Further~ From http://twsitelines.info/SMR/1017
Quote"Wilhelm Bertram, a steelmaker from Remscheid in Germany, was shipwrecked off the north Durham coast in 1693.
A few years later he was said to be in charge of a furnace in Newcastle. By 1720 Bertram had transferred to Blackhall Mill, acting as steelmaker for the furnace owned by Hayford. The Hollow Sword Blade Company,
which was originally set up near Shotley Bridge in about 1686 by German immigrants, was apparently being supplied with cementation steel by Hayford
. There is a description of the works in H. Kalmeter "Dagbok ofver en 1718-1726 Foretagen Resa", vol 1, folios 349-350. There is a picture of the furnace in R.R. Angerstein
, 1753, "Resa genom England, 1753-1755". Bertram pioneered the production of German steel by forging blister steel. Angerstein says that the "Shear Steel" mark - a stamp showing crossed shear blades, was Bertram's own mark
. Indded the making of "Shear Steel" was introduced into Sheffield by a workman from Blackhall Mill in 1767. Bertram died around 1740. In 1753 his son was running Blackhall Mill
. At this time some 30 tons of "German steel" was made in a year with a further 100 tons or so of blister steel in simple bars. The steel from Newcastle and Blackhall Mill was said to be the best in England, due to the care taken in selecting the iron, and its processing. The furnaces had chests 127 inches long, made from sandstone. The flues and vaults were of Stourbridge bricks and the rest of the structure was in dressed stone. The furnace chimneys were 28-30 feet high with a top diameter of about 3 feet. In 1810 and 1811 the Blackhall Mill site was being worked by the Cooksons. It is omitted from a list of steel manufacturers for 1863 (see Spencer 1864), so must have gone out of operation some time between 1811 and 1863. It may have closed at the same time as Cookson's works in Newcastle, which were abandoned in 1851-53. A postcard dated 1913 shows Blackhall Mill essentially similar to the nearby Derwencote furnace, without the buttresses. Blackhall Mill was demolished in 1916 to make way for a school house."Unquote.