Feb. 14, 18 78 J 



NATURE 



311 



was required for the Pi-ho river, which intersects the line. The 

 apparatus used are Morse's die-writers worked by Leclanche 

 elements. Mr. Betts and some of his assistant pupils have been 

 invited to visit Formosa in order to construct a line on the west 

 coast of this island, viz., between Kee Lung and Tay-wan-foo. 

 It is also proposed to establish another line >t Tian Tsin, con- 

 necting that city with the capital of the province Paou-ting-foo. 



During the year 1877 the Parisian press numbered no less 

 than 836 different newspapers and serials (against 754 in 1875). 

 Of these, 51 daily and 14 weekly papers are political, 49 serials 

 are theological (37 Catholic, 10 Protestant, and 2 Israelitic) ; 

 66 are dedicated to law, 85 to political economy, 20 to geo- 

 graphy, 74 to belles lettres ; 20 are pedagogic, 52 literary- 

 scientific, 56 artistic, 68 treat of fashions, 77 of technology,! 75 

 of medicine ; the contents of 43 are mathematical and natural- 

 scientific, of 22 military, of 3 1 agricultural. Besides the above 

 there are 16 sporting papers, 13 of various contents, and 4 dedi- 

 cated to Freemasonry. 



Many alloys of tin and other soft metals hardened by addition 

 of antimony, copper, &c., do not give a clear tone on being 

 struck, but a lead-like, dull one. It has been found by M. 

 Lilliman {Pol. Noiizblatt) that the power of sounding clearly 

 may be imparted to them, by immersing them for a half to one 

 minute in a paraffin or oil bath, heated to a temperature 5° to 

 5° "5 below the boiling-point, then taking out and allowing to 

 cool. This does not produce any diminution of density, but a 

 considerable increase of the hardness and rigidity. 



The Proceedings of the Bristol Naturalists' Society (vol. ii. 

 part I, new series) contains, as usual, some papers of more than 

 average value. There are three papers on the microscope by 

 Dr. Fripp, two on the Bristol coalfield by Mr. W. W. Stoddart, 

 besides two other geological papers by the same author, a paper 

 by Mr, W. Evans on the scientific aspects of tannings and other 

 matters of importance. 'YXvi Transactions ol the Bedfordshire 

 Natural History Society for 1876-7 contains a number of good 

 papers on local natural history. 



The gasworks at the Grasbrook at Hamburg have recently 

 been covered with a gigantic iron roof, constructed by the 

 " Essener Union." Its weight is 51,500 kilogrammes, its length 

 84 metres. With the exception of the roof on the Liverpool 

 gasworks, it is the largest in Europe. 



At the meeting of the Royal Academy of Sciences at Berlin, 

 on January 24, Prof. Du Bois Reymond, as President of the 

 Committee of the Humboldt Institution for Naturalists and 

 Travellers, read a detailed report of the activity of this institu- 

 tion during the past year. The first undertaking was that of 

 Herr J. M. Hildebrandt, and referred to the exploration [of the 

 enow-clad mountains of Equatorial Africa, viz., of the Mt. 

 Kenia and of the Kilima-Ndjaro. The [well-known traveller, 

 although he approached the former mountain to within a few 

 days' march, could not reach it altogether on account of the 

 unconquerable difficulties placed in his way by the enmity of 

 the native tribes, but he will again take up his plan after having 

 recruited his health at home. Herr Hildebrandt, however, has 

 brought home rich scientific collections from his journey, and 

 has presented them to the scientific societies at Berlin ; his geo- 

 logical collections are of special interest. The second traveller 

 sent out by the Humboldt Institution, Dr. Karl Sachs, continued 

 and terminated his investigations on the electric eels {Gymnotus 

 tlectricns) at Calabozo, an important town in the Llanos of 

 Venezuela. He succeeded in adding to our knowledge of Gymnotus 

 considerably, so that of this species now quite as much is known 

 as of Torpedo ; he failed, however, to throw any light upon 

 the development of Gymnotus, Dr. Sachs is now^ occupied in 



writing a treatise on this subject, as well as a description of the 

 country and the people of Venezuela and his [own experiences 

 while travelling. 



It is very unsatisfactory to hear that the consignment of soles 

 and turbot which left the Southport Aquarium on January 3 for 

 the purpose of stocking the Bay of Massachussetts has turned 

 out almost a total failure, one pair of the former only having 

 arrived at their destination in safety. Prof. Baird, United 

 States Commissioner of Fish and Fisheries, is so anxious to in- 

 troduce the above-named fishes into American waters that 

 another journey to^England is contemplated about May next. 

 Much experience has been gained in the transit of live fish 

 across the Atlantic, which will be of considerable importance 

 in facilitating future arrangements. It is highly probable that 

 the bony pike and other American fishes, many of which are 

 remarkable for their brilliancy of colour, will ere long find a 

 home in English aquaria. 



The additions to the Zoological Society's Gardens during the 

 past week include a Common Swan {Cygnus olor) from Holland, 

 presented by Mr. John Colam, F.Z.S. ; two Crested Guinea 

 Fowls {Nuinida crisiata) from West Africa, presented by Mr. 

 Collingwood ; two Canadian Geese {Bernicla canadensis) from 

 North America, presented by Mr. Edward J. Philpot ; four 

 Reeves's Terrapins {Clemmys reevesi) from China, presented by 

 Mr. A. Thomson ; a Brazilian Tortoise ( Testudo tabulatd) from 

 Cartagena, presented by Capt. King ; a Poitou Donkey (Asinus 

 vulgaris) from the south of France, deposited ; an Azara's Fox 

 {Canis azarcc) from South America, purchased. 



HARRESrS SPECTROSCOPICAL 

 RESEARCHES 



T^/'HEN the late Prof, d' Arrest was called to superintend the 

 * * building of the new observatory in Copenhagen and the 

 erection of a large refractor (16 feet focal length by 11 inches 

 aperture), he took advantage of the opportunity thus offered to 

 enter into more extensive researches on the nebulie, than he had 

 been able to undertake at Leipzig. He intended at first to 

 observe all the nebulae which were visible in his refractor, but he 

 soon found that a work beyond human power, and that in fact 

 the nebulae are infinite in number. Working hard for six years 

 he was only able to collect the eighth part of the observations 

 required for laying down approximate positions of all those 

 nebulae which are distinctly visible in the ^Copenhagen refractor, 

 and whose places could be exactly determined. These observa- 

 tions were published as *' Siderum nebulosonim observationes 

 Havnienses," in 1867, for which the gold medal of the Royal 

 Astronomical Society was awarded to him in 1875. Prof. 

 d'Arrest died eight years after the publication of his great work, 

 his health broken down by constant night-watches. These years 

 were spent mostly on spectroscopical researches, which were 

 partly published in the Astronomische Nachrichlen, partly in a 

 separate paper, " Undersogelser over de nebulose Stjerner i 

 Henseende til deres spectralanalytiske Egenskaber," in 1872. 

 This latter paper does not appear to be so widely known as it 

 deserves, and an abstract in the columns of Nature might 

 therefore be acceptable to many. 



It took D'Arrest several years to get sufficiently acquainted 

 with the use of the new apparatus — so different from those usually 

 handled by astronomers of the old school. Various forms o' 

 spectroscopes are employed according to the subject to bi 

 examined. To observe the protuberances or their lines the 

 greatest possible dispersion is required in order to weaken on one 

 hand the sun's light, and on the other hand the- diffuse atmo- 

 spherical light which forms the background on which the lines are 

 projected ; while prisms of small dispersive power are employed 

 when for instance the bright lines of comets or nebulae are 

 examined. D' Arrest's spectroscope was not intended for any 

 extreme application ; it was a so-called Janssen's, after Amici's 

 principle composed a vision directe of three crown and two flint- 

 glass prisms from Merz. 



The solar light has lately been made to go twice through 

 the system of prisms, and the dispersive power thus doubled 

 has rendered many more bright lines visible than were known 



