100 THE PRESIDENTS ADDRESS. 
was gained, not, however, without the most imminent risk to the 
aeronauts. In reading the very interesting account of this ascent, we 
cannot contemplate without admiration the coolness with which one 
of the adventurers continued his scientific observations until at length 
at some five or six miles above the surface of the earth, he lost all, 
power of eyes and limbs, and fell back in the car as in sleep, and the 
presence of mind with which his companion, when his hands had 
failed him, “seized the line between his teeth and pulled the valve ~ 
open until the balloon took a turn downward,” and the numbed ob- 
servers were thawed into consciousness. 
During the past year two comets have been visible—one by com- 
putation only nine millions of miles from the earth. The other, and 
the more remarkable of the two, continued within the circle of per- 
petual apparition for five weeks, but when nearest to the earth was 
distant thirty-three millions of miles. 
In connexion with this subject, I have pleasure in calling attention 
to a magnificent volume, giving a full account of the great comet, of. 
1858, by Mr. Bond, Director of the Observatory of Harvard College. 
This is, so far as Lam aware, the most complete work on the subject 
that has ever been published. 
The government of Ecuador have offered to the French govern- 
ment the site for an observatory on the plateau of Durito. This 
locality presents almost unequalled advantages for observation from 
its position on the globe, and from the remarkable clearness of the 
atmosphere. The parallax observations, which have been made 
during the past year, taken in connexion with Foucault's experi- 
ments on the velocity of light, and Struve’s measurement of an are 
of parallel, promise the most important results relative to the ques- 
tion of the sun’s distance. 
But little calling for special notice, on such an occasion as the pres- 
ent, has been done during the year in pure mathematics, but a most 
remarkable example, illustrating their beauty and their power as ap- 
plied to coustructive mechanics, has been presented by the explana- 
tion given by the Astronomer Royal, of the directions and magnitudes 
of the strains on the sides of tubular bridges. It must be most 
gratifying to Prof. Airy to find that his theory was accepted not 
only by mathematicians, who admired the skill with which he pro- 
duced the equations and the ingenuity with which he rendered them 
manageable, but also by practical men, such as Mr, Fairbairn and 
