Jeffreys Parry De Winton was a marine engineer who came to Caernarfon as a guest of the squire of Glynllifon. The squire persuaded Owen Thomas, a native of Caernarfon and the owner of a very successful foundry on St. Helen’s Road to go into partnership with him in 1854 and the company became known as Thomas & De Winton.
The business flourished and in 1866 Owen Thomas died and De Winton took on his son, also called Owen Thomas as a Junior partner, but from then on the company was called merely De Winton & Co. The company was well known as a supplier of boilers to some of the best known ships of the day that came to Caernarfon to be fitted with new parts, the largest of which was a screw steamer the “Livadia”.
Jeffreys Parry De Winton was Mayor of Caernarfon in 1870 - 1872, he left the town in 1890 and died in 1892. Work at the foundry came to an end in 1901/02