Daylighting of narrow basement areas under pavements in Georgian England began with open iron grills above an external area usually in front of a basement window which threw light into the interior of the basement room.
 
Coal holes in the pavement or road to allow coal to be stored in basement cellars were also covered by open wrought iron grills or plates with holes in, usually fixed by chains to prevent burglars, again to allow light into the coal cellar.
 
Glazed pavement lights started out as fixed thick sheets of glass, easily broken on impact, which were gradually reduced in size and increased in thickness, ultimately using protective wood, iron or stone ridges which protruded slightly above the level of the glass to provide some impact protection.
 
In 1845, Thaddeus Hyatt (1816-1901), a New York inventor, patented a circular iron 'illuminated vault cover' inset with small blocks of pyramidical prism glass and even smaller ventilation holes. Hyatt moved to England and brought his invention with him (eventually dying on the Isle of Wight).
 
Hyatt's 1845 patent mentions the older glazed pavement lights:
The covers for vaults which have been fitted with glass, have, as heretofore constructed, consisted, in general, of a metal rim, which was made to contain a large plano-convex glass. These glasses are extremely liable to fracture, and when broken leave large and dangerous openings within their rims; and from their thickness, and their soon becoming scratched over their whole external surface, the quantity of light admitted by them is much less than would seem to be due to their size. To obviate these objections, I have so contrived my illuminating vault-cover, as to admit the light through a considerable number of small glasses, or lenses, which are so set into the iron cover, as actually to defend them from injury by the falling or pressure of weighty bodies upon them, or from the expansion and contraction of the metal, they being protected by knobs, or protuberances on the iron cover, and defended also by being set in a frame work of wood or of soft metal, or of wood and soft metal combined, which will yield to percussion and thus aid effectively in preventing the breaking of the glass. combine a ventilator with my vault cover, in such a manner as to allow a current of air, or vapor, to pass freely, while the entrance of water from without, under ordinary circumstances, is prevented.
 
Hyatt moved to London and his warehouse in Farringdon Road was next door to Christopher Dresser's. Hyatt's pavement lights can be seen in USA and UK cities.
 
Pavement lights were preferred to open grills, especially in commercial buildings and shops which abutted pavements and a number of legal test cases tried to bring clarity to pavement ownership, and whether or what kind of permission was required, and who was responsible for accidents caused by them. Some pavement lights were tiled with geometric border tiles between the glass cells.
 
By the 1870s the ubiquitous large wrought or cast iron rectangular pavement lights began to be seen throughout cities where rainfall was frequent and shopping mandatory. Iron companies vied over the precise nature of their prism lights and which cast the best light from pavement level down and inwards towards the room below. Eventually concrete took over from iron, with the prismatic glass cells
 
Names of pavement light inventors and makers:
Thaddeus Hyatt - Louisville, New York, London - 1845, 1855, circular, hexagonal, rectangular iron and glass
Burt & Potts - circular coal hole iron and round glass - Westminster
St Pancras Ironwork Co - Basement Lighting Engineers- octagonal glass and iron - London
Manufacturer - St Pancras Iron Work Co London. Henry Bessemer first produced steel here.
Improved Pavement Light Co - Marlborough - rectangular cast iron and glass - London
J A King Co - rectangular iron and glass - London
John McGuigan Co - Simplex - 1912 - San Francisco
Lely's Semi Prism Lights - rectangular cast iron and glass
Hayward Brothers - rectangular, circular, iron and glass - London - produced most of the pavement lights still in existence in London.
Bergers - Raydiant Sidewalk Lights - rectangular concrete and glass - San Francisco
P H Jackson - 1904 patent steel locking frames with reinforced lenses - rectangular concrete and glass - San Francisco
American 3 Way Luxfer Prism, American Luxfer Prism Co - rectangular concrete and glass - Chicago, New York, Boston, Seattle
American Bar Lock - Crushproof Sidewalk Light - rectangular concrete and glass - Long Island
Phoenix Sidewalk Light - rectangular concrete and glass - San Francisco
 
Note 1: Thaddeus Hyatt was an abolitionist and friend of John Brown, was imprisoned for refusing to testify against him after the raid on Harpers Ferry. The song, John Brown's Body Lies A-mouldering In His Grave, commemorates the raid on the federal armory at Harpers Ferry, Virginia in 1859, which sparked the American civil war. John Brown, who believed that armed insurrection was the answer to slavery was defeated by General Robert E Lee and executed.
 
Note 2: The inevitable repro - you can now buy reproduction iron pavement lights from a company called New Age Glass, but the cells are clear glass and do not seem to be prismatic
 
Link below to the companies currently make vault lights or pavement lights, structural glass blocks and panels, or related ironwork.