Water Analysis for Sanitary Purposes, Chemical and Biological

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Small, 1892 - Water - 88 pages
 

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Page 71 - ... the air we breathe, the water we drink, and the food we eat, as well as for eliminating the dangers to life and limb which now surround us.
Page 40 - In nesslerizing, five minutes are to be allowed for the full development of color ; after this, no change takes place for many hours. " Now throw out the contents of the retort, rinse it thoroughly, put in 200 cc of distilled water and 50 cc of the permanganate solution, distil down to about 100 cc , and nesslerize the last portion of 50 cc, to make sure of freedom from ammonia; add another portion of 500 cc of the water under examination, and proceed with the distillation and nesslerizing as with...
Page 39 - ... carbonate, the water is boiled down to about 100 (or 20) cc. and the last portion of 50 (or 10) cc. is nesslerized. If not free from ammonia, more water must be added and the boiling repeated till no appreciable amount of ammonia is contained in the last 50 (or 10) cc. of distillate. Then 500 (or 100) cc. of the water to be examined are added, and the distillation and nesslerizing are conducted as described by Mallet-Sharp (loc. cit., p. 280), the rate of boiling being so regulated that very...
Page 75 - Such a discussion would be out of place here, and the reader is referred to the volumes dealing with the other Johannine writings.
Page 37 - ... the permanganate-process above described — and as every adequate method for the determination of its organic matter in water must do — operates on the water itself, and not on the residue got on evaporation. The principle of the method is measurement of the nitrogenous organic matter in waters by the quantities of ammonia yielded by the destruction of the organic matter.
Page 32 - ... obtained in the distillation is calculated from the known strength of the dilute ammonia solution. In this process the sodium carbonate decomposes any ammonium salts in the water, and the ammonia so obtained, together with any free ammonia in the water, passes over and is collected in the distillate. Ammonia is one of the first products of the decomposition of animal matter and its presence in water in very large quantities must be...
Page 39 - ... detected by Nessler's reagent ; a yellow, yellowish-brown, or reddish-brown color or precipitate is obtained when free ammonia or ammonium salts are present. The color reaches its full depth in five minutes. Sodium Carbonate Solution. — Fifty gm. of pure sodium carbonate are intensely heated, dissolved in 250 cc of distilled water, and the solution boiled down to 200 cc Ammonium-Free Water. — If the distilled water of the laboratory gives a reaction with Nessler's reagent, it should be treated...
Page 56 - ... of lime and magnesia the water contains. Water that contains carbonic acid dissolves limestone, this is the reason that caves occur in limestone countries. Cold water dissolves more lime than hot water; if the water is boiled the carbonic acid is driven off. some lime is deposited, and it is called permanent hardness, the difference between the total hardness and the permanent hardness is the temporary hardness. The free anmv>nia.
Page 28 - Chlorides remain as evidences of past contamination after all other evidences have been obliterated, and resist in a marked degree the effects of filtration through the soil.
Page 82 - The work should be done in a room as free from dust as possible and with the windows and doors closed to avoid currents of air.

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