
• a. & n. from Snift. • (p. pr. & vb. n.) of Snift
Found on
http://thinkexist.com/dictionary/meaning/snifting/

The practice of momentarily opening a cylinder valve to remove moisture and dirt. There must be no possible source of ignition in the vicinity and the operator should wear eye protection and stand clear of the gas stream. Snifting must never be carried out on a hydrogen cylinder because spontaneous ignition can occur.
Found on
http://www.bocindustrial.co.uk/bocindustrial/technical/glossary/s.html
Snift'ing adjective & noun from
Snift .
Snifting valve ,
a small valve opening into the atmosphere from the cylinder or condenser of a steam engine, to allow the escape of air when the piston makes a stroke; -- so called from the noise made by its action. Found on
http://www.encyclo.co.uk/webster/S/133
No exact match found.