Perhaps you should try some spelling variations:
early tomography » early typography, early photography, ray tomography
delay telegraph » solar telegraph, delay tomography, aerial telegraph
der telegraph » der telegraphen, der telegraphie, _ telegraph

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((early tomography) OR (((delay telegraph) OR (der telegraph)))).
• Adding a wildcard symbol may retrieve word variants: ((early tomography) or (((delay telegraph) or (der telegraph))))*.