How many gauge cocks does a boiler have if it has two water glasses on the same horizontal line?

A boiler equipped with two water glasses on the same horizontal line should have two gauge cocks, one for each water glass. Gauge cocks are essential because they allow operators to check the water level in the boiler by isolating the water glass from the boiler pressure, ensuring accuracy in readings. Each water glass needs its own gauge cock to function properly, as they provide a means to drain or isolate each glass for maintenance or verification purposes. Therefore, having two water glasses implies the necessity for two corresponding gauge cocks to ensure both can be independently checked and managed.