Filling room: This was where the gunpowder charges would be made up. The gunpowder barrels were emptied into a large lead lined oak bin. Copper scoops were then used to measure out the different size of charges. The amount of gunpowder needed for each charge was about a third of the weight of the shot. For a 12 pounder gun, firing a 12lb (5.45kg) round shot, approximately 4lbs (1.81kg) of gunpowder was used. Once the charges were made up they were stored in 3 different areas on the ship so that they were not mixed up. The charges for the 32 pounder guns were stored in the racks on either side of the filling room. The charges for the 24 and 12 pounders were stored in the 2 hanging magazines that are accessed from the orlop deck.
Light Room: For obvious reasons no naked flames were allowed near the gunpowder. This meant that the palleting flat and filling room were illuminated from the separate light room. Two lanthorns (lanterns) were housed in light boxes at the front of the light room and heavy sheets of glass separated the light room from the filling room. To prevent the glass from being accidentally broken a copper wire mesh covered the glass giving it greater strength. For added safety the light room had a separate entrance from the other two areas of the grand magazine and was accessed via a ladder at the back of the light room. During a battle the ship's master-at-arms and the cook manned the light room.