Iron forge at Caerleon
On 25 June I continued my trip in the afternoon in the company of two Quakers, Mr Roberts and Mr Williams, to Caerleon, which means a town for a Roman legion. It is located eight miles from the Severn on a navigable river. Mr Roberts has recently built a forge with three hearths, a little way from the town. We went to see it, and it is shown in drawing no. 153.

The frame of the hammer was built of brick. The breast-shot wheels for the bellows and hammer and their buckets were designed according to Spanish or Biscayan practice. Nevertheless, the head of water here is high enough to permit the use of over-shot wheels, but they would not be more advantageous in this case when the wheels run at high speed, because it is more difficult for the water to escape from the deep buckets that one must employ on over-shot wheels, than to leave the shallow and open buckets on a breast-shot wheel.

The three hearths were divided in such a way that two were used for the melting of the iron and called finery hearths, while the third, on the other hand, was only used for forging the bars and called a chafery hearth.

The finery hearths are made of cast-iron slabs, 2 feet long, 15 inches wide and 6 inches to 6½ inches deep below the tuyere, which was forged of wrought-iron.

The chafery is larger across, so that it is possible to place in it, side by side, four lumps of iron as they come from the finery hearths, drawn out in the middle to a length of 1 foot, 6 inches or 2 feet as shown in the attached drawing no. 154a [sic.] [see footnote b]. Across the end of the chafery hearth there is an upright slab of iron, which serves to keep the coal together and heaped up high [Fig. 154b] [sic.].

This gives a more intense heat. Both kinds of hearths use nothing but charcoal, which mostly is made in this locality from oak, lime, beech, etc. Sometimes birch and other deciduous trees are mixed in. Charcoal is very expensive here, because in the neighbourhood, for several miles around, there are no other trees than those planted in the hedges surrounding the fields and meadows.

Calculation of the price of the iron

One load of coal here costs 36 shillings. A load consists of 12 horse loads and each horse load is a sack, which should fill a coal-measure 3 feet square and 20 inches deep [see footnote d].

In the refinery the workers are allowed 18 horse loads, or one-and-a-half loads of coal per ton of iron. At the chafery, 12 sacks or one load of coal is allowed per ton of iron. The total consumption of coal is thus two-and-a-half loads, or £5.8s.0d. [see footnote e]. Three men work at each refinery hearth, or six altogether, paid 10s 6d per ton. Two refinery hearths can produce 6 tons of iron per week and the same 6 tons can be forged to bars in the chafery, if only there is sufficient water. At this forge water is sometimes scarce, particularly when the weather is very dry. The pig iron used at this forge is made at Abercarn, which lies further away from the sea, 18 English or three Swedish miles from Caerleon. It is brought here on horseback and the transport costs 8 shillings per ton. The pig iron is in the form of slabs 2 feet, 3 inches to 2 feet, 6 inches long and 6 inches wide at the middle. They are nowadays reckoned to cost £6 per ton at the furnace. 26½cwt of pig iron or one-and-three-quarters tons [see footnote f] is allowed per ton of bar-iron, but the finers told me that they do not need quite so much when the pig iron is of good quality. For each bloom or loop, three-quarters of a hundredweight or 84 lb of pig iron is used and 20 loops are made per 24 hours.

Footnotes

Please note, the footnotes have been renumbered for convenience.

[b] The 'lumps of iron' shown are clearly in the form of what are known as 'anconies', the products of forging a bloom in the finery. The ends are usually of rough square section, finished to the final shape of the bar in the chafery.
[c] This calculation must be regarded as approximate as RRA allows one-third wastage, and in fact 3 x £14.13s.4d = £44, so an extra 13s.4d has crept in.
[d] Presumably 'load' means a wagon load. A measure of the dimensions given would have a volume of 15 cubic feet or 11.7 bushels.
[e] Again, an error has crept in: 2.5 x 36s = £4.10s.
[f] In fact, one-and-a-third tons.