BAM 2 - Seeing and acquiring

The Gemara begins with an assumption that the two cases of 'finding' and 'all mine' are one. Based on this, the Gemara learns that even though 'finding' could have the connotation of just seeing an object, the extra part of the case, 'all mine,' teaches that it is not enough to see an ownerless object for it to be considered yours, rather one must actually pick it up.

Then the Gemara rejects the notion that this is one case and says it is actually two separate cases, one referring to a lost object, and one referring to two people claiming they have bought something.

With this new understanding of the two cases as indeed being separate, do we lose the whole previous thought that taught us that seeing is not enough to acquire? In other words, will it now be enough to look at an object in order to acquire it, being that we don't have any extra case in the Mishna to teach us otherwise?

So I asked the local Rosh Kollel, R' Akiva Teichtal, who gives a daily daf shiur, and he said that they asked the same question in the shiur, and they came out as follows. It is clear that the Torah uses the word מצא - 'finding' to mean actually picking up. Thus, the Torah itself indicates that there is no acquisition until the object is picked up. At the first stage of the Gemara, all we were saying was that the mishna is coming to teach you this - so you don't make a mistake - and think that seeing it would be enough for it to be yours. Even without the mishna coming to tell us this, however, seeing would still not constitute an acquisition, thus when we no longer have the extra words from our mishna, we just don't have the indicator to correct our mistake; but seeing would still not create an acquisition in any event.

BK 96 - Old coins

The Gemara says that in regards to a case where someone stole a new coin, and it got old and turned black while in the posession of the thief, it is considered a significant change and the thief does not return the coin as is, but rather pays the original value of the coin when it was new.

The Gemara says that perhaps you would say that it is not a significant change, because it could be shined again and look new. To this the Gemara says, "מידע ידיע שיחמייהו" - Their age (or blackness) is known.

What does this mean?

בע"ה נ"ל לפרש that when you take an old blackened coin and shine it to look 'new,' no matter how much you shine it, it will still be obvious that this is not a new coin, but rather an old coin that was shined. That being the case, the value of a newly minted coin (in 'mint' condition) is higher than an old and dirty coin, and also higher than an old coin that has been shined to remove the effects of age. Thus, the 'age is known' - i.e. it is clear that it is still an old coin, despite the fact that it has been shined, and therefore one would have to pay the original value of what he stole and would not be able to give back the coin as is.