Search: Herschel, John in addressee 
Walker, James Thomas in author 
1860-1869::1864 in date 
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Showing 14 of 4 items

From:
James Thomas Walker
To:
Sir John Herschel
Date:
[2 January 1864]
Source of text:
RS:HS 18.13
Summary:

Received JH's two letters acknowledging receipt of 'Volume of Tables of Heights' of the Great Trigonometrical Survey of India. Hopes to visit JH and discuss phenomenon of terrestrial refraction. Received valuable assistance on tables from JH's son John.

Contributor:
John Herschel Project
From:
James Thomas Walker
To:
Sir John Herschel
Date:
[6 June 1864]
Source of text:
RS:HS 18.14
Summary:

Returned from Gloucestershire. Will visit Collingwood on Monday.

Contributor:
John Herschel Project
From:
James Thomas Walker
To:
Sir John Herschel
Date:
[9 December 1864]
Source of text:
RS:HS 18.15
Summary:

Sent JH 'Index Chart' of Great Trigonometrical Survey of India. Compares five triangulation methods: longitudinal series, George Everest's, G. B. Airy's, that of JH's son John, and minimum squares. JH's son and bride avoided cyclone that destroyed Calcutta Observatory.

Contributor:
John Herschel Project
From:
James Thomas Walker
To:
Sir John Herschel
Date:
[15 December 1864]
Source of text:
RS:HS 18.17
Summary:

Indian Triangulation chart showed progress to May 1862. Explains why arcs of meridians and parallels were chosen over diagonal braces. G. B. Airy's method of determining errors helped. Will take note and package from Maria [Herschel] to JH's son John.

Contributor:
John Herschel Project