CONTENTS. ▼U 



Page 



Mr. A. R. Catton on the Laws of Symmetry of Ciystalline Forms 10 



's contribution towards the expression of the angle between 



the Optic axes of a Crystal in terms of the angles between the faces 10 



on the Theory of Double Refi'action, with special reference 



to the influence of the Material Molecules on the propagation of Light in 



Crystals 10 



Mr. A. Claudet on a Mechanical Means of producing the differential motion 



required to equalize the focus for the different planes of a solid 10 



's New Fact of Binocular Vision 10 



's Photographic Portraits obtained by Single Lenses of Rock 



Crystal and Topaz 10 



Mr. J. Clerk Maxwell on a Real Image Stereoscope 11 



Dr. J. Moffat's Experiments on the Luminosity of Phosphorus 11 



Heat. 



Mr. R. RxJSSELL on some Deductions by Dr. Tyndall from his recent Experi- 

 ments regarding the Radiant and Absorptive Properties of Vapour in the 

 Atmosphere 11 



Mr. C. Wheatstone on a New Telegi-aphic Thermometer, and on the Ap- 

 plication of the Principle of its consti-uction to other Meteorological In- 

 dicators 11 



Electbicity, Magnetism. 



Mr. William Hooper on the Electric Induction of Mr. Hooper's Insulated 

 Wires, compared with Gutta-Percha Insulated Wires, for Telegi-aphic 



Cables 13 



Mr. William Ladd on a new form of Dynamo-Magnetic Machine 13 



on a Magneto-Electric Machine 14= 



Dr. T. L. Phipson on the Phenomena which occur when Magnetized Steel is 

 dissolved in Acids 14 



Mr. T. Ste^'enson's Notice of a proposal to illuminate Beacons and Buoys 

 by Electricity, conveyed through Submarine Wires connected with the 

 Shore. With a description of the Induction-Spark Apparatus used for this 

 pm-pose in the first experiments made for the Northern Lights Board, also 

 the Electrical Apparatus recently designed for the Northern Lights, by 

 C. W. Siemens 14 



Sir W. Thomson on a Self-acting Electrostatic Accumulator 16 



— on a Series of Electrometers for Comparable Measiu-ements 



through Great Range 16 



on a Unifonn-Electric-Current Accumulator 16 



on Volta-Convection by Flame 17 



on Electric Machines founded on Induction and Convection 18 



Meteoeologt. 



Sir David Brewster's Notice respecting a Haystack struck by Lightning . . 19 



Mr. Alexander Brown's Observations of the Rainfall at Arbroath 19 



Senhor Capello's Comparison of the Kew and Lisbon Magnetic Curves during 

 the Disturbance of February 20-25, 1866 20 



