Found the following hamletworks.org entries referring to line 30
View Commentary Note for 27
27
Bar. Say, what is Horatio there?
1.1.19
View Material Textual Note for 29
29
Bar. Welcome Horatio, welcome good Marcellus,
1.1.20
View Commentary Note for 30
30
{Hora.}
<Mar.>
What, ha's this thing appeard againe to night?
1.1.21
View Immaterial Textual Note for 30
30
{Hora.}
<Mar.>
What, ha's this thing appeard againe to night?
1.1.21
View Material Textual Note for 30
30
{Hora.}
<Mar.>
What, ha's this thing appeard againe to night?
1.1.21