6i6 



NA TURE 



{Oct. 23, i! 



New Southern Doubi.e-stars.— Mr. H. C. Russell, 

 Government Astronomer at Sydney, has circulated a list of 

 newly-detected double-stars, some found by himself with the 

 large instrument, and others by Mr. Hargrave with the 7^-inch 

 equatorial. In most cases the components belong to the tenth 

 and eleventh magnitudes. 



The Total Solar Eclipse of 1S16, November 19. — The 

 firsl total eclipse of the sun in the present century in which the 

 central line passed over Europe took place on the morning of 

 November 19, 1S16. Maps of its track appeared in the Berliner 

 Jahrbuch for 1816, and in the first part of Hallaschka's Ele- 

 menta Eclipsium, where the full computation of this eclipse is 

 given as an example. In Lindenau and Bohnenberger's Zeit- 

 schnft fiir Astronomie, vol. v., Hagen gives the moon's place 

 deduced from Burckhardt's Tables, with the horizontal parallax 

 and semi-diameter : if we combine these with similar quantities 

 for the sun, taken from Carlini's Tables of 1S33, we find the 

 following elements of the eclipse : — 

 G.M.T. of Conjunction in R.A. 1816 Nov. 18 at 2lh. 46m. 57s. 



R.A 



Moon's declination 



Sun's ,, 



M' ■ 1 hi irly motion in R.A. 



Sun ,, ,, 



Moon's ., ,, Decl. 



Sun's „ (J fl 



Moon's parallax ... 



Sun's ,, 



Moon semi-diameter ... 



Sun's ,, 



234 42 20 

 .8 37 9 S 

 19 30 29 S 

 3658 

 2 37 

 n 37S 

 o 38 S 

 60 15 

 o 9 

 1625 



In the Berliner Jahrbuch Bode makes the eclipse total at both 

 Dantzic and Warsaw ; the above elements do not show totality 

 at either place, but give the magnitudes 0-990 and 0-992 1 ■ pec 

 lively. They indicate, however, a total eclipse at Bromberg, 

 duration im. 22s. Possibly there may be other observations of 

 the totality on record, but the only one we have found was made 

 by Hagen at Culm in Bohemia, where he observed its com- 

 mencement but not the ending. It would appear that the 

 weather at this season was an impediment to observation, or 

 more details of the total phase in its passage over Germany might 

 have been expected. Before the eclipse of July 1842 there was 

 only one in which the line of totality approached near the 

 European continent, viz. that of July 17, 1833, which was total 

 in Iceland ; on Mount Ilccla the total eclipse commenced at 

 4I1. 56m. 37s. a.m., and continued two minutes, the sun at an 

 altitude of 13° ; but the days of physical observations had not 

 then arrived, and we do no; find it recorded that a midsummer 

 expedition to Iceland was 01 janised. 



CHEMICAL NOTES 

 THERE has of late been a considerable amount of work done 

 on the relations between the composition and structure of 

 chemical compounds and various physical constants of these 

 compounds ; and also on the relations between the conditions of 

 chemical change and some of the physical properties of the con- 

 stituents of the changing systems. Among the more important 

 work on the former class of relations "are to be mentioned 

 I'erkin's researches on the magnetic ro'atory polaris ition of com- 

 pounds (C. S. Journal, Trans, for 1884, 'p. 421 et sea.) ; and 

 Schiff's researches on the coefficients of capillarity of liquid 

 carbon compounds (Antialen, cexxiii. 47). The investigations of 

 Raoult on the connections between the freezing-points of solu- 

 tions and the distribution of the salts therein form an im- 

 portant contribution to the study of the second group of rela- 

 tions (see especially Ann. dim. Phys. (6), ii. p. 66, et sea.). 

 Perkin has measured the rotations of the plane of polarisation 

 of a ray of monochromatic (sodium) light, produced by passing 

 the ray through columns of various liquid carbon compounds 

 placed between the poles of a large electro-magnet. Then, by 

 the use of the formula r * , where r- observed rotation, 



(I - density, and M = molecular weight (as gas), of the given 

 compound, he has calculated the magnetic rotatory effect of 

 unit-length of the liquid obtained by condensing unit-length of 

 the vapour of the same liquid. The observed results are thus 

 referred to lengths of liquid related to each other in the ratio of 

 the molecular weights of the various compounds examined. 



Each result is divided by the number obtained, by the same 

 method, for water, and the quotient represents the molecular 

 rotatcry power of the given compound. The molecular rotatory 

 powers of a great many compounds belonging to twenty-six 

 series have been determined, and the results show that the 

 constant in question is closely connected with the valencies 

 of the atoms, and with the distribution of the interatomic 

 actions, in the molecules of the compounds examined. Schiff 

 has made an extended series of determinations of the co- 

 efficit nls of capillarity, that is the capillary elevations in tubes 

 1 mm. radius, of many liquid carbon compounds. By multiplying 

 this constant by the density of the compound, and dividing by 

 2, another constant is obtained which represents the weight of 

 liquid raised by capillary action through unit-length of the line 

 of contact between the liquid and the containing vessel. Lastly, 

 by dividing the coefficient of capillarity by twice the "molecular 



„„i„_- » /„• . molecular weight of gas \ . . , . . , 



\olume I i.e. , : -& — r — =_ I, a quotient is obtained 



\ density of liquid ' 



which represents the relative number of molecules raised along 

 the line of contact between the liquid and solid surfaces. 

 Schiffs results, although very numerous, do not yet allow very 

 definite conclusions to be drawn regarding the connection 

 between the three constants and the molecular structure 

 of the compounds examined ; but that a definite connec- 

 tion exists is rendered very probable by these investigations. 

 Raoult has made many determinations of the molecular 

 low. ri 11 r 0/ the freezing-point — that is, the lowering of the freezing- 

 point produced by the solution of 1 gramme molecule of sub- 

 stance dissolved — of various solvents by acids, bases, and salts. 

 The solvents employed were water, benzene, nitro-benzene, 

 ethylene dibromide, acetic and formic acids. In each case the 

 molecular lowering of the freezing-point is approximately equal 

 to one of two values, of which one is double the other. The 

 acids examined may be divided into two groups as regards their 

 effect on lowering the freezing-point of water. The value of the 

 constant measured by Raoult is approximately 40 for one of 

 the groups, and 20 for the other group. The bases examined 

 likewise fall into two groups ; the mean values of the constants 

 being 39 and 19 respectively. Raoult states that the acids with 

 the higher value (40) almost completely displace the acids with 

 the lower value (20) from their combinations with bases, when 

 the acids and salts react in equivalent quantities. The bases of 

 the first group almost completely displace those of the second 

 from their combinations with acids. Measurements of the mole- 

 cular lowering of the freezing-point of water by the action of 

 acids, bases, and salts, present us with data from which, accord- 

 ing to Raoult, the distribution of the various acids, &c, in a 

 changing chemical system may be deduced. 



AMERICAN ORNITHOLOGISTS' UNION 

 "THE second annual meeting of the American Ornithologists' 

 Union was held in the American Museum of Natural His- 

 tory, New York City, September 30 to October 2, 1884, the 

 President, Mr. J. A. Allen, in the chair. 



The Active Members present were : J. A. Allen, H. B. 

 Bailey, Chas. F. Batchelder, Eugene P. Bicknell, William 

 Brewster, Montague Chamberlain, Dr. Elliott Coues, D. G. 

 Elliot, Dr. A. K. Fisher, Col. N. S. Goss, Dr. J. B. Holder, 

 Dr. C. Hart Merriam, Robert Ridgway, Thomas S. Roberts, 

 John H. Sage, George B. Sennett, Dr. Leonhard Stejneger. 



Dr. Philip Lutley Sclater, Mr. Howard Saunders, and the 

 Rev. E. P. Knubley, of the British Ornithologists' Union, were 

 also present, and were cordially invited to take part in the 

 proceedings of the Union. 



The Associate Members in attendance were William Dutcher, 

 Fred T. Jencks, and Dr. Howard Jones. 



On the recommendation of the Council the following persons 

 were elected to Foreign Membership : — Heinrich Giitke, Heli- 

 goland ; Dr. W. Taczanowski, Russia ; Henry Seebohm, 

 England ; Howard Saunders, England ; Dr. H. Burmeister, 

 Brazil. 



The following among others were elected Corresponding 

 Members:— Dr. John Anderson, F.R.S., India; W. T. Blan- 

 ford, F.R.S., London; Major H. W. Feilden, London; Dr. 

 Hans Gadow, England ; Col. H. H. Godwin- Austen, London ; 

 Dr. Julius von Haast, New Zealand ; Dr. E. Holub, Austria ; 

 Dr. C. F. Homeyer, Germany ; E. L. Layard, New Caledonia ; 

 Dr. A. B. Meyer, Germany ; Dr. A. von Mojsisovics, Gratz ; 

 Dr. A. J. Malmgren, Finland, Dr. A. von Middendorff, 



