The First Series of Light Science Essays met with a success so far beyond my expectations, that I should have found in that circumstance alone a reason for adding the present volume to the series. But I have also felt a wish to publish these essays because they contain facts collected at the cost of much labour and carefully discussed,useful, therefore, I trust, to others as well as to myself, when thus gathered into a volume.
Those who have read my former series of essays, viz., ' Light Science, Series I.,' 'The Orbs around Us,' and 'Essays on Astronomy,' will perceive that even when I treat here of subjects already dealt with by me elsewhere, I have been careful to avoid the repetition of any statements, except those few without which a subject would be incomplete. For instance, it will not be easy to find in my two papers on comets in ' The Orbs around Us,' statements or reasoning repeated in the two papers on comets in the present volume.
However, for the most part, the papers in this series are distinct in subject as well as in treatment from any of my essays which have formerly appeared.
I invite special attention to the second essay on the Transit of Venus. The time is drawing near when it will be too late to take action to extend and render complete and satisfactory our preparations for this important phenomenon - the most important, I venture to assert, of all the astronomical phenomena of the present century. Without imputing blame to any person, I must dwell strongly on the fact that the share proposed to be taken by Great Britain in the observations of the transit, is unworthy of her position in the scientific world, and as a nation. There is great risk that, for want of an adequate number of southern stations, the whole series of observations by all countries engaged in the work will result in failure; and it appears to me -nay, more positively-it certainly is a deplorable circumstance, that while Russia and America are providing for more than thirty northern stations, whereof sixteen are Halleyan, Great Britain will supply but three southern stations, of which only one chances to be Halleyan as well as Delislean; while even as respects this one station, Mr. Goschen has told the country, speaking in his place in Parliament, that either Halley's method 'will not be applied at all, or at least very little reliance will be placed upon it.' Yet at sixteen northern stations, some of them most difficult of occupation, Russia and America will apply this very method; while even the criterion devised to minimise the value of the method, leaves it superior, when applied at the stations I have indicated, to De-lisle's, as applied at selected stations.
I appeal to all who have influence in these matters to examine the evidence for themselves (whether as presented here, or with charts in my Essays in Astronomy, or in recent numbers of the Monthly Notices of the Astronomical Society), and to form their own judgment as to the position of affairs. That is all I ask, since I am satisfied that that will be altogether sufficient to suggest the promptest and most energetic action.*
Richd. A. Proctor.
London: May 1873.
* Since this was written I have received letters from the greatest master of mathematical astronomy this country has produced since Newton's day, strongly confirming my views as to the extreme importance of providing many southern stations for applying Halley's method in 1874, and urging me, moreover, to appeal to America to take part in this special work, for which she is peculiarly fitted, because of the bravery and enterprise of her seamen, the skill and ingenuity of her astronomers and physicists, and her singular liberality as a nation in all scientific matters.