CONTENTS OF VOLUME XVIII. 



NUMBER I. 



Page. 

 Art. I. Of the Phenomena and Causes of Hail Storms. By 



Professor Denison Olmsted, - - - - i 

 II. Architecture in the United States, - - - - 11 



III. Sketch of a Classification of the European Rocks ; by 



Henry T. De la Beche, Esq. F. R. S. H. - - 26 



IV. On the Rectification of the Ellipse ; by C. Wilder, 38 

 V. Notices and Observations on the American Cicada, or 



Locust ; by Dr. S. P. Hildreth, - - - 47 



VI. The Gold of the Carolinas in Talcose Slate; by 



Prof. Eaton, .__--_- 50 

 VII. On the Ofiice of the Nitrogen of the air, in the process 



of Respiration ; by Prof. Lewis C. Beck, M. D. - 52 

 VIII. Notice of Animalcules in Snow ; by Dr. Joseph E. 



Muse, __------ 56 



IX. The Iodide of Potassium, (Hydriodate of Potassa of 

 the shops,) as a test for Arsenic; by Prof, J. P. 

 Emmet, Univ. Virgin. ----- 58 



X. On the Dew Point ; by A. A. Hayes, - - - 63 

 XI. On the cause of the peculiar aspect of the air, in the 



Indian Summer, „_---- 66 



XII. Solution of a Problem in Fluxions; by Prof. Theo- 

 dore Strong, -------67 



XIII. On capillary attraction ; by Prof Theodore Strong, 70 



XIV. Particulars respecting an irised Aurora Borealis ; by 



James Bowdoin, Esq. ------ 72 



XV. Notice and description of a Marine Ventilator ; by 



Samuel Whiting, .__--- 75 



XVI. Notice of some Localities of Minerals, near Baltimore, 

 Md. ; by Philip T. Tyson. With an Appendix, by 



C. U. Shepard, 78 



XVII. On the Crystalline Form of Iodine ; by Lieut. W. W. 

 Mather, Assist. Prof of Chem. and Min. U. S. Mil. 



Acad. W. P. 84 



XVIII. On the Transition Rocks of the Cataraqui ; by Capt. 



R. H. Bonnycastle, R. E. Canada, - - - 85 

 XIX. On the Sulphate of Strontian, Kingston, (U. C.) ; with 

 notices of the Geology of the vicinity; by Lieut. 

 Baddeley, - - - - - - -104 



XX. On the Vegetation of the First Period of an Ancient 

 World ; by Henry Witham, of Lartington, (Eng.) 



F. G. S. &c. 110 



XXI. On the use of the Anthracite Coal in the making of 



Brick ; by William Meade, M. D. - - - 118 



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