COAL-TAK 305 



interest would justify the Government fixing, by law, a reason- 

 able time-limit beyond which no beehive coke oven would be 

 allowed to remain in operation, except by express sanction of 

 the State, and then only on special circumstances being proved." 



In a work of this kind the subject cannot be pursued further, 

 but it must be obvious to the most superficial reader that reform 

 in the use of our national coal supplies is urgently necessary. 

 It must be remembered also that though industrial waste is 

 more readily open to supervision and control, the domestic 

 hearth is responsible for a large part of the useless consumption 

 which goes on. 



Now resuming the subject of this chapter, which is Coal-Tar, 

 we may notice in passing the estimate which was drawn up 

 in the year 1901 of the amount produced by all the countries 

 of the world. From the nature of things this can only be re- 

 garded as approximate, and from what has been said the total 

 amount is probably now much greater. 



Tons. 



United Kingdom . . . . . 908,000 



Germany 590,000 



United States (including water-gas tar) . 272,400 



France 190,680 



Belgium, Holland, Sweden, Norway and 



Denmark 272,400 



Austria, Kussia, Spain and other European 



countries 199,760 



All other countries 227,000 



Total . 2,660,240 



Coal-tar is distilled in large iron stills set in brickwork and 

 heated by a fire below. Each still is a sort of boiler which holds 

 from 20 to 30 tons. It has a slightly domed head with a wide 

 pipe by which the vapour is carried into a spiral continuation of 

 the same called a condenser and in which it is liquefied. The 

 condensed product runs into different receivers. First come 

 some ammoniacal liquor and the light oils which float on water. 

 These are followed, as the temperature rises, by heavy oils 

 which sink in water. The residue left in the still is pitch, which 

 while still hot is run out into large iron vessels where it cools 

 and gradually becomes solid. Ordinary gas works tar is an 



