LIST OF ILLUSTRATIONS. 
Plates 1 to 3.—Mr. H. M'Leod and Lieutenant G. S. Clarke on the Determination 
of the Rate of Vibration of Tuning-Forks. 
Plates 4 and 5.—Professors W. E. Ayrton and J. Perry on the Contact Theory of 
Voltaic Action. 
Plates 6 and 7.— Mr. W. Bevan Lewis on the Comparative Structure of the Cortex 
Cerebri. 
Plates 8 to 10.—Messrs. W. De La Rue and H. W. Muller on the Electric Discharge 
with the Chloride of Silver Battery. 
Plates 11 to 13. —The Earl of Rosse on some recent Improvements made in the 
Mountings of the Telescopes at Birr Castle. 
