SCIENCE AND INDUSTRY. 
Powdered Coal as a Fuel, by C. F. Herington. New York. D. Van Nostrand Co., 
1918.—This informative book, which deals comprehensively with a subject attract- 
ing an increasing amount of attention, describes the various patents, designs, and - 
systems now in use in the United States. The main chapters of the book are 
devoted respectively to the preparation, feeding, and burning of powdered coal, 
and to its use in the cement industry, in reverheratory furnaces, in metallurgical 
furnaces, under boilers, and for locomotives. Powdered coal was first used on 
an industrial scale 44 years ago in the United States in cement furnaces, and at 
the present time fully 90 per cent. of the Portland cement made in that country 
is burned in kilns using powdered coal. In former years, oil fuel was used in 
the cement industry, but the increase in price of oil after 1895 made the use of 
that fuel almost impracticable commercially. This was the principle incentive 
for developing the use of powdered coal, which is specially suitable for the high 
temperatures required for the chemical combinations in the manufacture of 
cement. : 
By ordinary manipulation in the use of powdered coal, the temperature and 
quantity of fire can be changed as easily as a gas jet can be turned on or off. The 
response is instantaneous, and it is this particular feature which renders the use 
of pulverized fuel particularly suitable for metallurgical furnaces. Powdered coal 
is used in all kinds of steel and iron working, including ore-roasting, and in open- 
hearth furnaces, puddling furnaces, and pig furnaces. The present consumption of 
powdered coal in the United States is over 8,000,000 tons annually. 
The author states that the necessity for insuring supplies of oil fuel will soon 
eliminate it from railway motive power use. Though but little actual operating 
data are available, it appears that powdered fuel has special advantages for loco- 
motives by reason of its dependability, flexibility, effectiveness, and economy, and 
its ability to meet public demands for the reduction of smoke, soot, cinders, and 
work. The book is well indexed. It contains a valuable bibliography, and is 
admirably illustrated. » - 
The Prickly Pear in Australia, by W. B. Alexander, M.A. This is 
a bulletin (No. 12) just issued by the Institute of Science and Industry. 
It deals with one of the greatest obstacles which impedes pastoral and 
agricultural progress over a large portion of the Commonwealth. The 
magnitude of the problems connected with the eradication of the prickly pear 
is disclosed by the fact that an area of over 20,000,000 acres is infested in 
Queensland, and an area of over 2,200,000 acres in New South Wales. ‘The rate 
of increase of the pest is estimated at 1,000,000 acres per annum. No diserimi- 
nation is shown in the land that is attacked. Rich country is as quickly 
overcome as poor country, and in a short time is rendered unproductive and 
valueless. 
Owing to its tenacity of life, its armature of prickles and spines, and its 
succulent nature, the prickly pear plant is extremely difficult to eradicate. 
The cost of eradicating pear by manual labour from land thickly infested is 
prohibitive, except where the land is exceptionally valuable, and in consequence 
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