Glenda, I hope the following is of some help. Ink codes on the glass stems are generally quite confusing. Each factory seemed to have its own way of marking. However, within National standardizing started about 1912 and in some cases it is possible to determine lamp watts, voltages, lamp factory and date of manufacture. In your case the following is what I believe to be true: The "25" refers to lamp watts. The "a2" is the lamp voltage, which,in your case, is 112 volts. The "7UD" probably gives the factory I.D.; I don't know how to interpret that code. At one time the number "7" referred to a factory in Oakland, CA but I wouldn't want to make that assumption about your lamp. The date "Nov 8, 1904" probably refers to the date a patent was granted to Alfred Swan (brother of Sir Joseph W. Swan) for the design of the base. That patent covered the use of the black glass insulator between the brass parts. The insulator prior to the black glass was porcelain. I would guess that your lamp was manufactured about 1913-1915.
