A HISTORY OF CORNWALL For the purpose of raising the china clay to the surface and preparing it for export, the fol- lowing method is generally adopted, allowance being made for such modifications as the nature of the locality and economical working require. A shaft having been sunk to the required depth alongside the deposit, a level is then driven under- neath the clay which is to be raised. From the level thus made another shaft or ' rise ' is carried, through the clay, to the surface. The over- burden of earth and foreign matter having been removed, a square wooden pipe or ' launder ' is inserted in the c rise ' which is then filled up with clay. This 'launder' is furnished at intervals with holes which, until occasion requires, are kept closed. Arrangements having been made for the supply of a small but continuous stream of water to the clay bed, the surface of the clay bed is now broken up with picks so as to enable the clay to mix readily with the water. The water, holding the clay in suspension, is then carried down the ' launder ' and along the level to the shaft, whence it is pumped to the surface. The milk-white liquid is next conveyed by a series of channels to the clay pit, the channels being so arranged, and the rate of flow so regulated by hatches, as to ensure the deposition of all the heavier particles of sand and mica on the way. In the clay pit the clay is allowed to settle and the water is drawn off, to be used over again for the same purpose. From the pit the clay is ' landed ' into an adjacent tank by the removal of a plug near the bottom of the pit. While in the tank the surface water is drawn off from time to time until the clay assumes the consis- tency of thick cream. From the tank the clay is conveyed to the kiln, where it is cut up into squares, and the remaining moisture driven off by the application of artificial heat. It is now ready for transit. The uses of china clay are various. It has been stated, on good authority, that probably not more than one-third of the clay now produced is used in the manufacture of porcelain. In the sizing of cotton goods and in paper-making for the purpose of adding weight and consistency ; and in the manufacture of alum, ultramarine, crayons, water colours, and other similar pro- ducts, vast quantities of china clay are required, both at home and abroad. Besides supplying the home markets, the chief of which are the Staf- fordshire Potteries and Lancashire, there is a con- siderable export to the United States, Holland, Belgium, Italy, Spain, France, Germany, and Austria. A good clay-bed will produce from I to 2^ tons of clay to every cubic fathom. The selling price of china clay per ton is from I y. to 25*. ; but the larger amount consists of medium clays. The official estimate of the value of the output for the year 1904 was evidently calcu- lated upon a much lower selling price, for the purpose, doubtless, of including inferior products, mica-clay, etc. Even so, considerably over 320,000 was realized by the merchants in that year, and there are at present no signs of a decline. China Stone is granitic rock consisting of quartz, decomposed felspar, and white mica. It occurs chiefly in the parishes of St. Austell, St. Denys, and St. Stephen in Brannel, and has long been used in these and in the neighbouring parishes for building purposes. The towers of Probus and St. Stephen's churches are built of china stone. In 1817 the amount shipped for the manufacture of pottery exceeded that of china clay ; but of recent years, although the output has steadily increased, it has formed less than one-eighth of the whole. Its price varies, according to the quality of the stone, from 8*. to 12s. per ton. China stone is obtained by quarrying, and before being used, requires to be finely ground. The grinding is sometimes per- formed in Cornwall, but usually it is done at the potteries, where also an addition of felspar and other ingredients is made to meet the require- ments of the particular ware it is sought to manufacture. 1 1 A carefully written and exhaustive account of the ' Hensbarrow Granite District ' by J. H. Collins, F.G.S., appeared in 1878. To this and to the mineral statistics published by the Home Department, and also to Mr. F. N. Olver of St. Just for advice, the present writer is chiefly indebted for the fore- going sketch. Much interesting matter may be found in ' A Treatise on China Clay,' by David Cock. The chapter devoted to this industry by Mr. Brenton Symons, F.C.S., in his ' Geology of Cornwall,' is for the most part a verbatim reprint of the account given by Mr. Collins, to whose work the reader is referred for a fuller treatment of the subject. HORTICULTURE The warm and equable climate rather than steps which have led to its present importance, the nature of the soil of the south-western por- The home of the industry is Tresco, one of the tion of Cornwall and of the isles of Scilly has islands of Scilly, and its parent and prototype, within recent years led to the extensive culti- the narcissus. Various theories have been pro- vation of flowers for the London and other pounded to account for the presence, from time markets. Inasmuch as this particular industry immemorial, of some half-dozen varieties of this has grown up within living memory, it be- flower, chiefly at Holy Vale and at Tresco. comes necessary to indicate briefly the successive Whether these were introduced by some mem- 578
