It is well established that a gas company whose mains and pipes run beneath the surface of roads and streets is, for rating purposes, in occupation of the land where they lie. The same principle is applied to the mains and pipes of a water works. The earliest cases of gas mains of which I am aware are R. v. Birmingham Gas-Light and Coke Co. [1] and R. v. Brighton Gas Light and Coke Co. [2] . To my mind it is pedantic logic-chopping to suggest that because a pipe is hollow the space of the earth which it occupies when embedded in the soil is not "land". A basement, a subway, a cellar or a tunnel can be the subject of occupation and ownership. It can be held for an estate in fee simple; for a parcel of land can be defined by horizontal or by vertical boundaries: see Metropolitan Railway Co. v. Fowler [3] , and the cases mentioned by Roper J. in Resumed Properties Department v. Sydney Municipal Council [4] . But to say that a space below the surface of the earth may be a freehold is not to say that every space below the surface of the earth is the freehold of the person who has the use of it. And to say that the space which a gas main or pipe occupies is "land" is not to say that the gas company has an estate in that land. All that the decisions about rating really establish is that while a gas-pipe is embedded in the soil the land where it is is in the occupation of the gas company. It is important to remember that in England rating law was, indeed still is, derived ultimately from the statute for the poor rate, 43 Eliz. I c. 2, modified and added to by later enactments. The criterion of liability there is ratable occupation. But in New South Wales it is now the owner, not the occupier, who is primarily liable for the local government rate. This was not always so. Under the Municipalities Act, 1897 N.S.W. the criterion was ratable occupation, as in England. It was in that situation that this Court decided in Borough of Glebe v. Lukey [5] , that a gas company having placed mains and pipes under a street pursuant to statutory powers was the occupier of land. I may interpolate here that gas companies in New South Wales are not now ratable as land owners or occupiers in respect of pipes under roads. They are now subject to a special provision, s. 171 of the Local Government Act. The history of this was summarized by Sugerman J. in Australian Gas Light Co. v. Annandale Municipal Council [6] . The section provides that where any rail, pipe, wire, etc. has been placed under or over any public street the local council may make "a fair annual charge upon the person for the time being in possession, occupation, or enjoyment of such rail, pipe, wire ". This provision clearly carries no implication that the possession, occupation or enjoyment of gas-pipes by a gas company is to be regarded as an estate in land. On general principle the exercise by the respondent of its statutory right to occupy part of a street vested in the council by placing its mains and pipes there did not, it seems to me, give it a corporeal hereditament. The hereditament of the whole of the street is in my opinion in the council. It could direct the gas company to alter the mains and pipes and their accessories - which I take it would include moving them and relaying them elsewhere in the street. The word "hereditament" and the word "estate" both appear to me inapt for the respondent's mere right of occupation. But it was said, if it was not a corporeal hereditament, it was an easement. And an easement is now regarded as a species of incorporeal hereditament although in Coke's time the name hereditament was denied it: see Challis, Law of Real Property, 3rd ed. (1911) (by Sweet), pp. 54, 55. But this can only be said of a true easement, for it is because the dominant tenement descends to the heir that the rights over the servient tenement are an hereditament. The gas company has however no true easement; for there is no true dominant tenement unless it be said to be the gas works. However there is here an analogy to an easement as known to the common law; and if it be necessary to given some name to the right in relation to land which the respondent enjoyed, it was what is nowadays very often called a "statutory easement" e.g., in the article "Statutory Easements" in The Conveyancer, vol. 20 (1956), p. 208: see too Gale on Easements, 13th ed. (1959), p. 4 (n). Such so-called easements can, as is said in Halsbury's Laws of England, 3rd ed., vol. 12, p. 530, be "appurtenant only to some enterprise or even irrespective of any dominant tenement at all". They may sometimes be called easements in Acts of Parliament. It is now too late in the day for lawyers to complain as in 1916 that great real property lawyer Charles Sweet complained of the loose and inaccurate use of the term: see the Law Quarterly Review, vol. 32, p. 70. Scrutton L.J. said in Taff Vale Railway Co. v. Cardiff Railway Co. [1] , "it is clear that Parliament can confer certain rights not previously known to the law, and can call them by what names it pleases, however previously inappropriate". But it need not give them any name. If it does not, there is no need for lawyers to insist on finding an old name for them, when they are in fact sui generis. I respectfully accept and need not repeat what Lord Evershed said in Newcastle-under-Lyme Corporation v. Wolstanton, Ltd. [1] . The North Shore Gas Act of 1875 gave no name to the rights it created. However the respondent hopes that by putting some known label on them they will be shown to create an "estate" or "interest" in "land" within the meaning of the Public Works Act. If one were to resort to Roman law terms, the right to have pipes run under public roads would be described as a ius in re aliena: it would be a servitude, but of a personal, not a praedial, character. But Lord St. Leonards' statement that "the category of servitude and easements must alter and expand with the changes that take place in the circumstances of mankind" (Dyce v. Lady James Hay [2] ) must be read bearing in mind that English law does not, apart from statute, recognize an easement in gross. It is thus, I think, fallacious to say that because the privilege of the respondent can be called, or miscalled, an "easement" the rights of the gas company are an incorporeal hereditament and therefore an estate or interest in land.