SYMBOLISM OF CHAMBER OF REFLECTION

Although the impact of the chamber’s furniture must of necessity be personal, the symbolism relates to hermetic and alchemical correspondences. The chamber itself is symbolic of a cave, introducing the candidate to the alchemical element of earth. (He will meet the others in the temple.) The skull (often with crossed bones) is an obvious symbol of mortality, and coupled with the hourglass, points to the brevity of mortal existence. Bread and water indicate simplicity. The rooster symbolises the alchemical principle of mercury, which partnered with the salt and sulphur, symbolise faith, hope and charity. “V.I.T.R.I.O.L.” or vitriol (sulphuric acid) is interpreted as “visita interiora terrae, rectificandoque, invenies occultum lapidem“, or “visit the interior of the earth, and purifying it, you will find the hidden stone.” This is another way of saying “look within yourself for the truth”.

(the source/read more: Wikipedia)