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4. Creosote oil is a mixture of bodies which have not yet been 
thoroughly investigated. It is at present used mainly for pickling 
timber ; but as its composition and properties are more fully in- 
vestigated, it is expected to increase in commercial importance. 
5. Anthracene (C,,H,,) was discovered by Dumas and Laurent 
in 1832. It was not, however, of much commercial value until 
1868, when Graebe and Liebermann found that it could be con- 
verted into alizarine (C,,H,O,), which is the colouring matter of 
the madder root. Alizarine was until very recently made from 
the root of the madder plant, of which the yearly crop was 
70,000 tons, at £45 per ton; representing an annual value of 
£3,150,000. Of this crop, the United Kingdom consumed 23,000 
tons, having a value of £1,000,000 sterling. Madder is now only 
grown in very small quantity indeed ; having been superseded by 
the more reliable and superior artificial substance, which in 1883 
was sold at about 2s. 6d. per pound. 
Having referred to two industries which have very largely 
developed, I will now mention two comparatively new ones. 
which are at present receiving great attention. The first is the 
recovery of the nitrogen remaining in bituminous shales, after 
the extraction of the oily matter; and also that from the coke 
produced in gas manufacture. It is now well known that only a 
small fraction of the nitrogen contained in these shales and coals 
used in destructive distillation is, under the ordinary conditions 
of working, obtained as ammonia. It has, therefore, been the 
object of several chemists to extract from the solid residues, as 
far as possible, the nitrogen in combination with hydrogen. 
Messrs. Young and Beilby have treated spent shale with highly 
superheated steam ; the result being that the yield of ammonia 
has increased 180 per cent. They find that with highly carbon- 
aceous spent shales or other bodies containing a large percentage 
of carbon, the process is accelerated by the admission of a small 
proportion of air. In this manner they propose to convert coke 
into heating gas and ammonia; the heating gas consisting of 
carbonic oxide and hydrogen, which are the active constituents, 
and diluted with the nitrogen of the air used in the process. 
For gas manufacture the present practice obtains about 15 per 
cent. of the total nitrogen of the coal as ammonia; while about 
50 per cent. remains in the coke, and the remaining 35 per cent. 
is probably liberated as free nitrogen in the gas. 
Secondly, there are the improved methods of making metal- 
lurgical coke. Among the many forms of coke-oven recently 
put forward, I may select the Jameson and Simon-Carvés as 
perhaps the best. In the former of these two, the principal 
novelty consists in the altered form of floor given to the ordinary 
beehive oven; Mr. Jameson inserting a floor which is perforated. 
The perforations lead into a flue laid from the centre of the floor 
