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3. Note on the Heat of the Stars; by WILLIAM HUGGINS, F.R.S. -In the summer of 1866 it occurred to me that the heat received on the earth from the stars might possibly be more easily detected than the solar heat reflected from the moon. Mr. Becker (of Messrs. Elliot Brothers) prepared for me several thermopiles, and a very sensitive galvanometer. Toward the close of that year, and dur ing the early part of 1867, I made numerous observations on the moon, and on three or four fixed stars. I succeeded in obtaining trustworthy indications of stellar heat in the case of the stars Sirius, Pollux, and Regulus, though I was not able to make any quantitative estimate of their calorific power.

After describing the mode of making his observations with an astatic galvanometer, he observes:

The mean of a number of observations of Sirius, which did not differ greatly from each other, gives a deflection of the needle of 2°.

The observations of Pollux 14°.

No effect was produced on the needle by Castor.

Regulus gave à deflection of 3°.

In one observation Arcturus deflected the needle 3° in 15 minutes. The observations of the full moon were not accordant. On one night a sensible effect was shown by the needle; but at another time the indications of heat were excessively small, and not sufficiently uniform to be trustworthy.

It should be stated that several times anomalous indications were observed, which were not traced to the disturbing cause.

The results are not strictly comparable, as it is not certain that the sensitiveness of the galvanometer was exactly the same in all the observations, still it was probably not greatly different.

Observations of the heat of the stars, if strictly comparable, might be of value, in connexion with the spectra of their light, to help us to determine the condition of the matter from which the light was emitted in different stars.

4. The Total Eclipse of August 7, 1869.-Few astronomical phenomena have probably ever called out a more thoroughly organized system of observation than that arranged for the recent eclipse. The line of total obscuration crossed the North American continent diagonally, entering the territory of the United States at Behring's Straits, in about the 65th degree of latitude, and longitude 90° west of Washington, while it left our shore at the latitude of 34° and the meridian of Washington itself. It traversed a central belt of well-populated territory, yet there seems to have been scarcely a town of any considerable magnitude along the entire line which was not garrisoned by observers having some special astronomical problem in view.

An appropriation was made by Congress, at its last session, for carrying out a series of observations under the direction of the Superintendent of the Nautical Almanac, and Prof. Coffin has succeeded, by the liberal aid of the Navy Department and the very generous and extensive facilities contributed by some of the principal railroads, in providing for an amount of work which for mag

nitude, variety and thoroughness seems large beyond all proportion to the sum placed at his disposal. Three cities in Iowa, Burlington, Mount Pleasant and Ottumwa, were occupied by astronomical, photographic and physical observers under his direction, and special observers, provided with telescopes and instruments for determining geographical position, were sent by him to the North and South, to fix the limits of the belt of total obscuration.

The Navy Department, besides making other provisions, sent observers to the western shore of Behring's Straits; and the War Department detailed Dr. Curtis, to make special photographic observations at Des Moines, Iowa.

The Coast Survey established parties on the Yaken river in Alaska, at Des Moines in Iowa, Springfield in Illinois, and Abingdon in West Virginia, and perhaps at still other stations,-that at Springfield being amply provided with photographic observers and appa

ratus.

Most of the principal observatories likewise organized expeditions of greater or less magnitude. From Washington, the several observers arranged independent series of investigations, stellar, spectroscopic, physical and meteorological. From Cambridge a large party went to Shelbyville, Ky., with large photographic outfit and spectroscopic equipments. From Albany a similar party went to Mattoon, Illinois; others from Clinton and Chicago went to Des Moines, from Cincinnati to Sioux City; and the number of private astronomers who established themselves along the central line, with telescopes and other apparatus of investigation, must have been exceedingly large.

The weather for two days preceding had been unpromising, and in many places almost disheartening; but the efforts of the astronomers were at last rewarded by a day of almost cloudless serenity, with an atmosphere much more transparent than usual, in consequence of the copious rains; and so far as we have heard, the sky was favorable every where, unless a slight haze at Des Moines formed an exception.

It is of course too early, as we go to press, to give any general account of the results, which in most cases are not yet elaborated by the observers; but some matters of interest have been already made known.

The beginning and end of the eclipse seem to have been observed a few seconds later, and the beginning and end of the totality about fifteen seconds later than the predictions of the American Nautical Almanac. As regards the exact position of the central line, and of the limits of the total belt, we have as yet insufficient information to determine the degree of accordance with computation. There can be no doubt that materials have been collected capable of improving the adopted values of the moon's diameter and horizontal parallax.

One of the most interesting results is the introduction of a new and accurate method of determining the time of first contact, by observing with a spectroscope the gradual occultation of the bright lines of the chromosphere. This we owe to Prof. Young, of Dart

mouth College, who formed one of Prof. Coffin's Nautical Almanac party at Burlington. By keeping the center of the slit directed to the point at which the contact is to take place, the observer is forewarned of the approach of the moon's limb, by the shortening of the bright lines belonging to the chromosphere. The line C is well adapted to this purpose, and is seen to grow steadily shorter until it is totally extinguished. The moment of disappearance of the last bright ray is of course that of the first contact, which is thus observed with the same care and accuracy as any other appulsive phenomenon. Although the first contact, as determined in this way by Prof. Young, was noted some five seconds before its recognition by any other observer, it was subsequently found by Prof. Mayer to accord within a small portion of a second with the time as determined by measurement of a series of photographs, taken during the first minute.

Prof. Young also determined the position of nine bright lines during the totality. These corresponded to 694, 10175, 1250±20, 135020, 1474, 2080, 2602+2, 2796 of Kirchhoff's scale, and the line h. (The lines b were seen elsewhere, but this region was not scrutinized by Prof. Young.) Of those named, the 1st, 6th, 8th and 9th are the hydrogen lines a, 8, 7, 8, respectively; the 2d is near D but are refrangible, and was very bright; the 3d and 4th are new, but faint and their position estimated; the 5th is given by both Kirchhoff and Angström as an iron line; the 7th was also faint, and is new, its place being micrometrically determined from 2796.

Of these Prof. Young states that all but three belong to the protuberances; but the 5th certainly, and the 3d and 4th probably, to the corona only, remaining visible when the image of the protuberances was moved away from the slit, and the other lines disappeared. He also finds that certainly one of the lines in the coro na-spectrum, (1474), and probably two others are coincident with auroral lines seen by Prof. Winlock at Cambridge, and reported in the last No. of this Journal.

Prof. Harkness, of Washington Observatory, observed at Des Moines the spectra of five protuberances, no two of which gave the same lines. In the corona spectrum he found no absorptive lines, and but one bright line.

Measures of the protuberances were made by Prof. Rogers, at Des Moines, who found the largest to be nearly a minute and a half high, and observed a peculiar honeycombed or cellular appearance in all of them.

Special search was made for intra-Mercurial planets by Prof Newcomb, at Des Moines, according to the plan suggested by him in the April No. of this Journal, with two 6-inch object-glasses, having a field of about 20' each, and previously clamped to the desired position. A similar scrutiny of the ecliptic near the sun was made by Dr. Gould, at Burlington, in connection with Prof. Coffin's party, using a Tolles telescope of five inches aperture and a field of nearly 2°, provided with occulting discs at the focus. But

neither of these observers nor any others engaged in similar research, found any indications of planets nearer than Mercury.

The photographic observations were very numerous and successful. At Burlington eight impressions are reported to have been taken during totality, by the Nautical Almanac party, and several by the parties at Des Moines, Springfield and Shelbyville. The total number during the partial taken must have been many hundreds.

In our next issue we hope to give more accurate and complete accounts, together with original reports.

IV. MISCELLANEOUS SCIENTIFIC INTELLIGENCE.

G.

1. Eighteenth Meeting of the American Association for the Advancement of Science, held in Salem, Massachusetts, Aug. 1826, 1869.-The Salem meeting of the American Association, under the Presidency of J. M. FOSTER of Chicago, was well attended from all parts of the country. About two hundred and fifty old members from a distance recorded their names as in attendance, and over one hundred and fifty new members were elected. The number of communications entered upon the daily programmes of the Standing Committee was about one hundred and fifty, a full list of the titles of which is appended. The range of these papers was considerable, and it was found expedient to have sub-sections on Archeology and Microscopy, to facilitate the disposal of papers which could not be reached in the other sections.

The recent total eclipse of the sun, (Aug. 7th), was naturally a prominent subject of interest. The astronomers were present in considerable force, and the whole of Monday, the 23d, was devoted in Section A to the discussion of this subject. For a notice of the main points of interest then brought out, reference may be had to the preceding article on this subject.

The dedication of the Peabody Academy of Science, on Wednesday, the 18th of August, was an occasion of interest, worthy to Occupy the attention of the Association at its opening session. This Institution was founded at Salem in the year 1867, by the munificence of George Peabody, with the design of promoting the study of science in his native county of Essex. The first Annual Report of the Trustees of this Academy, made in January, 1869, shows that it is already fully organized, with an able corps of officers and a well ordered museum, library, &c., and the activity of its Director and Curators is evident not only in the extent and fine condition of the collections but in the zeal and ability with which the various publications of the Academy are conducted. Advantage was taken of the present occasion to make the formal transfer of the building of the Museum to the Trustees, and its delivery and acceptance by the Director, F. W. PUTNAM. In an eloquent address the President of the Academy, WILLIAM C. ENDICOTT, Esq., gave the history of the Museum from its foundation, in 1801, as the East India Marine Hall, to its purchase and reorganization in its present form. The Essex Institute, which is well

known by its Proceedings, Bulletin and Historical Collections, is now incorporated with the Peabody Academy of Science.

The address of Dr. B. A. Gould, the retiring President of the Association, was given on Friday evening, (Aug. 20). His theme was the Position of Men of Science in America, and it was treated in his usual felicitous manner.

Every thing which a hearty good will and an intelligent appreciation of science could do was done to promote the happiness and forward the plans of the Association and its members, alike by the city authorities of Salem, the various scientific bodies, and private individuals. The weather was delightful, and every opportunity was embraced for excursions in the neighborhood by land and water. On Saturday the whole Association were the guests of the city government of Salem, on an excursion by steamboat through the bay of Salem and the waters of Boston harbor, visiting the famous Light House built by General Totten on Minott's Ledge, eighteen miles from land, in a situation as perilous and difficult as the famous Eddystone Light;-Fort Warren, notorious as the unwil ling home of many prisoners of eminence during the late war,— and Nahant, where ample provisions were made for the entertainment of the numerous guests in pavilions and along the shores. The sessions closed with a field day, under the auspices of the Local Committee and the members of the Peabody Academy.

The Association stands adjourned to meet on the first Wednes day in August, 1870, at Troy, New York, under the Presidency of WILLIAM CHAUVENET, of St. Louis University.

The following is a list of the papers read at the meeting.*

1. SECTION A. Mathematics, Physics and Chemistry.

On the Total Eclipse of Aug., 1869; B. PEIRCE.

On Quintuple Algebra; B. PIERCE.

Determination of the Mechanical Equivalent of Heat, by means of the modern ice and cooling machines; P. H. VAN DER WEYDE.

The Spectral Bands considered as harmonics of one or more fundamental longer waves, lying beyond in the invisible caloric rays; P. H. VAN DER WEYDE.

On the audible transmission of musical melodies by means of the Electric Teiegraph; P. H. VAN DER WEYDE.

Electricity not a self-existent fluid, but a mode of motion of matter; P. H. VAN DER WEYDE.

On the Classification and the Atomic Weights of the so-called Chemical Elements, with Reference to Stas' Determinations; G. HINRICHS.

Atomic Volume and Atomic Distances of the crystallized AB,C; G. HINRICHS. Molecular Perturbations; G. HINRICHS.

On the Grahamite of West Virginia; H. WUrtz.

Studies in Chemical Geogony, in three parts. Part 1. On the Prozoic Atmosphere and the Ocean of the Zoic Dawn. Part 2. Zoic History from a Chemical View-point. Part 3. Chemical revelations of a Final Zoic Catastrophe; H. WURTZ Flame Temperatures; in their Relations to Compositions and Luminosity; B SILLIMAN and H. WURTZ.

On the Relation between the Intensity of Light produced by the Combustion of Illuminting Gas and the Volume of Gas Consumed; B. SILLIMAN.

On the Composition and Solubility of the Acid Oxalates of Potassium, Ammonium and Sodium; WM. R. NICHOLS.

Classification of the Elements of Matter; C. A. SEELY.

The titles given above are only those which appeared on the daily official programmes, and some of these were read only by title.

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