184-9.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



the Dog-e's palace — that the steps which the robed senators and 

 great men of the Republic were accustomed to ascend could not 

 be too rich or too nobly ornamented. On these steps, for the pur- 

 pose of producinsf a contrast with the white marble, an inlay of 

 metal was formerly introduced. Spoiled of these to-day, it is 

 still an object of great admiration. The huge, rough, but expres- 

 sive, tutelary divinities on the summit — emblems of the naval and 

 military prowess of Venice — by Jacobo Sansovino, impart to it a 

 high degree of interest, and have conferred upon it much of its 

 celebrity. They were placed upon their present pedestals about 

 the year 1566, though commenced by him some years previously. 



The Giants' Stairs is vivid in the recollection of all who have 

 seen it, and has been copied and contemplated by generations of 

 artists. It has been a favourite study with our Prouts, our 

 Leitches, our Stantields, and our Turners. It abounds in histori- 

 cal and romantic associations; and no one who has read the history 

 of the Doges, but would remember it was these marlde stairs 



" Down which the grizzly head of old Faliero 

 Koll'd from the block." 



From Temanza's "Life of Sansovino,"* we have collected some 

 of the fcdlovving particulars of this excellent sculptor and archi- 

 tect. He was born in Florence, about 1479 ; died, aged 91, 1570. 

 His first studies were from the well-known cartoon by Michael 

 Angelo (the War of Pisa), which was ordered to be drawn for a 

 painting in the Council-hall at Florence, and which Michael An- 

 gelo gained in competition over Leonardo da Vinci. It was a 

 great object of study among the students of the day, and Sanso- 

 vino upon this masterly production laid much of his foundation of 

 drawing the figure, and knowledge of design. From Florence he 

 repaired to the Eternal City, where he studied the Apollo Belvi- 

 dere, &c. Bramante, then the Pope's architect, seeing Sansovino 

 modelling in the Vatican, and pleased with a small vase which he 

 held in his hand, that served him as an inkstand, and wliich he had 

 designed, ordered him to model in wax from the celebrated statue 

 of the Laocoon ; giving the same example to three other young 

 artists likewise to copy. Raphael was to decide as to which was 

 the best among the four, and his approbation fell upon Sansovino. 

 This model was cast in metal, and was considered to be a most 

 perfect specimen. At this period, Sansovino derived advantages 

 from his inhabiting the same house with San Gallo, being in conse- 

 quence induced to go through a course of architectural studies. 

 Subsequently, he was with Pietro Perugino, and enjoyed the com- 

 pany of the first literati and architects of the day, among whom 

 was Cesare Cesariano (the commentator of Vitruvius), and Andrea 

 del Sarto. The praises he now received, and the fame he acquired 

 as a sculptor, though little more than the age of thirty, served as 

 a stimulus to exert his talents and produce works from which he 

 might command higher and yet higher commendation. Temanza 

 says (note. p. 13), it is not easy to fix the true period in which 

 Sansovino came to Venice. Vasari places it in 1527, after the 

 sacking of Rome. In Venice he met with congenial spirits, and 

 the friendship of Aretino and Titian ; upon which Temanza truly 

 remarks — "£■ tutti e tre formarono vn Triunwirnto in cut trovavono /e 

 bell' Arti come la lor residenza" (p. 15). In 1529, Buono, the archi- 

 tect of the Proeuratie, dying, Sansovino was posted in his stead, 

 with a provision from the State, and a house near the Orologia, on 

 the Piazza. He was considered to have shown some skill in the 

 mode in which he repaii-ed, by means of circles of iron toothed and 

 wedged, the cupola of St. Mark, which liad been dilapidated for 

 many years. Some of the work was assigned to him in the school 

 della Misericordia, and in the church of S. Francesco della Vigna, 

 though the elevation is Palladio's ; and very beautiful are his 

 bronze bassi-retievi to the doorway in the chapel royal of St. Mark, 

 which are given by Cicognara in the 2nd vol. of his "Storia suUa 

 Scultura." He built anew the Zecca, in 1535, which is constructed 

 entirely of stone from Istria. The admired Loggia, at the foot of 

 the Campanile, was erected about 1540; the pedestals, architraves, 

 and cornices of which are of the beautiful ronso of Verona, the 

 columns of the best Brescia and Grecian marbles, and the remain- 

 der of Carrara marble. It is richly adorned with statues, in niches, 

 of Pallas, Apollo, Mercury, and Peace; and bassi-relievi, emblema- 

 tical of the States of the Republic. The greater part of this most 

 elegant building is by Sansovino; the rest by his pupils. 



Frederick Lvsh. 

 * Fublisllcd in Venice, 1752, quarto, with portrait, engraved from a painting by Titian. 



IMPROVED SAFETY-VALVES. 



By Alfred Gregory, Esq., C.E 



Fig. 1. 



r^^^^i 



Fig. 2. 



The above engraving shows an improved form of safety-valve 

 for steam-boilers, invented by Mr. Alfred Gregory, and described 

 in the Mechanic's Magazine, wliich has met with tlie approbation of 

 several eminent engineers. 



The advantages do not require to be much insisted on. The 

 practice of overloading the safety-valve is much more common 

 than is generally supposed : sometimes it is the act of ignorance, 

 but most frequently that of will, not only endangering life, but 

 injuring ihe pocket also, in the destruction (which is very serious) 

 that ensues to the boilers, fire-boxes, &c. The number of fines 

 levied on locomotive-enginemen furnishes sufficient evidence of 

 the frequency of its occurrence. 



Description. — Fig. 1, represents the safety-valve in a form appro- 

 priate for stationary use. Fig. 2, another modification, on the 

 same principle, applicable to boilers of every description — locomo- 

 tive, marine, and stationary. 



A A, fig. 1, represent the top plates of boiler; B B, the steam 

 space inside; C, the ordinary conical valve, having a perpendicular 

 spindle, to which a weight, D, is attached; E E, valve-box; F F, 

 a chain, which is connected to the valve at one end, and at its 

 other end to the short curved part of the lever G; H is a regulat- 

 ing weight; I, a shield to protect the valve from injury or Inter- 

 ference; e, e, e, e, four bars or stops to the shield I, for frustrating 

 any attempt to damage the valve. 



The mode of working is, for the steam to raise the valve, as 

 usual, when its pressure exceeds that of the weight D, less the 

 lifting power of the lever G, and weight H. The weight D, 

 being inside the boiler, cannot be for any mischievous purpose got 

 at ; and it is equal to the extreme pressure allowed upon the boiler, 

 or may be made so by hanging weights to the eye-loop of D, which 



