October 27, 1922] 



SCIENCE 



471 



ing party, for it proved too heavy for the 

 climb in the new soft snow below the Chang 

 La, and he had been compelled to turn back 

 from the rear of the party only a few minutes 

 before the train of porters was carried away 

 by the avalanche. 



Captain Noel in his letters mentions many 

 difl&eulties in photogi'aphy at extreme alti- 

 tudes : the most 'curious is the effect of the dry 

 Tibetan climate on the cinematograph film, 

 which cracks and sparkles with electric sparks 

 when pulled through the band, so that it is 

 necessary to ' work with a wet hand when 

 threading the film on the developing frames. 

 Happily this eifect was anticipated, and the 

 makers of the Newman-Sinclair camera suc- 

 ceeded in making the film run through the gate 

 without friction, and provided open-mouthed 

 film boxes, so that damage from electrical 

 markings is reduced to a minimum. 



The official photographs which have come 

 home from the expedition up to the time of 

 writing comprise about 200 quarter-plate nega- 

 tives on glass, a certain number of large pan- 

 orama films, and two small V.P.K. fikns. These 

 are supplemented by good series of pictures 

 taken by Dr. Longstaff and Captain Pinch, 

 which have been placed at the disposal of the 

 committee. A selection of enlargements is 

 shown in the Photograph Room of the society, 

 but the record must be very incomplete until 

 the arrival of Captain Noel in October with all 

 the larger plates. Enlargements from these 

 will be shown as soon as possible, and the 

 Mount Everest Committee will probably ar- 

 range for a public exhibition of the pictures 

 in the Alpine Club Hall after Christmas, as 

 was done last January. 



SCIENTIFIC EVENTS 

 NITRATES IN SOUTHEASTERN CALIFORNIA 



Nitrogen is needed in large quantities for 

 use in fertilizers, in explosives required in 

 engineering and mining, and in munitions made 

 for national defense in war. During the war 

 the demand for nitrates became so urgent that 

 every known source of them in the United 

 States was ransacked to find enough to supply 

 our ever-increasing needs. The world's store- 



house for nitrates is Chile, but the growing 

 menace of the submarine made it imperative 

 to divert to other uses the shipping then en- 

 gaged in the Chile nitrate trade. 



Small quantites of nitrates are found in 

 almost every region where the rainfall is very 

 small. The most promising deposits in the 

 United States were those in the Amargosa re- 

 gion, in southeastern California. Before the 

 war some of these deposits had been examined 

 several times, chiefiy by private companies that 

 sought to obtain capital for their exploitation, 

 but the reports made were so conflicting that 

 the United States G-eological Survey, Depart- 

 ment of the Interior, decided to make a careful 

 study of all the deposits in that region. 



The nitrate-bearing material, or "caliche," as 

 it is called in California, resembles in character 

 and mode of occurrence the well-known caliche 

 found in Chile, but it is much poorer and 

 thinner. It forms a layer a few inches thick 

 that lies less than a foot below the surface, at 

 the plane of contact ibetween the unaltered 

 bedrock, which there consists chiefly of beds of 

 Tertiary clay shale and the overlying clay soil. 

 A white powdery layer, composed chiefly of 

 sulphate of sodium and calcium, nearly every- 

 where lies between the caliche and the clay 

 soil. The caliche cuts across successive tilted 

 beds of the underlying clay shale and is thus 

 clearly independent of the geologic structure. 



In the examination made by the Geological 

 Survey maps and cross sections were made at 

 many places. Scores of trenches and hundreds 

 of pits were dug down to or into the bedrock, 

 and the soil, caliche and bedrock were then 

 systematically sampled. Many hundred quali- 

 tative tests and nearly a thousand quantitative 

 analyses of the caliche were made. The com- 

 mercial development of the deposits, though 

 they are the most promising in the country, 

 was found to be impracticable, but the results 

 of the investigation should set at rest any 

 uncertainties as to the nature or quantity of 

 the nitrates in the areas examined and should 

 serve as a guide in the exploration of other 

 supposedly nitrate-bearing regions. 



An account of this investigation is given in 

 the Geological Survey's Bulletin 724, on 

 "Nitrate Deposits in the Amargosa Region, 



