Progress of Astronomy during the Year 1879. 471 
and O. Struve’s measures is rather puzzling, the quickly moving 
binaries showing no recularity whatever in the rather considerable 
difference of distances, while pairs moving more slowly or not at 
all show errors varying more gradually according to the distance. 
Considering the great number of measures Madler took they 
would certainly be worth a thorough examination. 
Dr. Doberck publishes elements of 36 Andromede, y Leonis, 
3 3062, OF 298, 4 Aquarii and p’ Herculis, also approximate 
elements of a Centauri (Astr. Nachr.) 
13. Nebule and Clusters. 
The Earl of Rosse has published Parts 1 and 2 (0" to 144 R.A.) 
of the “Observations of Nebule and Clusters of Stars made with 
the six-foot and three-foot reflectors at Birr Castle from the year 
1848 up to about the year 1878” (Trans. R. Dublin Soce., Vol. II.) 
This publication (of which the third part, comprising the last ten 
hours of R.A.,is in the press) embodies all the work done on 
nebulze since the erection of the six-foot telescope in 1845. In 
1850 and 1861 abstracts of the observations on more interesting 
objects appeared in the Philosophical Transactions, but all these 
abstracts are given over again in the new publication with the sole 
exception of the copperplate engravings, to which however in all 
cases references are made in the text. Though not even now every 
single note in the observing ledgers is published, nothing has 
been suppressed which can be of the slightest value or importance. 
The observations are given in the observer’s own words, and the 
notes which were added by Mr. Dreyer while arranging the work 
for publication are easily distinguished by being enclosed in 
brackets. These notes deal especially with questions of identifi- 
cation, and nearly all the new nebule which were found at Birr 
Castle in the course of years and formed the weak point of 
Herschel’s General Catalogue, have now by re-examination and 
comparison with d’Arrest’s observations been identified and their 
positions determined. The work done during the last five or six 
years (1872-78) differs in many particulars from the observations 
taken in earlier years, and with which the paper of 1861 made 
the scientific world acquainted. Most of the more important 
nebulee having been frequently drawn, there was latterly not 
