584 EEPORTS OF EUROPEAN OBSERVATORIES. 



observed. Advantage was taken of this inactivity to examine the 

 periodic errors in the micrometer screw, which was done twice: the 

 micrometer, meanwhile, being taken apart and cleaned. The errors dis- 

 covered were very small, less than 0". 04. 



The northern hemisphere of Mars being somewhat free of snow daring 

 first four months of 1878, I was able, in some measure to complete the 

 topographical map of that planet made during the previous year. 

 During the same period we observed the aspects of Venus, and made 

 many sketches before and after the inferior conjunction. The results 

 were not satisfactory, but we will continue observations for two other 

 inferior conjunctions to have the aspect under all geocentric longitudes. 



Professor Celoria has reduced the meridian circle observations made 

 during 1871-'2. In the first six months of 1878 he made with this in- 

 strument 1,200 observations on stars of rapid movement and on the prin- 

 cipal ones of the new doubles of Mr. Burnham. In the last six months 

 the construction of the adjoining tower of the registering anemograph 

 has prevented observations with the circle. In the mean time Professor 

 Celoria devoted himself to preparing for publication his calculations of 

 longitudes made in 1875, and continued his studies of ancient eclipses. 



The determination of time for the use of the observatory and the city 

 has been made by Dr. Frisiani — who also has charge of the meteorologi- 

 cal observations — and assistant, Dr. Rajna. 



A new equatorial refractor of 18 French inches aperture is being made 

 for the observatory by A. licpsold, of Hamburg. 



UNIVERSITY OBSERVATORY, MOSCOW, 

 (Dr. Tu. Brediciiin, Director.) 



Professor Bredichin continued his spectroscopic observations of the 

 Sun, observed on Jupiter, and made microscopic measurements of the 

 star Algol and of some star-groups. 



The tails of the following comets were computed by him: 1577, 1618 

 (3), 1665, 1807, 1811, 1823, 1835, 184-3 (1), 1845 (3), is.-):; (2), IS.-).", (3), 

 1853 (1), 1854 (2), 1854 (3), 1S57 (3), 1858, 1860 (3), 1862 (2), 1803 (4), 

 1877 (2), and a memoir published on comets. ■ 



Mr. Ceraski continued his photometric observations of stars. 



Messrs. Belopolski and Socoloft observed the August meteors, and 

 made a series of meridian observations of stars with independent mo- 

 tion, and examined the errors of the microscope and of the meridian 

 circle. 



Mr. Belopolski continued his photographic observations of the Sun. 



ASTRO-PHYSICAL INSTITUTE, POTSDAM. 



The buildings are progressing and some of them are being occupied, 

 temporarily, by the laboratory and the library. A temporary structure 

 was erected in 1874, for heliographic experiments. 



