Many of the early sewing machines were powered by a treadle mechanism. The treadle was operated by pressing down on it with a foot, or both feet, to cause a rocking movement. This movement spins a large wheel on the treadle frame, connected by a thin leather belt to a smaller driving wheels on the sewing machine.
null. adj. 1. Having no legal force; invalid: render a contract null and void.2.ull. adj. 1. Having no legal force; invalid: render a contract null and void. 2.
An XML value will never be returned from a document as null. It is either an empty string or a does not exist error. When it is an empty string, an error may occur for conversion of certain types, for example, fields specified as an integer type when building rules. The Business Rule Composer does not allow you to set a field to null or to set the type of a field to object.