254 



EMBOSSING 



EL VANS. Granitic and fclspathic porphyritic rocks, which are frequently found 

 traversing both tho granite and slate rocks. 



'The elvans or veins of quartziforous porphyry that is, a granular crystalline 

 mixture of felspar and quartz, which are common both in Cornwall and Devon, and 

 near tho granite of tho south-east of Ireland are probably in reality granite veins, 

 or veins proceeding from a granitic mass.' Jukes, 



1 When those granite veins are of a large size they are termed Elvan courses ; indeed, 

 this is the only distinction between these two forms of elongated masses of granitic 

 rock. In composition these elvans are either shorl rock, eurite, felsparite, or even 

 varieties of fine-grained granite.' Boose. 



ELYTRA. The horny wing-cases of beetles, formed by tho anterior wings 

 becoming hardened, and therefore useless for flight. Tho brilliantly-coloured and 

 iridescent elytra of some beetles are used for ornamental purposes. 



ElVTAIL OltXBRAlffT. A process which consists in flooding coloured but trans- 

 parent glazes over designs stamped in tho body of earthenware or porcelain. A plane 

 surface is thus produced, in which the cavities of the stamped design appear as 

 shadows of various depths, tho parts in highest relief coming nearest the surface of 

 tho glaze, and thus having the effects of the lights of the picture. This process was 

 introduced by the Baron A. Do Tremblay of Rubelles, near Melun. 

 EMAUX CLOISONNES. Sec ENAMELS. 



EiYTBAIilYllNG. (EmbaumowJit, Fr. ; Einbalsamirunff, Ger.) An operation 

 employed by the ancients to preserve human bodies from putrefaction. From their 

 using balsams in the process, the name was derived. See DISINFECTION ; PUTRE- 

 FACTION. 



ElVTBOLITE. A chloro-bromide of silver found in Chili and Mexico. It varies 

 in colour from an asparagus green to an olive green, is perfectly malleable, and of 

 resinous lustre. The ratio of the chlorine to the bromine appears to vary indefinitely, 

 those varieties which are of a yellow or of a deep green tint being the richest in 

 bromine. Tho name is derived from en&6\iov, intermediate, in allusion to tho mineral 

 being intermediate in chemical composition between the chloride and the bromide of 

 silver. 



EMBOSSING. One of the plans introduced for EMBOSSING CLOTH by machinery 

 which appears to be the most effective, is that of Mr. Thomas Greig, of Rose Bank, 

 near Bury. This machine is thus constructed : 



Figs. 822, 823 represent three distinct printing cylinders of copper, or other suitable 

 material, A, B, c, with their necessary appendages for printing three different colours 

 upon the fabric as it passes through the machine ; either of these cylinders, A, B, or c, 

 may be employed as an embossing cylinder, without performing the printing process, 

 or may be made to effect both operations at the same time. 



The fabric or goods to 

 bo operated upon being 

 first wound tightly upon 

 ;i roller, that roller is to 

 bo mounted upon an axle 

 or pivot, bearing in .-inns 

 or brackets at the back of 

 the ni;ichinc, MS si' 

 D. From this rolln 1 the 

 fabric a, a, a, a, is con- 

 ducted between tension 

 rails, and passed under 

 the bed cylinder or paper 

 bowl E, and from thence 

 proceeds over a carrier 

 roller F, and over Mt-.-itn- 

 boxes not shown in the 

 drawing, or it may b'-cun- 

 ducted into a hot room, 

 for the purpose of drying 

 the colours. 



Tho cylinders A, n, and 

 c, having either engraved 

 or raised surfaces, are connected with feeding rollers A, /;, /, revolving in the ink or 

 coloured troughs c, c, c ; or endless felts, call..! rierw, may be employed, as in >nli- 

 nary printing machines, for supplying the colour, when the device on the trerfoee <>t 

 the cylinders is raised; these cylinders maybe furnished with doctors or scraper!, 

 when required, or the same may be applied to endless felte. 



