Opinion,

The right of the borough of Saltsburg to use the gas free of charge for lighting its streets is admitted, but the extent of the right depends on the construction of the words “street lamps ” in the ordinance of March 12,1888. The word lamp, considered with reference to the general idea conveyed, is as definite as any word in the language, but with regard to the particular form, material, and method of operation of the instrument itself, and the substance used as a light producer, it is as vague as the name of any concrete article in daily use can well be. As to these matters, therefore, its meaning must depend largely on the context, and on the time, place, and habits of the people with reference to which it is used. Thus, in the early years of all the members of this court, a lamp would have been universally understood, not only in Pennsylvania but throughout the United States, as one which burned whale or lard oil; and a street lamp would have had the same meaning everywhere, except in a few cities where gas had rather recently supplanted oil, but where the old name still held its place. Probably at the present day a street lamp would be understood everywhere but in the smaller villages as a gas lamp, but in places within the natural-gas region the old meaning may have already become unsettled, or a new one established. This is what is claimed in the present case.

The answer of the borough sets up that “ in the popular understanding, and in the understanding of persons familiar with the manufacture and fitting up of appliances for lighting'streets with natural gas, the word lamp has the same meaning as the words burner, light or torch. In all the towns and cities where streets were thus lighted with natural gas, open lights were alone used for this purpose; a fact which must have been known to complainant, and it was in view of this condition of things the contract was made. ” The affidavits on behalf of the respondents amply sustain this averment of the answer, while, on the other hand, it is not opposed by the evi*259dence of complainant. The affidavits on behalf of the latter speak in general terms of the open lights as wasteful and extravagant, but not a single one of them denies that open lights were and are still commonly used in the natural-gas region of Pennsylvania, nor mentions any place in this state where enclosed lamps are successfully used at the present day. The only places specified in which enclosed lights are used are in Ohio and West Virginia. The clear preponderance of evidence is with the respondents, and settles the meaning of the word as used by the parties in 1888.

This result is not at all affected by the agreement of March 28, 1889, which is not a construction of the ordinance by the parties, but a compromise of conflicting views, for the sake of peace. It is expressly temporary in character, and, on its termination, each party was remitted to its claim under the ordinance.

We have thus expressed our views on the merits, on account of the public interests and convenience involved, but the case is clearly not one for equity at all. The basis of the complaint is that the borough is using more gas than it is entitled to, and complainants ask the court to assist them to remedy their alleged grievance by tearing up the streets and cutting off even the use of the gas to which the borough is admittedly entitled. The court did not go as far as it was asked to, but it went farther than the limits of equitable jurisdiction in this class of cases, as defined in Grubb’s App., 90 Pa. 228.

The common law is the living science of justice, and adapts the application of fixed principles to changes in the affairs of men. Natural gas is a newly discovered, and as yet unfamiliar product of nature, and the law will recognize a general progress in its economical, prudent, and profitable use. If, therefore, the plaintiffs can hereafter show that open lamps are extravagant, wasteful, and unnecessarily burdensome to the company, it may be that an action will lie for the value of the excess. But, as open lamps were the ones in contemplation at the date of the contract, the onus will be on the plaintiffs to show a progress in the art of illumination that has superseded the use of them, and made it unreasonable.

Injunction dissolved, and bill dismissed, with costs.