ON TWO ANALYSES OF WATER DRAWN FI1036 THE SANE WELL. By A. DUPBE’, Ph.D. F.R.S. Read before the Society of Public Analysts on 1st Hay, 1878. A SHORT time since I received from Mr. R. Field, the well-known sanitary engineer, two aamples of water for examination. Both samples mere drawn from wells situated close to the dwelling house which they supplied, at front and back respectively. Finding one of these waters to be very decidedly the best, I recommended that this only should be used for all culinary and other purposes.In reply to my report I was informed that the water I had recommended could not be used owing t o the bad smell it evolved on boiling. or in the boiler, and that probably some mistake had been made in marking the samples. Accordingly 1 had a second sample of water from the well I had recommended forwarded to me, of which I need here only say that it proved conclusiyely that no mistake had been made the first time.When, however, I took about two pints of this water and raised it nearly to boiling it evolved, more particularly on shaking, a very offensive smell. Testing the smell of the water in my usual way, i e . , by heating about five ounces of it to a temperature of looQ I?., shaking up briskly in a wide mouthed bottle, and at once applying the nose, I still failed to detect any smell. No trace of sulphurctted hydrogen was present.Here then was a water clearly unfit for domestic use, which analysis had never- thelees, as the figures given below will show, pronounced pure. This result puzzled Mr.Field not a little, the more so as he considered the whole surroundings of the well as exceedingly unfavourable. The case was also extremely unsatisfactory to myself, as266 THE ANALYST. in the face of my analysis, confirmed by the second sample, I could not do otherwise than pronounce the water to be pure, barring the offensive smell evolved on boiling. A few days later Mr.Pield, who had meanwhile again visited and carefully inspected the place, an inspection which confirmed all his previous misgivings, informed me t4hat the house to which the well in question belonged had not been inhabited for some months past, and that during such time little or no water had been drawn from the well. I therefore requested to be furnished with a third sample from the same well, which was, however, to be taken only after the well had been as far as possible pumped dry and then been allowed t o refill itself.The analysis of this water, also given below, shows a considerable degree of pollution, and indeed proves the water to be unfit for domestic use, The offensive smell evolved on boiling was however, if anything, rather less marked in this than in the previous sample.How then is this striking difference in the character of the water drawn from the same well t o be accounted for? It is, of course, well known that even very foul water left to itself, in tanks or barrels, becomes purified and fit for drinking in process of time, and I suppose that something similar had taken place in this case, The water, left undisturbed in the well for months, had undergone a gradual process of purification, aided perhaps by vegetation or by dilution with rain-water.Similar cases have, I believe, been observed by others, but I venture nevertheless to bring it before you as it emphasises far more strongly than any case I am acquainted with the absolute necessity of having a considerable quantity of water drawn from a well before the sample is taken for analysis. Had the water in the present case not possessed thi8, 80 to speak, accidental and minor character of smell, the well would have been considered good in spite of its surroundings and the misgivings of the engineer, and serious mischief might have resulted.I n conclusion, I may state that the well in question has a depth of seventeen feet with about eight feet of water.The upper part, down to within about half a foot of the water level, passes through vegetable mould, sand and gravel, the remainder is in the chalk. The chalk in the neighbourhood of the well is penetrated by innumerable rootlets, and when broken up gives out a very offensive smell. Round these rootlets, many of which are decaying, the chalk is colwred black by sulphide of iron.A cesspool, now about t o be filled in, is situated at a distance of about seven yards from the well, and a brick drain runs at about the same distance past the well, which latter I need scarcely add will also be filled up. Appearance . . . . . . . . . clear . . . . . . Colour . . . . . . . . . . . . pale greenish . . . . . . Taste .. . . . . . . . . . . tasteless .., * a , Smell . . . . . . . . . . . . inodorous" .I. .** Deposit . . . . . . . . . . . . none . . . . . . Nitrous Acid . . . . . . . . . none . . . . . . Phosphoric Acid . . . . . . very strong trace . . . . . . Hardness before boiling, ... 27'0 degrees (Clark) . . . . . . .. after . . . . . . . . 9.5 ,, ,? . . . . . . Oxygen absorbed from permanganate 0*014 . . . . . . 0.035 Total dry residue . . . . . . 37.80 . . . . . . Coneisting of volatile matter 1-40 . . . . . . Chlorine ... . . . . . . 2-24 ...... 3.29 Nitric Acid (Np. Ob.) . . . . . . 0'11 . . . . . . 2-66 Ammonia . . . . . . . . . o*ooo . . . . . . 0.013 Alhiirninoid Ammonia . . . . . . 0'004 . . . . . . 0.010 The well was closed in by a brick vault. First Sample. Last Sample. Grains per gallon, {fixed salts ... 36*40} ...... ,i This refers t o the usual-mode uf testing if,