Bava Basra, Chapter 4, Mishnah 6. The Mishnah discusses a person who sells his bathhouse and says simply that he is selling the bathhouse, without specifying what is included in the sale. The question the Mishnah comes to clarify is, therefore, what is included in this sale and what remains in the hands of the seller.
The structure of a bathhouse in the times of the Mishnah:
The standard bathhouses in those days were built with three rooms, as three sequential stages:
The first room - where people would converse with one another while dressed in their clothes.
The second room - where they would undress.
The third, innermost room - where the bathing tubs themselves stood, and where they stayed without clothes.
"Hamocher es hamerchatz" - what is not included in the sale:
"Lo machar es hanesarim" - he did not sell the boards. The wooden boards are not included. The Bartenura explains that these boards were used as clothing racks. They did not have hangers like we do today, but rather a sort of pole shaped like a broomstick, upon which clothes could be hung, and it would be placed on the floor leaning against the wall. Since the original owner can easily take them with him when he leaves, they are not included in the sale.
"Ve'es hasafsalim" - and the benches. The seller can take the benches with him as well. The Bartenura cites a different version of the text, reading "sefalim" - basins, which are a sort of bowl or jug meant to hold water for the bathhouse. In any case, the reason is the same: they are very easy to move, and therefore they go with the original owner after the sale of the bathhouse.
"Ve'es havilonos" - and the curtains. These curtains are a sort of screen meant to maintain privacy at the entrance of the bathhouse or between its different sections. Since they can be easily removed, they remain in the possession of the original owner.
"Bizman she'amar lo, hu vechol mah shebesocho - harei kulan mechorin" - when he says to him, it and everything in it, they are all sold. If the seller specified that he is selling the bathhouse and everything inside it, then all of these items - the boards, the benches, and the curtains - are included in the sale along with the bathhouse.
"Bein kach u'vein kach" - either way. Whether he specified that he is selling everything, not just the main structure but also everything inside it, or whether he did not specify - two things are not included in the sale:
"Lo machar lo es hameguros shel mayim" - he did not sell him the water reservoirs. These are the pools of water outside the main bathhouse. The pools and the water inside them remain in the possession of the seller, unless he wishes to sell or rent them out. Even though the water flows from them into the bathhouse, and without them there is no practical way to operate it, they are not considered part of the bathhouse, since the new owner can obtain water for himself in another way.
"Velo es otzros shel eitzim" - and not the storehouses of wood. The same rule applies to the wood storage areas. Even though wood is required to heat the water, if the original owner had a facility for storing wood, neither the wood nor the storage facility itself is sold along with the rest of the bathhouse.
In summary: In this Mishnah we learned that one who sells a bathhouse without specifying, does not sell the boards, the benches, and the curtains, because they are movable and easy to remove. If he specified, "it and everything inside it," they are all sold. However, either way, the water reservoirs and wood storehouses are not included in the sale, even though they serve the operation of the bathhouse.