The silver seems to have been cast into plates or ingots varying from ten to twenty pounds in weight and value (for the monetary pound was simply the pound weight of standard silver). Its purity probably varied, for while in 1296 the pound of refined silver was mixed with 14d. of alloy to bring it to the standard,[175] a few years later silver weighing £132, 5s. was worth only £131, 13s. 7¼d. in coined money,[176] and 370 lbs. of silver sent up from Martinstowe in 1294 had to be further refined in London before it could be made into silver vessels for the Countess of Barre.[177] In the case of the lead we have the usual medieval complexity of weights. An early entry[178] records that 'a carretate (or cartload) of lead of the Peak contains 24 fotinels, each of 70 lbs., and the fotinel contains 14 cuts[179] of 5 lbs. A carretate of London is larger by 420 lbs.' The London weight appears to have gained the day, as a later entry gives 13½ lbs. to a stone, 6 stones to a foot, and 30 feet (or 2430 lbs.) to a carretate 'according to the weight of the Peak.'[180] In Devon we find in 1297 carretates of 24 feet and 32 feet in use simultaneously, the foot being 70 lbs. here as in Derbyshire.[181]
In no other part of England had the lead-mining industry so continuous a history of steady prosperity as in Derbyshire. The Devon mines seem to have been richer and more productive during a short period, but the half century, 1290-1340 practically covers the period of their boom. During the five years, 1292-1297, these mines produced £4046 of silver, and about £360 worth of lead; next year the silver amounted to £1450. Then in April 1299 the king leased the mines to the Friscobaldi, Italian merchants and money-lenders, with whom he had many dealings.[182] They agreed to pay 13s. 4d. a load for the ore, but after about a year, during which time they drew some 3600 loads of ore,[183] they found that they were losing heavily, the ore not being worth more than 10s. a load, and the costs of working being higher than they had expected.[184] The mines, however, continued to yield well when worked by the king for his own benefit, as much as £1773 of silver and £180 from lead being obtained in 1305: this, however, seems to have been the highwater mark, the yield for 1347 being only £70.[185] After this the mines were let to private adventurers from time to time; but such records as we have do not suggest that many fortunes were made from them: in 1426 the yield for the previous two and a half years had been 39 ounces of silver,[186] for the year 1442 it was £17,[187] but for the six years, 1445-51, the average output rose to 4000 ounces.[188] At the beginning of the boom, in 1295, it was found necessary to recruit labour from the older lead-mining districts, and commissioners were appointed to select miners for Devon from Cheshire, Earl Warenne's liberty of Bromfield in Shropshire, the Peak, Gloucester, Somerset, and Dorset.[189] The ordinances of 1297 stipulated for 150 miners from the Peak, and an equal number of local men from Devon and Cornwall, though the accounts show that there were that year 384 miners from the Peak, and 35 from Wales.[190] On the other hand, in 1296, while we have over 300 miners coming from the Peak, a twelve days' journey, we also find four picked men sent from Devon to the king's court, and thence to Ireland to prospect on the king's behalf.[191]
The prosperity of the Devon mines caused an increase of activity in those of Somerset, where a number of fresh strikes were reported during the early years of the fourteenth century, about one of which an optimistic lead reeve wrote to the Bishop of Bath and Wells as follows:[192]—
'Know, my lord, that your workmen have found a splendid mine[193] of lead on the Mendips to the east of Priddy, and one that can be opened up with no trouble, being only five or six feet below the ground. And since these workmen are so often thieves, craftily separating the silver from the lead, stealthily taking it away, and when they have collected a quantity fleeing like thieves and deserting their work, as has frequently happened in times past, therefore your bailiffs are causing the ore to be carried to your court of Wookey where there is a furnace built at which the workmen smelt the ore under supervision of certain persons appointed by your steward. And as the steward, bailiffs, and workmen consider that there is a great deal of silver in the lead, on account of its whiteness and sonority, they beg that you will send them as soon as possible a good and faithful workman upon whom they can rely. I have seen the first piece of lead smelted there, of great size and weight, which when it is struck rings almost like silver, wherefore I agree with the others that if it is faithfully worked the business should prove of immense value to yourself and to the neighbourhood, and if a reliable workman is obtained I think that it would be expedient to smelt the ore where it is dug, on account of the labour of carrying so heavy material such a distance. The ore is in grains like sand.'
There is no evidence that this mine fulfilled the sanguine expectations of its discoverers, but about the same time, in 1314, we find Herman de Alemannia and other adventurers working a mine in Brushford, near Dulverton.[194] The Germans were for many centuries the most skilled miners, and English mining owes much to their enterprise. As an instance of their greater skill we may take the case of Thomas de Alemaigne, silver finer,[195] who being out of work petitioned the king to grant him the refuse and slag (les aftirwas et les remisailles) thrown aside at the mines in Devonshire, which had been refined so far as those at the mines could refine them: no one else would touch them, so the king would get no gain unless he granted them to Thomas, who was willing to pay 20s. a year for the right to rework them. This same Thomas de Alemaigne was appointed in 1324 to dig, cleanse, and examine the king's mines in Cumberland and Westmoreland.[196] Probably these mines had not been worked for some time previous, as in 1292 the total issues of the Alston mines for the last fourteen years were said to have been £4, 0s. 2d., possibly owing to the absence of fuel, which is given as the reason for an iron mine there being worth only 15s. a year.[197] Later, in 1359, Tilman de Cologne was farming the Alston mines, and in 1475, as a result apparently of a report by George Willarby[198] that there were in the north of England three notable mines, one containing 27 lbs. of silver to the fodder of lead with a vein half a rod broad, another 18 lbs. with a vein five rods broad, and the third 4 lbs. with a vein 1¼ rods broad, the mines of Blaunchlond in Northumberland, Fletchers in Alston, Keswick in Cumberland, and also the copper mine near Richmond, were granted for fifteen years to the Duke of Gloucester, the Earl of Northumberland, William Goderswyk, and John Marchall.[199] The two noblemen were presumably sleeping partners, and appear to have abandoned the arrangement, as soon afterwards, in 1478, William Goderswyk, Henry Van Orel, Arnold van Anne, and Albert Millyng of Cologne, and Dederic van Riswyk of England, received a grant for ten years of all mines of gold, silver, copper, and lead in Northumberland, Cumberland, and Westmoreland, paying one-fifteenth of the profits.[200]
Although gold is mentioned in this last entry and in a number of other grants of mines in the fifteenth century, and though Galias de Lune and his partners were licensed in 1462 to dig ores containing gold in Gloucestershire and Somerset,[201] gold does not appear to have been worked in paying quantities in England. In 1325 John de Wylwringword was sent down to the mines of Devon and Cornwall to seek for gold: he obtained from the Devon mines 22 dwt., of which he refined 3 dwt. at Exeter; this yielded 2½ dwt. of pure gold.[202] The remainder was sent up to the Exchequer and eventually refined at York; but this is almost the only note we have of gold being found, though no doubt small quantities were found from time to time in the Cornish stream tinworks.
In 1545 one St. Clere declared that certain gold called 'gold hoppes and gold oore' in every stream tinwork in Devon and Cornwall was by ignorance of the tinners molten with the tin, and so conveyed abroad; certain persons were appointed to test his statement.[203]