28 



The National Geographic Magazine 



to leave no question of these facts. Pre- 

 vious researches have not taken sufficient 

 account of the locality of the small pans 

 in deriving their formulas, and they have 

 been discordant as a consequence. 



The preliminary discussions of the 

 data, made since our return to Wash- 

 ington, show that we must depart from 

 the common Dalton Law in at least four 

 important particulars, and we shall pro- 

 ceed to test the new formula as fully as 

 possible within the next few years. 



It is our purpose to erect two or three 

 towers at the Salton Sea, one high tower 

 on a small island about four miles from 

 the southern edge of the sea, to get some 

 idea of the behavior of the great vapor 

 blanket lying over that large water area. 

 We must know its depth and how it acts 

 over a large body of water, as compared 

 with the small Reno reservoir. There 

 will be two smaller towers in the sea, one 

 about one mile from the Salt Creek tres- 

 tle and projecting 20 feet from the sur- 

 face, and another in 50 feet of water and 

 flush with the surface. As the waters 

 recede under evaporation, in a few years 

 these sea towers will gradually become 

 land towers, and this will enable us to 

 study the working of the blanket from 

 the middle of the sea into the country — 



that is, for large and for small lakes — in 

 the course of a few years. It is purposed 

 to invent, if possible, suitable apparatus 

 for self-registering the evaporation and 

 for recording the vapor contents of the 

 atmosphere. 



There are, however, numerous and 

 serious difficulties to be overcome in the 

 carrying on the work at the Salton Sea, 

 and not the least is the hardship of en- 

 during the high temperatures of the sum- 

 mer as well as the loneliness of the iso- 

 lated life that must be experienced by the 

 observers. The officials of the Southern 

 Pacific Railroad — Mr R. H. Ingram, the 

 general superintendent of the Southern 

 California division, and Mr A. D'Heur, 

 the chief engineer — have courteously 

 agreed to cooperate with the U. S. 

 Weather Bureau in the construction and 

 maintenance of the piers, towers, and 

 houses needed for the investigations. 



I was assisted at Reno, Nevada, by Mr 

 H. L. Heiskell of Washington, D. C, Mr 

 Geren, Mr Robeson of Reno, Professors 

 Minor and Church of the University, by 

 Messrs Pearson, Steffin, Beebe, Potthoff, 

 students, and by many citizens of the city 

 of Reno, to all of whom the Weather 

 Bureau is greatly indebted. 



METHODS OF OBTAINING SALT IN COSTA 



RICA 



THE following series of illustra- 

 tions, showing the methods of 

 obtaining salt on the Pacific 

 coast of Costa Rica, were taken by Pro- 

 fessor Y. Fid Tristan of San Jose. Pro- 

 fessor Tristan is a member of the Na- 

 tional Geographic Society who lives in 

 Central America, and sends the pictures 

 to its Magazine that all the members of 

 the Society may see this quaint method of 

 getting salt. 



There are only a few miles of railway 



in Costa Rica. Transportation is there- 

 fore expensive, but labor is cheap. While 

 the salt obtained in this primitive manner 

 is coarse, it answers most of the require- 

 ments of the people. Costa Rica is one 

 of the most interesting sections of the 

 Americas. The proportion of its white 

 population is large for a Latin American 

 country. Public instruction is free and 

 compulsory and the Costa Ricans are 

 among the most cultured of the American 

 peoples. 



