I04 



NATURE 



[May 31, 1900 



thermometers fall at different rates. Observations made simul- 

 taneously on them every minute, and plotted on squared paper, 

 illustrate' fairly well KirchhofPs law enunciating that a body 

 emits those rays best which it absorbs best. When the gas 

 flame is replaced by a freezing mixture, the greatest fall of 

 temperature is experienced by the blackened thermometer, and 

 the least by the silvered one, for the same reasons. 



The same arrangement of thermometers may be used to show 

 the cold produced by evaporation. For this purpose, the bulb 

 to be blackened has to be wetted immediately before starting 

 the radiation experiment. First the temperature of this thermo- 

 meter falls, even though the gas flame be lighted, but after a 

 few minutes its temperature rises very quickly to reach the same 

 state of equilibrium as when taken with dry black paint. In 

 Fig. I the dotted curve represents the behaviour of the freshly 

 wetted blackened thermometer. 



For silvering the thermometer bulbs, we use most success- 

 fully the process described first by A. Martin in Poggendorff' s 

 Amialen (cxx. 1863, P- 335 )> 3-"^ reprinted in many of the 

 books on practical physics. K. T. Fischp;k. 



Miinchen (Bavaria), Kgl. Technische Hochschule. 



THE TOTAL ECLIPSE OF THE SUN. 



THE last total solar eclipse of this century appears to 

 have been successfully observed all along the line 

 of totality. The weather conditions were favourable at 

 all the observing stations, and numerous photographic 

 and visual observations have been made of the pheno- 

 mena revealed during a total eclipse. Elaborate arrange- 

 ments were made to study the eclipse in all its aspects, 

 and it has fortunately been possible to carry them out 

 in a most satisfactory manner. 



A code telegram received at the Solar Physics 

 Observatory, South Kensington, from Sir Norman 

 Lockyer, states : — " At the time of the eclipse the 

 weather was excellent, and all the instruments were 

 satisfactorily employed. There was a fall in temperature 

 during the eclipse of from 4^ to 6^ C. The eclipse was 

 not a dark one, and very few stars were seen. The corona 

 exhibited large equatorial extensions and distinct polar 

 tracery as expected. Observations of the shadow band 

 were fully made in two planes. In the fixing up of the 

 instruments, and the mkking of the observations, assist- 

 ance was given by about 1 50 of the ofificers and crew of 

 H.M.S. Theseus, which conveyed the eclipse party from 

 Gibraltar to Santa Pola, a i&^ miles south-west of 

 Alicante." 



The corona was similar to those observed during the 

 eclipses of 1878 and 1889— both epochs of sunspot mini- 

 mum — and thus supplies additional support to the prob- 

 ability of a real connection between the coronal structure 

 and the state of solar activity. There were two long 

 equatorial streamers, the western one being bifurcated 

 and extending about two solar diameters. Several ob- 

 servers note that the inner corona was visible for at 

 \&z.%\five seconds after totality. 



The eclipse was a short, and therefore a bright, one, 

 which accounts for the general report that no shadow 

 was seen either on land or in the atmosphere, and that 

 very few stars were visible. Mercury and Venus were, 

 however, observed. All the reports agree in estimating 

 the duration of totality as shorter than was expected, so 

 that the lunar tables will need slight revision for future 

 computations. 



Important observations were made of the shadow 

 bands, which are stated to be very different in many 

 respects from those previously observed. From one of 

 the American stations it is reported that the bands were 

 about one inch in breadth, their general direction being 

 south 56^^ E. ; before totality their motion was at right 

 angles to this — that is, almost north-east ; and in the 

 opposite direction after totality. Superposed on the 

 linear bands, however, were certain dark patches pre- 



NO. 1596, VOL. 62] 



viously unnoticed, having a motion at right angles to 

 that of the bands. Baily's beads were well seen at the 

 instants of second and third contact. 



Prof. Todd, at Tripoli, is reported to have successfully 

 employed twenty photographic cameras, one of which 

 was furnished with a lens of 24 inches aperture. 



The party at Pinehurst, from the U.S. Naval Obser- 

 vatory, under Prof. Skmner, obtained a good series of 

 spectrum photographs, including five with plane and 

 concave gratings and four with an objective prism ; also 

 five large scale photographs of the corona with a 

 lens of forty feet focus.. 



Prof. Pickering obtained a good series of photographs 

 with the new large instrument he had specially made for 

 searching for an intra-Mercurial planet. 



As we go to press, the following description of the 

 observing parties at Santa Pola has been received from 

 Sir Norman Lockyer. 



Preparations at Santa Pola. 



Santa Pola, Friday, May 25. 



The party from the Solar Physics Observatory arrived 

 here on May 17, and now, thanks to the assistance so 

 freely rendered by the Spanish authorities of all grades, 

 and the strong working parties furnished by H.M.S. 

 Theseus, the instruments are all in order and we are ready 

 for the eclipse. 



At Gibraltar the Captain of the Theseus sent ofif Mr. 

 Daniels, torpedo gunner, to meet the Expedition, and the 

 sixty-nine cases of instruments were carefully transferred 

 to a lighter, and so soon as they were landed here those 

 belonging to each instrument were at once brought 

 alongside the piers which had already been erected for 

 them on a site as near the landing stage as possible, 

 thanks to the diligence of Mr. Howard Payn, a volunteer 

 assistant who had preceded the party by rail and had 

 secured the necessary bricks at Alicante. 



The prismatic cameras, and those of the ordinary 

 kind, fed by coelostats and siderostats, with all prisms 

 and mirrors, were in adjustment by the 21st, and drills 

 were begun on the 22nd. 



The parties of observers are as follows'; and careful 

 notes of the arrangements made are being kept, as some 

 improvements have been made on those adopted in 1898. 



Parties on Shore. — Prismatic cameras, (i) One prism 

 (20 ft.); (2) two prisms (7 ft. 6 in.). Coronagraphs. 

 (3) Graham (f. 6-5) ; (4) Dallmeyer (f. S'o about) ; (5) De 

 la Rue (f. 17-5) ; (6) long focus (f. 48). (7) Discs. (8) 

 Shadow bands. (9) Meteorology. (10) Stars. (11) 

 Landscape colours. 



Parties on Board.— { i ) Stars. (2) Shadow. (3) Meteor- 

 ology. (4) Landscape. 



The whole party is in robust health, thanks to the 

 glorious climate and any amount of work in the open 

 air. We live in a little inn, which since the Queen's 

 birthday has blossomed into the " Victoria Hotel," kept 

 by one Frasquito Dols, a Spanish sailor and sea-cook, a 

 regular "handy man," who has put up mosquito curtains, 

 and rigged up a lift to carry our well-cooked food and 

 excellent local wine to the first floor where we reside ; 

 in rooms which, though furnished with unparalleled sim- 

 plicity, are absolutely clean. It seems a pity that more 

 do not know of this delightful climate so near home, in 

 which the winter months may be so pleasantly spent in 

 the shadow of date palms. 



The ship is much further away from the shore than 

 in 1898— some 2000 yards — and the winds rise very sud- 

 denly in the open roadstead. The administration of the 

 camp, therefore, devolves upon Lieut. tDoughty, R.N., 

 who, with Lieuts. Andrews and Patrick, remain constantly 

 on shore in a pile-dwelling— a bathing establishment 

 which has seen better days, and has been rechristened 

 " Theseus Villa." 



The " Scotch Commission," as it is called here— that is, 



