PLATES. 



I. Illustrative of Mr. J. A. Phillips's Paper on the Composition and 

 Origin of the Waters of a Salt Spring in Huel Seton Mine. 



II. III. Illustrative of Mr. H. A. Rowland's Paper on Magnetic Permea- 

 bility, and the Maximum of Magnetism of Iron, Steel, and Nickel. 



IV. Illustrative of Dr. H. Draper's Paper on Diffraction-spectrum Pho- 

 tography. 



