There is another mode of catching Pilchards of "_Driving Nets_,"[72] which are drawn after their respective boats, fastened only at one end; in the meshes of which the fish are arrested as they attempt to pass. This species of fishery is always carried on at a considerable distance from the shore, lest, by approaching too near the land they should disperse the shoals which the _Seiner_ is waiting to enclose. The quantity thus taken is very small; but the fish are remarkably fine, and the expense of the adventure is comparatively trifling. The fish, having been brought to the fish cellars, undergo the process of being "_cured_;" which is performed by laying them up in broad piles, "_in bulk_," as it is called, and salting them as they are piled up, with bay salt. In this situation they generally remain for forty days, although the time allowed for their lying _in bulk_ is often regulated by the interests of the merchant, who, it may be supposed, is ever ready to avail himself of any favourable turn in the foreign markets. The period directed by Government is that of thirty-three days. During this process a great quantity of oil, blood, and dirty pickle, drains from the fish; and which, from the inclination of the floor, immediately find their way into a receptacle placed for their reception.[73] The Pilchards, when taken from the bulk, are carried to large troughs, in which they are washed, and completely cleansed from the salt, filth, and coagulated oil which they had acquired.[74] They are then packed into hogsheads, and pressed by a strong lever, for the purpose of squeezing out the oil, which issues through a hole at the bottom of the cask; the pressing continues for a week, and formerly ten gallons of oil were procured from every hogshead, but at this time, not more than four can be obtained; such a change in the fatness of the fish is not easily to be explained. The hogsheads are now _headed up_, and exported to the different ports of the Mediterranean, principally to the Italian ports; and upon every hogshead so exported, Government allows a bounty of 8s 6d. Upwards of 30,000 hogsheads are annually consumed in England; and above 100,000 have been exported in one year. The quantity of salt necessary to cure a hogshead of fish is estimated at about 300 lbs. and the expense of the whole for that quantity, including the cask, salt, labour, &c. is from £1:3s to £1:6s; and it has been calculated that the bounty, together with the value of the oil (from £20 to £28 per ton), will in general reimburse the whole expense. This fishery is in every respect of the highest importance to the county of Cornwall, affording employment to at least twelve thousand persons,[75] whilst the capital engaged cannot be fairly estimated at less than three hundred and fifty, or four hundred thousand pounds.