January i, 1892.] 



SCIENCE. 



some fields, gently sloping towards a depression in the mid- 

 dle, until we reach another little creek, flowing south into 

 the Tohickon. The explanation of this seems to be as fol- 

 lows: Beaver Creek originally flowed out to the south-east, 

 across the present divide, into the Tohickon, having a similar 

 course to that of the Tohickon in that it crossed the strike of 

 the beds. Tinicum Creek, gnawing along its easier path, 

 reached and captured Beaver Creek, at the point where the 

 sharp turn is seen. The divide which originally stood close 

 to the Tinicum has now been pushed south until it occupies 

 a position close to the letter B in the figure. 



The beheaded portion of Beaver Creek still occupies the 

 old valley, while an inverted stream now flows north in a 

 directly opposite direction to that of the original Beaver 

 Creek. The old valley across the divide to the Tohickon is 

 seen as the gentle depression in the fields. 



This explanation shows us why there is the sudden turn 

 in the Tinicum just at this point. It has worked back on its 

 easy course until it has captured Beaver Creek, and, as 

 shown above, is continuing its work by pushing back towards 

 the Tohickon, which it will very soon capture in the same 

 way. R. DeC. Ward. 



Harvard College, Oct., 1891. 



ASTRONOMICAL NOTES. 



M. Palmieei, director of the Vesuvian Observatory, is re- 

 sponsible for the statement that all the great eruptions of 

 Vesuvius take place at new or full moon, and especially 

 eclipses. The eclipse of June 17, 1890, was accompanied by 

 violent earth currents. On the other hand. Captain de Mon- 

 tessus, who has patiently accumulated observations and data 

 concerning earthquakes, has now a catalogue of more than 

 60,000 of these phenomena, individually discussed. He es- 

 tablishes that earthquakes are distributed uniformly through- 

 out the day and night, that they have no relation to moon 

 culminations and astronomical seasons, and that such coin- 

 cidences which have been claimed in the past rest on insufiB- 

 cient ground. 



M. Jaussen, the eminent French astronomer, has been 

 attempting to find solid rock on the top of Mount Blanc, upon 

 which to build an observatory. His scheme has been to bore 

 galleries through the ice, but so far he has been unsuccessful, 

 and he is considering the feasibility of founding an observa- 

 tory on the ice. 



In the December number of Knowledge will be found re- 

 productions of photographs, taken by Dr. Max Wolf of 

 Heidelberg, of the region of the Milky Way in the con- 

 stellation Cygnus, and also in the constellation Sagitarius. 

 Mr. Ranyard, the editor of Knowledge, in an article enti- 

 tled " Dark Structures in the Milky Way," calls attention to 

 several interesting facts connected with the region of the 

 heavens shown in the photographs. One of the regions cov- 

 ered is that surrounding Alpha Cygnus, and directly above 

 that star is seen a dark, branching, tree-like structure. It 

 evidently corresponds to a branching stream of matter which 

 cuts out the light of the nebulous background on which it 

 seems projected, and it is evidently intimately associated 

 with the lines of stars which border the stream and its 

 branches on either side. A somewhat similar dark branching 

 stream may also be traced on a photograph of the region 

 surrounding Epsilon Cygni, a copy of which appears in 

 the October number of the journal above quoted. Altogether 

 the article, with its attendant photographs, is very interest- 

 ing, and brings to light some new facts connected with that 



region of the heavens in which the stars seem almost count- 

 less. 



The small planet discovered by Dr. J. Palisa of Vienna, 

 on Aug. 30 (now numbered 313), has been named Chaldea. 



In a very interesting paper in No. 3,066 of the Astro- 

 nomische Nachrichten, Professor Auwers gives the sun's 

 parallax as 8.880", with a probable error of ± 0.022" This 

 value is the result of the determination from the German 

 Transit of Venus expeditions in 1874 and 1882, during which 

 years 754 measurements were made. Professor Harkness, in 

 his discussion of the results of the American Transit of Venus 

 Commission, from the photographs alone, obtained the value 

 8.842" for the sun's parallax, with a probable error of 

 ± 0.011". From a discussion of all the data obtainable, he 

 obtained 8.80905" ±0.00567". This latter value corresponds 

 to a mean distance of 92,796,950 miles from the earth to the 

 sun, while Professor Auwers's value corresponds to a distance 

 of 91,814,000 miles. 



The following is a continuation of the ephemeris of Win- 

 necke's comet. The epoch is for Berlin midnight. 



1892 R.A. Dec. 



h. m. s. ° ' 



Jan. 12 12 28 12 + 13 38 



13 29 8 13 42 



14 30 4 13 47 



15 30 58 13 52 



16 31 53 13 57 



17 32 46 14 3 



18 33 39 14 9 



19 34 31 14 15 



20 35 22 14 22 



21 12 36 13 + 14 28 



The following is a continuation of the ephemeris of Wolf's 



comet. The epoch is for Berlin midnight. 



1892 R.A. Dec. 



h. m. s. o ' 



Jan. 11 4 16 43 — 13 2 



12 17 5 12 54 



13 17 29 12 45 



14 17 55 12 37 



15 18 22 12 28 



16 18 51 12 19 



17 19 21 12 10 



18 19 52 12 1 



19 20 24 11 52 



20 20 58 11 43 



21 4 21 33 — 11 33 



G. A. H. 



THE GRADUATE STUDENTS' ASSOCIATION OF JOHNS 

 HOPKINS. 



The Johns Hopkins University Circular for November gives the 

 names of graduate students in that university from nearly every 

 State in the Union. Nearly all the Canadian provinces and sev- 

 eral foreign countries are represented. These three hundred stu- 

 dents are here, primarily for hard work, each in his specialty, in 

 one of fourteen departments. Not a few of the students enrolled 

 last year are now studying in European universities, with the 

 expectation of returning to their work here at the beginning of 

 the next year. 



There must be departmental isolation in every university, but 

 this may become extreme. The best training for a capable and 

 cultivated manhood can be obtained only as one mingles with 

 his fellows and shares their varied experiences. An organization 



