224 On a Mode of erecting light Vaults 



DESCRIPTION OF A MODE OF ERECTING LIGHT VAULTS 

 OVER CHURCHES AND SIMILAR SPACES. 



BY M. DE LASSAUX. 



(Communicated by Professor WHEWELI>, of Cambridge.) 



"IY/T DE LASSAUX, of Coblentz, architect to the King of 

 Prussia, is the discoverer and restorer of this process, 

 and gives the following account of his investigations. 



He had arrived in various ways at the conviction that what 

 are called the gothic and ante-gothic styles of architecture (the 

 pointed arch and round arch styles), are not only the most 

 appropriate for churches, but also the cheapest. He had 

 attempted to discover some easy means of erecting stone vaults 

 in such cases, thinking them highly desirable, whenever the 

 funds at the builder's disposal will permit them. Vaults which 

 are at the 'same time wide and light, belong incontestably to 

 the boldest and most ingenious of human inventions : they are 

 peculiarly suitable in religious edifices ; they are secure from 

 the devastations of fire; and, when introduced in public build- 

 ings, they correspond to the spirit of the celebrated decree of 

 the republic of Florence, enacted in the year 1294, that all 

 which is executed for the commonwealth should bear the lofty 

 impress of the common will. 



M. de Lassaux was also aware, that at Vienna, at the pre- 

 sent time, very wide and flat domes are erected almost entirely 

 free-handed (i. e. without centering), and that in the neigh- 

 bourhood of that city, very flat ovens and wide mantlepieces * 

 are constructed almost in the same manner, and with the help 

 only of a few slight posts or poles. He endeavoured, there- 

 fore, to discover some mode of facilitating, by similar means, 

 the execution of wide vaults in churches. 



His attempts for some time led him to nothing bearing on 



* Brunelleschi constructed the cupola of the church of Santa Maria del Fiore 

 at Florence, without a centre. J. S. ' At Bassora, where they have no timber 

 but wood of the date tree, which is like a cabbage-stalk, they make arches without 

 any frame. The mason, with a nail and a bit of string, describes a semicircle on 

 the ground, lays his bricks, fastened together with a gypsum cement, on the lines 

 thus traced, and having thus formed his arch, except the crown brick, it is care- 

 fully raised, and in two parts placed on the walls. They proceed thus till the 

 whole arch is finished ; this part is only half a brick thick, but it serves to turn a 

 stronger arch over it.' Eton's Survey of (he Turkish Empire. J. S. 



