CHICORA METEORITE — PRESTON, HENDERSON, RANDOLPH 407 



perature ranges comparable to those found on the moon or Mercury. 

 And because the material is a poor conductor of heat, this alternate 

 heating and cooling would set up temperature stresses and form cracks 

 extending deeply into the mass, even as they do into a pot of optical 

 glass. 



If this big meteorite had come straight down instead of at this long 

 slant, it would have reached the earth with a lot of its structure still 

 intact and a lot of its energy still in it. And if it had landed on Pitts- 

 burgh there would have been few survivors. Its kinetic energy of 

 31,400,000 foot-pounds per pound is more than 20 times as great as 

 the explosive energy of TNT. 



At least its capacity for destruction would have compared favorably 

 with that of the shipload of TNT that blew up in Halifax Harbor in 

 1917. And such a catastrophe, or even a very much larger one, can 

 happen at any time, with no more warning than the observers of the 

 Chicora meteorite had. But fortunately the energy of this meteorite 

 had all been absorbed by the air before it reached the ground. 



MINERALOGICAL DESCRIPTION OF THE METEORITE 

 By E. P. Henderson 



Only two specimens of the Chicora meteorite have so far been re- 

 covered, the larger one weighmg 242 grams and the smaller 61 grams; 

 both are deposited in the United States National Museum (No. 1326). 

 The latitude of the place of discovery is 40°56' N. and the longitude 

 79044/ ^ Both individuals are covered with a thin film of black 

 fused crust, and neither shows any evidence of being orientated 

 through much of its ihght. Shallow and irregular depressions (thumb 

 marte) are noticeable on each, but no unusual physical features are 

 present. 



When the crust was removed a fine-grained texture was found 

 exhibiting a rather uniform gray color. All the component minerals 

 are so small that none coidd be recognized by the unaided eye, unless 

 it be an occasional inclusion of bronze-colored troilite. On the 

 freshly broken surface no conspicuous evidence was observed of the 

 chondritic natm-e of this meteorite, and not until a thin section was 

 prepared could positive proof of this be given. From the smooth 

 surface, made by cuttmg away a portion for the thin section, a dappled- 

 gray pattern is noticeable. The darker gray material is in rounded, 

 as well as slightly elongated, chondrules or portions of chondrules, 

 each being separated by a thin zone of lighter gray material. The 

 texture is just firm enough to make it slightly difficult to break apart 

 by the use of a steel tool. 



