Individual Details

Cyrus B. Comstock graduated from West Point, 1855; rose to the rank of colonel and brevetted brigadier-general and major general of volunteers. He was the senior engineer at the surrender of Vicksburg. He married 3 Feb 1869, Elizabeth Blair. Their only child, Elizabeth Marion Comstock, was born 5 Aug 1872 and died 4 days later. [NEW ENGLAND FAMILIES GENEALOGICAL AND MEMORIAL, Series 1, William Richard Cutter.]

New England Families Genealogical and Memorial: Volume IV, Pp 1980-1
"He married, February 3, 1869, Elizabeth Blair, born April 25, 1841, died August 6, 1872, daughter of Montgomery Blair. and granddaughter of Francis P. Blair Sr, Child; Elizabeth Marion, born August 5, 1872, died August 9, 1872."

Ship's Passenger Lists on Ancestry.com
Theodore Cook, Master of the Steamship "Etruria" sailed from Liverpool, arriving in New York, 5 Dec 1887. One of the passenger was Lieut. Col. C. B. Comstock. He was departing England, but stated neither his occupation, nor his native country. He gave his age as 54.
Sailing on "The City of New York", arriving 9 Sep 1892 in New York City. C. B. Comstock, occupation listed as "General", Age 61; from London to Massachusetts, departed from Liverpool
New York City, Arrival 11 Jul 1896, the "Campania". C. B. Comstock, occupation "Officer", age 65, citizen of the U.S.A.

Found in an Ancestry Family Tree:

Brevet Brigadier General Cyrus B. Comstock
Born Massachusetts. Graduate UMSA 1855. Comstock served in many campaigns during the Civil War, including the siege of Vicksburg and the battles of Fredericksburg, Chancellorsville, Wilderness, Spotsylvania, Cold Harbor, Petersburg, Fort Fisher and Mobile. He served as General Ulysses S. Grant’s secretary.

After the war, he was superintending engineer of the geodetic survey of the Northern and Northwestern Lakes and later for the progress of the Eads jetties at the mouth of the Mississippi River. He was a member of the 1874 jetty board and the 1878 engineer board to improve low-water navigation on the Mississippi immediately prior to be named a member of the Mississippi River Commission. He was a Member of the MRC from 1879-1895 and served two terms as President.
1st term: 1882–1884
2nd term: 1888–1895

Comstock was elected as a member of the National Academy of Sciences in 1884.

He compiled two of the early books on the Comstock lineage, including "Some Descendants of SAMUEL COMSTOCK of Providence RI" in 1905.

Cyrus was appointed to sit on the jury for the trial of those implicated in the assination of Abraham Lincoln, but he was substitued.
Andrew Johnson, President
Executive Order - Special Orders: 211
May 6, 1865
WAR DEPARTMENT,
ADJUTANT-GENERAL'S OFFICE
4. A military commission is hereby appointed to meet at Washington, D.C., on Monday, the 8th day of May, 1865, at 9 o'clock a. m., or as soon thereafter as practicable, for the trial of David E. Herold, George A. Atzerodt, Lewis Payne, Michael O'Laughlin, Edward Spangler, Samuel Arnold, Mary E. Surratt, Samuel A. Mudd, and such other prisoners as may be brought before it, implicated in the murder of the late President, Abraham Lincoln, and the attempted assassination of the Hon. William H. Seward, Secretary of State, and in an alleged conspiracy to assassinate other officers of the Federal Government at Washington City, and their alders and abettors.
Detail for the court.
Major-General David Hunter, United States Volunteers.
Major-General Lewis Wallace, United States Volunteers.
Brevet Major-General August V. Kautz, United States Volunteers.
Brigadier-General Albion P. Howe, United States Volunteers.
Brigadier-General Robert S. Foster, United States Volunteers.
Brevet Brigadier-General Cyrus B. Comstock,* United States Volunteers.
Brigadier-General T. M. Harris, United States Volunteers.
Brevet Colonel Horace Porter,+ aid-de-camp.
Lieutenant-Colonel David R. Clendenin, Eighth Illinois Cavalry.
Brigadier-General Joseph Holt, Judge-Advocate-General, United States Army, is appointed the judge-advocate and recorder of the commission, to be aided by such assistant or special judge-advocate as he may designate.
The commission will sit without regard to hours.
By order of the President of the United States:
E. D. TOWNSEND,
Assistant Adjutant-General.
*Brevet Brigadier-General James A. Ekin substituted;
+Brevet Colonel C. H. Tompkins substituted; see Special Orders, No. 210

Executive Order - Special Orders: 216
May 9, 1865
WAR DEPARTMENT,
ADJUTANT-GENERAL'S OFFICE
91. Brevet Brigadier-General Cyrus B. Comstock, United States Volunteers, and Brevet Colonel Horace Porter, aid-de-camp, are hereby relieved from duty as members of the military commission appointed in Special Orders, No. 211, paragraph 4, dated "War Department, Adjutant-General's Office, Washington, May 6, 1865," and Brevet Brigadier-General James A. Ekin, United States Volunteers, and Brevet Colonel C. H. Tompkins, United States Army, are detailed in their places, respectively.
"The American Presidency Project"
http://www.presidency.ucsb.edu/

Birth	3 Feb 1831	Wrentham, Norfolk County, Massachusetts.
Death	29 May 1910

Father	Nathan Comstock (1806 - 1858)
Mother	Betsey Cook (1805 - 1887)
Sibling	Ellen Comstock (1837 - 1914)

Father	Stephen Comstock (1758 - )
Mother	Hannah Aldrich ( - )
Sibling	Arioch Comstock (1770 - 1835)
Sibling	Stephen Comstock (1777 - 1865)
Sibling	Arnold Comstock (1779 - 1819)
Sibling	Hannah Comstock (1780 - 1820)
Sibling	Nathan Comstock (1781 - 1846)
Sibling	Asahel Comstock (1786 - 1829)
Sibling	Mary Comstock (1790 - )
Sibling	George Comstock (1794 - 1870)