The Adventure of Link Magic Containers
A total of four Magic Containers can be found all over Hyrule. They will increase your overall magic meter a little each time you find one.

Western Hyrule

Magic Container #1 North Castle Area
 - Just southwest of North Castle is a cave. However, you cannot see anything in there unless you have gotten the Candle from Parapa Palace. There are enemies inside that are invisible if you don't have it. Once you reach the end you'll find a Magic Container.

Magic Container #2 Spectacle Rock
 - After you get the Hammer at Spectacle Rock, come out of the hole you got it in and look to your left. There is a boulder, and it's breakable with your new Hammer. Break it and jump down the hole. You'll fall down right next to the Magic Container.

Eastern Hyrule

Magic Container #3 Maze Island
 - Explore Maze Island and eventually you'll fall down an invisible hole on the west side of the island. You'll fall down a hole, and the Magic Container will be right with you when you land.

Magic Container #4 New Kasuto
 - Make your way to the Hidden Town of Kasuto. This town resides in a small forest after venturing through a cave in Eastern Hyrule. You must chop down the certain brush to get to it. Once you found the town, talk to an old lady in a blue dress. You then follow her into the house and in the basement you will find the last Magic Container.