The facts are stated in the opinion of the presiding justice. I am not convinced, however, that the rights given to the Safety Institute by the instrument were legally given. In the opinion the rights given are called a revocable license. If it be meant revocable at will, I do not so read the paper. The rights given may be revoked by the city for non-compliance with the conditions imposed, or if the property shall be required for other park purposes. This does not give to the city the power to revoke at will, but after investment of $50,000 in the repair of the building the Safety Institute could require proof before a court or jury that the property was required for other park purposes before its rights were taken away.
Again the power of revocation given is incumbered by the moral obligation to permit for the ten-year period prescribed in the instrument the use of the building upon which the Safety Institute expends $50,000 for repair. So that in practical effect the instrument gives to the Safety Institute the use of this park building for ten years unless to meet some *175very cogent demand for its use for park purposes or unless the Safety Institute fails to perform the conditions specified.
The opinion further says: “We put our affirmance of the order appealed from upon the specific ground that all that is provided for in the written agreement sought to be declared null and void is the improvement of an old building now standing in the park and its use after improvement as a museum for the exhibition of safety and sanitary appliances for the education of the public under a revocable license in which the interests of the city are minutely safeguarded and by which no open park space is invaded or encroached upon.” The court then is not willing to hold that the exhibition by the' Safety Institute is a park purpose or incidental thereto. If it were the city might authorize the erection of a new building therefor. That this purpose of the Safety Institute is not a park purpose seems clear. All definitions of parks involve the idea of open air exercise, entertainment and enjoyment. All buildings are excluded except such as are necessary or incidental to such open air use. It is far from accurate to say that the study of safety devices is in any way incidental to such use. It cannot give legality to this instrument that the purpose of the Safety Institute be educational or for the public good. Neither of these purposes authorizes the city to surrender to it any part of the public parks. Could you permit the use of this building for a public school? For a fire engine station? For a public hospital? I think clearly not. The city holds this land for a park and no other use thereof is permitted except by act of the Legislature. The Metropolitan Museum of Art with its enormous educational value occupies park space only through special legislative permission. (See Greater N. Y. Charter [Laws of 1901, chap. 466], § 621.)
The question is here squarely presented whether the city with legislative permission to use this land only for park purposes may permit the use of a building thereon, even temporarily, for any other purpose. No such express power is given. None I think is implied. If the city have such power why not to a corporation organized for private gain as well as for a public purpose? Must the corporation be educational or merely philanthropic? The limit of such power is nowhere defined and to hold that such power exists would present *176innumerable questions as to the proper recipients thereof. Moreover, such a holding would be most dangerous, because of the possibilities of its misuse. The old Mount St. Vincent restaurant is upon park land. May its use, though temporary, be permitted to some other corporation with purposes foreign to park use upon like terms? The Claremont restaurant is upon park land. If that should be abandoned as a restaurant may its use be even temporarily permitted to still some other such corporation upon like terms? The harm to the city in the permission here given may be slight, but as a precedent the ruling is, I think, pregnant with mischief. If there be no need of. this building at present for park purposes it should either be destroyed or held until its use is sought for some purpose incidental to the park use. The park space in New York is already too spare. The courts should jealously guard even slight encroachments lest they be made precedents for greater encroachments hereafter.
In my judgment the order should be reversed and the injunction granted.
Judgment and order affirmed, with costs.