS OF COMMUNICATION FOR FOREST PROTECTION Section 85 — Definition of Electrical Terms (a) Voltaic Cell. — A voltaic cell is an arrangement of two electro-chemically dii> fereiit solids in a liquid which will attack one of them more actively than the other. This liquid is called the electrolyte and is generally an acid. One of the solids is nearly always zinc. Carbon is very commonly the other. Dry voltaic cells usually consist of a zinc cup containing a carbon plate and an absorbent porous substance saturated with the liquid electrolyte. This cup is sealed with wax or asphaltum. Dry cells are now commonly employed to furnish the current for the transmission of speech by telephone. Inert dry cells that contain all the necessary elements except water may be o'btained. They are entirely inactive until water is added and keep indefinitely, while the ordinary type deteriorates rapidly even though not in use. (fr) Conductor. — Any substance through which electricity flows readily is called a conductor. Most metals are good conductors. In conductivity, copper is surpassed only by silver and is followed by aluminium, zinc, iron, tin, lead, and carbon in the order named. Iron has only about -one-sixth the conductivity of copper. (c) Insulator. — Any substance through which electricity will not flow readily is termed an insulator. " Non-conductor " or " dielectric " are other terms having the same meaning. Among common insulators are ebonite, glass, resins, paper, paraffin, porcelain, mica, rubber, and dry *air. " Conductor " and " insulator " are, however, relative terms. No substance is an absolute insulator and all substances oppose some resistance to the flow of electricity, so that no substance is a perfect conductor. (d) Circuit and Grounded Circuit. — The entire path along which electricity flows is called a circuit. It comprises the voltaic cell or cells called a battery or some other device, such as a generator, for producing electrical pressure, and the wire or other conductor connecting the battery plates or the ends of the generator coils. Bringing the two extremities of the wire in contact and separating them are called, respectively, closing and opening, or making and breaking, the circuit. A complete metallic circuit is unnecessary, it being possible to use the earth itself as a return path for the current. It acts more like a great reservoir of electricity than as a conductor. A circuit, part of which consists of the earth, instead of being a complete metallic path, is called a grounded circuit. (e) Magnet. — A magnet is a piece of iron or steel (generally a bar) which has the property of attracting other pieces of iron or steel. If freely suspended at it? centre it will point north and south. It can impart these properties to another piece of iron or steel without losing any of its own. These powers may also be -imparted to a piece of iron or steel by passing an electric current through an insulated wire wound around the iron or steel. Steel will retain these magnetic properties; very soft iron will retain practically none. An iron magnet thus produced is called an electro- magnet. (/) Electro-motive Force — The Volt. — That force which maintains or tends to maintain a current of electricity through a conductor is called electro-motive force. The abbreviation for this term is E.M.F. Electro-motive force is, in effect, electrical pressure and is analogous to the " head " or pressure which maintains a flow of water through a pipe from one vessel to another at a lower level. Electricity flows in a con- ductor only when there is a difference of such electrical pressure or difference of "potential" between its own ends. Such a difference may be maintained by a voltaic cell or t>y a generator. It is this difference of pressure which sets up a current in the conductor, and as long as it is maintained the current will continue to flow. The unit of E.M.F. is the volt, for practical purposes, about the E.M.F. of a Darnell's cell, i.e., it is about the difference of potential between the zinc and copper plates of this cell. THE MAGNETO TELEPHONE 119 (g) Resistance — The Ohm. — The opposition offered by any substance to the flow of the electric current through it is known as resistance. Different substances oppose the flow of electricity in different degrees, copper being one that opposes a very low resistance (see Conductor). Insulators oppose an immensely powerful resistance. With any given conductor, increase in length causes increase in resistance; increase in cross sectional area causes decrease in resistance; and, for most conductors, rise in temperature causes increase in resistance. For any one conductor, resistance is, in a way, analogous to the frictional resistance offered to the flow of water through a pipe. Electro-motive force tends to maintain a flow of electricity against the electrical resis- tance of a conductor just as a "head" of water tends to maintain a- flow of water against the frictional resistance of a pipe. The unit of electrical resistance is the ohm. Conductivity is the opposite of resistance. (/&) Current Strength — The Ampere. — The rate of flow of electricity is termed its current strength. It is the result of E.M.F. acting through a conductor and over- coming resistance, and is measured in amperes. The ampere, or unit of current strength, is analogous to the " miner's inch " used in the measurement of the flow of water. Obviously the three factors, E.M.F. , resistance, a id current a:-e interdepend- ent. Their relation to one another is stated in Ohm's Law thus : — The Current is equal to the Electro-motive force divided by the Resistance, or E 0 = - R (*') Electro-magnetic Induction. — Every magnet and every current-bearing wire is surrounded by a magnetic field having among other properties that of being able to induce magnetism in a piece of iron or steel placed within it, and of being able to produce a difference of potential between the ends of a wire moved across such a magnetic field in such a way as to cut its lines of force. If the ends of this wire are connected outside the magnetic field, a current will flow as long as motion is main- tained. Such currents are called induced currents and the process by which they are produced is called electro-magnetic induction. (j) Induction Coil.- — An induction coil is a device consisting of two distinct coils of insulated wire, one placed around the other, but not electrically connected, by means of which, as a rule, currents of low potential and high amperage are changed to a high potential and low amperage, or vice versa. One of the coils, usually having an iron core, is used to produce the magnetic field by means of a current from a battery to which it is connected. This is called the primary. The other coil, generally above the primary or around, it, is called the secondary. Currents may be produced in the secondary by means of any of the following methods : — (1) By moving either the primary or the secondary while a current is flowing in the primary, thereby altering the position of the coils with respect to each other. (2) By making or breaking the primary circuit. (3) By altering the current in the primary. (4) By reversing the direction of current in the primary. (5) By moving the iron core while current flows in the primary, thereby altering the magnetic field. Any one of these operations causes a disturbance in the magnetic field as a result of which currents are induced in the secondary. In the induction coil, as usually employed, either alternating or interrupted currents in the primary induce currents in the secondary whose E.M.F. bears the same relation to the E.M.F. of the primary current as the number of the turns of wire in the secondary coil bears to the num'ber of turns in the primary. For example, if there 120 METHODS OF COMMUNICATION FOR FOREST PROTECTION are 10 turns in the primary and 100 turns in the secondary and a current of 1 ampere at 10 volts pressure is passed through the primary, then the current induced in the secondary will have a pressure of 100 volts but a current strength of only 0-1 of an ampere. This principle is made use of in telephone transmission, in induction tele- graphy, and in wireless. (&) Electro-magnetic Generator. — The electro-magnetic generator is a device by which induced currents are -produced continuously and made to now through an exterior closed circuit. The dynamo generator consists of a magnet to produce a magnetic field, and a coil of wire wound on an iron core, which latter part is called, the armature. The armature is that part of the circuit in which the induced current is generated. If moved in the magnetic field of the magnet in such a way as to cut its lines of force, a current is produced by induction, and if the motion of the armature is continuous the current that results is continuous also. Electro-magnets are usually employed to produce a magnetic field but in some small generators permanent steel magnets are used. Such generators are called magnetos and being extensively used in certain types of telephones have given rise to the term " magneto telephone." (Z) Direct Current and Alternating Current. — The electric current among its other properties has direction. This has already been indicated in referring to the production of induced currents as in an induction coil. A current which moves continuously in one direction only is called a direct current. Such a current is that which flows from the carbon pole to the zinc pole of a voltaic cell when these are con- nected by means of a conducting material, such as a piece of copper wire. The current used in ordinary telegraphy is a direct current. As contrasted with this form of current we have that which is constantly changing in direction, flowing first m one direction and then reversing and flowing in the other. This is known as an alternating current and is produced by many forms of dynamo generators and in the secondary of an induction coil. Alternating currents are especially important in tele- phone work as both the talking currents and those which operate the common type of polarized bell are of this character. So also, is the current which actuates the howler used in vibratory signalling. (m) Frequency. — This term is used to designate the rate of reversal of direction of alternating currents. High-frequency currents are alternating currents that reverse direction very rapidly, while low-frequency currents reverse comparatively slowly. (n) Tension. — This term as applied to electricity has the same meaning as potential difference or E.M.F. High-tension currents are those of high voltage or E.M.F. (o) Electro-static Induction. — An insulated conductor, such as a sheet of tin-foil, has the property of receiving a charge of static electricity when subjected to an E.M.F., as, for instance, if it is connected to one pole of a cell, the other pole being connected to the ground. The charge that it receives is of the same polarity as the terminal of the cell to which it is connected and the amount of electricity held depends upon the capacity of the conductor. At the same time it is always found that when a conductor is charged as above described, an equal charge of opposite polarity is induced on the bodies surrounding it. If two sheets of tin-foil, for instance, are insulated from each other by means of a sheet of mica and one of them is charged as above, the other will be found to have an equal charge of opposite polarity. This action by which bodies are charged through an insulating medium is called electro-static induction. (p) Condenser. — -A condenser is a device for storing static electricity. It consists of two insulated conducting bodies separated from each other by an insulating material. The common form of condenser used in telephone work consists of sheets of tin-foil separated by sheets of paraffin-paper. However, any two insulated bodies, as, for instance;, two parallel wires or a single wire and the surface of the earth, or the TEE MAGNETO TELEPHONE 121 metallic conductor in a submarine cable and its protecting armour, act as condensers and have a certain capacity or ability to receive an electrical charge depending on their area, nearness together, and the character of the insulating medium between them. Condensers act as a complete bar to the passage of direct currents. Alternating cur- rents, however, will produce through a condenser the same effects as would be produced were the condenser not in the circuit. This results from the inductive effect between the plates of the condenser, and while there is no actual passage of the current through the condenser the results produced where alternating currents are concerned are the same as though the condenser were not in the circuit. The effectiveness of this action, however, depends upon the frequency of the alternations and the capacity of the condenser. High frequency arid large capacity produce better results than the opposite 'properties. (#) Wire Measure, the Mil. — The mil is the unit of measurement for the cross- section area of wires. It equals one one-thousandth of an inch (Hooo or -001 in.) The circular mil is used as the unit of area for circular wires and the square mil for rectangular conductors. Section 86 — Parts of the Magneto Telephone. A magneto telephone instrument such as is used on forest lines consists essentially of seven parts, as follows: — 1 Receiver 4 Induction coil 6 Ringer 2 Transmitter 5 Generator (magneto) 7 Switch-hook 3 Battery. To these are generally added a condenser wired in series in the receiver circuit, and the whole is inclosed in a wooden case and wired with insulated copper wires. Various accessory equipment is also employed. The more important of these accessories are described in a following section of this chapter. JL — RECEIVER The first of the distinctive parts of the modern telephone to be invented was the receiver. This was the invention of Prof. Alexander Graham ,Bell. For a time it was the only one of the distinctive portions of the modern telephone employed, and served as both transmitter and receiver. It exists to-day essentially as first invented, though many minor modifications have been made in its construction, and it has ceased to be regularly employed as a transmitter. The common bipolar receiver consists of a horseshoe-shaped permanent magnet, to each pole of which is attached a soft iron core, around which is placed a winding of fine insulated wire. Both coils are joined in series and the two ends of the wires are brought to binding-posts within or at the base of the shell to which the receiver cord is attached. A small, thin, circular iron plate or diaphragm is held at a distance of -015 in. in front of cores of the magnet coils and the whole is inclosed in a hard- rubber case. The receiver when used as a transmitter is essentially a miniature dynamo. The vibrations of the diaphragm, caused by the sound waves that impinge upon it, pro- duce disturbances of the magnetic field surrounding the poles of the permanent mag- nets and thus generate minute currents in the coils which flow out over the line and cause similar disturbances in the magnetic field of the magnets at the other station. These, in turn, produce vibration of the diaphragm similar to those that produced the currents1 originally, and these vibrations cause sound waves which reproduce the sounds made in the first instance. The currents that may be produced in this way, however, are extremely minute and have not sufficient pressure to operate success- fully over long lines of high resistance. The receiver, therefore, is not ar efficient 122 METHODS OF COMMUNICATION FOR FOREST PROTECTION , fit Fig. 70 Bipolar hand receiver Fig. 71 Longitudinal section of bipolar receive!' Fig. 72 Diagram of telephone circuit, first stage TEE MAGNETO TELEPHONE 123 transmitter. It is immensely sensitive to small currents, however, being in this respect one of the most amazing instruments that has ever been produced. As an instance, it may be stated that experiments have shown that the work performed by a weight of only one pound falling through a vertical distance of one foot would involve sufficient energy to maintain an audible sound in a receiver continuously for about 250,000 years. In its most primitive form, therefore, a telephone consists simply of two receivers joined together by a wire of some conducting material, as in Fig. 72. This largely explains 'how, as most operators of telephone circuits have learned, speech may often be transmitted through the receiver of the ordinary instruments when the transmitter itself is out of order. The modern receiver is an extremely simple instrument and almost immune from serious injury. Only gross carelessness can result in a broken shell or bent diaphragm, and this is generally the extent of any damage to a receiver. Only very rarely do the coils become burned out by lightning, or the permanent magnet become unduly weakened through loss of magnetism. The receiver cord by which it is connected to the telephone may cause trouble. It must be extremely flexible, and is therefore made of insulated tinsel wires. These sometimes. break, especially where they join the tips, thus introducing a fault into the circuit. 2 — TRANSMITTER The limitations of the magneto telephone as a transmitting instrument soon started investigators working on the production of a more efficient transmitting device. The need of a stronger current than can be generated by the magnetic field of the Bell instrument was apparent, and the solution was found in the modern carbon microphone or transmitter. This instrument is based on the principle early set forth by Du Moncel that, " if the pressure between two conducting bodies forming part of an electric circuit be increased the total resistance of the path between them will be diminished, and if the pressure be decreased there will be an increase in the resistance." Other investigators showed that a loose contact was an important feature in securing the necessary variations in resistance to cause variation in current, so that the problem became one of contriving some device by which a conducting material forming part of the telephone circuit might afford a. loose contact, the pressure on which could be varied by the sound waves produced by the voice and thereby through the varying resistance resulting, vary the current through the con- ductor. This varying current passing out over the line to a distant receiver would cause corresponding variations in the magnetic field surrounding the cores of the receiver magnet coils', and these in turn acting on the receiver diaphragm would cause it to vibrate and thus produce sound waves similar to those originally produced by the voice. It was further discovered that, of all conductors, carbon was the one in which slight variations of pressure produced the greatest effect on the current. Carbon was, therefore, adopted as the material out of which to make one or both of the electrodes which formed the loose contact in the circuit. In the magnetic telephone no battery is required but, as previously explained, the currents produced are extremely minute. With the microphone in the circuit, a battery may be employed and a current of much greater strength obtained. This current, the microphone, through the loose contact of the carbon electrodes, varies according to the varying pressures produced by the sound waves, and as the strength of the current varies, so also varies the tension between the diaphragm and receiver magnet at the distant station whereby the diaphragm is caused to vibrate and repro- duce sounds as- previously explained. The transmitter most commonly employed in America and the one used on the Forestry (Branch standard equipment is known as the White or " solid-back " transmitter and is shown in Figs. 73 and 74. In this 124 METHO'DS OF COMMUNICATION FOR FOREST PROTECTION transmitter two carbon disks are employed! between which is a quantity of carbon granules. To one of these disks a light metal diaphragm is attached. This diaphragm is caused to vibrate by the sound waves impinging upon it, thereby varying the pressure Pig. 73 Solid-back transmitter and transmitter arm Fig. 74 Details of the solid-back transmitter Line 1 p Trans • 3 ||||_^ dtdW *3Ilr (J UJ Trans. r// Fig. 75 Diagram of telephone circuit, second stage on the carbon granules between the two carbon disks. The transmitter is so wired that these disks and the granules between them are in the battery circuit. The vary ing- pressure, therefore, causes variations in the current which in passing through a receiver reproduces the sounds of the voice. THE MAGNETO TELEPHONE 125 The next step, therefore, in the development of the telephone circuit consisted in th.e introduction into it of a voltaic battery and a carbon microphone or transmitter as shown in .Fig. 75. The back electrode B is a small metal case held to the support A by a lock screw. It carries in it the metal plate :C, which bears a carbon face. Over this is a similar plate D and between the two is placed a quantity of carbon granules. The plate D carries the screw-threaded bars E and G. Over these fits the mica washer F, the nut IT, and the screw-cap I. The bar G projects through the vibratory diaphragm J, which is held in place by the nuts S and S. The transmitter is perhaps the .most delicate portion of the modern telephone set. It is readily burned out by atmospheric electricity, and the carbon granules sometimes pack together, especially if they become damp, thus interfering with transmission. Xo one but an expert instrument man should ever undertake to repair an injured' trans- mitter. 3 — BATTERY For telephone service what is known as an open-circuit cell is preferred as a source of electric current for talking purposes. As a rule a battery of two or three such cells is used. It might seem that transmission could be improved by the use of a very strong current, but the difficulty arises that such currents heat the carbon contact in the transmitter, and, in time, ruin it. For this reason low-resistance, low-voltage batteries are preferred. Open-circuit cells are those which have the power of recuperating through depolarization whenever the circuit is left open. They are not suitable for prolonged continuous use, as are closed-circuit cells, which work best when in constant use. As will be later explained, the talking circuit of a telephone is always open except when the telephone is in use or the receiver off the hook and, therefore, open-circuit cells are the best for this service. The greater convenience of dry cells has led to their general adoption for telephone purposes. These are in all respects like ordinary cells except that the liquid solutions are mixed with some absorbent material and so rendered practically solid. There is thus little danger of liquids spilling or leaking out and causing damage. At the same time this danger is not entirely absent and batteries should never be carried in telephone sets, especially when lying on their sides. In this position, if there is any defect in the shell of the battery, some of the contents may leak out and corrode the wiring and other metal parts with which they come in contact. Dry cells, of course, become exhausted in time and must be renewed just as do other forms of primary cells. 4 — INDUCTION COIL The next important step in the development of the telephone after the invention of the transmitter was the introduction of an induction coil into the circuit 'by Edison. This, in fact, marked the beginning of practical telephone development, since, prior to the use of an induction coil, the range of transmission was extremely limited. Even after the transmitter was employed, it was found that the changes produced in the total line resistance by the varying pressure on the carbons were so small in comparison t< the total line resistance as to produce variations in the current that were scarcely per- ceptible in a distant receiver. The problem, therefore, was to arrange some means by which the voltage of the current going out over the line could be increased, other than by increasing the voltage of the battery, which we have already seen had limitations. It had further been noted that the telephone receiver was more sensitive to minut alternating currents than to the varying- direct currents such as had up to this been employed, but no means by which an alternating current might be employee been devised. 126 METHODS OF COMMUNICATION FOR FOREST PROTECTION The induction coil, as used in the telephone, accomplishes both of these objects. It is, of course, a fundamental factvof electrical induction that any change in a current in the primary winding of an induction coil, such as the opening or closing of the circuit, or the increasing or decreasing of its strength either by changing the voltage or the resistance, induces a momentary current in the secondary winding. These momentary induced currents are in 'the same direction as the current in the primary Pig. 76 Telephone induction coil Line flee Rec Battery Fig. 77 Diagram of telephone circuit, third stage when caused by a decreasing of the primary current, and in the opposite direction when caused by an increase in that current. Now the effect of the varying pressure on the carbon granules in the transmitter is to alternately increase and decrease their resist- ance, thereby alternately diminishing and increasing the strength of the current flowing through them; and if the primary of an induction coil is introduced into the circuit with a transmitter and a battery, the momentary currents induced in the secondary of this coil will alternate in a similar manner according to the law of induced currents'. Thus, the desired alternating current is secured. Moreover, the voltage of these induced currents is very greatly increased. This depends upon the construction of the induction coil itself, the rule being that the voltage of currents in the secondary bears the same relation to the voltage of the primary current as the number of turns in the secondary winding bears to the number in the primary. Thus, if the primary winding consists of 100 turns and the secondary of 2,500, the voltage of the secondary currents will be 25 times that of the primary. Since, as has already been explained, the receiver is sensitive to currents1 of quite minute amperage, a high voltage that will enable the current to overcome line resist- ance rather than a high amperage and low voltage is desirable. The part played by the induction coil in the modern telephone is of immense importance since, as has been stated, its use marks the beginning of practical long- THE MAGNETO TELEPHONE 127 distance transmission. In brief, it accomplishes three things, all important to suc- cessful telephone operation: — (1) It produces true alternating currents in place of the direct current of vary- ing intensity produced by the transmitter and battery alone. (2) It produces currents of much higher voltage (E.M.F.) than it is practicable to secure from voltaic cells operating through carbon transmitters alone. (3) By limiting the circuit over which the current from the battery flows, to the very short one including only the battery itself, the transmitter, and the primary of the induction coil, and by making the last of low resistance, the variations in resistance produced by the varying pressure in the transmitter under the influence of sound vibration are in comparison to the entire resistance quite large. These impulses are impressed upon the secondary current with an increase in strength and amplitude corresponding to the increased pressure of that current, and are success- fully transmitted out on the line to the receiving stations over very great distances. The telephone circuit as produced by including in it an induction coil is shown in Fig. 77. This shows diagrammatically the circuit of the speech-transmitting por- tion of the telephone substantially as it exists to-day. The rest of th^ telephone set is required for signalling and is only incidental to the portion employed in trans- mitting the sounds of the voice. 5 — MAGNETO GENERATOR The generator is simply a small dynamo. It differs from the large dynamos used in generating power and light currents only in having permanent steel mngnets Fig. 78 Magneto generator, five bar in place of the usual electro-magnets. Generators in modern telephones are of various sizes, depending on the kind of service for which they are intended. The largest and most powerful are built with five magnets (five-bar generators) and are the type used in the Forestry Branch standard instruments. They are intended to ring through very high resistances, such as 'are encountered on forest telephone lines, 128 METHODS OF COMMUNICATION FOR FOREST PROTECTION and for the size of the machine are extremely powerful and efficient generators of electric currents. They produce true alternating currents at about 65 to 75 volts and a frequency of 15 cycles per second, are very compactly built, and are not very likely to give trouble. The two principal parts of the generator are the magnets and the armature. The former are horseshoe-shaped and are made of a high quality of steel, and strongly magnetized. Between the poles of the magnets is placed the armature. It consists of an H-shaped laminated iron core around which is wound a coil of fine insulated wire. A small crank with gear wheels is used to rotate the armature at a high rate of speed between the poles of the magnets, thus producing the current. It will be apparent, however, that since the generator serves only to produce current for ring- ing purposes there is no reason why it should be permanently in the circuit. On the other hand, there are certain objections to such permanent connection. The arma- ture winding if permanently bridged across the line would form an additional path to ground, thus reducing the current available for ringing other instruments. Also, injury from outside currents might occur which can be avoided if the armature is disconnected while it is at rest. For these reasons the magneto generators are usually arranged with an automatic circuit-breaking device, by which the winding of the armature is thrown out of the circuit whenever it is 'at rest and is thrown into the circuit by the act of turning the generator crank. It will be noted that as soon as the crank on the standard instrument is turned it slips inward a fraction of an inch. This slight movement serves to close the circuit and throw the coil of the generator armature on to the line, thus permitting the current from the. generator to flow out over the line to ring the bells at the distant stations. 6 — KlNGER The low-frequency alternating current from the magneto generator operates a polarized bell or ringer (Fig. 79) at each station by means of which the attention of the Fig. 79 Polarized ringer, unbiased type distant station is secured. Code ringing is employed on forest lines exclusively; that is, each station has its own signal or call letter made by a combination of long and TEE MAGNETO TELEPHONE 129 short rings, and, although the bells at all stations on the line ring whenever the genera- tor is turned at any one of them, yet, by employing a code, only that station responds whose code signal is sounded. The polarized bell consists of two coils of fine wire, (see L,Ll Fig. 96) with soft iron cores held between -the poles of a U-shaped per- manent magnet, NIS by being attached to S. This has the effect of prolonging the S pole so that the opposite ends of the coil cores have S polarity. Across one end of this pair of coils is a soft iron armature F pivoted at its centre by the screw E. To its centre is attached a slender rod H ending in a small metal ball between the two bells K,K1. Armature F under the influence of the adjacent magnet acquires S polarity at the centre and N polarity at each end. The armature in this condition is attracted equally to both cores and rests against one or the other as it may happen to stop. The coils, however, are connected in series and wound in opposite directions. If, then, a current passes through them it will tend to increase the strength of one pole, and to decrease the strength of or change the polarity of the other. Thus, if L is strengthened, LI will be weakened and the armature F will be attracted to L, causing the clapper II to strike the bell Kl. However, the current being an alternating one, the changes in the strength of the poles will take place first on one side and then on the other alter- nately as the current moves, first in one direction and then in the other. As already stated this takes place fifteen or more times per second, according to the frequency of the alternations of the current from the generator. The clapper H therefore is caused to vibrate very rapidly, striking the bells at each vibration and causing an almost continuous ringing sound. For bridging service as used on forest lines, ringer coils are wound to a resistance of 1,000, 1,600 or 2,500 ohms. The standard Forestry Branch instruments and exten- sion bells have 2,500-ohm ringers. Such high-resistance ringers are employed on heavily loaded lines for the purpose of preventing the escape of current through the ringer circuit of the numerous instruments attached to the lines. These high-resis- tance coils, which are generally bridged permanently across the line, are wound so as to give a very high magnetic retardation, and, although readily operated by the low-frequency currents from magneto generators they are effectual blockades against the high-frequency current of the talking circuit. The higher resistance also is a con- siderable aid in signalling, since it operates to reduce the amount of current that is diverted to the ground at each instrument and therefore increases the number of instruments that may be rung on a given line. It must be noted in this connection, however, that all ringers on the same line must be wound to the same resistance, as otherwise the low-resistance ringers will tend to prevent the others from receiving the proper amount of current. In some instruments the ringer is thrown out of the circuit while the telephone is being used for talking. This is not the case, however, in the standard Forestry Branch instruments. But, although the ringers in these instruments remain perman- ently bridged across the line at all times, their high resistance effectually bars out the talking current, so that this current passes through the receiver to the ground in the instruments in use and not through the other path offered through the ringer coils. It will also 'be noted in the diagram of the wiring of the standard telephone (Fig. 97) that when the generator of any station is being used to ring another station, two paths are available to the current, one through the line wire to the distant station, thence to the ground, and back to the generator whence it came; the other through the ringer of the calling station itself. By this means a portion of the ringing current is shunted through its own bell and this bell is rung the same as are all other bells on the line. The advantage of this arises from the fact that the ringer is particularly liable to trouble due to several causes. It may, for instance, fail to ring owing to improperly adjusted bells or armature, or to coils being burned out by lightning, or to faulty connections in the ringer wiring, or to a short circuit on the line .or in the protector. Such trouble is immediately noted as soon as an attempt is made to ring a distant Nation when the bells are permanently connected across the line: 79211—9 130 METHODS OF COMMUNICATION FOR FOREST PROTECTION 7 — SWITCH-HOOK It has be«ni previously indicated that there are two entirely different sources of electric current in a magneto telephone set. The one is the local battery; the other is the magneto generator. The current from the local battery traverses a very short circuit Fig. 80 Telephone switch-hook through transmitter and primary of the induction coil only, but induces a secondary current in the induction coil which traverses the whole line, thus enabling conversation to be carried on. The current from the magneto generator flows out over the line, also, and actuates the bells at all other stations for signalling purposes. When the instrument is not being used it is obviously undesirable to have the parts used for talking connected to the line. If this continuous connection existed, conversation between any two stations would be heard at all other stations and as part of the talking current would pass through each receiver connected to the line the amount received by any one of them would be proportionately reduced. The leakage through the low resistance of the numerous receivers and induction coils, moreover, would make signalling impossible over long lines with numerous instruments. Furthermore, the continuous current that would flow through the transmitter circuit would quickly exhaust a battery of the open-circuit type such as is used in the telephone. Accord- ingly, in all telephones a device is installed by which the talking circuit is cut off from the line when not in use and the transmitter circuit is opened. This is accomplished by the switch-hook which is so arranged that when the receiver, which ordinarily is suspended from it, is removed, the talking circuit is automatically thrown into the line. Conversely, when the receiver is placed back on the hook, the depressing of this hook opens the circuit. A large number of devices for accomplishing this have been invented. The one shown in Fig. 80 is the type employed in the Forestry Branch standard instruments in wall sets and desk sets. In hand sets such as the 1375-A or the 1004-A portable instruments, push-button devices are. used to accomplish the same result. It is well, perhaps, to note that in case one of these push-buttons is depressed for any long period, the small battery of the portable instrument is very likely to become exhausted. This sometimes happens with the 1375-A hand set where the push-button projects proi linently from the side of the hand set and when packed for TflE MAGXETO TELEPHONE 131 transportation with the receiver cord wound around it, it sometimes is depressed for a long time. Most of the trouble with exhausted batteries in this set is probably due to failure to guard against this accident. 8 — ACCESSORY EQUIPMENT In addition to the essential parts of the telephone previously described there are several pieces of apparatus generally used on forest lines about which it is desirable that some information be available to those in charge of such lines. These include the following : — . (a) Condenser (b) Howler (c) Lightning-arrester or -protector (d) Switches (e) Repeating coils (a) Condensers. — If two conductors, preferably in the form of thin plates such as layers of tin-foil, are placed close together with a non-conducting material or dielectric between them so that they are nowhere in direct contact and are then connected, one to each pole of a voltaic cell, it will be found that a certain amount of current will ROLLED CONDENSER Me. 21- CAPACITY 3L W. F. Fig. 81 Rolled condenser flow from the cell to the plates until they become fully charged with static electricity. Such a device is called a condenser. The ability of an arrangement of this sort to receive an electric charge, generally termed its capacity, varies in direct proportion to the area of the plates, inversely as the square of the distance between the plates, and directly as the specific inductive capacity of the dielectric. It is not essential that the conductors be in the form of plates, however. Any two surfaces, such, for instance, as the surfaces of two telephone wires placed parallel to each other and insulated from each other as on a metallic pole line, will act in the same manner. So also will a single wire line, the earth's surface forming one plate, the wire the other, and the air between them acting as the dielectric. A great many of the difficulties encountered in securing good telephonic transmission are caused by this electro- static capacity of the line. This, however, is aside from the subject of condensers as exemplified in the accessory equipment of the telephone. It was previously stated that if the talking circuits of the various instruments on a line were left in the circuit continuously instead of being cut out by the switch- hook when the receiver is hung up, it would be impossible to ring up the stations on the line, owing to the leakage of the calling current through the receiver circuit. The same thing takes place when on party lines a number of receivers are taken off the iooks by persons " listening in." Signals could not be transmitted over such lines 79211— 9 132 METHODS OF COMMUNICATION FOR FOREST PROTECTION when several persons are " listening in," were it not for the use of a condenser in the receiver circuit. All standard Forestry Branch instruments are thus equipped, the wiring being as shown in Figs. 41 and 97. The condensers used for this purpose consist of alternate strips of tin-foil separated from each other by waxed paper. They have a capacity of half a microfarad. A condenser acts as a complete bar to the passage of direct currents, or, in other words, it constitutes an open circuit. To alternating currents, however, it offers a more or less perfect path depending on the character of the current, particularly its frequency and the capacity of the condenser. The condensers used in the standard instruments readily permit the passage of the high-frequency currents of the talking circuit but bar out the low-frequency currents of the calling circuit almost completely. It is thus made possible to ring through, even though a considerable number of receivers may be off the hooks. Fig. 82 Howler Similarly, a condenser is used with the howler where vibratory currents are employed in signalling as with the 1004-A hand set. These vibratory currents are alternating currents of very high frequency which readily pass through the 1-micro- farad condenser, wired in series with the howler. This condenser, however, effectively prevents the escape to the ground of the low-frequency alternating currents of the magneto generators, so that both types of signalling devices may be used on the one line without short circuiting or interference. (fr) Howler. — For the purpose of reducing the weight of the portable instruments as much as possible it was necessary to do away with the heavy magneto generator. THE MAGNETO TELEPHONE 133 This was accomplished in the 100-i-A hand set by using for signalling an induced current of high potential and high frequency acting upon a special typs of telephone receiver at the distant station. The wonderful sensitiveness of the receiver to small currents of this kind has previously been explained. By this system, therefore, it is possible to work over very faulty lines where the ordinary generator currents are entirely lost through leakage or high resistance. The howler is the special form of receiver used to receive vibratory signals. It is the same aa the ordinary receiver already described except that the pole pieces of the long, horseshoe magnet are "attached to it at right angles. This is mounted in a wooden block for convenient attachment to the wall and is prov:dei with a small megaphone which serves to con- centrate the sound waves given off by the vibrating diaphragm. Howlers are con- nected between the telephone »and the protector so that they are protected from injury by lightning or other high-tension currents andv are not likely to get out of order. They must be carefully adjusted so as to produce the maximum sound, the adjust- ment being accomplished by tightening or loosening the screw-cap which holds the diaphragm in place. The type of howler used by the Forestry Branch is shown in Fig. 82. (c) LigJi-tning-arrester. — It is always necessary to protect telephone instruments against lightning. This is particularly true on many long-d'istance forest lines which cross through regions of high altitude where lightning is sometimes very prevalent. It is also necessary to provide special protection wherever telephone lines are liable Fig. 83 Lightning protector for use where there are no power or light wires to come iii contact with wires bearing electric-light or power currents. Two types of protective devices are employed. In the lightning-arrester used by the Forestry Branch advantage is taken of the fact that a high-tension current such as lightning will jump a small air gap in seeking the shortest path to the ground rather than pass 134 METHODS OF COMMUNICATION FOR FOREST PROTECTION through the long coils of the telephone ringer or other parts of the set. This arrester (Fig. 83) consists of a suitable insulating block A on which 'are placed two pairs of copper blocks B, B1 held together by springs but not in direct contact with each other because of a thin sheet of mica placed between them. A brass bar extends from binding-posts 0 and C1 to the copper blocks nearest them. A similar bar extends from the inner blocks to binding-post D. The line wire is connected to post C and the ground wire to post D. To all ordinary telephone currents the air gap between the copper blocks is an effectual bar. Dust collecting between the blocks caus2S a short circuit but is largely prevented from accumulating by the brass covering cap E. By Fig. 84 Protector with fuses, for use where there are power and light wires. Note method ' of binding edge of asbestos mat with metal tape a lightning current, however, the path to the ground across the air gap is taken in preference to that through the instrument, and in this way such currents are success- fully prevented from damaging the telephones. The effect of lightning-arresters on high-tension currents other than lightning is somewhat similar, but these currents are very likely to be continuous instead of merely momentary as are lightning currents. A " cross " with such a current would therefore result in a constant sparking across the air gap of the protector, which would almost certainly cause a fire if it did no other serious damage. To prevent THE MAGNETO TELEPHONE 135 this a line fuse must be introduced1 in the line between the protector and the outside wires. This fuse contains a short length of easily fusible metal which melts when- ever a current of greater strength than the fuse is designed to carry comes over the wire. The circuit is thus opened and damage by sparking is prevented, as the air g»ap through the fuse is entirely too large for any ordinary high-tension current to jump. Fig. 84 shows a protector designed to guard against both lightning, and power and light currents which has bean adopted by the Forestry Branch for use wherever both kinds of dangerous currents are encountered. This means that on many reserves all instruments must have the combined light- ning and high-power protector, because no matter on what part of the circuit a power line is encountered it is necessary that all instruments oil that circuit be fully protected. Fig. 85 Baby knife-switches. (A) Single pole, single throw (S.P.S.T.). (B) Double pole, double throw (D.P.D.T.) (J) Switches. — For convenience in separating a branch line from a main line, for cutting off stations not in use, for dividing extra long lines into shorter sections, and for other similar purposes, it is frequently necessary to install switches in telephone circuits. As the currents carried are all comparatively weak, no very elaborate switching devices are needed, and a simple, inexpensive form of knife-switch is found to serve all purposes adequately. Those mounted on ade by a suitable p>le-switch, properly mounted, as shown in Fig. 40. A Fahnestock test-clamp may also be used for this purpose as in Fig. 38. 4 — STUB KEIXFORCEMENT FOR POLES Poles that have become seriously weakened? by butt-rot near the ground-line should be replaced, excopt where condilions are such as to warrant reinforcing them 144 METHODS OF OOMMUNIOATION FOR FOREST PROTECTION tu stuff enafs ive// sp/iced white /nsu/crto/ So/derec/ Staples Ptece of board with ley el -- surface, nai/ed to its support To testing instrument" S/o. /4 B XS Rubber- covered, braided, Heather-proofec/, ftr//sfed pair, copper tv/re Bryant k switch tfitkjf'X* blue wood screws. A/ofe:~ Test stations shou/d not be instated w/?ere they ore not necessary. THEE Fig. 93 Method of installing test-station on a tree *by means of a stub of long-lived or treated timber. A stub should ordinarily be used 'where suitable pole timber is not available and to reinforce poles that are sound above the ground, irrespective of their condition at the ground-line. The stub or post should be peeled and' shaved and roofed, as shown in Fig. 94. The sides of the post and of the pole which come in contact should he faced above ;the ground-line to a width of 2 to 4 in., so as to give a greater bearing surface. The diameter of the stub at the ground-line should be at least as great as would 'be required for a new pole. The weaker the pole to be reinforced the stouter should 'be the stub. The stub should ordinarily foe set to a depth of 4 ft. and should extend out of the ground about 5 ft., making the total length from 9 to 10 ft. Strain on the weakened pole should cause it to bear against the stub. For this reason stubs in general should be set in line with the line wire. Where there are pre- MAINTENANCE 145 vailing strong winds from one direction, however, it should 'be set on the side oppo- site. On curves and at corners a stub should be set on each side of the pole in line with the line wire. Where any special strain exists, the largest post available should be used. Wrappings consisting of No. 12 iron wire should be placed as indicated in Fig. 94. Each wrapping, consisting of eight turns around both pole and stub, should be made as tight as possible with pliers or other devices and the ends twisted together with not less than six turns and then 'Stapled to the pole. The wires may be twisted very tight if >an iron rod about i-in. in diameter or one arm of a pair of cutting pliers is inserted! between an equal number of turns at a point opposite the line of contact. Both sets should be twisted at the same time. Where it is impossible to secure sufficient strength by wrapping the stub and the pole together by wire, through bolts should be used. The nuts, washers, and bolts should be of galvanized iron, and the washers about 2J in. square. No back filling should be done until after the stub is in place. The same method should be followed as described! under the heading " Setting poles," in Section 55. 5 — REPLACEMENTS WITH TREATED STUBS In some of the older Forestry Branch lines many poles were used which through improper preparation or use of non-durable species have decayed very rapidly and must be replaced. In making such replacements where the use of more durable poles is specified by the district inspector, some cases will arise wherein treated stubs can be employed! to great advantage. It will be apparent that the treatment and trans- portation of stubs is a much less expensive operation than the handling of full- length poles, and where durable pole timber for making replacements is not available, the use of treated stubs should be carefully considered. Stubs of a durable, species have similar advantages. In making such replacements, however, careful consideration must be given to the condition of the portion of the old pole remaining above ground. Unless this portion of the pole is in first-class condition and gives promise of. lasting as long as the reinforcing stub employed, this method of making pole replacements should not *be adopted. 6 — RESETTING OF SHORTENED POLES The standard specifications for non-durable poles call for a 25-ft. length. Where such poles have decayed and it is desired to replace with durable poles, this object may frequently be attained economically by cutting off the decayed portion of the old poles, treating the sound portion remaining, and resetting the same in the line. This, of course, reduces the height of the lead and cannot be employed1 where such reduction is for any reason undesirable, but in most cases the reduction will still leave a 20-ft. pole and this will often be sufficient. Projects involving the treatment and resetting of shortened poles must always be reported to the district inspector and approved by him before being undertaken. Section 92 — Apparatus 1 — GENERAL REPAIRS All telephone apparatus at stations and elsewhere on the line should be carefully inspected for loose connections or other defects. The inspector should call up the terminal or intermediate stations from each instrument and note particularly how the generator of the instrument rings its own bell and how the bell rings at the station called. The called station should ring back in order to test the bell at the calling station. In making tests it should not be taken for granted that something is wrong if an 79211— 10 146 METHO'DS OF COMMUNICATION FOR FOREST PROTECTION answer is not immediately obtained. If unable to get the station after several attempts, call another station and. try to get a test with it. While the standard instruments and apparatus of the Forestry Branch are among the best made, and liability to trouble with their mechanism has been reduced to a minimum, nevertheless the conditions of use of forest lines are such that certain defects will develop from time to time and frequent, careful inspections are necessary to maintain the equipment at maximum efficiency. Seat/on A A 8 Wraps o~F* /2 Wire Fig. 94 Stub reinforcement of poles The following list of faults taken from the circular of instructions issued by District No. 5 of the United States Forest iService will be of assistance to those who are not experienced in making thorough inspections of telephone apparatus: — All parts of receiver should be intact. Receiver cord should be intact. All nuts on receiver should be tight. MAINTENANCE 147 Receiver cap should be fairly tight. Bent, dented, or rusted diaphragm of receiver should be replaced. Dirt on or under diaphragm should be removed. All wiring inside of instrument should be in good condition. Generator should ring the bell clearly with switch open. Generator crank should not bind when turned. When binding comes on gradually some operators do not know the difference. It is caused by grounds or lack of oil. Short circuits may cause either gradual or sudden binding of the generator. Contacts of the switch-hook should be clean. Generator should be fastened in the instrument securely. Contact points of the generator (left side) should make good connection. All screws inside the instrument should be tight. Adjusting nuts on bell 'should be tight. Resistance of all ringer coils should be the same. Nuts on protector should be tight. Protector blocks should 'be free from soot, smoke, or dust. Protector blocks should be metal, not carbon. Protector should be connected as shown in Fig. 45. Protector should be screwed (not nailed) to wall. !Micas should not be cracked or otherwise injured. Nuts on cut-off switch should be tight (if switches are installed). Blades of cut-off switch should make good contact with springs. Instrument should be screwed (not nailed) to wall. Ground rod should be standard. Ground wire should be soldered k> ground rod. Ground rod should be driven into ground within 8 in. of its full length. Line wires and inside wires should be soldered where they connect with each other. Splices in insulated wire should be taped. Entering wires should run through circular loom or porcelain tubes. All wiring outside should be insulated properly from buildings by being attached to knobs or insulators. Insulation should be good on all inside wires. All battery connections should be tight. Transmitter arm should be screwed tightly to box. Transmitter arm should be tight enough to hold it in proper position. All nuts and screws on transmitter should be tight. Metal parts of battery should not touch each other. Are batteries good? Should be three. The following instructions may be of value to officers who have occasion to test instruments and hunt for faults : — (1) Test the batteries with the battery gauge to determine whether or not they are exhausted. (2) Clean all battery connections, post terminals, and ends of all connecting wires that have become corroded. See to it that all battery terminals, nuts, or screws on the binding-posts are thoroughly tightened. (3) Follow up the wires from the battery to the instrument. Repair them where damaged, and staple if they have become loosened. (4) Tighten all loose connections1 in the telephone instrument. (5) See to it that the switch-hooks work freely. Note carefully that a good con- nection between the contact springs of the receiver hook is made when the receiver is off the hook and the lever is up, and that the contact is broken when the receiver 79211— 10£ 148 METHO'DS OF COMMUNICATION FOR FOREST PROTECTION is on the hook and lever is down. The operation of the switch-hook is sometimes subject to slight imperfections on account of improper working of the switch-arm. This is caused by the lifter spring of the switch-arm losing its tension. 5/mp/e Method of Testing ffece/ver Batteries Connect w/re A to one 3/c/e ofco// fo be tested and touch w/re & to ot/ier s/c/e. 'fc/tc/c /^ Sieord ' co// t's O /< Fig. 95 Receiver >.test •^ (6) Inspect the ringer to determine whether or not the tapper and gongs are in proper adjustment. If not, proceed to adjust them as directed in Section 92. Also refer to Fig. 96. (7) Gently tap the transmitter to foe sure the carbon granules are not packed. (8) The Receiver. The efficiency of the speaking service gradually declining is the most common fault in receivers. This is due to the accumulation of filings, dirt, and rust on the pole pieces which restricts the vibration of the diaphragm. To remedy this difficulty remove the cap, take off the diaphragm with the large end of the receiver down, and gently jar the receiver to remove the filings, etc. The pole piece should be carefully wiped with a clean rag to remove dust, and rust if it is corroded. (9) Speaking service is also often restricted on account of the diaphragm touch- ing the pole piece. This is generally caused by the magnet shifting, or by the diaphragm having become weakened by the continual pull of the magnet against it. Buckled or bent diaphragms are frequently found. This trouble is generally caused by inquisitive or careless persons tampering with the diaphragm. When this fault MAINTENANCE 149 is found, temporary relief may be provided by inverting the diaphragm when it is replaced. A new one should always be provided as soon as possible. (10) The receiver casings are sometimes damaged by expansion and contraction due to changes1 of temperature. This sometimes causes receiver trouble, which can be remedied only by supplying new casings. (11) Inspecting the receiver cord. If the ends are frayed a short circuit often results. If the receiver cord is suspected of being broken it should be removed and tested. It is often very difficult to detect a break in the receiver cord, since it appears intact at one movement, while at the next its continuity is broken. If such difficulty is suspected a new one should be provided. (12) Receiver coils are occasionally fused or burned by electrical currents dur- ing lightning storms. When this happens new receivers must be provided. (13) The wires of a telephone instrument frequently become damaged, and break. When this1 occurs it is sometimes possible to detect the trouble only by testing with a buzzer or by the " receiver test." If the wires are intact the buzzer will hum when the wires of the buzzer apparatus are attached to the respective ends of the suspected wire. If the receiver test is applied a click will be heard when the end of the wires leading from the receiver apparatus are applied to the respective ends of the suspected wire. (14) Induction coils. Fortunately, faults in induction coils seldom occur. They are, however, not immune from damage and sometimes are burned by electrical cur- rents during lightning storms, or if the line wire leading to the instrument comes in contact with transmission lines carrying high-voltage currents. When damaged, a new one must be supplied. A word of caution, however, must be spoken in regard to the tampering with telephone apparatus of those who are entirely inexperienced and ignorant of the mechanism of the equipment. Hasty action may cause much more serious difficulty than that which it is undertaken to correct. Repairs should be undertaken cautiously. If the apparatus does not work well do not meddle with it until you have located the seat of the trouble and know just what to do to correct it. If the fault cannot be found, the instrument should be removed and placed in the hands of an expert for repairs. In most cases it is advisable to send the instrument to the nearest office of the manufacturer. To enable this to be done without interruption of the service, one or two extra instruments should be kept on every forest reserve and installed temporarily in the place of any that are undergoing repairs. 2 — BATTERIES All dry batteries on the line should be replaced at least every twelve months, and more often if necessary. As far as practicable, all the batteries on a line should be renewed at the same time, preferably at the beginning of the fire season. A fresh battery should not be connected to an old one. The inspector should note whether or not battery connections have become loosened. In putting dry batteries back into a telephone, the inspector should see that the zinc binding-post on one cell does not touch the zinc binding-post on an adjacent cell (Fig. 43). An emergency test to determine whether or not a dry cell is absolutely dfead may be made by moistening the finger and gripping the zinc binding-pest, and then touch- ing the tip of the tongue to the carbon binding-post. If a very slight acidulous taste is noted the cell is not absolutely exhausted, although it may be sufficiently so to be incapable of giving good transmission. In extreme emergencies exhausted dry cells can sometimes be temporarily revived to give, sufficient current for sending an important message over the line 'by driving holes with a nail through the zinc shell and allowing water to soak in through them. 150 METHO'DS OF COMMUNICATION FOR FOREST PROTECTION Lightning-protectors should be inspected, and cleaned if necessary, after all electri- cal storms. No. 60-E protector is cleaned by unscrewing the brass cap from the por- celain base, removing the metal protector blocks, >and removing from them any soot or smoke or pits which cause the blocks to touch each other. Both conditions are the result of lightning jumping across the air gap provided by the mica sheet. In locali- ties where lightning is particularly bad and the stations are difficult of access two micas may be inserted between the blocks, thu§ increasing the width of the air gap. 3 — OILING GENERATOR Once every two or three years one drop of typewriter oil or "3 in 1" should be placed in each of the places provided with oil cups. Great care should be taken to see that no oil falls on any of the contacts or rubber bushings of the generator. 4 — ADJUSTMENT OF RINGERS (The following is from Telephone Circular, April, 1916, United States Forest Service, District No. 5.) Ringers not in proper adjustment cause unsatisfactory signalling service. Not infrequently an extension bell or ringer in a telephone is condemned as worthless, when in fact it is merely in poor adjustment. When in proper adjustment either gong, upon one-eighth turn of the generator crank, will transmit a high, clear tone of the same sound. All bells connected to the same line should be of the same ringer resistance. One ringer of different resistance on a line will seriously interfere with signalling. Resistance of each ringer coil is usually marked 800, 1000, 1250, etc. A ringer having two coils marked 1000 each has a resistance of 2000 ohms; two coils marked 1250 each indicate a resistance of 2500 ohms1. The ringers of -a new instrument are often thrown out of adjustment in transit. When the telephone is installed the ringer should be tested and adjusted if necessary. (a) Adjustments. — (1) If the ringer is loose on its base, remove the gongs and tighten the screw which secures the ringer mounting. Replace the gongs and securely tighten the gong screws. (2) Before commencing the adjustment, the instrument should occupy the posi- tion in which it will be operated. If it is connected to a line, disconnect it. (3) If a coil spring should be found attached to the ringer, remove and discard it. (4) The base of the clapper rod (the armature) should have very little vertical play. It should not be tight but should not wobble. It should be adjusted to move freely on the pivots. In making this operation pay no attention to the sicfe movement of the armature. To adjust, loosen the lock nut D (Fig. 96), then manipulate the screw E until the proper adjustment is accomplished. Tighten or loosen to provide just sufficient play in the armature pivots to be visible. With the screw-driver hold the screw in place, and with a pair of long-nosed pliers tighten the lock nut. Care should be taken that the threads are not stripped in this operation and that the screw does not turn. Only a slight pressure should be applied to the lock nut. The gongs should next be so set that the clapper ball strikes but does not rest against them when thrown from side to side. The space between the clapper ball and one gong should be about %6 in. when the clapper ball is held against the other gong. To change the positions of the gongs loosen the clamping screws B only enough to allow the gongs to be moved by the turning of the eccentric adjusting screws C until the correct position of the gongs is obtained. Let the clamping screws remain loose until the stroke of the clapper is adjusted. To make this adjust- ment turn the screw A to the right to shorten the stroke, and to the left to lengthen it. Turn the generator handle only enough to cause the clapper to move toward one MAINTENANCE 151 gong but not to strike back to the other gong at each movement of the handle. The clapper ball should strike the gongs and rebound just enough to clear the gong. It should lie as close as possible without touching the gong. Sometimes the clapper ball tends to rest heavily to one side. If possible" the difficulty should be overcome by moving the gongs or by changing the length of the stroke of the clapper. If the attempt is not successful, bend the clapper rod until the required space is obtained. Then move the gongs to their proper relative positions. Fig. 96 Ringer of No. 127-F, extension bell, and Nos. 1317-P, 1317-S, 300-N and 1336-J telephones (Z>) Testing. — When the gongs and clapper ball appear to rest in their propor posi- tions, test the adjustment by turning the handle of the generator - until the clapper ball strikes one gong without striking back to the other. If the tones are not satis- factory, continue the adjustment until a clear ring of the same tone is emitted by each gong, and at the same time the stated spaces between clapper ball and gongs must be maintained. The clamping screws B should be tightened when the adjustment is complete. Adjustment of ringers in extension bells differs only in method of testing. The test is made by slowly and slightly tipping the ringer from side to side. It should not be jarred. The 292-U loud-ringing extension bell can be more successfully adjusted when it is connected to a line. This allows the adjustment to be tested by signalling to it from some distant telephone. The bell should be installed in a true vertical position; with the clapper pointed either upward or downward. The coil to which the clapper is fastened should move freely between the upper and lower pivot screws, but not loosely. This adjustment is made by manipulating the screws on either side of the armature. The space between the clapper ball and gong should be about £ in. when the clapper ball is held against the other gong. The gongs are adjusted by loosening one at a time the square-headed screws on the face of the gong, turnrng the gongs to the proper position and then tightening this screw 152 METHODS OF COMMUNICATION FOR FOREST PROTECTION before each test. The distance between the clapper ball and the gong after rebound of the clapper ball should be approximately KG in. If in proper adjustment, each gong when struck by the clapper should emit a clear, ringing sound. 5 — PORTABLE TELEPHONES The two standard portable instruments, the 1375-A and the 1004- A, are so con- structed that they are very unlikely to give trouble unless tampered with. Owing to the small size of the battery employed in both these telephones it is necessary to make more frequent renewals than in the permanent sets. No adjustments are required in the 1375-A set, but in order to get the best results from the buzzer of the 1004-A set it is sometimes necessary to alter the .spark gap. This should not be attempted in the field, and any instruments not working satisfactorily should be returned to the district inspector for repairs. The 1004- A hand set and the hand set of the 1375- A 'instrument being of rather thin sheet aluminium are very liable to serious injury through denting. Such dents may cause short circuits which interfere with the successful use of the instruments. When these occur they may often be removed by pressing out from the inside, using a smooth piece of hardwood with a rounded surface. Section 93— " Trouble " 1 — BROKEN CONNECTIONS AND OPEN COILS In the instruments that the Forestry Branch has adopted as standard the chances for trouble have been reduced to a minimum. Lightning is the greatest source of trouble. The riniger coils, which are constructed of fine insulated wire wrapped around an iron core, occasionally burn out. When this happens it is necessary to substitute a new coil. The armature in the generator may also burn out, necessitating replace- ment. (The armature is the part in the generator that revolves between the per- manent magnets. This is composed of two windings around an iron base on opposite sides' of the centre. The generators used on some sets are protected to a certain extent by means of a " shunt.") In the receiver the small coil of insulated wire wrapped around the end of the permanent magnet is sometimes burned out by lightning or heavy outside currents. The induction coil is sometimes similarly damaged. The following methods of testing may be used to locate trouble as just described : Connect one side of a receiver to one pole of the battery. If when the other side of the receiver is touched to the other pole of the battery no click is heard, the receiver is open. By the use of a receiver, if in serviceable condition and the batteries as shown in Fig. 95, any of the wire coils may be tested. A test of the generator may be made by disconnecting the instrument and placing the moistened tips of two fingers over the two screw binding-posts on the end of the generator. If the latter is in adjustment, current will be felt when the crank is turned. If no current is felt probably the armature of the generator is open, and a new armature must be obtained. The hard-rubber bushings sometimes carbonize, due to oil or grease getting on them, and cause generator trouble. It is impossible to talk through the transmitter when the induction coil is open, when the batteries are weak, or when there is a loose connection somewhere in the instrument, as at one of the connections on the batteries or at the switch-hook. 2 — DETECTION AND KEMEDY Trouble in any place is likely to affect the entire system. Inexperienced persons should not be allowed to tamper with telephone instruments. It is usually well to MAINTENANCE 153 have a spare telephone on each reserve, which can be temporarily installed while a telephone or the part of it that is out of order is sent to some reliable telephone man for inspection, repair or readjustment. In general, telephone trouble may be in connection with (1) signalling or (2) talking and hearing. The generator furnishes current for signalling or ringing the Fig. 97 Wiring of No. 1317 telephone set bells, sending a current over the line to all bells on its way to the ground. The generated current is intermittent, and jumps to the ground or is greatly weakened by groundings instead of flowing along the line. The batteries furnish current for conversation only. It is possible to talk over a wire even when there are slight grounds through trees or through the line wire touching the ground in dry places, .but it is not possible to signal. 3 — GUIDE TO CLEARING TROUBLE Trouble No. I, Bell— Cannot ring up anyone; generator handle turns hard; local bell does not ring when generator is turned. Cause. — Protector burned out or dirty. Line wire grounded or wires crossed (ii metallic) ; improper wiring in set or bushings on generator carbonized. 154 METHODS OF COMMUNICATION FOR FOREST PROTECTION Remedy. — Wihen testing to discover the cause of this trouble the receiver should be left on the switch-hook. First disconnect the two wires which enter the telephone set from the terminals marked " Line 1 " and " Line 2," (see Fig. 97) and screw down the connections on the wires coming from the ringer. Now turn the generator. If it turns easily 'and the bell rings well, the trouble is not in the telephone set. Then connect the line wires to " Line 1 " and " Line 2 " terminals and disconnect the line wires from the protector, leaving the inside wires to the telephone set attached to the protector. Now turn the generator handle. If it is difficult to turn, remove the protector blocks from the protector and try the generator again. If it turns easily, clean the protector blocks, replace the thrn piece of mica between them, • and1 put back into the protector. Now test the generator again, ) Fixed flash. The first type is represented by the British Army heliograph. The second type is^ represented by the United States Army and the United States Forest Service heliographs. Section 99 — Use in Forest Protection Although the heliograph has been used by the army for the purposes of com- munication for a great many years, its use in forest protection is a recent develop- ment. So far as is known, this instrument was first employed in forest protection for communication between lookout stations under the direction of the author on the Kaniksu National Forest in Idaho in 1909. This successful demonstration of its utility has been followed by a slow but widespread adoption of the instrument for certain restricted uses on a large number of the National Forests of the United States, and at least one instance of its use in Eastern Canada has been noted. The recent invention by Supervisor D. P. Godwin, of the United States Forest Service, of an improved form of heliograph for forest protection purposes, promises to enlarge greatly the sphere of usefulness of this instrument. While realizing fully the limitations of the heliograph, especially for use in the East or in a flat country, the author believes that its capabilities for enabling the members of a specialized forest-protection staff to maintain intercommunication are very far from being fully utilized or even appreciated. Heliograph stations as employed in forest protection are of three classes : perman- ent, semi-permanent, and temporary. Permanent stations include mountain lookout stations or other fixed points in the forest improvement system where signals may be sent or received with a high degree of dependability during all or part of the fire season. Lookout stations are, from their location and use, heliograph stations of the very first importance, since they not only have a wide range of country constantly under observation but may themselves be picked up with little difficulty from most of the area within their range. Semi-permanent stations are those established at or near temporary camps such as fire, survey, or construction camps or near ranger stations that are not connected to the telephone system. Stations of this class will likely be occupied for signalling 160 THE HELIOGRAPH 161 purposes during only a limited portion of the day. "While their dependability for sending purposes may be high, they are not adapted for receiving messages except during the periods when they are actually occupied. Such periods may be regular or not, according to the facilities and organization in each case. Temporary stations are those established by moving patrol or other moving units of the forest force merely for the purpose of communicating with some other station in the forest. As a rule they will be used for sending messages only and will have little or no value as receiving stations, since they will seldom be occupied regularly but will generally be established only as the moving unit finds it necessary to com- municate with headquarters or some other station. It is obvious that in the first two cases the element of easy portability is of much less importance than in the third. At the most, a heliograph outfit, even of the largest size, is quite easily carried by one man, so that where it is simply a question of setting up an instrument in a suitable location at a permanent or semi-permanent station, any of the usual types may be employed. No special heliograph equipment is there- fore needed for lookout or headquarters use but, as rigidity is an element of some importance and as range is governed by the size of the mirror, one of the heavier models should be selected and the size determined by the ranges over which it is desired to work. When,however, the heliograph is to form a part of the outfit carried by a foot or horse patrolman the question of size and weight becomes extremely important. Such patrolmen are usually loaded to their carrying capacity with tools and supplies requisite for their work, and every item of their equipment must be reduced to the lowest practicable weight. The ordinary military heliographs even of the smaller sizes are too heavy and too bulky to be made a part of the outfit of either a foot patrol- man or horse patrolman, though they might be used by canoe patrol where few portages are necessary, and may be easily carried on any wheeled vehicle used in forest protec- tion except a motor-cycle. This difficulty would seem to be successfully overcome by the new Godwin heliograph described herein. In general the heliograph will find useful application to forest protection inter- communication in the following ways: — (1) Before the construction of the telephone system, to furnish communication facilities to all parts of the forest. (2) As a substitute for an emergency telephone line, operating from temporary camps to lookout or other permanent stations on the main telephone system. (3) As an emergency equipment at all permanent lookout stations to ensure against isolation of the station in the case of a break in the telephone line. (4) As a cheap substitute for a telephone on secondary lookout points occupied during a limited portion of the fire season or during an unusually dry season only. (5) As a cheap substitute for a telephone on lookout peaks which it has not yet been decided are entirely suited for permanent occupation. Section 100 — Range and Speed The range over which the heliograph can be operated depends on the size and per- fection of the mirror, the brightness of the sun, the clearness of the atmosphere, and, to a much smaller degree, upon the angle at which the light is reflected from the mirror and the background against which the signals are seen. While the normal working range of the 4|-in. square or 5-in. round mirror heliograph is about 40 miles, either may be read by the naked eye under ordinary conditions at 50 miles without difficulty, and up to 90 miles with a glass. In the clear atmosphere of the West, ranges of 100 miles have been accomplished. For longer ranges a larger mirror is required. With an 8-in. square mirror signalling has been carried on in Arizona between stations 186 miles apart. Practically, signals may be exchanged between any two points which are inter- visible, regardless of their distance apart. Intervisibility will depend on their distance 79211—11 162 METHODS OF COMMUNICATION FOR FOREST PROTECTION apart, their height, and the height of the intervening ground. The curvature of the earth is the important controlling factor, although signals may be exchanged between points when the right line joining them passes through the intervening ground. On account of refraction of the beam of light its trajectory is an upward curve that passes above the right line joining the two points. (For a discussion of the mathematical de- termination of the intervisibility of any two points, see "Manual of Visual Signal- ling," United States Signal Corps, pp. 83-88.) In actual practice, however, it is .seldom necessary to operate over ranges of greater than 30 to 40 miles and at these distances any of the types of heliograph em- ployed can be depended upon to give satisfactory service. Speed is entirely dependent upon the skill of the operators. It is comparatively easy to attain the ability to send and receive at a slow rate but speed comes only with training and practice. Twelve words per minute may be .sent by skilled operators. In forest-protection work, four to six words per minute may generally be depended upon. Section 101 — Types of Heliograph Although all heliographs operate on the same general principles, there are important differences in the manner in which they cause the revelation and obscura- tion of the flash. Among those which operate by the moving flash method the type employed in the British Army is most commonly seen in Canada. Fig. HELIOGRAPH WITH SIGHTING VANE. British Army type of heliograph, one-mirror 1 — BRITISH ARMY TYPE The British Army heliograph consists essentially of a circular mirror mounted on a horizontal axis on which it is free to move. By means of an attached linger key, this mirror may be tipped so as to throw its flash on the distant station when properly adjusted. Between each revelation of the flash, the light is thrown below THE HELIOGRAPH 163 or on the near side of the distant station and is not visible therefrom. This mirror is mounted directly over the head of the tripod on which the instrument is sup- ported when in use, and various parts required for its proper alignment, adjustment, and operation are provided. For use when the sun is behind the operator, a second mirror is employed. The details of this instrument may be seen in Figs. 98 and 99, wherein it is shown as employed with one and with two mirrors. HELIOGRAPH WITH DUPLEX MIRROR Fig. 99 British Army type of heliograph, two List of Parts, Figs. 98 and 99: A, signalling mirror in metal frame; B, U arms for ditto; C, tangent box with lid below ; D, tangent screw head ; E, key ; F, key spring ; G, capstan screw, H, collar ; I, vertical rod in vertical socket ; J, clamping screw for ditto ; K, jointed arm ; L, clamping screw for ditto ; M, gun clip ; N .clamping screw at end of arm ; O, sighting rod ; P, sighting vane and mark ; Q, unsilvered spot ; R, German silver ball attached to claw R' ; S, base plate ; T, key bridge ; U, key bearing ; V, anchoring hook ; W, duplex mirror ; X, U arms for ditto; Y, butterfly or pivoting screw; Z, tripod. This type of instrument has the following advantages : — (1) The sending key is also one of the adjusting screws and the operator can therefore have both hands on the adjusting screws even while sending. (2) Only one tripod1 is required and no screen is necessary. (3) The instrument is manufactured in Canada and more readily procurable than other types. (4) Operators skilled in the use of this type may be secured in Canada. Other types are practically unknown. There are some disadvantages, however, as compared to other ^ types, several of which are particularly objectionable for the uses to which the heliograph is mostly put in forest protection. These will be referred to in considering the advantages of the several other types .available. 2 — AMERICAN ARMY TYPE The heliograph adopted by the United States Army Signal Corps,^ which is the type that has been most extensively employed to date in forest-protection communi- 79211— Hi 164 METHODS OF COMMUNICATION FOR FOREST PROTECTION cation, operates on the fixed-flash system. In this system the revelation and obscura- tion of the flash is accomplished not by the motion of the mirror itself but by means of a separate screen placed between the mirror and the distant station in such a way as to entirely cut off the light when closed but permit it to pass freely when opened. Two tripods are required, one to carry the screen and the other the helio- graph proper. The latter consists of two square plane mirrors, each 4| in. to a side, and a mirror bar on which these are mounted when in use. As the mirrors when Fig. 100 American Army type of heliograph, one-mirror Fig. 101 American Army type of heliograph, two-mirror A, square mirror ; B, mirror yoke ; C, mirror adjusting screw ; D, unsilvered spot ; E, tripod ; F, hook for weight ; G, sighting-rod ; H, sighting-rod vane ; I, mirror bar ; J, screen ; K, screen key ; L, screen spring once set and aligned do not need to be moved except to adjust them to follow the motion of the sun, the auxiliary parts are very simple, consisting merely of two THE HELIOGRAPH 165 tangent screws by which each mirror may be turned on its horizontal and vertical axes. The details of this type are shown in figs. 100 and 101 as used both with one mirror and with two. The screen shown ,'n Fig. 100 is 6& in. square and is operated by a downward push on the key causing the thin vanes of which it is made to align themselves with their edges across the path of the beam of light, thus permitting it to pass through to the distant station. Once the flash is aligned with this type of instrument it remains fixed! and all movements are confined to the screen by which the dots and dashes of the code letters are formed. The advantages of this type of instrument are as follows : — (1) It is very simple in design with few small parts and none that are subject to much wear in operation. (2) The square mirror has a greater area, f22 3 1112 8 2111 4 2221 9 1221 5 . . 1122 0 2112 ABBREVIATIONS A After T The B Before U You C Can Ur Your H Have W Word N Not Wi With K Are Y Yes 79211—12 178 METHODS OF COMMUNICATION FOR FOREST PROTECTION CONVENTIONAL SIGNALS End of word. .3. End of a sentence. .33. End of a message. .333. Acknowledgment, or I understand. .22 22 3. Eepeat last word. . 121 121 33. Repeat last message. .121 121 121 Wait a moment. .1111 3. Signal faster. .2212 3. Cease signalling. .22 22 22 333. 4 — ALPHABETICAL SQUARE CODE This code is constructed according to a very simple rule which may be easily remembered, so that it is possible to improvise the entire code at any time. Aside from this it would not appear to "have any marked advantage over other codes. The code is made by arranging the letters of the alphabet in five vertical columns of five letters each, K being omitted and C substituted for K wherever it occurs. Each letter is then represented by a number of two places, the first figure being the number of the column in which the letter occurs, counting from the left toward the right, and the second its place in this column counting from the top downward. This arrange- ment is as follows : — 1 2 3 4 5 1 a f 1 q v 2 b g m r w 3 c h n s X 4 d i 0 t y 5 e j P u z The alphabet follows: — a=l-l f=2-l ! g=2-2 l-5 i=2-4 j=2-5 1=3-1 n=3-3 o=3-4 p=3-5 q— 4-1 r=4-2 s=4-3 w— 5-2' x=5-3 u=4-5 z=5-5 Each letter is made by sending short flashes only, to the number of each cf the two elements of the letter, with a short pause amounting to one beat of time between these elements. A pause of two "beats of time is allowed between the letters, and between words there is either a pause of three beats or the long flash may be used, as with the 'Myer code. The latter is to be preferred with poorly trained operators. Thus the letter M (3-2) would be represented by three short flashes, a pause of one beat of time, and then two short flashes. Experiment has shown that a message may SIGNALLING WITH THE HELIOGRAPH 179 be sent with this code quite as rapidly as with the Myer code and only a little less rapidly than with the International Morse code. The fact that each letter con- sists of only two symbols, and that only dots are sent and no dashes, makes it an easier code to send intelligibly and to read. The further fact that it is made according to a simple rule as already explained, is an advantage in forest-protection work, where the use of the heliograph is confined to a limited portion of the year and where operators will generally not be able to keep in practice. In the district where this code is employed for forest-protection communication the following numerals and conventional signals have been adopted: — NUMERALS B 1 G C 2 H D '. . 3 I E 4 J F . . 5 M CONVENTIONAL SIGNALS End of word Interval (2 seconds) End of sentence or message. . 1-6 Wait a moment 6-1 I understand 2-6 Signal faster 6-2 Repeat last word 3-6 Cease signalling 6-3 Repeat last message 4-6 I wish to use message code . . 6-4 Section 113— Instructions to Operators In sending with the heliograph it is of the utmost importance that uniformity in mechanical movements of the screen be cultivated, as lack of rhythm in the signals of the sender entails unnecessary and vexatious concentration of attention on the part of the receiver. The first position is to turn a steady flash on the receiving station. The signals are made by long and short flashes. Use y the display of two colours in the proper sequence, and those which form code letters by flashes of one colour only, showing dots and dashes as with the heliograph. The range of the first class is entirely too short to be of any use in forest protection. The second class offers greater possibilities. Flash lanterns for signalling purposes are available, using as the source of light acetylene gas, oil, gasolene, limelight, and both incandescent and electric arc lamps. Two principal types are employed; those which burn continuously and operate with a screen like a fixed-flash heliograph, and those which operate with a key and burn intermittently only. The oil, gasolene, limelight, and arc lamps are of the first type. The acetylene and incandescent lamps are of the second type. 1 — TYPES OF SIGNAL-LANTERNS 'Signal-lanterns of various forms are employed principally for military and naval communication purposes. The ordinary electric searchlight makes an excellent signal- lantern and can be used either behind a screen for the sending of Morse signals, or the beam can be used to send wigwag signals even between stations that are not them- selves intervisible. It is not, however, a practical lamp for forest communication because of the large amount of power required for its operation, not to mention its great weight and lack of portability. Among readily portable signal-lanterns two principle types are available. These are the acetylene lantern, and the electric signal-lantern using dry cells as a source of power. Both have to a limited extent been employed in forest-protection communication. (a)» Acetylene Lamps. — The acetylene signal -lantern is used extensively by the; American Army Signal Corps, and the most read'ily procurable lanterns of this type are those adopted by that Service. Two sizes, the field lantern and the station lantern, are employed. For lookout use the station lantern, which is the larger, is preferable as it is as readily portable as the requirements of this service demand and has by far the longer range. This lantern is built in 4he form of a small searchlight with a 5-in., aplanatic lens mirror and S-in. focus. It is mounted on a 'suitable tripod .and equipped with a special gas-generator, a sighting-tube, and a small reading-lamp, the whole equip- ment weighing about 20 pounds. The generator is hung to the legs of the^tripod beneath the lantern and is charged with 1 pound of calcium carbide and 1 gallon of water. This charge is sufficient for about 5 "hours' -signalling, and recharging requires only a few minutes. The sighting-tube in the form of a small telescope is attached to one side of the lantern. It is provided with cross-hairs and i-s used to direct the beam of light on the distant station. Once the lantern is properly aligned, it requires no furtl. adjustment, in which respect it is much superior to the heliograph. The supplementary reading-lamp is required with all forms of 'signal-Ian terns, as the intermittent flashes of the signals do not afford light enough for reading or recording messages. It is an acetylene lamp also, securing gas from the generator that supplies the signal-lantern. 182 SIGNALLING 183 This form of lantern may be used with a screen similar to the heliograph screen, but to do so the light must burn continuously during signalling. This more than doubles the consumption of carbide, since one charge of the generator will furnish gas for only 2 hours' continuous light. The speed of operation with a screen is eight to fourteen words per minute. Fig. 106 Acetylene signal-lantern with tripod As usually employed, the screen is dispensed with and a special form of key is used which controls the supply of gas to the burners. A small amount of gas is admitted continuously. Depressing the key causes a full flow of gas to be admitted to the burner, giving a bright flash lasting as long as the key is held down. The response to the key is instantaneous. Operated in this manner, less carbide is used but the speed is slightly reduced, being about five to ten words per minute. Smoke, fog, rain, and also bright moonlight are the principal impediments to the use of this lantern. The range under ordinary conditions of operation does not exceed 30 miles when viewed with a telescope, and about half this when observed with the naked eye. (ft) Electric Lamps. — For comparatively short-distance work the electric signal- lamps, such as are used by the British Army, are very convenient. Such a lamp is the Stevens-Lyon lamp, manufactured in London. This lamp weighs 10* pounds 184 METHODS OF COMMUNICATION FOR FOREST PROTECTION complete and may be mounted en a heliograph tripod. It can be easily read without a telescope at 11 miles. The source of power in electric lamps such .as this is the dry cell. In order to reduce battery consumption, all signal-lamps of this character operate with a key or switch, by means of which the circuit is made and broken in such a way as to form the letters of the Morse code. In the Stevens-Lyon lamp this key is placed on the top of the lamp and is shaped like the ordinary Morse key used in telegraphy. A sighting-tube and a small oil reading-lamp are also provided and serve the purpose already described. This is a very compact, easily portable and easily operated lamp, and within the limits of its range might often be preferred to the acetylene lamps. For use with it the inert type of dry cell is made up with the excitant in the form of a dry powder instead of the paste used in the ordinary dry cell. Cells of this type are made ready for use by adding water through a tube placed in the cover for the purpose. They have the great advantage of not deteriorating even when kept stored for long periods. Such cells, however, are not read'ily procurable and as a rule can be obtained on special order only. Fig. 107 Fischer high-power electric signalling lamp (c) Fischer High-power Lamp. — The most promising signal-lamp thus far pro- duced is the Fischer triangulation lamp used by the United States Coast and Geodetic Survey as a night signal on its triangulation stations. This lamp employs an 11-in. reflector and, although not as yet fully perfected as to details, it is believed it can be produced1 to weigh about 24 pounds and to cost under $50, without the dry •cells. Eighteen cells are employed to furnish the current and these will give about 9 hours' continuous service. A-s used intermittently in signalling they will last a considerably longer period, depending on the amount of such use. This lamp has the usual sighting-tube, reading-lamp, and switch-key. Its dis- tinguishing feature is a -specially designed, gas-filled bulb having a highly concen- trated filament which, with a 6-volt, 2at the base; or the supporting pole may be set on a ball-and-socket joint to permit of rotation. For signalling by the semaphore method, only two arms are required and these are fixed on the same pivot near the top of the upright pole. The letters are made by the position of these two arms just as when using flags held in the hands. In addition to the two movable arms it is necessary to have a third shorter fixed arm called the "indicator." This arm is placed on the right of the sender, the left as viewed by the receiver. The code is the same as used with hand flags and is illustrated in Fig. 112. USING THE FLAG 193 To signal with the Morse code four arms and the indicator are required. An arm placed at an angle of 45° to the upright post forms a dot of the code; one placed horizontally or at an angle of 90° forms a dash. The signals are read from the top down. The front or "3" of the Myer or Wigwag code is made by dropping all arms to the vertical position. Although limited in range and, except in the smaller sizes, slow to operate, this apparatus may sometimes be found useful on lookout stations', especially those equipped with towers and read from only one direction. The con- ANNULLING NTERRQGAT .TTENTlON O SIGNALS (FOLLOW) NEGATIVE PREPARATOR ACKNOWLEDGE LETTERS NTERVAL Pig. 112 Two-arm, fixed semaphore code struction is simple and the signals more easily read than the flag at a similar dis- tance. Code messages are readily set on a fixed semaphore and kept displayed for long periods. In fact, this is by far the most useful application of the fixed sema- phore to forest protection, and, as about 650 code messages can be sent using one and two letters only, by building a semaphore with two sets of movable arms on a lookout peak any one of the 650. messages may be set on the semaphore and left dis- played to the view of the entire protection staff within range of the station. The arms should be painted according to the colour of the background against which they are displayed. Yellow or orange with a red strip will generally be found mrst effective. 79211—13 CHAPTER XXIV MESSAGE CODES Section 128 — Purpose of Codes Message codes are devised in order that preconcerted phrases or sentences may be expeditiously transmitted. They are widely employed in various lines of activity •and can be made extremely useful in forest-protection communication, especially where methods of communication other than the telephone are relied upon and the operators have had only limited training. In these codes, one, two, or three letters of the alphabet are used to designate each prearranged sentence, and' by having a well arranged copy of the code at each station it is possible to send and receive whole sentences or messages in the time needed to transmit only these one, two, or three letters. Section 129— Use in Forest Protection A message code is particularly adaptable to forest fire detection work. The first code used in forest protection was- employed by the author, with lookout stations equipped with heliographs, in 1909. Others have since been devised, the latest being that of the United States Forest Service in District 1, issued in May, 1916. To a certain extent it is necessary to devise a code to fit the conditions of operation, and the main problem lies in anticipating the messages that it will be necessary for the operator to send. Thus far, mesisage codes have been employed only for the sending of messages from lookout stations. A code of this sort is given in the " Dominion Forestry Branch Message Code" (see note below). This code will be employed for signal communication on Dominion forest reserves wherever signal equipment is installed. If it is found necessa-ry to alter or extend it to fit local conditions this may readily be done by following the rules for preparation given in the " Dominion Forestry Branch Message Code." / Section 130 — Combinations Available With two letters of the alphabet in each signal and with no repetition of a letter in any display, 624 combinations are possible, and each may represent a prearranged phrase, sentence, or message. By using the single letters of the alphabet and also such combinations as A A, B B, etc. 52 additional signals may be obtained, making 676 in all. From these, however, it will be advisable to eliminate the various letters and combinations usecfr as conventional signals in the International and other codes, but there will still remain well over 650 available combinations. Six hundred and fifty phrases give a range of possibilities that covers rather fully the urgent messages that need to be sent by one lookout man to another, or to headquarters, and the saving in time is apparent when it is considered for instance that by sending simply two code letters the lookout man may be enabled to transmit such a message as : "I have sighted a fire, the azimuth bearing of which from my station is 24 degrees." If 650 signals are not sufficient, by using combinations of three letters in addi- tion to those composed of one and two, more than 16,000 different signals are made available. ]\T0fp — The preceding sections deal with codes in general, their purpose and scope. The particular code prepared for the use of the officers of the Dominion Forpstrii Branch is, for convenience, published in the form of a small, separate book entitled "Dominion Forestry Branch Message Code." 194 CHAPTER XXV DANGER SIGNALS Section 131 — Risk in Fire-fighting Fighting forest fires in heavy timber is a work attended' with considerable hazard. Injuries caused by falling trees are frequent, but loss of life is generally due to crews being cut off by fires of the existence of which in their near vicinity they were unaware; or by the sudden development of dangerous conditions in the fire they are themselves fighting, due to high winds or other causes. Nearly 100 men were thus burned or suffocated in the National Forests of Northern Idaho in 1910. Loss of life among fire-fighters has occurred to a certain extent in nearly every region where an aggressive effort is being made to protect the forests from this enemy. This is, of course, in addition to the loss of lives among settlers and inhabitants of forest communities in regions where forest protection staffs either do not exist or have not the organization and efficiency required to protect the community and confine losses to the active field forces who must necessarily take certain risks. Section 132 — Use of Danger Signals In order to guard fire-line crews as much as possible from the risk attendant upon the sudden development of dangerous conditions several protective organizations have considered it advisable to adopt a simple code of danger signals to be used only in case of great emergency on the fire-line. Such signals must be easily made with equipment that can be available at all times, and must be of such a character that they can be conveyed simultaneously to all the men working on a fire-line of the usual length. To avoid any chance of signals being given improperly or by un- authorized persons, it is preferable to have them made by some instrument not likely to be in the possession of such persons. The signals that best meet these require- ments are revolver shots or whistle blasts. The' distance over which shots may be heard in the woods varies with the wind direction, the size of the cartridge, the inter- vening topography, and the outside noises. In ordinary timber on level ground, with no wind or unusual noises, the report of a -3'S-calibre revolver may be heard at a distance of | to 1 mile. Whistle blasts vary with the kind of whistle employed and also with the wind, topography, and outside noises. The type known as a two-tone police whistle may be heard under the conditions described above at a distance of 200 yards. Signals of this kind are useful, of course, only to the actual fire-fighting forces. Where, as is usually the case, the forest-protection staff also has the duty of providing for the safety of forest communities, the general forest intercommunication system and the discipline of the staff itself must be relied upon to safeguard these interests. Section 133 — Code of Danger Signals The following code of danger signals has been adopted by the forest officers in the National Forests of the State of California and will also be employed by officers of the Dominion Forestry Branch. All men going on the fire-line should be instructed in these signals and the officer in charge of the fire will carry a revolver or automatic pistol or a suitable whistle. - (A series of any number of single shots or short whistle blasts with intervals of not less than two seconds between each)=" The fire is in a dangerous condition.- Escape by running down hill." 79211— 13i 195 196 METHODS OF COMMUNICATION FOR FOREST PROTECTION (A series of any number of double shots or double whistle blasts with intervals of not less than two seconds between each pair)=" The fire is in a dangerous condition. Escape by running up hill" (A series of more than two single shots, generally the gun-fall or discharges as close together as possible.) or — (A series of more than two long whistle blasts with intervals of not less than 4 seconds between each, repeated until a response is received) =" Assemble at this point." Section 134 — Miscellaneous Uses of Shot and Whistle Signals The usefulness of shot and whistle-blast signals is not, however, confined to warnings on fire-lines, although in the vicinity of fires they should be used for no other purpose, in order to avoid any chance of confusion. Both, however, may be used to advantage by survey parties, cruisers, packers, and others. In hunting strayed horses, for instance, it often saves much inconvenience and loss of time if the man who first locates the stock conveys news of the fact to the others engaged in the hunt by shots or whistle blasts. Many other cases are constantly arising in forest work where such signals may be used to very great advantage and with much gain in efficiency. A striking example is in the work of " pulling wire " when building tele- phone lines, and in u pulling slack " on tree lines. A simple code of shot signals should always be arranged by wire-pulling crews so that the man watching the reel can signal the pulling crew to stop, start, or come back, as may be necessary. It is in fact the duty of every leader of a party in the woods to study the con- ditions under which his men are working and to devise a simple code of audible signals by which they may communicate with each other, using as the signal-pro- ducing mechanism the handiest equipment in the outfit. Under most conditions this will be a six-shooter or an automatic pistol. APPENDIX A OUTFIT FOE TELEPHONE CONSTRUCTION CREW The tools and supplies required for the construction of a telephone line will vary somewhat according to whether a tree line or a pole line is to be built. The size of the crew will probably vary also. In the following lists, however, a ten-man crew including foreman, cook, and teamster has been taken as the basis for the calcula- tions. Provision is made for having all the tools that may reasonably be needed on the job. Makeshift substitutes or special trips for tools not provided at the proper time cost much more than the transportation of a few extra tools. 1 — TEN-MAN CREW FOR TELEPHONE CONSTRUCTION Pole Line — . Tree Line — 1 foreman. 1 foreman. 1 cook. 1 cook. 1 teamster or packer. 1 teamster or packer. 4 linemen (some of the linemen will have 3 linemen (some of the linemen may have to assist in digging holes and setting to be employed part of the time in clear- poles part of the time). ing right of way). 2 groundmen. 3 groundmen. 1 utility man. 1 utility man. APPENDIX A— OUTFIT FOR CONSTRUCTION CREW 197 2 — LIST OF LINE SUPPLIES (Material per mile of Standard Grounded Circuit) (a) Pole Line — 30 poles, 22^ or 25 feet. 320 pounds No. 9 B.W.G., B.B. galvanized- iron telephone wire. 30 12-inch painted oak brackets. 30 regular pony, long-distance, glass in- sulators. 4-inch and 30 6-inch galvanized wire 30 nails. 30 2-inch fence-staples. Approximate total weight, 7,900 pounds. (b) Tree Line — 315 pounds No. 9 B.W.G., B.B. galvanized- iron telephone wire. 55 standard, porcelain, split tree insulators. 55 4 -inch or 3 -inch iron staples. 5 pounds No. 12 B.W.G., B.B., galvanized- iron telephone wire. Approximate total weight, 350 pounds. NOTE. — Additional materials must be provided for braces, guys, and special construction, if any, according to the conditions in each individual case. 3 — LIST OF STATION SUPPLIES (Material required per Station) (a) Standard Indoor Installation — (For trade description of supplies see List of Standard Equipment, Section 44.) 1 1317-S type telephone set. 3 dry cells. 40 ft. No. 14 B. & S. gauge, rubber-covered. weather-proof, copper wire. 10 ft. No. 19 B. & S. gauge, rubber-covered weather-proof copper wire. 1 standard protector. 2 standard protector micas. 4 standard protector blocks. 1 7-ft. standard, galvanized-iron ground rod. 1 12 -inch oak bracket. 1 standard glass insulator. 6 No. 4£ porcelain knobs. 6 3-inch flat-head wood screws. 2 porcelain tubes. 6 by 1 by i%e inches. 5 IJ-inch blued, round-head screws. 20 i-inch Blake insulated staples. 2 7 -ampere tubular line fuses (required only with 58-F type protector). 1 asbestos protector mat (required only with 58-F type protector). 2 ft. brass oilcloth binding. , 1 howler (required only for receiving vibra- tory signals). 1 condenser (required only for receiving vibratory signals). Approximate total weight, 50 pounds. (5) Standard Outdoor Installation — 1 1336-J type telephone Set. 4 3 -inch galvanized-iron lag screws. 2 wooden cleats, 3 by 4 by 18 inches. 8 6-inch wire nails. 1 protector mounting-box. 1 60-E type protector. 4 standard protector blocks. 2 standard protector micas 1 S.P.S.T. baby knife-switch. 5 2-inch blued, round-head screws. 30 feet No. 14 B. & S. gauge, rubber-covered, braided and weather-proofed, copper wire. 1 7-ft. galvanized-iron ground rod. 30 2 -inch Blake insulated staples. 2 dry cells. Approximate total weight, 115 pounds. 4 — LIST OF CONSTRUCTION TOOLS (a) Pole-line Construction — 7 long-handled, round-pointed shovels. 5 7-ft. digging spoons. 1 standard tree-trimmer. 5 combined digging and tamping bars. 1 standard post-hole auger. 3 double-bitted axes with handles. 1 brush-burning torch (where needed). 4 reversible splicing clamps. 5 8-inch linemen's pliers. 4 pairs eastern climbers with pads and straps. 4 linemen's belts Tvith safety straps. 5 hand-axes, Hudson Bay pattern. 2 Buffalo grips with pulleys. 1 Haven clamp. 1 3-inch double pulley block (with one hook). 1 3 -inch double 'pulley block (with hook and eye.) 35 ft. 1-inch sash cord. 35 ft. 1-inch sash cord. 1 wire-reel. 1 pole support (for poles 35 feet and over, only). 4 pike-poles (for poles 30 feet and over, only). 1 12-inch monkey wrench. (a) Pole-line Construction — Con. 1 carborundum grinder. 2 double-bitted axe-handles. 1 brace and P-inch bit (12-inch twist. 6-inch shank). 3 carborundum whetstones. 4 -inch. 6 10-inch flat files. 1-12-inch wood rasp. Approximate total weight, 380 pounds. (&) Tree-line Construction — (When an occasional pole will have to be set on a tree line, sufficient pole-setting tools to handle the work must be included in the outfit.) 8 double-bitted axes with handles. 1 cross-cut saw (2-man). 2 steel felling wedges. 1 peavy. 1 brush-burning torch. 3 reversible splicing clamps. 4 8-inch linemen's pliers. 3 Eastern climbers with pads and straps. 3 linemen's belts with safety straps. 4 hand-axes, Hudson Bay pattern. 3 standard tree-trimmers. 198 METHODS OF COMMUNICATION FOR FOREST PROTECTION 4 — LIST OF CONSTRUCTION TOOLS. — Continued. (&) Tree-line Construction — Oon. 1 wire-reel. 1 carborundum grinder. 6 carborundum whetstones. 4 -inch. 12 10-inch flat files. 12 8 -inch flat files. 1 saw-filing and saw-setting- outfit. 1 12-inch wood rasp. 4 double-bitted axe-handles. Approximate total weight, 185 pounds. (c) Emergency -line Construction — (The requirements vary according to the type of construction attempted. This list is the maximum for a line hung on trees or bush, and in a pinch most of these tools can be omitted.) 1 pair 6-inch side-cutting pliers. 1 emergency wire-reel. 2 hand-axes. 1 crook-stick. 1 roll friction tape. (c) Emergency-line Conctruction — 'Con. 1 ball cotton twine. 60 3-inch nails. 1 pair climbers. Approximate total weight, 17 pounds. (d) Station Installation — 1 carpenters' hammer. 1 8 -inch screw-driver. 1 4 -inch screw-driver. 1 brace and n/ie-inch bit (12-inch twist. 6- inch shank). 1 gasolene blow-torch. 1 quart gasolene. 1 soldering copper. 1 pound resin-core solder. 1 roll friction tare. 1 pair 5-inch oblique, side-cutting pliers. 1 pair 6-inch long-nosed pliers. 1 monkey-wrench. 1 knife, electricians'. Approximate total weight, 16 pounds. 5 — LIST OF TENTAGE 1 12-by-14-ft. wall tent with fly (cook tent). 1 12-by-14-ft. wall tent with fly (mess tent). 3 7-by-9-ft. wall tents (sleeping tents). Approximate total weight, 350 pounds. 6 — LIST OF PROVISIONS (Ten men for ten days — 100 rations) Flour, 100 pounds. Cured meats, 75 pounds (if fresh meat is available, use 50 pounds cured, 25 pounds fresh). Potatoes, lO'O pounds. Beans, 20 pounds. Sugar, 40 pounds (if syrup is preferred, re- duce sugar accordingly). Lard, in 5-pound pails, 10 pounds (if fresh meat is used increase lard to 15 pounds) Graham flour. 5 pounds. Pancake flour. 6 pounds. Salt, 3 pounds. Baking powder. 3 pounds. Soda, 1 pound. Yeast cake, 1 packet. Butter, creamery, 1-pound cartons, 10 pounds. Dried fruits, 20 pounds. Rice, 5 pounds. Coffee, ground, good grade, 1-pound sealed tins, 10 pounds. Tea, 1 pound. Cocoa, i -pound cans, 2 pounds. Cheese, 5 pounds. Milk, carnation grade, 48 cans. Macaroni, 2 pounds. Corned-beef, 2-pound cans, 5 cans. Tomatoes, 2J-pound cans, solid pack, 8 cans. Peas, 2-pound cans, solid pack, 5 cans. Corn, 1-pound cans, solid pack, 10 cans. Sauerkraut, 3 pounds. Rolled oats, 10 pounds. Cornmeal, 5 pounds. Eggs, 10 dozen. Ketchup, 2 bottles. Pickles, sour, 1 kit (or 2 gallons). Mustard, ground, 4-oz. can. Pepper, ground, 8-oz. can. Cinnamon, ground, 4-oz. can. Allspice, ground, 4-oz. can. Lemon extract. 4-oz. bottle. Vanilla extract, 4-oz. bottle. Vinegar, 1-quart bottle. Soap, laundry. 5 pounds. Matches, 3 small packages. Candles, 2 pounds. Coal oil. 1 gallon. Chloride of lime, |-pound cans, 4 cans. Onions, 10 pounds. Approximate total weight, 550 pounds. 7 — LIST OF KITCHEN EQUIPMENT (Crew of 10 men, including foreman and cook) 1 granite coffee-pot, 8 -quart. 1 granite tea-pot, 3 -quart. 1 lantern. 2 single-bitted axes. 1 sheet-steel cook-stove. No. 8, with 6 joints 2 dishpans, 14-quart. of pipe. 4 frying pans, assorted sizes. 2 granite kettles, 12-quart, with covers. 4 granite kettles, 6-quart with covers. 2 granite stew-kettles, 6-quart, with covers. 1 granite rice-boiler, 6-inch. 2 dripping-pans to fit oven of stove. 1 can opener. 1 rolling pin. 4 tin wash basins. APPENDIX SI— USEFUL BOOKS OF REFERENCE 199 7 — LIST OF KITCHEN EQUIPMENT. — Continued. 4 tin water-pails, 10-quart. 5 yards 12-ounce duck or light canvas, 36- 3 tin dippers, 1-quart. inches wide (this item is intended to be 11 dozen retinned plates. used for tops for table frames built of 1* dozen retinned cups and saucers. light poles. Narrow strips of wood, like \ dozen retinned dish-up basins. 2-quart. lath, 36-inches long, should be tacked to i dozen retinned dish-up basins, 1-quart. the canvas 1-inch apart. The cover thus 1 dozen porridge bowls. made can be kept clean quite easily and 1 retinned syrup pitcher, 1-quart. may be rolled up into a compact bundle 1 retinned cream pitcher, 1-quart. and readily packed from one camp to an- 2 butcher knives, one 10-inch, one 12-inch. other. Two covers are provided — for 1 butchers' steel. mess table 9 feet long and for cook's 1 meat fork. table 6 feet long). 2 retinned stirring spoons. ^ pound 10 -ounce tacks. 1 meat saw. 10 pounds assorted nails. 4 tin milk pans, 5-quart. 1 carpenters' hammer. \\ dozen wood-handled, steel knives and 1 carpenters' hand-saw. forks. 1 alarm clock. 1'J dozen tea-spoons. 10 yards unbleached muslin. li doz?n table-spoons. 10 yards crash towelling. 1 5-gallon can, galvanized iron. Approximate total weight, 325 pounds. NOTE. — The lists of tents, provisions, and kitchen outfit are taken from ''Trail Construction on the National Forests," issued by the United States Forest Service. APPENDIX B USEFUL BOOKS OF REFERENCE 1 — SCIENCE OF TELEPHONY " American Telephone Practice " by Kempster B. Miller, published by McGraw- Hill Book Co., 239 West Thirty-ninth St., New York City, U.S.A.— price, $4. "Practical Telephone and Guide to Telephone Exchange" by T. S. Baldwin, published by Frederick J. Drake & Co., 1328 South Michigan Boulevard, Chicago, 111., U.S.A.— price, $1. *"A.B.C. of the Telephone" by James E. Homans, published by Theo. Audel & Co., 72 Fifth Ave., New York City, U.S.A.— price $1. " Telephone Engineering " by James E. Homans, published by Theo. Audel & Co., 72 Fifth Ave., New York City, U.S.A.— price, $1. " Modern American Telephony " by A. B. Smith, published by Fred J. Drake & Co., Chicago, 111., U.S.A.— price, $2. 2 — LINE CONSTRUCTION *" How to Build Rural Telephone Lines," issued by the Northern Electric Co., Montreal, Quebec — price, 50 cents. " Telephone Construction and Maintenance on the National Forests," issued by the United States Forest Service, sold by the Superintendent of Documents, Wash- ington, D.C., U.S.A. — price 15 cents. " Telephone Construction Methods and Cost " by Clarence Mayer, published by Myron C. Clark Pub'g Co., 527 South Dearborn St., Chicago, 111.— price, $3. " Electrical Instruments and Telephones of the Signal Corps," issued by the United States Army Signal Corps, sold1 by the Superintendent of Documents, Wash- ington, D.C., U.S.A. — price, 65 cents. " Instruction in Army Telegraphy and Telephony," Vol. II, issued by the General Staff, War Office, 'Great Britain, obtainable from the Department of Militia and Defence, Ottawa — price, 50 cents. 200 METHODS OF COMMUNICATION FOR FOREST PROTECTION 3 — PREPARATION AND PRESERVATION OF POLES The following books have been issued by the United States Forest Service, aiiu may be procured from the Superintendent of Documents, Washington, D.C., U.S.A., at the prices indicated: — " Prolonging the Life of Telephone Poles " (reprint from the Year Book of the United States Dept. of Agriculture, 1905) — price, 5 cents. " Seasoning of Telephone and! Telegraph Poles," United States Forest Service Circular 103 — price, 5 cents. " Brush and Tank Pole Treatment," United States Forest Service Circular 104— price, 10 cents. " Test of Eocky Mountain Woods for Telephone Poles " — price, 5 cents. " Preservative Treatment of Poles," United States Forest Service Bulletin 84— price, 15 cents. 4 — MILITARY SIGNALLING AND TELEPHONY *" Training Manual — Signalling" (provisional 1915), issued by the General Staff, War Office, Great Britain; obtainable from the Department of Militia and Defence, Ottawa — price, 25 cents. " Signalling " by E. J. Solano, published by John Murray, Albemarle 'St., London, W., England — price, 25 cents. *" Manual of Visual Signalling, 1906," issued by the 'Signal Corps, United States Army, sold by the Superintendent of Documents, Washington, D.C., U.'S.A. — price, 35 cents. *" Electrical Instruments and Telephones of the United States 'Signal Corps," sold by the Superintendent of Documents, Washington, D.C., U.S.A. — price, 65 cents. " Instructions in Army Telegraphy and Telephony," Vol. 1, by the General Staff, War Office, Great Britain, obtainable from the Department of Militia and Defence, Ottawa— price, 50 cents. *" Field Telephones for Army Use" by E. J. Stevens, published by Crosby, Lockwood & 'Sons, London, England — price, $1. *" Field Equipment for Signal Troops," issued by the Signal Corps, United States Army, obtainable from the Army Signal School, Fort Leavenworth, Kansas, U.S.A. — price, 25 cents. " The Buzzer and Other Devices for Induction Telegraphy," issued by and obtain- able from the same authorities as the preceding — price, 25 cents. *" Signal Book, United States 'Army " 1916, sold by the Superintendent of Docu- ments, Washington, D.C., U.'S.A. — price, 20 cents. 5 — TELEPHONE TROUBLES *Hyde's " Telephone Troubles and How to Find Them," published' by W. H. Hyde & Co., Milwaukee, Wisconsin, U.S.A. — price, 25 cents. NOTE. — 'Most of the books on Telephone 'Science and Line Construction listed herein contain chapters on the location and clearing of trouble. 6 — SPECIALIZED FIRE PROTECTION *" Fire Protection in District ~N~o. 1— Misc. Pub. 0-7," issued by the United States Forest Service, sold by the 'Superintendent of Documents, Washington, D.C., U.S.A. — price, 15 cents. *" National Forest Fire Protection Plans," issued by the United 'States Forest Service, sold by the Superintendent of Documents, Washington, D.C., U.'S.A.- — price, 'IB cents. APPENDIX C— TELEPHONE COSTS, 201 7 — PERIODICALS " Telephony " (weekly) published by Telephony Publishing Co., 341 Monadnock Block, Chicago, 111., U.'S.A. — price, $3 per year. " Western Electric 'News " (monthly) published by the Western Electric Co., (company organ). 3 — TMADE CATALOGUES AND HANDBOOKS " Handbook of Insulated Wires and Cables " issued by Phillips Insulated Wire Co., Pawtucket, R.I., U.S.A. " The Simplex Manual " issued by the 'Simplex Wire and Cable Co., 201 Devon- shire St., Boston, Mass., U.S.A. *" Wire in Electrical Construction ' 'issued by John A. Roebling's Sons Co.. Trenton, N J., U.S.A. " Electrical Wires and Cables " issued by the American 'Steel & Wire Co., Montreal, Quebec. " Northern Electric Telephone Apparatus and Supplies, Catalogue No. 3 " issued by the Northern Electric Co., Montreal, Quebec. (*) The books and government documents marked with this symbol will be found particularly suited to those who have made no previous study of telephone science but desire to secure some elementary knowledge of the instruments and of signalling methods in general, with the use that may be made of rapid means of communication in forest protection. A great deal of useful information may be secured from the trade catalogues issued by the various manufacturers of telephones and telephone supplies and also by the manufacturers of iron and copper wire. These will always he furnished gladly on application, are nearly always profusely illustrated, and often contain much valuable data that is available nowhere else. APPENDIX C TELEPHONE COSTS 1 — FACTORS INVOLVED IN THE ESTIMATION OF COSTS OF POLE AND TREE TELEPHONE LINES The cost of forest-protection telephone lines depends upon so many variable factors that general statements are of very little value. Particularly is this true since the beginning of the European War. Materials and equipment have increased enor- mously in price, some have even become unobtainable and great delays in delivery must be expected in nearly all supplies. Labour has also both increased in price and to a certain extent decreased in quality. As in other construction work, estimates of supplies1 must be based on quotations and freight rates to point of delivery. Esti- mates of transportation away from railways must be based on daily cost of transport equipment, a»verage load, and average daily trip. Estimates of labour must be based on daily wage scale with proper allowance for board, and a knowledge of what con- stitutes a reasonable day's task under the existing conditions that to a certain extent differ with each project. This can only be done properly 'by a study of conditions along the proposed route, coupled with an accurate knowledge of actual costs on similar projects. Classified project costs are being accumulated by the Forestry Branch but as yet are not available for the general information of the field staff. 202 METHODS OF COMMUNICATION FOR FOREST PROTECTION In preparing an estimate for a telephone line, the costs should be classified under the heads shown in the following schedule: — Estimating Cost of Pole Lines — (a) Survey of route. (&) Tools. (c) Line materials. (1) Wire. (2) Insulators, brackets, and nails. (3) Poles. (4) Guys, braces and miscellaneous. (d) Station materials. (e) Transportation. (1) Wire and miscellaneous supplies. (2) Poles. (3) Camp moving. (/) Line clearing:. (1) Cutting. (2) Burning. (g) Line construction. (1) Digging holes. (2) Setting poles. (3) Pulling 'wire. (4) Tying in. (5) Miscellaneous adjustments, guys, etc. (ft) Station installations. (1) Outside work. (2) Inside work. 2 — Estimating Costs of Tree Lines — (a) Survey of route. (&) Spotting trees. (c) Tools. (d) Line materials. (1) Wire. (2) Insulators and staples. (3) Miscellaneous and poles (if any), (e) Station materials. (/) Transportation. (1) Wire and insulators. (2) Camp moving. (g) Line clearing. (1) Cutting. ( 2 ) Burning. (h) Line construction. (1) Pulling wire. (2) Tying in. (3) Pulling slack. (4) Setting poles (if any). (i) Station installation. (1) Outside work. (2) Inside work. 2— APPROXIMATE COSTS OF SUPPLIES AND AVERAGE TIME REQUIRED FOR VARIOUS OPERA- TIONS IN TELEPHONE LINE CONSTRUCTION 'All figures based on quotations in Prairie Provinces prior to the European War) 1 — Supplies — (a) Tools (per ten-man crew). (1) For pole line, $200. (2) For tree line, $120. (3) For station work, $25. (&) Line materials (per mile). (1) Wire, No. 9 B.W.G., $12. (2) Insulators, etc., $2. (3) Poles, 25 feet, $18 up. (4) Miscellaneous, $1 up. (c) Station materials each, $15. 2 — Transportation — This is a cost that depends so much on local condition that no average figure has any value. The weight to be transported may be determined from -the lists in Appendix A. 3 — Spotting Trees — (a) Very open timber — 2 men, 2 miles per hour. (&) Very dense timber — 3 men, i mile per hour. 4 — Line Clearing — This is a cost that depends entirely on local conditions. In general, right of way for tree lines should seldom cost over $25 per mile for clearing, with labour at 30 cents per hour, but under exceptionally un- favourable conditions may run to $45 per mile. In fair-sized timber with little underbrush the cost may be as low as $2 per mile. For pole lines the cost will be materially higher, depending on the width of clearing. 5 — Line Construction, Tree lines — (a) Pulling wire. (1) Best — 2 men and 1 horse, 1 mile per hour. (2) Worst — 5 men, J mile per hour. (6) Tying in. (1) Best — 1$ miles per man, per day. (2) Worst — \ mile per man, per day. (c) Pulling slack — 2 men, 1 mile per hour. On pole lines all these costs will be reduced from 15 to 50 per cent. 6 — Erecting Poles, 2>2J or 2>5 feet — (a) Digging holes. (1) Soft ground — 1 man, 3 holes per hour. (2) Medium ground — 1 man, 1'hole per hour. (3) Hard ground — 1 man, § hole per hour. (&) Setting poles — 3 men, 2J poles per hour, (c) Attaching lightning-rods — 1 man, 4 rods per hour. (d) Guying and anchoring — 2 men, 2 an- chors per day. 7 — Station Installation — (a) Best — 1 man, 3 hours (indoor). 2 men, 2 hours (outdoor). (&) Worst — 1 man, 5 hours (indoor). 2 men, 4 hours (outdoor). APPENDIX D REGULATIONS OF THE BOARD OF RAILWAY COMMISSIONERS FOR CANADA REGARDING WIRE CROSSINGS No. 10 — WIRES ERECTED ALONG OR ACROSS RAILWAYS By section 7 of chapter 22, 1-2 George V (1911), section 4 of chapter 50 of the Statutes of 1910 was repealed, and the following was enacted as subsection 5 of section 246 of the Railway Act:— " 5 An order of the Board shall not be required in cases in which wires or other conductors for the transmission of electrical energy are to be erected or maintained over or under a railway, or over or under wires or other conductors for the transmission of electrical energy with the consent of the railway company or the company owning or controlling such last-mentioned wires or conductors in accordance with any general regulations, plans, or specifications adopted or approved by the Board for such purposes." NOTE. — The above applies to construction across the railway only. Where the wires or other conductors are to be erected along the railway, an order of the Board is necessary. General Order No. 231 of the Board of Railway Commissioners In the matter of section 21+6 of the Railway Act, as amended l>y chapter 37 of the Acts 7-8 George V, section 4, for the carrying of wires and cables along or across the tracks of railway companies under the jurisdiction of the Board. Upon the report and recommendation of the Electrical Engineer of the Board, — It is ordered: — 1 That the conditions and specifications set forth in the schedule hereto annexed, under the heading, " Rules for Wires erected along or across Railways," be, and the same are hereby, adopted and confirmed as the conditions and specifications applicable to the erection, placing, or maintaining of electric lines, wires, or cables along or across all railways subject to the jurisdiction of the Board, part 1 being applicable where the line or lines, wire or wires, cable or cables, is or are carried along or over the railway; part 2 being applicable where the line or lines, wire or wires, cable or cables, is or are carried under the railway. 2 That any order of the Board granting leave to erect, place, or maintain any line or lines, wire or wires, cable or cables, along or across the railway and referring to " Rules for Wires erected along or across Railways," shall be deemed as intended to be a reference to the conditions and! specifications set out in that part of the said schedule which is applicable to the mode of crossing authorized. 3 That any order of the Board granting leave to erect, place, or maintain any line or lines, wire or wires, cable or cables, along or across any railway subject to the jurisdiction of the Board, shall, unless otherwise expressed, be deemed to be an order for leave to erect, place, and maintain the same according to the conditions and specifi- cations set out in that part of the said schedule applicable thereto, which conditions and specifications shall be considered as embodied in any such order without specific reference thereto, subject, however, to such change or variation therein or thereof as shall be expressed in such order. 203 204 METHODS OF COMMUNICATION FOR FOREST PROTECTION 4 That the general order of the Board No. 113, dated November 5, 1913, approv- ing of " Rules for wires crossing railways," and the conditions and specifications adopted thereby, be, and the same is hereby, rescinded. H. L. DRAYTON, May 6, 1918. Chief Commissioner. Schedule NOTICE TO APPLICANTS "When the interested company's consent cannot be procured and an application to the Board becomes necessary, send to the Secretary of the Board (postage free) with the application, three copies of a sketch or drawing about 8 by 10 in. showing: — (a) The location of the poles or towers, or the location of the underground con- duit in relation to the track; the dimensions of the poles or towers; and the material or materials of which they are made. (fe) The proposed number of wires, or cables, the distance between them and the track and the method of attaching the conductors to the insulators. (c) The location of all other wires adjacent or to be crossed, and their supports. (d) The maximum potential, in volts, between wires, the potential between wires and the ground, and the maximum current, in amperes, to be transmitted. (e) The kinds and sizes of the wires or conductors in question. (/) On circuits of 10,000 volts, or over, the method of protecting the conductors from arcs at the insulators. (#) The number of insulators supporting the conductors. (See also " J" in Specifications.) N.B. — Place a distinguishing name, number, date, and signature upon the draw- ing. Mark the exact location of the lines or wires upon the drawing, by stating the distance in miles from the nearest railway station — N., E., S. or W. — so that this point can readily be identified. STANDARD CONDITIONS AND SPECIFICATIONS FOR WIRE CROSSINGS PART I — OVER-CROSSINGS Conditions 1 The applicant shall, at its or his own expense, erect and place the lines, wires, cables, or conductors authorized to be placed along or across the said railway, and shall at all times, at its own expense, maintain the same in good order and condition and at the height shown on the drawing, and in accordance with the specifications hereinafter set forth, so that at no time shall any damage be caused to the company owning, operat- ing or using the said railway, or to any person lawfully upon or using the same, and shall use all necessary and proper care and means to prevent any such lines, wires cables, or conductors from sagging below the said height. 2 The applicant shall at all times wholly indemnify the company owning, operat- ing, or using the said railway, of, from, and against all loss, cost, damage, and expense to which the said railway company may be put by reason of any damage or injury to persons or property caused by any of the said wires or cables or any works or appli- ances herein provided for not being erected in all respects in compliance with the terms and provisions of this order, as well as any damage or injury resulting from the imprudence, neglect, or want of skill of the employees or agents of the applicant. 3 No work shall at any time be done under the authority of this order in such a manner as to obstruct, delay or in any way interfere with the operation or safety of the trains or traffic of the said railway. 4 Where, in effecting any such line or wire construction, it is necessary to erect poles between the tracks of the railway, the applicant, before any work is begun, shall APPENDIX D— CROSSING REGULATIONS 205 give the railway company owning, operating, or using the said railway at least seventy- two hours' prior notice thereof in writing, and the said railway company shall be entitled to appoint an inspector, under whose supervision such work shall be done, and whose wages, at a rate not to exceed three dollars per day, shall be paid by the appli- cant. When the applicant is a municipality and the work is on a highway under its jurisdiction, the wages of the inspector shall be paid by the railway company. 4^ (a) It shall not, however, be necessary for the applicant to give prior notice in writing to the railway company as above provided1 in regard to necessary work to be done in connection with the repair or maintenance of the lines or wires when such work becomes necessary through an unforeseen emergency. 5 Where the wires or cables are to be erected at the railway and carried above, below, or parallel with existing wires, either within the span or spans to be constructed at the railway or within the spans next thereto on either side, such additional pre- cautions shall be taken by the applicant as the Engineer of the Board shall consider necessary. 6 Nothing in these conditions shall prejudice or detract from the right of the company owning, operating, or using the railway to adopt at any time the use of electric or other motive power, and to place and' maintain along, over, upon, or under its right of way, such poles, lines, wires, cables, pipes, conduits, and other fixtures and appliances as may be necessary or proper for such purposes. Liability for the cost of any removal, change in location or construction of the poles, lines, wires, ca'bles or other fixtures or appliances erected by the applicant along, ovsr or under the tracks of the said railway company, rendered necessary by any of the matters referred to in this paragraph, shall be fixed by the Board on the application of any party interested. 7 Any disputes, arising between the applicant and the said railway company as to the manner in which the said1 wires or cables are to be erected, placed or main- tained, used or repaired, shall be referred to the Engineer of the Board, whose decision shall be final. 8 The wires or cables of the applicant shall be erected, placed and maintained in accordance with the drawings approved by the Board and the specifications following. If the drawing and1 specifications differ the latter shall govern unless a specific state- ment to the contrary appears in the Order of the Board. 9 In every case in which the line of a railway -company is to be constructed along or under the wires or cables of a telegraph or telephone company, the construc- tion of the telegraph or telephone line or lines of the company shall be made to con- form to the foregoing specifications, and any changes necessary to make it so conform shall be made by the telegraph or telephone company at the cost and expense of the railway corrpany. OVERHEAD LINES Specifications A Labelling of poles. — Poles, towers, or other wire-supporting structures on each side of and adjacent to railway crossings, to be equipped with durable labels showing (a) the name of the company or individual owning or maintaining them, and (ft) the maximum voltage between conductors; the characters upon the labels to be easily distinguished from the ground. B Separate lines. — Two or more separate lines for the transmission of electrical energy shall not be erected or maintained in the same vertical plane. The word " lines," as here used, to mean the combination of conductors and! the latter's support- ing poles, or towers and fittings. 0 Location of poles, etc. — Pole% towers, or other wire-sup'wrting structures to be located generally a distance from the rail not less than equal to the length of the poles or structures used. Poles, towers, or other wire-supportin? structures must 206 METHODS OF COMMUNICATION FOR FOREST PROTECTION und'er no consideration be placed less 'than 12 ft. from the rail of a main line, or less than 6 ft. from the rail of a siding. At loading sidings sufficient space to te left for driveway. D Setting and strength of poles. — Poles less than 50 ft. in length to be set not less than 6 ft. and poles over 50 ft. not less than 7 ft. i-n solid ground. Poles with side strains to be reinforced with braces and guy wires. Poles to be at least 7 in. in diameter at the top — mountain cedar poles to be at least 8 in. at the top. In soft ground poles must be set so ,as to obtain the same amount of rigidity as would be obtained by the above specifications for setting poles iii solid ground. When the line is located in a section of the country where grass or other fires might burn them, wooden poles to be covered with a layer of some satisfactory fire-resisting material, such as concrete at least two in. thick, extending from the butt of the pole for a distance of at least 5 ft. above the level of the ground. Wooden structures to have a safety factor of 5. E Setting and strength of other structures. — Towers or other structures to be firmly set upon stone, metal, concrete or pile footings or foundations. Metal and concrete structures to have a safety factor of 4. E Length of Span. — Span must be as short as possible consistent with the rules of setting and locating of poles and towers. G Fittings of wooden poles for telegraph, telephone, or similar low-tension lines. — The poles at each side of a railway must be fitted with double cross-arms', dimensions not less than 3 in. by 4 in., each equipped with 1^-in. hardwood pins, nailed in arms, or some stronger support and with suitable insulators; cross-arms to be securely fastened to the pole in a gain by not less than a f-in. bolt through the pole; arms carryiiig more than two wires or carrying cable must be braced by two stiff iron or substantial wood braces fastened to the arms by -§-in. or larger bolts, and to the pole by a f-in or. larger bolt. H Fittings of all poles, towers, or other structures.— All wire-supporting structures to be equipped with fittings satisfactory to the Engineer of the Board. I Guards. — Where cross-arms are used, an iron hook guard to be placed on the ends of and securely bolted to each. The hooks shall be so placed as to engage the wire in the event of the latter's detachment from the insulators. J Insulators. — All wires or conductors for the transmission of electrical energy along or across a railway to be supported by and securely attached to suitable insula- tors. Wires or conductors in 10,000-volt (or higher) circuits, to be supported by insula- tors capable of withstanding tests of two and one-half times the maximum voltage to be employed under operating conditions. An affidavit describing the tests to which the insulators have been subjected and the apparatus employed in the tests shall be supplied by the applicant. The tests upon which reports are required are as follows: — Ja Puncture or rupture test. — The insulators having been immersed in water for a period of seven days, immediately preceding and ending at the time of the test, to be subject for a period of five minutes to a potential of two aiid one-half (2-5) times the maximum potential of the line upon which they are to.be installed. Jb Flash-over test. — State the potentials that were employed to cause arcing or flashing across the surface of the insulator between the conductor and the insulator's point of support when the surface was (1) dry, and (2) wet. K Height of wires (a) Low-tension conductors. — The lowest conductor must not be less than 25 ft. from top of rail for spans up to 145 ft.; 2£ ft. additional clearance APPENDIX D— CROSSING REGULATIONS 207 of rails or other wires must be given for every 20 ft. or fraction thereof additional length of span. The words " low-tension," as here used, to mean conductors for telegraph, telephone, and kindred signal work, as well as conductors connected with grounded secondary circuits of transformers below 350 volts. Kb All primary conductors, ungrounded secondaries, and railway feeders to be maintained at least 30 ft. above the top of rail — except where special provisions are made for trolley wires. Kc High-tension conductors, those between which a potential of 10,000 volts or over is employed, to be maintained at least 35 ft. above the top of rail. L Clearances. — 'Safe clearances between all conductors to be maintained at all times. The following distances to be provided wherever possible; at least 3 ft. clear- ance from low-tension wires; at least 5 ft. between low-tension wires, primaries, ungrounded secondaries, and railway feeders employing less than 10,000 volts; at least 10 ft. between high-tension wires and all other lines. M Guy wires. — 'Guy wires at railway crossings to be at least as strong as 7-strand No. 1'6 'Stub's or New British 'Standard gauge galvanized steel wire, and to be clearly indicated as guy wire on the drawing accompanying the application. One or more strain insulators to be placed in all guy wires; the lowest strain insulator to be not less than 8 ft. above the ground. Na Wires and other conductors. — Where open telephone, telegraph, signal or kindred low-tension wires are strung across a railway this stretch to consist of copper wire, or copper-clad steel wire, not less than No. 13 New British Standard .gauge, -09'2 in. in diameter. Wire is to be securely tied to insulators by a tie wire not less than 20 in. in length and of the same diameter as the line wire, Nb Where No. 9 iB.W.G., or larger, galvanized iron or steel wire is employed in a circuit, and where there is no danger of deterioration from smoke or other gases, the use of this wire may be continued at the crossing. Nc Where a number of ru'bber-covered wires are strung across a railway they may be made up into a cable by being twisted on each other or otherwise held together and the whole securely fastened to the poles. Nd Wires or other conductors for the transmission of electrical energy for pur- poses other than telegraph^ telephone, or kindred low-tension signal work, to be com- posed of at least seven strands of material having a combined tensile strength equiva- lent to or greater than iNo. 4 B. & S. gauge hard-drawn copper wire. These con- ductors to be maintained above low-tension wires at the crossing, to be free from joints or splices, and to extend at least one full span of line beyond the poles or towers at each side of the railway. Ne Wires or other -conductors subject to potentials of 10,000 volts or over, to be reinforced by clamps, servings, wrappings, or other protection at the insulators to the satisfaction of the Engineer of the Board. Nf Conductors for other than low-tension work to have a factor of safety of 2 when covered with ice or sleet to a depth of 1 in. and subjected to a wind pressure of 8 pounds per square ft. on the ice-covered diameter. Ng All conductors to be dead-ended or so fastened to their supporting insulators at each side of the crossing that they cannot slip through their fastenings. 0 Positions of wires. — Wires or conductors of low potential to 'be erected and maintained below those of higher potential which may be attached to the same poles or towers. P Trolley wires. — Trolley wires at railway crossings to be provided with a trolley guard so arranged as to keep the trolley wheel or other rolling, sliding or scraping device in electrical contact. The trolley wire, trolley guard, and their supports to be maintained at least 22 ft. 6 in. above the top of the rails. 208 METHODS OF COMMUNICATION FOR FOREST PROTECTION Q Cable. — Cable to be carried on a suspension wire at least equivalent to seven strands of No. 13 Stub's or New British Standard gauge galvanized steel wire. When cross-arms are used, suspension wires to be attached to a |-in. iron or stronger hook, or when fastened to poles to a malleable iron or stronger messenger hanger bolted through the poles, the cable to be attached to the suspension wire by cable clips not more than 20 in. apart. Rubber insulated cables of less than f in. in diameter may be carried on a suspension wire of not less than seven strands of No. 16 Stub's or New British Standard gauge galvanized steel wire. The word " cable " as here used, to mean a number of insulated conductors bound together. PART II — UNDERGROUND LINES Conditions 1 The line or lines, wire or wires, shall be carried along or across the railway in accordance with the approved drawing, and a pipe or pipes, conduit or conduits, cable or cables shall, for the whole width of the right of way adjoining the highway, be laid at the depth called for by, and shall be constructed and maintained in accord- ance with the specifications hereinafter set forth. 2 All work in connection with the laying and maintaining of each pipe, conduit or cable and the continued supervision of the same shall be performed by, and all costs and expenses thereby incurred be borne and paid by the applicant; but no work shall at any time be done in such a manner as to obstruct, delay or in any way inter- fere with the operation or safety of the trains, traffic or other work on the said rail- way. f 3 The applicant shall at all times maintain each pipe, conduit or cable in good order and condition, so that at no time shall any damage be caused to the property of the railway company or any of its tracks be obstructed, or the usefulness or safety of the siame for railway purposes be impaired, or the full use and enjoyment thereof by the said railway company be in any way interfered with. 4 Before any work of laying, removing, or repairing any pipe, conduit or cable is begun, the applicant shall give to the railway company at least seventy-two hours prior notice thereof, in writing, accompanied by a plan and profile of the part of the railway to be affected, showing the proposed location of such pipe or conduit and works contemplated in connection therewith, and the said railway company shall be entitled to appoint an inspector to see that the applicant, in performing said work, complies, in all respects, with the terms and conditions of this order, and whose wages, at a rate not exceeding $3 per day, shall be paid by the applicant. When the applicant is a municipality and the crossing is on a highway under its jurisdiction the wages of the inspector shall be paid by the railway company. 4a It shall not, however, be necessary for the applicant to give prior notice in writing to the railway company, as above provided, in regard to necessary work to be done in connection with the repair or maintenance of the line when such work becomes necessary through an unforeseen 'emergency. 5 The applicant shall, at all times, wholly indemnify the company owning, operat- ing, or using the said railway of, from, and against all loss, costs, damage, and expense to which the said railway company may be put by reason of any damage or injury to person or property caused by any pipe, conduit, or cable, any works or appli- ances herein, or in the order authorizing the work provided for, not being laid and constructed in all respects in compliance with the terms and provisions of these con- ditions, or if, when so constructed and laid, not being at all times maintained and kept in good order and condition and in accordance with the terms and provisions of said order, or any order or orders of the Board in relation thereto, as well as any damage or injury resulting from the imprudence, neglect, or want of skill of any of the employees or agents of the applicant. APPENDIX E— STANDARD SPECIFICATIONS 209 6 Nothing in these conditions shall prejudice or detract from the right of any company owning or operating or using the said railway to adopt, at any time, the use of electric or other motive power, and to place and maintain upon, over, and under the said1 right of way such poles, wires, pipes, and other fixtures and appliances as may be necessary or proper for such purposes. Liability of the cost of any removal, change in location or construction of the pipes, conduits, wires, or cables constructed or laid by the applicant rendered necessary by any of the matters referred to in this para- graph, shall be fixed by the Board on the application of the party interested. 7 Any dispute arising between the applicant and the company owning, using or operating said railway as to the manner in which any pipe or conduit, or any works or appliances herein provided for, are being laid, maintained, renewed, or repaired, shall be referred to the Engineer of the Board, whose decision shall be final and binding on all parties. UNDERGROUND LINES Specifications AA Conduit. — Vitrified clay, creosotei wood, metal pipe, armoured cable or fibre conduit may be used. BB Depth. — The excavation to be of sufficient depth to .allow the top of the d*uct to be at least three ft. below the bottom of the ties of the railway track. CO Laying. — The conduit or duct to 'be laid on a base of 3 in. of concrete, mixed in proportion, 1 of cement, 3 of sand, and 5 of broken stone or gravel. Where stone is used, such stone is to be of a size that will permit of its passing through a 1-in. ring. After dlucts are laid, the whole to be encased to a thickness of 3 in. on top and sides in concrete mixed in the same proportions as above. Where the track is on ,an embankment a pipe may be driven through the latter. DD Filling in. — The excavation must be filled' in slowly and well tamped on top and side. EE Guard. — The excavation must at all times be safely protected by the appli- cant. APPENDIX E FORESTRY BRANCH STANDARD SPECIFICATIONS 1— Specifications for Galvanizing (a) General. — All iron and steel materials requiring galvanizing shall be pre- pared according to the following requirements : — The galvanizing shall consist of a deposition of zinc laid on by either the hot or electric process ; this coating shall be evenly and uniformly applied over the entire surface; all holes, grooves, threads, or other irregularities of surface shall be thor- oughly coated, and there shall be no excess deposit, rough places, or other imperfec- tions. All galvanizing of parts intended to fit together shall be so performed that such parts can be readily and properly assembled. (b) Test.— All galvanized equipment shall be required to pass the following test, a reasonable quantity of each shipment not to exceed 10 per cent being selected for test and the shipment passed or rejected on the basis of test: — The sample snail be immersed in the standard solution of copper sulphate for one minute, removed, wiped dry, and! cleaned. This process shall be repeated until 79211—14 210 METHODS OF COMMUNICATION FOR FOREST PROTECTION four (4) immersions in all have been made, and thereafter if any deposits of copper or any red spots appear on the sample, or if the galvanizing appears corroded or removed, the sample shall be considered defective and the shipment represented by the sample rejected. / (c) Standard Solution. — The standard solution of copper sulphate shall consist of a solution of commercial copper sulphate crystals in water having a specific gravity of 1-185 at 70° F. The" temperature of the solution shall not exceed 70° F. nor fall below 60° F. while the sample is beinig tested. 2 — Specifications for Galvanized-iron Telephone Wire General description. — The finished product desired under these specifications consists of galvanized B.B. wire as hereinafter specified. Finish. — The wire shall be cylindrical in form and free from scales, inequali- ties, flaws, splints, and other imperfections. The finish of the wire shall be in accordance with the best commercial practice. Each coil shall be warranted not to contain any weld, joint, or splice in the rod before drawn. Galvanizing. — The wire shall be well galvanized in accordance with the speci- fications for the galvanizing of iron and steel given in Specifications No. 1. ELECTRICAL REQUIREMENTS Electrical resistance. — The resistance of the wire in ohms per mile at a tempera- ture of 68° F. shall not exceed the quotient arising from dividing the constant number, fifty-six hundred (5,600), by the weight of ihe wire in pounds per mile. MECHANICAL REQUIREMENTS Dimensions. — The diameter of the galvanized wire shaH be within the limits given in the following table: — Gauge No., B.W.G. Diameter of galvanized wire, in inches Gauge No., B.W.G. Diameter of galvanized wire, in inches Maximum Gauge Minimum Maximum Gauge Minimum 6 8 0-207 0-169 0-152 0-203 0-165 0-148 0-198 0-161 0-144 10... 12 14 0-138 0-112 0-086 0-134 0-109 0-083 0-130 0-105 0-080 9 . .. Breaking weight. — The breaking weight of the wire shall not be less than two and eight-tenths (2-8) times the weight of the wire in pounds per mile. Torsion. — The wire shall be capable of withstanding at least fifteen twists in a length of 6 in. Coils. — The length of the wire in each coil shall be as follows: No. 6 B.W.G., approximately J mile; Nos. 8, 9, 10, 12 and 14 B.W.G., approximately i mile. In the case of wire less than 0-134 in. in diameter, one-third of the coils may have two pieces to a coil, joined by the ordinary twist joint carefully soldered and galvanized. In the case of wire 0-134 in. in diameter, and larger, each coil may consist of two pieces only, joined by the ordinary twist joint carefully soldered and galvanized. Binding. — Each coil of wire shall be securely bound in at least four places with galvanized iron wire. A tag shall be attached to each coil giving the size and grade of wire in the coil. APPENDIX E— STANDARD SPECIFICATIONS 211 3— Specifications for Hard-drawn Copper Telephone Wire General. — The material shall be copper of such quality and purity that when drawn hard it shall have the properties and characteristics herein required. The manufacture, workmanship, and finish must be in accordance with the best commercial practice. Manufacture. — Each coil shall be drawn in one length and be exempt from joints or splices. All wire shall be truly cylindrical and shall conform to gauge within the limits of variation permitted by these specifications. It must not contain any scale, inequalities, flaws, cold shuts, seams, or other imperfections. MECHANICAL AND ELECTRICAL REQUIREMENTS Diameter in mils Weights per mile in pounds Breaking wts. in pounds Wts. of coils, pounds Conduc- tivity ll o -o 1 3 imum imum 1 "3 | imum •|'3 ctual imum s g-g CO a imum imum 1 !mum .58 ll '£"" if 0 & 1 .a 1 1 S ^g 's I e S e S Q) O fV*3 B.W.G. % % 8 128 130 127 260 264 258 818 800 63,100 219 151 97 96 40 1-05 B. & S.G. 10 101-9 102-8 101-0 165-0 168-0 162-0 540 519 64,800 218 152 97 96 40 0-99 12 80-0 81-2 79-3 102-6 105-7 100-8 334 327 66,500 72 52 97 96 44 0-94 14 64-0 65-0 63-0 65-0 67-5 63-0 220 212 68,200 97 96 47 0-91 Shipping. — The wire shall be made up into coils the eye of which shall have a maximum diameter of 22 in. and a minimum diameter of 18 in., and shall be securely tied by not less than four separate pieces of strong twine, and shall be protected by a sufficient wrapping of burlap so that the wire may not be injured during transporta- tion. The wrappings shall be placed upon the wire bundles, after they have been coiled and secured by the twine. Each coil shall have its gauge, length, and weight plainly and indelibly marked upon two brass tags which shall be secured to the coil, one inside the wrapping and the other outside. 4 — Specifications for Emergency Wire General. — This wire will be used under all climatic and weather conditions and will be laid out on the ground, or on trees, in continuous lengths not exceeding 30 miles, and without the use of insulators. The quality of the material used and the method of manufacture shall be such as to ensure for the wire the properties herein specified. Conductor. — This wire shall have a conductor consisting of ten strands of No. 30 B. & S. gauge hard-drawn copper wire twisted together, the twists per foot not to be less than eight and not more than ten. Hard-drawn Copper Wire. — The hard-drawn copper wire shall be free from bends, cuts of any dimensions, nicks, splits or splinters, spills, grooves, scraped, surface, wavy surface, flat-sided or oval wire, corrosion, or any irregularities. The diameter of No. '60 hard-drawn copper wire shall not be greater than -01013 in. nor less than -00993 in. Covering.— A double reverse serving of cotton shall be applied to the twisted conductor so as to form a close, smooth covering. Weather-proofing.— The cotton covering shall be thoroughly saturated with a per- manent weather-proof compound of such a nature as to preserve the strength of the 79211— 14i 212 METHODS OF COMMUNICATION FOR FOREST PROTECTION cotton wrapping, shall not act injuriously thereupon, and shall be insoluble in water. The compound shall adhere firmly to the cotton covering and shall not drop or run when the finished wire is subjected to a temperature of 150° F. for thirty minutes, and shall not crack when the wire is subjected to a temperature of 10° F. for thirty minutes. The diameter of the completed wire shall not be more than -048 in. and not less than -043 in. Spooling, — The wire shall be evenly wound on wooden spools weighing approxi- mately three-quarters of a pound. The inner end of the wire shall be brought out through the spool head. The length of the wire shall be 2,640 ft. plus 100 ft. The exact length of the wire shall be marked on the spool. The wire on each spool shall be one continuous length. •Splices. — Spliced joints shall be equal to or stronger than the wire itself and shall be so made as not to materially increase the diameter of the conductor at the point where the splice occurs. Weight per mile. — The weight per mile of the finished wire shall not exceed nineteen and a half (19-5) pounds and shall not be less than seventeen and a half (17-5) pounds. This does not include the weight of the wooden spool. Tensile Strength. — Tests shall be made on wire from the ends of which the insula- tion has been removed. The finished wire shall have a minimum breaking weight of forty-five (45) pounds and a minimum elongation of one-half of 1 per cent in a length of 2 feet. Resistance. — The resistance of this wire shall not be more than 60 ohms per mile at a temperature of 68° F. 5 — Specifications for Rubber-covered Copper Wire General. — The quality of the material used must be of the best, and the manu- facture, workmanship, and finish must be in accordance with the best commercial practice. Manufacture. — The conductor shall be in one continuous length, cylindrical in section, and uniformly drawn, so that the variation over or under the specified diameter shall not exceed one (1) mil (one one-thousandth of an^ inch). It shall be uniform in quality, free from factory joints, scales, splints, flaws, and other imperfections. To ensure the removal of defects from the conductor the manufac- turer shall cut off 2'5 ft., or ,as much more as may be necessary, from each end of every coil. Each conductor before being insulated shall be thoroughly and uniformly linned. The tin coating nost conform to the following requirements: The tinned conductor shall be immersed in a current of pure hydrogen sulphide gas, saturated with water vapour at a temperature of not less than 75°F. and not more than 79°F. for four hours. At the end of this time the conductor must exhibit no signs of blackening. Insulation. — The tinned conductor shall be evenly and smoothly covered with vulcanized rubber of the best quality, which is impervious to moisture, or some other approved weather-proof, insulating compound to such a thickness as hereinafter specified. The dielectric shall adhere firmly to the conductor and shall not act injuriously upon it. The wire shall be well centred in the dielectric. The dielectric shall not soften sufficiently to allow decentralization at a lower temperature than 130° F. APPENDIX E— STANDARD SPECIFICATIONS 213 The insulated' conductor shall 'be sufficiently flexible to stand being twistel three times about itself, left for at least sixteen hours, and untwisted without the dielec- tric showing any signs of rupture. Electrical Requirements. — The insulation test shall be made on the outside dis- tributing conductor whilst in water, the conductor having been previously submerged in water for at least twelve hours prior ,to the test. All conductors, No. 16 B & S. gauge and over, shall show an insulation resistance of not less than 500 megohms per mile; and conductors under No. 16 B. & S. gauge shall have an insulation resistance of not less than 250 megohms per mile. The temperature at which test is to be made shall not be less than 60°F. nor more than 70°F. The test for insulation resistance shall be made with an electro-motive force of not more than 550 volts, the insulation resistance to be figured from the deflection obtained with the negative pole of the source of potential connection to the conductor and after an electrification of one minute. If unequal deflections are obtained with the positive and negative poles connected to the wire, the insulation shall be considered defective. Mechanical Requirements. — These include breaking weight, elongation, and braid- ing. The breaking weight for No. 14 B. & S. gauge wire shall not be less than one hundred and ninety (190) pounds; for No. 16 B. & S. gauge wire, not less than one hundred and twenty-five (125) pounds; and for No. 19 B. & S. gauge wire not less than seventy (70) pounds. The elongation in two feet 'shall not be less than 1 per cent for No. 14, No. 16, and No. 19 B. & S. gauge wires. As to braiding, each insulated conductor shall be covered writh a close, smooth braid, which shall be thoroughly impregnated with a permanent weather-proof com- pound. The impregnated braid shall then be uniformly covered with a continuous layer of the compound which shall adhere firmly to the braid. The compound shall not act injuriously on the dielectric or the braid, and shall not melt when subjected to a temperature of 125° F., nor crack at a temperature of 30° F., and shall be insoluble in water. Packing for Shipment. — The finished conductor shall be delivered in coils of one continuous piece, the eye of the coil to be about nine inches. Both ends of the coil shall be accessible. Each coil shall be securely bound with strong tape or twine in at least four separate places, and shall then be wrapped with burlap or strong paper to prevent mechanical injury during transportation. Each coil shall have its gauge and length plainly marked on two strong tags, one tag to be attached to the coil and the other to the outside of the wrapping. 6— Specifications for Glass Insulators The material desired under these specifications consists of glass insulators of the style and dimensions hereinafter described. General — 'The specifications and drawings are intended to include all instruc- tions necessary to guide the manufacturer in his work. They are intended to co- operate with and supplement each other so that any details indicated in one and not in the other shall be executed as if indicated in both. Workmanship.— All workmanship shall be of the best commercial grade. 'Material. — The insulators shall be made of transparent colourless or green glass. Dimensions. — The insulators shall be of the style and dimensions shown in the drawing attached hereto and: made part of these specifications. 214 METHODS OF COMMUNICATION FOR FOREST PROTECTION Where maximum and minimum dimensions are shown the dimensions shall be within the limts specified. Where limits are not shown the dimensions shall be approximate. The diameter of the thread shall be such that at least two revolutions of the insulator will be required to tighten it on the standard insulator gauge, and when in this position the end of the insulator gau^e shall not be more than one-eighth of an inch from the crown of the insulator. 4 threads to the inch A I Iowa ble Variations over under 0 w. 0 X »%aH o y o ld/3a" d V&" /8* Specifications 6 Design of Forestry Branch standard pony glass insulator The thread of all insulators shall be smooth and of uniform pitch. The thread, shall be well centred in the insulator so that, when in place on the standard insulator gauge, the gauge will not touch the inner surface of the petticoat. Insulators conforming in all other respects to the requirements of these specifi- cations, but having on the lower edge of ,their petticoats a series of projecting points, may be accepted under these specifications. Finish. — The insulators shall have a finish ensuring, so far as is consistent with the best commercial practice, smooth even surfaces and freedom from flaws, cracks, blow-holes, sharp edges, and other defects. 7 — Specifications for Split Tree Insulators Material. — Split tree insulators .shall be made of the best grade of insulator porcelain. Finish. — The surface shall be prown-glazed except the faces which are to be placed in contact in .attaching the insulator around the line wire. These may be left white and unglazed. The glazed finish shall be smooth, without rough spots, cracks, sharp edges, or other defects. APPENDIX E— STANDARD SPECIFICATIONS Workmanship. — All workmanship shall be of the best commercial grade. 215 Dimensions. — The insulators shall be of the type and dimensions shown in the drawing attached hereto, and made a part of these specifications. INSULATOR, Specifications 7 Design of Forestry Branch' standard split tree insulator 8 — Specifications for Cedar Poles Purchased poles not cut under the supervision of the Dominion Forestry Branch shall be required to conform to the specifications of the Northern White Cedar Asso- ciation if secured east of the Rocky mountains, or to those of the Western Red Cedar Association if secured west of the Rocky mountains. For convenience and reference extracts from these specifications are reprinted below: — Northern White Cedar Association Specifications " Sizes, 4 in., 25 ft. and upwards. Above poles must be cut from live, growing cedar timber, peeled, and reasonably well proportioned for their length. Tops must he reasonably sound, must measure in circumference as follows: seasoned1 4-in. poles, 12 in.; 5-in. poles, 15 in.; 6-in. poles, 1&J in,; 7-in. poles, 2® in. If poles are green, fresh cut, or water-soaked, then 4-in. poles must measure 12£ in.; 5-in. poles, 16 in.; 6-in. poles, 19i in. ; 7-in. poles, 22>f in. in circumference -at top end. Lengths may be one-half inch, scant for each j5 ft. in length, and six inches long for any length from 20 ft, up. "One way sweep allowable not exceeding 1 in. for every 5 ft.; for example, in a 25-ft. pole, sweep not to exceed 5 in., and in a 40-ft. pole, 8 in. Measurement for sweep shall be taken as follows: That part of the pole when in the ground (6 ft.) not being taken into account in arriving at sweep, tightly stretch a tape-line on the side of the pole where the sweep is greatest from a point 6 ft., from the butt to the upper 216 METHODS OF COMMUNICATION FOR FOREST PROTECTION surface at top, and having so done measure widest point from tape to surface of pole and if, for illustration, upon a 25-ft. pole said widest point does not exceed 5 in., said pole comes within the meaning of these specifications. Butt-rot in the centre including small ring-rot outside of the centre; total rot must not exceed 10 per cent of the area of the butt. Butt-rot of a character which plainly seriously impairs the strength of the pole above ground is a defect. Wind-twist is not a defect unless very unsightly and exaggerated. Kough, large knots, if sound and trimmed smooth, are not a defect." Western Red Cedar Association Specifications "All poles must be cut from live, growing cedar timber, peeled, knots trimmed close, butts and tops sawed square, tops must be sound and must measure as follows in circumference: — 4-in. top, 12-in. circ. 7-in. top, 22-in. circ. 9-in. top, 28-in. circ. 5-in. top, 15-in. circ. 8-in. top, 25-in. circ. 10-in. top, 31-in. circ. 6-in. top, 18-J-in. circ. " No pole shall have more than one crook and this shall be one way only, the sweep not to exceed 1 in. to every 6 ft. in length. Same to be determined in the fol- lowing manner : — Measurement for sweep shall be taken as follows : [Phat part of the pole when in the ground (6 feet) not being taken into account in arriving at sweep, tightly stretch a tape-line on the sidle of the pole where sweep is greatest, from a point 6 ft. from butt to the upper surface at top, and, having so done, measure widest point from tape to surface of pole and if, for illustration, upon a 30-ft. pole said widest point does not exceed 5 in., said pole comes within the meaning of these specifications. " Butt-rot in centre, including small ring-rot, shall not exceed 10 per cent of the area of the butt. Butt-rot of a character which impairs the strength of the pole above ground is a defect. "Large knots, if sound and trimmed smooth, are not a defect. "A perfectly sound, dead or dry streak shall not be considered a defect when it •loos not materially impair the strength of the pole." APPENDIX E— STANDARD SPECIFICATIONS 9 — Specifications for Wooden Spools for Emergency Wire 217 The spool on which the emergency wire is to be wound is to be made in accord- ance with the drawing attached hereto and made a part of these specifications. The material is to be clear, straight-grained, thoroughly seasoned pine; the manufacture Sketch of Emergency Wire Spoof Specifications 9 Design of Forestry Branch standard emergency wire spool is to be of the best grade and the spools are to be finished with two coats of shellac varnish. The weight of the finished spool should be approximately three-quarters of a pound. 10 — Specifications for Creosote The oil used shall be the best obtainable grade of coal-tar creosote, that is, it shall be a pure product obtained from coal-gas tar or coke-oven tar and shall be free from any tar, oil or residue obtained from petroleum or any other source, including coal-gas tar or coke-oven tar; it shall be completely liquid at 98° C. and shall be free from suspended matter; the specific gravity of the oil at 38°C. shall be at least 1-03. When distilled by the .common method (that is, using an 8-ounce retort, asbestos- Covered with standard thermometer, bulb 4 in. above the surface of the oil) the creo- sote, calculated on the basis of the dry oil, shall give no distillate .below 200°€., not more than 5 per cent below 210°C., not more than 25 per cent below 235°C., and the residue above 355°C. if it exceeds 5 per cent in quantity, shall be soft. The oil shall not contain more than 3 per cent water. 218 METHODS OF COMMUNICATION FOR FOREST PROTECTION 11 — Specifications for Wooden Brackets The articles desired under these specifications consist of oak pole-brackets, fitted to take the standard insulator. .Workmanship. — All workmanship shall be of the best commercial grade. Material. — All brackets shall be made of sound oak, free from knots, checks or cracks, sapwood, worm-holes, and brash wood. The grain of wood on 'all brackets shall be practically parallel to the axis of the threaded portion of the bracket. The grain from the right-angled corner at the end of the bracket shall not run below the bottom thread ,on the opposite face of the bracket. Pole Line Bracket ALLOWABLE VARIATIONS over under dc '/&" Ve" of '/8" '/&" I '/*'' '/4" Specifications 11 Design of Forestry Branch standard wooden bracket All brackets shall be thoroughly seasoned' before being offered for inspection. Dimensions. — The seasoned brackets shall be of the style and dimensions shown in the drawing attached hereto and made part of these specifications. Where maxi- mum and minimum dimensions are shown, the dimensions shall be within the limits specified. Where limits are not shown, the dimensions shall be approximate. Figures upon the drawings shall be followed in preference to scale measurements. ' Thread. — The threaded portion of the bracket shall be as nearly .as possible of a circular cro,ss-seetion. The thread! shall be smooth and of a uniform pitch, ,and such that a standard insulator can be readily screwed on to the bracket until the end of the bracket touches the top of the insulator. When in this position there should be no per- ceptible rocking or play of the insulator on the bracket. Nail holes. — Each bracket ishall h,ave two nail holes as shown,' in the drawing attached hereto. The nail holes shall be well centred and shall be perpendicular to that face of the (bracket which makes an angle with the axis of the (thread. APPENDIX F— SOLDERING 12 — Specifications for Outdoor Protector Mounting-boxes 219 The box used for mounting protector and switch for installation outdoors with the 133'6 — J telephone set shall be onad'e of clear, straight-grained, thoroughly seasoned pine, spruce, or Douglas fir, according to the drawing attached hereto, and made a part of these specifications. Hinges and hasp shall be of brass fastened by brass screws. t_ , Cj ' " : "5 §"~ f rf 0 CD U (D 1 • i \\ j f- in C 0 o (D FEONT • ELEVATION SIDE • ELECTION BfcCK • ELEU&TION Specifications 12 Design of outdoor protector mounting-box Finish. — The box shall be planed smooth inside and' out and treated with a coat American Telephone and Telegraph Co. specifications, as follows: No. 3438 for 40-60 inside and out with two coats of best paint either .grey, dark green, brown, or black. APPENDIX F SOLDERING— METHODS AND MATERIALS Approved Solders. — Approved solders are those made in accordance with the American Telephone and Telegraph Co. specifications, as follows: No. 3438 for 40-60 iolder; No. 3439 for 45-55 solder; No. 3440 for 50-50 solder; No. 3441 for resiii flux wire solder. Approved Fluxes. — Approved fluxes are: (1) plumbers' candles for plumbing and cable work; (2) resin; (3) the stick forms of flux made by the Northern Electric Co., and (4) that known as "Allen's" stick. No other form of flux (such as paste or liquid soldering salts) is to be used. Process. — All parts to be soldered must first be thoroughly cleaned by scraping, filing-, rubbing with emery paper, or some other method. In cleaning galvanized iron, take care not to scrape off all the galvanizing. Heat the joint with the soldering-iron. Do not attempt to apply the solder with the iron. Heating should be just sufficient to melt the resin of resin-core solder or ,of the soldering stick, and the parts should then be thoroughly coated with the flux. 220 METHODS OF COMMUNICATION FOR FOREST PROTECTION Copper rapidly oxidizes when heated in contact with the air, and solder will not adhere to oxidized copper. The purpose of the flux, therefore, is to cover the surface to be soldered while the temperature is still low, and prevent oxidation. Continue the application of the hot iron until the joint has become hot enough to melt the solder which will then flow readily. Do not try to apply resin-core solder with a hot iron and its own flux to a cold surface nor to an oxidized joint. 45-55 Solder. — This solder is to be used for joining split sleeves in cable work, and for large surfaces of metal which are to be soldered. It is also to be used in making joints in old galvanized-iron wire, and similar work. In joining old galvanized wire, clean the ends which are to be soldered with emery cloth and make a Western Union joint; then solder by means of a ladle, using as a flux one of the approved stick forms. Do not use more than is necessary to cause the solder to flow, and apply by rubbing before the first pouring of the solder over the joint. If necessary, apply again after the joint has been heated. A large well-tinned soldering iron may be used, if preferred, instead of pouring the solder over the joint. In such a case the iron must be pressed against the joint so as to warm it just enough to melt the flux when it is held against it. After a coating of this has adhered, apply the hot soldering-iron again and, at the same time, apply the 45-55 wire solder to the joint (do not put the solder on the soldering iron). Wheii the solder melts, having derived its heat from the joint and not from the iron, it will flow readily. A slight tap on the wire will help it to run into the joint well. This solder is furnished in the form of i-in. wire in 10-pound coils, or in bars of 1£ pounds weight, and orders must state in which form it is required. Resin Flux Wire Smolder. — Resin flux wire solder is to be used in solderiiig all wire connections other than galvanized-iron wire, but it may also be used for this purpose in new work, when it is done with a soldering-iroTi. It is also to be used for all work where copper and brass are to be soldered. To use this solder for small work, such as wire joints and terminals, apply to the joint a well-tinned soldering-iron, of suffi- cient size for the work. In soldering terminals, first clean off all old solder and bits of wire by meaiis of a hot iron and then give only one turn of the wire which is to be soldered around the terminals. In larger work, use any convenient means to heat the joint, remembering to get a coat of resin on before enough heat has been applied to the metal to oxidize it, and that the metal to be soldered must be hot enough to melt the solder and burn off the superfluous resin. This solder is furnished i-n 5- and 10-pound coils, and orders must state which size is required. To Solder to Black Iron (1) First thoroughly clean a strip on the pipe about |-in. wide and 2^-in long; ('21) Heat the cleaned place, either with the flame of a gasolene torch or a heated iron, until it is hot enough to melt the soldering-stick; (3) Distribute a coat of flux over this point by rubbing it with a soldering-stick; (4) With a well heated soldering-iron distribute 45-55 solid-wire solder over the cleaned space; (5) Tightly wrap the wire, well cleaned, around the pipe, leaving at least f in. between each turn; (6) Fasten the end of the wire at the end of the coil by twisting it around the wire leading from the pipe; (7) Apply an additional coat of flux; (8) Apply the 45-55 solid-wire solder in the regular manner. Tinning Soldering-iron. — File the iron to the required shape and brightness, and heat until it is only just hot enough to melt the resin of resin-cored solder but not hot enough to change the colour of the bright copper by oxidatioii. When in this condition, coat the part to be tinned with resin and apply heat until the solder melts readily, when it will be found to flow freely on the iron. Do not let the flame come in contact with the tinned part of the iron. APPENDIX G USEFUL TABLES TABLE 1— WEIGHTS OF CEDAR POLES OF VARIOUS LENGTHS AND TOP DIAMETERS Length Top diameter Weight, seasoned Weight, green Length Top diameter Weight, seasoned Weight, green ft. in. pounds pounds ft. in. pounds pounds 20 4 100 130 45 6 900 1,000 20 5 130 170 45 7 1,100 , 250 20 6 190 250 45 8 1,350 ,500 25 4 150 200 50 6 1,150 ,250 25 5 200 260 50 7 1,350 ,450 25 6 250 325 50 8 1,700 1,850 25 7 350 425 55 6 1,350 1.500 30 5 275 350 55 7 1,700 1,875 30 6 350 425 55 8 2,200 2,400 30 7 ' 450 500 30 8 575 630 60 6 1,700 1,800 60 7 2,200 2,350 35 5 375 500 60 8 2,500 2,700 35 6 450 600 35 7 600 750 65 6 2,200 2,450 35 8 850 990 65 7 2,500 2,800 65 8 3,000 3,400 40 6 625 840 40 7 850 1,075 70 6 2,500 2,900 40 8 1,100 1,325 70 7 3,000 3,500 70 8 4,000 4,600 TABLE 2 — NUMBER OF POLES OF DIFFERENT SIZES REQUIRED TO MAKE UP A CARLOAD LOT NUMBER PER LOAD Not less than 175 and up to 225 SINGLE CARS Poles 4 in. in diameter 25 ft. long. 5 25 ' 6 25 ' 7 25 « 6 30 « 7 30 7 35 ' 15-0 lO'O 75 75 60 55 2'00 125 100 100 8-0 75 DOUBLE CARS Poles 7 in. in diameter 40 ft. long. 7 45 55 60 65 NUMBER PER LOAD Not less than 6'0 and up to 75 50 " 65 40 " 55 35 '.' 45 25 " 35 20 " 30 25s and 30s should be loaded on cars taking a minimum of 24,000 pounds; 35s on cars taking a minimum of 30,000 pounds; double loads (40s and longer), on long cars 30,000 pounds each or 60,000 pounds minimum for the double load. All poles up to and including 7 inches, 35 feet, are loaded on single cars. All poles over 35 feet 'in length are loaded on double cars. 221 222 METHODS OF COMMUNICATION FOR FOREST PROTECTION TABLE 3 — COMPARISON OF WIRE GAUGES' The sizes of wires are ordinarily expressed by an arbitrary series of numbers. Unfortunately there are several independent numbering methods, so that it is always necessary to specify the method1 or wire gauge used. The following table gives the numbers and diameters in decimal parts of an inch for the various wire gauges used in this country, Great Britain and the United (States. Number of wire gauge Roebling or Wash- burn and Moens Brown and Sharpe Birmingham or Stubs English legal standard Old English or London inch inch inch inch inch 6-0 0-460 0-464 5-0 0-430 0-432 4-0 0-393 '"6-4600"' 0-454 0-400 0-4540"' 3-0 0-362 0-4096 0-425 0-372 0-4250 2-0 0-331 0-3648 0-380 0-348 0-3800 0 0-307 0-3249 0-340 0-324 0-3400 1 0-283 0-2893 0-300 0-300 0-3000 2 0-263 0-2576 0-284 0-276 0-2840 3 0-244 0-2294 0-259 0-252 0-2590 4 0-225 0-2043 0-238 0-232 0-2380 5 0-207 0-1819 0-220 0-212 0-2200 6 0-192 0-1620 0-203 0-192 0-2030 7 0-177 0-1443 0-180 0-176 0-1800 8 0-162 0-1285 0-165 0-160 0-1650 9 0-148 0-1144 0-148 0-144 0-1480 10 0-135 0-1019 0-134 0-128 0-1340 11 0-120 0-09074 0-120 0-116 0-1200 12 0-105 0-08081 0-109 0-104 0-1090 13 0-092 0-07196 0-095 0-092 0-0950 14 0-080 0-06408 0-083 0-080 0-0830 15 0-072 0-05706 0-072 0-072 0-0720 16 0-063 0-05082 0-065 0-064 0-0650 17 0-054 0-04525 0-058 0-056 0-0580 18 0-047 0-04030 0-049 0-048 0-0490 19 0-041 0-03589 0-042 0-040 0-0400 20 0-035 0-03196 0-035 0-036 0-0350 21 0-032 0-02846 0-032 0-032 0-0315 22 0-028 0-02534 0-028 0-028 0-0295 23 0-025 0-02257 0-025 0-024 0-0270 24 0-023 0-02010 0-022 0-022 0-0250 25 0-020 0-01790 0-020 0-020 0-0230 26 0-018 0-01594 0-018 0-018 0-0205 27 0-017 0-01419 0-016 0-0164 0-01875 28 0-016 0-01264 0-014 0-0148 0-01650 29 0-015 0-01125 0-013 0-0136 0-01550 30 0-014 0-01002 0-012 0-0124 0-01375 31 0-0135 0-00893 0-010 0-0116 0-01225 32 0-0130 0-00795 0-009 0-0108 0-01125 33 0-0110 0-00708 0-008 0-0100 0-01025 34 0-0100 0-00630 0-007 0-0092 0-0095 35 0-0095 0-00561 0-005 0-0084 0-0090 36 0-0090 0-00500 0-004 0-0076 0-0075 37 0-0085 0-00445 0-0068 0-0065 38 0-0080 0-00397 0-0060 0-0057 39 0-0075 0-00353 0-0052 0-0050 40 0-0070 0-00314 0-0048 0-0045 English Legal Standard Gauge. — Also called New British Standard Gauge, or British Imperial .Standard, and very commonly used, in Great Britain and this country. Birmingham Gauge. — Used largely in Great Britain and some of the British Dominions for the measurement of wires of all kinds. In the United States it is applied mostly to the measurement of iron wire. APPENDIX G— USEFUL TABLES 223 Brown & Sharpe Gauge. — The United States standard for wires for electrical purposes. Law of the Brown & Sharpe Gauge. — The diameters of wires on the B. & S. gauge are obtained from the geometric series in which No. 0000=0.4600 inch and No. 36= -005 inch, the nearest fourth significant figure being retained in the areas and diameters so deduced. Let n == gauge number (0000 = - 3; 000 == — 2; 00 = - 1). d == cKameter of wire in inches. Then d = 0-3249 1-128* Sheathing core. — The number (N) of sheathing wires having a diameter (d) which will cover a core having a diameter (-D) is N = D+d TABLE 4— TENSILE STRENGTH OF BARE COPPER WIRE Numbers, B. & S.G. Breaking weight in pounds Numbers, B. & S.G. Breaking weight in pounds Hard-drawn Annealed Hard-drawn Annealed 0000 8,310 6,580 5,226 4,558 3,746 3,127 2,480 1,967 1,559 1,237 980 778 5,650 4,480 3,553 2,818 2,234 1,772 1,405 1,114 883 700 555 440 9 617 489 388 307 244 193 153 133 97 77 61 48 349 277 219 174 138 109 87 69 55 43 34 27 000 00 0 10 11 12 - 13. 1 2 , 3 4 14 15 16 17... 18 19 20 5 6 7 8 The strength of soft copper wire varies from 32,000 to 36,000 pounds per square inch, and of hard copper wire from 45,000 to 68,000 pound's per square inch, accord- ing to the degree of hardness. The above table is calculated for 34,000 pounds for soft wire and 60,000 pounds for hard wire, except for some of the larger sizes, where the breaking weight per square inch is taken at 50,000 pounds for 0000, 000, and 00, 55,000 for 0, and 57,000 pounds for 1. TABLE 5— PROPERTIES OF HARD-DRAWN COPPER TELEPHONE AND TELEGRAPH WIRE Furnished Approximate size Size B. & S.G. Resistance Breaking Weight in coils as E. B. B. iron wire per mile strength per mile follows equal to copper in conductivity. Ohms Pounds Pounds Miles 9... 4-30 625 209 1-0 2 10 5-40 525 166 1-2 3 11 6-90 420 131 0-52 4 12 8-70 330 104 0-65 6 Iron-wire gauge. 13 10-90 270 83 1-20 6* 14 13-70 213 66 1-50 8 (B.W.G.) 15 17-40 170 52 2-00 9 16 22-10 130 41 1-20 10 224 METHODS OF COMMUNICATION FOR FOREST PROTECTION In handling- this wire the greatest care should be observed1 to avoid kinks, bends, scratches, or cuts. Joints should be made only with copper splicing sleeves and connectors. On account of its conductivity being about five times that of E. B.B. iron wire, and its breaking strength over three times its weight per mile, copper may be used of which the section is smaller and the weight less than an equivalent iron wire, allowing a greater number of ^ires to be strung on the poles. Besides this advantage, the reduction of section materially decreases the elec- tro-static capacity, while its non-magnetic character lessens the self-induction of the line, both of which features tend to increase the possible speed of signalling in tele- graphing, and to give greater clearness of enunciation over telephone lines, especially those of great length. TABLE 6— PROPERTIES OF BIMETALLIC WIRE 1 Numbers, B. & S.G. Diam- eters in mils Weights per mile in pounds Breaking weight in pounds Numbers, B. & S. G. Diam- eters in mils Weights per mile in pounds Breaking weight in pounds 0000... 000 460 410 3,200 2 537 10,500 8 600 7... 8 144 128 314 246 1 210 1 020 00 365 2,022 7,000 9 114 203 850 0 325 1,620 5,700 10 102 157 660 1 2 289 258 1,264 1 003 4,600 3,800 11 12 91 81 127 100 520 410 3 229 797 3 200 14 64 63 260 4... 5 204 182 629 490 2,600 1,790 16 18 51 40 40 25 160 100 6 162 398 1,500 Adapted from " Wire in Electrical Construction " by John A. Roebling's Sons Co. This wire consists of a steel centre with a cover of copper. Its conductivity is about 65 per cent of that of pure copper. The percentage of copper and steel may vary a trifle, hence the strength and weight must be approximate. TABLE 7— PROPERTIES OF GALVANIZED TELEPHONE AND TELEGRAPH WIRE.1 Approximate Approximate breaking Resistance per mile (Interna- Diameter Area weight in pounds strain in pounds tional ohms)at 68°F. or 20° Size in in C. B\\T (~~* *1 rl • i . W . U". mils — d circu.i» CO ^ CO CO OO 2 ^ ^ (M pq .2 a *s-s ^ . .: § • i || si i ^ I ^ °. M ^H" JH 'S S g C I-H O O t-f o i!-s 3 o i) _ 1 H * ^ S «i t J INDEX Acetylene lamps, 182 Adams portable telephone, 39, 108, 1.10, 130, 11312, 152 Adjustment of heliograph, 174 of ringers, Ii50 Alignment of tree lines, 6*8 Alphabet, International 'Morse, 176 Alternative routes, 2'6 American Army heliograph, 163 Ampere, definition of, 119' Ardois lanterns, 1'5 Armature, generator, 128 Attachment, split tree insulator, 70 Auger, post-hole, 38> Bars, digging and tamping, 38 Batteries, dry, types of, 39, 86, 108, 121, ,125 inspection of, 149' installation of, 85 removal of, 818 renewal of, 87 testing of, 88 Bell, Professor Alexander Graham, l'2'l Bells, extension, altering tones of, lOli extension, types of, 39, HOI used as signals, 15 Belts, linemen's, 37 Books, reference, I'S'S1 Braces, pole, 54 Bracing of poles, 54 Brackets, wood, 37, 50, 52, 70, 74 wood, attachment of, 52 wood, position of, 52 wood, specifications for, 2)18 Branch lines, 8'2 Bridging-bell system of telephone connection, 13(8. British Army heliograph, 162 Brush method of treating poles, 48 Buffalo grips, 38, 64, 158 Butt-rot in poles, 142, 143. Buzzer telegraphy, 1)6, 1H31 Cables, lead-encased, properties of, 225 Calls, telephone, list of, 141 Camp management, 3, T2 Capacity, definition of, 131 Carbolineum, 48 Cell, inert, 184 voltaic. 127 voltaic, definition of, 118 Cells, closed circuit, 125 open circuit, 1125 Circuit, definition of, 118 grounded, 28, 32, 60, 90 grounded, connection to metallic, 104, 106 grounded, definition of, '32 light, 32 metallic, 28, 32, 60, 68, 90 metallic, connection to grounded, 104, 136 metallic, definition of, 32 phantom, HO'3, 13'7 power, 32 Clamp, Blackburn ground, 91 Fahnestock test, 82, 14*3 Clamps, ground, types of, 41 Climbers, linemen's, 37 Code, Alphabetical Square, 178 American Morse, 175 International Morse, 115, I'M, 17'5, 193 Myer, 177 ringing, 128, 140 signals, 22 Codes, heliograph, 17'5 message, Ii9'4 Coil, induction, definition of, 119 induction, use of in telephone, 125 telephone induction, inspection of, 1'49 Coils, lavite, 9'8, 159 protection of, 9'8 repeating, 40, 9'8, 10<3\, Ifl5 use of, 9'8 Commissary, 3, '11 Condenser, definition of, 12'0 types of, 4.0 use of, 85, 9i6, 13'1, 1!3'2 use of, in vibratory signalling, 9'6, H32 Conductor, definition of, 118 Connectors, emergency, 11)5 Construction materials, free grant of, 34 Conventional signals, International Morse, 176 Cooking outfit, list of, W9 Co-operative telephone lines, 3'3 Cord, receiver, il-2'3, 149" receiver, inspection of, 149 Costs, telephone construction, in different types, 28, 201 telephone construction, elements of, 201 Cradle, Mobley wire, 4'© Creosote, specifications for, 217 use of, 48 Crew, emergency line construction, 75. 7'6 telephone construction, 46, H9'6 Crews, equipment of, 46 Crossing divides, 73 meadows and parks, 7'3 rivers and canyons, 7'3 Crossings, extra long, 78 foreign, 7'8' high-tension transmission lines, 78 Railway Board .Regulations governing, 203 railway right of way, 78 road, 78 submarine, 80 Cross-talk, 3.2, 62, 142 elimination of, 15« Crossties, 71, 8-3 Current, alternating, 127, 128 alternating, definition of, 120 difect, definition of, 12/9 Dead-ending, 71, 82, 8*3 Detection of forest fires, 3, 5 Detonations, use of, as signals, 15 " Dont's " in telephone construction, 1'57 in telephone installation, 158 in telephone maintenance, 159 in telephone operation, 15>8 Edison, Thomas 'A., 125 Electric lamps, use of, in signalling, Ii8'3 Electro-motive force, definition of, 1'18 Emergency communication equipment. us.e, of. 227 228 METHODS OF COMMUNICATION FOR FOHKtiT PRO1 'I-:('TIO.\ Emergency lines, connecting to permanent. 7'5 maintenance of, 7>6> pole setting on, 76 taking up wire on, 76 use of, 74 Emergency telephone kits, types of, 39' telephone kits, use of, 10-8, 1I1'4 Equipment of construction crews, 4'6 standard list of, >36 Exchanges, private, 8>2 External telephone systems, 24 Fire boss, 1>8 'Fires, forest, detection of, 5 forest, prevention of, 3, 4 forest, suppression of, 7 Fischer high-power lamp, 184 Flags, range of, in signalling, Ii8(6' speed of, in signalling, li&T use of in forest protection, 22, 1'87 Flux, 40, 219 Forest protection force, functions of, 3 Forest iService heliograph, I'6i5 Free service on Forestry Branch lines, 35 Frequency, definition of, 120 Fuses, types of, 39 use of, 88, H35 Galvanizing, specifications for, 209 Gauges, wire, names of, IV wire, comparison of, 222 Generator, electro-magnetic, 120 oiling of, Ii50 telephone magneto, 121, 127 telephone magneto, repairs of, 145, 147 Ground rods, portable, 41 portable types of, 41 Grounds,' 3'2, 9'0 multiple, '9-2 precautions in locating, 91 temporary, 116 Guy rods, 38 Guys, anchor, 55 pole, 54 rock, 57 tree, 56 Hammers, claw, 4.1 Hand set, Adams, 39, liO«, 1-10, 11130, 1,32, 1152 Haven clamps, 38 Haze, effect on range of heliograph, 175 Heliograph, 1160 adjustment of, 1174 American Army, 1160, H6<3, 173 British Army, 1,6-0, 162, 173' Forest Service, 16>0 Godwin, 160, 1(6*5, H&9 mirrors, I1 6' 9 parts of, 1'6'9 range of, 1'61 screens, 170 sighting-rods, l'7'O speed of, 161 stations, 21, 160, 165 tripods, 170 use of in forest protection, 21, l'6'O use of at lookout stations, 165 use of on patrol, 169 Heliographs on towers, 16'8 Heliographing by artificial light, 181 by moonlight, 1-81 with one mirror, 1711 with two mirrors, 172 High-tension lines, interference from, 42, 60, 62, 7'8, 104 protection from, 89, 94, 1134 Hitch, barrel, use of, 76 Holes for telephone poles, digging of, 50 Howlers, 40, 96, 132 use of in vibratory signalling, 9'6 Induction, electro-magnetic, definition of, 119 electro-static, definition of, 120 Insulator, definition of, 1X8 Insulators, glass, specifications for, 2H31 •glass, types of, 37, 52 glass, use of, 27, 74 split tree, attachment of 70, 7|3 split tree, specifications for,. 214 split tree, types of, 37 split tree, use of, 29, 30, 42, 44 strain, 41, 71 Internal telephone systems, 25, 36 Joints, emergency wire, 7'6 insulated wire, 93. Western Union, 65 Kitchen equipment, list of, 19'S Knives, electricians', 40' Lanterns, acetylene, for signalling, 182 electric, for signalling, Is8i3, 184 Fischer high-power, 184 signalling, 182 Lightning arresters, types of, S'91 arresters, use of 88, I'S'S' danger of, in construction, 60 Linemen, 29 "Listening in," Ii31, 13'2 Location of telephone lines, factors influencing, 42 Lookout men, permanent, in forest protection, 17, 18 stations, 7, 21, 2*6, 36, 7(3, H6'5, I<8i5, 18'7 station telephones, 94 stations, heliograph at, 16'5 Magnet, definition of, 118 Magnets, use of, in generators, 1/28' use of, in ringers, ll>2!9 Magneto telephone, description of, 117 Materials, emergency line, 74 line, 59, 6'9 standard, list of, 36 Mclntyre sleeves, 38, 6(5 Message codes, 194 Microphone, carbon, 123 Mil, definition of, 121 Mobley wire-cradle, 43 46 Monkey-wrench, 41 Mounting-box, protector, specifications for, 219 Nails, 37 milonite, 40, 94 Numerals, International Morse, 176 Ohm, definition of, 119 Ohm's Law, 111-9' Open-tank treatment of poles, 48 Operators, heliograph, training of, 180 Pack-frames, Klondike, 45, 46 Mobley, 4i3, 4'6 Packmaster, 10, 18, 19 Party lines, definition of, 1137 Patrol, railway speeder, portable telephone for, 1-09 Patrolmen in forest protection, 18, 21, 2'5. Permanent forces, direction of, 9 Pigeons, carrier, 14 Pike-poles, 38 Pipes, grounding on, 91 Plans, fire, 9 telephone system, 2'3, 25 Plates, ground, types of 41, 91 Pliers, linemen's, 3'7, 40 I^DEX 229 Pole lines, definition of, 27 Poles, cedar, specifications for, 215 dimensions of, 47 lasting qualities of various species of, 47 number per carload, 221 preservative treatment of, 47 seasoning of, 47 self-supporting, 57 setting of, 52 shortened, re-setting of, 14'5 weights of various lengths and tops, 221. Pole-steps, 41, 52 •Preservative treatment of poles, 47 Prevention of forest fires, 3, 4 Private telephone lines, 3<3 Protection standards in relation to telephone lines, 35 Protectors, in fully exposed stations, 89 in partially exposed stations, 89 location of, 89 repair of, 147 telephone, types of, 38 'telephone, types of, 39 Provisions, list of, l'&8 Public roads, use of for telephone lines, 44 Punctuation, International Morse, 1!7'6 Quartermaster, 11, T2, 1>8 Railways, crossing of, 78 Rake, in pole-setting, 50, 52 Receiver, head, 3$ telephone, 121, I'M, 152 telephone, repairs of, 146, 149 Reconnaissance in fire protection, 3, 11 Reel, emergency wire, 38, 75 pay-out, 318, 60 Relay stations, 26* Repeating coils, 40 Reserves, in forest protection forces, 9 Resistance, definition of, 119 Right of way, clearing of, 44 securing of, 42 Ringers, telephone, 1121, 128 telephone, Ohm resistance of, 2*3, ,1129, 139' telephone, repairs of, 148, 15'Q, 1'5>2 Roads, crossing of, 7& Rods, ground., 41, 91 ground, inspection of, 1'47 ground, portable, 11'6 lightning, 39, 52 'Roof ridge of poles, position of, 53 Rules, operating, 140 •Sag allowance, 2.9', 62, 70 distribution of, on pole lines, 6'3 Screw-drivers, 40 •Scouts and scouting in forest protection, 3, 18, 19 Semaphore, fixed, 191 signalling with flags, 188, 19-1 signalling with fixed,, 191 signals, 14 Series system of telephone connection, US'? Shovels, types of, 3>8 Signalling, buzzer or vibratory, 1113 Signals, audible, 14, H5, 22 chronosemic, 1'4 code, 14 colour, 15 danger, 22, 196 electro-telegraphic, 15 flash, 15 shape, 15 shot, 1.916 visual, 14 whistle, 19)6 .Smoke, effect on range of heliograph, 175 ".Smoke chaser," 7, 9, 1'S1, 19, 25 ,Solder, 40 Soldering copper, 40 methods and materials-, 219 Spacing of poles, 50 Splicing clamps, 37 wire, 65 Spools, emergency wire, 74, 75, 7'6 emergency wire, specification for, 217 iSpoons, digging, 38 Standards, D. F. B. construction, 60 .Staples, Blake insulated, 40 Static electricity, 15'6 Stations, heliograph, selection of, 173 signalling, 173, 18'8 Strand, galvanized steel, 41, 71 Strategy, fire suppression, 3, 12 Stubs, as pole reinforcements, 143 Submarine telephone lines, 8'0 Supervision, fire-fighting, 3, 8 . Supervisor, forest, 18, 19, 2<3, 3>4, ,3'5 Supplies, pole-line, 19'7 station, Ii9'.7 tree-line, 19(7 Supports, in forest protection forces, 9 .Suppression, fire, 3, 7 forces, maintenance and direction of, 9 forces, mobilization of, 9 staff officers, 10 Survey of route for telephone line, 42 Surveys, forest, use of signals on, 187 Switchboards, 1011, 135 Switches, 1.31, 13(5, 142 repair of, 147 .Switch-hook, 121, 130, 107. 108 portable, Adams, 3>9, 10'8, 110, 130, 132, 152 portable, Forest Service Special, 39, 108, 1114, 130, 1152 simultaneous operation with telegraph, 106 wall set, 38, 85 wireless, 14, 16 Tension, definition of, 120 Tentage for telephone crew, 198 Test sets, 10'7 stations, 2:6, 142 Ties, regular, 6*3 " figure 8," '6>3, 64, 713, 78 Timber conditions, influence on telephone con- struction of, 301 Tools, emergency line, 74, 198 linemen's, 37, 46 line-stringing, 3'S, 46, 197 pole-setters, 38, 4'6, 19'7 Torch, soldering, 40 Tree lines contrasted with pole lines, 28 cost of, 2i8, 2'01 definition of, 27 development of methods, 29 Transmitter, telephone, 121. 123 telephone, inspection of, 147 White (qr solid back), 123 230 METHODS OF COMMUNICATION FOR FOREST PROTECTION Transportation in forest protection, 1,0 Transposition, 32, 62, 6« Trimmers, tree, 41 Tripods, as line supports, 57 heliograph, 1'69, -170 Trouble, telephone, guide to clearing, 115*3 Trumpet blasts, used as signals, 15 Tubes, porcelain, 40, 92 Tying-in wire, 68 Vibratory signalling, 9<6, 113 Volt, definition of, 118 Voltmeter test-stations, 142 Whistle blasts, used as signals, 15 Wigwag codes, Ifld signalling with flags, 189 signals, 14 Wire, bimetallic, properties of, 224. copper, 28, 3'3, 317, 60, '6)1, 81, 8'3, 92 copper, properties of, 223' copper, specifications for, 2.11 copper, tensile strength of, 223 D. F. B. standard, properties of, 226 emergency, 27, 3'7, 74 emergency, specifications for, 211. galvanized-iron, 23, 28, 33, 36, 59, 69 galvanized-iron properties of, 224 galvanized-iron, specifications for, 210 galvanized steel, properties of, 225 ground, 9'3 man-packing of, 46 rubber-covered, specifications for, 212 stringing of, 2'9, 60, 7^0 Wiring, inside building, 9'3 outside building, 92 THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW AN INITIAL FINE OF 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO SO CENTS ON THE FOURTH DAY AND TO $1.OO ON THE SEVENTH DAY OVERDUE. SiP V 1941 M LD 21-100m-7,'40 (6936s) 982320 THE UNIVERSITY OF CALIFORNIA LIBRARY