Metaltelin (movable objects) can only be acquired by lifting up or drawing near the item. They cannot be acquired by paying for them. When a person does this act of Kinyan, of acquiring the item, the buyer takes ownership of it regardless of whether he has paid. He may owe the person money after he acquires it, but he acquires the item through a physical action performed on it. Before a person performs a type of Kinyan, he doesn't own the item even if he did pay for it. Here we'll talk about it in this Mishnah. What if people are trading coins that are being used as payment? Let's say a person has gold coins, as we'll start off by talking about in the Mishnah, and he wants to trade them for silver coins. At what point in time during that transaction is the item considered to be acquired and bought? At what point could you say that a person is buying it? What coin is buying, and what coin is being bought?
The Mishnah says: If you have gold coins that are being traded for silver coins, picking up the gold coins is the point at which the other person acquires the silver coins. When the gold coins are considered to be bought, the silver coins are also considered to be in the other person's possession. They complete the sale when the gold coins are lifted up. But taking the silver coins does not cause the other person to acquire the gold coins. Because when you're dealing with silver coins and gold coins, the gold coins are the more expensive ones. They're much more difficult to find in the shuk (marketplace). The silver coins are considered to be the money here, so picking up the money, acquiring the money, doesn't do anything. Therefore, picking up the silver coins is just dealing with the money part of it. That's why if a person picked up the silver coins to take them for him, he hasn't really given over the acquiring of the gold coins to the other person, and the sale is not complete.
Like we mentioned, the type of coin that's more easily spent or found in the marketplace is considered to be the money, as opposed to the item that's being bought. That's the understanding of this Mishnah so far. Again, basically, what's considered to be the money that's purchasing, and what's considered to be the item that's being purchased? For now, we're saying that the more expensive one, or the one that's more difficult to find in the marketplace, is considered to be the item that's being acquired. The cheaper of the two currencies is considered to be the money that's buying it.
If you have silver and copper coins being traded, the copper coins cause the other person to acquire the silver coins because, when dealing with copper coins, they're considered to be the item that's being bought, and therefore the Kinyan would happen when those are lifted up. But if you lift up the silver coins, they would not cause the other person to acquire the copper coins, because here the silver coins are considered to be the money and the copper coins are considered to be the item that's being bought. The reason here is that, even though technically copper coins are cheaper than silver coins, copper is considered to be a lower-value material than silver. The fact is that silver is accepted everywhere, and copper coins are only accepted in select locations by certain countries. Therefore, since there are people who don't accept copper coins at all, those coins are regarded as the object being bought, and the silver coins are the objects. So here it's not necessarily about the value of the coins, because the silver coin is worth more than the copper coin. Here, it's about what is found more in the marketplace. The silver coins are pretty much accepted everywhere, so they are considered to be the money, and the copper coins are the items being bought.
Next case of the Mishnah: If you have ma'ot ra'ot, bad coins—that means coins that are no longer in circulation, that aren't being used—and they're being traded for good coins that are still in circulation, we consider the bad coins, the ones that are not in circulation, to be the item being bought. The money that's in circulation, the ma'ot hayafot (good coins), is what does the buying. They're the money here. Therefore, if a person picks up the bad coins, he has acquired the good coins, but picking up the good coins does not acquire the bad ones. The good coins here are considered to be the money, and money doesn't execute any transaction here. It is defined by what counts as money. The bad coins, the ones that are not in circulation anymore, cannot possibly be considered money. They automatically become the object because they can't be used as money. Therefore, the good coins, the ones that are in circulation, are considered to be the money. Again, the bad coins are considered to be the item being bought. So here, you have an item that's probably of much less value—the ma'ot ra'ot, the bad coins—relative to the good coins, but still, the good coins are considered to be the money and the bad coins are considered to be the object being bought.
Ha'asimon (un-minted coin) koneh et hamatbea (coin), vehamatbea eino koneh et ha'asimon. If you have a minted coin that you're trading for an un-minted coin, that means it doesn't have the stamp; it's just a piece of metal, the un-minted coin. The asimon doesn't have that seal of the government on it. So you're trading that minted regular coin for an un-minted coin. Taking the un-minted coin would cause the other person to acquire the regular minted coin, because the un-minted coin is considered to be the object being bought here. But if you take the minted coin, that would not cause the other person to acquire the un-minted coin, because the minted coin here is considered to be the money, and lifting up, taking the money, would do nothing for you.
Now, a halacha (Jewish law) about Metaltelin, movable objects: Hametaltelin konin et hamatbea, vehamatbea eino koneh et hametaltelin. When you take the object, you cause the seller to acquire the coins that were being given to him as payment, but the taking of the coins by the seller of the item would not cause the buyer to acquire that movable object. The Mishnah finishes off with another klal. Zeh haklal, this is the rule. Kol hametaltelin konin zeh et zeh. When a person trades one movable object for another, all movable objects acquire one another. As soon as a person takes one movable object, the other person acquires the other object. It doesn't matter where it is or what the situation is; the deal is final, and the transaction has gone through at that point.