542 



SCIENCE 



[N. S. Vol. XXVIIl. No. 721 



cement manufactured and used in the 

 United States has increased each year until 

 now it has reached vast proportions. Its 

 use will be greatly increased in the future, 

 especially in structural work, as we learn 

 more and more about the strength of con- 

 crete reinforced with steel. The United 

 States gOYernment, engineering concerns 

 and technical colleges are making an ex- 

 tensive study of this great engineering 

 question and the results of their researches 

 are put into practise as soon as they are 

 published. Every engineer believes that 

 the opportimity for this kind of investiga- 

 tion is very great and that it should be 

 encouraged by both national and state gov- 

 ernments. 



FUEL 



Manufacturing industries depend upon 

 fuel, and cheap fuel is a vital element of 

 our supremacy in the world's markets. 

 The amount used at the present time in 

 the United States is very large. In 1906 

 the coal mined amounted to four hundred 

 million tons of a value of five hundred 

 and ten million dollars. The petroleum 

 was valued at ninety million dollars; nat- 

 ural gas at fifty million dollars; coke at 

 one hundred and ten million doUars and 

 artificial gas at thirty million dollars. 

 The total value of all fuels, including by- 

 products, was almost one billion dollars. 



Coal is found in abnost every section of 

 the United States, twenty-nine out of forty- 

 six states having coal beds. Natural gas 

 and petroleum are also found in many of 

 the states. No matter how large the supply 

 of these fuels may originally have been, a 

 yearly drain, such as just mentioned, will 

 inevitably in a few years sadly deplete it, 

 and the amount used is increasing every 

 year and at a very rapid rate. But this is 

 not aU ; the figiires just given are those for 

 the fuel taken from the ground and used, 

 but the amount wasted doubles or trebles 

 this total. Although this latter has not 



been put to any use, it has been destroyed 

 so far as its future usefulness is concerned. 



Natural gas is one of the most perfect 

 fuels in existence. It is found under such 

 pressure that it can be carried long dis- 

 tances and delivered in the factory ready 

 for use. The turning of a cock regulates 

 the supply and there is no dirt or loss. 

 Many wells which yield small amounts are 

 allowed to waste their supply in the air 

 and it has frequently happened that the 

 product of large weUs is more or less 

 wasted because proper piping is not at 

 hand or proper precautions have not been 

 taken. In many oil wells there is more 

 or less gas and little if any effort is made 

 to secure this supply. One geologist esti- 

 mates that at least a billion cubic feet of 

 gas per day are allowed to go to waste in 

 the United States. Only one state, Indi- 

 ana, has passed stringent laws against this 

 waste. This state found that her supply 

 of natural gas was rapidly being exhausted 

 and that factories formerly dependent upon 

 it were obliged to change to some other 

 form of fuel. After a large part of the 

 supply had been exhausted, laws were 

 passed forbidding operators to open gas or 

 oil wells until precautions had been taken 

 to save all the gas. 



The waste in coal mines is very great. 

 Nearly every coal vein has streaks of sul- 

 phurous or bony coal mixed with the first- 

 class material. This contains a large 

 amount of carbon, but is not as valuable as 

 some parts of the seam ; it is, therefore, left 

 in piles inside the mine or dumped upon 

 the cubn bank on the outside. The amount 

 of this low-grade coal varies from ten to 

 fifty per cent, in every mine, and under the 

 present system of mining and of coal using 

 this is an absolute loss. As the roofe of 

 coal mines will not support themselves and 

 as timber is expensive it is the custom to 

 leave great piUars of coal in the mine as 

 supports. As a rule, these pillars are not 



