Mikvaos, Chapter 7, Mishnah 2. This chapter examines water in its various forms and conditions: frozen, altered, or mixed with other substances, and asks in each case whether it still counts as water for the purposes of a mikvah. The Mishnah works through three categories: substances that raise the mikvah's measure and never disqualify it, substances that disqualify the mikvah yet cannot be counted toward its measure, and substances that neither raise nor disqualify. Our mishnah takes up the second and third of these.
Poslin velo Ma'alin
"Eilu poslin velo ma'alin." The liquids about to be listed hold the halachic standing of water in one respect only: three lugin of them, once they have passed through a vessel and become she'uvim, will ruin a mikvah that has not yet gathered its forty se'ah of rainwater. Yet for the purpose of completing that shiur they contribute nothing whatsoever.
First on the list: "Hamayim," drawn water, "bein temeiyim bein tehorim," whether the water is tamei or tahor. That distinction makes no difference here. Drawn water that enters the mikvah renders it pasul, and it certainly does not count toward completing the shiur.
The Mishnah continues with three more liquids:
- "Mei kevashim," the liquid in which vegetables have been left to pickle over an extended period.
- "Umei shelakos," the liquid in which vegetables have been boiled.
- "Vehatemed," water added to the pulp and skins left behind after grapes have been pressed for wine, "ad shelo hechmitz," so long as it has not yet turned sour and acquired the character of wine.
All of these still carry the halachic status of water. Therefore, if they were collected in a vessel before reaching the mikvah, they disqualify it with the measure of three lugin.
The Case of Poslin velo Ma'alin
"Keitzad poslin velo ma'alin?" What is the case in which these liquids invalidate the mikvah and yet do not raise its measure?
"Mikvah sheyeish bah" a quantity of "arba'im se'ah chaser kortov": the pool holds its forty se'ah apart from one kortov, a minute shortfall (a kortov being the sixty fourth part of a log). "Venaful meihem kortov letochah," a kortov of one of these liquids, the pickling water, the cooking water or the temed, drops in, "kesheheim she'uvim," in a state of having already been drawn. The ruling is "lo he'eluhu": the shiur was not completed by them, tiny as the deficiency was. Moreover, "uposloi bishlosha lugin" teaches that three lugin of such liquid entering the pool render it pasul outright.
Lo Ma'alin velo Poslin
Now the Mishnah turns to the third category. "Aval she'ar mashkin," all other liquids that are not water, and specifically:
- "Umei peiros," liquids pressed from fruit.
- "Vehatzir," the brine that drips off fish being salted.
- "Vehamuryas," the fatty oil rendered out of fish.
- "Vehatemed mishe'hechmitz," that same liquid drawn from pressed grape pulp, but now after it has soured and taken on the character of wine.
None of these are considered water any longer. They have lost their identity as water entirely. Consequently, "pe'amim ma'alin ufe'amim she'einan ma'alin," there are circumstances in which they in effect raise the measure of the mikvah and circumstances in which they do not.
"Keitzad?" The Mishnah explains when each is so.
"Mikvah sheyeish bah" a quantity of "arba'im se'ah chaser achas": the pool contains thirty nine se'ah, one short of the required forty. "Nafal letochah se'ah meihen," a se'ah of one of these substances falls in. The ruling is "lo he'elu": the shiur remains incomplete, because a liquid that is no longer water cannot allow us to say that the pool holds forty se'ah of rainwater.
"Hayah bah arba'im se'ah," where the pool already contained the full forty se'ah, "nosan se'ah," a se'ah of such liquid was put in, grape juice, apple juice or anything similar, "venotal se'ah," and afterward a se'ah was drawn off, the halachah is "harei zeh kasher." The mikvah keeps its validity. The liquid that entered was nullified in the mass of the mikvah's water, so we continue to regard the forty se'ah as intact, notwithstanding that an entire se'ah has since been taken away.