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Lacquering :
Various lacquers are used to give metal or wood a protective or decorative covering. They are applied hot or cold, by brush, spray or by dipping. Shellac dissolved in methylated spirit, or cellulose solution, or other lacquers, are used for brass parts such as clock plates, cases, dials, etc. Clear lacquers are suitable on silver to protect it from tarnish. Lacquering on wood is a specialized decorative treatment.

Lancet Clock :
A type of longcase or bracket clock with a case shaped at the top in the form of a pointed Gothic arch. This design is encountered during the early 19th century in England and continued into the reign of Queen Victoria. It is typical of other domestic furnishing of the late Gothic Revival and often included the decoration of the mahogany or rosewood veneered case with inlaid classical ornament and stringing in brass.

Lantern Clock :
So called because of its frame's resemblance to a lantern. Other names have been used, including Cromwellian and bedpost clock, the former because the bell at the top suggested a Cromwellian helmet and the latter because of the four turned columns at each corner of the frame. The lantern clock was developed in England with similar versions in other countries, during the 17th century, and superceded the wrought-iron wall clock. Originally it was designed to hang from a hook on the wall and early specimens still retain their iron hook rings and distance spurs. The spurs were fitted into the rear pendant 'feet' to permit the clock to hang vertically and to alow space for the pendulum, which was adapted to lantern clocks by Ahasuerus Fromanteel I just before 1660. Previously, a large wrought-iron balance was the only form of escapement employed, and it was notoriously inaccurate. Verge escapements with short bob pendulums were used for lantern-clock movements until well into the 18th century, but with the introduction of the long 'royal' pendulum with a one-second beat, many conversions were carried out. About the time of these conversions lantern clocks were often arranged to stand on wooden wall brackets. With only a few exceptions, the lantern clock was fitted with one hand, but sometimes there was also an alarm mechanism.

Lantern Clock, Japanese :
Lantern clocks were the first type produced by the Japanese to imitate European clocks. Other styles of clocks were developed, but the lantern remained the standard for large clocks until 1873. The Japanese usually substituted two ropes and weights, one for each train, for the single rope and weight for both trains commonly found on contemporary European lantern clocks. Notched, weighted foliots or balance wheels with verge escapements were the common method of governing the rate. Seasonal adjustments for varying hour lengths were made by moving the weights on the notched foliots (single or double), or, on balance-wheel clocks, by moving the adjustable hour indicators. Single and double window calendars appear in the 18th century, and late clocks have turned corner pillars. The construction of Japanese houses usually prevented lantern clocks from being hung on the walls, so they were frequently placed in a wood and glass hood on top of a pyramidal or table stand which enclosed the weights. Some lantern clocks, usually small ones, were put into wall bracket cases suspended from a support column.

Lathe :
A machine in which metal, wood or other material is mounted horizontally, rotated, and cut or turned. Material to be revolved in a lathe is mounted either between the centers of the lathe or fixed to the headstock spindle. A lathe can be a small simple tool or a large complicated machine. An ordinary 'clockmaker's' or engineering lathe is seldom made for any special purpose, but when suitably equipped with accessories its versatility is such that an endless variety of work can be machined on it. It can be converted into a drilling, milling, dividing or planing machine. The basic part of a lathe is the bed on which the headstock, which contains the rotating spindle, the tailstock, which has a detachable center, and the toolrest, which supports the cutting tool, are mounted. The headstock spindle and the tailstock runner or barrel can be solid or hollow, and can also be provided with a loose center, face plate, collet or chuck. The toolrest in its simple form supports the cutting tool for hand work, but a compound slide rest has a top slide on which the cutting tool is secured, and permits the tool to be moved axially along the work in the lathe. The top slide is mounted on a cross-slide which moves across the lathe axis, both slides being operated by screws. A compound slide is often fitted to a carriage which moves along the bed of the lathe by means of a rack and pinion, or by gearing to the headstock spindle. The latter is incorporated for the automatic feeding or screw-cutting. A top slide can often be swivelled to an angle relative to the lathe axis for taper turning.

Lathe, Automatic :
A lathe specially designed and set up for the purpose of mass-producing specific parts by automatically performing several machining operations in succession, such as turning, threading, milling, counterboring and parting off. With some automatic lathes it is possible to feed the material in long lengths, which will be made into many parts without further attention from the operator. Sometimes blanks on a conveyor are fed into the lathe at great speed, and some automatic machines have a number of rotating spindles and cutting tools which are horizontally or vertically mounted.

Lathe, Capstan :
A type of lathe fitted with accessories set up for rapid production of identical parts. The distinguishing feature is the self-indexing capstan or tool head which holds several previously positioned tools that perform in succession various cutting operations, such as turning, drilling, counterboring and threading. The capstan is mounted on a slide, the base of which is clamped to the lathe bed at a convenient distance from the headstock. Movement of the slide carries the capstan to the work, the reverse movement removing the slide and indexing the capstan by rotating it with the next tool in position before it is again brought back to the work. It is usual to have a cut-off slide fitted to a capstan lathe for parting-off work produced from a rod. To permit more rod to be quickly brought ready for cutting, a quick-change collet chuck is fitted to the lathe spindle.

Leading-off Work :
Early turret clocks seldom had dials, and indicated the passage of time by striking the hours on a bell. when dials were fitted, the hands were connected to the clock by rods; the gears and rods to the dial (or dials) are known as leading-off work. In the 18th century the leading-off work was fitted with a friction clutch and a setting dial. These features made it possible to set the clock to time without having to 'pump' the escapement or stop it.

Leaves :
The teeth of the pinion gears.

Lifting Piece :
The two-armed lever used in striking clocks to release the striking work.

Light Clock :
In 1960 Patek Philippe, a Geneva-based firm, marketed a clock to rival the Atmos clock for perpetuance of motion. Housed in a variety of case styles, the clock has a transparent panel on the top of the case which allows light to fall upon a photocell, this generating electrical power when the light intensity is sufficiently high. A delicate electric motor transforms this power into mechanical motion, which is used to wind up the mainspring of a conventional mechanical movement fitted with a lever escapement, the clock being of the highest quality. Four hours of illumination with natural or artificial light is sufficient to give 24 hours of spring reserve of going, and higher levels of illumination give a more rapid rate of winding. When fully wound, the mainspring can power the clock for three days without further exposure to light.

Lighthouse Clock :
A unique clock made by Simon Willard in 1822, featuring an octagonal base, a mahogany case, a tapered circular trunk, and a glass dome covering an eight-day alarm movement.

Line, Gut :
The strong thin cord used to hang a clock weight or to connect the mainspring to the fusee in lower-quality fusee clocks, good fusee clocks having chains. The best gut clock lines were made from sheep's intestines, but monofilament nylon is now used as a safer alternative.

Line, Rope :
Rope is often used to drive early lantern-frame clocks and has a special open weave which is not easily damaged by the spiked pulley. Clock rope is still available in various thicknesses.

Line, Wire :
Clocks with a longer going time than eight days require heavy weights or strong springs to drive them, and stranded steel-wire lines are often used. Steel lines, however, disfigure the barrel and fusee and should only be used on clocks requiring them.

Local Time :
The time of day at any particular place, found by astronomical instruments. The difference in local time between one place and another is proportional to the difference in longitude, 15 degrees of longitude being equivalent to one hour of time.

Log, Mechanical :
A device for measuring the distance covered by a ship at sea. It consists essentially of a propeller or fan-driven rotor suspended from a float towed behind a ship, combined with a mechanism for recording the number of its revolutions, from which the distance travelled can be calculated.

Long-case Clock :
The original name for a grandfather clock. This domestic clock first appeared in England shortly after the Restoration of 1660, about the same time as longcases appeared in Europe. At first it was less than 7 ft. high, with ebonized case, architectural hood, gilded ormolu mounts and a narrow trunk. Early brass dials were about 9 in. square; later, the case was made wider to accommodate the long 'royal' pendulum which superceded the short bob pendulum, c.1675. Cases then became taller and wider until the appearance of the elephantine cases of provincial clocks of the early 19th century. All longcase clocks had brass dials until the introduction of the painted dial, c. 1770. Casework, in keeping with other furniture fashions, made use of marquetry and walnut veneer until the introduction of mahogany, c. 1735. Satinwood was used in the Adam period and rosewood during the Regency, though oak was retained for the cheaper type of clock throughout the era.

Long-case Clock, Dutch (Staande Klok) :
Amsterdam was the most important center for the making of longcase clocks in Holland, principally because it had become an important commercial center by the second quarter of the 18th century. The first longcase clocks made in the Netherlands, c. 1680, were probably in imitation of English examples. The older types of Dutch longcase clock have square dials, while their plinths are flat on all surfaces. After 1720 arch dials were introduced, and slightly later the plinth was bowed on the sides and front. During the second quarter of the 18th century the longcase clock reached the peak of its development, with finely made cases and sometimes astronomical work and other refinements, such as musical work providing from six to as many as 24 tunes. The waning prosperity of the country in the second half of the 18th century and increased competition from much cheaper French pendulum clocks led to the gradual disappearance of the Dutch longcase, at least from the larger towns in the west of the country. Even the making of longcase clocks in the French style did nothing to halt this process. In the first half of the 19th century, however, longcase clocks were still being made in rural centers.

Long-case Clock, Italian :
Between the 17th and 19th centuries in Italy, as in other countries, domestic clocks were made to be placed either on brackets or shelves, or to stand on the floor. Many craftsmen made clocks of the latter kind, with movements much like those of English lantern clocks but generally in much simpler cases. the finest examples were made in Emilio and Bologna during the 18th century, with Carlo Maria Fiorini, Binaldo Gandolfi, and Guiseppe and Filippo Bellei in Modena, the most prominent makers. Although the clocks were more functional than decorative, they were noticeable for their elegance of form. Fine brass dials, generally with delicate engraving, brass feet and mouldings, finely made movements and sometimes an almost eccentric brilliance in the solution of problems of striking, were all characteristic. Movements usually consisted of two main horizontal plates of iron, four pillars in iron or brass at the corners and vertical brass strips to support the trains. In the upper part were one or more bells, with generally a decorative moulding on the upper one.

Looking-Glass Clock :
A clock with a box-like case and mirror instead of a painted-glass tablet.

Lunar Cycle :
A cycle of 19 years after which the phases of the moon recur on very nearly the same days of the year; also known as the 'Metonic cycle', from its discoverer, in 432 BC, the Athenian astronomer Meton. The number of any given year in its current cycle is known as 'the Golden Number'.

Lunar Motion Work :
The mechanism driving the lunar dial or hand of a clock.

Lyre Clock :
A form of banjo clock with a lyre shape, generally made of mahogany. It frequently has acanthus leaves coarsely carved on the center panel, a base piece below the framed or panelled door and ornamental figure or finial on top. Some cases were entirely gilded and some had solid wood panels rather than painted or gilded glasses. On rare occasions both lyre and banjo wall clocks were made as strikers, with two weights running within the center portion.