This month’s History Mystery historical postcard was sent from Knightsen to Oakland in 1910 and saved as one of more than 800 postcards in a collection found by local resident John Gonzales in the walls of his property in Knightsen.

Water damage to the house required the replacement of the original lath and plaster interior wall treatment. Behind the wall, hidden between the studs, were two scrapbook collections of postcards spanning 40 years of correspondence. The entire collection was appraised and donated to the East Contra Costa Historical Society in 2008.

Of the hundreds of cards, historian Carol Jensen is asking readers about a postcard that features a little girl with soft blond curls holding onto a clock while standing under a large horseshoe decorated with pink roses. The illustration is accompanied by a message written in glitter-covered glue.

Jensen said this divided-back card, postmarked in October of 1910, is an early example of the quality, embossed colored, trade postcards that were popular in the first decade of the 20th century. The United States postal service changed postal regulations to allow divided back postal cards in March of 1907. Great Britain led the way in 1902, France in 1904, and Germany from 1905.

This German color lithographic postcard, which was distributed in the United States by United Art Publishing, is representative of its kind. Typically blank cards were printed in Europe and hand colored for local use by the application of a slogan in glitter and glue, usually incorporating the name of the city.

Readers are asked to solve the message on the back, which was sent to Adeline Knight. The message reads: “We had a very pretty card from Amy yesterday saying they had got into Coalinga in a great big auto and was going to Fresno to get a supply of winter clothes. Maybe you heard from her too. There’s no news from home. Write soon! Love, Sister Essie.”

Then there is an afterthought that is scrawled at the top of the card, which reads: “It’s too bad that they didn’t spell Kn. right. Sent George a card like this – only blue.”

Knightsen was founded by George Knight, who bought the land now occupied by the town in 1883. The card could be correspondence between members of George’s family, but Jensen wants to know for certain, and would like any additional information locals might have about the card, its message or the people whose name are on it. The reader who provides the most information will win an annual membership to the California Historical Society. Responses should be e-mailed to Jensen at historian@byronhotsprings.com.