205 
the Observatory of Athens, of a splendid meteor on the 19th 
of October, at 2 55 a.m. Mr. Schmidt was occupied 
in observing shooting stars, and saw the one in question 
at its commencement. At first it appeared like a star of the 
fourth magnitude after two seconds, it was of the second 
magnitude; at the third and fourth second, it surpassed 
the splendour of Sirius. It slowly passed towards the west, 
appearing a dazzling meteor of 10' to 15' diameter. At this 
moment M. Schmidt followed the meteor with his telescope 
for fourteen seconds. Its appearance was most remarkable. 
There were two brilliant bodies of a yellowish green in the 
form of elongated drops, each followed by a well defined tail 
of reddish colour. These were followed by smaller luminous 
bodies of the same shape, each followed by its red trace. 
The meteor disappeared at an elevation of 1° above the 
horizon. Four minutes afterwards M. Schmidt still observed 
the remains of the meteoric train of a yellowish white, and 
covering an area of nearly 5°. 
The above observation is extremely important. It shows, 
firstly, that meteors are probably for the most part of a com- 
pound nature, consisting of a greater or less number of bodies 
associated together by the force of gravitation — small systems 
in fact ; and, secondly, that they present evident marks of 
fusion, either in the whole or in part, after passing some time 
through the rarer portions of our atmosphere. 
The researches by Professor Thomson and myself enable 
us to arrive at reliable conclusions with respect to the tem- 
perature acquired by bodies moving rapidly through the air. 
The law r is very simple, viz.: — The temperature ultimately 
acquired by the moving body is the equivalent of the force 
with which the particles of air come in contact with it. It 
is, in fact, the temperature acquired by each particle of air on 
being caught and suddenly dragged on. This temperature, 
cleared from the effects of radiation, is 1° C. for a velocity of 
145 feet per second, and goes on increasing with the square 
of the velocity. 
