"a small room adjoining the Lodge, in which, preparatory to initiation, the candidate is enclosed for the purpose of indulging in those serious meditations which its sombre appearance and the gloomy emblems with which it is furnished are calculated to produce. It is also used in some of the advanced degrees for a similar purpose.
This small room or chamber, which does not necessarily adjoins the Lodge room, is dark, with the walls painted black, or, as in one case I saw, imitating a rocky underground cave. It contains the following: a simple rough wooden table on which we find: a human skull, usually on two crossbones, a chunk of bread, a pitcher with water, a cup with salt, a cup with sulphur, a lighted candle or lantern, an hourglass, paper, ink and pen, a wooden stool or chair painted on the wall: a rooster, a sickle, the acronym V.IT.R.I.O.L.(U.M.) and various sayings."
Candle flame is that what illuminates, dispels darkness
Cross bones represent Death
The hour glass represents time
Bread represents manna
Water (the living mercury) Sulfur and salt are the ingredients to produce the stone
Sickle also represents death and Saturn, lead or the rough substance to be worked
In other words, time is slipping, death is near, there is work still to be completed!
The cock announces the break of a new day
Original masons would have understood this but yes they have become lazy