T. B. Harbottle
Theosophical Society involvement
Harbottle was admitted as a Theosophical Society member in London on January 7, 1885.
On October 8, 1888, Harbottle was appointed to a committee proposing rules for formation of a British Section of the Theosophical Society, along with Archibald Keightley, Henry Steel Olcott, John Varley, and A. P. Sinnett.
He was active in the lodge for several years. For example, on January 17, 1889 and at several other meetings, he took the chair at a lodge meeting at 17, Lansdowne Road when the group was studying slokas of the Stanzas of Dzyan.
Lansdowne Road was also the location of an encounter with the astral form of Mahatma Morya:
Mr. Harbottle and others one evening during Lodge session saw plainly the astral form of a Hindu sitting and calm ly watching the people. Indeed, so plain was the sight that only when some one sat down into this visitor, causing his disappearance, did Mr. Harbottle exclaim “He wasn't there at all,” very excitedly. The picture on the easel is that of an old Eastern friend of H.P.B.’s — of her Master, in fact, as she often said.
Involvement in Mahatma Letter
In 1888 Mabel Collins sent a letter to Mr. Harbottle expressing concern about Archibald Keightley, as a means of casting doubt on Helena Petrovna Blavatsky. Koot Hoomi copied it and sent the copy with a message of his own to Madame Blavatsky to warn her of the situation. These letters are Number 58a and 58b in Letters from the Masters of the Wisdom, First Series. In editions 1945-1974, before the First Series was resequenced in 1988, these were called Letter 45a and Letter 45b. 
Harbottle wrote several articles for Theosophical journals.
- "Modern Spiritualism" Broad Views v3 (April 1905), 349.
- "Karma and Free Will" Lucifer v3 (October, 1888), 169.
- "Reincarnation" Theosophical Siftings 1.6 (1888), 1.
- "Brotherhood" Lucifer v1 (November, 1887), 212.
He also authored or coauthored several books:
- Dictionary of Battles. New York: E. P. Dutton, 1905. It is available from Hathitrust.
- Dictionary of Quotations (Classical).
- Dictionary of Quotations (French and Italian).
- Dictionary of Quotations (Spanish).
- Dictionary of Quotations, Latin.
- Dictionary of Historical Allusions: a guide to names, nicknames, sobriquets, and similar appellations for alliances, canons, codes, compromises, concordats ....
- Theosophical Society General Membership Register, 1875-1942 at http://tsmembers.org/. See book 1, entry 3119 (website file: 1B/7).
- "Theosophical Activities" Lucifer 3.15 (November, 1888), 260.
- Richard Groves letter to Boris de Zirkoff, quoting the Minute Book of the Blavatsky Lodge. March 6, 1956. Theosophical Society in England correspondence. Boris de Zirkoff Papers. Records Series 22. Theosophical Society in America Archives.
- Transactions of the Blavatsky Lodge of the Theosophical Society, January 17, 1889. (London: Theosophical Publishing Society, 1990), 17.
- William Quan Judge, "Habitations of H.P.B." The Path 7.2 (May, 1892), 38.
- C. Jinarajadasa, Letters from the Masters of the Wisdom, First Series (Adyar, Chennai, India: Theosophical Publishing House, 2011), 120-121, 171-172.