2<)2 Progress of Science respecting Igneous Meteors in 1823. 



by Sir John Pringle's collection of observations on that which 

 appeared in 1 758, for example ; by Dr. Blagden's memoir 

 written on occasion of that of 1 783 ; and likewise by the obser- 

 vations on the American meteor of 1822, of which I have al- 

 ready given a summary. 



The elongation of the flames enveloping the nucleus of me- 

 teors, from the resistance of the atmosphere to their immense 

 velocity, seems to produce the caudate appearance, always in 

 the direction opposite to that of their motion by which the 

 majority of them are characterized ; and from which also they 

 have been described as conical and pear-shaped, and compared 

 in figure to trumpets, &c. ; cases of this sort it would be su- 

 perfluous to adduce, as every memoir upon the subject is re- 

 plete with them. 



The same may be said of the luminous tracks which are so 

 frequently left in the atmosphere by meteors of this description ; 

 and several instances of them have already been noticed in this 

 paper. They appear scarcely explicable but on the supposi- 

 tion that they consist of ignited solid matter in a state of mi- 

 nute division, and resulting from the combustion going on in 

 the meteors whose aerial course they distinguish. 



I have stated, at the outset, my reasons for bringing forward 

 the foregoing brief statement and cursory illustrations of the 

 opinion respecting the nature of Bolides, which the comparison 

 of a variety of accounts of them has induced me to form : the 

 subject involves many others, and some of great interest : such, 

 for instance, as the determination of the species of combustion 

 going on in these meteors ; the data for which are the pheno- 

 mena with regard to the evolution of light and heat of the 

 fire-balls themselves, the nature of the substances cast down 

 by their explosions, and the results of Sir H. Davy's ' Re- 

 searches on Flame.' 



The examination of these subjects, however, I must reserve 

 for another place ; and with merely an allusion to the bear- 

 ing of the question on which I have endeavoured to support an 

 opinion, upon the comparison of the computed magnitude of 

 any one meteor with that of another (see p. 116.), and also on 

 the great variation in apparent diameter of the same meteor as 

 seen by different observers (ibid.), I will conclude this digres- 

 sion; and proceed with the historical review of the progress of 

 science respecting igneous meteors during the past year. 



M. Moreau de Jonnes, to whom science is indebted for much 

 information respecting the climate, physical geography, and 

 natural history of the West Indian Islands, communicated to 

 the 1 loyal Academy of Sciences of Paris, on the 30th of De- 

 cember 1822, an extract of a letter from Fort Royal, in Mar- 

 tinique 



