The book of the lantern : being a practical guide to the working of the optical (or magic) lantern : with full and precise directions for making and coloring lantern pictures (1889)
Hepworth, Thomas Cradock, -1905 · New York : E.L. Wilson · leaf 102
80 THE BOOK OF THE LANTERN. each lantern alternately has the great merit of saving nearly half the gas bill. It will be noticed in the cut of the dissolving tap that it is furnished with two small stop- … cocks, which are fixed on vertical tubes near its centre. These tubes are by-passes which allow a small quantity of gas to pass to each burner, although the lever has shut off the main supply. The necessity for this arrange- ment is obvious ; without it the lantern not in actual use would be…
Lantern projection
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
![An illustration from [Graphophone patents] (1878)](https://img.insideoutlibrary.com/img/200/ia-graphophonepaten15unit-987-514.webp)
