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POPULAR SCIENCE REVIEW. 
Roux’ apparatus ; the first obliquely-strung upright piano patented by Wor- 
num in 1811 ; models of ancient Egyptian pipes ; Tyndall’s apparatus ; and 
a stand of apparatus illustrating the progress of HSolian principles. In 
Section 7, a Light/’ are : Sir David Brewster’s early stereoscope ; a camera 
obscura of Sir Joshua Reynolds ; the original form of Brewster’s kaleido- 
scope made in 1815 ; spectroscopic apparatus used by Sir John Herschel ; 
a fine collection of spectroscopic instruments by Browning and others : 
Wheatstone’s polar clock ; Crookes’ radiometers ; the first photograph taken 
on glass by Sir John Herschel ; the second daguerreotype, a view of the 
Palais d’Orsay, taken by M. Daguerre in 1830 ; Herschel’s experiments on 
the action of light on different kinds of salts ; and the results of Dr. Forel’s 
experiments in the Lake of Geneva on the penetration of the sun’s rays in 
the waters of the lake. In Section 8, “Heat,” may be noticed the original 
Lavoisier calorimeter, the apparatus used by Professor Tyndall in his re- 
searches on the absorption of radiant heat by gases and vapours; Wedg- 
wood’s pyrometer; a Musschenbroek’s pyrometer; Siemens’ pyrometer; 
apparatus used by Tyndall, De la Rive, and others ; and a very fine collec- 
tion of thermometric instruments. 
