DESERT REGIONS OF NORTH AMERICA. 15 
the sand as received. All of this material was regarded as extraneous matter, and 
only the main bulk of the sand was analyzed quantitatively. 
Qualitative Data.—The sand dissolved readily in water and in dilute acids, leav- 
ing only a slight residue of silicious matter. The black particles in the sand seemed 
to be entirely insoluble in these media. The aqueous solution was neutral to 
litmus. The hydrochloric acid solution was slightly yellowish in color, due doubt- 
less to the presence of iron. On diluting the hot concentrated sulphuric acid 
solution, crystals of calcium sulphate quickly separated. On igniting the sand it 
immediately blanched, and abundance of water was evolved, but the sand did not 
fuse, even in platinum, over.a blowpipe. Extraction of the ignited sand in water 
gave a solution slightly alkaline in reaction. Only a minute trace of carbonic acid 
gas could be produced from the sand on ignition, a fact showing that practically 
no organic matter is contained init. Such organic matter as was actually present 
in the few particles separated from the sand consists, as already stated, of the 
fragments of insects, excreta of animals, etc., and is too slight in quantity to have 
much significance as nutrient material for plants. 
On drying a sample of the sand in an air-bath at 100° C. it soon became trans- 
lucent and finally snow white. The grains retained their original shape. Water 
of crystallization was eliminated in abundance. The sand contains traces of 
sodium phosphate and chloride. The larger particles removed with the sieve con- 
tained a more decided quantity of chlorine, 0.7 to o.9 per cent. 
Quantitative Analysis —Preliminary Data. 
A. Sand dried in an air bath at 30° to 35° C.: 
(a) On drying a constant weight in an air-bath at 110° to 120° C. the quantity 
of water eliminated was 19.9 per cent. 
(6) On drying to constant weight in an air-bath at 50° to 60° C. the weight 
of the substance remained the same. 
(c) On continuous percolation at room temperature of small quantities of 
distilled water at a time over the sand, until about 100 parts water to 1 
of sand was used, 79.9 per cent of the sand was dissolved and only 20.1 
per cent of it remained as residue. The latter was still dissolving when 
the experiment was discontinued and further percolation would have 
reduced the amount of residue (see under Bb, (b) 4 below). 
(2) On continuous percolation, as above, with distilled water at 30° C. the 
dissolved matter amounted to 87.1 per cent and the residue to only 12.9 
per cent. Further percolation would have decreased the weight of the 
residue (see under B, (6) 3 below). 
B. Sand dried in an air-bath at 110° to 120° C.: 
(a) On ignition in a platinum crucible over a blowpipe the loss of weight was 
Dt Per cent, 
(6) On treatment for three hours with about 1 liter of hot acids, hot water, or 
cold water per gram of substance the following data were obtained: 



Solvent. Substance Residue. 
dissolved. 
Poe. Pd. 
I One part NCl and three parts H,O.. 97.4 a0 
2 Two parts HNO, and two parts H,O 97.8 2.2 
= AS UNET YS 2 ol BL eae Ge eter te ee Ge 94.3* Bay 
4 ONG 1 5 OO Ine es Fa een eee 96.4 2%. 6 





*Calcium sulphate is more soluble in cold than in hot water. 
