There are many related approaches which can be used to carry out chemistry under modified atmospheres. This page provides a summary of the different techniques and provides links to the individual guides.
Exclusion of water only
Drying tubes form a barrier between the atmosphere and the reaction which reduces the amount of water present. The widespread use of balloons has pretty much eliminated the use of drying tubes.
Can be filled with a range of gases:
Inert gases such as nitrogen or argon to eliminate water
Gases required in a reaction such as hydrogen or oxygen
Provides a simple and economic means to reduce the presence of water and air during a reaction, but not in workup steps. Often combined with oven dried glassware to further minimise the presence of water. Requires minimal changes to reaction techniques. Not suitable for reactions which liberate gas.