For Converting Intervals of Sidereal Time into Equivalent Intervals of Mean Solar Time.

HOURS.

MINUTES.

SECONDS.

FRACTIONS OF A
SECOND.

ut

mean time.

BLOCKS, TACKLES, AND ROPE.
VARIOUS KINDS, PRACTICAL RULES, ETC.

WIRE-RIGGING, CUTTING AND FITTING.

CABLES. DATA CONCERNING CHAIN CABLES,

WIRE CABLES.

ANCHORS. RULES FOR WEIGHTS AND DIMENSIONS.

SAILS, CANVAS, ETC., REMARKS ON.

PAINTING SHIP.

MIXING COLORS, VARNISHES, ETC. STAINING AND DYEING.

MISCELLANEOUS RECIPES.

TIMBER PRESERVATION AND SEASONING.

INTERNAL ECONOMY.

SCRAPING SPARS, CLEANING DECKS, REPLACING
COPPER, DRESSING SHIP, ANCHORING IN
FOREIGN PORTS, STOWING PROVISIONS,
ETC., ETC.

EXTEMPORARY MEASUREMENTS.

BLOCKS.

BLOCKS are mechanical contrivances, possessing the properties of pulleys. A block consists of the shell, sheave, pin and strap. The shell is the frame or outside part, and is usually made of ash. In the made block it consists of two or more pieces pinned together, the outside pieces being called the cheeks. In the morticed block the shell is composed of but one piece of wood, morticed out to receive the sheave.

On the sides and at each end of the shell of a block, a single or double score is cut to allow the strap to fit snugly on the block.

The sheive is the roller over which the rope runs, and is made of metal or lignum-vitæ. It has a hole in the centre to receive the pin, which may be of iron or copper, hardened.

In a lignum-vitæ sheave, the pin-hole is usually bouched, or lined with composition to protect the sheave from chafe. In what are known as patent blocks the sheave contains friction rollers, and these are now generally used in cases where the blocks are not subject to great strain.

The strap is the rope or band around the shell, by which it is attached to its particular place.

The swallow is the aperture through which the rope reeves. The hook is attached to the strap, and is prevented from chafing by means of a thimble. The breech is the end of the block farthest from the

hook.

Blocks are single, double, treble, or fourfold, according to the number of sheaves contained within the shell. The size of a block is determined by the length of the shell. The sizes in general use in the Navy range from 4 inches to 24 inches inclusive.

Under the general name of blocks may be included hearts, deadeyes, and bull's-eyes, which receive the ends of stays and shrouds, wooden thimbles, fairleaders, euphroes for awnings, cleats, cavils, wooden rollers, chocks, toggles, travellers, wooden-hanks, hoops, trucks,

etc.

Blocks take their names from some peculiarity of form; from the position they occupy; or from the purpose to which they are applied.

Bee-blocks, or bees, are pieces of oak bolted to the bowsprit, for the fore-topmast and spring stays to reeve through.

Cat-block is a large block, usually treble, used to raise the anchor to the cathead.

Cheek-blocks are half shells which bolt against a mast or spar, which forms the other half shell. Used on gaffs for brails, etc.

Clump-blocks are short and thick, as the tack and sheet blocks. Clew-garnet-blocks are single blocks banging under the quarters of the lower yards, and receive the clew-garnets by which the courses are hauled up. The same name is applied to the blocks which hook in the clews of those sails.

Clew-line-blocks are attached to the clews of the topsails for the

clew-lines.

Dasher-block is a block at the end of the spanker gaff for reeving the ensign halliards.

Euphroe is a long piece of wood, having a number of holes in it, through which the crow-foot for the awning is rove.

Fiddle-block has a long shell, with one sheave over the other. Used for yard tackles and top burtons.

Fly-block is the upper block of the topsail halliards.

Gin-blocks are large composition sheaves which turn in a metal framework.

Girtline-blocks are single blocks used to reeve single whips called girtlines or gantlines.

Hanging-blocks are used at the mastheads for the halliards of the jibs and staysails. They usually have friction rollers.

Jack-blocks are single blocks, sometimes used for sending up and down light yards.

Jeer-blocks are large treble or fourfold blocks for reeving the purchases for sending up and down lower yards.

Jewel-blocks are single blocks at the ends of the yards, used to reeve studding-sail halliards.

Main sheet-block is a double or treble block, strapped or hooked to the main-boom of a schooner or sloop, for the main-sheet.

Quarter-blocks on the topsail and topgallant yards, are double