eral with peculiar attributes which require the application of precedents arising out of ordinary mineral rights, with more careful consideration of the principles involved than of the mere decisions. Water and oil, and still more strongly, gas, may be classed by themselves, if the analogy be not too fanciful, as minerals feræ naturæ. In common with animals, and unlike other minerals, they have the power and the tendency to escape without the volition of the owner. Their fugitive and wander- ing existence within the limits of a particu- lar tract is uncertain;' (per Agnew, C. J. in 80 Pa. 147). They belong to the owner of the land, and are part of it, so long as they are on or in it, and are subject to his control; but when they escape, and go into other land, or come under another's control, the title of the former owner is gone. Possession of the land, therefore, is not necessarily possession of the gas. If an adjoining, or even a distant, owner, drills his own land, and taps your gas, so that it comes into his well and under his control, it is no longer yours, but his." Per Mitchell, J., in 130 Pa. 235. Under a lease of land for the sole purpose of drilling and operating for oil and gas, the lessee's right in the surface of the land is in the nature of an easement of entry and ex- amination, with a right of possession where the particular place of operation is selected, and the easement of ingress and egress, transportation and storage; id. Whether the words "other valuable volatile substance" in a lease when they were used with petroleum, rock, or carbon oil, will include gas is a question for a jury, as the words have no settled meaning; 11 Pa. 31. The words oil and gas in a lease have been held not synonymous; 6 Atl. Rep. (Pa.) 74; it is a fuel; 114 Ind. 338; but it has been held that a company incor- porated for supplying heat cannot also fur- nish natural gas; 108 Pa. 126. Natural gas is as much an article of com- merce as any other product of the earth; 120 Ind. 575; and a state statute making it unlawful for any person to conduct nat- ural gas out of the state violates the pro- visions of the federal constitution vesting in congress the regulation of interstate com- merce; id.; 118 Pa. 468. The business of transporting and fur- nishing natural gas is a public use, and the right of eminent domain may be constitu- tionally granted to companies engaged in it; 5 Cent. Rep. (Pa.) 564; the business is transportation of freight; 118 Pa. 408. Because of the public nature of the busi- ness taxation may be authorized for sup- plying it to municipal corporations; 39 Fed. Rep. 51; and any unreasonable restraint upor the business is against public policy; 130 111. 268. It was held that under the Pennsylvania general incorporation act of 1874, under which companies for the manu- facture and supply of gas were formed, natural gas companies could not be incor- porated; 108 Pa. 111; 111 id. 35. Conse- quently a general law was passed providing for such companies under which, when lawfully incorporated, may they exercise the right of eminent domain and the grant of the power is constitutional: 120 Ind. 581; 63 Barb. 437; 115 Pa. 4; 160 id. 367; and the use of city streets for that purpose imposes no additional servitude; id. In Pennsylvania, the courts of common pleas may hear and determine controversies be- tween natural gas companies and munici- palities as to the manner of laying their pipes; 115 Pa. 4. A right to take natural gas from land under the Pennsylvania act of Apr. 7, 1870, P. L. 58, is not land held in fee, subject to be sold under a special fi. fa, against an in- solvent corporation; 162 Pa. 78. The lessee for oil and gas, having drilled a well and tapped the gas-bearing strata (the only one in the land), has both the possession of the gas and the right to it, and the owner will be enjoined from drilling; 130 Pa. 235. A lessee for oil only who took from the well both oil and gas was held not accountable to the lessee for the gas, which is, like air and water, the subject only of qualified property by occupancy; 28 W. Va. 210. From the nature of the gas, a lease of well- rights is necessarily exclusive so far as con- cerns the leased premises themselves; id.; 130 Pa. 235. A person who has a natural gas well on his premises has the right to explode nitro-glycerine therein for the purpose of increasing the flow, although such explo- sion may have the effect to draw gas from the land of another; '181 Ind. 599. See also as to natural gas, 30 Cent. L. J. 497; 29 Am. L. Reg. 93, 102; 34 Am. & Eng. Corp. Cas. 46-8. The rights and liabilities of gas com- panies are, in the main, the same, whether they are engaged in the business of supply- ing artificial or natural gas. Municipal lighting. The business is usually carried on by companies acting either under a legislative or municipal fran- chise or contract, or directly by the munic- ipality under express legislative authority or implied power. As to the impli