Bell jar n. (Phys.) A glass vessel, varying in size, open at the bottom and closed at the top like a bell, and having a knob or handle at the top for lifting it. It is used for a great variety of purposes; as, with the air pump, and for holding gases, also for keeping the dust from articles exposed to view.
... anhydrous sulphates of iron, &c., which are not readily dissolved when afterwards diluted. The use of sulphuric acid in assaying is (for these reasons) to be avoided. Its chief use is as a drying agent, since it has a strong affinity for water. Air under a bell jar may be kept dry by means of a basin of sulphuric acid, and gases bubbled through it are ... — A Textbook of Assaying: For the Use of Those Connected with Mines. • Cornelius Beringer and John Jacob Beringer
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