682 POPULAR SCIENCE MONTHLY. 



several hours before using, so that the sulphur may be volatilized and 

 the temperature reduced. 



Florida is a well watered country. Lakes, streams and springs are 

 extremely numerous. The underlying limestone is full of caverns 

 containing water. Every one knows about the Silver Spring in Marion 

 County. It starts as a full-grown river from a spring 25 to 30 feet 

 deep, perfectly clear, with an outlet GO feet wide, 10 to 14 feet deep. 

 It is the Oclawaha Eiver, navigable for steamers from its very source. 

 The water is probably the rainfall of the region filtering through miles 

 of sand, with a temperature of 72° and perceptibly calcareous to the 

 taste. 



The water in the lakes is purer than that from the springs, probably 

 because on exposure the compounds break up, and the gases, sulphur and 

 hydrogen, carbonic acid, oxygen and nitrogen (common air) are elimi- 

 nated. The Everglades and Lake Okeechobee illustrate this fact. The 

 steamers plying down the Kissimmee Eiver, across Okeechobee and down 

 the Caloosahatchee Eiver to Fort Myers obtain their drinking-water 

 from far out in the lake, because nowhere else can it be found so palat- 

 able, or so well fitted for use in the boilers of the steamers. 



The source of the sulphuretted hydrogen must be the various sul- 

 phates decomposed by the action upon them of organic matter. The 

 mineral compounds arise naturally from the solubility of the various 

 salts, either from the original strata or from their dissemination 

 through the soil. 



Fresh-ivatcr Springs in the Ocean. 



Many of these underground streams proved to exist by the artesian 

 bore-holes are of great volume, and hence must pass to some distance 

 under the ocean. This fact is further corroborated by the small degree 

 of salinity even in the deeper wells. Statements made by residents 

 claim the existence of fresh-water springs miles away from the land 

 opposite St. Augustine, Matanzas and Ormond. The first of these 

 is also mentioned by T. C. Mendenhall, formerly superintendent of the 

 United States Coast Survey, in a letter to J. W. Gregory, in charge of 

 Artesian Well Investigations, Department of Agriculture. 



Mr. M. L. Fuller furnishes me with the following additional 

 localities. Dr. Mendenhall mentions the reported occurrence of fresh- 

 water springs off the mouth of the Mississippi Eiver. In ' The Island 

 of Cuba,' by Lieutenant A. S. Eowan and M. M. Eamsey (Henry Holt 

 & Co., 1896), page 18, it is stated that the water is often forced by 

 hydrostatic pressure to the surface far out at sea. Elisee Eeclus 

 remarked that 'in the Jardines (east of the Isle of Pinos), so named 

 from the verdure-clad islets strewn like gardens amid the blue waters, 

 springs of fresh water bubble up from the deep, flowing probably in 

 subterranean galleries from the mainland.' 



Mr. Fuller also adds the following quotation from a paper by 



