Glass Bottle

The Glass Bottle is an item that was added in 1.9 Pre-release 2. Glass Bottles are used to brew potions and Splash Potions with various effects. It is possible to pick up water for potions in the 1.9 Pre-Release 3. You can put them in the Brewing Stand; however, potions cannot be created unless they are filled with water. You can put in various things to make different potions, these include potions such as Instant Health.

The bottles also could be filled with a Cauldron; you right-click on a cauldron with a glass bottle in your hand. the bottle will be filled and 1/3 of the water in the cauldron is taken out. To fill the cauldron, you have to right-click with a bucket of water on it. The water in the cauldron moves, but you won't see or hear splashes when you step in it. As of full release Minecraft 1.0.0), you can no longer fill a bucket from a stream unless you use the bucket on the source block (which removes the stream entirely). Therefore you can no longer use a well placed bucket of water to generate an infinite water supply. The use of a cauldron is very expensive as you need to craft both a bucket and the cauldron itself. This uses up ten iron ingots, and a cauldron will not help you in doing anything else.

History
The Glass Bottle was first added in the Beta 1.9 Pre-Release 2. They were given an additional function for picking up water for potions in the Beta 1.9 Pre-Release 3.You need water bottles for making potions.