2 That to a steadfast star his course has bent, 3 When foggy mists, or cloudy tempests have 4 The faithful light of that fair lamp blended,
blended > rendered turbid, obscured
5 And covered heaven with hideous dreariment,
dreariment > gloom
6 Upon his card and compass firms his eye
card > chart firms > fixes
7 (The masters of his long experiment),
masters > teachers, preceptors experiment > experience, practical knowledge
8 And to them does the steady helm apply,
to > [according to] apply > steer