150 Prof. A, de la Rive’s Memoir of 
low temperatures. We may notice two. important memoirs— 
one upon the explanation of certain optical illusions produced 
by bodies in motion, the other describing some new acoustic 
figures proceedi m the vibrations of the stratum of air in 
contact with the surface of vibrating plates. His alepent sine 
y 
above 32° F.), followed into its consequences as it has been 
by Tyndall, has had a much grea 
Let us now dwell for a few moments upon some researches 
of longer duration, the publication of which preceded, and 
also in great part accompanied, his great works on ec nee 
i Parada; unds 0 
it crystallizes in little prisms : i ; 
by comes he direct action of the sun bicarbonated hydro- 
gen gas with a large proportion of chlorine. The other con- 
