MR. JOHN MITCHEL ANALYSIS OF TKI III.-Analysis of the Water supplied by the Humpstead Water-works Company. By JOHNMITCHEL, ESQ. The deep well water from Messrs. Conibe and Delafield’s Brewery has been analysed by Professor Graham and the water of the Artesian Wells at Trafalgar Square by Messrs. Abel and Rowney as well as that of the ‘I’hames by Mr. Clark but I am not aware that the waters supplied by the London Water Companies have yet been subjected to analysis. It was thought that such a series of analyses moulcl be an useful addition to thosc already cited not only in a scientific but also iri a sanatory point of view. The present communication the first of the series has reference to an examination of the water supplied by the Hampstead Water-works Company.The water was not taken direct from the works but analyzed as supplied to the house; the chief object being to ascertain whether the water in question possessed any power of taking up lead or zinc as I had been informed on the authority of a plumber in the neiphbourhood that such %as the case WATER SUPPLIED BY THE HAMIPSTEAD WATER-WORKS 33 with reference to the former metal I have found that as far as the water analyzed was concerned no perceptiblc action was exerted and I am the more iiicluced to believe this correct from the circumstance that several leaden cisterns have been for a great number of years continually subjected to its influeiicc and do not appear affected in the slightest degree. This may be in some measure explained by the comparatively large quantity of soluble sulphates contained in the water as it Bas been shewn by Dr.Christison that water containing even a small amount of sulphates is comparatively without action on metallic lead. The water is pumped continuously from a plain bore-hole at the Works in Pond Street Hampstead and is obtained partly from the sand and partly from the chalk. The specific gravity of the water at 58O F. is 1000.65 distilled water being 1000. Qualitative analysis exhibitccl the presence of magnesia lime potash and soda with sulphurie silicic and carbonic acids chlorine organic matter and a trace of phosphoric acid. A. Determination of the total amount of fixed constituents. Amount of n ater. Fixed residnc. Per-centage.I. 4000 grs. 2.284grs. 0.0571 11. 3500 , 2.002 ,) 0.0575 Mean 0.0573 B. Determination of sulphuric acid Amount of water. Sidphate of bar) ta. Per-centage of Sulphuric acid. I. 4000 grs. 1.136 grs. 0-0097524 Ir. 3581 , 133.1 , 0.009 7504 Mean 0.0097514 C. Determination of chlorine. Amount of water. Amount of chloride Chlorine per cent. of silver. I. 3524 grs. 2216 grs. 0.01555 11. 4120 ,> 2-590 , 0.01567 Mean 0.01566 D. Determination of the silicic acid. Amount of water. Amount of silicic acid. Silicic acid per cent. grs. 0.00040685 I. 8750 grs. 0-03.2 11. 10000 , 0.041 , 0~00041000 Mean 0.00040842 D MR. JOHN MITCHEL ANALYSIS OF THE E. a. Determination of the total amount of lime. Amonnt of water.Amount of carbonate Lime per cent. of lime. I. 7850 grs. 0.801 grs. 0.005717 ;11. 10000 , 1.020 0.005615 17lean 0.005666 A given quantity of water was boiled for half an hour the flask being so arranged that no evaporation could take place. The pre- cipitate formed was separated by filtration aiid the amount of lime in the precipitate and filtrate determined in the usual manner. 6. Estimation of lime in the precipitate. Amount of water. Amount of carbonate Per-centage of lime in the of lime. water as carbonate. 8000 grs. 0.438 grs. 0.003056 c. Determination of lime in filtrate. Amount of water. Amount of carbonate Per-centage of lime in the of lime. water as soluble salts. 8000 grs. 0.371 grs. 0.0025997 F. Determination of magnesia.Amount of water. Pyro-phosphate of Per-centage of magnesia. magnesia. 7850 grs. 0.505 grs. 0.002355 10000 , 0.644 , 0.002357 Mean 0,002356 G. Determination of the alkalies. Amount of water. Amount of chlorides of potassiurn and sodium. 10000 grs. 3475 grs. 8000 , 2.782 , a. Estimation of potash. Amount of water. Potassio-chloride of Per-centage of potash. platinum. 10000 grs. 1.313 grs. 0-0025335 8000 , 1.050 , 0.0025326 ~ Mean 0.0025330 6. Estimation of soda. Amount of water. Chloride of sodium. Per-centage of sods. 10000 grs. 3.074 grs. 0.0016193 2.450 , 0.0016232 >J MeaH 0.00162125 WATER SUPPLIED BY THE HAMPBCEAD WATER-WORKS. 35 H. Determination of carbonic acid. This was determined in the usual manner by the addition of a mixture of chloride of calcium and ammonia to a known weight of water.21000 grs. of water thus treated gave 8.21 grs. of precipitate which by the ordinary process yielded 1456 grs. of carbonic acid = 0.006938per cent. of that body in the water. In order to determine the phosphoric crenic and apocrenic acids and extractive matter 100lbs. of the water were evaporated to 2 lbs. giving 72 grs. of precipitate the filtrate and washings weighing 25000 grs. I. Determination of phosphoric acid in combination with lime. Amount of precipitate. Pyro-phosphate of Per-centage of magnesia. phosphoric acid. 17 grs. 1.016 grs. 0.000392 K. Determination of organic matter. a. Apocrenic acid. Amount of precipitate.Copper-salt obtained Per-centage of apocrenic acid. 22.2grs. 0.320grs. 0.00012005 b. Crenic acid. Amount of precipitate. Copper-salt obtained. Per-centage of crenic acid. 22.2 grs. 1.986 grs. 0.000237 c. Extractive matter. Amount of filtrate. Extractive matter. Per-centage of extractive matter. 10000 grs. 6-88grs. 0.0002457. According to the above results the water contains per imperid gallon in grains Carbonate of lime . 3.83250 Carbonate of magnesia 3.40830 Phosphate of lime . . 027672 Sulphate of lime . 442018 Sulphate of potash . . 3.27812 Sulphate of soda . 4.81130 Chloride of sodium . . 17*75814 Silica acid . . *28589 Crenic acid . . 016590 Apocrenic acid . 008403 Extractive matter . . 1.71990 Oxides of iron and manganese. * traces 4D04110 D2 DR HOPMANN ON THE ANILIDES. The ainouut of fisccl rcsicluc obtained by direct experiment was 49-11 grs. pcr gallon. The amount of pure carbonic acid in the water is 4.39 cubic inches in the imperial gallon.