Ixii PROCEEDINGS. 
Watson L. Bisuop, Esq., read a paper on “ The Star-nosed Mole,” 
and exhibited specimens of the young. (See Transactions, p. 348.) 
Pror. J. G. MacGrecor, D. Sc., communicated a paper ‘ On the: 
use of the Wheatstone Bridge with Alternating Currents.” 
SrxtH Orpinary MEETING. 
City Council Chamber, Halifax, 5th April, 1901. 
The PresipEntT in the chair. 
A communication was read from the Encrngers’ Socrtety or WESTERN 
New York, Buffalo, offering the use of the society’s rooms to any mem- 
ber of the Institute who may visit the Pan-American Exposition. The: 
SECRETARY was directed to make a suitable reply. 
The following paper was communicated :— 
THe Rare Eartrus: THeir Screntiric IMPORTANCE AS REGARDS THE: 
Periopic Law.—By W. H. Macss, Pa. D, High School, Parrs- 
boro, N.S. 
AT a meeting of scientists, it is, of course, unnecessary for me to- 
apologize for the fact that the subject of my paper is one in which the: 
general public takes no interest. There are few, even among chemists, 
who take more thin a passing interest in the so-called Rare Earths. You, 
however, who are seekers after truth, are aware that even in what might. 
seem the most despicable of materials there are startling discoveries await- 
ing the patient investigator who will delve into the hidden mysteries: 
and bring to light truth, not only of rare interest to the scientific circle 
whose sympathies he enjoys, but uf advantage to the general public which, 
though impatient of the labor and details, is ever ready to avail itself of,. 
and to liberally reward, results, 
The term Ruire Earths, is, if not a misnomer, at least misleading, 
since there are earths or oxides not classed in the group which are as rare,. 
if not rarer, than these themselves. The usually accepted definition of 
a rare earth is ‘‘a substance precipitable by oxalic acid from a weakly 
acid solution and having the formula R, O, in which R stands for the 
element of the oxide.” This definition, however, if rigidly adhered to, 
excludes Ce., Th. and Zr., which are usually ranked with the rare earths. 
and, being applied ever so generally, would place Tl., Ga., Ge., In., etc., 
among the ordinary or at least not rare earths. 
