. The transit of Venus. l method of observation is De llsles,aided everywhere when possible by all the othermethods except the heliometric. From the account that has been given of the diffi-culty of determining the longitudes of the differentstations it will be seen that no little power oforganisation is required for the execution of the fore-going programme. All preparations must be madefor the observation of the moon and moon must be made, and also actually inventedfor the express purpose. More than seventy chro-nometers must be provided, and negotiations must becompl
. The transit of Venus. l method of observation is De llsles,aided everywhere when possible by all the othermethods except the heliometric. From the account that has been given of the diffi-culty of determining the longitudes of the differentstations it will be seen that no little power oforganisation is required for the execution of the fore-going programme. All preparations must be madefor the observation of the moon and moon must be made, and also actually inventedfor the express purpose. More than seventy chro-nometers must be provided, and negotiations must becompleted with telegraph companies. The photo-graphic operations have required the invention of anew photo-heliograph, and the Janssen method of anew application to it. The observations of contacthave required the purchase of a large number of VI.] THE TRANSIT OF VENUS. equatorials ; for each station, besides having a 6-inchtelescope, has also one or more smaller of the larger ones, made by Simms, is shown in. ^mmm^smm , ? ;•, \v-yw M ,\ \Fig. 20.—6-Inch Equatorial of the British Expedition. Fig. 20. The transit instruments have also been madeexpressly for this expedition. Besides this all the G THE TRANSIT OF VENUS. [chap. accessories of these instruments had to be for receiving them had to be made. Forms forentering and reducing the observations had to beprepared and printed. For some of the stationssleeping arrangements, cooking apparatus, washingutensils, and provisions had to be provided. Work-men, masons, and assistant photographers, besidestwenty-two observers, had to be collected and trainedto the work. When this is considered it will be seenthat no ordinary man could fulfil all the we have in our Astronomer Royal a manwho combines to an exceptional degree theoretical,mechanical, and organising powers; and we maysafely say that the present expedition has been com-pleted under a generalship quite unparalleled in theannals o
Size: 1463px × 1707px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, bookidtransitofven, bookyear1874
