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Pedes paris secundi grandes, articulo penultimo ad apicem spinigero, ultimo crassissimo, superficie terminali oblongâ, squamatâ, squamulis spinulâ armatis.
Long. I".- Hab. in corpus speciei Musteli (Squalorum familiæ). – Lect. ad urbem “Rio de Janeiro."
Tribus 4. NYMPHACEA.
Genus ASTRIDIUM. (Dana.) Pycnogono affinis. Caput duobus maxillipedibus subtus instructum parvulis, debilibus, apice obtusis, non prehensilibus. Pedes octo unguiculo confecti. Abdomen perbrevis.
ASTRIDIUM ORIENTALE. — Cephalothorax stellatus, segmentis medio connatis, deinde liberis. Abdomen breve, posticè angustius, obtusum. Truncus buccalis oblongus, subcylindricus, corpore vix brevior. Segmentum corporis primum anticè non transversum, posticè angustius et deinde utrinque longè productum instar rami brevis,* et pedes anticos gerens. Maxillipedes parvuli, obsoleté 3-articulati, obtusi. Pedes crassiusculi, articulo primo vix oblongo, sequentibus sex subæquis, tertio paulo breviore.
Long. I". - Hab. in mari “ Sulu.” — Lect. die 11 Feb., 1842.
Mr. Borden, from the committee to whom was referred the paper of Mr. M. Conant, describing his "Solar Index,” presented a report, entering fully into the investigation of the principles of the instrument. The conclusion which the committee has arrived at is, that, although the “Solar Index” is not susceptible of sufficient accuracy to be used with advantage for nice scientific purposes, yet, as it can be managed with great facility, it may frequently be found valuable to the surveyor and engineer in making experimental surveys, running preliminary lines, &c., for the purpose of learning the character of the topography of a country, and of acquiring, approximately at least, a knowledge of the relative situation of places.
* Hæc pars postica segmenti primi segmentum corporis secundum vere est, quamvis articulatione verâ non sejuncta.
Professor Horsford presented the following communication, embodying the results of his investigations and experiments on the chemical action of water of various kinds upon the materials ordinarily employed for its transmission and distribution.
“ Materials for the transmission of water, to be used as a beverage in any form, should be strong and durable, should admit of ready repair and replacement, be sufficiently cheap to permit general use, and, above all, should impart no deleterious property to the waters served through them. The safety of using water supplied through wooden aqueducts, and the certainty of their rapid decay, are too well known to require more particular mention. Pipes of iron, tin, of tinned iron, tinned copper, tinned lead, glass, and gutta percha, are of comparatively recent introduction. They are believed, so far as experience has shown, to impart few or no deleterious properties to water as a bever. age, though all of them are wanting in some of the essential attributes just mentioned.
“ As pipes of lead have been long in use, and possess in an eminent degree most of the properties required for aqueduct service, and as the following researches have been more especially directed to ascertain the . true value of leaden pipes for the distribution of water, a brief historical sketch of the opinions that have been entertained with regard to the safety of employing them may not be without interest.
“ The period of the first employment of lead for transmitting water is unknown; but the fact that it was condemned by Vitruvius, a Roman architect believed to have lived about nineteen hundred years ago, is evidence of its having at that time been long enough in use to furnish the experience which led to its rejection as a material for aqueducts. * Galen, a physician of Amsterdam, who wrote in the seventeenth century, coincided with Vitruvius. Both had observed the formation of white lead in water-pipes, and attributed to it the illness which was known to affect those who drank certain waters served through leaden pipes. Notwithstanding these strongly expressed opinions and occasional fatal consequences from drinking water containing lead in solu
* Leaden pipes may be seen at this day among the ruins of the Coliseum, and leading to the baths and fountains of Herculaneum and Pompeii.
Kopp thinks lead as a metal was known to the Israelites. Geschichte der Chemie. It is certain that it was known and in use 400 years before the Christian era.
tion, public sentiment continued strongly in favor of this kind of pipes ; and until about the commencement of the present century no experimental examination of the subject had been undertaken. Dr. Lamb of England, and later Guyton Morveau of France, devoted their attention for a time to this inquiry. Their opinions illustrate the uncertainty which attends the earlier labors in every field of investigation. The one believed that most, if not all, spring waters possess the property of acting upon lead to such an extent as to render their conveyance through leaden tubes unsafe, and this because of the salts in solution ; - the other, that many natural waters scarcely act on lead at all, and because of the salts in solution. The former believed that rain or snow water (eminently pure) does not corrode lead; the latter, that distilled water, the purest of all waters, acts rapidly on it. Dr. Thompson of Glasgow subsequently gave some consideration to the subject, and came to the conclusion, that, though Dr. Lamb's general proposition was true, the lead was not dissolved, but suspended merely. Such was the doubt upon this point, - the insolubility of oxide of lead, that a scientific association in Germany made it a prize problem. The honor of deciding the question was accredited to Brendecke, whose views were coincided in by his unsuccessful competitor, Siebold, * and also by Herberger, who prepared his oxide of lead in a different manner, and reported his results at a later period. They decided that oxide of lead is insoluble in water.
“ The imperfection of the investigation and the injustice of this award have since been established by the labors of Yorke, † and Bonsdorff, 1 who have found that aerated, distilled water, deprived of carbonic acid, oxidates metallic lead and dissolves the oxide in the proportion of from
oboth to tatooth. Even the acute Scheele had remarked the same fact in the last century. Philips denied the accuracy of the conclusions of both Yorke and Bonsdorff, and maintained, with Thompson, that the oxide of lead was not soluble, but was only in suspension. His view was supported by the fact, that filtration seemed to separate the lead from the water that originally contained it. In 1846 Yorke reviewed the investigation of Philips, and showed that, in filtration, the oxide of lead enters into combination with the woody fibre of the filter
ing paper. By filtering for some time through the same paper it became saturated, and the lead in solution passed without detention.
“ Christison, to whom we are indebted for a careful record of the principal conflicting opinions upon this subject, repeated and extended the experiments of Guyton Morveau, to ascertain the effect of solutions of certain salts in water. He came to the conclusion that drseniates, phosphates, sulphates, tartrates, and even chlorides, acetates, and ni. trates, possess the power of protecting lead from the action of the water. Of the nature of this protecting power he acknowledges that he has no clear conception. He assured himself that it does not in all cases arise from the formation of an insoluble coat consisting of the acid of the employed salt united to the oxide of lead, by finding that the coat, which for the most part, in his experiments, consisted of carbonate of lead, readily dissolved in acetic acid. This author has suggested that leaden pipes, before being laid down for service, should be exposed a length of time to solutions of some of the salts, denominated protecting ; having observed that leaden pipes, which poisoned certain waters when first served, after a time became coated, and passed the same waters without injury to the health of those who drank them.
“The city of London has long been supplied with water distributed through lead, and though occasional excitements upon this subject have sprung up in Great Britain from individual cases of poisoning, the prevailing public sentiment is in favor of lead. Professor Graham states that in London lead only is used for service-pipes. The exemption of Paris from illness derived from this cause is asserted by Tanquerel.* This is belieyed to be true of all the larger European towns whose inhabitants are supplied with water from public reservoirs. On the other hand, the inhabitants of Amsterdam were poisoned by drinking rain. water that had fallen on leaden roofs; and on replacing the lead with tiles, the maladies ascribed to the former disappeared.
“ We find ourselves at the conclusion of the literature of the Old World upon this subject with these impressions :
“ Ist. That some natural waters may be served from leaden pipes without detriment to health. 2d. That others may not; and 3d. That we have no method of determining beforehand whether a given water may or may not be transmitted safely through lead.
- Professor Silliman, Jr., in his able report on the various waters sub
* Tanquerel on Lead Diseases, edited by Dana, App., p. 396.
mitted to him by the Water Commissioners, in 1845, has given the results of some experiments upon the action of several waters on lead, which conducted him to the general conclusions above expressed.* Among those who have taken strong ground against leaden service. pipes for the transmission of water may be mentioned Drs. Chilton and Lee of New York, and Drs. Dana and Hayes of Lowell.
“ The occasion of the following research was the request by the Board of Consulting Physicians of the city of Boston, in January of 1848, that a comparison of the action of Cochituate Lake, Jamaica Pond, and Croton and Schuylkill River waters upon lead should be instituted, Cochituate water was about to be introduced into Boston for the supply of the city. Jamaica water has been employed in certain sections of the city of Boston since the year 1795, and for the last twenty years served through leaden pipes. Croton River water, since 1842, has been supplied through iron mains and leaden service-pipes to the citizens of New York, a city of 400,000 inhabitants. Schuylkill River water, since the year 1815, has been supplied through iron mains and leaden distribution-pipes to the inhabitants of Philadelphia, a city of 300,000 inhabitants. The inquiry that early presented itself to the Board of Consulting Physicians was the following :- Will there be greater liability to lead-disease from drinking Cochituate water, served through iron mains and leaden pipes, than there is now from drinking Fairmount or Croton waters similarly served, or Jamaica water possibly less favorably served than Cochituate water will be ?
“ To answer this question, Croton, Fairmount, Jamaica, and Cochituate waters were provided with care, and the proposition made that lead should be presented to them all under similar circumstances. It was not proposed to introduce the absolute conditions of actual service in a series of laboratory experiments. It was conceived that, when in contact with lead, all the external circumstances being the same, the differences in the action upon lead would be a kind of exponent of the differences in constitution among the waters. A sufficiently extended series of experiments, it was believed, would reveal all the expedients to be resorted to in order to the fulfilment of the required conditions, and would, if duly extended, furnish replies to the various inquiries in. to which the main problem of the measure of safety or danger resolved itself.
* Boston Water.Com. Report, App., 1845.