CLAY WORKING INDUSTRIES. IS) 



variations would- be' id the state' of the atmosphere and the closeness of 

 the setting of the ware in the kiln'. In a compound stack, the draft 

 varies 'greatly according to the number of kilns' on full fire at once, and 

 the burner, unless he is a man of intelligfenceandgood judgment, is likely 

 to have constant trouble from this caused and' no matter "ho# good judg- 

 ment he may possess, the more judgment' requiredj the more frequent 

 will the failures be. '-'' ' ■:■■.,. ■>..-, ;, . , • 



2d. One stack permits of more easy regulation that ttoo or more. 

 One dataper affects all parts alike, 'while in niultiple' stacks the number 

 of 'conflicting currents prevents'the burners from securing very accurate 

 regulation. ' ' " ■ • ' : ; ■ ' •< ' ■ . i. 



On the other hand, it may be urged in favor of the, compound stack, 

 that the heat of one kiln; just- finishing "or ■ cooling off, gives powerful 

 assistance to the draft of another which is just starting' and whose draft 

 is therefore in the weakest condition. This assistance is of great benefit 

 in getting through the drying out and heating up stages of the burn; but 

 as previously'shown.'it'becdniesa 1 source of danger when the vitrifying 

 stage is attained. 'Also in favor of multiple stacks it iriay be Urged that 

 they are cheaper to construct than one stack of 'any pretensions, and also 

 they have 'the great advantage of using no yard robin, being built in the 

 circumference of the' kiln walls, 1 and thus affording greater economy of 

 space and convenience of arrangement than can be attained with either 

 single or compound stacks. '•■■■'>■■ <-■■■■ ->'' 



In producing the draft of square kilns, the conditions vary somewhat 

 from those of round kilns. By a square kiln is meant a rectangular one; 

 not one of equal length and breadth. In fact the' square kilns in use, are 

 .usually eighteen feet wide, by seventy or 'eighty feet long. In kilns of 

 this size, it is impossible to devise any plan which shall enable 'one stack 

 to reach the various parts 'of the kiln 'with equal ■ efficiency. ; Therefore, 

 a ''multiplicity 'of 'stacks' is a necessity" in- this' type of kiln. 'But they may 

 still be' arranged so as to-be under as much controlas'the single stack on 

 the round kilnor they-may be arranged- at such 'frequent'" intervals along 

 .the -sides as to produce entirely different effects; ' • ■ - <■ " : ■ : ; ' ' - 

 • • - -The most' excellent burning that wais seen in the state-ina' rectangu- 

 lar kil'n was accomplished 1 iU one which was abdut thirteen ' feet wide- by 

 thirty' feet long. 'The "stacks- were arranged at both ends of the' kiln- and 

 the main"' central flue 'connected each stack.- 'This' flue wais'divided by- 'a 

 horizontal partition into a top and 'bottom' compartment.'' The bottoni 

 Compartment/ opened only mtothe Central third of the kiln's length,. :the 

 top parts drained the two end thirds of the kiln-- 'each to 'its -own stack; 

 by- damper* the whoie>draft or any part of itcottld be 1 ''directed to either 

 end' or 4ihe center: ' By-sUch-an' arrangement,' where' control is possible, 

 twb or more stacks* are an advantage-; in fact; iiilong kilns they are almost 

 a necessity to secure) anything like the : be'st work; ' By the Use' of alafge 

 nuniber : of small stacks built in the' kiln Walls-the probleni ' is 1 sdmewhat 



