Jolly’s spring balance

a jolly dog

spring balance system

spring balance scale

spring balance safety valve

spring balance

Jolly`s spring balance

hanging spring balance

balance spring stud screw

balance spring stud

balance spring

the jolly Roger

spring roll balance

Jolly’s stochastic model

Jolly’s photometer

jolly’s balance

jolly’s apparatus for gas analysis

Jolly‘s photometer

Jolly Roger