354 Mr. William. J. S. Lorlcypr [March 1. 



Now, the case is different with the prismatic camera, a form of 

 instrament first used visually in the eclipse of 1<S71 and photographic- 

 ally in 1.S75. In place of the individual monochromatic images of 

 the slit, monochromatic images of the whole object itself take their 

 place. While the degree of accuracy in the measurements of the 

 wave-lengths is somewhat less than in the slit form, the great advan- 

 tage gained is that the form of the object photographed is given. 



Thus in the case of the application of this instrument to eclipse 

 work, it is possible to determine and differentiate between the 

 cliemistry of the chromosphere and corona ; to measure the depths of 

 the cliromospheric layers ; to locate the regions of strongest coronal 

 radiations, besides securing the forms, positions, and composition of 

 each prominence if such data were desired. 



It will thus l)e seen that the use of both kinds of instrument is 

 very desirable for eclipse work, as they supplement each other with 

 regard to the results that can be derived from them. 



For the observation of the eclipse of last year, two official and one 

 private party proceeded from England ; Australia was represented by 

 a large party of observers, under the leadership of Professor Baracchi, 

 and two other observers went out separately. 



One of the British official parties consisted of Father Cortie, S. J., 

 and Brother McKeon, representing the Eclipse Committee of the 

 Royal and Royal Astronomical Societies, and the other was composed 

 of myself representing the Solar Physics Observatory of the Board of 

 Education. These parties left England on February 8, by the Orient 

 Liner s.s. " Otway." I had previously made arrangements that Mr. 

 Frank McClean should join me as a volunteer assistant, and he 

 boarded the " Otway " at Marseilles. It was through him that other 

 valuable volunteers in the persons of Mr. John Brooks of Sydney, 

 Mr. Henry Winkelmann of Auckland and Mr. Raymond of the vSydney 

 Observatory were secured, and I was fortunate on my way to Australia 

 to obtain additional volunteer help in the form of Mr. R. C. Ander- 

 son, of Southaaipton. 



Some time before leaving England we had been informed that 

 the Admiralty had placed H.M.S. " Encounter," of the Australian 

 Squadron, at the service of both the Official British parties, to take us 

 to Vavau, assist us with our observations, and return with us to 

 Sydney. In our preparations, therefore, a considerable increase was 

 made in the instrumental outfit, because experience has taught us 

 that a much greater programme of work can be attempted when we 

 have such skilled assistance as is afforded by the officers and men 

 of a man-of-war. 



On our arrival at Sydney, on March 16, we at once put ourselves 

 in communication with Captain Colomb, of H.M.S. " Encounter," and 

 made all the necessary arrangements with him. Sydney was left on 

 March 25, and on the 2343 mile run to Vavau, volunteers were called 

 for from the ship's officers and men, and more than enough sent in 



