542 FOOTE— EXCHANGE VALUE OF METEORITES. [April 25, 



than half the given figure — even that would be an advance over the 

 present fearful confusion prevailing on questions of value." While 

 Wiilfing's formula has a large probability of error on account of his 

 exclusion of several highly important factors, it must be remem- 

 bered that without it or some similar system, meteorites would be 

 valued by a " rule of thumb," the elasticity of which is frequently 

 felt in the wide limits shown by exchange and market prices. 



It is certain that Wiilfing's work has lessened the absurd varia- 

 tions in value which abound in exchanging, and that it has also aided 

 in regulating trade prices. It is therefore to be hoped that a new 

 edition may be published in the not distant future. Nearly two 

 hundred meteorites are known besides the 536 which he recorded, 

 while the number of owners has increased. Unfortunately, Pro- 

 fessor Wi-ilfing replies, in response to a query, that he does not 

 contemplate a revision. 



Conclusion. — In the writer's opinion, no holder of a meteorite 

 should divide it before considering current trade prices of similar 

 falls, a practice which is already established in the present wide use 

 of previous collations. Likewise he should consult Wiilfing's tables, 

 which are based on present known weight, group weight and number 

 of owners. Finally, the exchanger should estimate the importance 

 of the following factors : Weight of specimen ofit'ered ; observation 

 of fall ; area of slice ofifered ; phenomenal variation between indi- 

 vidual specimens ; distinctness of structure ; missing portions ; his- 

 torical interest. 



It is certain that the stabilizing influence of a fuller consideration 

 of values by meteorite exchangers will tend to dispel an already 

 lessening hesitation among institutional owners, and result in that 

 freer distribution which Buchner and Wiilfing sought to bring about. 

 With its achievement, the advancement of this unfamiliar but grow- 

 ing science will have been distinctly furthered. 



