SCIENCE. 



107 



ASTRONOMICAL MEMORANDA. 

 THE CORDOBA OBSERVATORY. 



In the fall of 1870, Dr. B. A. Gould, formerly director 

 of the Dudley Observatory, Albany, arrived in Cordoba, 

 for the purpose of establishing a National Argentine Ob- 

 servatory, and making the requisite obseivations for 

 forming a complete catalogue of the principal fixed stars 

 of the southern hemisphere. A long delay of about two 

 years, in the receipt of the instrument necessary to make 

 these observations, has been the cause of giving to the 

 world the Uranometria Argentina, a work analagous to 

 the Uranometry of Argelander, which rendered such sig- 

 nal service to astronomy more than forty years ago. 



Cordoba is situated about five hundred miles north- 

 west of Buenos Ayres, the Observatory occupying a 

 height upon the outskirts of the town, in latitude 31 

 25' 15. "4 south; longtitude oh., 51m., 27s., east from 

 Washington. The equipment of the Observatory con- 

 sists of a 12.5 inch equatorial (object glass by Fitz) used 

 mainly for observing comets, etc.; a smaller equatorial 

 of about 8 inches aperture, devoted to observations of vari- 

 able stars ; a Zollner photometer; and various accessory 

 instruments. But the most important instrument is 

 a Repsolds' Meridian Circle of about 8 inches aperture, 

 which was mounted and ready for use in September, 

 1872. With this instrument observations of zones from 

 23 south, to 8o° south declination — 760 zones embrac- 

 ing 106,000 observations — have been completed, and the 

 reductions have been well advanced. To determine ab- 

 solute positions of all stars included in this catalogue, 

 the instrumental constants were determined before and 

 after each zone by a series of observations " consisting 

 of transits of two standard time stars, as well as of one 

 circumpolar star above, and one below the pole, together 

 with measurements of nadir, collimation and level." 



Dr. Gould has established, though necessarily on 

 a limited scale, a Signal Service which will doubtless de- 

 velop rapidly, when meteorology receives more attention 

 in South America than it does at present. Meanwhile 

 data of inestimable value are being collected at very 

 slight expense, by interesting many of the intelligent 

 land owners, in making sucn observations of the bar- 

 ometer, thermometer, etc., as may be made with little 

 outlay of time and trouble. A Time Signal is sent at 

 noon once a week, over the available telegraph lines of 

 the country. 



A force of four observers and several copyists, mostly 

 Americans, is engaged upon the work in the various de- 

 partments, and Dr. Gould has taken with him, within the 

 past few monihs, a photographer, in order to obtain exact 

 representations of several very interesting star clusters, 

 which can be compared directly with the appearance of 

 the cluster at any future time, and thus afford a means of 

 detecting any changes which may occur in the relative 

 positions of the component stars. 



It is to be hoped that the political party now in power, 

 — under whose auspices these institutions have originated 

 and have been maintained — will retain its influence in 

 the government, and thus be enabled to promote the in- 

 terests of science in the country. 



DISCOVERY OF A NEW ASTEROID. 



The Smithsonian Institution has received from Pro- 

 fessor Foerster, of Berlin, the announcement of the dis- 

 covery, by Palisa, of a planet of the tenth magnitude, in 

 eleven hours thirty-nine minutes Right Ascension, eight 

 degrees twenty-five minutes north declination, with a 

 daily motion of one minute, north. This discovery brings 

 the total number of asteroids up to two hundred and 

 twenty, making the eighth discovered since February 6, 

 1880. The date of discovery is omitted. 



In a paper recently read before the Royal Astronomi- 

 cal Society, Mr. Stone has called attention to "some dif- 

 ficulties connected with the determination of the diameter 

 of Mars." Upon examining the Greenwich observations 

 of the diameter, since 1851, very marked personal equa- 

 tions have been noticed in the different observers., dis- 

 crepancies which seem somewhat difficult to account for. 

 Mr. Stone says, " it looks as if there were two different 

 diameters of Mars observed, — one when Mars is compar- 

 atively near to us, and the other when it is at its greatest 

 distance from us. The result is that as far as one can 

 trace it, there is a distinct break of continuity between 

 the smaller and the larger measures ; as if the observers 

 had included the planet's atmosphere when Mars is dis- 

 tant." 



Sweden has decided to take part in the international 

 meteorological and magnetic observations in the Polar 

 regions, and will establish two observatories, one at 

 Masselbay in Spitzbergen, and one at Haparanda at the 

 head of the Gulf of Boothia. Haparanda is to be well 

 supplied with self-registering and printing meteorological 

 apparatus, and with astronomical instruments to carry on 

 a series of regular observations. 



Professor Pickering has called attention to the pe- 

 culiar resemblance between the spectrum of the star 

 Oelizen 17681 and that of the three stars discovered by 

 Wolf and Rayet in 1867, {Comptes Rendus, vol. lxv., 

 p. 292). The relative brightness is found to be different 

 in these spectra, and the subject promises to repay further 

 investigation. W.C.W. 



Washington, D. C , March 3, 1881. 



THE DAVIDSON ASTRONOMICAL OBSERVA- 

 TORY AT SAN FRANCISCO, CALIFORNIA. 



Prof. George Davidson, of the United States Coast and 

 Geodetic Survey, has established a private observatory in 

 San Francisco, and mounted the six-and-a-half inch 

 Equatorial which was exhibited at the Centennial, but 

 which has now a Villarcean governor, spectrescope, and 

 other improvements. 



The geographical position of this observatory is : 



Latitude = 37 47' 22".3 north. 



Longitude = 122 24' 39/.0 west of Greenwich. 



In time = 8 h 09" 1 3 3 .6o west of Greenwich. 

 This fixes it as the most western observatory in America. 



To observe the total solar eclipse of January 11, 1880, 

 Prof. Davidson transported the instrument and the obser- 

 vatory to the summit of Santa Lucia Mountain, about 

 thirty-five miles southward of Monterey, and six thousand 

 feet elevation above the Pacific ocean. In this undertaking 

 everything had to be carried up four thousand feet over a 

 very steep and rugged trail by pack mules ; and the party 

 encountered one ot the fiercest snow stor msof that coast, 

 but successfully accomplished the object of the under- 

 taking which was made under the directions of the Sup- 

 erintendent of the Coast Survey. Whenever opportuni- 

 ties offer for observing at not le'ss than ten thousand feet 

 elevation, he will transport it to these high stations. [It 

 was intended to use it in 1879 at two of the coast survey 

 stations occupied in the Sierra Nevada having elevations 

 of 9800 to 10,600 feet, but unfortunately it was not re- 

 ceived in. season.] 



Mr, Davidson has been engaged in regular coast survey 

 duties upon the Pacific almost continuously since the 

 Spring of 1850, and has had large experience in observing 

 at great elevations. 



An international exhibition connected with electric! 

 will open in Paris, August 1, 1881, and will close on tl 

 15th of November following. 



