 Complete the following phrase:  Dredge was employed from 1858 to 1861 as an engineer in the office of Daniel Kinnear Clark. In 1862, he was employed by John Fowler, and worked on the District Railway in London. In January 1866, he ventured into engineering journalism, joining the weekly journal Engineering. In the late 1860s, he mainly illustrated for the journal, writing the occasional article, attending the great 