Vlll CONTENTS OF VOL. XXI. 



Page 

 Messrs. W. Francis and H. Croft's Notices of the Results of the 



Labours of Continental Chemists (continued) 446 



Dr. Draper on a new Imponderable Substance, and on a Class 



of Chemical Rays analogous to the Rays of Dark Heat .... 453 

 Mr. R. Hunt on Thermography, or the Art of Copying En- 

 gravings, or any printed Characters from Paper on Metal 

 Plates ; and on the recent Discovery of Moser, relative to the 



formation of Images in the Dark 462 



Mr. Hopkins on the Elevation and Denudation of the District of 



the Lakes of Cumberland and Westmoreland 468 



Proceedings of the Royal Astronomical Society 477 



London Electrical Society 484 



Cambridge Philosophical Society 485 



Use of Sulphate of Ammonia in Agriculture 488 



Chloride of Gold as a Test of certain Vegetable Alkalies .... 489 

 Non-Decomposition of Vegetable Alkalies by exposure to Fer- 

 menting Bodies ■ , 490 



Preparation and Composition of Pepsin 491 



Action of Chlorides on some Mercurial Compounds, by M. 



Mialhe 492 



On a new Mode of forming Ammonia, by M. Reizet 495 



Meteorological Observations for October 1842 495 



Table 496 



NUMBER CXLL— SUPPLEMENT TO VOL. XXL 



Prof. Marianini on the Currents produced by the Actuation or 



Induction of instantaneous Electric Currents 497 



Proceedings of the Royal Astronomical Society 510 



Royal Irish Academy 532 



Geological Society 540 



Index 562 



PLATE. 



I.— Linear Solar Spectra with their corresponding Tithonographs ; illus- 

 trative of a paper by Dr. Dkaper. 



Errata. 



Page 43, line 13 from the bottom,/or (*+T)' read e (*+ T )\ 



44, — 3, put sign + before \/ . 



55, — 7 from the bottom, instead of " M. Catalan," read " Pro- 

 fessor MacCullagh." 

 176, line 13,/or quina read citichonia. 

 473, line 4 from the bottom,/or Penim read Penine. 

 529, line 2 from the bottom,/or node read note. 



