210 



NA TURE 



\June 27, 1889 



"bination proved in his hands very successful, though his gal- 

 ■vanomeler was not the mjst sensitive possible, since it was a 

 matter of importance that the needle should quickly come_ to 

 rest. As actually adjusted, the galvanometer gave a deflection 

 ■of one scale division for o'ododooo; ampere, the period being 

 10 seconds. 



The two principal points to which attention was directed were 

 the comparative intensity of radiation of the sun and moon and 

 the coefficient of transmission of our atmosphere for lunar 

 radiations. The first point was determined by two methods : 

 in one, but a very small fraction of the sun's rays were suffered 

 to fall on the thermograph ; whilst in the second method a re- 

 sistance was interposed in the galvanometer. The two methods 

 gave very fairly accordant results, the mean giving the solar 

 radiation as 184,560 times the lunar. The experiments on the 

 transmission of the lunar rays through our atmosphere gave a 

 remarkably high value ; for the deduced result showed that 

 89^ per cent, of the rays of the moon when vertical are 

 transmitted by the air at standard pressure. 



Observations on the lunar eclipse of January 28, 1888, agreed 

 with those of Langley and Lord Rosse in their testimony as to 

 'the suddenness with which the heat received from the moon is 

 cut off at totality. 



As to the quality of the lunar rays, it was found that but 

 31 per cent, were transmitted through a plate of quartz which 

 allowed 93 per cent, of the sun's rays to pass. The radiations 

 from a platinum coil placed in a Bunsen flame turned down as 

 low as possible, suffered to about the same extent as the rays 

 •from the moon. From experiments upon the radiating powers of 

 different rocks, a table of which has been formed. Prof. Ilutchins 

 •concludes that a very considerable portion, about half indeed, of 

 the incident rays are absorbed. The surface of the moon should 

 therefore become strongly heated, but the evidence afforded by 

 total lunar eclipses appears to show that scarcely any of this 

 surface heat succeeds in passing through our atmosphere. 



ASTRONOMICAL PHENOMENA FOR THE 

 WEEK 1889 JUNE 2>o—JULY 6. 



/"pOR the reckoning of time the civil day, commencing at 

 ^ •*• Greenwich mean midnight, counting the hours on to 24, 

 is here employed ) 



At Greenwich on June 30 

 Sun rises, 3^. 49:n. ; souths, I2n. 311. 246;.; daily increase 

 of southing, ii'Ss. ; sets, 20^1. 18.11.: right asc. on meridian, 

 6h. 38'4m. ; decl. 23° 10' N. Sidereal Time at Sunset, 

 I4h. 54m. 

 'Moon (at First Quarter on July 6, 6h.) rises, 5h. 35m. ; 

 souths, I3h. 48m. ; sets, 2ih. 54m. : right asc, on meridian, 

 8h. 22-9m. ; decl. 21" 21' N. 



Right asc. and declination 

 Planet. Rises. .Souths. Sets. on meridijn. 



h. m. h. m. h. m. h. m. - / 



Mercury.. 3 14 .. 11 o .. 18 46 ... 5 35'2 .. 18 47 N. 



Venus ... I 28 .. 8 53 .. 16 18 .. 3 27-8 .. 15 19 N. 



Mars ... 3 26 ... II 48 ... 20 10 ... 6 23*2 ... 24 8 N. 



Jupiter ... 19 40 ... 23 34 ... 3 28* .. 18 11-3 ... 23 16 S. 



Saturn ... 7 17 ... 14 48 ... 21 19 ... 9 23-8 ... 16 29 N. 



Uranus... 13 o ... 18 31 ... o 2*... 13 69 ... 6 27 S. 



Neptune., i 43 .. 9 32 ... 17 21 ... 4 67 ... 19 16 N. 



* Indicates that the setting is that of the following morning. 



Variable Stars. 



Star. R.A. Decl. 



h. m. o / h. m. 



U Cephei o 52-5 ... 81 17 N. ... July 4 21 46 w 



U Virgin is 12 45-5 ... 6 10 N. ... June 30, /// 



,Z Virginis 14 4-4 ... 12 47 .S. ... July 6, M 



U Bootis 14 49-2 ... 18 9 N. ... ,, I, m 



S Ophiuchi 16 27-9... 16 56 S. ... ,, i, M 



U Ophiuchi 17 10-9... i 20 N , 2, 3 11 »» 



,, 23 19 ;« 



X Sagittarii 17 40-6 .. 27 47 S. ... June 30, 22 o M 



•July 5, 2 o w 

 W Sagittarii ... 17 57-9 ... 29 35 S. ... " ,, i, o o m 



U Sagittarii 18 25-6... 19 12 S , 2, o o M 



R LyrzE 18 52-0 ... 43 48 N. ... ,, 6, m 



T) Aquilse 19 46-8 ... o 43 N. ... ,, 3, i o »« 



X Cygni 20 39-1 ... 35 11 N. ... ,, 2, 22 o m 



T Vulpeculas ... 20 46*8 ... 27 50 N. ... June 30, 21 o M 



■S Cephei 22 25*1 ... 57 51 N. ... July 6, 22 o m 



M signifies maximum ; rn minimum. 



July. 

 I 

 I 



I ... Mercury stationary. 

 19 ... Saturn in conjunction with and 2° 3' south 



of the Moon. 

 21 ... Sun at greatest distance from the Earth. 



GEOGRAPHICAL NOTES. 



To an unusually crowded meeting of the Royal Geographical 

 Society on Monday night Dr. Frithjof Nansen told in detail the 

 story of his journey across Greenland last summer. We have 

 already given the main incidents of this remarkable journey, and 

 need only refer here to some of the scientific results. These 

 cannot be fully given as yet, as the meteorological and other 

 data collected by Dr. Nansen have not been fully worked 

 out. It should be borne in mind that the main purpose of Dr. 

 Nansen's expedition was to prove that it is quite possible to 

 cross Greenland : in this respect the expedition has been com- 

 pletely successful. Dr. Nansen repudiates as untenable the idea 

 that somewhere in the interior of Greenland an oasis of greenery 

 must exist. The conditions there are quite different from 

 those of Grinnell Land, where the winter's snow is annually 

 melted away over a certain extent of the surface. Greenland, 

 on the contrary, Dr. Nansen maintains, is so thickly covered 

 with the ice-accumulations of ages, that no part of the interior 

 is ever laid bare. He surmises that there is a sort of wind- 

 pole about the high centre of the interior, from which, as a rule, 

 the cold winds radiate in all directions to the warmer coasts. The 

 cold experienced by the expedition reached as low as 90° F. below 

 freezing, and as Dr. Nansen's thermometers were not adapted 

 for a lower temperature he believe? that the temperature was at 

 times much under that. He compares the configuration of the 

 inland ice to a shield, curving upwards from the edges to a sort 

 of plateau, reaching in pa^ts at least 10,000 feet above sea-level. 

 As to the configuration of the ground underneath, Dr. Nansen 

 maintains that it must be similar to Norway and Scotland, with 

 the same rugged mountain masses, high ridges, va'leys,and fjords ; 

 and that the shape of the ice-covering has nothing to do with the 

 shape of the land underneath. The immense accumulation of 

 snow has levelled up everything ; in places the ice must be 6000 

 feet deep, and even the tops of the mountains must be covered with 

 hundreds of feet of glacier. He believes the wind has much to 

 do with maintaining the ice-level, and does not believe that the 

 quantity of snow varies much from year to year. The enormous 

 pressure exercised by this vast mass of ice causes it to send off^ 

 icebergs, and, in Dr. Nansen's opinion, running water helps to 

 maintain the uniform level. Even in winter, he maintains, there 

 are running streams underneath, due to the action of this pressure, 

 and which help to prevent the growth of the mass. From a 

 me'.eorological point of view the scientific exploration of Green- 

 land is in Dr. Nansen's estimation of immense importance. He 

 therefore means to return to the country, probably in the autumn 

 of next year. He will land on the east coast, much further 

 north than his last year's starting-point. He will endeavour to 

 explore the east and north coasts, and will attempt to cross the 

 continent at its broadest part. 



In illustration of Dr. Nansen's paper a large collection of oil 

 paintinjjs of Greenland scenery was exhibited, by a Danish 

 artist, Mr. Carstensen, who spent two suaimers and autumns 

 travelling up and down the west coast. They show, better than 

 any photographs, the wonderful colour of the Greenland land- 

 scapes, the extent and nature of the ice, and the beauty and 

 richness of the vegetation during the short summer of this 

 ice-bound land. 



THE LADIES' CONVERSAZIONE OF THE 

 ROYAL SOCIETY. 



HTHE Ladies' Conversazione of the Royal Society, given 



June 19, was a great success. The following were aaioi! 

 the objects exhibited : — 



Exhibited by Miss Constance F, Gordon Gumming : 

 Sketches near the active volcano of Manna Loa, on the Isls 

 of Hawaii, and the extinct crater of Haleakala, on Isle Man 

 described in " Fire Fountains of Hawaii." 

 ^Exhibited by Prof. Silvanus P. Thompson: — (i) Acousfi 

 apparatus illustrating polarization of light. (2) Magnetic rofi' 

 tion of plane of polarization shown by projecting a polariz<| 

 beam through a bar of heavy glass, and analyzing by a 24-rd 



