Note 3 — Chapter I · ON WATER AND ITS COMPOUNDS

Spring water is formed from rain water percolating through the soil. Naturally a part of the rain water is evaporated directly from the surface of the earth and from the vegetation on it. It has been shown that out of 100 parts of water falling on the earth only 36 parts flow to the ocean; the remaining 64 are evaporated, or percolate far underground. After flowing underground along some impervious strata, water comes out at the surface in many places as springs, whose temperature is determined by the depth from which the water has flowed. Springs penetrating to a great depth may become considerably heated, and this is why hot mineral springs, with a temperature of up to 30° and higher, are often met with. When a spring water contains substances which endow it with a peculiar taste, and especially if these substances are such as are only found in minute quantities in river and other flowing waters, then the spring water is termed a mineral water. Many such waters are employed for medicinal purposes. Mineral waters are classed according to their composition into—(a) saline waters, which often contain a large amount of common salt; (b) alkaline waters, which contain sodium carbonate; (c) bitter waters, which contain magnesia; (d) chalybeate waters, which hold iron carbonate in solution; (e) aërated waters, which are rich in carbonic anhydride; (f) sulphuretted waters, which contain hydrogen sulphide. Sulphuretted waters may be recognised by their smell of rotten eggs, and by their giving a black precipitate with lead salts, and also by their tarnishing silver objects. Aërated waters, which contain an excess of carbonic anhydride, effervesce in the air, have a sharp taste, and redden litmus paper. Saline waters leave a large residue of soluble solid matter on evaporation, and have a salt taste. Chalybeate waters have an inky taste, and are coloured black by an infusion of galls; on being exposed to the air they usually give a brown precipitate. Generally, the character of mineral waters is mixed. In the table below the analyses are given of certain mineral springs which are valued for their medicinal properties. The quantity of the substances is expressed in millionths by weight.

Calcium salts Sodium chloride Sodium sulphate Sodium carbonate Potassium iodide and bromide Other potassium salts Iron carbonate Magnesium salts Silica Carbonic anhydride Sulphuretted hydrogen Total solid contents

I. 1,928 — 152 — — 24 — 448 152 1,300 80 2,609

II. 816 386 1,239 26 — 43 9 257 46 1,485 — 2,812

III. 1,085 1,430 1,105 — 4 90 — 187 65 1,326 11 3,950

IV. 343 3,783 16 3,431 — 14 — 251 112 2,883 — 7,950

V. 3,406 15,049 — — 2 — 17 1,587 229 — 76 20,290

VI. 352 3,145 — 95 35 50 1 260 11 20 — 3,970

VII. 308 1,036 2,583 1,261 — — 4 178 75 — — 5,451

VIII. 1,726 9,480 — — 40 120 26 208 40 — — 11,790

IX. 551 2,040 1,150 999 — 1 30 209 50 2,749 — 4,070

X. 285 558 279 3,813 — — 7 45 45 2,268 — 5,031

XI. 340 910 Iron and aluminium sulphates: 1,020 940 190 2,550 Sulphuric and hydrochloric acids

1,660 330

I. Sergieffsky, a sulphur water, Gov. of Samara (temp. 8° C.), analysis by Clause. II. Geléznovodskya water source No. 10, near Patigorsk, Caucasus (temp. 22·5°), analysis by Fritzsche. III. Aleksandroffsky, alkaline-sulphur source, Patigorsk (temp. 46·5°), average of analyses by Herman, Zinin and Fritzsche. IV. Bougountouksky, alkaline source, No. 17, Essentoukah, Caucasus (temp. 21·6°), analysis by Fritzsche. V. Saline water, Staro-Russi, Gov. of Novgorod, analysis by Nelubin. VI. Water from artesian well at the factory of state papers, St. Petersburg, analysis by Struve. VII. Sprüdel, Carlsbad (temp. 83·7°), analysis by Berzelius. VIII. Kreuznach spring (Elisenquelle), Prussia (temp. 8·8°), analysis by Bauer. IX. Eau de Seltz, Nassau, analysis by Henry. X. Vichy water, France, analysis by Berthier and Puvy. XI. Paramo de Ruiz, New Granada, analysis by Levy; it is distinguished by the amount of free acids.