As the transit of Venus of 1874 approached, prepara tions were set on foot by the German Government in good time; a commission of the most celebrated astronomers was appointed, and it was resolved that the heliometer should be the instrument chiefly relied on.
His discussion of the effects of parallax in the transit of a planet over the sun's disc excited great interest, having appeared (in 1764) between the dates of the two transits of Venus that took place in the 18th century.
Saturn for lead, Venus for copper, and Mars for iron, and the belief that the colours of flowers ' The Egyptians believed that the medicinal virtues of plants were due to the spirits who dwelt within them.
After he had observed the transit of Venus at Tahiti, he circumnavigated New Zealand and went in search of the eastern coast of the great continent whose western shores had long been known to the Dutch.
The failure of the method based on transits of Venus led to an international effort carried out on the initiative of Sir David Gill to measure the parallax by observations on those minor planets which approach nearest the earth.
He also vigorously criticized the official arrangements for observing the transits of Venus of 1874 and 1882.
Other Italian cults introduced at this period were those of Juno Sospes and Juno Regina, Venus and Fortuna Primigenia, a goddess of childbirth who came from Praeneste.
In the preceding century reliance was placed entirely on the observed moments at which Venus entered upon or left the limb of the sun, but in 1874 it was possible to determine the relative positions of Venus and the sun during the whole course of the transit.
Towards the close of the Franco-Prussian War he made an admirable defence of Brest, and his organization of the French expedition to the island of St Paul to observe the transit of Venus in 1874 obtained his election to the Academy of Sciences and his promotion as commander of the Legion of Honour.
The similarity of name and the fact that Venus Lubentia had a sanctuary in the grove of Libitina favoured this idea.