Chemistry and Physics. _ 391 
ratus and its uses, to give more fully the leading points of the 
that this outline of the theory, thus incidentally given, will 
prove not unacceptable to such instructors as may not have at 
hand the original works; and that this new piece of apparatus 
may contribute somewhat toward imparting a clearer under- 
standing of the phenomena of waves. 
The apparatus has been patented, and is manufactured by 
Messrs. E. S. Ritchie & Son, the well known philosophical in- 
strument makers, of Boston, Mass. L. 
SCIENTIFIC INTELLIGENCE. 
I. CHEMISTRY AND PHYSICS. 
