My friends - As I continue my trek here in the JP area, I want to drop by to bring you the next installment in "The Best of" series that I am using while I am away from home. Tonight's reposting has to do with the "8870 Formula". I will be in Fulton, Graves, Hickman and McCracken counties tomorrow. I'll check in again tomorrow evening. -B ============================================================ ========== All of us who have been involved in genealogical research for very long at all will have run into grave markers in cemeteries which may read something like this: John J. Parkenfarker Died 15 July 1877 Age 75 years, 10 months, 3 days How do you find the exact date of John's birth, without sitting down and placing marks on a piece of paper and "counting back" until we reach the date? Some of you may have run into a technique popularly known as "The 8870 Formula", which basically has you line up the date of death in this order: 18770715, then subtract from that 751003. When you have that result, you subtract the constant figure 8870 and the result should be your exact date of birth, such as 18010842(in this case) - born August 42, 1801??? No, I think not. This old formula only works in certain cases, and, hopefully, by now, almost everyone knows it is faulty and stays away from it. So, what CAN you use, in lieu of doing it all "manually", so to speak, by counting backward? Many of us use the computer to make these calculations, but here is another approach, and we'll use the case of the Parkenfarkers grave marker as an example: Show the death date in this order: 15-7-1877 Subtract the age, in this manner: 3-10-75 You cannot subtract "10" from "7", so borrow 12 months from the year of death(1877), making the year 1876 and the month 19. So you now have the following: 15-19-187 Subtract 3-10-75 Subtracting from the right, we find that the year of birth was 1801 (1876 minus 75), and that by subtracting 10 from 19, we see that the month was "9", or September, and the day of birth was the 12th - September 12, 1801. That formula works properly. If you have to "borrow" days from months, always use 30 days, even if the month had 31. I used this approach for some years, before computers. I used to check it each time I used it, but, after about 50 checks, I detected no errors. It takes a few tries to get used to it, but after you do, I think it is unlikely that you will return to calculating birth dates by the hand-count method. Of course, you will want to be wary of birth years back in the early 1700's when the calendar was changed, but we do that in any event. ============================================================ =======