Estefanía Herrero-García, Ignacio-Jaier Gil-Crespo 365 Industrial technology and brick vaults construction in Spain, 18th century: The Royal Glass Factory in La Granja Estefanía Herrero-García 1 and Ignacio-Javier Gil-Crespo 2 1. Ms Architect, Sociedad Española de Historia de la Construcción; 2. PhD Architect, Sociedad Española de Historia de la Construcción Introduction When the new Bourbon dynasty began in Spain at the beginning the 18th century, the craftsmanship and production of materials and elements destined for the Crown were improved and the industry modernised. New factories were built, and the best craftsmen were brought to Spain to design and develop a new production system. For the layout, design and construction of these new factories, several topics were very important such as the choice of a settlement close to the forests (wood as fuel), raw materials and water (machinery motor power), in addition to proximity to roads and the towns where the workers lived. La Real Fábrica de Cristales de La Granja (The Royal Glass Factory in La Granja, Segovia) was built and enlarged along the 18th century. The construction process reveals how the builders made decisions about the distribution of the works for glass manufacturing, considering the position of the kilns, the expulsion of smoke, the lighting, the construction techniques and even places for the workers relaxation. Brick vaults were erected to avoid fires, and several of them were built without centering. Two large domes function as chimneys. There were 32 sets to temper the glass, and the surplus heat was used to warm the rooms for the workers. The position and orientation of the glass polishing tables were very important because this machinery needed the force of water for moving material and the glass had to be near windows oriented towards West, to facilitate the detection of defects and irregularities. The wooden warehouses were placed closer to the kilns. The authors have drafted the Master Plan of this building and have studied its history, its construction, its operations, its relationship with other similar factories in Spain and Europe, as well as other issues such as cultural heritage, management, conservation, maintenance, and architectural proposals [1]. This piece will examine both the technical requirements and the construction process of this building. Pre-industrial modernization in Spain (18th century) and the establishment of the Royal Glass Factory in La Granja The change of dynasty in the Crown of Spain, with the advent of Bourbons, meant the rise of the Enlightenment ideas, the adoption of the French mercantilism and the introduction of an economical production process. The inspiration for setting up new state-sponsored industries was born in the Manufactures et fabriques du
Industrial technology and brick vaults construction in Spain, 18th century: The Royal Glass Factory in La Granja
Estefanía Herrero-García1 and Ignacio-Javier Gil-Crespo2 1. Ms Architect, Sociedad Española de Historia de la Construcción; 2. PhD Architect, Sociedad Española de Historia de la Construcción
Introduction
When the new Bourbon dynasty began in Spain at the beginning the 18th century, the craftsmanship and production of materials and elements destined for the Crown were improved and the industry modernised. New factories were built, and the best craftsmen were brought to Spain to design and develop a new production system. For the layout, design and construction of these new factories, several topics were very important such as the choice of a settlement close to the forests (wood as fuel), raw materials and water (machinery motor power), in addition to proximity to roads and the towns where the workers lived.
La Real Fábrica de Cristales de La Granja (The Royal Glass Factory in La Granja, Segovia) was built and enlarged along the 18th century. The construction process reveals how the builders made decisions about the distribution of the works for glass manufacturing, considering the position of the kilns, the expulsion of smoke, the lighting, the construction techniques and even places for the workers relaxation.
Brick vaults were erected to avoid fires, and several of them were built without centering. Two large domes function as chimneys. There were 32 sets to temper the glass, and the surplus heat was used to warm the rooms for the workers. The position and orientation of the glass polishing tables were very important because this machinery needed the force of water for moving material and the glass had to be near windows oriented towards West, to facilitate the detection of defects and irregularities. The wooden warehouses were placed closer to the kilns.
The authors have drafted the Master Plan of this building and have studied its history, its construction, its operations, its relationship with other similar factories in Spain and Europe, as well as other issues such as cultural heritage, management, conservation, maintenance, and architectural proposals [1]. This piece will examine both the technical requirements and the construction process of this building.
Pre-industrial modernization in Spain (18th century) and the establishment of the Royal Glass Factory in La Granja
The change of dynasty in the Crown of Spain, with the advent of Bourbons, meant the rise of the Enlightenment ideas, the adoption of the French mercantilism and the introduction of an economical production process. The inspiration for setting up new state-sponsored industries was born in the Manufactures et fabriques du
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royaume, the Manufactures Royales, ruled in 1666 by Jean-Baptiste Colbert, the French finance minister of Louis XIV [2]. Philip V became king of Spain in 1705 and developed a modern and centralized State. One of the pillars of his economy and production was the establishment of the Reales Fábricas, changing the craft production inherited from medieval period. The Royal Factories were located across the territories. The monarchy enacted several laws to protect the national product, imposing fees and granting privileges whilst organising industrial spying and recruiting qualified foreign craftsmen [3].
In 1719, Juan de Goyeneche y Gastón founded the first factory for the production of glass in Nuevo Baztán (Madrid), a new town designed by this businessman in which to establish factory and imbue the workers with rational urbanism (Layuno Rosas 2013). However, due to the increase in the prices of raw materials and foreign competition, the factory had to close down in 1724.
So, in 1727, a new factory was founded in La Granja de San Ildefonso (Segovia). The site, which was not far from Madrid, was surrounded by pine and oak forests to provide fuel. In the beginning, it was only a small oven built by Ventura Sit and Carlos Sac, officials of the first Goyeneche’s factory. Moreover, a new royal palace was being built in this town. For this reason, in 1737 a new building had to be constructed for the new Royal Factory which supplied flat glasses for the windows and mirrors of the palace. The flat glass was first produced by the Venetian method, that is: a cylinder of glass was blown and after it was stretched. However, ca.1736 the new French system was adopted. It consisted of pouring the liquid glass over a bronze table, which allowed the manufacture of larger sizes (Fig. 1). For this reason, French craftsmen were contracted [4].
Fig. 1. Pouring process and bronze table for the flat glass (right) and hydraulic engine to polish the flat glasses by John Dowling (1761) (left). Plates 24 and 34 of the L’art du verre, Encyclopédie of Diderot and D´Alambert
In the vicinity of the royal palace of La Granja, several factories were founded, each one for each production technique, and each one with its skilled workers:
- 1737. Planos, for flat glass for windows and mirrors. Spanish workers.
- 1746. Labrados, for engraving glasses, coups, flowerpots, toys or lamps. French workers.
- 1749. Entrefinos, with German craftsmen who brought the fine Bohemian designs on small windows, glasses, bottles, and lanterns, enlarged in 1770 due to the success of its products, and burned in 1773.
- 1770. Second factory of Planos (flat glass).
The factories were complemented with warehouses for the wood and a building for polishing the glass (1748), which was relocated in 1762 in a new building designed by the Irish engineer John Dowling to accommodate a new and technologically pioneering engine. The technical improvement of this machine reached such popularity that it was reproduced in the Encyclopédie. All these factories needed a water supply, and a network of pipes was built from the springs and rivers in the Royal Gardens to the factories (Fig. 1). The town of La Granja de San Ildefonso (Saint Ildephonse’s Farm) was dominated by Glass production and the workers involved in it. For example, the German workers brought their support for Saint John Nepomuk and built a church for him.
Fig. 2. Plan of the Gardens and Royal Site of San Ildefonso in 1800, by Antonio de Herrera. The water conductions from rivers and springs are drawn over the plan. a. Old factory of vidrios planos (flat glass) (burned in 1770); b. Old Polishing nave; c. Labrados (engraved) and entrefinos (fine glass) factories (burned in 1773); d. Wood store; e. New factory of flat glass (1770); f. Saint John Nepomuk church; g. Royal Palace; h. Royal Gardens
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The factory of flat glass, named La Calandria or Fábrica de Planos (Factory of Flat [glass]), was affected by the fire in 1770. Although it was not destroyed and the production was able to continue, the king Charles III agreed with the aparejador (clerk of works) José Díaz Gamones to build “a new building equivalent to these which was burnt down but with the necessary vaults”.
A fireproof building: functionality and construction
In 1770, José Díaz Gamones drew the layout of this new building, bigger than the old factory and built mainly with brick masonry. The building follows the aesthetic principles of the Enlightenment epoch reflecting the elegance of the new Bourbon dynasty and the rationality of the industrial architecture. The most magnificent part is the ovens nave, placed in the southern part of the building (Fig. 3). There are two big domes where the ovens were placed. Between them, there is a long nave with 30 small vaults for the kilns where the glass was tempered. There are two longitudinal corridors (named atizaderos) at the back of these furnaces from which the fires were controlled.
Fig. 3. South façade of the Royal Factory of Glass of La Granja, with the heraldic emblem of Philip V (photos and drawing: authors)
Fig. 4. First layout of the Royal Factory of Flat Glass in La Granja by José Díaz Gamones in 1770 (AGP)
One central courtyard separated this building from the Polishing nave, that was placed in the north façade. The complex was completed with offices, forge, material stores, stables, waste stores, latrines and dwellings for the workers. The final building differs from this design. The Polishing nave was finally placed in the West façade because the West light (practically horizontal in the afternoon in this latitude) allowed one to check the flatness of the glass and its quality. This change meant that the offices had to be moved, so in 1785 the architect Juan de Villanueva [5] designed a new complex with five blocks in the East façade where, on the ground floor, the rooms for engraving, gilding, storage, and different workrooms were located, whilst on the upper floor there was accommodation for the workers. He also built the wood store in the centre of the factory. The project had also included the northern façade, where ovens for the other three factories of La Granja (one of Grabados or engraved and two of Entrefinos or fine glass) were to be located, but it was never built.
In 1786, a hydraulic machine designed by Demetrio Crow for polishing was placed in this nave. This machine worked for 12 polishing boards, but the masters complained about the broken glasses it provoked, in addition to the necessities of polishing materials (gypsum and sand) and the unequal finishing. Finally, to increase the efficacy of the machine, they built a water pond to guarantee the water flow and pressure.
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Fig. 5. Rests of the hydraulic structures for movement of the machine by Demetrio Crow and Tomás Pérez (1791) (right) and original granite board for polishing (left), that can be seen nowadays (photos: authors)
In 1833 the Crown concluded its support for the production, so the factory passed into private hands. In 1911 the factory suffered an important change in the production because of the implementation of the gasogenous ovens to produce gas fuel from the combustion of charcoal and wood. In this period, the factory functioned, first (1911-1915), as a cooperative business named La Esperanza and, finally (1915-1972), as a limited company. In 1982, the building was rescued from its abandonment, it was restored and a new National Centre for the Glass Foundation was established. The project of rehabilitation included three main activities and spaces in the old Royal Factory: The Technological Museum of the Glass, The Glass School and Historical Glass Research and Documentation Centre. Today, the production still works and a new future can be opened by the proposals of the Master Plan [6].
Brick vaulting as a fireproof construction
The construction of this new and improved factory was thought to avoid fires in the ovens area and to prevent the transmission of the fire. On 20th November 1770, after the burning of the first factory, the construction of a new flat glass factory was approved. José Díaz Gamones was asked to find a plot and construct a new building which would prevent fire [7]. So, the main building in which the two ovens and the atizaderos were placed was built entirely with vaulted construction. Moreover, the craftsmen tried to build without the use of centering and with the minimum cost of auxiliary structures.
In 1770 Díaz Gamones submitted a drawing in which he designed the ovens nave to be built solely from brick vaulting. As he explains, the construction of the principal nave and the parts for ovens “has to be built with brick masonry vaults, due to the fire” (Fig. 4) [8].
The construction began very soon. In 1772 the rhythm was quick (with more than 80 people working amongst brick builders, carpenters, workers…[9]) and in 1773 it seems to be ready to produce in spite of the fact works were not yet finished [10].
In 1774, the central nave with barrel vault (52.60 m long, 10 m wide) was already being built or, at least, was starting to be built (Fig. 5): “to begin with the big nave vault which covers the glass hardener ovens, and having closed the pendentives and transverse arches, to begin with the hemispherical dome, following with the rest of the vaults [11]”. The master builder, José Días Gamones complained that the cost of the work was very high and he had to ask for more money to provide iron for the ties and wood for the centering and scaffoldings [12]. There are no more documents about the construction of these vaults, but these two quotations are very interesting. First, the barrel vault was built employing wooden centerings and iron ties. They finished in the two transverse arches and they began to build the pendentives of the first dome. The brick work in the pendentives between the dome and the nave is more disordered and reveals uncertainty in its construction, in contrast to the rest of the pendentives, which are perfectly built. It seems that at this stage of the construction, they doubted, needed more money and had to make decisions on-site about how to continue. We do not know if they had to change the design or the construction process, but it seems that they improved the quality of the brick work in the rest of the pendentives, perhaps built without centering (Fig. 7).
The barrel vault of the nave is counterbalanced by iron ties. The transverse arches under the domes, in the longitudinal direction of the nave, have two iron ties each one.
Fig. 6. The barrel vault with iron ties of the central nave, after the modern plaster recovering (photo: Fundación Centro Nacional del Vidrio, 1981)
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The domes
The ovens were placed under two brick domes with a lantern (that function as big chimneys) supported by pendentives (Fig. 6). In the dome, eight windows are opened. The diameter is 11,15 m (40 feet), and the profile is a pointed arch with the centres approximately in the thirds of the diameter, following the prescriptions of the treatise Arte y uso de la arquitectura wrote in 1639-1663 by Fray Lorenzo de San Nicolás [13]. The thickness of the dome decreases with the highness.
The two eastern pendentives of the first dome and the four ones of the second dome are built using the same rigging. The first half of the pendentive is built at the same time of the transverse arches. The horizontal rows became progressively curved to accommodate the edges to the radial rigging of the transverse arches. In the middle of the pendentive, a big block of granite is bedded. We cannot know the depth of this block (inside the masonry), and what its function is. Maybe it could be placed to support the scaffolding or it is the device for the geometrical control during construction. Or maybe it is a connexion key between the external face of the pendentive and the filling of the masonry. Over this block, the brick work changes into arches with flat rows amongst them (Fig. 7).
Fig. 7. Second dome of the Royal Factory of Glass (photo: authors)
Fig. 8. Pendentives of the first dome (left) and the second dome (right), in where we can see the change of brick rigging and the use of iron connector in the first one (photo: authors)
In the domes, bricks are laid in horizontal rings, whose interior face follows the radius of the dome. A dome can be built in horizontal rows since when each ring is complete it is perfectly stable. It can be built from the back, so there is a saving in scaffolding and falsework.
In any case, a geometrical control of the construction is always required, which in this case would be a sort of mobile wooden structure that marks the radius and position of each brick. Given that the dome starts at a 13 m height, it is plausible that a sort of scaffolding would be erected up to this point, possibly anchored to the pendentives (this could explain the fact that there are some granite blocks embedded and, at least in the first dome, some metal reinforcements). On this platform, a mobile device could be placed to mark the profile of the dome as a geometric control mechanism.
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Fig. 9. Axonometric view of the dome and vaults (drawing by IJGC). a. furnace for melting the glass mass; b. melting pot with the glass mass; c. bronze board for pouring the glass mass to do the flat glasses; d. ovens for tempering the glass; e. Atizaderos (fire set) and corridor; f. chimney; g. lantern-chimney in the dome; h. dome; i. iron ties; j. oculus and illumination windows; k. stairs to the forge; l. auxiliary corridors to offices and material supply; m. communication with the polishing nave
In the exterior, the domes have an octagonal volume with a pitched tile roof. There are 4-5 cm iron ties for the reinforcement inside the masonry on the outside. This iron reinforcement is formed by two perimeter ties that are connected by vertical bars in the corners. These two octagonal chains anchor the dome and are placed behind the windows and in the upper part (Fig. 10).
Fig. 10. Detail of the iron reinforcement of the domes (drawing by IJGC)
The vaults of the descansaderos (break rooms)
Along the central nave, 15 small vaults for tempered glass ovens are placed on each side. Over them thirty rest rooms have been built for the workers which take advantage of the heat of the ovens. The rest rooms have a rectangular floor plan of 4 x 2.40 m. These contain barrel vaults to support the roof, which means there is no wooden structure which could burn. The brick work starts with radial rows of bricks until they reach more or less the half of the high of the vault. Then, the brick bond changes into herringbone brickwork.
The construction of the barrel vault starts with several rows set in parallel to the walls, with the bricks laid in radial sense. More or less at half height of the vault, the bricks change their orientation to 45º. Gradually, these rows are counterbalanced by leaning on each other until the space to be covered is completely closed (Fig. 11). This construction technique is very old, and we can link it with the tradition of brick vaults without centering that was born in Mesopotamia, that Byzantine architecture developed and the vernacular tradition has preserved in Spain and in the Mediterranean area.
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Fig. 11. Brick vault of one of the break rooms or descansadero (photo: authors)
Conclusions
We have shown a good example of the rational and industrial architecture of the Enlightenment in which the function and the form are inherently linked. Moreover, the concern for fire (above all, after the burning of the early factory in 1770) led architect José Díaz Gamones to choose a place to establish the new Royal Factory away from the city walls and to build the ovens nave entirely from brickwork masonry.
This brickwork of fireproof construction developed a complex system of domes and vaults avoiding the use of any timber. During the construction, the builders had funding problems because of the use of wooden formworks and centering for the barrel vault of the nave. Decisions about the construction process had to be taken on site which could well be the reason for the change of the pendentives’ rigging, defining a rational (and actually beautiful) brickwork in the second dome pendentives.
Finally, the spatial configuration of the ovens nave is very intelligent and skilfully resolved the problem of ventilation and smoke removal and the illumination of the workplaces.
Abbreviations
AGP: Archivo General de Palacio (Royal Palace General Archive, Madrid)
AP: Administraciones Patrimoniales (Heritage Administrations, a section of the archive)
RFC: Real Fábrica de Cristales (Royal Factory of Glass, a collection of the archive)
References [1] Estefanía Herrero-García (Ms. arch.) is the Project Manager for this Master Plan of the Royal Factory of Glass
of La Granja. The work was commissioned by the Instituto de Patrimonio Cultural de España (Institute of Cultural Heritage of Spain) of the Ministry of Culture. Ignacio-Javier Gil-Crespo (PhD Arch.) leaded the Architecture and Construction area. The rest of the team was formed by Pablo Beltrán Rodríguez (Technical Arch.), Vanesa García Alcocer (Ms. Arch.), Santiago Huerta (PhD Arch.), Leopoldo Matienzo (Arch.), Clara Martín García (Archeologist), José Miguel Labrador Vielva (Archeologist), Juan Claver Gil (Arch., PhD in Industrial Engineer), Carolina Castañeda López (PhD Arch.), Miguel Ángel Sebastián Pérez (PhD Industrial Engineer), Santiago Herrero Mas (Lawyer), Luis Alberto Martín de Frutos (Geologist), Álvaro Saugar López (Computer Engineer).
[2] N. Fouquet, Histoire de la vie et de l’administration de Colbert, Paris: Guillaumin, libraire; 1846. G. Zeller, L’industrie en France avant Colbert. Rev D’histoire Économique Soc. 1950;28(1):3–20. P. Deyon and P. Guignet, The Royal Manufactures and Economic Progress in France before the Industrial Revolution. J Eur Econ Hist. 1980;9(3):611–9.
[3] J. Vigo, Reales Fábricas, Madrid; 1959. A. Rabanal Yus, 'La industria y los sitios Reales', El Real Sitio de Aranjuez y el Arte Cortesano el siglo XVIII, Comunidad de Madrid; 1987. p. 301–8. G. Otero, Reales Fábricas, una utopia razonable. MOPU. 1988;No 356:134–45.
[4] M. Rico y Sinobia, Historia del Trabajo del Vidrio, Sus artífices en España. In Madrid: Imprenta y Estereotipia de M. Rivadenyra; 1873. (Almanaque del Museo de la industria). Pastor Rey de Viñas P, Historia de la Real Fábrica de Cristales de San Ildefonso durante la época de la ilustración (1727-1810), La Granja de San Ildefonso: Fundación Centro Nacional del Vidrio; 1994. Pastor Rey de Viñas P. Los extranjeros en las Reales Fábricas de Cristales de La Granja de San Ildefonso (siglo XVIII). In: Cabañas Bravo M, (Ed.), El arte foráneo en España: presencia e influencia. 2005. p. 127–38.
[5] Juan de Villanueva (1739-1811) was the most important neoclassical architect in Spain. He also built, committed by King Charles III, the Prado Museum, Astronomical Observatory, the Royal Botanical Garden, several buildings in El Escorial, amongst other important 18th century buildings.
[6] For further information about the Royal Factory, there are several publications by Paloma Pastor Rey de Viñas, María Jesús Callejo Delgado and others: Callejo Delgado MJ. La Real Fábrica de Cristales de La Granja. R Sitios. 1986;(88):45–52. Callejo Delgado MJ. La Real Fábrica de Cristales y Espejos de Madrid. An Inst Estud Madr. 1986;XXIII:201–6. Ruiz Hernando JA, Callejo Delgado MJ. Las fábricas de vidrio de La Granja. Estudio arquitectónico, Vidrio de La Granja: Real Fábrica de Cristales de La Granja de San Ildefonso, Madrid: Ministerio de Cultura, Dirección General de Bellas Artes y Archivos; 1988. p. 33–55. Pastor Rey de Viñas, Paloma. La Real Fábrica de Cristales de La Granja. Historia. Repertorios decorativos y tipologías formales. Ávila: Global, consejeros de comunicación; 1998. Pastor Rey de Viñas, Paloma, Estebaranz, Acu. La Real Fábrica de Cristales. Imágenes de una época. San Ildefonso (Segovia): Fundación Centro Nacional del Vidrio, Mañana Más, Aldeasa; 1999. Pastor Rey de Viñas P. La Sociedad Esperanza, arrendataria de la Real Fábrica de Cristales, 1911-1960, Actes Museu d’Arqueologia de Catalunya. 2001. p. 241–8. Pastor Rey de Viñas P. Reales fábricas de cristales de San Ildefonso. In: Torreguitart Búa S, (Ed.), Jornadas sobre las Reales Fábricas (2002 La Granja de San Ildefonso). Torreguitart Búa, Susana (coord.); 2004. p. 201–26. Pastor Rey de Viñas P. La Real Fábrica de Cristales. In: Egaña Casariego F (Ed.), Vidrio y cristal de La Granja: colección Laguna-Lomillos. Egaña Casariego, Francisco (coord.); 2009. p. 39–53.
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Pastor Rey de Viñas P. Máquinas hidráulicas en la Real Fábrica de Cristales de La Granja (s. XVIII- principios s. XIX). In: Actas V Congreso Internacional de Molinologia. 2009. p. 137–40. Callejo Delgado, María Jesús, Pastor Rey de Viñas, Paloma. Las Reales Fábricas de Cristales de La Granja de San Ildefonso. Un recorrido por sus edificios. Ayuntamiento de San Ildefonso - La Granja: Exmo. Ayuntamiento de San Ildefonso - La Granja, Diputación Provincial de Segovia, Cámara Municipal da Marinha Grande, Agate - Agence Tarnaise de Développement; 2004.
[7] “Llame usía a Díaz, entérele de esta orden, y digale que procure elegir el terreno compatible con el passeo, con el adorno y precaber del incendio los montes, y que en el plano que se forme haga demostraciones de todos estos respectos” (AGP, AP, RFC, box 813, file 3; also cited by Ruiz Hernando and Callejo, note 6).
[8] "Lo que va en el plano sombreado con linia Roja que es en donde van los dos ornos templadores, carquesas y nabe principal cuia obra ha de ser de fabrica de Bobedas de Rosca de ladrillo por la contingencia de fuego" (AGP, AP, RFC, box 809, file 10).
[9] AGP, AP, RFC, box 813, file 1. [10] Between 1773 and 1774, between the salaries of the glass craftsmen and the factory material, we can still
[11] “Empezar la Boveda de la nabe grande que cubre las Carquesas o templadores, y haver cerrado las pechinas y Arcos torales para el empiezo de una media naranja y continuado en las demas bovedas para su adelantameinto” (AGP, Legajo 4, Fábrica de Cristales, cited by Ruiz Hernando and Callejo, note 6).
[12] José Díaz Gamónes wrote a letter asking for money to Miguel de Múzquiz (Minister of Finances of Charles III and superintendent of the Royal Factory) because he had to use “mucho fierro para su atirantamiento, Maderas para Zimbras y andamios que son precisos y la mayor altura” (AGP, Legajo 4, Fábrica de Cristales, cited by Ruiz Hernando and Callejo, note 6).
[13] B. Morchón Hernández, Diseño y construcción de la bóveda de media naranja de ladrillo a finales del S. XVIII: Real Fábrica de Cristales de La Granja (Segovia). In: Actas del Octavo Congreso Nacional de Historia de la Construcción Madrid, 9-12 de octubre de 2013. Madrid: Instituto Juan de Herrera; 2013. p. 717–25. B. Morchón Hernández, La bóveda de media naranja del crucero oeste de la nave de hornos de la Real Fábrica de Cristales de La Granja. Cuad Vidr. 2013;1:1–13.
