jectured to be peroxide of potassium, would furnish pure oxygen 
Ruschenberger. | 430 [Feb. 15, 
instruction of that eminent medical teacher and surgeon nearly 
four years. He had associated with him, in teaching his large 
class of students, several assistants. His office was a two-storied 
house, on the north side of Library street near to Fourth street. 
Tn it were a students’ reception-room, a laboratory and a lecture. 
room, and, in the rear of the house, a dissecting-room. 
In Dr. Hewson’s private medical school Dr. Franklin Bache 
taught chemistry. He appointed young Bridges his assistant 
very soon after he began his medical studies. In this capacity 
he served Dr. Bache through many years, in the courses of 
chemical lectures delivered by him in the Franklin Institute, 
in the Philadelphia College of Pharmacy, and at the Jefferson 
Medical College. This practical training made him an expert 
chemist and an admirable teacher of chemistry. 
His close attention, habitually given to whatever he might 
be doing, qualified him in a high degree to assist the lecturer ; 
on tg’ In May, 1827, upon pouring water into an iron 3 
mercury flask, which had been used for obtaining oxygen from 
nitre, for the purpose of washing it, he noticed a lively effer- 
vescence. He proceeded at once to investigate the nature of 
the gaseous matter, and found it to consist of oxygen of a purity 
of ninety-five per cent, as he ascertained by Dr, Hare’s accurate 
sliding-rod endiometer. He observed the same phenomenon, 
November 27, at the Franklin Institute, and found in this 
instance that the oxygen contained only one per cent of im- 
purity. He suggested that this residuum, which Dr. Hare con- 
to the experimenter without trouble. He was anticipated in 
this discovery. Mr. Richard Philips, of London, had made the 
same observation and given the same rationale of the phenome- 
non, an account of which he published in the Annals of Phi- 
losophy, for April, 1827. Nevertheless, Dr. Franklin Bache, 
published in the North American Medical and Surgical Journal, 
for January, 1828, a note of the observation of “Mr. Robert 
Bridges, student of medicine,” on the “ Residuum of Nitre after 
exposure to red heat,” 
