| RefNo | HSF/2/1/48 |
| Previous numbers | 32.8.31, 32.8.31A-E |
| Level | Item |
| Title | Letter from J [John] Herschel, Murree, to 'Dearest Father' [Sir John Frederick William Herschel] |
| Creator | Herschel; John (1837-1921); British army officer and astronomer |
| Date | 3-28 June 1860 |
| Description | He sits down to answer his father's and mother's letters, received that morning, and he received the Quetelet a little earlier. He is disappointed in the book and he is back to where he was. His father has Sir George Everest's 'Arc Book', and therefore John need not go through the whole process in use for correcting the observed angles. He has no faith in the methodology being used there, 'when expediency and mathematical reasoning are jumbled together'. He refers his father to a few pages of Everest's introduction and he explains the way in which the observed angle is obtained, and his own difficulties in the calculations. [From 12 June] He finds that he was mistaken in mail times and can continue his letter. John describes the weekly routine of work, consisting of five days mainly of computation after which he is fatigued. He does a good deal of walking and exercises his horse; the animal that fell down the khud will be better in about a fortnight. The office consists of Herschel, [Henry Ravenshaw] Thuillier and [James Palladio] Basevi with three civil assistants. He describes how the original field observations were kept and copied, then the various computations founded on the angle books. [From 15 June] John continues his description of their computations from the point of returning to make azimuth observations in the field; the principal triangulations and work with the great theodolite from principal stations, the latter which he has been engaged upon fro the last six weeks. The most laborious exercise was the processing of six to ten observations taken of different peaks to form 'any number of available bases'. John relates the 'disheartening' number of these which will be cut, as considered unfit. He sends a table [present] to give examples of distances in feet obtained by different bases and triangles. He continues to describe computations made as soon as the principal triangulations were finished, including the heights of the various stations. He and Thuillier are now computing the azimuth observed at Dajel and when complete the regular season's work will be at an end, although there will be extra work. There was an enormous discrepency between results obtained between Basevi's party and Keelan's, which means that Basevi's party will go to re-observe one of Keelan's polygons which seems unsatisfactory. Therefore they now know where next season's work is to be: a series at Mitten Kot [Mithankot] and then into Kashmir during the following season. This is known as the Coast Series, formerly in the charge of Major Strange, who has to leave the Survey having reached his regimental majority. The great question occupying the Survey is whether Colonel [Andrew Scott] Waugh will retire and who his successor might be. Major Walker is to go to Mussoorie to take over the Surveyor-General's office while Waugh is on leave at Calcutta [Kolkata]. [From 27 June] John describes a comet seen on 24 June, so large that it is a mystery why it had not been noticed before: it had a star-like nucleus and a tail of six to eight degrees in length. He gives two sketches. [From 28 June] He confirms that it is a comet and not a star, and nearer to Jupiter. He gives thanks for journals and asks what he thinks of the abstract of transits by Thuillier and himself [present].
With two enclosures, headed: 'Abstracts of Transits taken by Lts. Thuillier & Herschel with Troughton & Simms Great Theodolite April 1860'; and 'Abstracts of Distances to Hill Peaks'. |
| Extent | 20p. |
| Format | Manuscript |
| PhysicalDescription | Ink on paper |
| AccessStatus | Open |
Fellows associated with this archive
| Code | PersonName | Dates |
| NA7955 | Herschel; John (1837 - 1921) | 1837 - 1921 |