If you ever hear anyone refer to a jar with a disconnected underscore this is an excellent example. There are other jars that will look a bit different but this jar here has a true disconnected underscore. Note it isn't connected to the word Ball at all.

  A closeup view of the ghosted Perfect mason you will see on this Ball Improved varient Redbook #222-6. A re-worked mold that used to be a Perfect mason & now a Ball Improved. Circa:1915+

  Here is a closeup view of the ghosted Perfect Mason you will find on one varient of the Ball Perfection jar Redbook #269. This is a re-worked mold that used to be a Ball Perfect Mason. Circa:1914

  This is a picture of 3 jars to show what is referred to as a "bulge neck" jar. Some Ball jars have this style neck which you can see in the picture is is not straight and uniform but is fatter and bulged out to prevent the wire bail from moving upward. The first half gallon Sure Seal has a regular neck finish full wire twist bail. The other 2 jars have the bulge neck style.

  Click here for a close up view of the bulge neck

  This pic shows the detail of a hand blown jar with a ground lip. Notice how the surface looks rough and porous compared to the rest of the glass which is smooth. After the jar was blown and removed from the blowpipe it was taken to be ground on a stone wheel to make it smooth and clean off the burrs so a closure could be screwed on and the jar sealed. This is the best way to tell if a jar is hand blown or machine made. Many early machine made jars have bubbles in the glass and this isn't the correct way to determine how the jar was made. If in doubt take a look at the mouth of the jar and this will tell you...

  This is a picture of a machine made jar with a smooth lip. Notice how it is smooth and rounded and isn't rough looking as the pic above. Machine made jars started appearing in the late 1890's from Ball with the F.C. Ball machine, E.B. Ball machine, Ball bingham and then with the Owens machine they really started cranking them out. A smooth lip machine made jar will feel just like the body of the jar itself however some do have a few sharp places or feel a little jagged. You can see though there is a major difference in the way it looks and also the feel of it...

    Here are 2 photo's of base mold markings that a lot of people seem to mistake for a pontil mark. Pontiled jars are very old and date to pre-1860 or right around 1860 so your fruit jar better be pretty old to have a pontil mark. These designs on the base are merely valve marks from a particular machine and not pontil marks. Each machine has different looking marks and differ a little from jar to jar. The first pic is from the Owens machine and the second is from the F.C. Ball. Not pontil marks by no means. Most fruit jars you will find that are pontiled will have an iron pontil mark which a lot still have the residue left intact. These feel sandy in a way and have a pushed up base. I do not own a pontiled fruit jar but do have an early medicine bottle that has an open pontil. These pontiled bottles have very sharp scars from the rod being broken off after the bottle was finished and can be pretty crude and cut your fingers if not careful. You will notice the pontiled jar base looks a lot different then a machine made base above. Also the numbers on the base of a jar really have no importance as they just identify the mold used for that particular run of jars. However some people like to collect jars with #13 on them for the superstition as it is said many were broken for that reason. I don't think they are all that scarce as I find them on a regular basis.

  Click here to see an open pontil base

  This is a scan from Red book 8 showing the different style script you will find on a Ball jar which also can help date a jar. This will show the 3L Ball script along with dropped "A", undropped "A", dropped "R", with or with out underscore and so on. Of course any Ball jar with the 3L design is one of the earliest machine made jars from around 1895 to 1910. A Ball jar with a dropped "A" could be up till the early 20's. Jars with no underscore are mainly from the 1920's and the underscore was added in the 1930's. The attached underline is most likely a jar mold from the 1920's being used in the 30's hence the added line. A Ball with the ghosted 3rd L loop is around 1910 when Ball switched to the 2 L style. These I have seen most common on Sure Seal jars and some Ball Mason jars. Dropped "R" and undropped "R" jars refer to the Ball Improved jars with the undropped "R" version's being the earliest. There are a few varients that are odd so if you read this and have something different e-mail me and I'll help you out if I can...