held against the surface of the glass tube after the blade retracts from contact the paper is used to verify that the surface of the glass surface is dried by the blade in this trial when the blade was retracted from contract with the surface of the glass tube the paper turned dark which indicates a release of the bead of water from the blade this trial illustrates the functioning of blade such as blade 104 described above when a pad such as pad 112 is attached to the blade the pad is a 3 mm thick foam strip and is cut using a scalpel blade the pad is attached with double back tape to the blade and mounted as close to the edge of the blade as possible without interfering with the edge of the blade in this trial water is applied to the surface of the glass tube the pivoting blade holder swings the blade into engagement with the glass tube with sufficient pressure to dry the glass tube the paper slip is used to detect moisture on the surface of the glass tube after the blade retracts from the surface of the glass tube the paper indicated that the surface of the glass tube was dry this trial illustrates that the.