fiz - What does it mean?

Verb

“Why, do you know Margaret, I never hear the gallant captain talk, but I think of those small stone bottles one sees by the road-side, in the little green barrows on hot, dusty day. Fiz', '''fiz''', ' fiz they go, and only seem to be watching an opportunity to fly out in the face of that luckless wight who should be bold enough to cut their restraining wire.”