A heavy snowfall, bitter winds, and icy sidewalks failed to deter an enthusiastic audience from nearly filling the Morgan Library’s Gilder Lehrman Hall on January 21, when the Boston Early Music Society continued their New York series with a concert by the London Haydn Quartet with Eric Hoeprich, the great historically informed clarinettist and instrument-maker, who were offering a program of Haydn, Beethoven, and Mozart. The bare white basement space that serves as the lobby of the hall is hardly the most attractive part of one of New York’s most elegant institutions, but its heating was welcome enough, and once one enters the auditorium, one can enjoy some warmth of design and acoustics as well.