1913.] EXCHANGE VALUE OF METEORITES. 521 



Occasional Factors. 



6. Area of slice offered. 



7. Phenomenal variation between individual specimens. 



8. Distinctness of structure. 



9. Missing portions. 

 10. Historical interest. 



1. Present Knoimi Weight. — Wiilfing distinguishes between the 

 original weight and the present known weight among recorded 

 owners. After the original weight is announced, usually the only 

 important loss is by sawing, etc. ; hence the portions held by unknown 

 owners should not be ignored. In general the present weight may 

 be approximated by subtracting from the original weight, a loss of 

 10 per cent, to 30 per cent., according to the extent and manner of 

 division. 



Evidently we have here supply versus demand in its simplest 

 aspect. Thus, Canyon Diablo and Toluca are at one end of the list, 

 with many tons distributed, and respectively offered at 3 cents and 

 4 cents per gram, or only double the price of silver. Omitting Adalia 

 and one or two others of which only a few grams are known, we 

 may take as typical of the most costly meteorites, Angra dos Reis, 

 Barea and Epinal, with an average known weight of 1,000 grams. 

 These bring over $7.00 per gram, or ten times their weight in gold. 



2. JJ^eight of Specimen Offered. — This variation is based on the 

 high costs of sawing irons, as well as on the consequent loss of one 

 tenth to three tenths of their mass ; and finally on the expensive 

 distribution of all kinds of meteorites to the most limited, yet widely 

 scattered, of markets. While this principle is generally recognized 

 in practice, the fact that it is second only in importance to the weight 

 of the fall, is frequently overlooked. Although excluded by Wiil- 

 fing, if allowance is not made for this element, his system often 

 becomes misleading in individual transactions. Its relative im- 

 portance is shown by many sales. Thus, Canyon Diablo, of which 

 fifteen to twenty tons have been distributed, brings in 100 gram 

 pieces 3 cents per gram, and in 100 kilogram pieces three tenths 

 cent per gram, or $3.00 per kilogram. That is, a thousand fold 



