Complex sentence: Haslam ran the foundry by himself from 6 February 1873 when his father retired from the partnership, and it became the Haslam Foundry and Engineering Company Ltd in 1876.
Split into simpler sentences: Haslam ran the foundry by himself from 6 February 1873 when his father retired from the partnership. This foundry became the Haslam Foundry and Engineering Company Ltd in 1876.