35 
to a large gas-main running alongside the battery of ovens. The 
gas produced is exhausted by machinery; and the tar and am- 
monia are abstracted in the same way as in gas-works. As in 
ordinary coke-ovens, so in this process—a small proportion of air 
is drawn into the oven; and thus a partial combustion takes 
place. The coke produced by this method is very hard and 
compact, but the tar is of inferior quality; consisting largely of 
parattins, with only a slight trace of toluene and xylene—no ben- 
zene, naphthalene, or anthracene. The yield of ammonia is 
comparatively small, being equal to about 9 lbs. of sulphate per 
ton of coal used. The Simon-Carvés process is a destructive 
distillation ; no air being admitted to the oven. In the early 
forms of this system the temperature was about 2200° Fahr. ; 
but in the more improved form, with recuperator, a temperature 
of about 3000° Fahr. Each oven is charged with about 43 tons 
of coal; forming a mass about 6 feet high by 18 inches thick. 
The oven is surrounded, sides and bottom, by flues, in which the 
gas produced by the process is burnt (after purification). By this 
arrangement the mass of coal is kept for 60 hours at such a 
temperature that it partially fuses—at any rate in its lower 
portion; and the weight of the column causes it to consolidate. 
The products being drawn off at the top, they have in great 
measure to pass through the incandescent mass, and thus become 
partly reduced to carbon. This helps to fill up the pores of the 
coke more than is the case in gas making. This coking process 
differs from gas manufacture mainly in the employment of a large 
compact mass. The working results of 25 ovens, used at Messrs. 
Pease’s works, Crook, near Darlington, are 6°12 gallons of tar, 
and 27-7 gallons of ammoniacal liquor (6° to 7° good Twaddel) 
per ton of coal. About 15 per cent. more coke is obtained by 
this method than by the ordinary beehive oven; and further, the 
tar produced is of good quality. Mr. Watson Smith, F.LC., 
F.C.S., states that its gravity is 1200; it is thus somewhat denser 
than ordinary gas tar. It is rich in anthracene and naphthalene ; 
but less rich in benzol and phenols. The adoption of these 
ovens is extending, and it is hoped they will continue to do so; 
because by their use the smoke and dirt (which are the usual 
accompaniments of coke-ovens) are utilized, instead of polluting 
the air and damaging vegetation. 
A consideration of these samples of industrial applications 
will enforce the importance of the three influences enunciated 
at the beginning of the paper, by showing the differences in the 
products of destructive distillation under various conditions. 
The subject of the paper was illustrated by specimen products 
of the manufactures referred to. For those relating to shale dis- 
tilling the lecturer was indebted to the kindness of Mr. J. Fyfe, 
of Young’s Paraffin Light Company; and for the use of those 
