110 MEMOIR OF THE LATE DR. HENRY. 
the profession became evident, and he was 
permitted, in the year 1805, to return to the 
University, where he received in 1807, the di- 
ploma of ‘ Doctor in Medicine.” 
The period intervening between his two aca- 
demic residences, though passed in the engross- 
ing occupations of his profession, to which was 
added the superintendence of a chemical busi- 
ness, many years before established by his father, 
was yet marked by several important contribu- 
tions to science. In 1797, he communicated to 
the Royal Society, an experimental memoir, the 
design of which was to re-establish,—in opposi- 
tion to conclusions drawn by Dr. Austin, and 
sanctioned by the approval of Dr. Beddoes and 
other eminent chemists,—the title of carbon to 
be ranked among elementary bodies. His proofs 
were derived from the electrization of an impure 
carburetted hydrogen gas: but it is needless to 
particularize the experiments, since in a subse- 
quent paper, he made known a source of fallacy, 
which had vitiated their results. They have 
value therefore, chiefly as suggesting encourage- 
ment to the young, by showing that Dr. Henry 
had to pass through a stage of tentative initia- 
tion before reaching the consummate skill, 
which afterwards distinguished him in that most 
delicate province of chemical research. 
