[ 338 j 
XLVIL. On certain Inductions with respect to the Heat engen- 
dered by the possible Vall of a Meteor into the Sun; and ona 
mode of deducing the absolute Temperature of the Solar Surface 
from Thermometric Observation. By J. J. Waverston, Esq.* 
R. CARRINGTON’S observation of the sun on the Ist of — 
- September last having fortunately established the fact of 
an outburst of light above the solar surface, and thus favouring 
Newton’s conjecture as to the sun receiving a supply of force 
from bodies descending upon it, it may be worth while, and 
perhaps assist in the formation of more exact ideas on the sub- 
ject, if we compute, from Mr, J oule’s value of the thermal unit, 
the quantity of heat and intensity of temperature that would 
accrue by a body falling into the sun or sun’s atmosphere with 
the velocity due to a parabolic trajectory. The modern inter- 
pretation of Newton’s conjecture is, that the comet, or by what- 
ever name we call the body, does not supply fuel to a fire as oil 
to a flame, but that it supplies force to the central radiating 
energy—force to be converted into heat and light. 
It is true that no body belonging to the solar system can fall 
into the sun so long as the laws that keep them in their orbits 
are maintained. A body that has once rounded the sun in a 
parabola or elongated ellipse, will probably continue to do so, 
unless in the rare case of the perihelion distance being so close 
to the sun’s surface that a slight perturbation from the other 
bodies of the system may bring it within the limits of the sun’s 
radius. But when the orbit is a hyperbola, it is the first and 
last appearance of the body ; and if, as may chance to happen, 
the perihelion distance is less than the sun’s radius, the sun must 
inevitably absorb it. We are thus certain that the velocity of a 
body that impinges on the sun must exceed 419 miles per second ; 
for such is the orbital velocity in the parabola that separates the 
lesser velocity in the ellipse from the greater velocity in the hy- 
perbola. 
With this velocity and Mr. Joule’s unit it is easy to compute 
the quantity of heat due to the conversion of the force; and if 
the absolute zero of temperature coincide with —461° F., the 
zero of gaseous tension, the temperature attainable by a known 
substance under such conditions may also be exactly computed, 
independent of any theory or hypothesis whatever. 
A pound of water falling through 772 feet acquires a velocity 
of 222 feet per second, and a force that, if converted, raises the 
temperature of the pound of water 1°F. If it falls through four 
times 772, the velocity acquired is twice 222 feet, and the rise 
of temperature 4°. Suppose the acquired velocity to be 1 mile 
* From the Proceedings of the Astronomical Society for April 3, 1860, 
