This case raises the question whether an owner of a city tenement, by having had windows opening towards the land of another, receiving light therefrom for twenty years, without obstruction, acquires an absolute right to the continued enjoyment of that privilege, so that, in case a coterminous proprietor erects a wall or building on his own land so as to obstruct such light, thé owner of the land having such windows can enter and pull down the wall causing such obstruction. It presents this question, because, if decided in the negative, it would be conclusive against the defendant’s justification.

*259Upon this question, we think there has been no direct judicia, decision in this commonwealth. The general rule of the common law, before it was regulated by statute, seems to have been in favor of the affirmative of the question ; holding that uninterrupted enjoyment of air laterally, through and over the land of another, and enjoyed a length of time, created an easement, which could not be disturbed, like that of a right of way, or aqueduct or drain in and over the land of another; though those are distinct in their nature, consisting in actual use and qualified right of occupation in and upon the real property of another, and where such occupation is open and visible, and manifestly adverse to the absolute right of ownership of the servient tenement. But even this general law of England was somewhat modified in regard to the densely packed tenements oí the largest city in the kingdom, by tíie custom of London, which to some extent controlled the general rule of the common law, in regard to that great central city. In many of the states of the Union, the negative of the question has been judicially held; that the enjoyment of light and air in a messuage or building, received through windows laterally, over the vacant territory or lower building of an adjoining proprietor, gives to the owner of such building no right to the continuance of such enjoyment, and imposes no servitude upon an adjoining estate. The same rule is now established, as to the acquisition of any such right, after the passage of the St. of 1852, c. 144. Under these circumstances, we have thought it best not to express an opinion upon this question, when not necessary; and, in looking into the circumstances of the present case, we think they are such that the verdict for the defendant must be set asidez and a new trial had. •

We think the rule is well settled, that, in a city tenement, an easement for light and air, derived from use and enjoyment, or implied grant, can only extend to a reasonable distance, so as to give to the tenement entitled to it such amount of air and light as is reasonably necessary to the comfortable and useful occupation of the tenement for the purposes of habitation or business; not the amount which, under some circumstance s, *260would be agreeable and pleasant, nor the full amount which the tenement has been accustomed to receive; but the amount reasonably necessary. The distance will be determined by a just regard to usage, to the habit and mode of building at the place, a just regard to the rights of ownership of real estate, and, generally, the circumstances of the case. In cities closely built and crowded with inhabitants, the limits must be obviously narrower than in rural districts, where, by general usage, buildings and tenements are more detached from each other. O'Linda v. Lothrop, 21 Pick. 292. The question of reasonableness is a mixed one of fact and law; and where all the facts and circumstances appear, it is a question of law, but in practice it is a question to be passed upon by the jury, under the direction of the court in matter of law.

In the present case, it appears that the defendant erected his tenement at the distance of ten feet from the dividing line between his estate and the plaintiffs’; that he opened windows into his cellar, and two into his lower story, the use of which is not stated; nor is it stated for what uses his building was occupied.

It appears that the plaintiffs erected their wall on their own side of the dividing line, and of course ten feet from the defendant’s tenement. Unless some extraordinary circumstances are shown, of which there is no appearance in the present report, we think the jury should have been instructed, that a wall at such distance was no such illegal obstruction of the defendant’s air and light, at the cellar windows, and windows in his lower story, as to amount to a nuisance, or warrant the defendant in entering the close of the plaintiffs and tearing down their wall.

We suppose, in many large cities, alleys and passages may be found, perhaps some in this, not exceeding ten feet wide, fronting which houses and shops are built on each side.

The court nowhere directed or authorized the jury to take the question into consideration, whether the plaintiffs placed their wall at a reasonable distance from the defendant’s windows ; or whether, after the erection of their wall, the defendant had sufficient light and air for the necessary purposes for which *261Lt was occupied; but directed them to find for the defendant if the plaintiffs deprived him thereof, that is, of such light and air as they are presumed to have granted. We think this referred to that amount of light and air which he enjoyed before the wall was erected, and in legal effect held them hable for any diminution of the enjoyment of that. We think the rule was well laid down by Best, C. J., at nisi prius, in the case of Back v. Stacey, 2 Car. & P. 465, that to constitute an illegal obstruction of the plaintiff’s ancient lights by building, it was not sufficient, that the plaintiff bad less light than before; there must be such a privation of light as would render the occupation of his house uncomfortable, and prevent him, if in trade, from carrying on his business as beneficially as be had previously done. “ In order,” said that eminent judge, “ to give a right of action, there must be a substantial privation of fight.”

Being of opinion that the case was left to the jury without proper direction, as to what was a reasonable distance for the plaintiffs to build from the defendant’s tenement, and the degree and quantity of fight and air to which defendant was entitled; and also in directing them to find for the defendant, if the wall did in any degree diminish the fight and air coming to the defendant’s windows, the judgment of the court is, that the verdict be set aside and a New trial had.