When Jehl worked for Lowrey he was responsible for making multiple copies of a wide range of documents using Edison's electric pen.

Edison had given Jehl specific instructions to keep him informed daily with the tests and experiments that he conducted and the results obtained.

With the results that Edison received from Jehl, he was able to make informed decisions on how to create things, like the thermal regulator for the meter.

They promulgated the watt-hour meter and parallel circuit distribution grid that Edison had developed with his team including Francis Upton.

This diary was the foundation for Jehl's personal book, titled Reminiscences of Menlo Park, which was published fifty years afterwards.