HaasT.— Address. 89 
was able to offer further evidence in confirmation. This statement appeared 
so important, that Le Verrier went himself to Orgéres, and, after examining 
most carefully the somewhat primitive modes of Lescarbault as to fixing his 
time and of making his calculations, the great Paris astronomer was convinced 
of the correctness and importance of the discovery made, and he calculated, 
from the data given, the approximate elements, of which the following are 
given in George F. Chambers’, F.R.A.8., ‘Descriptive Astronomy :"—** The 
inelination of the orbit to the ecliptie, 12? 10'; daily heliocentrie motion, 
18? 6'; distance from sun's centre, taking the earth's as unity, 0.148, or 
about 13,000,000 miles; period, 19d. 17h." The applieation of Kepler's 
third law, namely—that the squares of the periodic times of the planets are 
proportional to the cubes of their mean distances, gives a remarkable 
semblance of truth to Le Verrier's * Elements." On March 20th, 1862, 
Lummis, in Manchester, observed also what he thought was a planet 
passing across the sun's dise, but unfortunately he could only continue his 
observations for twenty minutes, when other duties compelled him to desist. 
There are also several other instances known where astronomers have 
observed a small but well-defined round spot pass over the sun's dise, as, for 
instance, Friteh, October 10, 1802; Stark, October 9, 1819; Sidebotham, 
March 12, 1849; Schmidt, October 11, 1847 ; Decuppis, October 2, 1839; 
which all have been eonnected with Lescarbault's planet, and to which the 
name Vulcan has been provisionally given. The observations of Lummis 
offered the material to two French astronomers for new calculations of the 
elements, the results of which are not contradictory to those published 
by Le Verrier, but appear to confirm them. From the position of the 
nodes, or those points where the orbit is cut by the ecliptic, it appears that 
transits over the sun's dise can only be expected between March 25 and 
April 10 at the descending node, and between September 27 and October 14 
at the ascending node. However, on October 2, 1876, and at a subsequent 
meeting, the French Academy received further communications from Le 
Verrier, in which, with great lucidity, all material at his command was 
most carefully revised, and the elements of the new planet were given, the 
existence of which the French astronomer believes to have been proved. 
Le Verrier shows that many solutions can be given according to the 
value given to an indeterminate in the formula. Several calculations are 
then offered which, with a possible indeterminate, range from 27.96 to 51.75 
days (large errors included) for the orbit. The great French astronomer 
also calculated the time of conjunction in the intervals 1858—63, 1869-77, 
and 1885-92, and showed that the transits are regulated by a period of 
about seventeen years. The transit may be expected in the middle of each 
of those periods, but not for a number of years afterwards. After having 
