230 A Tribute to the Memory of 
nued, for many years, to feel a warm interest 
in the advancement of science; and to main- 
tain an occasional correspondence with per- 
sons highly eminent for their rank as philoso- 
phers, both in this and other countries.* His 
medical occupations had greatly increased, 
and, for a further interval of fifteen or twenty 
years, he had a share of professional employ- 
ment, which falls to the lot of very few. This, 
and the superintendance of some chemical 
concerns, prevented him from attempting 
more than to keep pace with the progress of 
knowledge. He was inno haste, however, to 
claim that exemption from active labour, to 
which advanced age is fairly entitled, and it 
was not till a very few years before his death, 
that he retired from the exercise of the medi- 
cal profession. 
The summers of the years 1834 and 1815 
* A considerable collection of letters to Mr. Henry from 
persons of this description has been preserved ; but the 
subjects of them have, for the most part, been long ago 
brought before the public by their respective writers. The 
letters are chiefly valuable to the family of the deceased, 
as unequivocal proofs of the respect and esteem, felt to- 
wards him by those who were best qualified to judge of his 
merits. Many of them are from learned foreigners, with 
whom he had enjoyed opportunities of personal om 9 
during their visits to Manchester. 
