912 STONE 



layer or lamina upon its face, of a thickness corresponding to the depth of the border. 

 Only a thin metal film is left upon the back of the mould. The dipping-pan is sus- 

 pended, plunged, and removed, by means of a powerful crane, susceptible of vertical 

 and horizontal motions in all directions. When lifted out of the bath, it is set in a 

 water-cistern, upon bearers so placed as to allow its bottom only to touch the surface. 

 Thus the metal first concretes below, while by remaining fluid above, it continues to 

 impart hydrostatic pressure during the shrinkage attendant on refrigeration. As it 

 thus progressively contracts in volume, more metal is fed into the corners of the pan, 

 in order to keep up the pressure upon the mould, and to secure a perfect impression, 

 as well as a solid cast. 



The whole process is greatly improved by the employment of a prepared bibulous 

 paper, instead of the plaster-of-Paris. The paper employed was originally of French 

 manufacture, but is now made in England. Four sheets of tissue and one sheet of 

 brown paper being pasted together, it forms one sheet. The form of type being ready, 

 a sheet of this prepared paper is placed upon it, and it is then beaten into the face of 

 the type by hard hand-brushes. It is then filled in the blank parts with paste, when 

 the whole is then covered by a thicker sheet of paper, and it is then passed under a 

 heated press for about two minutes to dry. On removing the paper it is found to have 

 received a most perfect impression of the type. This impressed paper mould is then 

 placed in an iron box, which is fixed in a nearly vertical position, and the heavy cover 

 being carefully closed, there only remains between it and the mould exactly the space 

 which is necessary to ensure a proper thickness to the type-metal. All being prepared, 

 the melted metal is poured into the mould. It flows, of course at once to the bottom 

 of the mould, and as the liquid is rapidly supplied, the whole is filled, and, as in the 

 case already given, some pressure is obtained by the head of metal above the paper- 

 mould. The mass of metal (iron) forming the casting box, in comparison with the 

 thin plate of type-metal, ensures a rapid chilling of the latter, so that the plate can be 

 removed in a very short time. The impression thus obtained is exceedingly perfect ; 

 and the whole piocess is one of great simplicity and exactness, and is capable of being 

 executed with great rapidity. 



' The Times ' and other daily newspapers are regularly printed from stereotype- 

 plates ; but most of the machines for taking the matrices, were invented by Mr. 

 Sweet, at ' The Times ' office, and save one half of the time used by beating the form 

 with brushes, each plate being cast and placed on the machine in about a quarter of 

 an hour. 



The advantages of a solid block over a form of loose type will be sufficiently 

 obvious to all ; and, but for the security which is afforded by the use of the solid plate, 

 there would be great risk in driving the printing machinery at such high rates of 

 speed as are employed in ' The Times ' office and other offices, where they require to 

 throw off a very large impression within a very limited time. See PRINTING and 

 PRINTING MACHINERY. 



STXIiXi. See DISTILLATION. 



STIPPIiE ENGRAVING is a process which was practised by Bartolozzi, Ry- 

 land, .and others, in imitation of chalk-drawings of the human figure. Stipple is per- 

 formed with the graver, which is so managed as to produce the tints by small dots, 

 rather than by lines, as in the ordinary method. It is very soft in its effect, but 

 inferior to the more legitimate mode of engraving. See ENGRAVING. 



STOCKING MANUrAC-TITOE. See HOSIERY. 



STONE is earthy matter, condensed into so hard a state as to yield only to the 

 blows of a hammer, and therefore well adapted to the purposes of building. Such 

 was the care of the ancients to provide strong and durable materials for their public 

 edifices, that but for the desolating hands of modern barbarians in peace and in war, 

 most of the temples and other public monuments of Greece and of Rome would have 

 remained perfect at the present day, uninjured by the elements during 2,000 years. 

 The contrast, in this respect, of the works of modern architects, especially in Great 

 Britain, is very humiliating to those who boast so loudly of social advancement; for 

 there is scarcely a public building of recent date which will be in existence one thou- 

 sand years hence. Many of the most splendid works of modern architecture are 

 hastening to decay, in what may be justly called the very infancy of their existence. 

 This is remarkably the case with the bridges of "Westminster and Blackfriars ; the 

 foundations of which began to perish most visibly in the very lifetime of their con- 

 structors. 



Stones for building, it is stated, may be proved as to their power of resisting the 

 action of frost, by the method, first practised by M. Brard, and afterwards by 

 MM. Vicat, Billaudel, and Coarad, engineers of the bridges and highways in France. 

 The operation of water in congealing within the pores of a stone may be imitated by 

 the action of a salt, which can increase in bulk by a cause easily produced ; such as 



