The Locomotive Of Today

58 The Boiler : Combustion. holeXdræd tO “ eXt6nt by the further °Pen!n? °f the fire- the explanation ali boriS \°f combustlon> it is understood that different substnnr1S1 ° ^n-v means at our command into tinSed bv thA possesfsinx ^’stinct properties, are dis- thoS which "a?% S™ple bodies Or elements; and _ n , Ch are *ormed of two or more elements combined arp called compound bodies. These elements will onlv combine emeni can be reduced to is called an atom, and the weiø-ht of this small portion is called the atomic weight of thZ sub- stance. In companson with hydrogen, which5 is taken as t °f the ^-coäponents of’ord^X U’ t b°n I2’ oxy§"en x6, nitrogen 14, and sulnhur t.? When two or more atoms of elements combine tog-ether and orm a compound body, the smallest division of it is called i S™.0 ’ an<i thlS CannOt be further reduæd “ its compound cheJcJ01? “ie'S? C0™P°und b°dæs the combination must be ™ dlst;nguished from mechanical in which the miv hi‘I,are ,simply miXf‘d together; thus, carbon and oxyden tempera^re Vrik 7atly “ ? ’S Possible> bu‘ unless Ae comMne Tlw h« . they wil1 not ^emically omoine. Lhe heat at which bodies will so combine is called IbouVf« on^empTtUr?’ and this for c“rb°n and oxygen it about: 1 800 pso that if our mechanical mixture be subiected to this heat the two elements will unite if allowed free access to each other m the proportion of 1 of carbon to 2 of oxyden onemionCaif h’C aCid’ ,and giving Off intense heat thé ! purt of cJbon mnVer’ th®.air suPP>y is contracted, then the part ot carbon may combine with but 1 of oxvg-en and fonn ’ W'th th? bad reSult to be describfd later 0 *:he purposes of companson it is essential to have a of °f Umt^ and the Unit of heat is taken as the quantity Thus?f ! lbrfd raise the temperature of i-lb. of water i ° F. 1 J-k of water.ls of the temperature of 6o° F. and a source of heat is apphed to it until it reaches 610 F then one unit of heat has been absorbecl in it. The unit of work is the amount required to raise one Ib. one foot hi^h and is Si ed isllfted 0npfnCt S° that lf ? pieCe of iron of the weight of one Ib ifted one foot, one unit of work has been pertormed It bein^ it ^eon |aniCal faCt that heat and work are mutually convertible it is only necessary to have a rate of exchange; this is found to be 772 foot-pounds ofwork; so that if a weight of 772-lbs^