MR. JOHN film ASHLEY VII.-Analysis of Thames Water. By JOHNM.ASHLEY, ESQ. When we reflect upon the almost oountless uses to which the water of the River Thames is applied it creates some surprise that no accurate analysis of its waters should have appeared until the commencement of last year .* As no very certain knowledge of the composition af Thames water can be obtained by any other means than through the medium of a series of analyses of water taken at different places it is the intention of Dr. Hofmann to have these analyses conducted in the laboratories of the Royal College of Chemistry the present analysis formiug the second investigation of the series. The water analysed by Mr. Clark was obtained from Twickenham; that which I have used was taken from London Bridge on the 13th of October 1848 about half an hour after high water.It was a spring tide and the water was unusually muddy. The hour of the day was three o’clock P.M. The following data were observed Temperature of the water . . . 13O C = 55.4F. Temperature of the air . . . . 15O C = 59.0F. Specific gravity of the water. . . . l*OOOl. The qualitative analysis pointed out the presence of potash Bods lime magnesia alumina chlorine sulphuric acid silicic acid and organic matter. A very small amount of phosphoric acid was detected but it was in too minute quantity for estimation. After the evaporation of large amounts of water neither bromine iodiue nor manganese could be detected. The following experimental numbers were obtained by quantitative determinations.A. Determination of total amount of fixed constituents * Mr. Clark on Thames water Quarterly Journal of the Chemical Society vol. i. p. 155. ON THE ANALYSIS OF THAMES WATER. Amount of water employed. Amount obtained. Per-centage. I. 450.679 grm. 0.1859 grm. 0,041248 11. 564-5610 > 0.2%83 , 0*04(9438 Mean 0.040843 B. Determination of chlorine Amount of water employed. Amount of chloride Per-cent age of sodium obtained. of chlorine. I. 674.53 grm 0.1'737 grm. 0.006353 11. 419-66 , 0.1095 ,) 0.006478 Mean 0.006394 C. Determination of sulphuric acid Amount of water employed. Amount of sulphate Per-centage of of baryta obtained. sulphuric acid. I. 609-96grm. 0.0512 grm.0.002883 11. 703.181 , 0.0502 , 0 002452 Mean 0.002667 D. Determination of silicic acid Amount of water employed. Amount of silicic Per-centage of acid obtained. silicic acid. I. 1280*9110grm. 0.0227 grm. 0.000177 11. 1300*1560 ,> 0.0232 , 0.000178 ~ Mean 0*800177 E. Determination of lime and magnesia Amount of water employed. Amount of carbonate Per-centage of lime obtained. of lime. a. I. 1280*9110grm. 0.2651 grm. 0.011589 11. 1300.1560 , 0.2657 I 0.01 I444 Mean 0.011516 6. Determination of magnesia in filtrate from oxalate of lime Amount of water employed. Amount of pyro-phosphate Per-ceutage of magnesia obtained. of magnesia. I. 1280 9110 grm. 0.0527 grm. 0~000142 11. 1300.1560 , 0.0494 , 0.000140 Mean 0-000140 F.Determination of alkalies Amount of water employed. Amount of mixed chlorides obtained. 1. 2099.889grm. 0.3074 11. 2071°420 , 0.2936 $6 MR. JOHN Ma ASHLEY a. Determination of potash Amount of water employed. Per-centage of platinum Per-centage of and potassium obtained. potash. I. 2099.889 grm. 0.2494grm. 0*000228 11. 2071-4200 , 0*2040 , 0*000189 -Mean 0*000208 b. Determination of soda. Amount of water employed. Amount of chloride of Per-centage of sodium obtained. soda. I. 2099.889 grm. 0.2313 grm. 0.005881 11. 2071-4200, 0.2304 , 0-005918 ~-Mean *005899. 15309 grms. of the water were evaporated down to 801.47 grms. The precipitate which formed was separated and weighed 3.1115 grms. Determination of organic matter in the filtrate Amount of filtrate employed.Amount of organic Per-centage upon the matter burnt off. whole amount of water. I. 132980 grm. 0.0956 grm. 0.003763 TI. 136*2000, 0.0759 )) 0-00291 7 Mean 0.006656 Determination of organic matter in the precipitate iimount of precipitate Amount of organic Per-centage upon the employed. water burnt off. whole amount of water. I. 1,9350 grni.11. 0.4610 , 0.6407 grm.0.1471 , 0.006734 0.006479 ~- ~ 0-003340 Determination of carbonic acid At the time of collecting the water a syphon capable of containing 534 cubic centimetres of distilled water was filled twelve times and discharged into four bottles containing chloride of calcium and ammonia. The precipitate which had formed in all the bottles weighed 3.6067 grms.Amount of precipitate Amount of carbonic Amount calculated on employed. acid evolved. the whole precipitate. I. 0.4226grm. 0.1200 grm. 0.535662 11. 0.5144 , 0.1560 , 0.521 738 Mean 0.528700 Per-centage in the water 0.016495 ON THE ANALYSIS OF THAMES WATER From the analytical results the following composition of the water is deduced In 100 litres. In a gallon. (Grammes.) (Grains.) Sulphate of potash . . . . . -385 *2695 Sulphate of soda . . . . . . 4.436 3.1052 Chloride of sodium . . . . . 3.389 2.3723 Chloride of magnesium . . . . m114 $0798 Chloride of calcium* . . . . . 9.963 6,9741 Chloride of lime . . . 11.595 8-1165 177 01239 Silicic acid . . . . . . . Phosphoric acid .. . . . . . traces traces Alumina . . . . . . . traces traces Insoluble organic matter. . . . 6.656 4.6592 Soluble organic matter . . 3.340 2.3380 40.055 28.0385 Direct determination of fixed constituents 40.843 28.5901 Having deducted from the total amount of carbonic acid the amount required to combine with the lime the amount of free carbonic acid is 00005105 grm. corresponding to 27.1906 cubic centimetres in a litre or to 8.8076 cubic inches in an imperial gallon. The greatest difference between Mr. Clark’s analysis and my own consists in the variation in the amounts of soluble salts; the soluble salts found by hlr. Clark amount to only 6.3118 while I obtain as much as 18.287. A proportionate difference exists in the relative amounts of organic matter.My best thanks are due to Professor Hofmann for the many attentions and kindness that I have received from him during the above investigation. * On the principle of combining the strongest bases with the strongest acids in this analysis as well as in that of Mr. Clark chloride of calcium is enumerated along Mith sulphate of soda although we may assume that the constituents of these two salts are actually in solution in the form of sulphate of lime and chloride of sodium. MESS-R8. MAYER AKL) BRAZTER ON THE February 5 1849. Thos. Graham Esq. Vice-president in the Chair. A specimen of a phosphatic earth from the green sand formation of the south of England was presented by Mr. J. T. Herapath to the Society’s Musenm.This substance is now often substituted for bone-earth in the preparation of superphosphate of lime for agricultural purposes. It contains according to Mr. Herapath’s analysis traces. Organic matter . Silica with some silicate of alumina and 13.240 silicate of iron . .. Alkaline salt . ..traces. Carbonate of lime . 28.400 Y9 magnesia . traces. Sulphate of lime . 0.736 Phosphate of lime (tribasic) . 21-880 6C magnesia . traces. Perphosphate of iron . .. 211.760 Phosphate of alnmina . . . 7.032 Fluoride of calcium . traces. Water . 3.400 Lost . ... 0.552 100~000 The following paper was read