Using physical, manufacturing related diagnostic features, most utilitarian bottles can usually only be accurately placed within a date range of years i. The four-piece mold is a variation of the three-piece mold with two body halves instead of one; this mold type is discussed in the box below. Multi-sided dip mold bottles pictured below may likely have been made from multi-part dip molds, though side seams showing the interface between the mold pieces are rarely seen, being either masked by the corner edges of the bottle or the bottle body was fire polished to the point that seams are unrecognizable.
One noted example, which was known to have been made in the midth century, was dated - a date that pertained to the implementation of certain wine production laws Jones ; Van den Bossche Upon contact with the very hot glass on the end of the blowpipe some of the water turned to steam. One of the longest running "myths" in the world of bottle dating is that the side mold seam can be read like a thermometer to determine the age of a bottle. Appealing though this notion is, the large majority of molds used to produce bottles during the era covered by this webpage through the s were made of various metals, or in the earlier years, fired clay Van den Bossche Part II - pages , pages , pages , pages , pages