Meanings of heated under in English

If this incrustation be heated under the reducing flame, it disappears with a blue flame.

The blue sensitive variety if heated under water has its sensitiveness perceptibly increased, while the other is not changed by such treatment.

And of course we all recognise it as a lonesome wailing presence in any half-decent cowboy picture where beans are heated under the stars.

But if it was heated under pressure it changed into another and a new kind of resin that was hard, inelastic, unplastic, infusible and insoluble.

The crystals are mixed with 2 l. of 15 per cent hydrochloric acid and heated under a reflux condenser for two to three hours.

1.19) and 15 g. of glacial acetic acid are heated under a reflux condenser for ten hours, in a 2-l. flask.