Mercury Ceiling Light

Mercury Ceiling Light is a late-game light source that gradually charges up to full output instead of turning on at a fixed brightness instantly. It uses mercury as fuel and electricity while operating, and its light intensity scales directly with its current charge, making it a controllable, ramping illumination source rather than a simple on/off lamp.

When supplied with enough mercury through pipes and enough power, Mercury Ceiling Light consumes 130 g/s of mercury and 60 W of electricity while increasing its charge by 1/60 per second. At that rate, it reaches full charge in 1 minute. If either mercury or power is insufficient, the charge drops by 1/60 per second until it reaches zero. This means the building can be kept at any intermediate brightness by carefully controlling its fuel input or by pulsing its automation signal, letting players tune light levels instead of relying only on maximum output.

Its lighting behavior is also unusual compared to ordinary point lights. When active, Mercury Ceiling Light emits three parallel beams and creates a 3×8 rectangular lit area. Brightness is strongest within 0-3 tiles, where it can reach 60,000 lux. At 4-6 tiles, the light falls to half strength, with a maximum of 30,000 lux. At 7 tiles, it drops to one third strength, with a maximum of 20,000 lux. Because of this beam pattern, placement matters more than with a standard circular light source, and the lamp is best used where a narrow rectangular wash of light is desirable.

A few practical points follow from its design:

• It is slow to reach full brightness, so it is not ideal for situations that need instant maximum light.
• Once charged, it provides very strong illumination for a compact, rectangular space.
• Automation or throttled mercury supply can be used to hold the lamp at a specific brightness level.
• If the supply of mercury or power is interrupted, brightness steadily decays rather than failing instantly.

Mercury Ceiling Light is therefore most useful in setups that can support a steady fuel line and power draw, especially where controlled brightness and a distinctive beam-shaped lighting pattern are more important than immediate startup.