-404 



NA TURE 



[February 23, 1893 



The brightness for several years past of stars suspected of vari- 

 ability has been furnished to various astronomers. Plates have 

 been sent to the Lick and Amherst Observatories and to the 

 Smithsonian Institution for special investigations. From one 

 of them a newvariable star in Aries was discovered by Prof. 

 Schaeberle. It is hoped that this use of our plates may in- 

 crease in the future. A large number of photographs were taken 

 of the new star in Auriga. An examination of the older photo- 

 graphs showed that the region containing it had been photon 

 graphed eighteen times from November 3, 1885, to November 2, 

 1891, and that it was then apparently fainter than the thirteenth 

 magnitude. It appeared upon five plates taken between Decem- 

 ber 16, 1891, and January 31, 1892. After its disco^%ry it was 

 photographed on sixty-five chart plates and thirty-six spectrum 

 plates, until April 6, when it became too faint to be visible in 

 the encroaching twilight. All of these plates have been care- 

 fully studied and measured. Twenty-one charts and fifteen 

 spectrum plates of this object have been taken since its reappear- 

 ance in September, 1892. On these last plates, the spectrum is 

 shown to resemble that of a planetary nebula. 



Many photographs of the lunar eclipse of November 15, 1891, 

 were taken both at Cambridge and at the Boyden observing 

 station near Arequipa, Peru. The examination of these photo- 

 graphs for the detection of a possible lunar satellite led only to 

 a negative result. 



The number of photographs taken with the ii-inch Draper 

 telescope is 996. They include 372 spectra of ;3 Aurigae 

 to determine the law of periodic doubling of the lines. 244 

 of these images show the lines double so that the separation 

 pan be measured. In like manner 208 spectra of C Ursse 

 Majoris have been photographed, and in 49 of them the 

 lines are separated widely enough to be measured. A similar 

 study has been made of the new star in Auriga, of yS Lyrse, 

 of II Monocerotis, and of some other stars having peculiar 

 spectra. Photographic charts have also been obtained of numer- 

 ous variable stars, stars having large proper motion, clusters 

 ^nd s.tars having peculiar spectra to determine their parallax- if 

 it is perceptible. 



Boyden Department. 



In establishing the fund that bears his name, Mr. Boyden 

 desired to secure an astronomical station where the effects due 

 to the atmosphere would he greatly diminished. This has now 

 been successfully accomplished in the Harvard Station at Are- 

 quipa, Peru, where the effect of the air is no longer as hereto- 

 fore the principal obstacle to progress in astronomy. Instead 

 of this the limit is now the size and excellence of our instru- 

 ments. A great advance would probably be made in our 

 knowledge of the planets, and pei-haps of the fixed stars, if a 

 telescope of the largest size could be mounted under such favour- 

 able conditions. 



This station has continued in charge of Prof, W. H. 

 Pickering. The instruments chiefly employed have been 

 the 13-inch telescope, the 8-inch Bache telescope, and a 

 photographic camera having an aperture of 2\ inches. The 

 first of these instruments has been largely devoted to visual 

 work, for which unusual advantages are aftorded by the 

 transparency and steadiness of the air at this station. Many 

 interesting results have been derived from the observations 

 made of the moon and various planets. The observations of 

 the moon relate to Plato and other regions, which have been 

 carefully examined, and also to the systems of bright streaks 

 visible at full moon. The markings of Mercury have been 

 studied, and this investigation appears to confirm Schiaparelli's 

 view that the rotation of Mercury on its axis occui)ies the same 

 time as its revolution in its orbit. Although this planet appears 

 to have no atmosphere, the markings upon it are very faint com- 

 pared with those upon the moon. Venus was micrometrically 

 studied near its inferior conjunction with regard to its diameter, 

 polar compression, and the refractive effect of its atmosphere. 

 No permanent markings could be detected. An extensive series 

 of observations was made upon Mars. The relative positions 

 of 92 points upon its surface were determined by the micro- 

 meter. More than forty minute black points were discovered, 

 provisionally designated as lakes. 'I'he polar compression 

 of the planet was measured, and appeared to be greater than 

 that indicated by theory, which may be due to an excess of 

 cloud in the equatorial regions. The presence of the dark and 

 narrow streaks called canals by Schiaparelli has been confirmed 

 and various measurements of them have been made. The 

 clouds projecting beyond the limb, and terminator, discovered at 



NO. 12 I 7, VOL. 47] 



the Lick Observatory, have been studied, and their height has 

 been found to be at least twenty miles. The relative colours of 

 different portions of the planet have been minutely observed. 

 Two large dark blue areas have been detected, and other por- 

 tions have been noticed to be subject to gradual changes of 

 colour. 



Many new double stars were found in a survey of the 

 heavens south of 30°, between I2h. and i8h. The August 

 occultation of Jupiter was observed both visually and photo- 

 graphically, as was also the new star in Auriga and Swift's 

 comet, the photographs of which showed detail not noticeable in 

 the visual observations. 



With the camera, having the aperture 2| inches, very satis- 

 factory photographs have been obtained of the Magellanic 

 clouds, showing their composition to be partly of stars and 

 partly of nebulous matter ; also the spiral structure of the larger 

 of the two clouds. 



Meteorological observations are regularly carried on. Stations 

 have been established at MoUendo, 100 feet above sea level, at 

 La Joya, the elevation of which is 4,150 feet, at the observing 

 station, 8,060 feet high, at the Chachani Ravine 16,650 feet 

 high, where numerous miscellaneous observations have been 

 made. Notwithstanding the great height of the last-named 

 station, it can be reached by a mule path, and a hut has been 

 erected where the observers can pass the night. A survey of 

 the Arequipa valley and neighbouring mountains has been 

 made, depending on two separate base lines. The heights of 

 the mountains have been measured, and in some cases the 

 result has been checked by a mercurial barometer. 



The Bruce Photographic Telescope. 



This instrument, which if successful will be in many respects 

 the most powerful in the world, is now rapidly approaching 

 completion. The eight surfaces of its objective have been 

 ground and polished so that it could be tested on a star. The 

 results were satisfactory, although, of course, no definite 

 opinion can be formed until the final corrections are applied. 

 The focal length proved to be that desired within half of one 

 per cent. Plans have been made and the foundations laid for a 

 one-story brick building with a sliding roof, in which it will be 

 erected during its trial in Cambridge. After this it is proposed 

 to send it to the Arequipa station in Peru. 



Photographs have been taken with the transit photometer 

 on 192 evenings, and when clear, throughout the entire night. 

 With this instrument images are obtained of all stars brighter 

 than the sixth magnitude which cross the meridian during the 

 night. The value of this work was illustrated when the new 

 star in Auriga was discovered in February, 1892. It then ap- 

 peared that this object had been photographed on twelve nights 

 since December 10, 1891, while no trace of it was visible on 

 thirteen plates covering this region and taken before December 2, 

 1891. The only knowledge that exists of its changes of light 

 during the six weeks in which it remained undiscovered is fur- 

 nished by these photographs and those taken with the 8-inch 

 telescopes. It was also photographed with the transit photo- 

 meter on twelve nights after its discovery. Of the forty thou- 

 sand standard stars of the tenth magnitude about eight thousand 

 have been selected by Miss E. F. Leland during the past year, 

 making eleven thousand in all. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Oxford. — In the Chemical Department Prof. Odling is 

 lecturing on the glucoses, Mr. Fisher on inorganic chemistry, 

 Dr. Watts on organic chemistry, and Mr. Veley on physical 

 chemistry. There are about sixty students working in the 

 laboratories, and a few of the senior men are engaged in re- 

 search. 



Among the apparatus belonging to the late Duke of Marl- 

 borough, presented by the Duchess, are three large spectro- 

 scopes by Hilger, one having five prisms, another being a direct 

 vision spectroscope 5 feet 6 inches in length, two balances by 

 Deleuil; a mercury pump by Alvergniat, Dumas' vapour density 

 apparatus, Thomson's electrometer gramme machine, large 

 Rhumkorf coil and a quantity of valuable glass apparatus. There 

 are besides a number of specimens of compounds of rare 

 earths. 



The Regius Professor of Medicine has placed his pathological 



