44 TRANSACTIONS OF THE [Nov. 24, 
metals, but the silver compound is not blackened by light; the 
mercurous, copper, and ferrous salts are explosive. 
Advantage is taken of the insoluble silver salt to prepare the 
acid ina pure state ; boiled with dilute sulphuric acid it yields 
hydrazoic acid. An aqueous solution containing 27 per cent of 
the gas is much heavier than water and sinks to the bottom of 
the vessel into which it is poured. The solution yields white 
clouds with ammonia, just like hydrochloric acid. Prof. Cur- 
tius plans to build up an entire new series of nitrogen compounds 
of greatest interest to the chemical world. 
Dr. Bolton spoke of the great importance of the discovery of 
the new strong acid from industrial, analytical, and physiological 
points of view. 
November 24th, 1890. 
STATED MEETING. 
The President, Dr. NEWBERRY, in the chair. 
About two hundred persons present. 
The minutes of November 17th were read and approved. 
Dr. Boron announced that a joint meeting of the Academy 
and the American Folk-lore Society would be held at Columbia 
College, Friday evening, November 28th, at 8 o’clock. 
PRESIDENT NEWBERRY announced the opening of the Public 
Lecture Course of 1890-1891, and introduced Mr. FREDERICK H. 
CuaPin, of Hartford, Conn., who spoke on the 
CLIFF DWELLINGS OF THE MANCOS CANONS. 
The lecture was highly novel and interesting, and was illus- 
trated by a large number of lantern views taken by the lecturer. 
At the close of the entertainment a vote of thanks was unani- 
mously given Mr. CHAPIN. 
