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 4 4 (California 
 
THE FUELS 
 OF THE HOUSEHOLD 
 
 Their Origin 
 Composition and Uses 
 
 By MARIAN WHITE 
 
 TEACHER OF DOMESTIC SCIENCE 
 
 McKlNLEY MANUAL TRAINING SCHOOL 
 
 WASHINGTON, D. C. 
 
 WHITCOMB & BARROWS 
 
 BOSTON 1909 
 
\N 5 
 
 COPYRIGHT 1909 BY 
 MARIAN WHITE 
 
 THOMAS TODD CO. 
 
 PRINTERS 
 14 BEACON ST., BOSTON, MASS. 
 
TO MY FATHER 
 
 190898 
 
PREFATORY NOTE 
 
 TN writing this essay I have assumed an audience of 
 * young housekeepers and those who are to become 
 such. I have sought the best information on the subject 
 which the abundant professional and bibliographical re- 
 sources of the National Capitol afford, but I have thought 
 it best to use a style of direct statement rather than one 
 embracing complex statistical forms. 
 
 I am especially indebted to my father, Dr. Charles A. 
 White, whose abundant published writings on geological 
 and botanical subjects are well known. He has not only 
 placed his large accumulation of manuscripts at my dis- 
 posal, but I have constantly had the benefit of his counsel 
 and of his personal recollections of many of the con- 
 ditions and events of which I have written. M. w. 
 
CONTENTS 
 
 PAGE 
 
 I. INTRODUCTION . i 
 
 II. COMPOSITION OF FUELS 5 
 
 III. COMBUSTION, IGNITION, AND INCANDESCENCE . . 10 
 
 IV. THE SOLID FUELS: MINERAL COAL, COKE, AND PEAT, 26 
 V. THE SOLID FUELS: WOOD AND CHARCOAL .* -37 
 
 VI. THE SEMI-SOLID FUELS 51 
 
 VII. THE LIQUID FUELS 60 
 
 VIII. GASEOUS FUELS . . 73 
 
 IX. ECONOMY OF FUELS 81 
 
 X. ELECTRICITY 93 
 
 INDEX 96 
 
 vii 
 
'' V & S | T Y 
 
 CHAPTER I 
 INTRODUCTION 
 
 THAT the natural resources of light and heat are 
 universal is shown by the energy and diffusion 
 of the sun's rays throughout the solar system, by the 
 intensity of heat in active volcanoes, and by the fierce- 
 ness of lightning flashes when storms prevail. So small, 
 however, is the draft that man has hitherto been able 
 to make upon those great natural resources for economic 
 uses that nearly all his supplies for those uses are obtained 
 by artificial means. 
 
 To a comparatively small extent the sun's rays have 
 been utilized, and under specially favorable conditions 
 light is now abundantly produced by the artificial con- 
 trol of electric currents, and heat for domestic and other 
 economic uses is largely obtained by the same means. 
 The fact still remains that, with exceptions to be men- 
 tioned on following pages, the light and heat which are 
 practically used in the household and industrial arts are 
 artificially produced from substances called fuels, by 
 chemical processes which are ordinarily called combustion 
 and incandescence, respectively. 
 
 The same kinds of fuels are used, or are usable, in 
 the household that are used in the industrial arts ; and 
 although much the greater part of the fuels which are 
 now utilized by man are consumed in the world's great 
 activities, success in housekeeping is quite as dependent 
 
 i 
 
2 HOUSEHOLD FUELS 
 
 on the skillful selection and management of fuels as it 
 is in the case of great industrial enterprises. 
 
 The three principal objects for which our household 
 fuels are used are the warming of our dwellings, the 
 lighting of them, and the cooking of our food. Although 
 it is true that light may be produced with little or no 
 accompanying heat, and that heat may be produced with 
 little or no light, all the fuels which are now used for 
 lighting may be, and in many cases are, used for heating. 
 Therefore the term "fuel" is employed to designate all 
 those combustible substances which are used in our 
 households and in the industrial arts to produce either 
 light or heat, or both. The fuel substances which are 
 to be considered in the following chapters are such as 
 are commonly used in the household, and all of them 
 are obtainable in the fuel markets or from special 
 dealers. 
 
 For convenience of reference on following pages, 
 household fuels are divided into solid, semi-solid, liquid, 
 and gaseous fuels. The solid fuels are mineral coals 
 and coke, wood and charcoal, and peat. The semi-solid 
 fuels are wax, fats, resin, stearin, palmitin, spermaceti, 
 and paraffin. The liquid fuels are the oils and alcohols. 
 The gaseous fuels are the natural and artificial gases 
 which are readily combustible, but which are not con- 
 densible to a liquid condition except at extremely low 
 temperatures, too low for practical consideration. Fuels 
 are also in part grouped with reference to their origin ; 
 as some are of animal origin, some of vegetable origin, 
 and some are derived directly from the earth. The last 
 mentioned fuels are appropriately called mineral fuels, 
 
HOUSEHOLD FUELS 3 
 
 although some, if not all of them, are primarily of 
 vegetable origin. 
 
 In discussing these fuels and their uses on following 
 pages, the mental scene of all the processes and utilities 
 which are mentioned is the household. The households 
 of our country are so distinctively American that the 
 subject of this essay is naturally devoted to that type. 
 The historical range of that type is short, because the 
 political history in connection with which it was devel- 
 oped is short compared with that of other countries. 
 And yet, eventful as that short political history has been, 
 the household affairs which have pertained to the use of 
 fuels have been quite as eventful. 
 
 For example, there are aged persons now living who 
 were born and reared, not upon the westward moving 
 frontier, but among the settled population of the Eastern 
 states, who, during their childhood and early youth, 
 never ate any food that was not cooked either at the 
 open kitchen fire or in the adjacent brick oven. No cast- 
 iron ranges, nor even the commonest cook stoves, had 
 then come into use. Neglected fires were rekindled by 
 means of the flint and steel, or, if the tinder box was 
 out of order, one of the children was sent to a neighbor's 
 house to " borrow fire." A half-burnt brand was taken 
 from the kitchen hearth and swung over the head of the 
 running child to keep it burning. Friction matches were 
 not then invented. The usual household light was that 
 of rude tallow candles, and the best light then available 
 for household use was obtained from whale oil. 
 
 This oil deserves special mention because the demand 
 was then so great that ships sailed every sea to obtain 
 
4 HOUSEHOLD FUELS 
 
 it. Mineral oil, except in quantities too small for prac- 
 tical use, was not then known to exist in our country. 
 When that oil was discovered by deep boring, it came in 
 such quantity, and its refined product, kerosene, came 
 so suddenly and abundantly into use, that the whaling 
 business was destroyed, and the ships returned to port 
 empty and rotted at their docks. Illuminating gas from 
 coal had hardly passed its experimental stage, even in 
 the larger cities, and the most prophetic mind among the 
 people never conceived of lights so brilliant and service- 
 able as those with which our households and public 
 buildings are now furnished. Churches and public halls 
 were not warmed, and in bitter winter weather the whole 
 family gathered around the roaring wood fire upon the 
 great kitchen hearth. No system of general housewarm- 
 ing was then known, and mineral coal was seldom seen 
 except upon the blacksmith's forge. That such revolu- 
 tions as these could have occurred with relation to the 
 domestic customs of a progressive people within the 
 memory of an individual is marvelous but true, and 
 the half has not been told. 
 
CHAPTER II 
 COMPOSITION OF FUELS 
 
 T)ECAUSE the foregoing classification, or manner of 
 -*-* grouping, of the fuels is followed in the subsequent 
 chapters, it will be necessary to remember them to have 
 a clear understanding of the statements therein made. 
 It is also quite necessary for one who desires to know 
 fuels to become familiar with the elementary facts per- 
 taining to their composition and their manner of com- 
 bustion to produce heat and light. It is for the purpose 
 of briefly summarizing those facts that this and the next 
 following chapters are introduced. 
 
 The Chemical Elements. Not only the earth and 
 all that pertains to it, including its solid mass as a planet, 
 but its waters and all that they contain, its atmosphere 
 and all that pervades it, and all the animal and vegetable 
 forms which dwell or grow upon it, consist of various 
 kinds of matter which are called elements and com- 
 pounds of elements. Those chemical elements have never 
 been divided into other substances, as the compounds 
 have been, and they are generally regarded as incapable 
 of such division. Their number at present known is 
 above seventy. In density and other properties they vary 
 from ponderous metals, as iron, on the one hand, to in- 
 visible gases, some of which are lighter than air, on the 
 other. Very few elements are found free in nature, but 
 are usually combined with other elements. Every such 
 
 5 
 
 ' Of THt 
 
 UNIVERSITY 
 
HOUSEHOLD FUELS 
 
 combination produces a substance which is quite unlike 
 any of the elements of wh^ch it is composed. 
 
 Chemical Reaction. The inclination which the 
 elements have to unite to form compounds whenever 
 they are brought into intimate contact under such con- 
 ditions as solution and heat varies so greatly that an 
 element will often leave its associate in a compound and 
 unite with another element. The two freed elements 
 either unite to form another compound, or, in passing 
 off, each unites with other elements. This exchange of 
 association is called chemical reaction, and all known sub- 
 stances are liable to be affected by such reaction. What- 
 ever may be the result of such questions as have lately 
 been raised as to the destructibility or transmutability of 
 elements, such possibilities need not be considered with 
 relation to the elements concerned in fuel combustion. 
 We see and handle those elements in their visible and 
 tangible condition, and, although they become invisible 
 and intangible when their combustion has occurred, we 
 demonstrate that they still exist when we account for the 
 products of combustion. 
 
 Sometimes chemical reaction is slow, as in the rusting 
 of iron and in what is ordinarily called decay of animal 
 and vegetable substances. Sometimes it is very rapid, as 
 in the burning of fuels, especially the fierce flames of 
 liquid and gaseous fuels. Sometimes it is explosive, 
 as is seen in the so-called fire tests of the mineral oils, 
 and by the disastrous results of the careless handling of 
 gasoline. 
 
 The Fuel Elements. There are only a few of the 
 large number of the chemical elements with which we 
 
HOUSEHOLD FUELS 7 
 
 shall have anything to do in the study of household fuels. 
 Indeed, there are only three of them which take really 
 an active part in the combustion of fuels, namely, carbon, 
 hydrogen, and oxygen ; but it will be necessary to men- 
 tion a few others as accessories to combustion and to 
 ignition, or the kindling of fires. Each of the elements 
 generally assumes a very different condition in every 
 combination which it makes with another element, but 
 such trans formations need be mentioned only for those 
 which are immediately concerned in fuel combustion. 
 For example, oxygen, which is so abundant that it is 
 estimated to constitute nearly one-half of the bulk of the 
 earth, exists in a great variety of conditions. It enters 
 largely into the composition of minerals and into the 
 solid part of vegetable matter, where it is necessarily 
 solid. It is a large constituent of water, where it is of 
 course liquid. It constitutes a large part of the atmos- 
 phere, where it is closely associated with, but not chem- 
 ically united to, nitrogen. In that association it is 
 necessarily gaseous, as it always is in its pure state. 
 
 The diamond is the purest form of carbon known, 
 and in that condition it is one of the hardest of known 
 substances. Charcoal, coke, and anthracite, although 
 widely different from the diamond, are nearly pure forms 
 of carbon. All the other solid fuels, as well as the semi- 
 solid fuels, are largely composed of carbon, and in these 
 fuels it exists in a more or less solid condition. Carbon 
 also forms a component part of all alcohols and oils, in 
 both of which kinds of fuel it is necessarily liquid. It 
 is an essential component of all the gaseous fuels, and 
 in them it is necessarily gaseous. 
 
HOUSEHOLD FUELS 
 
 Hydrogen in a free state is an inflammable gas, which 
 burns with a bluish flame, and is the lightest substance 
 known. In the gaseous fuels it combines with carbon 
 and still retains its gaseous condition. In combination 
 with oxygen, hydrogen generally assumes the liquid 
 condition, that combination forming water. In all the 
 other liquid fuels of which hydrogen forms a part, it is 
 necessarily liquid. Hydrogen enters into the composition 
 of all the solid and semi-solid fuels, with the excep- 
 tion of pure anthracite, coke, and charcoal. In these 
 fuels it is necessarily in a correspondingly solid condition. 
 
 Accessory Fuel Elements. It is desirable to men- 
 tion a few other elements which enable us to get a more 
 complete view of the nature of combustion. Nitrogen 
 should be specially mentioned in this connection, although 
 it is wholly inert in the process of fuel combustion. It 
 is very abundant everywhere, associated with oxygen 
 in the atmosphere, and when freed from that association 
 by fire it accompanies the products of combustion and 
 goes unchanged to take its former place in the atmos- 
 phere. In its pure state nitrogen is a colorless gas, but 
 like other gaseous elements it becomes a solid by some 
 of the combinations which it makes with .other elements. 
 Such an example is seen in the well-known saltpeter, or 
 nitrate of potash, which is mentioned among the kindling 
 materials in a following chapter because it is combustible, 
 although not a fuel. 
 
 It is proper to mention here that within a few years 
 three other gaseous elements have been discovered in 
 the atmosphere. They are rare, or little known, but in 
 fuel combustion they seem to hold the same position with 
 
HOUSEHOLD FUELS 9 
 
 relation to the fuel elements that nitrogen does, that is, 
 entire inertness. The names which have been given to 
 these elements are argon, helium, and neon, respectively. 
 The Importance of Carbon and Hydrogen. In 
 the next chapter statements are made concerning the 
 process of combustion of the different kinds of fuel which 
 show the great importance of oxygen in all those proc- 
 esses ; and yet they show that oxygen is not itself a fuel. 
 The only true fuel elements arc hydrogen and carbon; 
 but there can be no combustion of those elements with- 
 out oxygen. Being indispensable, it is fortunate that 
 oxygen is always and everywhere at hand, free of expense 
 and requiring no labor for its preparation and storage. 
 On the other hand, hydrogen and carbon must be obtained 
 by great labor and at great expense. 
 
CHAPTER III 
 
 COMBUSTION, IGNITION AND 
 INCANDESCENCE 
 
 OXIDATION. Oxygen, which is ever present in 
 the atmosphere, has a constant tendency to unite 
 chemically with most of the other elements. Consequently 
 it readily leaves its associate, nitrogen, to unite with 
 them, that being the act of oxidation which is to be so 
 often mentioned in the following remarks. Fuels ex- 
 posed to the air are all attacked by oxygen and undergo 
 a very slow process of oxidation at ordinary tempera- 
 tures, and without fire. This open-air oxidation is hardly 
 perceptible, even after long exposure, in the case of the 
 hardest of the solid fuels, but it always exists, and differs 
 from burning by fire only in the length of time in which 
 it is accomplished. Even the amount of heat which is 
 given off in the process is the same in both cases, because, 
 as is well known to chemists, the amount of heat which 
 is given off by oxidation is always in proportion to the 
 extent of that process. In the case of open-air oxidation 
 of fuels, heat is given off too slowly to be perceptible 
 to the senses, but so rapidly in the case of their ignition 
 that combustion results. 
 
 Combustion. If fuels are placed in suitable recep- 
 tacles and fire is applied to them, they also take fire and 
 are more or less quickly consumed. This process is com- 
 bustion, the well-known burning of fuel, in which, instead 
 
 10 
 
HOUSEHOLD FUELS II 
 
 of the exceedingly slow rate of open-air oxidation, there 
 is a violent and rapid oxidation which quickly converts 
 the fuel into what are called the products of combustion. 
 
 With the exception of anthracite, coke, and charcoal, 
 all solid fuels contain enough hydrogen to give off more 
 or less flame. When either of those three fuels burn, 
 there is only carbon combustion, and the fire consists of 
 a bed of embers. Hydrogen is often called the greedy 
 element because it will unite with oxygen more readily 
 than any of the others ; so when hydrogen is contained 
 in any of the solid fuels it is more readily ignited than 
 is the carbon. After the burning of the hydrogen has 
 ceased, the carbon combustion proceeds alone, forming, 
 as in the other case, a bed of embers which, when ex- 
 hausted, leave only the ashes. The manner of combustion 
 of the flame fuels will be discussed further on. 
 
 Products of Combustion. The products of com- 
 bustion are, properly speaking, only those invisible gases 
 and vapors which pass off in the upward current that heat 
 causes to rise from the burning fuel. That term does 
 not include smoke, soot, or ashes, but they ought to be 
 briefly referred to in this connection. 
 
 Smoke consists largely of finely divided carbon which 
 has been partially oxidized in the fire but not consumed, 
 and, in company with more or less watery vapor, escapes 
 from the fire by the upward draft. Smoke represents 
 wasted fuel ; the denser the smoke the more fuel is wasted. 
 The very light-colored smoke which one often sees 
 escaping from chimneys consists largely of watery vapor. 
 
 In the burning of wood and some of the softer coals, 
 a part of the oily compounds which are included with 
 
12 HOUSEHOLD FUELS 
 
 the hydrocarbons are volatilized, escape full oxidation, 
 combine with fine, escaping particles of free carbon, 
 adhere to the inner walls of the chimney flue, and con- 
 stitute chimney soot. The soot from wood fires is also 
 impregnated with creosote. 
 
 Wood ashes consist of certain mineral substances 
 which the growing tree takes from the earth dissolved 
 in its food-sap, together with such accidental impurities 
 as become embodied in, or mingled with, them during the 
 growth of the tree, or afterward. Coal and peat ashes 
 often contain mineral materials which have accumulated 
 while those fuels were forming. Certain of the mineral 
 substances which are contained in the coal ashes are often 
 fused by the fire into lumps which become hard on cool- 
 ing, and are commonly called clinkers. Excess of ashes, 
 and especially of clinkers, which sometimes occurs in coal 
 ashes, retards combustion by obstructing the under draft. 
 Hard wood ashes contain much potash, which was for- 
 merly the chief reliance for making the family soap. 
 Ashes of the pines and of the other conifers contain very 
 little potash, and coal ashes contain no appreciable amount 
 of it. 
 
 The chief products of combustion proper are carbon 
 dioxide and carbon monoxide, and, when the fuel con- 
 tains hydrogen, water is produced as steam. It should 
 be remembered that steam is invisible. What we gener- 
 ally call steam is really watery vapor, or steam in the 
 process of condensation. The two products first named 
 originate in fuel combustion as invisible gaseous com- 
 pounds that are formed by the chemical union of oxygen 
 from the air and the carbon of the fuel. When two 
 
HOUSEHOLD FUELS 13 
 
 parts of oxygen unite with one part of carbon, the gas, 
 carbon dioxide, is formed. This gas is heavier than air 
 at ordinary temperatures, but, heated by the fire in which 
 it originates, its relative weight is decreased and it rapidly 
 rises with the upward current, which also 'mechanically 
 assists it to rise. Carbon dioxide is not only incom- 
 bustible, but it will extinguish fire as quickly as will water 
 if allowed to cover it. The union of one part of carbon 
 with one part of oxygen produces the gas, carbon mo- 
 noxide, which is often seen burning with a slight bluish 
 flame over smoldering fires of both coal and wood. It 
 is a product of incomplete combustion, while carbon diox- 
 ide is a product of complete combustion, the carbon in 
 the latter case having united with all the oxygen of which 
 it is capable. Both of these gases, particularly the carbon 
 monoxide, are fatally poisonous if freely inhaled. 
 
 Water has been proved to exist in the products of 
 combustion of certain fuels which, before their combus- 
 tion, were known to contain neither oxygen nor water, 
 but to contain hydrogen. This water, therefore, must have 
 been specially formed during the combustion by oxygen 
 from the air uniting with hydrogen of the fuel. Such 
 water passes off in the form of steam, and finally as 
 vapor, together with other vapors, accessories, and 
 products of combustion, as does water which has been 
 incidentally added to the fuel. 
 
 Although carbon dioxide and carbon monoxide are 
 the chief products of combustion, there are always acces- 
 sory gases and volatile products which also pass upward 
 in the current that rises from the fire. These have just 
 been in part referred to, but summarily stated they are, 
 
14 HOUSEHOLD FUELS 
 
 first, the nitrogen with which its atmospheric associate, 
 oxygen, has parted to take the leading part in combus- 
 tion ; second, water, which the fuel may have acquired 
 before burning; and third, impurities in the air which is 
 supplied to the burning fuel. There may also be some 
 water originating as was described in the next preceding 
 paragraph. 
 
 All the solid fuels, hardly excepting the densest 
 mineral coals, so readily absorb water from the earth 
 and atmosphere that some water in the form of vapor 
 accompanies the products of their combustion, as well as 
 the accompanying gases, which are invisible, and there- 
 fore give one the feeling that they have been totally 
 destroyed. The fuel, as such, has been destroyed, but 
 each of the elements of which it was composed has only 
 changed from one of its conditions to another. 
 
 Without doubt, also, the three rare, lately discovered, 
 gaseous elements which are named in the preceding chap- 
 ter, argon, helium, and neon, accompany every upward 
 current of fuel combustion. There is something impress- 
 ive in the subjection of those four quiescent elements to 
 that fiery passage in a process in which they have no part, 
 and whose destination is the same condition as that from 
 which they were taken. They at least emphasize the 
 aggressive action of the oxygen and the greediness of 
 the hydrogen and carbon. 
 
 Ignition. Because the slow process of oxidation 
 which all fuels undergo from exposure to the atmosphere 
 differs from combustion only in the slower rate of its 
 progress, it needs only the addition of fire to start the 
 faster rate, which is called combustion. This initial 
 
HOUSEHOLD FUELS 15 
 
 application of fire to produce fuel combustion is known 
 technically as ignition, but in the household it is known 
 as kindling. No matter how freely fuels will burn under 
 favoring conditions, ignition of all of them must be begun 
 either by fires already produced, or by the production of 
 a small quantity of burning heat that may be communi- 
 cated by intermediate means to the fuelJ^There is a large 
 number of materials which have been, or which may be, 
 thus used for the lighting of fires, but the friction match 
 now in use is the most convenient and effective of them 
 all. In the following paragraphs some of the other 
 materials and various methods of employing them are, 
 however, mentioned to show how earnestly man has 
 sought out methods of replenishing his fires. They also 
 show what is more to the point for our present purpose, 
 that fires may be produced by widely different methods. 
 A very laborious, but a simple and direct primitive 
 method of kindling fires is by rubbing two narrow and 
 perfectly dry pieces of readily combustible wood together, 
 sometimes by holding the pieces at right angles to each 
 other, and sometimes by holding them both in the same 
 direction. Another primitive method of kindling by wood 
 friction is that of rapidly twirling a dry pointed stick 
 in a piece of wood of the same kind, which has been 
 slightly hollowed. In all three of these cases the fine 
 particles of wood which are detached by the friction take 
 fire from the heat which is also produced by it. In these 
 cases ignition of the wood is accomplished without the 
 aid of any other material. All three of these methods 
 are very ancient, and their use lingers only where friction 
 matches are difficult to obtain, or where the production 
 of fire has been part of a religious ceremony. 
 
1 6 HOUSEHOLD FUELS 
 
 A jnethod of fire kindling which has long been known, 
 and which even now is practiced by many savage and 
 semi-civilized peoples, is known as that of the fire piston. 
 This instrument consists of a small cylinder of horn, bone, 
 or metal, a few inches in length, less than an inch in 
 diameter, and having a central bore. The bore is closed 
 at the lower end, but open at the upper end, and is 
 usually less than half an inch in diameter. The piston 
 is made of the same, or a similar, kind of material as the 
 cylinder, but longer, and fits the bore closely. A piece 
 of tinder is dropped into the cylinder and rests upon the 
 bottom. The piston is thrust into the bore only so far 
 as to steady it, and then struck a smart blow upon its 
 upper end. The descent of the piston compresses the 
 air in the cylinder so much and so quickly that it is made 
 hot enough to set the tinder on fire. 
 
 Up to one hundred years ago it was not uncommon 
 among our people to keep a "sun glass," which was a 
 common lens of a couple of inches in diameter, for prac- 
 tical use in kindling fires. It was not difficult to start 
 a fire by concentrating the sun's rays with such a lens, 
 but the frequent absence of sufficiently bright sunshine 
 at the time fire was needed made that method of little 
 practical use. 
 
 The kindling of fire by means of the flint and steel 
 was perhaps the most widely used of the methods which 
 were practiced before the invention of friction matches. 
 This process is very ancient, and iron pyrite probably 
 preceded steel in producing the sparks by the flint stroke. 
 It is even now retained by some savage peoples in regions 
 where that mineral is frequently found. When the edge 
 
HOUSEHOLD FUELS 1 7 
 
 of a flake of flint is struck obliquely upon a small bar 
 of hardened steel, minute bits of the steel are torn off 
 and heated burning hot by the friction of the stroke and 
 the ready action of the oxygen of the air. These brilliant 
 sparks are intensely hot, but they are so small that their 
 heat is quickly lost, and they would therefore be useless 
 if they were not made to fall upon some easily ignited 
 material. Such material is called tinder, and may be of 
 various kinds. 
 
 The kind of tinder which was most commonly used 
 in our colonial households and in those of still later date 
 was made by the charring of pieces of cotton or linen 
 cloth, which process changed the cloth to fibrous char- 
 coal. The delicate fibers of this charcoal tinder instantly 
 catch the hot sparks as they fall from the steel, and 
 produce little burrowing patches of sparks of their own 
 among the threads. Rural housekeepers also occasionally 
 used other substances for tinder, among which was a 
 fibrous kind of decayed wood mingled with a fungous 
 growth, and called "spunk" or "punk." Hunters and 
 travelers sometimes used still other kinds of tinder, but 
 the charred cloth was superior to all other kinds, and the 
 tinder box in which it w^as kept was one of the chief 
 household conveniences. 
 
 With great care it is possible to ignite fine wood 
 kindlings directly from the burning tinder, but usually 
 the amount of fire which is produced in tinder is too 
 small for such ignition, and an intermediary substance 
 for the transfer of the fire is necessary. For this purpose 
 the sulphur match was used. It was generally known 
 as the "brimstone match," and was also made in the 
 household. 
 
1 8 HOUSEHOLD FUELS 
 
 Sulphur is a distinct chemical element, but, although 
 combustible, it is not a fuel. It melts at a comparatively 
 low temperature, ignites from a spark if only a minute 
 quantity is applied, and burns with a bluish, smoky flame. 
 The match was a slender piece of soft wood, one end 
 of which was narrowed nearly to a point and dipped in 
 melted sulphur. The latter was therefore called the dip, 
 a term which has been continued in use for the corre- 
 sponding application to friction matches. The small 
 prepared end of the suphur match was applied to the 
 sparks among the tinder, arid it quickly became ignited. 
 The sulphur flame at once set the hydrogen of the match 
 aflame, which was then ready to be applied to the candle, 
 lamp, or kindling wood, as we now apply the common 
 friction match. 
 
 Early in the nineteenth century a dip was invented 
 which would ignite when the prepared end of the match 
 was thrust into sulphuric acid contained in a small bottle, 
 and quickly withdrawn. That method was not of con- 
 venient use, and the invention was soon followed by that 
 of a dip which would ignite by friction. 
 
 Friction Matches. Several partial successes in the 
 manufacture of friction matches were made before the 
 practical success of the one which was really the direct 
 lineal descendant of the brimstone match. That is, the 
 first really successful friction matches that came into 
 general use were common sulphur matches, each of which 
 had received a second coating of another kind of dip 
 over its sulphur end, which would ignite by friction on 
 a moderately rough surface. Matches of this simple kind 
 are still in use in some parts of our country. 
 
HOUSEHOLD FUELS IQ 
 
 Many modifications of that primitive frictional dip 
 have been made, with the purpose of abandoning the use 
 of unwholesome or dangerous materials which it con- 
 tained, besides others since used. Among the substances 
 that have been used in the preparation of the dip are 
 sulphur, phosphorus, mercury, antimony, and the nitrates 
 of potassium and sodium, besides adhesive and other 
 ingredients. The evil effects of some of these substances 
 upon the health of those persons who are employed in 
 the match manufacture are so great that effort has been 
 made to enforce their abandonment. 
 
 The invention of the so-called safety match has much 
 diminished the danger attending the general use of fric- 
 tion matches, and has at least partially lessened that which 
 has long attended their manufacture. The dip on these 
 matches consists of a mixture that only with great diffi- 
 culty can be made to ignite by friction upon any surface 
 except those which have a specially prepared substance 
 spread upon them. Ignition of the dip material of these 
 matches is caused by chemical reaction between the con- 
 tents of the dip and those of the surface preparation, 
 which must be incited by friction. In the case of the 
 common friction match, friction alone produces enough 
 heat to ignite the dip material ; but in the case of the 
 safety match, although friction is necessary, the character 
 of the dip is such that it will not ignite without the 
 aid of an accessory substance. Because matches are so 
 generally used and so constantly within the reach of 
 every one, even of children, it is evident that some such 
 regulation as prevails with reference to kerosene should 
 restrict the use of matches to some safety form. Every 
 
2O HOUSEHOLD FUELS 
 
 housekeeper should insist on having no other kind in the 
 household. 
 
 Without statistical information one is hardly prepared 
 to realize the extent of business operations which are 
 involved in the manufacture of matches in our own and 
 other countries. A reputable magazine recently published 
 the statement of a competent author that seven hundred 
 thousand millions of friction matches are used by the 
 people of the United States every year. One cannot 
 doubt that the proportion used in other countries is quite 
 as great. This little, familiar article alone, which we use 
 and waste so carelessly, makes an enormous draft upon 
 the world's supply of wood which must soon call for 
 national remedy in the planting and protection of forest 
 trees of suitable kinds for its manufacture. 
 
 Flame Combustion. Mention has already been 
 made of the combustion of the solid fuels, but because 
 the flame fuels are to be described separately in the fol- 
 lowing chapters, consideration of flame combustion is 
 brought forward in this chapter that it might follow the 
 discussion of ignition. X The flame of all the lighting 
 fuels consists of hydrogen and carbon, and when they 
 are burned the hydrogen is the first to ignite. Hydrogen, 
 when pure, burns with a faint bluish flame which gives 
 very little light, but in fuel flames hydrogen is always 
 associated with exceedingly fine particles of carbon, which 
 are heated to the glowing point by the burning hydrogen. 
 It is this glowing, or incandescence, of the carbon which 
 gives the yellowish or ruddy light to the flames. 
 
 The Candle Flame. Among our immediate ances- 
 tors the candle flame was so distinctly associated with 
 
HOUSEHOLD FUELS 21 
 
 the affairs of their every-day life that its name was used 
 to indicate the time of its lighting. For example, notices 
 of public meetings were habitually given to occur at 
 "candle-light" or "early candle-light," meaning approach- 
 ing nightfall, or twilight. *This flame has the same 
 chemical composition as the flame of the solid fuels, but 
 because of its symmetrical shape and nearly uniform size 
 .it has long been regarded not only as the typical house- 
 hold light, but the accepted unit of measurement of the 
 quantity of light which is given off by other flames or 
 other methods. Reduced to exact limits, that unit and 
 its name are still used, even in scientific estimates and 
 specifications. 
 
 In the candle flame also is to be observed the manner 
 of combustion of the chemical elements of which the 
 candle is composed. To illustrate these methods suitably, 
 the candle must be made of one of the semi-solid fuels 
 which is hard enough at ordinary temperatures for 
 cleanly and convenient handling, and pure enough to 
 change readily to an oily substance and then to a gaseous 
 condition, without residue, when heat is applied. The 
 candle is composed of carbon, hydrogen, and oxygen, 
 and, as in all similar combinations, this structural oxygen 
 is believed to be inert during combustion. That is, the 
 combustion of the carbon and hydrogen is accomplished 
 by the oxygen of the air only. When the wick of the 
 candle is lighted, the heat of the flame melts a portion 
 of the candle to an oily condition, which then rises by 
 capillary action to the burning portion of the wick, where 
 it is changed to a gaseous state. It is the increased heat 
 which occurs there that causes the change from a liquid 
 
22 HOUSEHOLD FUELS 
 
 to a gas, and it is the combustion of this gas that gives 
 the flame. 
 
 Within the basal part of the flame there is a space 
 which appears dark by contrast with the next outer 
 portion. This dark portion of the flame consists of un- 
 consumed gas, to which that portion of the candle that 
 was changed to a liquid condition is further changed 
 by the higher heat which it there encounters. The lumi- 
 nous envelope, which constitutes the principal part of the 
 flame, surrounds this dark portion. This luminous 
 envelope is the gas in its first stage of combustion, where 
 the hydrogen and part of the carbon are chemically 
 united with oxygen derived from the air. The remainder 
 of the carbon is quickly heated until it glows, which 
 condition is known as incandescence. As the incandes- 
 cent particles of carbon within the flame pass outward 
 where oxygen from the air has free access, many of them 
 so unite with the oxygen as to form carbon dioxide, 
 which passes off into the air. The part of the flame in 
 which this last named union takes place is the outermost 
 part, and is known as the mantle. It is so slightly lumi- 
 nous as to be almost invisible, but it is the hottest part 
 of the flame. 
 
 Some particles of ununited carbon constantly escape 
 from all flames, the effect of which is often seen on the 
 white ceiling above a gas jet. Also, if a porcelain dish 
 is held for only a moment in the luminous part of the 
 flame it becomes blackened. This black deposit is carbon, 
 a part of which had become incandescent, but was sud- 
 denly cooled by the porcelain dish and deposited upon 
 its surface. Any interference with the flame is likely to 
 
HOUSEHOLD FUELS 23 
 
 cause it to smoke. 'This smoke consists of fine, escaping 
 particles of carbon. 
 
 Lamp Flames. The flame of a lamp having the 
 ordinary twisted or braided wick is like the candle flame 
 in structure, shape, and manner of combustion. The 
 fuel in the lamp is already liquid, otherwise the stages 
 in the process of producing the flame are the same as in 
 the case of the candle. The flame of the alcohol lamp, 
 however, gives no smoke, because of the complete com- 
 bustion of its carbon ; but the flame of the oils, especially 
 of the mineral oils, although burned in good lamps, is 
 much inclined to smoke. This objectionable character of 
 those oils is due to the large proportion of carbon which 
 they contain, some of which escapes oxidation. This evil 
 has been remedied to a great extent by flattening and 
 otherwise changing the shape of the wick tubes so as to 
 present a greater surface of the flame to the air, and 
 by providing devices for directing currents of air against 
 the flame. Among the most effective of these devices 
 is the cylindrical wick, which produces a flame of like 
 shape and allows a current of air to pass up along the 
 inside of it as well as the outside. The large cylindrical 
 glass chimneys, through which a strong current of air 
 will pass upward and be directed against the flame on all 
 sides, very much improve the combustion of these highly 
 carbonized fuels. 
 
 Gas Flames. The structure of the gas flame is the 
 same as that of the candle and oil flames. It has the same 
 central dark portion, the luminous envelope, and the 
 almost invisible mantle. Unlike those flames, however, 
 the gas in this case is already prepared and ready for 
 
24 HOUSEHOLD FUELS 
 
 use without any intermediary process. The gas is con- 
 stantly supplied to the burners by the force which sends 
 it from the gas works. When that pressure is too great, 
 the gas rushes through the burner so rapidly that un- 
 consumed carbon is especially liable to escape, because 
 it has not sufficient time for complete incandescence and 
 oxidation. That excessive flow should be checked at 
 once, because it wastes the .gas, diminishes the light, 
 sends unconsumed carbon into the atmosphere of the 
 room, and produces more or less carbon monoxide by 
 incomplete combustion. The small apertures of the 
 burners are placed opposite each other to so spread 
 the flame that it will present two broad surfaces to the 
 air. A large and efficient cylindrical flame is sometimes 
 produced from a burner consisting of a circle of small 
 apertures, surmounted by a glass chimney. But even 
 under favorable conditions gas flames are liable to more 
 or less variation in efficiency. 
 
 If the amount of air admitted to the burning gas is 
 much too small, the result is a smoky flame. If the 
 amount is great enough for the full oxidation of the 
 carbon before it has had sufficient time for complete 
 incandescence, the result is diminished light. If a large 
 amount of air is admitted to the fuel in its gaseous con- 
 dition, before it reaches the flame, the increased amount 
 of oxygen which that air brings oxidizes all the carbon 
 immediately, the incandescent stage being omitted from 
 the flame in this case. The result is intense heat, but no 
 serviceable light. A burner meeting the requirements 
 of complete incandescence of all the carbon of the gas 
 passing through it without complete oxidation has not 
 
HOUSEHOLD FUELS 25 
 
 yet been produced, but other incandescent lights of re- 
 markable efficiency have been invented. 
 
 The Mantle, or Incandescent Light. These de- 
 vices, which produce a strong and equable light, much 
 superior to that of the most brilliant flame of ordinary 
 gas, accomplish it by the incandescence, not of the carbon 
 of gas, but of a material entirely unconnected with it. 
 It is true that this light is produced by means of a flame 
 of ordinary gas, but the only office of the flame in this 
 case is the production of heat. A blue gas flame is pro- 
 jected upon a small, delicately woven, basket-like struc- 
 ture, called a mantle, causing its instant and complete 
 incandescence, and producing thereby an intense, steady, 
 and pleasant light. In the construction of these fragile 
 mantles several kinds of the earthy minerals have been 
 tried, all of which resist excessive heat, but thorium is 
 the one which is understood to be the most commonly 
 used. It is the mantle only that becomes luminous ; the 
 gas itself gives no perceptible light. This mantle light 
 is far more intense than can be obtained from incandes- 
 cent carbon under any circumstances. The mantle of this 
 light must not be confounded with the mantle of the 
 candle flame. They have no connection with each other 
 except their unfortunate identity of name. 
 
CHAPTER IV 
 
 THE SOLID FUELS: MINERAL COALS, 
 COKE, AND PEAT 
 
 ' I M-IE solid fuels generally are used only to produce 
 -- heat, and not light. One of them, however, bitu- 
 minous coal, is used in the making of illuminating gas, 
 and large quantities of similar gas are obtained from 
 other mineral coals. Moreover, anthracite is almost in- 
 dispensable in the production of water gas, as we shall 
 see in a following chapter, but in this chapter we will 
 consider only the character of the solid fuels as heat 
 fuels. 
 
 The most concentrated of all the solid fuels are the 
 various kinds of mineral coal. These coals differ in kind 
 from one another, but every kind is important. There 
 is no reason to doubt that the method by which the 
 mineral coals have originated was essentially the same 
 for all of them. It is believed that their differences are 
 largely due to the conditions under which they were 
 mineralized. Doubtless all coals were at one time in a 
 condition similar to, if not identical with, that of peat, 
 so that the method of their origination may be illustrated 
 by the statement immediately following; but peat as a 
 fuel will be described in a still later paragraph. 
 
 The Origin of Peat. Peat is in a soft, somewhat 
 plastic condition as it exists in most of the older and 
 deeper deposits, and of a somewhat spongy texture nearer 
 
 26 
 
HOUSEHOLD FUELS 2/ 
 
 the top. It varies in color from a light to a dark brown, 
 and is frequently interspersed with roots and vegetable 
 fiber. It consists of the remains of mosses, sedges, and 
 other herbaceous plants which grow in bogs or on marshy 
 ground and at the shallow borders of ponds. As these 
 plants mature in the autumn, they fall down and are 
 covered by the water in or upon the margin of which 
 they grow, and also by the successive annual accumula- 
 tions of the same kind of materials. The atmosphere 
 is excluded from the fallen plants by the water, and they 
 therefore do not decay as they would if they were to 
 fall upon ordinary ground. Destructive decay of the 
 accumulating vegetable matter is further prevented by 
 antiseptic properties which forming peat possesses. 
 From year to year the accumulations of peat thus pro- 
 ceed, adding to its quantity and increasing the limits and 
 depth of the bog. The plasticity of peat also increases 
 with age, and in wet seasons the bog is liable to burst 
 its bounds and flood the adjacent cultivated land with 
 flowing peat. Well-preserved trunks of large trees have 
 been found buried in peat bogs, that grew in prehistoric 
 times and were probably killed and overthrown in that 
 way. The presence of water in the formation of peat 
 is so necessary that it is never found in arid regions, and 
 the largest bogs now known are in the northern countries 
 of Europe. Deposits of peat are often very small, the 
 more important of them ranging from a few hundred 
 acres to two or three thousand acres. But even the latter 
 are small as compared with beds of coal. 
 
 The Origin of Mineral Coal. There is no doubt 
 in the minds of geologists that all the various kinds of 
 
28 HOUSEHOLD FUELS 
 
 mineral coal are of vegetable origin as regards the fuel 
 substances of which they are composed. Although all 
 the conditions under which mineral coal exists in the 
 earth today are not fully explained by the known origin 
 of peat, that theory of its origin is generally accepted. 
 This view of the origin of the mineral coals implies that 
 during the ages which have passed since the deposits 
 accumulated as peat, disturbances of the earth have 
 caused them to sink beneath bodies of water and to 
 become covered with sedimentary materials which in the 
 course of time changed to rocky strata. This view 
 further implies that the peaty matter, by sharing in the 
 earth's changes which affected the rocky strata, became 
 changed to coal. 
 
 There are other facts besides those upon which the 
 theory of its peaty origin is based which justify one in 
 attributing a vegetable origin to all kinds of mineral coal. 
 Coal consists of the same fuel elements that are found 
 in wood and peat, and it differs from all other substances 
 found in the earth by being subject to true fuel com- 
 bustion. Fossil remains of plants are often found in 
 greater or less abundance in the layers of rock or shale 
 which underlie and overlie the beds of coal, and some- 
 times they are found in the coal itself. Even in anthra- 
 cite, the hardest and most compact of all the coals, faint 
 traces of vegetable structure have been found. It is 
 believed that all these plant remains belonged to a great 
 growth of vegetation of which each deposit of coal was 
 formed. 
 
 It is only in a part of the geological formations that 
 mineral coal is found, and in some regions of the earth 
 
HOUSEHOLD FUELS 2Q 
 
 no trace of it has been discovered. Still, there are only 
 a few countries in which some kinds of mineral coal have 
 not been found. Those districts or regions in which coal 
 is known to exist beneath the surface are usually called 
 coal fields. Some of the coal fields are hiany square 
 miles in extent, while many are smaller. The coal is 
 found in beds, or layers, which vary from a few inches 
 to several feet in thickness, and in many coal fields 
 separate beds occur, at different depths from the surface. 
 The beds are often of great extent, but the depth at 
 which they lie has no definite relation to the surface of 
 the overlying earth. As a rule, beds of coal are parallel, 
 or conformable, with the layers of rock, shale, or clay 
 which lie above or beneath them. In some cases the coal 
 and its associated rocky layers have been so disturbed 
 by the earth's movements that they lie at various angles 
 with the horizon, but in other cases they are nearly 
 horizontal. In all cases mineral coal is obtained with 
 great labor, and often with great risk to human life. 
 
 The mineral coals differ much in character and quality 
 in different regions and in different mines, even when 
 they bear the same name. Some of them are therefore 
 more suitable than others for household purposes, a fact 
 which should always be borne in mind when coal is 
 bought. Besides the vague terms "hard" and "soft," 
 which are commonly used by dealers for the mineral 
 coals, there are more definite terms generally used in the 
 markets. Still, it is difficult to designate by name all 
 varieties of coal, because different names for the same 
 variety, and the same name for different varieties, are 
 often used by dealers and people of different cities. The 
 
3O HOUSEHOLD FUELS 
 
 names anthracite, bituminous, semi-bituminous, non- 
 bituminous, cannel, and lignite have long been in com- 
 mon use, and, although not entirely satisfactory, they 
 are chosen for the present purpose. 
 
 Anthracite. Of all mineral coals and, in fact, of 
 all fuels, there is no more valuable, or more acceptable, 
 fuel for heating purposes than anthracite. It is the most 
 compact and firm in texture of all the mineral coals, 
 and well deserves its popular name of "hard coal." It 
 can be broken into pieces of any desired size ; it breaks 
 with a smooth, bright fracture, and is not inclined to 
 crumble when handled or exposed to the air. When free 
 from mine dust it is the cleanest of all coals, and it has 
 a pleasing, uniform black color. It burns with little or 
 no flame because of the lack of hydrogen in its compo- 
 sition, but when provided with a good draft it burns 
 with a cheerful glow. It consists more nearly of pure 
 carbon than do any of the other coals. It burns with 
 a more intense and steady heat, and for a longer time 
 without replenishing, than do any of the others. There- 
 fore, considered bulk for bulk, it is the most economical 
 of all the fuels. Although there is a considerable pro- 
 portion of ashes left after burning even the best anthra- 
 cite, its ashes are generally free from those hard lumps 
 called clinkers, which are common in some other coals. 
 
 With such a good record of qualities, one naturally 
 regrets that anthracite forms only a small proportion 
 of the coal supply of the world. Most of that which is 
 produced in America is obtained from a field in Pennsyl- 
 vania which occupies only a small part of the state. 
 The next most important anthracite fields now known 
 
HOUSEHOLD FUELS 3! 
 
 are in Great Britain, but it is believed that large quanti- 
 ties of this valuable fuel exist in China. 
 
 Bituminous Coal. This coal, although of a decided 
 stony hardness, is popularly called "soft coal," probably 
 because it crumbles so easily when handled or when 
 exposed to the weather, or perhaps in contrast with 
 anthracite, which is commonly called hard coal. Bitu- 
 minous coal contains a considerable proportion of hydro- 
 gen, and for that reason it gives off flames freely when 
 its fires are first made, after which its large amount of 
 carbon appears as a glowing bed of embers, which 
 produces great heat. 
 
 Bituminous coal is distinguished from other coals 
 in two important respects, namely, from it is produced 
 the highest grade of both illuminating gas and coke. 
 The former comes from its abundant hydrogen, together 
 with some of its carbon, and the latter from its carbon 
 alone. Further mention will be made of both the gas 
 and coke on following pages. Bituminous coal is some- 
 times called caking coal, because a cake, or crust, is 
 often formed on it when burning. This cake is really 
 coke, and its formation when burning distinguishes the 
 coal producing it from other coals which have a similar 
 appearance. When bituminous coal is burned in an open 
 grate it can be seen to fuse more or less completely into 
 a pitchy, bubbling mass, which is due to the bituminous 
 character of a part of its substance. At the same time 
 it gives off much flame and smoke. It is this portion 
 of the coal that forms the cake which has just been 
 mentioned, and being reduced to comparatively pure 
 carbon by the continued heat, it is consumed with the 
 other carbon of the coal. 
 
32 HOUSEHOLD FUELS 
 
 More smoke is produced by bituminous coal than 
 by any of the other mineral coals, unless the fires are 
 carefully managed, especially by having a good draft 
 and adding new coal to the fire in small quantities 
 before it has burned too low. This tendency to smoke 
 when burning, and the large accumulation of dirty dust 
 among the broken pieces of bituminous coal, impairs its 
 value as a household fuel. Still, it is in some respects 
 one of the most valuable coals in use. 
 
 A large proportion of all the mineral coals, not only 
 in our country, but in the world generally, have much 
 the same aspect as bituminous coal, but they lack the 
 superior quality for gas and coke making which that 
 coal possesses. 
 
 Coke. Mention is made of coke in this connection 
 because it is the solid fuel product of bituminous coal. 
 The gaseous product of that coal will be discussed 
 among the gaseous fuels. When bituminous coal is 
 placed in closed retorts, each of which is provided with 
 an escape pipe and highly heated by fires burning under- 
 neath, it is not consumed, because no air can enter the 
 retort to furnish the necessary oxygen to unite with 
 the carbon. The heat is continued and the coal becomes 
 a partially melted, bubbling mass, and its volatile parts 
 all pass off as gas by the way of the escape pipes. When 
 the retorts are cooled the residue which is left in them 
 is coke, a valuable fuel, which is almost pure carbon. 
 The use of those retorts for gas making is explained 
 in Chapter VIII, under the head of Coal Gas. 
 
 Coke has a grayish, semi-metallic luster, and is light 
 and porous. This porous condition is due to the minute 
 
HOUSEHOLD FUELS 33 
 
 bubbles of gas which formed when the coal was in a 
 partially melted condition. Coke burns without flame, 
 and as a heat producer the best quality of it is equal 
 to anthracite, in equal weight. The coke which is made 
 for special use in the industrial arts is generally of the 
 best quality obtainable in the markets. The major part 
 of the coke found in the fuel markets comes from the 
 retorts of the gas works, and the quality is not quite so 
 good as that of the other just mentioned. Coke is a 
 very acceptable household fuel for summer use, as it is 
 clean and burns freely. It is usually sold by measure 
 and not by weight. This custom is probably due to its 
 tendency to increase its weight by absorbing water, 
 which has been known to reach twenty-five per cent. 
 
 Semi-Bituminous Coal. This variety of mineral 
 coal is similar in appearance to bituminous coal, but it 
 shows little of the character of that coal when burning, 
 as it produces much less flame, and the amount of gas 
 which may be obtained from it is very small. It is more 
 cleanly to handle than bituminous coal, but not so cleanly 
 as anthracite. Its free-burning quality, as compared 
 with the latter coal, makes it a desirable fuel for special 
 household purposes. That which is sold in the markets 
 is found in the region adjacent to the Pennsylvania 
 anthracite field, and it is often sold under the name of 
 the mine which produces it. 
 
 In accordance with the generally accepted theory 
 of the origin of mineral coals, it is believed that in 
 some cases after bituminous coal was formed it was 
 changed by some natural process by which it parted 
 with its hydrogen and became anthracite. In accord- 
 
34 HOUSEHOLD FUELS 
 
 ance with this view it is believed that semi-bituminous 
 coal represents an intermediate condition between 
 bituminous coal and anthracite. 
 
 Non-Bituminous Coal. Under this head may be 
 ranged much the larger part of the mineral coals of the 
 world, all of them having the general aspect as well as 
 the black color of bituminous coal. Xone of them, 
 however, produces good coke as compared with that of 
 bituminous coal, and few of them are good gas coals, 
 even when they are efficient heat fuels. Notwithstand- 
 ing those deficiencies, the best of them are among the 
 most acceptable of household fuels. The many varieties 
 of non-bituminous coal are not readily distinguishable by 
 name, and it has become customary to give them the 
 local names of the mines or places from which they 
 are obtained. 
 
 Cannel Coal. This coal is usually dull black in 
 color, but its blackness is sometimes intense. It is of a 
 more or less uniformly compact texture, without the 
 numerous cross fractures which are so common with 
 other coals, and it is therefore not much inclined to 
 crumble upon exposure. Some varieties are so dense 
 and black that it has been used for the manufacture of 
 articles sold as jet. It burns freely, with much flame, 
 which often assumes the shape of candle flames. This 
 fact gave origin to the name, which is a corruption of 
 candle coal. It ignites so easily that it may often be 
 lighted directly from a match, and because of this con- 
 venience and the pleasing effect of the flames it has been 
 much esteemed for use in open fireplaces. Illuminating 
 gas, mineral oil, and paraffin have been obtained from 
 
HOUSEHOLD FUELS 35 
 
 cannel coal, but its average value is not so great as that 
 of some other mineral coals. 
 
 True cannel coal is not found in large quantities in 
 our country, although dealers often sell other blazing 
 coals under that name. Limited deposits, however, have 
 been found in the carboniferous strata of some of the 
 interior states, but the beds which have been found are 
 too thin, and the quality of the coal too poor to pay for 
 mining. 
 
 Lignite. Owing to the brown color of true lignite 
 it is often called brown coal. This fuel is found in the 
 earth, as are the mineral coals already described, and 
 its texture resembles that of both mineral coal and peat. 
 In true lignite more or less woody and herbaceous fiber 
 is distinguishable, which shows that trees, as well as 
 herbaceous plants, entered into its original peaty com- 
 position, and it is the presence of this woody fiber that 
 gave this coal its name. Although the best lignite burns 
 freely, its fuel value seems to be very little greater than 
 that of the best of peat. Very little true lignite has 
 been found in our country, and it need not be discussed 
 as an American household fuel. It has been found 
 mostly in Europe, but the term lignite has often been 
 applied to some of the poorer non-bituminous American 
 coals, especially to some of those which have been found 
 in the western parts of the United States and Canada. 
 
 Peat. Although peat is commercially one of the 
 least valuable of our fuels, it is given general mention 
 with the others because of its assumed relation to the 
 origin of the mineral coals, and of its importance as a 
 fuel in certain regions where other fuels are not avail- 
 
36 HOUSEHOLD FUELS 
 
 able. Peat deposits, unlike those of mineral coal, have 
 no covering except the accumulation of moss and fallen 
 vegetation which grew there, and which have not had 
 sufficient time to change to peat. 
 
 The process of harvesting peat is simple, but labori- 
 ous and dirty. The surplus water is first drained from 
 the bof and its covering of dead vegetation thrown aside 
 
 o o o 
 
 with shovels. Then another kind of shovel, the blade 
 of which is bent longitudinally at right angles, is used 
 to cut the soft peat into angular blocks. These blocks 
 are dried in the open air, just as freshly molded building 
 bricks are dried before they are stacked in the kiln, and 
 the peat is ready for use. 
 
 Even when carefully dried and stored, peat thus 
 prepared is liable to crumble by handling, and in that 
 condition it makes a poor, smoldering fire. Many efforts 
 have been made to improve the burning quality of peat, 
 the most promising of which appears to be its condensa- 
 tion into small blocks. All the methods of accomplish- 
 ing this condensation by pressure seem to have proved 
 unsuccessful as to an increase of fuel value. It has, 
 however, been discovered that if peat is made quite moist 
 and ground to a plastic condition it will dry in masses 
 of considerable hardness, as will brick clay. Peat thus 
 ground and molded into small blocks so shrinks in 
 drying that, when perfectly dry, it has nearly the hard- 
 ness of mineral coal. Such blocks of peat have been 
 successfully used in both open and closed grates and 
 in stoves. Still, even under the best conditions, peat 
 leaves, after it is burned, a large amount of ashes, 
 mingled with some earth. 
 
CHAPTER V 
 
 SOLID FUELS Continued: WOOD 
 AND CHARCOAL 
 
 ONE who is really in sympathy with nature cannot 
 view the felling of a fine, well-formed tree with- 
 out almost the feeling that a crime has been committed. 
 Still, we have become so accustomed to those and similar 
 acts that we view the general destruction of vegetable 
 life for our fuel with even more complacency than we 
 do that of animal life for our food. Such sacrifice of 
 other life for the preservation and comfort of our own 
 seems to be a natural necessity, for it cannot be doubted 
 that all our fuels of every kind, including the mineral 
 coals, have been derived from formerly, or now, exist- 
 ing forms of animal and vegetable life, respectively. 
 
 Undoubtedly, man's first fires were made with wood, 
 and it is even now in many respects an ideal fuel. It 
 is not used very largely in cities, partly because its cost 
 is comparatively greater than that of other fuels, and 
 partly because it requires greater space for storage. It 
 does, however, largely supplement the use of other fuels, 
 especially in summer, and it is almost indispensable for 
 kindling coal fires. A fair knowledge of the composi- 
 tion and manner of combustion of wood adds much to 
 one's interest in a fuel which is so convenient and the 
 burning of which gives so much comfort. 
 
 As in the case of the mineral coals, the combustible 
 37 
 
3 HOUSEHOLD FUELS 
 
 character of wood depends only upon the two fuel ele- 
 ments, carbon and hydrogen : but in some respects there 
 is a great difference between these two general kinds of 
 fuel. For example, anthracite and coke are nearly pure 
 carbon, and they give off no flame in burning 1 : while 
 wood contains a liberal proportion of hydrogen. The 
 latter, together with a portion of the carbon, gives off 
 an abundance of ruddy flames, which are often increased 
 by the presence of resin in the wood. The proportion 
 of carbon is greater than that of hydrogen in all wood 
 fuels, and woods vary greatly from one another with 
 regard to those proportions. The greater the proportion 
 of carbon which a given kind of wo?d contains, the 
 greater is its heating power, because, although the hydro- 
 gen flames temporarily give considerable heat, it is the 
 be 1 of glowing carbon which remains after the flames 
 have ceased that gives off the desired long and steadv 
 heat. 
 
 Although wood fuel burns very freely, there are 
 some natural impediments to its complete combustion. 
 Even after it has been seasoned, as the process of dry- 
 ing out of its natural sap is generally called, it so readily 
 absorbs water from the atmosphere and other sources 
 that no wood is entirely free from moisture unless it is 
 kiln-dried. \Yhen wood is burned, this water passes 
 off as steam with other products of combustion, and 
 takes with it. in a latent condition, much of the heat 
 which has resulted from the burning of the hydrogen 
 and carbon. \Yood. as well as many other fuels, con- 
 tains much oxygen in its composition, but it is believed 
 that this oxygen is not concerned with its combustion. 
 
HOUSEHOLD FUELS 39 
 
 and that only the oxygen of the air is so concerned. 
 That is, it is believed that not only does the oxygen 
 which enters into the composition of wood not act a- a 
 supporter of combustion, but by uniting with some of. 
 its hydrogen forms water, and so reduce* the hydrogen 
 combustion of the fuel. Water formed under such con- 
 ditions is already in the state of superheated steam, and 
 will, as in the former case, carry oft" much latent heat. 
 This question of the chemical production of water in 
 'the process of combustion of oxygenated fuel- seems to 
 be yet an open one, but there is always enough water 
 in the atmosphere to endanger the perfect combustion of 
 wood fuels. In every possible case the free burning 
 of fuels always pays for keeping them perfectly dry. 
 
 Although all kinds of woody growth will burn more 
 or less freely, firewood, for obvious reasons, is obtained 
 from mature trees. There are many hundred kind- of 
 trees growing in our country, most of which are native 
 to the respective districts where they grow. The -supply 
 for the fuel market, however, is usually obtained from 
 a few of the kinds of native trees which grow in its 
 vicinitv. Frugal owners of woodlands generally utilize 
 the "brush." especially for summer use: that is. small 
 branches of the trees and various shrubs which grow 
 among them. \Yoods are generally roughly classified by 
 dealers as "hard" and "soft." especially if their stock 
 consists, as it often does, only of oaks and hickories, 
 on the one hand, and of pines, on the other. This and 
 other similar groupings of firewood are of some con- 
 venience, but they do not give a desired knowledge of 
 trees. It is not practicable to discuss here an extended 
 
4O HOUSEHOLD FUELS 
 
 catalogue of trees, and therefore only those will be men- 
 tioned in the following paragraphs the wood of which 
 is likely to be found in the chief fuel markets of our 
 -country. 
 
 There is great diversity of names by which the re- 
 spective kinds of trees are known to the people of the 
 different regions where they grow. For this reason it 
 is often difficult to state a case clearly when writing 
 about wood fuels. The names for various kinds of trees 
 which are used by botanists are intended to be the same 
 everywhere. The same precision ought to prevail in 
 the use of their common names, but unfortunately the 
 common names are not only various but often irrelevant. 
 
 A few years ago, however, the United States Depart- 
 ment of Agriculture made a strong effort to secure such 
 conformity in the use of the common names of our 
 forest trees as prevails in the use of their botanical 
 names. The Forestry Division of that department has 
 published, in its Bulletin Number 14, a catalogue of the 
 trees of the United States, in which are given both the 
 botanical and common names of the species. The names 
 of the few trees which are specifically referred to in 
 the following remarks are identical with names which 
 are used in the bulletin to which reference has been 
 made. 
 
 Before discussing the various kinds of trees which 
 furnish our firewood, it is desirable to state the charac- 
 teristics of two great groups into which they are 
 naturally divided, because the members of each group 
 have certain fuel characteristics which clearly separate 
 them from each other. 
 
HOUSEHOLD FUELS 41 
 
 One of these botanical divisions bears the name of 
 Angiosperms, and the other, Gymnosperms, or Conifers. 
 Those botanical names are used here because the divisions 
 which they represent have no common names. The chief 
 differences of structure and foliage between these two 
 great divisions are quite apparent to every one. The 
 angiosperms are well and typically represented by the 
 oaks, with their acorns and broad, falling leaves ; and 
 the pines are equally typical of the conifers, with their 
 cones and needlelike, evergreen leaves. As will soon 
 be shown, the wood of each division is distinguished by 
 peculiarities which are quite as striking as are their 
 external characteristics. 
 
 The Angiosperms 
 
 The wood of the angiosperms, considered as fuel, 
 differs in many respects from that of the conifers. 
 Under the name angiosperms are included all those 
 woods to which dealers give the name of hard wood. 
 They include not only oak, hickory, ash, etc., but many 
 comparatively soft woods, as the soft maples, poplars, 
 linden, willow, etc. The free burning of the wood of 
 the angiosperms is due to their hydrogen, and not to the 
 presence of resin, as is the case to a greater or less 
 extent in all the coniferous woods. A considerable 
 amount of ashes results from the burning of the angio- 
 sperms, but it is not excessive. The ashes of the harder 
 kinds contain so much potash that they were formerly 
 almost the only source of supply of that requisite in the 
 domestic manufacture of soap. The wood of the angio- 
 sperms contains proportionately more carbon than does 
 
42 HOUSEHOLD FUELS 
 
 that of the other kinds.. They are therefore more valu- 
 able as ordinary fuel, and the charcoal which is made 
 from them is superior to that of all other kinds of wood. 
 
 The angiospermous trees are proportionately more 
 abundant in the eastern part of our country than are the 
 conifers, while in the western half the reverse is true. 
 For this reason the Eastern fuel markets are more likely 
 to be well supplied with hard woods than are the Western 
 markets. 
 
 As a rule, the fuel value of a kind of wood is in 
 proportion to its density, but other qualities are impor- 
 tant, and the housekeeper is sure to learn by actual use 
 of them to form a correct judgment of the value of the 
 different kinds. For example, in the absence of mineral 
 coal, when a steady, long-continued heat is desired, the 
 hardest woods are necessary, but for quick, short fires 
 in summer the softer woods are more desirable. The 
 following remarks are not based upon systematic tests 
 to which different kinds of wood have been subjected, 
 but are made with reference to well-known general 
 facts. 
 
 In the next following paragraphs mention is made 
 of the principal fuel trees of our country in an order of 
 arrangement which is intended as an estimate of their 
 relative importance. 
 
 The hickories, of which there are nine known species 
 in North America, are doubtless the most valuable of 
 all our woods for fuel. Of these the shellbark and shag- 
 bark hickories are superior to all the others, but they 
 all make excellent firewood. When hickory wood is 
 dry and sound it burns with a clear, bright flame, and 
 
HOUSEHOLD FUELS 43 
 
 when this dies down there remains a glowing bed of 
 embers which will last for a considerable time. The 
 supply of this excellent firewood is unfortunately too 
 small in most regions to meet household demands. 
 
 The oaks come next in fuel value, and, for several 
 reasons, they are the most important of all. The fuel 
 value of the best varieties of oak is nearly equal to that 
 of hickory, but they vary so greatly that the fuel value 
 of a few of them is not very high. Growing in this 
 country there are nearly fifty kinds of oak, and of these 
 much the greater part produce marketable wood. Oak 
 is therefore more plentiful than any other kind of hard 
 wood fuel. White oak is hardly inferior to the best 
 hickory, especially if the trees from which it is obtained 
 have grown separately and on comparatively poor soil. 
 
 There are a few kinds of oak which have compara- 
 tively low fuel value, and they are those which gener- 
 ally grow in low or swampy ground. Indeed, it may 
 be accepted as a rule that the trees of any given kind 
 which have the greatest fuel value are those which grow 
 alone and upon upland soil that is too poor for cultivated 
 crops. 
 
 The wood of ash trees seldom appears in our fuel 
 markets, because, although there are about a dozen 
 species native to our country, ash trees are nowhere 
 abundant. The wood of all the species is similar in 
 character to that of one another, and its fuel grade is 
 about that of the average oak. 
 
 Out of the eight or nine species of maple which are 
 recognized by botanists as growing within the limits of 
 the United States, only two of them furnish a high 
 
44 HOUSEHOLD FUELS 
 
 grade of fuel as compared with the oaks. These are the 
 sugar maple and the black maple, which is closely related 
 to it. 
 
 Although birch trees are comparatively abundant in 
 some parts of our country, they number only about half 
 a dozen species in all. The best of the birches for fire- 
 wood is the black birch, or, as it is often called, the 
 sweet birch. Children and others chew its tender buds 
 and bark for its flavor, which is similar to that of 
 wintergreen. The wood of the other birches is of com- 
 paratively low grade as fuel. 
 
 Sometimes there will be found among the wood as 
 purchased from the dealer sticks of beech, hornbeam, 
 crab-apple, dogwood, plane tree, and honey locust 
 mingled with the oak and other high grade cord wood. 
 The quantity of each of those kinds of wood is always 
 small and their quality fairly good, so their presence in 
 the wood pile is not greatly objectionable. Cotton wood, 
 and all the other poplars, the willow and linden, all 
 furnish soft wood of low fuel value. The elm, black 
 walnut, butternut, and black locust, although compara- 
 tively dense woods, are not of high grade for fuel, as 
 they do not burn so freely as do most trees of equally 
 vigorous growth. Although the chestnut is a strong, 
 sound wood, it is objectionable for open fires because 
 of the sparks which it throws off when burning. 
 
 To make the foregoing suggestions available as to 
 the relative fuel value of each kind of wood, it is neces- 
 sary that one should learn to recognize each of the 
 different kinds by the character of the texture of 
 the wood itself, apart from that of other portions of the 
 
HOUSEHOLD FUELS 45 
 
 trees from which it comes. Such knowledge is worth 
 acquiring, and it is not difficult to acquire it. 
 
 The Conifers 
 
 The conifers, with few exceptions, are evergreens, 
 and their winter foliage presents a strong contrast with 
 the leafless condition of other trees in winter. The 
 woody fiber in all these trees, especially that of pines, 
 is more or less permeated with resin, and the wood is 
 more nearly of uniform grade for fuel, the proportions 
 of resin excepted, than is that of the other kinds. 
 Because of the presence of resin these woods often burn 
 fiercely, and they ignite readily because of their more 
 than average proportion of hydrogen as compared with 
 their carbon. This proportion of hydrogen is so great 
 that the fire is soon burned out. The amount of ashes 
 left after the burning of these woods is ver^ little, and 
 it contains almost no potash. The few hearth coals 
 which are left after the burning of any coniferous wood 
 are soft and crumbly, and the charcoal prepared in kilns 
 from these woods is soft and of low fuel value. 
 
 The kinds of coniferous trees are numerous, and they 
 have a great, but variable, geographical distribution. 
 These trees are much more abundant in the Western 
 half of our country than are any of the angiosperms, 
 but in the interior states conifers of all kinds are rare. 
 In the following remarks reference is made especially 
 to those kinds of conifers with which the housekeepers 
 of our country are most likely to meet. 
 
 There are nearly or quite forty native species of pine 
 in our country recognized by botanists, and there are 
 
46 HOUSEHOLD FUELS 
 
 few or no fuel markets in which some of these kinds 
 are not represented. They are all classed as soft woods 
 by dealers, although, on account of the resin which they 
 contain, they vary in both hardness and specific gravity. 
 Sometimes the differences of kind are roughly indicated 
 by the names, pitch pine, yellow pine, white pine, etc., 
 but these names are often inappropriate. The pitch pine 
 regions of North and South Carolina and Georgia are 
 famous for ponderous timber and other products of the 
 pines. Still, a large part of the pine firewood which 
 comes from those regions to various city markets is of 
 poor quality, some of it very poor. This is perhaps 
 because housekeepers continue to purchase such wood. 
 
 Occasionally there may be found in the fuel markets 
 the wood of spruce, hemlock, larch, cypress, cedar, and 
 juniper (red cedar) mingled with that of the pines. To 
 this admixture there need be no great objection, because 
 the fuel value of those woods is not materially less than 
 that of the average firewood pine. 
 
 The towering sequoias, or "big trees," and the closely 
 related, more abundant redwood trees of the Pacific 
 coast regions are the admiration and wor ler of every 
 one, but on this occasion they can be treated only as 
 fuels. The wood of those trees is among the best of 
 the soft wood fuels, being equal to the best pine, except 
 when a heavily resinous wood is desired. It is very 
 cleanly and attractive in appearance, being free from 
 those accumulations of pitch which make the pines so 
 unpleasant to handle. 
 
 Unusual Vegetable Fuels. In cases of emergency 
 and irremediable necessity, other vegetable substances 
 
HOUSEHOLD FUELS 47 
 
 than wood have been used as fuel, such, for example, 
 as the dried dung of grass-eating animals, compressed 
 weeds, grasses, etc. Here may also be mentioned the 
 occasional use that has been made of Indian corn as fuel. 
 When the rich prairie lands of what was formerly 
 known as our Western frontier were first occupied, the 
 settlers raised abundant crops of corn every year, the 
 market price of which was often very low. Trees were 
 scarce, and the distance from markets and developed 
 coal mines was so great that during the stress of winter 
 weather they were often without sufficient fuel. Their 
 corncribs were full, the contents of which were an 
 excellent substitute for fuel ; for ears of corn burn as 
 freely and give off quite as much heat as does the best 
 of dry wood. One naturally feels a strong aversion to 
 using an article of food fcr fuel, but under the circum- 
 stances that act was not censurable, and the same settlers 
 who burned corn afterward planted and raised on the 
 same farms large groves of fuel trees. We are apt to 
 forget that olive oil and various other fats which are 
 good human food -have been used from time imme- 
 morial as lighting fuels. It is not the purpose here, 
 however, to discuss any fuels except those the use of 
 which is now prevalent and consistent with domestic 
 comfort and convenience. 
 
 Charcoal. When flame accompanies combustion of 
 carbon in the household use of solid fuels, if not accom- 
 panied by smoke, it is not only not objectionable, but 
 often specially agreeable. In household work, however, 
 it is often necessary to have a glowing fire, free from 
 flame and smoke. When it is desired to have a long- 
 
48 HOUSEHOLD FUELS 
 
 continued fire of this kind, anthracite is the best fuel 
 that can be used for the purpose. Both coke and char- 
 coal, however, are ideal flameless fuels, both of them 
 consisting of almost pure carbon, and both burn freely 
 and steadily. 
 
 Charcoal bears the same relation to wood that coke 
 bears to bituminous coal, which has already been dis- 
 cussed. Charcoal is wood which has been freed from 
 its hydrogen and other volatile contents by heat. The 
 crumbling hearth coals which remain after a wood fire 
 are also charcoal, but that which is found in the fuel 
 markets has been produced in kilns specially constructed 
 for that purpose. From the most complete of these 
 kilns we obtain not only the best quality of charcoal, 
 but also many valuable by-products. Among these is 
 wood alcohol, which will be given appropriate mention 
 among the liquid fuels. 
 
 The modern kiln, often called the beehive kiln 
 because of its dome or approximately hemispherical 
 shape, is substantially built of brick. An opening is 
 made at the apex through which the wood is introduced, 
 and which also serves temporarily as a draft exit. At 
 the base are openings to admit air to the kindling fire 
 within, and also a larger opening for the removal of 
 the charcoal. Covers are provided for each of these 
 apertures, so that they may be instantly closed when 
 necessary. When the process is completed and the kiln 
 is cooled, all the products are available, but it is only 
 the charcoal and the wood alcohol with which we are 
 now concerned. 
 
 Charcoal made in a kiln of this kind from good hard 
 
HOUSEHOLD FUELS 49 
 
 wood is a most satisfactory fuel for special purposes, 
 and it is ready for immediate use as it comes from the 
 kiln. The wood alcohol, however, must undergo a 
 somewhat elaborate process of separation from the other 
 by-products before it can be used as a household fuel. 
 The fine quality of charcoal made in these kilns breaks 
 with a clean fracture, which is independent of the grain 
 of the wood, and when the pieces are shaken together 
 in the fuel basket they give forth a faint metallic tinkle. 
 Charcoal made of soft wood does not possess these 
 characteristics, and it is dirty to handle and burns out 
 more quickly. 
 
 Formerly, rude charcoal kilns were made in the 
 forests by woodmen, and such are now occasionally 
 made to supply local demands. The wood is cut in pieces 
 a foot or two in length and stacked on end in a dome- 
 shaped pile on the ground. The pile is then covered 
 with sod and earth, openings being left at the top and 
 base similar to those in the kilns built of brick, which 
 have just been described. The fire is applied within 
 the openings at the base, and when the mass of wood 
 within is burning well these apertures are gradually 
 closed, but the fire within the kiln does not become com- 
 pletely extinguished until the charring is complete. The 
 hydrogen and all other volatile products pass off through 
 the summit aperture, no effort being made by the wood- 
 men to save them. The ^charcoal only remains, and is 
 obtained by removing the sods and destroying the kiln. 
 Charcoal made in this rude way is sometimes good, but 
 it does not generally make a very satisfactory household 
 fuel because of the frequent presence in it of uncharred 
 pieces of wood and dirt from the kiln covering. 
 
5O HOUSEHOLD FUELS 
 
 Tar and Resin-. The woodmen of some of the 
 Southern pine forests frequently construct kilns, not for 
 the production of charcoal, but tar, the substance which 
 is proverbially associated with the life of the sailor. 
 Tar is not a fuel, but the method of its production is 
 mentioned here because it is an inversion of the method 
 of charcoal production and a destructive one of wood 
 distillation. 
 
 The tar kiln is a hole of inverted conical shape, dug 
 in the earth at the brow of an abruptly sloping bank,, 
 so that it may be easily drained out upon the lower 
 ground surface. ' It is six or eight feet in diameter at 
 the top, but only a foot and a half at the bottom, where 
 an iron pan is fitted which has a drainage spout. The 
 kiln is filled with short pieces of pitchy pine and fired 
 at the top. The fire burns downward, causing the resin 
 to ooze from the wood and mingle with the other 
 products of wood distillation. The mixture is tar, and 
 it gathers in the pan at the bottom of the kiln and passes 
 out by its spout to the receptacle. 
 
 Pure resin is produced from pine trees similar to 
 those which produce tar, but it is obtained in quite a 
 different manner. Wounds are made in the trunks of 
 living trees, and from these the viscid pitch exudes, 
 which consists of resin and oil of turpentine. The pitch 
 is distilled in water, that it may not be scorched ; the 
 volatile oil of turpentine passes off and is secured. The 
 remainder is commercial resin. 
 
CHAPTER VI 
 THE SEMI-SOLID FUELS 
 
 ' I V HE solid fuels are used only as hetit producers; 
 * even the .flame, which accompanies the combustion 
 of some of them, is utilized for heat and not for light. 
 The semi-solid fuels, on the other hand, are adapted to 
 the production of light only. These fuels are completely 
 consumed in combustion, and, if pure, they leave no 
 residue of any kind. Some of them are still used in the 
 household for convenience, but their use has been greatly 
 lessened by the introduction of the mineral oils. Only 
 those which are, or have been, much used in the house- 
 holds of our country are mentioned in the following 
 paragraphs. These fuels vary in consistency from that 
 of lard to that of beeswax and resin. All of them melt 
 at comparatively low heat and return unchanged to their 
 original semi-solid condition on cooling. 
 
 The semi-solid fuels which have been selected for 
 mention are fat, wax, stearin, palmitin, spermaceti, and 
 paraffin ; and to these resin is added because of its con- 
 nection with the origin of oil of turpentine, one of the 
 liquid fuels. The five first named semi-solid fuels are 
 sometimes spoken of as oxygenated hydrocarbons, be- 
 cause they consist not only of hydrogen and carbon, 
 but also contain a proportion of oxygen. Although the 
 sixth kind, paraffin, resembles spermaceti, stearin, and 
 palmitin in appearance, it is a pure hydrocarbon, being 
 composed of hydrogen and carbon only. 
 
 5 1 
 
52 HOUSEHOLD FUELS 
 
 Fats. Generally, one is apt to think of fats as animal 
 substances rather than as vegetable products. It is true 
 that many of the fats used in the household are animal 
 fats, but true fats are furnished by the nutlike fruits of 
 many and widely different kinds of plants. Some of not 
 only the animal, but of the vegetable fats consist of two 
 parts, both of which are combustible without residue. 
 As the fat is seen under ordinary observation, these parts 
 are apparently inseparable, but methods for separating 
 them completely have long been in use. One of the parts 
 is an oil and the other is a semi-solid, such as are now 
 under discussion. The proportion of these two parts 
 differs considerably in the fat of different animals ; for 
 example, that of the ox differs greatly from that of the 
 hog. The proportion also differs considerably in the fat 
 of individual animals of the same kind, according to the 
 food with which they have been fed. 
 
 It is a fact well known to thrifty farmers that the 
 fat of corn- fed hogs is much firmer than is that of those 
 which are either swill- fed or mast- fed. The lard made 
 from the fat of mast-fed hogs is sometimes so soft that 
 it becomes liquid with summer heat of the atmosphere. 
 On the contrary, the kidney fat of the ox and sheep is 
 almost of waxy hardness after it has been freed from 
 its animal tissue by melting, because the oily part of the 
 fat is only slightly represented. 
 
 There is now no occasion for the use of any of the 
 fats as household fuels without separating their oily from 
 their semi-solid portions, but formerly lard was occasion- 
 ally and tallow very extensively so used. A brief descrip- 
 tion of the manner of using' those two fuels for lighting 
 
HOUSEHOLD FUELS 53 
 
 purposes will be of interest, because it will show how 
 important certain articles formerly were in the household 
 that would not now be tolerated. 
 
 Lard Lamps. In the early part of the nineteenth 
 century tallow was constantly used for candles through- 
 out the whole breadth of our country, but upon what 
 was then our Western frontier lard was frequently 
 burned in lamps just as it came from the rendering 
 kettles. This use of lard for lighting fuel was mainly 
 confined to the region referred to, because hog products' 
 were abundant and cheap there ; but the practice was not 
 prevalent elsewhere, and it did not last many years. 
 This use of lard is mentioned here to show one of the 
 various expedients to which our people resorted to 
 obtain household light. The lamps so used were much 
 like those in which whale oil was burned, but because 
 it was necessary to have the lard in an oily condition 
 before it would rise in the wick it was melted in another 
 vessel and poured into the lamp. Sometimes, to avoid 
 this extra labor, a narrow strip of copper was attached 
 to the side of the wick tube, reaching from the lard to 
 the top of the wick. Sometimes the whole wick tube 
 was made of copper, but as it soon collected verdigris, 
 that use of it was objectionable. Copper is such a good 
 conductor of heat that it soon melted enough of the 
 lard to start an upward flow in the wick when a 
 flame was held a short time to its upper end. In this 
 way the lamp was lighted and gave what was then ah 
 acceptable flame. 
 
 Tallow Candles. At the time referred to in the last 
 paragraph, the use of the tallow candle was universal, 
 
54 HOUSEHOLD FUELS 
 
 and the preparation of the candles and of the tallow to 
 make them was one of the important labors of the house- 
 hold. Indeed, the use of such candles was to our 
 ancestors an ancient custom, and they evidently accepted 
 its inconveniences as inevitable. 
 
 Among our people, rendered tallow was a common 
 article of merchandise at the village stores, and the 
 butcher sold his candle tallow with his meats, in which 
 case the rendering of it was added to the labor of the 
 housekeeper. The candles which she made were either 
 molded or dipped, the latter process being the more 
 ancient household art. 
 
 For dipping candles, a deep iron kettle was placed 
 over a fire, partly filled with water. When the water 
 boiled, enough rendered tallow was put into the kettle 
 to bring its melted surface near the top. The tallow, 
 of course, floated upon the water. The candle wick- 
 ing, which consisted of loosely twisted cotton threads, 
 was cut into lengths double the length of the candles to 
 be made. These wicks were folded over a slender rod 
 of wood and the two parts slightly twisted together. 
 About half a dozen of these wicks were suspended from 
 each of the rods, each wick being little less than a quarter 
 of an inch in diameter. The wicks, dangling from the 
 rods, were dipped into the melted tallow, the upper ends 
 being held above its surface by the rods, which extended 
 across the kettle. The dipped wicks were immediately 
 hung upon a frame to cool, and were straightened with 
 the fingers. When cooled, the incipient candles were 
 dipped and quickly removed again and again until they 
 were of the desired thickness. These candles were much 
 
HOUSEHOLD FUELS 55 
 
 like the candles of today, but they were exceedingly crude 
 and unsightly objects. 
 
 The molding of candles did not find its way into 
 American households until after the first third of the 
 last century. Previous to that time it had been practiced 
 as a chandler's art, and the candles so made were used 
 in churches and public places. The candle molds which 
 were first introduced for household use were made of 
 sheet tin, and soon became an article of merchandise, 
 together with other tinware. They were cylindrical 
 tubes, usually made in groups of three, four, or six, and 
 slightly larger at one end than the other. There was a 
 conical-shaped cover, with a hole in its apex, through 
 which the wick was passed, which closed the smaller end 
 of each mold. At the larger and open end the wick was 
 held in place by a small, transverse, wooden rod. The 
 melted tallow was poured into the larger end, filling 
 each of the tubes. As tallow shrinks slightly on cooling, 
 the candles were easily withdrawn. 
 
 The same large wicks were used for these candles 
 that were used for those that were dipped. Such wicks 
 were only charred, not consumed, as the candle burned 
 down, and the light was thereby much diminished. It 
 was therefore frequently necessary to remove the charred 
 wick with snuffers, which were kept constantly at hand. 
 The small braided wicks which are now used in candles 
 were not then known. These small wicks turn aside 
 to the air as the candle shortens, and the end is there 
 consumed to ashes and needs no snuffing. 
 
 Wax. The known varieties of wax are not only 
 numerous but diverse, some of them being of animal 
 
56 HOUSEHOLD FUELS 
 
 and others of vegetable origin. There are also some 
 mineral substances which are waxlike. Only two of the 
 substances which are called wax need to be mentioned 
 here, as most of those so-called have no place among 
 household fuels. These two are beeswax and the wax 
 which is obtained from the bayberry shrub, or wax 
 myrtle. Indeed, the practical use of both of these sub- 
 stances as accessory light fuels long ago passed away. 
 
 Crude beeswax is only melted honeycomb, and was 
 used in that condition to harden tallow candles for 
 summer use. When beeswax is refined and bleached it 
 is of nearly pure white color, and was formerly much 
 used upon religious and other important occasions, but 
 it seldom made its appearance in the household in that 
 refined condition. 
 
 Myrtle wax is formed as a slight grayish film on the 
 outside of the small, spherical, seed-like fruits which grow 
 in clusters on the bayberry shrub. This shrub is found 
 growing on open waste grounds of the Atlantic coast 
 region, from Nova Scotia to Florida. The fruit is placed 
 in large kettles nearly filled with water, which is boiled 
 until the wax floats upon the surface. The refuse is 
 removed, and when the water cools the wax forms as 
 a crust upon its surface. Sometimes candles have been 
 formed of this wax alone, but its former domestic use 
 was only to harden tallow candles. Because this wax was 
 never abundant, it was never extensively used. 
 
 Impurities, or small bits of any kind which were left 
 in the tallow when it was rendered, or in either of the 
 two kinds of wax when added to the tallow, made the 
 candles "gutter," and thus increased their inefficiency 
 
HOUSEHOLD FUELS 57 
 
 and ugliness. When no wax was obtainable, alum was 
 sometimes added to the tallow to harden it, but as alum 
 interfered with the burning of the candle and lessened 
 the amount of its light, that method of hardening was 
 seldom used. 
 
 Stearin. Chemists know this substance as stearic 
 acid, but the commercial name is stearin, and that name 
 is generally used in the household. Stearin is found in 
 animal fats, and some chemists recognize the correspond- 
 ing semi-solid of vegetable fats also as stearin, and not 
 always as palmitin. It is separated from its oily associate 
 by a process which leaves the latter in a permanently 
 liquid condition. It was the stearin of the fat of hogs 
 and other domestic animals that first caused the retire- 
 ment of the tallow candle. The common candle now in 
 use, however, is usually made of paraffin, stiffened with 
 beef stearin. 
 
 Palmitin. This substance bears the same relation 
 to the fats of certain kinds of palms and other trees 
 that stearin does to the animal fats. The semi-solid part 
 of that vegetable fat is known as palmitin, but it is so 
 closely like stearin in appearance and use that the house- 
 keeper will generally not care to distinguish them apart. 
 Its associated oil is palm oil, which is much more used 
 in the industrial arts than in the household. 
 
 Spermaceti. Few substances of its kind have been 
 longer or more favorably known than spermaceti. It 
 is the semi-solid part of the fat obtained from the whale, 
 mostly the sperm whale, and bears the same relation to 
 their fat that stearin does to other animal fats. The best 
 spermaceti is obtained from the oily fat which is found 
 
5 HOUSEHOLD FUELS 
 
 in certain parts of the head of the sperm whale. It is 
 among the most beautiful and satisfactory of all the 
 substances which have been used for making candles. 
 When thoroughly purified, its slightly translucent white- 
 ness makes a candle of this substance a pleasing and 
 striking object. It is still occasionally used to make 
 candles for the use of those whose aesthetic tastes prefer 
 its slender flame to the brilliant glare of those illuminants 
 which have driven the candle from common use except 
 as a small portable light. 
 
 Paraffin. This name has been used to denote various 
 substances, but by the term as here used is meant the 
 waxy, white, translucent mineral product which is gener- 
 ally recognized by that name in our country. Sometimes 
 it is found more or less pure in the earth, but most of 
 that which is sold in the markets is obtained from petro- 
 leum, and is now abundant. In former years it was 
 obtained in comparatively small quantities from certain 
 kinds of mineral coal, and even from peat. 
 
 Paraffin is used for various purposes, but its use as 
 a household fuel is only in the form of candles. Such 
 candles burn with a good flame, and the best of them 
 are sometimes sold for wax or spermaceti. Candles 
 made from paraffin alone have a good appearance, but 
 they become so softened by summer heat that they often 
 bend over and lose their shape. It is for this reason that 
 the candles which are sold in the markets consist largely 
 of paraffin stiffened with beef stearin. 
 
 Resin. The name resin is applied to many different 
 substances in medicine and the arts. As found in the 
 markets, the -substance here referred to is in brown, 
 
HOUSEHOLD FUELS 59 
 
 brittle, translucent lumps, which break with clean but 
 irregular fractures. Although it melts at comparatively 
 low temperature, it returns to its original condition on 
 cooling. When it exudes from wounds which are made 
 through the bark of pitch pine trees it has about the con- 
 sistence of honey, but it acquires a brittle hardness after 
 long exposure to the air, or after it has been artificially 
 freed from its oil of turpentine. Its only place among 
 the household fuels of the present day is its occasional 
 application to the ends of kindling wood, that they. may 
 ignite more readily. It was formerly used in the making 
 of links, or torches, to light the entrances to large dwell- 
 ings, especially upon gala occasions. The manner of 
 preparing resin for the market has already been men- 
 tioned in connection with that of producing tar from 
 the wood of pine trees. 
 
CHAPTER VII 
 THE LIQUID FUELS 
 
 TT has been shown that the semi-solid fuels produce 
 * flame with comparatively little heat, and that they 
 leave no residue of any kind. We are now to see that 
 this is precisely the case with all liquid and gaseous fuels, 
 and that these three kinds form a section which is quite 
 different from the section formed by the solid fuels. 
 
 Every liquid fuel is ready at all times to pass up 
 through the lamp wick, or a piece of asbestos in some 
 cases, by capillary action, there to be quickly changed 
 to a gaseous condition and completely burned. All the 
 semi-solid fuels are used in the household only in the 
 form of candles, and the manner of their combustion 
 may be conveniently observed. When the wick is lighted 
 the substance of the candle is melted by its heat to 
 the condition of oil. This newly formed oil passes up 
 through the candle wick just as ordinary oil does in the 
 lamp wick. Thus all the semi-solid fuels are reduced 
 to a liquid, and from a liquid to a gaseous condition 
 before they are burned, and, like the gaseous fuels, they 
 leave no residue after burning. These facts show that 
 the semi-solid fuels are really only congealed liquid fuels 
 so far as the production of flame is concerned, their 
 difference of condition being only one of temperature. 
 Pursuing that idea still farther, we shall see that the 
 liquid fuels and the liquefied semi-solid fuels are only 
 
 60 
 
HOUSEHOLD FUELS 6l 
 
 condensed gases, the difference in each case of practical 
 use being only that of temperature. 
 
 The liquid fuels may be divided into two general 
 classes, oils and alcohols. There are several groups of 
 oils and many kinds in each group, but kinds belonging 
 to only two of the groups have been used as household 
 lighting fuels. These are, first, the true oils, sometimes 
 called the organic oils, or fats of either animal or vege- 
 table origin ; and second, the mineral oils, which are true 
 hydrocarbons, although the term oil has become insepa- 
 rably connected with them. Because the true oils contain 
 oxygen besides carbon and hydrogen, they are sometimes 
 called oxygenated hydrocarbons. Some of these oils of 
 both animal and vegetable origin may be used as liquid 
 fuels just as they were obtained from their respective 
 sources, but others of each kind must be separated from 
 a semi-solid substance with which they are associated in 
 their origin before they can be so used. The two oils 
 which are mentioned in the next paragraph illustrate the 
 conditions referred to. 
 
 Olive and Palm Oils. These two oils not only 
 serve to show the relation of vegetable oils to one 
 another, but also the relation of a part of them to the 
 semi-solid fuels. These examples also show the similarity 
 of animal and vegetable oils as fuels. Both olive and 
 palm oil are among the oldest known oils used as light- 
 ing fuels, but neither of them has ever been practically 
 used for that purpose in American households. In its 
 crude state palm oil is associated with the well-defined 
 semi-solid substance, palmitin, but olive oil is nearly free 
 from such an associate. The flocculence which is seen 
 
62 HOUSEHOLD FUELS 
 
 in even the purest olive oil in very cold weather is due 
 to the presence of a small quantity of stearin, but that 
 flocculence quickly disappears by the liquefaction of the 
 stearin as the temperature rises. Olive oil has been used 
 from time immemorial, and its religious as well as its 
 secular associations make one almost feel a veneration 
 for it. We have every reason to believe that it was the 
 first oil that was used to light human dwellings. 
 
 Whale Oil and Lard Oil. Lard oil is one of those 
 animal oils to which reference has been made as being 
 organically associated with stearin in fats in large and 
 easily obtainable quantity. This oil is now mentioned 
 only to compare it with whale oils, which are almost 
 free from stearin as they are originally obtained. The 
 mention of lard oil again is not for its importance, but 
 for the purpose of referring to the historical fact of its 
 brief domestic use as a household lighting fuel before 
 the discovery of petroleum by deep boring in the earth, 
 which occurred in 1859. That discovery was made when 
 lard oil was used in those parts of our country where 
 hog products were cheap enough to compete with whale 
 oil. That competition, however, was of limited extent 
 and short duration, and it was ended by the introduction 
 of mineral oils to the household, which also ended the 
 use of whale oil in household lamps. 
 
 Up to the time of that discovery of petroleum in 
 Pennsylvania, whale oil was the most serviceable light- 
 ing fuel then to be obtained in our country, and was 
 more generally used than any other except the tallow 
 candle. The oil of the Greenland whale was the kind 
 then commonly used, but that of the sperm whale was 
 
HOUSEHOLD FUELS 63 
 
 the best and also the most expensive lamp oil then in use 
 among our people. Those oils were generally used just 
 as they came from the rendering kettles of the sailors, 
 who also carried on a sort of rude chandlery on ship- 
 board for separating the spermaceti from its associated 
 sperm oil. 
 
 Before the great discovery of petroleum in Pennsyl- 
 vania, fishing on the high seas for whales from which 
 to obtain oil was among the great business enterprises 
 of that time. For many years good catches of whales, 
 grampuses, porpoises, and seals were made upon com- 
 paratively short voyages by the crews of the smaller 
 vessels, but the great whaling enterprises were prose- 
 cuted by means of well-manned ships which sailed from 
 New Bedford and Nantucket as far as Bering Sea, by 
 way of Cape Horn. The average time required for the 
 round voyage of each vessel was about four years. 
 Notwithstanding such length of the cruises, there were 
 so many of the vessels sailing from those two ports alone 
 that their general sailing course was a great marine 
 highway. The large amount of oil which was then 
 taken by those ships found its way into almost every 
 home in our country, until its use was brought suddenly 
 to an end by the flooding of the markets with mineral 
 oil. It is thought well to repeat this reference to that 
 fact because it relates to one of the most sudden revo- 
 lutions that have occurred in domestic usage. 
 
 At the present day our households are so easily and 
 brilliantly lighted that it is difficult to understand how 
 the housekeepers of those early days accomplished any 
 work in a suitable manner during the long evenings, with 
 
64 HOUSEHOLD FUELS 
 
 their poor and inefficient lights. The lamps which were 
 used for whale and other oils were usually made of 
 japanned tin, and held less than half a pint of oil. The 
 flame of those lamps was clearer than that of the tallow 
 candles, but little if any larger. The lamps were as 
 uncleanly as the candles, if not more so, for oil constantly 
 escaped from the screw-joint of the wick tube and spread 
 as a film over the whole outer surface of the lamp, so 
 that it required frequent wiping. Every housekeeper 
 can see how almost impossible it would be to keep delicate 
 goods from becoming soiled by such lamps. 
 
 When we consider the inefficiency and inconvenience 
 of the only household, lighting fuels that were available 
 in those early days, we do not wonder that our people 
 were constantly looking for something better. It was 
 of such necessities that our present splendid system of 
 household illumination was born. The trials which our 
 frugal people gave to various products, as already men- 
 tioned, showed their habit of inquiry, which is still 
 further indicated in the next paragraph. 
 
 Oil of Turpentine. This oil, being very combusti- 
 ble, was thought by a few persons to promise well as an 
 illuminant, and it was so used to some extent before the 
 general introduction of mineral oils. Alcohol was mixed 
 with it and the mixture sold under the name of "cam- 
 phene," or burning fluid. The lamps in which it was 
 burned were similar in size and shape to those used for 
 whale oil, but each had a slender wick tube, which was 
 provided with a small metal cap to extinguish the flame. 
 This fluid mixture proved to be explosive and therefore 
 exceedingly dangerous in the household. Its use was at 
 
HOUSEHOLD FUELS 65 
 
 best only an experiment, and it soon went out of use. Its 
 brief mention here is only to show how earnestly the 
 people were groping for better light, and how often they 
 failed. 
 
 Oil of turpentine is a true oil of the -volatile group, 
 but it is commonly known as spirit of turpentine ; and 
 house painters, who use great quantities of it, usually 
 shorten the name to "turpentine." Like all true oils, 
 it contains oxygen in addition to hydrogen and carbon, 
 but unlike those oils it is volatile. 
 
 Mineral Oils. The lighter grades of mineral oil are 
 quite as volatile as the oil of turpentine, but they are all 
 true hydrocarbons, being composed of hydrogen and 
 carbon only. The mineral oils have become so impor- 
 tant, not only in the household but in the industrial 
 world, that facts relating to their discovery in large 
 quantity, and to the character of the crude oil and its 
 refined products, are of unusual interest. The crude oils 
 are obtained from two sources. One of them, which is 
 called petroleum, is obtained directly from the earth by 
 borings like those of artesian wells ; the other, commonly 
 called coal oil, is obtained by distillation of certain kinds 
 of mineral coal or of bituminous earth, or shale. Crude 
 coal oil and petroleum are practically identical in com- 
 position and character. Both have a varying brownish 
 color, and both also vary in density according to the 
 proportions of the refined products which may be 
 obtained from them. 
 
 Refiners have recognized not less than seven grades 
 of refined oils from petroleum besides the semi-solid 
 products, paraffin and vaseline, all of which are pure 
 
66 HOUSEHOLD FUELS 
 
 hydrocarbons. All grades of the refined oils mix readily 
 with one another in all proportions and at all temper- 
 atures of the atmosphere. The following names have, 
 at various times, been applied to those grades, beginning 
 with the lightest : cymogene, rhigolene, gasoline, naphtha, 
 benzine, kerosene, headlight oil, and lubricating oil. 
 Refiners generally now retain only the following names : 
 lubricating oil, which is the densest grade and is used 
 for lubricating heavy machinery ; headlight oil, which is 
 used for headlight lamps of locomotive engines ; kero- 
 sene, the commonest of household heating and lighting 
 liquid fuels ; and gasoline, sometimes used in the house- 
 hold for fuel, but more often used in the industrial arts 
 and for motor engines of various kinds. 
 
 All the other names for the successive grades of oil 
 lighter than kerosene have been abandoned by most 
 refiners and dealers, each grade having received the 
 name gasoline with the addition of a number. That is, 
 benzine is gasoline i ; naphtha is gasoline 2 ; gasoline 
 is gasoline 3 ; rhigolene is gasoline 4 ; and cymogene is 
 gasoline 5. All these lighter grades of mineral oils, as 
 well as carefully tested kerosene, are, to the casual 
 observer, simply transparent liquids, having the same 
 general aspect and all readily and permanently mixing 
 together. They also all contain the same two chemical 
 elements, namely, carbon and hydrogen. 
 
 Kerosene, as well as the two heavier oils, headlight 
 and lubricating, if properly graded are inexplosive. All 
 the grades of gasoline, however, especially numbers 4 
 and 5, are so volatile that there is constant danger of 
 their explosion when used in the household for any 
 
HOUSEHOLD FUELS 67 
 
 purpose. Because several of the names which were 
 formerly used for the lighter grades of mineral oils by 
 refiners and dealers have been discontinued by most 
 dealers, only the names kerosene and gasoline will now 
 be used in this essay for the mineral oils t which have a 
 place among household fuels. 
 
 Tests of Kerosene. The lighter oils mix so readily 
 and completely with kerosene that it is impossible to 
 detect the mixture by sight. The danger of using such 
 a mixture made it necessary that standards of grade 
 should be fixed by law and municipal regulations, which 
 has accordingly been done in all civilized countries. 
 Formerly there was a constant inducement to violate 
 those laws and regulations, because the lighter oils were 
 the cheaper and it was easy for any person to make the 
 mixture. There has lately arisen a greatly increased 
 demand for the lighter oils and a consequent increase 
 in their price, until it exceeds that of kerosene. There- 
 fore the chief, if not the only, inducement to adulterate 
 kerosene has been removed. 
 
 The standard tests which have been established by 
 law are based upon the specific gravity of the oil to be 
 tested, and on what is called its flashing point. Formerly 
 a test was used which was called the burning point, but 
 the flashing test is much the more efficient, and is prac- 
 tically the only one now used. The original way of 
 determining the flashing point was to place some of the 
 oil to be tested in an open cup and to heat it slowly. 
 A thermometer was placed in the oil and the temperature 
 noted at which sufficient gas was given off to cause a 
 slight explosion when a lighted match was applied. 
 
68 HOUSEHOLD FUELS 
 
 Now, however, there are specially constructed instru- 
 ments in use, called oil testers, by which the flashing 
 point can more easily and accurately be determined. 
 The flashing test is regarded as absolutely essential by 
 all authoritative regulations, the requirements of which 
 vary from 110 to 200 F. In some of the states 
 municipal regulations require the last named flashing 
 point, which is the highest test required in any country. 
 
 To determine the specific gravity of kerosene, an 
 instrument called a hydrometer has been used, and the 
 required rate by that test has varied from .807 to .880. 
 Some municipalities, however, consider this test as of 
 little importance, and therefore do not include it in their 
 regulations. Owing to these state and municipal regu- 
 lations and the removal of inducement to adulterate 
 kerosene, the use of that fuel is likely to be safe in our 
 households. 
 
 The well-known odor which arises from gasoline 
 and impure kerosene is usually due to the vapor of 
 gasoline only, but sometimes a sample of kerosene which 
 has stood the strictest tests of flashing point and specific 
 gravity will have a strong odor somewhat similar to that 
 of gasoline. In such cases the odor is due to the pres- 
 ence in the liquid of a small amount of sulphur, which 
 it has been found very difficult to remove. Its presence, 
 fortunately, is only unpleasant, not dangerous. Such 
 presence of sulphur in petroleum is usually confined to 
 certain regions. 
 
 Gasoline. It has already been mentioned that 
 dealers have begun to designate all the mineral oils 
 which are lighter than kerosene by the one name, gaso- 
 
HOUSEHOLD FUELS 69 
 
 line, and that numbers are now used instead of the 
 former grade names. The gasolines are all explosive, 
 and some of them highly so. Still, even the lightest 
 grades may be safely used by a competent and careful 
 person; but so many terrible accidents have happened 
 in connection with its use that it should not be admitted 
 to the household, even for other than fuel purposes. 
 This judgment of the danger in using gasoline has 
 caused the authorities of New York City to forbid the 
 use of the gasoline stoves in any house, and like regula- 
 tions are becoming common in other cities. Insurance 
 companies also require that gasoline shall not be used 
 in any house they insure. 
 
 The fact that coal oil and petroleum are practically 
 identical naturally suggests that petroleum originated 
 from coal in the earth ; but there are many known facts 
 which are opposed to that belief. Although it is true 
 that some petroleum has been found in strata which 
 overlie and underlie beds of coal, yet no petroleum has 
 been found free in any of those coal beds. Also it is 
 certain that the great oil fields of the world have no 
 connection with coal fields. However, it is the general 
 belief of geologists that petroleum has originated from 
 the remains of plants, and perhaps in part from the 
 remains of animals, that formerly existed. Still, it is 
 proper to mention that a noted Russian chemist opposes 
 that view, and claims that petroleum is of. chemical 
 origin in the earth. 
 
 Alcohols. There are several kinds of alcohol known 
 to chemists, but only two of them are usable as house- 
 hold fuels. These are ethyl alcohol, commonly called 
 
7 HOUSEHOLD FUELS 
 
 grain, or ninety-five per cent, alcohol, and that which 
 is obtained from wood, or wood alcohol. They are both 
 limpid, colorless liquids, which will ignite at the touch 
 of flame and burn with a strong flame of their own, 
 which gives much heat but little light, and no smoke 
 or residue. 
 
 Wood alcohol is much less desirable as a household 
 fuel than ethyl alcohol, and is much less efficient. The 
 number of calories produced by the burning of wood 
 alcohol is only about half of that which the burning of 
 grain alcohol produces. The two alcohols are also very 
 different in taste, odor, and in the effect upon one who 
 may drink them. Ethyl alcohol is the alcohol of wines 
 and other intoxicating drinks. Its odor is not unpleasant 
 and its taste is slightly biting. On the other hand, 
 methyl alcohol has an odor and taste so very offensive 
 that it is undrinkable except by one whose taste has 
 long been impaired by drunkenness, or otherwise ; and 
 when it is taken into the stomach it is a virulent poison. 
 
 Both of the alcohols are composed of the same 
 chemical elements, carbon, hydrogen, and oxygen, their 
 differences being due to the different proportions of 
 those elements in each, and also to the difference in the 
 manner of their combination. The manner of origin 
 of these two alcohols is also very different. So far as 
 is now known, the only method of producing ethyl 
 alcohol is by the fermentation of some form of sugar, 
 and its distillation from the substance so fermented. 
 The reason why this alcohol is so often spoken of as 
 grain alcohol is that in our country it is largely dis- 
 tilled from Indian corn, or some other grain the starch 
 
HOUSEHOLD FUELS 71 
 
 of which has been changed to some form of sugar. 
 Molasses obtained in the process of the making of cane 
 sugar has been much used for the production of ethyl 
 alcohol, and it may be produced by fermenting any 
 substance which contains starch or any kind of sugar. 
 
 Methyl alcohol is known by several different names, 
 the best known of which is wood alcohol ; but it is often 
 called wood spirit and pyroxylic spirit. This alcohol is 
 not obtained by fermentation, but by a process known 
 as the destructive distillation of wood. Most of the 
 methyl alcohol sold in the markets is obtained as one 
 of the by-products of the wood which is used in the 
 improved kilns for making charcoal, as was described 
 in a preceding chapter. 
 
 Although the alcohols are exceedingly volatile and 
 combustible, they do not, properly speaking, explode, 
 as do the lighter mineral oils. They may, however, 
 cause serious damage if spilled on clothing near a fire, 
 because of their ready combustion. Still, they may 
 always be burned safely by careful persons in the well- 
 known small alcohol lamps and chafing dishes and in 
 the modern alcohol stoves. There have recently come 
 into use stoves for the burning of alcohol which are 
 large enough to hold utensils of moderate size. In these 
 stoves the alcohol is vaporized before it reaches the 
 burners, the effect of which is to produce flames similar 
 to those of the blue-flame gas burner. 
 
 The extremely high tax which has been for so many 
 years placed on ethyl alcohol by the United States 
 government has had the effect of almost prohibiting its 
 use as a fuel. The increasing demand for fuel, and the 
 
72 HOUSEHOLD FUELS 
 
 fact that a large number of farm products which have 
 hitherto been thrown away may be made to yield alcohol, 
 has induced the government to reduce greatly the tax 
 on alcohol provided it shall be "denatured." The object 
 of denaturing alcohol, that is, the changing of it from 
 its natural condition, is to render it undrinkable and 
 at the same time not to impair its value as a fuel or 
 its usual use in the industrial arts. What substances 
 shall be added to the alcohol, and in what proportions, 
 is prescribed by law. The substances must be so offen- 
 sive to the taste that it will make the mixture undrinkable. 
 The chief substance thus prescribed is wood alcohol. In 
 addition there may be oil of turpentine, benzine, carbolic 
 acid, and many other substances. A list of these sub- 
 stances is given on page 8 of Farmer's Bulletin 268, 
 published by the United States Department of 
 Agriculture. 
 
CHAPTER VIII 
 GASEOUS FUELS 
 
 '"T"*HE term gas is applied to those substances which 
 -*- are invisible and impalpable, and which may be 
 composed of a single chemical element, or a compound 
 of elements, or they may be a mere mechanical mix- 
 ture of other gases. They are more or less in a condition 
 similar to that of air, which is itself composed of gases. 
 Some of them are incombustible, some- support combus- 
 tion, and some are themselves combustible. It is only 
 the last named class with which we are now concerned. 
 It is shown in the preceding chapter that all fuels 
 which burn only with flame must be reduced to a gaseous 
 condition before ignition, and that the semi-solid and 
 liquid fuels are in that case really condensed gaseous 
 fuels. The wick in use for both of those kinds of fuel 
 not only localizes the flame, but serves as a vehicle to 
 convey the fuel in its liquid state uniformly and in suit- 
 able quantity to the base of the flame. It is here that 
 the service of the wick ends, and here that those con- 
 densed fuels become identical with the gaseous fuels. 
 Illuminating gas being already in that reduced condition 
 needs no such preparation, and is burned from small 
 openings in those familiar appliances called burners, 
 through which it is made to pass by pressure within 
 the gas pipes. All the illuminating gases will ignite 
 instantly at the touch of flame or of an electric spark, 
 
 73 
 
74 HOUSEHOLD FUELS 
 
 as it issues from the burner, and it is instantly extin- 
 guished by shutting off the flow of gas. These familiar 
 facts are repeated here as a basis for references that 
 are to be made in following paragraphs. 
 
 It was not until near the close of the eighteenth 
 century that it was demonstrated that gas from coal 
 might be used as a fuel for lighting, and it was many 
 years afterward that its use as a heating fuel was recog- 
 nized. The first illuminating gas was made from bitu- 
 minous coal, but other gaseous compounds and mixtures 
 have since been introduced which have largely super- 
 ceded coal gas in use for both lighting and heating. 
 The artificial gases which are now used as household 
 fuels are known as coal gas, water gas, gasoline gas 
 (sometimes called air gas), and acetylene gas, respec- 
 tively. Besides these, great quantities of natural gas 
 have been discovered in some parts of our country by 
 boring in the earth. All these gases are spoken of col- 
 lectively as illuminating gases, although they are largely 
 used for heating purposes also. 
 
 Pure coal gas is a pure hydrocarbon, and therefore 
 a perfect fuel. It is the most efficient and unobjection- 
 able of all the gaseous fuels for heating and lighting. 
 It is claimed by some gas experts that a mixture of coal 
 gas and water gas may be made which is superior to 
 any coal gas alone. This assertion has apparently never 
 been proved to the satisfaction of consumers. Coal gas 
 may be made from any coal which contains a large pro- 
 portion of hydrogen. The best for this purpose is 
 unquestionably bituminous coal, because it is rich in 
 hydrogen and free, or easily freed, from all deleterious 
 
HOUSEHOLD FUELS 75 
 
 substances. The best of heating coals, anthracite, is 
 excluded in this statement because of its lack of 
 hydrogen. 
 
 A part of the process of making coal gas has been 
 incidentally described in Chapter IV as a part of the 
 process of coke making, but it is repeated here to give a 
 connected account of gas making. In the process of 
 making coal gas, the coal is placed in kind of long 
 ovens, called retorts, which have an opening only at the 
 front end, through which the coal is filled. Sometimes 
 these retorts are made of iron and sometimes of a 
 variety of fire-clay, and are set in masonry, with a fire- 
 place under each. A pipe is attached to the upper side 
 of each retort to lead off the gas as it escapes from the 
 coal within. After the coal is introduced, the front 
 opening of each retort is tightly closed and sealed. The 
 retorts are then submitted to a high heat, which liberates 
 the gas and other volatile products from the coal, all of 
 which escape from the retorts by the exit pipes. The 
 gas is immediately passed through a process of purifica- 
 tion, while the by-products, which are more or less 
 valuable, are saved. The purified gas is conducted by 
 pipes to a very large receptacle, called a gas holder or 
 gasometer, which has much the appearance of a huge 
 inverted cup. 
 
 This huge gasometer, floating, full of gas, upon an 
 open cistern full of water, is connected to pipes which 
 pass under ground to the places where the gas is con- 
 sumed. It is the weight of the floating gasometer that 
 furnishes the force to distribute the gas in the under- 
 ground pipes. The gas made and distributed in this way 
 
76 HOUSEHOLD FUELS 
 
 consists of hydrogen from the coal, together with a part 
 of its carbon. The residue left in the retorts is coke, 
 which has already been described under the head of solid 
 fuels. 
 
 Water Gas. This gas is so called because a portion 
 of both the hydrogen and oxygen of which it is com- 
 posed is obtained by decomposing water. Water, in 
 the condition of superheated steam, is passed over a 
 mass of glowing anthracite and is decomposed by the 
 intense heat of the burning coal. The hydrogen of 
 the water is set free and the oxygen of the water unites 
 with carbon from the anthracite, forming the gas, carbon 
 monoxide. The freed hydrogen and the carbon monox- 
 ide together form the mixture known as water gas. 
 This gas mixture, although combustible, produces only 
 a slight flame. Burning hydrogen gives little light 
 but much heat, and the mixture of these two gases 
 alone does not produce a serviceable gas either for 
 heating or lighting. Therefore, to make this mixture 
 serviceable it is necessary to enrich it. The enrichment 
 process was originally accomplished by passing the mix- 
 ture of hydrogen and carbon monoxide immediately 
 to a receiver, where more of both hydrogen and carbon 
 were added to it. These additional elements were sup- 
 plied by petroleum, and the mixture of water gas and 
 petroleum was subjected to great heat, which changed 
 the liquid petroleum to a gaseous condition which is so 
 firmly fixed by the process that it cannot return to its 
 liquid condition on cooling. Water gas so enriched 
 is therefore a complex mixture of hydrogen, carbon 
 monoxide, and petroleum vapor. 
 
HOUSEHOLD FUELS 77 
 
 Recently, a process has been devised by which the 
 petroleum is added to the current of superheated steam 
 before mentioned, so that the enrichment is effected 
 over the glowing anthracite when the water gas is made. 
 Therefore it is not necessary by this new method to 
 pass the gas to a receiver, and it is sent at once to the 
 gas holder for service to consumers. 
 
 Even when water gas has been enriched over the 
 glowing anthracite, as has just been described, it is not 
 sufficiently rich in either carbon or hydrogen to make a 
 good gas for either heating or illuminating purposes. 
 It has, however, often been furnished by gas companies 
 to consumers without further improvement. Still, most 
 of the companies which furnish water gas now not only 
 enrich it with petroleum while making it, but they add 
 to it a considerable proportion of good coal gas. This 
 latter addition greatly improves the quality of the gas, 
 which, it is claimed by some experts, is then equal to 
 the best coal gas in both heating and lighting qualities. 
 It should, however, be remembered that even the best of 
 this compound gas contains a large proportion of the 
 poisonous carbon monoxide. 
 
 Gasoline Gas. This gas is always made on a 
 smaller scale than that which is furnished by gas com- 
 panies, and is usually made in private plants for rural 
 dwellings and institutions where large supplies from a 
 gas -company are not available. It is a mixture of the 
 vapor of gasoline with air, for which reason it was 
 formerly called air gas. A large tank of gasoline is 
 buried in the ground, the law in such cases generally 
 requiring that it shall not be less than thirty feet from 
 
78 HOUSEHOLD FUELS 
 
 the buildings, and into this tank of gasoline air is forced 
 by means of a pump, the structure of which is so simple 
 that a child can operate it. 
 
 The air thus pumped into the gasoline forces from 
 it the gaseous vapors into which the volatile liquid 
 readily separates, and these vapors and the air together 
 escape through pipes from the upper part of the tank 
 to the mixing chamber. This mixing chamber, or mixer, 
 as it is sometimes called, is nearer the buildings than 
 the tank is allowed to be, and here the gas is mixed with 
 more air, which is forced into the mixer by the same 
 pump that forces air into the tank of gasoline'. From 
 the mixer, the gas which has been derived from the 
 gasoline is mixed with so much air that it cannot return 
 to its liquid condition, is conducted by pipes into the 
 building, where it is used for both lighting and heating 
 purposes. As gasoline gas is now prepared it makes 
 an excellent household fuel and does not contain carbon 
 monoxide, which is so large a constituent of water gas. 
 
 Acetylene Gas. Besides the gases already men- 
 tioned, there is another artificial gas, acetylene, which, 
 like the gasoline gas, is produced only by private plants 
 for country or village homes and separate institutions. 
 Many plants for making this gas have lately been in- 
 stalled. The cost of the plant is not very high, the 
 method of producing the gas is simple, and the gas 
 gives a brilliant light when burning. Calcium carbide, 
 from which acetylene gas is obtained, is now a mer- 
 chantable article. Pieces of it are dropped automatically 
 into water which is contained in a suitable receptacle. 
 The gas, which is a pure hydrocarbon, immediately 
 
HOUSEHOLD FUELS 79 
 
 results by chemical decomposition and is ready for use. 
 It is conveyed from the generating apparatus by ordi- 
 nary gas pipes into the house, and burned as is ordinary 
 gas. This gas, however, requires specially constructed 
 burners. 
 
 Many objections have been urged against the use of 
 acetylene gas in the household, notwithstanding the 
 excellence of its light. It is certainly violently explosive, 
 or may become so if not used with great care. It has 
 the reputation of being virulently poisonous if inhaled, 
 but manufacturers of acetylene supplies deny this. The 
 expense of running an acetylene plant is greater than 
 is that for any other gas plant, but the plant itself is 
 not proportionately expensive. 
 
 The housekeeper's experience with acetylene gas 
 may be gained under varying conditions. She may be 
 delighted with the brilliant flame which this gas pro- 
 duces as it comes from the pure and clean solution of 
 calcium carbide, or she may have a very different experi- 
 ence, even if the danger of poison and explosion has 
 been overestimated. That is, she is likely to have an 
 unpleasant experience with acetylene gas in its crude 
 state w 7 hen the flame of the burner of her range "flares 
 back" with a lurid, ill-smelling, and angry flame. That 
 flame is not the flame of common gas that the range 
 is supplied with, but is the result of a vitiated condition 
 of that gas, and consists of a mixture of acetylene and 
 carbon monoxide, both of which are formed at the air 
 inlet of the burner by the incomplete combustion of the 
 gas in use. There can be no question of the poisonous 
 quality of the carbon monoxide, and that of the crude 
 acetylene is not less so. 
 
8O HOUSEHOLD FUELS 
 
 Natural Gas. This gas, which is a hydrocarbon, 
 occurs naturally in the earth, and is obtained in sufficient 
 quantity for practical use by borings like those which 
 are made for mineral oil and artesian waters. It is a 
 valuable fuel for heating purposes, but it does not give 
 quite so brilliant a light as does coal gas. It is abundant 
 in some regions, but in the greater part of our country 
 it is not known to exist. From some of the well-pipes 
 the gas rushes with great force, but the force of the 
 flow perceptibly diminishes in all of them with their 
 use. 
 
 More or less gas of a similar kind escapes from 
 petroleum as it gushes from the wells, and such gas 
 sometimes issues spontaneously in small quantities from 
 fissures in the rocks, or from the earth. It is gas of 
 this kind that causes explosions in coal mines, and is 
 called fire-damp by the miners. 
 
 In those regions where natural gas is obtained it is 
 used successfully for both light and heat, not only in the 
 industrial arts, but in the household. As might have 
 been expected, there are sure indications of a gradual 
 failure of the supply of natural gas, and in many places 
 the supply has already given out. This failure has 
 occurred, not only in the less important borings, but 
 in some of those from which the supply was formerly 
 abundant. Geologists generally believe that the origin 
 of natural gas was similar to that of the mineral oils, 
 that is, that it has resulted from some of the great 
 accumulations of vegetable matter that are known to 
 have existed; but the actual proof of such origin has 
 not yet been fully determined. 
 
CHAPTER IX 
 ECONOMY OF FUELS 
 
 THIS chapter is devoted mainly to remarks of a 
 supplementary character upon subjects which have 
 been discussed or referred to on the preceding pages, 
 besides others in which the practical housekeeper is 
 especially interested. None of those subjects is of more 
 importance in the economy of the household, especially 
 in the rural districts, than is that which pertains to the 
 liability to injury of wood fuels, and the necessity of 
 their careful preservation. If these remarks appear 
 to be censorious in some respects, it is because of the 
 prevalent inexcusable wastefulness of wood fuel. That 
 wastefulness is so great as to justify an estimate of a 
 loss of fifty per cent in the possible heating power of 
 the marketed wood fuel of our country. To these 
 remarks are added some statements concerning methods 
 of measurement of fuels, and cautions concerning the 
 use of some of the others. 
 
 Although wood is so extensively used as a household 
 fuel, and custom as to the manner of its measurement 
 for sale is nominally uniform throughout the land, no 
 other kind of fuel, and perhaps no other kind of mer- 
 chandise, is bought and sold with so little regard to its 
 quantity and quality. A legal cord of wood contains 
 128 cubic feet, and municipal regulations usually require 
 that the sticks shall be of the full length of four feet, 
 
 81 
 
82 HOUSEHOLD FUELS 
 
 in addition to one-half of the sloping cut at each end. 
 Those regulations also require that the sticks of wood 
 shall be corded with as little space between them as 
 practicable. 
 
 By some dealers these regulations are habitually 
 disregarded, and, although many formally comply with 
 the law, full legal measurement is often exceptional. In 
 a not unusual case of this kind a quantity of wood 
 is sawed into very short pieces, put into a cart, and 
 delivered by dumping, with a bill for half a cord. If 
 the purchaser should have a fuel bin four feet long, 
 four feet high, and four feet wide, the exact dimensions 
 of half a cord, and expect that load of wood to fill it 
 if closely packed, it is superfluous to say that he will be 
 disappointed. If the half cord of \vood should be pur- 
 chased as four- foot cord wood, it will not be a hard task 
 to test the measure with a foot rule or a yard stick. It 
 will doubtless appear that the manner of packing of the 
 purchaser will differ greatly from that of the seller. 
 
 But the loss to which the purchaser of wood fuel 
 is subjected is far greater with reference to quality 
 than to quantity. Moreover, much of the loss of 
 quality is occasioned, not by intentional deception, but 
 by ignorant neglect and want of that practical sentiment 
 which bestows proper regard upon everything that has 
 borne the impress of life. 
 
 There can be no doubt that everything that man 
 has ever used for fuel had its origin in some form of 
 life. The range of fuel origin in extinct forms extends 
 from anthracite, on the one hand, to natural gas, that 
 came from unknown vegetation, on the other. Alan has 
 
HOUSEHOLD FUELS 83 
 
 not only been ready to use the remains of extinct forms 
 of life for fuel, but to destroy that of present forms. It 
 is true that he has innocently obtained large quantities 
 of fats and oils from vegetable fruits and nuts, but 
 when he has wanted animal oils and fats he has sent 
 out thousands of his fellowmen for the slaughter of the 
 whale and seal, and their victims have numbered millions. 
 
 After making such havoc with animal life it is not 
 to be expected that he should show any regard for a 
 tree. If he wants firewood, he kills a tree to obtain it. 
 He does not then give it the care which a butcher gives 
 to the body of an animal which he kills, but ruthlessly 
 cuts its graceful trunk in pieces and scatters them upon 
 the ground, where they are left to decay and to the 
 ravages of burrowing grubs. If he is a dweller where 
 trees are plentiful, and desires to cultivate the ground 
 upon which they grow, he girdles them. That is, he 
 kills them by cutting a continuous wound around the 
 trunks with his ax. The trees slowly die, and at his 
 leisure he cuts them up and brings the damaged, worm- 
 eaten wood to the fuel markets. The full extent and 
 character of such damage to firewood can be properly 
 appreciated only by examination of the structure and 
 manner of growth of trees. 
 
 The growing tree constantly produces fresh organic 
 substance within its tissues, and it is this substance in 
 the wood that is peculiarly subject to decay. The part 
 of wood which becomes charcoal, or nearly pure carbon, 
 is not subject to organic decay when separated by heat 
 from the organic substances referred to. That fresh 
 organic substance consists of the protoplasmic contents 
 
84 HOUSEHOLD FUELS 
 
 of the living cells, the delicate walls of which become 
 wood by hardening, thickening, and elongation. The 
 growing cells receive the necessary moisture from the 
 food-sap which the tree absorbs from the earth by its 
 roots. That moisture is constantly present in the grow- 
 ing tree, and remains after it is dead as an aid to 
 decomposition of the delicate cells. The only practicable 
 way to prevent that decay in wood without impairing 
 its fuel value is by thoroughly drying it as soon as 
 possible after the trees are felled, and keeping it dry 
 until it is to be burned. 
 
 As one examines the woody structure of the square- 
 cut end of the woodman's log, especially after it has 
 lain a few weeks upon the ground, it is evident that 
 some portions are liable to decay sooner than others. 
 The inner portion of the log, comprising the greater part 
 of its bulk, and commonly called the heartwood, is 
 denser and darker in color than is the narrower portion, 
 having a similar woody texture, which lies immediately 
 outside of it. That outer layer is commonly called sap- 
 wood, but botanists call it alburnum. The contrast in 
 color between the heartwood and sapwood is very great 
 in some trees. In the juniper, or, as it is commonly 
 called, red cedar, the heartwood is red and the sapwood 
 is white. In the black walnut the heartwood is brown 
 and the sapwood nearly white. But the difference 
 between the heartwood and sapwood in which we are 
 now specially concerned is shown by the greater liability 
 of the latter to decay. 
 
 There is between the sapwood and the bark a very 
 thin layer of cells which is called the cambium layer, 
 
HOUSEHOLD FUELS 85 
 
 and which is still more subject to decay than is the sap 
 wood. In the living tree these cells are minute spherical 
 or polygonal, living, and constantly increasing vegetable 
 cells. When first formed they are extremely delicate, 
 but their so-called cell walls soon elongate, thicken, and 
 take on a woody texture. They therefore become wood 
 cells on the inner, and bark cells on the outer side of the 
 cambium layer, their former places in the cambium layer 
 being constantly filled by new cells as long as the tree 
 increases in growth. When the tree is cut down it is 
 killed, and no more cells form in any part of it. Unless 
 the wood is then very thoroughly dried, the protoplasm 
 which its cells contain begins at once to decay, and the 
 decay of the protoplasm soon involves the woody tissue, 
 especially that of the sap wood and the delicate cells of 
 the cambium layer. The latter cells are the first to yield. 
 The outer bark and heartwood resist decay longest 
 because there is very little protoplasm left in their 
 thickened and hardened cells. 
 
 When the wood of newly felled trees is left exposed 
 to the weather or stored in a damp place, the effect of 
 the decay is first noticeable by the loosening and cleav- 
 ing off of the bark. This is because the new cells 
 forming the cambium layer have completely decayed, 
 and nothing remains to hold the bark from falling away 
 from the wood. This is the first stage of firewood decay* 
 which is practically identical with the decay of all fresh 
 vegetable substances. Cut into the sapwood of a stick 
 from which the bark has been thus loosened and it will 
 be seen to have a discolored appearance, and a little 
 later its rotten condition will be unmistakable. This is 
 the second stage of decay. 
 
86 HOUSEHOLD FUELS 
 
 Often not only logs and sticks in which decay has 
 plainly begun, but others which are apparently sound 
 may be found to be completely riddled by boring insect 
 grubs which have developed from eggs that were de- 
 posited on the outer surface of the bark after the tree 
 was felled. Immediately upon being hatched all wood 
 grubs burrow into the wood in search of remains of the 
 protoplasmic contents of the wood cells, which furnish 
 their necessary food. They have a short, worm-like body 
 and a large head armed with strong, horny jaws. With 
 those jaws the grub tears up the wood to a condition 
 resembling fine sawdust, and swallows every particle of 
 it. The proteid nutriment is absorbed by the intestinal 
 canal from the sawdust-like material as it passes through. 
 The refuse material is continuously evacuated and packed 
 so firmly in the burrow behind the grub, as it goes for-' 
 ward, that the packed material closely resembles the 
 adjacent decaying wood. 
 
 The foregoing statements of the effects of proto- 
 plasmic decay of wood fuel and of the habits of boring 
 grubs in partially decayed wood have been selected as 
 practical illustrations of the great necessity of carefully 
 drying and housing the wood immediately after the trees 
 are felled. Extreme dryness is the best possible safe- 
 guard against most forms of rot and against some of 
 the insect depredations, but unfortunately every case 
 of the latter kind cannot be met so simply. 
 
 For example, the hickory borer will attack the wood 
 of that tree only after the tree is killed, and it is so per- 
 sistent in its attacks then that it will sometimes follow 
 that wood into the woodhouse, refusing all other kinds. 
 
HOUSEHOLD FUELS 8/ 
 
 The grub of that insect hatches out in the spring, and 
 therefore if the hickory trees are felled in late autumn 
 or early winter the wood will probably have dried suffi- 
 ciently to resist the attacks of the grubs when they 
 appear. The mature insect is one of the long-horned 
 (longicorn) beetles, and should be killed at sight. It is 
 desirable to know the habits of other insects in their 
 relation to wood fuel, but only the foregoing statement 
 is selected, because hickory is the best firewood that our 
 country affords, and the hickory borer is one of the most 
 persistent of its kind. 
 
 It should not be forgotten that the drying out of the 
 original sap of wood fuel before it is used is absolutely 
 essential, for wood is not suitable for fuel until that 
 original moisture has been removed. The drying out 
 of the sap and all accessory moisture is not only essen- 
 tial in preserving the wood from rot, but in preserving 
 its heating power. Water in the fuel always changes 
 to superheated steam in the fire, and carries off and 
 wastes a large proportion of the heat which the fuel 
 generates. 
 
 Measurement of Fuels. All mineral coal is sold 
 by weight, the unit being the ton. Municipal regulation 
 in certain parts of our country requires 2,240 pounds to 
 the ton, but in many parts of it only 2,000 pounds to the 
 ton are required. They are called the long ton and 
 the short ton, respectively. The relation of each of these 
 tons to measured space in fuel bins may be readily 
 learned, and such bins should be well protected, even 
 for mineral coal. 
 
 Wood is sold by the cord, of 128 cubic feet. By the 
 
88 
 
 HOUSEHOLD FUELS 
 
 shortening of the length of the sticks and loosely pack- 
 ing them a difference of fifteen or twenty per cent may 
 be made in favor of the seller. 
 
 Charcoal and coke are sold by the bushel. Although 
 both of these fuels are hardly subject to decay, they 
 absorb moisture so readily that they need special care 
 in housing. 
 
 All the semi-solid fuels are sold by the pound. They 
 are comparatively so exempt from liability to decay that 
 only ordinary care is needed to preserve them. 
 
 The liquid fuels are sold by measure, the unit being 
 the Winchester, or wine, gallon, containing 231 cubic 
 inches. As the cans in which dealers serve the mineral 
 oils to purchasers are rectangular in shape, it is easy 
 to estimate their capacity. 
 
 The gaseous fuels are served to consumers by the 
 companies measured by a meter, the unit being 1,000 
 cubic feet. The meter is locked and controlled by the 
 company, but three small dials on the face of the meter 
 are Visible to every one. These dials are used by the 
 company in rendering their bills for gas to consumers, 
 as indicating the amount of gas consumed. 
 
 In the purchase of the solid and semi-solid fuels 
 there is opportunity for the housekeeper to use her 
 judgment as to quality and quantity of the articles she 
 purchases. In the case of the liquid fuels, however, 
 she cannot so easily detect the adulterations and dilutions 
 which have been practiced. Fortunately, dilutions of 
 kerosene are not now to be feared, but those of the 
 alcohols may occur in any degree that a dishonest dealer 
 may venture to practice. In the case of gas from the 
 
HOUSEHOLD FUELS 89 
 
 public plant, she must, as a rule, abide by the custom 
 of the company as to the quality, quantity, and pressure 
 of service. 
 
 Injurious Fuels. The fact that serious injury to 
 persons and property may occur from contact with fire 
 is too well known to need mention except in connection 
 with cases of special liability to injury from the use of 
 certain fuels. There are three different sources of danger 
 besides that of common fire to which the household 
 is exposed in the use of its fuel, namely, that of suffo- 
 cation, poison by inhalation, and explosion. 
 
 All the kinds of gas which are used for lighting or 
 heating are liable to explode, often with great violence, 
 upon escaping from the pipes and mingling with the air. 
 All kinds of those gases will produce suffocation to the 
 person breathing them in considerable quantity, and at 
 least a part of them will also act as a virulent and some- 
 times fatal poison when taken into the lungs. Fortu- 
 nately, poisoning by ordinary contact with any household 
 fuel is not to be feared, and with the exception of w^Dod 
 alcohol no fuel substance has the reputation of being 
 poisonous in the stomach. One will readily see that both 
 the wood and ethyl alcohol ought to be kept beyond the 
 reach of those who may possibly misuse them. 
 
 Safety to the household requires constant watchful- 
 ness against gas leakage of all kinds, especially as regards 
 its explosive qualities. Leakage is best detected by the 
 odor of the gas, which is usually strong and unmistak- 
 able. Upon perceiving the odor, the room or suspected 
 place must at once be fully ventilated by opening the 
 doors and windows. On no account must a lighted 
 
9O HOUSEHOLD FUELS 
 
 match or other fire be admitted until the ventilation is 
 complete. The leak may then be sought by the sense 
 of smell, and if the odor is strong the escape must be 
 stopped at once by turning the stopcock of the house 
 supply pipe, which is to be found at one side of the 
 meter. If the odor is slight, the leak may be sought by 
 holding a lighted match to the suspected place of issue. 
 If the leak should be there, a jet of flame will issue of a 
 size comparable with the aperture. No leak, however 
 small, must be neglected. Danger always lurks with 
 escaping gas, and safety lies in complete repair. 
 
 The flare-back flame which so often results from the 
 lighting by a match of the blue-flame gas burners, 
 whether used for lighting, heating, or cooking, should 
 be immediately stopped by turning off the gas and re- 
 lighting it as often as is necessary to obtain a pure flame. 
 Because this flame consists of a mixture of carbon 
 monoxide and crude acetylene gas, the necessity of 
 cutting off its flow is quite apparent. 
 
 The Fireless Cooker. An effective method of 
 cooking certain kinds of food is by simmering for a 
 long time over a fire S3 small as to keep the food at 
 a temperature just below the boiling point of water. 
 A method of similar cooking may be conveniently accom- 
 plished by a device which is popularly known as "the 
 fireless cooker," which is mentioned here because of its 
 present increasing popularity and usefulness. It also 
 serves as an illustration of the fact that a very large 
 proportion of the heat which is produced in all of our 
 ordinary methods of cooking is utterly wasted. The 
 present rate of diminution of the world's supply of fuel 
 makes this subject one of increasing importance. 
 
HOUSEHOLD FUELS 9 1 
 
 This device is cylindrical or rectangular in shape, 
 and may differ much in details of construction. The 
 most effective kind consists of a double box of either 
 wood or metal, the larger part including the smaller, 
 so that there shall be a considerable space between them, 
 to be filled with asbestos fiber, or some other non- 
 conductor of heat. Still, the box is often made without 
 the interspace, but of material which is known to 
 resist the escape of heat. Usually the top or one side 
 of the box is removable or hinged as a door, and the 
 joint between it and the box is secured by some non- 
 conducting material. Whatever may be the modifica- 
 tions of structure, it is imperative that provision shall 
 be made for the retention of heat within the box. 
 
 The smaller cookers hold only one or two vessels 
 of food, but the larger kind may be as large as a small 
 traveling trunk and may hold several food vessels, 
 packed upon one another if necessary, for which reason 
 the covers should be flat. To increase the heat within 
 the box, heated plates of cast iron may be used to over- 
 lay the covers. The food, each kind in a separate vessel, 
 is heated to boiling over a common fire, where the cast 
 iron plates are also heated, and all are placed in the box, 
 previously warmed before the fire. The closed box is 
 then put in a protected place for several hours, when 
 the food will have become thoroughly cooked and remain 
 still hot. 
 
 The cooking of the food by this method is effected 
 wholly by the preliminary heating that is given it over 
 the fire, that heat being retained in action upon the food, 
 and its escape prevented, by the non-conducting material. 
 
9 2 HOUSEHOLD FUELS 
 
 While these cookers are a valuable addition to domestic 
 needs, it is true that they are adapted to only a part of 
 the requirements of the household for food variety. 
 Still, an ingenious housekeeper may readily adapt one 
 of these cookers to the preparation of a good variety and 
 generous quantities of nourishing and acceptable food, 
 with an important reduction of her own labor and of 
 expense for fuel. 
 
CHAPTER X 
 ELECTRICITY 
 
 A LTHOUGH the object of this essay is only to 
 * * discuss fuel substances, so much advance has 
 been made in the substitution of electricity for house- 
 hold fuels that brief mention of it is here appropriate. 
 All recent text-books of physics describe what is now 
 known of the character and action of electricity, and the 
 literature of that subject is abundant. It is sufficient, 
 therefore, to say here that electricity is not a substance, 
 but a force, or a form of energy, that under certain 
 conditions flows as a permeating, instantaneous current 
 in certain directions through various substances, but not 
 through others. The former are called conductors and 
 the latter non-conductors of electricity. The current 
 flows with much greater force through some conductors, 
 copper and iron, for example, than through others. 
 Glass and India rubber are among the most complete 
 non-conductors. Many substances, among which are 
 carbon and various metals, are tardy conductors of elec- 
 tricity, and when inserted by attachment between the 
 severed ends of a good conducting wire they resist the 
 current. It is this resistance that causes the heat or 
 incandescence, or both, in the resisting material. This 
 heat is sufficiently intense for all household purposes, 
 and the incandescence gives a light of great and agree- 
 able brilliancy. 
 
 93 
 
94 HOUSEHOLD FUELS 
 
 Materials of different degrees of conductivity and 
 resistance are used in the construction of electric light- 
 ing, heating, and cooking appliances, a large variety of 
 which are now offered for sale as ordinary merchandise 
 in all of our principal cities. The electric light bulb, 
 with its long folded carbon filament, has become a 
 familiar object, but the use of the heating and cooking 
 appliances does not expose them so much to public 
 observation. The heating devices take various forms of 
 radiators, and those which are constructed for cooking 
 are similar in general form and practical use to those 
 in which the gaseous fuels are burned, but of course 
 the details of their construction are very different. 
 
 The advantages of the household use of electricity 
 are its capacity for producing abundant light and heat 
 and its entire cleanliness and freedom from objection- 
 able odors. There is no escape of gases or of products 
 of combustion into the air of the room in which it is 
 used, as is always the case to a greater or less extent 
 when liquid or gaseous fuels are burned. The disadvan- 
 tages of its domestic use are its present greater cost 
 than that of fuels, and the necessity of establishing a 
 comparatively large plant to insure a sufficiently large 
 and constant supply of light and heat. Electricity is 
 therefore not at present practically available as a full 
 substitute for fuels except in cities and the larger vil- 
 lages, or near waterfalls or other natural sources of 
 mechanical power. Recourse to such sources of power 
 is necessary because all the electricity which has been 
 brought under human control is produced by its artificial 
 transformation from other forms of energy. Indeed, 
 
HOUSEHOLD FUELS 95 
 
 most of the electricity which is now in use is generated 
 by power which has been produced by the burning of 
 fuels. 
 
INDEX 
 
 Acetylene Gas, 78 
 
 Air Gas, 77 
 
 Alcohol, Grain (Ethyl), 70 
 
 Wood (Methyl), 48, 70 
 Angiosperms, 41 
 Anthracite, 30 
 Ashes, Wood, 12 
 
 Bituminous Coal, 31 
 Brimstone Match, 17 
 
 Camphene, 64 
 Candle Flame, 20 
 
 Making, 54 
 
 Tallow, 53 
 Cannel Coal, 34 
 Carbon, 7, 9 
 Charcoal, 47 
 
 Kilns, 48 
 Chemical Elements, 5 
 
 Reaction, 6 
 
 Classification of Fuels, 2 
 Coal, Bituminous, 31 
 
 Gas, 74 
 
 Non-Bituminous, 34 
 
 Oil, 65, 69 
 
 Semi-Bituminous, 33 
 Coke, 32 
 Combustion of Fuels, 10 
 
 Products of, 1 1 
 Conifers, 45 
 
 Electiicity, 93 
 Elements, Chemical, 5 
 Fuel, 6 
 
 Accessory, 8 
 
 Fats, 52 
 
 Fireless Cooker, 90 
 
 Flame, Candle, 20 
 
 Combustion, 20 
 
 Flare-Back, 90 
 
 Gas, 23 
 
 Lamp, 23 
 
 Flint, 1 6 
 
 Fuel Elements, 6 
 
 Accessory, 8 
 Fuels, Classification of, 2 
 
 Composition of, 5 
 
 Economy of, 81 
 
 Gaseous, 73 
 
 Injurious, 89 
 
 Liquid, 60 
 
 Measurement of, 87 
 
 Semi-Solid, 51 
 
 Solid, 26 
 
 Wood, 37 
 
 Gas, Acetylene, 78 
 
 Air, 77 
 
 Coal, 74 
 
 Flame of, 23 
 
 Gasoline, 77 
 
 Natural, 80 
 
 Water, 76 
 Gaseous Fuels, 73 
 Gasoline, 68 
 
 Gas, 77 
 
 Grain Alcohol, 70 
 Grubs, Hickory, 86 
 
 Wood-Boring, 86 
 
 Hydrogen, 8, 9 
 
 Ignition, 14 
 Incandescent Light, 25 
 Injurious Fuels, 89 
 
 Kerosene, 66 
 Tests of, 67 
 Kindling, 15 
 
 Lard Lamps, 53 
 
 Oil, 62 
 Lignite, 35 
 Liquid Fuels, 60 
 
 Mantle Light, 25 
 
 96 
 
HOUSEHOLD FUELS 
 
 97 
 
 Matches, Brimstone, 17 
 Friction, 18 
 
 Safety, 19 
 
 Measurement of Fuels, 87 
 Mineral Fuels, 27 
 
 Oils, Grades of, 65 
 
 Natural Gas, 80 
 Nitrogen, 8 
 
 Oil, Coal, 65, 69 
 
 Lard, 62 
 
 Olive, 6 1 
 
 Palm, 61 
 
 of Turpentine, 64 
 
 Whale, 62 
 Oxidation, 10 
 Oxygen, 10 
 
 Palmitin, 57 
 Paraffin, 58, 65 
 Peat, 26, 35 
 Petroleum, 65, 69 
 
 Resin, 50, 58 
 
 Safety Matches, 19 
 Semi-Solid Fuels, 51 
 Solid Fuels, 26 
 Spermaceti, 57 
 Stearin, 57 
 Sun Glass, 16 
 
 Tallow Candles, 53 
 Tar Kiln, 50 
 Tinder, 17 
 
 Unusual Fuels, 46 
 Vaseline, 65 
 
 Water Gas, 76 
 
 Wax, 55 
 
 Wood Alcohol, 48, 70 
 
 Ashes, 12 
 
 Fuels, 37 
 
 Grubs, 86 
 
 Kinds of, 42 
 
 Rotting of, 85 
 
 Structure of, 84 
 
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