Opinion of the Court. error without even an attempt on its part to comply with the requirements of the statute law. The certainty of compensation is the primary requisite to the appropriation of lands for public use under the right of eminent domain. Potter's Dwarris on Statutes 390; Cooley's Const. Lim. 699. That compensation must be not only certain but provided for prior to or pending the proceedings, see 2 Kent Com. 339; Bloodgood v. Mohawk & Hudson Railroad, 18 Wend. 17; S. C. 31 Am. Dec. 313; Bonaparte v. Camden & Amboy Railroad, 1 Baldwin C. C. 205; Garrison v. City of New York, 21 Wall. 196, 204; Potter's Dwarris Statutes 387-392. The statutes of Colorado provide either for payment before the taking possession, or in case of disagreement between the owner and the condemning party, for a deposit in court "pending the ascertainment of damages." No payment was made in this case, and no attempt was made to deposit in court an amount which would indemnify plaintiff in error. Mr. C. S. Thomas for defendant in error. MR. CHIEF JUSTICE FULLER, after stating the case, delivered the opinion of the court. Upon the conceded facts, unless the plaintiff in error was entitled to be compensated for the school-house in question, the instruction limiting the recovery to three thousand dollars was correct, and the judgment must be affirmed. The constitution of the State of Colorado provides "that no person shall be deprived of life, liberty or property, without due process of law;" and "that private property shall not be taken or damaged, for public or private use, without just compensation." Art. II. §§ 25, 15, Gen. Stat. Col. 1883, 34, 35; 1 Charters and Constitutions, 221, 222. Did the just compensation thus secured to the owner of property taken in the exercise of the power of eminent domain, include in this instance payment to the plaintiff in error for the improvements made by the school district in order to carry Opinion of the Court. out the specific use and purpose for which the land was required? Could plaintiff in error properly insist that the loss of the school-house was an injury which he sustained by reason of the taking? The argument is that the moment the school-house was completed it belonged to the owner of the land by operation of law, and therefore that he was entitled to be recompensed for it upon condemnation. The maxim quicquid plantatur solo, solo cedit, is not of universal application. Structures for the purposes of trade or manufacture, and not intended to become irrevocably part of the realty, are not within the rule, Van Ness v. Pacard, 2 Pet. 137; nor is it applicable where they are erected under agreement or by consent, the presumption not arising that the builder intended to transfer his own improvements to the owner. And courts of equity, in accord with the principles of the civil law, when their aid is sought by the real owner, compel him to make allowance for permanent improvements made bona fide by a party lawfully in possession under a defective title. Story Eq. Jur. § 1237. The civil law recognized the principle of reimbursing to the bona fide possessor the expense of his improvements if he was removed from his possession by the legal owner, by allowing him the increase in the value of the land created thereby. And the betterment laws of the several states proceed upon that equitable view. The right of recovery, where the occupant in good faith believes himself to be the owner, is declared to stand upon a principle of natural justice and equity, and such laws are held not to be unconstitutional as impairing vested rights, since they adjust the equities of the parties as nearly as possible according to natural justice; and in its application as a shield of protection, the term "vested rights" is not used in any narrow sense, but as implying a vested interest of which the individual cannot be deprived arbitrarily without injustice. The general welfare and public policy must be regarded, and the equal and impartial protection of the interests of all. Cooley Cons. Lim. *356, *386. But if the entry upon land is a naked trespass, buildings permanently attached to the soil become the property of the VOL. CXXXIII-36 Opinion of the Court. owner of the latter. The trespasser can acquire no rights by his tortious acts. The Circuit Court was not dealing with an action of ejectment or trespass, but simply with a proceeding in the exercise of the right of eminent domain. That right is the offspring of political necessity, and is inseparable from sovereignty unless denied to it by its fundamental law. It cannot be exercised except upon condition that just compensation shall be made to the owner, and it is the duty of the State, in the conduct of the inquest by which the compensation is ascertained, to see that it is just, not merely to the individual whose property is taken, but to the public which is to pay for it. Garrison v. New York, 21 Wall. 196, 204; Kohl v. United States, 91 U. S. 367, 371. The occupancy here was in no respect for a private purpose or pecuniary gain, but strictly and wholly for the public use. There could be no presumption that this public agent intended to confer public property upon a private individual, nor were the circumstances such as to impart the character of wilful trespass to the entry by the district, or impose liability to the forfeiture of improvements made in discharge of its public duty. It is among the agreed facts in the case that the premises. appropriated were necessary for the schools and were taken for that public use; that though the district had knowledge of the issuing of a patent covering the property, yet it purchased the adverse title of the party then in possession, believing it to be better than the patent title, and upon the advice of reputable counsel, who had, on investigation, reported against the validity of the patent and in favor of the validity of the title purchased, and paid thirty-five hundred dollars, which was five hundred dollars more than the actual value, without the building, was admitted to be when the trial took place; and that, notwithstanding notice that it was proceeding at its peril, it erected the building in reliance upon such belief that it had the better title. The only legitimate inference from these facts is that the district acted throughout in good faith, as the opposite of fraud and bad faith, and, although it may have been wholly mistaken, the intention guided the Opinion of the Court. entry and fixed its character, and it cannot be held to have been such a trespass as to justify the claim that the school building, erected in similar good faith, so became part and parcel of the land as to entitle the owner to recover its value. Plaintiff in error knew when he obtained the title that the land was in necessary use by the public for a purely public purpose, and that no intention of parting with the structures could be imputed; and no notice of what his grantor or himself intended to insist on could destroy the good faith in fact, which the conceded belief of the district imparted to its conduct. In Wright'v. Mattison, 18 How. 50, this court, in considering a statute of the State of Illinois in protection of persons "in the actual possession of lands or tenements under claim. and color of title made in good faith," reiterated the rule that color of title is matter of law, but good faith in the party claiming under such color is purely a question of fact; and held that, while defects in the title might not be urged against it as destroying color, they might have an important and legitimate influence in showing a want of confidence and good faith in the mind of the vendee, if they were known to him, and he therefore believed the title to be fraudulent and void. The court approved of the opinion of the Supreme Court of Illinois in Woodward v. Blanchard, 16 Illinois, 424, in which it was said by Scates, C. J., that "the state of mind of the party in relation to such title was an existing truth which must be ascertained and found as a fact in the cause. Many independent facts and surrounding circumstances may be admissible in evidence, and legitimately considered as establishing or impeaching the state of mind in its good faith, honest belief or trust in, or dependence upon such title." And this language was quoted by the court from that opinion: "Good faith is doubtless used here in its popular sense, as the actual, existing state of the mind; whether so from ignorance, scepticism, sophistry, delusion, fanaticism, or imbecility, and without regard to what it should be from given legal standards of law or reason.' Ewing v. Burnet, 11 Pet. 41; Pillow v. Roberts, 13 How. 472. As remarked by Beckwith, J., in McCagg v. Heacock, 34 Illinois, Opinion of the Court. 476, 479: "The good faith required by the statute, in the creation or acquisition of color of title, is a freedom from a design to defraud the person having the better title;" and "the knowledge of an adverse claim to, or lien upon property, does not, of itself, indicate bad faith in a purchaser, and is not even evidence of it, unless accompanied by some improper means to defeat such claim or lien." We are of opinion that plaintiff in error could not successfully contend that the school district should be treated as a naked trespasser. And as the actual value of the land at the time of the trial must have included whatever increase may have enured by reason of its adaptability to school purposes and every other element entering into its cash or market value, as tested by its capacity for any and all uses, it follows that the true criterion of recovery was adopted. It is not denied that the school district, when it filed its petition, was entitled to acquire the property in the exercise of the power of eminent domain, but it is said that it could not do so prior to February 13, 1883, the date of the passage of an act rendering such action on its part lawful. Sess. Laws, Colorado, 1883, 263; Gen. St. § 3044, 893. But we cannot perceive that this affects the precise question before us. Inability to condemn indicates that possession was not taken with the view of proceedings to that end, but that is conceded on the other ground, that the school district believed that it had the better title and erected its building accordingly. When it came to possess and exercise the power, the inquiry was limited to such compensation as was just and did not embrace remote or speculative damages, or payment for injuries not properly susceptible of being claimed to have been sustained. It was ruled in Secombe v. Railroad Company, 23 Wall. 108, 118, in relation to the taking of private property by a railroad company under the power of eminent domain, that "prior occupation without authority of law would not preclude the company from taking subsequent measures authorized by law to condemn the land for their use. If the company occupied the land before condemnation without the consent of the |