16 
clusive) shows that the temperature during that time did not 
vary much, as the mean, for the sixteen years, is 52.60°, giving 
eight above and eight below the mean, anda range of 7° only ; 
1859 having the highest mean (55.66°) and 1868 the lowest 
' (48.67°). The year 1869 was 1.1° below the average; the 
inaximum of 1869 was nearly that of 1855; the minimum 
was greater than of any in the series, being 85° above zero, 
while 9 ofthe years it was below, and in 1866 it was 138° be- 
low, and in that year also the thermometer rose to 98.8°, the 
highest in the series. 
He also read from abstracts of the temperature, &c. kept by 
C. Bogert, in New York city, from 1816 to 1858. 
May 9, 1870. 
The President in the chair. Twenty-five persons present. 
Mr. R. Dinwiddie exhibited a photograph of Sir James 
Young Simpson, recently deceased, and made some remarks 
on his contributions to Medical Science. 
Prof. Chas. A. Seely read a paper 
ON THE CONSTITUTION OF AMMONIUM-AMALGAM. 
He began by referring to its original discovery in 1808, by 
Berzelius and three other chemists, almost simultaneously. 
Davy’s reduction of Potash and Lime, by means of the 
Galvanic battery, whereby the metallic base of those sub- 
stances was demonstrated, preceded this presumed discovery 
of Ammonium-Amalgam, and probably led the way for other 
researches in this direction. Berzelius on this discovery of 
his, founded the Ammonium radicle theory, which at the 
present time is very generally accepted. Prof. Seely stated 
that he differed in opinion from most chemists as to the 
constitution of this Amalgam; he thought that the gases 
