Miss Knowlton is known to have had spent the summer of 1875 with her pupils at the Glen House.

BANGOR (Maine) DAILY WHIG COURIER, Wednesday, October 20, 1875, p. 4. ART AND ARTISTS.
“Helen M. Knowlton spent the summer with several of her pupils at the Glen House White Mountains, and she contemplates building a studio there next season.”

She exhibited at the AMC Exhibition of 1877 eight works. They were titled:

Pasture at Base of Mt. Washington.
Mt. Kearsarge (Carroll Co.), from North Conway Intervales [sic].
Mt. Washington from the Glen House.
Mt. Madison.
Toll House and Mt. Adams.
Mt. Adams at Sunset.
Burning Woods — Mt. Madison.
Mt. Washington from the Glen.

Please contact the authors if you have any information on this artist

Reference
Catalog titled “Appalacian Mountain Club, Paintings and Sketches, Exhibited March 14, 1877.”
Independent research by Charles Vogel and Allen Vogel