ASTRONOMY. 161 



menta for the expeditions sent out by tlie British Government to ob- 

 serve the transit of Venus in 1882 has been j)ublishe(l. It consists 

 almos-t entirely of u discussion by Mr. Stone of the observations of con- 

 tact. Expeditions were sent from Enghmd to Jamaica, Barbadoes, 

 Bermuda, Cape of Good Hope, Madagascar, New Zealand, and Bris- 

 bane, Queenshind, and the observers at all these stations were success- 

 ful, except at Bris))ane, where the weather w^as cloudy. It will be 

 remembered that the English committee did not feel satislied with 

 the photographic work in 1874, and for various reasons they deter- 

 mined in the second transit to put their reliance entirely upon contact 

 observations. From the observations of external contact at ingress 

 Mr. Stone obtains a parallax of 8."7uOiO".122; from tho«e of internal 

 contact at ingress, 8".S2;3±0".023; from those of internal contact at 

 egress, 8".8o5±0".o;5(5, and from external contact at egress 8".953rl: 

 (/'.0-48. The most probable combined result he considers to be 8".8;i2i 

 0".0-.'4, which corresponds to a mean distance of 92,5i>0,000± miles 

 between the earth and sun, with an uncertainty of 250,000 miles. 



The fourth volume of the report of the German Transit of Venus 

 Commission was published in 1887, under the editorship of Dr. Auwers. 

 It contains the observations in detail made with the heliometer by 

 vaiious observers, both before and after the transits of 1874 and 1882, 

 for the i)urpose of determining the instrumental constants. 



The report of the Brazilian expeditions has been printed in a quarto 

 volume of 700 pages. Three stations weie occupied: St. Thomasj in 

 the Antilles; Olinda, Brazil; and Puuta Arenas, in the Straits of 

 Magellan. The transit was observed by projecting the sun's image 

 formed by an eciuatorial refractor of 6.3 inches aperture upon a screen 

 and noting the times of contact. The result given for the value of the 

 parallax from the internal contacts is 8".808. 



Professor Hall, using a value of the constant of aberration 20".4542, 

 deduced from a series of observations of a Lyrae, made at the U. S. 

 Naval Observatory during the years 1802 to 1867, and introducing 

 Michelson and Newcomb's determination of the velocity of light, has 

 lound for the solar parallax 8".810 ± 0".0062. 



PLANETS. 



Mars. — Ttie observations of Perrotin, Terby, and Denning have con- 

 firmed the presence of most of the so-called "canals," or narrow, dark 

 lines, that were discovered by Schiaparelli in 1877, and at subsequent 

 oppositions, and in some cases the gemination or doubling of the canals 

 has been detected. 



Considerable interest has been aroused in regard to Mars on account 

 of the recent changes reported in the markings upon its surface by 

 Perrotin and others. The chief change reported was the apparent in- 

 undation. <>i" disappearance of the "ttiangnlar continent," to which the 

 name of Libya has been assigned, but ihe reijort has not becii conllrnied 

 U. Mis. 142 11 



