A CATALOGUE OF OBSERVATIONS OF LUMINOUS METEORS, 335 
Hence it appears that the height of shooting-stars in August 1863 was 
little different from their height in 1861. 
(3.) Professor J. Jos. Bianconi of Bologna has addressed the following con- 
siderations to the British Meteorological Society, respecting a mechanical 
theory of the light and heat of luminous meteors advanced formerly by him- 
self in 1839, and recently communicated to the British Meteorological 
Society. The observations of the luminous trains of meteors conducted by 
Professor Respighi, Dr. Casoni and himself, in August 1863, have tended to 
confirm Professor Bianconi in the opinion that heat, partly that of friction, 
and partly that of compression, is sufficient to volatilize superficial portions 
of meteorites, so as to produce the rounded edges and erosions of their sur- 
faces, as well as the atmosphere, or halo of light, about the meteors, which 
remain in a luminous streak upon their track. ‘‘ Admitting that the heat of 
friction is sufficiently powerful to maintain the fusion of the surface, the incan- 
descence of the planetoid, and besides this the sublimation of the melted matter 
which goes to form the tail, we see that this feature can only be developed 
where the heating conditions have the greatest power—namely, near the 
middle of the flight. It will begin gradually, at first not so ample, becoming 
very abundant at the middle of the flight, then diminishing again, and just 
ceasing when the course of the meteor is so slackened as to be incapable of 
producing the necessary heat....... We find also in the undulated form of 
the luminous tail of the bolide, the movements peculiar to heated vapours left 
in the middle of the atmosphere. In short, these few observations lead us to 
conclude, first, that heat produced, as we are authorized to believe, by friction 
is not only calculated to produce incandescence and fusion, but that it attains 
to a higher degree—that of causing a sublimation of the surface-matter of 
the asteroids, which sublimation or volatilization forms a luminous atmosphere 
around the falling body, varying in volume according to the intensity of the 
source of heat; secondly, that this luminous atmosphere left to itself, the tail, 
disappears partially and by degrees, principally on account of its dimensions, 
temperature, and density; and that, whilst its particles accumulate con- 
centrically, it contracts and changes its form with the variations peculiar to 
vapours.” 
The observation of a large bolide with an enduring streak, on the evening 
of the 10th of August, 1863, by Professor Bianconi, and Dr. Casoni at 
Bologna, is noticed in the Catalogue of this Report. 
VI. Transactions or THE ImpERIAL ACADEMY OF VIENNA, Vol. xliv. 
Dr. Julius Schmidt has represented varying phases of the luminous streaks 
of meteors near the radiant point, on the 10th of August 1860 and 1861. 
Trains of shooting-stars (visible to the naked eye for two or three seconds) 
were traced in the field of a telescope for one, two, or even three minutes 
before they finally disappeared. Points of explosion of the meteors produced 
stationary clouds of light ; but intermediate lines of the train moved in various 
figures with looped curves to a distance from the stationary points. Train- 
fragments were observed to separate from one another three degrees in three 
minutes of time. 
VII. American Journat or Science anv Art, vol. xxxvi. July 1863. 
“Remarks on the luminosity of meteors as affected by latent heat,” by 
Benjamin V. Marsh, Philadelphia. 
