CONTENTS. 



APRIL, 1812. 



Engravings of the following Subjects : Dissections of Aquatic and semiaquatic 

 Plants, delineated from Nature, by Mrs. A. Ibbetson, in two Plates. 



I. On Fresh-water Plants. In a Letter from Mrs. Agnes Ibbeston 241 



II. On the Zigzag Motion of the Electric Spark. In a Letter from a Corres- 

 pondent - - - - - - 248 



III. Abstract of a Paper on Fermentation : by Mr. Gay-Lussac - 24§ 



IV. Note on Prussic Acid : by the same _ - - 256 



V. Abstract of a Paper on Triple Salts : by the same - - 259 



VI. Analysis of large-leaved Tobacco, Nicotiana tabacum latifolia and angus- 

 tifolia : by Mr. Vauquelin. - - - - 260 



VII. Mineralogical and Chemical Examination of Magnesite, the native Mag- 

 nesia of Werner : by Messrs Haberle and Bucholz - - 269 



VIII. Meteorological Journal ... - 278 



IX. Notice respecting the Geological Structure of the Vicinity of Dublin ; with 

 an Account of some rare Minerals found in Ireland. By William Fitton, 

 M. D. Communicated by L. Horner, Esq. Sec. to the Geological Society 



280 



X. On the Native Country of the Solanum tuberosum, or Potato. By Benja- 

 min Smith Barton, M. D. Mem. of the Am. Phil. Soc. &c. Communicated 

 by John Mason Good, Esq. F. R. S. Member of the Am. Phil. Soc. and 

 F. L. S. of Philadelphia - - - - 290 



XL On the Production of Electrical Excitement by Friction. By J. D. 

 Maycock, M. D. - - - - - 304, 



XII. On the Nature of Oximuriatic and Muriatic Acid Gas, in Reply to Mr. 

 Murray. In a Letter from John Davy, Esq. - - 310 



XIIL On the Compensation Pendulums of Lieutenant Kater and Mr. Reid, 

 In a Letter from a Correspondent - - - 3 IS 



XIV. A short Account of a new Apple, called the Downton Pippin. In a 

 Letter from Thomas Andrew Knight, Esq. F. R. S. &c. to the Secretary of 

 the Horticultural Society - - - - 316 



Scientific News - - - - - 317 



SUPPLEMENT 



