The gas plant installed at the Chestnut Street Theatre by Dr. Charles Kugler in 1816 was unusual. It employed dissolved pitch, rather than soft coal, as the source for the illuminating gas it produced.* In all other respects, however, it was typical of small gas plants of the period. Parts 1, 2 and 3 are where the gas was actually produced. The fire-box (3) heated a sealed chamber (2) filled with blocks of pitch. Turpentine (1) dripped into the chamber to dissolve the pitch. The advantage of pitch over soft coal, commonly used in England and later in North America, was that pitch contained little hydrogen sulphide and was therefore largely odor free. From the retort (2) the raw gas passed through a pipe (4) to the gasometer, the storage and pressurizing chamber. This pipe entered the gasometer, which was filled with a chemical bath (6) to remove tars and odor-causing chemicals, below the water line, and was topped with a cap (5), similar to an inverted drinking glass, from under which the gas could escape but which kept water out of the pipe. Once free of the water bath, the gas was collected under a counter-weighted hood (11). The counter-weights could be adjusted to allow the gasometer to fill with gas (i.e., by allowing the hood to "float" upward), then readjusted to force the gas -- under pressure -- out the supply pipe (8) to the theatre building.
William Warren's Journal for July 11, 1816, indicated he "saw Archy McCall [who often did carpentry and haulage for the theatre] abt lighting the Theatre with Gas." On the 22nd of that month he tells us "I am making arrangements with Dr. Kugler to light the theatre next season [i.e., the fall season of 1816] with Gas." Warren spent the fall of 1816 in Baltimore with the Chestnut Street Theatre company, returning to Philadelphia on the evening of Saturday, November 23rd, two days before the opening of the winter season, to see "the theatre lighted with gas." It was, he observed in his diary, "very fine.