History of Astronomy for the Year 1805. 241 
makes us wish for other measurements of degrees of longi- 
tude which are not affected by these irregularities. —Phil. 
Trans. 1804. 
M. de Zach has continued the measurement of his de- 
grees of the longitude and latitude of Capel, at Gotha; he 
hopes next year to finish 4° of longitude. 
M. de Zach has been making observations at Hieres, Aix, 
and Avignon, for these 17 years past: he has found 897 
toises for the height of Mount Ventoux. He expects to 
finish in Provence the celestial arc between the mountain 
Saint Victoire, and the pillar of Cette in Languedoc, for 
the degree of longitude measured in 1739, and upon which 
there had been always some doubt entertained. 
He observed at the Isle of Planier, the most southern 
point in France. General Roy had formed some doubt upon 
the longitude of Porquerolle; M.de Zach determined it. 
In the month of March there appeared a large spot with 
two nuclei upon the sun, whick J observed at 9° to the north 
of the solar equator: this differs little from the beautiful 
spots which I made use of in determining the rotation of 
the sun in the memoirs of the academy for 1776, and which 
were from 11 to 12 degrees. This seems to confirm the dis- 
covery I then made, proving that there are in the sun some 
points where great spots are formed in preference to others : 
» perhaps these spots are mountains, which attract and retain 
the scorie of this immense furnace. The parallel, which is 
9° to the south of the equator, abounds most in large spots. 
These spots with two nuclei, which have appeared at dif- 
ferent epochs (Mem. 1776 & 1778), seem to me to over- 
turn the system of volcanoes proposed by Herschel. 
The beautiful spot of the month of March had its middle 
at 101 degrees of declination. That of which I calculated the 
appearance (Mem. 1776, p. 496) had from 11° to'14°; but a 
spot of a minute occupies near 4°: thus the mountain which, 
I suppose, served it for the foundation or obstacle to arrest 
and to fix it by, may rather, by taking it at a different point, 
draw it to 2° or 3° further in one appearance than in the 
other. 
Vol. 26, No, 103, Dee, 1606. Qu M., de 
