Thomas and T. Powell

Rouen, Engineers.
Successor in some way to Hall, Powell and Scott
Founded by Thomas Powell (1802-1864), who took his son Thomas Powell (Son) into the business. His nephew, Thomas Powell (Nephew), also joined the business at some point.
1852 Constructed an engine for the spinning mill of M. Lavoisier at Darnetal, near Rouen, which the firm improved in 1869 by renewing the cylinders, jacket, and valve gear and running comparative tests.
1866 Thomas Powell (Nephew) modified a Woolf engine to improve expansion in the small cylinder.[1]
1879 Exhibited a compound beam engine with Correy's expansion gear at the Paris Exhibition. Mr. Powell had recently published a paper on the Correy gear which was read at the Institution of Mechanical Engineers in Paris[2] (see Engineering 21 June 1878 p504, which seems to have been presented by Thomas Powell (Son) since he makes specific reference to Thomas Powell (Nephew), and Engineering 12 July 1878 p36).
Presumably predecessor of Thomas Powell, Rouen