Opinion by

Under the construction of the ordinance of May 22, 1895, which the counsel for the appellant ask us to adopt, their statement of the question for decision would be correct. It is as follows : “ Is an ordinance of the city of Pittsburg, enacted in 1895, which authorizes the imposition of a penalty of not less than $10.00 or more than $50.00, for the emission for over three minutes’ duration at any one time, of smoke which is more than *553twenty per cent black from any chimney or smokestack within the city limits, where bituminous coal is used as fuel, in connection with boilers for heating and power purposes, invalid on the ground that it is unreasonable or unconstitutional?” We are not prepared to commit ourselves to the proposition that such an ordinance would be invalid on either of the grounds above suggested, or upon the ground that it would transcend the powers possessed by the city. But before discussing or expressing a more decided opinion upon that question we deem it advisable to determine whether the ordinance of May 22, 1895, will bear the interpretation contended for by the appellant’s counsel.

The 1st section declares “ the emission of more than twenty per cent of black or dark gray smoke from any chimney or smokestack where bituminous coal is used in connection with boilers for heating or power purposes,” to be a “ public nuisance.” No penalty is annexed. “ It is settled that, within constitutional limits not exactly determined, the legislature may change the common law as to nuisances, and may move the line either way, so as to make things nuisances which were not so, or to make things lawful which were nuisances, although by so doing it affects the value or use of property: ” Per Holmes, J., in Commonwealth v. Parks, 155 Mass. 531; 30 N. E. Repr. 174. So also the corporate officers of a city, having power “ to provide for the safety, preserve the health, promote the prosperity and improve the morals, order, comfort and convenience of the corporation and the inhabitants thereof,” may by ordinance duly enacted not manifestly unreasonable or oppressive, nor unwarrantably discriminatory prohibit things which were not public nuisances at common law, and the fact that it declares the thing prohibited a public nuisance would be no ground for denying validity to the penal provision of the ordinance. In an action or proceeding to enforce the penalty annexed to the violation of such an ordinance, the only question would be whether the alleged offender had done the prohibited act. He could not defend upon the ground that it was not a nuisance in fact, nor upon the ground that the enactment of the ordinance was unwise, inexpedient or unnecessary. “ Much must necessarily be left to the discretion of the municipal authorities and their acts will not be judicially interfered with unless they are manifestly un*554reasonable and oppressive, or unwarrantably invade private rights, or clearly transcended the powers granted to them: ” 1 Dillon on Municipal Corp. sec. 379; O’Maley v. Freeport Boro., 96 Pa. 24; Fisher v. Harrisburg, 2 Grant, 291; Livingston v. Wolfe, 136 Pa. 519; Wilkes-Barre v. Garabed, 11 Pa. Superior Ct. 355; Philadelphia v. Brabender, 17 Pa. Superior Ct. 331; 201 Pa. 574. But while the inclusion in such an ordinance of a declaration that the thing prohibited is a public nuisance would not invalidate the ordinance as a whole, it is equally clear that it would not make it a nuisance if it was not so in fact. M uch clearer is it that a mere declaration in án ordinance with no penalty annexed, that a certain act or thing shall be deemed a public or common nuisance, would not have that effect and thereby subject the offender to indictment under the general statute law punishing that offense. So far as we can see the 1st section of this ordinance amounts to no more than a mere declaration of the opinion of the municipal authorities, which binds no one. That which Blackstone declares is the most effectual part of a law is lacking. “ For,” as he says, “it is but lost labor to say, ‘do this or avoid that’ unless we also declare, this shall be the consequence of your noncompli-» anee: ” 1 Blackstone’s Commentaries, 57. The same objection applies with equal force to the 2d section of the ordinance.

The 3d section of the ordinance reads as follows :

“ Section 3. Any corporation, copartnership or individual who shall or may allow, suffer or permit smoke from bituminous coal to be emitted or to escape from any chimney or smokestack used in connection with boilers for over three minutes’ duration at any one time, shall in addition to any and all law requiring the abatement of nuisances, forfeit and pay to the city of Pitts-burg for every such offense, a sum not less than ten dollars ($10) or mo're than fifty dollars ($50) to be recovered before any al'derman of the county of Allegheny or any police magistrate of the city of Pittsburg as debts of like amounts are now recoverable.”

It is unnecessary to take up time and space in the discussion of the question whether the courts have power to declare an ordinance void for unreasonableness. Nor is it necessary •for us to discuss the unreasonableness of an ordinance that prohibits the emission of any smoke whatever from bituminous *555coal for a longer period than three minutes. That the court has such power and that the enforcement of such ordinance would be impracticable, not to say impossible in present conditions are propositions not seriously controverted by the appellant’s counsel. But it is argued that it would not be so if the words “ more than twenty per cent black or dark gray ” were inserted immediately before or immediately after the word “ smoke,” that in construing the section we are warranted in assuming that it was only that kind of smoke which the municipal authorities had in view, and that, therefore, we would be warranted in reading those words into this section. The obvious answer to this suggestion is, that the section is complete in itself; it is the only section that has a penalty annexed; it makes no reference whatever to the first two sections, and it is plain and unambiguous in terms. Standing by itself it needs no construction. In an action for the recovery of the penalty nothing more need be proved than is there required. It is only by combining the 1st section, which as we have seen is nugatory as well as unreasonable with the 3d section, which is manifestly unreasonable, that an ordinance can be evolved which even the appellant’s counsel find themselves willing to defend. This might be permissible if there were anything in the ordinance itself to show that the qualification as to time limit was intended to apply to the offense defined in the 1st section or that the qualification as to blackness was intended to apply to the offense defined in the 3d section. While the 1st section is connected with the 2d by reference no such connection exists between the 1st and the 3d. The latter stands by itself and was evidently intended to express the entire thought of the legislative body as to the offense to which a penalty was annexed. It is no more permissible to read the qualification as to blackness into the 3d section than it would be to read the qualification as to time limit into the 1st section. We fully recognize the principle that if an ordinance is susceptible of two interpretations, one of which would make it reasonable and the other not, it is the duty of the courts to adopt the former. But where the ordinance is plain and unambiguous in its terms, and where the only ground for supposing that the words do not express the meaning of the legislative body is that to give them full effect would make it unreasonable and *556oppressive, we take it that it is not within the province of the. court to insert qualifications or conditions which would relieve it of that objection. This would be to amend, not to construe, the ordinance. Taking this view of the 3d section we are compelled to conclude that it is unreasonable and void, and therefore feel justified in withholding expression of opinion upon the other very important questions discussed upon the argument, until a case shall arise in which it is necessary to decide them.

Judgment affirmed.