Sulphat of Strontian. 363 



3. Remarks on the study of Geology. 



In a recent letter to the editor, from William Maclure, 

 Esq. President of the American Geological Society, dated 

 at Paris, are the following remarks : " It has always appear- 

 ed to me that the science of geology was one of the sim- 

 plest and easiest to acquire of any : the number of names 

 to be learned is small, and the present nomenclature al- 

 though rather generic than specific, is not difficult. In teach- 

 ing geology I would have a cabinet of specimens containing 

 all the rocks divided into four classes, or as many of them as 

 I could procure, keeping always in mind, that the most com- 

 mon are the most useful. I would begin by giving the stu- 

 dent an exact idea of all the rocks of transition, at one end 

 of which he will find the primitive, and at the other the sec- 

 ondary, which two classes are so different in their structure 

 as not to be easily mistaken. The alluvial rocks encroach 

 on the secondary, as soon as they have remained in contact 

 long enough to adhere, and take the consistence of rocks, 

 for the whole secondary, was at one time, alluvial, when 

 they were first deposited by the waters, excepting always 

 the volcanic." 



We are not willing to withhold an additional remark : — 

 when speaking of this Journal, he observes : "In some of 

 the memoirs of geology there it a little inaccuracy in the 

 names of the rocks which should be as strictly scientific as 

 possible ; the Wernerian nomenclature is still the best under- 

 stood." 



Every such hint, coming from such an authority as Mr. 

 Maclure than whom no man (with the single exception of 

 Col. Gibbs,) has so good a right to give advice on the sub- 

 ject of American geology, is worthy of attention and will 

 have its full weight in this country. 



4. Sulphat of Strontian. 



Extract of a letter to the editor from Professor Douglass of the Military- 

 Academy at West-Point, dated Black Rock, (N. Y.) May 5th, 1820. 



My Dear Sir, 



The mineral which I had announced to you upon a slight 

 examination of it as sulphate of barytes, (see Vol. II. p. 241) 



