A Hairsbreadth Is Enough

About This Talk

Mikvaot 8-10 moves from how bodies of water join, through a six rung ladder of water sources, to what doubt does and does not undo. Chapter eight rules that any water in contact with a mikveh is the mikveh itself: cavities beside the opening and the footprints animals press into the edge may be used if they share a point of contact as large as the mouthpiece of a drinking pouch, while cavities and crevices at the side need only the slightest contact; a needle left on the step regains purity when a wave is raised over it; a wall cracked vertically joins two pools outright if together they hold 40 se'ah, a horizontal crack needs the full measure, and water standing above the wall joins them if a layer as thin as a garlic peel spans that width; a hidden reservoir behind sturdy ground needs the full measure, but behind ground that will not last, any contact whatsoever suffices. The measure itself is defined as a circle in which two average fingers can be rotated, not the thumb but the first two on the palm, anything present in the hole reduces it even something the water itself produced, and an unresolved doubt about the measure is decided stringently because the primary obligation to immerse is Scriptural. Pools purify each other through an earthenware or lead pipe where the waters intermingle by a hairsbreadth, yet a current running down a wadi through three catchment basins of twenty, forty and twenty se'ah joins none of them, since flowing water does not join mikveot unless it collects in one place. Soft mud a cow would drink is measured into the forty, red worms and the eye of a giant fish are fit, and in a pool holding exactly forty the second of two successive immersers stays impure because the first carried water out on his body, unless a sponge still touching the surface keeps the waters intermingled; a large pot must be lowered by its opening and raised by its base so the water inside does not become drawn. Chapter nine ranks six categories, each superior to the last: water collected in a pit, rainwater still flowing while the mountains gush, forty undrawn se'ah in which all may immerse except a male zav, a spring with drawn water added, a spring whose water has gone bitter or salty, and a spring of living water in which alone a male zav may immerse and from which alone water is taken for one afflicted with tzara'at and for sanctifying the water for the ashes of the red heifer. The differences are stated flatly: a mikveh needs forty se'ah and must stand collected, a spring needs no measure at all and purifies while it flows. All the seas purify yet serve for none of those three; water flowing from a spring extends the spring while water that merely drips is only a mikveh; a conduit must be an article not susceptible to impurity, though the green outer shell of a fresh nut may turn the flow because it is not a container; rainwater cascading down a hill is unfit while it runs and fit once containers are set as walls to collect forty se'ah; and a wave purifies when both its ends touch the earth, never in the air and never at its crest. Chapter ten turns to doubt and splits it in two. Doubt about drawn water is resolved leniently: a pool found full where it was left empty is fit, two pools where three lugim fell into one unknown leave the valid one valid because there is a factor to rely on, both are disqualified if neither held forty, and a pipe beside a mill disqualifies unless the pool holds a majority of acceptable water. Pools in the lands of the nations and inside the gates of a city are presumed drawn, those outside the gates presumed rainwater. Doubt about the person goes the other way: whether he immersed, whether the pool held forty, or in which of two pools he immersed, he remains impure, because an impure person is presumed impure until a proper immersion is certain, and a pool later measured short renders everything immersed in it impure retroactively, except where the impurity was light and rabbinic in origin.