S18

HISTORY OF ENGINEERING.

Rook I.

The platform is of Memel timber ; the joints arc caulked down upon the girders, and arecovered with 3-inch plank.

The front of the pier is protected by dolphins, one in the centre, and one outside eachwing, and the whole of the piles are sheathed with copper. The dolphins keep the bargeat a parallel distance from the T head, where the platform is approached by two flights ofstairs, with landings at convenient levels between the outer rows of columns, and a trans-verse flight from above.

'Hie roof of the pier is of iron ; the principals are formed of two pieces of wrought angleiron, with a wood flitch between them, to which the slate boards are nailed ; they aretrussed with wrought-iron, with a cast-iron strut on either side. The supporting bracketsarc secured to the gutters by two wrought iron bolts, which are carried through the gutter.Six small skylights are placed over the platform at the entrance, to admit light when theshutters at the side are closed.

The lighthouse over the T head is supported upon four inclined truss bearers; the centreof the lantern is 40 feet above the datum level of high water ; and the total height from thebase of the outer foundations to the summit of the vane is 82 feet.

The pier, lighted by gas, was opened to the public two years after its commencement, inApril, 1843. Messrs. Fox, Henderson, and Co. were the contractors.

Chatham has a dockyard and arsenal on the banks of the Medway, which were establishedabout the reign of Queen Elizabeth; and Camden describes it as “ stored for the finest fleetthe sun ever beheld, and ready at a minute’s warning.” James I. formed the ordnancewharf, on the site of the old dock ; since which time capacious wet docks, slips, masthouses, rope walks, sail lofts, smiths’ shops, and other buildings, have been erectedupon a very extensive scale, and some of the largest ships in the navy have been con-structed there. Near the town of Rochester is a victualling office, composed of severalextensive ranges of building, appropriated to the use of the shipping at Chatham, Sheer-ness , and the Nore.

Sheemess is another dockyard on the Medway, near where that river unites with theThames ; it is the chief town of the Isle of Shoppy, and situated at its extreme southernpoint. This yard w*as chiefly established for the repair of vessels that were but partiallydamaged; but during the last fifty years vast sums of money have been expended upon itto render the docks complete, and fitted for other uses.

Fig.323.

8HEERNESS.

It is well supplied with spring water from a well sunk in 1781,328 feet in depth. Whenthe workmen had penetrated through the chalk, and were trying the strata with an auger,it suddenly dropped, and the water gushed up with such velocity, that the men could withdifficulty be drawn out ; in six hours the water rose 190 feet, and in a few days was within8 feet of the top, and though constantly in use, it has never been lowered more than