SAND 



749 



The salt produce of the United Kingdom is shown in the following returns : 



The Quantities of Cheshire Rock Salt and White Salt sent down the River Weaver in 

 each of the last five years were : 



Droitwith and Stoke Prior produced about 276,000 tons each year ; and the salt- 

 mines in Ireland about 20,000 tons annually. The total produce of the United 

 Kingdom being a little up or down of 1,500,000 tons, and of this about 700,000 tons 

 are annually exported. 



Salt exported in 1874: 828,964 tons ; value, 663, 451/. 



SALTS. It may be sufficient to state here that the common acceptation of a salt 

 is that of a crystallised substance. Those formed by the union of simple bodies, as 

 chlorine and sodium, iodine and iron, or the like ; or of those formed by substances 

 already compound, as sulphuric acid (sulphur and oxygen), with soda (sodium and 

 oxygen), &c. ; or, in the case of many of the salts formed from the organic acids 

 exhibiting a yet more complex constitution. 



Modern chemists define a salt as a body obtained from an acid by replacement of 

 its hydrogen by a metal ; thus, common salt may be derived from hydrochloric acid, 

 or chloride of hydrogen, by replacing the hydrogen by sodium. 



Salts may bo either neutral, or such as do not exhibit any acid or alkaline pro- 

 perties ; or acid, i.e. those in which there is an excess of acid ; or basic, in which there 

 is present more than one equivalent of base for each equivalent of acid, 



SALT, SEDATIVE, is boracic acid. 



SALT WATER, DISTILLATION OF. See WATER. 



SAND (Eng. and Ger. ; Sable, Fr.) is the name given to any mineral substance 

 in a hard granular or pulverulent form, whether strewed upon the surface of the 

 ground, found in strata at a certain depth, forming the beds of rivers, or the shores 

 of the sea. The siliceous sands seem to be either original crystalline formations, like 

 the sand of Neuilly, in 6-sided prisms, terminated by two 6-sided pyramids, or the 

 debris of granitic, schistose, quartzose, or other primary crystalline rocks, and are 

 abundantly distributed over the globe ; as in the immense plains known tinder the 

 names of deserts, steppes, landes, &c., which, in Africa, Asia, Europe, and America, 

 are entirely covered with loose sterile sand. Valuable metallic ores, those of gold, 

 platinum, tin, iron, titanium, often occur in the form of sand, or mixed with that 

 earthy sxxbstance. Pure siliceous sands are very valuable for the manufacture of 

 glass, for ameliorating dense clay soils, for moulding, and many other purposes. 



Specimens of the finer kinds of saud, from the Isle of Wight, and the neighbour- 

 hood of Lynn, are remarkably white and beautiful. Eeigate also furnishes pure 

 siliceous sand. By far the finest samples of sand ever seen in this country were in the 

 American department of the Great Exhibition of 1851, and did not fail to attract the 

 .notice of those interested in such matters. This sand was totally free from iron 

 and every other source of contamination. It was as white as snow ; and so far as the 

 making of glass is concerned, no sand is equal to it : considerable quantities have been 

 imported since that period. The principal sources of sand for the manufacture of 

 glass are Charlton, Hastings, Derbyshire, Alum Bay, Yarmouth, Isle of Wight, 

 Reigate, and Hartwell near Aylesbury, in England ; near Llandudno, in Wales ; and in 

 Limerick, Cork, and Donegal in Ireland. These sands have all more or less of a yellow 

 topaz hue, indicating oxide of iron, and which imparts to all glass the green tinge so 

 very perceptible in the common window variety. To remove this oxide of iron from 

 sand, has never yet, wo believe, been attempted; though if wo may judge by the 

 trouble taken to modify its influence in the manufacture of glass, an effectual process 

 of the kind would be a lucrative discovery. When sand containing oxide of iron is 

 mixed with a little charcoal and subjected at a red heat to the action of chlorine gas, 

 the whole of the iron is volatilised as chloride of iron, and the silica remains pure as 

 soon as the excess of charcoal is burnt off: this experiment seems to suggest the possi- 

 bility of purifying the glass-makers' sand, by the employment of waste muriatic 

 acid. Even at ordinary temperatures, the solution of oxide of iron by this means 



