July 5, 1895.] 



SCIENCE. 



TSE GENERIC NA3IE OF THE WATEB-WEED. 



The first generic name applied to our 

 common Water-weed or Ditch-moss was 

 Elodea, published by Michaux (Fl. Bor. 

 Am. I: 20. 1803), who gave a description 

 accompanied by a figure of the North 

 American plant specifically designated by 

 him Canadensis. This name was unavail- 

 able on account of the prior publication of 

 Elodes Adans. (Fam. PI. 2: 444. 1763), 

 the same word with a different spelling. 

 Adanson's genus was based on Hyperieimi 

 jEgypticum Linn.; it has been accepted by 

 Payer (Organog. 8, pi. I.). Hyjjerieum 

 ^gypticum was also made by Spach the type 

 of the genus Triadenia (Ann. Sci. Nat. II. 

 5: 172) as T. microphylla. It is noteworthy 

 that Spach in the paper above cited cred- 

 ited Adanson with the name Elodea and 

 founded a new genus Elodes in addition, thus 

 ■complicating the synonymy of these Hyper- 

 icacese in an extraordinary manner. 



Elodea Michx., being thus clearly unten- 

 able, authors have at different times pro- 

 posed no less than six generic names for the 

 "Water- weeds. In seeking for the oldest of 

 these, Morong (Mem. Torr. Club, 5: 27) 

 has recently accepted Udora Nutt. (Gen. 2: 

 242. 1818), but Philotria Raf. (Am. Month. 

 fj" Mag. 2: 175. Jan. 1818.) was published a 

 few months earlier, and appears to be the 

 first available for these plants. The North 

 American species is Philotria Canadensis^ 

 Elodea Canadensis Michx. 



N. L. Britton. 



NOTES ON THE PBOGBESS OF A8TB0N0MY 

 DUBING THE YEAB 1S94.* 



MINOE PLANETS. 



TwENTY-THEEE new plaucts were dis- 

 covered. Permanent numbers have been 

 assigned from 379 to 390, both inclusive. 

 Eleven have, as yet, been unnumbered, as 



* Based mainly upon the Annual Report of the 

 Royal Astronomical Society of London. February, 1895. 

 Prepared at the request of the responsible editor. 



the investigations in regard to their orbits 

 are not sufficiently complete.* The dis- 

 coverers were as follows : Charlois at Nice 

 11, Courty at Bordeaux 2, Wilson at North- 

 field, Minn., 1, Wolf at Heidelberg 6, Bi- 

 gourdan at Paris 1, Borelly at Marseilles 1, 

 Eoberts at Crowborough 1. 



Minor planets are now picked up so rapidly 

 by photography and other methods that, to 

 avoid confusion in the numeration. Prof. 

 Kreuger, of Kiel, assigns a provisional rota- 

 tion (A, B, C, etc., BA, BB, EC, etc.), ar- 

 ranged in order of their announcement to 

 the ' Telegraphische Central-Stelle. ' The 

 final number is assigned by Prof. Tietzen, 

 Director of the Rechen-Institut in Berlin. 

 Numbers are assigned to those planets only 

 for which sufficient observations are avail- 

 able for a determination of the orbits. 

 Names are given by the discoverers. 



Planet BE discovered November 1, 1894, 

 by Wolf, is unique, having the smallest peri- 

 helion distance of all the minor planets, ex- 

 cept possibly No. 323, Brucia, which was 

 named after Miss Bruce of New York City, 

 on account of her generous contribution 

 to astronomical work. The least distance 

 of BE from the earth and Mars are about 

 63 and 21 millions of miles. It seems to 

 be well adapted for determining Solar 

 Parallax. 



Prof. E. E. Barnard measured, during the 

 year, the diameters of Ceres, Pallas and 

 Vesta with the great telescope of the Lick 

 Observatory and obtained the results as 

 follows: Ceres, 520 miles; Pallas, 304 

 miles ; Vesta, 241 miles. These planets are 

 the largest of the family. 



COMETS. 



Five comets were discovered. 

 (a) Denning, of England, picked up the 

 first on March 26, 1894. 



Investigations seem to show that this 



* Numbers have since been assigned up to and in- 

 cluding 401. 



