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The quality of the cement used is not immaterial. Of these 

 there are two kinds the " quick-setting" and the " slow-setting " 

 cement. The former are generally natural cements, containing 

 variable proportions of lime ; whereas the slow-setting cements are 

 generally artificially manufactured with definite proportions of lime, 

 which varies from 58 to 63 per cent., and are burnt without excess. 

 It is said that this regularity of composition, and the way they are 

 manufactured, insures their more lasting properties. Slow-setting 

 cements containing less lime than some of the quick-setting ones, 

 all the lime is taken up by the clay and transformed into aluminate 

 of calcium, and no free lime is left uncombined, which would, in 

 contact with wine, rob it of some of its natural acids and cause it to 

 go flat. 



When cement vats are used for storing wine, a top is constructed 

 to them in the shape of a vault, and a manhole made of cast-iron, 

 with a tight-fitting door, is set in the structure. It is also some- 

 times advisable to line the inside with china or glass tiles. The 

 St. Gobain Company, near Paris, manufactures for this purpose 

 glass tiles 4 to 6 mm. in thickness and 24 cent, by 24 cent. The 

 side which is against the cement is striated, to better hold to the 

 cement, whilst the other side is smooth. For the floor, larger and 

 thicker tiles are used. These tiles are set in soft cement mortar, 

 and care should be taken not to allow any air to remain between 

 the cement and the tile, which should be soaked in water before 

 using. 



Apart from these brick and cement vats, some are constructed 

 of a combination of iron and cement, and are extensively used in 

 Algeria. They are known as sidero-cement vats, and consist of a 

 framework of iron' rods, either rectangular or cylindrical, as desired. 

 On this iron lattice-work, which has the shape of the vat, cement 

 mortar is plastered, and the desired polish is given to the surface. 



These vats are much thinner than the brick ones, whilst their 

 cohesion is much greater, for although cement can stand a con- 

 siderable crushing strain, it lacks in cohesion, or in other words, its 

 tensile strain is not so great. 



In Algeria, where these sidero-cement vats are in great favour, 

 the cost is set down as ranging between 2s. 6d. to 3s. 4d. per hec- 

 tolitre (22 gallons) for small vats, and less for larger ones. 



The combination of the iron and the cement, instead of being 

 an element of weakness, considerably adds to the strength and 

 durability of the vats. Both these substances expand or contract 

 at the same rate, and therefore no dislocation ensues, whilst, on the 

 other hand, the close fitting cement covering effectually preserves 

 the iron from rusting. 



When these cement vats are made, and dry, they are first filled 

 with water, and, although they may sweat a little first, this soon stops. 



It is necessary before using these vats to also wash them with 

 some solution which will dissolve and neutralise the traces of lime 

 which may be left close to the surface. 



