Apri 5, 1912] 
nite and peat, 60 per cent; or roughly, total in- 
crease of 150 per cent. over our present supply 
of marketable grades of fuel. The logical con- 
clusion from a careful study of the producer gas 
power situation is that the time is not distant 
when financial interests in power production will 
be directed toward the centralization of the pro- 
ducer-gas power plant at the mines and the dis- 
tribution of the energy developed either by high- 
voltage long-distance electrical transmission or by 
pipe systems for conveying the gas. 
Investigations in Relation to Fuels and Fuel Effi- 
ciencies: O. P. Hoop and 8S. B. Fuace, Bureau 
of Mines. 
The Bureau of Mines is engaged in investigating 
the general problem of the conservation of our 
mineral fuels by careful study of the problems of 
preventing waste in mining transportation and 
storage and of increasing the efficiency with which 
the fuel is finally used for heat, power, ete., and 
also the problem of utilization of inferior fuels 
not now generally used, owing to ignorance as to 
their value and the means of making that value 
available. The study of the problem of combus- 
tion for steam and for gas engines was inaugu- 
rated on a large scale in 1904, and is still in 
progress. At present the combustion of fuel for 
steam purposes is being examined in a specially 
constructed furnace permitting of the determina- 
tion of temperatures and chemical composition at 
short intervals between the fire and the stack, and 
the values of refuse collecting at mines and in 
yards, and of lignite, peat and miscellaneous 
wastes from various industries, as fuels for the 
producer gas engine are being carefully investi- 
gated. Also the advantages of briquetting for 
rapidly deteriorating fuels, the best methods of 
transportation and storage, the prevention of mine 
explosions, spontaneous combustion and smoke are 
receiving careful attention. The purchase of fuel 
on the basis of specifications covering heat value 
and composition with penalty and premium pro- 
visions has been materially advanced by the bureau. 
The investigations of the bureau have been favor- 
ably received and the results in application by 
fuel producers and users have been gratifying and 
encouraging to further work. 
With Special Relation to Safety in Mining, 
Quarrying and Metallurgical Operations: J. A. 
Houtmgs, Director, Bureau of Mines. 
The main purpose of the bureau is to increase 
health and safety in the mineral industries. It is 
endeavoring to collect statistics relating to acci- 
SCIENCE 
549 
dents and health conditions in and about mines, 
quarries and metallurgical plants, and is investi- 
gating the causes of accidents and the conditions 
inimical to health and safety. One of the most 
important investigations is that of the cause of 
mine explosions, which involves a study of mine 
gases and coal dust and the conditions under which 
inflammable gases and dusts may be ignited. A 
related investigation, that of explosives used in 
coal mining, was undertaken to determine what 
explosives are least likely to ignite gases or coal 
dust. Another investigation deals with the pre- 
vention of accidents from electrical equipment in 
mines. The miscellaneous accidents in mines, in- 
cluding falls of roof, are also being investigated. 
These miscellaneous accidents, though individually 
small, each year kill more miners than the great 
explosions. The mine-rescue and first-aid work of 
the bureau has attracted more attention than its 
investigations. The bureau now has six mine- 
rescue stations and seven mine-rescue or mine- 
safety cars in the more important coal fields of 
the country. The work of these stations and cars 
is largely educational, training miners in mine- 
_rescue and first-aid methods and demonstrating 
equipment and appliances. More cars and more 
equipment are needed. It is expected that within 
a few years the bureau will have trained 20,000 
miners, who will be organized into local mine- 
rescue and first-aid corps, to be supported without 
aid from the federal government. The success of 
the bureau’s work in behalf of safety will depend 
on how far this work receives the cooperation of 
mine owners and miners. The federal government 
can conduct investigations, the states can embody 
the results of these investigations in laws, but the 
cooperation of mine owner and miner are essential 
to suecess. The progress in lessening accidents is 
slow and there is serious need for extending the 
work of the bureau. Its investigations hitherto 
largely confined to the health and safety problems 
about coal mines, should cover similar problems 
at metal mines, quarries and metallurgical plants. 
PAPERS ON AERONAUTICS AND AERIAL ENGINEERING 
Holes in the Air: W. J. Humpureys, U. S8. 
Weather Bureau. 
Aeronauts have adopted the picturesque phrase, 
‘‘holes in the air,’’ to describe that condition of 
the atmosphere that makes uniform horizontal 
flight impossible, and causes great danger to the 
aviator. Among the atmospheric conditions that 
may cause a greater or less drop of the aeroplane 
