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“ TABLE VII. — Experiments with Lead and Iron. — Iron upper. most. Lead solder. Volume of water as in previous experiments.

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8.000 1.000 2.000 1.000 1.000 10.000 10.000 25.000 7 10.000 0.010 | 0.010 0.010 0.010 0.010 0.500 0.000

9 2.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 111 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 20 0.000 0.100 0.000 0.100 0.000 0.000 0.100 0.000 30 1.000 0.400 0.500 0.800 0.500 0.500 0.500 0.100 48 0.100 | 0.005 0.100 0.010 | 0.050 0.000 0.010 Lost.

“ The discoloration of the bars of lead was least in this order :- Albany, Cambridge, Croton, Fairmount, Distilled Water, Jamaica, Cochituate. That is, Cochituate, apparently, most promptly and completely coats the lead.

“ Table VIII. — Experiments with Lead and Iron. – Lead uppermost. Lead solder. Volume of water same as in previous experiments.

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2 0.500 0.500 0.500 0.500 0.500 0.500 0.500 0.500 3 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 7 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 16 0.010 | 0.010 | 0.1001 0.010 | 0.010 0.010 | 0.010 | 0.010 26 0.500 0.100 | 0.010 | 0.010 | 0.010 | 0.010 0.010 | 0.010 44 3.000 0.050 0.100 | 0.100 1 0.100 1 0.100 | 0.100 | Lost.

“ Sections of each bar at first less coated near the iron. Larger measure of protoxide of iron in Cochituate and Croton waters than in the others, as indicated by ferrocyanide of potassium. Discoloration of the bars least in this order : - Fairmount, Distilled Water, Albany, Troy, Croton, Jamaica, Cochituate.

Table IX. — Experiments with Lead and Iron. — Soft solder. Volume and other conditions as in previous experiments.

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10.000 6.000 6.000 6.000 1.000 10.000 7.000 7.000 12 . 1.000 Lost. / 1.000 / 1.000 / 1.000 / 1.000 2.000 17 | 30.000 0.000 0.050 0.010 0.500 0.000 0.500 0.000

“As the stopcocks will, many of them, be of brass, it was important to ascertain the influence of this connection.

“ Table X. — Experiments with Lead and Brass. — Surfaces of lead and brass nearly equal. Volume of water as before mentioned.

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1 5.000

| 8.000 7 20.000

| 10.000 37 20.000

12.000
2.000
1.250

1.500 43 | 2.000

2.000 0.500 0.800 25.000 0.100 1.000 5.000 2.000 1.500 1.500 2.000 1.500 1.500 8.000 0.800 10.000 10.000 2.000 1.500 20.000 7.000 0.100 | 7.000 0.200 0.100] 0.100 4.000 7.000 0.800 10.000 2.000 10.000 1.000 8.000 5.000 0.800 0.800

0.400 0.800 0.300

0.400 0.400 0.600

0.800 0.250

0.800 1.200 0.500

0.800

“As some stopcocks may be of copper, a suite of experiments was made to ascertain the effect of this union.

- TabLE XI. — Experiments with Lead and Copper. — A bar of lead and copper nail three fourths of an inch long. Lead solder.

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“ Table XII. — Experiments with Lead and Tin. — A half-bar of each soldered without alloy. Volume of water as before mentioned.

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“ Variation in some of the properties of the Cochituate water might be expected to take place. First, in the percentage of organic matter. Second, in temperature. Third, in percentage of salts..

“ The effect of increasing the percentage of organic matter is exhibited in the following table.

“Table XIII. Experiments with Lead in graduated Solutions of Organic Matter (Tannin) in Cochituate Water.

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.“ The bars of the third and fourth columns became more or less coated with a loose reddish-brown coat of organic matter and lead. The influence of increased organic matter of this form (which is as nearly allied to the vegetable matters that might be expected to occur in lake water as could be readily found) was to lessen the action on lead. The organic matters of lake and river waters consist of living and deceased organisms, animal and vegetable, and of soluble substances derived from decaying vegetation. When exposed a sufficient length of time, these matters become thoroughly inorganic. The carbon becomes carbonic acid, and the hydrogen becomes water, by the consumption of oxygen in solution in the water.

“My experiments have shown, that, if the quantity of organic matter, such as the extract of bark, be more than totoo of the weight of the water, precipitates of the organic matter in combination with oxide of lead, if any is in solution, will take place. This is one of the meth. ods frequently resorted to for separating organic bodies from solutions.

* A kind of fungous or flocculent mass fell with the lead, augmenting the vol. ume of the precipitate.

+ This precipitate is visible in Croton service-pipes five years in use. It occurs in the Jamaica service-pipes in Boston, and, I have been informed, in those of Fairmount water in Philadelphia.

VOL. II.

10

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“The effect of temperature was sought in a variety of ways.* The following experiments are recorded.

“ Table XIV. - Experiments with Bars previously coated, exposed to direct Sunlight from the 21st to the 26th of June. — Bars resting on the bottom of the tubes.

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“The influence of extreme temperature and exposure to air and moisture, under the most favorable circumstances, was ascertained by transmitting steam mixed with air through a leaden pipe thirty-six feet long, coiled like a still-worm, and placed in cold water to produce condensation. One hundred and ten cubic centimetres of the condensed water, after acidulation with acetic acid, were treated with a stream of hydrosulphuric acid. The precipitate was collected on a filter, previously dried at 100° C., and gave 0.0225gr. of sulphide of lead, equal to 0.0196gr. of lead; which is equivalent to 0.8095gr. of lead in a gal. lon. Whatever influence might result from such changes, it must be remembered that pipes under ground will preserve a tolerably even temperature ; and be the effect of increased heat what it may, it has been more energetic in Philadelphia than it ever can be in Boston.

“ The effect of increasing the percentage of common salt is exhibited in the following table.

“ Table XV. – Experiments with Cochituate Water and graduated Solutions of Common Salt. - Bars and volumes as in the foregoing experiments. No concentration. Bars resting on the bottom of the tubes.

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* Dr. Hayes has observed that elevation of temperature increases the quantity of lead dissolved in a given time. — Report of the Consulting Physicians, 1848, p. 24.

" These results show,

“ Ist. The immediate effect of the salt in preventing the action on lead by lessening the solvent power for air; and

“ 2d. The influence of salt in dissolving the coat formed, by double decomposition, or by the formation of the double salt of the oxide and chloride ; as shown in the last suite of results.

“ The preceding experiments, as a whole, go to show that Cochituate water may be distributed through iron mains and leaden service-pipes with as little danger as Schuylkill, Croton, or Jamaica water.

“ The consideration that was to give value to these determinations was that of the health of the citizens of Philadelphia, New York, and Boston, so far as it might be influenced by the waters served through lead in the respective cities. This was to be decided, as already intimated, by an appeal to the most enlightened testimony that could be furnished ; that of eminent physicians of extensive practice in the localities where lead pipe is employed.”

Professor Horsford then adduced a summary of the numerous medical opinions, chiefly compiled from letters addressed to himself, and which have been already published in the Appendix to the Water-Commissioners' Report of August 14th, 1848.

“ The decision of this question does not depend upon the presence or absence of a minute quantity of lead in water that has been standing a given length of time in leaden pipes, or upon the absolute freedom from corrosion of pipes long in use. For if a certain quantity, more or less, has found its way into the human system in the every-day regular use of Croton and Schuylkill waters, then must the human system be capable of sustaining without injury this quantity ; and the possibility of receiving an equal quantity hereafter by those who drink Cochituate water may be contemplated without solicitude, since the experiment has been made.* Nevertheless, examinations for lead have been made in many well-waters, and also in Croton, Jamaica, Schuylkill, and Troy waters, and Dedham spring water. The results follow.

* To this point more particular reference will hereafter be made.

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