108 Answer to Dr. Harems Letter. 



lations and age of this group might be satisfactorily fixed and de- 

 termined, and showing that it does not belong to the usual salif- 

 erous series, the new red sandstone. How far this is an anomaly 

 may be judged from the facts, that in England, " neither rock 

 salt nor salt springs occur in the middle or lower members of the 

 new red sandstone ; and hence the term ' saliferous,' as applied to 

 the lohole system, appears objectionable, since the marls in which 

 the salt lies, constitute only the upper portion of the mass," con- 

 sidered "as the new red system." "In certain parts of Germa- 

 ny, salt appears to pervade the underlying bunter sandstein ;" 

 " in other tracts of central Europe, it abounds in tertiary strata, 

 (Wielitzke, in Poland.) At Cardona, in Spain, it is found in rocks 

 of the age of our green sand ; in the Austrian Alps, it has been 

 shown by Prof. Sedgwick and Murchison, to occur in limestone 

 of the oohtic system ; whilst in many countries, including Eng- 

 land, saline springs occasionally burst out from the carboniferous 

 and older systems of rock."- — Murchison, Silurian Syst. p. 32. . 



The Report on the Geological Survey of N. York for 1839-40, 

 being public document 50, came too late for notice in the present 

 number. 



Art. XIY. — An answer to Dr. Harems Letter on certain Theoret- 

 ical opinions ; by M. Faraday.* 



My Dear Sir — i. Your kind remarks have caused me very 

 carefully to revise the general principles of the view of static 

 itiductio7i, which I have ventured to put forth, with the very nat- 

 ural fear that as it did not obtain your acceptance it might be 

 founded in error ; for it is not a mere complimentary expression, 

 when I say, I have very great respect for your judgment. As 

 the reconsideration of them has not made me aware that they 

 differ amongst themselves or with facts, the resulting impression 

 on my mind is that I must have expressed my meaning imper- 



* Royal Institution, April 27, 1840. 



Genileraen — Can you add to the favors I am already under by inserting in your 

 Journal my reply to Dr. Hare's letter addressed to me and published in your ex- 

 cellent work. I am, gentlemen, your obliged servant, M. Faradav. 



To the Editors of the American Journal of Science and Arts. 



