Miscellaneous Intelligence. 371 
|’ the mean duration in the later hours of the night. Such decrease,is dis- 
 tinctly shown by Wartmann’s observations in 1838. H. A. N. 
6. Heights of Auroral Arches.—Mr. B. V. Marss has obtained data 
for computing the altitudes of three auroral arches. A fine arch was 
seen early on the evening of the 16th of January, 1865, and from observ- 
ations at Germantown, Pa. and Brunswick, Me., the computed altitude 
js 97 miles. A second arch on the 20th of February was observed at 
is 794 miles. A third arch on the 21st of February, observed at Boston 
and Philadelphia, had the computed altitade of 57 miles The mean 
height of the three arches was therefore 78 miles. The data were not 
very exact in either case, but taken together they are believed to furnish 
reliable approximations. H. ALN 
VY. MISCELLANEOUS SCIENTIFIC INTELLIGENCE. 
1. The Agassiz Expedition to South America.—On the 29th of March, 
Prof. Agassiz, with a large corps of assistants, sailed in the steamer 
Colorado for Rio Janeiro, on an exploring tour in South America, 
His corps consists of O. H. Sr.Jouw and C. F. Harrr to collect fossils 
and to aid in geological exploration, J. G. Aytnony to collect mollusks, 
. A. ALLEN to collect birds and mammals, G. Scrva to make skeletons 
of mammals, birds, the large reptiles and fishes, and Mr. Burxwarpt 
to make drawings. Prof. Agassiz will devote himself, with native and 
vertebrates, yet will have, for his main object, the study of the embry- 
Am 
The party is accompanied also by Dr. B. E. Cotting as surgeon, with 
the wives of Prof. Agassiz and Dr. Cotting, a son of Mr. N. Thayer of 
Boston, and a son of Mr. 8. G. Ward of that city. ! 
The expedition goes first to Rio Janeiro, whence the geological as- 
Professor Agassiz at first intended only a visit to Brazil for his health, 
and proposed to take along one or two assistants to aid him in making 
collections for the Museum of which he is Director at Cambridge. On 
Projected tour of exploration, immediately tendered to Professor Agas- 
siz and his wife free passage to R 
Mr, Thayer’s munificent proposition, Mr. McLane, in the name of the 
Director of the Company, offered to the whole party free passage in the 
new steamer Colorado, about sailing for Panama va Cape Horn. The 
arrangements were soon completed, and within three weeks after Mr. 
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