Like the June 2012 transit of Venus, the December 1874 transit was visible in its entirety from Australia. The observatories at Sydney, Melbourne and Adelaide, which are the capitals of the three main states or colonies at the time, made plans to ensure that the rare event was well observed. In addition, there were two United States observing teams in the island state of Tasmania.
In subsequent posts I will discuss the plans and activities at the different places. Here I would like to introduce you to the magnificent book published by Henry Chamberlain Russell, the director of Sydney Observatory, about the 1874 transit observations in 1892. Images from this book are used in almost every book or article published in recent times on the transit. Disappointingly, the images are often not credited or wrongly credited to Charles Potter, the Government Printer, whose name is prominent on the front cover of the book.
In preparation for the transit Russell obtained new instruments including a 29-cm or 11½ -inch refractor or lens telescope from Hugo Schroeder of Hamburg, Germany that is still one of the treasures of Sydney Observatory. He also arranged for three observing stations at country sites to maximise the possibility of obtaining observations if the weather was poor. To staff these extra stations he recruited best scientific men in the Colony including Archibald Liversidge, the newly appointed professor of geology at the local university.
Immediately after the transit Russell requested all the observers to submit written reports as well as illustrations of their observations. He intended to publish these results as soon as practicable, writing to the Under Secretary of Finance and Trade on 30 January 1875:
“The results obtained in New South Wales during the recent Transit of Venus are of the greatest importance, both in a scientific point of view, and also with regard to the credit due to this Colony for the position taken in this important scientific matter.
In order to make the results generally known they must be printed in a first class style, reproducing in the book all drawings photographs &c so far as possible. If this is properly done the work will become known all over the scientific world, and great credit will accrue to this Colony.”
Russell goes on to explain that his absence overseas (to report in person to the Astronomer Royal at Greenwich) would not cause undue delay as, in any case, the lithographs would take six months to produce. In the event it took 18 years for the book to be published. Why the long delay? I think that it was the fault of the Government Printer and the manuscript had languished with the printer for most of the 18 years. When I found the originals of the book and its illustrations in the Observatory archives there was a note with them from Russell saying to the printer that the book has been delayed for long enough and to please get on with publishing it.
In the next post we will look at a few of the illustrations from the book and discuss why recently they have been found to provide useful information about the atmosphere of Venus. We will also consider the controversy surrounding a significant omission from the book.