The burner from a lamp utilizing burning fluid, or camphene, is distinguished by the presence of tapered wick tubes extending upward at an angle away from the lamp. While sometimes found with only a single wick tube, they are most frequently found with two, and occasionally even with three or four (quite scarce) or six (rare). Burning fluid was very volatile and this design transferred heat away from the fuel (unlike the design of a whale oil burner). These burners most often had caps attached to small chains to extinguish the flame and to prevent evaporation of the fluid when not in use (as seen in the picture). Fluid burners were almost always made of brass and had a threaded base. The wicks were adjusted by picking from the wick tube opening. They do not have holes or slots like whale oil burner tubes.