| RefNo | HSF/2/1/75 |
| Previous numbers | 32.8.58 and 32.8.58A |
| Level | Item |
| Title | Letter from John Herschel, Dehra, to [James Thomas] Walker |
| Creator | Herschel; John (1837-1921); British army officer and astronomer |
| Date | 15 November 1864 |
| Description | Walker will be surprised to hear from Herschel so soon, but he is sending some papers [not present] and wishes to introduce them. He kept his opinions on the reduction of their work to himself, but he was disgusted by [George Biddell] Airy's 'notes' on the subject and feared that Walker would feel obliged to accept them. Airy's views are founded upon a narrow appreciation of their difficulties and after Walker's letter in which he said that the ideas might be useful unless they hit on anything better, Herschel offers his own scheme. He sends it at the eleventh hour of Walker's stay in England, so that he might consult Airy again on the legitimacy of the ideas, although Herschel vouches that they are practical. He has titled the enclosure 'Geodesy as it should be' and intended to send it to his father, but decided to send it to Walker first, and once he had read it, he should forward it to his father's address. Herschel expands on the difficulty of local attraction, secondary in England, but important in a large country such as India, and Airy has overlooked this; he has also confused two distinct problems. Herschel discusses the reduction of the whole series forming the North West Quadrilateral and his attempts to provide accurate linear elements for reducing secondary work. He has yet to put his scheme into practice, but thinks that what he intended for the secondary work may be good enough for the principal work too. He wishes to know if Walker takes the same general view; his own opinion is tentative, since he is isolated and had no-one to discuss this with. He lists the points he alludes to, which are evident in the enclosed paper. Herschel recognises that the letter will reach him at about Christmas time, and recommends a second reading while Walker is at sea. He notes his own Christmas plans. |
| Extent | 8p. |
| Format | Manuscript |
| PhysicalDescription | Ink on paper |
| AccessStatus | Open |
Fellows associated with this archive
| Code | PersonName | Dates |
| NA7955 | Herschel; John (1837 - 1921); Colonel; military engineer, surveyor and astronomer | 1837 - 1921 |