158 ROCHESTER ACADEMY OF SCIENCE. 



fragment of moderate size of either an iron or a stone meteorite 

 will show its character fully. When these fragments are above 

 one or two inches on a side, and one of the sides has an original 

 surface or crust, it matters little from a rigidly scientific point of 

 view whether they are of said size or are twice or thrice as large. 



But often, when a very rare meteorite is under consideration, 

 only a very small fragment — perhaps only five or ten grammes, or 

 even less — is obtainable. Such fragments, though insignificant in 

 appearance, have still a very material value, showing at least the 

 color and petrographic character of the meteorite. No collection 

 can despise or omit to give place to such specimens. The Royal 

 Museum of Vienna has recorded in its catalogue twenty-seven 

 meteorites weighing one gramme each, and sixty-four specimens 

 weighing five grammes or under. The British Museum has fifty- 

 two kinds weighing not over five grammes each. It may be given 

 as a negative factor of value of a meteorite collection, that it con- 

 tains few very small bits. Yet to omit these altogether would take 

 important material from a collection. 



It merits notice that the larger the meteorite collection the 

 greater will be the number of these small specimens. Their 

 scientific value is acknowledged, their minuteness is a feature 

 which is unavoidable. Octibbeha is a siderite with a most excep- 

 tional quantity (62 -per cent.) of nickel in its composition, and 

 furthermore, is prehistoric. Small pieces (one or two grammes) of 

 this may be obtained with much difficulty and expense. But a 

 hundred thousand dollars would not supply a two-ounce piece. We 

 will not omit Octibbeha because it must appear as a minute specimen. 



Finally, while small specimens — of a very few grammes — are 

 often, an index of the especial wealth of a meteorite collection, 

 there may be, and are, many cases where many score of kinds are 

 represented by these fragments, when with time much larger 

 pieces of the same fall would be attainable. 



For all these reasons it is correct to consider the average weight 

 of the specimens as an important factor in the value of a meteorite 

 collection. 



But it often happens that a collection may possess a few pieces 

 of very large size, several hundred pounds in weight. To relieve 

 the estimate of this highly vitiating feature in computing average 

 weight, we would limit the estimate j-i? as to include otilv fifty pounds — 

 say, ttventy-five kilograms — of any one meteorite kind. 



