MEETINGS OF SOCIETIES 129 
December 9.— “Spectroscopy. Applications to chemistry and astronomy.” 
December 16.— “Polarization, with some applications to chemistry and 
molecular physics.” 
January 6— “The exact laws of reflection and refraction and their 
bearing on the construction of optical instruments.” 
January  13.— “Optical properties of crystals.” 
January 20.— ‘The principle of interference and its explanation of vari- 
ous color phenomena.” 
January 27.— “The measurement of light waves and the theory of dif- 
fraction.” 
February 3.— “Some relations between light and electricity.” 
PEOPLE’S COURSE. 
GIVEN in codperation with the City Department of Education. 
Saturday evenings at 8 o'clock. Doors open at 7:30. 
Proressor BrapLeY StoucHuton of Columbia University,— a course of 
Jectures on metallurgy, illustrated by experiments and stereopticon views. 
December 5.— ‘The Uses of Iron and Steel in Machine Shops and Bridges 
and other great Engineering Structures.” 
December 12.— ‘The Rolling and Forging of Iron and Steel.” 
December 19.— ‘The Heat Treatment of Steel.” 
‘Tuesday evenings at 8 o'clock. Doors open at 7:30. 
Mr. Cuarwes M. Pepper, of the Department of Commerce and Labor, 
— illustrated lectures on ‘The Twentieth Century South America.” 
December 1.— ‘‘Argentine, the World’s Wheatfield.” 
December 8.— ‘‘The Vastness of Brazil.” 
December 15.— “‘Colombia and the Andes.” 
Children are not admitted to the lectures of the People’s Course, except 
on presentation of a Museum Member's Card. 
MEETINGS OF SOCIETIES. 
Public meetings of the New York Academy of Sciences and Affiliated 
Societies are held at the Museum according to the following schedule: 
On Monday evenings, The New York Academy of Sciences: 
First Mondays, Section of Geology and Mineralogy. 
Second Mondays, Section of Biology. 
