156 ROCHESTER ACADEMY OF SCIENCE. 



4. The proportion of specimens showing leading points in 

 meteorite classification — either chemical or petrographical. 



5. The proportion of specimens of great rarity— usually the 

 mass small at the outset. 



6. The completeness of original exterior structure, with crust, 

 pitting, orientation, etc. 



7. The proportion of specimens of traditional or of historical 

 value. 



8. The proportion of old falls in the collection. 



9. The extent to which the specimens have been treated by 

 cutting, polishing, etching, etc., to show inner structure. 



10. The broad geographical distribution of the specimens. 



11. All Siderites or Siderolites ever seen to fall. 



We will notice briefly some of the merits of each of these factors. 



number of distinct, well-authenticated kinds 



"falls and finds." 



It is here understood that the localities are quite distinct — not 

 repetitions of each other under different names. Nearly all collec- 

 tions contain specimens — outliers of falls and bearing different 

 names — which are really of one and the same fall, and should thus 

 count as one locality. Most falls have some outliers of this kind. 

 Pultusk, Mocs, Toluca, Coahuila, and others have each many of 

 them. These may be used, and often are so, to swell a collection, 

 where their presence attains redundance, without usually adding 

 an element of value.* 



In other cases the number of kinds in a collection is increased 

 by the introduction of those practically undetermined and often 

 unmeteoric. Such unauthentic specimens have no standing or 

 rating in a collection. They should be iveeded out, for their presence 

 is detrimental. 



If, then, all the specimens or kinds are genuine, a great number 

 of them is a great factor of value. The more of them that there 

 are, the more is the opportunity, or even the likelihood, that the 

 other conditions of merit in the collection are met. 



It might be that in a collection consisting of 200 meteorites out 



*Pultusk (Poland, Jan., 1868) was a shower over an area of about four by six miles. The 

 villages or hamlets included have added the following names to encumber nomenclature and 

 render deceptive the numbers in meteorite collections, useful as they may be in some other ways : 

 Pultusk, Psaly, Obryte, Zambski, Sokolowo, Gorstkowo, Sielce Nowry, Sielce Stary, Rozan, 

 Ciolkowo, Rowy, Zastruzny, Rozdialy, Rchwnie, Mrozy, Daborowka, Clrzonny, Ochulenka. All 

 these fell in a period of one minute between Pultusk and Ostrolenka, and are one meteorite — 

 Pultusk. 



