Time-intensity plots of Si, Fe, Ti II, Cu, and Li lines using 0.25-inch cupped electrodes containing different proportions of sample and admixtures.____._-_____-____-___-___-34. Time-intensity plots of Si, Fe, Ti II, Cu, and Li lines using deep-bore electrode No. 2 (bore depth 0.75 inch) containing different proportions of sample and admixtures._________ 35. Gas jet for 0.25-inch-diameter cupped electrode. A, Photograph showing electrode; B, diagram showing jet parts in exploded view._______._._._.____.____.__.__..._____-_ 241 36. Photograph of gas jet for 0.125-inch-diameter deep-bore constant-feed electrode shown in position on arc stand. ______ 37. Diagram of gas jet shown in figure 36 mounted directly on optical bench_______________________________________ 243 38. Spectra obtained from a G-1:LUB4Of. graphite mixture arced in atmospheres of COg, Ar-Og, and He-Og gases using deepbore electrodes-______________________________________ 244 39. Water-cooled gas jet used with deep-bore constant-feed electrode No. 3. A, Photograph showing ceramic cup of figure 36 replaced by brass collar; B, diagrams of top and side views. 246 40. Time-intensity plots of several elements using a gas-cooled and water-cooled jet with deep-bore constant-feed electrode No. 3._____________.