

.SAND. 



SANDARAC. 



naiy should thereafter be admitted or allowed iu any case- 



[ABJURATION' OF THE RKALM ; ASYLUM.] 



(Reeves's llininry of the Enijliili Lam; Comyu's Dijeit, tit. ' Abju- 

 n :' 4 BL, Com.) 



s \ N D. The fine angular materials derived from the disintegration 

 of rocks, and deposited according to the gravity of the various particles 

 under the action of running water, are technically known by the 

 generic term " tandt" They are, for the purposes of classification, 

 subdivided into river sand, sea sand, and pit sand; volcanic, cal- 

 careous, argillaceous, or silicious sand ; red, yellow, or white sand ; 

 according to their manner of occurrence, their qualities, or their colour. 

 In the arts they are used for many purposes, but as their applications 

 in the manufacture of mortar, of plastic building materials, and of glass, 

 are, perhaps, of the greatest practical importance, attention will be 

 principally called to these applications ; but before doing so it may be 

 of interest to observe that the sea-sands on some parts of the shores of 

 the Atlantic are largely used in agriculture, on account of the large 

 quantity of calcareous and nitrogenous matters they contain. This 

 application of sand, uf the description known locally by the name of 

 " tangue," prevails in the departments of the Calvados, Manche, Cotes 

 du Xord, ic., iu France, to a very great extent, and it is found to be 

 very beneficial. 



For mortar making, sands may be selected according to the pro- 

 perties of the lime in connection with which they arc employed, as 

 under some circumstances they play a very important part in the 

 chemistry of the hardening of the mortars. As was said under MORTAK, 

 the value of that class of materials depends upon the rapidity and the 

 energy with which the double silicate of lime and alumina is formed ; 

 and it therefore follows that the .-*ainU which contain the various ingre- 

 dients iu a state susceptible of entering into combination with the 

 lime, are those which are of the greatest value. The sands derived 

 from the destruction of the purely silicious rocks are for the most part 

 totally inert for the purposes under consideration, because the silica 

 they contain is in a permanent crystalline form ; but the sands derived 

 from the destruction of gueixs, grauwaokc, felspathic granites, and 

 other rocks, in which the silicious acid doc* not exist in a stable com- 

 pound, are easily acted upon by pure caustic lime. Thus it is found 

 that in the north of Spain, ami iu tin- granitic district of the north of 

 France, the decomposition of the felspathic granites of those districts has 

 produced a sand in which the silicate of lime of the felspar exists in a 

 state able to combine with the pure hydrate of lime, there obtained by 

 slaking the caustic lime derived from the more pure crystalline lime- 

 stones. The volcanic sands, known technically by the names of 

 pozzuolanrn and traa, act even more energetically than the sands from 

 the felspathic rocks ; and when mixed with the pure hydrate of lime 

 in proper proportions, they even communicate to it properties nearly 

 -null ir to those of natural cements. On the other hand, sands con- 

 taining plastic clay in its natural state are positively injurious ; not 

 only because the clay doe* not exist in them in a state able to form 

 any stable compound with the lime, but also because it prevents the 

 latter from performing one of its most useful functions in a mortar ; 

 namely, that of presenting a nucleus around which crystallisation could 

 take place in the lime'itself. At the present day it is believed that 

 with the energetic cements a sharp, angular, crystalline sand, one whose 

 chi-iiiical properties would be totally inert, is the beet adapted for 

 mortar making ; with hydraulic limes the sands ought to possess the 

 faculty of slowly forming new compounds with the hydrate* of lime ; 

 and with rich limes, especially if they are required to be used in sea- 

 water, sands exercising an energetic action on the hydrates must 

 exclusively be used. 



These remarks point to a rough practical subclasgification of sands, 

 into the classes of the inert, il'ujMij entrt/etic, and dtci'lnlly ("/>/;' 

 and.* ; and Vicnt, who was the first to call attention to this description 

 of action, states that when winds are treated by acids and by lime- 

 water they may easily bo di.-ttinpii.ihi.il from one another. Thus the 

 inert sands resist the action of acids, and are totally without action upon 

 even boiling linn-water. The slightly energetic sands yield in a trifling 

 ; > the acid.-<, and take up a small proportion of lime from the lin 

 The decidedly energetic lands are powerfully affected by acids, 

 and they take up a large proportion of the lime presented to them in 

 solution. Curt- nin-t. however, be taken in the experiments on the 

 nature of this class of materials to allow for the action of the acids 

 upon the lime present in the sand ; for all purposes connected with the 

 formation of the insoluble silicate of lime and alumina by the reciprocal 

 a< -lions of the caustic lime and the sand, the calcareous matters of the 

 latter will remain practically inert. 



Wht-n .;on-id<T.;d with reference to their source* of supply, it may 

 generally speaking be regarded that sea sands are purer and better 

 for mortar making than any other ; provided always that the 

 efflorescence of the muriate of soda they contain should not be likely 

 to affect injuriously the character of the work. This would be the 

 caw with all internal decorations ; and sea sand must therefore 

 be carefully excluded from all ornamental structures. River sand is 

 alao very likely to contain the muriate of soda when obtained from the 

 tidal portions of a stream, and in addition to this inconvenience there 

 i* almost a certainty that the river sand \vill contain a large proportion 

 of nitrogenous element*, which would in a building give rise to the 

 formation and efflorescence of the nitrate of lime, which in its turn 



ARTS A!l> SCI. DIV. VOL. VII. 



would be fatal to any coloured decorations or paintings exposed to its 

 effects. Pit sand is in fact the most generally fitted for building pur- 

 poses ; but care must be taken with it to secure that it should be free 

 from argillaceous ingredients, and only that sand should be used whose 

 grains are sharp and angular. The specific gravity of a sand is a prim A 

 facie evidence of its goodness. 



In brick and tile making, and iu some processes of the higher 

 ceramic arts, sand is occasionally used when the clay is, to use the 

 workman's phrase, " too rich ; " that is to say, when it is exposed to 

 run together in the kiln iu an irregular manner, in consequence of an 

 excess in the proportion of alumina the clay may contain. A clay is 

 considered, iu fact, to be rick when the proportions of silica and 

 alumina are respectively 60 and iO per cent. ; it is considered to be 

 jiu'ji- when those proportions are 80 and 20 per cent. ; and according to 

 the usage intended to be made of the clay a greater or less proportion 

 of pure silicious sand must be added to the richer varieties. See 

 Brogniart, ' Traite" des Arts Ceramiques.' 



The very pure and perfectly white silicious sands which are found 

 ill Norfolk and in Alum Bay, Isle of Wight, used formerly to be raised 

 in large quantities for glass making. The supply has been nearly 

 exhausted ; and latterly some of the best sands for this important 

 branch of manufacture have been imported, in ballast, from Australia ; 

 rich ferruginous sands for steel making are also imported from New 

 Zealand. 



It may be desirable to add, that the fine sands charged with organic 

 matters to bo found in the embouchures of rivers, or in some bays 

 on the sea-shore, are technically known by the name of silt, and that 

 they arc very rarely of any commercial value. Pit sands, or large 

 deposits of sand in the interior, are occasionally found to be so charged 

 with water as to remain constantly in motion, and are then called 

 wnls. Under these conditions they form one of the most 

 dangerous class of foundations, for if an escape should be found for 

 the waters they may contain, the sands would in all probability be 

 removed by them, and the foundations would be exposed to lateral 

 displacement. The precautions to be taken in such cases are, if 

 possible, to intercept the supply of water to the sand; if that 

 cannot be effected, to keep it constantly charged ; and, under either 

 of those conditions, to isolate the immediate surface of the foundations 

 in such a manner as to allow any movements which may be produced 

 to take place vertically. Dry sand has, in its dry state, been often used 

 in foundations instead of concrete ; and if it be prevented from spread- 

 ing laterally, that material is practically incompressible. It is also 

 used for tamping round the charges of mines. 



SAND ; SANDPAPER. Many varieties of sand are used for 

 manufacturing purposes. Stone-masons often use the scrapings of 

 granite roads to aid the action of their stone-saws. Engineers fre- 

 quently employ grindstone dust. River-sand and pit-sand are gene- 

 rally sharper or more angular than sea-sand ; this difference leads to 

 the selection of each for certain purposes. Kent sand is largely used 

 at Sheffield. l-in^ lim- and sharp ; it is found an economical substitute 

 for polishing powder for steel good*, ^mid-paper consists of sand 

 sprinkled over and cemented upon sheets of paper ; it differs from 

 emery-paper [EMKKY] and glass-paper rather in the kind of substance 

 used than in the nature of the action. 



SAND VOLTAIC BATTERY. A form of battery sometimes used 

 in connection with the Electric TELEURAPH, consisting of a number of 

 pairs of copper and zinc, with the cells filled with sand, which is kept 

 moist by means of dilute sulphuric acid. This battery will remain 

 active fur a considerable time, and its activity can be renewed at 

 pleasure merely by wetting the sand. 



BANDAL-WOOD, RKD, or K.il Samplers Wood of Commerce. 

 [I'TKHor.viiiM-s, in XAT. lli.vr. DIV. | 



SANDARAC is a secretion from the Cnllilris </ii<ii/r!ru/i'is, a tree of 

 enormous size, native of Marocco, and there called Arar. It exudes 

 spontaneously from the bark, and concretes on the surface. It occurs 

 in small, irregular, but rather elongated, seldom perfectly round tears, 

 or in masses run together, of a light yellow colour, sometimes verging 

 to brownish, of a dull hue externally, gfin-rully rov.-i-c.l with powder, 

 but when this i.< i-i-moved, semitransparent. It breaks easily with a 

 conchoidal fracture and vitreous lustre/ The powder is white, and 

 forms the substance called pouiire. By chewing, it forms a fine powder, 

 which does not agglutinate, and lias a faint balsamic taste. At ordinary 

 temperatures it is without odour, but by the application of heat it 

 easily melts and diffuses a strong though not unpleasant odour, resem- 

 bling that of juniper or mastic. It is easily ignited. It is soluble to 

 the extent of four-fifths iu cold alcohol ; and the insoluble residuum is 

 easily soluble in ether, or, slowly and with difficulty, in boiling turpen- 

 tine. The portion insoluble in alcohol is termed N'liiiliiracin. 



Sandarac is used for the preparation of varnishes, also occasionally 

 for incense or pastiles, plasters, and ointments. The powder is rubbed 

 on parchment to render it fit to be written on. S.mdarac is sometimes 

 used to adulterate mastic ; and on the other hand, a resin obtained 

 from the J" "tmunis, and another from J, O^nccdrug, are 



employed as a substitute for the genuine sandarac. In Sweden, lump.! 

 of resin which are found under ants' nests below the juniper bushes 

 are called saudarac. The resin of the Pinus damma.ru, is called French 

 sandarac iu commerce. Sandarac is incorrectly called a gum ; it 

 partakes more of the nature of a resin. 



