Misplaced Pages

#509490

70-408: Because of the challenges of building on a shoal, including laying an underwater crib , it is said to be the "most spectacular engineering achievement" in lighthouse construction on Lake Huron. It took four years to build because weather limited work to mostly the summer season. Workers lived in a structure at the site; one of the limiting conditions. It ranks high as an engineering achievement among all

140-455: A diffraction limited system, which has an increased depth of field, similar to using a small aperture in photography. This form of correction has many limitations that prevent it from gaining popularity in everyday use. Pinhole glasses can be made in a DIY fashion by making small holes in a piece of card which is then held in front of the eyes with a strap or cardboard arms. Glasses may also house other corrective or assistive devices. After

210-519: A steamer to convey the materials to the site. The foundation was laid in a cofferdam protected by a crib made from 12-inch-thick (0.30 m) timber and submerged 11 feet (3.4 m) below the surface. The crib was constructed upon slipways at the depot, like building a ship , then launched and towed by tugboats to the reef, where it was sunk and grounded on the site. This crib is massive: 8,464 square feet (786.3 m) and 24 feet (7.3 m) high (203,136 cubic feet (5,752.2 m)). It created

280-458: A bridge over the nose and hinged arms, known as temples or temple pieces, that rest over the ears. Glasses are typically used for vision correction , such as with reading glasses and glasses used for nearsightedness ; however, without the specialized lenses, they are sometimes used for cosmetic purposes. Safety glasses provide eye protection against flying debris for construction workers or lab technicians; these glasses may have protection on

350-410: A circular lens called a lens blank. Lens blanks are cut to fit the shape of the frame that will hold them. Frame styles vary and fashion trends change over time, resulting in a multitude of lens shapes. For lower power lenses, there are few restrictions, allowing for many trendy and fashionable shapes. Higher power lenses can distort peripheral vision and may become thick and heavy if a large lens shape

420-544: A dozen new lights in that decade. In the 1870s alone, it built 43 new lights on the lakes. During the 1880s, more than 100 lights were constructed. As the new century began, the Lighthouse Board operated 334 major lights, 67 fog horns and 563 buoys on the Great Lakes. During the 19th century, design of Great Lakes lights slowly evolved. Until 1870 the most common design was to build a keeper's dwelling with

490-524: A forty-year period—between 1870 and 1910—when engineers began to build lights on isolated islands, reefs, and shoals that were significant navigational hazards. To that time, light ships such as the Huron were the only practical way to mark the hazards. They were dangerous for the sailors who crewed them and difficult to maintain. "Worse, regardless of the type of anchors used, lightships could be blown off their expected location in severe storms, making them

560-529: A full-sized welding helmet is inconvenient or uncomfortable. These are often called "flash goggles" because they provide protection from welding flash. Nylon frames are usually used for protective eyewear for sports because of their lightweight and flexible properties. Unlike most regular glasses, safety glasses often include protection beside the eyes as well as in front of the eyes. Sunglasses provide more comfort and protection against bright light and often against ultraviolet (UV) light. To properly protect

630-797: A potential liability in the worst weather when captains would depend on the charted location of these lights to measure their own ship's distance from dangerous rocks." Using underwater crib designs, the Board built the Waugoshance Light (1851) on a shoal, and demonstrated a "new level of expertise" in constructing of the Spectacle Reef Light (1874), Stannard Rock Light (1882), and Detroit River Light (1885). "The long and expensive process of building lights" in remote and difficult sites "ended in nationally publicized engineering projects that constructed" Rock of Ages Light (1908) and

700-436: A protected pond, making a base for the cofferdam, a wharf , and worker's quarters. The cofferdam was pumped out to expose the bedrock , upon which the masonry courses were laid. The light's 20-month construction process had to be spread out over a calendar period of four years (1870–1874). No work was possible during the winter, most of the spring, and most of the fall, because of the inclement weather. Bois Blanc Island

770-480: A recent ophthalmic prescription are required. People who need glasses to see often have corrective lens restrictions on their driver's licenses that require them to wear their glasses every time they drive or risk fines or jail time. Some militaries issue prescription glasses to servicemen and women. These are typically GI glasses . Many state prisons in the United States issue glasses to inmates, often in

SECTION 10

#1732798014510

840-432: A separate set of glasses for focusing on close by objects. Reading glasses are available without prescription from drugstores , and offer a cheap, practical solution, though these have a pair of simple lenses of equal power, and so will not correct refraction problems like astigmatism or refractive or prismatic variations between the left and right eye. For the total correction of the individual's sight, glasses complying to

910-650: A wide range of fashions are available, using plastic, metal, wire, and other materials for frames. Glasses can be marked or found by their primary function, but also appear in combinations such as prescription sunglasses or safety glasses with enhanced magnification. Corrective lenses are used to correct refractive errors by bending the light entering the eye in order to alleviate the effects of conditions such as nearsightedness (myopia) , farsightedness (hypermetropia) or astigmatism . The ability of one's eyes to accommodate their focus to near and distant focus alters over time. A common condition in people over forty years old

980-404: Is presbyopia , which is caused by the eye's crystalline lens losing elasticity, progressively reducing the ability of the lens to accommodate (i.e. to focus on objects close to the eye). Few people have a pair of eyes that show exactly equal refractive characteristics; one eye may need a "stronger" (i.e. more refracting) lens than the other. Corrective lenses bring the image back into focus on

1050-455: Is "single vision", which has a uniform refractive index . For people with presbyopia and hyperopia , bifocal and trifocal glasses provide two or three different refractive indices, respectively, and progressive lenses have a continuous gradient. Lenses can also be manufactured with high refractive indices, which allow them to be more lightweight and thinner than their counterparts with "low" refractive indices. Reading glasses provide

1120-413: Is also known to have written on the magnifying properties of lenses. The development of the first eyeglasses took place in northern Italy in the second half of the 13th century. Independently of the development of optical lenses, some cultures developed " sunglasses " for eye protection, without any corrective properties. For example, flat panes of smoky quartz were used in 12th-century China , and

1190-517: Is filtered so that each eye receives a slightly different image. The filters only work for the type of signal they were designed for. Anaglyph 3D glasses have a different colored filter for each eye, typically red and blue or red and green. A polarized 3D system on the other hand uses polarized filters. Polarized 3D glasses allow for color 3D, while the red-blue lenses produce an image with distorted coloration. An active shutter 3D system uses electronic shutters . Head-mounted displays can filter

1260-439: Is no measurable UV light from computer monitors. The problem of computer vision syndrome (CVS) can result from focusing the eyes on a screen for long, continuous periods. Many times the glasses do not appear to have much of a tint, or, if any, a slight yellow tint, but they may be more heavily tinted. Long hours of computer use (not blue light) may cause eye strain. Many eye symptoms caused by computer use will lessen after

1330-404: Is not yet twenty years since there was found the art of making eyeglasses, which make for good vision ... And it is so short a time that this new art, never before extant, was discovered. ... I saw the one who first discovered and practiced it, and I talked to him." Giordano's colleague Friar Alessandro della Spina of Pisa (d. 1313) was soon making eyeglasses. The Ancient Chronicle of

1400-415: Is the nearest point of land, 10 miles (16 km) to 12 miles (19 km) to the northwest; but neither it nor Ninemile Point, 10.3 miles (16.6 km) to the south, formed a suitable staging area for construction. This took place entirely on site. After the construction of workers' quarters on the pier, a fourth-order Fresnel lens was temporarily installed on the roof of one of the buildings. Construction

1470-404: Is used. However, if the lens is too small, it can drastically reduce the field of view. Bifocal , trifocal , and progressive lenses generally require a taller lens shape to leave room for the different segments while preserving an adequate field of view through each segment. Frames with rounded edges are the most efficient for correcting myopic prescriptions, with perfectly round frames being

SECTION 20

#1732798014510

1540-454: The College of Optometrists (UK) is that "the best scientific evidence currently available does not support the use of blue-blocking spectacle lenses in the general population to improve visual performance, alleviate the symptoms of eye fatigue or visual discomfort, improve sleep quality or conserve macula health." The ophthalmic frame is the part of a pair of glasses that is designed to hold

1610-485: The Detroit River Light . The Spectacle Reef Light is an example of this type of structure. This lighthouse -related article is a stub . You can help Misplaced Pages by expanding it . Eyeglasses Glasses , also known as eyeglasses and spectacles , are vision eyewear with clear or tinted lenses mounted in a frame that holds them in front of a person's eyes , typically utilizing

1680-635: The Inuit have used snow goggles for eye protection. The earliest recorded comment on the use of lenses for optical purposes was made in 1268 by Roger Bacon . The first eyeglasses were estimated to have been made in Central Italy , most likely in Pisa or Florence , by about 1290: In a sermon delivered on 23 February 1306, the Dominican friar Giordano da Pisa ( c.  1255 –1311) wrote "It

1750-773: The National Register of Historic Places as site #05000744, defined as "Located in northern Lake Huron, 10.3 miles (16.6 km). NNE of Ninemile Point, Benton Township, Michigan ". Spectacle Reef Lighthouse was one of five lighthouses chosen for the "Lighthouses of the Great Lakes" series; the postage stamp was designed by Howard Koslow in 1995. One lighthouse was chosen on each of the Great Lakes for this series. The five lighthouses are Split Rock Light on Lake Superior , St Joseph Light on Lake Michigan , Spectacle Reef Light on Lake Huron, Marblehead Light (Ohio) on Lake Erie and Thirty Mile Point Light on Lake Ontario . In 2020, The Spectacle Reef Preservation Society

1820-551: The White Shoal (1910) lights. In the early 20th century, the Lighthouse Board and the new Lighthouse Service continued to build new lights on the Great Lakes. For 1925, the Board administered around the Great Lakes: 433 major lights; ten lightships; 129 fog signals; and about 1,000 buoys. Of these 1,771 navigational aids, only 160 stations had resident keepers . By that time, most navigational aids were automated. Most of

1890-457: The "night mode" of different operating systems, which can usually be activated outside of nighttime hours. The American Academy of Ophthalmology (AAO) does not recommend special eyewear for computer use, although it recommends using prescription glasses measured specifically for computer screen distance (depending on individuals, but possibly 20–26 inches from the face), which are not the same as "blue-light blocking" glasses. The position of

1960-585: The 12th century, coinciding with the development of " reading stones ". There are claims that single lens magnifying glasses were being used in China during the Northern Song dynasty (960–1127). Robert Grosseteste 's treatise De iride ( On the Rainbow ), written between 1220 and 1235, mentions using optics to "read the smallest letters at incredible distances". A few years later in 1262, Roger Bacon

2030-526: The 1930s to assist people bedbound by chronic illness or spinal injury, recumbent glasses have more recently been marketed not simply as an assistive device but also as 'lazy glasses'. They do not assist with vision, although they can be worn over regular corrective glasses. Yellow-tinted glasses are a type of glasses with a minor yellow tint. They perform a slight color correction, on top of reducing eyestrain from lack of blinking. They may also be considered minor corrective non-prescription glasses. Depending on

2100-460: The 21st century's Great Lakes lighthouses (excepting e.g. , Poe Reef Light and Gravelly Shoal Light ) had been constructed by 1925. Building on shoals was part of a larger pattern of building 14 reef lights around Michigan, also intended to help ships navigate through and around the shoals and hazards around the Straits of Mackinac. The site was first marked by a buoy in 1868. The construction

2170-536: The Coast Guard notes: "The focal plane is 4 feet 3 inches (1.30 m) above the top of the parapet , making it 97 feet 3 inches (29.64 m) above the top of the submerged rock and 86 feet 3 inches (26.29 m) above the surface of the water. For 34 feet (10 m) up the tower is solid and from them on up it is hollow. In it are five rooms, one above the other each 14 feet (4.3 m) in diameter, with varying heights. The walls of

Spectacle Reef Light - Misplaced Pages Continue

2240-593: The Dominican Monastery of St. Catherine in Pisa records: "Eyeglasses, having first been made by someone else, who was unwilling to share them, he [Spina] made them and shared them with everyone with a cheerful and willing heart." Venice quickly became an important center of manufacture, especially due to using the high-quality glass made at Murano . By 1301, there were guild regulations in Venice governing

2310-874: The Lighthouse Board used the design and a similar process in constructing the Stannard Rock Light in Lake Superior in 1878. The Board achieved economies by getting 'double duty' from the "costly apparatus and machinery purchased" for the Spectacle Reef project. The location of the lighthouse makes it susceptible to wave fetch , which for this reef is 170 miles (270 km) to the southeast. Lake Huron ice fields, known as drift ice , which in this lake can be as much as two or more feet thick and measure thousands of acres in size, are moved by wintertime currents. Masses of these dimensions create "an almost irresistible force", which for Spectacle Reef Light

2380-408: The basic fixed frame with another pair of lenses (optional), that are connected by four-bar linkage . For example, sun lenses could be easily lifted up and down while mixed with myopia lenses that always stay on. Presbyopia lenses could be also combined and easily removed from the field of view if needed without taking off glasses. These glasses are often used for drivers going through tunnels, with

2450-517: The cardinal Hugh de Saint-Cher reading in a scriptorium . Another early example would be a depiction of eyeglasses found north of the Alps in an altarpiece of the church of Bad Wildungen , Germany, in 1403. These early glasses had convex lenses that could correct both hyperopia (farsightedness), and the presbyopia that commonly develops as a symptom of aging . Although concave lenses for myopia (near-sightedness) had made their first appearance in

2520-764: The company, these computer or gaming glasses can also filter out high energy blue and ultra-violet light from LCD screens , fluorescent lighting , and other sources of light. This allows for reduced eye-strain. These glasses can be ordered as standard or prescription lenses that fit into standard optical frames. By the end of the 2010s, eyeglasses that filter out blue light from computers , smartphones and tablets are becoming increasingly popular in response to concerns about problems caused by blue light overexposure. The problems claimed range from dry eyes to eye strain , sleep cycle disruption, up to macular degeneration which can cause partial blindness. They may also block out ultraviolet (UV) radiation. However, there

2590-434: The corrective glass and improve aesthetic appearance (mini telescopic spectacles). They may take the form of self-contained glasses that resemble goggles or binoculars , or may be attached to existing glasses. Recumbent or prism glasses are glasses that use a prism with a 90° refraction to allow the wearer to read or view a screen while lying on their back. Developed by Liverpudlian ophthalmologist Andrew McKie Reid in

2660-466: The development of the transistor in the 1940s, combined eyeglass-hearing aids became popular. With thick-rimmed glasses the fashion at the time, a hearing aid could be concealed in the temple part of the frame. These fell out of fashion after the 1970s, but there are still occasions when combined eyeglass-hearing aids may be useful. Safety glasses are worn to protect the eyes in various situations. They are made with break-proof plastic lenses to protect

2730-615: The eye from flying debris or other matter. Construction workers, factory workers, machinists and lab technicians are often required to wear safety glasses to shield the eyes from flying debris or hazardous splatters such as blood or chemicals. As of 2017, dentists and surgeons in Canada and other countries are required to wear safety glasses to protect against infection from patients' blood or other body fluids. There are also safety glasses for welding , which are styled like wraparound sunglasses, but with much darker lenses, for use in welding where

2800-455: The eyes from the dangers of UV light, sunglasses should have UV-400 blocker to provide good coverage against the entire light spectrum that poses a danger. Light polarization is an added feature that can be applied to sunglass lenses. Polarization filters are positioned to remove horizontally polarized rays of light, which eliminates glare from horizontal surfaces (allowing wearers to see into water when reflected light would otherwise overwhelm

2870-568: The floorboards at Kloster Wienhausen , a convent near Celle in Germany; they have been dated to circa 1400. The world's first specialist shop for spectacles—what we might regard today as an optician —opened in Strasbourg (then Holy Roman Empire , now France) in 1466. The 17th-century claim by Francesco Redi that Salvino degli Armati of Florence invented eyeglasses in the 13th century has been exposed as erroneous. Marco Polo

Spectacle Reef Light - Misplaced Pages Continue

2940-414: The form of clear plastic aviators. Adjustable-focus eyeglasses might be used to replace bifocals or trifocals, or might be used to produce cheaper single-vision glasses (since they do not have to be custom-manufactured for every person). Pinhole glasses are a type of corrective glasses that do not use a lens. Pinhole glasses do not actually refract the light or change focal length. Instead, they create

3010-399: The hollow portion are 5 feet 6 inches (1.68 m) at the bottom, tapering to 16 inches (410 mm) at the spring of the cornice ." Just below the cornice, the blocks of stone are 2 feet (0.61 m) thick. They are interlocked in each course, and fastened together with wrought iron bolts 2 + 1 ⁄ 2 inches (64 mm) thick and 2 feet (0.61 m) long. Likewise,

3080-463: The lenses in the proper position. Ophthalmic frames come in a variety of styles, sizes, materials, shapes, and colors. Various metals and alloys may be used to make glasses, such as gold, silver, aluminum, beryllium , stainless steel , titanium , Monel , and nickel titanium . Natural materials such as wood, bone, ivory, leather and semi-precious or precious stones may also be used. Corrective lenses can be produced in many different shapes from

3150-495: The lenses; however, special prescription sunglasses can be made. People with conditions that have photophobia as a primary symptom (like certain migraine disorders) often wear sunglasses or precision tinted glasses, even indoors and at night. Specialized glasses may be used for viewing specific visual information, for example, 3D glasses for 3D films ( stereoscopy ). Sometimes glasses are worn purely for fashion or aesthetic purposes. Even with glasses used for vision correction,

3220-473: The light more tolerable. Sunglasses may also have corrective lenses, which requires a prescription. Clip-on sunglasses or sunglass clips can be attached to another pair of glasses. Some wrap-around sunglasses are large enough to be worn over another pair of glasses. Otherwise, many people opt to wear contact lenses to correct their vision so that standard sunglasses can be used. The double frame uplifting glasses have one moving frame with one pair of lenses and

3290-402: The light on the dwelling's roof or on a relatively small square tower attached to the house. In the 1870s, so as to raise lights to a higher focal plane , conical brick towers, usually between 80 and 100 feet tall, were constructed. In the 1890s steel-lined towers began to replace the older generation of brick buildings, such as Big Sable Point Light . The Spectacle Reef Light was built during

3360-420: The lighthouse, which had to be repaired at very great expense. The term "gale" is being used loosely, as there was no wind speed device being monitored in the winter at that location. But in a similar location and storm on Lake Superior at Granite Island, Michigan , wind speeds of 143 miles per hour (230 km/h) were recorded on January 18, 2003. "After the winter of 1873–74, when the keepers returned to

3430-705: The lighthouses built on the Great lakes. In 2020, The Spectacle Reef Preservation Society was formed and began to restore the lighthouse. From 1852 to the beginning of the 20th century, the United States Lighthouse Board was active in building lighthouses to support ship traffic on the Great Lakes . Between 1852 and 1860, it built 26 new lights. Even as the American Civil War and its aftermath slowed construction, it completed

3500-517: The loss and breaking of the glasses. Sunglasses allow for better vision in bright daylight and are used to protect one's eyes against damage from excessive levels of ultraviolet light . Typical sunglasses lenses are tinted for protection against bright light or polarized to remove glare; photochromic glasses are clear or lightly tinted in dark or indoor conditions, but turn into sunglasses when they come into contact with ultraviolet light. Most over-the-counter sunglasses do not have corrective power in

3570-406: The mid-15th century, it was not until 1604 that Johannes Kepler published the first correct explanation as to why convex and concave lenses could correct presbyopia and myopia. Early frames for glasses consisted of two magnifying glasses riveted together by the handles so that they could grip the nose. These are referred to as "rivet spectacles". The earliest surviving examples were found under

SECTION 50

#1732798014510

3640-534: The most efficient. Before the advent of eyeglasses as a fashion item, when frames were constructed with only functionality in mind, virtually all eyeglasses were either round , oval , panto, rectangular , octagonal , or square . It was not until glasses began to be seen as an accessory that different shapes were introduced to be more aesthetically pleasing than functional. Scattered evidence exists for use of visual aid devices in Greek and Roman times, most prominently

3710-657: The newly completed tower, they found the ice piled against it at a height of 30 feet (9.1 m), or 7 feet (2.1 m) higher than the doorway, and they could not gain entrance until they had cut away the iceberg of which the lighthouse formed the core." The Lighthouse Board built a model of this light that was featured in the Aids to Navigation display at the 1893 World's Columbian Exposition , also known as "The Chicago World's Fair " in Chicago , Illinois . The original second-order Fresnel lens (by Henry–Lepaute of Paris, France)

3780-399: The potential of future shipwrecks. The lighthouse is built upon a reef shaped like a pair of eyeglasses (hence its name) and is located in the path of littoral commerce on Lake Huron. The increase in freighter traffic through the straits increased the risk of more ship losses without better signing of hazards. The Spectacle Reef Lighthouse cost $ 406,000. One costly item was the purchase of

3850-460: The retina. They are made to conform to the prescription of an ophthalmologist or optometrist . A lensmeter can be used to verify the specifications of an existing pair of glasses. Corrective eyeglasses can significantly improve the life quality of the wearer. Not only do they enhance the wearer's visual experience, but can also reduce problems that result from eye strain, such as headaches or squinting. The most common type of corrective lens

3920-423: The sale of eyeglasses and a separate guild of Venetian spectacle makers was formed in 1320. In the fourteenth century, they were very common objects: Francesco Petrarca says in one of his letters that, until he was 60, he did not need glasses, and Franco Sacchetti mentions them often in his Trecentonovelle . The earliest pictorial evidence for the use of eyeglasses is Tommaso da Modena 's 1352 portrait of

3990-639: The scene). Polarized sunglasses may present some difficulties for pilots since reflections from water and other structures often used to gauge altitude may be removed. Liquid-crystal displays emit polarized light, making them sometimes difficult to view with polarized sunglasses. Sunglasses may be worn for aesthetic purposes, or simply to hide the eyes. Examples of sunglasses that were popular for these reasons include tea shades and mirrorshades . Many blind people wear nearly opaque glasses to hide their eyes for cosmetic reasons. Many people with light sensitivity conditions wear sunglasses or other tinted glasses to make

4060-430: The sides of the eyes as well as in the lenses. Some types of safety glasses are used to protect against visible and near-visible light or radiation . Glasses are worn for eye protection in some sports, such as squash . Glasses wearers may use a strap to prevent the glasses from falling off. Wearers of glasses that are used only part of the time may have the glasses attached to a cord that goes around their neck to prevent

4130-681: The signal electronically and then transmit light directly into the viewer's eyes. Anaglyph and polarized glasses are distributed to audiences at 3D movies . Polarized and active shutter glasses are used with many home theaters. Head-mounted displays are used by a single person, but the input signal can be shared between multiple units. Glasses can also provide magnification that is useful for people with vision impairments or specific occupational demands. An example would be bioptics or bioptic telescopes which have small telescopes mounted on, in, or behind their regular lenses. Newer designs use smaller lightweight telescopes, which can be embedded into

4200-410: The site where they were filled with stone so they sank in place. The crib was then leveled and capped with concrete or masonry on which the lighthouse structure was constructed. Crib lighthouses were built extensively in the Great Lakes region, as the hardrock bottoms of these water bodies provided ideal foundations. Problems arose however if the crib settled unevenly into the earth as was the case with

4270-434: The tower is bolted to the foundation rock with bolts 3 feet (0.91 m) long. After "the stones were in place they were plugged with pure portland cement , which is now as hard as the stone itself. Hence the tower is, in effect, a monolith ." The stones were cut at the depot at Scammon's Harbor, 16 miles (26 km) away. They were fitted, course by course, on a platform of masonry. The stones fit so well that each course

SECTION 60

#1732798014510

4340-423: The upper frame serving as sunglasses and the second frame as transparent lenses. The illusion of three dimensions on a two-dimensional surface can be created by providing each eye with different visual information. 3D glasses create the illusion of three dimensions by filtering a signal containing information for both eyes. The signal, often light reflected off a movie screen or emitted from an electronic display,

4410-430: The usage of the computer is stopped. Decreasing evening screen time and setting devices to night mode will improve sleep. Several studies have shown that blue light from computers does not lead to eye diseases, including macular degeneration. The total amount of light entering the eyes can be adjusted without glasses using the screen brightness settings. Similarly, the blue light can often specifically be adjusted using

4480-657: The use of an emerald by Emperor Nero as mentioned by Pliny the Elder . The use of a convex lens to form an enlarged/magnified image was most likely described in Ptolemy 's Optics (which survives only in a poor Arabic translation). Ptolemy's description of lenses was commented upon and improved by Ibn Sahl (10th century) and most notably by Alhazen ( Book of Optics , c.  1021 ). Latin translations of Ptolemy's Optics and of Alhazen became available in Europe in

4550-400: Was "overcome by interposing a structure against which the ice is crushed and by which its motion is so impeded that it grounds on the 7–foot shoal." This creates an effective wall "against other ice fields." The tower is formed as a " frustum of a cone ". The 32-foot-diameter (9.8 m) base rises 93 feet (28 m) above water level, and is 11 feet (3.4 m) below water level. As

4620-499: Was almost complete in the fall of 1873, when the onset of winter's storms forced the work site to be abandoned until the following spring. In the spring of 1874, work on the lighthouse began again. With the installation of the cast-iron lantern room and a new second-order Fresnel lens, the work was complete, and the light was put into service in June 1874. The combination of a crib foundation with monolithic stone masonry worked so well that

4690-429: Was formed and swiftly began the process of restoring the lighthouse. Crib lighthouse A Crib lighthouse is a type of lighthouse whose structure rests on a concrete or masonry foundation supported with wooden beams. The name "crib" refers to the wooden crib pier style of construction which was used as a foundation for lighthouses. When it came time to build, wooden cribs were constructed onshore then towed to

4760-409: Was laid in three days: to set, drill, and bolt. The light has been described as "the best specimen of monolithic stone masonry in the United States" and "one of the greatest engineering feats on the Great Lakes ." The light has an attached fog signal building, oil house and storage building. There are davits to raise and lower boats. In September 1872, a severe gale did considerable damage to

4830-750: Was removed in 1982. It is now on display at the Inland Seas Maritime Museum (also known as the Great Lakes Historical Society Museum ) at the Vermilion Light in Vermilion, Ohio . Since the Fresnel lens was replaced by a modern acrylic lens, the Spectacle Reef Light has continued to serve as an active aid to navigation as of 2007. In July 2005, "Spectacle Reef Light Station" was listed on

4900-417: Was undertaken under the auspices of the Lighthouse Board and was a feat of civil engineering and endurance. Construction began in 1870, in answer to the disastrous loss of a large number of ships during the 1860s at the site; in particular, two schooners ran aground and broke up in 1867. The massive cost of the loss helped convince Congress that it would be more cost effective to build a light and reduce

#509490