692 



RAISINS 



Tlie manufacture of iron and steel rails has, with the extension of our 

 railway system, increased in a remarkable manner. This is, however, rather a subject 

 for a treatise on mechanical engineering, than for a Dictionary of Manufactures. 



Kails are made by passing bars of iron, when red hot, through rollers with indenta- 

 tions or grooves in their peripheries, corresponding with the intended shape of the rails ; 

 the rails thus formed present the same surface to the bearing of the wheels, and their 

 depths being regulated according to the distance from the point of bearing, they also 

 present the strongest form of section with the least material. 



Malleable iron rails were formerly always employed. An objection has been urged 

 against these rails on the ground that the weight on the wheels rolling on them 

 expanded their upper surface, and caused it to separate in thin laminae. In many of 

 our large stations rails may be frequently seen in this state ; layer after layer breaking 

 off, but this may be regarded rather as an example of defective manufacture than any- 

 thing else. It is true, Professor Tyndall has referred to those laminating rails, as 

 examples in proof of his hypothesis, that lamination is always due to, and is always 

 produced .by, mechanical pressure upon a body which has freedom to move laterally. 

 Careful examination, however, shows that whenever lamination of the rail becomes 

 evident, it can be traced to the imperfect welding together of the bars of which the 

 rail is formed. 



The weight of railway bars varies according to section and length. There are some 

 of 40 pounds per yard, and some of 80 pounds, almost every railway company em- 

 ploying bars of different weight. Beside flat rails, which are occasionally still used, 

 we have bridge rails employed, which have the form of a reversed U . These have 

 sometimes parallel aides, or, as in dovetail rails, the sides are contracted. The -rails 

 are more easily manufactured than the I-rails, the difficulty of filing the flanges not 

 being so great as in the latter rail. 



Fig. 1700 represents the old rail, and fig. 1701 Mr. W. H. Barlow's patent rail, 

 which is made to form its own continuous bearing. In section this rail somewhat 

 resembles an inverted V, with its ends considerably turned outwards. This portion 

 forms the surface by which the rail bears upon the ballasting, the apex of the A being 

 formed with flanges in the ordinary form of rails : and the rail, therefore, beds 



1700 



1701 



throughout on the ballast. Eails of Vignole's section are now extensively employed. 

 Steel rails, especially those made from Bessemer steel, are becoming very generally 

 used. They are found to wear very much longer than the iron rail, and are specially 

 useful at points, crossings, and stations where the wear is exceptionally heavy. 



RAISIN'S are grapes allowed to ripen and dry upon the vine. The best come 

 from the south of Europe, as from Koqueviare in Provence, Calabria, Spain, and 

 Portugal. Fine raisins are also imported from Smyrna, Damascus, and Egypt. Sweet 

 fleshy grapes are selected for maturing into raisins, and such as grow upon the 

 sunny slopes of hills sheltered from the north winds. The bunches are pruned, and 

 the vine is stripped of its leaves, when the fruit has become ripe; the sun then 

 beaming full upon the grapes completes their saecharification, and expels the 

 superfluous water. These are muscatels or blooms. The raisins called lexias are 

 plucked, cleansed, and dipped for a few seconds in a boiling lye of wood-ashes 

 and quicklime, at 12 or 13 of Beaumi. The wrinkled fruit is lastly drained, 

 dried, and exposed in the sun upon hurdles of basket-work during 14 or 15 days. 



The finest raising are those of the sun, so called; being the plumpest bunches, 

 which are left to ripen fully upon the vine, after their stalks have been half cut 

 through. 



Valentia raisins are prepared by steeping them in boiling water, to which a lye of 

 vine stems has been added. 



Corinthian raisins or currants are obtained from a remarkably small variety of 

 grape called the black Corinth. They are now grown in Zante, Cephalonia, and 

 Patras. 



