[bm40a. We begin with the first mishna on the page.
As we will be discussing specific quantities of produce, a brief mention of the relevant standard dry measures might be useful, bearing in mind that they varied somewhat from place to place, and their moder equivalents are only approximate:
1 Kav about 2.2 liters or 2.33 quarts 1 Se'ah = 6 Kabin about 13.2 liters or 14 quarts 1 Kor = 30 Se'in about 0.4 m^3 or 13 bushels]
Mishna: If one has deposited produce, [when he returns the produce] he deducts the expected depletion. [The expected depletion is] 9 half-kabim from a kor [2.5%] of wheat or rice, 9 kabim from a kor [5%] of barley and millet, and 3 se'ahs from a kor (10%) of spelt and flax seed. All is proportional to the measure [amount deposited] and the time [duration of the deposit]. [Rashi: The expected depletions listed are annualized.]
R. Yohanan ben Nuri said: What do the mice [who cause the depletion] care about the amount deposited? They eat the same amount, whether from a large quantity or a small quantity. Instead, he [the custodian] deducts the depletion for only one kor.
R. Yehuda says: If the quantity was large, he does not deduct for depletion, for it increases in volume. [Rashi: It absorbs moisture and swells.]
Gemara: [The gemara begins with a practical question:] But rice decreases more [than the 2.5% specified in the mishna]?
[The gemara answers:] Rabbah bar bar Chana said in the name of R. Yohanan: We learned this with respect to peeled rice [which is not depleted at much as is unpeeeld rice].
[Our Mishna:] 3 se'ahs from a kor (10%) of spelt and flax seed. R. Yohanan said in the name of R. Hiyya: We learned this regarding flaxseed in its husk. We also learned in a b'raita: [The expected rate of depletion of] spelt, flaxseed in its husk, and unpeeled rice in 3 se'ahs to a kor (10%).
[Our mishna:] All is proportional to the measure ...
[A b'raita: The expected depletion is] the same for every kor, and for every year [i.e., a certain percent per kor per year].
[Our mishna:] R. Yohanan ben Nuri said [that the mice eat the same amount regardless of the amount stored, so that the amount stored should not affect the expected depletion].
A b'raita [that gives the Rabbi's response to R. Yohanan ben Nuri]: They said to R. Yohanan: Much is ruined and much is scattered [i.e., the depletion _does_ depend on the amount deposited].
A b'raita: When does this apply? When he (the custodian) mixed (the deposited produce) with his own. But if he had set aside a corner (for the deposited produce), he says to the owner "Here, this is your's" [without any adjustment for depletion].
But what if he did mix in his produce? We can determine how much was his [and calculate the proportional depletion, and not rely on a standard depletion rate]?
We are dealing with a case in which the custodian took some of the produce for himself [so that he cannot calculate actual depletion, and must rely on the standard].
So let him see how much he took for himself [and he can still calculate the actual depletion]!
He doesn't know how much he took for himself [so we must rely on the standard depletion rates].
[Our mishna had cited R. Yehuda's position, that if the custodian had been entrusted with a large quantity of grain, he does not deduct anything for expected depletion, because the natural expansion compensates for the natural depletion.]
[Citing our mishna:] R. Yehuda said: If it was ...
How much is a large quantity? Rabba bar bar Hana said in the name of R. Yohanan: Ten kors [about 4 cubic meters or 130 bushels]. We also learned this in a b'raita: How much is a large quantity? Ten kors.
[The b'raita below refers to the fact that granaries and private homes used measures with the same name but different capacities. A granary kor was larger than a private home's kor.]
A b'raita teacher taught before Rav Nachman: Under what circumstances does it [the mishna's ruling on deductions for expected depletion] apply? When he (the owner) measured it from his granary, and he (the custodian) returned it from _his_ granary. But if he (the owner) measured it from his granary and he (the custodian) returned it from his house, he does not deduct for depletion because of the increase. [If the owner deposited 10 granary-kors, and the custodian returned 10 private-house kors {which are smaller}, the decrease in the quantity returned is equivalent to the expected depletion, and no additional adjustment for depletion should be made.]
Rav Nachman said: Are we dealing with fools who give produce in large measures and take it back in small measures? Perhaps [the b'raita's "from the granary" refers to] "in the season of the granary." [Grain was normally stored in the granary after being dried, so that the b'raita should be understood as:] When does this ruling apply? When he (the owner) measured it in the season of the granary, and he (the custodian) returned it in the season of the granary [when moisture levels -- and thus volume -- were the same]. But if he (the owner) measured it out in the season of the granary and he (the custodian) returned it in the rainy season, he does not deduct for depletion because it expands [i.e., the expansion of the grain compensates for the depletion by rodents].
Rav Pappa said to Abbaye: If so [if there is so much expansion in the rainy season], it should burst the casks [used for storage of grain]!
[The gemara answers:] There was, in fact, a case in which the barrel burst. Or else, [they do not burst] because of the pressure [Rashi: the grain is packed tightly, and there is no absorbtion of humidity, and thus no expansion].
[We are at the second mishna on 40a. Our previous mishna had discussed expected depletion of grains; we now move to the issue of the expected depletion of wine and oil.]
[Only two liquid measures are referred to explicitly here: "log" and "kuz", but we will take the opportunity to list two larger measures as well.
"bat" or "baita" (approximately 40 liters or 10 gallons). "hin" = 1/6 of a "bat" (approx. 6.7 liters or 1.7 gallons) "log" = 1/12 of a "hin" (approx. 560 cc or 1.2 pints) "kuz" (also referred to as "rova") = 1/4 of a log, (the capacity of a small coffee cup or large wine glass).]
Mishna: He (the custodian) deducts a sixth of wine [Rashi: the wine is absorbed into the earthenware casks]. R. Yehuda says a fifth. [As with the produce in the preceding mishnah, this refers to the case that the depositors' wine is not set aside, but is kept together with that of the custodian.]
He deducts three logs of oil from each hundred: a log and a half for sediment, and a log and a half for absorption. If the oil was refined, he does not deduct for sediment, and if the casks were old he does not deduct for absorption. [Used oil casks are presumed to be saturated with oil, and would not absorb any of the new oil.]
R. Yehuda says: [The same rule applies to the sale of oil] If he sold refined oil to his fellow over the entire year [i.e., there is a contract that calls for delivery of oil throughout the year], he (the purchaser) accepts a log and a half of sediment for every hundred logs.
[Presumably, the oil is sitting in casks, and the sediment has collected at the bottom. The contract did not specify refined oil, but the seller takes oil from the top, without any sediment. When the barrel is lmost empty, most of what is left is the cask. Since the contract did not specify sediment-free refined oil, the purchaser must accept that last bit of sediment, or - if he does not want it - must take a loss of a log and a half on each 100 logs that he purchases.]
Gemara: They (the anonymous Rabbis of the mishna and R. Yehuda) do not disagree (on the depletion allowance for wine); one reports his local practice and one reports his local practice. In the location of this master (the Rabbis of the mishna), they coated the inside of the cask with wax, which does not absorb much [leading to the one-sixth depletion allowance]; in the location of the other master (R. Yehuda), they coated the inside of the casks with pitch, which asbsorbs more [leading to the one-fifth depletion allowance]. Alternatively (we can attribute the difference to differences in the) clay (used to make the casks). This (clay, used in R. Yehuda's locale) absorbs a lot, and that (clay used in the Rabbis' locale) does not absorb much.
[Our mishna referred to R. Yehuda, a mishnaic tanna. The next incident refers to Rav Yehuda, an amora. The distinction between the R. (Rabbi) and Rav is critical here. Note that, in the discussion below, a kuz is a measure of liquid volume (see above), and a zuz is a unit of currency, as in the Had Gadya goat purchased for two zuzim.]
In Rav Yehuda's town, they [the vintners] would pour 48 kuz [i.e. 12 log or 1 hin] of wine into a cask and sell it for 6 zuz. Rav Yehuda sold the wine in 6-kuz batches for a zuz each. [According to Rashi, Rav Yehuda owned a wine-shop. Rabbenu Hananel says that Rav Yehuda did not sell wine, but regulated the retail sales of wine in his town.]
Subtract 36 kuz [of the total of 48] for 6 [the 6 zuz that was paid for the wine], and you are left with 12 kuz. Subtract 8 kuz which is a sixth [the depletion allowance set by the Rabbis in the mishna], and he is left with a profit of 4 kuz.
[The gemara asks:] But did not Shmuel (Rav Yehuda's mentor) say that one who profits should not profit more than a sixth? [Why did Rav Yehuda only take (or - according to Rabbenu Hananel - allow the retailers to take) 4 of 48 when he could have taken 8 out of 48?]
[The gemara answers:] There is the cask and the sediment. [After selling the wine, Rav Yehuda (or the retailer) was left not only with 4 kuz of wine, but also with the cask and the sediment, which were also of value, and had to be included in the calculation of profit.]
[The gemara asks:] If so, he is left with a profit of more than a sixth?
[The gemara answers:] There is (the value of) his (the person selling) labor, and the wages of the barzanaita [Rashi: either a person who publicizes the availability of the wine, or an expert at making holes in clay vessels for the spigot.]
[The former reading is based on the possibility that the "bet" in "barzanaita" is a "typo" for "kaf". In Hebrew, "karoz" is a herald or announcer, and "karzanaita" would be its Aramaic equivalent. The latter reading is a straightforward extension of "berez", a spigot or faucet.]
[We end at the end of the fifth line of bm40b.]