V. View of interior much the same as in II. The secondary and various coils placed inside, particularly the central “extra coil”, are resonating. The latter is connected to a point of the first secondary turn about 3/4 turns from ground connection, nevertheless the streamers are powerful. Other coils are connected to the same point while a ball 30" on a stand and a coil on a stand are connected to the last turn of secondary. Strong sparks were passing from top to bottom of extra coil and the secondary last turn shows strong streamers. About 100 short flashes or throws of switch and afterwards an exposure of 15 minutes to ordinary arc lamp placed in corner of building for the purpose of photography. The arc light is much preferable to flash light as the time can be closely determined in each case. The isochromatic plate is decidedly better. In this plate there is a red dye used in coloring the plate, otherwise it is the same as the Cramer “Crown”. The plate used was “instantaneous Cramer isochromatic”, same size as those before. This observation suggests a line of experiment which might lead to useful results. It would consist in using plates each dyed with a different color to bring out specific effects. The vibrations of the system was the normal or nearly so as recorded in previous notes.
