DESERT REGIONS OF NORTH AMERICA. 17 
free of organic matter. On drying at r1o° to 120° C. no change in appearance 
occurred. This sample contained also minute amounts of calcium, sodium, fluoride 
sulphate, phosphate, titanite. 
Quantitative Analysis.—Preliminary Data. 
#, Sand dried in an air-bath at 30° to 35° C.: 
(a) On drying to constant weight in an air-bath at 50° to 60° C. the quantity 
of water eliminated was o.11 per cent. 
(6) On drying to constant weight in an air-bath at r1o° to 120° C. the 
quantity of water eliminated was o.19 per cent. 
B. Sand dried in an air-bath at 110° to 120° C.: 
(a) On ignition in platinum overa blowpipe the quantity of water eliminated 
was o.5 per cent. 
(0) On treatment for 3 hours with about 100 parts of hot acids, hot water 
or cold water per unit of substance the following data were obtained: 










| Solvent. ; Substance Residue. 
| dissolved. 
| | Pe ct Pe ck 
Meeeooe part 11Cl and three parts H,O................ | %.0 97.0 
mmo parts HNO, two parts H,0............2.6.+- | 2.6 97.4 
LE RE 2 Oe an a er | 0.5 99-5 
SE Oy CN el ae a | 0.6 99.4 
(c) In a percolation experiment similar to those on Sample I, only 0.4 per 
cent of the substance dissolved, 99.6 per cent remaining as residue. 
_ Percentage Composition. (Sand dried at 110° to 120°C.) 
i i: Average. | 
Peet, as bares 
Ee te er ee a eS SL ola PER we ees 85.9 86.1 86.0 
ie ae 
Fe,0, da ESRI Fe i eS rae ye ee a ae 5.3 O32 
RN ete his on iam in YO ok of tix ales 0.6 0.4 Gus 
feereracate, plus traces, Ca, Fl, SO,, etc............ - tee ee es. 
Silica and insoluble silicate, not less than............ ee Pisa 95.0 






General Conclusions.—This sand consists chiefly of silica and of insoluble sili- 
cates of iron and aluminum. The results of the extraction experiments, in which 
relatively large amounts of acid, alkali, and water affected it very little, show 
that the sand is one of the most insoluble and resistant varieties, and that it is not 
rapidly altered by weathering influences. 
