| RefNo | HSF/2/1/76 |
| Previous numbers | 32.8.60, 32.8.60A-B and 32.8.59 |
| Level | Item |
| Title | Letter from J H [John Herschel], Dehra and Mussoorie, to 'Dear Father' [Sir John Frederick William Herschel] |
| Creator | Herschel; John (1837-1921); British army officer and astronomer |
| Date | 6-30 May 1865 |
| Description | With a heading note: 'Please read the last sheet (the P.S. first)'.
He received his father's letter of 1 April in response of his own of 5-21 February and at the risk of mistakes, he will continue the subject of the 'unfortunate Lemma'. He notes a quotation from his own letter which has obscured his meaning and he can see how his mistake came about. John discusses equations and relations, saying that the particular kind of equation he had in mind does not express any relation. He attempts to explain with equations, and follows his father's lead with a test of experiment. He states that if the Lemma stands the test of algebraic demonstration and numerical trial, it must be true, even if not applicable to particular theory or calculus. He outlines what fault he had and believes that discussions of this kind, persevered for too long, become unpleasant. In mathematics, 'surrender, save on conviction, is wrong'; he has derived benefit from the discussion, but he had better not write more. He has an unhappy knack of putting a right thing wrong. He outlines the history of his own reasoning on the subject and he is now satisfied. His father should remember that he is in India, without a mathematical library to help him though difficulties. He was writing for Indian surveyors, not for English mathematicians, and wished to spare them uncertainty; he thinks differently now. He asks if the Lemma supplies the link, which he thinks it does, but his father's view is hidden.
Postscript: he writes to say that he recants and retracts, as all that he has said on the Lemma is nonsense. He wishes his father to know what he was aiming at and he wishes to make a more careful attempt at wording the proposition to avoid pitfalls. In enunciating a true proposition, his father will see how he fell into error. He sets this out and concludes by asking if the Lemma does supply the necessary clue. |
| Extent | 15p. |
| 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 |