| RefNo | MS/119/2/19 |
| Level | File |
| Title | Letter from Charles James Buchanan Riddell, Toronto to Humphrey Lloyd, Trinity College, Dublin |
| Date | 14 January 1841 |
| Description | Riddell updates Lloyd on his health, and work conducted at the Toronto observatory. Discussion on the relative position of the magnet. Riddell asked Mr [William Cranch] Bond’s brother-in-law to send two magnets to be remagnetised. The two magnets sent by Lloyd arrived in November, discussion on their time of vibration with the stirrup. Riddell’s illness has prevented him from making any observations since the middle of November.
Riddell does not believe the corrections for the coefficient of horizontal force and vertical force magnetometers will be appreciable. Discussion on the constant correction to the readings of the declination. Riddell discusses his reasons for placing a weak magnet in the declination instrument. Riddell thanks Lloyd for ordering the long scales from [Thomas] Grubb.
Riddell will send Lloyd the details of the temperature correction observations. [Charles] Younghusband has taken a series of observations with one magnet. Discussion regarding the plan for the subterranean observatory at Munich.
Riddell discusses the temperature of the observatory. Discussion about the long scale of the declination. Since the occupation of the new observatory Riddell has been using Gauss’s scale and mirror for the horizontal force. Discussion regarding Riddell’s comments on the times of vibration of vertical force in the horizontal plane.
Riddell discusses his illness. His medical attendants recommend moving to the south for a change of climate. Younghusband has been living at the observatory and for the last two months and had complete superintendence of the observations. To get satisfactory results for the temperature correction Riddell was unable to take any absolute determinations. |
| Extent | 6p |
| 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 |