Meteorite Collection — Handbook and Catalogue. 15 



hind the advancing mass in the form of an igneous globe, making a 

 flame shaped like that of a candle, and under the intense heat a large 

 portion of the mass is dissipated into a vapor or smoke. The heat 

 moreover, causes cracking of the surface (Linn Co., 255, Dona Inez, 

 193) and an unequal expansion of the mass which bursts it, often 

 with explosive violence. 



In spite of the high temperature to which its surface is raised, 

 however, the substance of the meteorite is so poor a conductor that 

 its interior is often scarcely heated at all. When picked up immedi- 

 ately after their fall, therefore, meteorites are often scarcely more 

 than blood warm and in one remarkable instance, that of the Dhurm- 

 sala (275) meteorite, the fragments were so cold as to benumb the 

 fingers of those who collected them. This is perhaps the only in- 

 stance known in which the cold of space has become perceptible to 

 human senses. 



Another effect of the passage of a meteorite through the earth's 

 atmosphere is to reduce very greatly its velocity, so that the speed of 

 its fall when near the earth is comparable to that of an ordinary fall- 

 ing body. Hence instead of striking the earth at a velocity of from 

 10 to 45 miles a second, which is that at which meteorites enter the 

 atmosphere, their force of impact may be very small. This is shown 

 by the fact that several stones of the Hessle (298) fall, struck upon 

 ice which was only a few inches thick and rebounded without either 

 breaking the ice or being themselves shattered. 



By dissipating, therefore, the smaller stones before they reach the 

 earth and by reducing both the size and velocity of those which do 

 come to it, the atmosphere protects us from what would otherwise be 

 a dangerous bombardment, and makes the chances of injury to life or 

 property from the fall of these bodies exceedingly small. 



The forms of meteorites are very various and possess little regu- 

 larity. Many are spheroidal (Pultusk, 290), some oblong (Babb's 

 Mill, cast, 383), some tetrahedral (Mocs, 330), some shell-like as if 

 scaled from a spherical mass (Canon Diablo, 373) and many so irregu- 

 lar as to be lacking any definite form. They are as a rule as indefi- 

 nite as to size and shape as the fragments from any block of stone 

 when shattered with a hammer and it is therefore probable that they 

 have been formed by the breaking up of a larger mass. 



Such a disruption of a meteorite often takes place shortly before 

 it reaches the earth, and as a result many individuals of a meteoric 

 shower possess edges which are still rough and jagged and show little 

 fusion of the surface (Winnebago Co., 34°). Perhaps the most remark- 

 able instance of this. is furnished by the stone of the Butsura (398) 



