284 MEMOIR ON METEORITES. 



about ten miles from Zapata. "The form is irregular. Its 

 greatest height is forty-six inches; greatest breadth thirty- 

 seven inches; circumference in thickest part eight feet three 

 inches. Its weight, as given by Senor Urquida, is about three 

 thousand eight hundred and fifty-three pounds. It is irregular 

 in form, as seen by the figure; and one side is filled with deep 

 cavities, generally round and of various dimensions. At its 

 lower part, as it now stands, is a projecting leg, quite similar 

 to the one on the meteorite at Tucson. The back or broadest 

 part is less jagged than the other portions, and contains fewer 

 cavities, yet, like the rest, is very irregular." 



PART II. 



THEOEETICAL CONSIDERATIONS. 



Under this head no mention will be made of the phenomena 

 accompanying the fall of meteorites, as their light, noise, 

 bursting, and their black coating, which arise after the bodies 

 have entered the atmosphere, and are brought about by its 

 agenc}^. This omission will affect in no way the theoretical 

 views under consideration, and the introduction of these par- 

 ticulars Avould uselessly increase the length of this memoir. 



The lessons to be learned from meteorites, both stony and 

 metallic, are probably not as much appreciated as they ought 

 to be. We are usually satisfied with an analysis of them and 

 surmises as to their origin, without due consideration of their 

 physical and chemical characters. 



The great end of science is to generalize facts that are ob- 

 served. Thus terrestrial gravitation has been extended to the 

 solar system, and in fact to the whole universe. The astronomer 

 by his discoveries only proves the universality of this one law 

 of nature operating on matter. He has found no evidence that 

 any other force pertaining to terrestrial matter displays itself 

 in a similar manner in other spheres. However true and self- 

 evident it may appear that all matter in space is under the 

 same laws, be they those of gravitation, cohesion, chemical 

 affinity, etc., it is none the less interesting to have the fact 



