METAMORPHOSED FUCOID SCHISTS IN SCANDINAVIA. 155 



" Since the 1st of January IS^S, there have been made observations four 

 times a day, without interruption, and with all three instruments. Perhaps 

 I may succeed, in the last year of the co-operation, to continue the observa- 

 tions every two hours. 



" The perturbations of the magnetic declination and intensity in the year 

 184'4', viz. : 



" February 1. I. ; 2. D. I. ; 17. 1. ; 28 (trace). 



" March 2. D. I. ; 4. D. I. ; 5. D. I. ; 7. D. I. ; 30 a.m. and p.m. D. I. 

 " July 7. I. August 9. I. 

 have been so trifling that it is not worth while to mention them for the pre- 

 sent, but they will be communicated hereafter. 



" You shall not have to wait long for the observation books of the year 

 1841, and those of the year 1842 will be forwarded in a few months. I hope 

 the entries of the observations of the year 1843 will also be finished in the 

 spring of 1845. 



" Sir Bernhard will have conveyed to you already mj' sincere thanks, as 

 also those of the Silesian Society, for the Reports of the British Association 

 till the year 1842 inclusive, which you had the kindness to remit me. 



" I regret much that I am also this year prevented, for want of a substitute, 

 to express to you personally my obligations and to follow your kind invitation 

 in order to enjoy days of instruction at the Meeting of the British Association. 

 I beg you will please to convey to them my best thanks and my apology. 

 " I remain, with sincere regard, dear Sir, your obedient Servant, 



"Lieut.-Col. Sabine." " Henry von Boguslawski." 



On the Influence of Fucoidal Plants upon the Formations of the Earth, 

 on Metamorphism in general, and particularly the Metamorphosis 

 of the Scandinavian Alum Slate. By Prof. G. Forchhammer, 

 Professor of Geology and Chemistry, Copenhagen. (Printed among 

 the Reports by direction of the General Committee). 



It is for geology to explain, how the enormous quantities of matter, soluble 

 and insoluble, which the numerous rivers carry to the sea, arere-deposited, 

 and employed to form new beds on the crust of the earth. With the insoluble 

 portion, comprehending by far the greater part of the substances which are 

 thus carried into the ocean, geologists have indeed much occupied themselves, 

 and have given satisfactory explanations by showing, that enormous beds of 

 sand and clay owe their origin to this action ; but hardly any natural philo- 

 sopher has tried to explain, what becomes of the vast quantities of soluble sub- 

 stances which the rain dissolves from the solid earth, and ultimately carries 

 into the sea. Among these substances, sulphuric acid, arising from the solution 

 of gypsum, and silicate of potash dissolved during the decomposition of fel- 

 spar, are the most important, though by no means the only ones that occur. 

 If we consider that clay is produced by the decomposition of felspar, and 

 that a quantity of alkali (principally potash) proportional to the clay must 

 have been dissolved in the water, the question that must strike every observer 

 is, where has this enormous quantity of alkaline substances gone, and into what 

 combinations has it entered, since we find so very trifling a quantity of it in 

 sea-water? 



It is evident that there must be some great accumulating power, which 



