12 BULLETIN 102, PART 1, UNITED STATES NATIONAL MUSEUM. 
are long narrow rectangular gas heated inclosures, ranged side by 
side in batteries, to allow for mechanical charging and discharging 
and similarly the treatment accorded the various by-product recov- 
ering steps is marked by a maximum of saving elaboration. The 
general nature of the procedure will be found illustrated and 
explained on plate 9. 
Tracing the course of the operations as depicted it will be ob- 
served that in addition to coke as the major product, the output 
includes gas, tar, and ammonia, the latter either as such or in the 
form of the sulphate. By the introduction of additional installa- 
tions, omitted in the interests of simplicity, the segregated recoveries 
may and commonly are extended to include benzol and perhaps one 
or two other derivatives of lesser import. These, together with a 
12 to 15 per cent increase in the coke recovery, constitute the direct 
results accruing from the modern type of operations as contrasted 
with the crude procedure represented in the beehive oven. More 
definitely expressed, the contrast means a saving of around 200 
pounds of coke, about 5,000 cubic feet of gas, some 15 gallons of tar, 
and the ammonia in 20 pounds of ammonium sulphate along with 2 
gallons of benzol for every ton of coal coked. 
The operations represented in the illustration with the products 
given comprise the immediate field of by-product carbonization as 
employed in direct opposition to the beehive type of procedure and 
to the operations growing out of the gas retort bench. The develop- 
ment of the principle has not stopped here, however, but has been 
extended to fulfill a far greater, more comprehensive function with 
reference to human welfare through what is termed the coal-product 
industry and its consequent coal products or coal-tar derivatives. 
The diagram prepared by the United States National Museum’s 
valued contributor, Mr. C. G. Atwater, and reproduced herewith 
through the courtesy of the Barrett Co., of New York, outlines 
better than words the whole potential significance involved. 
The diagram is suggestive in three directions of importance in the 
present connection. First of all it brings out the relationship of by- 
product coking to the coal-product industry as a whole; namely, 
that of being only a preliminary though an indispensable prelimi- 
nary to the whole. Next it provides a definite basis for a compre- 
hensive imaginative grasp of what the industry in its fullness of 
development has been made to contribute toward furthering the ends 
of progress. Finally, it leads to the all-important conception of a 
single great intricate evolutionary creation, the various specific in- 
dustrial members of which can function only as they operate in 
coordination with the rest. These three are the essentials funda- 
mental to an understanding of the coal-product situation as it has 
come to exist in the United States to-day. 
