These three diagrams, drawn by the Cruft Laboratory at Harvard University, relate to a cathode-ray oscillograph. The first two drawings show the arrangement of knobs and dials on the outside of the instrument(s), while the third comprises a series of circuit diagrams.
Printed at the bottom of the second diagram are a list of instrument components.
A cathode ray oscillograph is a particular type of cathode-ray oscilloscope. A cathode-ray oscilloscope visualizes the wave-forms of voltage signals. In a cathode-ray oscillograph, the cathode ray makes a permanent record (photographic or otherwise) of these measurements.
For more information, see this website about the
cathode-ray oscilloscope.