CHEMISTRY OF NATURAL WATERS. 175 



The Hudson carries daily about 4,000 tons of matter in solution, of 

 which more than 1,200 tons are calcium carbonate.^^ 



The Mississippi, as determined by Humphreys and Abbot,'** discharges 

 annually 21,300,000,000,000 cubic feet of water; from the analyses of 

 the water at New Orleans, by Dr. W. J. Jones,^^ we learn that the total 

 of solids carried annually by the river amounts to 112,832,171 tons; of 

 of which f)0, 158,161 tons are calcium carbonate. The amount of sediment 

 transported by the river annually, as reported Ijy Humphreys and Abbot, 

 amounts to 887,500,000,000 pounds or 443,750,000 tons. The amount of 

 solids, botli in solution and suspension, carried annually to the sea, as deter- 

 mined from the data indicated above, is approximately 556,600,000 tons. 



From the very incomplete observations on the discharge of the Hum- 

 boldt River that have been made, we will assume 500 cubic feet, or, for 

 convenience, 1,700 liters per second, as representing its average flow; each 

 liter contains 3615 2ram of solid matter in solution, which gives an an- 

 nual transportation of about 18,000 tons; of this amount somewhat less 

 than one-third, or approximately 5,000 tons, is calcium carbonate. In the 

 same general manner we have estimated that the Carson, Truckee, and 

 Walker rivers, collectively, transport annually about 10,000 tons of cal- 

 cium carbonate. Not to overestimate we will assume that all the streams 

 now entering the Lahontan basin carry annually 10,000 tons of calcium 

 carbonate in solution.' This estimate, although made on ver}^ imperfect 

 data so far as the measurements of the streams are concerned, is certainly 

 not too high, and enables one to understand whence the immense amount 

 of calcium carbonate deposited in the form of tufa from the waters of Lake 

 Lahontan was mainly derived. 



SPRING WATER. 



All the rain that falls does not find its way directly into the surface 

 drainage, but a large portion sinks into the earth, and in many cases has 

 a long underground passage before coming again to the light. During its 

 subterranean course it takes an additional quantity of foreign matter into 

 solution, and has its solvent power augmented by becoming more or less 

 thoroughly charged with certain substances, such as carbon dioxide, which 



"Report of the American Pnblie Health Associajiioii, Vol. I, pp. 542-543. 

 »* Report on the Mississippi River, p. 146. "^See Table of Analyses A. 



