The inscription in President Lincolns watch, i.e. "Jeff Davis" and the inscription of L.E. Gross, to me matches in style or hand writing; so I'm assuming he wrote "Jeff Davis". I found on the 1860 federal census from Baltimore, Maryland, a Louis Gross, age 19, male, occupation Clerk, born in Maryland living with a Mr. Joseph Walter, male, age 36, Watch Maker, born in Maryland, total assets- $14,000 (thats a lot for a watchmaker, must of had a big business).
1. I found a Louis Edward Gross, born 1841 in Maryland, Father- Jacob Gross, b. 1809- and mother Rachel Haslitt, b. 1813-1849. Brother and sisters listed on family tree.

2. On the 1850 Federal Census I found "Lewis" Gross age 9 living with his father Jacob (age 41- Tea Dealer) in Baltimore, Maryland, with his brothers and sisters listed in a family tree for item (1.)

3. On the Civil War Soldiers and Sailors system I found no Gross' by any of the names given in the Union Army in Maryland or Confederate, but I found three names that match Louis/Lewis' brothers names in the 16th Virginia Cavalry, John, Joseph and William H. Gross. I also found two men with the same names as his brothers in the 42nd Virginia Infantry, Willima H. and John Gross.

His brother Joseph J. Gross, born 1835, in Maryland, full name Joseph Jacob Gross died in St. Louis, Missouri in 1907.
His brother William H. Gross, born 1837, in Maryland, died in 1898, in Baltimore.
His brother Alfred G. Gross, born 1839, in Maryland, died in 1921.
His brother Mark S. Gross, born 1843, in Maryland, died in 1896
His brother Jacob Gross, born 1845, in Maryland, died in St. Louis, Missouri, in 1916.
His brother Edward De Loughery Gross, born 1855, died in 1921.
His brother Charles Borromeo Gross, born 1859, died in 1911.
He had six sisters as well.

Louis Edward Gross, died on July 6, 1870.

Mr. Joseph Walter is listed on the Baltimore, Maryland Federal census of 1880 as keeping a jewelry store east of Eutaw Street. His business is listed in the 1879 Baltimore Directory as Joseph M. Walter, Jeweler, 85 N. Eutaw St.

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David Upton