| RefNo | MS/119/2/70 |
| Level | Item |
| Title | Letter from Charles James Buchanan Riddell, Maidstone to Humphrey Lloyd |
| Date | 12 February 1846 |
| Description | Riddell has finished correcting [his instructions], discusses the changes he has made and his travel plans. Discussion on Lloyd’s method for the induction correction. Riddell notes that Lloyd’s method is more likely mathematically correct and convenient, however he is now unable to make any alterations to the formula, as the books have already been printed and circulated. Riddell corrected the angles in order to allow the calculation of the coefficients P and Q, and altered the absolute declination part. Discussion on the induction inclinometer, and separation of permanent and temporary induced magnetism.
Riddell discusses [John Henry] Lefroy’s observations and notes that there are no errors from electricity in the metal rings greater than those attending the determination of inertia with cylinder weights. Riddell has changed the paragraph relating to the differences of absolute values.
Riddell has never used the glass scales and they had been recommended by [Johann von] Lamont.
Riddell has been in Maidstone since the middle of last week after giving over his magnetic duties [at Woolwich]. Riddell plans to go to town next week, then on to Scotland, and then perhaps visiting Canada again to see old friends and the observatory again.
Riddell would like Lloyd to look over papers relating to the mean diurnal variations arranged with a view to probable errors of coefficients. |
| Extent | 9p |
| Format | Manuscript |
| PhysicalDescription | Ink on paper |
| AccessStatus | Open |
Fellows associated with this archive
| Code | PersonName | Dates |
| NA7327 | Riddell; Charles James Buchanan (1817 - 1903) | 1817 - 1903 |
| NA8252 | Lloyd; Humphrey (1800 - 1881) | 1800 - 1881 |