This is part of Hasse's "Mea Tormenta, Properate".
I think the one on the second staff is some sort of repeat sign, from the research I've been able to do, but I have no idea what the one on the third staff is for. I can provide more musical context if that's necessary.
The second staff is a violin part and the third staff is a viola part, if that's helpful too.
Figure 1. Three staffs of handwritten music. The top staff is a treble clef in the key of B flat. The second staff is also a treble clef in the same key. It has no notes and just contains a cesura/simile like symbol in the middle of the staff. The third staff is an alto clef in the same key. This staff contains a symbol that's like a backwards c, two parallel lines, and a small s. The center of the symbol is on the second line of the staff.