40 



SCIENCE. 



[Vol. IX., No 306 



gheny Mountains, and extending a very short dis- 

 tance into Ohio, New York, and West Virginia, 

 and it is also stated to have been found in a very 

 limited extent in Illinois and Kansas. 



The most important economic locality is that in 

 the immediate vicinity of Pittsburg, vrhich sup- 

 plies that city with the fuel for the vast iron and 

 glass works and for numerous private dwellings. 

 There are 6 natural gas companies in that city, 

 managing 107 wells, and supplying the gas 

 through over 500 miles of pipe, of which 232 

 miles are situated in the city proper. The total 

 area of pipe leading into Pittsburg is given as 

 1,346,608 square inches, and the total capacity of 

 the lines is estimated at over 250,000,000 cubic 

 feet of gas per day. The largest company is the 

 Philadelphia natural gas company, which supplies 

 over 400 manufactories and over 7,000 dwellings 

 with the entire amount of fuel consumed. The 

 composition of natural gas varies greatly, both in 

 specimens from different wells and in those from 

 the same well at different times. In general 

 terms, it can be described as a mixture of hydro- 

 gen, nitrogen, and marsh-gas, with occasionally 

 higher carbon compounds. It burns with a nearly 

 colorless flame, and gives off no odor or delete- 

 rious matter. 



In speaking of the use of natural gas for do- 

 mestic purposes, Mr. Ashburner pointed out the 

 great advantages which a gaseous fuel has over a 

 solid one like coal, and stated his belief that the 

 greatest of the advantages of the discovery of 

 natural gas was that it had proven the great 

 economy and practical utility of such fuel. A 

 thousand cubic feet of gas was calculated to equal 

 in heating capacity 55 pounds of coal. He stated 

 that the use of natural gas for domestic purposes 

 would not have been possible without the inven- 

 tions of Mr. Westinghouse of Pittsburg, two of 

 whose inventions the lecturer illustrated. One of 

 these inventions was intended to prevent leakage 

 from gas-pipes, and to locate leaks accurately 

 when they occurred. The leaking gas is conveyed 

 to the nearest lamp-post and there consumed. 

 Another invention was a most ingenious pressure 

 regulator, which not only regulates the pressure 

 at which the gas is supplied to the burners, re- 

 gardless of the pressure in the mains, but, in the 

 event of the pressure in the mains dropping to 

 zero, automatically shuts off all gas from the 

 house ; nor is it possible to turn the gas on again, 

 without violence to the regulator, until every 

 source of escape of gas larger than a pin-hole leak 

 has first been corrected. A model of the regula- 

 tor was exhibited. The lecture was illustrated by 

 drawings and maps and by a small working model 

 of a well-boring apparatus. 



In answer to inquiries, the lecturer stated that 

 the source of natural gas was certainly capable of 

 exhaustion, but that he did not think there was 

 any imminent danger of such a calamity. The 

 sources of supply would certainly last many 

 years; and he believed, that, before they would 

 give out, a method of producing an artificial gas 

 would be invented which would perfectly sup- 

 plant the present natural gas. The cost of natural 

 gas could not be compared with our coal-gas, for 

 the reason that the natural gas was not sold by 

 meter. The consumer makes a yearly contract 

 with the company to supply him with light or 

 fuel, or both, at certain rates. A house contain- 

 ing twelve rooms costs, to heat and light, from 

 $70 to $90 a year. The use of the gas is most 

 satisfactory ; for, by means of an automatic regu- 

 lator, every room of a house may be kept at a 

 temperature not varying two degrees, regardless 

 of the condition of the outside temperature or the 

 pressure on the mains. Defects and troubles were 

 met with from lack of understanding how to 

 properly regulate the supply or the combustion. 



In reply to the question as to whether he 

 thought it wise for the city of Philadelphia to 

 lease the gas-works for a term of years, Mr. Ash- 

 burner replied, that, as a business-man, he would 

 say that any scheme for supplying the ordinary 

 form of coal-gas was, at the present time, ex- 

 tremely uncertain as a business venture. He 

 believed that a very short time would demon- 

 strate that there was a method of generating a 

 fuel gas which would totally supplant all present 

 modes of heating, and that electricity had already 

 solved the problem of illumination. We were in 

 a transition stage with regard to both heating and 

 light, and for these reasons, and from this stand- 

 point, he would regard any movement as un- 

 desirable at this time. 



PURITY OF ICE. 



The state board of health of New York has 

 recently published a report on the purity of ice 

 from Onondaga Lake, the Erie canal at Syracuse, 

 and Cazenovia Lake, being the ice-supply of Syra- 

 cuse, The local board of health regarded that cut 

 from Onondaga Lake as being detrimental to 

 health. Into this lake discharges the creek of the 

 same name ; and into the creek is discharged the 

 sewage of the city of Syracuse, which amounts 

 to five millions of gallons daily. At the time the 

 inspection of this lake was made, there was a 

 margin of from one to four feet wide of black, 

 putrefying organic matter along the shores. The 

 analyses of the ice from this lake showed that it 

 contained probably from ten to twelve per cent 



