X CONTENTS. 



Page 

 Mr. J. C. G. Kennedy on the Influence of Discoveries in Science and Works of 

 Art in developing the Condition of a People, as indicated by the Census 

 Operations of the United States 108 



Dr. Edw. J. Tilt on the best Means of ascertaining the Number and Con- 

 dition of the Infantile Idiots in the United Kingdom 109 



Dr. W. Whew ell's Mathematical Exposition of some Doctrines of Political 

 Economy 110 



MECHANICAL SCIENCE. 



Capt, CARPENTER on the Duplex Rudder and Screw Propeller , ,. 110 



Mr. Alexander Doull's proposed Railway Communication from the Atlantic 



to the Pacific in the Territories of British North America Ill 



Mr. Fairbairn on the Construction of Iron Vessels exposed to severe strain... 113 

 Mr. Charles May on Railway Chairs and Compressed Wood Fastenings 114 



on the Application of Chilled Cast Iron to the Pivots of 



Astronomical Instruments 114 



Mr, James Nasmyth's Description of an Improved Safety Valve 115 



on a Direct Action Steam-Fan for the more perfect Ven- 

 tilation of Coal Mines 116 



on an improved Apparatus for Casting the Specula of 



Reflecting Telescopes Il6 



Mr. Joseph T. Price on a Method of Condensing Steam in Marine Engines, 

 at present emploj-ed in several Steam Vessels in the Bristol Channel 116 



Mr. Richard Roberts on Mechanism to explain the Pendulum Experiment... 117 



Prof. P. Smyth on a simple method of applying the Power of Wind to a Pump, 

 for the purpose of Irrigation, as put into practice at the Cape of Good Hope 118 



Mr. James Thomson on an Improved Modification of the RcsciToir for Gold 

 Peas 118 



ADVERTISEMENT. 



The Editors of the preceding Notices considei* tbemselves responsible 

 only for the fidelity with which the views of the Authors are abstracted. 



