IqS ROCTTESTER ACADErvIV OF SCIENCE. 



Herschel, have a nucleus much larger than cherries or chestnuts. 

 All these are in the upper air, from 70 to 100 miles above us. The 

 larger masses pass on and undergo the terrible ordeal of heat and 

 erosion; under which the largest pieces are promptly reduced to 

 smaller ones, perhaps not one tenth of their original size, and the 

 smallest pieces are worn out and dissipated entirely. Probably no 

 aerolite which entered our air smaller in size than the human head 

 ever reached our earth. The siderites have unquestionably resisted 

 better the forces of attrition, but of all the many million meteorites 

 (scientists' estimates range from ten to twenty million) which 

 enter our atmosphere daily, probably less than a score reach our 

 earth, either as large or as small pieces. We do not sufficiently rec- 

 ognize the beneficent service to us which is performed by the cushion 

 of protecting atmosphere above our heads. It may be said inci- 

 dentally that the meteorites, both iron and stone, which reach our 

 earth and have been collected run in size from tiny bodies no larger 

 than peas all the way up with almost even gradation to blocks two 

 or three feet in diameter. The latter is the limit of the stones, the 

 largest one on record being the Long Island, Kansas, which is nearly 

 three feet long and weighs with all its fragments 1244 lbs. The 

 present specimen, Bath Furnace No. 3, is believed to be the third 

 aerolite in weight (177M lbs.) ever found on our hemisphere. 

 Iron meteorites run much larger. The two largest which have been 

 weighed are the IMexican Chupaderos weighing 15^^ tons, and the 

 Cape York Anighito, weighing 36^ tons. Bacubirito, an iron me- 

 teorite, still lying in a valley of the Cordilleras in the State of Sina- 

 loa, Mexico, is longer and wider than either of the preceding, but 

 not so thick as the Greenland mass. When this Sinaloa mass is 

 weighed, it will be known which country, Mexico or Greenland, has 

 to its credit the heaviest meteorite so far known on our earth. 



Once more let us look at our meteorites in the upper heavens. 

 They have entered our atmosphere as rough, angular masses which 

 would at first, for a short section of their flight, have a rotating 

 movement imposed upon them by the air's resistance.. Then, their 

 angles and their projections being worn away and their center of 

 gravity established, their course becomes direct, and is marked by 

 a long, unbroken stream of light, with sparks flying through and 

 out of it. The head of this stream is larger than the part which 

 follows, and all are greatly larger than the meteorite kernel which 



