226 



KNOWLEDGE. 



[October, 1901. 



not only offered a good horizon in almost every direction, 

 but was the chief residential district of the island, and 

 as it still is, the most fertile. But in 1867 there was a 

 virulent outbreak of malaria, and before the Observatory 

 was completed, it had become endemic in Pample- 

 mousses, and the European population had been driven 

 away and forced to seek refuge in the higher country 

 on the further side of the capital, and the gateways of 

 old country houses and widesprcading yet crowded 

 cemeteries alone remain to testifv to the former popu- 

 larity of the district. 



The chief purpose of the observatory was. of course, 

 meteorological; the study of the laws of storms, and the 

 prediction of cyclones, the chief items in its programme. 

 But astronomy was not neglected, and it was furnished 

 with three instraments of respectable size and quality. 

 These were a transit instrument of 3-inches aperture, 

 an equatorial of 6-inches, and a photoheliogi-aph of 

 4-inchos. The existence of an obsei-vatory of this size 

 and situated close to the very centre of the shadow 

 track was a circumstance that could not be overlooked 

 in the choice of stations from whence to observe the 

 eclipse. 



There was a yet further reason why the Astronomer 

 Royal should have selected the Royal Alfred 

 Observatory, Mauritius, as one of the stations to be 

 occupied by one of the eclipse expeditions which he was 

 sending out. The Du-ector, Mr. T. F. Claxton, f.r.a.s., 

 and his chief assistant, Mr. A. Walter, were both former 

 membei-s of the staff of the Royal Observatoi-y, 

 Greenwich, and an intimate connection has been kept 

 up between the two obsei"vatories for the last seventeen 

 years, in that the photogi-aphs of the sun taken at 

 Mauritius, so far as they are required for the completion 

 of the Greenwich series, are regularly sent to the latter 

 obsei-vatoiy for measurement and reduction. 



In coming to Mauritius, therefore, we came to friends 

 and colleagues, who welcomed us as such, and who 



Fio. 2. — Mr. Cluxton's Stiiiion iit the Ei-lipsc. showing tlio 

 !M:inritins Photoliolio|Trapli and the Rapid Ri'ctilinear Caimn-a 

 imiuntcd horizontally in t-onneetion with the 16-incli C'a>lo.stat. 



spared no trouble or pains to secure the success of our 

 work. Wo reached the island on Saturday, April 20, 

 and on the following Wednesday took up our residence 

 at the Observatory, not without many warnings fiom 

 Government officials medical men and friends that we 

 were doing a very risky thing. It was a I'isk, however, 

 that we were obliged to face. We were bound to use 



to the uttermost the advantages offered by the instru- 

 ments and buildings of the Observatory, so that we were 

 precluded from seeking an eclipse station elsewhei-e in 

 the island ; and we could not make the Observatory 

 our station unless it was to be also for the most part 

 our home. For from the Observatory to the healthy 

 country on the central plain of the island is a journey 

 of more than two hours' length by rgad and rail, and 

 the trains only run during the hours of daylight. If 

 we had lived away from the Observatory, therefore, our 

 working hours would have been very short, and it would 

 have been impossible to make use of the stars for 

 focussing and other adjustments of our instruments. 

 We were not at all inclined to regret this necessitv 



1 il .;. '.li- Mauuiler's, Station at the Eelipsp, showino; the 

 Grreenwich Coronagraph and the Evershed Prismatic Camera 

 mounted in connection with the 12-inch Ocelostat. 



at first. The Observatory is a handsome building, 

 standing in eleven acres of its own ground, and its sur- 

 roundings are very pleasant to the eye. The climate 

 was hot, damp and somewhat enervating, but being 

 tempered by the breeze which sprang up every day soon 

 after noon, was far from being unpleasant. A more 

 serious drawback lay in the difficulty of getting sufficient 

 manual assistance, though this was partly overcome by 

 the kindness of the military authorities, who allowed 

 live non-commissioned officers from the gan-ison who 

 liad volunteered for this work to come down for one 

 day to unpack our instruments, and nine to assist us 

 in the observations on the day of the eclipse. A yet 

 further, and most important help was that one of these 

 — Staff-Sergt. Ralph Smith, a.o.c. — was allowed to place 

 his services at our disposal pretty nearly continuously 

 for the three weeks preceding the eclipse, and to his 

 skilful hands we confided the care and treatment of the 

 driving clocks of our telescopes and ccelostats. 



The programme which Mr. Claxton and myself pro- 

 posed to can-y out in combination, comprised the photo- 

 graphing the corona with three instruments, all of the 

 same aperture, but of vei-y different construction and 

 size of image, so as to secure delineations as perfectly 

 as possible of its three chief regions. The photo- 

 heliograph of the Mauritius Observatory was the first 

 of these, and gave an image of the sun nearly eight 

 inches in diameter. With this instrument only the 

 prominences and the very lowest region of the corona 

 could bo obtained. Next came the Greenwich corona- 

 graph, giving an image 2j-inchcs in diameter. With 



