On further research, Bokkelen was in the Army until 1861. He left the field service in 1853 for the Recruiting Service, and then actually did move to the Quartermasters, which looks to be how he got cashiered. This is from Cullum's Register. His full name seems to have been William Kemble Van Bokkelen
a.
Military History. — Cadet at the Military Academy, July 1, 1839, to July 1, 1843, when he was graduated and promoted in the Army to Bvt. Second Lieut., 7th Infantry, July 1, 1843.
Served: in garrison at Ft. Pike, La., 1843, — Ft. Morgan, Ala., 1843, — Pensacola harbor, Fla., 1843‑44, — Baton Rouge, La., 1844‑45, — and
(Second Lieut., 3d Infantry, Nov. 26, 1845)
Ft. Pickens, Fla., 1845; in Military Occupation of Texas, 1845‑46; in the
(Transferred to 7th Infantry, June 27, 1846)
War with Mexico, 1846; on Recruiting service, 1846‑47; in the War with Mexico, 1847‑48, being engaged in the Battle of Contreras,
(Bvt. First Lieut., Aug. 20, 1847, for Gallant and Meritorious Conduct
in the Battles of Contreras and Churubusco, Mex.)
Aug. 19‑20, 1847, — Battle of Churubusco, Aug. 20, 1847, — Battle of Molino del Rey, Sep. 8, 1847, — and Operations before and Capture of the City of Mexico, Sep. 13‑14, 1847; as Quartermaster, 7th Infantry, Jan. 17, 1848, to Sep. 10, 1850; in garrison at Jefferson Barracks, Mo., 1848‑49; in Florida Hostilities against the Seminole Indians, 1849‑50; in garrison at Jefferson Barracks, Mo., 1850, — Ft. Leavenworth, Kan.,
(First Lieut., 7th Infantry, July 16, 1850, to Jan. 2, 1858)
1850, — and Jefferson Barracks, Mo., 1850‑51; on frontier duty at Ft. Washita, I. T., 1851‑52; on Recruiting service, 1852‑53; and on Quartermaster
(Captain, Staff — Asst. Quartermaster, July 28, 1853)
duty, in the Quartermaster-General's office, Washington, D. C., 1853, — Tampa Bay, Fla., 1853‑54, — Texas, 1854‑57, — Florida Hostilities, 1857‑58, — and Ft. Union, N. M., 1858‑61.
Cashiered, May 8, 1861, for Misapplication of $225 of Public Funds.
Civil History. — In Mercantile pursuits, New York city, since 18??
Died March 25, 1907, at Brooklyn, N. Y.: Aged 85.
Buried, Green-Wood Cemetery, Brooklyn, NY.