But the brothers had to face many handicaps and inconveniences. Their whole taking was small compared with the huge area of the adjoining Dowlais ironworks. The latter, being built higher up the same stream which supplied water to both, and being the older-established concern, had the first call and command of its use, a most important factor during dry seasons. The Penydarren works had very little coal, and had to take a lease for coal from the Dowlais Co. In another case, on the same plot of land, the Dowlais Co. worked the coal while the Homfray brothers worked the iron-ore. Constant quarrels ensued which led to fierce and costly lawsuits, in which the Penydarren partners were generally the losers.

After many years of co-operation the two brothers, Jeremiah and Samuel, as managing directors of the Penydarren iron-works, sought new fields of enterprise for their superabundant energy.

Jeremiah Homfray m. (1787) Mary, daughter of John Richards of Llandaff, and for many years resided at Llandaff House. After a few years, he complained of his brother's arbitrary management. This led to a quarrel between the brothers (1796) and to legal action. About the same time Jeremiah quitted the Ebbw Vale iron-works, of which for a few months he was the sole owner, until Messrs. Harford, Partridge & Co. joined him as the more responsible managers, employing him as the salaried superintendent of the works.

We next hear of him at Aber-nant, in the Aberdare Valley. With Birch as a practical engineer, he commenced arranging leases of mineral lands at Aber-nant, Cwm-bach, and Rhigos (1800) which he transferred to the Tappendens. By 1803 he had become a partner in the Hirwaun iron-works, but again soon quitted this field of operations. He ‘was … a great prospector in the South Wales mineral field. He arranged leases of mineral properties, an then sought partners; and after helping to establish the respective iron-works, and set them going, he retired …’ He was entitled to an annuity of £2,500 payable during his life (probably from Penydarren), and £10 from the Aber-nant iron-works. But having a large family, and living in style (especially during the period when he was high sheriff of Glamorgan in 1809-10 — he was also acting high sheriff in 1810-11) and taking up costly leases of coal-mining properties and farms in the neighbourhood of Pontypridd, he soon got into financial difficulties. In 1813, Sir Jeremiah Homfray, then cited as of Cwm Rhondda, coal-merchant, dealer, and chapman, was declared a bankrupt. In Nov. 1813, his dwelling-house at Cwm Rhondda was sold together with its contents. He then left for Boulogne to avoid paying all his creditors and to live on his reduced income, and it was there that his wife (1830) and he (1833) d. and were buried. His son, JOHN HOMFRAY, bought Penllyn castle.

Samuel m. Jane, daughter of Sir Charles Gould Morgan (see Morgan of Tredegar family), 1st bart., of Tredegar Park, and this enabled him to obtain a lease of mineral land of about 3,000 acres upon very cheap terms at Tredegar, in conjunction with Richard Fother-gill (q.v.) and Matthew Monkhouse (1800). Here again, as his brother did at Ebbw Vale, he was able to work off some of his superabundant energy by establishing the Tredegar iron-works with such success that during 1809 the Monmouthshire canal carried 9,105 tons of iron from their works, a quantity greater than that of any of the other dozen or so of the Monmouthshire iron-works except that of Blaenavon. In 1806 he issued an address as a candidate for a seat in Parliament for Brecknock, but withdrew before the election day. He became high sheriff of Monmouthshire in 1813 and, in June 1818, M.P. for the borough of Stafford. He d. 22 May 1822 in London and was buried at Bassaleg. His eldest son, SAMUEL GEORGE HOMFRAY (b. 7 Dec. 1795, d. 16 Nov. 1882) was high sheriff of Monmouthshire in 1841 and alderman of Newport (and mayor 1854-5).