m 



Monday, 17th April 1854. 



PAQU 



Notice of the Completion of the Time-Ball Apparatus. By 



Professor C. Piazzi Smyth, .... 238 



On the Mechanical Energies of the Solar System. By Profes- 

 sor William Thomson, .... 241 



Monday, Ist May 1854. 



On the Action of the Halogen Compounds of Ethyl and Amyl 

 on some Vegetable Alkaloids. By Henry How, Assistant 

 to Professor Anderson of Glasgow, .... 244 



On the Mechanical Value of a Cubic Mile of Sunlight, and on 

 the possible density of the Liuniniferous Medium. By 

 Professor W. Thomson. ..... 253 



Account of Experimental Investigations to answer questions ori- 

 ginating in the Mechanical Theory of Thermo-Electric 

 Currents. By Professor W. Thomson, • . . 255 



Dynamical Theory of Heat, Part VI. continued. A Mechanical 

 Theory of Tliermo-electric Currents in Crystalline Solids. 

 Hy Professor W. Thomson, ..... '255 



On the Structure of Diatomacea. By E. W. Dallas, Esq. . 256 



Donations to the Library, .■..•• 259 



