CONTENTS. 



On a Periscopic Camera Ohscura and Microscope . * 1 24 

 M. Figoier's new Process for depriving Vinegar and other 



Vegetable Liquids of their Colour 129 



Notice respecting some Experiments on Alcohol ; read lefore 

 the Edinburgh Institute 'id February \S13 .. .. 130 

 j4 Comparative Scale of the Thermometers of Celsius, or the 

 Centigrade, — Reaumur, — Fahrenheit, and IValker 136 

 Account of the late Earthquake at the Caraccas . . l6l 

 Description of a mechanical Instrument to work Addition of 



Numbers with Accuracy and Dispatch 1 66 



Remarks on Don Joseph Rodriguez's Animadversions on 



Part of the Trigonometrical Survey of England . . 178 



Description of a hanging Scaffold to be used in repairing 



or painting Outside IFalls of Houses 195 



Method of relieving a Horse from a Cart ivhen fallen doivn 



in its Shafts 196 



On the Removal of Impediments to the Acquirement of Vi' 



sion by Persons cured of Cataract 205 



Essay on the medical Effects of Climates . . 210, 255 

 An Investigation of the Properties of Lactic Acid . . 24 1 

 Critical Observations on Dr. Wollaston's stated Improve- 

 ment of the Camera Obscura and Microscope in the Ap- 

 plication of the Meniscus and two Plano-convex Lenses ; 

 proving their Inferiority to the double Convex Lens ge- 

 nerally used .. .. ., 247 



JW.Montgolfier's Process for making White Lead 253 



On the Aurora Borealis 263 



On Bread made from a Mixture of Wheat Flour and Po- 

 tatoes . . 2C5 



On Solids of greatest Attraction or Repulsion .. .. 268 

 On a Composition forming a Substitute for Portland Stone 



273 



Researches upon, the Heat developed in Combustion, and in 



the Condensation of Vapours 285, 43-4 



