County Of Cornwall Research Articles

XI. On a native arseniate of lead

I. That the oxide of lead and the arsenic acid, might be found in the state of natural combination, is a supposition highly probable, from the strong affinity which subsists between these two substances. But the existence of such a compound has not, as I conceive, hitherto been established by such proofs, as entitle it to be ranked amongst the decided cases of mineralogical science. I trust, therefore, that the observations, which I have the honour of submitting to the Society, on a new ore of lead lately discovered in the county of Cornwall, so justly celebrated as well for the variety as for the richness of its mineral productions, will not be deemed superfluous. This mineral was raised in the mine called Huel-Unity, a very rich copper mine, in the parish of Gwennap. According to the information with which I have been favoured by Mr. William Davey, a very intelligent and experienced miner in that district, it was found in a lode south of Huel-Unity prin­cipal lode, at the depth of fifty fathoms below the surface, which lode underlay about two feet in the fathom south: at the depth abovementioned; this lode fell in, or formed a junc­tion with another small lode or vein to the south, and when the junction took place, this lead ore was found. The veins of it are, in general, from six to ten inches wide, and they diverge on going west. Some particles of this lead ore have been found in the southern part, after the separation of the lodes; but the northern lode does not contain any, until the junction takes place. This ore is intermixed with some native copper, very rich gray copper, and black copper ore, and some is mixed with quartz. The walls of both veins are killas.

XXIII. Experiments on a mineral substance formerly supposed to be zeolite; with some remarks on two species of uran-glimmer

This mineral is raised in a mine called Stenna Gwyn, in the parish of St. Stephenʼs, in Branwell, in the county of Cornwall; the principal production of which is the compound sulphuret of tin, copper, and iron.

X. Description of the arseniates of copper, and of iron, from the county of Cornwall

The natural combination of the arsenic acid with copper, and the different aspects under which this combination appears, according to the proportions in which these two substances are united, were among those objects of mineralogy, respecting which our imperfect knowledge required the aid of study and observation. A new copper mine, lately worked, called Huel Gorland, in the parish of Gwennap, in the county of Cornwall, having, within the last two years, enriched the cabinets of London with some very fine specimens of these arseniates, I have been induced to pay particular attention to them; and I offer the result of my observations to the Royal Society, as an acknowledgment of that gratitude which I and all Frenchmen, faithful to their king, ought to feel and profess to a country which has distinguished itself as the protector of honour and loyalty. Although there appears, according to some German authors, reason to think that arseniate of copper has been found in Silesia, its much greater abundance, as well as the various aspects under which it exists, in the county of Cornwall, may entitle it to be considered as one of the many mineral substances which are peculiar, or nearly so, to England.

XVI. Account of Antiquities discovered in Cornwall, 1774. By Philip Rashleigh, Esq. F.A.S.

In the year 1774, as some tinners were searching for tin in a stream-work near St. Austell, in the county of Cornwall, about 17 feet under the surface of the ground, they discovered a silver cup, which is now used for wine at the Communion Table, in which were several antient pieces of ornament, for a person of high rank, as represented in Pl. VIII. The cup was placed in a heap of loose stones, the refuse of an old tin-work, and covered with a common slate, where it was probably hid in troublesome times, either by the owner, or by some person who stole it. The quantity of earth and stone which had accumulated over the cup since it was deposited in the stream-work, shews that it had remained there for a great number of years. The cup was very thin and brittle, and fell into so many pieces as to prevent its being united. Besides the articles represented in the drawing, it contained many of the most curious Saxon coins ever discovered at one time. These with the other pieces of antiquity fell out in moving the ground, and some were probably lost in Shovelling about the rubbish. Those which were picked up were in a few hours disperst about the country, and many of them broken. The greatest part were afterwards collected; and are at Menabilly in Cornwall.

XIV. An account of the effects of a storm of thunder and lightning, in the parishes of Looe and Lanreath, in the county of Cornwall, on the 27th Day of June, 1756. Communicated to the Rev. Jeremiah Milles, D. D. F. R. S. in two letters, one from the Rev. Mr. Dyer, Minister of Looe, and the other from the

On Sunday the 27th of June last it grew on a sudden as dark as a winter evening: soon after, the lightning began to flash, and the thunder to roar.