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“ Should the experiments result in showing that the several waters were alike in their action upon lead, then would the citizens of Boston, in drinking Cochituate water served from leaden pipes and iron mains, be as little liable to lead-disease as are the citizens of Philadelphia and New York who drink Schuylkill and Croton water similarly served, and that portion of the citizens of Boston who have for nearly a quarter of a century employed Jamaica water served through lead. Should Cochituate water be found to act less on lead than Jamaica water, all external circumstances being the same, then would the question be affirmatively and more satisfactorily decided ; since these two waters occur in the same geological associations, are about equally pure, and the latter has been drunk under less favorable circumstances than Cochituate will be, so far as the relations to lead are concerned. On the other hand, should the inequality in action of the waters be great, and that of the Cochituate uniformly most energetic, then would the question, so far as this mode of investigation could influence it, be decided in the negative.

“ The experimental result being favorable, the question of probable future illness to arise from drinking Cochituate water would be decided by an appeal to those physicians of New York, Philadelphia, and Boston, whose extensive practice and standing in the profession demand confidence in their opinions; and by an appeal to public sentiment, where every day's experience among all classes, the less and the more careful, contributes to its formation.

“Such experiments have been made with all the waters above mentioned, and at the same time, in many cases, parallel suites with Albany and Troy reservoir waters, Cambridge well-water, and distilled water, contemplating all the conditions that could be expected to occur. They were conducted in an apartment where, with rare exceptions, no other laboratory labor was carried forward than that connected with this investigation, and in which the tests with hydrosulphuric acid were not made. Whatever influences from temperature or other causes operated upon any one of the waters operated equally upon each of the others. With the exception of Cochituate water, which possessed a yellowish-brown tint, the samples were colorless. A determination of their general relations to each other was made.*

* Professor Silliman, Jr. has made a similar determination of the relations of the Croton, Cochituate, and Fairmount waters. Water-Com. Report, 1845.

Albany Reservoir Water. – 500 cubic centimetres evaporated to dryness in a platinum capsule over a water-bath gave, of solid residue, 0.0924gr. Ignited, the above residue lost 0.0198gr.

Cambridge Well-water, that does not act on lead so as to produce known deleterious effects. — 500cc. evaporated to dryness over a waterbath gave, of solid residue, 0.3918gr.; of which 0.0990gr. were expelled by ignition, and of the non-volatile matters 0.0676gr. were insoluble in boiling water.

Cambridge Well-water, that, in an inch-and-a-quarter pipe several years in use dissolves a grain and a half of lead in thirty-six hours. — 500cc. evaporated to dryness over a water-bath gave, of solid residue, 0.1380gr. ; of which 0.0540gr. were expelled by ignition.

Cochituate Lake Water. – I. 500cc. evaporated to dryness over a water-bath gave 0.0267gr. of solid residue ; of which 0.0122gr. were expelled by ignition, and 0.0050gr. of the remainder insoluble in boiling water. — II. 500cc. over a water-bath gave a solid residue of 0.0267gr.

Croton River Water. — 500cc. evaporated to dryness over a water-bath gave, of solid residue, 0.2175gr. ; of which 0.1496gr. were expelled by ignition.

Fairmount Water, Schuylkill River. - 500cc. evaporated to dryness over a water-bath gave, of solid residue, 0.3007gr. ; of which 0.1032gr. were expelled by ignition, and of the non-volatile matters 0.0239gr. were insoluble in boiling water.

Jamaica Pond Water. — 500cc. evaporated to dryness over a water-bath gave, of solid residue, 0.0268gr. ; of which 0.0115gr. were expelled by ignition, and of the non-volatile matters 0.0070gr. were insoluble in boiling water.

Troy Reservoir Water. – 500cc. evaporated to dryness over a water-bath gave, of solid residue, 0.0593gr.; of which 0.0181gr. were expelled by ignition, and of the non-volatile matters 0.0278gr. were insoluble in boiling water.

“The above results are expressed in tabular form in Table I.

“ The following tables of results will sufficiently explain themselves. They exhibit quantities of lead which, for practical purposes, have little more than relative value in the columns in which they occur.

“ The experiments were made with bars of lead cast in a common mould, of uniform diameter and length. The quantities of water were constant, or as nearly so as might be, in the same series of experi

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ments. The bars were covered, in test-tubes of a given diameter, with fifteen cubic centimetres.

“ After exposure out of direct sunlight, except where otherwise stated, a length of time indicated in the column of days at the left, a suite of similar tubes was filled to the requisite depth with corresponding waters, and the bars transferred with the least delay.

“ The waters were then acidulated with acetic acid, received each a drop of acetate of potassa, — which Fresenius has observed decomposes all lead salts not decomposed by hydrosulphuric acid, — and exposed to a stream of washed hydrosulphuric acid till the liquid became clear, if it had been at first discolored by the precipitate of lead. If concentration occurred, it is so stated. The quantities were estimated by a method to be described farther on.

“ Table I.

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Distilled water, 0.0000 0.0000 0.0000 0.0000 Albany “

0.0924 0.0198 0.0726 Cambridge"

0.3918 0.0990 0.2928 0.0676 Cambridge water

0.1330 0.0540 0.0840 that acts on lead, Cochituate water, 0.0267 0.0122 0.0145 0.0050

0.0267 Croton

0.2175 0.1496 0.0679 Fairmount 16 0.3007 0.1032 0.1975

0.0239 Jamaica

0.0268 0.0115 0.0153 0.0070 Troy

0.0593 0.0181 0.0412 0.0278 “ Table II. — Experiments with Lead to ascertain the Action of Water on Successive Days. – One bar resting on the bottom of each test tube. Waters replaced at the date of each result. Cochituate.

Fairmount.

Jamaica.

Days.

Croton.

5.000 0.500 1.000 10.000 0.100 0.100 0.200 0.100 0.100 0.000

2.000 0.500 0.500 2.000 0.100 0.100 0.200 0.100 0.100 0.000

7.000 0.000 2.000 5.000 0.100 0.100 0.200 0.100 0.200 0.100

10.000
10.000
0.000
1.000
0.500
0.100
3.000
1.000
0.500
0.500

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uniformity in results. It further suggested experiments with suspended bars, the results of which are detailed in the following table.

“ Table V. – Experiments with Bars suspended out of Contact with the containing Vessel. — Waters not exposed to sunlight. Av. erage results of four series of experiments. One bar to each tube. No concentration.

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“ These experiments and the foregoing seemed to show that, without contact of the solid metal with the containing vessel, the influence of the constant condition’ was so far enfeebled, after the first few days, as not to have its effects recognized by the ordinary reagents, without concentration, after a period of twenty-four hours' exposure. The following table of results confirms this deduction.

“ Table VI. — Experiments with Water several Weeks exposed to Light and the Warmth of the Apartment in which the Experiments were made, by which much of the contained Air had been expelled. Bars suspended out of contact with the tube. Volume as in the preceding experiments.

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“ As the street mains are of iron, it was desirable to know if the contact of lead with iron could be more injurious to Cochituate than to Croton, Fairmount, or Jamaica water. Experiments were also made with Albany and Troy reservoir waters, and the Cambridge well-water first in the order of succession in Table I.

* Water concentrated to one fourth of its volume.

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