… stoppers (of cork, glass, etc.), glass balls, metal caps, screw caps (of metal or plastics), or special devices (e.g., … of these containers, however, may be closed by corks or screw stoppers. Like bottles, these articles may be …
… and unloaded paper of good quality in sulphuric acid for a few seconds. The action of the acid converts some of the … by testing their resistance to water. When soaked for a few minutes vegetable parchment tears only with difficulty …
