$36 
NATURE 
[JUNE 23, 1923 

present to his notice much more fully the contributions 
to the science and practice of fuel technology which 
have been made by America than would have been 
possible in anything like the same compass if 
corresponding notice had been taken of contributions 
to the subject from other than American sources. 
Partly perhaps on this account, the scientific treatment 
of fundamentals is somewhat sketchy and inadequate. 
Here, again, if the book is approached with the full 
knowledge that it is primarily concerned with the 
setting out of American contributions to fuel tech- 
nology and the treatment of American fuels (the latter 
according to title), little harm is done, and the many 
excellences of the book can be utilised to the full. 
Reviewing the work more systematically, after a 
first chapter on “The Coals of the United States’ 
(which includes a six-page table of analyses of repre- 
sentative coals), and a second on “ The Principles of | 
Combustion,” we find a full and informing chapter 
on “The Technology of Coke,” by F. W. Sperr, the 
chief chemist of the Koppers Company, Pittsburgh. 
This occupies 160 pages, and is well done, although it 
is charitable to suppose that the work of Sir George 
Beilby and others on the structure of coke during the 
last two years must have been published a little too late 
to allow of its consideration. A useful inclusion here 
Briquetted or compressed fuels are treated next, and 
various processes are described, but when the author 
says that “ there are no unsolved fundamental problems 
in briquetting practically any kind of material, especi- 
ally in the field of fuel,” and that “there is nothing 
that stands in the way of the design and construction of 
a briquetting plant to briquet any kind of coal,” he will | 
find many to question his judgment. 
An excellent economic review of coal preparation 
raises a number of interesting questions, and in dis- 
cussing power-generation and the possibilities of the 
turbine we are told that “higher efficiencies may be 
more readily obtained by using two vapors in series, 
such as mercury and steam. Mercury vapor has a 
much greater density than steam and a lower heat of 
vaporisation ; hence the spouting velocity is low and 
it may be used in a high-temperature turbine of very 
simple design. A mercury turbine and boiler are being 
developed by the General Electric Co.” 
“The Gasification of Fuels,” including that of low- 
grade fuels, is broadly treated by Mr. Coffin of the 
General Electric Co., and conveys a detailed descrip- 
tion of a horizontal rotary gas producer made by the 
General Reduction Gas and By-Products Co., for 
which quite high thermal efficiencies are claimed, and 
the capacity to deal with most unpromising materials, 
such as anthracite slush containing 20 per cent. moisture 
NO. 2799, VOL. 111] 
| Most producer projects look good on paper.” 
is a summary on methods of sampling and testing. | 

and 25 per cent. ash, a mixture of coke breeze and slush 
containing 45 per cent. of ash, and sawdust. The 
statement is made that it has been found possible to 
make methane from blue gas synthetically in the 
presence of a nickel catalyser, but an expansion of 
the term “ possible” would have been useful in this 
connexion, 
In the chapter on the “ Distillation of Coal at Low 
Temperatures” the excellent and comprehensive 
review of the history, theory, and practice of the low- 
temperature carbonisation of coal, which was sub-— 
mitted to the Society of Chemical Industry by Mr. Edgar 
C, Evans, has been printed in condensed form, and a 
number of processes are described in some detail. One 
of the most interesting chapters is on the use of finely 
divided fuel, the technique of this subject having been 
much more highly developed in America than in Great 
Britain. A chapter on “ Fuel Oil and its Utilisation ” 
is followed by one on “ Colloidal Fuel,” for which that 
well-known authority on the subject—Mr. Lindon W. 
Bates—has made himself responsible. Natural gas 
and producer gas technology are treated in turn, and we 
‘are informed that “lack of proper operating organisa- 
tion has been the cause of many failures,’ and that 
“another cause is the over-enthusiastic salesman. 
There 
is a section on freak producers, and a summary which 
includes such prohibitions as “Do not employ an 
engineer who has never made a mistake on producer 
gas work,” and “ Do not lose your nerve after the first 
six months of operation.” 
Water-gas does not receive anything like so much 
attention as might have been expected in an American 
work of to-day, and although some costs are given 
there is no satisfactory thermal or chemical analysis of 
the process. 
The chapter on “‘ Blast Furnace Gas ” is short, but use- 
ful. It is followed by one on the Dayton process, little 
known in Great Britain, which is essentially an air-oil-gas 
process in which partial combustion of the oil with air 
takes place within the retort, thus supplying internally 
the heat necessary for the thermal decomposition of the 
hydrocarbons. Theneed for external heating is thereby 
minimised. The nitrogen of the air used is, of course, 
present in the gas made, which may be of various 
grades. It is stated that approximately 4 gallons of 
fuel or gas oil is required for the production of 1000 
cu. ft. of 450 B.Th.U. gas. A statement which would 
require very serious examination before acceptance is 
that ‘theoretically it has been found, and under 
practical conditions of industrial operation it has been 
proved, that Dayton gas of 450 B.Th.U. per cu. ft. is 
required in no greater volume than illuminating gas 
of 630 B.Th.U. per cu. ft. for the same work.” The 
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