GREAT METEORITE COLLECTIONS. 157 



of a possible 600, the whole 200 should be of the most inferior 

 kind, although in fact this would rarely be true. But if there were 

 400 kinds, several of the other conditions of excellence would be 

 necessarily met. In actual fact — as meteorite collections are ordi- 

 narily made — the presence of a very high number of kinds is a very 

 certain index of other excellence. In a practical way the presence 

 of a great number of kinds in a meteorite collection vastly facili- 

 tates comparisons and scientific study of the whole. The earnest 

 efforts of the largest museums — controlled by sober, sensible 

 scientists — to increase to the highest attainable point the number 

 of their localities, is an index of the general appreciation of the 

 value of numbers as a factor of merit. Large numbers show effort, 

 study, and money outla3\ The argument is practically a sure one 

 that excellence has resulted. In a word, the factor of number of 

 kinds will always take a high, leading position in rating a meteorite 

 collection. 



AVERAGE WEIGHTS AND SIZES OF THE INDIVIDUAL SPECIMENS OF 

 THE COLLECTION. 



The ideal of a meteorite collection might be that each speci- 

 men should be undivided — the entire bolide as it existed in space. 

 It is unnecessary to tell how, from the inherent conditions of the 

 subject, this in actuality cannot be. By far the greater number of 

 the falls are accompanied by explosions of the mass in the air or 

 by its breaking in reaching the earth. In the largest collections — 

 as in the smaller ones — fully seven-tenths of the specimens are 

 pieces taken from the larger masses, or are masses with smaller 

 pieces taken from them. The exceptions are more commonly cases 

 where several — sometimes many — bolides have fallen in the same 

 meteoric shower. With these latter, the collector must accept 

 them as they fell — large or small. Of pieces broken or cut from 

 larger masses, the collector's desire will be to get a piece so large 

 that it will show well all the features both of outer and of inner 

 structure. A piece with surfaces of several square inches' super- 

 ficies is none too large for this purpose. And with great masses of 

 one or more feet in diameter, there is ever something additional to 

 be seen. Furthermore, there is something imposing and impres- 

 sive in the size itself of the Great Thunderbolt. A certain number 

 of these great masses are cherished-and placed prominently in the 

 large collections which are fortunate in possessing them. Purely as 

 a matter of scientific interest — setting aside the entire bolides — a 



