ON FLUCTUATIONS IN THE COMPOSITION OF 

 NATURAL GAS* 



By Francis C. Phillips. 



Presented by the C. M. Warren Committee, October 12, 18S8. 

 Received October 12, 1898. 



At the mills and factories of the Pittsburgh region the opinion is 

 often expressed by men in charge of steam boilers where natural gas 

 is the fuel used, that the gas fluctuates in its heating power, and that at 

 certain times more gas must be used than at others to accomplish the 

 same work. Changes of pressure in the mains, owing to varying 

 demands upon the supply, requiring that the valve controlling the 

 admission of gas to a boiler fire should occasionally be opened more 

 widely, might readily lead to the supposition that the gas at sucli times 

 possesses less heating power and consequently a different composition. 



No data as regards results in practice have been obtainable, but in 

 analyses of gas from various wells in the Pittsburgh region reasons have 

 been found for supposing that slight fluctuations actually occur in its 

 composition. With a view to a more complete study of the question, the 

 experiments described in this paper were carried out. 



As regards the character and number of its chief constituents natural 

 gas differs widely from coal gas, and from gas manufactured at high 

 temperatures in the various forms of producers. While in artificial gas 

 unsaturated compounds are present in great variety, natural gas is com- 

 posed mainly of hydrocarbons of the paraflin series, associated with very 

 small quantities of nitrogen, carbon dioxide, and water vapor. The 

 defines, represented mainly by ethylene, are found sometimes in extremely 

 minute proportion, so minute in fact that quantitative determinations are 

 a matter of difficulty, although they are qualitatively recognizable when 

 large volumes of gas are employed. Traces of organic sulphur com- 



* Acknowledgment is liere made of aid received from the C. M. Warren Fund 

 of the American Academy of Arts and Sciences, in conducting the experiments 

 described in this paper. 



