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ADDENDA. 



has been insisted on with some pertinacity, and supposed to receive 

 almost demonstrative support from considerations to which I shall 

 presently refer. I am by no means disposed to quarrel with the 

 nebulous hypothesis even in this form, as a matter of pure speculation, 

 and without any reference to final causes ; but if it is to be regarded 

 as a demonstrated truth, or as receiving the smallest support from any 

 observed numerical relations which actually hold good among the 

 elements of the planetary orbits, I beg leave to demur. If we go on 

 to push its application to that extent, we clearly theorize in advance 

 of all inductive observation." — Address to the British Association held 

 at Cambridge, in June 1845 ; by Sir J. F. W. Herschel, Bart. 



Olbers on Aerolites, page 52. — The statement in the text is 

 erroneous. Olbers expressly comments on the non-discovery of meteor- 

 olites in tertiary and secondary strata, and inquires whether from the 

 absence of fossil meteoric stones we are to infer that previous to the 

 last and present arrangement of the earth's surface, no Aerolites had 

 fallen upon it ; though, according to Schriebers, it is probable that 

 the phenomenon now occurs not less than 700 times annually ] — See 

 Humboldt's Cosmos, translated by Col. Sabine. 



Masses of native iron containing nickel, have however been discovered 

 in Northern Asia in an auriferous deposit, at a depth of 40 feet : and 

 also in the Carpathian mountains ; and these masses are very like 

 undoubted meteoric stones. 



There is a fine collection of Aerolites, admirably arranged by Mr. 

 Konig, in the gallery of minerals of the British Museum. 



Charing Chalk Detritus, page 324. — Since this notice was 

 printed, Mr. Harris has favoured me with a more particular description 

 of this interesting deposit. The village of Charing is situated on the 

 bed of detritus, which in many places is twelve feet thick. Mr. Harris 

 has obtained from it most of the species of Foraminifera which occur in 

 the chalk and in the tertiary strata of the Paris Basin. Cytherina 

 (marine crustaceans allied to the fresh- water Cyp rides, ante, p. 405,) 

 abound in the detritus, and also in the neighbouring chalk and chalk- 

 marl. From the abundance of small land and fresh-water shells 

 associated with these cretaceous forms, Mr. Harris infers that the 

 neighbouring dry land was clothed with vegetation before this local 

 drift was formed. 



